diff --git a/include/os/freebsd/spl/sys/disp.h b/include/os/freebsd/spl/sys/disp.h index 2be1b76e4334..d46a7d2c0143 100644 --- a/include/os/freebsd/spl/sys/disp.h +++ b/include/os/freebsd/spl/sys/disp.h @@ -1,36 +1,38 @@ /* * Copyright (c) 2013 Andriy Gapon * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #ifndef _OPENSOLARIS_SYS_DISP_H_ #define _OPENSOLARIS_SYS_DISP_H_ #include +#define KPREEMPT_SYNC (-1) + #define kpreempt(x) kern_yield(PRI_USER) #endif /* _OPENSOLARIS_SYS_DISP_H_ */ diff --git a/include/os/freebsd/spl/sys/timer.h b/include/os/freebsd/spl/sys/timer.h index d4694bb7c09c..7ff77e9b1b74 100644 --- a/include/os/freebsd/spl/sys/timer.h +++ b/include/os/freebsd/spl/sys/timer.h @@ -1,38 +1,36 @@ /* * Copyright (c) 2020 iXsystems, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #ifndef _SPL_TIMER_H_ #define _SPL_TIMER_H_ #define ddi_time_after(a, b) ((a) > (b)) #define ddi_time_after64(a, b) ((a) > (b)) #define usleep_range(wakeup, wakeupepsilon) \ pause_sbt("usleep_range", ustosbt(wakeup), \ ustosbt(wakeupepsilon - wakeup), 0) - -#define schedule() pause("schedule", 1) #endif diff --git a/include/os/freebsd/zfs/sys/zfs_context_os.h b/include/os/freebsd/zfs/sys/zfs_context_os.h index 867199501396..1ce72330412c 100644 --- a/include/os/freebsd/zfs/sys/zfs_context_os.h +++ b/include/os/freebsd/zfs/sys/zfs_context_os.h @@ -1,90 +1,88 @@ /* * Copyright (c) 2020 iXsystems, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #ifndef ZFS_CONTEXT_OS_H_ #define ZFS_CONTEXT_OS_H_ #include #include #include #include_next #include #include #include #include #include #include #include #if KSTACK_PAGES * PAGE_SIZE >= 16384 #define HAVE_LARGE_STACKS 1 #endif -#define cond_resched() kern_yield(PRI_USER) - #define taskq_create_sysdc(a, b, d, e, p, dc, f) \ ((void) sizeof (dc), taskq_create(a, b, maxclsyspri, d, e, f)) #define tsd_create(keyp, destructor) do { \ *(keyp) = osd_thread_register((destructor)); \ KASSERT(*(keyp) > 0, ("cannot register OSD")); \ } while (0) #define tsd_destroy(keyp) osd_thread_deregister(*(keyp)) #define tsd_get(key) osd_thread_get(curthread, (key)) #define tsd_set(key, value) osd_thread_set(curthread, (key), (value)) #define fm_panic panic extern int zfs_debug_level; extern struct mtx zfs_debug_mtx; #define ZFS_LOG(lvl, ...) do { \ if (((lvl) & 0xff) <= zfs_debug_level) { \ mtx_lock(&zfs_debug_mtx); \ printf("%s:%u[%d]: ", \ __func__, __LINE__, (lvl)); \ printf(__VA_ARGS__); \ printf("\n"); \ if ((lvl) & 0x100) \ kdb_backtrace(); \ mtx_unlock(&zfs_debug_mtx); \ } \ } while (0) #define MSEC_TO_TICK(msec) (howmany((hrtime_t)(msec) * hz, MILLISEC)) extern int hz; extern int tick; typedef int fstrans_cookie_t; #define spl_fstrans_mark() (0) #define spl_fstrans_unmark(x) (x = 0) #define signal_pending(x) SIGPENDING(x) #define current curthread #define thread_join(x) typedef struct opensolaris_utsname utsname_t; extern utsname_t *utsname(void); extern int spa_import_rootpool(const char *name, bool checkpointrewind); #endif diff --git a/include/os/linux/spl/sys/disp.h b/include/os/linux/spl/sys/disp.h index e106d3c5438e..c8be6ffbf10f 100644 --- a/include/os/linux/spl/sys/disp.h +++ b/include/os/linux/spl/sys/disp.h @@ -1,33 +1,35 @@ /* * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC. * Copyright (C) 2007 The Regents of the University of California. * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). * Written by Brian Behlendorf . * UCRL-CODE-235197 * * This file is part of the SPL, Solaris Porting Layer. * * The SPL is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. * * The SPL is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. * * You should have received a copy of the GNU General Public License along * with the SPL. If not, see . */ #ifndef _SPL_DISP_H #define _SPL_DISP_H #include -#define kpreempt(unused) schedule() +#define KPREEMPT_SYNC (-1) + +#define kpreempt(unused) cond_resched() #define kpreempt_disable() preempt_disable() #define kpreempt_enable() preempt_enable() #endif /* SPL_DISP_H */ diff --git a/include/sys/zfs_context.h b/include/sys/zfs_context.h index aa4f78789631..83ed97fbec7f 100644 --- a/include/sys/zfs_context.h +++ b/include/sys/zfs_context.h @@ -1,777 +1,778 @@ /* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or https://opensource.org/licenses/CDDL-1.0. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright 2011 Nexenta Systems, Inc. All rights reserved. * Copyright (c) 2012, 2018 by Delphix. All rights reserved. * Copyright (c) 2012, Joyent, Inc. All rights reserved. */ #ifndef _SYS_ZFS_CONTEXT_H #define _SYS_ZFS_CONTEXT_H #ifdef __cplusplus extern "C" { #endif /* * This code compiles in three different contexts. When __KERNEL__ is defined, * the code uses "unix-like" kernel interfaces. When _STANDALONE is defined, the * code is running in a reduced capacity environment of the boot loader which is * generally a subset of both POSIX and kernel interfaces (with a few unique * interfaces too). When neither are defined, it's in a userland POSIX or * similar environment. */ #if defined(__KERNEL__) || defined(_STANDALONE) #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #else /* _KERNEL || _STANDALONE */ #define _SYS_MUTEX_H #define _SYS_RWLOCK_H #define _SYS_CONDVAR_H #define _SYS_VNODE_H #define _SYS_VFS_H #define _SYS_SUNDDI_H #define _SYS_CALLB_H #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Stack */ #define noinline __attribute__((noinline)) #define likely(x) __builtin_expect((x), 1) #define unlikely(x) __builtin_expect((x), 0) /* * Debugging */ /* * Note that we are not using the debugging levels. */ #define CE_CONT 0 /* continuation */ #define CE_NOTE 1 /* notice */ #define CE_WARN 2 /* warning */ #define CE_PANIC 3 /* panic */ #define CE_IGNORE 4 /* print nothing */ /* * ZFS debugging */ extern void dprintf_setup(int *argc, char **argv); extern void cmn_err(int, const char *, ...); extern void vcmn_err(int, const char *, va_list); extern __attribute__((noreturn)) void panic(const char *, ...); extern __attribute__((noreturn)) void vpanic(const char *, va_list); #define fm_panic panic /* * DTrace SDT probes have different signatures in userland than they do in * the kernel. If they're being used in kernel code, re-define them out of * existence for their counterparts in libzpool. * * Here's an example of how to use the set-error probes in userland: * zfs$target:::set-error /arg0 == EBUSY/ {stack();} * * Here's an example of how to use DTRACE_PROBE probes in userland: * If there is a probe declared as follows: * DTRACE_PROBE2(zfs__probe_name, uint64_t, blkid, dnode_t *, dn); * Then you can use it as follows: * zfs$target:::probe2 /copyinstr(arg0) == "zfs__probe_name"/ * {printf("%u %p\n", arg1, arg2);} */ #ifdef DTRACE_PROBE #undef DTRACE_PROBE #endif /* DTRACE_PROBE */ #define DTRACE_PROBE(a) #ifdef DTRACE_PROBE1 #undef DTRACE_PROBE1 #endif /* DTRACE_PROBE1 */ #define DTRACE_PROBE1(a, b, c) #ifdef DTRACE_PROBE2 #undef DTRACE_PROBE2 #endif /* DTRACE_PROBE2 */ #define DTRACE_PROBE2(a, b, c, d, e) #ifdef DTRACE_PROBE3 #undef DTRACE_PROBE3 #endif /* DTRACE_PROBE3 */ #define DTRACE_PROBE3(a, b, c, d, e, f, g) #ifdef DTRACE_PROBE4 #undef DTRACE_PROBE4 #endif /* DTRACE_PROBE4 */ #define DTRACE_PROBE4(a, b, c, d, e, f, g, h, i) /* * Tunables. */ typedef struct zfs_kernel_param { const char *name; /* unused stub */ } zfs_kernel_param_t; #define ZFS_MODULE_PARAM(scope_prefix, name_prefix, name, type, perm, desc) #define ZFS_MODULE_PARAM_ARGS void #define ZFS_MODULE_PARAM_CALL(scope_prefix, name_prefix, name, setfunc, \ getfunc, perm, desc) /* * Threads. */ typedef pthread_t kthread_t; #define TS_RUN 0x00000002 #define TS_JOINABLE 0x00000004 #define curthread ((void *)(uintptr_t)pthread_self()) -#define kpreempt(x) yield() #define getcomm() "unknown" #define thread_create_named(name, stk, stksize, func, arg, len, \ pp, state, pri) \ zk_thread_create(func, arg, stksize, state) #define thread_create(stk, stksize, func, arg, len, pp, state, pri) \ zk_thread_create(func, arg, stksize, state) #define thread_exit() pthread_exit(NULL) #define thread_join(t) pthread_join((pthread_t)(t), NULL) #define newproc(f, a, cid, pri, ctp, pid) (ENOSYS) /* in libzpool, p0 exists only to have its address taken */ typedef struct proc { uintptr_t this_is_never_used_dont_dereference_it; } proc_t; extern struct proc p0; #define curproc (&p0) #define PS_NONE -1 extern kthread_t *zk_thread_create(void (*func)(void *), void *arg, size_t stksize, int state); #define issig(why) (FALSE) #define ISSIG(thr, why) (FALSE) +#define KPREEMPT_SYNC (-1) + +#define kpreempt(x) sched_yield() #define kpreempt_disable() ((void)0) #define kpreempt_enable() ((void)0) -#define cond_resched() sched_yield() /* * Mutexes */ typedef struct kmutex { pthread_mutex_t m_lock; pthread_t m_owner; } kmutex_t; #define MUTEX_DEFAULT 0 #define MUTEX_NOLOCKDEP MUTEX_DEFAULT #define MUTEX_HELD(mp) pthread_equal((mp)->m_owner, pthread_self()) #define MUTEX_NOT_HELD(mp) !MUTEX_HELD(mp) extern void mutex_init(kmutex_t *mp, char *name, int type, void *cookie); extern void mutex_destroy(kmutex_t *mp); extern void mutex_enter(kmutex_t *mp); extern void mutex_exit(kmutex_t *mp); extern int mutex_tryenter(kmutex_t *mp); #define NESTED_SINGLE 1 #define mutex_enter_nested(mp, class) mutex_enter(mp) /* * RW locks */ typedef struct krwlock { pthread_rwlock_t rw_lock; pthread_t rw_owner; uint_t rw_readers; } krwlock_t; typedef int krw_t; #define RW_READER 0 #define RW_WRITER 1 #define RW_DEFAULT RW_READER #define RW_NOLOCKDEP RW_READER #define RW_READ_HELD(rw) ((rw)->rw_readers > 0) #define RW_WRITE_HELD(rw) pthread_equal((rw)->rw_owner, pthread_self()) #define RW_LOCK_HELD(rw) (RW_READ_HELD(rw) || RW_WRITE_HELD(rw)) extern void rw_init(krwlock_t *rwlp, char *name, int type, void *arg); extern void rw_destroy(krwlock_t *rwlp); extern void rw_enter(krwlock_t *rwlp, krw_t rw); extern int rw_tryenter(krwlock_t *rwlp, krw_t rw); extern int rw_tryupgrade(krwlock_t *rwlp); extern void rw_exit(krwlock_t *rwlp); #define rw_downgrade(rwlp) do { } while (0) /* * Credentials */ extern uid_t crgetuid(cred_t *cr); extern uid_t crgetruid(cred_t *cr); extern gid_t crgetgid(cred_t *cr); extern int crgetngroups(cred_t *cr); extern gid_t *crgetgroups(cred_t *cr); /* * Condition variables */ typedef pthread_cond_t kcondvar_t; #define CV_DEFAULT 0 #define CALLOUT_FLAG_ABSOLUTE 0x2 extern void cv_init(kcondvar_t *cv, char *name, int type, void *arg); extern void cv_destroy(kcondvar_t *cv); extern void cv_wait(kcondvar_t *cv, kmutex_t *mp); extern int cv_wait_sig(kcondvar_t *cv, kmutex_t *mp); extern int cv_timedwait(kcondvar_t *cv, kmutex_t *mp, clock_t abstime); extern int cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim, hrtime_t res, int flag); extern void cv_signal(kcondvar_t *cv); extern void cv_broadcast(kcondvar_t *cv); #define cv_timedwait_io(cv, mp, at) cv_timedwait(cv, mp, at) #define cv_timedwait_idle(cv, mp, at) cv_timedwait(cv, mp, at) #define cv_timedwait_sig(cv, mp, at) cv_timedwait(cv, mp, at) #define cv_wait_io(cv, mp) cv_wait(cv, mp) #define cv_wait_idle(cv, mp) cv_wait(cv, mp) #define cv_wait_io_sig(cv, mp) cv_wait_sig(cv, mp) #define cv_timedwait_sig_hires(cv, mp, t, r, f) \ cv_timedwait_hires(cv, mp, t, r, f) #define cv_timedwait_idle_hires(cv, mp, t, r, f) \ cv_timedwait_hires(cv, mp, t, r, f) /* * Thread-specific data */ #define tsd_get(k) pthread_getspecific(k) #define tsd_set(k, v) pthread_setspecific(k, v) #define tsd_create(kp, d) pthread_key_create((pthread_key_t *)kp, d) #define tsd_destroy(kp) /* nothing */ #ifdef __FreeBSD__ typedef off_t loff_t; #endif /* * kstat creation, installation and deletion */ extern kstat_t *kstat_create(const char *, int, const char *, const char *, uchar_t, ulong_t, uchar_t); extern void kstat_install(kstat_t *); extern void kstat_delete(kstat_t *); extern void kstat_set_raw_ops(kstat_t *ksp, int (*headers)(char *buf, size_t size), int (*data)(char *buf, size_t size, void *data), void *(*addr)(kstat_t *ksp, loff_t index)); /* * procfs list manipulation */ typedef struct procfs_list { void *pl_private; kmutex_t pl_lock; list_t pl_list; uint64_t pl_next_id; size_t pl_node_offset; } procfs_list_t; #ifndef __cplusplus struct seq_file { }; void seq_printf(struct seq_file *m, const char *fmt, ...); typedef struct procfs_list_node { list_node_t pln_link; uint64_t pln_id; } procfs_list_node_t; void procfs_list_install(const char *module, const char *submodule, const char *name, mode_t mode, procfs_list_t *procfs_list, int (*show)(struct seq_file *f, void *p), int (*show_header)(struct seq_file *f), int (*clear)(procfs_list_t *procfs_list), size_t procfs_list_node_off); void procfs_list_uninstall(procfs_list_t *procfs_list); void procfs_list_destroy(procfs_list_t *procfs_list); void procfs_list_add(procfs_list_t *procfs_list, void *p); #endif /* * Kernel memory */ #define KM_SLEEP UMEM_NOFAIL #define KM_PUSHPAGE KM_SLEEP #define KM_NOSLEEP UMEM_DEFAULT #define KM_NORMALPRI 0 /* not needed with UMEM_DEFAULT */ #define KMC_NODEBUG UMC_NODEBUG #define KMC_KVMEM 0x0 #define kmem_alloc(_s, _f) umem_alloc(_s, _f) #define kmem_zalloc(_s, _f) umem_zalloc(_s, _f) #define kmem_free(_b, _s) umem_free(_b, _s) #define vmem_alloc(_s, _f) kmem_alloc(_s, _f) #define vmem_zalloc(_s, _f) kmem_zalloc(_s, _f) #define vmem_free(_b, _s) kmem_free(_b, _s) #define kmem_cache_create(_a, _b, _c, _d, _e, _f, _g, _h, _i) \ umem_cache_create(_a, _b, _c, _d, _e, _f, _g, _h, _i) #define kmem_cache_destroy(_c) umem_cache_destroy(_c) #define kmem_cache_alloc(_c, _f) umem_cache_alloc(_c, _f) #define kmem_cache_free(_c, _b) umem_cache_free(_c, _b) #define kmem_debugging() 0 #define kmem_cache_reap_now(_c) umem_cache_reap_now(_c); #define kmem_cache_set_move(_c, _cb) /* nothing */ #define POINTER_INVALIDATE(_pp) /* nothing */ #define POINTER_IS_VALID(_p) 0 typedef umem_cache_t kmem_cache_t; typedef enum kmem_cbrc { KMEM_CBRC_YES, KMEM_CBRC_NO, KMEM_CBRC_LATER, KMEM_CBRC_DONT_NEED, KMEM_CBRC_DONT_KNOW } kmem_cbrc_t; /* * Task queues */ #define TASKQ_NAMELEN 31 typedef uintptr_t taskqid_t; typedef void (task_func_t)(void *); typedef struct taskq_ent { struct taskq_ent *tqent_next; struct taskq_ent *tqent_prev; task_func_t *tqent_func; void *tqent_arg; uintptr_t tqent_flags; } taskq_ent_t; typedef struct taskq { char tq_name[TASKQ_NAMELEN + 1]; kmutex_t tq_lock; krwlock_t tq_threadlock; kcondvar_t tq_dispatch_cv; kcondvar_t tq_wait_cv; kthread_t **tq_threadlist; int tq_flags; int tq_active; int tq_nthreads; int tq_nalloc; int tq_minalloc; int tq_maxalloc; kcondvar_t tq_maxalloc_cv; int tq_maxalloc_wait; taskq_ent_t *tq_freelist; taskq_ent_t tq_task; } taskq_t; #define TQENT_FLAG_PREALLOC 0x1 /* taskq_dispatch_ent used */ #define TASKQ_PREPOPULATE 0x0001 #define TASKQ_CPR_SAFE 0x0002 /* Use CPR safe protocol */ #define TASKQ_DYNAMIC 0x0004 /* Use dynamic thread scheduling */ #define TASKQ_THREADS_CPU_PCT 0x0008 /* Scale # threads by # cpus */ #define TASKQ_DC_BATCH 0x0010 /* Mark threads as batch */ #define TQ_SLEEP KM_SLEEP /* Can block for memory */ #define TQ_NOSLEEP KM_NOSLEEP /* cannot block for memory; may fail */ #define TQ_NOQUEUE 0x02 /* Do not enqueue if can't dispatch */ #define TQ_FRONT 0x08 /* Queue in front */ #define TASKQID_INVALID ((taskqid_t)0) extern taskq_t *system_taskq; extern taskq_t *system_delay_taskq; extern taskq_t *taskq_create(const char *, int, pri_t, int, int, uint_t); #define taskq_create_proc(a, b, c, d, e, p, f) \ (taskq_create(a, b, c, d, e, f)) #define taskq_create_sysdc(a, b, d, e, p, dc, f) \ ((void) sizeof (dc), taskq_create(a, b, maxclsyspri, d, e, f)) extern taskqid_t taskq_dispatch(taskq_t *, task_func_t, void *, uint_t); extern taskqid_t taskq_dispatch_delay(taskq_t *, task_func_t, void *, uint_t, clock_t); extern void taskq_dispatch_ent(taskq_t *, task_func_t, void *, uint_t, taskq_ent_t *); extern int taskq_empty_ent(taskq_ent_t *); extern void taskq_init_ent(taskq_ent_t *); extern void taskq_destroy(taskq_t *); extern void taskq_wait(taskq_t *); extern void taskq_wait_id(taskq_t *, taskqid_t); extern void taskq_wait_outstanding(taskq_t *, taskqid_t); extern int taskq_member(taskq_t *, kthread_t *); extern taskq_t *taskq_of_curthread(void); extern int taskq_cancel_id(taskq_t *, taskqid_t); extern void system_taskq_init(void); extern void system_taskq_fini(void); #define XVA_MAPSIZE 3 #define XVA_MAGIC 0x78766174 extern char *vn_dumpdir; #define AV_SCANSTAMP_SZ 32 /* length of anti-virus scanstamp */ typedef struct xoptattr { inode_timespec_t xoa_createtime; /* Create time of file */ uint8_t xoa_archive; uint8_t xoa_system; uint8_t xoa_readonly; uint8_t xoa_hidden; uint8_t xoa_nounlink; uint8_t xoa_immutable; uint8_t xoa_appendonly; uint8_t xoa_nodump; uint8_t xoa_settable; uint8_t xoa_opaque; uint8_t xoa_av_quarantined; uint8_t xoa_av_modified; uint8_t xoa_av_scanstamp[AV_SCANSTAMP_SZ]; uint8_t xoa_reparse; uint8_t xoa_offline; uint8_t xoa_sparse; } xoptattr_t; typedef struct vattr { uint_t va_mask; /* bit-mask of attributes */ u_offset_t va_size; /* file size in bytes */ } vattr_t; typedef struct xvattr { vattr_t xva_vattr; /* Embedded vattr structure */ uint32_t xva_magic; /* Magic Number */ uint32_t xva_mapsize; /* Size of attr bitmap (32-bit words) */ uint32_t *xva_rtnattrmapp; /* Ptr to xva_rtnattrmap[] */ uint32_t xva_reqattrmap[XVA_MAPSIZE]; /* Requested attrs */ uint32_t xva_rtnattrmap[XVA_MAPSIZE]; /* Returned attrs */ xoptattr_t xva_xoptattrs; /* Optional attributes */ } xvattr_t; typedef struct vsecattr { uint_t vsa_mask; /* See below */ int vsa_aclcnt; /* ACL entry count */ void *vsa_aclentp; /* pointer to ACL entries */ int vsa_dfaclcnt; /* default ACL entry count */ void *vsa_dfaclentp; /* pointer to default ACL entries */ size_t vsa_aclentsz; /* ACE size in bytes of vsa_aclentp */ } vsecattr_t; #define AT_MODE 0x00002 #define AT_UID 0x00004 #define AT_GID 0x00008 #define AT_FSID 0x00010 #define AT_NODEID 0x00020 #define AT_NLINK 0x00040 #define AT_SIZE 0x00080 #define AT_ATIME 0x00100 #define AT_MTIME 0x00200 #define AT_CTIME 0x00400 #define AT_RDEV 0x00800 #define AT_BLKSIZE 0x01000 #define AT_NBLOCKS 0x02000 #define AT_SEQ 0x08000 #define AT_XVATTR 0x10000 #define CRCREAT 0 #define F_FREESP 11 #define FIGNORECASE 0x80000 /* request case-insensitive lookups */ /* * Random stuff */ #define ddi_get_lbolt() (gethrtime() >> 23) #define ddi_get_lbolt64() (gethrtime() >> 23) #define hz 119 /* frequency when using gethrtime() >> 23 for lbolt */ #define ddi_time_before(a, b) (a < b) #define ddi_time_after(a, b) ddi_time_before(b, a) #define ddi_time_before_eq(a, b) (!ddi_time_after(a, b)) #define ddi_time_after_eq(a, b) ddi_time_before_eq(b, a) #define ddi_time_before64(a, b) (a < b) #define ddi_time_after64(a, b) ddi_time_before64(b, a) #define ddi_time_before_eq64(a, b) (!ddi_time_after64(a, b)) #define ddi_time_after_eq64(a, b) ddi_time_before_eq64(b, a) extern void delay(clock_t ticks); #define SEC_TO_TICK(sec) ((sec) * hz) #define MSEC_TO_TICK(msec) (howmany((hrtime_t)(msec) * hz, MILLISEC)) #define USEC_TO_TICK(usec) (howmany((hrtime_t)(usec) * hz, MICROSEC)) #define NSEC_TO_TICK(nsec) (howmany((hrtime_t)(nsec) * hz, NANOSEC)) #define max_ncpus 64 #define boot_ncpus (sysconf(_SC_NPROCESSORS_ONLN)) /* * Process priorities as defined by setpriority(2) and getpriority(2). */ #define minclsyspri 19 #define maxclsyspri -20 #define defclsyspri 0 #define CPU_SEQID ((uintptr_t)pthread_self() & (max_ncpus - 1)) #define CPU_SEQID_UNSTABLE CPU_SEQID #define kcred NULL #define CRED() NULL #define ptob(x) ((x) * PAGESIZE) #define NN_DIVISOR_1000 (1U << 0) #define NN_NUMBUF_SZ (6) extern uint64_t physmem; extern const char *random_path; extern const char *urandom_path; extern int highbit64(uint64_t i); extern int lowbit64(uint64_t i); extern int random_get_bytes(uint8_t *ptr, size_t len); extern int random_get_pseudo_bytes(uint8_t *ptr, size_t len); static __inline__ uint32_t random_in_range(uint32_t range) { uint32_t r; ASSERT(range != 0); if (range == 1) return (0); (void) random_get_pseudo_bytes((uint8_t *)&r, sizeof (r)); return (r % range); } extern void kernel_init(int mode); extern void kernel_fini(void); extern void random_init(void); extern void random_fini(void); struct spa; extern void show_pool_stats(struct spa *); extern int set_global_var(char const *arg); typedef struct callb_cpr { kmutex_t *cc_lockp; } callb_cpr_t; #define CALLB_CPR_INIT(cp, lockp, func, name) { \ (cp)->cc_lockp = lockp; \ } #define CALLB_CPR_SAFE_BEGIN(cp) { \ ASSERT(MUTEX_HELD((cp)->cc_lockp)); \ } #define CALLB_CPR_SAFE_END(cp, lockp) { \ ASSERT(MUTEX_HELD((cp)->cc_lockp)); \ } #define CALLB_CPR_EXIT(cp) { \ ASSERT(MUTEX_HELD((cp)->cc_lockp)); \ mutex_exit((cp)->cc_lockp); \ } #define zone_dataset_visible(x, y) (1) #define INGLOBALZONE(z) (1) extern uint32_t zone_get_hostid(void *zonep); extern char *kmem_vasprintf(const char *fmt, va_list adx); extern char *kmem_asprintf(const char *fmt, ...); #define kmem_strfree(str) kmem_free((str), strlen(str) + 1) #define kmem_strdup(s) strdup(s) /* * Hostname information */ extern int ddi_strtoull(const char *str, char **nptr, int base, u_longlong_t *result); typedef struct utsname utsname_t; extern utsname_t *utsname(void); /* ZFS Boot Related stuff. */ struct _buf { intptr_t _fd; }; struct bootstat { uint64_t st_size; }; typedef struct ace_object { uid_t a_who; uint32_t a_access_mask; uint16_t a_flags; uint16_t a_type; uint8_t a_obj_type[16]; uint8_t a_inherit_obj_type[16]; } ace_object_t; #define ACE_ACCESS_ALLOWED_OBJECT_ACE_TYPE 0x05 #define ACE_ACCESS_DENIED_OBJECT_ACE_TYPE 0x06 #define ACE_SYSTEM_AUDIT_OBJECT_ACE_TYPE 0x07 #define ACE_SYSTEM_ALARM_OBJECT_ACE_TYPE 0x08 extern int zfs_secpolicy_snapshot_perms(const char *name, cred_t *cr); extern int zfs_secpolicy_rename_perms(const char *from, const char *to, cred_t *cr); extern int zfs_secpolicy_destroy_perms(const char *name, cred_t *cr); extern int secpolicy_zfs(const cred_t *cr); extern int secpolicy_zfs_proc(const cred_t *cr, proc_t *proc); extern zoneid_t getzoneid(void); /* SID stuff */ typedef struct ksiddomain { uint_t kd_ref; uint_t kd_len; char *kd_name; } ksiddomain_t; ksiddomain_t *ksid_lookupdomain(const char *); void ksiddomain_rele(ksiddomain_t *); #define DDI_SLEEP KM_SLEEP #define ddi_log_sysevent(_a, _b, _c, _d, _e, _f, _g) \ sysevent_post_event(_c, _d, _b, "libzpool", _e, _f) #define zfs_sleep_until(wakeup) \ do { \ hrtime_t delta = wakeup - gethrtime(); \ struct timespec ts; \ ts.tv_sec = delta / NANOSEC; \ ts.tv_nsec = delta % NANOSEC; \ (void) nanosleep(&ts, NULL); \ } while (0) typedef int fstrans_cookie_t; extern fstrans_cookie_t spl_fstrans_mark(void); extern void spl_fstrans_unmark(fstrans_cookie_t); extern int __spl_pf_fstrans_check(void); extern int kmem_cache_reap_active(void); /* * Kernel modules */ #define __init #define __exit #endif /* _KERNEL || _STANDALONE */ #ifdef __cplusplus }; #endif #endif /* _SYS_ZFS_CONTEXT_H */ diff --git a/module/zfs/arc.c b/module/zfs/arc.c index 980dc60d0cc0..b9969bff534e 100644 --- a/module/zfs/arc.c +++ b/module/zfs/arc.c @@ -1,11200 +1,11200 @@ /* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or https://opensource.org/licenses/CDDL-1.0. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2018, Joyent, Inc. * Copyright (c) 2011, 2020, Delphix. All rights reserved. * Copyright (c) 2014, Saso Kiselkov. All rights reserved. * Copyright (c) 2017, Nexenta Systems, Inc. All rights reserved. * Copyright (c) 2019, loli10K . All rights reserved. * Copyright (c) 2020, George Amanakis. All rights reserved. * Copyright (c) 2019, Klara Inc. * Copyright (c) 2019, Allan Jude * Copyright (c) 2020, The FreeBSD Foundation [1] * * [1] Portions of this software were developed by Allan Jude * under sponsorship from the FreeBSD Foundation. */ /* * DVA-based Adjustable Replacement Cache * * While much of the theory of operation used here is * based on the self-tuning, low overhead replacement cache * presented by Megiddo and Modha at FAST 2003, there are some * significant differences: * * 1. The Megiddo and Modha model assumes any page is evictable. * Pages in its cache cannot be "locked" into memory. This makes * the eviction algorithm simple: evict the last page in the list. * This also make the performance characteristics easy to reason * about. Our cache is not so simple. At any given moment, some * subset of the blocks in the cache are un-evictable because we * have handed out a reference to them. Blocks are only evictable * when there are no external references active. This makes * eviction far more problematic: we choose to evict the evictable * blocks that are the "lowest" in the list. * * There are times when it is not possible to evict the requested * space. In these circumstances we are unable to adjust the cache * size. To prevent the cache growing unbounded at these times we * implement a "cache throttle" that slows the flow of new data * into the cache until we can make space available. * * 2. The Megiddo and Modha model assumes a fixed cache size. * Pages are evicted when the cache is full and there is a cache * miss. Our model has a variable sized cache. It grows with * high use, but also tries to react to memory pressure from the * operating system: decreasing its size when system memory is * tight. * * 3. The Megiddo and Modha model assumes a fixed page size. All * elements of the cache are therefore exactly the same size. So * when adjusting the cache size following a cache miss, its simply * a matter of choosing a single page to evict. In our model, we * have variable sized cache blocks (ranging from 512 bytes to * 128K bytes). We therefore choose a set of blocks to evict to make * space for a cache miss that approximates as closely as possible * the space used by the new block. * * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" * by N. Megiddo & D. Modha, FAST 2003 */ /* * The locking model: * * A new reference to a cache buffer can be obtained in two * ways: 1) via a hash table lookup using the DVA as a key, * or 2) via one of the ARC lists. The arc_read() interface * uses method 1, while the internal ARC algorithms for * adjusting the cache use method 2. We therefore provide two * types of locks: 1) the hash table lock array, and 2) the * ARC list locks. * * Buffers do not have their own mutexes, rather they rely on the * hash table mutexes for the bulk of their protection (i.e. most * fields in the arc_buf_hdr_t are protected by these mutexes). * * buf_hash_find() returns the appropriate mutex (held) when it * locates the requested buffer in the hash table. It returns * NULL for the mutex if the buffer was not in the table. * * buf_hash_remove() expects the appropriate hash mutex to be * already held before it is invoked. * * Each ARC state also has a mutex which is used to protect the * buffer list associated with the state. When attempting to * obtain a hash table lock while holding an ARC list lock you * must use: mutex_tryenter() to avoid deadlock. Also note that * the active state mutex must be held before the ghost state mutex. * * It as also possible to register a callback which is run when the * arc_meta_limit is reached and no buffers can be safely evicted. In * this case the arc user should drop a reference on some arc buffers so * they can be reclaimed and the arc_meta_limit honored. For example, * when using the ZPL each dentry holds a references on a znode. These * dentries must be pruned before the arc buffer holding the znode can * be safely evicted. * * Note that the majority of the performance stats are manipulated * with atomic operations. * * The L2ARC uses the l2ad_mtx on each vdev for the following: * * - L2ARC buflist creation * - L2ARC buflist eviction * - L2ARC write completion, which walks L2ARC buflists * - ARC header destruction, as it removes from L2ARC buflists * - ARC header release, as it removes from L2ARC buflists */ /* * ARC operation: * * Every block that is in the ARC is tracked by an arc_buf_hdr_t structure. * This structure can point either to a block that is still in the cache or to * one that is only accessible in an L2 ARC device, or it can provide * information about a block that was recently evicted. If a block is * only accessible in the L2ARC, then the arc_buf_hdr_t only has enough * information to retrieve it from the L2ARC device. This information is * stored in the l2arc_buf_hdr_t sub-structure of the arc_buf_hdr_t. A block * that is in this state cannot access the data directly. * * Blocks that are actively being referenced or have not been evicted * are cached in the L1ARC. The L1ARC (l1arc_buf_hdr_t) is a structure within * the arc_buf_hdr_t that will point to the data block in memory. A block can * only be read by a consumer if it has an l1arc_buf_hdr_t. The L1ARC * caches data in two ways -- in a list of ARC buffers (arc_buf_t) and * also in the arc_buf_hdr_t's private physical data block pointer (b_pabd). * * The L1ARC's data pointer may or may not be uncompressed. The ARC has the * ability to store the physical data (b_pabd) associated with the DVA of the * arc_buf_hdr_t. Since the b_pabd is a copy of the on-disk physical block, * it will match its on-disk compression characteristics. This behavior can be * disabled by setting 'zfs_compressed_arc_enabled' to B_FALSE. When the * compressed ARC functionality is disabled, the b_pabd will point to an * uncompressed version of the on-disk data. * * Data in the L1ARC is not accessed by consumers of the ARC directly. Each * arc_buf_hdr_t can have multiple ARC buffers (arc_buf_t) which reference it. * Each ARC buffer (arc_buf_t) is being actively accessed by a specific ARC * consumer. The ARC will provide references to this data and will keep it * cached until it is no longer in use. The ARC caches only the L1ARC's physical * data block and will evict any arc_buf_t that is no longer referenced. The * amount of memory consumed by the arc_buf_ts' data buffers can be seen via the * "overhead_size" kstat. * * Depending on the consumer, an arc_buf_t can be requested in uncompressed or * compressed form. The typical case is that consumers will want uncompressed * data, and when that happens a new data buffer is allocated where the data is * decompressed for them to use. Currently the only consumer who wants * compressed arc_buf_t's is "zfs send", when it streams data exactly as it * exists on disk. When this happens, the arc_buf_t's data buffer is shared * with the arc_buf_hdr_t. * * Here is a diagram showing an arc_buf_hdr_t referenced by two arc_buf_t's. The * first one is owned by a compressed send consumer (and therefore references * the same compressed data buffer as the arc_buf_hdr_t) and the second could be * used by any other consumer (and has its own uncompressed copy of the data * buffer). * * arc_buf_hdr_t * +-----------+ * | fields | * | common to | * | L1- and | * | L2ARC | * +-----------+ * | l2arc_buf_hdr_t * | | * +-----------+ * | l1arc_buf_hdr_t * | | arc_buf_t * | b_buf +------------>+-----------+ arc_buf_t * | b_pabd +-+ |b_next +---->+-----------+ * +-----------+ | |-----------| |b_next +-->NULL * | |b_comp = T | +-----------+ * | |b_data +-+ |b_comp = F | * | +-----------+ | |b_data +-+ * +->+------+ | +-----------+ | * compressed | | | | * data | |<--------------+ | uncompressed * +------+ compressed, | data * shared +-->+------+ * data | | * | | * +------+ * * When a consumer reads a block, the ARC must first look to see if the * arc_buf_hdr_t is cached. If the hdr is cached then the ARC allocates a new * arc_buf_t and either copies uncompressed data into a new data buffer from an * existing uncompressed arc_buf_t, decompresses the hdr's b_pabd buffer into a * new data buffer, or shares the hdr's b_pabd buffer, depending on whether the * hdr is compressed and the desired compression characteristics of the * arc_buf_t consumer. If the arc_buf_t ends up sharing data with the * arc_buf_hdr_t and both of them are uncompressed then the arc_buf_t must be * the last buffer in the hdr's b_buf list, however a shared compressed buf can * be anywhere in the hdr's list. * * The diagram below shows an example of an uncompressed ARC hdr that is * sharing its data with an arc_buf_t (note that the shared uncompressed buf is * the last element in the buf list): * * arc_buf_hdr_t * +-----------+ * | | * | | * | | * +-----------+ * l2arc_buf_hdr_t| | * | | * +-----------+ * l1arc_buf_hdr_t| | * | | arc_buf_t (shared) * | b_buf +------------>+---------+ arc_buf_t * | | |b_next +---->+---------+ * | b_pabd +-+ |---------| |b_next +-->NULL * +-----------+ | | | +---------+ * | |b_data +-+ | | * | +---------+ | |b_data +-+ * +->+------+ | +---------+ | * | | | | * uncompressed | | | | * data +------+ | | * ^ +->+------+ | * | uncompressed | | | * | data | | | * | +------+ | * +---------------------------------+ * * Writing to the ARC requires that the ARC first discard the hdr's b_pabd * since the physical block is about to be rewritten. The new data contents * will be contained in the arc_buf_t. As the I/O pipeline performs the write, * it may compress the data before writing it to disk. The ARC will be called * with the transformed data and will memcpy the transformed on-disk block into * a newly allocated b_pabd. Writes are always done into buffers which have * either been loaned (and hence are new and don't have other readers) or * buffers which have been released (and hence have their own hdr, if there * were originally other readers of the buf's original hdr). This ensures that * the ARC only needs to update a single buf and its hdr after a write occurs. * * When the L2ARC is in use, it will also take advantage of the b_pabd. The * L2ARC will always write the contents of b_pabd to the L2ARC. This means * that when compressed ARC is enabled that the L2ARC blocks are identical * to the on-disk block in the main data pool. This provides a significant * advantage since the ARC can leverage the bp's checksum when reading from the * L2ARC to determine if the contents are valid. However, if the compressed * ARC is disabled, then the L2ARC's block must be transformed to look * like the physical block in the main data pool before comparing the * checksum and determining its validity. * * The L1ARC has a slightly different system for storing encrypted data. * Raw (encrypted + possibly compressed) data has a few subtle differences from * data that is just compressed. The biggest difference is that it is not * possible to decrypt encrypted data (or vice-versa) if the keys aren't loaded. * The other difference is that encryption cannot be treated as a suggestion. * If a caller would prefer compressed data, but they actually wind up with * uncompressed data the worst thing that could happen is there might be a * performance hit. If the caller requests encrypted data, however, we must be * sure they actually get it or else secret information could be leaked. Raw * data is stored in hdr->b_crypt_hdr.b_rabd. An encrypted header, therefore, * may have both an encrypted version and a decrypted version of its data at * once. When a caller needs a raw arc_buf_t, it is allocated and the data is * copied out of this header. To avoid complications with b_pabd, raw buffers * cannot be shared. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef _KERNEL /* set with ZFS_DEBUG=watch, to enable watchpoints on frozen buffers */ boolean_t arc_watch = B_FALSE; #endif /* * This thread's job is to keep enough free memory in the system, by * calling arc_kmem_reap_soon() plus arc_reduce_target_size(), which improves * arc_available_memory(). */ static zthr_t *arc_reap_zthr; /* * This thread's job is to keep arc_size under arc_c, by calling * arc_evict(), which improves arc_is_overflowing(). */ static zthr_t *arc_evict_zthr; static arc_buf_hdr_t **arc_state_evict_markers; static int arc_state_evict_marker_count; static kmutex_t arc_evict_lock; static boolean_t arc_evict_needed = B_FALSE; /* * Count of bytes evicted since boot. */ static uint64_t arc_evict_count; /* * List of arc_evict_waiter_t's, representing threads waiting for the * arc_evict_count to reach specific values. */ static list_t arc_evict_waiters; /* * When arc_is_overflowing(), arc_get_data_impl() waits for this percent of * the requested amount of data to be evicted. For example, by default for * every 2KB that's evicted, 1KB of it may be "reused" by a new allocation. * Since this is above 100%, it ensures that progress is made towards getting * arc_size under arc_c. Since this is finite, it ensures that allocations * can still happen, even during the potentially long time that arc_size is * more than arc_c. */ static int zfs_arc_eviction_pct = 200; /* * The number of headers to evict in arc_evict_state_impl() before * dropping the sublist lock and evicting from another sublist. A lower * value means we're more likely to evict the "correct" header (i.e. the * oldest header in the arc state), but comes with higher overhead * (i.e. more invocations of arc_evict_state_impl()). */ static int zfs_arc_evict_batch_limit = 10; /* number of seconds before growing cache again */ int arc_grow_retry = 5; /* * Minimum time between calls to arc_kmem_reap_soon(). */ static const int arc_kmem_cache_reap_retry_ms = 1000; /* shift of arc_c for calculating overflow limit in arc_get_data_impl */ static int zfs_arc_overflow_shift = 8; /* shift of arc_c for calculating both min and max arc_p */ static int arc_p_min_shift = 4; /* log2(fraction of arc to reclaim) */ int arc_shrink_shift = 7; /* percent of pagecache to reclaim arc to */ #ifdef _KERNEL uint_t zfs_arc_pc_percent = 0; #endif /* * log2(fraction of ARC which must be free to allow growing). * I.e. If there is less than arc_c >> arc_no_grow_shift free memory, * when reading a new block into the ARC, we will evict an equal-sized block * from the ARC. * * This must be less than arc_shrink_shift, so that when we shrink the ARC, * we will still not allow it to grow. */ int arc_no_grow_shift = 5; /* * minimum lifespan of a prefetch block in clock ticks * (initialized in arc_init()) */ static int arc_min_prefetch_ms; static int arc_min_prescient_prefetch_ms; /* * If this percent of memory is free, don't throttle. */ int arc_lotsfree_percent = 10; /* * The arc has filled available memory and has now warmed up. */ boolean_t arc_warm; /* * These tunables are for performance analysis. */ unsigned long zfs_arc_max = 0; unsigned long zfs_arc_min = 0; unsigned long zfs_arc_meta_limit = 0; unsigned long zfs_arc_meta_min = 0; static unsigned long zfs_arc_dnode_limit = 0; static unsigned long zfs_arc_dnode_reduce_percent = 10; static int zfs_arc_grow_retry = 0; static int zfs_arc_shrink_shift = 0; static int zfs_arc_p_min_shift = 0; int zfs_arc_average_blocksize = 8 * 1024; /* 8KB */ /* * ARC dirty data constraints for arc_tempreserve_space() throttle: * * total dirty data limit * * anon block dirty limit * * each pool's anon allowance */ static const unsigned long zfs_arc_dirty_limit_percent = 50; static const unsigned long zfs_arc_anon_limit_percent = 25; static const unsigned long zfs_arc_pool_dirty_percent = 20; /* * Enable or disable compressed arc buffers. */ int zfs_compressed_arc_enabled = B_TRUE; /* * ARC will evict meta buffers that exceed arc_meta_limit. This * tunable make arc_meta_limit adjustable for different workloads. */ static unsigned long zfs_arc_meta_limit_percent = 75; /* * Percentage that can be consumed by dnodes of ARC meta buffers. */ static unsigned long zfs_arc_dnode_limit_percent = 10; /* * These tunables are Linux-specific */ static unsigned long zfs_arc_sys_free = 0; static int zfs_arc_min_prefetch_ms = 0; static int zfs_arc_min_prescient_prefetch_ms = 0; static int zfs_arc_p_dampener_disable = 1; static int zfs_arc_meta_prune = 10000; static int zfs_arc_meta_strategy = ARC_STRATEGY_META_BALANCED; static int zfs_arc_meta_adjust_restarts = 4096; static int zfs_arc_lotsfree_percent = 10; /* * Number of arc_prune threads */ static int zfs_arc_prune_task_threads = 1; /* The 6 states: */ arc_state_t ARC_anon; arc_state_t ARC_mru; arc_state_t ARC_mru_ghost; arc_state_t ARC_mfu; arc_state_t ARC_mfu_ghost; arc_state_t ARC_l2c_only; arc_stats_t arc_stats = { { "hits", KSTAT_DATA_UINT64 }, { "misses", KSTAT_DATA_UINT64 }, { "demand_data_hits", KSTAT_DATA_UINT64 }, { "demand_data_misses", KSTAT_DATA_UINT64 }, { "demand_metadata_hits", KSTAT_DATA_UINT64 }, { "demand_metadata_misses", KSTAT_DATA_UINT64 }, { "prefetch_data_hits", KSTAT_DATA_UINT64 }, { "prefetch_data_misses", KSTAT_DATA_UINT64 }, { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, { "mru_hits", KSTAT_DATA_UINT64 }, { "mru_ghost_hits", KSTAT_DATA_UINT64 }, { "mfu_hits", KSTAT_DATA_UINT64 }, { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, { "deleted", KSTAT_DATA_UINT64 }, { "mutex_miss", KSTAT_DATA_UINT64 }, { "access_skip", KSTAT_DATA_UINT64 }, { "evict_skip", KSTAT_DATA_UINT64 }, { "evict_not_enough", KSTAT_DATA_UINT64 }, { "evict_l2_cached", KSTAT_DATA_UINT64 }, { "evict_l2_eligible", KSTAT_DATA_UINT64 }, { "evict_l2_eligible_mfu", KSTAT_DATA_UINT64 }, { "evict_l2_eligible_mru", KSTAT_DATA_UINT64 }, { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, { "evict_l2_skip", KSTAT_DATA_UINT64 }, { "hash_elements", KSTAT_DATA_UINT64 }, { "hash_elements_max", KSTAT_DATA_UINT64 }, { "hash_collisions", KSTAT_DATA_UINT64 }, { "hash_chains", KSTAT_DATA_UINT64 }, { "hash_chain_max", KSTAT_DATA_UINT64 }, { "p", KSTAT_DATA_UINT64 }, { "c", KSTAT_DATA_UINT64 }, { "c_min", KSTAT_DATA_UINT64 }, { "c_max", KSTAT_DATA_UINT64 }, { "size", KSTAT_DATA_UINT64 }, { "compressed_size", KSTAT_DATA_UINT64 }, { "uncompressed_size", KSTAT_DATA_UINT64 }, { "overhead_size", KSTAT_DATA_UINT64 }, { "hdr_size", KSTAT_DATA_UINT64 }, { "data_size", KSTAT_DATA_UINT64 }, { "metadata_size", KSTAT_DATA_UINT64 }, { "dbuf_size", KSTAT_DATA_UINT64 }, { "dnode_size", KSTAT_DATA_UINT64 }, { "bonus_size", KSTAT_DATA_UINT64 }, #if defined(COMPAT_FREEBSD11) { "other_size", KSTAT_DATA_UINT64 }, #endif { "anon_size", KSTAT_DATA_UINT64 }, { "anon_evictable_data", KSTAT_DATA_UINT64 }, { "anon_evictable_metadata", KSTAT_DATA_UINT64 }, { "mru_size", KSTAT_DATA_UINT64 }, { "mru_evictable_data", KSTAT_DATA_UINT64 }, { "mru_evictable_metadata", KSTAT_DATA_UINT64 }, { "mru_ghost_size", KSTAT_DATA_UINT64 }, { "mru_ghost_evictable_data", KSTAT_DATA_UINT64 }, { "mru_ghost_evictable_metadata", KSTAT_DATA_UINT64 }, { "mfu_size", KSTAT_DATA_UINT64 }, { "mfu_evictable_data", KSTAT_DATA_UINT64 }, { "mfu_evictable_metadata", KSTAT_DATA_UINT64 }, { "mfu_ghost_size", KSTAT_DATA_UINT64 }, { "mfu_ghost_evictable_data", KSTAT_DATA_UINT64 }, { "mfu_ghost_evictable_metadata", KSTAT_DATA_UINT64 }, { "l2_hits", KSTAT_DATA_UINT64 }, { "l2_misses", KSTAT_DATA_UINT64 }, { "l2_prefetch_asize", KSTAT_DATA_UINT64 }, { "l2_mru_asize", KSTAT_DATA_UINT64 }, { "l2_mfu_asize", KSTAT_DATA_UINT64 }, { "l2_bufc_data_asize", KSTAT_DATA_UINT64 }, { "l2_bufc_metadata_asize", KSTAT_DATA_UINT64 }, { "l2_feeds", KSTAT_DATA_UINT64 }, { "l2_rw_clash", KSTAT_DATA_UINT64 }, { "l2_read_bytes", KSTAT_DATA_UINT64 }, { "l2_write_bytes", KSTAT_DATA_UINT64 }, { "l2_writes_sent", KSTAT_DATA_UINT64 }, { "l2_writes_done", KSTAT_DATA_UINT64 }, { "l2_writes_error", KSTAT_DATA_UINT64 }, { "l2_writes_lock_retry", KSTAT_DATA_UINT64 }, { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, { "l2_evict_reading", KSTAT_DATA_UINT64 }, { "l2_evict_l1cached", KSTAT_DATA_UINT64 }, { "l2_free_on_write", KSTAT_DATA_UINT64 }, { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, { "l2_cksum_bad", KSTAT_DATA_UINT64 }, { "l2_io_error", KSTAT_DATA_UINT64 }, { "l2_size", KSTAT_DATA_UINT64 }, { "l2_asize", KSTAT_DATA_UINT64 }, { "l2_hdr_size", KSTAT_DATA_UINT64 }, { "l2_log_blk_writes", KSTAT_DATA_UINT64 }, { "l2_log_blk_avg_asize", KSTAT_DATA_UINT64 }, { "l2_log_blk_asize", KSTAT_DATA_UINT64 }, { "l2_log_blk_count", KSTAT_DATA_UINT64 }, { "l2_data_to_meta_ratio", KSTAT_DATA_UINT64 }, { "l2_rebuild_success", KSTAT_DATA_UINT64 }, { "l2_rebuild_unsupported", KSTAT_DATA_UINT64 }, { "l2_rebuild_io_errors", KSTAT_DATA_UINT64 }, { "l2_rebuild_dh_errors", KSTAT_DATA_UINT64 }, { "l2_rebuild_cksum_lb_errors", KSTAT_DATA_UINT64 }, { "l2_rebuild_lowmem", KSTAT_DATA_UINT64 }, { "l2_rebuild_size", KSTAT_DATA_UINT64 }, { "l2_rebuild_asize", KSTAT_DATA_UINT64 }, { "l2_rebuild_bufs", KSTAT_DATA_UINT64 }, { "l2_rebuild_bufs_precached", KSTAT_DATA_UINT64 }, { "l2_rebuild_log_blks", KSTAT_DATA_UINT64 }, { "memory_throttle_count", KSTAT_DATA_UINT64 }, { "memory_direct_count", KSTAT_DATA_UINT64 }, { "memory_indirect_count", KSTAT_DATA_UINT64 }, { "memory_all_bytes", KSTAT_DATA_UINT64 }, { "memory_free_bytes", KSTAT_DATA_UINT64 }, { "memory_available_bytes", KSTAT_DATA_INT64 }, { "arc_no_grow", KSTAT_DATA_UINT64 }, { "arc_tempreserve", KSTAT_DATA_UINT64 }, { "arc_loaned_bytes", KSTAT_DATA_UINT64 }, { "arc_prune", KSTAT_DATA_UINT64 }, { "arc_meta_used", KSTAT_DATA_UINT64 }, { "arc_meta_limit", KSTAT_DATA_UINT64 }, { "arc_dnode_limit", KSTAT_DATA_UINT64 }, { "arc_meta_max", KSTAT_DATA_UINT64 }, { "arc_meta_min", KSTAT_DATA_UINT64 }, { "async_upgrade_sync", KSTAT_DATA_UINT64 }, { "demand_hit_predictive_prefetch", KSTAT_DATA_UINT64 }, { "demand_hit_prescient_prefetch", KSTAT_DATA_UINT64 }, { "arc_need_free", KSTAT_DATA_UINT64 }, { "arc_sys_free", KSTAT_DATA_UINT64 }, { "arc_raw_size", KSTAT_DATA_UINT64 }, { "cached_only_in_progress", KSTAT_DATA_UINT64 }, { "abd_chunk_waste_size", KSTAT_DATA_UINT64 }, }; arc_sums_t arc_sums; #define ARCSTAT_MAX(stat, val) { \ uint64_t m; \ while ((val) > (m = arc_stats.stat.value.ui64) && \ (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ continue; \ } /* * We define a macro to allow ARC hits/misses to be easily broken down by * two separate conditions, giving a total of four different subtypes for * each of hits and misses (so eight statistics total). */ #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ if (cond1) { \ if (cond2) { \ ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ } else { \ ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ } \ } else { \ if (cond2) { \ ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ } else { \ ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ } \ } /* * This macro allows us to use kstats as floating averages. Each time we * update this kstat, we first factor it and the update value by * ARCSTAT_AVG_FACTOR to shrink the new value's contribution to the overall * average. This macro assumes that integer loads and stores are atomic, but * is not safe for multiple writers updating the kstat in parallel (only the * last writer's update will remain). */ #define ARCSTAT_F_AVG_FACTOR 3 #define ARCSTAT_F_AVG(stat, value) \ do { \ uint64_t x = ARCSTAT(stat); \ x = x - x / ARCSTAT_F_AVG_FACTOR + \ (value) / ARCSTAT_F_AVG_FACTOR; \ ARCSTAT(stat) = x; \ } while (0) static kstat_t *arc_ksp; /* * There are several ARC variables that are critical to export as kstats -- * but we don't want to have to grovel around in the kstat whenever we wish to * manipulate them. For these variables, we therefore define them to be in * terms of the statistic variable. This assures that we are not introducing * the possibility of inconsistency by having shadow copies of the variables, * while still allowing the code to be readable. */ #define arc_tempreserve ARCSTAT(arcstat_tempreserve) #define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes) #define arc_meta_limit ARCSTAT(arcstat_meta_limit) /* max size for metadata */ /* max size for dnodes */ #define arc_dnode_size_limit ARCSTAT(arcstat_dnode_limit) #define arc_meta_min ARCSTAT(arcstat_meta_min) /* min size for metadata */ #define arc_need_free ARCSTAT(arcstat_need_free) /* waiting to be evicted */ hrtime_t arc_growtime; list_t arc_prune_list; kmutex_t arc_prune_mtx; taskq_t *arc_prune_taskq; #define GHOST_STATE(state) \ ((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \ (state) == arc_l2c_only) #define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_FLAG_IN_HASH_TABLE) #define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS) #define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_FLAG_IO_ERROR) #define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_FLAG_PREFETCH) #define HDR_PRESCIENT_PREFETCH(hdr) \ ((hdr)->b_flags & ARC_FLAG_PRESCIENT_PREFETCH) #define HDR_COMPRESSION_ENABLED(hdr) \ ((hdr)->b_flags & ARC_FLAG_COMPRESSED_ARC) #define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_FLAG_L2CACHE) #define HDR_L2_READING(hdr) \ (((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS) && \ ((hdr)->b_flags & ARC_FLAG_HAS_L2HDR)) #define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITING) #define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_FLAG_L2_EVICTED) #define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITE_HEAD) #define HDR_PROTECTED(hdr) ((hdr)->b_flags & ARC_FLAG_PROTECTED) #define HDR_NOAUTH(hdr) ((hdr)->b_flags & ARC_FLAG_NOAUTH) #define HDR_SHARED_DATA(hdr) ((hdr)->b_flags & ARC_FLAG_SHARED_DATA) #define HDR_ISTYPE_METADATA(hdr) \ ((hdr)->b_flags & ARC_FLAG_BUFC_METADATA) #define HDR_ISTYPE_DATA(hdr) (!HDR_ISTYPE_METADATA(hdr)) #define HDR_HAS_L1HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L1HDR) #define HDR_HAS_L2HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L2HDR) #define HDR_HAS_RABD(hdr) \ (HDR_HAS_L1HDR(hdr) && HDR_PROTECTED(hdr) && \ (hdr)->b_crypt_hdr.b_rabd != NULL) #define HDR_ENCRYPTED(hdr) \ (HDR_PROTECTED(hdr) && DMU_OT_IS_ENCRYPTED((hdr)->b_crypt_hdr.b_ot)) #define HDR_AUTHENTICATED(hdr) \ (HDR_PROTECTED(hdr) && !DMU_OT_IS_ENCRYPTED((hdr)->b_crypt_hdr.b_ot)) /* For storing compression mode in b_flags */ #define HDR_COMPRESS_OFFSET (highbit64(ARC_FLAG_COMPRESS_0) - 1) #define HDR_GET_COMPRESS(hdr) ((enum zio_compress)BF32_GET((hdr)->b_flags, \ HDR_COMPRESS_OFFSET, SPA_COMPRESSBITS)) #define HDR_SET_COMPRESS(hdr, cmp) BF32_SET((hdr)->b_flags, \ HDR_COMPRESS_OFFSET, SPA_COMPRESSBITS, (cmp)); #define ARC_BUF_LAST(buf) ((buf)->b_next == NULL) #define ARC_BUF_SHARED(buf) ((buf)->b_flags & ARC_BUF_FLAG_SHARED) #define ARC_BUF_COMPRESSED(buf) ((buf)->b_flags & ARC_BUF_FLAG_COMPRESSED) #define ARC_BUF_ENCRYPTED(buf) ((buf)->b_flags & ARC_BUF_FLAG_ENCRYPTED) /* * Other sizes */ #define HDR_FULL_CRYPT_SIZE ((int64_t)sizeof (arc_buf_hdr_t)) #define HDR_FULL_SIZE ((int64_t)offsetof(arc_buf_hdr_t, b_crypt_hdr)) #define HDR_L2ONLY_SIZE ((int64_t)offsetof(arc_buf_hdr_t, b_l1hdr)) /* * Hash table routines */ #define BUF_LOCKS 2048 typedef struct buf_hash_table { uint64_t ht_mask; arc_buf_hdr_t **ht_table; kmutex_t ht_locks[BUF_LOCKS] ____cacheline_aligned; } buf_hash_table_t; static buf_hash_table_t buf_hash_table; #define BUF_HASH_INDEX(spa, dva, birth) \ (buf_hash(spa, dva, birth) & buf_hash_table.ht_mask) #define BUF_HASH_LOCK(idx) (&buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)]) #define HDR_LOCK(hdr) \ (BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth))) uint64_t zfs_crc64_table[256]; /* * Level 2 ARC */ #define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */ #define L2ARC_HEADROOM 2 /* num of writes */ /* * If we discover during ARC scan any buffers to be compressed, we boost * our headroom for the next scanning cycle by this percentage multiple. */ #define L2ARC_HEADROOM_BOOST 200 #define L2ARC_FEED_SECS 1 /* caching interval secs */ #define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */ /* * We can feed L2ARC from two states of ARC buffers, mru and mfu, * and each of the state has two types: data and metadata. */ #define L2ARC_FEED_TYPES 4 /* L2ARC Performance Tunables */ unsigned long l2arc_write_max = L2ARC_WRITE_SIZE; /* def max write size */ unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra warmup write */ unsigned long l2arc_headroom = L2ARC_HEADROOM; /* # of dev writes */ unsigned long l2arc_headroom_boost = L2ARC_HEADROOM_BOOST; unsigned long l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */ unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */ int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ int l2arc_feed_again = B_TRUE; /* turbo warmup */ int l2arc_norw = B_FALSE; /* no reads during writes */ static int l2arc_meta_percent = 33; /* limit on headers size */ /* * L2ARC Internals */ static list_t L2ARC_dev_list; /* device list */ static list_t *l2arc_dev_list; /* device list pointer */ static kmutex_t l2arc_dev_mtx; /* device list mutex */ static l2arc_dev_t *l2arc_dev_last; /* last device used */ static list_t L2ARC_free_on_write; /* free after write buf list */ static list_t *l2arc_free_on_write; /* free after write list ptr */ static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */ static uint64_t l2arc_ndev; /* number of devices */ typedef struct l2arc_read_callback { arc_buf_hdr_t *l2rcb_hdr; /* read header */ blkptr_t l2rcb_bp; /* original blkptr */ zbookmark_phys_t l2rcb_zb; /* original bookmark */ int l2rcb_flags; /* original flags */ abd_t *l2rcb_abd; /* temporary buffer */ } l2arc_read_callback_t; typedef struct l2arc_data_free { /* protected by l2arc_free_on_write_mtx */ abd_t *l2df_abd; size_t l2df_size; arc_buf_contents_t l2df_type; list_node_t l2df_list_node; } l2arc_data_free_t; typedef enum arc_fill_flags { ARC_FILL_LOCKED = 1 << 0, /* hdr lock is held */ ARC_FILL_COMPRESSED = 1 << 1, /* fill with compressed data */ ARC_FILL_ENCRYPTED = 1 << 2, /* fill with encrypted data */ ARC_FILL_NOAUTH = 1 << 3, /* don't attempt to authenticate */ ARC_FILL_IN_PLACE = 1 << 4 /* fill in place (special case) */ } arc_fill_flags_t; typedef enum arc_ovf_level { ARC_OVF_NONE, /* ARC within target size. */ ARC_OVF_SOME, /* ARC is slightly overflowed. */ ARC_OVF_SEVERE /* ARC is severely overflowed. */ } arc_ovf_level_t; static kmutex_t l2arc_feed_thr_lock; static kcondvar_t l2arc_feed_thr_cv; static uint8_t l2arc_thread_exit; static kmutex_t l2arc_rebuild_thr_lock; static kcondvar_t l2arc_rebuild_thr_cv; enum arc_hdr_alloc_flags { ARC_HDR_ALLOC_RDATA = 0x1, ARC_HDR_DO_ADAPT = 0x2, ARC_HDR_USE_RESERVE = 0x4, }; static abd_t *arc_get_data_abd(arc_buf_hdr_t *, uint64_t, const void *, int); static void *arc_get_data_buf(arc_buf_hdr_t *, uint64_t, const void *); static void arc_get_data_impl(arc_buf_hdr_t *, uint64_t, const void *, int); static void arc_free_data_abd(arc_buf_hdr_t *, abd_t *, uint64_t, const void *); static void arc_free_data_buf(arc_buf_hdr_t *, void *, uint64_t, const void *); static void arc_free_data_impl(arc_buf_hdr_t *hdr, uint64_t size, const void *tag); static void arc_hdr_free_abd(arc_buf_hdr_t *, boolean_t); static void arc_hdr_alloc_abd(arc_buf_hdr_t *, int); static void arc_access(arc_buf_hdr_t *, kmutex_t *); static void arc_buf_watch(arc_buf_t *); static arc_buf_contents_t arc_buf_type(arc_buf_hdr_t *); static uint32_t arc_bufc_to_flags(arc_buf_contents_t); static inline void arc_hdr_set_flags(arc_buf_hdr_t *hdr, arc_flags_t flags); static inline void arc_hdr_clear_flags(arc_buf_hdr_t *hdr, arc_flags_t flags); static boolean_t l2arc_write_eligible(uint64_t, arc_buf_hdr_t *); static void l2arc_read_done(zio_t *); static void l2arc_do_free_on_write(void); static void l2arc_hdr_arcstats_update(arc_buf_hdr_t *hdr, boolean_t incr, boolean_t state_only); #define l2arc_hdr_arcstats_increment(hdr) \ l2arc_hdr_arcstats_update((hdr), B_TRUE, B_FALSE) #define l2arc_hdr_arcstats_decrement(hdr) \ l2arc_hdr_arcstats_update((hdr), B_FALSE, B_FALSE) #define l2arc_hdr_arcstats_increment_state(hdr) \ l2arc_hdr_arcstats_update((hdr), B_TRUE, B_TRUE) #define l2arc_hdr_arcstats_decrement_state(hdr) \ l2arc_hdr_arcstats_update((hdr), B_FALSE, B_TRUE) /* * l2arc_exclude_special : A zfs module parameter that controls whether buffers * present on special vdevs are eligibile for caching in L2ARC. If * set to 1, exclude dbufs on special vdevs from being cached to * L2ARC. */ int l2arc_exclude_special = 0; /* * l2arc_mfuonly : A ZFS module parameter that controls whether only MFU * metadata and data are cached from ARC into L2ARC. */ static int l2arc_mfuonly = 0; /* * L2ARC TRIM * l2arc_trim_ahead : A ZFS module parameter that controls how much ahead of * the current write size (l2arc_write_max) we should TRIM if we * have filled the device. It is defined as a percentage of the * write size. If set to 100 we trim twice the space required to * accommodate upcoming writes. A minimum of 64MB will be trimmed. * It also enables TRIM of the whole L2ARC device upon creation or * addition to an existing pool or if the header of the device is * invalid upon importing a pool or onlining a cache device. The * default is 0, which disables TRIM on L2ARC altogether as it can * put significant stress on the underlying storage devices. This * will vary depending of how well the specific device handles * these commands. */ static unsigned long l2arc_trim_ahead = 0; /* * Performance tuning of L2ARC persistence: * * l2arc_rebuild_enabled : A ZFS module parameter that controls whether adding * an L2ARC device (either at pool import or later) will attempt * to rebuild L2ARC buffer contents. * l2arc_rebuild_blocks_min_l2size : A ZFS module parameter that controls * whether log blocks are written to the L2ARC device. If the L2ARC * device is less than 1GB, the amount of data l2arc_evict() * evicts is significant compared to the amount of restored L2ARC * data. In this case do not write log blocks in L2ARC in order * not to waste space. */ static int l2arc_rebuild_enabled = B_TRUE; static unsigned long l2arc_rebuild_blocks_min_l2size = 1024 * 1024 * 1024; /* L2ARC persistence rebuild control routines. */ void l2arc_rebuild_vdev(vdev_t *vd, boolean_t reopen); static __attribute__((noreturn)) void l2arc_dev_rebuild_thread(void *arg); static int l2arc_rebuild(l2arc_dev_t *dev); /* L2ARC persistence read I/O routines. */ static int l2arc_dev_hdr_read(l2arc_dev_t *dev); static int l2arc_log_blk_read(l2arc_dev_t *dev, const l2arc_log_blkptr_t *this_lp, const l2arc_log_blkptr_t *next_lp, l2arc_log_blk_phys_t *this_lb, l2arc_log_blk_phys_t *next_lb, zio_t *this_io, zio_t **next_io); static zio_t *l2arc_log_blk_fetch(vdev_t *vd, const l2arc_log_blkptr_t *lp, l2arc_log_blk_phys_t *lb); static void l2arc_log_blk_fetch_abort(zio_t *zio); /* L2ARC persistence block restoration routines. */ static void l2arc_log_blk_restore(l2arc_dev_t *dev, const l2arc_log_blk_phys_t *lb, uint64_t lb_asize); static void l2arc_hdr_restore(const l2arc_log_ent_phys_t *le, l2arc_dev_t *dev); /* L2ARC persistence write I/O routines. */ static void l2arc_log_blk_commit(l2arc_dev_t *dev, zio_t *pio, l2arc_write_callback_t *cb); /* L2ARC persistence auxiliary routines. */ boolean_t l2arc_log_blkptr_valid(l2arc_dev_t *dev, const l2arc_log_blkptr_t *lbp); static boolean_t l2arc_log_blk_insert(l2arc_dev_t *dev, const arc_buf_hdr_t *ab); boolean_t l2arc_range_check_overlap(uint64_t bottom, uint64_t top, uint64_t check); static void l2arc_blk_fetch_done(zio_t *zio); static inline uint64_t l2arc_log_blk_overhead(uint64_t write_sz, l2arc_dev_t *dev); /* * We use Cityhash for this. It's fast, and has good hash properties without * requiring any large static buffers. */ static uint64_t buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth) { return (cityhash4(spa, dva->dva_word[0], dva->dva_word[1], birth)); } #define HDR_EMPTY(hdr) \ ((hdr)->b_dva.dva_word[0] == 0 && \ (hdr)->b_dva.dva_word[1] == 0) #define HDR_EMPTY_OR_LOCKED(hdr) \ (HDR_EMPTY(hdr) || MUTEX_HELD(HDR_LOCK(hdr))) #define HDR_EQUAL(spa, dva, birth, hdr) \ ((hdr)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \ ((hdr)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \ ((hdr)->b_birth == birth) && ((hdr)->b_spa == spa) static void buf_discard_identity(arc_buf_hdr_t *hdr) { hdr->b_dva.dva_word[0] = 0; hdr->b_dva.dva_word[1] = 0; hdr->b_birth = 0; } static arc_buf_hdr_t * buf_hash_find(uint64_t spa, const blkptr_t *bp, kmutex_t **lockp) { const dva_t *dva = BP_IDENTITY(bp); uint64_t birth = BP_PHYSICAL_BIRTH(bp); uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); kmutex_t *hash_lock = BUF_HASH_LOCK(idx); arc_buf_hdr_t *hdr; mutex_enter(hash_lock); for (hdr = buf_hash_table.ht_table[idx]; hdr != NULL; hdr = hdr->b_hash_next) { if (HDR_EQUAL(spa, dva, birth, hdr)) { *lockp = hash_lock; return (hdr); } } mutex_exit(hash_lock); *lockp = NULL; return (NULL); } /* * Insert an entry into the hash table. If there is already an element * equal to elem in the hash table, then the already existing element * will be returned and the new element will not be inserted. * Otherwise returns NULL. * If lockp == NULL, the caller is assumed to already hold the hash lock. */ static arc_buf_hdr_t * buf_hash_insert(arc_buf_hdr_t *hdr, kmutex_t **lockp) { uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth); kmutex_t *hash_lock = BUF_HASH_LOCK(idx); arc_buf_hdr_t *fhdr; uint32_t i; ASSERT(!DVA_IS_EMPTY(&hdr->b_dva)); ASSERT(hdr->b_birth != 0); ASSERT(!HDR_IN_HASH_TABLE(hdr)); if (lockp != NULL) { *lockp = hash_lock; mutex_enter(hash_lock); } else { ASSERT(MUTEX_HELD(hash_lock)); } for (fhdr = buf_hash_table.ht_table[idx], i = 0; fhdr != NULL; fhdr = fhdr->b_hash_next, i++) { if (HDR_EQUAL(hdr->b_spa, &hdr->b_dva, hdr->b_birth, fhdr)) return (fhdr); } hdr->b_hash_next = buf_hash_table.ht_table[idx]; buf_hash_table.ht_table[idx] = hdr; arc_hdr_set_flags(hdr, ARC_FLAG_IN_HASH_TABLE); /* collect some hash table performance data */ if (i > 0) { ARCSTAT_BUMP(arcstat_hash_collisions); if (i == 1) ARCSTAT_BUMP(arcstat_hash_chains); ARCSTAT_MAX(arcstat_hash_chain_max, i); } uint64_t he = atomic_inc_64_nv( &arc_stats.arcstat_hash_elements.value.ui64); ARCSTAT_MAX(arcstat_hash_elements_max, he); return (NULL); } static void buf_hash_remove(arc_buf_hdr_t *hdr) { arc_buf_hdr_t *fhdr, **hdrp; uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth); ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); ASSERT(HDR_IN_HASH_TABLE(hdr)); hdrp = &buf_hash_table.ht_table[idx]; while ((fhdr = *hdrp) != hdr) { ASSERT3P(fhdr, !=, NULL); hdrp = &fhdr->b_hash_next; } *hdrp = hdr->b_hash_next; hdr->b_hash_next = NULL; arc_hdr_clear_flags(hdr, ARC_FLAG_IN_HASH_TABLE); /* collect some hash table performance data */ atomic_dec_64(&arc_stats.arcstat_hash_elements.value.ui64); if (buf_hash_table.ht_table[idx] && buf_hash_table.ht_table[idx]->b_hash_next == NULL) ARCSTAT_BUMPDOWN(arcstat_hash_chains); } /* * Global data structures and functions for the buf kmem cache. */ static kmem_cache_t *hdr_full_cache; static kmem_cache_t *hdr_full_crypt_cache; static kmem_cache_t *hdr_l2only_cache; static kmem_cache_t *buf_cache; static void buf_fini(void) { #if defined(_KERNEL) /* * Large allocations which do not require contiguous pages * should be using vmem_free() in the linux kernel\ */ vmem_free(buf_hash_table.ht_table, (buf_hash_table.ht_mask + 1) * sizeof (void *)); #else kmem_free(buf_hash_table.ht_table, (buf_hash_table.ht_mask + 1) * sizeof (void *)); #endif for (int i = 0; i < BUF_LOCKS; i++) mutex_destroy(BUF_HASH_LOCK(i)); kmem_cache_destroy(hdr_full_cache); kmem_cache_destroy(hdr_full_crypt_cache); kmem_cache_destroy(hdr_l2only_cache); kmem_cache_destroy(buf_cache); } /* * Constructor callback - called when the cache is empty * and a new buf is requested. */ static int hdr_full_cons(void *vbuf, void *unused, int kmflag) { (void) unused, (void) kmflag; arc_buf_hdr_t *hdr = vbuf; memset(hdr, 0, HDR_FULL_SIZE); hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; cv_init(&hdr->b_l1hdr.b_cv, NULL, CV_DEFAULT, NULL); zfs_refcount_create(&hdr->b_l1hdr.b_refcnt); mutex_init(&hdr->b_l1hdr.b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); list_link_init(&hdr->b_l1hdr.b_arc_node); list_link_init(&hdr->b_l2hdr.b_l2node); multilist_link_init(&hdr->b_l1hdr.b_arc_node); arc_space_consume(HDR_FULL_SIZE, ARC_SPACE_HDRS); return (0); } static int hdr_full_crypt_cons(void *vbuf, void *unused, int kmflag) { (void) unused; arc_buf_hdr_t *hdr = vbuf; hdr_full_cons(vbuf, unused, kmflag); memset(&hdr->b_crypt_hdr, 0, sizeof (hdr->b_crypt_hdr)); arc_space_consume(sizeof (hdr->b_crypt_hdr), ARC_SPACE_HDRS); return (0); } static int hdr_l2only_cons(void *vbuf, void *unused, int kmflag) { (void) unused, (void) kmflag; arc_buf_hdr_t *hdr = vbuf; memset(hdr, 0, HDR_L2ONLY_SIZE); arc_space_consume(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS); return (0); } static int buf_cons(void *vbuf, void *unused, int kmflag) { (void) unused, (void) kmflag; arc_buf_t *buf = vbuf; memset(buf, 0, sizeof (arc_buf_t)); mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL); arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); return (0); } /* * Destructor callback - called when a cached buf is * no longer required. */ static void hdr_full_dest(void *vbuf, void *unused) { (void) unused; arc_buf_hdr_t *hdr = vbuf; ASSERT(HDR_EMPTY(hdr)); cv_destroy(&hdr->b_l1hdr.b_cv); zfs_refcount_destroy(&hdr->b_l1hdr.b_refcnt); mutex_destroy(&hdr->b_l1hdr.b_freeze_lock); ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); arc_space_return(HDR_FULL_SIZE, ARC_SPACE_HDRS); } static void hdr_full_crypt_dest(void *vbuf, void *unused) { (void) vbuf, (void) unused; hdr_full_dest(vbuf, unused); arc_space_return(sizeof (((arc_buf_hdr_t *)NULL)->b_crypt_hdr), ARC_SPACE_HDRS); } static void hdr_l2only_dest(void *vbuf, void *unused) { (void) unused; arc_buf_hdr_t *hdr = vbuf; ASSERT(HDR_EMPTY(hdr)); arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS); } static void buf_dest(void *vbuf, void *unused) { (void) unused; arc_buf_t *buf = vbuf; mutex_destroy(&buf->b_evict_lock); arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); } static void buf_init(void) { uint64_t *ct = NULL; uint64_t hsize = 1ULL << 12; int i, j; /* * The hash table is big enough to fill all of physical memory * with an average block size of zfs_arc_average_blocksize (default 8K). * By default, the table will take up * totalmem * sizeof(void*) / 8K (1MB per GB with 8-byte pointers). */ while (hsize * zfs_arc_average_blocksize < arc_all_memory()) hsize <<= 1; retry: buf_hash_table.ht_mask = hsize - 1; #if defined(_KERNEL) /* * Large allocations which do not require contiguous pages * should be using vmem_alloc() in the linux kernel */ buf_hash_table.ht_table = vmem_zalloc(hsize * sizeof (void*), KM_SLEEP); #else buf_hash_table.ht_table = kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); #endif if (buf_hash_table.ht_table == NULL) { ASSERT(hsize > (1ULL << 8)); hsize >>= 1; goto retry; } hdr_full_cache = kmem_cache_create("arc_buf_hdr_t_full", HDR_FULL_SIZE, 0, hdr_full_cons, hdr_full_dest, NULL, NULL, NULL, 0); hdr_full_crypt_cache = kmem_cache_create("arc_buf_hdr_t_full_crypt", HDR_FULL_CRYPT_SIZE, 0, hdr_full_crypt_cons, hdr_full_crypt_dest, NULL, NULL, NULL, 0); hdr_l2only_cache = kmem_cache_create("arc_buf_hdr_t_l2only", HDR_L2ONLY_SIZE, 0, hdr_l2only_cons, hdr_l2only_dest, NULL, NULL, NULL, 0); buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); for (i = 0; i < 256; i++) for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); for (i = 0; i < BUF_LOCKS; i++) mutex_init(BUF_HASH_LOCK(i), NULL, MUTEX_DEFAULT, NULL); } #define ARC_MINTIME (hz>>4) /* 62 ms */ /* * This is the size that the buf occupies in memory. If the buf is compressed, * it will correspond to the compressed size. You should use this method of * getting the buf size unless you explicitly need the logical size. */ uint64_t arc_buf_size(arc_buf_t *buf) { return (ARC_BUF_COMPRESSED(buf) ? HDR_GET_PSIZE(buf->b_hdr) : HDR_GET_LSIZE(buf->b_hdr)); } uint64_t arc_buf_lsize(arc_buf_t *buf) { return (HDR_GET_LSIZE(buf->b_hdr)); } /* * This function will return B_TRUE if the buffer is encrypted in memory. * This buffer can be decrypted by calling arc_untransform(). */ boolean_t arc_is_encrypted(arc_buf_t *buf) { return (ARC_BUF_ENCRYPTED(buf) != 0); } /* * Returns B_TRUE if the buffer represents data that has not had its MAC * verified yet. */ boolean_t arc_is_unauthenticated(arc_buf_t *buf) { return (HDR_NOAUTH(buf->b_hdr) != 0); } void arc_get_raw_params(arc_buf_t *buf, boolean_t *byteorder, uint8_t *salt, uint8_t *iv, uint8_t *mac) { arc_buf_hdr_t *hdr = buf->b_hdr; ASSERT(HDR_PROTECTED(hdr)); memcpy(salt, hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN); memcpy(iv, hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN); memcpy(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN); *byteorder = (hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS) ? ZFS_HOST_BYTEORDER : !ZFS_HOST_BYTEORDER; } /* * Indicates how this buffer is compressed in memory. If it is not compressed * the value will be ZIO_COMPRESS_OFF. It can be made normally readable with * arc_untransform() as long as it is also unencrypted. */ enum zio_compress arc_get_compression(arc_buf_t *buf) { return (ARC_BUF_COMPRESSED(buf) ? HDR_GET_COMPRESS(buf->b_hdr) : ZIO_COMPRESS_OFF); } /* * Return the compression algorithm used to store this data in the ARC. If ARC * compression is enabled or this is an encrypted block, this will be the same * as what's used to store it on-disk. Otherwise, this will be ZIO_COMPRESS_OFF. */ static inline enum zio_compress arc_hdr_get_compress(arc_buf_hdr_t *hdr) { return (HDR_COMPRESSION_ENABLED(hdr) ? HDR_GET_COMPRESS(hdr) : ZIO_COMPRESS_OFF); } uint8_t arc_get_complevel(arc_buf_t *buf) { return (buf->b_hdr->b_complevel); } static inline boolean_t arc_buf_is_shared(arc_buf_t *buf) { boolean_t shared = (buf->b_data != NULL && buf->b_hdr->b_l1hdr.b_pabd != NULL && abd_is_linear(buf->b_hdr->b_l1hdr.b_pabd) && buf->b_data == abd_to_buf(buf->b_hdr->b_l1hdr.b_pabd)); IMPLY(shared, HDR_SHARED_DATA(buf->b_hdr)); IMPLY(shared, ARC_BUF_SHARED(buf)); IMPLY(shared, ARC_BUF_COMPRESSED(buf) || ARC_BUF_LAST(buf)); /* * It would be nice to assert arc_can_share() too, but the "hdr isn't * already being shared" requirement prevents us from doing that. */ return (shared); } /* * Free the checksum associated with this header. If there is no checksum, this * is a no-op. */ static inline void arc_cksum_free(arc_buf_hdr_t *hdr) { ASSERT(HDR_HAS_L1HDR(hdr)); mutex_enter(&hdr->b_l1hdr.b_freeze_lock); if (hdr->b_l1hdr.b_freeze_cksum != NULL) { kmem_free(hdr->b_l1hdr.b_freeze_cksum, sizeof (zio_cksum_t)); hdr->b_l1hdr.b_freeze_cksum = NULL; } mutex_exit(&hdr->b_l1hdr.b_freeze_lock); } /* * Return true iff at least one of the bufs on hdr is not compressed. * Encrypted buffers count as compressed. */ static boolean_t arc_hdr_has_uncompressed_buf(arc_buf_hdr_t *hdr) { ASSERT(hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY_OR_LOCKED(hdr)); for (arc_buf_t *b = hdr->b_l1hdr.b_buf; b != NULL; b = b->b_next) { if (!ARC_BUF_COMPRESSED(b)) { return (B_TRUE); } } return (B_FALSE); } /* * If we've turned on the ZFS_DEBUG_MODIFY flag, verify that the buf's data * matches the checksum that is stored in the hdr. If there is no checksum, * or if the buf is compressed, this is a no-op. */ static void arc_cksum_verify(arc_buf_t *buf) { arc_buf_hdr_t *hdr = buf->b_hdr; zio_cksum_t zc; if (!(zfs_flags & ZFS_DEBUG_MODIFY)) return; if (ARC_BUF_COMPRESSED(buf)) return; ASSERT(HDR_HAS_L1HDR(hdr)); mutex_enter(&hdr->b_l1hdr.b_freeze_lock); if (hdr->b_l1hdr.b_freeze_cksum == NULL || HDR_IO_ERROR(hdr)) { mutex_exit(&hdr->b_l1hdr.b_freeze_lock); return; } fletcher_2_native(buf->b_data, arc_buf_size(buf), NULL, &zc); if (!ZIO_CHECKSUM_EQUAL(*hdr->b_l1hdr.b_freeze_cksum, zc)) panic("buffer modified while frozen!"); mutex_exit(&hdr->b_l1hdr.b_freeze_lock); } /* * This function makes the assumption that data stored in the L2ARC * will be transformed exactly as it is in the main pool. Because of * this we can verify the checksum against the reading process's bp. */ static boolean_t arc_cksum_is_equal(arc_buf_hdr_t *hdr, zio_t *zio) { ASSERT(!BP_IS_EMBEDDED(zio->io_bp)); VERIFY3U(BP_GET_PSIZE(zio->io_bp), ==, HDR_GET_PSIZE(hdr)); /* * Block pointers always store the checksum for the logical data. * If the block pointer has the gang bit set, then the checksum * it represents is for the reconstituted data and not for an * individual gang member. The zio pipeline, however, must be able to * determine the checksum of each of the gang constituents so it * treats the checksum comparison differently than what we need * for l2arc blocks. This prevents us from using the * zio_checksum_error() interface directly. Instead we must call the * zio_checksum_error_impl() so that we can ensure the checksum is * generated using the correct checksum algorithm and accounts for the * logical I/O size and not just a gang fragment. */ return (zio_checksum_error_impl(zio->io_spa, zio->io_bp, BP_GET_CHECKSUM(zio->io_bp), zio->io_abd, zio->io_size, zio->io_offset, NULL) == 0); } /* * Given a buf full of data, if ZFS_DEBUG_MODIFY is enabled this computes a * checksum and attaches it to the buf's hdr so that we can ensure that the buf * isn't modified later on. If buf is compressed or there is already a checksum * on the hdr, this is a no-op (we only checksum uncompressed bufs). */ static void arc_cksum_compute(arc_buf_t *buf) { arc_buf_hdr_t *hdr = buf->b_hdr; if (!(zfs_flags & ZFS_DEBUG_MODIFY)) return; ASSERT(HDR_HAS_L1HDR(hdr)); mutex_enter(&buf->b_hdr->b_l1hdr.b_freeze_lock); if (hdr->b_l1hdr.b_freeze_cksum != NULL || ARC_BUF_COMPRESSED(buf)) { mutex_exit(&hdr->b_l1hdr.b_freeze_lock); return; } ASSERT(!ARC_BUF_ENCRYPTED(buf)); ASSERT(!ARC_BUF_COMPRESSED(buf)); hdr->b_l1hdr.b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), KM_SLEEP); fletcher_2_native(buf->b_data, arc_buf_size(buf), NULL, hdr->b_l1hdr.b_freeze_cksum); mutex_exit(&hdr->b_l1hdr.b_freeze_lock); arc_buf_watch(buf); } #ifndef _KERNEL void arc_buf_sigsegv(int sig, siginfo_t *si, void *unused) { (void) sig, (void) unused; panic("Got SIGSEGV at address: 0x%lx\n", (long)si->si_addr); } #endif static void arc_buf_unwatch(arc_buf_t *buf) { #ifndef _KERNEL if (arc_watch) { ASSERT0(mprotect(buf->b_data, arc_buf_size(buf), PROT_READ | PROT_WRITE)); } #else (void) buf; #endif } static void arc_buf_watch(arc_buf_t *buf) { #ifndef _KERNEL if (arc_watch) ASSERT0(mprotect(buf->b_data, arc_buf_size(buf), PROT_READ)); #else (void) buf; #endif } static arc_buf_contents_t arc_buf_type(arc_buf_hdr_t *hdr) { arc_buf_contents_t type; if (HDR_ISTYPE_METADATA(hdr)) { type = ARC_BUFC_METADATA; } else { type = ARC_BUFC_DATA; } VERIFY3U(hdr->b_type, ==, type); return (type); } boolean_t arc_is_metadata(arc_buf_t *buf) { return (HDR_ISTYPE_METADATA(buf->b_hdr) != 0); } static uint32_t arc_bufc_to_flags(arc_buf_contents_t type) { switch (type) { case ARC_BUFC_DATA: /* metadata field is 0 if buffer contains normal data */ return (0); case ARC_BUFC_METADATA: return (ARC_FLAG_BUFC_METADATA); default: break; } panic("undefined ARC buffer type!"); return ((uint32_t)-1); } void arc_buf_thaw(arc_buf_t *buf) { arc_buf_hdr_t *hdr = buf->b_hdr; ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); ASSERT(!HDR_IO_IN_PROGRESS(hdr)); arc_cksum_verify(buf); /* * Compressed buffers do not manipulate the b_freeze_cksum. */ if (ARC_BUF_COMPRESSED(buf)) return; ASSERT(HDR_HAS_L1HDR(hdr)); arc_cksum_free(hdr); arc_buf_unwatch(buf); } void arc_buf_freeze(arc_buf_t *buf) { if (!(zfs_flags & ZFS_DEBUG_MODIFY)) return; if (ARC_BUF_COMPRESSED(buf)) return; ASSERT(HDR_HAS_L1HDR(buf->b_hdr)); arc_cksum_compute(buf); } /* * The arc_buf_hdr_t's b_flags should never be modified directly. Instead, * the following functions should be used to ensure that the flags are * updated in a thread-safe way. When manipulating the flags either * the hash_lock must be held or the hdr must be undiscoverable. This * ensures that we're not racing with any other threads when updating * the flags. */ static inline void arc_hdr_set_flags(arc_buf_hdr_t *hdr, arc_flags_t flags) { ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); hdr->b_flags |= flags; } static inline void arc_hdr_clear_flags(arc_buf_hdr_t *hdr, arc_flags_t flags) { ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); hdr->b_flags &= ~flags; } /* * Setting the compression bits in the arc_buf_hdr_t's b_flags is * done in a special way since we have to clear and set bits * at the same time. Consumers that wish to set the compression bits * must use this function to ensure that the flags are updated in * thread-safe manner. */ static void arc_hdr_set_compress(arc_buf_hdr_t *hdr, enum zio_compress cmp) { ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); /* * Holes and embedded blocks will always have a psize = 0 so * we ignore the compression of the blkptr and set the * want to uncompress them. Mark them as uncompressed. */ if (!zfs_compressed_arc_enabled || HDR_GET_PSIZE(hdr) == 0) { arc_hdr_clear_flags(hdr, ARC_FLAG_COMPRESSED_ARC); ASSERT(!HDR_COMPRESSION_ENABLED(hdr)); } else { arc_hdr_set_flags(hdr, ARC_FLAG_COMPRESSED_ARC); ASSERT(HDR_COMPRESSION_ENABLED(hdr)); } HDR_SET_COMPRESS(hdr, cmp); ASSERT3U(HDR_GET_COMPRESS(hdr), ==, cmp); } /* * Looks for another buf on the same hdr which has the data decompressed, copies * from it, and returns true. If no such buf exists, returns false. */ static boolean_t arc_buf_try_copy_decompressed_data(arc_buf_t *buf) { arc_buf_hdr_t *hdr = buf->b_hdr; boolean_t copied = B_FALSE; ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT3P(buf->b_data, !=, NULL); ASSERT(!ARC_BUF_COMPRESSED(buf)); for (arc_buf_t *from = hdr->b_l1hdr.b_buf; from != NULL; from = from->b_next) { /* can't use our own data buffer */ if (from == buf) { continue; } if (!ARC_BUF_COMPRESSED(from)) { memcpy(buf->b_data, from->b_data, arc_buf_size(buf)); copied = B_TRUE; break; } } /* * There were no decompressed bufs, so there should not be a * checksum on the hdr either. */ if (zfs_flags & ZFS_DEBUG_MODIFY) EQUIV(!copied, hdr->b_l1hdr.b_freeze_cksum == NULL); return (copied); } /* * Allocates an ARC buf header that's in an evicted & L2-cached state. * This is used during l2arc reconstruction to make empty ARC buffers * which circumvent the regular disk->arc->l2arc path and instead come * into being in the reverse order, i.e. l2arc->arc. */ static arc_buf_hdr_t * arc_buf_alloc_l2only(size_t size, arc_buf_contents_t type, l2arc_dev_t *dev, dva_t dva, uint64_t daddr, int32_t psize, uint64_t birth, enum zio_compress compress, uint8_t complevel, boolean_t protected, boolean_t prefetch, arc_state_type_t arcs_state) { arc_buf_hdr_t *hdr; ASSERT(size != 0); hdr = kmem_cache_alloc(hdr_l2only_cache, KM_SLEEP); hdr->b_birth = birth; hdr->b_type = type; hdr->b_flags = 0; arc_hdr_set_flags(hdr, arc_bufc_to_flags(type) | ARC_FLAG_HAS_L2HDR); HDR_SET_LSIZE(hdr, size); HDR_SET_PSIZE(hdr, psize); arc_hdr_set_compress(hdr, compress); hdr->b_complevel = complevel; if (protected) arc_hdr_set_flags(hdr, ARC_FLAG_PROTECTED); if (prefetch) arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH); hdr->b_spa = spa_load_guid(dev->l2ad_vdev->vdev_spa); hdr->b_dva = dva; hdr->b_l2hdr.b_dev = dev; hdr->b_l2hdr.b_daddr = daddr; hdr->b_l2hdr.b_arcs_state = arcs_state; return (hdr); } /* * Return the size of the block, b_pabd, that is stored in the arc_buf_hdr_t. */ static uint64_t arc_hdr_size(arc_buf_hdr_t *hdr) { uint64_t size; if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF && HDR_GET_PSIZE(hdr) > 0) { size = HDR_GET_PSIZE(hdr); } else { ASSERT3U(HDR_GET_LSIZE(hdr), !=, 0); size = HDR_GET_LSIZE(hdr); } return (size); } static int arc_hdr_authenticate(arc_buf_hdr_t *hdr, spa_t *spa, uint64_t dsobj) { int ret; uint64_t csize; uint64_t lsize = HDR_GET_LSIZE(hdr); uint64_t psize = HDR_GET_PSIZE(hdr); void *tmpbuf = NULL; abd_t *abd = hdr->b_l1hdr.b_pabd; ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); ASSERT(HDR_AUTHENTICATED(hdr)); ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); /* * The MAC is calculated on the compressed data that is stored on disk. * However, if compressed arc is disabled we will only have the * decompressed data available to us now. Compress it into a temporary * abd so we can verify the MAC. The performance overhead of this will * be relatively low, since most objects in an encrypted objset will * be encrypted (instead of authenticated) anyway. */ if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr)) { tmpbuf = zio_buf_alloc(lsize); abd = abd_get_from_buf(tmpbuf, lsize); abd_take_ownership_of_buf(abd, B_TRUE); csize = zio_compress_data(HDR_GET_COMPRESS(hdr), hdr->b_l1hdr.b_pabd, tmpbuf, lsize, hdr->b_complevel); ASSERT3U(csize, <=, psize); abd_zero_off(abd, csize, psize - csize); } /* * Authentication is best effort. We authenticate whenever the key is * available. If we succeed we clear ARC_FLAG_NOAUTH. */ if (hdr->b_crypt_hdr.b_ot == DMU_OT_OBJSET) { ASSERT3U(HDR_GET_COMPRESS(hdr), ==, ZIO_COMPRESS_OFF); ASSERT3U(lsize, ==, psize); ret = spa_do_crypt_objset_mac_abd(B_FALSE, spa, dsobj, abd, psize, hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS); } else { ret = spa_do_crypt_mac_abd(B_FALSE, spa, dsobj, abd, psize, hdr->b_crypt_hdr.b_mac); } if (ret == 0) arc_hdr_clear_flags(hdr, ARC_FLAG_NOAUTH); else if (ret != ENOENT) goto error; if (tmpbuf != NULL) abd_free(abd); return (0); error: if (tmpbuf != NULL) abd_free(abd); return (ret); } /* * This function will take a header that only has raw encrypted data in * b_crypt_hdr.b_rabd and decrypt it into a new buffer which is stored in * b_l1hdr.b_pabd. If designated in the header flags, this function will * also decompress the data. */ static int arc_hdr_decrypt(arc_buf_hdr_t *hdr, spa_t *spa, const zbookmark_phys_t *zb) { int ret; abd_t *cabd = NULL; void *tmp = NULL; boolean_t no_crypt = B_FALSE; boolean_t bswap = (hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS); ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); ASSERT(HDR_ENCRYPTED(hdr)); arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT); ret = spa_do_crypt_abd(B_FALSE, spa, zb, hdr->b_crypt_hdr.b_ot, B_FALSE, bswap, hdr->b_crypt_hdr.b_salt, hdr->b_crypt_hdr.b_iv, hdr->b_crypt_hdr.b_mac, HDR_GET_PSIZE(hdr), hdr->b_l1hdr.b_pabd, hdr->b_crypt_hdr.b_rabd, &no_crypt); if (ret != 0) goto error; if (no_crypt) { abd_copy(hdr->b_l1hdr.b_pabd, hdr->b_crypt_hdr.b_rabd, HDR_GET_PSIZE(hdr)); } /* * If this header has disabled arc compression but the b_pabd is * compressed after decrypting it, we need to decompress the newly * decrypted data. */ if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr)) { /* * We want to make sure that we are correctly honoring the * zfs_abd_scatter_enabled setting, so we allocate an abd here * and then loan a buffer from it, rather than allocating a * linear buffer and wrapping it in an abd later. */ cabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, ARC_HDR_DO_ADAPT); tmp = abd_borrow_buf(cabd, arc_hdr_size(hdr)); ret = zio_decompress_data(HDR_GET_COMPRESS(hdr), hdr->b_l1hdr.b_pabd, tmp, HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr), &hdr->b_complevel); if (ret != 0) { abd_return_buf(cabd, tmp, arc_hdr_size(hdr)); goto error; } abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr)); arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, arc_hdr_size(hdr), hdr); hdr->b_l1hdr.b_pabd = cabd; } return (0); error: arc_hdr_free_abd(hdr, B_FALSE); if (cabd != NULL) arc_free_data_buf(hdr, cabd, arc_hdr_size(hdr), hdr); return (ret); } /* * This function is called during arc_buf_fill() to prepare the header's * abd plaintext pointer for use. This involves authenticated protected * data and decrypting encrypted data into the plaintext abd. */ static int arc_fill_hdr_crypt(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, spa_t *spa, const zbookmark_phys_t *zb, boolean_t noauth) { int ret; ASSERT(HDR_PROTECTED(hdr)); if (hash_lock != NULL) mutex_enter(hash_lock); if (HDR_NOAUTH(hdr) && !noauth) { /* * The caller requested authenticated data but our data has * not been authenticated yet. Verify the MAC now if we can. */ ret = arc_hdr_authenticate(hdr, spa, zb->zb_objset); if (ret != 0) goto error; } else if (HDR_HAS_RABD(hdr) && hdr->b_l1hdr.b_pabd == NULL) { /* * If we only have the encrypted version of the data, but the * unencrypted version was requested we take this opportunity * to store the decrypted version in the header for future use. */ ret = arc_hdr_decrypt(hdr, spa, zb); if (ret != 0) goto error; } ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); if (hash_lock != NULL) mutex_exit(hash_lock); return (0); error: if (hash_lock != NULL) mutex_exit(hash_lock); return (ret); } /* * This function is used by the dbuf code to decrypt bonus buffers in place. * The dbuf code itself doesn't have any locking for decrypting a shared dnode * block, so we use the hash lock here to protect against concurrent calls to * arc_buf_fill(). */ static void arc_buf_untransform_in_place(arc_buf_t *buf) { arc_buf_hdr_t *hdr = buf->b_hdr; ASSERT(HDR_ENCRYPTED(hdr)); ASSERT3U(hdr->b_crypt_hdr.b_ot, ==, DMU_OT_DNODE); ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); zio_crypt_copy_dnode_bonus(hdr->b_l1hdr.b_pabd, buf->b_data, arc_buf_size(buf)); buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED; buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; hdr->b_crypt_hdr.b_ebufcnt -= 1; } /* * Given a buf that has a data buffer attached to it, this function will * efficiently fill the buf with data of the specified compression setting from * the hdr and update the hdr's b_freeze_cksum if necessary. If the buf and hdr * are already sharing a data buf, no copy is performed. * * If the buf is marked as compressed but uncompressed data was requested, this * will allocate a new data buffer for the buf, remove that flag, and fill the * buf with uncompressed data. You can't request a compressed buf on a hdr with * uncompressed data, and (since we haven't added support for it yet) if you * want compressed data your buf must already be marked as compressed and have * the correct-sized data buffer. */ static int arc_buf_fill(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb, arc_fill_flags_t flags) { int error = 0; arc_buf_hdr_t *hdr = buf->b_hdr; boolean_t hdr_compressed = (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF); boolean_t compressed = (flags & ARC_FILL_COMPRESSED) != 0; boolean_t encrypted = (flags & ARC_FILL_ENCRYPTED) != 0; dmu_object_byteswap_t bswap = hdr->b_l1hdr.b_byteswap; kmutex_t *hash_lock = (flags & ARC_FILL_LOCKED) ? NULL : HDR_LOCK(hdr); ASSERT3P(buf->b_data, !=, NULL); IMPLY(compressed, hdr_compressed || ARC_BUF_ENCRYPTED(buf)); IMPLY(compressed, ARC_BUF_COMPRESSED(buf)); IMPLY(encrypted, HDR_ENCRYPTED(hdr)); IMPLY(encrypted, ARC_BUF_ENCRYPTED(buf)); IMPLY(encrypted, ARC_BUF_COMPRESSED(buf)); IMPLY(encrypted, !ARC_BUF_SHARED(buf)); /* * If the caller wanted encrypted data we just need to copy it from * b_rabd and potentially byteswap it. We won't be able to do any * further transforms on it. */ if (encrypted) { ASSERT(HDR_HAS_RABD(hdr)); abd_copy_to_buf(buf->b_data, hdr->b_crypt_hdr.b_rabd, HDR_GET_PSIZE(hdr)); goto byteswap; } /* * Adjust encrypted and authenticated headers to accommodate * the request if needed. Dnode blocks (ARC_FILL_IN_PLACE) are * allowed to fail decryption due to keys not being loaded * without being marked as an IO error. */ if (HDR_PROTECTED(hdr)) { error = arc_fill_hdr_crypt(hdr, hash_lock, spa, zb, !!(flags & ARC_FILL_NOAUTH)); if (error == EACCES && (flags & ARC_FILL_IN_PLACE) != 0) { return (error); } else if (error != 0) { if (hash_lock != NULL) mutex_enter(hash_lock); arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR); if (hash_lock != NULL) mutex_exit(hash_lock); return (error); } } /* * There is a special case here for dnode blocks which are * decrypting their bonus buffers. These blocks may request to * be decrypted in-place. This is necessary because there may * be many dnodes pointing into this buffer and there is * currently no method to synchronize replacing the backing * b_data buffer and updating all of the pointers. Here we use * the hash lock to ensure there are no races. If the need * arises for other types to be decrypted in-place, they must * add handling here as well. */ if ((flags & ARC_FILL_IN_PLACE) != 0) { ASSERT(!hdr_compressed); ASSERT(!compressed); ASSERT(!encrypted); if (HDR_ENCRYPTED(hdr) && ARC_BUF_ENCRYPTED(buf)) { ASSERT3U(hdr->b_crypt_hdr.b_ot, ==, DMU_OT_DNODE); if (hash_lock != NULL) mutex_enter(hash_lock); arc_buf_untransform_in_place(buf); if (hash_lock != NULL) mutex_exit(hash_lock); /* Compute the hdr's checksum if necessary */ arc_cksum_compute(buf); } return (0); } if (hdr_compressed == compressed) { if (!arc_buf_is_shared(buf)) { abd_copy_to_buf(buf->b_data, hdr->b_l1hdr.b_pabd, arc_buf_size(buf)); } } else { ASSERT(hdr_compressed); ASSERT(!compressed); /* * If the buf is sharing its data with the hdr, unlink it and * allocate a new data buffer for the buf. */ if (arc_buf_is_shared(buf)) { ASSERT(ARC_BUF_COMPRESSED(buf)); /* We need to give the buf its own b_data */ buf->b_flags &= ~ARC_BUF_FLAG_SHARED; buf->b_data = arc_get_data_buf(hdr, HDR_GET_LSIZE(hdr), buf); arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA); /* Previously overhead was 0; just add new overhead */ ARCSTAT_INCR(arcstat_overhead_size, HDR_GET_LSIZE(hdr)); } else if (ARC_BUF_COMPRESSED(buf)) { /* We need to reallocate the buf's b_data */ arc_free_data_buf(hdr, buf->b_data, HDR_GET_PSIZE(hdr), buf); buf->b_data = arc_get_data_buf(hdr, HDR_GET_LSIZE(hdr), buf); /* We increased the size of b_data; update overhead */ ARCSTAT_INCR(arcstat_overhead_size, HDR_GET_LSIZE(hdr) - HDR_GET_PSIZE(hdr)); } /* * Regardless of the buf's previous compression settings, it * should not be compressed at the end of this function. */ buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; /* * Try copying the data from another buf which already has a * decompressed version. If that's not possible, it's time to * bite the bullet and decompress the data from the hdr. */ if (arc_buf_try_copy_decompressed_data(buf)) { /* Skip byteswapping and checksumming (already done) */ return (0); } else { error = zio_decompress_data(HDR_GET_COMPRESS(hdr), hdr->b_l1hdr.b_pabd, buf->b_data, HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr), &hdr->b_complevel); /* * Absent hardware errors or software bugs, this should * be impossible, but log it anyway so we can debug it. */ if (error != 0) { zfs_dbgmsg( "hdr %px, compress %d, psize %d, lsize %d", hdr, arc_hdr_get_compress(hdr), HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr)); if (hash_lock != NULL) mutex_enter(hash_lock); arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR); if (hash_lock != NULL) mutex_exit(hash_lock); return (SET_ERROR(EIO)); } } } byteswap: /* Byteswap the buf's data if necessary */ if (bswap != DMU_BSWAP_NUMFUNCS) { ASSERT(!HDR_SHARED_DATA(hdr)); ASSERT3U(bswap, <, DMU_BSWAP_NUMFUNCS); dmu_ot_byteswap[bswap].ob_func(buf->b_data, HDR_GET_LSIZE(hdr)); } /* Compute the hdr's checksum if necessary */ arc_cksum_compute(buf); return (0); } /* * If this function is being called to decrypt an encrypted buffer or verify an * authenticated one, the key must be loaded and a mapping must be made * available in the keystore via spa_keystore_create_mapping() or one of its * callers. */ int arc_untransform(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb, boolean_t in_place) { int ret; arc_fill_flags_t flags = 0; if (in_place) flags |= ARC_FILL_IN_PLACE; ret = arc_buf_fill(buf, spa, zb, flags); if (ret == ECKSUM) { /* * Convert authentication and decryption errors to EIO * (and generate an ereport) before leaving the ARC. */ ret = SET_ERROR(EIO); spa_log_error(spa, zb); (void) zfs_ereport_post(FM_EREPORT_ZFS_AUTHENTICATION, spa, NULL, zb, NULL, 0); } return (ret); } /* * Increment the amount of evictable space in the arc_state_t's refcount. * We account for the space used by the hdr and the arc buf individually * so that we can add and remove them from the refcount individually. */ static void arc_evictable_space_increment(arc_buf_hdr_t *hdr, arc_state_t *state) { arc_buf_contents_t type = arc_buf_type(hdr); ASSERT(HDR_HAS_L1HDR(hdr)); if (GHOST_STATE(state)) { ASSERT0(hdr->b_l1hdr.b_bufcnt); ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); (void) zfs_refcount_add_many(&state->arcs_esize[type], HDR_GET_LSIZE(hdr), hdr); return; } if (hdr->b_l1hdr.b_pabd != NULL) { (void) zfs_refcount_add_many(&state->arcs_esize[type], arc_hdr_size(hdr), hdr); } if (HDR_HAS_RABD(hdr)) { (void) zfs_refcount_add_many(&state->arcs_esize[type], HDR_GET_PSIZE(hdr), hdr); } for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; buf = buf->b_next) { if (arc_buf_is_shared(buf)) continue; (void) zfs_refcount_add_many(&state->arcs_esize[type], arc_buf_size(buf), buf); } } /* * Decrement the amount of evictable space in the arc_state_t's refcount. * We account for the space used by the hdr and the arc buf individually * so that we can add and remove them from the refcount individually. */ static void arc_evictable_space_decrement(arc_buf_hdr_t *hdr, arc_state_t *state) { arc_buf_contents_t type = arc_buf_type(hdr); ASSERT(HDR_HAS_L1HDR(hdr)); if (GHOST_STATE(state)) { ASSERT0(hdr->b_l1hdr.b_bufcnt); ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); (void) zfs_refcount_remove_many(&state->arcs_esize[type], HDR_GET_LSIZE(hdr), hdr); return; } if (hdr->b_l1hdr.b_pabd != NULL) { (void) zfs_refcount_remove_many(&state->arcs_esize[type], arc_hdr_size(hdr), hdr); } if (HDR_HAS_RABD(hdr)) { (void) zfs_refcount_remove_many(&state->arcs_esize[type], HDR_GET_PSIZE(hdr), hdr); } for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; buf = buf->b_next) { if (arc_buf_is_shared(buf)) continue; (void) zfs_refcount_remove_many(&state->arcs_esize[type], arc_buf_size(buf), buf); } } /* * Add a reference to this hdr indicating that someone is actively * referencing that memory. When the refcount transitions from 0 to 1, * we remove it from the respective arc_state_t list to indicate that * it is not evictable. */ static void add_reference(arc_buf_hdr_t *hdr, const void *tag) { arc_state_t *state; ASSERT(HDR_HAS_L1HDR(hdr)); if (!HDR_EMPTY(hdr) && !MUTEX_HELD(HDR_LOCK(hdr))) { ASSERT(hdr->b_l1hdr.b_state == arc_anon); ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); } state = hdr->b_l1hdr.b_state; if ((zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, tag) == 1) && (state != arc_anon)) { /* We don't use the L2-only state list. */ if (state != arc_l2c_only) { multilist_remove(&state->arcs_list[arc_buf_type(hdr)], hdr); arc_evictable_space_decrement(hdr, state); } /* remove the prefetch flag if we get a reference */ if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_decrement_state(hdr); arc_hdr_clear_flags(hdr, ARC_FLAG_PREFETCH); if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_increment_state(hdr); } } /* * Remove a reference from this hdr. When the reference transitions from * 1 to 0 and we're not anonymous, then we add this hdr to the arc_state_t's * list making it eligible for eviction. */ static int remove_reference(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, const void *tag) { int cnt; arc_state_t *state = hdr->b_l1hdr.b_state; ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); ASSERT(!GHOST_STATE(state)); /* * arc_l2c_only counts as a ghost state so we don't need to explicitly * check to prevent usage of the arc_l2c_only list. */ if (((cnt = zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, tag)) == 0) && (state != arc_anon)) { multilist_insert(&state->arcs_list[arc_buf_type(hdr)], hdr); ASSERT3U(hdr->b_l1hdr.b_bufcnt, >, 0); arc_evictable_space_increment(hdr, state); } return (cnt); } /* * Returns detailed information about a specific arc buffer. When the * state_index argument is set the function will calculate the arc header * list position for its arc state. Since this requires a linear traversal * callers are strongly encourage not to do this. However, it can be helpful * for targeted analysis so the functionality is provided. */ void arc_buf_info(arc_buf_t *ab, arc_buf_info_t *abi, int state_index) { (void) state_index; arc_buf_hdr_t *hdr = ab->b_hdr; l1arc_buf_hdr_t *l1hdr = NULL; l2arc_buf_hdr_t *l2hdr = NULL; arc_state_t *state = NULL; memset(abi, 0, sizeof (arc_buf_info_t)); if (hdr == NULL) return; abi->abi_flags = hdr->b_flags; if (HDR_HAS_L1HDR(hdr)) { l1hdr = &hdr->b_l1hdr; state = l1hdr->b_state; } if (HDR_HAS_L2HDR(hdr)) l2hdr = &hdr->b_l2hdr; if (l1hdr) { abi->abi_bufcnt = l1hdr->b_bufcnt; abi->abi_access = l1hdr->b_arc_access; abi->abi_mru_hits = l1hdr->b_mru_hits; abi->abi_mru_ghost_hits = l1hdr->b_mru_ghost_hits; abi->abi_mfu_hits = l1hdr->b_mfu_hits; abi->abi_mfu_ghost_hits = l1hdr->b_mfu_ghost_hits; abi->abi_holds = zfs_refcount_count(&l1hdr->b_refcnt); } if (l2hdr) { abi->abi_l2arc_dattr = l2hdr->b_daddr; abi->abi_l2arc_hits = l2hdr->b_hits; } abi->abi_state_type = state ? state->arcs_state : ARC_STATE_ANON; abi->abi_state_contents = arc_buf_type(hdr); abi->abi_size = arc_hdr_size(hdr); } /* * Move the supplied buffer to the indicated state. The hash lock * for the buffer must be held by the caller. */ static void arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *hdr, kmutex_t *hash_lock) { arc_state_t *old_state; int64_t refcnt; uint32_t bufcnt; boolean_t update_old, update_new; arc_buf_contents_t buftype = arc_buf_type(hdr); /* * We almost always have an L1 hdr here, since we call arc_hdr_realloc() * in arc_read() when bringing a buffer out of the L2ARC. However, the * L1 hdr doesn't always exist when we change state to arc_anon before * destroying a header, in which case reallocating to add the L1 hdr is * pointless. */ if (HDR_HAS_L1HDR(hdr)) { old_state = hdr->b_l1hdr.b_state; refcnt = zfs_refcount_count(&hdr->b_l1hdr.b_refcnt); bufcnt = hdr->b_l1hdr.b_bufcnt; update_old = (bufcnt > 0 || hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); } else { old_state = arc_l2c_only; refcnt = 0; bufcnt = 0; update_old = B_FALSE; } update_new = update_old; ASSERT(MUTEX_HELD(hash_lock)); ASSERT3P(new_state, !=, old_state); ASSERT(!GHOST_STATE(new_state) || bufcnt == 0); ASSERT(old_state != arc_anon || bufcnt <= 1); /* * If this buffer is evictable, transfer it from the * old state list to the new state list. */ if (refcnt == 0) { if (old_state != arc_anon && old_state != arc_l2c_only) { ASSERT(HDR_HAS_L1HDR(hdr)); multilist_remove(&old_state->arcs_list[buftype], hdr); if (GHOST_STATE(old_state)) { ASSERT0(bufcnt); ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); update_old = B_TRUE; } arc_evictable_space_decrement(hdr, old_state); } if (new_state != arc_anon && new_state != arc_l2c_only) { /* * An L1 header always exists here, since if we're * moving to some L1-cached state (i.e. not l2c_only or * anonymous), we realloc the header to add an L1hdr * beforehand. */ ASSERT(HDR_HAS_L1HDR(hdr)); multilist_insert(&new_state->arcs_list[buftype], hdr); if (GHOST_STATE(new_state)) { ASSERT0(bufcnt); ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); update_new = B_TRUE; } arc_evictable_space_increment(hdr, new_state); } } ASSERT(!HDR_EMPTY(hdr)); if (new_state == arc_anon && HDR_IN_HASH_TABLE(hdr)) buf_hash_remove(hdr); /* adjust state sizes (ignore arc_l2c_only) */ if (update_new && new_state != arc_l2c_only) { ASSERT(HDR_HAS_L1HDR(hdr)); if (GHOST_STATE(new_state)) { ASSERT0(bufcnt); /* * When moving a header to a ghost state, we first * remove all arc buffers. Thus, we'll have a * bufcnt of zero, and no arc buffer to use for * the reference. As a result, we use the arc * header pointer for the reference. */ (void) zfs_refcount_add_many(&new_state->arcs_size, HDR_GET_LSIZE(hdr), hdr); ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); } else { uint32_t buffers = 0; /* * Each individual buffer holds a unique reference, * thus we must remove each of these references one * at a time. */ for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; buf = buf->b_next) { ASSERT3U(bufcnt, !=, 0); buffers++; /* * When the arc_buf_t is sharing the data * block with the hdr, the owner of the * reference belongs to the hdr. Only * add to the refcount if the arc_buf_t is * not shared. */ if (arc_buf_is_shared(buf)) continue; (void) zfs_refcount_add_many( &new_state->arcs_size, arc_buf_size(buf), buf); } ASSERT3U(bufcnt, ==, buffers); if (hdr->b_l1hdr.b_pabd != NULL) { (void) zfs_refcount_add_many( &new_state->arcs_size, arc_hdr_size(hdr), hdr); } if (HDR_HAS_RABD(hdr)) { (void) zfs_refcount_add_many( &new_state->arcs_size, HDR_GET_PSIZE(hdr), hdr); } } } if (update_old && old_state != arc_l2c_only) { ASSERT(HDR_HAS_L1HDR(hdr)); if (GHOST_STATE(old_state)) { ASSERT0(bufcnt); ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); /* * When moving a header off of a ghost state, * the header will not contain any arc buffers. * We use the arc header pointer for the reference * which is exactly what we did when we put the * header on the ghost state. */ (void) zfs_refcount_remove_many(&old_state->arcs_size, HDR_GET_LSIZE(hdr), hdr); } else { uint32_t buffers = 0; /* * Each individual buffer holds a unique reference, * thus we must remove each of these references one * at a time. */ for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; buf = buf->b_next) { ASSERT3U(bufcnt, !=, 0); buffers++; /* * When the arc_buf_t is sharing the data * block with the hdr, the owner of the * reference belongs to the hdr. Only * add to the refcount if the arc_buf_t is * not shared. */ if (arc_buf_is_shared(buf)) continue; (void) zfs_refcount_remove_many( &old_state->arcs_size, arc_buf_size(buf), buf); } ASSERT3U(bufcnt, ==, buffers); ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); if (hdr->b_l1hdr.b_pabd != NULL) { (void) zfs_refcount_remove_many( &old_state->arcs_size, arc_hdr_size(hdr), hdr); } if (HDR_HAS_RABD(hdr)) { (void) zfs_refcount_remove_many( &old_state->arcs_size, HDR_GET_PSIZE(hdr), hdr); } } } if (HDR_HAS_L1HDR(hdr)) { hdr->b_l1hdr.b_state = new_state; if (HDR_HAS_L2HDR(hdr) && new_state != arc_l2c_only) { l2arc_hdr_arcstats_decrement_state(hdr); hdr->b_l2hdr.b_arcs_state = new_state->arcs_state; l2arc_hdr_arcstats_increment_state(hdr); } } } void arc_space_consume(uint64_t space, arc_space_type_t type) { ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); switch (type) { default: break; case ARC_SPACE_DATA: ARCSTAT_INCR(arcstat_data_size, space); break; case ARC_SPACE_META: ARCSTAT_INCR(arcstat_metadata_size, space); break; case ARC_SPACE_BONUS: ARCSTAT_INCR(arcstat_bonus_size, space); break; case ARC_SPACE_DNODE: aggsum_add(&arc_sums.arcstat_dnode_size, space); break; case ARC_SPACE_DBUF: ARCSTAT_INCR(arcstat_dbuf_size, space); break; case ARC_SPACE_HDRS: ARCSTAT_INCR(arcstat_hdr_size, space); break; case ARC_SPACE_L2HDRS: aggsum_add(&arc_sums.arcstat_l2_hdr_size, space); break; case ARC_SPACE_ABD_CHUNK_WASTE: /* * Note: this includes space wasted by all scatter ABD's, not * just those allocated by the ARC. But the vast majority of * scatter ABD's come from the ARC, because other users are * very short-lived. */ ARCSTAT_INCR(arcstat_abd_chunk_waste_size, space); break; } if (type != ARC_SPACE_DATA && type != ARC_SPACE_ABD_CHUNK_WASTE) aggsum_add(&arc_sums.arcstat_meta_used, space); aggsum_add(&arc_sums.arcstat_size, space); } void arc_space_return(uint64_t space, arc_space_type_t type) { ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); switch (type) { default: break; case ARC_SPACE_DATA: ARCSTAT_INCR(arcstat_data_size, -space); break; case ARC_SPACE_META: ARCSTAT_INCR(arcstat_metadata_size, -space); break; case ARC_SPACE_BONUS: ARCSTAT_INCR(arcstat_bonus_size, -space); break; case ARC_SPACE_DNODE: aggsum_add(&arc_sums.arcstat_dnode_size, -space); break; case ARC_SPACE_DBUF: ARCSTAT_INCR(arcstat_dbuf_size, -space); break; case ARC_SPACE_HDRS: ARCSTAT_INCR(arcstat_hdr_size, -space); break; case ARC_SPACE_L2HDRS: aggsum_add(&arc_sums.arcstat_l2_hdr_size, -space); break; case ARC_SPACE_ABD_CHUNK_WASTE: ARCSTAT_INCR(arcstat_abd_chunk_waste_size, -space); break; } if (type != ARC_SPACE_DATA && type != ARC_SPACE_ABD_CHUNK_WASTE) { ASSERT(aggsum_compare(&arc_sums.arcstat_meta_used, space) >= 0); ARCSTAT_MAX(arcstat_meta_max, aggsum_upper_bound(&arc_sums.arcstat_meta_used)); aggsum_add(&arc_sums.arcstat_meta_used, -space); } ASSERT(aggsum_compare(&arc_sums.arcstat_size, space) >= 0); aggsum_add(&arc_sums.arcstat_size, -space); } /* * Given a hdr and a buf, returns whether that buf can share its b_data buffer * with the hdr's b_pabd. */ static boolean_t arc_can_share(arc_buf_hdr_t *hdr, arc_buf_t *buf) { /* * The criteria for sharing a hdr's data are: * 1. the buffer is not encrypted * 2. the hdr's compression matches the buf's compression * 3. the hdr doesn't need to be byteswapped * 4. the hdr isn't already being shared * 5. the buf is either compressed or it is the last buf in the hdr list * * Criterion #5 maintains the invariant that shared uncompressed * bufs must be the final buf in the hdr's b_buf list. Reading this, you * might ask, "if a compressed buf is allocated first, won't that be the * last thing in the list?", but in that case it's impossible to create * a shared uncompressed buf anyway (because the hdr must be compressed * to have the compressed buf). You might also think that #3 is * sufficient to make this guarantee, however it's possible * (specifically in the rare L2ARC write race mentioned in * arc_buf_alloc_impl()) there will be an existing uncompressed buf that * is shareable, but wasn't at the time of its allocation. Rather than * allow a new shared uncompressed buf to be created and then shuffle * the list around to make it the last element, this simply disallows * sharing if the new buf isn't the first to be added. */ ASSERT3P(buf->b_hdr, ==, hdr); boolean_t hdr_compressed = arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF; boolean_t buf_compressed = ARC_BUF_COMPRESSED(buf) != 0; return (!ARC_BUF_ENCRYPTED(buf) && buf_compressed == hdr_compressed && hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS && !HDR_SHARED_DATA(hdr) && (ARC_BUF_LAST(buf) || ARC_BUF_COMPRESSED(buf))); } /* * Allocate a buf for this hdr. If you care about the data that's in the hdr, * or if you want a compressed buffer, pass those flags in. Returns 0 if the * copy was made successfully, or an error code otherwise. */ static int arc_buf_alloc_impl(arc_buf_hdr_t *hdr, spa_t *spa, const zbookmark_phys_t *zb, const void *tag, boolean_t encrypted, boolean_t compressed, boolean_t noauth, boolean_t fill, arc_buf_t **ret) { arc_buf_t *buf; arc_fill_flags_t flags = ARC_FILL_LOCKED; ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT3U(HDR_GET_LSIZE(hdr), >, 0); VERIFY(hdr->b_type == ARC_BUFC_DATA || hdr->b_type == ARC_BUFC_METADATA); ASSERT3P(ret, !=, NULL); ASSERT3P(*ret, ==, NULL); IMPLY(encrypted, compressed); buf = *ret = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); buf->b_hdr = hdr; buf->b_data = NULL; buf->b_next = hdr->b_l1hdr.b_buf; buf->b_flags = 0; add_reference(hdr, tag); /* * We're about to change the hdr's b_flags. We must either * hold the hash_lock or be undiscoverable. */ ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); /* * Only honor requests for compressed bufs if the hdr is actually * compressed. This must be overridden if the buffer is encrypted since * encrypted buffers cannot be decompressed. */ if (encrypted) { buf->b_flags |= ARC_BUF_FLAG_COMPRESSED; buf->b_flags |= ARC_BUF_FLAG_ENCRYPTED; flags |= ARC_FILL_COMPRESSED | ARC_FILL_ENCRYPTED; } else if (compressed && arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF) { buf->b_flags |= ARC_BUF_FLAG_COMPRESSED; flags |= ARC_FILL_COMPRESSED; } if (noauth) { ASSERT0(encrypted); flags |= ARC_FILL_NOAUTH; } /* * If the hdr's data can be shared then we share the data buffer and * set the appropriate bit in the hdr's b_flags to indicate the hdr is * sharing it's b_pabd with the arc_buf_t. Otherwise, we allocate a new * buffer to store the buf's data. * * There are two additional restrictions here because we're sharing * hdr -> buf instead of the usual buf -> hdr. First, the hdr can't be * actively involved in an L2ARC write, because if this buf is used by * an arc_write() then the hdr's data buffer will be released when the * write completes, even though the L2ARC write might still be using it. * Second, the hdr's ABD must be linear so that the buf's user doesn't * need to be ABD-aware. It must be allocated via * zio_[data_]buf_alloc(), not as a page, because we need to be able * to abd_release_ownership_of_buf(), which isn't allowed on "linear * page" buffers because the ABD code needs to handle freeing them * specially. */ boolean_t can_share = arc_can_share(hdr, buf) && !HDR_L2_WRITING(hdr) && hdr->b_l1hdr.b_pabd != NULL && abd_is_linear(hdr->b_l1hdr.b_pabd) && !abd_is_linear_page(hdr->b_l1hdr.b_pabd); /* Set up b_data and sharing */ if (can_share) { buf->b_data = abd_to_buf(hdr->b_l1hdr.b_pabd); buf->b_flags |= ARC_BUF_FLAG_SHARED; arc_hdr_set_flags(hdr, ARC_FLAG_SHARED_DATA); } else { buf->b_data = arc_get_data_buf(hdr, arc_buf_size(buf), buf); ARCSTAT_INCR(arcstat_overhead_size, arc_buf_size(buf)); } VERIFY3P(buf->b_data, !=, NULL); hdr->b_l1hdr.b_buf = buf; hdr->b_l1hdr.b_bufcnt += 1; if (encrypted) hdr->b_crypt_hdr.b_ebufcnt += 1; /* * If the user wants the data from the hdr, we need to either copy or * decompress the data. */ if (fill) { ASSERT3P(zb, !=, NULL); return (arc_buf_fill(buf, spa, zb, flags)); } return (0); } static const char *arc_onloan_tag = "onloan"; static inline void arc_loaned_bytes_update(int64_t delta) { atomic_add_64(&arc_loaned_bytes, delta); /* assert that it did not wrap around */ ASSERT3S(atomic_add_64_nv(&arc_loaned_bytes, 0), >=, 0); } /* * Loan out an anonymous arc buffer. Loaned buffers are not counted as in * flight data by arc_tempreserve_space() until they are "returned". Loaned * buffers must be returned to the arc before they can be used by the DMU or * freed. */ arc_buf_t * arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size) { arc_buf_t *buf = arc_alloc_buf(spa, arc_onloan_tag, is_metadata ? ARC_BUFC_METADATA : ARC_BUFC_DATA, size); arc_loaned_bytes_update(arc_buf_size(buf)); return (buf); } arc_buf_t * arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize, enum zio_compress compression_type, uint8_t complevel) { arc_buf_t *buf = arc_alloc_compressed_buf(spa, arc_onloan_tag, psize, lsize, compression_type, complevel); arc_loaned_bytes_update(arc_buf_size(buf)); return (buf); } arc_buf_t * arc_loan_raw_buf(spa_t *spa, uint64_t dsobj, boolean_t byteorder, const uint8_t *salt, const uint8_t *iv, const uint8_t *mac, dmu_object_type_t ot, uint64_t psize, uint64_t lsize, enum zio_compress compression_type, uint8_t complevel) { arc_buf_t *buf = arc_alloc_raw_buf(spa, arc_onloan_tag, dsobj, byteorder, salt, iv, mac, ot, psize, lsize, compression_type, complevel); atomic_add_64(&arc_loaned_bytes, psize); return (buf); } /* * Return a loaned arc buffer to the arc. */ void arc_return_buf(arc_buf_t *buf, const void *tag) { arc_buf_hdr_t *hdr = buf->b_hdr; ASSERT3P(buf->b_data, !=, NULL); ASSERT(HDR_HAS_L1HDR(hdr)); (void) zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, tag); (void) zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag); arc_loaned_bytes_update(-arc_buf_size(buf)); } /* Detach an arc_buf from a dbuf (tag) */ void arc_loan_inuse_buf(arc_buf_t *buf, const void *tag) { arc_buf_hdr_t *hdr = buf->b_hdr; ASSERT3P(buf->b_data, !=, NULL); ASSERT(HDR_HAS_L1HDR(hdr)); (void) zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag); (void) zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, tag); arc_loaned_bytes_update(arc_buf_size(buf)); } static void l2arc_free_abd_on_write(abd_t *abd, size_t size, arc_buf_contents_t type) { l2arc_data_free_t *df = kmem_alloc(sizeof (*df), KM_SLEEP); df->l2df_abd = abd; df->l2df_size = size; df->l2df_type = type; mutex_enter(&l2arc_free_on_write_mtx); list_insert_head(l2arc_free_on_write, df); mutex_exit(&l2arc_free_on_write_mtx); } static void arc_hdr_free_on_write(arc_buf_hdr_t *hdr, boolean_t free_rdata) { arc_state_t *state = hdr->b_l1hdr.b_state; arc_buf_contents_t type = arc_buf_type(hdr); uint64_t size = (free_rdata) ? HDR_GET_PSIZE(hdr) : arc_hdr_size(hdr); /* protected by hash lock, if in the hash table */ if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) { ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); ASSERT(state != arc_anon && state != arc_l2c_only); (void) zfs_refcount_remove_many(&state->arcs_esize[type], size, hdr); } (void) zfs_refcount_remove_many(&state->arcs_size, size, hdr); if (type == ARC_BUFC_METADATA) { arc_space_return(size, ARC_SPACE_META); } else { ASSERT(type == ARC_BUFC_DATA); arc_space_return(size, ARC_SPACE_DATA); } if (free_rdata) { l2arc_free_abd_on_write(hdr->b_crypt_hdr.b_rabd, size, type); } else { l2arc_free_abd_on_write(hdr->b_l1hdr.b_pabd, size, type); } } /* * Share the arc_buf_t's data with the hdr. Whenever we are sharing the * data buffer, we transfer the refcount ownership to the hdr and update * the appropriate kstats. */ static void arc_share_buf(arc_buf_hdr_t *hdr, arc_buf_t *buf) { ASSERT(arc_can_share(hdr, buf)); ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!ARC_BUF_ENCRYPTED(buf)); ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); /* * Start sharing the data buffer. We transfer the * refcount ownership to the hdr since it always owns * the refcount whenever an arc_buf_t is shared. */ zfs_refcount_transfer_ownership_many(&hdr->b_l1hdr.b_state->arcs_size, arc_hdr_size(hdr), buf, hdr); hdr->b_l1hdr.b_pabd = abd_get_from_buf(buf->b_data, arc_buf_size(buf)); abd_take_ownership_of_buf(hdr->b_l1hdr.b_pabd, HDR_ISTYPE_METADATA(hdr)); arc_hdr_set_flags(hdr, ARC_FLAG_SHARED_DATA); buf->b_flags |= ARC_BUF_FLAG_SHARED; /* * Since we've transferred ownership to the hdr we need * to increment its compressed and uncompressed kstats and * decrement the overhead size. */ ARCSTAT_INCR(arcstat_compressed_size, arc_hdr_size(hdr)); ARCSTAT_INCR(arcstat_uncompressed_size, HDR_GET_LSIZE(hdr)); ARCSTAT_INCR(arcstat_overhead_size, -arc_buf_size(buf)); } static void arc_unshare_buf(arc_buf_hdr_t *hdr, arc_buf_t *buf) { ASSERT(arc_buf_is_shared(buf)); ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); /* * We are no longer sharing this buffer so we need * to transfer its ownership to the rightful owner. */ zfs_refcount_transfer_ownership_many(&hdr->b_l1hdr.b_state->arcs_size, arc_hdr_size(hdr), hdr, buf); arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA); abd_release_ownership_of_buf(hdr->b_l1hdr.b_pabd); abd_free(hdr->b_l1hdr.b_pabd); hdr->b_l1hdr.b_pabd = NULL; buf->b_flags &= ~ARC_BUF_FLAG_SHARED; /* * Since the buffer is no longer shared between * the arc buf and the hdr, count it as overhead. */ ARCSTAT_INCR(arcstat_compressed_size, -arc_hdr_size(hdr)); ARCSTAT_INCR(arcstat_uncompressed_size, -HDR_GET_LSIZE(hdr)); ARCSTAT_INCR(arcstat_overhead_size, arc_buf_size(buf)); } /* * Remove an arc_buf_t from the hdr's buf list and return the last * arc_buf_t on the list. If no buffers remain on the list then return * NULL. */ static arc_buf_t * arc_buf_remove(arc_buf_hdr_t *hdr, arc_buf_t *buf) { ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); arc_buf_t **bufp = &hdr->b_l1hdr.b_buf; arc_buf_t *lastbuf = NULL; /* * Remove the buf from the hdr list and locate the last * remaining buffer on the list. */ while (*bufp != NULL) { if (*bufp == buf) *bufp = buf->b_next; /* * If we've removed a buffer in the middle of * the list then update the lastbuf and update * bufp. */ if (*bufp != NULL) { lastbuf = *bufp; bufp = &(*bufp)->b_next; } } buf->b_next = NULL; ASSERT3P(lastbuf, !=, buf); IMPLY(hdr->b_l1hdr.b_bufcnt > 0, lastbuf != NULL); IMPLY(hdr->b_l1hdr.b_bufcnt > 0, hdr->b_l1hdr.b_buf != NULL); IMPLY(lastbuf != NULL, ARC_BUF_LAST(lastbuf)); return (lastbuf); } /* * Free up buf->b_data and pull the arc_buf_t off of the arc_buf_hdr_t's * list and free it. */ static void arc_buf_destroy_impl(arc_buf_t *buf) { arc_buf_hdr_t *hdr = buf->b_hdr; /* * Free up the data associated with the buf but only if we're not * sharing this with the hdr. If we are sharing it with the hdr, the * hdr is responsible for doing the free. */ if (buf->b_data != NULL) { /* * We're about to change the hdr's b_flags. We must either * hold the hash_lock or be undiscoverable. */ ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); arc_cksum_verify(buf); arc_buf_unwatch(buf); if (arc_buf_is_shared(buf)) { arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA); } else { uint64_t size = arc_buf_size(buf); arc_free_data_buf(hdr, buf->b_data, size, buf); ARCSTAT_INCR(arcstat_overhead_size, -size); } buf->b_data = NULL; ASSERT(hdr->b_l1hdr.b_bufcnt > 0); hdr->b_l1hdr.b_bufcnt -= 1; if (ARC_BUF_ENCRYPTED(buf)) { hdr->b_crypt_hdr.b_ebufcnt -= 1; /* * If we have no more encrypted buffers and we've * already gotten a copy of the decrypted data we can * free b_rabd to save some space. */ if (hdr->b_crypt_hdr.b_ebufcnt == 0 && HDR_HAS_RABD(hdr) && hdr->b_l1hdr.b_pabd != NULL && !HDR_IO_IN_PROGRESS(hdr)) { arc_hdr_free_abd(hdr, B_TRUE); } } } arc_buf_t *lastbuf = arc_buf_remove(hdr, buf); if (ARC_BUF_SHARED(buf) && !ARC_BUF_COMPRESSED(buf)) { /* * If the current arc_buf_t is sharing its data buffer with the * hdr, then reassign the hdr's b_pabd to share it with the new * buffer at the end of the list. The shared buffer is always * the last one on the hdr's buffer list. * * There is an equivalent case for compressed bufs, but since * they aren't guaranteed to be the last buf in the list and * that is an exceedingly rare case, we just allow that space be * wasted temporarily. We must also be careful not to share * encrypted buffers, since they cannot be shared. */ if (lastbuf != NULL && !ARC_BUF_ENCRYPTED(lastbuf)) { /* Only one buf can be shared at once */ VERIFY(!arc_buf_is_shared(lastbuf)); /* hdr is uncompressed so can't have compressed buf */ VERIFY(!ARC_BUF_COMPRESSED(lastbuf)); ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); arc_hdr_free_abd(hdr, B_FALSE); /* * We must setup a new shared block between the * last buffer and the hdr. The data would have * been allocated by the arc buf so we need to transfer * ownership to the hdr since it's now being shared. */ arc_share_buf(hdr, lastbuf); } } else if (HDR_SHARED_DATA(hdr)) { /* * Uncompressed shared buffers are always at the end * of the list. Compressed buffers don't have the * same requirements. This makes it hard to * simply assert that the lastbuf is shared so * we rely on the hdr's compression flags to determine * if we have a compressed, shared buffer. */ ASSERT3P(lastbuf, !=, NULL); ASSERT(arc_buf_is_shared(lastbuf) || arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF); } /* * Free the checksum if we're removing the last uncompressed buf from * this hdr. */ if (!arc_hdr_has_uncompressed_buf(hdr)) { arc_cksum_free(hdr); } /* clean up the buf */ buf->b_hdr = NULL; kmem_cache_free(buf_cache, buf); } static void arc_hdr_alloc_abd(arc_buf_hdr_t *hdr, int alloc_flags) { uint64_t size; boolean_t alloc_rdata = ((alloc_flags & ARC_HDR_ALLOC_RDATA) != 0); ASSERT3U(HDR_GET_LSIZE(hdr), >, 0); ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT(!HDR_SHARED_DATA(hdr) || alloc_rdata); IMPLY(alloc_rdata, HDR_PROTECTED(hdr)); if (alloc_rdata) { size = HDR_GET_PSIZE(hdr); ASSERT3P(hdr->b_crypt_hdr.b_rabd, ==, NULL); hdr->b_crypt_hdr.b_rabd = arc_get_data_abd(hdr, size, hdr, alloc_flags); ASSERT3P(hdr->b_crypt_hdr.b_rabd, !=, NULL); ARCSTAT_INCR(arcstat_raw_size, size); } else { size = arc_hdr_size(hdr); ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); hdr->b_l1hdr.b_pabd = arc_get_data_abd(hdr, size, hdr, alloc_flags); ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); } ARCSTAT_INCR(arcstat_compressed_size, size); ARCSTAT_INCR(arcstat_uncompressed_size, HDR_GET_LSIZE(hdr)); } static void arc_hdr_free_abd(arc_buf_hdr_t *hdr, boolean_t free_rdata) { uint64_t size = (free_rdata) ? HDR_GET_PSIZE(hdr) : arc_hdr_size(hdr); ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); IMPLY(free_rdata, HDR_HAS_RABD(hdr)); /* * If the hdr is currently being written to the l2arc then * we defer freeing the data by adding it to the l2arc_free_on_write * list. The l2arc will free the data once it's finished * writing it to the l2arc device. */ if (HDR_L2_WRITING(hdr)) { arc_hdr_free_on_write(hdr, free_rdata); ARCSTAT_BUMP(arcstat_l2_free_on_write); } else if (free_rdata) { arc_free_data_abd(hdr, hdr->b_crypt_hdr.b_rabd, size, hdr); } else { arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, size, hdr); } if (free_rdata) { hdr->b_crypt_hdr.b_rabd = NULL; ARCSTAT_INCR(arcstat_raw_size, -size); } else { hdr->b_l1hdr.b_pabd = NULL; } if (hdr->b_l1hdr.b_pabd == NULL && !HDR_HAS_RABD(hdr)) hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; ARCSTAT_INCR(arcstat_compressed_size, -size); ARCSTAT_INCR(arcstat_uncompressed_size, -HDR_GET_LSIZE(hdr)); } /* * Allocate empty anonymous ARC header. The header will get its identity * assigned and buffers attached later as part of read or write operations. * * In case of read arc_read() assigns header its identify (b_dva + b_birth), * inserts it into ARC hash to become globally visible and allocates physical * (b_pabd) or raw (b_rabd) ABD buffer to read into from disk. On disk read * completion arc_read_done() allocates ARC buffer(s) as needed, potentially * sharing one of them with the physical ABD buffer. * * In case of write arc_alloc_buf() allocates ARC buffer to be filled with * data. Then after compression and/or encryption arc_write_ready() allocates * and fills (or potentially shares) physical (b_pabd) or raw (b_rabd) ABD * buffer. On disk write completion arc_write_done() assigns the header its * new identity (b_dva + b_birth) and inserts into ARC hash. * * In case of partial overwrite the old data is read first as described. Then * arc_release() either allocates new anonymous ARC header and moves the ARC * buffer to it, or reuses the old ARC header by discarding its identity and * removing it from ARC hash. After buffer modification normal write process * follows as described. */ static arc_buf_hdr_t * arc_hdr_alloc(uint64_t spa, int32_t psize, int32_t lsize, boolean_t protected, enum zio_compress compression_type, uint8_t complevel, arc_buf_contents_t type) { arc_buf_hdr_t *hdr; VERIFY(type == ARC_BUFC_DATA || type == ARC_BUFC_METADATA); if (protected) { hdr = kmem_cache_alloc(hdr_full_crypt_cache, KM_PUSHPAGE); } else { hdr = kmem_cache_alloc(hdr_full_cache, KM_PUSHPAGE); } ASSERT(HDR_EMPTY(hdr)); ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); HDR_SET_PSIZE(hdr, psize); HDR_SET_LSIZE(hdr, lsize); hdr->b_spa = spa; hdr->b_type = type; hdr->b_flags = 0; arc_hdr_set_flags(hdr, arc_bufc_to_flags(type) | ARC_FLAG_HAS_L1HDR); arc_hdr_set_compress(hdr, compression_type); hdr->b_complevel = complevel; if (protected) arc_hdr_set_flags(hdr, ARC_FLAG_PROTECTED); hdr->b_l1hdr.b_state = arc_anon; hdr->b_l1hdr.b_arc_access = 0; hdr->b_l1hdr.b_mru_hits = 0; hdr->b_l1hdr.b_mru_ghost_hits = 0; hdr->b_l1hdr.b_mfu_hits = 0; hdr->b_l1hdr.b_mfu_ghost_hits = 0; hdr->b_l1hdr.b_bufcnt = 0; hdr->b_l1hdr.b_buf = NULL; ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); return (hdr); } /* * Transition between the two allocation states for the arc_buf_hdr struct. * The arc_buf_hdr struct can be allocated with (hdr_full_cache) or without * (hdr_l2only_cache) the fields necessary for the L1 cache - the smaller * version is used when a cache buffer is only in the L2ARC in order to reduce * memory usage. */ static arc_buf_hdr_t * arc_hdr_realloc(arc_buf_hdr_t *hdr, kmem_cache_t *old, kmem_cache_t *new) { ASSERT(HDR_HAS_L2HDR(hdr)); arc_buf_hdr_t *nhdr; l2arc_dev_t *dev = hdr->b_l2hdr.b_dev; ASSERT((old == hdr_full_cache && new == hdr_l2only_cache) || (old == hdr_l2only_cache && new == hdr_full_cache)); /* * if the caller wanted a new full header and the header is to be * encrypted we will actually allocate the header from the full crypt * cache instead. The same applies to freeing from the old cache. */ if (HDR_PROTECTED(hdr) && new == hdr_full_cache) new = hdr_full_crypt_cache; if (HDR_PROTECTED(hdr) && old == hdr_full_cache) old = hdr_full_crypt_cache; nhdr = kmem_cache_alloc(new, KM_PUSHPAGE); ASSERT(MUTEX_HELD(HDR_LOCK(hdr))); buf_hash_remove(hdr); memcpy(nhdr, hdr, HDR_L2ONLY_SIZE); if (new == hdr_full_cache || new == hdr_full_crypt_cache) { arc_hdr_set_flags(nhdr, ARC_FLAG_HAS_L1HDR); /* * arc_access and arc_change_state need to be aware that a * header has just come out of L2ARC, so we set its state to * l2c_only even though it's about to change. */ nhdr->b_l1hdr.b_state = arc_l2c_only; /* Verify previous threads set to NULL before freeing */ ASSERT3P(nhdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); } else { ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); ASSERT0(hdr->b_l1hdr.b_bufcnt); ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); /* * If we've reached here, We must have been called from * arc_evict_hdr(), as such we should have already been * removed from any ghost list we were previously on * (which protects us from racing with arc_evict_state), * thus no locking is needed during this check. */ ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); /* * A buffer must not be moved into the arc_l2c_only * state if it's not finished being written out to the * l2arc device. Otherwise, the b_l1hdr.b_pabd field * might try to be accessed, even though it was removed. */ VERIFY(!HDR_L2_WRITING(hdr)); VERIFY3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); arc_hdr_clear_flags(nhdr, ARC_FLAG_HAS_L1HDR); } /* * The header has been reallocated so we need to re-insert it into any * lists it was on. */ (void) buf_hash_insert(nhdr, NULL); ASSERT(list_link_active(&hdr->b_l2hdr.b_l2node)); mutex_enter(&dev->l2ad_mtx); /* * We must place the realloc'ed header back into the list at * the same spot. Otherwise, if it's placed earlier in the list, * l2arc_write_buffers() could find it during the function's * write phase, and try to write it out to the l2arc. */ list_insert_after(&dev->l2ad_buflist, hdr, nhdr); list_remove(&dev->l2ad_buflist, hdr); mutex_exit(&dev->l2ad_mtx); /* * Since we're using the pointer address as the tag when * incrementing and decrementing the l2ad_alloc refcount, we * must remove the old pointer (that we're about to destroy) and * add the new pointer to the refcount. Otherwise we'd remove * the wrong pointer address when calling arc_hdr_destroy() later. */ (void) zfs_refcount_remove_many(&dev->l2ad_alloc, arc_hdr_size(hdr), hdr); (void) zfs_refcount_add_many(&dev->l2ad_alloc, arc_hdr_size(nhdr), nhdr); buf_discard_identity(hdr); kmem_cache_free(old, hdr); return (nhdr); } /* * This function allows an L1 header to be reallocated as a crypt * header and vice versa. If we are going to a crypt header, the * new fields will be zeroed out. */ static arc_buf_hdr_t * arc_hdr_realloc_crypt(arc_buf_hdr_t *hdr, boolean_t need_crypt) { arc_buf_hdr_t *nhdr; arc_buf_t *buf; kmem_cache_t *ncache, *ocache; /* * This function requires that hdr is in the arc_anon state. * Therefore it won't have any L2ARC data for us to worry * about copying. */ ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT(!HDR_HAS_L2HDR(hdr)); ASSERT3U(!!HDR_PROTECTED(hdr), !=, need_crypt); ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); ASSERT(!list_link_active(&hdr->b_l2hdr.b_l2node)); ASSERT3P(hdr->b_hash_next, ==, NULL); if (need_crypt) { ncache = hdr_full_crypt_cache; ocache = hdr_full_cache; } else { ncache = hdr_full_cache; ocache = hdr_full_crypt_cache; } nhdr = kmem_cache_alloc(ncache, KM_PUSHPAGE); /* * Copy all members that aren't locks or condvars to the new header. * No lists are pointing to us (as we asserted above), so we don't * need to worry about the list nodes. */ nhdr->b_dva = hdr->b_dva; nhdr->b_birth = hdr->b_birth; nhdr->b_type = hdr->b_type; nhdr->b_flags = hdr->b_flags; nhdr->b_psize = hdr->b_psize; nhdr->b_lsize = hdr->b_lsize; nhdr->b_spa = hdr->b_spa; nhdr->b_l1hdr.b_freeze_cksum = hdr->b_l1hdr.b_freeze_cksum; nhdr->b_l1hdr.b_bufcnt = hdr->b_l1hdr.b_bufcnt; nhdr->b_l1hdr.b_byteswap = hdr->b_l1hdr.b_byteswap; nhdr->b_l1hdr.b_state = hdr->b_l1hdr.b_state; nhdr->b_l1hdr.b_arc_access = hdr->b_l1hdr.b_arc_access; nhdr->b_l1hdr.b_mru_hits = hdr->b_l1hdr.b_mru_hits; nhdr->b_l1hdr.b_mru_ghost_hits = hdr->b_l1hdr.b_mru_ghost_hits; nhdr->b_l1hdr.b_mfu_hits = hdr->b_l1hdr.b_mfu_hits; nhdr->b_l1hdr.b_mfu_ghost_hits = hdr->b_l1hdr.b_mfu_ghost_hits; nhdr->b_l1hdr.b_acb = hdr->b_l1hdr.b_acb; nhdr->b_l1hdr.b_pabd = hdr->b_l1hdr.b_pabd; /* * This zfs_refcount_add() exists only to ensure that the individual * arc buffers always point to a header that is referenced, avoiding * a small race condition that could trigger ASSERTs. */ (void) zfs_refcount_add(&nhdr->b_l1hdr.b_refcnt, FTAG); nhdr->b_l1hdr.b_buf = hdr->b_l1hdr.b_buf; for (buf = nhdr->b_l1hdr.b_buf; buf != NULL; buf = buf->b_next) { mutex_enter(&buf->b_evict_lock); buf->b_hdr = nhdr; mutex_exit(&buf->b_evict_lock); } zfs_refcount_transfer(&nhdr->b_l1hdr.b_refcnt, &hdr->b_l1hdr.b_refcnt); (void) zfs_refcount_remove(&nhdr->b_l1hdr.b_refcnt, FTAG); ASSERT0(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt)); if (need_crypt) { arc_hdr_set_flags(nhdr, ARC_FLAG_PROTECTED); } else { arc_hdr_clear_flags(nhdr, ARC_FLAG_PROTECTED); } /* unset all members of the original hdr */ memset(&hdr->b_dva, 0, sizeof (dva_t)); hdr->b_birth = 0; hdr->b_type = ARC_BUFC_INVALID; hdr->b_flags = 0; hdr->b_psize = 0; hdr->b_lsize = 0; hdr->b_spa = 0; hdr->b_l1hdr.b_freeze_cksum = NULL; hdr->b_l1hdr.b_buf = NULL; hdr->b_l1hdr.b_bufcnt = 0; hdr->b_l1hdr.b_byteswap = 0; hdr->b_l1hdr.b_state = NULL; hdr->b_l1hdr.b_arc_access = 0; hdr->b_l1hdr.b_mru_hits = 0; hdr->b_l1hdr.b_mru_ghost_hits = 0; hdr->b_l1hdr.b_mfu_hits = 0; hdr->b_l1hdr.b_mfu_ghost_hits = 0; hdr->b_l1hdr.b_acb = NULL; hdr->b_l1hdr.b_pabd = NULL; if (ocache == hdr_full_crypt_cache) { ASSERT(!HDR_HAS_RABD(hdr)); hdr->b_crypt_hdr.b_ot = DMU_OT_NONE; hdr->b_crypt_hdr.b_ebufcnt = 0; hdr->b_crypt_hdr.b_dsobj = 0; memset(hdr->b_crypt_hdr.b_salt, 0, ZIO_DATA_SALT_LEN); memset(hdr->b_crypt_hdr.b_iv, 0, ZIO_DATA_IV_LEN); memset(hdr->b_crypt_hdr.b_mac, 0, ZIO_DATA_MAC_LEN); } buf_discard_identity(hdr); kmem_cache_free(ocache, hdr); return (nhdr); } /* * This function is used by the send / receive code to convert a newly * allocated arc_buf_t to one that is suitable for a raw encrypted write. It * is also used to allow the root objset block to be updated without altering * its embedded MACs. Both block types will always be uncompressed so we do not * have to worry about compression type or psize. */ void arc_convert_to_raw(arc_buf_t *buf, uint64_t dsobj, boolean_t byteorder, dmu_object_type_t ot, const uint8_t *salt, const uint8_t *iv, const uint8_t *mac) { arc_buf_hdr_t *hdr = buf->b_hdr; ASSERT(ot == DMU_OT_DNODE || ot == DMU_OT_OBJSET); ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); buf->b_flags |= (ARC_BUF_FLAG_COMPRESSED | ARC_BUF_FLAG_ENCRYPTED); if (!HDR_PROTECTED(hdr)) hdr = arc_hdr_realloc_crypt(hdr, B_TRUE); hdr->b_crypt_hdr.b_dsobj = dsobj; hdr->b_crypt_hdr.b_ot = ot; hdr->b_l1hdr.b_byteswap = (byteorder == ZFS_HOST_BYTEORDER) ? DMU_BSWAP_NUMFUNCS : DMU_OT_BYTESWAP(ot); if (!arc_hdr_has_uncompressed_buf(hdr)) arc_cksum_free(hdr); if (salt != NULL) memcpy(hdr->b_crypt_hdr.b_salt, salt, ZIO_DATA_SALT_LEN); if (iv != NULL) memcpy(hdr->b_crypt_hdr.b_iv, iv, ZIO_DATA_IV_LEN); if (mac != NULL) memcpy(hdr->b_crypt_hdr.b_mac, mac, ZIO_DATA_MAC_LEN); } /* * Allocate a new arc_buf_hdr_t and arc_buf_t and return the buf to the caller. * The buf is returned thawed since we expect the consumer to modify it. */ arc_buf_t * arc_alloc_buf(spa_t *spa, const void *tag, arc_buf_contents_t type, int32_t size) { arc_buf_hdr_t *hdr = arc_hdr_alloc(spa_load_guid(spa), size, size, B_FALSE, ZIO_COMPRESS_OFF, 0, type); arc_buf_t *buf = NULL; VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_FALSE, B_FALSE, B_FALSE, B_FALSE, &buf)); arc_buf_thaw(buf); return (buf); } /* * Allocate a compressed buf in the same manner as arc_alloc_buf. Don't use this * for bufs containing metadata. */ arc_buf_t * arc_alloc_compressed_buf(spa_t *spa, const void *tag, uint64_t psize, uint64_t lsize, enum zio_compress compression_type, uint8_t complevel) { ASSERT3U(lsize, >, 0); ASSERT3U(lsize, >=, psize); ASSERT3U(compression_type, >, ZIO_COMPRESS_OFF); ASSERT3U(compression_type, <, ZIO_COMPRESS_FUNCTIONS); arc_buf_hdr_t *hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize, B_FALSE, compression_type, complevel, ARC_BUFC_DATA); arc_buf_t *buf = NULL; VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_FALSE, B_TRUE, B_FALSE, B_FALSE, &buf)); arc_buf_thaw(buf); ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); /* * To ensure that the hdr has the correct data in it if we call * arc_untransform() on this buf before it's been written to disk, * it's easiest if we just set up sharing between the buf and the hdr. */ arc_share_buf(hdr, buf); return (buf); } arc_buf_t * arc_alloc_raw_buf(spa_t *spa, const void *tag, uint64_t dsobj, boolean_t byteorder, const uint8_t *salt, const uint8_t *iv, const uint8_t *mac, dmu_object_type_t ot, uint64_t psize, uint64_t lsize, enum zio_compress compression_type, uint8_t complevel) { arc_buf_hdr_t *hdr; arc_buf_t *buf; arc_buf_contents_t type = DMU_OT_IS_METADATA(ot) ? ARC_BUFC_METADATA : ARC_BUFC_DATA; ASSERT3U(lsize, >, 0); ASSERT3U(lsize, >=, psize); ASSERT3U(compression_type, >=, ZIO_COMPRESS_OFF); ASSERT3U(compression_type, <, ZIO_COMPRESS_FUNCTIONS); hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize, B_TRUE, compression_type, complevel, type); hdr->b_crypt_hdr.b_dsobj = dsobj; hdr->b_crypt_hdr.b_ot = ot; hdr->b_l1hdr.b_byteswap = (byteorder == ZFS_HOST_BYTEORDER) ? DMU_BSWAP_NUMFUNCS : DMU_OT_BYTESWAP(ot); memcpy(hdr->b_crypt_hdr.b_salt, salt, ZIO_DATA_SALT_LEN); memcpy(hdr->b_crypt_hdr.b_iv, iv, ZIO_DATA_IV_LEN); memcpy(hdr->b_crypt_hdr.b_mac, mac, ZIO_DATA_MAC_LEN); /* * This buffer will be considered encrypted even if the ot is not an * encrypted type. It will become authenticated instead in * arc_write_ready(). */ buf = NULL; VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_TRUE, B_TRUE, B_FALSE, B_FALSE, &buf)); arc_buf_thaw(buf); ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); return (buf); } static void l2arc_hdr_arcstats_update(arc_buf_hdr_t *hdr, boolean_t incr, boolean_t state_only) { l2arc_buf_hdr_t *l2hdr = &hdr->b_l2hdr; l2arc_dev_t *dev = l2hdr->b_dev; uint64_t lsize = HDR_GET_LSIZE(hdr); uint64_t psize = HDR_GET_PSIZE(hdr); uint64_t asize = vdev_psize_to_asize(dev->l2ad_vdev, psize); arc_buf_contents_t type = hdr->b_type; int64_t lsize_s; int64_t psize_s; int64_t asize_s; if (incr) { lsize_s = lsize; psize_s = psize; asize_s = asize; } else { lsize_s = -lsize; psize_s = -psize; asize_s = -asize; } /* If the buffer is a prefetch, count it as such. */ if (HDR_PREFETCH(hdr)) { ARCSTAT_INCR(arcstat_l2_prefetch_asize, asize_s); } else { /* * We use the value stored in the L2 header upon initial * caching in L2ARC. This value will be updated in case * an MRU/MRU_ghost buffer transitions to MFU but the L2ARC * metadata (log entry) cannot currently be updated. Having * the ARC state in the L2 header solves the problem of a * possibly absent L1 header (apparent in buffers restored * from persistent L2ARC). */ switch (hdr->b_l2hdr.b_arcs_state) { case ARC_STATE_MRU_GHOST: case ARC_STATE_MRU: ARCSTAT_INCR(arcstat_l2_mru_asize, asize_s); break; case ARC_STATE_MFU_GHOST: case ARC_STATE_MFU: ARCSTAT_INCR(arcstat_l2_mfu_asize, asize_s); break; default: break; } } if (state_only) return; ARCSTAT_INCR(arcstat_l2_psize, psize_s); ARCSTAT_INCR(arcstat_l2_lsize, lsize_s); switch (type) { case ARC_BUFC_DATA: ARCSTAT_INCR(arcstat_l2_bufc_data_asize, asize_s); break; case ARC_BUFC_METADATA: ARCSTAT_INCR(arcstat_l2_bufc_metadata_asize, asize_s); break; default: break; } } static void arc_hdr_l2hdr_destroy(arc_buf_hdr_t *hdr) { l2arc_buf_hdr_t *l2hdr = &hdr->b_l2hdr; l2arc_dev_t *dev = l2hdr->b_dev; uint64_t psize = HDR_GET_PSIZE(hdr); uint64_t asize = vdev_psize_to_asize(dev->l2ad_vdev, psize); ASSERT(MUTEX_HELD(&dev->l2ad_mtx)); ASSERT(HDR_HAS_L2HDR(hdr)); list_remove(&dev->l2ad_buflist, hdr); l2arc_hdr_arcstats_decrement(hdr); vdev_space_update(dev->l2ad_vdev, -asize, 0, 0); (void) zfs_refcount_remove_many(&dev->l2ad_alloc, arc_hdr_size(hdr), hdr); arc_hdr_clear_flags(hdr, ARC_FLAG_HAS_L2HDR); } static void arc_hdr_destroy(arc_buf_hdr_t *hdr) { if (HDR_HAS_L1HDR(hdr)) { ASSERT(hdr->b_l1hdr.b_buf == NULL || hdr->b_l1hdr.b_bufcnt > 0); ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); } ASSERT(!HDR_IO_IN_PROGRESS(hdr)); ASSERT(!HDR_IN_HASH_TABLE(hdr)); if (HDR_HAS_L2HDR(hdr)) { l2arc_dev_t *dev = hdr->b_l2hdr.b_dev; boolean_t buflist_held = MUTEX_HELD(&dev->l2ad_mtx); if (!buflist_held) mutex_enter(&dev->l2ad_mtx); /* * Even though we checked this conditional above, we * need to check this again now that we have the * l2ad_mtx. This is because we could be racing with * another thread calling l2arc_evict() which might have * destroyed this header's L2 portion as we were waiting * to acquire the l2ad_mtx. If that happens, we don't * want to re-destroy the header's L2 portion. */ if (HDR_HAS_L2HDR(hdr)) { if (!HDR_EMPTY(hdr)) buf_discard_identity(hdr); arc_hdr_l2hdr_destroy(hdr); } if (!buflist_held) mutex_exit(&dev->l2ad_mtx); } /* * The header's identify can only be safely discarded once it is no * longer discoverable. This requires removing it from the hash table * and the l2arc header list. After this point the hash lock can not * be used to protect the header. */ if (!HDR_EMPTY(hdr)) buf_discard_identity(hdr); if (HDR_HAS_L1HDR(hdr)) { arc_cksum_free(hdr); while (hdr->b_l1hdr.b_buf != NULL) arc_buf_destroy_impl(hdr->b_l1hdr.b_buf); if (hdr->b_l1hdr.b_pabd != NULL) arc_hdr_free_abd(hdr, B_FALSE); if (HDR_HAS_RABD(hdr)) arc_hdr_free_abd(hdr, B_TRUE); } ASSERT3P(hdr->b_hash_next, ==, NULL); if (HDR_HAS_L1HDR(hdr)) { ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); if (!HDR_PROTECTED(hdr)) { kmem_cache_free(hdr_full_cache, hdr); } else { kmem_cache_free(hdr_full_crypt_cache, hdr); } } else { kmem_cache_free(hdr_l2only_cache, hdr); } } void arc_buf_destroy(arc_buf_t *buf, const void *tag) { arc_buf_hdr_t *hdr = buf->b_hdr; if (hdr->b_l1hdr.b_state == arc_anon) { ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1); ASSERT(!HDR_IO_IN_PROGRESS(hdr)); VERIFY0(remove_reference(hdr, NULL, tag)); arc_hdr_destroy(hdr); return; } kmutex_t *hash_lock = HDR_LOCK(hdr); mutex_enter(hash_lock); ASSERT3P(hdr, ==, buf->b_hdr); ASSERT(hdr->b_l1hdr.b_bufcnt > 0); ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); ASSERT3P(hdr->b_l1hdr.b_state, !=, arc_anon); ASSERT3P(buf->b_data, !=, NULL); (void) remove_reference(hdr, hash_lock, tag); arc_buf_destroy_impl(buf); mutex_exit(hash_lock); } /* * Evict the arc_buf_hdr that is provided as a parameter. The resultant * state of the header is dependent on its state prior to entering this * function. The following transitions are possible: * * - arc_mru -> arc_mru_ghost * - arc_mfu -> arc_mfu_ghost * - arc_mru_ghost -> arc_l2c_only * - arc_mru_ghost -> deleted * - arc_mfu_ghost -> arc_l2c_only * - arc_mfu_ghost -> deleted * * Return total size of evicted data buffers for eviction progress tracking. * When evicting from ghost states return logical buffer size to make eviction * progress at the same (or at least comparable) rate as from non-ghost states. * * Return *real_evicted for actual ARC size reduction to wake up threads * waiting for it. For non-ghost states it includes size of evicted data * buffers (the headers are not freed there). For ghost states it includes * only the evicted headers size. */ static int64_t arc_evict_hdr(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, uint64_t *real_evicted) { arc_state_t *evicted_state, *state; int64_t bytes_evicted = 0; int min_lifetime = HDR_PRESCIENT_PREFETCH(hdr) ? arc_min_prescient_prefetch_ms : arc_min_prefetch_ms; ASSERT(MUTEX_HELD(hash_lock)); ASSERT(HDR_HAS_L1HDR(hdr)); *real_evicted = 0; state = hdr->b_l1hdr.b_state; if (GHOST_STATE(state)) { ASSERT(!HDR_IO_IN_PROGRESS(hdr)); ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); /* * l2arc_write_buffers() relies on a header's L1 portion * (i.e. its b_pabd field) during it's write phase. * Thus, we cannot push a header onto the arc_l2c_only * state (removing its L1 piece) until the header is * done being written to the l2arc. */ if (HDR_HAS_L2HDR(hdr) && HDR_L2_WRITING(hdr)) { ARCSTAT_BUMP(arcstat_evict_l2_skip); return (bytes_evicted); } ARCSTAT_BUMP(arcstat_deleted); bytes_evicted += HDR_GET_LSIZE(hdr); DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, hdr); if (HDR_HAS_L2HDR(hdr)) { ASSERT(hdr->b_l1hdr.b_pabd == NULL); ASSERT(!HDR_HAS_RABD(hdr)); /* * This buffer is cached on the 2nd Level ARC; * don't destroy the header. */ arc_change_state(arc_l2c_only, hdr, hash_lock); /* * dropping from L1+L2 cached to L2-only, * realloc to remove the L1 header. */ hdr = arc_hdr_realloc(hdr, hdr_full_cache, hdr_l2only_cache); *real_evicted += HDR_FULL_SIZE - HDR_L2ONLY_SIZE; } else { arc_change_state(arc_anon, hdr, hash_lock); arc_hdr_destroy(hdr); *real_evicted += HDR_FULL_SIZE; } return (bytes_evicted); } ASSERT(state == arc_mru || state == arc_mfu); evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; /* prefetch buffers have a minimum lifespan */ if (HDR_IO_IN_PROGRESS(hdr) || ((hdr->b_flags & (ARC_FLAG_PREFETCH | ARC_FLAG_INDIRECT)) && ddi_get_lbolt() - hdr->b_l1hdr.b_arc_access < MSEC_TO_TICK(min_lifetime))) { ARCSTAT_BUMP(arcstat_evict_skip); return (bytes_evicted); } ASSERT0(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt)); while (hdr->b_l1hdr.b_buf) { arc_buf_t *buf = hdr->b_l1hdr.b_buf; if (!mutex_tryenter(&buf->b_evict_lock)) { ARCSTAT_BUMP(arcstat_mutex_miss); break; } if (buf->b_data != NULL) { bytes_evicted += HDR_GET_LSIZE(hdr); *real_evicted += HDR_GET_LSIZE(hdr); } mutex_exit(&buf->b_evict_lock); arc_buf_destroy_impl(buf); } if (HDR_HAS_L2HDR(hdr)) { ARCSTAT_INCR(arcstat_evict_l2_cached, HDR_GET_LSIZE(hdr)); } else { if (l2arc_write_eligible(hdr->b_spa, hdr)) { ARCSTAT_INCR(arcstat_evict_l2_eligible, HDR_GET_LSIZE(hdr)); switch (state->arcs_state) { case ARC_STATE_MRU: ARCSTAT_INCR( arcstat_evict_l2_eligible_mru, HDR_GET_LSIZE(hdr)); break; case ARC_STATE_MFU: ARCSTAT_INCR( arcstat_evict_l2_eligible_mfu, HDR_GET_LSIZE(hdr)); break; default: break; } } else { ARCSTAT_INCR(arcstat_evict_l2_ineligible, HDR_GET_LSIZE(hdr)); } } if (hdr->b_l1hdr.b_bufcnt == 0) { arc_cksum_free(hdr); bytes_evicted += arc_hdr_size(hdr); *real_evicted += arc_hdr_size(hdr); /* * If this hdr is being evicted and has a compressed * buffer then we discard it here before we change states. * This ensures that the accounting is updated correctly * in arc_free_data_impl(). */ if (hdr->b_l1hdr.b_pabd != NULL) arc_hdr_free_abd(hdr, B_FALSE); if (HDR_HAS_RABD(hdr)) arc_hdr_free_abd(hdr, B_TRUE); arc_change_state(evicted_state, hdr, hash_lock); ASSERT(HDR_IN_HASH_TABLE(hdr)); arc_hdr_set_flags(hdr, ARC_FLAG_IN_HASH_TABLE); DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, hdr); } return (bytes_evicted); } static void arc_set_need_free(void) { ASSERT(MUTEX_HELD(&arc_evict_lock)); int64_t remaining = arc_free_memory() - arc_sys_free / 2; arc_evict_waiter_t *aw = list_tail(&arc_evict_waiters); if (aw == NULL) { arc_need_free = MAX(-remaining, 0); } else { arc_need_free = MAX(-remaining, (int64_t)(aw->aew_count - arc_evict_count)); } } static uint64_t arc_evict_state_impl(multilist_t *ml, int idx, arc_buf_hdr_t *marker, uint64_t spa, uint64_t bytes) { multilist_sublist_t *mls; uint64_t bytes_evicted = 0, real_evicted = 0; arc_buf_hdr_t *hdr; kmutex_t *hash_lock; int evict_count = zfs_arc_evict_batch_limit; ASSERT3P(marker, !=, NULL); mls = multilist_sublist_lock(ml, idx); for (hdr = multilist_sublist_prev(mls, marker); likely(hdr != NULL); hdr = multilist_sublist_prev(mls, marker)) { if ((evict_count <= 0) || (bytes_evicted >= bytes)) break; /* * To keep our iteration location, move the marker * forward. Since we're not holding hdr's hash lock, we * must be very careful and not remove 'hdr' from the * sublist. Otherwise, other consumers might mistake the * 'hdr' as not being on a sublist when they call the * multilist_link_active() function (they all rely on * the hash lock protecting concurrent insertions and * removals). multilist_sublist_move_forward() was * specifically implemented to ensure this is the case * (only 'marker' will be removed and re-inserted). */ multilist_sublist_move_forward(mls, marker); /* * The only case where the b_spa field should ever be * zero, is the marker headers inserted by * arc_evict_state(). It's possible for multiple threads * to be calling arc_evict_state() concurrently (e.g. * dsl_pool_close() and zio_inject_fault()), so we must * skip any markers we see from these other threads. */ if (hdr->b_spa == 0) continue; /* we're only interested in evicting buffers of a certain spa */ if (spa != 0 && hdr->b_spa != spa) { ARCSTAT_BUMP(arcstat_evict_skip); continue; } hash_lock = HDR_LOCK(hdr); /* * We aren't calling this function from any code path * that would already be holding a hash lock, so we're * asserting on this assumption to be defensive in case * this ever changes. Without this check, it would be * possible to incorrectly increment arcstat_mutex_miss * below (e.g. if the code changed such that we called * this function with a hash lock held). */ ASSERT(!MUTEX_HELD(hash_lock)); if (mutex_tryenter(hash_lock)) { uint64_t revicted; uint64_t evicted = arc_evict_hdr(hdr, hash_lock, &revicted); mutex_exit(hash_lock); bytes_evicted += evicted; real_evicted += revicted; /* * If evicted is zero, arc_evict_hdr() must have * decided to skip this header, don't increment * evict_count in this case. */ if (evicted != 0) evict_count--; } else { ARCSTAT_BUMP(arcstat_mutex_miss); } } multilist_sublist_unlock(mls); /* * Increment the count of evicted bytes, and wake up any threads that * are waiting for the count to reach this value. Since the list is * ordered by ascending aew_count, we pop off the beginning of the * list until we reach the end, or a waiter that's past the current * "count". Doing this outside the loop reduces the number of times * we need to acquire the global arc_evict_lock. * * Only wake when there's sufficient free memory in the system * (specifically, arc_sys_free/2, which by default is a bit more than * 1/64th of RAM). See the comments in arc_wait_for_eviction(). */ mutex_enter(&arc_evict_lock); arc_evict_count += real_evicted; if (arc_free_memory() > arc_sys_free / 2) { arc_evict_waiter_t *aw; while ((aw = list_head(&arc_evict_waiters)) != NULL && aw->aew_count <= arc_evict_count) { list_remove(&arc_evict_waiters, aw); cv_broadcast(&aw->aew_cv); } } arc_set_need_free(); mutex_exit(&arc_evict_lock); /* * If the ARC size is reduced from arc_c_max to arc_c_min (especially * if the average cached block is small), eviction can be on-CPU for * many seconds. To ensure that other threads that may be bound to * this CPU are able to make progress, make a voluntary preemption * call here. */ - cond_resched(); + kpreempt(KPREEMPT_SYNC); return (bytes_evicted); } /* * Allocate an array of buffer headers used as placeholders during arc state * eviction. */ static arc_buf_hdr_t ** arc_state_alloc_markers(int count) { arc_buf_hdr_t **markers; markers = kmem_zalloc(sizeof (*markers) * count, KM_SLEEP); for (int i = 0; i < count; i++) { markers[i] = kmem_cache_alloc(hdr_full_cache, KM_SLEEP); /* * A b_spa of 0 is used to indicate that this header is * a marker. This fact is used in arc_evict_type() and * arc_evict_state_impl(). */ markers[i]->b_spa = 0; } return (markers); } static void arc_state_free_markers(arc_buf_hdr_t **markers, int count) { for (int i = 0; i < count; i++) kmem_cache_free(hdr_full_cache, markers[i]); kmem_free(markers, sizeof (*markers) * count); } /* * Evict buffers from the given arc state, until we've removed the * specified number of bytes. Move the removed buffers to the * appropriate evict state. * * This function makes a "best effort". It skips over any buffers * it can't get a hash_lock on, and so, may not catch all candidates. * It may also return without evicting as much space as requested. * * If bytes is specified using the special value ARC_EVICT_ALL, this * will evict all available (i.e. unlocked and evictable) buffers from * the given arc state; which is used by arc_flush(). */ static uint64_t arc_evict_state(arc_state_t *state, uint64_t spa, uint64_t bytes, arc_buf_contents_t type) { uint64_t total_evicted = 0; multilist_t *ml = &state->arcs_list[type]; int num_sublists; arc_buf_hdr_t **markers; num_sublists = multilist_get_num_sublists(ml); /* * If we've tried to evict from each sublist, made some * progress, but still have not hit the target number of bytes * to evict, we want to keep trying. The markers allow us to * pick up where we left off for each individual sublist, rather * than starting from the tail each time. */ if (zthr_iscurthread(arc_evict_zthr)) { markers = arc_state_evict_markers; ASSERT3S(num_sublists, <=, arc_state_evict_marker_count); } else { markers = arc_state_alloc_markers(num_sublists); } for (int i = 0; i < num_sublists; i++) { multilist_sublist_t *mls; mls = multilist_sublist_lock(ml, i); multilist_sublist_insert_tail(mls, markers[i]); multilist_sublist_unlock(mls); } /* * While we haven't hit our target number of bytes to evict, or * we're evicting all available buffers. */ while (total_evicted < bytes) { int sublist_idx = multilist_get_random_index(ml); uint64_t scan_evicted = 0; /* * Try to reduce pinned dnodes with a floor of arc_dnode_limit. * Request that 10% of the LRUs be scanned by the superblock * shrinker. */ if (type == ARC_BUFC_DATA && aggsum_compare( &arc_sums.arcstat_dnode_size, arc_dnode_size_limit) > 0) { arc_prune_async((aggsum_upper_bound( &arc_sums.arcstat_dnode_size) - arc_dnode_size_limit) / sizeof (dnode_t) / zfs_arc_dnode_reduce_percent); } /* * Start eviction using a randomly selected sublist, * this is to try and evenly balance eviction across all * sublists. Always starting at the same sublist * (e.g. index 0) would cause evictions to favor certain * sublists over others. */ for (int i = 0; i < num_sublists; i++) { uint64_t bytes_remaining; uint64_t bytes_evicted; if (total_evicted < bytes) bytes_remaining = bytes - total_evicted; else break; bytes_evicted = arc_evict_state_impl(ml, sublist_idx, markers[sublist_idx], spa, bytes_remaining); scan_evicted += bytes_evicted; total_evicted += bytes_evicted; /* we've reached the end, wrap to the beginning */ if (++sublist_idx >= num_sublists) sublist_idx = 0; } /* * If we didn't evict anything during this scan, we have * no reason to believe we'll evict more during another * scan, so break the loop. */ if (scan_evicted == 0) { /* This isn't possible, let's make that obvious */ ASSERT3S(bytes, !=, 0); /* * When bytes is ARC_EVICT_ALL, the only way to * break the loop is when scan_evicted is zero. * In that case, we actually have evicted enough, * so we don't want to increment the kstat. */ if (bytes != ARC_EVICT_ALL) { ASSERT3S(total_evicted, <, bytes); ARCSTAT_BUMP(arcstat_evict_not_enough); } break; } } for (int i = 0; i < num_sublists; i++) { multilist_sublist_t *mls = multilist_sublist_lock(ml, i); multilist_sublist_remove(mls, markers[i]); multilist_sublist_unlock(mls); } if (markers != arc_state_evict_markers) arc_state_free_markers(markers, num_sublists); return (total_evicted); } /* * Flush all "evictable" data of the given type from the arc state * specified. This will not evict any "active" buffers (i.e. referenced). * * When 'retry' is set to B_FALSE, the function will make a single pass * over the state and evict any buffers that it can. Since it doesn't * continually retry the eviction, it might end up leaving some buffers * in the ARC due to lock misses. * * When 'retry' is set to B_TRUE, the function will continually retry the * eviction until *all* evictable buffers have been removed from the * state. As a result, if concurrent insertions into the state are * allowed (e.g. if the ARC isn't shutting down), this function might * wind up in an infinite loop, continually trying to evict buffers. */ static uint64_t arc_flush_state(arc_state_t *state, uint64_t spa, arc_buf_contents_t type, boolean_t retry) { uint64_t evicted = 0; while (zfs_refcount_count(&state->arcs_esize[type]) != 0) { evicted += arc_evict_state(state, spa, ARC_EVICT_ALL, type); if (!retry) break; } return (evicted); } /* * Evict the specified number of bytes from the state specified, * restricting eviction to the spa and type given. This function * prevents us from trying to evict more from a state's list than * is "evictable", and to skip evicting altogether when passed a * negative value for "bytes". In contrast, arc_evict_state() will * evict everything it can, when passed a negative value for "bytes". */ static uint64_t arc_evict_impl(arc_state_t *state, uint64_t spa, int64_t bytes, arc_buf_contents_t type) { uint64_t delta; if (bytes > 0 && zfs_refcount_count(&state->arcs_esize[type]) > 0) { delta = MIN(zfs_refcount_count(&state->arcs_esize[type]), bytes); return (arc_evict_state(state, spa, delta, type)); } return (0); } /* * The goal of this function is to evict enough meta data buffers from the * ARC in order to enforce the arc_meta_limit. Achieving this is slightly * more complicated than it appears because it is common for data buffers * to have holds on meta data buffers. In addition, dnode meta data buffers * will be held by the dnodes in the block preventing them from being freed. * This means we can't simply traverse the ARC and expect to always find * enough unheld meta data buffer to release. * * Therefore, this function has been updated to make alternating passes * over the ARC releasing data buffers and then newly unheld meta data * buffers. This ensures forward progress is maintained and meta_used * will decrease. Normally this is sufficient, but if required the ARC * will call the registered prune callbacks causing dentry and inodes to * be dropped from the VFS cache. This will make dnode meta data buffers * available for reclaim. */ static uint64_t arc_evict_meta_balanced(uint64_t meta_used) { int64_t delta, prune = 0, adjustmnt; uint64_t total_evicted = 0; arc_buf_contents_t type = ARC_BUFC_DATA; int restarts = MAX(zfs_arc_meta_adjust_restarts, 0); restart: /* * This slightly differs than the way we evict from the mru in * arc_evict because we don't have a "target" value (i.e. no * "meta" arc_p). As a result, I think we can completely * cannibalize the metadata in the MRU before we evict the * metadata from the MFU. I think we probably need to implement a * "metadata arc_p" value to do this properly. */ adjustmnt = meta_used - arc_meta_limit; if (adjustmnt > 0 && zfs_refcount_count(&arc_mru->arcs_esize[type]) > 0) { delta = MIN(zfs_refcount_count(&arc_mru->arcs_esize[type]), adjustmnt); total_evicted += arc_evict_impl(arc_mru, 0, delta, type); adjustmnt -= delta; } /* * We can't afford to recalculate adjustmnt here. If we do, * new metadata buffers can sneak into the MRU or ANON lists, * thus penalize the MFU metadata. Although the fudge factor is * small, it has been empirically shown to be significant for * certain workloads (e.g. creating many empty directories). As * such, we use the original calculation for adjustmnt, and * simply decrement the amount of data evicted from the MRU. */ if (adjustmnt > 0 && zfs_refcount_count(&arc_mfu->arcs_esize[type]) > 0) { delta = MIN(zfs_refcount_count(&arc_mfu->arcs_esize[type]), adjustmnt); total_evicted += arc_evict_impl(arc_mfu, 0, delta, type); } adjustmnt = meta_used - arc_meta_limit; if (adjustmnt > 0 && zfs_refcount_count(&arc_mru_ghost->arcs_esize[type]) > 0) { delta = MIN(adjustmnt, zfs_refcount_count(&arc_mru_ghost->arcs_esize[type])); total_evicted += arc_evict_impl(arc_mru_ghost, 0, delta, type); adjustmnt -= delta; } if (adjustmnt > 0 && zfs_refcount_count(&arc_mfu_ghost->arcs_esize[type]) > 0) { delta = MIN(adjustmnt, zfs_refcount_count(&arc_mfu_ghost->arcs_esize[type])); total_evicted += arc_evict_impl(arc_mfu_ghost, 0, delta, type); } /* * If after attempting to make the requested adjustment to the ARC * the meta limit is still being exceeded then request that the * higher layers drop some cached objects which have holds on ARC * meta buffers. Requests to the upper layers will be made with * increasingly large scan sizes until the ARC is below the limit. */ if (meta_used > arc_meta_limit) { if (type == ARC_BUFC_DATA) { type = ARC_BUFC_METADATA; } else { type = ARC_BUFC_DATA; if (zfs_arc_meta_prune) { prune += zfs_arc_meta_prune; arc_prune_async(prune); } } if (restarts > 0) { restarts--; goto restart; } } return (total_evicted); } /* * Evict metadata buffers from the cache, such that arcstat_meta_used is * capped by the arc_meta_limit tunable. */ static uint64_t arc_evict_meta_only(uint64_t meta_used) { uint64_t total_evicted = 0; int64_t target; /* * If we're over the meta limit, we want to evict enough * metadata to get back under the meta limit. We don't want to * evict so much that we drop the MRU below arc_p, though. If * we're over the meta limit more than we're over arc_p, we * evict some from the MRU here, and some from the MFU below. */ target = MIN((int64_t)(meta_used - arc_meta_limit), (int64_t)(zfs_refcount_count(&arc_anon->arcs_size) + zfs_refcount_count(&arc_mru->arcs_size) - arc_p)); total_evicted += arc_evict_impl(arc_mru, 0, target, ARC_BUFC_METADATA); /* * Similar to the above, we want to evict enough bytes to get us * below the meta limit, but not so much as to drop us below the * space allotted to the MFU (which is defined as arc_c - arc_p). */ target = MIN((int64_t)(meta_used - arc_meta_limit), (int64_t)(zfs_refcount_count(&arc_mfu->arcs_size) - (arc_c - arc_p))); total_evicted += arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_METADATA); return (total_evicted); } static uint64_t arc_evict_meta(uint64_t meta_used) { if (zfs_arc_meta_strategy == ARC_STRATEGY_META_ONLY) return (arc_evict_meta_only(meta_used)); else return (arc_evict_meta_balanced(meta_used)); } /* * Return the type of the oldest buffer in the given arc state * * This function will select a random sublist of type ARC_BUFC_DATA and * a random sublist of type ARC_BUFC_METADATA. The tail of each sublist * is compared, and the type which contains the "older" buffer will be * returned. */ static arc_buf_contents_t arc_evict_type(arc_state_t *state) { multilist_t *data_ml = &state->arcs_list[ARC_BUFC_DATA]; multilist_t *meta_ml = &state->arcs_list[ARC_BUFC_METADATA]; int data_idx = multilist_get_random_index(data_ml); int meta_idx = multilist_get_random_index(meta_ml); multilist_sublist_t *data_mls; multilist_sublist_t *meta_mls; arc_buf_contents_t type; arc_buf_hdr_t *data_hdr; arc_buf_hdr_t *meta_hdr; /* * We keep the sublist lock until we're finished, to prevent * the headers from being destroyed via arc_evict_state(). */ data_mls = multilist_sublist_lock(data_ml, data_idx); meta_mls = multilist_sublist_lock(meta_ml, meta_idx); /* * These two loops are to ensure we skip any markers that * might be at the tail of the lists due to arc_evict_state(). */ for (data_hdr = multilist_sublist_tail(data_mls); data_hdr != NULL; data_hdr = multilist_sublist_prev(data_mls, data_hdr)) { if (data_hdr->b_spa != 0) break; } for (meta_hdr = multilist_sublist_tail(meta_mls); meta_hdr != NULL; meta_hdr = multilist_sublist_prev(meta_mls, meta_hdr)) { if (meta_hdr->b_spa != 0) break; } if (data_hdr == NULL && meta_hdr == NULL) { type = ARC_BUFC_DATA; } else if (data_hdr == NULL) { ASSERT3P(meta_hdr, !=, NULL); type = ARC_BUFC_METADATA; } else if (meta_hdr == NULL) { ASSERT3P(data_hdr, !=, NULL); type = ARC_BUFC_DATA; } else { ASSERT3P(data_hdr, !=, NULL); ASSERT3P(meta_hdr, !=, NULL); /* The headers can't be on the sublist without an L1 header */ ASSERT(HDR_HAS_L1HDR(data_hdr)); ASSERT(HDR_HAS_L1HDR(meta_hdr)); if (data_hdr->b_l1hdr.b_arc_access < meta_hdr->b_l1hdr.b_arc_access) { type = ARC_BUFC_DATA; } else { type = ARC_BUFC_METADATA; } } multilist_sublist_unlock(meta_mls); multilist_sublist_unlock(data_mls); return (type); } /* * Evict buffers from the cache, such that arcstat_size is capped by arc_c. */ static uint64_t arc_evict(void) { uint64_t total_evicted = 0; uint64_t bytes; int64_t target; uint64_t asize = aggsum_value(&arc_sums.arcstat_size); uint64_t ameta = aggsum_value(&arc_sums.arcstat_meta_used); /* * If we're over arc_meta_limit, we want to correct that before * potentially evicting data buffers below. */ total_evicted += arc_evict_meta(ameta); /* * Adjust MRU size * * If we're over the target cache size, we want to evict enough * from the list to get back to our target size. We don't want * to evict too much from the MRU, such that it drops below * arc_p. So, if we're over our target cache size more than * the MRU is over arc_p, we'll evict enough to get back to * arc_p here, and then evict more from the MFU below. */ target = MIN((int64_t)(asize - arc_c), (int64_t)(zfs_refcount_count(&arc_anon->arcs_size) + zfs_refcount_count(&arc_mru->arcs_size) + ameta - arc_p)); /* * If we're below arc_meta_min, always prefer to evict data. * Otherwise, try to satisfy the requested number of bytes to * evict from the type which contains older buffers; in an * effort to keep newer buffers in the cache regardless of their * type. If we cannot satisfy the number of bytes from this * type, spill over into the next type. */ if (arc_evict_type(arc_mru) == ARC_BUFC_METADATA && ameta > arc_meta_min) { bytes = arc_evict_impl(arc_mru, 0, target, ARC_BUFC_METADATA); total_evicted += bytes; /* * If we couldn't evict our target number of bytes from * metadata, we try to get the rest from data. */ target -= bytes; total_evicted += arc_evict_impl(arc_mru, 0, target, ARC_BUFC_DATA); } else { bytes = arc_evict_impl(arc_mru, 0, target, ARC_BUFC_DATA); total_evicted += bytes; /* * If we couldn't evict our target number of bytes from * data, we try to get the rest from metadata. */ target -= bytes; total_evicted += arc_evict_impl(arc_mru, 0, target, ARC_BUFC_METADATA); } /* * Re-sum ARC stats after the first round of evictions. */ asize = aggsum_value(&arc_sums.arcstat_size); ameta = aggsum_value(&arc_sums.arcstat_meta_used); /* * Adjust MFU size * * Now that we've tried to evict enough from the MRU to get its * size back to arc_p, if we're still above the target cache * size, we evict the rest from the MFU. */ target = asize - arc_c; if (arc_evict_type(arc_mfu) == ARC_BUFC_METADATA && ameta > arc_meta_min) { bytes = arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_METADATA); total_evicted += bytes; /* * If we couldn't evict our target number of bytes from * metadata, we try to get the rest from data. */ target -= bytes; total_evicted += arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_DATA); } else { bytes = arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_DATA); total_evicted += bytes; /* * If we couldn't evict our target number of bytes from * data, we try to get the rest from data. */ target -= bytes; total_evicted += arc_evict_impl(arc_mfu, 0, target, ARC_BUFC_METADATA); } /* * Adjust ghost lists * * In addition to the above, the ARC also defines target values * for the ghost lists. The sum of the mru list and mru ghost * list should never exceed the target size of the cache, and * the sum of the mru list, mfu list, mru ghost list, and mfu * ghost list should never exceed twice the target size of the * cache. The following logic enforces these limits on the ghost * caches, and evicts from them as needed. */ target = zfs_refcount_count(&arc_mru->arcs_size) + zfs_refcount_count(&arc_mru_ghost->arcs_size) - arc_c; bytes = arc_evict_impl(arc_mru_ghost, 0, target, ARC_BUFC_DATA); total_evicted += bytes; target -= bytes; total_evicted += arc_evict_impl(arc_mru_ghost, 0, target, ARC_BUFC_METADATA); /* * We assume the sum of the mru list and mfu list is less than * or equal to arc_c (we enforced this above), which means we * can use the simpler of the two equations below: * * mru + mfu + mru ghost + mfu ghost <= 2 * arc_c * mru ghost + mfu ghost <= arc_c */ target = zfs_refcount_count(&arc_mru_ghost->arcs_size) + zfs_refcount_count(&arc_mfu_ghost->arcs_size) - arc_c; bytes = arc_evict_impl(arc_mfu_ghost, 0, target, ARC_BUFC_DATA); total_evicted += bytes; target -= bytes; total_evicted += arc_evict_impl(arc_mfu_ghost, 0, target, ARC_BUFC_METADATA); return (total_evicted); } void arc_flush(spa_t *spa, boolean_t retry) { uint64_t guid = 0; /* * If retry is B_TRUE, a spa must not be specified since we have * no good way to determine if all of a spa's buffers have been * evicted from an arc state. */ ASSERT(!retry || spa == 0); if (spa != NULL) guid = spa_load_guid(spa); (void) arc_flush_state(arc_mru, guid, ARC_BUFC_DATA, retry); (void) arc_flush_state(arc_mru, guid, ARC_BUFC_METADATA, retry); (void) arc_flush_state(arc_mfu, guid, ARC_BUFC_DATA, retry); (void) arc_flush_state(arc_mfu, guid, ARC_BUFC_METADATA, retry); (void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_DATA, retry); (void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_METADATA, retry); (void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_DATA, retry); (void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_METADATA, retry); } void arc_reduce_target_size(int64_t to_free) { uint64_t asize = aggsum_value(&arc_sums.arcstat_size); /* * All callers want the ARC to actually evict (at least) this much * memory. Therefore we reduce from the lower of the current size and * the target size. This way, even if arc_c is much higher than * arc_size (as can be the case after many calls to arc_freed(), we will * immediately have arc_c < arc_size and therefore the arc_evict_zthr * will evict. */ uint64_t c = MIN(arc_c, asize); if (c > to_free && c - to_free > arc_c_min) { arc_c = c - to_free; atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift)); if (arc_p > arc_c) arc_p = (arc_c >> 1); ASSERT(arc_c >= arc_c_min); ASSERT((int64_t)arc_p >= 0); } else { arc_c = arc_c_min; } if (asize > arc_c) { /* See comment in arc_evict_cb_check() on why lock+flag */ mutex_enter(&arc_evict_lock); arc_evict_needed = B_TRUE; mutex_exit(&arc_evict_lock); zthr_wakeup(arc_evict_zthr); } } /* * Determine if the system is under memory pressure and is asking * to reclaim memory. A return value of B_TRUE indicates that the system * is under memory pressure and that the arc should adjust accordingly. */ boolean_t arc_reclaim_needed(void) { return (arc_available_memory() < 0); } void arc_kmem_reap_soon(void) { size_t i; kmem_cache_t *prev_cache = NULL; kmem_cache_t *prev_data_cache = NULL; #ifdef _KERNEL if ((aggsum_compare(&arc_sums.arcstat_meta_used, arc_meta_limit) >= 0) && zfs_arc_meta_prune) { /* * We are exceeding our meta-data cache limit. * Prune some entries to release holds on meta-data. */ arc_prune_async(zfs_arc_meta_prune); } #if defined(_ILP32) /* * Reclaim unused memory from all kmem caches. */ kmem_reap(); #endif #endif for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { #if defined(_ILP32) /* reach upper limit of cache size on 32-bit */ if (zio_buf_cache[i] == NULL) break; #endif if (zio_buf_cache[i] != prev_cache) { prev_cache = zio_buf_cache[i]; kmem_cache_reap_now(zio_buf_cache[i]); } if (zio_data_buf_cache[i] != prev_data_cache) { prev_data_cache = zio_data_buf_cache[i]; kmem_cache_reap_now(zio_data_buf_cache[i]); } } kmem_cache_reap_now(buf_cache); kmem_cache_reap_now(hdr_full_cache); kmem_cache_reap_now(hdr_l2only_cache); kmem_cache_reap_now(zfs_btree_leaf_cache); abd_cache_reap_now(); } static boolean_t arc_evict_cb_check(void *arg, zthr_t *zthr) { (void) arg, (void) zthr; #ifdef ZFS_DEBUG /* * This is necessary in order to keep the kstat information * up to date for tools that display kstat data such as the * mdb ::arc dcmd and the Linux crash utility. These tools * typically do not call kstat's update function, but simply * dump out stats from the most recent update. Without * this call, these commands may show stale stats for the * anon, mru, mru_ghost, mfu, and mfu_ghost lists. Even * with this call, the data might be out of date if the * evict thread hasn't been woken recently; but that should * suffice. The arc_state_t structures can be queried * directly if more accurate information is needed. */ if (arc_ksp != NULL) arc_ksp->ks_update(arc_ksp, KSTAT_READ); #endif /* * We have to rely on arc_wait_for_eviction() to tell us when to * evict, rather than checking if we are overflowing here, so that we * are sure to not leave arc_wait_for_eviction() waiting on aew_cv. * If we have become "not overflowing" since arc_wait_for_eviction() * checked, we need to wake it up. We could broadcast the CV here, * but arc_wait_for_eviction() may have not yet gone to sleep. We * would need to use a mutex to ensure that this function doesn't * broadcast until arc_wait_for_eviction() has gone to sleep (e.g. * the arc_evict_lock). However, the lock ordering of such a lock * would necessarily be incorrect with respect to the zthr_lock, * which is held before this function is called, and is held by * arc_wait_for_eviction() when it calls zthr_wakeup(). */ return (arc_evict_needed); } /* * Keep arc_size under arc_c by running arc_evict which evicts data * from the ARC. */ static void arc_evict_cb(void *arg, zthr_t *zthr) { (void) arg, (void) zthr; uint64_t evicted = 0; fstrans_cookie_t cookie = spl_fstrans_mark(); /* Evict from cache */ evicted = arc_evict(); /* * If evicted is zero, we couldn't evict anything * via arc_evict(). This could be due to hash lock * collisions, but more likely due to the majority of * arc buffers being unevictable. Therefore, even if * arc_size is above arc_c, another pass is unlikely to * be helpful and could potentially cause us to enter an * infinite loop. Additionally, zthr_iscancelled() is * checked here so that if the arc is shutting down, the * broadcast will wake any remaining arc evict waiters. */ mutex_enter(&arc_evict_lock); arc_evict_needed = !zthr_iscancelled(arc_evict_zthr) && evicted > 0 && aggsum_compare(&arc_sums.arcstat_size, arc_c) > 0; if (!arc_evict_needed) { /* * We're either no longer overflowing, or we * can't evict anything more, so we should wake * arc_get_data_impl() sooner. */ arc_evict_waiter_t *aw; while ((aw = list_remove_head(&arc_evict_waiters)) != NULL) { cv_broadcast(&aw->aew_cv); } arc_set_need_free(); } mutex_exit(&arc_evict_lock); spl_fstrans_unmark(cookie); } static boolean_t arc_reap_cb_check(void *arg, zthr_t *zthr) { (void) arg, (void) zthr; int64_t free_memory = arc_available_memory(); static int reap_cb_check_counter = 0; /* * If a kmem reap is already active, don't schedule more. We must * check for this because kmem_cache_reap_soon() won't actually * block on the cache being reaped (this is to prevent callers from * becoming implicitly blocked by a system-wide kmem reap -- which, * on a system with many, many full magazines, can take minutes). */ if (!kmem_cache_reap_active() && free_memory < 0) { arc_no_grow = B_TRUE; arc_warm = B_TRUE; /* * Wait at least zfs_grow_retry (default 5) seconds * before considering growing. */ arc_growtime = gethrtime() + SEC2NSEC(arc_grow_retry); return (B_TRUE); } else if (free_memory < arc_c >> arc_no_grow_shift) { arc_no_grow = B_TRUE; } else if (gethrtime() >= arc_growtime) { arc_no_grow = B_FALSE; } /* * Called unconditionally every 60 seconds to reclaim unused * zstd compression and decompression context. This is done * here to avoid the need for an independent thread. */ if (!((reap_cb_check_counter++) % 60)) zfs_zstd_cache_reap_now(); return (B_FALSE); } /* * Keep enough free memory in the system by reaping the ARC's kmem * caches. To cause more slabs to be reapable, we may reduce the * target size of the cache (arc_c), causing the arc_evict_cb() * to free more buffers. */ static void arc_reap_cb(void *arg, zthr_t *zthr) { (void) arg, (void) zthr; int64_t free_memory; fstrans_cookie_t cookie = spl_fstrans_mark(); /* * Kick off asynchronous kmem_reap()'s of all our caches. */ arc_kmem_reap_soon(); /* * Wait at least arc_kmem_cache_reap_retry_ms between * arc_kmem_reap_soon() calls. Without this check it is possible to * end up in a situation where we spend lots of time reaping * caches, while we're near arc_c_min. Waiting here also gives the * subsequent free memory check a chance of finding that the * asynchronous reap has already freed enough memory, and we don't * need to call arc_reduce_target_size(). */ delay((hz * arc_kmem_cache_reap_retry_ms + 999) / 1000); /* * Reduce the target size as needed to maintain the amount of free * memory in the system at a fraction of the arc_size (1/128th by * default). If oversubscribed (free_memory < 0) then reduce the * target arc_size by the deficit amount plus the fractional * amount. If free memory is positive but less than the fractional * amount, reduce by what is needed to hit the fractional amount. */ free_memory = arc_available_memory(); int64_t can_free = arc_c - arc_c_min; if (can_free > 0) { int64_t to_free = (can_free >> arc_shrink_shift) - free_memory; if (to_free > 0) arc_reduce_target_size(to_free); } spl_fstrans_unmark(cookie); } #ifdef _KERNEL /* * Determine the amount of memory eligible for eviction contained in the * ARC. All clean data reported by the ghost lists can always be safely * evicted. Due to arc_c_min, the same does not hold for all clean data * contained by the regular mru and mfu lists. * * In the case of the regular mru and mfu lists, we need to report as * much clean data as possible, such that evicting that same reported * data will not bring arc_size below arc_c_min. Thus, in certain * circumstances, the total amount of clean data in the mru and mfu * lists might not actually be evictable. * * The following two distinct cases are accounted for: * * 1. The sum of the amount of dirty data contained by both the mru and * mfu lists, plus the ARC's other accounting (e.g. the anon list), * is greater than or equal to arc_c_min. * (i.e. amount of dirty data >= arc_c_min) * * This is the easy case; all clean data contained by the mru and mfu * lists is evictable. Evicting all clean data can only drop arc_size * to the amount of dirty data, which is greater than arc_c_min. * * 2. The sum of the amount of dirty data contained by both the mru and * mfu lists, plus the ARC's other accounting (e.g. the anon list), * is less than arc_c_min. * (i.e. arc_c_min > amount of dirty data) * * 2.1. arc_size is greater than or equal arc_c_min. * (i.e. arc_size >= arc_c_min > amount of dirty data) * * In this case, not all clean data from the regular mru and mfu * lists is actually evictable; we must leave enough clean data * to keep arc_size above arc_c_min. Thus, the maximum amount of * evictable data from the two lists combined, is exactly the * difference between arc_size and arc_c_min. * * 2.2. arc_size is less than arc_c_min * (i.e. arc_c_min > arc_size > amount of dirty data) * * In this case, none of the data contained in the mru and mfu * lists is evictable, even if it's clean. Since arc_size is * already below arc_c_min, evicting any more would only * increase this negative difference. */ #endif /* _KERNEL */ /* * Adapt arc info given the number of bytes we are trying to add and * the state that we are coming from. This function is only called * when we are adding new content to the cache. */ static void arc_adapt(int bytes, arc_state_t *state) { int mult; uint64_t arc_p_min = (arc_c >> arc_p_min_shift); int64_t mrug_size = zfs_refcount_count(&arc_mru_ghost->arcs_size); int64_t mfug_size = zfs_refcount_count(&arc_mfu_ghost->arcs_size); ASSERT(bytes > 0); /* * Adapt the target size of the MRU list: * - if we just hit in the MRU ghost list, then increase * the target size of the MRU list. * - if we just hit in the MFU ghost list, then increase * the target size of the MFU list by decreasing the * target size of the MRU list. */ if (state == arc_mru_ghost) { mult = (mrug_size >= mfug_size) ? 1 : (mfug_size / mrug_size); if (!zfs_arc_p_dampener_disable) mult = MIN(mult, 10); /* avoid wild arc_p adjustment */ arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); } else if (state == arc_mfu_ghost) { uint64_t delta; mult = (mfug_size >= mrug_size) ? 1 : (mrug_size / mfug_size); if (!zfs_arc_p_dampener_disable) mult = MIN(mult, 10); delta = MIN(bytes * mult, arc_p); arc_p = MAX(arc_p_min, arc_p - delta); } ASSERT((int64_t)arc_p >= 0); /* * Wake reap thread if we do not have any available memory */ if (arc_reclaim_needed()) { zthr_wakeup(arc_reap_zthr); return; } if (arc_no_grow) return; if (arc_c >= arc_c_max) return; /* * If we're within (2 * maxblocksize) bytes of the target * cache size, increment the target cache size */ ASSERT3U(arc_c, >=, 2ULL << SPA_MAXBLOCKSHIFT); if (aggsum_upper_bound(&arc_sums.arcstat_size) >= arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) { atomic_add_64(&arc_c, (int64_t)bytes); if (arc_c > arc_c_max) arc_c = arc_c_max; else if (state == arc_anon) atomic_add_64(&arc_p, (int64_t)bytes); if (arc_p > arc_c) arc_p = arc_c; } ASSERT((int64_t)arc_p >= 0); } /* * Check if arc_size has grown past our upper threshold, determined by * zfs_arc_overflow_shift. */ static arc_ovf_level_t arc_is_overflowing(boolean_t use_reserve) { /* Always allow at least one block of overflow */ int64_t overflow = MAX(SPA_MAXBLOCKSIZE, arc_c >> zfs_arc_overflow_shift); /* * We just compare the lower bound here for performance reasons. Our * primary goals are to make sure that the arc never grows without * bound, and that it can reach its maximum size. This check * accomplishes both goals. The maximum amount we could run over by is * 2 * aggsum_borrow_multiplier * NUM_CPUS * the average size of a block * in the ARC. In practice, that's in the tens of MB, which is low * enough to be safe. */ int64_t over = aggsum_lower_bound(&arc_sums.arcstat_size) - arc_c - overflow / 2; if (!use_reserve) overflow /= 2; return (over < 0 ? ARC_OVF_NONE : over < overflow ? ARC_OVF_SOME : ARC_OVF_SEVERE); } static abd_t * arc_get_data_abd(arc_buf_hdr_t *hdr, uint64_t size, const void *tag, int alloc_flags) { arc_buf_contents_t type = arc_buf_type(hdr); arc_get_data_impl(hdr, size, tag, alloc_flags); if (type == ARC_BUFC_METADATA) { return (abd_alloc(size, B_TRUE)); } else { ASSERT(type == ARC_BUFC_DATA); return (abd_alloc(size, B_FALSE)); } } static void * arc_get_data_buf(arc_buf_hdr_t *hdr, uint64_t size, const void *tag) { arc_buf_contents_t type = arc_buf_type(hdr); arc_get_data_impl(hdr, size, tag, ARC_HDR_DO_ADAPT); if (type == ARC_BUFC_METADATA) { return (zio_buf_alloc(size)); } else { ASSERT(type == ARC_BUFC_DATA); return (zio_data_buf_alloc(size)); } } /* * Wait for the specified amount of data (in bytes) to be evicted from the * ARC, and for there to be sufficient free memory in the system. Waiting for * eviction ensures that the memory used by the ARC decreases. Waiting for * free memory ensures that the system won't run out of free pages, regardless * of ARC behavior and settings. See arc_lowmem_init(). */ void arc_wait_for_eviction(uint64_t amount, boolean_t use_reserve) { switch (arc_is_overflowing(use_reserve)) { case ARC_OVF_NONE: return; case ARC_OVF_SOME: /* * This is a bit racy without taking arc_evict_lock, but the * worst that can happen is we either call zthr_wakeup() extra * time due to race with other thread here, or the set flag * get cleared by arc_evict_cb(), which is unlikely due to * big hysteresis, but also not important since at this level * of overflow the eviction is purely advisory. Same time * taking the global lock here every time without waiting for * the actual eviction creates a significant lock contention. */ if (!arc_evict_needed) { arc_evict_needed = B_TRUE; zthr_wakeup(arc_evict_zthr); } return; case ARC_OVF_SEVERE: default: { arc_evict_waiter_t aw; list_link_init(&aw.aew_node); cv_init(&aw.aew_cv, NULL, CV_DEFAULT, NULL); uint64_t last_count = 0; mutex_enter(&arc_evict_lock); if (!list_is_empty(&arc_evict_waiters)) { arc_evict_waiter_t *last = list_tail(&arc_evict_waiters); last_count = last->aew_count; } else if (!arc_evict_needed) { arc_evict_needed = B_TRUE; zthr_wakeup(arc_evict_zthr); } /* * Note, the last waiter's count may be less than * arc_evict_count if we are low on memory in which * case arc_evict_state_impl() may have deferred * wakeups (but still incremented arc_evict_count). */ aw.aew_count = MAX(last_count, arc_evict_count) + amount; list_insert_tail(&arc_evict_waiters, &aw); arc_set_need_free(); DTRACE_PROBE3(arc__wait__for__eviction, uint64_t, amount, uint64_t, arc_evict_count, uint64_t, aw.aew_count); /* * We will be woken up either when arc_evict_count reaches * aew_count, or when the ARC is no longer overflowing and * eviction completes. * In case of "false" wakeup, we will still be on the list. */ do { cv_wait(&aw.aew_cv, &arc_evict_lock); } while (list_link_active(&aw.aew_node)); mutex_exit(&arc_evict_lock); cv_destroy(&aw.aew_cv); } } } /* * Allocate a block and return it to the caller. If we are hitting the * hard limit for the cache size, we must sleep, waiting for the eviction * thread to catch up. If we're past the target size but below the hard * limit, we'll only signal the reclaim thread and continue on. */ static void arc_get_data_impl(arc_buf_hdr_t *hdr, uint64_t size, const void *tag, int alloc_flags) { arc_state_t *state = hdr->b_l1hdr.b_state; arc_buf_contents_t type = arc_buf_type(hdr); if (alloc_flags & ARC_HDR_DO_ADAPT) arc_adapt(size, state); /* * If arc_size is currently overflowing, we must be adding data * faster than we are evicting. To ensure we don't compound the * problem by adding more data and forcing arc_size to grow even * further past it's target size, we wait for the eviction thread to * make some progress. We also wait for there to be sufficient free * memory in the system, as measured by arc_free_memory(). * * Specifically, we wait for zfs_arc_eviction_pct percent of the * requested size to be evicted. This should be more than 100%, to * ensure that that progress is also made towards getting arc_size * under arc_c. See the comment above zfs_arc_eviction_pct. */ arc_wait_for_eviction(size * zfs_arc_eviction_pct / 100, alloc_flags & ARC_HDR_USE_RESERVE); VERIFY3U(hdr->b_type, ==, type); if (type == ARC_BUFC_METADATA) { arc_space_consume(size, ARC_SPACE_META); } else { arc_space_consume(size, ARC_SPACE_DATA); } /* * Update the state size. Note that ghost states have a * "ghost size" and so don't need to be updated. */ if (!GHOST_STATE(state)) { (void) zfs_refcount_add_many(&state->arcs_size, size, tag); /* * If this is reached via arc_read, the link is * protected by the hash lock. If reached via * arc_buf_alloc, the header should not be accessed by * any other thread. And, if reached via arc_read_done, * the hash lock will protect it if it's found in the * hash table; otherwise no other thread should be * trying to [add|remove]_reference it. */ if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) { ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); (void) zfs_refcount_add_many(&state->arcs_esize[type], size, tag); } /* * If we are growing the cache, and we are adding anonymous * data, and we have outgrown arc_p, update arc_p */ if (aggsum_upper_bound(&arc_sums.arcstat_size) < arc_c && hdr->b_l1hdr.b_state == arc_anon && (zfs_refcount_count(&arc_anon->arcs_size) + zfs_refcount_count(&arc_mru->arcs_size) > arc_p)) arc_p = MIN(arc_c, arc_p + size); } } static void arc_free_data_abd(arc_buf_hdr_t *hdr, abd_t *abd, uint64_t size, const void *tag) { arc_free_data_impl(hdr, size, tag); abd_free(abd); } static void arc_free_data_buf(arc_buf_hdr_t *hdr, void *buf, uint64_t size, const void *tag) { arc_buf_contents_t type = arc_buf_type(hdr); arc_free_data_impl(hdr, size, tag); if (type == ARC_BUFC_METADATA) { zio_buf_free(buf, size); } else { ASSERT(type == ARC_BUFC_DATA); zio_data_buf_free(buf, size); } } /* * Free the arc data buffer. */ static void arc_free_data_impl(arc_buf_hdr_t *hdr, uint64_t size, const void *tag) { arc_state_t *state = hdr->b_l1hdr.b_state; arc_buf_contents_t type = arc_buf_type(hdr); /* protected by hash lock, if in the hash table */ if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) { ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); ASSERT(state != arc_anon && state != arc_l2c_only); (void) zfs_refcount_remove_many(&state->arcs_esize[type], size, tag); } (void) zfs_refcount_remove_many(&state->arcs_size, size, tag); VERIFY3U(hdr->b_type, ==, type); if (type == ARC_BUFC_METADATA) { arc_space_return(size, ARC_SPACE_META); } else { ASSERT(type == ARC_BUFC_DATA); arc_space_return(size, ARC_SPACE_DATA); } } /* * This routine is called whenever a buffer is accessed. * NOTE: the hash lock is dropped in this function. */ static void arc_access(arc_buf_hdr_t *hdr, kmutex_t *hash_lock) { clock_t now; ASSERT(MUTEX_HELD(hash_lock)); ASSERT(HDR_HAS_L1HDR(hdr)); if (hdr->b_l1hdr.b_state == arc_anon) { /* * This buffer is not in the cache, and does not * appear in our "ghost" list. Add the new buffer * to the MRU state. */ ASSERT0(hdr->b_l1hdr.b_arc_access); hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr); arc_change_state(arc_mru, hdr, hash_lock); } else if (hdr->b_l1hdr.b_state == arc_mru) { now = ddi_get_lbolt(); /* * If this buffer is here because of a prefetch, then either: * - clear the flag if this is a "referencing" read * (any subsequent access will bump this into the MFU state). * or * - move the buffer to the head of the list if this is * another prefetch (to make it less likely to be evicted). */ if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) { if (zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 0) { /* link protected by hash lock */ ASSERT(multilist_link_active( &hdr->b_l1hdr.b_arc_node)); } else { if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_decrement_state(hdr); arc_hdr_clear_flags(hdr, ARC_FLAG_PREFETCH | ARC_FLAG_PRESCIENT_PREFETCH); hdr->b_l1hdr.b_mru_hits++; ARCSTAT_BUMP(arcstat_mru_hits); if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_increment_state(hdr); } hdr->b_l1hdr.b_arc_access = now; return; } /* * This buffer has been "accessed" only once so far, * but it is still in the cache. Move it to the MFU * state. */ if (ddi_time_after(now, hdr->b_l1hdr.b_arc_access + ARC_MINTIME)) { /* * More than 125ms have passed since we * instantiated this buffer. Move it to the * most frequently used state. */ hdr->b_l1hdr.b_arc_access = now; DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); arc_change_state(arc_mfu, hdr, hash_lock); } hdr->b_l1hdr.b_mru_hits++; ARCSTAT_BUMP(arcstat_mru_hits); } else if (hdr->b_l1hdr.b_state == arc_mru_ghost) { arc_state_t *new_state; /* * This buffer has been "accessed" recently, but * was evicted from the cache. Move it to the * MFU state. */ if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) { new_state = arc_mru; if (zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) > 0) { if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_decrement_state(hdr); arc_hdr_clear_flags(hdr, ARC_FLAG_PREFETCH | ARC_FLAG_PRESCIENT_PREFETCH); if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_increment_state(hdr); } DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr); } else { new_state = arc_mfu; DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); } hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); arc_change_state(new_state, hdr, hash_lock); hdr->b_l1hdr.b_mru_ghost_hits++; ARCSTAT_BUMP(arcstat_mru_ghost_hits); } else if (hdr->b_l1hdr.b_state == arc_mfu) { /* * This buffer has been accessed more than once and is * still in the cache. Keep it in the MFU state. * * NOTE: an add_reference() that occurred when we did * the arc_read() will have kicked this off the list. * If it was a prefetch, we will explicitly move it to * the head of the list now. */ hdr->b_l1hdr.b_mfu_hits++; ARCSTAT_BUMP(arcstat_mfu_hits); hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); } else if (hdr->b_l1hdr.b_state == arc_mfu_ghost) { arc_state_t *new_state = arc_mfu; /* * This buffer has been accessed more than once but has * been evicted from the cache. Move it back to the * MFU state. */ if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) { /* * This is a prefetch access... * move this block back to the MRU state. */ new_state = arc_mru; } hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); arc_change_state(new_state, hdr, hash_lock); hdr->b_l1hdr.b_mfu_ghost_hits++; ARCSTAT_BUMP(arcstat_mfu_ghost_hits); } else if (hdr->b_l1hdr.b_state == arc_l2c_only) { /* * This buffer is on the 2nd Level ARC. */ hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); arc_change_state(arc_mfu, hdr, hash_lock); } else { cmn_err(CE_PANIC, "invalid arc state 0x%p", hdr->b_l1hdr.b_state); } } /* * This routine is called by dbuf_hold() to update the arc_access() state * which otherwise would be skipped for entries in the dbuf cache. */ void arc_buf_access(arc_buf_t *buf) { mutex_enter(&buf->b_evict_lock); arc_buf_hdr_t *hdr = buf->b_hdr; /* * Avoid taking the hash_lock when possible as an optimization. * The header must be checked again under the hash_lock in order * to handle the case where it is concurrently being released. */ if (hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY(hdr)) { mutex_exit(&buf->b_evict_lock); return; } kmutex_t *hash_lock = HDR_LOCK(hdr); mutex_enter(hash_lock); if (hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY(hdr)) { mutex_exit(hash_lock); mutex_exit(&buf->b_evict_lock); ARCSTAT_BUMP(arcstat_access_skip); return; } mutex_exit(&buf->b_evict_lock); ASSERT(hdr->b_l1hdr.b_state == arc_mru || hdr->b_l1hdr.b_state == arc_mfu); DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); arc_access(hdr, hash_lock); mutex_exit(hash_lock); ARCSTAT_BUMP(arcstat_hits); ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr) && !HDR_PRESCIENT_PREFETCH(hdr), demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data, metadata, hits); } /* a generic arc_read_done_func_t which you can use */ void arc_bcopy_func(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp, arc_buf_t *buf, void *arg) { (void) zio, (void) zb, (void) bp; if (buf == NULL) return; memcpy(arg, buf->b_data, arc_buf_size(buf)); arc_buf_destroy(buf, arg); } /* a generic arc_read_done_func_t */ void arc_getbuf_func(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp, arc_buf_t *buf, void *arg) { (void) zb, (void) bp; arc_buf_t **bufp = arg; if (buf == NULL) { ASSERT(zio == NULL || zio->io_error != 0); *bufp = NULL; } else { ASSERT(zio == NULL || zio->io_error == 0); *bufp = buf; ASSERT(buf->b_data != NULL); } } static void arc_hdr_verify(arc_buf_hdr_t *hdr, blkptr_t *bp) { if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) { ASSERT3U(HDR_GET_PSIZE(hdr), ==, 0); ASSERT3U(arc_hdr_get_compress(hdr), ==, ZIO_COMPRESS_OFF); } else { if (HDR_COMPRESSION_ENABLED(hdr)) { ASSERT3U(arc_hdr_get_compress(hdr), ==, BP_GET_COMPRESS(bp)); } ASSERT3U(HDR_GET_LSIZE(hdr), ==, BP_GET_LSIZE(bp)); ASSERT3U(HDR_GET_PSIZE(hdr), ==, BP_GET_PSIZE(bp)); ASSERT3U(!!HDR_PROTECTED(hdr), ==, BP_IS_PROTECTED(bp)); } } static void arc_read_done(zio_t *zio) { blkptr_t *bp = zio->io_bp; arc_buf_hdr_t *hdr = zio->io_private; kmutex_t *hash_lock = NULL; arc_callback_t *callback_list; arc_callback_t *acb; boolean_t freeable = B_FALSE; /* * The hdr was inserted into hash-table and removed from lists * prior to starting I/O. We should find this header, since * it's in the hash table, and it should be legit since it's * not possible to evict it during the I/O. The only possible * reason for it not to be found is if we were freed during the * read. */ if (HDR_IN_HASH_TABLE(hdr)) { arc_buf_hdr_t *found; ASSERT3U(hdr->b_birth, ==, BP_PHYSICAL_BIRTH(zio->io_bp)); ASSERT3U(hdr->b_dva.dva_word[0], ==, BP_IDENTITY(zio->io_bp)->dva_word[0]); ASSERT3U(hdr->b_dva.dva_word[1], ==, BP_IDENTITY(zio->io_bp)->dva_word[1]); found = buf_hash_find(hdr->b_spa, zio->io_bp, &hash_lock); ASSERT((found == hdr && DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || (found == hdr && HDR_L2_READING(hdr))); ASSERT3P(hash_lock, !=, NULL); } if (BP_IS_PROTECTED(bp)) { hdr->b_crypt_hdr.b_ot = BP_GET_TYPE(bp); hdr->b_crypt_hdr.b_dsobj = zio->io_bookmark.zb_objset; zio_crypt_decode_params_bp(bp, hdr->b_crypt_hdr.b_salt, hdr->b_crypt_hdr.b_iv); if (zio->io_error == 0) { if (BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG) { void *tmpbuf; tmpbuf = abd_borrow_buf_copy(zio->io_abd, sizeof (zil_chain_t)); zio_crypt_decode_mac_zil(tmpbuf, hdr->b_crypt_hdr.b_mac); abd_return_buf(zio->io_abd, tmpbuf, sizeof (zil_chain_t)); } else { zio_crypt_decode_mac_bp(bp, hdr->b_crypt_hdr.b_mac); } } } if (zio->io_error == 0) { /* byteswap if necessary */ if (BP_SHOULD_BYTESWAP(zio->io_bp)) { if (BP_GET_LEVEL(zio->io_bp) > 0) { hdr->b_l1hdr.b_byteswap = DMU_BSWAP_UINT64; } else { hdr->b_l1hdr.b_byteswap = DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp)); } } else { hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; } if (!HDR_L2_READING(hdr)) { hdr->b_complevel = zio->io_prop.zp_complevel; } } arc_hdr_clear_flags(hdr, ARC_FLAG_L2_EVICTED); if (l2arc_noprefetch && HDR_PREFETCH(hdr)) arc_hdr_clear_flags(hdr, ARC_FLAG_L2CACHE); callback_list = hdr->b_l1hdr.b_acb; ASSERT3P(callback_list, !=, NULL); if (hash_lock && zio->io_error == 0 && hdr->b_l1hdr.b_state == arc_anon) { /* * Only call arc_access on anonymous buffers. This is because * if we've issued an I/O for an evicted buffer, we've already * called arc_access (to prevent any simultaneous readers from * getting confused). */ arc_access(hdr, hash_lock); } /* * If a read request has a callback (i.e. acb_done is not NULL), then we * make a buf containing the data according to the parameters which were * passed in. The implementation of arc_buf_alloc_impl() ensures that we * aren't needlessly decompressing the data multiple times. */ int callback_cnt = 0; for (acb = callback_list; acb != NULL; acb = acb->acb_next) { if (!acb->acb_done || acb->acb_nobuf) continue; callback_cnt++; if (zio->io_error != 0) continue; int error = arc_buf_alloc_impl(hdr, zio->io_spa, &acb->acb_zb, acb->acb_private, acb->acb_encrypted, acb->acb_compressed, acb->acb_noauth, B_TRUE, &acb->acb_buf); /* * Assert non-speculative zios didn't fail because an * encryption key wasn't loaded */ ASSERT((zio->io_flags & ZIO_FLAG_SPECULATIVE) || error != EACCES); /* * If we failed to decrypt, report an error now (as the zio * layer would have done if it had done the transforms). */ if (error == ECKSUM) { ASSERT(BP_IS_PROTECTED(bp)); error = SET_ERROR(EIO); if ((zio->io_flags & ZIO_FLAG_SPECULATIVE) == 0) { spa_log_error(zio->io_spa, &acb->acb_zb); (void) zfs_ereport_post( FM_EREPORT_ZFS_AUTHENTICATION, zio->io_spa, NULL, &acb->acb_zb, zio, 0); } } if (error != 0) { /* * Decompression or decryption failed. Set * io_error so that when we call acb_done * (below), we will indicate that the read * failed. Note that in the unusual case * where one callback is compressed and another * uncompressed, we will mark all of them * as failed, even though the uncompressed * one can't actually fail. In this case, * the hdr will not be anonymous, because * if there are multiple callbacks, it's * because multiple threads found the same * arc buf in the hash table. */ zio->io_error = error; } } /* * If there are multiple callbacks, we must have the hash lock, * because the only way for multiple threads to find this hdr is * in the hash table. This ensures that if there are multiple * callbacks, the hdr is not anonymous. If it were anonymous, * we couldn't use arc_buf_destroy() in the error case below. */ ASSERT(callback_cnt < 2 || hash_lock != NULL); hdr->b_l1hdr.b_acb = NULL; arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); if (callback_cnt == 0) ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt) || callback_list != NULL); if (zio->io_error == 0) { arc_hdr_verify(hdr, zio->io_bp); } else { arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR); if (hdr->b_l1hdr.b_state != arc_anon) arc_change_state(arc_anon, hdr, hash_lock); if (HDR_IN_HASH_TABLE(hdr)) buf_hash_remove(hdr); freeable = zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt); } /* * Broadcast before we drop the hash_lock to avoid the possibility * that the hdr (and hence the cv) might be freed before we get to * the cv_broadcast(). */ cv_broadcast(&hdr->b_l1hdr.b_cv); if (hash_lock != NULL) { mutex_exit(hash_lock); } else { /* * This block was freed while we waited for the read to * complete. It has been removed from the hash table and * moved to the anonymous state (so that it won't show up * in the cache). */ ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); freeable = zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt); } /* execute each callback and free its structure */ while ((acb = callback_list) != NULL) { if (acb->acb_done != NULL) { if (zio->io_error != 0 && acb->acb_buf != NULL) { /* * If arc_buf_alloc_impl() fails during * decompression, the buf will still be * allocated, and needs to be freed here. */ arc_buf_destroy(acb->acb_buf, acb->acb_private); acb->acb_buf = NULL; } acb->acb_done(zio, &zio->io_bookmark, zio->io_bp, acb->acb_buf, acb->acb_private); } if (acb->acb_zio_dummy != NULL) { acb->acb_zio_dummy->io_error = zio->io_error; zio_nowait(acb->acb_zio_dummy); } callback_list = acb->acb_next; kmem_free(acb, sizeof (arc_callback_t)); } if (freeable) arc_hdr_destroy(hdr); } /* * "Read" the block at the specified DVA (in bp) via the * cache. If the block is found in the cache, invoke the provided * callback immediately and return. Note that the `zio' parameter * in the callback will be NULL in this case, since no IO was * required. If the block is not in the cache pass the read request * on to the spa with a substitute callback function, so that the * requested block will be added to the cache. * * If a read request arrives for a block that has a read in-progress, * either wait for the in-progress read to complete (and return the * results); or, if this is a read with a "done" func, add a record * to the read to invoke the "done" func when the read completes, * and return; or just return. * * arc_read_done() will invoke all the requested "done" functions * for readers of this block. */ int arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, arc_read_done_func_t *done, void *private, zio_priority_t priority, int zio_flags, arc_flags_t *arc_flags, const zbookmark_phys_t *zb) { arc_buf_hdr_t *hdr = NULL; kmutex_t *hash_lock = NULL; zio_t *rzio; uint64_t guid = spa_load_guid(spa); boolean_t compressed_read = (zio_flags & ZIO_FLAG_RAW_COMPRESS) != 0; boolean_t encrypted_read = BP_IS_ENCRYPTED(bp) && (zio_flags & ZIO_FLAG_RAW_ENCRYPT) != 0; boolean_t noauth_read = BP_IS_AUTHENTICATED(bp) && (zio_flags & ZIO_FLAG_RAW_ENCRYPT) != 0; boolean_t embedded_bp = !!BP_IS_EMBEDDED(bp); boolean_t no_buf = *arc_flags & ARC_FLAG_NO_BUF; int rc = 0; ASSERT(!embedded_bp || BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA); ASSERT(!BP_IS_HOLE(bp)); ASSERT(!BP_IS_REDACTED(bp)); /* * Normally SPL_FSTRANS will already be set since kernel threads which * expect to call the DMU interfaces will set it when created. System * calls are similarly handled by setting/cleaning the bit in the * registered callback (module/os/.../zfs/zpl_*). * * External consumers such as Lustre which call the exported DMU * interfaces may not have set SPL_FSTRANS. To avoid a deadlock * on the hash_lock always set and clear the bit. */ fstrans_cookie_t cookie = spl_fstrans_mark(); top: /* * Verify the block pointer contents are reasonable. This should * always be the case since the blkptr is protected by a checksum. * However, if there is damage it's desirable to detect this early * and treat it as a checksum error. This allows an alternate blkptr * to be tried when one is available (e.g. ditto blocks). */ if (!zfs_blkptr_verify(spa, bp, zio_flags & ZIO_FLAG_CONFIG_WRITER, BLK_VERIFY_LOG)) { rc = SET_ERROR(ECKSUM); goto out; } if (!embedded_bp) { /* * Embedded BP's have no DVA and require no I/O to "read". * Create an anonymous arc buf to back it. */ hdr = buf_hash_find(guid, bp, &hash_lock); } /* * Determine if we have an L1 cache hit or a cache miss. For simplicity * we maintain encrypted data separately from compressed / uncompressed * data. If the user is requesting raw encrypted data and we don't have * that in the header we will read from disk to guarantee that we can * get it even if the encryption keys aren't loaded. */ if (hdr != NULL && HDR_HAS_L1HDR(hdr) && (HDR_HAS_RABD(hdr) || (hdr->b_l1hdr.b_pabd != NULL && !encrypted_read))) { arc_buf_t *buf = NULL; *arc_flags |= ARC_FLAG_CACHED; if (HDR_IO_IN_PROGRESS(hdr)) { zio_t *head_zio = hdr->b_l1hdr.b_acb->acb_zio_head; if (*arc_flags & ARC_FLAG_CACHED_ONLY) { mutex_exit(hash_lock); ARCSTAT_BUMP(arcstat_cached_only_in_progress); rc = SET_ERROR(ENOENT); goto out; } ASSERT3P(head_zio, !=, NULL); if ((hdr->b_flags & ARC_FLAG_PRIO_ASYNC_READ) && priority == ZIO_PRIORITY_SYNC_READ) { /* * This is a sync read that needs to wait for * an in-flight async read. Request that the * zio have its priority upgraded. */ zio_change_priority(head_zio, priority); DTRACE_PROBE1(arc__async__upgrade__sync, arc_buf_hdr_t *, hdr); ARCSTAT_BUMP(arcstat_async_upgrade_sync); } if (hdr->b_flags & ARC_FLAG_PREDICTIVE_PREFETCH) { arc_hdr_clear_flags(hdr, ARC_FLAG_PREDICTIVE_PREFETCH); } /* * If there are multiple threads reading the same block * and that block is not yet in the ARC, then only one * thread will do the physical I/O and all other * threads will wait until that I/O completes. * Synchronous reads use the b_cv whereas nowait reads * register a callback. Both are signalled/called in * arc_read_done. * * Errors of the physical I/O may need to be propagated * to the pio. For synchronous reads, we simply restart * this function and it will reassess. Nowait reads * attach the acb_zio_dummy zio to pio and * arc_read_done propagates the physical I/O's io_error * to acb_zio_dummy, and thereby to pio. */ if (*arc_flags & ARC_FLAG_WAIT) { cv_wait(&hdr->b_l1hdr.b_cv, hash_lock); mutex_exit(hash_lock); goto top; } ASSERT(*arc_flags & ARC_FLAG_NOWAIT); if (done) { arc_callback_t *acb = NULL; acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP); acb->acb_done = done; acb->acb_private = private; acb->acb_compressed = compressed_read; acb->acb_encrypted = encrypted_read; acb->acb_noauth = noauth_read; acb->acb_nobuf = no_buf; acb->acb_zb = *zb; if (pio != NULL) acb->acb_zio_dummy = zio_null(pio, spa, NULL, NULL, NULL, zio_flags); ASSERT3P(acb->acb_done, !=, NULL); acb->acb_zio_head = head_zio; acb->acb_next = hdr->b_l1hdr.b_acb; hdr->b_l1hdr.b_acb = acb; } mutex_exit(hash_lock); goto out; } ASSERT(hdr->b_l1hdr.b_state == arc_mru || hdr->b_l1hdr.b_state == arc_mfu); if (done && !no_buf) { if (hdr->b_flags & ARC_FLAG_PREDICTIVE_PREFETCH) { /* * This is a demand read which does not have to * wait for i/o because we did a predictive * prefetch i/o for it, which has completed. */ DTRACE_PROBE1( arc__demand__hit__predictive__prefetch, arc_buf_hdr_t *, hdr); ARCSTAT_BUMP( arcstat_demand_hit_predictive_prefetch); arc_hdr_clear_flags(hdr, ARC_FLAG_PREDICTIVE_PREFETCH); } if (hdr->b_flags & ARC_FLAG_PRESCIENT_PREFETCH) { ARCSTAT_BUMP( arcstat_demand_hit_prescient_prefetch); arc_hdr_clear_flags(hdr, ARC_FLAG_PRESCIENT_PREFETCH); } ASSERT(!embedded_bp || !BP_IS_HOLE(bp)); /* Get a buf with the desired data in it. */ rc = arc_buf_alloc_impl(hdr, spa, zb, private, encrypted_read, compressed_read, noauth_read, B_TRUE, &buf); if (rc == ECKSUM) { /* * Convert authentication and decryption errors * to EIO (and generate an ereport if needed) * before leaving the ARC. */ rc = SET_ERROR(EIO); if ((zio_flags & ZIO_FLAG_SPECULATIVE) == 0) { spa_log_error(spa, zb); (void) zfs_ereport_post( FM_EREPORT_ZFS_AUTHENTICATION, spa, NULL, zb, NULL, 0); } } if (rc != 0) { (void) remove_reference(hdr, hash_lock, private); arc_buf_destroy_impl(buf); buf = NULL; } /* assert any errors weren't due to unloaded keys */ ASSERT((zio_flags & ZIO_FLAG_SPECULATIVE) || rc != EACCES); } else if (*arc_flags & ARC_FLAG_PREFETCH && zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)) { if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_decrement_state(hdr); arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH); if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_increment_state(hdr); } DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); arc_access(hdr, hash_lock); if (*arc_flags & ARC_FLAG_PRESCIENT_PREFETCH) arc_hdr_set_flags(hdr, ARC_FLAG_PRESCIENT_PREFETCH); if (*arc_flags & ARC_FLAG_L2CACHE) arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE); mutex_exit(hash_lock); ARCSTAT_BUMP(arcstat_hits); ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr), demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data, metadata, hits); if (done) done(NULL, zb, bp, buf, private); } else { uint64_t lsize = BP_GET_LSIZE(bp); uint64_t psize = BP_GET_PSIZE(bp); arc_callback_t *acb; vdev_t *vd = NULL; uint64_t addr = 0; boolean_t devw = B_FALSE; uint64_t size; abd_t *hdr_abd; int alloc_flags = encrypted_read ? ARC_HDR_ALLOC_RDATA : 0; if (*arc_flags & ARC_FLAG_CACHED_ONLY) { rc = SET_ERROR(ENOENT); if (hash_lock != NULL) mutex_exit(hash_lock); goto out; } if (hdr == NULL) { /* * This block is not in the cache or it has * embedded data. */ arc_buf_hdr_t *exists = NULL; arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize, BP_IS_PROTECTED(bp), BP_GET_COMPRESS(bp), 0, type); if (!embedded_bp) { hdr->b_dva = *BP_IDENTITY(bp); hdr->b_birth = BP_PHYSICAL_BIRTH(bp); exists = buf_hash_insert(hdr, &hash_lock); } if (exists != NULL) { /* somebody beat us to the hash insert */ mutex_exit(hash_lock); buf_discard_identity(hdr); arc_hdr_destroy(hdr); goto top; /* restart the IO request */ } alloc_flags |= ARC_HDR_DO_ADAPT; } else { /* * This block is in the ghost cache or encrypted data * was requested and we didn't have it. If it was * L2-only (and thus didn't have an L1 hdr), * we realloc the header to add an L1 hdr. */ if (!HDR_HAS_L1HDR(hdr)) { hdr = arc_hdr_realloc(hdr, hdr_l2only_cache, hdr_full_cache); } if (GHOST_STATE(hdr->b_l1hdr.b_state)) { ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); ASSERT(!HDR_IO_IN_PROGRESS(hdr)); ASSERT0(zfs_refcount_count( &hdr->b_l1hdr.b_refcnt)); ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); } else if (HDR_IO_IN_PROGRESS(hdr)) { /* * If this header already had an IO in progress * and we are performing another IO to fetch * encrypted data we must wait until the first * IO completes so as not to confuse * arc_read_done(). This should be very rare * and so the performance impact shouldn't * matter. */ cv_wait(&hdr->b_l1hdr.b_cv, hash_lock); mutex_exit(hash_lock); goto top; } /* * This is a delicate dance that we play here. * This hdr might be in the ghost list so we access * it to move it out of the ghost list before we * initiate the read. If it's a prefetch then * it won't have a callback so we'll remove the * reference that arc_buf_alloc_impl() created. We * do this after we've called arc_access() to * avoid hitting an assert in remove_reference(). */ arc_adapt(arc_hdr_size(hdr), hdr->b_l1hdr.b_state); arc_access(hdr, hash_lock); } arc_hdr_alloc_abd(hdr, alloc_flags); if (encrypted_read) { ASSERT(HDR_HAS_RABD(hdr)); size = HDR_GET_PSIZE(hdr); hdr_abd = hdr->b_crypt_hdr.b_rabd; zio_flags |= ZIO_FLAG_RAW; } else { ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); size = arc_hdr_size(hdr); hdr_abd = hdr->b_l1hdr.b_pabd; if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF) { zio_flags |= ZIO_FLAG_RAW_COMPRESS; } /* * For authenticated bp's, we do not ask the ZIO layer * to authenticate them since this will cause the entire * IO to fail if the key isn't loaded. Instead, we * defer authentication until arc_buf_fill(), which will * verify the data when the key is available. */ if (BP_IS_AUTHENTICATED(bp)) zio_flags |= ZIO_FLAG_RAW_ENCRYPT; } if (*arc_flags & ARC_FLAG_PREFETCH && zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)) { if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_decrement_state(hdr); arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH); if (HDR_HAS_L2HDR(hdr)) l2arc_hdr_arcstats_increment_state(hdr); } if (*arc_flags & ARC_FLAG_PRESCIENT_PREFETCH) arc_hdr_set_flags(hdr, ARC_FLAG_PRESCIENT_PREFETCH); if (*arc_flags & ARC_FLAG_L2CACHE) arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE); if (BP_IS_AUTHENTICATED(bp)) arc_hdr_set_flags(hdr, ARC_FLAG_NOAUTH); if (BP_GET_LEVEL(bp) > 0) arc_hdr_set_flags(hdr, ARC_FLAG_INDIRECT); if (*arc_flags & ARC_FLAG_PREDICTIVE_PREFETCH) arc_hdr_set_flags(hdr, ARC_FLAG_PREDICTIVE_PREFETCH); ASSERT(!GHOST_STATE(hdr->b_l1hdr.b_state)); acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP); acb->acb_done = done; acb->acb_private = private; acb->acb_compressed = compressed_read; acb->acb_encrypted = encrypted_read; acb->acb_noauth = noauth_read; acb->acb_zb = *zb; ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); hdr->b_l1hdr.b_acb = acb; arc_hdr_set_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); if (HDR_HAS_L2HDR(hdr) && (vd = hdr->b_l2hdr.b_dev->l2ad_vdev) != NULL) { devw = hdr->b_l2hdr.b_dev->l2ad_writing; addr = hdr->b_l2hdr.b_daddr; /* * Lock out L2ARC device removal. */ if (vdev_is_dead(vd) || !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) vd = NULL; } /* * We count both async reads and scrub IOs as asynchronous so * that both can be upgraded in the event of a cache hit while * the read IO is still in-flight. */ if (priority == ZIO_PRIORITY_ASYNC_READ || priority == ZIO_PRIORITY_SCRUB) arc_hdr_set_flags(hdr, ARC_FLAG_PRIO_ASYNC_READ); else arc_hdr_clear_flags(hdr, ARC_FLAG_PRIO_ASYNC_READ); /* * At this point, we have a level 1 cache miss or a blkptr * with embedded data. Try again in L2ARC if possible. */ ASSERT3U(HDR_GET_LSIZE(hdr), ==, lsize); /* * Skip ARC stat bump for block pointers with embedded * data. The data are read from the blkptr itself via * decode_embedded_bp_compressed(). */ if (!embedded_bp) { DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, blkptr_t *, bp, uint64_t, lsize, zbookmark_phys_t *, zb); ARCSTAT_BUMP(arcstat_misses); ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr), demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data, metadata, misses); zfs_racct_read(size, 1); } /* Check if the spa even has l2 configured */ const boolean_t spa_has_l2 = l2arc_ndev != 0 && spa->spa_l2cache.sav_count > 0; if (vd != NULL && spa_has_l2 && !(l2arc_norw && devw)) { /* * Read from the L2ARC if the following are true: * 1. The L2ARC vdev was previously cached. * 2. This buffer still has L2ARC metadata. * 3. This buffer isn't currently writing to the L2ARC. * 4. The L2ARC entry wasn't evicted, which may * also have invalidated the vdev. * 5. This isn't prefetch or l2arc_noprefetch is 0. */ if (HDR_HAS_L2HDR(hdr) && !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { l2arc_read_callback_t *cb; abd_t *abd; uint64_t asize; DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); ARCSTAT_BUMP(arcstat_l2_hits); hdr->b_l2hdr.b_hits++; cb = kmem_zalloc(sizeof (l2arc_read_callback_t), KM_SLEEP); cb->l2rcb_hdr = hdr; cb->l2rcb_bp = *bp; cb->l2rcb_zb = *zb; cb->l2rcb_flags = zio_flags; /* * When Compressed ARC is disabled, but the * L2ARC block is compressed, arc_hdr_size() * will have returned LSIZE rather than PSIZE. */ if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr) && HDR_GET_PSIZE(hdr) != 0) { size = HDR_GET_PSIZE(hdr); } asize = vdev_psize_to_asize(vd, size); if (asize != size) { abd = abd_alloc_for_io(asize, HDR_ISTYPE_METADATA(hdr)); cb->l2rcb_abd = abd; } else { abd = hdr_abd; } ASSERT(addr >= VDEV_LABEL_START_SIZE && addr + asize <= vd->vdev_psize - VDEV_LABEL_END_SIZE); /* * l2arc read. The SCL_L2ARC lock will be * released by l2arc_read_done(). * Issue a null zio if the underlying buffer * was squashed to zero size by compression. */ ASSERT3U(arc_hdr_get_compress(hdr), !=, ZIO_COMPRESS_EMPTY); rzio = zio_read_phys(pio, vd, addr, asize, abd, ZIO_CHECKSUM_OFF, l2arc_read_done, cb, priority, zio_flags | ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY, B_FALSE); acb->acb_zio_head = rzio; if (hash_lock != NULL) mutex_exit(hash_lock); DTRACE_PROBE2(l2arc__read, vdev_t *, vd, zio_t *, rzio); ARCSTAT_INCR(arcstat_l2_read_bytes, HDR_GET_PSIZE(hdr)); if (*arc_flags & ARC_FLAG_NOWAIT) { zio_nowait(rzio); goto out; } ASSERT(*arc_flags & ARC_FLAG_WAIT); if (zio_wait(rzio) == 0) goto out; /* l2arc read error; goto zio_read() */ if (hash_lock != NULL) mutex_enter(hash_lock); } else { DTRACE_PROBE1(l2arc__miss, arc_buf_hdr_t *, hdr); ARCSTAT_BUMP(arcstat_l2_misses); if (HDR_L2_WRITING(hdr)) ARCSTAT_BUMP(arcstat_l2_rw_clash); spa_config_exit(spa, SCL_L2ARC, vd); } } else { if (vd != NULL) spa_config_exit(spa, SCL_L2ARC, vd); /* * Only a spa with l2 should contribute to l2 * miss stats. (Including the case of having a * faulted cache device - that's also a miss.) */ if (spa_has_l2) { /* * Skip ARC stat bump for block pointers with * embedded data. The data are read from the * blkptr itself via * decode_embedded_bp_compressed(). */ if (!embedded_bp) { DTRACE_PROBE1(l2arc__miss, arc_buf_hdr_t *, hdr); ARCSTAT_BUMP(arcstat_l2_misses); } } } rzio = zio_read(pio, spa, bp, hdr_abd, size, arc_read_done, hdr, priority, zio_flags, zb); acb->acb_zio_head = rzio; if (hash_lock != NULL) mutex_exit(hash_lock); if (*arc_flags & ARC_FLAG_WAIT) { rc = zio_wait(rzio); goto out; } ASSERT(*arc_flags & ARC_FLAG_NOWAIT); zio_nowait(rzio); } out: /* embedded bps don't actually go to disk */ if (!embedded_bp) spa_read_history_add(spa, zb, *arc_flags); spl_fstrans_unmark(cookie); return (rc); } arc_prune_t * arc_add_prune_callback(arc_prune_func_t *func, void *private) { arc_prune_t *p; p = kmem_alloc(sizeof (*p), KM_SLEEP); p->p_pfunc = func; p->p_private = private; list_link_init(&p->p_node); zfs_refcount_create(&p->p_refcnt); mutex_enter(&arc_prune_mtx); zfs_refcount_add(&p->p_refcnt, &arc_prune_list); list_insert_head(&arc_prune_list, p); mutex_exit(&arc_prune_mtx); return (p); } void arc_remove_prune_callback(arc_prune_t *p) { boolean_t wait = B_FALSE; mutex_enter(&arc_prune_mtx); list_remove(&arc_prune_list, p); if (zfs_refcount_remove(&p->p_refcnt, &arc_prune_list) > 0) wait = B_TRUE; mutex_exit(&arc_prune_mtx); /* wait for arc_prune_task to finish */ if (wait) taskq_wait_outstanding(arc_prune_taskq, 0); ASSERT0(zfs_refcount_count(&p->p_refcnt)); zfs_refcount_destroy(&p->p_refcnt); kmem_free(p, sizeof (*p)); } /* * Notify the arc that a block was freed, and thus will never be used again. */ void arc_freed(spa_t *spa, const blkptr_t *bp) { arc_buf_hdr_t *hdr; kmutex_t *hash_lock; uint64_t guid = spa_load_guid(spa); ASSERT(!BP_IS_EMBEDDED(bp)); hdr = buf_hash_find(guid, bp, &hash_lock); if (hdr == NULL) return; /* * We might be trying to free a block that is still doing I/O * (i.e. prefetch) or has a reference (i.e. a dedup-ed, * dmu_sync-ed block). If this block is being prefetched, then it * would still have the ARC_FLAG_IO_IN_PROGRESS flag set on the hdr * until the I/O completes. A block may also have a reference if it is * part of a dedup-ed, dmu_synced write. The dmu_sync() function would * have written the new block to its final resting place on disk but * without the dedup flag set. This would have left the hdr in the MRU * state and discoverable. When the txg finally syncs it detects that * the block was overridden in open context and issues an override I/O. * Since this is a dedup block, the override I/O will determine if the * block is already in the DDT. If so, then it will replace the io_bp * with the bp from the DDT and allow the I/O to finish. When the I/O * reaches the done callback, dbuf_write_override_done, it will * check to see if the io_bp and io_bp_override are identical. * If they are not, then it indicates that the bp was replaced with * the bp in the DDT and the override bp is freed. This allows * us to arrive here with a reference on a block that is being * freed. So if we have an I/O in progress, or a reference to * this hdr, then we don't destroy the hdr. */ if (!HDR_HAS_L1HDR(hdr) || (!HDR_IO_IN_PROGRESS(hdr) && zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt))) { arc_change_state(arc_anon, hdr, hash_lock); arc_hdr_destroy(hdr); mutex_exit(hash_lock); } else { mutex_exit(hash_lock); } } /* * Release this buffer from the cache, making it an anonymous buffer. This * must be done after a read and prior to modifying the buffer contents. * If the buffer has more than one reference, we must make * a new hdr for the buffer. */ void arc_release(arc_buf_t *buf, const void *tag) { arc_buf_hdr_t *hdr = buf->b_hdr; /* * It would be nice to assert that if its DMU metadata (level > * 0 || it's the dnode file), then it must be syncing context. * But we don't know that information at this level. */ mutex_enter(&buf->b_evict_lock); ASSERT(HDR_HAS_L1HDR(hdr)); /* * We don't grab the hash lock prior to this check, because if * the buffer's header is in the arc_anon state, it won't be * linked into the hash table. */ if (hdr->b_l1hdr.b_state == arc_anon) { mutex_exit(&buf->b_evict_lock); ASSERT(!HDR_IO_IN_PROGRESS(hdr)); ASSERT(!HDR_IN_HASH_TABLE(hdr)); ASSERT(!HDR_HAS_L2HDR(hdr)); ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1); ASSERT3S(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt), ==, 1); ASSERT(!list_link_active(&hdr->b_l1hdr.b_arc_node)); hdr->b_l1hdr.b_arc_access = 0; /* * If the buf is being overridden then it may already * have a hdr that is not empty. */ buf_discard_identity(hdr); arc_buf_thaw(buf); return; } kmutex_t *hash_lock = HDR_LOCK(hdr); mutex_enter(hash_lock); /* * This assignment is only valid as long as the hash_lock is * held, we must be careful not to reference state or the * b_state field after dropping the lock. */ arc_state_t *state = hdr->b_l1hdr.b_state; ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); ASSERT3P(state, !=, arc_anon); /* this buffer is not on any list */ ASSERT3S(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt), >, 0); if (HDR_HAS_L2HDR(hdr)) { mutex_enter(&hdr->b_l2hdr.b_dev->l2ad_mtx); /* * We have to recheck this conditional again now that * we're holding the l2ad_mtx to prevent a race with * another thread which might be concurrently calling * l2arc_evict(). In that case, l2arc_evict() might have * destroyed the header's L2 portion as we were waiting * to acquire the l2ad_mtx. */ if (HDR_HAS_L2HDR(hdr)) arc_hdr_l2hdr_destroy(hdr); mutex_exit(&hdr->b_l2hdr.b_dev->l2ad_mtx); } /* * Do we have more than one buf? */ if (hdr->b_l1hdr.b_bufcnt > 1) { arc_buf_hdr_t *nhdr; uint64_t spa = hdr->b_spa; uint64_t psize = HDR_GET_PSIZE(hdr); uint64_t lsize = HDR_GET_LSIZE(hdr); boolean_t protected = HDR_PROTECTED(hdr); enum zio_compress compress = arc_hdr_get_compress(hdr); arc_buf_contents_t type = arc_buf_type(hdr); VERIFY3U(hdr->b_type, ==, type); ASSERT(hdr->b_l1hdr.b_buf != buf || buf->b_next != NULL); (void) remove_reference(hdr, hash_lock, tag); if (arc_buf_is_shared(buf) && !ARC_BUF_COMPRESSED(buf)) { ASSERT3P(hdr->b_l1hdr.b_buf, !=, buf); ASSERT(ARC_BUF_LAST(buf)); } /* * Pull the data off of this hdr and attach it to * a new anonymous hdr. Also find the last buffer * in the hdr's buffer list. */ arc_buf_t *lastbuf = arc_buf_remove(hdr, buf); ASSERT3P(lastbuf, !=, NULL); /* * If the current arc_buf_t and the hdr are sharing their data * buffer, then we must stop sharing that block. */ if (arc_buf_is_shared(buf)) { ASSERT3P(hdr->b_l1hdr.b_buf, !=, buf); VERIFY(!arc_buf_is_shared(lastbuf)); /* * First, sever the block sharing relationship between * buf and the arc_buf_hdr_t. */ arc_unshare_buf(hdr, buf); /* * Now we need to recreate the hdr's b_pabd. Since we * have lastbuf handy, we try to share with it, but if * we can't then we allocate a new b_pabd and copy the * data from buf into it. */ if (arc_can_share(hdr, lastbuf)) { arc_share_buf(hdr, lastbuf); } else { arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT); abd_copy_from_buf(hdr->b_l1hdr.b_pabd, buf->b_data, psize); } VERIFY3P(lastbuf->b_data, !=, NULL); } else if (HDR_SHARED_DATA(hdr)) { /* * Uncompressed shared buffers are always at the end * of the list. Compressed buffers don't have the * same requirements. This makes it hard to * simply assert that the lastbuf is shared so * we rely on the hdr's compression flags to determine * if we have a compressed, shared buffer. */ ASSERT(arc_buf_is_shared(lastbuf) || arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF); ASSERT(!ARC_BUF_SHARED(buf)); } ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); ASSERT3P(state, !=, arc_l2c_only); (void) zfs_refcount_remove_many(&state->arcs_size, arc_buf_size(buf), buf); if (zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)) { ASSERT3P(state, !=, arc_l2c_only); (void) zfs_refcount_remove_many( &state->arcs_esize[type], arc_buf_size(buf), buf); } hdr->b_l1hdr.b_bufcnt -= 1; if (ARC_BUF_ENCRYPTED(buf)) hdr->b_crypt_hdr.b_ebufcnt -= 1; arc_cksum_verify(buf); arc_buf_unwatch(buf); /* if this is the last uncompressed buf free the checksum */ if (!arc_hdr_has_uncompressed_buf(hdr)) arc_cksum_free(hdr); mutex_exit(hash_lock); /* * Allocate a new hdr. The new hdr will contain a b_pabd * buffer which will be freed in arc_write(). */ nhdr = arc_hdr_alloc(spa, psize, lsize, protected, compress, hdr->b_complevel, type); ASSERT3P(nhdr->b_l1hdr.b_buf, ==, NULL); ASSERT0(nhdr->b_l1hdr.b_bufcnt); ASSERT0(zfs_refcount_count(&nhdr->b_l1hdr.b_refcnt)); VERIFY3U(nhdr->b_type, ==, type); ASSERT(!HDR_SHARED_DATA(nhdr)); nhdr->b_l1hdr.b_buf = buf; nhdr->b_l1hdr.b_bufcnt = 1; if (ARC_BUF_ENCRYPTED(buf)) nhdr->b_crypt_hdr.b_ebufcnt = 1; (void) zfs_refcount_add(&nhdr->b_l1hdr.b_refcnt, tag); buf->b_hdr = nhdr; mutex_exit(&buf->b_evict_lock); (void) zfs_refcount_add_many(&arc_anon->arcs_size, arc_buf_size(buf), buf); } else { mutex_exit(&buf->b_evict_lock); ASSERT(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 1); /* protected by hash lock, or hdr is on arc_anon */ ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); ASSERT(!HDR_IO_IN_PROGRESS(hdr)); hdr->b_l1hdr.b_mru_hits = 0; hdr->b_l1hdr.b_mru_ghost_hits = 0; hdr->b_l1hdr.b_mfu_hits = 0; hdr->b_l1hdr.b_mfu_ghost_hits = 0; arc_change_state(arc_anon, hdr, hash_lock); hdr->b_l1hdr.b_arc_access = 0; mutex_exit(hash_lock); buf_discard_identity(hdr); arc_buf_thaw(buf); } } int arc_released(arc_buf_t *buf) { int released; mutex_enter(&buf->b_evict_lock); released = (buf->b_data != NULL && buf->b_hdr->b_l1hdr.b_state == arc_anon); mutex_exit(&buf->b_evict_lock); return (released); } #ifdef ZFS_DEBUG int arc_referenced(arc_buf_t *buf) { int referenced; mutex_enter(&buf->b_evict_lock); referenced = (zfs_refcount_count(&buf->b_hdr->b_l1hdr.b_refcnt)); mutex_exit(&buf->b_evict_lock); return (referenced); } #endif static void arc_write_ready(zio_t *zio) { arc_write_callback_t *callback = zio->io_private; arc_buf_t *buf = callback->awcb_buf; arc_buf_hdr_t *hdr = buf->b_hdr; blkptr_t *bp = zio->io_bp; uint64_t psize = BP_IS_HOLE(bp) ? 0 : BP_GET_PSIZE(bp); fstrans_cookie_t cookie = spl_fstrans_mark(); ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT(!zfs_refcount_is_zero(&buf->b_hdr->b_l1hdr.b_refcnt)); ASSERT(hdr->b_l1hdr.b_bufcnt > 0); /* * If we're reexecuting this zio because the pool suspended, then * cleanup any state that was previously set the first time the * callback was invoked. */ if (zio->io_flags & ZIO_FLAG_REEXECUTED) { arc_cksum_free(hdr); arc_buf_unwatch(buf); if (hdr->b_l1hdr.b_pabd != NULL) { if (arc_buf_is_shared(buf)) { arc_unshare_buf(hdr, buf); } else { arc_hdr_free_abd(hdr, B_FALSE); } } if (HDR_HAS_RABD(hdr)) arc_hdr_free_abd(hdr, B_TRUE); } ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); ASSERT(!HDR_HAS_RABD(hdr)); ASSERT(!HDR_SHARED_DATA(hdr)); ASSERT(!arc_buf_is_shared(buf)); callback->awcb_ready(zio, buf, callback->awcb_private); if (HDR_IO_IN_PROGRESS(hdr)) ASSERT(zio->io_flags & ZIO_FLAG_REEXECUTED); arc_hdr_set_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); if (BP_IS_PROTECTED(bp) != !!HDR_PROTECTED(hdr)) hdr = arc_hdr_realloc_crypt(hdr, BP_IS_PROTECTED(bp)); if (BP_IS_PROTECTED(bp)) { /* ZIL blocks are written through zio_rewrite */ ASSERT3U(BP_GET_TYPE(bp), !=, DMU_OT_INTENT_LOG); ASSERT(HDR_PROTECTED(hdr)); if (BP_SHOULD_BYTESWAP(bp)) { if (BP_GET_LEVEL(bp) > 0) { hdr->b_l1hdr.b_byteswap = DMU_BSWAP_UINT64; } else { hdr->b_l1hdr.b_byteswap = DMU_OT_BYTESWAP(BP_GET_TYPE(bp)); } } else { hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; } hdr->b_crypt_hdr.b_ot = BP_GET_TYPE(bp); hdr->b_crypt_hdr.b_dsobj = zio->io_bookmark.zb_objset; zio_crypt_decode_params_bp(bp, hdr->b_crypt_hdr.b_salt, hdr->b_crypt_hdr.b_iv); zio_crypt_decode_mac_bp(bp, hdr->b_crypt_hdr.b_mac); } /* * If this block was written for raw encryption but the zio layer * ended up only authenticating it, adjust the buffer flags now. */ if (BP_IS_AUTHENTICATED(bp) && ARC_BUF_ENCRYPTED(buf)) { arc_hdr_set_flags(hdr, ARC_FLAG_NOAUTH); buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED; if (BP_GET_COMPRESS(bp) == ZIO_COMPRESS_OFF) buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; } else if (BP_IS_HOLE(bp) && ARC_BUF_ENCRYPTED(buf)) { buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED; buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; } /* this must be done after the buffer flags are adjusted */ arc_cksum_compute(buf); enum zio_compress compress; if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) { compress = ZIO_COMPRESS_OFF; } else { ASSERT3U(HDR_GET_LSIZE(hdr), ==, BP_GET_LSIZE(bp)); compress = BP_GET_COMPRESS(bp); } HDR_SET_PSIZE(hdr, psize); arc_hdr_set_compress(hdr, compress); hdr->b_complevel = zio->io_prop.zp_complevel; if (zio->io_error != 0 || psize == 0) goto out; /* * Fill the hdr with data. If the buffer is encrypted we have no choice * but to copy the data into b_radb. If the hdr is compressed, the data * we want is available from the zio, otherwise we can take it from * the buf. * * We might be able to share the buf's data with the hdr here. However, * doing so would cause the ARC to be full of linear ABDs if we write a * lot of shareable data. As a compromise, we check whether scattered * ABDs are allowed, and assume that if they are then the user wants * the ARC to be primarily filled with them regardless of the data being * written. Therefore, if they're allowed then we allocate one and copy * the data into it; otherwise, we share the data directly if we can. */ if (ARC_BUF_ENCRYPTED(buf)) { ASSERT3U(psize, >, 0); ASSERT(ARC_BUF_COMPRESSED(buf)); arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT | ARC_HDR_ALLOC_RDATA | ARC_HDR_USE_RESERVE); abd_copy(hdr->b_crypt_hdr.b_rabd, zio->io_abd, psize); } else if (!abd_size_alloc_linear(arc_buf_size(buf)) || !arc_can_share(hdr, buf)) { /* * Ideally, we would always copy the io_abd into b_pabd, but the * user may have disabled compressed ARC, thus we must check the * hdr's compression setting rather than the io_bp's. */ if (BP_IS_ENCRYPTED(bp)) { ASSERT3U(psize, >, 0); arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT | ARC_HDR_ALLOC_RDATA | ARC_HDR_USE_RESERVE); abd_copy(hdr->b_crypt_hdr.b_rabd, zio->io_abd, psize); } else if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF && !ARC_BUF_COMPRESSED(buf)) { ASSERT3U(psize, >, 0); arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT | ARC_HDR_USE_RESERVE); abd_copy(hdr->b_l1hdr.b_pabd, zio->io_abd, psize); } else { ASSERT3U(zio->io_orig_size, ==, arc_hdr_size(hdr)); arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT | ARC_HDR_USE_RESERVE); abd_copy_from_buf(hdr->b_l1hdr.b_pabd, buf->b_data, arc_buf_size(buf)); } } else { ASSERT3P(buf->b_data, ==, abd_to_buf(zio->io_orig_abd)); ASSERT3U(zio->io_orig_size, ==, arc_buf_size(buf)); ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1); arc_share_buf(hdr, buf); } out: arc_hdr_verify(hdr, bp); spl_fstrans_unmark(cookie); } static void arc_write_children_ready(zio_t *zio) { arc_write_callback_t *callback = zio->io_private; arc_buf_t *buf = callback->awcb_buf; callback->awcb_children_ready(zio, buf, callback->awcb_private); } /* * The SPA calls this callback for each physical write that happens on behalf * of a logical write. See the comment in dbuf_write_physdone() for details. */ static void arc_write_physdone(zio_t *zio) { arc_write_callback_t *cb = zio->io_private; if (cb->awcb_physdone != NULL) cb->awcb_physdone(zio, cb->awcb_buf, cb->awcb_private); } static void arc_write_done(zio_t *zio) { arc_write_callback_t *callback = zio->io_private; arc_buf_t *buf = callback->awcb_buf; arc_buf_hdr_t *hdr = buf->b_hdr; ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); if (zio->io_error == 0) { arc_hdr_verify(hdr, zio->io_bp); if (BP_IS_HOLE(zio->io_bp) || BP_IS_EMBEDDED(zio->io_bp)) { buf_discard_identity(hdr); } else { hdr->b_dva = *BP_IDENTITY(zio->io_bp); hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); } } else { ASSERT(HDR_EMPTY(hdr)); } /* * If the block to be written was all-zero or compressed enough to be * embedded in the BP, no write was performed so there will be no * dva/birth/checksum. The buffer must therefore remain anonymous * (and uncached). */ if (!HDR_EMPTY(hdr)) { arc_buf_hdr_t *exists; kmutex_t *hash_lock; ASSERT3U(zio->io_error, ==, 0); arc_cksum_verify(buf); exists = buf_hash_insert(hdr, &hash_lock); if (exists != NULL) { /* * This can only happen if we overwrite for * sync-to-convergence, because we remove * buffers from the hash table when we arc_free(). */ if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) panic("bad overwrite, hdr=%p exists=%p", (void *)hdr, (void *)exists); ASSERT(zfs_refcount_is_zero( &exists->b_l1hdr.b_refcnt)); arc_change_state(arc_anon, exists, hash_lock); arc_hdr_destroy(exists); mutex_exit(hash_lock); exists = buf_hash_insert(hdr, &hash_lock); ASSERT3P(exists, ==, NULL); } else if (zio->io_flags & ZIO_FLAG_NOPWRITE) { /* nopwrite */ ASSERT(zio->io_prop.zp_nopwrite); if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) panic("bad nopwrite, hdr=%p exists=%p", (void *)hdr, (void *)exists); } else { /* Dedup */ ASSERT(hdr->b_l1hdr.b_bufcnt == 1); ASSERT(hdr->b_l1hdr.b_state == arc_anon); ASSERT(BP_GET_DEDUP(zio->io_bp)); ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); } } arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); /* if it's not anon, we are doing a scrub */ if (exists == NULL && hdr->b_l1hdr.b_state == arc_anon) arc_access(hdr, hash_lock); mutex_exit(hash_lock); } else { arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); } ASSERT(!zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); callback->awcb_done(zio, buf, callback->awcb_private); abd_free(zio->io_abd); kmem_free(callback, sizeof (arc_write_callback_t)); } zio_t * arc_write(zio_t *pio, spa_t *spa, uint64_t txg, blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, const zio_prop_t *zp, arc_write_done_func_t *ready, arc_write_done_func_t *children_ready, arc_write_done_func_t *physdone, arc_write_done_func_t *done, void *private, zio_priority_t priority, int zio_flags, const zbookmark_phys_t *zb) { arc_buf_hdr_t *hdr = buf->b_hdr; arc_write_callback_t *callback; zio_t *zio; zio_prop_t localprop = *zp; ASSERT3P(ready, !=, NULL); ASSERT3P(done, !=, NULL); ASSERT(!HDR_IO_ERROR(hdr)); ASSERT(!HDR_IO_IN_PROGRESS(hdr)); ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); ASSERT3U(hdr->b_l1hdr.b_bufcnt, >, 0); if (l2arc) arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE); if (ARC_BUF_ENCRYPTED(buf)) { ASSERT(ARC_BUF_COMPRESSED(buf)); localprop.zp_encrypt = B_TRUE; localprop.zp_compress = HDR_GET_COMPRESS(hdr); localprop.zp_complevel = hdr->b_complevel; localprop.zp_byteorder = (hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS) ? ZFS_HOST_BYTEORDER : !ZFS_HOST_BYTEORDER; memcpy(localprop.zp_salt, hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN); memcpy(localprop.zp_iv, hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN); memcpy(localprop.zp_mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN); if (DMU_OT_IS_ENCRYPTED(localprop.zp_type)) { localprop.zp_nopwrite = B_FALSE; localprop.zp_copies = MIN(localprop.zp_copies, SPA_DVAS_PER_BP - 1); } zio_flags |= ZIO_FLAG_RAW; } else if (ARC_BUF_COMPRESSED(buf)) { ASSERT3U(HDR_GET_LSIZE(hdr), !=, arc_buf_size(buf)); localprop.zp_compress = HDR_GET_COMPRESS(hdr); localprop.zp_complevel = hdr->b_complevel; zio_flags |= ZIO_FLAG_RAW_COMPRESS; } callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP); callback->awcb_ready = ready; callback->awcb_children_ready = children_ready; callback->awcb_physdone = physdone; callback->awcb_done = done; callback->awcb_private = private; callback->awcb_buf = buf; /* * The hdr's b_pabd is now stale, free it now. A new data block * will be allocated when the zio pipeline calls arc_write_ready(). */ if (hdr->b_l1hdr.b_pabd != NULL) { /* * If the buf is currently sharing the data block with * the hdr then we need to break that relationship here. * The hdr will remain with a NULL data pointer and the * buf will take sole ownership of the block. */ if (arc_buf_is_shared(buf)) { arc_unshare_buf(hdr, buf); } else { arc_hdr_free_abd(hdr, B_FALSE); } VERIFY3P(buf->b_data, !=, NULL); } if (HDR_HAS_RABD(hdr)) arc_hdr_free_abd(hdr, B_TRUE); if (!(zio_flags & ZIO_FLAG_RAW)) arc_hdr_set_compress(hdr, ZIO_COMPRESS_OFF); ASSERT(!arc_buf_is_shared(buf)); ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); zio = zio_write(pio, spa, txg, bp, abd_get_from_buf(buf->b_data, HDR_GET_LSIZE(hdr)), HDR_GET_LSIZE(hdr), arc_buf_size(buf), &localprop, arc_write_ready, (children_ready != NULL) ? arc_write_children_ready : NULL, arc_write_physdone, arc_write_done, callback, priority, zio_flags, zb); return (zio); } void arc_tempreserve_clear(uint64_t reserve) { atomic_add_64(&arc_tempreserve, -reserve); ASSERT((int64_t)arc_tempreserve >= 0); } int arc_tempreserve_space(spa_t *spa, uint64_t reserve, uint64_t txg) { int error; uint64_t anon_size; if (!arc_no_grow && reserve > arc_c/4 && reserve * 4 > (2ULL << SPA_MAXBLOCKSHIFT)) arc_c = MIN(arc_c_max, reserve * 4); /* * Throttle when the calculated memory footprint for the TXG * exceeds the target ARC size. */ if (reserve > arc_c) { DMU_TX_STAT_BUMP(dmu_tx_memory_reserve); return (SET_ERROR(ERESTART)); } /* * Don't count loaned bufs as in flight dirty data to prevent long * network delays from blocking transactions that are ready to be * assigned to a txg. */ /* assert that it has not wrapped around */ ASSERT3S(atomic_add_64_nv(&arc_loaned_bytes, 0), >=, 0); anon_size = MAX((int64_t)(zfs_refcount_count(&arc_anon->arcs_size) - arc_loaned_bytes), 0); /* * Writes will, almost always, require additional memory allocations * in order to compress/encrypt/etc the data. We therefore need to * make sure that there is sufficient available memory for this. */ error = arc_memory_throttle(spa, reserve, txg); if (error != 0) return (error); /* * Throttle writes when the amount of dirty data in the cache * gets too large. We try to keep the cache less than half full * of dirty blocks so that our sync times don't grow too large. * * In the case of one pool being built on another pool, we want * to make sure we don't end up throttling the lower (backing) * pool when the upper pool is the majority contributor to dirty * data. To insure we make forward progress during throttling, we * also check the current pool's net dirty data and only throttle * if it exceeds zfs_arc_pool_dirty_percent of the anonymous dirty * data in the cache. * * Note: if two requests come in concurrently, we might let them * both succeed, when one of them should fail. Not a huge deal. */ uint64_t total_dirty = reserve + arc_tempreserve + anon_size; uint64_t spa_dirty_anon = spa_dirty_data(spa); uint64_t rarc_c = arc_warm ? arc_c : arc_c_max; if (total_dirty > rarc_c * zfs_arc_dirty_limit_percent / 100 && anon_size > rarc_c * zfs_arc_anon_limit_percent / 100 && spa_dirty_anon > anon_size * zfs_arc_pool_dirty_percent / 100) { #ifdef ZFS_DEBUG uint64_t meta_esize = zfs_refcount_count( &arc_anon->arcs_esize[ARC_BUFC_METADATA]); uint64_t data_esize = zfs_refcount_count(&arc_anon->arcs_esize[ARC_BUFC_DATA]); dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " "anon_data=%lluK tempreserve=%lluK rarc_c=%lluK\n", (u_longlong_t)arc_tempreserve >> 10, (u_longlong_t)meta_esize >> 10, (u_longlong_t)data_esize >> 10, (u_longlong_t)reserve >> 10, (u_longlong_t)rarc_c >> 10); #endif DMU_TX_STAT_BUMP(dmu_tx_dirty_throttle); return (SET_ERROR(ERESTART)); } atomic_add_64(&arc_tempreserve, reserve); return (0); } static void arc_kstat_update_state(arc_state_t *state, kstat_named_t *size, kstat_named_t *evict_data, kstat_named_t *evict_metadata) { size->value.ui64 = zfs_refcount_count(&state->arcs_size); evict_data->value.ui64 = zfs_refcount_count(&state->arcs_esize[ARC_BUFC_DATA]); evict_metadata->value.ui64 = zfs_refcount_count(&state->arcs_esize[ARC_BUFC_METADATA]); } static int arc_kstat_update(kstat_t *ksp, int rw) { arc_stats_t *as = ksp->ks_data; if (rw == KSTAT_WRITE) return (SET_ERROR(EACCES)); as->arcstat_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_hits); as->arcstat_misses.value.ui64 = wmsum_value(&arc_sums.arcstat_misses); as->arcstat_demand_data_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_demand_data_hits); as->arcstat_demand_data_misses.value.ui64 = wmsum_value(&arc_sums.arcstat_demand_data_misses); as->arcstat_demand_metadata_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_demand_metadata_hits); as->arcstat_demand_metadata_misses.value.ui64 = wmsum_value(&arc_sums.arcstat_demand_metadata_misses); as->arcstat_prefetch_data_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_prefetch_data_hits); as->arcstat_prefetch_data_misses.value.ui64 = wmsum_value(&arc_sums.arcstat_prefetch_data_misses); as->arcstat_prefetch_metadata_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_prefetch_metadata_hits); as->arcstat_prefetch_metadata_misses.value.ui64 = wmsum_value(&arc_sums.arcstat_prefetch_metadata_misses); as->arcstat_mru_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_mru_hits); as->arcstat_mru_ghost_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_mru_ghost_hits); as->arcstat_mfu_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_mfu_hits); as->arcstat_mfu_ghost_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_mfu_ghost_hits); as->arcstat_deleted.value.ui64 = wmsum_value(&arc_sums.arcstat_deleted); as->arcstat_mutex_miss.value.ui64 = wmsum_value(&arc_sums.arcstat_mutex_miss); as->arcstat_access_skip.value.ui64 = wmsum_value(&arc_sums.arcstat_access_skip); as->arcstat_evict_skip.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_skip); as->arcstat_evict_not_enough.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_not_enough); as->arcstat_evict_l2_cached.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_l2_cached); as->arcstat_evict_l2_eligible.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_l2_eligible); as->arcstat_evict_l2_eligible_mfu.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_l2_eligible_mfu); as->arcstat_evict_l2_eligible_mru.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_l2_eligible_mru); as->arcstat_evict_l2_ineligible.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_l2_ineligible); as->arcstat_evict_l2_skip.value.ui64 = wmsum_value(&arc_sums.arcstat_evict_l2_skip); as->arcstat_hash_collisions.value.ui64 = wmsum_value(&arc_sums.arcstat_hash_collisions); as->arcstat_hash_chains.value.ui64 = wmsum_value(&arc_sums.arcstat_hash_chains); as->arcstat_size.value.ui64 = aggsum_value(&arc_sums.arcstat_size); as->arcstat_compressed_size.value.ui64 = wmsum_value(&arc_sums.arcstat_compressed_size); as->arcstat_uncompressed_size.value.ui64 = wmsum_value(&arc_sums.arcstat_uncompressed_size); as->arcstat_overhead_size.value.ui64 = wmsum_value(&arc_sums.arcstat_overhead_size); as->arcstat_hdr_size.value.ui64 = wmsum_value(&arc_sums.arcstat_hdr_size); as->arcstat_data_size.value.ui64 = wmsum_value(&arc_sums.arcstat_data_size); as->arcstat_metadata_size.value.ui64 = wmsum_value(&arc_sums.arcstat_metadata_size); as->arcstat_dbuf_size.value.ui64 = wmsum_value(&arc_sums.arcstat_dbuf_size); #if defined(COMPAT_FREEBSD11) as->arcstat_other_size.value.ui64 = wmsum_value(&arc_sums.arcstat_bonus_size) + aggsum_value(&arc_sums.arcstat_dnode_size) + wmsum_value(&arc_sums.arcstat_dbuf_size); #endif arc_kstat_update_state(arc_anon, &as->arcstat_anon_size, &as->arcstat_anon_evictable_data, &as->arcstat_anon_evictable_metadata); arc_kstat_update_state(arc_mru, &as->arcstat_mru_size, &as->arcstat_mru_evictable_data, &as->arcstat_mru_evictable_metadata); arc_kstat_update_state(arc_mru_ghost, &as->arcstat_mru_ghost_size, &as->arcstat_mru_ghost_evictable_data, &as->arcstat_mru_ghost_evictable_metadata); arc_kstat_update_state(arc_mfu, &as->arcstat_mfu_size, &as->arcstat_mfu_evictable_data, &as->arcstat_mfu_evictable_metadata); arc_kstat_update_state(arc_mfu_ghost, &as->arcstat_mfu_ghost_size, &as->arcstat_mfu_ghost_evictable_data, &as->arcstat_mfu_ghost_evictable_metadata); as->arcstat_dnode_size.value.ui64 = aggsum_value(&arc_sums.arcstat_dnode_size); as->arcstat_bonus_size.value.ui64 = wmsum_value(&arc_sums.arcstat_bonus_size); as->arcstat_l2_hits.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_hits); as->arcstat_l2_misses.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_misses); as->arcstat_l2_prefetch_asize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_prefetch_asize); as->arcstat_l2_mru_asize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_mru_asize); as->arcstat_l2_mfu_asize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_mfu_asize); as->arcstat_l2_bufc_data_asize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_bufc_data_asize); as->arcstat_l2_bufc_metadata_asize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_bufc_metadata_asize); as->arcstat_l2_feeds.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_feeds); as->arcstat_l2_rw_clash.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rw_clash); as->arcstat_l2_read_bytes.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_read_bytes); as->arcstat_l2_write_bytes.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_write_bytes); as->arcstat_l2_writes_sent.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_writes_sent); as->arcstat_l2_writes_done.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_writes_done); as->arcstat_l2_writes_error.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_writes_error); as->arcstat_l2_writes_lock_retry.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_writes_lock_retry); as->arcstat_l2_evict_lock_retry.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_evict_lock_retry); as->arcstat_l2_evict_reading.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_evict_reading); as->arcstat_l2_evict_l1cached.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_evict_l1cached); as->arcstat_l2_free_on_write.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_free_on_write); as->arcstat_l2_abort_lowmem.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_abort_lowmem); as->arcstat_l2_cksum_bad.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_cksum_bad); as->arcstat_l2_io_error.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_io_error); as->arcstat_l2_lsize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_lsize); as->arcstat_l2_psize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_psize); as->arcstat_l2_hdr_size.value.ui64 = aggsum_value(&arc_sums.arcstat_l2_hdr_size); as->arcstat_l2_log_blk_writes.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_log_blk_writes); as->arcstat_l2_log_blk_asize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_log_blk_asize); as->arcstat_l2_log_blk_count.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_log_blk_count); as->arcstat_l2_rebuild_success.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_success); as->arcstat_l2_rebuild_abort_unsupported.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_abort_unsupported); as->arcstat_l2_rebuild_abort_io_errors.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_abort_io_errors); as->arcstat_l2_rebuild_abort_dh_errors.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_abort_dh_errors); as->arcstat_l2_rebuild_abort_cksum_lb_errors.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_abort_cksum_lb_errors); as->arcstat_l2_rebuild_abort_lowmem.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_abort_lowmem); as->arcstat_l2_rebuild_size.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_size); as->arcstat_l2_rebuild_asize.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_asize); as->arcstat_l2_rebuild_bufs.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_bufs); as->arcstat_l2_rebuild_bufs_precached.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_bufs_precached); as->arcstat_l2_rebuild_log_blks.value.ui64 = wmsum_value(&arc_sums.arcstat_l2_rebuild_log_blks); as->arcstat_memory_throttle_count.value.ui64 = wmsum_value(&arc_sums.arcstat_memory_throttle_count); as->arcstat_memory_direct_count.value.ui64 = wmsum_value(&arc_sums.arcstat_memory_direct_count); as->arcstat_memory_indirect_count.value.ui64 = wmsum_value(&arc_sums.arcstat_memory_indirect_count); as->arcstat_memory_all_bytes.value.ui64 = arc_all_memory(); as->arcstat_memory_free_bytes.value.ui64 = arc_free_memory(); as->arcstat_memory_available_bytes.value.i64 = arc_available_memory(); as->arcstat_prune.value.ui64 = wmsum_value(&arc_sums.arcstat_prune); as->arcstat_meta_used.value.ui64 = aggsum_value(&arc_sums.arcstat_meta_used); as->arcstat_async_upgrade_sync.value.ui64 = wmsum_value(&arc_sums.arcstat_async_upgrade_sync); as->arcstat_demand_hit_predictive_prefetch.value.ui64 = wmsum_value(&arc_sums.arcstat_demand_hit_predictive_prefetch); as->arcstat_demand_hit_prescient_prefetch.value.ui64 = wmsum_value(&arc_sums.arcstat_demand_hit_prescient_prefetch); as->arcstat_raw_size.value.ui64 = wmsum_value(&arc_sums.arcstat_raw_size); as->arcstat_cached_only_in_progress.value.ui64 = wmsum_value(&arc_sums.arcstat_cached_only_in_progress); as->arcstat_abd_chunk_waste_size.value.ui64 = wmsum_value(&arc_sums.arcstat_abd_chunk_waste_size); return (0); } /* * This function *must* return indices evenly distributed between all * sublists of the multilist. This is needed due to how the ARC eviction * code is laid out; arc_evict_state() assumes ARC buffers are evenly * distributed between all sublists and uses this assumption when * deciding which sublist to evict from and how much to evict from it. */ static unsigned int arc_state_multilist_index_func(multilist_t *ml, void *obj) { arc_buf_hdr_t *hdr = obj; /* * We rely on b_dva to generate evenly distributed index * numbers using buf_hash below. So, as an added precaution, * let's make sure we never add empty buffers to the arc lists. */ ASSERT(!HDR_EMPTY(hdr)); /* * The assumption here, is the hash value for a given * arc_buf_hdr_t will remain constant throughout its lifetime * (i.e. its b_spa, b_dva, and b_birth fields don't change). * Thus, we don't need to store the header's sublist index * on insertion, as this index can be recalculated on removal. * * Also, the low order bits of the hash value are thought to be * distributed evenly. Otherwise, in the case that the multilist * has a power of two number of sublists, each sublists' usage * would not be evenly distributed. In this context full 64bit * division would be a waste of time, so limit it to 32 bits. */ return ((unsigned int)buf_hash(hdr->b_spa, &hdr->b_dva, hdr->b_birth) % multilist_get_num_sublists(ml)); } static unsigned int arc_state_l2c_multilist_index_func(multilist_t *ml, void *obj) { panic("Header %p insert into arc_l2c_only %p", obj, ml); } #define WARN_IF_TUNING_IGNORED(tuning, value, do_warn) do { \ if ((do_warn) && (tuning) && ((tuning) != (value))) { \ cmn_err(CE_WARN, \ "ignoring tunable %s (using %llu instead)", \ (#tuning), (u_longlong_t)(value)); \ } \ } while (0) /* * Called during module initialization and periodically thereafter to * apply reasonable changes to the exposed performance tunings. Can also be * called explicitly by param_set_arc_*() functions when ARC tunables are * updated manually. Non-zero zfs_* values which differ from the currently set * values will be applied. */ void arc_tuning_update(boolean_t verbose) { uint64_t allmem = arc_all_memory(); unsigned long limit; /* Valid range: 32M - */ if ((zfs_arc_min) && (zfs_arc_min != arc_c_min) && (zfs_arc_min >= 2ULL << SPA_MAXBLOCKSHIFT) && (zfs_arc_min <= arc_c_max)) { arc_c_min = zfs_arc_min; arc_c = MAX(arc_c, arc_c_min); } WARN_IF_TUNING_IGNORED(zfs_arc_min, arc_c_min, verbose); /* Valid range: 64M - */ if ((zfs_arc_max) && (zfs_arc_max != arc_c_max) && (zfs_arc_max >= MIN_ARC_MAX) && (zfs_arc_max < allmem) && (zfs_arc_max > arc_c_min)) { arc_c_max = zfs_arc_max; arc_c = MIN(arc_c, arc_c_max); arc_p = (arc_c >> 1); if (arc_meta_limit > arc_c_max) arc_meta_limit = arc_c_max; if (arc_dnode_size_limit > arc_meta_limit) arc_dnode_size_limit = arc_meta_limit; } WARN_IF_TUNING_IGNORED(zfs_arc_max, arc_c_max, verbose); /* Valid range: 16M - */ if ((zfs_arc_meta_min) && (zfs_arc_meta_min != arc_meta_min) && (zfs_arc_meta_min >= 1ULL << SPA_MAXBLOCKSHIFT) && (zfs_arc_meta_min <= arc_c_max)) { arc_meta_min = zfs_arc_meta_min; if (arc_meta_limit < arc_meta_min) arc_meta_limit = arc_meta_min; if (arc_dnode_size_limit < arc_meta_min) arc_dnode_size_limit = arc_meta_min; } WARN_IF_TUNING_IGNORED(zfs_arc_meta_min, arc_meta_min, verbose); /* Valid range: - */ limit = zfs_arc_meta_limit ? zfs_arc_meta_limit : MIN(zfs_arc_meta_limit_percent, 100) * arc_c_max / 100; if ((limit != arc_meta_limit) && (limit >= arc_meta_min) && (limit <= arc_c_max)) arc_meta_limit = limit; WARN_IF_TUNING_IGNORED(zfs_arc_meta_limit, arc_meta_limit, verbose); /* Valid range: - */ limit = zfs_arc_dnode_limit ? zfs_arc_dnode_limit : MIN(zfs_arc_dnode_limit_percent, 100) * arc_meta_limit / 100; if ((limit != arc_dnode_size_limit) && (limit >= arc_meta_min) && (limit <= arc_meta_limit)) arc_dnode_size_limit = limit; WARN_IF_TUNING_IGNORED(zfs_arc_dnode_limit, arc_dnode_size_limit, verbose); /* Valid range: 1 - N */ if (zfs_arc_grow_retry) arc_grow_retry = zfs_arc_grow_retry; /* Valid range: 1 - N */ if (zfs_arc_shrink_shift) { arc_shrink_shift = zfs_arc_shrink_shift; arc_no_grow_shift = MIN(arc_no_grow_shift, arc_shrink_shift -1); } /* Valid range: 1 - N */ if (zfs_arc_p_min_shift) arc_p_min_shift = zfs_arc_p_min_shift; /* Valid range: 1 - N ms */ if (zfs_arc_min_prefetch_ms) arc_min_prefetch_ms = zfs_arc_min_prefetch_ms; /* Valid range: 1 - N ms */ if (zfs_arc_min_prescient_prefetch_ms) { arc_min_prescient_prefetch_ms = zfs_arc_min_prescient_prefetch_ms; } /* Valid range: 0 - 100 */ if ((zfs_arc_lotsfree_percent >= 0) && (zfs_arc_lotsfree_percent <= 100)) arc_lotsfree_percent = zfs_arc_lotsfree_percent; WARN_IF_TUNING_IGNORED(zfs_arc_lotsfree_percent, arc_lotsfree_percent, verbose); /* Valid range: 0 - */ if ((zfs_arc_sys_free) && (zfs_arc_sys_free != arc_sys_free)) arc_sys_free = MIN(MAX(zfs_arc_sys_free, 0), allmem); WARN_IF_TUNING_IGNORED(zfs_arc_sys_free, arc_sys_free, verbose); } static void arc_state_multilist_init(multilist_t *ml, multilist_sublist_index_func_t *index_func, int *maxcountp) { multilist_create(ml, sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), index_func); *maxcountp = MAX(*maxcountp, multilist_get_num_sublists(ml)); } static void arc_state_init(void) { int num_sublists = 0; arc_state_multilist_init(&arc_mru->arcs_list[ARC_BUFC_METADATA], arc_state_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_mru->arcs_list[ARC_BUFC_DATA], arc_state_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA], arc_state_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA], arc_state_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_mfu->arcs_list[ARC_BUFC_METADATA], arc_state_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_mfu->arcs_list[ARC_BUFC_DATA], arc_state_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA], arc_state_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA], arc_state_multilist_index_func, &num_sublists); /* * L2 headers should never be on the L2 state list since they don't * have L1 headers allocated. Special index function asserts that. */ arc_state_multilist_init(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA], arc_state_l2c_multilist_index_func, &num_sublists); arc_state_multilist_init(&arc_l2c_only->arcs_list[ARC_BUFC_DATA], arc_state_l2c_multilist_index_func, &num_sublists); /* * Keep track of the number of markers needed to reclaim buffers from * any ARC state. The markers will be pre-allocated so as to minimize * the number of memory allocations performed by the eviction thread. */ arc_state_evict_marker_count = num_sublists; zfs_refcount_create(&arc_anon->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_create(&arc_anon->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_create(&arc_mru->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_create(&arc_mru->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_create(&arc_mru_ghost->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_create(&arc_mru_ghost->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_create(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_create(&arc_mfu->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_create(&arc_mfu_ghost->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_create(&arc_mfu_ghost->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_create(&arc_l2c_only->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_create(&arc_l2c_only->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_create(&arc_anon->arcs_size); zfs_refcount_create(&arc_mru->arcs_size); zfs_refcount_create(&arc_mru_ghost->arcs_size); zfs_refcount_create(&arc_mfu->arcs_size); zfs_refcount_create(&arc_mfu_ghost->arcs_size); zfs_refcount_create(&arc_l2c_only->arcs_size); wmsum_init(&arc_sums.arcstat_hits, 0); wmsum_init(&arc_sums.arcstat_misses, 0); wmsum_init(&arc_sums.arcstat_demand_data_hits, 0); wmsum_init(&arc_sums.arcstat_demand_data_misses, 0); wmsum_init(&arc_sums.arcstat_demand_metadata_hits, 0); wmsum_init(&arc_sums.arcstat_demand_metadata_misses, 0); wmsum_init(&arc_sums.arcstat_prefetch_data_hits, 0); wmsum_init(&arc_sums.arcstat_prefetch_data_misses, 0); wmsum_init(&arc_sums.arcstat_prefetch_metadata_hits, 0); wmsum_init(&arc_sums.arcstat_prefetch_metadata_misses, 0); wmsum_init(&arc_sums.arcstat_mru_hits, 0); wmsum_init(&arc_sums.arcstat_mru_ghost_hits, 0); wmsum_init(&arc_sums.arcstat_mfu_hits, 0); wmsum_init(&arc_sums.arcstat_mfu_ghost_hits, 0); wmsum_init(&arc_sums.arcstat_deleted, 0); wmsum_init(&arc_sums.arcstat_mutex_miss, 0); wmsum_init(&arc_sums.arcstat_access_skip, 0); wmsum_init(&arc_sums.arcstat_evict_skip, 0); wmsum_init(&arc_sums.arcstat_evict_not_enough, 0); wmsum_init(&arc_sums.arcstat_evict_l2_cached, 0); wmsum_init(&arc_sums.arcstat_evict_l2_eligible, 0); wmsum_init(&arc_sums.arcstat_evict_l2_eligible_mfu, 0); wmsum_init(&arc_sums.arcstat_evict_l2_eligible_mru, 0); wmsum_init(&arc_sums.arcstat_evict_l2_ineligible, 0); wmsum_init(&arc_sums.arcstat_evict_l2_skip, 0); wmsum_init(&arc_sums.arcstat_hash_collisions, 0); wmsum_init(&arc_sums.arcstat_hash_chains, 0); aggsum_init(&arc_sums.arcstat_size, 0); wmsum_init(&arc_sums.arcstat_compressed_size, 0); wmsum_init(&arc_sums.arcstat_uncompressed_size, 0); wmsum_init(&arc_sums.arcstat_overhead_size, 0); wmsum_init(&arc_sums.arcstat_hdr_size, 0); wmsum_init(&arc_sums.arcstat_data_size, 0); wmsum_init(&arc_sums.arcstat_metadata_size, 0); wmsum_init(&arc_sums.arcstat_dbuf_size, 0); aggsum_init(&arc_sums.arcstat_dnode_size, 0); wmsum_init(&arc_sums.arcstat_bonus_size, 0); wmsum_init(&arc_sums.arcstat_l2_hits, 0); wmsum_init(&arc_sums.arcstat_l2_misses, 0); wmsum_init(&arc_sums.arcstat_l2_prefetch_asize, 0); wmsum_init(&arc_sums.arcstat_l2_mru_asize, 0); wmsum_init(&arc_sums.arcstat_l2_mfu_asize, 0); wmsum_init(&arc_sums.arcstat_l2_bufc_data_asize, 0); wmsum_init(&arc_sums.arcstat_l2_bufc_metadata_asize, 0); wmsum_init(&arc_sums.arcstat_l2_feeds, 0); wmsum_init(&arc_sums.arcstat_l2_rw_clash, 0); wmsum_init(&arc_sums.arcstat_l2_read_bytes, 0); wmsum_init(&arc_sums.arcstat_l2_write_bytes, 0); wmsum_init(&arc_sums.arcstat_l2_writes_sent, 0); wmsum_init(&arc_sums.arcstat_l2_writes_done, 0); wmsum_init(&arc_sums.arcstat_l2_writes_error, 0); wmsum_init(&arc_sums.arcstat_l2_writes_lock_retry, 0); wmsum_init(&arc_sums.arcstat_l2_evict_lock_retry, 0); wmsum_init(&arc_sums.arcstat_l2_evict_reading, 0); wmsum_init(&arc_sums.arcstat_l2_evict_l1cached, 0); wmsum_init(&arc_sums.arcstat_l2_free_on_write, 0); wmsum_init(&arc_sums.arcstat_l2_abort_lowmem, 0); wmsum_init(&arc_sums.arcstat_l2_cksum_bad, 0); wmsum_init(&arc_sums.arcstat_l2_io_error, 0); wmsum_init(&arc_sums.arcstat_l2_lsize, 0); wmsum_init(&arc_sums.arcstat_l2_psize, 0); aggsum_init(&arc_sums.arcstat_l2_hdr_size, 0); wmsum_init(&arc_sums.arcstat_l2_log_blk_writes, 0); wmsum_init(&arc_sums.arcstat_l2_log_blk_asize, 0); wmsum_init(&arc_sums.arcstat_l2_log_blk_count, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_success, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_abort_unsupported, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_abort_io_errors, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_abort_dh_errors, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_abort_cksum_lb_errors, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_abort_lowmem, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_size, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_asize, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_bufs, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_bufs_precached, 0); wmsum_init(&arc_sums.arcstat_l2_rebuild_log_blks, 0); wmsum_init(&arc_sums.arcstat_memory_throttle_count, 0); wmsum_init(&arc_sums.arcstat_memory_direct_count, 0); wmsum_init(&arc_sums.arcstat_memory_indirect_count, 0); wmsum_init(&arc_sums.arcstat_prune, 0); aggsum_init(&arc_sums.arcstat_meta_used, 0); wmsum_init(&arc_sums.arcstat_async_upgrade_sync, 0); wmsum_init(&arc_sums.arcstat_demand_hit_predictive_prefetch, 0); wmsum_init(&arc_sums.arcstat_demand_hit_prescient_prefetch, 0); wmsum_init(&arc_sums.arcstat_raw_size, 0); wmsum_init(&arc_sums.arcstat_cached_only_in_progress, 0); wmsum_init(&arc_sums.arcstat_abd_chunk_waste_size, 0); arc_anon->arcs_state = ARC_STATE_ANON; arc_mru->arcs_state = ARC_STATE_MRU; arc_mru_ghost->arcs_state = ARC_STATE_MRU_GHOST; arc_mfu->arcs_state = ARC_STATE_MFU; arc_mfu_ghost->arcs_state = ARC_STATE_MFU_GHOST; arc_l2c_only->arcs_state = ARC_STATE_L2C_ONLY; } static void arc_state_fini(void) { zfs_refcount_destroy(&arc_anon->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_destroy(&arc_anon->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_destroy(&arc_mru->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_destroy(&arc_mru->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_destroy(&arc_mru_ghost->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_destroy(&arc_mru_ghost->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_destroy(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_destroy(&arc_mfu->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_destroy(&arc_mfu_ghost->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_destroy(&arc_mfu_ghost->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_destroy(&arc_l2c_only->arcs_esize[ARC_BUFC_METADATA]); zfs_refcount_destroy(&arc_l2c_only->arcs_esize[ARC_BUFC_DATA]); zfs_refcount_destroy(&arc_anon->arcs_size); zfs_refcount_destroy(&arc_mru->arcs_size); zfs_refcount_destroy(&arc_mru_ghost->arcs_size); zfs_refcount_destroy(&arc_mfu->arcs_size); zfs_refcount_destroy(&arc_mfu_ghost->arcs_size); zfs_refcount_destroy(&arc_l2c_only->arcs_size); multilist_destroy(&arc_mru->arcs_list[ARC_BUFC_METADATA]); multilist_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); multilist_destroy(&arc_mfu->arcs_list[ARC_BUFC_METADATA]); multilist_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); multilist_destroy(&arc_mru->arcs_list[ARC_BUFC_DATA]); multilist_destroy(&arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); multilist_destroy(&arc_mfu->arcs_list[ARC_BUFC_DATA]); multilist_destroy(&arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); multilist_destroy(&arc_l2c_only->arcs_list[ARC_BUFC_METADATA]); multilist_destroy(&arc_l2c_only->arcs_list[ARC_BUFC_DATA]); wmsum_fini(&arc_sums.arcstat_hits); wmsum_fini(&arc_sums.arcstat_misses); wmsum_fini(&arc_sums.arcstat_demand_data_hits); wmsum_fini(&arc_sums.arcstat_demand_data_misses); wmsum_fini(&arc_sums.arcstat_demand_metadata_hits); wmsum_fini(&arc_sums.arcstat_demand_metadata_misses); wmsum_fini(&arc_sums.arcstat_prefetch_data_hits); wmsum_fini(&arc_sums.arcstat_prefetch_data_misses); wmsum_fini(&arc_sums.arcstat_prefetch_metadata_hits); wmsum_fini(&arc_sums.arcstat_prefetch_metadata_misses); wmsum_fini(&arc_sums.arcstat_mru_hits); wmsum_fini(&arc_sums.arcstat_mru_ghost_hits); wmsum_fini(&arc_sums.arcstat_mfu_hits); wmsum_fini(&arc_sums.arcstat_mfu_ghost_hits); wmsum_fini(&arc_sums.arcstat_deleted); wmsum_fini(&arc_sums.arcstat_mutex_miss); wmsum_fini(&arc_sums.arcstat_access_skip); wmsum_fini(&arc_sums.arcstat_evict_skip); wmsum_fini(&arc_sums.arcstat_evict_not_enough); wmsum_fini(&arc_sums.arcstat_evict_l2_cached); wmsum_fini(&arc_sums.arcstat_evict_l2_eligible); wmsum_fini(&arc_sums.arcstat_evict_l2_eligible_mfu); wmsum_fini(&arc_sums.arcstat_evict_l2_eligible_mru); wmsum_fini(&arc_sums.arcstat_evict_l2_ineligible); wmsum_fini(&arc_sums.arcstat_evict_l2_skip); wmsum_fini(&arc_sums.arcstat_hash_collisions); wmsum_fini(&arc_sums.arcstat_hash_chains); aggsum_fini(&arc_sums.arcstat_size); wmsum_fini(&arc_sums.arcstat_compressed_size); wmsum_fini(&arc_sums.arcstat_uncompressed_size); wmsum_fini(&arc_sums.arcstat_overhead_size); wmsum_fini(&arc_sums.arcstat_hdr_size); wmsum_fini(&arc_sums.arcstat_data_size); wmsum_fini(&arc_sums.arcstat_metadata_size); wmsum_fini(&arc_sums.arcstat_dbuf_size); aggsum_fini(&arc_sums.arcstat_dnode_size); wmsum_fini(&arc_sums.arcstat_bonus_size); wmsum_fini(&arc_sums.arcstat_l2_hits); wmsum_fini(&arc_sums.arcstat_l2_misses); wmsum_fini(&arc_sums.arcstat_l2_prefetch_asize); wmsum_fini(&arc_sums.arcstat_l2_mru_asize); wmsum_fini(&arc_sums.arcstat_l2_mfu_asize); wmsum_fini(&arc_sums.arcstat_l2_bufc_data_asize); wmsum_fini(&arc_sums.arcstat_l2_bufc_metadata_asize); wmsum_fini(&arc_sums.arcstat_l2_feeds); wmsum_fini(&arc_sums.arcstat_l2_rw_clash); wmsum_fini(&arc_sums.arcstat_l2_read_bytes); wmsum_fini(&arc_sums.arcstat_l2_write_bytes); wmsum_fini(&arc_sums.arcstat_l2_writes_sent); wmsum_fini(&arc_sums.arcstat_l2_writes_done); wmsum_fini(&arc_sums.arcstat_l2_writes_error); wmsum_fini(&arc_sums.arcstat_l2_writes_lock_retry); wmsum_fini(&arc_sums.arcstat_l2_evict_lock_retry); wmsum_fini(&arc_sums.arcstat_l2_evict_reading); wmsum_fini(&arc_sums.arcstat_l2_evict_l1cached); wmsum_fini(&arc_sums.arcstat_l2_free_on_write); wmsum_fini(&arc_sums.arcstat_l2_abort_lowmem); wmsum_fini(&arc_sums.arcstat_l2_cksum_bad); wmsum_fini(&arc_sums.arcstat_l2_io_error); wmsum_fini(&arc_sums.arcstat_l2_lsize); wmsum_fini(&arc_sums.arcstat_l2_psize); aggsum_fini(&arc_sums.arcstat_l2_hdr_size); wmsum_fini(&arc_sums.arcstat_l2_log_blk_writes); wmsum_fini(&arc_sums.arcstat_l2_log_blk_asize); wmsum_fini(&arc_sums.arcstat_l2_log_blk_count); wmsum_fini(&arc_sums.arcstat_l2_rebuild_success); wmsum_fini(&arc_sums.arcstat_l2_rebuild_abort_unsupported); wmsum_fini(&arc_sums.arcstat_l2_rebuild_abort_io_errors); wmsum_fini(&arc_sums.arcstat_l2_rebuild_abort_dh_errors); wmsum_fini(&arc_sums.arcstat_l2_rebuild_abort_cksum_lb_errors); wmsum_fini(&arc_sums.arcstat_l2_rebuild_abort_lowmem); wmsum_fini(&arc_sums.arcstat_l2_rebuild_size); wmsum_fini(&arc_sums.arcstat_l2_rebuild_asize); wmsum_fini(&arc_sums.arcstat_l2_rebuild_bufs); wmsum_fini(&arc_sums.arcstat_l2_rebuild_bufs_precached); wmsum_fini(&arc_sums.arcstat_l2_rebuild_log_blks); wmsum_fini(&arc_sums.arcstat_memory_throttle_count); wmsum_fini(&arc_sums.arcstat_memory_direct_count); wmsum_fini(&arc_sums.arcstat_memory_indirect_count); wmsum_fini(&arc_sums.arcstat_prune); aggsum_fini(&arc_sums.arcstat_meta_used); wmsum_fini(&arc_sums.arcstat_async_upgrade_sync); wmsum_fini(&arc_sums.arcstat_demand_hit_predictive_prefetch); wmsum_fini(&arc_sums.arcstat_demand_hit_prescient_prefetch); wmsum_fini(&arc_sums.arcstat_raw_size); wmsum_fini(&arc_sums.arcstat_cached_only_in_progress); wmsum_fini(&arc_sums.arcstat_abd_chunk_waste_size); } uint64_t arc_target_bytes(void) { return (arc_c); } void arc_set_limits(uint64_t allmem) { /* Set min cache to 1/32 of all memory, or 32MB, whichever is more. */ arc_c_min = MAX(allmem / 32, 2ULL << SPA_MAXBLOCKSHIFT); /* How to set default max varies by platform. */ arc_c_max = arc_default_max(arc_c_min, allmem); } void arc_init(void) { uint64_t percent, allmem = arc_all_memory(); mutex_init(&arc_evict_lock, NULL, MUTEX_DEFAULT, NULL); list_create(&arc_evict_waiters, sizeof (arc_evict_waiter_t), offsetof(arc_evict_waiter_t, aew_node)); arc_min_prefetch_ms = 1000; arc_min_prescient_prefetch_ms = 6000; #if defined(_KERNEL) arc_lowmem_init(); #endif arc_set_limits(allmem); #ifdef _KERNEL /* * If zfs_arc_max is non-zero at init, meaning it was set in the kernel * environment before the module was loaded, don't block setting the * maximum because it is less than arc_c_min, instead, reset arc_c_min * to a lower value. * zfs_arc_min will be handled by arc_tuning_update(). */ if (zfs_arc_max != 0 && zfs_arc_max >= MIN_ARC_MAX && zfs_arc_max < allmem) { arc_c_max = zfs_arc_max; if (arc_c_min >= arc_c_max) { arc_c_min = MAX(zfs_arc_max / 2, 2ULL << SPA_MAXBLOCKSHIFT); } } #else /* * In userland, there's only the memory pressure that we artificially * create (see arc_available_memory()). Don't let arc_c get too * small, because it can cause transactions to be larger than * arc_c, causing arc_tempreserve_space() to fail. */ arc_c_min = MAX(arc_c_max / 2, 2ULL << SPA_MAXBLOCKSHIFT); #endif arc_c = arc_c_min; arc_p = (arc_c >> 1); /* Set min to 1/2 of arc_c_min */ arc_meta_min = 1ULL << SPA_MAXBLOCKSHIFT; /* * Set arc_meta_limit to a percent of arc_c_max with a floor of * arc_meta_min, and a ceiling of arc_c_max. */ percent = MIN(zfs_arc_meta_limit_percent, 100); arc_meta_limit = MAX(arc_meta_min, (percent * arc_c_max) / 100); percent = MIN(zfs_arc_dnode_limit_percent, 100); arc_dnode_size_limit = (percent * arc_meta_limit) / 100; /* Apply user specified tunings */ arc_tuning_update(B_TRUE); /* if kmem_flags are set, lets try to use less memory */ if (kmem_debugging()) arc_c = arc_c / 2; if (arc_c < arc_c_min) arc_c = arc_c_min; arc_register_hotplug(); arc_state_init(); buf_init(); list_create(&arc_prune_list, sizeof (arc_prune_t), offsetof(arc_prune_t, p_node)); mutex_init(&arc_prune_mtx, NULL, MUTEX_DEFAULT, NULL); arc_prune_taskq = taskq_create("arc_prune", zfs_arc_prune_task_threads, defclsyspri, 100, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC); arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); if (arc_ksp != NULL) { arc_ksp->ks_data = &arc_stats; arc_ksp->ks_update = arc_kstat_update; kstat_install(arc_ksp); } arc_state_evict_markers = arc_state_alloc_markers(arc_state_evict_marker_count); arc_evict_zthr = zthr_create("arc_evict", arc_evict_cb_check, arc_evict_cb, NULL, defclsyspri); arc_reap_zthr = zthr_create_timer("arc_reap", arc_reap_cb_check, arc_reap_cb, NULL, SEC2NSEC(1), minclsyspri); arc_warm = B_FALSE; /* * Calculate maximum amount of dirty data per pool. * * If it has been set by a module parameter, take that. * Otherwise, use a percentage of physical memory defined by * zfs_dirty_data_max_percent (default 10%) with a cap at * zfs_dirty_data_max_max (default 4G or 25% of physical memory). */ #ifdef __LP64__ if (zfs_dirty_data_max_max == 0) zfs_dirty_data_max_max = MIN(4ULL * 1024 * 1024 * 1024, allmem * zfs_dirty_data_max_max_percent / 100); #else if (zfs_dirty_data_max_max == 0) zfs_dirty_data_max_max = MIN(1ULL * 1024 * 1024 * 1024, allmem * zfs_dirty_data_max_max_percent / 100); #endif if (zfs_dirty_data_max == 0) { zfs_dirty_data_max = allmem * zfs_dirty_data_max_percent / 100; zfs_dirty_data_max = MIN(zfs_dirty_data_max, zfs_dirty_data_max_max); } if (zfs_wrlog_data_max == 0) { /* * dp_wrlog_total is reduced for each txg at the end of * spa_sync(). However, dp_dirty_total is reduced every time * a block is written out. Thus under normal operation, * dp_wrlog_total could grow 2 times as big as * zfs_dirty_data_max. */ zfs_wrlog_data_max = zfs_dirty_data_max * 2; } } void arc_fini(void) { arc_prune_t *p; #ifdef _KERNEL arc_lowmem_fini(); #endif /* _KERNEL */ /* Use B_TRUE to ensure *all* buffers are evicted */ arc_flush(NULL, B_TRUE); if (arc_ksp != NULL) { kstat_delete(arc_ksp); arc_ksp = NULL; } taskq_wait(arc_prune_taskq); taskq_destroy(arc_prune_taskq); mutex_enter(&arc_prune_mtx); while ((p = list_head(&arc_prune_list)) != NULL) { list_remove(&arc_prune_list, p); zfs_refcount_remove(&p->p_refcnt, &arc_prune_list); zfs_refcount_destroy(&p->p_refcnt); kmem_free(p, sizeof (*p)); } mutex_exit(&arc_prune_mtx); list_destroy(&arc_prune_list); mutex_destroy(&arc_prune_mtx); (void) zthr_cancel(arc_evict_zthr); (void) zthr_cancel(arc_reap_zthr); arc_state_free_markers(arc_state_evict_markers, arc_state_evict_marker_count); mutex_destroy(&arc_evict_lock); list_destroy(&arc_evict_waiters); /* * Free any buffers that were tagged for destruction. This needs * to occur before arc_state_fini() runs and destroys the aggsum * values which are updated when freeing scatter ABDs. */ l2arc_do_free_on_write(); /* * buf_fini() must proceed arc_state_fini() because buf_fin() may * trigger the release of kmem magazines, which can callback to * arc_space_return() which accesses aggsums freed in act_state_fini(). */ buf_fini(); arc_state_fini(); arc_unregister_hotplug(); /* * We destroy the zthrs after all the ARC state has been * torn down to avoid the case of them receiving any * wakeup() signals after they are destroyed. */ zthr_destroy(arc_evict_zthr); zthr_destroy(arc_reap_zthr); ASSERT0(arc_loaned_bytes); } /* * Level 2 ARC * * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. * It uses dedicated storage devices to hold cached data, which are populated * using large infrequent writes. The main role of this cache is to boost * the performance of random read workloads. The intended L2ARC devices * include short-stroked disks, solid state disks, and other media with * substantially faster read latency than disk. * * +-----------------------+ * | ARC | * +-----------------------+ * | ^ ^ * | | | * l2arc_feed_thread() arc_read() * | | | * | l2arc read | * V | | * +---------------+ | * | L2ARC | | * +---------------+ | * | ^ | * l2arc_write() | | * | | | * V | | * +-------+ +-------+ * | vdev | | vdev | * | cache | | cache | * +-------+ +-------+ * +=========+ .-----. * : L2ARC : |-_____-| * : devices : | Disks | * +=========+ `-_____-' * * Read requests are satisfied from the following sources, in order: * * 1) ARC * 2) vdev cache of L2ARC devices * 3) L2ARC devices * 4) vdev cache of disks * 5) disks * * Some L2ARC device types exhibit extremely slow write performance. * To accommodate for this there are some significant differences between * the L2ARC and traditional cache design: * * 1. There is no eviction path from the ARC to the L2ARC. Evictions from * the ARC behave as usual, freeing buffers and placing headers on ghost * lists. The ARC does not send buffers to the L2ARC during eviction as * this would add inflated write latencies for all ARC memory pressure. * * 2. The L2ARC attempts to cache data from the ARC before it is evicted. * It does this by periodically scanning buffers from the eviction-end of * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are * not already there. It scans until a headroom of buffers is satisfied, * which itself is a buffer for ARC eviction. If a compressible buffer is * found during scanning and selected for writing to an L2ARC device, we * temporarily boost scanning headroom during the next scan cycle to make * sure we adapt to compression effects (which might significantly reduce * the data volume we write to L2ARC). The thread that does this is * l2arc_feed_thread(), illustrated below; example sizes are included to * provide a better sense of ratio than this diagram: * * head --> tail * +---------------------+----------+ * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC * +---------------------+----------+ | o L2ARC eligible * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer * +---------------------+----------+ | * 15.9 Gbytes ^ 32 Mbytes | * headroom | * l2arc_feed_thread() * | * l2arc write hand <--[oooo]--' * | 8 Mbyte * | write max * V * +==============================+ * L2ARC dev |####|#|###|###| |####| ... | * +==============================+ * 32 Gbytes * * 3. If an ARC buffer is copied to the L2ARC but then hit instead of * evicted, then the L2ARC has cached a buffer much sooner than it probably * needed to, potentially wasting L2ARC device bandwidth and storage. It is * safe to say that this is an uncommon case, since buffers at the end of * the ARC lists have moved there due to inactivity. * * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, * then the L2ARC simply misses copying some buffers. This serves as a * pressure valve to prevent heavy read workloads from both stalling the ARC * with waits and clogging the L2ARC with writes. This also helps prevent * the potential for the L2ARC to churn if it attempts to cache content too * quickly, such as during backups of the entire pool. * * 5. After system boot and before the ARC has filled main memory, there are * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru * lists can remain mostly static. Instead of searching from tail of these * lists as pictured, the l2arc_feed_thread() will search from the list heads * for eligible buffers, greatly increasing its chance of finding them. * * The L2ARC device write speed is also boosted during this time so that * the L2ARC warms up faster. Since there have been no ARC evictions yet, * there are no L2ARC reads, and no fear of degrading read performance * through increased writes. * * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that * the vdev queue can aggregate them into larger and fewer writes. Each * device is written to in a rotor fashion, sweeping writes through * available space then repeating. * * 7. The L2ARC does not store dirty content. It never needs to flush * write buffers back to disk based storage. * * 8. If an ARC buffer is written (and dirtied) which also exists in the * L2ARC, the now stale L2ARC buffer is immediately dropped. * * The performance of the L2ARC can be tweaked by a number of tunables, which * may be necessary for different workloads: * * l2arc_write_max max write bytes per interval * l2arc_write_boost extra write bytes during device warmup * l2arc_noprefetch skip caching prefetched buffers * l2arc_headroom number of max device writes to precache * l2arc_headroom_boost when we find compressed buffers during ARC * scanning, we multiply headroom by this * percentage factor for the next scan cycle, * since more compressed buffers are likely to * be present * l2arc_feed_secs seconds between L2ARC writing * * Tunables may be removed or added as future performance improvements are * integrated, and also may become zpool properties. * * There are three key functions that control how the L2ARC warms up: * * l2arc_write_eligible() check if a buffer is eligible to cache * l2arc_write_size() calculate how much to write * l2arc_write_interval() calculate sleep delay between writes * * These three functions determine what to write, how much, and how quickly * to send writes. * * L2ARC persistence: * * When writing buffers to L2ARC, we periodically add some metadata to * make sure we can pick them up after reboot, thus dramatically reducing * the impact that any downtime has on the performance of storage systems * with large caches. * * The implementation works fairly simply by integrating the following two * modifications: * * *) When writing to the L2ARC, we occasionally write a "l2arc log block", * which is an additional piece of metadata which describes what's been * written. This allows us to rebuild the arc_buf_hdr_t structures of the * main ARC buffers. There are 2 linked-lists of log blocks headed by * dh_start_lbps[2]. We alternate which chain we append to, so they are * time-wise and offset-wise interleaved, but that is an optimization rather * than for correctness. The log block also includes a pointer to the * previous block in its chain. * * *) We reserve SPA_MINBLOCKSIZE of space at the start of each L2ARC device * for our header bookkeeping purposes. This contains a device header, * which contains our top-level reference structures. We update it each * time we write a new log block, so that we're able to locate it in the * L2ARC device. If this write results in an inconsistent device header * (e.g. due to power failure), we detect this by verifying the header's * checksum and simply fail to reconstruct the L2ARC after reboot. * * Implementation diagram: * * +=== L2ARC device (not to scale) ======================================+ * | ___two newest log block pointers__.__________ | * | / \dh_start_lbps[1] | * | / \ \dh_start_lbps[0]| * |.___/__. V V | * ||L2 dev|....|lb |bufs |lb |bufs |lb |bufs |lb |bufs |lb |---(empty)---| * || hdr| ^ /^ /^ / / | * |+------+ ...--\-------/ \-----/--\------/ / | * | \--------------/ \--------------/ | * +======================================================================+ * * As can be seen on the diagram, rather than using a simple linked list, * we use a pair of linked lists with alternating elements. This is a * performance enhancement due to the fact that we only find out the * address of the next log block access once the current block has been * completely read in. Obviously, this hurts performance, because we'd be * keeping the device's I/O queue at only a 1 operation deep, thus * incurring a large amount of I/O round-trip latency. Having two lists * allows us to fetch two log blocks ahead of where we are currently * rebuilding L2ARC buffers. * * On-device data structures: * * L2ARC device header: l2arc_dev_hdr_phys_t * L2ARC log block: l2arc_log_blk_phys_t * * L2ARC reconstruction: * * When writing data, we simply write in the standard rotary fashion, * evicting buffers as we go and simply writing new data over them (writing * a new log block every now and then). This obviously means that once we * loop around the end of the device, we will start cutting into an already * committed log block (and its referenced data buffers), like so: * * current write head__ __old tail * \ / * V V * <--|bufs |lb |bufs |lb | |bufs |lb |bufs |lb |--> * ^ ^^^^^^^^^___________________________________ * | \ * <> may overwrite this blk and/or its bufs --' * * When importing the pool, we detect this situation and use it to stop * our scanning process (see l2arc_rebuild). * * There is one significant caveat to consider when rebuilding ARC contents * from an L2ARC device: what about invalidated buffers? Given the above * construction, we cannot update blocks which we've already written to amend * them to remove buffers which were invalidated. Thus, during reconstruction, * we might be populating the cache with buffers for data that's not on the * main pool anymore, or may have been overwritten! * * As it turns out, this isn't a problem. Every arc_read request includes * both the DVA and, crucially, the birth TXG of the BP the caller is * looking for. So even if the cache were populated by completely rotten * blocks for data that had been long deleted and/or overwritten, we'll * never actually return bad data from the cache, since the DVA with the * birth TXG uniquely identify a block in space and time - once created, * a block is immutable on disk. The worst thing we have done is wasted * some time and memory at l2arc rebuild to reconstruct outdated ARC * entries that will get dropped from the l2arc as it is being updated * with new blocks. * * L2ARC buffers that have been evicted by l2arc_evict() ahead of the write * hand are not restored. This is done by saving the offset (in bytes) * l2arc_evict() has evicted to in the L2ARC device header and taking it * into account when restoring buffers. */ static boolean_t l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *hdr) { /* * A buffer is *not* eligible for the L2ARC if it: * 1. belongs to a different spa. * 2. is already cached on the L2ARC. * 3. has an I/O in progress (it may be an incomplete read). * 4. is flagged not eligible (zfs property). */ if (hdr->b_spa != spa_guid || HDR_HAS_L2HDR(hdr) || HDR_IO_IN_PROGRESS(hdr) || !HDR_L2CACHE(hdr)) return (B_FALSE); return (B_TRUE); } static uint64_t l2arc_write_size(l2arc_dev_t *dev) { uint64_t size, dev_size, tsize; /* * Make sure our globals have meaningful values in case the user * altered them. */ size = l2arc_write_max; if (size == 0) { cmn_err(CE_NOTE, "Bad value for l2arc_write_max, value must " "be greater than zero, resetting it to the default (%d)", L2ARC_WRITE_SIZE); size = l2arc_write_max = L2ARC_WRITE_SIZE; } if (arc_warm == B_FALSE) size += l2arc_write_boost; /* * Make sure the write size does not exceed the size of the cache * device. This is important in l2arc_evict(), otherwise infinite * iteration can occur. */ dev_size = dev->l2ad_end - dev->l2ad_start; tsize = size + l2arc_log_blk_overhead(size, dev); if (dev->l2ad_vdev->vdev_has_trim && l2arc_trim_ahead > 0) tsize += MAX(64 * 1024 * 1024, (tsize * l2arc_trim_ahead) / 100); if (tsize >= dev_size) { cmn_err(CE_NOTE, "l2arc_write_max or l2arc_write_boost " "plus the overhead of log blocks (persistent L2ARC, " "%llu bytes) exceeds the size of the cache device " "(guid %llu), resetting them to the default (%d)", (u_longlong_t)l2arc_log_blk_overhead(size, dev), (u_longlong_t)dev->l2ad_vdev->vdev_guid, L2ARC_WRITE_SIZE); size = l2arc_write_max = l2arc_write_boost = L2ARC_WRITE_SIZE; if (arc_warm == B_FALSE) size += l2arc_write_boost; } return (size); } static clock_t l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) { clock_t interval, next, now; /* * If the ARC lists are busy, increase our write rate; if the * lists are stale, idle back. This is achieved by checking * how much we previously wrote - if it was more than half of * what we wanted, schedule the next write much sooner. */ if (l2arc_feed_again && wrote > (wanted / 2)) interval = (hz * l2arc_feed_min_ms) / 1000; else interval = hz * l2arc_feed_secs; now = ddi_get_lbolt(); next = MAX(now, MIN(now + interval, began + interval)); return (next); } /* * Cycle through L2ARC devices. This is how L2ARC load balances. * If a device is returned, this also returns holding the spa config lock. */ static l2arc_dev_t * l2arc_dev_get_next(void) { l2arc_dev_t *first, *next = NULL; /* * Lock out the removal of spas (spa_namespace_lock), then removal * of cache devices (l2arc_dev_mtx). Once a device has been selected, * both locks will be dropped and a spa config lock held instead. */ mutex_enter(&spa_namespace_lock); mutex_enter(&l2arc_dev_mtx); /* if there are no vdevs, there is nothing to do */ if (l2arc_ndev == 0) goto out; first = NULL; next = l2arc_dev_last; do { /* loop around the list looking for a non-faulted vdev */ if (next == NULL) { next = list_head(l2arc_dev_list); } else { next = list_next(l2arc_dev_list, next); if (next == NULL) next = list_head(l2arc_dev_list); } /* if we have come back to the start, bail out */ if (first == NULL) first = next; else if (next == first) break; } while (vdev_is_dead(next->l2ad_vdev) || next->l2ad_rebuild || next->l2ad_trim_all); /* if we were unable to find any usable vdevs, return NULL */ if (vdev_is_dead(next->l2ad_vdev) || next->l2ad_rebuild || next->l2ad_trim_all) next = NULL; l2arc_dev_last = next; out: mutex_exit(&l2arc_dev_mtx); /* * Grab the config lock to prevent the 'next' device from being * removed while we are writing to it. */ if (next != NULL) spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); mutex_exit(&spa_namespace_lock); return (next); } /* * Free buffers that were tagged for destruction. */ static void l2arc_do_free_on_write(void) { list_t *buflist; l2arc_data_free_t *df, *df_prev; mutex_enter(&l2arc_free_on_write_mtx); buflist = l2arc_free_on_write; for (df = list_tail(buflist); df; df = df_prev) { df_prev = list_prev(buflist, df); ASSERT3P(df->l2df_abd, !=, NULL); abd_free(df->l2df_abd); list_remove(buflist, df); kmem_free(df, sizeof (l2arc_data_free_t)); } mutex_exit(&l2arc_free_on_write_mtx); } /* * A write to a cache device has completed. Update all headers to allow * reads from these buffers to begin. */ static void l2arc_write_done(zio_t *zio) { l2arc_write_callback_t *cb; l2arc_lb_abd_buf_t *abd_buf; l2arc_lb_ptr_buf_t *lb_ptr_buf; l2arc_dev_t *dev; l2arc_dev_hdr_phys_t *l2dhdr; list_t *buflist; arc_buf_hdr_t *head, *hdr, *hdr_prev; kmutex_t *hash_lock; int64_t bytes_dropped = 0; cb = zio->io_private; ASSERT3P(cb, !=, NULL); dev = cb->l2wcb_dev; l2dhdr = dev->l2ad_dev_hdr; ASSERT3P(dev, !=, NULL); head = cb->l2wcb_head; ASSERT3P(head, !=, NULL); buflist = &dev->l2ad_buflist; ASSERT3P(buflist, !=, NULL); DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, l2arc_write_callback_t *, cb); /* * All writes completed, or an error was hit. */ top: mutex_enter(&dev->l2ad_mtx); for (hdr = list_prev(buflist, head); hdr; hdr = hdr_prev) { hdr_prev = list_prev(buflist, hdr); hash_lock = HDR_LOCK(hdr); /* * We cannot use mutex_enter or else we can deadlock * with l2arc_write_buffers (due to swapping the order * the hash lock and l2ad_mtx are taken). */ if (!mutex_tryenter(hash_lock)) { /* * Missed the hash lock. We must retry so we * don't leave the ARC_FLAG_L2_WRITING bit set. */ ARCSTAT_BUMP(arcstat_l2_writes_lock_retry); /* * We don't want to rescan the headers we've * already marked as having been written out, so * we reinsert the head node so we can pick up * where we left off. */ list_remove(buflist, head); list_insert_after(buflist, hdr, head); mutex_exit(&dev->l2ad_mtx); /* * We wait for the hash lock to become available * to try and prevent busy waiting, and increase * the chance we'll be able to acquire the lock * the next time around. */ mutex_enter(hash_lock); mutex_exit(hash_lock); goto top; } /* * We could not have been moved into the arc_l2c_only * state while in-flight due to our ARC_FLAG_L2_WRITING * bit being set. Let's just ensure that's being enforced. */ ASSERT(HDR_HAS_L1HDR(hdr)); /* * Skipped - drop L2ARC entry and mark the header as no * longer L2 eligibile. */ if (zio->io_error != 0) { /* * Error - drop L2ARC entry. */ list_remove(buflist, hdr); arc_hdr_clear_flags(hdr, ARC_FLAG_HAS_L2HDR); uint64_t psize = HDR_GET_PSIZE(hdr); l2arc_hdr_arcstats_decrement(hdr); bytes_dropped += vdev_psize_to_asize(dev->l2ad_vdev, psize); (void) zfs_refcount_remove_many(&dev->l2ad_alloc, arc_hdr_size(hdr), hdr); } /* * Allow ARC to begin reads and ghost list evictions to * this L2ARC entry. */ arc_hdr_clear_flags(hdr, ARC_FLAG_L2_WRITING); mutex_exit(hash_lock); } /* * Free the allocated abd buffers for writing the log blocks. * If the zio failed reclaim the allocated space and remove the * pointers to these log blocks from the log block pointer list * of the L2ARC device. */ while ((abd_buf = list_remove_tail(&cb->l2wcb_abd_list)) != NULL) { abd_free(abd_buf->abd); zio_buf_free(abd_buf, sizeof (*abd_buf)); if (zio->io_error != 0) { lb_ptr_buf = list_remove_head(&dev->l2ad_lbptr_list); /* * L2BLK_GET_PSIZE returns aligned size for log * blocks. */ uint64_t asize = L2BLK_GET_PSIZE((lb_ptr_buf->lb_ptr)->lbp_prop); bytes_dropped += asize; ARCSTAT_INCR(arcstat_l2_log_blk_asize, -asize); ARCSTAT_BUMPDOWN(arcstat_l2_log_blk_count); zfs_refcount_remove_many(&dev->l2ad_lb_asize, asize, lb_ptr_buf); zfs_refcount_remove(&dev->l2ad_lb_count, lb_ptr_buf); kmem_free(lb_ptr_buf->lb_ptr, sizeof (l2arc_log_blkptr_t)); kmem_free(lb_ptr_buf, sizeof (l2arc_lb_ptr_buf_t)); } } list_destroy(&cb->l2wcb_abd_list); if (zio->io_error != 0) { ARCSTAT_BUMP(arcstat_l2_writes_error); /* * Restore the lbps array in the header to its previous state. * If the list of log block pointers is empty, zero out the * log block pointers in the device header. */ lb_ptr_buf = list_head(&dev->l2ad_lbptr_list); for (int i = 0; i < 2; i++) { if (lb_ptr_buf == NULL) { /* * If the list is empty zero out the device * header. Otherwise zero out the second log * block pointer in the header. */ if (i == 0) { memset(l2dhdr, 0, dev->l2ad_dev_hdr_asize); } else { memset(&l2dhdr->dh_start_lbps[i], 0, sizeof (l2arc_log_blkptr_t)); } break; } memcpy(&l2dhdr->dh_start_lbps[i], lb_ptr_buf->lb_ptr, sizeof (l2arc_log_blkptr_t)); lb_ptr_buf = list_next(&dev->l2ad_lbptr_list, lb_ptr_buf); } } ARCSTAT_BUMP(arcstat_l2_writes_done); list_remove(buflist, head); ASSERT(!HDR_HAS_L1HDR(head)); kmem_cache_free(hdr_l2only_cache, head); mutex_exit(&dev->l2ad_mtx); ASSERT(dev->l2ad_vdev != NULL); vdev_space_update(dev->l2ad_vdev, -bytes_dropped, 0, 0); l2arc_do_free_on_write(); kmem_free(cb, sizeof (l2arc_write_callback_t)); } static int l2arc_untransform(zio_t *zio, l2arc_read_callback_t *cb) { int ret; spa_t *spa = zio->io_spa; arc_buf_hdr_t *hdr = cb->l2rcb_hdr; blkptr_t *bp = zio->io_bp; uint8_t salt[ZIO_DATA_SALT_LEN]; uint8_t iv[ZIO_DATA_IV_LEN]; uint8_t mac[ZIO_DATA_MAC_LEN]; boolean_t no_crypt = B_FALSE; /* * ZIL data is never be written to the L2ARC, so we don't need * special handling for its unique MAC storage. */ ASSERT3U(BP_GET_TYPE(bp), !=, DMU_OT_INTENT_LOG); ASSERT(MUTEX_HELD(HDR_LOCK(hdr))); ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); /* * If the data was encrypted, decrypt it now. Note that * we must check the bp here and not the hdr, since the * hdr does not have its encryption parameters updated * until arc_read_done(). */ if (BP_IS_ENCRYPTED(bp)) { abd_t *eabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, ARC_HDR_DO_ADAPT | ARC_HDR_USE_RESERVE); zio_crypt_decode_params_bp(bp, salt, iv); zio_crypt_decode_mac_bp(bp, mac); ret = spa_do_crypt_abd(B_FALSE, spa, &cb->l2rcb_zb, BP_GET_TYPE(bp), BP_GET_DEDUP(bp), BP_SHOULD_BYTESWAP(bp), salt, iv, mac, HDR_GET_PSIZE(hdr), eabd, hdr->b_l1hdr.b_pabd, &no_crypt); if (ret != 0) { arc_free_data_abd(hdr, eabd, arc_hdr_size(hdr), hdr); goto error; } /* * If we actually performed decryption, replace b_pabd * with the decrypted data. Otherwise we can just throw * our decryption buffer away. */ if (!no_crypt) { arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, arc_hdr_size(hdr), hdr); hdr->b_l1hdr.b_pabd = eabd; zio->io_abd = eabd; } else { arc_free_data_abd(hdr, eabd, arc_hdr_size(hdr), hdr); } } /* * If the L2ARC block was compressed, but ARC compression * is disabled we decompress the data into a new buffer and * replace the existing data. */ if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr)) { abd_t *cabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, ARC_HDR_DO_ADAPT | ARC_HDR_USE_RESERVE); void *tmp = abd_borrow_buf(cabd, arc_hdr_size(hdr)); ret = zio_decompress_data(HDR_GET_COMPRESS(hdr), hdr->b_l1hdr.b_pabd, tmp, HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr), &hdr->b_complevel); if (ret != 0) { abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr)); arc_free_data_abd(hdr, cabd, arc_hdr_size(hdr), hdr); goto error; } abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr)); arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, arc_hdr_size(hdr), hdr); hdr->b_l1hdr.b_pabd = cabd; zio->io_abd = cabd; zio->io_size = HDR_GET_LSIZE(hdr); } return (0); error: return (ret); } /* * A read to a cache device completed. Validate buffer contents before * handing over to the regular ARC routines. */ static void l2arc_read_done(zio_t *zio) { int tfm_error = 0; l2arc_read_callback_t *cb = zio->io_private; arc_buf_hdr_t *hdr; kmutex_t *hash_lock; boolean_t valid_cksum; boolean_t using_rdata = (BP_IS_ENCRYPTED(&cb->l2rcb_bp) && (cb->l2rcb_flags & ZIO_FLAG_RAW_ENCRYPT)); ASSERT3P(zio->io_vd, !=, NULL); ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); ASSERT3P(cb, !=, NULL); hdr = cb->l2rcb_hdr; ASSERT3P(hdr, !=, NULL); hash_lock = HDR_LOCK(hdr); mutex_enter(hash_lock); ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); /* * If the data was read into a temporary buffer, * move it and free the buffer. */ if (cb->l2rcb_abd != NULL) { ASSERT3U(arc_hdr_size(hdr), <, zio->io_size); if (zio->io_error == 0) { if (using_rdata) { abd_copy(hdr->b_crypt_hdr.b_rabd, cb->l2rcb_abd, arc_hdr_size(hdr)); } else { abd_copy(hdr->b_l1hdr.b_pabd, cb->l2rcb_abd, arc_hdr_size(hdr)); } } /* * The following must be done regardless of whether * there was an error: * - free the temporary buffer * - point zio to the real ARC buffer * - set zio size accordingly * These are required because zio is either re-used for * an I/O of the block in the case of the error * or the zio is passed to arc_read_done() and it * needs real data. */ abd_free(cb->l2rcb_abd); zio->io_size = zio->io_orig_size = arc_hdr_size(hdr); if (using_rdata) { ASSERT(HDR_HAS_RABD(hdr)); zio->io_abd = zio->io_orig_abd = hdr->b_crypt_hdr.b_rabd; } else { ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); zio->io_abd = zio->io_orig_abd = hdr->b_l1hdr.b_pabd; } } ASSERT3P(zio->io_abd, !=, NULL); /* * Check this survived the L2ARC journey. */ ASSERT(zio->io_abd == hdr->b_l1hdr.b_pabd || (HDR_HAS_RABD(hdr) && zio->io_abd == hdr->b_crypt_hdr.b_rabd)); zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ zio->io_prop.zp_complevel = hdr->b_complevel; valid_cksum = arc_cksum_is_equal(hdr, zio); /* * b_rabd will always match the data as it exists on disk if it is * being used. Therefore if we are reading into b_rabd we do not * attempt to untransform the data. */ if (valid_cksum && !using_rdata) tfm_error = l2arc_untransform(zio, cb); if (valid_cksum && tfm_error == 0 && zio->io_error == 0 && !HDR_L2_EVICTED(hdr)) { mutex_exit(hash_lock); zio->io_private = hdr; arc_read_done(zio); } else { /* * Buffer didn't survive caching. Increment stats and * reissue to the original storage device. */ if (zio->io_error != 0) { ARCSTAT_BUMP(arcstat_l2_io_error); } else { zio->io_error = SET_ERROR(EIO); } if (!valid_cksum || tfm_error != 0) ARCSTAT_BUMP(arcstat_l2_cksum_bad); /* * If there's no waiter, issue an async i/o to the primary * storage now. If there *is* a waiter, the caller must * issue the i/o in a context where it's OK to block. */ if (zio->io_waiter == NULL) { zio_t *pio = zio_unique_parent(zio); void *abd = (using_rdata) ? hdr->b_crypt_hdr.b_rabd : hdr->b_l1hdr.b_pabd; ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); zio = zio_read(pio, zio->io_spa, zio->io_bp, abd, zio->io_size, arc_read_done, hdr, zio->io_priority, cb->l2rcb_flags, &cb->l2rcb_zb); /* * Original ZIO will be freed, so we need to update * ARC header with the new ZIO pointer to be used * by zio_change_priority() in arc_read(). */ for (struct arc_callback *acb = hdr->b_l1hdr.b_acb; acb != NULL; acb = acb->acb_next) acb->acb_zio_head = zio; mutex_exit(hash_lock); zio_nowait(zio); } else { mutex_exit(hash_lock); } } kmem_free(cb, sizeof (l2arc_read_callback_t)); } /* * This is the list priority from which the L2ARC will search for pages to * cache. This is used within loops (0..3) to cycle through lists in the * desired order. This order can have a significant effect on cache * performance. * * Currently the metadata lists are hit first, MFU then MRU, followed by * the data lists. This function returns a locked list, and also returns * the lock pointer. */ static multilist_sublist_t * l2arc_sublist_lock(int list_num) { multilist_t *ml = NULL; unsigned int idx; ASSERT(list_num >= 0 && list_num < L2ARC_FEED_TYPES); switch (list_num) { case 0: ml = &arc_mfu->arcs_list[ARC_BUFC_METADATA]; break; case 1: ml = &arc_mru->arcs_list[ARC_BUFC_METADATA]; break; case 2: ml = &arc_mfu->arcs_list[ARC_BUFC_DATA]; break; case 3: ml = &arc_mru->arcs_list[ARC_BUFC_DATA]; break; default: return (NULL); } /* * Return a randomly-selected sublist. This is acceptable * because the caller feeds only a little bit of data for each * call (8MB). Subsequent calls will result in different * sublists being selected. */ idx = multilist_get_random_index(ml); return (multilist_sublist_lock(ml, idx)); } /* * Calculates the maximum overhead of L2ARC metadata log blocks for a given * L2ARC write size. l2arc_evict and l2arc_write_size need to include this * overhead in processing to make sure there is enough headroom available * when writing buffers. */ static inline uint64_t l2arc_log_blk_overhead(uint64_t write_sz, l2arc_dev_t *dev) { if (dev->l2ad_log_entries == 0) { return (0); } else { uint64_t log_entries = write_sz >> SPA_MINBLOCKSHIFT; uint64_t log_blocks = (log_entries + dev->l2ad_log_entries - 1) / dev->l2ad_log_entries; return (vdev_psize_to_asize(dev->l2ad_vdev, sizeof (l2arc_log_blk_phys_t)) * log_blocks); } } /* * Evict buffers from the device write hand to the distance specified in * bytes. This distance may span populated buffers, it may span nothing. * This is clearing a region on the L2ARC device ready for writing. * If the 'all' boolean is set, every buffer is evicted. */ static void l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) { list_t *buflist; arc_buf_hdr_t *hdr, *hdr_prev; kmutex_t *hash_lock; uint64_t taddr; l2arc_lb_ptr_buf_t *lb_ptr_buf, *lb_ptr_buf_prev; vdev_t *vd = dev->l2ad_vdev; boolean_t rerun; buflist = &dev->l2ad_buflist; /* * We need to add in the worst case scenario of log block overhead. */ distance += l2arc_log_blk_overhead(distance, dev); if (vd->vdev_has_trim && l2arc_trim_ahead > 0) { /* * Trim ahead of the write size 64MB or (l2arc_trim_ahead/100) * times the write size, whichever is greater. */ distance += MAX(64 * 1024 * 1024, (distance * l2arc_trim_ahead) / 100); } top: rerun = B_FALSE; if (dev->l2ad_hand >= (dev->l2ad_end - distance)) { /* * When there is no space to accommodate upcoming writes, * evict to the end. Then bump the write and evict hands * to the start and iterate. This iteration does not * happen indefinitely as we make sure in * l2arc_write_size() that when the write hand is reset, * the write size does not exceed the end of the device. */ rerun = B_TRUE; taddr = dev->l2ad_end; } else { taddr = dev->l2ad_hand + distance; } DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, uint64_t, taddr, boolean_t, all); if (!all) { /* * This check has to be placed after deciding whether to * iterate (rerun). */ if (dev->l2ad_first) { /* * This is the first sweep through the device. There is * nothing to evict. We have already trimmmed the * whole device. */ goto out; } else { /* * Trim the space to be evicted. */ if (vd->vdev_has_trim && dev->l2ad_evict < taddr && l2arc_trim_ahead > 0) { /* * We have to drop the spa_config lock because * vdev_trim_range() will acquire it. * l2ad_evict already accounts for the label * size. To prevent vdev_trim_ranges() from * adding it again, we subtract it from * l2ad_evict. */ spa_config_exit(dev->l2ad_spa, SCL_L2ARC, dev); vdev_trim_simple(vd, dev->l2ad_evict - VDEV_LABEL_START_SIZE, taddr - dev->l2ad_evict); spa_config_enter(dev->l2ad_spa, SCL_L2ARC, dev, RW_READER); } /* * When rebuilding L2ARC we retrieve the evict hand * from the header of the device. Of note, l2arc_evict() * does not actually delete buffers from the cache * device, but trimming may do so depending on the * hardware implementation. Thus keeping track of the * evict hand is useful. */ dev->l2ad_evict = MAX(dev->l2ad_evict, taddr); } } retry: mutex_enter(&dev->l2ad_mtx); /* * We have to account for evicted log blocks. Run vdev_space_update() * on log blocks whose offset (in bytes) is before the evicted offset * (in bytes) by searching in the list of pointers to log blocks * present in the L2ARC device. */ for (lb_ptr_buf = list_tail(&dev->l2ad_lbptr_list); lb_ptr_buf; lb_ptr_buf = lb_ptr_buf_prev) { lb_ptr_buf_prev = list_prev(&dev->l2ad_lbptr_list, lb_ptr_buf); /* L2BLK_GET_PSIZE returns aligned size for log blocks */ uint64_t asize = L2BLK_GET_PSIZE( (lb_ptr_buf->lb_ptr)->lbp_prop); /* * We don't worry about log blocks left behind (ie * lbp_payload_start < l2ad_hand) because l2arc_write_buffers() * will never write more than l2arc_evict() evicts. */ if (!all && l2arc_log_blkptr_valid(dev, lb_ptr_buf->lb_ptr)) { break; } else { vdev_space_update(vd, -asize, 0, 0); ARCSTAT_INCR(arcstat_l2_log_blk_asize, -asize); ARCSTAT_BUMPDOWN(arcstat_l2_log_blk_count); zfs_refcount_remove_many(&dev->l2ad_lb_asize, asize, lb_ptr_buf); zfs_refcount_remove(&dev->l2ad_lb_count, lb_ptr_buf); list_remove(&dev->l2ad_lbptr_list, lb_ptr_buf); kmem_free(lb_ptr_buf->lb_ptr, sizeof (l2arc_log_blkptr_t)); kmem_free(lb_ptr_buf, sizeof (l2arc_lb_ptr_buf_t)); } } for (hdr = list_tail(buflist); hdr; hdr = hdr_prev) { hdr_prev = list_prev(buflist, hdr); ASSERT(!HDR_EMPTY(hdr)); hash_lock = HDR_LOCK(hdr); /* * We cannot use mutex_enter or else we can deadlock * with l2arc_write_buffers (due to swapping the order * the hash lock and l2ad_mtx are taken). */ if (!mutex_tryenter(hash_lock)) { /* * Missed the hash lock. Retry. */ ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); mutex_exit(&dev->l2ad_mtx); mutex_enter(hash_lock); mutex_exit(hash_lock); goto retry; } /* * A header can't be on this list if it doesn't have L2 header. */ ASSERT(HDR_HAS_L2HDR(hdr)); /* Ensure this header has finished being written. */ ASSERT(!HDR_L2_WRITING(hdr)); ASSERT(!HDR_L2_WRITE_HEAD(hdr)); if (!all && (hdr->b_l2hdr.b_daddr >= dev->l2ad_evict || hdr->b_l2hdr.b_daddr < dev->l2ad_hand)) { /* * We've evicted to the target address, * or the end of the device. */ mutex_exit(hash_lock); break; } if (!HDR_HAS_L1HDR(hdr)) { ASSERT(!HDR_L2_READING(hdr)); /* * This doesn't exist in the ARC. Destroy. * arc_hdr_destroy() will call list_remove() * and decrement arcstat_l2_lsize. */ arc_change_state(arc_anon, hdr, hash_lock); arc_hdr_destroy(hdr); } else { ASSERT(hdr->b_l1hdr.b_state != arc_l2c_only); ARCSTAT_BUMP(arcstat_l2_evict_l1cached); /* * Invalidate issued or about to be issued * reads, since we may be about to write * over this location. */ if (HDR_L2_READING(hdr)) { ARCSTAT_BUMP(arcstat_l2_evict_reading); arc_hdr_set_flags(hdr, ARC_FLAG_L2_EVICTED); } arc_hdr_l2hdr_destroy(hdr); } mutex_exit(hash_lock); } mutex_exit(&dev->l2ad_mtx); out: /* * We need to check if we evict all buffers, otherwise we may iterate * unnecessarily. */ if (!all && rerun) { /* * Bump device hand to the device start if it is approaching the * end. l2arc_evict() has already evicted ahead for this case. */ dev->l2ad_hand = dev->l2ad_start; dev->l2ad_evict = dev->l2ad_start; dev->l2ad_first = B_FALSE; goto top; } if (!all) { /* * In case of cache device removal (all) the following * assertions may be violated without functional consequences * as the device is about to be removed. */ ASSERT3U(dev->l2ad_hand + distance, <, dev->l2ad_end); if (!dev->l2ad_first) ASSERT3U(dev->l2ad_hand, <, dev->l2ad_evict); } } /* * Handle any abd transforms that might be required for writing to the L2ARC. * If successful, this function will always return an abd with the data * transformed as it is on disk in a new abd of asize bytes. */ static int l2arc_apply_transforms(spa_t *spa, arc_buf_hdr_t *hdr, uint64_t asize, abd_t **abd_out) { int ret; void *tmp = NULL; abd_t *cabd = NULL, *eabd = NULL, *to_write = hdr->b_l1hdr.b_pabd; enum zio_compress compress = HDR_GET_COMPRESS(hdr); uint64_t psize = HDR_GET_PSIZE(hdr); uint64_t size = arc_hdr_size(hdr); boolean_t ismd = HDR_ISTYPE_METADATA(hdr); boolean_t bswap = (hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS); dsl_crypto_key_t *dck = NULL; uint8_t mac[ZIO_DATA_MAC_LEN] = { 0 }; boolean_t no_crypt = B_FALSE; ASSERT((HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr)) || HDR_ENCRYPTED(hdr) || HDR_SHARED_DATA(hdr) || psize != asize); ASSERT3U(psize, <=, asize); /* * If this data simply needs its own buffer, we simply allocate it * and copy the data. This may be done to eliminate a dependency on a * shared buffer or to reallocate the buffer to match asize. */ if (HDR_HAS_RABD(hdr) && asize != psize) { ASSERT3U(asize, >=, psize); to_write = abd_alloc_for_io(asize, ismd); abd_copy(to_write, hdr->b_crypt_hdr.b_rabd, psize); if (psize != asize) abd_zero_off(to_write, psize, asize - psize); goto out; } if ((compress == ZIO_COMPRESS_OFF || HDR_COMPRESSION_ENABLED(hdr)) && !HDR_ENCRYPTED(hdr)) { ASSERT3U(size, ==, psize); to_write = abd_alloc_for_io(asize, ismd); abd_copy(to_write, hdr->b_l1hdr.b_pabd, size); if (size != asize) abd_zero_off(to_write, size, asize - size); goto out; } if (compress != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr)) { /* * In some cases, we can wind up with size > asize, so * we need to opt for the larger allocation option here. * * (We also need abd_return_buf_copy in all cases because * it's an ASSERT() to modify the buffer before returning it * with arc_return_buf(), and all the compressors * write things before deciding to fail compression in nearly * every case.) */ cabd = abd_alloc_for_io(size, ismd); tmp = abd_borrow_buf(cabd, size); psize = zio_compress_data(compress, to_write, tmp, size, hdr->b_complevel); if (psize >= asize) { psize = HDR_GET_PSIZE(hdr); abd_return_buf_copy(cabd, tmp, size); HDR_SET_COMPRESS(hdr, ZIO_COMPRESS_OFF); to_write = cabd; abd_copy(to_write, hdr->b_l1hdr.b_pabd, psize); if (psize != asize) abd_zero_off(to_write, psize, asize - psize); goto encrypt; } ASSERT3U(psize, <=, HDR_GET_PSIZE(hdr)); if (psize < asize) memset((char *)tmp + psize, 0, asize - psize); psize = HDR_GET_PSIZE(hdr); abd_return_buf_copy(cabd, tmp, size); to_write = cabd; } encrypt: if (HDR_ENCRYPTED(hdr)) { eabd = abd_alloc_for_io(asize, ismd); /* * If the dataset was disowned before the buffer * made it to this point, the key to re-encrypt * it won't be available. In this case we simply * won't write the buffer to the L2ARC. */ ret = spa_keystore_lookup_key(spa, hdr->b_crypt_hdr.b_dsobj, FTAG, &dck); if (ret != 0) goto error; ret = zio_do_crypt_abd(B_TRUE, &dck->dck_key, hdr->b_crypt_hdr.b_ot, bswap, hdr->b_crypt_hdr.b_salt, hdr->b_crypt_hdr.b_iv, mac, psize, to_write, eabd, &no_crypt); if (ret != 0) goto error; if (no_crypt) abd_copy(eabd, to_write, psize); if (psize != asize) abd_zero_off(eabd, psize, asize - psize); /* assert that the MAC we got here matches the one we saved */ ASSERT0(memcmp(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN)); spa_keystore_dsl_key_rele(spa, dck, FTAG); if (to_write == cabd) abd_free(cabd); to_write = eabd; } out: ASSERT3P(to_write, !=, hdr->b_l1hdr.b_pabd); *abd_out = to_write; return (0); error: if (dck != NULL) spa_keystore_dsl_key_rele(spa, dck, FTAG); if (cabd != NULL) abd_free(cabd); if (eabd != NULL) abd_free(eabd); *abd_out = NULL; return (ret); } static void l2arc_blk_fetch_done(zio_t *zio) { l2arc_read_callback_t *cb; cb = zio->io_private; if (cb->l2rcb_abd != NULL) abd_free(cb->l2rcb_abd); kmem_free(cb, sizeof (l2arc_read_callback_t)); } /* * Find and write ARC buffers to the L2ARC device. * * An ARC_FLAG_L2_WRITING flag is set so that the L2ARC buffers are not valid * for reading until they have completed writing. * The headroom_boost is an in-out parameter used to maintain headroom boost * state between calls to this function. * * Returns the number of bytes actually written (which may be smaller than * the delta by which the device hand has changed due to alignment and the * writing of log blocks). */ static uint64_t l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) { arc_buf_hdr_t *hdr, *hdr_prev, *head; uint64_t write_asize, write_psize, write_lsize, headroom; boolean_t full; l2arc_write_callback_t *cb = NULL; zio_t *pio, *wzio; uint64_t guid = spa_load_guid(spa); l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr; ASSERT3P(dev->l2ad_vdev, !=, NULL); pio = NULL; write_lsize = write_asize = write_psize = 0; full = B_FALSE; head = kmem_cache_alloc(hdr_l2only_cache, KM_PUSHPAGE); arc_hdr_set_flags(head, ARC_FLAG_L2_WRITE_HEAD | ARC_FLAG_HAS_L2HDR); /* * Copy buffers for L2ARC writing. */ for (int pass = 0; pass < L2ARC_FEED_TYPES; pass++) { /* * If pass == 1 or 3, we cache MRU metadata and data * respectively. */ if (l2arc_mfuonly) { if (pass == 1 || pass == 3) continue; } multilist_sublist_t *mls = l2arc_sublist_lock(pass); uint64_t passed_sz = 0; VERIFY3P(mls, !=, NULL); /* * L2ARC fast warmup. * * Until the ARC is warm and starts to evict, read from the * head of the ARC lists rather than the tail. */ if (arc_warm == B_FALSE) hdr = multilist_sublist_head(mls); else hdr = multilist_sublist_tail(mls); headroom = target_sz * l2arc_headroom; if (zfs_compressed_arc_enabled) headroom = (headroom * l2arc_headroom_boost) / 100; for (; hdr; hdr = hdr_prev) { kmutex_t *hash_lock; abd_t *to_write = NULL; if (arc_warm == B_FALSE) hdr_prev = multilist_sublist_next(mls, hdr); else hdr_prev = multilist_sublist_prev(mls, hdr); hash_lock = HDR_LOCK(hdr); if (!mutex_tryenter(hash_lock)) { /* * Skip this buffer rather than waiting. */ continue; } passed_sz += HDR_GET_LSIZE(hdr); if (l2arc_headroom != 0 && passed_sz > headroom) { /* * Searched too far. */ mutex_exit(hash_lock); break; } if (!l2arc_write_eligible(guid, hdr)) { mutex_exit(hash_lock); continue; } ASSERT(HDR_HAS_L1HDR(hdr)); ASSERT3U(HDR_GET_PSIZE(hdr), >, 0); ASSERT3U(arc_hdr_size(hdr), >, 0); ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); uint64_t psize = HDR_GET_PSIZE(hdr); uint64_t asize = vdev_psize_to_asize(dev->l2ad_vdev, psize); if ((write_asize + asize) > target_sz) { full = B_TRUE; mutex_exit(hash_lock); break; } /* * We rely on the L1 portion of the header below, so * it's invalid for this header to have been evicted out * of the ghost cache, prior to being written out. The * ARC_FLAG_L2_WRITING bit ensures this won't happen. */ arc_hdr_set_flags(hdr, ARC_FLAG_L2_WRITING); /* * If this header has b_rabd, we can use this since it * must always match the data exactly as it exists on * disk. Otherwise, the L2ARC can normally use the * hdr's data, but if we're sharing data between the * hdr and one of its bufs, L2ARC needs its own copy of * the data so that the ZIO below can't race with the * buf consumer. To ensure that this copy will be * available for the lifetime of the ZIO and be cleaned * up afterwards, we add it to the l2arc_free_on_write * queue. If we need to apply any transforms to the * data (compression, encryption) we will also need the * extra buffer. */ if (HDR_HAS_RABD(hdr) && psize == asize) { to_write = hdr->b_crypt_hdr.b_rabd; } else if ((HDR_COMPRESSION_ENABLED(hdr) || HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_OFF) && !HDR_ENCRYPTED(hdr) && !HDR_SHARED_DATA(hdr) && psize == asize) { to_write = hdr->b_l1hdr.b_pabd; } else { int ret; arc_buf_contents_t type = arc_buf_type(hdr); ret = l2arc_apply_transforms(spa, hdr, asize, &to_write); if (ret != 0) { arc_hdr_clear_flags(hdr, ARC_FLAG_L2_WRITING); mutex_exit(hash_lock); continue; } l2arc_free_abd_on_write(to_write, asize, type); } if (pio == NULL) { /* * Insert a dummy header on the buflist so * l2arc_write_done() can find where the * write buffers begin without searching. */ mutex_enter(&dev->l2ad_mtx); list_insert_head(&dev->l2ad_buflist, head); mutex_exit(&dev->l2ad_mtx); cb = kmem_alloc( sizeof (l2arc_write_callback_t), KM_SLEEP); cb->l2wcb_dev = dev; cb->l2wcb_head = head; /* * Create a list to save allocated abd buffers * for l2arc_log_blk_commit(). */ list_create(&cb->l2wcb_abd_list, sizeof (l2arc_lb_abd_buf_t), offsetof(l2arc_lb_abd_buf_t, node)); pio = zio_root(spa, l2arc_write_done, cb, ZIO_FLAG_CANFAIL); } hdr->b_l2hdr.b_dev = dev; hdr->b_l2hdr.b_hits = 0; hdr->b_l2hdr.b_daddr = dev->l2ad_hand; hdr->b_l2hdr.b_arcs_state = hdr->b_l1hdr.b_state->arcs_state; arc_hdr_set_flags(hdr, ARC_FLAG_HAS_L2HDR); mutex_enter(&dev->l2ad_mtx); list_insert_head(&dev->l2ad_buflist, hdr); mutex_exit(&dev->l2ad_mtx); (void) zfs_refcount_add_many(&dev->l2ad_alloc, arc_hdr_size(hdr), hdr); wzio = zio_write_phys(pio, dev->l2ad_vdev, hdr->b_l2hdr.b_daddr, asize, to_write, ZIO_CHECKSUM_OFF, NULL, hdr, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_CANFAIL, B_FALSE); write_lsize += HDR_GET_LSIZE(hdr); DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, zio_t *, wzio); write_psize += psize; write_asize += asize; dev->l2ad_hand += asize; l2arc_hdr_arcstats_increment(hdr); vdev_space_update(dev->l2ad_vdev, asize, 0, 0); mutex_exit(hash_lock); /* * Append buf info to current log and commit if full. * arcstat_l2_{size,asize} kstats are updated * internally. */ if (l2arc_log_blk_insert(dev, hdr)) l2arc_log_blk_commit(dev, pio, cb); zio_nowait(wzio); } multilist_sublist_unlock(mls); if (full == B_TRUE) break; } /* No buffers selected for writing? */ if (pio == NULL) { ASSERT0(write_lsize); ASSERT(!HDR_HAS_L1HDR(head)); kmem_cache_free(hdr_l2only_cache, head); /* * Although we did not write any buffers l2ad_evict may * have advanced. */ if (dev->l2ad_evict != l2dhdr->dh_evict) l2arc_dev_hdr_update(dev); return (0); } if (!dev->l2ad_first) ASSERT3U(dev->l2ad_hand, <=, dev->l2ad_evict); ASSERT3U(write_asize, <=, target_sz); ARCSTAT_BUMP(arcstat_l2_writes_sent); ARCSTAT_INCR(arcstat_l2_write_bytes, write_psize); dev->l2ad_writing = B_TRUE; (void) zio_wait(pio); dev->l2ad_writing = B_FALSE; /* * Update the device header after the zio completes as * l2arc_write_done() may have updated the memory holding the log block * pointers in the device header. */ l2arc_dev_hdr_update(dev); return (write_asize); } static boolean_t l2arc_hdr_limit_reached(void) { int64_t s = aggsum_upper_bound(&arc_sums.arcstat_l2_hdr_size); return (arc_reclaim_needed() || (s > arc_meta_limit * 3 / 4) || (s > (arc_warm ? arc_c : arc_c_max) * l2arc_meta_percent / 100)); } /* * This thread feeds the L2ARC at regular intervals. This is the beating * heart of the L2ARC. */ static __attribute__((noreturn)) void l2arc_feed_thread(void *unused) { (void) unused; callb_cpr_t cpr; l2arc_dev_t *dev; spa_t *spa; uint64_t size, wrote; clock_t begin, next = ddi_get_lbolt(); fstrans_cookie_t cookie; CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); mutex_enter(&l2arc_feed_thr_lock); cookie = spl_fstrans_mark(); while (l2arc_thread_exit == 0) { CALLB_CPR_SAFE_BEGIN(&cpr); (void) cv_timedwait_idle(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock, next); CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); next = ddi_get_lbolt() + hz; /* * Quick check for L2ARC devices. */ mutex_enter(&l2arc_dev_mtx); if (l2arc_ndev == 0) { mutex_exit(&l2arc_dev_mtx); continue; } mutex_exit(&l2arc_dev_mtx); begin = ddi_get_lbolt(); /* * This selects the next l2arc device to write to, and in * doing so the next spa to feed from: dev->l2ad_spa. This * will return NULL if there are now no l2arc devices or if * they are all faulted. * * If a device is returned, its spa's config lock is also * held to prevent device removal. l2arc_dev_get_next() * will grab and release l2arc_dev_mtx. */ if ((dev = l2arc_dev_get_next()) == NULL) continue; spa = dev->l2ad_spa; ASSERT3P(spa, !=, NULL); /* * If the pool is read-only then force the feed thread to * sleep a little longer. */ if (!spa_writeable(spa)) { next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz; spa_config_exit(spa, SCL_L2ARC, dev); continue; } /* * Avoid contributing to memory pressure. */ if (l2arc_hdr_limit_reached()) { ARCSTAT_BUMP(arcstat_l2_abort_lowmem); spa_config_exit(spa, SCL_L2ARC, dev); continue; } ARCSTAT_BUMP(arcstat_l2_feeds); size = l2arc_write_size(dev); /* * Evict L2ARC buffers that will be overwritten. */ l2arc_evict(dev, size, B_FALSE); /* * Write ARC buffers. */ wrote = l2arc_write_buffers(spa, dev, size); /* * Calculate interval between writes. */ next = l2arc_write_interval(begin, size, wrote); spa_config_exit(spa, SCL_L2ARC, dev); } spl_fstrans_unmark(cookie); l2arc_thread_exit = 0; cv_broadcast(&l2arc_feed_thr_cv); CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ thread_exit(); } boolean_t l2arc_vdev_present(vdev_t *vd) { return (l2arc_vdev_get(vd) != NULL); } /* * Returns the l2arc_dev_t associated with a particular vdev_t or NULL if * the vdev_t isn't an L2ARC device. */ l2arc_dev_t * l2arc_vdev_get(vdev_t *vd) { l2arc_dev_t *dev; mutex_enter(&l2arc_dev_mtx); for (dev = list_head(l2arc_dev_list); dev != NULL; dev = list_next(l2arc_dev_list, dev)) { if (dev->l2ad_vdev == vd) break; } mutex_exit(&l2arc_dev_mtx); return (dev); } static void l2arc_rebuild_dev(l2arc_dev_t *dev, boolean_t reopen) { l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr; uint64_t l2dhdr_asize = dev->l2ad_dev_hdr_asize; spa_t *spa = dev->l2ad_spa; /* * The L2ARC has to hold at least the payload of one log block for * them to be restored (persistent L2ARC). The payload of a log block * depends on the amount of its log entries. We always write log blocks * with 1022 entries. How many of them are committed or restored depends * on the size of the L2ARC device. Thus the maximum payload of * one log block is 1022 * SPA_MAXBLOCKSIZE = 16GB. If the L2ARC device * is less than that, we reduce the amount of committed and restored * log entries per block so as to enable persistence. */ if (dev->l2ad_end < l2arc_rebuild_blocks_min_l2size) { dev->l2ad_log_entries = 0; } else { dev->l2ad_log_entries = MIN((dev->l2ad_end - dev->l2ad_start) >> SPA_MAXBLOCKSHIFT, L2ARC_LOG_BLK_MAX_ENTRIES); } /* * Read the device header, if an error is returned do not rebuild L2ARC. */ if (l2arc_dev_hdr_read(dev) == 0 && dev->l2ad_log_entries > 0) { /* * If we are onlining a cache device (vdev_reopen) that was * still present (l2arc_vdev_present()) and rebuild is enabled, * we should evict all ARC buffers and pointers to log blocks * and reclaim their space before restoring its contents to * L2ARC. */ if (reopen) { if (!l2arc_rebuild_enabled) { return; } else { l2arc_evict(dev, 0, B_TRUE); /* start a new log block */ dev->l2ad_log_ent_idx = 0; dev->l2ad_log_blk_payload_asize = 0; dev->l2ad_log_blk_payload_start = 0; } } /* * Just mark the device as pending for a rebuild. We won't * be starting a rebuild in line here as it would block pool * import. Instead spa_load_impl will hand that off to an * async task which will call l2arc_spa_rebuild_start. */ dev->l2ad_rebuild = B_TRUE; } else if (spa_writeable(spa)) { /* * In this case TRIM the whole device if l2arc_trim_ahead > 0, * otherwise create a new header. We zero out the memory holding * the header to reset dh_start_lbps. If we TRIM the whole * device the new header will be written by * vdev_trim_l2arc_thread() at the end of the TRIM to update the * trim_state in the header too. When reading the header, if * trim_state is not VDEV_TRIM_COMPLETE and l2arc_trim_ahead > 0 * we opt to TRIM the whole device again. */ if (l2arc_trim_ahead > 0) { dev->l2ad_trim_all = B_TRUE; } else { memset(l2dhdr, 0, l2dhdr_asize); l2arc_dev_hdr_update(dev); } } } /* * Add a vdev for use by the L2ARC. By this point the spa has already * validated the vdev and opened it. */ void l2arc_add_vdev(spa_t *spa, vdev_t *vd) { l2arc_dev_t *adddev; uint64_t l2dhdr_asize; ASSERT(!l2arc_vdev_present(vd)); /* * Create a new l2arc device entry. */ adddev = vmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); adddev->l2ad_spa = spa; adddev->l2ad_vdev = vd; /* leave extra size for an l2arc device header */ l2dhdr_asize = adddev->l2ad_dev_hdr_asize = MAX(sizeof (*adddev->l2ad_dev_hdr), 1 << vd->vdev_ashift); adddev->l2ad_start = VDEV_LABEL_START_SIZE + l2dhdr_asize; adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); ASSERT3U(adddev->l2ad_start, <, adddev->l2ad_end); adddev->l2ad_hand = adddev->l2ad_start; adddev->l2ad_evict = adddev->l2ad_start; adddev->l2ad_first = B_TRUE; adddev->l2ad_writing = B_FALSE; adddev->l2ad_trim_all = B_FALSE; list_link_init(&adddev->l2ad_node); adddev->l2ad_dev_hdr = kmem_zalloc(l2dhdr_asize, KM_SLEEP); mutex_init(&adddev->l2ad_mtx, NULL, MUTEX_DEFAULT, NULL); /* * This is a list of all ARC buffers that are still valid on the * device. */ list_create(&adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), offsetof(arc_buf_hdr_t, b_l2hdr.b_l2node)); /* * This is a list of pointers to log blocks that are still present * on the device. */ list_create(&adddev->l2ad_lbptr_list, sizeof (l2arc_lb_ptr_buf_t), offsetof(l2arc_lb_ptr_buf_t, node)); vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); zfs_refcount_create(&adddev->l2ad_alloc); zfs_refcount_create(&adddev->l2ad_lb_asize); zfs_refcount_create(&adddev->l2ad_lb_count); /* * Decide if dev is eligible for L2ARC rebuild or whole device * trimming. This has to happen before the device is added in the * cache device list and l2arc_dev_mtx is released. Otherwise * l2arc_feed_thread() might already start writing on the * device. */ l2arc_rebuild_dev(adddev, B_FALSE); /* * Add device to global list */ mutex_enter(&l2arc_dev_mtx); list_insert_head(l2arc_dev_list, adddev); atomic_inc_64(&l2arc_ndev); mutex_exit(&l2arc_dev_mtx); } /* * Decide if a vdev is eligible for L2ARC rebuild, called from vdev_reopen() * in case of onlining a cache device. */ void l2arc_rebuild_vdev(vdev_t *vd, boolean_t reopen) { l2arc_dev_t *dev = NULL; dev = l2arc_vdev_get(vd); ASSERT3P(dev, !=, NULL); /* * In contrast to l2arc_add_vdev() we do not have to worry about * l2arc_feed_thread() invalidating previous content when onlining a * cache device. The device parameters (l2ad*) are not cleared when * offlining the device and writing new buffers will not invalidate * all previous content. In worst case only buffers that have not had * their log block written to the device will be lost. * When onlining the cache device (ie offline->online without exporting * the pool in between) this happens: * vdev_reopen() -> vdev_open() -> l2arc_rebuild_vdev() * | | * vdev_is_dead() = B_FALSE l2ad_rebuild = B_TRUE * During the time where vdev_is_dead = B_FALSE and until l2ad_rebuild * is set to B_TRUE we might write additional buffers to the device. */ l2arc_rebuild_dev(dev, reopen); } /* * Remove a vdev from the L2ARC. */ void l2arc_remove_vdev(vdev_t *vd) { l2arc_dev_t *remdev = NULL; /* * Find the device by vdev */ remdev = l2arc_vdev_get(vd); ASSERT3P(remdev, !=, NULL); /* * Cancel any ongoing or scheduled rebuild. */ mutex_enter(&l2arc_rebuild_thr_lock); if (remdev->l2ad_rebuild_began == B_TRUE) { remdev->l2ad_rebuild_cancel = B_TRUE; while (remdev->l2ad_rebuild == B_TRUE) cv_wait(&l2arc_rebuild_thr_cv, &l2arc_rebuild_thr_lock); } mutex_exit(&l2arc_rebuild_thr_lock); /* * Remove device from global list */ mutex_enter(&l2arc_dev_mtx); list_remove(l2arc_dev_list, remdev); l2arc_dev_last = NULL; /* may have been invalidated */ atomic_dec_64(&l2arc_ndev); mutex_exit(&l2arc_dev_mtx); /* * Clear all buflists and ARC references. L2ARC device flush. */ l2arc_evict(remdev, 0, B_TRUE); list_destroy(&remdev->l2ad_buflist); ASSERT(list_is_empty(&remdev->l2ad_lbptr_list)); list_destroy(&remdev->l2ad_lbptr_list); mutex_destroy(&remdev->l2ad_mtx); zfs_refcount_destroy(&remdev->l2ad_alloc); zfs_refcount_destroy(&remdev->l2ad_lb_asize); zfs_refcount_destroy(&remdev->l2ad_lb_count); kmem_free(remdev->l2ad_dev_hdr, remdev->l2ad_dev_hdr_asize); vmem_free(remdev, sizeof (l2arc_dev_t)); } void l2arc_init(void) { l2arc_thread_exit = 0; l2arc_ndev = 0; mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); mutex_init(&l2arc_rebuild_thr_lock, NULL, MUTEX_DEFAULT, NULL); cv_init(&l2arc_rebuild_thr_cv, NULL, CV_DEFAULT, NULL); mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); l2arc_dev_list = &L2ARC_dev_list; l2arc_free_on_write = &L2ARC_free_on_write; list_create(l2arc_dev_list, sizeof (l2arc_dev_t), offsetof(l2arc_dev_t, l2ad_node)); list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), offsetof(l2arc_data_free_t, l2df_list_node)); } void l2arc_fini(void) { mutex_destroy(&l2arc_feed_thr_lock); cv_destroy(&l2arc_feed_thr_cv); mutex_destroy(&l2arc_rebuild_thr_lock); cv_destroy(&l2arc_rebuild_thr_cv); mutex_destroy(&l2arc_dev_mtx); mutex_destroy(&l2arc_free_on_write_mtx); list_destroy(l2arc_dev_list); list_destroy(l2arc_free_on_write); } void l2arc_start(void) { if (!(spa_mode_global & SPA_MODE_WRITE)) return; (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, TS_RUN, defclsyspri); } void l2arc_stop(void) { if (!(spa_mode_global & SPA_MODE_WRITE)) return; mutex_enter(&l2arc_feed_thr_lock); cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ l2arc_thread_exit = 1; while (l2arc_thread_exit != 0) cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); mutex_exit(&l2arc_feed_thr_lock); } /* * Punches out rebuild threads for the L2ARC devices in a spa. This should * be called after pool import from the spa async thread, since starting * these threads directly from spa_import() will make them part of the * "zpool import" context and delay process exit (and thus pool import). */ void l2arc_spa_rebuild_start(spa_t *spa) { ASSERT(MUTEX_HELD(&spa_namespace_lock)); /* * Locate the spa's l2arc devices and kick off rebuild threads. */ for (int i = 0; i < spa->spa_l2cache.sav_count; i++) { l2arc_dev_t *dev = l2arc_vdev_get(spa->spa_l2cache.sav_vdevs[i]); if (dev == NULL) { /* Don't attempt a rebuild if the vdev is UNAVAIL */ continue; } mutex_enter(&l2arc_rebuild_thr_lock); if (dev->l2ad_rebuild && !dev->l2ad_rebuild_cancel) { dev->l2ad_rebuild_began = B_TRUE; (void) thread_create(NULL, 0, l2arc_dev_rebuild_thread, dev, 0, &p0, TS_RUN, minclsyspri); } mutex_exit(&l2arc_rebuild_thr_lock); } } /* * Main entry point for L2ARC rebuilding. */ static __attribute__((noreturn)) void l2arc_dev_rebuild_thread(void *arg) { l2arc_dev_t *dev = arg; VERIFY(!dev->l2ad_rebuild_cancel); VERIFY(dev->l2ad_rebuild); (void) l2arc_rebuild(dev); mutex_enter(&l2arc_rebuild_thr_lock); dev->l2ad_rebuild_began = B_FALSE; dev->l2ad_rebuild = B_FALSE; mutex_exit(&l2arc_rebuild_thr_lock); thread_exit(); } /* * This function implements the actual L2ARC metadata rebuild. It: * starts reading the log block chain and restores each block's contents * to memory (reconstructing arc_buf_hdr_t's). * * Operation stops under any of the following conditions: * * 1) We reach the end of the log block chain. * 2) We encounter *any* error condition (cksum errors, io errors) */ static int l2arc_rebuild(l2arc_dev_t *dev) { vdev_t *vd = dev->l2ad_vdev; spa_t *spa = vd->vdev_spa; int err = 0; l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr; l2arc_log_blk_phys_t *this_lb, *next_lb; zio_t *this_io = NULL, *next_io = NULL; l2arc_log_blkptr_t lbps[2]; l2arc_lb_ptr_buf_t *lb_ptr_buf; boolean_t lock_held; this_lb = vmem_zalloc(sizeof (*this_lb), KM_SLEEP); next_lb = vmem_zalloc(sizeof (*next_lb), KM_SLEEP); /* * We prevent device removal while issuing reads to the device, * then during the rebuilding phases we drop this lock again so * that a spa_unload or device remove can be initiated - this is * safe, because the spa will signal us to stop before removing * our device and wait for us to stop. */ spa_config_enter(spa, SCL_L2ARC, vd, RW_READER); lock_held = B_TRUE; /* * Retrieve the persistent L2ARC device state. * L2BLK_GET_PSIZE returns aligned size for log blocks. */ dev->l2ad_evict = MAX(l2dhdr->dh_evict, dev->l2ad_start); dev->l2ad_hand = MAX(l2dhdr->dh_start_lbps[0].lbp_daddr + L2BLK_GET_PSIZE((&l2dhdr->dh_start_lbps[0])->lbp_prop), dev->l2ad_start); dev->l2ad_first = !!(l2dhdr->dh_flags & L2ARC_DEV_HDR_EVICT_FIRST); vd->vdev_trim_action_time = l2dhdr->dh_trim_action_time; vd->vdev_trim_state = l2dhdr->dh_trim_state; /* * In case the zfs module parameter l2arc_rebuild_enabled is false * we do not start the rebuild process. */ if (!l2arc_rebuild_enabled) goto out; /* Prepare the rebuild process */ memcpy(lbps, l2dhdr->dh_start_lbps, sizeof (lbps)); /* Start the rebuild process */ for (;;) { if (!l2arc_log_blkptr_valid(dev, &lbps[0])) break; if ((err = l2arc_log_blk_read(dev, &lbps[0], &lbps[1], this_lb, next_lb, this_io, &next_io)) != 0) goto out; /* * Our memory pressure valve. If the system is running low * on memory, rather than swamping memory with new ARC buf * hdrs, we opt not to rebuild the L2ARC. At this point, * however, we have already set up our L2ARC dev to chain in * new metadata log blocks, so the user may choose to offline/ * online the L2ARC dev at a later time (or re-import the pool) * to reconstruct it (when there's less memory pressure). */ if (l2arc_hdr_limit_reached()) { ARCSTAT_BUMP(arcstat_l2_rebuild_abort_lowmem); cmn_err(CE_NOTE, "System running low on memory, " "aborting L2ARC rebuild."); err = SET_ERROR(ENOMEM); goto out; } spa_config_exit(spa, SCL_L2ARC, vd); lock_held = B_FALSE; /* * Now that we know that the next_lb checks out alright, we * can start reconstruction from this log block. * L2BLK_GET_PSIZE returns aligned size for log blocks. */ uint64_t asize = L2BLK_GET_PSIZE((&lbps[0])->lbp_prop); l2arc_log_blk_restore(dev, this_lb, asize); /* * log block restored, include its pointer in the list of * pointers to log blocks present in the L2ARC device. */ lb_ptr_buf = kmem_zalloc(sizeof (l2arc_lb_ptr_buf_t), KM_SLEEP); lb_ptr_buf->lb_ptr = kmem_zalloc(sizeof (l2arc_log_blkptr_t), KM_SLEEP); memcpy(lb_ptr_buf->lb_ptr, &lbps[0], sizeof (l2arc_log_blkptr_t)); mutex_enter(&dev->l2ad_mtx); list_insert_tail(&dev->l2ad_lbptr_list, lb_ptr_buf); ARCSTAT_INCR(arcstat_l2_log_blk_asize, asize); ARCSTAT_BUMP(arcstat_l2_log_blk_count); zfs_refcount_add_many(&dev->l2ad_lb_asize, asize, lb_ptr_buf); zfs_refcount_add(&dev->l2ad_lb_count, lb_ptr_buf); mutex_exit(&dev->l2ad_mtx); vdev_space_update(vd, asize, 0, 0); /* * Protection against loops of log blocks: * * l2ad_hand l2ad_evict * V V * l2ad_start |=======================================| l2ad_end * -----|||----|||---|||----||| * (3) (2) (1) (0) * ---|||---|||----|||---||| * (7) (6) (5) (4) * * In this situation the pointer of log block (4) passes * l2arc_log_blkptr_valid() but the log block should not be * restored as it is overwritten by the payload of log block * (0). Only log blocks (0)-(3) should be restored. We check * whether l2ad_evict lies in between the payload starting * offset of the next log block (lbps[1].lbp_payload_start) * and the payload starting offset of the present log block * (lbps[0].lbp_payload_start). If true and this isn't the * first pass, we are looping from the beginning and we should * stop. */ if (l2arc_range_check_overlap(lbps[1].lbp_payload_start, lbps[0].lbp_payload_start, dev->l2ad_evict) && !dev->l2ad_first) goto out; - cond_resched(); + kpreempt(KPREEMPT_SYNC); for (;;) { mutex_enter(&l2arc_rebuild_thr_lock); if (dev->l2ad_rebuild_cancel) { dev->l2ad_rebuild = B_FALSE; cv_signal(&l2arc_rebuild_thr_cv); mutex_exit(&l2arc_rebuild_thr_lock); err = SET_ERROR(ECANCELED); goto out; } mutex_exit(&l2arc_rebuild_thr_lock); if (spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) { lock_held = B_TRUE; break; } /* * L2ARC config lock held by somebody in writer, * possibly due to them trying to remove us. They'll * likely to want us to shut down, so after a little * delay, we check l2ad_rebuild_cancel and retry * the lock again. */ delay(1); } /* * Continue with the next log block. */ lbps[0] = lbps[1]; lbps[1] = this_lb->lb_prev_lbp; PTR_SWAP(this_lb, next_lb); this_io = next_io; next_io = NULL; } if (this_io != NULL) l2arc_log_blk_fetch_abort(this_io); out: if (next_io != NULL) l2arc_log_blk_fetch_abort(next_io); vmem_free(this_lb, sizeof (*this_lb)); vmem_free(next_lb, sizeof (*next_lb)); if (!l2arc_rebuild_enabled) { spa_history_log_internal(spa, "L2ARC rebuild", NULL, "disabled"); } else if (err == 0 && zfs_refcount_count(&dev->l2ad_lb_count) > 0) { ARCSTAT_BUMP(arcstat_l2_rebuild_success); spa_history_log_internal(spa, "L2ARC rebuild", NULL, "successful, restored %llu blocks", (u_longlong_t)zfs_refcount_count(&dev->l2ad_lb_count)); } else if (err == 0 && zfs_refcount_count(&dev->l2ad_lb_count) == 0) { /* * No error but also nothing restored, meaning the lbps array * in the device header points to invalid/non-present log * blocks. Reset the header. */ spa_history_log_internal(spa, "L2ARC rebuild", NULL, "no valid log blocks"); memset(l2dhdr, 0, dev->l2ad_dev_hdr_asize); l2arc_dev_hdr_update(dev); } else if (err == ECANCELED) { /* * In case the rebuild was canceled do not log to spa history * log as the pool may be in the process of being removed. */ zfs_dbgmsg("L2ARC rebuild aborted, restored %llu blocks", (u_longlong_t)zfs_refcount_count(&dev->l2ad_lb_count)); } else if (err != 0) { spa_history_log_internal(spa, "L2ARC rebuild", NULL, "aborted, restored %llu blocks", (u_longlong_t)zfs_refcount_count(&dev->l2ad_lb_count)); } if (lock_held) spa_config_exit(spa, SCL_L2ARC, vd); return (err); } /* * Attempts to read the device header on the provided L2ARC device and writes * it to `hdr'. On success, this function returns 0, otherwise the appropriate * error code is returned. */ static int l2arc_dev_hdr_read(l2arc_dev_t *dev) { int err; uint64_t guid; l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr; const uint64_t l2dhdr_asize = dev->l2ad_dev_hdr_asize; abd_t *abd; guid = spa_guid(dev->l2ad_vdev->vdev_spa); abd = abd_get_from_buf(l2dhdr, l2dhdr_asize); err = zio_wait(zio_read_phys(NULL, dev->l2ad_vdev, VDEV_LABEL_START_SIZE, l2dhdr_asize, abd, ZIO_CHECKSUM_LABEL, NULL, NULL, ZIO_PRIORITY_SYNC_READ, ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY | ZIO_FLAG_SPECULATIVE, B_FALSE)); abd_free(abd); if (err != 0) { ARCSTAT_BUMP(arcstat_l2_rebuild_abort_dh_errors); zfs_dbgmsg("L2ARC IO error (%d) while reading device header, " "vdev guid: %llu", err, (u_longlong_t)dev->l2ad_vdev->vdev_guid); return (err); } if (l2dhdr->dh_magic == BSWAP_64(L2ARC_DEV_HDR_MAGIC)) byteswap_uint64_array(l2dhdr, sizeof (*l2dhdr)); if (l2dhdr->dh_magic != L2ARC_DEV_HDR_MAGIC || l2dhdr->dh_spa_guid != guid || l2dhdr->dh_vdev_guid != dev->l2ad_vdev->vdev_guid || l2dhdr->dh_version != L2ARC_PERSISTENT_VERSION || l2dhdr->dh_log_entries != dev->l2ad_log_entries || l2dhdr->dh_end != dev->l2ad_end || !l2arc_range_check_overlap(dev->l2ad_start, dev->l2ad_end, l2dhdr->dh_evict) || (l2dhdr->dh_trim_state != VDEV_TRIM_COMPLETE && l2arc_trim_ahead > 0)) { /* * Attempt to rebuild a device containing no actual dev hdr * or containing a header from some other pool or from another * version of persistent L2ARC. */ ARCSTAT_BUMP(arcstat_l2_rebuild_abort_unsupported); return (SET_ERROR(ENOTSUP)); } return (0); } /* * Reads L2ARC log blocks from storage and validates their contents. * * This function implements a simple fetcher to make sure that while * we're processing one buffer the L2ARC is already fetching the next * one in the chain. * * The arguments this_lp and next_lp point to the current and next log block * address in the block chain. Similarly, this_lb and next_lb hold the * l2arc_log_blk_phys_t's of the current and next L2ARC blk. * * The `this_io' and `next_io' arguments are used for block fetching. * When issuing the first blk IO during rebuild, you should pass NULL for * `this_io'. This function will then issue a sync IO to read the block and * also issue an async IO to fetch the next block in the block chain. The * fetched IO is returned in `next_io'. On subsequent calls to this * function, pass the value returned in `next_io' from the previous call * as `this_io' and a fresh `next_io' pointer to hold the next fetch IO. * Prior to the call, you should initialize your `next_io' pointer to be * NULL. If no fetch IO was issued, the pointer is left set at NULL. * * On success, this function returns 0, otherwise it returns an appropriate * error code. On error the fetching IO is aborted and cleared before * returning from this function. Therefore, if we return `success', the * caller can assume that we have taken care of cleanup of fetch IOs. */ static int l2arc_log_blk_read(l2arc_dev_t *dev, const l2arc_log_blkptr_t *this_lbp, const l2arc_log_blkptr_t *next_lbp, l2arc_log_blk_phys_t *this_lb, l2arc_log_blk_phys_t *next_lb, zio_t *this_io, zio_t **next_io) { int err = 0; zio_cksum_t cksum; abd_t *abd = NULL; uint64_t asize; ASSERT(this_lbp != NULL && next_lbp != NULL); ASSERT(this_lb != NULL && next_lb != NULL); ASSERT(next_io != NULL && *next_io == NULL); ASSERT(l2arc_log_blkptr_valid(dev, this_lbp)); /* * Check to see if we have issued the IO for this log block in a * previous run. If not, this is the first call, so issue it now. */ if (this_io == NULL) { this_io = l2arc_log_blk_fetch(dev->l2ad_vdev, this_lbp, this_lb); } /* * Peek to see if we can start issuing the next IO immediately. */ if (l2arc_log_blkptr_valid(dev, next_lbp)) { /* * Start issuing IO for the next log block early - this * should help keep the L2ARC device busy while we * decompress and restore this log block. */ *next_io = l2arc_log_blk_fetch(dev->l2ad_vdev, next_lbp, next_lb); } /* Wait for the IO to read this log block to complete */ if ((err = zio_wait(this_io)) != 0) { ARCSTAT_BUMP(arcstat_l2_rebuild_abort_io_errors); zfs_dbgmsg("L2ARC IO error (%d) while reading log block, " "offset: %llu, vdev guid: %llu", err, (u_longlong_t)this_lbp->lbp_daddr, (u_longlong_t)dev->l2ad_vdev->vdev_guid); goto cleanup; } /* * Make sure the buffer checks out. * L2BLK_GET_PSIZE returns aligned size for log blocks. */ asize = L2BLK_GET_PSIZE((this_lbp)->lbp_prop); fletcher_4_native(this_lb, asize, NULL, &cksum); if (!ZIO_CHECKSUM_EQUAL(cksum, this_lbp->lbp_cksum)) { ARCSTAT_BUMP(arcstat_l2_rebuild_abort_cksum_lb_errors); zfs_dbgmsg("L2ARC log block cksum failed, offset: %llu, " "vdev guid: %llu, l2ad_hand: %llu, l2ad_evict: %llu", (u_longlong_t)this_lbp->lbp_daddr, (u_longlong_t)dev->l2ad_vdev->vdev_guid, (u_longlong_t)dev->l2ad_hand, (u_longlong_t)dev->l2ad_evict); err = SET_ERROR(ECKSUM); goto cleanup; } /* Now we can take our time decoding this buffer */ switch (L2BLK_GET_COMPRESS((this_lbp)->lbp_prop)) { case ZIO_COMPRESS_OFF: break; case ZIO_COMPRESS_LZ4: abd = abd_alloc_for_io(asize, B_TRUE); abd_copy_from_buf_off(abd, this_lb, 0, asize); if ((err = zio_decompress_data( L2BLK_GET_COMPRESS((this_lbp)->lbp_prop), abd, this_lb, asize, sizeof (*this_lb), NULL)) != 0) { err = SET_ERROR(EINVAL); goto cleanup; } break; default: err = SET_ERROR(EINVAL); goto cleanup; } if (this_lb->lb_magic == BSWAP_64(L2ARC_LOG_BLK_MAGIC)) byteswap_uint64_array(this_lb, sizeof (*this_lb)); if (this_lb->lb_magic != L2ARC_LOG_BLK_MAGIC) { err = SET_ERROR(EINVAL); goto cleanup; } cleanup: /* Abort an in-flight fetch I/O in case of error */ if (err != 0 && *next_io != NULL) { l2arc_log_blk_fetch_abort(*next_io); *next_io = NULL; } if (abd != NULL) abd_free(abd); return (err); } /* * Restores the payload of a log block to ARC. This creates empty ARC hdr * entries which only contain an l2arc hdr, essentially restoring the * buffers to their L2ARC evicted state. This function also updates space * usage on the L2ARC vdev to make sure it tracks restored buffers. */ static void l2arc_log_blk_restore(l2arc_dev_t *dev, const l2arc_log_blk_phys_t *lb, uint64_t lb_asize) { uint64_t size = 0, asize = 0; uint64_t log_entries = dev->l2ad_log_entries; /* * Usually arc_adapt() is called only for data, not headers, but * since we may allocate significant amount of memory here, let ARC * grow its arc_c. */ arc_adapt(log_entries * HDR_L2ONLY_SIZE, arc_l2c_only); for (int i = log_entries - 1; i >= 0; i--) { /* * Restore goes in the reverse temporal direction to preserve * correct temporal ordering of buffers in the l2ad_buflist. * l2arc_hdr_restore also does a list_insert_tail instead of * list_insert_head on the l2ad_buflist: * * LIST l2ad_buflist LIST * HEAD <------ (time) ------ TAIL * direction +-----+-----+-----+-----+-----+ direction * of l2arc <== | buf | buf | buf | buf | buf | ===> of rebuild * fill +-----+-----+-----+-----+-----+ * ^ ^ * | | * | | * l2arc_feed_thread l2arc_rebuild * will place new bufs here restores bufs here * * During l2arc_rebuild() the device is not used by * l2arc_feed_thread() as dev->l2ad_rebuild is set to true. */ size += L2BLK_GET_LSIZE((&lb->lb_entries[i])->le_prop); asize += vdev_psize_to_asize(dev->l2ad_vdev, L2BLK_GET_PSIZE((&lb->lb_entries[i])->le_prop)); l2arc_hdr_restore(&lb->lb_entries[i], dev); } /* * Record rebuild stats: * size Logical size of restored buffers in the L2ARC * asize Aligned size of restored buffers in the L2ARC */ ARCSTAT_INCR(arcstat_l2_rebuild_size, size); ARCSTAT_INCR(arcstat_l2_rebuild_asize, asize); ARCSTAT_INCR(arcstat_l2_rebuild_bufs, log_entries); ARCSTAT_F_AVG(arcstat_l2_log_blk_avg_asize, lb_asize); ARCSTAT_F_AVG(arcstat_l2_data_to_meta_ratio, asize / lb_asize); ARCSTAT_BUMP(arcstat_l2_rebuild_log_blks); } /* * Restores a single ARC buf hdr from a log entry. The ARC buffer is put * into a state indicating that it has been evicted to L2ARC. */ static void l2arc_hdr_restore(const l2arc_log_ent_phys_t *le, l2arc_dev_t *dev) { arc_buf_hdr_t *hdr, *exists; kmutex_t *hash_lock; arc_buf_contents_t type = L2BLK_GET_TYPE((le)->le_prop); uint64_t asize; /* * Do all the allocation before grabbing any locks, this lets us * sleep if memory is full and we don't have to deal with failed * allocations. */ hdr = arc_buf_alloc_l2only(L2BLK_GET_LSIZE((le)->le_prop), type, dev, le->le_dva, le->le_daddr, L2BLK_GET_PSIZE((le)->le_prop), le->le_birth, L2BLK_GET_COMPRESS((le)->le_prop), le->le_complevel, L2BLK_GET_PROTECTED((le)->le_prop), L2BLK_GET_PREFETCH((le)->le_prop), L2BLK_GET_STATE((le)->le_prop)); asize = vdev_psize_to_asize(dev->l2ad_vdev, L2BLK_GET_PSIZE((le)->le_prop)); /* * vdev_space_update() has to be called before arc_hdr_destroy() to * avoid underflow since the latter also calls vdev_space_update(). */ l2arc_hdr_arcstats_increment(hdr); vdev_space_update(dev->l2ad_vdev, asize, 0, 0); mutex_enter(&dev->l2ad_mtx); list_insert_tail(&dev->l2ad_buflist, hdr); (void) zfs_refcount_add_many(&dev->l2ad_alloc, arc_hdr_size(hdr), hdr); mutex_exit(&dev->l2ad_mtx); exists = buf_hash_insert(hdr, &hash_lock); if (exists) { /* Buffer was already cached, no need to restore it. */ arc_hdr_destroy(hdr); /* * If the buffer is already cached, check whether it has * L2ARC metadata. If not, enter them and update the flag. * This is important is case of onlining a cache device, since * we previously evicted all L2ARC metadata from ARC. */ if (!HDR_HAS_L2HDR(exists)) { arc_hdr_set_flags(exists, ARC_FLAG_HAS_L2HDR); exists->b_l2hdr.b_dev = dev; exists->b_l2hdr.b_daddr = le->le_daddr; exists->b_l2hdr.b_arcs_state = L2BLK_GET_STATE((le)->le_prop); mutex_enter(&dev->l2ad_mtx); list_insert_tail(&dev->l2ad_buflist, exists); (void) zfs_refcount_add_many(&dev->l2ad_alloc, arc_hdr_size(exists), exists); mutex_exit(&dev->l2ad_mtx); l2arc_hdr_arcstats_increment(exists); vdev_space_update(dev->l2ad_vdev, asize, 0, 0); } ARCSTAT_BUMP(arcstat_l2_rebuild_bufs_precached); } mutex_exit(hash_lock); } /* * Starts an asynchronous read IO to read a log block. This is used in log * block reconstruction to start reading the next block before we are done * decoding and reconstructing the current block, to keep the l2arc device * nice and hot with read IO to process. * The returned zio will contain a newly allocated memory buffers for the IO * data which should then be freed by the caller once the zio is no longer * needed (i.e. due to it having completed). If you wish to abort this * zio, you should do so using l2arc_log_blk_fetch_abort, which takes * care of disposing of the allocated buffers correctly. */ static zio_t * l2arc_log_blk_fetch(vdev_t *vd, const l2arc_log_blkptr_t *lbp, l2arc_log_blk_phys_t *lb) { uint32_t asize; zio_t *pio; l2arc_read_callback_t *cb; /* L2BLK_GET_PSIZE returns aligned size for log blocks */ asize = L2BLK_GET_PSIZE((lbp)->lbp_prop); ASSERT(asize <= sizeof (l2arc_log_blk_phys_t)); cb = kmem_zalloc(sizeof (l2arc_read_callback_t), KM_SLEEP); cb->l2rcb_abd = abd_get_from_buf(lb, asize); pio = zio_root(vd->vdev_spa, l2arc_blk_fetch_done, cb, ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY); (void) zio_nowait(zio_read_phys(pio, vd, lbp->lbp_daddr, asize, cb->l2rcb_abd, ZIO_CHECKSUM_OFF, NULL, NULL, ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_DONT_CACHE | ZIO_FLAG_CANFAIL | ZIO_FLAG_DONT_PROPAGATE | ZIO_FLAG_DONT_RETRY, B_FALSE)); return (pio); } /* * Aborts a zio returned from l2arc_log_blk_fetch and frees the data * buffers allocated for it. */ static void l2arc_log_blk_fetch_abort(zio_t *zio) { (void) zio_wait(zio); } /* * Creates a zio to update the device header on an l2arc device. */ void l2arc_dev_hdr_update(l2arc_dev_t *dev) { l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr; const uint64_t l2dhdr_asize = dev->l2ad_dev_hdr_asize; abd_t *abd; int err; VERIFY(spa_config_held(dev->l2ad_spa, SCL_STATE_ALL, RW_READER)); l2dhdr->dh_magic = L2ARC_DEV_HDR_MAGIC; l2dhdr->dh_version = L2ARC_PERSISTENT_VERSION; l2dhdr->dh_spa_guid = spa_guid(dev->l2ad_vdev->vdev_spa); l2dhdr->dh_vdev_guid = dev->l2ad_vdev->vdev_guid; l2dhdr->dh_log_entries = dev->l2ad_log_entries; l2dhdr->dh_evict = dev->l2ad_evict; l2dhdr->dh_start = dev->l2ad_start; l2dhdr->dh_end = dev->l2ad_end; l2dhdr->dh_lb_asize = zfs_refcount_count(&dev->l2ad_lb_asize); l2dhdr->dh_lb_count = zfs_refcount_count(&dev->l2ad_lb_count); l2dhdr->dh_flags = 0; l2dhdr->dh_trim_action_time = dev->l2ad_vdev->vdev_trim_action_time; l2dhdr->dh_trim_state = dev->l2ad_vdev->vdev_trim_state; if (dev->l2ad_first) l2dhdr->dh_flags |= L2ARC_DEV_HDR_EVICT_FIRST; abd = abd_get_from_buf(l2dhdr, l2dhdr_asize); err = zio_wait(zio_write_phys(NULL, dev->l2ad_vdev, VDEV_LABEL_START_SIZE, l2dhdr_asize, abd, ZIO_CHECKSUM_LABEL, NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_CANFAIL, B_FALSE)); abd_free(abd); if (err != 0) { zfs_dbgmsg("L2ARC IO error (%d) while writing device header, " "vdev guid: %llu", err, (u_longlong_t)dev->l2ad_vdev->vdev_guid); } } /* * Commits a log block to the L2ARC device. This routine is invoked from * l2arc_write_buffers when the log block fills up. * This function allocates some memory to temporarily hold the serialized * buffer to be written. This is then released in l2arc_write_done. */ static void l2arc_log_blk_commit(l2arc_dev_t *dev, zio_t *pio, l2arc_write_callback_t *cb) { l2arc_log_blk_phys_t *lb = &dev->l2ad_log_blk; l2arc_dev_hdr_phys_t *l2dhdr = dev->l2ad_dev_hdr; uint64_t psize, asize; zio_t *wzio; l2arc_lb_abd_buf_t *abd_buf; uint8_t *tmpbuf; l2arc_lb_ptr_buf_t *lb_ptr_buf; VERIFY3S(dev->l2ad_log_ent_idx, ==, dev->l2ad_log_entries); tmpbuf = zio_buf_alloc(sizeof (*lb)); abd_buf = zio_buf_alloc(sizeof (*abd_buf)); abd_buf->abd = abd_get_from_buf(lb, sizeof (*lb)); lb_ptr_buf = kmem_zalloc(sizeof (l2arc_lb_ptr_buf_t), KM_SLEEP); lb_ptr_buf->lb_ptr = kmem_zalloc(sizeof (l2arc_log_blkptr_t), KM_SLEEP); /* link the buffer into the block chain */ lb->lb_prev_lbp = l2dhdr->dh_start_lbps[1]; lb->lb_magic = L2ARC_LOG_BLK_MAGIC; /* * l2arc_log_blk_commit() may be called multiple times during a single * l2arc_write_buffers() call. Save the allocated abd buffers in a list * so we can free them in l2arc_write_done() later on. */ list_insert_tail(&cb->l2wcb_abd_list, abd_buf); /* try to compress the buffer */ psize = zio_compress_data(ZIO_COMPRESS_LZ4, abd_buf->abd, tmpbuf, sizeof (*lb), 0); /* a log block is never entirely zero */ ASSERT(psize != 0); asize = vdev_psize_to_asize(dev->l2ad_vdev, psize); ASSERT(asize <= sizeof (*lb)); /* * Update the start log block pointer in the device header to point * to the log block we're about to write. */ l2dhdr->dh_start_lbps[1] = l2dhdr->dh_start_lbps[0]; l2dhdr->dh_start_lbps[0].lbp_daddr = dev->l2ad_hand; l2dhdr->dh_start_lbps[0].lbp_payload_asize = dev->l2ad_log_blk_payload_asize; l2dhdr->dh_start_lbps[0].lbp_payload_start = dev->l2ad_log_blk_payload_start; L2BLK_SET_LSIZE( (&l2dhdr->dh_start_lbps[0])->lbp_prop, sizeof (*lb)); L2BLK_SET_PSIZE( (&l2dhdr->dh_start_lbps[0])->lbp_prop, asize); L2BLK_SET_CHECKSUM( (&l2dhdr->dh_start_lbps[0])->lbp_prop, ZIO_CHECKSUM_FLETCHER_4); if (asize < sizeof (*lb)) { /* compression succeeded */ memset(tmpbuf + psize, 0, asize - psize); L2BLK_SET_COMPRESS( (&l2dhdr->dh_start_lbps[0])->lbp_prop, ZIO_COMPRESS_LZ4); } else { /* compression failed */ memcpy(tmpbuf, lb, sizeof (*lb)); L2BLK_SET_COMPRESS( (&l2dhdr->dh_start_lbps[0])->lbp_prop, ZIO_COMPRESS_OFF); } /* checksum what we're about to write */ fletcher_4_native(tmpbuf, asize, NULL, &l2dhdr->dh_start_lbps[0].lbp_cksum); abd_free(abd_buf->abd); /* perform the write itself */ abd_buf->abd = abd_get_from_buf(tmpbuf, sizeof (*lb)); abd_take_ownership_of_buf(abd_buf->abd, B_TRUE); wzio = zio_write_phys(pio, dev->l2ad_vdev, dev->l2ad_hand, asize, abd_buf->abd, ZIO_CHECKSUM_OFF, NULL, NULL, ZIO_PRIORITY_ASYNC_WRITE, ZIO_FLAG_CANFAIL, B_FALSE); DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, zio_t *, wzio); (void) zio_nowait(wzio); dev->l2ad_hand += asize; /* * Include the committed log block's pointer in the list of pointers * to log blocks present in the L2ARC device. */ memcpy(lb_ptr_buf->lb_ptr, &l2dhdr->dh_start_lbps[0], sizeof (l2arc_log_blkptr_t)); mutex_enter(&dev->l2ad_mtx); list_insert_head(&dev->l2ad_lbptr_list, lb_ptr_buf); ARCSTAT_INCR(arcstat_l2_log_blk_asize, asize); ARCSTAT_BUMP(arcstat_l2_log_blk_count); zfs_refcount_add_many(&dev->l2ad_lb_asize, asize, lb_ptr_buf); zfs_refcount_add(&dev->l2ad_lb_count, lb_ptr_buf); mutex_exit(&dev->l2ad_mtx); vdev_space_update(dev->l2ad_vdev, asize, 0, 0); /* bump the kstats */ ARCSTAT_INCR(arcstat_l2_write_bytes, asize); ARCSTAT_BUMP(arcstat_l2_log_blk_writes); ARCSTAT_F_AVG(arcstat_l2_log_blk_avg_asize, asize); ARCSTAT_F_AVG(arcstat_l2_data_to_meta_ratio, dev->l2ad_log_blk_payload_asize / asize); /* start a new log block */ dev->l2ad_log_ent_idx = 0; dev->l2ad_log_blk_payload_asize = 0; dev->l2ad_log_blk_payload_start = 0; } /* * Validates an L2ARC log block address to make sure that it can be read * from the provided L2ARC device. */ boolean_t l2arc_log_blkptr_valid(l2arc_dev_t *dev, const l2arc_log_blkptr_t *lbp) { /* L2BLK_GET_PSIZE returns aligned size for log blocks */ uint64_t asize = L2BLK_GET_PSIZE((lbp)->lbp_prop); uint64_t end = lbp->lbp_daddr + asize - 1; uint64_t start = lbp->lbp_payload_start; boolean_t evicted = B_FALSE; /* * A log block is valid if all of the following conditions are true: * - it fits entirely (including its payload) between l2ad_start and * l2ad_end * - it has a valid size * - neither the log block itself nor part of its payload was evicted * by l2arc_evict(): * * l2ad_hand l2ad_evict * | | lbp_daddr * | start | | end * | | | | | * V V V V V * l2ad_start ============================================ l2ad_end * --------------------------|||| * ^ ^ * | log block * payload */ evicted = l2arc_range_check_overlap(start, end, dev->l2ad_hand) || l2arc_range_check_overlap(start, end, dev->l2ad_evict) || l2arc_range_check_overlap(dev->l2ad_hand, dev->l2ad_evict, start) || l2arc_range_check_overlap(dev->l2ad_hand, dev->l2ad_evict, end); return (start >= dev->l2ad_start && end <= dev->l2ad_end && asize > 0 && asize <= sizeof (l2arc_log_blk_phys_t) && (!evicted || dev->l2ad_first)); } /* * Inserts ARC buffer header `hdr' into the current L2ARC log block on * the device. The buffer being inserted must be present in L2ARC. * Returns B_TRUE if the L2ARC log block is full and needs to be committed * to L2ARC, or B_FALSE if it still has room for more ARC buffers. */ static boolean_t l2arc_log_blk_insert(l2arc_dev_t *dev, const arc_buf_hdr_t *hdr) { l2arc_log_blk_phys_t *lb = &dev->l2ad_log_blk; l2arc_log_ent_phys_t *le; if (dev->l2ad_log_entries == 0) return (B_FALSE); int index = dev->l2ad_log_ent_idx++; ASSERT3S(index, <, dev->l2ad_log_entries); ASSERT(HDR_HAS_L2HDR(hdr)); le = &lb->lb_entries[index]; memset(le, 0, sizeof (*le)); le->le_dva = hdr->b_dva; le->le_birth = hdr->b_birth; le->le_daddr = hdr->b_l2hdr.b_daddr; if (index == 0) dev->l2ad_log_blk_payload_start = le->le_daddr; L2BLK_SET_LSIZE((le)->le_prop, HDR_GET_LSIZE(hdr)); L2BLK_SET_PSIZE((le)->le_prop, HDR_GET_PSIZE(hdr)); L2BLK_SET_COMPRESS((le)->le_prop, HDR_GET_COMPRESS(hdr)); le->le_complevel = hdr->b_complevel; L2BLK_SET_TYPE((le)->le_prop, hdr->b_type); L2BLK_SET_PROTECTED((le)->le_prop, !!(HDR_PROTECTED(hdr))); L2BLK_SET_PREFETCH((le)->le_prop, !!(HDR_PREFETCH(hdr))); L2BLK_SET_STATE((le)->le_prop, hdr->b_l1hdr.b_state->arcs_state); dev->l2ad_log_blk_payload_asize += vdev_psize_to_asize(dev->l2ad_vdev, HDR_GET_PSIZE(hdr)); return (dev->l2ad_log_ent_idx == dev->l2ad_log_entries); } /* * Checks whether a given L2ARC device address sits in a time-sequential * range. The trick here is that the L2ARC is a rotary buffer, so we can't * just do a range comparison, we need to handle the situation in which the * range wraps around the end of the L2ARC device. Arguments: * bottom -- Lower end of the range to check (written to earlier). * top -- Upper end of the range to check (written to later). * check -- The address for which we want to determine if it sits in * between the top and bottom. * * The 3-way conditional below represents the following cases: * * bottom < top : Sequentially ordered case: * --------+-------------------+ * | (overlap here?) | * L2ARC dev V V * |---------------============--------------| * * bottom > top: Looped-around case: * --------+------------------+ * | (overlap here?) | * L2ARC dev V V * |===============---------------===========| * ^ ^ * | (or here?) | * +---------------+--------- * * top == bottom : Just a single address comparison. */ boolean_t l2arc_range_check_overlap(uint64_t bottom, uint64_t top, uint64_t check) { if (bottom < top) return (bottom <= check && check <= top); else if (bottom > top) return (check <= top || bottom <= check); else return (check == top); } EXPORT_SYMBOL(arc_buf_size); EXPORT_SYMBOL(arc_write); EXPORT_SYMBOL(arc_read); EXPORT_SYMBOL(arc_buf_info); EXPORT_SYMBOL(arc_getbuf_func); EXPORT_SYMBOL(arc_add_prune_callback); EXPORT_SYMBOL(arc_remove_prune_callback); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, min, param_set_arc_min, param_get_long, ZMOD_RW, "Minimum ARC size in bytes"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, max, param_set_arc_max, param_get_long, ZMOD_RW, "Maximum ARC size in bytes"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, meta_limit, param_set_arc_long, param_get_long, ZMOD_RW, "Metadata limit for ARC size in bytes"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, meta_limit_percent, param_set_arc_long, param_get_long, ZMOD_RW, "Percent of ARC size for ARC meta limit"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, meta_min, param_set_arc_long, param_get_long, ZMOD_RW, "Minimum ARC metadata size in bytes"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, meta_prune, INT, ZMOD_RW, "Meta objects to scan for prune"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, meta_adjust_restarts, INT, ZMOD_RW, "Limit number of restarts in arc_evict_meta"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, meta_strategy, INT, ZMOD_RW, "Meta reclaim strategy"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, grow_retry, param_set_arc_int, param_get_int, ZMOD_RW, "Seconds before growing ARC size"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, p_dampener_disable, INT, ZMOD_RW, "Disable arc_p adapt dampener"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, shrink_shift, param_set_arc_int, param_get_int, ZMOD_RW, "log2(fraction of ARC to reclaim)"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, pc_percent, UINT, ZMOD_RW, "Percent of pagecache to reclaim ARC to"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, p_min_shift, param_set_arc_int, param_get_int, ZMOD_RW, "arc_c shift to calc min/max arc_p"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, average_blocksize, INT, ZMOD_RD, "Target average block size"); ZFS_MODULE_PARAM(zfs, zfs_, compressed_arc_enabled, INT, ZMOD_RW, "Disable compressed ARC buffers"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, min_prefetch_ms, param_set_arc_int, param_get_int, ZMOD_RW, "Min life of prefetch block in ms"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, min_prescient_prefetch_ms, param_set_arc_int, param_get_int, ZMOD_RW, "Min life of prescient prefetched block in ms"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, write_max, ULONG, ZMOD_RW, "Max write bytes per interval"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, write_boost, ULONG, ZMOD_RW, "Extra write bytes during device warmup"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, headroom, ULONG, ZMOD_RW, "Number of max device writes to precache"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, headroom_boost, ULONG, ZMOD_RW, "Compressed l2arc_headroom multiplier"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, trim_ahead, ULONG, ZMOD_RW, "TRIM ahead L2ARC write size multiplier"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, feed_secs, ULONG, ZMOD_RW, "Seconds between L2ARC writing"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, feed_min_ms, ULONG, ZMOD_RW, "Min feed interval in milliseconds"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, noprefetch, INT, ZMOD_RW, "Skip caching prefetched buffers"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, feed_again, INT, ZMOD_RW, "Turbo L2ARC warmup"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, norw, INT, ZMOD_RW, "No reads during writes"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, meta_percent, INT, ZMOD_RW, "Percent of ARC size allowed for L2ARC-only headers"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, rebuild_enabled, INT, ZMOD_RW, "Rebuild the L2ARC when importing a pool"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, rebuild_blocks_min_l2size, ULONG, ZMOD_RW, "Min size in bytes to write rebuild log blocks in L2ARC"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, mfuonly, INT, ZMOD_RW, "Cache only MFU data from ARC into L2ARC"); ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, exclude_special, INT, ZMOD_RW, "Exclude dbufs on special vdevs from being cached to L2ARC if set."); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, lotsfree_percent, param_set_arc_int, param_get_int, ZMOD_RW, "System free memory I/O throttle in bytes"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, sys_free, param_set_arc_long, param_get_long, ZMOD_RW, "System free memory target size in bytes"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, dnode_limit, param_set_arc_long, param_get_long, ZMOD_RW, "Minimum bytes of dnodes in ARC"); ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, dnode_limit_percent, param_set_arc_long, param_get_long, ZMOD_RW, "Percent of ARC meta buffers for dnodes"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, dnode_reduce_percent, ULONG, ZMOD_RW, "Percentage of excess dnodes to try to unpin"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, eviction_pct, INT, ZMOD_RW, "When full, ARC allocation waits for eviction of this % of alloc size"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, evict_batch_limit, INT, ZMOD_RW, "The number of headers to evict per sublist before moving to the next"); ZFS_MODULE_PARAM(zfs_arc, zfs_arc_, prune_task_threads, INT, ZMOD_RW, "Number of arc_prune threads"); diff --git a/module/zfs/dnode.c b/module/zfs/dnode.c index 67fe1e2c9a0f..ef27dfd40af1 100644 --- a/module/zfs/dnode.c +++ b/module/zfs/dnode.c @@ -1,2579 +1,2579 @@ /* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or https://opensource.org/licenses/CDDL-1.0. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2012, 2020 by Delphix. All rights reserved. * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include dnode_stats_t dnode_stats = { { "dnode_hold_dbuf_hold", KSTAT_DATA_UINT64 }, { "dnode_hold_dbuf_read", KSTAT_DATA_UINT64 }, { "dnode_hold_alloc_hits", KSTAT_DATA_UINT64 }, { "dnode_hold_alloc_misses", KSTAT_DATA_UINT64 }, { "dnode_hold_alloc_interior", KSTAT_DATA_UINT64 }, { "dnode_hold_alloc_lock_retry", KSTAT_DATA_UINT64 }, { "dnode_hold_alloc_lock_misses", KSTAT_DATA_UINT64 }, { "dnode_hold_alloc_type_none", KSTAT_DATA_UINT64 }, { "dnode_hold_free_hits", KSTAT_DATA_UINT64 }, { "dnode_hold_free_misses", KSTAT_DATA_UINT64 }, { "dnode_hold_free_lock_misses", KSTAT_DATA_UINT64 }, { "dnode_hold_free_lock_retry", KSTAT_DATA_UINT64 }, { "dnode_hold_free_overflow", KSTAT_DATA_UINT64 }, { "dnode_hold_free_refcount", KSTAT_DATA_UINT64 }, { "dnode_free_interior_lock_retry", KSTAT_DATA_UINT64 }, { "dnode_allocate", KSTAT_DATA_UINT64 }, { "dnode_reallocate", KSTAT_DATA_UINT64 }, { "dnode_buf_evict", KSTAT_DATA_UINT64 }, { "dnode_alloc_next_chunk", KSTAT_DATA_UINT64 }, { "dnode_alloc_race", KSTAT_DATA_UINT64 }, { "dnode_alloc_next_block", KSTAT_DATA_UINT64 }, { "dnode_move_invalid", KSTAT_DATA_UINT64 }, { "dnode_move_recheck1", KSTAT_DATA_UINT64 }, { "dnode_move_recheck2", KSTAT_DATA_UINT64 }, { "dnode_move_special", KSTAT_DATA_UINT64 }, { "dnode_move_handle", KSTAT_DATA_UINT64 }, { "dnode_move_rwlock", KSTAT_DATA_UINT64 }, { "dnode_move_active", KSTAT_DATA_UINT64 }, }; static kstat_t *dnode_ksp; static kmem_cache_t *dnode_cache; static dnode_phys_t dnode_phys_zero __maybe_unused; int zfs_default_bs = SPA_MINBLOCKSHIFT; int zfs_default_ibs = DN_MAX_INDBLKSHIFT; #ifdef _KERNEL static kmem_cbrc_t dnode_move(void *, void *, size_t, void *); #endif /* _KERNEL */ static int dbuf_compare(const void *x1, const void *x2) { const dmu_buf_impl_t *d1 = x1; const dmu_buf_impl_t *d2 = x2; int cmp = TREE_CMP(d1->db_level, d2->db_level); if (likely(cmp)) return (cmp); cmp = TREE_CMP(d1->db_blkid, d2->db_blkid); if (likely(cmp)) return (cmp); if (d1->db_state == DB_SEARCH) { ASSERT3S(d2->db_state, !=, DB_SEARCH); return (-1); } else if (d2->db_state == DB_SEARCH) { ASSERT3S(d1->db_state, !=, DB_SEARCH); return (1); } return (TREE_PCMP(d1, d2)); } static int dnode_cons(void *arg, void *unused, int kmflag) { (void) unused, (void) kmflag; dnode_t *dn = arg; rw_init(&dn->dn_struct_rwlock, NULL, RW_NOLOCKDEP, NULL); mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL); mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL); cv_init(&dn->dn_notxholds, NULL, CV_DEFAULT, NULL); cv_init(&dn->dn_nodnholds, NULL, CV_DEFAULT, NULL); /* * Every dbuf has a reference, and dropping a tracked reference is * O(number of references), so don't track dn_holds. */ zfs_refcount_create_untracked(&dn->dn_holds); zfs_refcount_create(&dn->dn_tx_holds); list_link_init(&dn->dn_link); memset(dn->dn_next_type, 0, sizeof (dn->dn_next_type)); memset(dn->dn_next_nblkptr, 0, sizeof (dn->dn_next_nblkptr)); memset(dn->dn_next_nlevels, 0, sizeof (dn->dn_next_nlevels)); memset(dn->dn_next_indblkshift, 0, sizeof (dn->dn_next_indblkshift)); memset(dn->dn_next_bonustype, 0, sizeof (dn->dn_next_bonustype)); memset(dn->dn_rm_spillblk, 0, sizeof (dn->dn_rm_spillblk)); memset(dn->dn_next_bonuslen, 0, sizeof (dn->dn_next_bonuslen)); memset(dn->dn_next_blksz, 0, sizeof (dn->dn_next_blksz)); memset(dn->dn_next_maxblkid, 0, sizeof (dn->dn_next_maxblkid)); for (int i = 0; i < TXG_SIZE; i++) { multilist_link_init(&dn->dn_dirty_link[i]); dn->dn_free_ranges[i] = NULL; list_create(&dn->dn_dirty_records[i], sizeof (dbuf_dirty_record_t), offsetof(dbuf_dirty_record_t, dr_dirty_node)); } dn->dn_allocated_txg = 0; dn->dn_free_txg = 0; dn->dn_assigned_txg = 0; dn->dn_dirty_txg = 0; dn->dn_dirtyctx = 0; dn->dn_dirtyctx_firstset = NULL; dn->dn_bonus = NULL; dn->dn_have_spill = B_FALSE; dn->dn_zio = NULL; dn->dn_oldused = 0; dn->dn_oldflags = 0; dn->dn_olduid = 0; dn->dn_oldgid = 0; dn->dn_oldprojid = ZFS_DEFAULT_PROJID; dn->dn_newuid = 0; dn->dn_newgid = 0; dn->dn_newprojid = ZFS_DEFAULT_PROJID; dn->dn_id_flags = 0; dn->dn_dbufs_count = 0; avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), offsetof(dmu_buf_impl_t, db_link)); dn->dn_moved = 0; return (0); } static void dnode_dest(void *arg, void *unused) { (void) unused; dnode_t *dn = arg; rw_destroy(&dn->dn_struct_rwlock); mutex_destroy(&dn->dn_mtx); mutex_destroy(&dn->dn_dbufs_mtx); cv_destroy(&dn->dn_notxholds); cv_destroy(&dn->dn_nodnholds); zfs_refcount_destroy(&dn->dn_holds); zfs_refcount_destroy(&dn->dn_tx_holds); ASSERT(!list_link_active(&dn->dn_link)); for (int i = 0; i < TXG_SIZE; i++) { ASSERT(!multilist_link_active(&dn->dn_dirty_link[i])); ASSERT3P(dn->dn_free_ranges[i], ==, NULL); list_destroy(&dn->dn_dirty_records[i]); ASSERT0(dn->dn_next_nblkptr[i]); ASSERT0(dn->dn_next_nlevels[i]); ASSERT0(dn->dn_next_indblkshift[i]); ASSERT0(dn->dn_next_bonustype[i]); ASSERT0(dn->dn_rm_spillblk[i]); ASSERT0(dn->dn_next_bonuslen[i]); ASSERT0(dn->dn_next_blksz[i]); ASSERT0(dn->dn_next_maxblkid[i]); } ASSERT0(dn->dn_allocated_txg); ASSERT0(dn->dn_free_txg); ASSERT0(dn->dn_assigned_txg); ASSERT0(dn->dn_dirty_txg); ASSERT0(dn->dn_dirtyctx); ASSERT3P(dn->dn_dirtyctx_firstset, ==, NULL); ASSERT3P(dn->dn_bonus, ==, NULL); ASSERT(!dn->dn_have_spill); ASSERT3P(dn->dn_zio, ==, NULL); ASSERT0(dn->dn_oldused); ASSERT0(dn->dn_oldflags); ASSERT0(dn->dn_olduid); ASSERT0(dn->dn_oldgid); ASSERT0(dn->dn_oldprojid); ASSERT0(dn->dn_newuid); ASSERT0(dn->dn_newgid); ASSERT0(dn->dn_newprojid); ASSERT0(dn->dn_id_flags); ASSERT0(dn->dn_dbufs_count); avl_destroy(&dn->dn_dbufs); } void dnode_init(void) { ASSERT(dnode_cache == NULL); dnode_cache = kmem_cache_create("dnode_t", sizeof (dnode_t), 0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0); kmem_cache_set_move(dnode_cache, dnode_move); dnode_ksp = kstat_create("zfs", 0, "dnodestats", "misc", KSTAT_TYPE_NAMED, sizeof (dnode_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); if (dnode_ksp != NULL) { dnode_ksp->ks_data = &dnode_stats; kstat_install(dnode_ksp); } } void dnode_fini(void) { if (dnode_ksp != NULL) { kstat_delete(dnode_ksp); dnode_ksp = NULL; } kmem_cache_destroy(dnode_cache); dnode_cache = NULL; } #ifdef ZFS_DEBUG void dnode_verify(dnode_t *dn) { int drop_struct_lock = FALSE; ASSERT(dn->dn_phys); ASSERT(dn->dn_objset); ASSERT(dn->dn_handle->dnh_dnode == dn); ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY)) return; if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) { rw_enter(&dn->dn_struct_rwlock, RW_READER); drop_struct_lock = TRUE; } if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) { int i; int max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots); ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT); if (dn->dn_datablkshift) { ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT); ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT); ASSERT3U(1<dn_datablkshift, ==, dn->dn_datablksz); } ASSERT3U(dn->dn_nlevels, <=, 30); ASSERT(DMU_OT_IS_VALID(dn->dn_type)); ASSERT3U(dn->dn_nblkptr, >=, 1); ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); ASSERT3U(dn->dn_bonuslen, <=, max_bonuslen); ASSERT3U(dn->dn_datablksz, ==, dn->dn_datablkszsec << SPA_MINBLOCKSHIFT); ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0); ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) + dn->dn_bonuslen, <=, max_bonuslen); for (i = 0; i < TXG_SIZE; i++) { ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels); } } if (dn->dn_phys->dn_type != DMU_OT_NONE) ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels); ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL); if (dn->dn_dbuf != NULL) { ASSERT3P(dn->dn_phys, ==, (dnode_phys_t *)dn->dn_dbuf->db.db_data + (dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT))); } if (drop_struct_lock) rw_exit(&dn->dn_struct_rwlock); } #endif void dnode_byteswap(dnode_phys_t *dnp) { uint64_t *buf64 = (void*)&dnp->dn_blkptr; int i; if (dnp->dn_type == DMU_OT_NONE) { memset(dnp, 0, sizeof (dnode_phys_t)); return; } dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec); dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen); dnp->dn_extra_slots = BSWAP_8(dnp->dn_extra_slots); dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid); dnp->dn_used = BSWAP_64(dnp->dn_used); /* * dn_nblkptr is only one byte, so it's OK to read it in either * byte order. We can't read dn_bouslen. */ ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT); ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR); for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++) buf64[i] = BSWAP_64(buf64[i]); /* * OK to check dn_bonuslen for zero, because it won't matter if * we have the wrong byte order. This is necessary because the * dnode dnode is smaller than a regular dnode. */ if (dnp->dn_bonuslen != 0) { dmu_object_byteswap_t byteswap; ASSERT(DMU_OT_IS_VALID(dnp->dn_bonustype)); byteswap = DMU_OT_BYTESWAP(dnp->dn_bonustype); dmu_ot_byteswap[byteswap].ob_func(DN_BONUS(dnp), DN_MAX_BONUS_LEN(dnp)); } /* Swap SPILL block if we have one */ if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) byteswap_uint64_array(DN_SPILL_BLKPTR(dnp), sizeof (blkptr_t)); } void dnode_buf_byteswap(void *vbuf, size_t size) { int i = 0; ASSERT3U(sizeof (dnode_phys_t), ==, (1<dn_type != DMU_OT_NONE) i += dnp->dn_extra_slots * DNODE_MIN_SIZE; } } void dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx) { ASSERT3U(zfs_refcount_count(&dn->dn_holds), >=, 1); dnode_setdirty(dn, tx); rw_enter(&dn->dn_struct_rwlock, RW_WRITER); ASSERT3U(newsize, <=, DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) - (dn->dn_nblkptr-1) * sizeof (blkptr_t)); if (newsize < dn->dn_bonuslen) { /* clear any data after the end of the new size */ size_t diff = dn->dn_bonuslen - newsize; char *data_end = ((char *)dn->dn_bonus->db.db_data) + newsize; memset(data_end, 0, diff); } dn->dn_bonuslen = newsize; if (newsize == 0) dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN; else dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; rw_exit(&dn->dn_struct_rwlock); } void dnode_setbonus_type(dnode_t *dn, dmu_object_type_t newtype, dmu_tx_t *tx) { ASSERT3U(zfs_refcount_count(&dn->dn_holds), >=, 1); dnode_setdirty(dn, tx); rw_enter(&dn->dn_struct_rwlock, RW_WRITER); dn->dn_bonustype = newtype; dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; rw_exit(&dn->dn_struct_rwlock); } void dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx) { ASSERT3U(zfs_refcount_count(&dn->dn_holds), >=, 1); ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); dnode_setdirty(dn, tx); dn->dn_rm_spillblk[tx->tx_txg & TXG_MASK] = DN_KILL_SPILLBLK; dn->dn_have_spill = B_FALSE; } static void dnode_setdblksz(dnode_t *dn, int size) { ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE)); ASSERT3U(size, <=, SPA_MAXBLOCKSIZE); ASSERT3U(size, >=, SPA_MINBLOCKSIZE); ASSERT3U(size >> SPA_MINBLOCKSHIFT, <, 1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8)); dn->dn_datablksz = size; dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT; dn->dn_datablkshift = ISP2(size) ? highbit64(size - 1) : 0; } static dnode_t * dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db, uint64_t object, dnode_handle_t *dnh) { dnode_t *dn; dn = kmem_cache_alloc(dnode_cache, KM_SLEEP); dn->dn_moved = 0; /* * Defer setting dn_objset until the dnode is ready to be a candidate * for the dnode_move() callback. */ dn->dn_object = object; dn->dn_dbuf = db; dn->dn_handle = dnh; dn->dn_phys = dnp; if (dnp->dn_datablkszsec) { dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT); } else { dn->dn_datablksz = 0; dn->dn_datablkszsec = 0; dn->dn_datablkshift = 0; } dn->dn_indblkshift = dnp->dn_indblkshift; dn->dn_nlevels = dnp->dn_nlevels; dn->dn_type = dnp->dn_type; dn->dn_nblkptr = dnp->dn_nblkptr; dn->dn_checksum = dnp->dn_checksum; dn->dn_compress = dnp->dn_compress; dn->dn_bonustype = dnp->dn_bonustype; dn->dn_bonuslen = dnp->dn_bonuslen; dn->dn_num_slots = dnp->dn_extra_slots + 1; dn->dn_maxblkid = dnp->dn_maxblkid; dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0); dn->dn_id_flags = 0; dmu_zfetch_init(&dn->dn_zfetch, dn); ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type)); ASSERT(zrl_is_locked(&dnh->dnh_zrlock)); ASSERT(!DN_SLOT_IS_PTR(dnh->dnh_dnode)); mutex_enter(&os->os_lock); /* * Exclude special dnodes from os_dnodes so an empty os_dnodes * signifies that the special dnodes have no references from * their children (the entries in os_dnodes). This allows * dnode_destroy() to easily determine if the last child has * been removed and then complete eviction of the objset. */ if (!DMU_OBJECT_IS_SPECIAL(object)) list_insert_head(&os->os_dnodes, dn); membar_producer(); /* * Everything else must be valid before assigning dn_objset * makes the dnode eligible for dnode_move(). */ dn->dn_objset = os; dnh->dnh_dnode = dn; mutex_exit(&os->os_lock); arc_space_consume(sizeof (dnode_t), ARC_SPACE_DNODE); return (dn); } /* * Caller must be holding the dnode handle, which is released upon return. */ static void dnode_destroy(dnode_t *dn) { objset_t *os = dn->dn_objset; boolean_t complete_os_eviction = B_FALSE; ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0); mutex_enter(&os->os_lock); POINTER_INVALIDATE(&dn->dn_objset); if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { list_remove(&os->os_dnodes, dn); complete_os_eviction = list_is_empty(&os->os_dnodes) && list_link_active(&os->os_evicting_node); } mutex_exit(&os->os_lock); /* the dnode can no longer move, so we can release the handle */ if (!zrl_is_locked(&dn->dn_handle->dnh_zrlock)) zrl_remove(&dn->dn_handle->dnh_zrlock); dn->dn_allocated_txg = 0; dn->dn_free_txg = 0; dn->dn_assigned_txg = 0; dn->dn_dirty_txg = 0; dn->dn_dirtyctx = 0; dn->dn_dirtyctx_firstset = NULL; if (dn->dn_bonus != NULL) { mutex_enter(&dn->dn_bonus->db_mtx); dbuf_destroy(dn->dn_bonus); dn->dn_bonus = NULL; } dn->dn_zio = NULL; dn->dn_have_spill = B_FALSE; dn->dn_oldused = 0; dn->dn_oldflags = 0; dn->dn_olduid = 0; dn->dn_oldgid = 0; dn->dn_oldprojid = ZFS_DEFAULT_PROJID; dn->dn_newuid = 0; dn->dn_newgid = 0; dn->dn_newprojid = ZFS_DEFAULT_PROJID; dn->dn_id_flags = 0; dmu_zfetch_fini(&dn->dn_zfetch); kmem_cache_free(dnode_cache, dn); arc_space_return(sizeof (dnode_t), ARC_SPACE_DNODE); if (complete_os_eviction) dmu_objset_evict_done(os); } void dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs, dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx) { int i; ASSERT3U(dn_slots, >, 0); ASSERT3U(dn_slots << DNODE_SHIFT, <=, spa_maxdnodesize(dmu_objset_spa(dn->dn_objset))); ASSERT3U(blocksize, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); if (blocksize == 0) blocksize = 1 << zfs_default_bs; else blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE); if (ibs == 0) ibs = zfs_default_ibs; ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT); dprintf("os=%p obj=%llu txg=%llu blocksize=%d ibs=%d dn_slots=%d\n", dn->dn_objset, (u_longlong_t)dn->dn_object, (u_longlong_t)tx->tx_txg, blocksize, ibs, dn_slots); DNODE_STAT_BUMP(dnode_allocate); ASSERT(dn->dn_type == DMU_OT_NONE); ASSERT0(memcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t))); ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE); ASSERT(ot != DMU_OT_NONE); ASSERT(DMU_OT_IS_VALID(ot)); ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || (bonustype == DMU_OT_SA && bonuslen == 0) || (bonustype != DMU_OT_NONE && bonuslen != 0)); ASSERT(DMU_OT_IS_VALID(bonustype)); ASSERT3U(bonuslen, <=, DN_SLOTS_TO_BONUSLEN(dn_slots)); ASSERT(dn->dn_type == DMU_OT_NONE); ASSERT0(dn->dn_maxblkid); ASSERT0(dn->dn_allocated_txg); ASSERT0(dn->dn_assigned_txg); ASSERT(zfs_refcount_is_zero(&dn->dn_tx_holds)); ASSERT3U(zfs_refcount_count(&dn->dn_holds), <=, 1); ASSERT(avl_is_empty(&dn->dn_dbufs)); for (i = 0; i < TXG_SIZE; i++) { ASSERT0(dn->dn_next_nblkptr[i]); ASSERT0(dn->dn_next_nlevels[i]); ASSERT0(dn->dn_next_indblkshift[i]); ASSERT0(dn->dn_next_bonuslen[i]); ASSERT0(dn->dn_next_bonustype[i]); ASSERT0(dn->dn_rm_spillblk[i]); ASSERT0(dn->dn_next_blksz[i]); ASSERT0(dn->dn_next_maxblkid[i]); ASSERT(!multilist_link_active(&dn->dn_dirty_link[i])); ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL); ASSERT3P(dn->dn_free_ranges[i], ==, NULL); } dn->dn_type = ot; dnode_setdblksz(dn, blocksize); dn->dn_indblkshift = ibs; dn->dn_nlevels = 1; dn->dn_num_slots = dn_slots; if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ dn->dn_nblkptr = 1; else { dn->dn_nblkptr = MIN(DN_MAX_NBLKPTR, 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >> SPA_BLKPTRSHIFT)); } dn->dn_bonustype = bonustype; dn->dn_bonuslen = bonuslen; dn->dn_checksum = ZIO_CHECKSUM_INHERIT; dn->dn_compress = ZIO_COMPRESS_INHERIT; dn->dn_dirtyctx = 0; dn->dn_free_txg = 0; dn->dn_dirtyctx_firstset = NULL; dn->dn_dirty_txg = 0; dn->dn_allocated_txg = tx->tx_txg; dn->dn_id_flags = 0; dnode_setdirty(dn, tx); dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs; dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen; dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype; dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz; } void dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, dmu_object_type_t bonustype, int bonuslen, int dn_slots, boolean_t keep_spill, dmu_tx_t *tx) { int nblkptr; ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE); ASSERT3U(blocksize, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); ASSERT0(blocksize % SPA_MINBLOCKSIZE); ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx)); ASSERT(tx->tx_txg != 0); ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) || (bonustype != DMU_OT_NONE && bonuslen != 0) || (bonustype == DMU_OT_SA && bonuslen == 0)); ASSERT(DMU_OT_IS_VALID(bonustype)); ASSERT3U(bonuslen, <=, DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(dn->dn_objset)))); ASSERT3U(bonuslen, <=, DN_BONUS_SIZE(dn_slots << DNODE_SHIFT)); dnode_free_interior_slots(dn); DNODE_STAT_BUMP(dnode_reallocate); /* clean up any unreferenced dbufs */ dnode_evict_dbufs(dn); dn->dn_id_flags = 0; rw_enter(&dn->dn_struct_rwlock, RW_WRITER); dnode_setdirty(dn, tx); if (dn->dn_datablksz != blocksize) { /* change blocksize */ ASSERT0(dn->dn_maxblkid); ASSERT(BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) || dnode_block_freed(dn, 0)); dnode_setdblksz(dn, blocksize); dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = blocksize; } if (dn->dn_bonuslen != bonuslen) dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = bonuslen; if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */ nblkptr = 1; else nblkptr = MIN(DN_MAX_NBLKPTR, 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >> SPA_BLKPTRSHIFT)); if (dn->dn_bonustype != bonustype) dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = bonustype; if (dn->dn_nblkptr != nblkptr) dn->dn_next_nblkptr[tx->tx_txg & TXG_MASK] = nblkptr; if (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR && !keep_spill) { dbuf_rm_spill(dn, tx); dnode_rm_spill(dn, tx); } rw_exit(&dn->dn_struct_rwlock); /* change type */ dn->dn_type = ot; /* change bonus size and type */ mutex_enter(&dn->dn_mtx); dn->dn_bonustype = bonustype; dn->dn_bonuslen = bonuslen; dn->dn_num_slots = dn_slots; dn->dn_nblkptr = nblkptr; dn->dn_checksum = ZIO_CHECKSUM_INHERIT; dn->dn_compress = ZIO_COMPRESS_INHERIT; ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR); /* fix up the bonus db_size */ if (dn->dn_bonus) { dn->dn_bonus->db.db_size = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) - (dn->dn_nblkptr-1) * sizeof (blkptr_t); ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size); } dn->dn_allocated_txg = tx->tx_txg; mutex_exit(&dn->dn_mtx); } #ifdef _KERNEL static void dnode_move_impl(dnode_t *odn, dnode_t *ndn) { ASSERT(!RW_LOCK_HELD(&odn->dn_struct_rwlock)); ASSERT(MUTEX_NOT_HELD(&odn->dn_mtx)); ASSERT(MUTEX_NOT_HELD(&odn->dn_dbufs_mtx)); /* Copy fields. */ ndn->dn_objset = odn->dn_objset; ndn->dn_object = odn->dn_object; ndn->dn_dbuf = odn->dn_dbuf; ndn->dn_handle = odn->dn_handle; ndn->dn_phys = odn->dn_phys; ndn->dn_type = odn->dn_type; ndn->dn_bonuslen = odn->dn_bonuslen; ndn->dn_bonustype = odn->dn_bonustype; ndn->dn_nblkptr = odn->dn_nblkptr; ndn->dn_checksum = odn->dn_checksum; ndn->dn_compress = odn->dn_compress; ndn->dn_nlevels = odn->dn_nlevels; ndn->dn_indblkshift = odn->dn_indblkshift; ndn->dn_datablkshift = odn->dn_datablkshift; ndn->dn_datablkszsec = odn->dn_datablkszsec; ndn->dn_datablksz = odn->dn_datablksz; ndn->dn_maxblkid = odn->dn_maxblkid; ndn->dn_num_slots = odn->dn_num_slots; memcpy(ndn->dn_next_type, odn->dn_next_type, sizeof (odn->dn_next_type)); memcpy(ndn->dn_next_nblkptr, odn->dn_next_nblkptr, sizeof (odn->dn_next_nblkptr)); memcpy(ndn->dn_next_nlevels, odn->dn_next_nlevels, sizeof (odn->dn_next_nlevels)); memcpy(ndn->dn_next_indblkshift, odn->dn_next_indblkshift, sizeof (odn->dn_next_indblkshift)); memcpy(ndn->dn_next_bonustype, odn->dn_next_bonustype, sizeof (odn->dn_next_bonustype)); memcpy(ndn->dn_rm_spillblk, odn->dn_rm_spillblk, sizeof (odn->dn_rm_spillblk)); memcpy(ndn->dn_next_bonuslen, odn->dn_next_bonuslen, sizeof (odn->dn_next_bonuslen)); memcpy(ndn->dn_next_blksz, odn->dn_next_blksz, sizeof (odn->dn_next_blksz)); memcpy(ndn->dn_next_maxblkid, odn->dn_next_maxblkid, sizeof (odn->dn_next_maxblkid)); for (int i = 0; i < TXG_SIZE; i++) { list_move_tail(&ndn->dn_dirty_records[i], &odn->dn_dirty_records[i]); } memcpy(ndn->dn_free_ranges, odn->dn_free_ranges, sizeof (odn->dn_free_ranges)); ndn->dn_allocated_txg = odn->dn_allocated_txg; ndn->dn_free_txg = odn->dn_free_txg; ndn->dn_assigned_txg = odn->dn_assigned_txg; ndn->dn_dirty_txg = odn->dn_dirty_txg; ndn->dn_dirtyctx = odn->dn_dirtyctx; ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset; ASSERT(zfs_refcount_count(&odn->dn_tx_holds) == 0); zfs_refcount_transfer(&ndn->dn_holds, &odn->dn_holds); ASSERT(avl_is_empty(&ndn->dn_dbufs)); avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs); ndn->dn_dbufs_count = odn->dn_dbufs_count; ndn->dn_bonus = odn->dn_bonus; ndn->dn_have_spill = odn->dn_have_spill; ndn->dn_zio = odn->dn_zio; ndn->dn_oldused = odn->dn_oldused; ndn->dn_oldflags = odn->dn_oldflags; ndn->dn_olduid = odn->dn_olduid; ndn->dn_oldgid = odn->dn_oldgid; ndn->dn_oldprojid = odn->dn_oldprojid; ndn->dn_newuid = odn->dn_newuid; ndn->dn_newgid = odn->dn_newgid; ndn->dn_newprojid = odn->dn_newprojid; ndn->dn_id_flags = odn->dn_id_flags; dmu_zfetch_init(&ndn->dn_zfetch, ndn); /* * Update back pointers. Updating the handle fixes the back pointer of * every descendant dbuf as well as the bonus dbuf. */ ASSERT(ndn->dn_handle->dnh_dnode == odn); ndn->dn_handle->dnh_dnode = ndn; /* * Invalidate the original dnode by clearing all of its back pointers. */ odn->dn_dbuf = NULL; odn->dn_handle = NULL; avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t), offsetof(dmu_buf_impl_t, db_link)); odn->dn_dbufs_count = 0; odn->dn_bonus = NULL; dmu_zfetch_fini(&odn->dn_zfetch); /* * Set the low bit of the objset pointer to ensure that dnode_move() * recognizes the dnode as invalid in any subsequent callback. */ POINTER_INVALIDATE(&odn->dn_objset); /* * Satisfy the destructor. */ for (int i = 0; i < TXG_SIZE; i++) { list_create(&odn->dn_dirty_records[i], sizeof (dbuf_dirty_record_t), offsetof(dbuf_dirty_record_t, dr_dirty_node)); odn->dn_free_ranges[i] = NULL; odn->dn_next_nlevels[i] = 0; odn->dn_next_indblkshift[i] = 0; odn->dn_next_bonustype[i] = 0; odn->dn_rm_spillblk[i] = 0; odn->dn_next_bonuslen[i] = 0; odn->dn_next_blksz[i] = 0; } odn->dn_allocated_txg = 0; odn->dn_free_txg = 0; odn->dn_assigned_txg = 0; odn->dn_dirty_txg = 0; odn->dn_dirtyctx = 0; odn->dn_dirtyctx_firstset = NULL; odn->dn_have_spill = B_FALSE; odn->dn_zio = NULL; odn->dn_oldused = 0; odn->dn_oldflags = 0; odn->dn_olduid = 0; odn->dn_oldgid = 0; odn->dn_oldprojid = ZFS_DEFAULT_PROJID; odn->dn_newuid = 0; odn->dn_newgid = 0; odn->dn_newprojid = ZFS_DEFAULT_PROJID; odn->dn_id_flags = 0; /* * Mark the dnode. */ ndn->dn_moved = 1; odn->dn_moved = (uint8_t)-1; } static kmem_cbrc_t dnode_move(void *buf, void *newbuf, size_t size, void *arg) { dnode_t *odn = buf, *ndn = newbuf; objset_t *os; int64_t refcount; uint32_t dbufs; /* * The dnode is on the objset's list of known dnodes if the objset * pointer is valid. We set the low bit of the objset pointer when * freeing the dnode to invalidate it, and the memory patterns written * by kmem (baddcafe and deadbeef) set at least one of the two low bits. * A newly created dnode sets the objset pointer last of all to indicate * that the dnode is known and in a valid state to be moved by this * function. */ os = odn->dn_objset; if (!POINTER_IS_VALID(os)) { DNODE_STAT_BUMP(dnode_move_invalid); return (KMEM_CBRC_DONT_KNOW); } /* * Ensure that the objset does not go away during the move. */ rw_enter(&os_lock, RW_WRITER); if (os != odn->dn_objset) { rw_exit(&os_lock); DNODE_STAT_BUMP(dnode_move_recheck1); return (KMEM_CBRC_DONT_KNOW); } /* * If the dnode is still valid, then so is the objset. We know that no * valid objset can be freed while we hold os_lock, so we can safely * ensure that the objset remains in use. */ mutex_enter(&os->os_lock); /* * Recheck the objset pointer in case the dnode was removed just before * acquiring the lock. */ if (os != odn->dn_objset) { mutex_exit(&os->os_lock); rw_exit(&os_lock); DNODE_STAT_BUMP(dnode_move_recheck2); return (KMEM_CBRC_DONT_KNOW); } /* * At this point we know that as long as we hold os->os_lock, the dnode * cannot be freed and fields within the dnode can be safely accessed. * The objset listing this dnode cannot go away as long as this dnode is * on its list. */ rw_exit(&os_lock); if (DMU_OBJECT_IS_SPECIAL(odn->dn_object)) { mutex_exit(&os->os_lock); DNODE_STAT_BUMP(dnode_move_special); return (KMEM_CBRC_NO); } ASSERT(odn->dn_dbuf != NULL); /* only "special" dnodes have no parent */ /* * Lock the dnode handle to prevent the dnode from obtaining any new * holds. This also prevents the descendant dbufs and the bonus dbuf * from accessing the dnode, so that we can discount their holds. The * handle is safe to access because we know that while the dnode cannot * go away, neither can its handle. Once we hold dnh_zrlock, we can * safely move any dnode referenced only by dbufs. */ if (!zrl_tryenter(&odn->dn_handle->dnh_zrlock)) { mutex_exit(&os->os_lock); DNODE_STAT_BUMP(dnode_move_handle); return (KMEM_CBRC_LATER); } /* * Ensure a consistent view of the dnode's holds and the dnode's dbufs. * We need to guarantee that there is a hold for every dbuf in order to * determine whether the dnode is actively referenced. Falsely matching * a dbuf to an active hold would lead to an unsafe move. It's possible * that a thread already having an active dnode hold is about to add a * dbuf, and we can't compare hold and dbuf counts while the add is in * progress. */ if (!rw_tryenter(&odn->dn_struct_rwlock, RW_WRITER)) { zrl_exit(&odn->dn_handle->dnh_zrlock); mutex_exit(&os->os_lock); DNODE_STAT_BUMP(dnode_move_rwlock); return (KMEM_CBRC_LATER); } /* * A dbuf may be removed (evicted) without an active dnode hold. In that * case, the dbuf count is decremented under the handle lock before the * dbuf's hold is released. This order ensures that if we count the hold * after the dbuf is removed but before its hold is released, we will * treat the unmatched hold as active and exit safely. If we count the * hold before the dbuf is removed, the hold is discounted, and the * removal is blocked until the move completes. */ refcount = zfs_refcount_count(&odn->dn_holds); ASSERT(refcount >= 0); dbufs = DN_DBUFS_COUNT(odn); /* We can't have more dbufs than dnode holds. */ ASSERT3U(dbufs, <=, refcount); DTRACE_PROBE3(dnode__move, dnode_t *, odn, int64_t, refcount, uint32_t, dbufs); if (refcount > dbufs) { rw_exit(&odn->dn_struct_rwlock); zrl_exit(&odn->dn_handle->dnh_zrlock); mutex_exit(&os->os_lock); DNODE_STAT_BUMP(dnode_move_active); return (KMEM_CBRC_LATER); } rw_exit(&odn->dn_struct_rwlock); /* * At this point we know that anyone with a hold on the dnode is not * actively referencing it. The dnode is known and in a valid state to * move. We're holding the locks needed to execute the critical section. */ dnode_move_impl(odn, ndn); list_link_replace(&odn->dn_link, &ndn->dn_link); /* If the dnode was safe to move, the refcount cannot have changed. */ ASSERT(refcount == zfs_refcount_count(&ndn->dn_holds)); ASSERT(dbufs == DN_DBUFS_COUNT(ndn)); zrl_exit(&ndn->dn_handle->dnh_zrlock); /* handle has moved */ mutex_exit(&os->os_lock); return (KMEM_CBRC_YES); } #endif /* _KERNEL */ static void dnode_slots_hold(dnode_children_t *children, int idx, int slots) { ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); for (int i = idx; i < idx + slots; i++) { dnode_handle_t *dnh = &children->dnc_children[i]; zrl_add(&dnh->dnh_zrlock); } } static void dnode_slots_rele(dnode_children_t *children, int idx, int slots) { ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); for (int i = idx; i < idx + slots; i++) { dnode_handle_t *dnh = &children->dnc_children[i]; if (zrl_is_locked(&dnh->dnh_zrlock)) zrl_exit(&dnh->dnh_zrlock); else zrl_remove(&dnh->dnh_zrlock); } } static int dnode_slots_tryenter(dnode_children_t *children, int idx, int slots) { ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); for (int i = idx; i < idx + slots; i++) { dnode_handle_t *dnh = &children->dnc_children[i]; if (!zrl_tryenter(&dnh->dnh_zrlock)) { for (int j = idx; j < i; j++) { dnh = &children->dnc_children[j]; zrl_exit(&dnh->dnh_zrlock); } return (0); } } return (1); } static void dnode_set_slots(dnode_children_t *children, int idx, int slots, void *ptr) { ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); for (int i = idx; i < idx + slots; i++) { dnode_handle_t *dnh = &children->dnc_children[i]; dnh->dnh_dnode = ptr; } } static boolean_t dnode_check_slots_free(dnode_children_t *children, int idx, int slots) { ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); /* * If all dnode slots are either already free or * evictable return B_TRUE. */ for (int i = idx; i < idx + slots; i++) { dnode_handle_t *dnh = &children->dnc_children[i]; dnode_t *dn = dnh->dnh_dnode; if (dn == DN_SLOT_FREE) { continue; } else if (DN_SLOT_IS_PTR(dn)) { mutex_enter(&dn->dn_mtx); boolean_t can_free = (dn->dn_type == DMU_OT_NONE && zfs_refcount_is_zero(&dn->dn_holds) && !DNODE_IS_DIRTY(dn)); mutex_exit(&dn->dn_mtx); if (!can_free) return (B_FALSE); else continue; } else { return (B_FALSE); } } return (B_TRUE); } static void dnode_reclaim_slots(dnode_children_t *children, int idx, int slots) { ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); for (int i = idx; i < idx + slots; i++) { dnode_handle_t *dnh = &children->dnc_children[i]; ASSERT(zrl_is_locked(&dnh->dnh_zrlock)); if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { ASSERT3S(dnh->dnh_dnode->dn_type, ==, DMU_OT_NONE); dnode_destroy(dnh->dnh_dnode); dnh->dnh_dnode = DN_SLOT_FREE; } } } void dnode_free_interior_slots(dnode_t *dn) { dnode_children_t *children = dmu_buf_get_user(&dn->dn_dbuf->db); int epb = dn->dn_dbuf->db.db_size >> DNODE_SHIFT; int idx = (dn->dn_object & (epb - 1)) + 1; int slots = dn->dn_num_slots - 1; if (slots == 0) return; ASSERT3S(idx + slots, <=, DNODES_PER_BLOCK); while (!dnode_slots_tryenter(children, idx, slots)) { DNODE_STAT_BUMP(dnode_free_interior_lock_retry); - cond_resched(); + kpreempt(KPREEMPT_SYNC); } dnode_set_slots(children, idx, slots, DN_SLOT_FREE); dnode_slots_rele(children, idx, slots); } void dnode_special_close(dnode_handle_t *dnh) { dnode_t *dn = dnh->dnh_dnode; /* * Ensure dnode_rele_and_unlock() has released dn_mtx, after final * zfs_refcount_remove() */ mutex_enter(&dn->dn_mtx); if (zfs_refcount_count(&dn->dn_holds) > 0) cv_wait(&dn->dn_nodnholds, &dn->dn_mtx); mutex_exit(&dn->dn_mtx); ASSERT3U(zfs_refcount_count(&dn->dn_holds), ==, 0); ASSERT(dn->dn_dbuf == NULL || dmu_buf_get_user(&dn->dn_dbuf->db) == NULL); zrl_add(&dnh->dnh_zrlock); dnode_destroy(dn); /* implicit zrl_remove() */ zrl_destroy(&dnh->dnh_zrlock); dnh->dnh_dnode = NULL; } void dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object, dnode_handle_t *dnh) { dnode_t *dn; zrl_init(&dnh->dnh_zrlock); VERIFY3U(1, ==, zrl_tryenter(&dnh->dnh_zrlock)); dn = dnode_create(os, dnp, NULL, object, dnh); DNODE_VERIFY(dn); zrl_exit(&dnh->dnh_zrlock); } static void dnode_buf_evict_async(void *dbu) { dnode_children_t *dnc = dbu; DNODE_STAT_BUMP(dnode_buf_evict); for (int i = 0; i < dnc->dnc_count; i++) { dnode_handle_t *dnh = &dnc->dnc_children[i]; dnode_t *dn; /* * The dnode handle lock guards against the dnode moving to * another valid address, so there is no need here to guard * against changes to or from NULL. */ if (!DN_SLOT_IS_PTR(dnh->dnh_dnode)) { zrl_destroy(&dnh->dnh_zrlock); dnh->dnh_dnode = DN_SLOT_UNINIT; continue; } zrl_add(&dnh->dnh_zrlock); dn = dnh->dnh_dnode; /* * If there are holds on this dnode, then there should * be holds on the dnode's containing dbuf as well; thus * it wouldn't be eligible for eviction and this function * would not have been called. */ ASSERT(zfs_refcount_is_zero(&dn->dn_holds)); ASSERT(zfs_refcount_is_zero(&dn->dn_tx_holds)); dnode_destroy(dn); /* implicit zrl_remove() for first slot */ zrl_destroy(&dnh->dnh_zrlock); dnh->dnh_dnode = DN_SLOT_UNINIT; } kmem_free(dnc, sizeof (dnode_children_t) + dnc->dnc_count * sizeof (dnode_handle_t)); } /* * When the DNODE_MUST_BE_FREE flag is set, the "slots" parameter is used * to ensure the hole at the specified object offset is large enough to * hold the dnode being created. The slots parameter is also used to ensure * a dnode does not span multiple dnode blocks. In both of these cases, if * a failure occurs, ENOSPC is returned. Keep in mind, these failure cases * are only possible when using DNODE_MUST_BE_FREE. * * If the DNODE_MUST_BE_ALLOCATED flag is set, "slots" must be 0. * dnode_hold_impl() will check if the requested dnode is already consumed * as an extra dnode slot by an large dnode, in which case it returns * ENOENT. * * If the DNODE_DRY_RUN flag is set, we don't actually hold the dnode, just * return whether the hold would succeed or not. tag and dnp should set to * NULL in this case. * * errors: * EINVAL - Invalid object number or flags. * ENOSPC - Hole too small to fulfill "slots" request (DNODE_MUST_BE_FREE) * EEXIST - Refers to an allocated dnode (DNODE_MUST_BE_FREE) * - Refers to a freeing dnode (DNODE_MUST_BE_FREE) * - Refers to an interior dnode slot (DNODE_MUST_BE_ALLOCATED) * ENOENT - The requested dnode is not allocated (DNODE_MUST_BE_ALLOCATED) * - The requested dnode is being freed (DNODE_MUST_BE_ALLOCATED) * EIO - I/O error when reading the meta dnode dbuf. * * succeeds even for free dnodes. */ int dnode_hold_impl(objset_t *os, uint64_t object, int flag, int slots, const void *tag, dnode_t **dnp) { int epb, idx, err; int drop_struct_lock = FALSE; int type; uint64_t blk; dnode_t *mdn, *dn; dmu_buf_impl_t *db; dnode_children_t *dnc; dnode_phys_t *dn_block; dnode_handle_t *dnh; ASSERT(!(flag & DNODE_MUST_BE_ALLOCATED) || (slots == 0)); ASSERT(!(flag & DNODE_MUST_BE_FREE) || (slots > 0)); IMPLY(flag & DNODE_DRY_RUN, (tag == NULL) && (dnp == NULL)); /* * If you are holding the spa config lock as writer, you shouldn't * be asking the DMU to do *anything* unless it's the root pool * which may require us to read from the root filesystem while * holding some (not all) of the locks as writer. */ ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0 || (spa_is_root(os->os_spa) && spa_config_held(os->os_spa, SCL_STATE, RW_WRITER))); ASSERT((flag & DNODE_MUST_BE_ALLOCATED) || (flag & DNODE_MUST_BE_FREE)); if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT || object == DMU_PROJECTUSED_OBJECT) { if (object == DMU_USERUSED_OBJECT) dn = DMU_USERUSED_DNODE(os); else if (object == DMU_GROUPUSED_OBJECT) dn = DMU_GROUPUSED_DNODE(os); else dn = DMU_PROJECTUSED_DNODE(os); if (dn == NULL) return (SET_ERROR(ENOENT)); type = dn->dn_type; if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) return (SET_ERROR(ENOENT)); if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE) return (SET_ERROR(EEXIST)); DNODE_VERIFY(dn); /* Don't actually hold if dry run, just return 0 */ if (!(flag & DNODE_DRY_RUN)) { (void) zfs_refcount_add(&dn->dn_holds, tag); *dnp = dn; } return (0); } if (object == 0 || object >= DN_MAX_OBJECT) return (SET_ERROR(EINVAL)); mdn = DMU_META_DNODE(os); ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT); DNODE_VERIFY(mdn); if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) { rw_enter(&mdn->dn_struct_rwlock, RW_READER); drop_struct_lock = TRUE; } blk = dbuf_whichblock(mdn, 0, object * sizeof (dnode_phys_t)); db = dbuf_hold(mdn, blk, FTAG); if (drop_struct_lock) rw_exit(&mdn->dn_struct_rwlock); if (db == NULL) { DNODE_STAT_BUMP(dnode_hold_dbuf_hold); return (SET_ERROR(EIO)); } /* * We do not need to decrypt to read the dnode so it doesn't matter * if we get the encrypted or decrypted version. */ err = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_NO_DECRYPT | DB_RF_NOPREFETCH); if (err) { DNODE_STAT_BUMP(dnode_hold_dbuf_read); dbuf_rele(db, FTAG); return (err); } ASSERT3U(db->db.db_size, >=, 1<db.db_size >> DNODE_SHIFT; idx = object & (epb - 1); dn_block = (dnode_phys_t *)db->db.db_data; ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE); dnc = dmu_buf_get_user(&db->db); dnh = NULL; if (dnc == NULL) { dnode_children_t *winner; int skip = 0; dnc = kmem_zalloc(sizeof (dnode_children_t) + epb * sizeof (dnode_handle_t), KM_SLEEP); dnc->dnc_count = epb; dnh = &dnc->dnc_children[0]; /* Initialize dnode slot status from dnode_phys_t */ for (int i = 0; i < epb; i++) { zrl_init(&dnh[i].dnh_zrlock); if (skip) { skip--; continue; } if (dn_block[i].dn_type != DMU_OT_NONE) { int interior = dn_block[i].dn_extra_slots; dnode_set_slots(dnc, i, 1, DN_SLOT_ALLOCATED); dnode_set_slots(dnc, i + 1, interior, DN_SLOT_INTERIOR); skip = interior; } else { dnh[i].dnh_dnode = DN_SLOT_FREE; skip = 0; } } dmu_buf_init_user(&dnc->dnc_dbu, NULL, dnode_buf_evict_async, NULL); winner = dmu_buf_set_user(&db->db, &dnc->dnc_dbu); if (winner != NULL) { for (int i = 0; i < epb; i++) zrl_destroy(&dnh[i].dnh_zrlock); kmem_free(dnc, sizeof (dnode_children_t) + epb * sizeof (dnode_handle_t)); dnc = winner; } } ASSERT(dnc->dnc_count == epb); if (flag & DNODE_MUST_BE_ALLOCATED) { slots = 1; dnode_slots_hold(dnc, idx, slots); dnh = &dnc->dnc_children[idx]; if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { dn = dnh->dnh_dnode; } else if (dnh->dnh_dnode == DN_SLOT_INTERIOR) { DNODE_STAT_BUMP(dnode_hold_alloc_interior); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (SET_ERROR(EEXIST)); } else if (dnh->dnh_dnode != DN_SLOT_ALLOCATED) { DNODE_STAT_BUMP(dnode_hold_alloc_misses); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (SET_ERROR(ENOENT)); } else { dnode_slots_rele(dnc, idx, slots); while (!dnode_slots_tryenter(dnc, idx, slots)) { DNODE_STAT_BUMP(dnode_hold_alloc_lock_retry); - cond_resched(); + kpreempt(KPREEMPT_SYNC); } /* * Someone else won the race and called dnode_create() * after we checked DN_SLOT_IS_PTR() above but before * we acquired the lock. */ if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { DNODE_STAT_BUMP(dnode_hold_alloc_lock_misses); dn = dnh->dnh_dnode; } else { dn = dnode_create(os, dn_block + idx, db, object, dnh); } } mutex_enter(&dn->dn_mtx); if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg != 0) { DNODE_STAT_BUMP(dnode_hold_alloc_type_none); mutex_exit(&dn->dn_mtx); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (SET_ERROR(ENOENT)); } /* Don't actually hold if dry run, just return 0 */ if (flag & DNODE_DRY_RUN) { mutex_exit(&dn->dn_mtx); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (0); } DNODE_STAT_BUMP(dnode_hold_alloc_hits); } else if (flag & DNODE_MUST_BE_FREE) { if (idx + slots - 1 >= DNODES_PER_BLOCK) { DNODE_STAT_BUMP(dnode_hold_free_overflow); dbuf_rele(db, FTAG); return (SET_ERROR(ENOSPC)); } dnode_slots_hold(dnc, idx, slots); if (!dnode_check_slots_free(dnc, idx, slots)) { DNODE_STAT_BUMP(dnode_hold_free_misses); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (SET_ERROR(ENOSPC)); } dnode_slots_rele(dnc, idx, slots); while (!dnode_slots_tryenter(dnc, idx, slots)) { DNODE_STAT_BUMP(dnode_hold_free_lock_retry); - cond_resched(); + kpreempt(KPREEMPT_SYNC); } if (!dnode_check_slots_free(dnc, idx, slots)) { DNODE_STAT_BUMP(dnode_hold_free_lock_misses); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (SET_ERROR(ENOSPC)); } /* * Allocated but otherwise free dnodes which would * be in the interior of a multi-slot dnodes need * to be freed. Single slot dnodes can be safely * re-purposed as a performance optimization. */ if (slots > 1) dnode_reclaim_slots(dnc, idx + 1, slots - 1); dnh = &dnc->dnc_children[idx]; if (DN_SLOT_IS_PTR(dnh->dnh_dnode)) { dn = dnh->dnh_dnode; } else { dn = dnode_create(os, dn_block + idx, db, object, dnh); } mutex_enter(&dn->dn_mtx); if (!zfs_refcount_is_zero(&dn->dn_holds) || dn->dn_free_txg) { DNODE_STAT_BUMP(dnode_hold_free_refcount); mutex_exit(&dn->dn_mtx); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (SET_ERROR(EEXIST)); } /* Don't actually hold if dry run, just return 0 */ if (flag & DNODE_DRY_RUN) { mutex_exit(&dn->dn_mtx); dnode_slots_rele(dnc, idx, slots); dbuf_rele(db, FTAG); return (0); } dnode_set_slots(dnc, idx + 1, slots - 1, DN_SLOT_INTERIOR); DNODE_STAT_BUMP(dnode_hold_free_hits); } else { dbuf_rele(db, FTAG); return (SET_ERROR(EINVAL)); } ASSERT0(dn->dn_free_txg); if (zfs_refcount_add(&dn->dn_holds, tag) == 1) dbuf_add_ref(db, dnh); mutex_exit(&dn->dn_mtx); /* Now we can rely on the hold to prevent the dnode from moving. */ dnode_slots_rele(dnc, idx, slots); DNODE_VERIFY(dn); ASSERT3P(dnp, !=, NULL); ASSERT3P(dn->dn_dbuf, ==, db); ASSERT3U(dn->dn_object, ==, object); dbuf_rele(db, FTAG); *dnp = dn; return (0); } /* * Return held dnode if the object is allocated, NULL if not. */ int dnode_hold(objset_t *os, uint64_t object, const void *tag, dnode_t **dnp) { return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0, tag, dnp)); } /* * Can only add a reference if there is already at least one * reference on the dnode. Returns FALSE if unable to add a * new reference. */ boolean_t dnode_add_ref(dnode_t *dn, const void *tag) { mutex_enter(&dn->dn_mtx); if (zfs_refcount_is_zero(&dn->dn_holds)) { mutex_exit(&dn->dn_mtx); return (FALSE); } VERIFY(1 < zfs_refcount_add(&dn->dn_holds, tag)); mutex_exit(&dn->dn_mtx); return (TRUE); } void dnode_rele(dnode_t *dn, const void *tag) { mutex_enter(&dn->dn_mtx); dnode_rele_and_unlock(dn, tag, B_FALSE); } void dnode_rele_and_unlock(dnode_t *dn, const void *tag, boolean_t evicting) { uint64_t refs; /* Get while the hold prevents the dnode from moving. */ dmu_buf_impl_t *db = dn->dn_dbuf; dnode_handle_t *dnh = dn->dn_handle; refs = zfs_refcount_remove(&dn->dn_holds, tag); if (refs == 0) cv_broadcast(&dn->dn_nodnholds); mutex_exit(&dn->dn_mtx); /* dnode could get destroyed at this point, so don't use it anymore */ /* * It's unsafe to release the last hold on a dnode by dnode_rele() or * indirectly by dbuf_rele() while relying on the dnode handle to * prevent the dnode from moving, since releasing the last hold could * result in the dnode's parent dbuf evicting its dnode handles. For * that reason anyone calling dnode_rele() or dbuf_rele() without some * other direct or indirect hold on the dnode must first drop the dnode * handle. */ #ifdef ZFS_DEBUG ASSERT(refs > 0 || dnh->dnh_zrlock.zr_owner != curthread); #endif /* NOTE: the DNODE_DNODE does not have a dn_dbuf */ if (refs == 0 && db != NULL) { /* * Another thread could add a hold to the dnode handle in * dnode_hold_impl() while holding the parent dbuf. Since the * hold on the parent dbuf prevents the handle from being * destroyed, the hold on the handle is OK. We can't yet assert * that the handle has zero references, but that will be * asserted anyway when the handle gets destroyed. */ mutex_enter(&db->db_mtx); dbuf_rele_and_unlock(db, dnh, evicting); } } /* * Test whether we can create a dnode at the specified location. */ int dnode_try_claim(objset_t *os, uint64_t object, int slots) { return (dnode_hold_impl(os, object, DNODE_MUST_BE_FREE | DNODE_DRY_RUN, slots, NULL, NULL)); } /* * Checks if the dnode contains any uncommitted dirty records. */ boolean_t dnode_is_dirty(dnode_t *dn) { mutex_enter(&dn->dn_mtx); for (int i = 0; i < TXG_SIZE; i++) { if (multilist_link_active(&dn->dn_dirty_link[i])) { mutex_exit(&dn->dn_mtx); return (B_TRUE); } } mutex_exit(&dn->dn_mtx); return (B_FALSE); } void dnode_setdirty(dnode_t *dn, dmu_tx_t *tx) { objset_t *os = dn->dn_objset; uint64_t txg = tx->tx_txg; if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) { dsl_dataset_dirty(os->os_dsl_dataset, tx); return; } DNODE_VERIFY(dn); #ifdef ZFS_DEBUG mutex_enter(&dn->dn_mtx); ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg); ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg); mutex_exit(&dn->dn_mtx); #endif /* * Determine old uid/gid when necessary */ dmu_objset_userquota_get_ids(dn, B_TRUE, tx); multilist_t *dirtylist = &os->os_dirty_dnodes[txg & TXG_MASK]; multilist_sublist_t *mls = multilist_sublist_lock_obj(dirtylist, dn); /* * If we are already marked dirty, we're done. */ if (multilist_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) { multilist_sublist_unlock(mls); return; } ASSERT(!zfs_refcount_is_zero(&dn->dn_holds) || !avl_is_empty(&dn->dn_dbufs)); ASSERT(dn->dn_datablksz != 0); ASSERT0(dn->dn_next_bonuslen[txg & TXG_MASK]); ASSERT0(dn->dn_next_blksz[txg & TXG_MASK]); ASSERT0(dn->dn_next_bonustype[txg & TXG_MASK]); dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n", (u_longlong_t)dn->dn_object, (u_longlong_t)txg); multilist_sublist_insert_head(mls, dn); multilist_sublist_unlock(mls); /* * The dnode maintains a hold on its containing dbuf as * long as there are holds on it. Each instantiated child * dbuf maintains a hold on the dnode. When the last child * drops its hold, the dnode will drop its hold on the * containing dbuf. We add a "dirty hold" here so that the * dnode will hang around after we finish processing its * children. */ VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg)); (void) dbuf_dirty(dn->dn_dbuf, tx); dsl_dataset_dirty(os->os_dsl_dataset, tx); } void dnode_free(dnode_t *dn, dmu_tx_t *tx) { mutex_enter(&dn->dn_mtx); if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) { mutex_exit(&dn->dn_mtx); return; } dn->dn_free_txg = tx->tx_txg; mutex_exit(&dn->dn_mtx); dnode_setdirty(dn, tx); } /* * Try to change the block size for the indicated dnode. This can only * succeed if there are no blocks allocated or dirty beyond first block */ int dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx) { dmu_buf_impl_t *db; int err; ASSERT3U(size, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset))); if (size == 0) size = SPA_MINBLOCKSIZE; else size = P2ROUNDUP(size, SPA_MINBLOCKSIZE); if (ibs == dn->dn_indblkshift) ibs = 0; if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0) return (0); rw_enter(&dn->dn_struct_rwlock, RW_WRITER); /* Check for any allocated blocks beyond the first */ if (dn->dn_maxblkid != 0) goto fail; mutex_enter(&dn->dn_dbufs_mtx); for (db = avl_first(&dn->dn_dbufs); db != NULL; db = AVL_NEXT(&dn->dn_dbufs, db)) { if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID && db->db_blkid != DMU_SPILL_BLKID) { mutex_exit(&dn->dn_dbufs_mtx); goto fail; } } mutex_exit(&dn->dn_dbufs_mtx); if (ibs && dn->dn_nlevels != 1) goto fail; /* resize the old block */ err = dbuf_hold_impl(dn, 0, 0, TRUE, FALSE, FTAG, &db); if (err == 0) { dbuf_new_size(db, size, tx); } else if (err != ENOENT) { goto fail; } dnode_setdblksz(dn, size); dnode_setdirty(dn, tx); dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size; if (ibs) { dn->dn_indblkshift = ibs; dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs; } /* release after we have fixed the blocksize in the dnode */ if (db) dbuf_rele(db, FTAG); rw_exit(&dn->dn_struct_rwlock); return (0); fail: rw_exit(&dn->dn_struct_rwlock); return (SET_ERROR(ENOTSUP)); } static void dnode_set_nlevels_impl(dnode_t *dn, int new_nlevels, dmu_tx_t *tx) { uint64_t txgoff = tx->tx_txg & TXG_MASK; int old_nlevels = dn->dn_nlevels; dmu_buf_impl_t *db; list_t *list; dbuf_dirty_record_t *new, *dr, *dr_next; ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock)); ASSERT3U(new_nlevels, >, dn->dn_nlevels); dn->dn_nlevels = new_nlevels; ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]); dn->dn_next_nlevels[txgoff] = new_nlevels; /* dirty the left indirects */ db = dbuf_hold_level(dn, old_nlevels, 0, FTAG); ASSERT(db != NULL); new = dbuf_dirty(db, tx); dbuf_rele(db, FTAG); /* transfer the dirty records to the new indirect */ mutex_enter(&dn->dn_mtx); mutex_enter(&new->dt.di.dr_mtx); list = &dn->dn_dirty_records[txgoff]; for (dr = list_head(list); dr; dr = dr_next) { dr_next = list_next(&dn->dn_dirty_records[txgoff], dr); IMPLY(dr->dr_dbuf == NULL, old_nlevels == 1); if (dr->dr_dbuf == NULL || (dr->dr_dbuf->db_level == old_nlevels - 1 && dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID && dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID)) { list_remove(&dn->dn_dirty_records[txgoff], dr); list_insert_tail(&new->dt.di.dr_children, dr); dr->dr_parent = new; } } mutex_exit(&new->dt.di.dr_mtx); mutex_exit(&dn->dn_mtx); } int dnode_set_nlevels(dnode_t *dn, int nlevels, dmu_tx_t *tx) { int ret = 0; rw_enter(&dn->dn_struct_rwlock, RW_WRITER); if (dn->dn_nlevels == nlevels) { ret = 0; goto out; } else if (nlevels < dn->dn_nlevels) { ret = SET_ERROR(EINVAL); goto out; } dnode_set_nlevels_impl(dn, nlevels, tx); out: rw_exit(&dn->dn_struct_rwlock); return (ret); } /* read-holding callers must not rely on the lock being continuously held */ void dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read, boolean_t force) { int epbs, new_nlevels; uint64_t sz; ASSERT(blkid != DMU_BONUS_BLKID); ASSERT(have_read ? RW_READ_HELD(&dn->dn_struct_rwlock) : RW_WRITE_HELD(&dn->dn_struct_rwlock)); /* * if we have a read-lock, check to see if we need to do any work * before upgrading to a write-lock. */ if (have_read) { if (blkid <= dn->dn_maxblkid) return; if (!rw_tryupgrade(&dn->dn_struct_rwlock)) { rw_exit(&dn->dn_struct_rwlock); rw_enter(&dn->dn_struct_rwlock, RW_WRITER); } } /* * Raw sends (indicated by the force flag) require that we take the * given blkid even if the value is lower than the current value. */ if (!force && blkid <= dn->dn_maxblkid) goto out; /* * We use the (otherwise unused) top bit of dn_next_maxblkid[txgoff] * to indicate that this field is set. This allows us to set the * maxblkid to 0 on an existing object in dnode_sync(). */ dn->dn_maxblkid = blkid; dn->dn_next_maxblkid[tx->tx_txg & TXG_MASK] = blkid | DMU_NEXT_MAXBLKID_SET; /* * Compute the number of levels necessary to support the new maxblkid. * Raw sends will ensure nlevels is set correctly for us. */ new_nlevels = 1; epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; for (sz = dn->dn_nblkptr; sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs) new_nlevels++; ASSERT3U(new_nlevels, <=, DN_MAX_LEVELS); if (!force) { if (new_nlevels > dn->dn_nlevels) dnode_set_nlevels_impl(dn, new_nlevels, tx); } else { ASSERT3U(dn->dn_nlevels, >=, new_nlevels); } out: if (have_read) rw_downgrade(&dn->dn_struct_rwlock); } static void dnode_dirty_l1(dnode_t *dn, uint64_t l1blkid, dmu_tx_t *tx) { dmu_buf_impl_t *db = dbuf_hold_level(dn, 1, l1blkid, FTAG); if (db != NULL) { dmu_buf_will_dirty(&db->db, tx); dbuf_rele(db, FTAG); } } /* * Dirty all the in-core level-1 dbufs in the range specified by start_blkid * and end_blkid. */ static void dnode_dirty_l1range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid, dmu_tx_t *tx) { dmu_buf_impl_t *db_search; dmu_buf_impl_t *db; avl_index_t where; db_search = kmem_zalloc(sizeof (dmu_buf_impl_t), KM_SLEEP); mutex_enter(&dn->dn_dbufs_mtx); db_search->db_level = 1; db_search->db_blkid = start_blkid + 1; db_search->db_state = DB_SEARCH; for (;;) { db = avl_find(&dn->dn_dbufs, db_search, &where); if (db == NULL) db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); if (db == NULL || db->db_level != 1 || db->db_blkid >= end_blkid) { break; } /* * Setup the next blkid we want to search for. */ db_search->db_blkid = db->db_blkid + 1; ASSERT3U(db->db_blkid, >=, start_blkid); /* * If the dbuf transitions to DB_EVICTING while we're trying * to dirty it, then we will be unable to discover it in * the dbuf hash table. This will result in a call to * dbuf_create() which needs to acquire the dn_dbufs_mtx * lock. To avoid a deadlock, we drop the lock before * dirtying the level-1 dbuf. */ mutex_exit(&dn->dn_dbufs_mtx); dnode_dirty_l1(dn, db->db_blkid, tx); mutex_enter(&dn->dn_dbufs_mtx); } #ifdef ZFS_DEBUG /* * Walk all the in-core level-1 dbufs and verify they have been dirtied. */ db_search->db_level = 1; db_search->db_blkid = start_blkid + 1; db_search->db_state = DB_SEARCH; db = avl_find(&dn->dn_dbufs, db_search, &where); if (db == NULL) db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER); for (; db != NULL; db = AVL_NEXT(&dn->dn_dbufs, db)) { if (db->db_level != 1 || db->db_blkid >= end_blkid) break; if (db->db_state != DB_EVICTING) ASSERT(db->db_dirtycnt > 0); } #endif kmem_free(db_search, sizeof (dmu_buf_impl_t)); mutex_exit(&dn->dn_dbufs_mtx); } void dnode_set_dirtyctx(dnode_t *dn, dmu_tx_t *tx, const void *tag) { /* * Don't set dirtyctx to SYNC if we're just modifying this as we * initialize the objset. */ if (dn->dn_dirtyctx == DN_UNDIRTIED) { dsl_dataset_t *ds = dn->dn_objset->os_dsl_dataset; if (ds != NULL) { rrw_enter(&ds->ds_bp_rwlock, RW_READER, tag); } if (!BP_IS_HOLE(dn->dn_objset->os_rootbp)) { if (dmu_tx_is_syncing(tx)) dn->dn_dirtyctx = DN_DIRTY_SYNC; else dn->dn_dirtyctx = DN_DIRTY_OPEN; dn->dn_dirtyctx_firstset = tag; } if (ds != NULL) { rrw_exit(&ds->ds_bp_rwlock, tag); } } } static void dnode_partial_zero(dnode_t *dn, uint64_t off, uint64_t blkoff, uint64_t len, dmu_tx_t *tx) { dmu_buf_impl_t *db; int res; rw_enter(&dn->dn_struct_rwlock, RW_READER); res = dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off), TRUE, FALSE, FTAG, &db); rw_exit(&dn->dn_struct_rwlock); if (res == 0) { db_lock_type_t dblt; boolean_t dirty; dblt = dmu_buf_lock_parent(db, RW_READER, FTAG); /* don't dirty if not on disk and not dirty */ dirty = !list_is_empty(&db->db_dirty_records) || (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr)); dmu_buf_unlock_parent(db, dblt, FTAG); if (dirty) { caddr_t data; dmu_buf_will_dirty(&db->db, tx); data = db->db.db_data; memset(data + blkoff, 0, len); } dbuf_rele(db, FTAG); } } void dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx) { uint64_t blkoff, blkid, nblks; int blksz, blkshift, head, tail; int trunc = FALSE; int epbs; blksz = dn->dn_datablksz; blkshift = dn->dn_datablkshift; epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT; if (len == DMU_OBJECT_END) { len = UINT64_MAX - off; trunc = TRUE; } /* * First, block align the region to free: */ if (ISP2(blksz)) { head = P2NPHASE(off, blksz); blkoff = P2PHASE(off, blksz); if ((off >> blkshift) > dn->dn_maxblkid) return; } else { ASSERT(dn->dn_maxblkid == 0); if (off == 0 && len >= blksz) { /* * Freeing the whole block; fast-track this request. */ blkid = 0; nblks = 1; if (dn->dn_nlevels > 1) { rw_enter(&dn->dn_struct_rwlock, RW_WRITER); dnode_dirty_l1(dn, 0, tx); rw_exit(&dn->dn_struct_rwlock); } goto done; } else if (off >= blksz) { /* Freeing past end-of-data */ return; } else { /* Freeing part of the block. */ head = blksz - off; ASSERT3U(head, >, 0); } blkoff = off; } /* zero out any partial block data at the start of the range */ if (head) { ASSERT3U(blkoff + head, ==, blksz); if (len < head) head = len; dnode_partial_zero(dn, off, blkoff, head, tx); off += head; len -= head; } /* If the range was less than one block, we're done */ if (len == 0) return; /* If the remaining range is past end of file, we're done */ if ((off >> blkshift) > dn->dn_maxblkid) return; ASSERT(ISP2(blksz)); if (trunc) tail = 0; else tail = P2PHASE(len, blksz); ASSERT0(P2PHASE(off, blksz)); /* zero out any partial block data at the end of the range */ if (tail) { if (len < tail) tail = len; dnode_partial_zero(dn, off + len, 0, tail, tx); len -= tail; } /* If the range did not include a full block, we are done */ if (len == 0) return; ASSERT(IS_P2ALIGNED(off, blksz)); ASSERT(trunc || IS_P2ALIGNED(len, blksz)); blkid = off >> blkshift; nblks = len >> blkshift; if (trunc) nblks += 1; /* * Dirty all the indirect blocks in this range. Note that only * the first and last indirect blocks can actually be written * (if they were partially freed) -- they must be dirtied, even if * they do not exist on disk yet. The interior blocks will * be freed by free_children(), so they will not actually be written. * Even though these interior blocks will not be written, we * dirty them for two reasons: * * - It ensures that the indirect blocks remain in memory until * syncing context. (They have already been prefetched by * dmu_tx_hold_free(), so we don't have to worry about reading * them serially here.) * * - The dirty space accounting will put pressure on the txg sync * mechanism to begin syncing, and to delay transactions if there * is a large amount of freeing. Even though these indirect * blocks will not be written, we could need to write the same * amount of space if we copy the freed BPs into deadlists. */ if (dn->dn_nlevels > 1) { rw_enter(&dn->dn_struct_rwlock, RW_WRITER); uint64_t first, last; first = blkid >> epbs; dnode_dirty_l1(dn, first, tx); if (trunc) last = dn->dn_maxblkid >> epbs; else last = (blkid + nblks - 1) >> epbs; if (last != first) dnode_dirty_l1(dn, last, tx); dnode_dirty_l1range(dn, first, last, tx); int shift = dn->dn_datablkshift + dn->dn_indblkshift - SPA_BLKPTRSHIFT; for (uint64_t i = first + 1; i < last; i++) { /* * Set i to the blockid of the next non-hole * level-1 indirect block at or after i. Note * that dnode_next_offset() operates in terms of * level-0-equivalent bytes. */ uint64_t ibyte = i << shift; int err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK, &ibyte, 2, 1, 0); i = ibyte >> shift; if (i >= last) break; /* * Normally we should not see an error, either * from dnode_next_offset() or dbuf_hold_level() * (except for ESRCH from dnode_next_offset). * If there is an i/o error, then when we read * this block in syncing context, it will use * ZIO_FLAG_MUSTSUCCEED, and thus hang/panic according * to the "failmode" property. dnode_next_offset() * doesn't have a flag to indicate MUSTSUCCEED. */ if (err != 0) break; dnode_dirty_l1(dn, i, tx); } rw_exit(&dn->dn_struct_rwlock); } done: /* * Add this range to the dnode range list. * We will finish up this free operation in the syncing phase. */ mutex_enter(&dn->dn_mtx); { int txgoff = tx->tx_txg & TXG_MASK; if (dn->dn_free_ranges[txgoff] == NULL) { dn->dn_free_ranges[txgoff] = range_tree_create(NULL, RANGE_SEG64, NULL, 0, 0); } range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks); range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks); } dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n", (u_longlong_t)blkid, (u_longlong_t)nblks, (u_longlong_t)tx->tx_txg); mutex_exit(&dn->dn_mtx); dbuf_free_range(dn, blkid, blkid + nblks - 1, tx); dnode_setdirty(dn, tx); } static boolean_t dnode_spill_freed(dnode_t *dn) { int i; mutex_enter(&dn->dn_mtx); for (i = 0; i < TXG_SIZE; i++) { if (dn->dn_rm_spillblk[i] == DN_KILL_SPILLBLK) break; } mutex_exit(&dn->dn_mtx); return (i < TXG_SIZE); } /* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */ uint64_t dnode_block_freed(dnode_t *dn, uint64_t blkid) { void *dp = spa_get_dsl(dn->dn_objset->os_spa); int i; if (blkid == DMU_BONUS_BLKID) return (FALSE); /* * If we're in the process of opening the pool, dp will not be * set yet, but there shouldn't be anything dirty. */ if (dp == NULL) return (FALSE); if (dn->dn_free_txg) return (TRUE); if (blkid == DMU_SPILL_BLKID) return (dnode_spill_freed(dn)); mutex_enter(&dn->dn_mtx); for (i = 0; i < TXG_SIZE; i++) { if (dn->dn_free_ranges[i] != NULL && range_tree_contains(dn->dn_free_ranges[i], blkid, 1)) break; } mutex_exit(&dn->dn_mtx); return (i < TXG_SIZE); } /* call from syncing context when we actually write/free space for this dnode */ void dnode_diduse_space(dnode_t *dn, int64_t delta) { uint64_t space; dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n", dn, dn->dn_phys, (u_longlong_t)dn->dn_phys->dn_used, (longlong_t)delta); mutex_enter(&dn->dn_mtx); space = DN_USED_BYTES(dn->dn_phys); if (delta > 0) { ASSERT3U(space + delta, >=, space); /* no overflow */ } else { ASSERT3U(space, >=, -delta); /* no underflow */ } space += delta; if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) { ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0); ASSERT0(P2PHASE(space, 1<dn_phys->dn_used = space >> DEV_BSHIFT; } else { dn->dn_phys->dn_used = space; dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES; } mutex_exit(&dn->dn_mtx); } /* * Scans a block at the indicated "level" looking for a hole or data, * depending on 'flags'. * * If level > 0, then we are scanning an indirect block looking at its * pointers. If level == 0, then we are looking at a block of dnodes. * * If we don't find what we are looking for in the block, we return ESRCH. * Otherwise, return with *offset pointing to the beginning (if searching * forwards) or end (if searching backwards) of the range covered by the * block pointer we matched on (or dnode). * * The basic search algorithm used below by dnode_next_offset() is to * use this function to search up the block tree (widen the search) until * we find something (i.e., we don't return ESRCH) and then search back * down the tree (narrow the search) until we reach our original search * level. */ static int dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset, int lvl, uint64_t blkfill, uint64_t txg) { dmu_buf_impl_t *db = NULL; void *data = NULL; uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT; uint64_t epb = 1ULL << epbs; uint64_t minfill, maxfill; boolean_t hole; int i, inc, error, span; ASSERT(RW_LOCK_HELD(&dn->dn_struct_rwlock)); hole = ((flags & DNODE_FIND_HOLE) != 0); inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1; ASSERT(txg == 0 || !hole); if (lvl == dn->dn_phys->dn_nlevels) { error = 0; epb = dn->dn_phys->dn_nblkptr; data = dn->dn_phys->dn_blkptr; } else { uint64_t blkid = dbuf_whichblock(dn, lvl, *offset); error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FALSE, FTAG, &db); if (error) { if (error != ENOENT) return (error); if (hole) return (0); /* * This can only happen when we are searching up * the block tree for data. We don't really need to * adjust the offset, as we will just end up looking * at the pointer to this block in its parent, and its * going to be unallocated, so we will skip over it. */ return (SET_ERROR(ESRCH)); } error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT | DB_RF_NO_DECRYPT | DB_RF_NOPREFETCH); if (error) { dbuf_rele(db, FTAG); return (error); } data = db->db.db_data; rw_enter(&db->db_rwlock, RW_READER); } if (db != NULL && txg != 0 && (db->db_blkptr == NULL || db->db_blkptr->blk_birth <= txg || BP_IS_HOLE(db->db_blkptr))) { /* * This can only happen when we are searching up the tree * and these conditions mean that we need to keep climbing. */ error = SET_ERROR(ESRCH); } else if (lvl == 0) { dnode_phys_t *dnp = data; ASSERT(dn->dn_type == DMU_OT_DNODE); ASSERT(!(flags & DNODE_FIND_BACKWARDS)); for (i = (*offset >> DNODE_SHIFT) & (blkfill - 1); i < blkfill; i += dnp[i].dn_extra_slots + 1) { if ((dnp[i].dn_type == DMU_OT_NONE) == hole) break; } if (i == blkfill) error = SET_ERROR(ESRCH); *offset = (*offset & ~(DNODE_BLOCK_SIZE - 1)) + (i << DNODE_SHIFT); } else { blkptr_t *bp = data; uint64_t start = *offset; span = (lvl - 1) * epbs + dn->dn_datablkshift; minfill = 0; maxfill = blkfill << ((lvl - 1) * epbs); if (hole) maxfill--; else minfill++; if (span >= 8 * sizeof (*offset)) { /* This only happens on the highest indirection level */ ASSERT3U((lvl - 1), ==, dn->dn_phys->dn_nlevels - 1); *offset = 0; } else { *offset = *offset >> span; } for (i = BF64_GET(*offset, 0, epbs); i >= 0 && i < epb; i += inc) { if (BP_GET_FILL(&bp[i]) >= minfill && BP_GET_FILL(&bp[i]) <= maxfill && (hole || bp[i].blk_birth > txg)) break; if (inc > 0 || *offset > 0) *offset += inc; } if (span >= 8 * sizeof (*offset)) { *offset = start; } else { *offset = *offset << span; } if (inc < 0) { /* traversing backwards; position offset at the end */ ASSERT3U(*offset, <=, start); *offset = MIN(*offset + (1ULL << span) - 1, start); } else if (*offset < start) { *offset = start; } if (i < 0 || i >= epb) error = SET_ERROR(ESRCH); } if (db != NULL) { rw_exit(&db->db_rwlock); dbuf_rele(db, FTAG); } return (error); } /* * Find the next hole, data, or sparse region at or after *offset. * The value 'blkfill' tells us how many items we expect to find * in an L0 data block; this value is 1 for normal objects, * DNODES_PER_BLOCK for the meta dnode, and some fraction of * DNODES_PER_BLOCK when searching for sparse regions thereof. * * Examples: * * dnode_next_offset(dn, flags, offset, 1, 1, 0); * Finds the next/previous hole/data in a file. * Used in dmu_offset_next(). * * dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg); * Finds the next free/allocated dnode an objset's meta-dnode. * Only finds objects that have new contents since txg (ie. * bonus buffer changes and content removal are ignored). * Used in dmu_object_next(). * * dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0); * Finds the next L2 meta-dnode bp that's at most 1/4 full. * Used in dmu_object_alloc(). */ int dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset, int minlvl, uint64_t blkfill, uint64_t txg) { uint64_t initial_offset = *offset; int lvl, maxlvl; int error = 0; if (!(flags & DNODE_FIND_HAVELOCK)) rw_enter(&dn->dn_struct_rwlock, RW_READER); if (dn->dn_phys->dn_nlevels == 0) { error = SET_ERROR(ESRCH); goto out; } if (dn->dn_datablkshift == 0) { if (*offset < dn->dn_datablksz) { if (flags & DNODE_FIND_HOLE) *offset = dn->dn_datablksz; } else { error = SET_ERROR(ESRCH); } goto out; } maxlvl = dn->dn_phys->dn_nlevels; for (lvl = minlvl; lvl <= maxlvl; lvl++) { error = dnode_next_offset_level(dn, flags, offset, lvl, blkfill, txg); if (error != ESRCH) break; } while (error == 0 && --lvl >= minlvl) { error = dnode_next_offset_level(dn, flags, offset, lvl, blkfill, txg); } /* * There's always a "virtual hole" at the end of the object, even * if all BP's which physically exist are non-holes. */ if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 && minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) { error = 0; } if (error == 0 && (flags & DNODE_FIND_BACKWARDS ? initial_offset < *offset : initial_offset > *offset)) error = SET_ERROR(ESRCH); out: if (!(flags & DNODE_FIND_HAVELOCK)) rw_exit(&dn->dn_struct_rwlock); return (error); } #if defined(_KERNEL) EXPORT_SYMBOL(dnode_hold); EXPORT_SYMBOL(dnode_rele); EXPORT_SYMBOL(dnode_set_nlevels); EXPORT_SYMBOL(dnode_set_blksz); EXPORT_SYMBOL(dnode_free_range); EXPORT_SYMBOL(dnode_evict_dbufs); EXPORT_SYMBOL(dnode_evict_bonus); #endif diff --git a/module/zfs/fm.c b/module/zfs/fm.c index e7a7ad583242..bc13b5517c4e 100644 --- a/module/zfs/fm.c +++ b/module/zfs/fm.c @@ -1,1374 +1,1374 @@ /* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or https://opensource.org/licenses/CDDL-1.0. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved. */ /* * Fault Management Architecture (FMA) Resource and Protocol Support * * The routines contained herein provide services to support kernel subsystems * in publishing fault management telemetry (see PSARC 2002/412 and 2003/089). * * Name-Value Pair Lists * * The embodiment of an FMA protocol element (event, fmri or authority) is a * name-value pair list (nvlist_t). FMA-specific nvlist constructor and * destructor functions, fm_nvlist_create() and fm_nvlist_destroy(), are used * to create an nvpair list using custom allocators. Callers may choose to * allocate either from the kernel memory allocator, or from a preallocated * buffer, useful in constrained contexts like high-level interrupt routines. * * Protocol Event and FMRI Construction * * Convenience routines are provided to construct nvlist events according to * the FMA Event Protocol and Naming Schema specification for ereports and * FMRIs for the dev, cpu, hc, mem, legacy hc and de schemes. * * ENA Manipulation * * Routines to generate ENA formats 0, 1 and 2 are available as well as * routines to increment formats 1 and 2. Individual fields within the * ENA are extractable via fm_ena_time_get(), fm_ena_id_get(), * fm_ena_format_get() and fm_ena_gen_get(). */ #include #include #include #include #include #include #include #include #include #include #include #include #ifdef _KERNEL #include #include #include static int zfs_zevent_len_max = 512; static int zevent_len_cur = 0; static int zevent_waiters = 0; static int zevent_flags = 0; /* Num events rate limited since the last time zfs_zevent_next() was called */ static uint64_t ratelimit_dropped = 0; /* * The EID (Event IDentifier) is used to uniquely tag a zevent when it is * posted. The posted EIDs are monotonically increasing but not persistent. * They will be reset to the initial value (1) each time the kernel module is * loaded. */ static uint64_t zevent_eid = 0; static kmutex_t zevent_lock; static list_t zevent_list; static kcondvar_t zevent_cv; #endif /* _KERNEL */ /* * Common fault management kstats to record event generation failures */ struct erpt_kstat { kstat_named_t erpt_dropped; /* num erpts dropped on post */ kstat_named_t erpt_set_failed; /* num erpt set failures */ kstat_named_t fmri_set_failed; /* num fmri set failures */ kstat_named_t payload_set_failed; /* num payload set failures */ kstat_named_t erpt_duplicates; /* num duplicate erpts */ }; static struct erpt_kstat erpt_kstat_data = { { "erpt-dropped", KSTAT_DATA_UINT64 }, { "erpt-set-failed", KSTAT_DATA_UINT64 }, { "fmri-set-failed", KSTAT_DATA_UINT64 }, { "payload-set-failed", KSTAT_DATA_UINT64 }, { "erpt-duplicates", KSTAT_DATA_UINT64 } }; kstat_t *fm_ksp; #ifdef _KERNEL static zevent_t * zfs_zevent_alloc(void) { zevent_t *ev; ev = kmem_zalloc(sizeof (zevent_t), KM_SLEEP); list_create(&ev->ev_ze_list, sizeof (zfs_zevent_t), offsetof(zfs_zevent_t, ze_node)); list_link_init(&ev->ev_node); return (ev); } static void zfs_zevent_free(zevent_t *ev) { /* Run provided cleanup callback */ ev->ev_cb(ev->ev_nvl, ev->ev_detector); list_destroy(&ev->ev_ze_list); kmem_free(ev, sizeof (zevent_t)); } static void zfs_zevent_drain(zevent_t *ev) { zfs_zevent_t *ze; ASSERT(MUTEX_HELD(&zevent_lock)); list_remove(&zevent_list, ev); /* Remove references to this event in all private file data */ while ((ze = list_head(&ev->ev_ze_list)) != NULL) { list_remove(&ev->ev_ze_list, ze); ze->ze_zevent = NULL; ze->ze_dropped++; } zfs_zevent_free(ev); } void zfs_zevent_drain_all(int *count) { zevent_t *ev; mutex_enter(&zevent_lock); while ((ev = list_head(&zevent_list)) != NULL) zfs_zevent_drain(ev); *count = zevent_len_cur; zevent_len_cur = 0; mutex_exit(&zevent_lock); } /* * New zevents are inserted at the head. If the maximum queue * length is exceeded a zevent will be drained from the tail. * As part of this any user space processes which currently have * a reference to this zevent_t in their private data will have * this reference set to NULL. */ static void zfs_zevent_insert(zevent_t *ev) { ASSERT(MUTEX_HELD(&zevent_lock)); list_insert_head(&zevent_list, ev); if (zevent_len_cur >= zfs_zevent_len_max) zfs_zevent_drain(list_tail(&zevent_list)); else zevent_len_cur++; } /* * Post a zevent. The cb will be called when nvl and detector are no longer * needed, i.e.: * - An error happened and a zevent can't be posted. In this case, cb is called * before zfs_zevent_post() returns. * - The event is being drained and freed. */ int zfs_zevent_post(nvlist_t *nvl, nvlist_t *detector, zevent_cb_t *cb) { inode_timespec_t tv; int64_t tv_array[2]; uint64_t eid; size_t nvl_size = 0; zevent_t *ev; int error; ASSERT(cb != NULL); gethrestime(&tv); tv_array[0] = tv.tv_sec; tv_array[1] = tv.tv_nsec; error = nvlist_add_int64_array(nvl, FM_EREPORT_TIME, tv_array, 2); if (error) { atomic_inc_64(&erpt_kstat_data.erpt_set_failed.value.ui64); goto out; } eid = atomic_inc_64_nv(&zevent_eid); error = nvlist_add_uint64(nvl, FM_EREPORT_EID, eid); if (error) { atomic_inc_64(&erpt_kstat_data.erpt_set_failed.value.ui64); goto out; } error = nvlist_size(nvl, &nvl_size, NV_ENCODE_NATIVE); if (error) { atomic_inc_64(&erpt_kstat_data.erpt_dropped.value.ui64); goto out; } if (nvl_size > ERPT_DATA_SZ || nvl_size == 0) { atomic_inc_64(&erpt_kstat_data.erpt_dropped.value.ui64); error = EOVERFLOW; goto out; } ev = zfs_zevent_alloc(); if (ev == NULL) { atomic_inc_64(&erpt_kstat_data.erpt_dropped.value.ui64); error = ENOMEM; goto out; } ev->ev_nvl = nvl; ev->ev_detector = detector; ev->ev_cb = cb; ev->ev_eid = eid; mutex_enter(&zevent_lock); zfs_zevent_insert(ev); cv_broadcast(&zevent_cv); mutex_exit(&zevent_lock); out: if (error) cb(nvl, detector); return (error); } void zfs_zevent_track_duplicate(void) { atomic_inc_64(&erpt_kstat_data.erpt_duplicates.value.ui64); } static int zfs_zevent_minor_to_state(minor_t minor, zfs_zevent_t **ze) { *ze = zfsdev_get_state(minor, ZST_ZEVENT); if (*ze == NULL) return (SET_ERROR(EBADF)); return (0); } zfs_file_t * zfs_zevent_fd_hold(int fd, minor_t *minorp, zfs_zevent_t **ze) { zfs_file_t *fp = zfs_file_get(fd); if (fp == NULL) return (NULL); int error = zfsdev_getminor(fp, minorp); if (error == 0) error = zfs_zevent_minor_to_state(*minorp, ze); if (error) { zfs_zevent_fd_rele(fp); fp = NULL; } return (fp); } void zfs_zevent_fd_rele(zfs_file_t *fp) { zfs_file_put(fp); } /* * Get the next zevent in the stream and place a copy in 'event'. This * may fail with ENOMEM if the encoded nvlist size exceeds the passed * 'event_size'. In this case the stream pointer is not advanced and * and 'event_size' is set to the minimum required buffer size. */ int zfs_zevent_next(zfs_zevent_t *ze, nvlist_t **event, uint64_t *event_size, uint64_t *dropped) { zevent_t *ev; size_t size; int error = 0; mutex_enter(&zevent_lock); if (ze->ze_zevent == NULL) { /* New stream start at the beginning/tail */ ev = list_tail(&zevent_list); if (ev == NULL) { error = ENOENT; goto out; } } else { /* * Existing stream continue with the next element and remove * ourselves from the wait queue for the previous element */ ev = list_prev(&zevent_list, ze->ze_zevent); if (ev == NULL) { error = ENOENT; goto out; } } VERIFY(nvlist_size(ev->ev_nvl, &size, NV_ENCODE_NATIVE) == 0); if (size > *event_size) { *event_size = size; error = ENOMEM; goto out; } if (ze->ze_zevent) list_remove(&ze->ze_zevent->ev_ze_list, ze); ze->ze_zevent = ev; list_insert_head(&ev->ev_ze_list, ze); (void) nvlist_dup(ev->ev_nvl, event, KM_SLEEP); *dropped = ze->ze_dropped; #ifdef _KERNEL /* Include events dropped due to rate limiting */ *dropped += atomic_swap_64(&ratelimit_dropped, 0); #endif ze->ze_dropped = 0; out: mutex_exit(&zevent_lock); return (error); } /* * Wait in an interruptible state for any new events. */ int zfs_zevent_wait(zfs_zevent_t *ze) { int error = EAGAIN; mutex_enter(&zevent_lock); zevent_waiters++; while (error == EAGAIN) { if (zevent_flags & ZEVENT_SHUTDOWN) { error = SET_ERROR(ESHUTDOWN); break; } error = cv_wait_sig(&zevent_cv, &zevent_lock); if (signal_pending(current)) { error = SET_ERROR(EINTR); break; } else if (!list_is_empty(&zevent_list)) { error = 0; continue; } else { error = EAGAIN; } } zevent_waiters--; mutex_exit(&zevent_lock); return (error); } /* * The caller may seek to a specific EID by passing that EID. If the EID * is still available in the posted list of events the cursor is positioned * there. Otherwise ENOENT is returned and the cursor is not moved. * * There are two reserved EIDs which may be passed and will never fail. * ZEVENT_SEEK_START positions the cursor at the start of the list, and * ZEVENT_SEEK_END positions the cursor at the end of the list. */ int zfs_zevent_seek(zfs_zevent_t *ze, uint64_t eid) { zevent_t *ev; int error = 0; mutex_enter(&zevent_lock); if (eid == ZEVENT_SEEK_START) { if (ze->ze_zevent) list_remove(&ze->ze_zevent->ev_ze_list, ze); ze->ze_zevent = NULL; goto out; } if (eid == ZEVENT_SEEK_END) { if (ze->ze_zevent) list_remove(&ze->ze_zevent->ev_ze_list, ze); ev = list_head(&zevent_list); if (ev) { ze->ze_zevent = ev; list_insert_head(&ev->ev_ze_list, ze); } else { ze->ze_zevent = NULL; } goto out; } for (ev = list_tail(&zevent_list); ev != NULL; ev = list_prev(&zevent_list, ev)) { if (ev->ev_eid == eid) { if (ze->ze_zevent) list_remove(&ze->ze_zevent->ev_ze_list, ze); ze->ze_zevent = ev; list_insert_head(&ev->ev_ze_list, ze); break; } } if (ev == NULL) error = ENOENT; out: mutex_exit(&zevent_lock); return (error); } void zfs_zevent_init(zfs_zevent_t **zep) { zfs_zevent_t *ze; ze = *zep = kmem_zalloc(sizeof (zfs_zevent_t), KM_SLEEP); list_link_init(&ze->ze_node); } void zfs_zevent_destroy(zfs_zevent_t *ze) { mutex_enter(&zevent_lock); if (ze->ze_zevent) list_remove(&ze->ze_zevent->ev_ze_list, ze); mutex_exit(&zevent_lock); kmem_free(ze, sizeof (zfs_zevent_t)); } #endif /* _KERNEL */ /* * Wrappers for FM nvlist allocators */ static void * i_fm_alloc(nv_alloc_t *nva, size_t size) { (void) nva; return (kmem_alloc(size, KM_SLEEP)); } static void i_fm_free(nv_alloc_t *nva, void *buf, size_t size) { (void) nva; kmem_free(buf, size); } static const nv_alloc_ops_t fm_mem_alloc_ops = { .nv_ao_init = NULL, .nv_ao_fini = NULL, .nv_ao_alloc = i_fm_alloc, .nv_ao_free = i_fm_free, .nv_ao_reset = NULL }; /* * Create and initialize a new nv_alloc_t for a fixed buffer, buf. A pointer * to the newly allocated nv_alloc_t structure is returned upon success or NULL * is returned to indicate that the nv_alloc structure could not be created. */ nv_alloc_t * fm_nva_xcreate(char *buf, size_t bufsz) { nv_alloc_t *nvhdl = kmem_zalloc(sizeof (nv_alloc_t), KM_SLEEP); if (bufsz == 0 || nv_alloc_init(nvhdl, nv_fixed_ops, buf, bufsz) != 0) { kmem_free(nvhdl, sizeof (nv_alloc_t)); return (NULL); } return (nvhdl); } /* * Destroy a previously allocated nv_alloc structure. The fixed buffer * associated with nva must be freed by the caller. */ void fm_nva_xdestroy(nv_alloc_t *nva) { nv_alloc_fini(nva); kmem_free(nva, sizeof (nv_alloc_t)); } /* * Create a new nv list. A pointer to a new nv list structure is returned * upon success or NULL is returned to indicate that the structure could * not be created. The newly created nv list is created and managed by the * operations installed in nva. If nva is NULL, the default FMA nva * operations are installed and used. * * When called from the kernel and nva == NULL, this function must be called * from passive kernel context with no locks held that can prevent a * sleeping memory allocation from occurring. Otherwise, this function may * be called from other kernel contexts as long a valid nva created via * fm_nva_create() is supplied. */ nvlist_t * fm_nvlist_create(nv_alloc_t *nva) { int hdl_alloced = 0; nvlist_t *nvl; nv_alloc_t *nvhdl; if (nva == NULL) { nvhdl = kmem_zalloc(sizeof (nv_alloc_t), KM_SLEEP); if (nv_alloc_init(nvhdl, &fm_mem_alloc_ops, NULL, 0) != 0) { kmem_free(nvhdl, sizeof (nv_alloc_t)); return (NULL); } hdl_alloced = 1; } else { nvhdl = nva; } if (nvlist_xalloc(&nvl, NV_UNIQUE_NAME, nvhdl) != 0) { if (hdl_alloced) { nv_alloc_fini(nvhdl); kmem_free(nvhdl, sizeof (nv_alloc_t)); } return (NULL); } return (nvl); } /* * Destroy a previously allocated nvlist structure. flag indicates whether * or not the associated nva structure should be freed (FM_NVA_FREE) or * retained (FM_NVA_RETAIN). Retaining the nv alloc structure allows * it to be re-used for future nvlist creation operations. */ void fm_nvlist_destroy(nvlist_t *nvl, int flag) { nv_alloc_t *nva = nvlist_lookup_nv_alloc(nvl); nvlist_free(nvl); if (nva != NULL) { if (flag == FM_NVA_FREE) fm_nva_xdestroy(nva); } } int i_fm_payload_set(nvlist_t *payload, const char *name, va_list ap) { int nelem, ret = 0; data_type_t type; while (ret == 0 && name != NULL) { type = va_arg(ap, data_type_t); switch (type) { case DATA_TYPE_BYTE: ret = nvlist_add_byte(payload, name, va_arg(ap, uint_t)); break; case DATA_TYPE_BYTE_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_byte_array(payload, name, va_arg(ap, uchar_t *), nelem); break; case DATA_TYPE_BOOLEAN_VALUE: ret = nvlist_add_boolean_value(payload, name, va_arg(ap, boolean_t)); break; case DATA_TYPE_BOOLEAN_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_boolean_array(payload, name, va_arg(ap, boolean_t *), nelem); break; case DATA_TYPE_INT8: ret = nvlist_add_int8(payload, name, va_arg(ap, int)); break; case DATA_TYPE_INT8_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_int8_array(payload, name, va_arg(ap, int8_t *), nelem); break; case DATA_TYPE_UINT8: ret = nvlist_add_uint8(payload, name, va_arg(ap, uint_t)); break; case DATA_TYPE_UINT8_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_uint8_array(payload, name, va_arg(ap, uint8_t *), nelem); break; case DATA_TYPE_INT16: ret = nvlist_add_int16(payload, name, va_arg(ap, int)); break; case DATA_TYPE_INT16_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_int16_array(payload, name, va_arg(ap, int16_t *), nelem); break; case DATA_TYPE_UINT16: ret = nvlist_add_uint16(payload, name, va_arg(ap, uint_t)); break; case DATA_TYPE_UINT16_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_uint16_array(payload, name, va_arg(ap, uint16_t *), nelem); break; case DATA_TYPE_INT32: ret = nvlist_add_int32(payload, name, va_arg(ap, int32_t)); break; case DATA_TYPE_INT32_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_int32_array(payload, name, va_arg(ap, int32_t *), nelem); break; case DATA_TYPE_UINT32: ret = nvlist_add_uint32(payload, name, va_arg(ap, uint32_t)); break; case DATA_TYPE_UINT32_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_uint32_array(payload, name, va_arg(ap, uint32_t *), nelem); break; case DATA_TYPE_INT64: ret = nvlist_add_int64(payload, name, va_arg(ap, int64_t)); break; case DATA_TYPE_INT64_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_int64_array(payload, name, va_arg(ap, int64_t *), nelem); break; case DATA_TYPE_UINT64: ret = nvlist_add_uint64(payload, name, va_arg(ap, uint64_t)); break; case DATA_TYPE_UINT64_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_uint64_array(payload, name, va_arg(ap, uint64_t *), nelem); break; case DATA_TYPE_STRING: ret = nvlist_add_string(payload, name, va_arg(ap, char *)); break; case DATA_TYPE_STRING_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_string_array(payload, name, va_arg(ap, const char **), nelem); break; case DATA_TYPE_NVLIST: ret = nvlist_add_nvlist(payload, name, va_arg(ap, nvlist_t *)); break; case DATA_TYPE_NVLIST_ARRAY: nelem = va_arg(ap, int); ret = nvlist_add_nvlist_array(payload, name, va_arg(ap, const nvlist_t **), nelem); break; default: ret = EINVAL; } name = va_arg(ap, char *); } return (ret); } void fm_payload_set(nvlist_t *payload, ...) { int ret; const char *name; va_list ap; va_start(ap, payload); name = va_arg(ap, char *); ret = i_fm_payload_set(payload, name, ap); va_end(ap); if (ret) atomic_inc_64(&erpt_kstat_data.payload_set_failed.value.ui64); } /* * Set-up and validate the members of an ereport event according to: * * Member name Type Value * ==================================================== * class string ereport * version uint8_t 0 * ena uint64_t * detector nvlist_t * ereport-payload nvlist_t * * We don't actually add a 'version' member to the payload. Really, * the version quoted to us by our caller is that of the category 1 * "ereport" event class (and we require FM_EREPORT_VERS0) but * the payload version of the actual leaf class event under construction * may be something else. Callers should supply a version in the varargs, * or (better) we could take two version arguments - one for the * ereport category 1 classification (expect FM_EREPORT_VERS0) and one * for the leaf class. */ void fm_ereport_set(nvlist_t *ereport, int version, const char *erpt_class, uint64_t ena, const nvlist_t *detector, ...) { char ereport_class[FM_MAX_CLASS]; const char *name; va_list ap; int ret; if (version != FM_EREPORT_VERS0) { atomic_inc_64(&erpt_kstat_data.erpt_set_failed.value.ui64); return; } (void) snprintf(ereport_class, FM_MAX_CLASS, "%s.%s", FM_EREPORT_CLASS, erpt_class); if (nvlist_add_string(ereport, FM_CLASS, ereport_class) != 0) { atomic_inc_64(&erpt_kstat_data.erpt_set_failed.value.ui64); return; } if (nvlist_add_uint64(ereport, FM_EREPORT_ENA, ena)) { atomic_inc_64(&erpt_kstat_data.erpt_set_failed.value.ui64); } if (nvlist_add_nvlist(ereport, FM_EREPORT_DETECTOR, (nvlist_t *)detector) != 0) { atomic_inc_64(&erpt_kstat_data.erpt_set_failed.value.ui64); } va_start(ap, detector); name = va_arg(ap, const char *); ret = i_fm_payload_set(ereport, name, ap); va_end(ap); if (ret) atomic_inc_64(&erpt_kstat_data.erpt_set_failed.value.ui64); } /* * Set-up and validate the members of an hc fmri according to; * * Member name Type Value * =================================================== * version uint8_t 0 * auth nvlist_t * hc-name string * hc-id string * * Note that auth and hc-id are optional members. */ #define HC_MAXPAIRS 20 #define HC_MAXNAMELEN 50 static int fm_fmri_hc_set_common(nvlist_t *fmri, int version, const nvlist_t *auth) { if (version != FM_HC_SCHEME_VERSION) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return (0); } if (nvlist_add_uint8(fmri, FM_VERSION, version) != 0 || nvlist_add_string(fmri, FM_FMRI_SCHEME, FM_FMRI_SCHEME_HC) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return (0); } if (auth != NULL && nvlist_add_nvlist(fmri, FM_FMRI_AUTHORITY, (nvlist_t *)auth) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return (0); } return (1); } void fm_fmri_hc_set(nvlist_t *fmri, int version, const nvlist_t *auth, nvlist_t *snvl, int npairs, ...) { nv_alloc_t *nva = nvlist_lookup_nv_alloc(fmri); nvlist_t *pairs[HC_MAXPAIRS]; va_list ap; int i; if (!fm_fmri_hc_set_common(fmri, version, auth)) return; npairs = MIN(npairs, HC_MAXPAIRS); va_start(ap, npairs); for (i = 0; i < npairs; i++) { const char *name = va_arg(ap, const char *); uint32_t id = va_arg(ap, uint32_t); char idstr[11]; (void) snprintf(idstr, sizeof (idstr), "%u", id); pairs[i] = fm_nvlist_create(nva); if (nvlist_add_string(pairs[i], FM_FMRI_HC_NAME, name) != 0 || nvlist_add_string(pairs[i], FM_FMRI_HC_ID, idstr) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); } } va_end(ap); if (nvlist_add_nvlist_array(fmri, FM_FMRI_HC_LIST, (const nvlist_t **)pairs, npairs) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); } for (i = 0; i < npairs; i++) fm_nvlist_destroy(pairs[i], FM_NVA_RETAIN); if (snvl != NULL) { if (nvlist_add_nvlist(fmri, FM_FMRI_HC_SPECIFIC, snvl) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); } } } void fm_fmri_hc_create(nvlist_t *fmri, int version, const nvlist_t *auth, nvlist_t *snvl, nvlist_t *bboard, int npairs, ...) { nv_alloc_t *nva = nvlist_lookup_nv_alloc(fmri); nvlist_t *pairs[HC_MAXPAIRS]; nvlist_t **hcl; uint_t n; int i, j; va_list ap; char *hcname, *hcid; if (!fm_fmri_hc_set_common(fmri, version, auth)) return; /* * copy the bboard nvpairs to the pairs array */ if (nvlist_lookup_nvlist_array(bboard, FM_FMRI_HC_LIST, &hcl, &n) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } for (i = 0; i < n; i++) { if (nvlist_lookup_string(hcl[i], FM_FMRI_HC_NAME, &hcname) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (nvlist_lookup_string(hcl[i], FM_FMRI_HC_ID, &hcid) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); return; } pairs[i] = fm_nvlist_create(nva); if (nvlist_add_string(pairs[i], FM_FMRI_HC_NAME, hcname) != 0 || nvlist_add_string(pairs[i], FM_FMRI_HC_ID, hcid) != 0) { for (j = 0; j <= i; j++) { if (pairs[j] != NULL) fm_nvlist_destroy(pairs[j], FM_NVA_RETAIN); } atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); return; } } /* * create the pairs from passed in pairs */ npairs = MIN(npairs, HC_MAXPAIRS); va_start(ap, npairs); for (i = n; i < npairs + n; i++) { const char *name = va_arg(ap, const char *); uint32_t id = va_arg(ap, uint32_t); char idstr[11]; (void) snprintf(idstr, sizeof (idstr), "%u", id); pairs[i] = fm_nvlist_create(nva); if (nvlist_add_string(pairs[i], FM_FMRI_HC_NAME, name) != 0 || nvlist_add_string(pairs[i], FM_FMRI_HC_ID, idstr) != 0) { for (j = 0; j <= i; j++) { if (pairs[j] != NULL) fm_nvlist_destroy(pairs[j], FM_NVA_RETAIN); } atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); return; } } va_end(ap); /* * Create the fmri hc list */ if (nvlist_add_nvlist_array(fmri, FM_FMRI_HC_LIST, (const nvlist_t **)pairs, npairs + n) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } for (i = 0; i < npairs + n; i++) { fm_nvlist_destroy(pairs[i], FM_NVA_RETAIN); } if (snvl != NULL) { if (nvlist_add_nvlist(fmri, FM_FMRI_HC_SPECIFIC, snvl) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); return; } } } /* * Set-up and validate the members of an dev fmri according to: * * Member name Type Value * ==================================================== * version uint8_t 0 * auth nvlist_t * devpath string * [devid] string * [target-port-l0id] string * * Note that auth and devid are optional members. */ void fm_fmri_dev_set(nvlist_t *fmri_dev, int version, const nvlist_t *auth, const char *devpath, const char *devid, const char *tpl0) { int err = 0; if (version != DEV_SCHEME_VERSION0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } err |= nvlist_add_uint8(fmri_dev, FM_VERSION, version); err |= nvlist_add_string(fmri_dev, FM_FMRI_SCHEME, FM_FMRI_SCHEME_DEV); if (auth != NULL) { err |= nvlist_add_nvlist(fmri_dev, FM_FMRI_AUTHORITY, (nvlist_t *)auth); } err |= nvlist_add_string(fmri_dev, FM_FMRI_DEV_PATH, devpath); if (devid != NULL) err |= nvlist_add_string(fmri_dev, FM_FMRI_DEV_ID, devid); if (tpl0 != NULL) err |= nvlist_add_string(fmri_dev, FM_FMRI_DEV_TGTPTLUN0, tpl0); if (err) atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); } /* * Set-up and validate the members of an cpu fmri according to: * * Member name Type Value * ==================================================== * version uint8_t 0 * auth nvlist_t * cpuid uint32_t * cpumask uint8_t * serial uint64_t * * Note that auth, cpumask, serial are optional members. * */ void fm_fmri_cpu_set(nvlist_t *fmri_cpu, int version, const nvlist_t *auth, uint32_t cpu_id, uint8_t *cpu_maskp, const char *serial_idp) { uint64_t *failedp = &erpt_kstat_data.fmri_set_failed.value.ui64; if (version < CPU_SCHEME_VERSION1) { atomic_inc_64(failedp); return; } if (nvlist_add_uint8(fmri_cpu, FM_VERSION, version) != 0) { atomic_inc_64(failedp); return; } if (nvlist_add_string(fmri_cpu, FM_FMRI_SCHEME, FM_FMRI_SCHEME_CPU) != 0) { atomic_inc_64(failedp); return; } if (auth != NULL && nvlist_add_nvlist(fmri_cpu, FM_FMRI_AUTHORITY, (nvlist_t *)auth) != 0) atomic_inc_64(failedp); if (nvlist_add_uint32(fmri_cpu, FM_FMRI_CPU_ID, cpu_id) != 0) atomic_inc_64(failedp); if (cpu_maskp != NULL && nvlist_add_uint8(fmri_cpu, FM_FMRI_CPU_MASK, *cpu_maskp) != 0) atomic_inc_64(failedp); if (serial_idp == NULL || nvlist_add_string(fmri_cpu, FM_FMRI_CPU_SERIAL_ID, (char *)serial_idp) != 0) atomic_inc_64(failedp); } /* * Set-up and validate the members of a mem according to: * * Member name Type Value * ==================================================== * version uint8_t 0 * auth nvlist_t [optional] * unum string * serial string [optional*] * offset uint64_t [optional] * * * serial is required if offset is present */ void fm_fmri_mem_set(nvlist_t *fmri, int version, const nvlist_t *auth, const char *unum, const char *serial, uint64_t offset) { if (version != MEM_SCHEME_VERSION0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (!serial && (offset != (uint64_t)-1)) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (nvlist_add_uint8(fmri, FM_VERSION, version) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (nvlist_add_string(fmri, FM_FMRI_SCHEME, FM_FMRI_SCHEME_MEM) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (auth != NULL) { if (nvlist_add_nvlist(fmri, FM_FMRI_AUTHORITY, (nvlist_t *)auth) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); } } if (nvlist_add_string(fmri, FM_FMRI_MEM_UNUM, unum) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); } if (serial != NULL) { if (nvlist_add_string_array(fmri, FM_FMRI_MEM_SERIAL_ID, (const char **)&serial, 1) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); } if (offset != (uint64_t)-1 && nvlist_add_uint64(fmri, FM_FMRI_MEM_OFFSET, offset) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); } } } void fm_fmri_zfs_set(nvlist_t *fmri, int version, uint64_t pool_guid, uint64_t vdev_guid) { if (version != ZFS_SCHEME_VERSION0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (nvlist_add_uint8(fmri, FM_VERSION, version) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (nvlist_add_string(fmri, FM_FMRI_SCHEME, FM_FMRI_SCHEME_ZFS) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); return; } if (nvlist_add_uint64(fmri, FM_FMRI_ZFS_POOL, pool_guid) != 0) { atomic_inc_64(&erpt_kstat_data.fmri_set_failed.value.ui64); } if (vdev_guid != 0) { if (nvlist_add_uint64(fmri, FM_FMRI_ZFS_VDEV, vdev_guid) != 0) { atomic_inc_64( &erpt_kstat_data.fmri_set_failed.value.ui64); } } } uint64_t fm_ena_increment(uint64_t ena) { uint64_t new_ena; switch (ENA_FORMAT(ena)) { case FM_ENA_FMT1: new_ena = ena + (1 << ENA_FMT1_GEN_SHFT); break; case FM_ENA_FMT2: new_ena = ena + (1 << ENA_FMT2_GEN_SHFT); break; default: new_ena = 0; } return (new_ena); } uint64_t fm_ena_generate_cpu(uint64_t timestamp, processorid_t cpuid, uchar_t format) { uint64_t ena = 0; switch (format) { case FM_ENA_FMT1: if (timestamp) { ena = (uint64_t)((format & ENA_FORMAT_MASK) | ((cpuid << ENA_FMT1_CPUID_SHFT) & ENA_FMT1_CPUID_MASK) | ((timestamp << ENA_FMT1_TIME_SHFT) & ENA_FMT1_TIME_MASK)); } else { ena = (uint64_t)((format & ENA_FORMAT_MASK) | ((cpuid << ENA_FMT1_CPUID_SHFT) & ENA_FMT1_CPUID_MASK) | ((gethrtime() << ENA_FMT1_TIME_SHFT) & ENA_FMT1_TIME_MASK)); } break; case FM_ENA_FMT2: ena = (uint64_t)((format & ENA_FORMAT_MASK) | ((timestamp << ENA_FMT2_TIME_SHFT) & ENA_FMT2_TIME_MASK)); break; default: break; } return (ena); } uint64_t fm_ena_generate(uint64_t timestamp, uchar_t format) { uint64_t ena; kpreempt_disable(); ena = fm_ena_generate_cpu(timestamp, getcpuid(), format); kpreempt_enable(); return (ena); } uint64_t fm_ena_generation_get(uint64_t ena) { uint64_t gen; switch (ENA_FORMAT(ena)) { case FM_ENA_FMT1: gen = (ena & ENA_FMT1_GEN_MASK) >> ENA_FMT1_GEN_SHFT; break; case FM_ENA_FMT2: gen = (ena & ENA_FMT2_GEN_MASK) >> ENA_FMT2_GEN_SHFT; break; default: gen = 0; break; } return (gen); } uchar_t fm_ena_format_get(uint64_t ena) { return (ENA_FORMAT(ena)); } uint64_t fm_ena_id_get(uint64_t ena) { uint64_t id; switch (ENA_FORMAT(ena)) { case FM_ENA_FMT1: id = (ena & ENA_FMT1_ID_MASK) >> ENA_FMT1_ID_SHFT; break; case FM_ENA_FMT2: id = (ena & ENA_FMT2_ID_MASK) >> ENA_FMT2_ID_SHFT; break; default: id = 0; } return (id); } uint64_t fm_ena_time_get(uint64_t ena) { uint64_t time; switch (ENA_FORMAT(ena)) { case FM_ENA_FMT1: time = (ena & ENA_FMT1_TIME_MASK) >> ENA_FMT1_TIME_SHFT; break; case FM_ENA_FMT2: time = (ena & ENA_FMT2_TIME_MASK) >> ENA_FMT2_TIME_SHFT; break; default: time = 0; } return (time); } #ifdef _KERNEL /* * Helper function to increment ereport dropped count. Used by the event * rate limiting code to give feedback to the user about how many events were * rate limited by including them in the 'dropped' count. */ void fm_erpt_dropped_increment(void) { atomic_inc_64(&ratelimit_dropped); } void fm_init(void) { zevent_len_cur = 0; zevent_flags = 0; /* Initialize zevent allocation and generation kstats */ fm_ksp = kstat_create("zfs", 0, "fm", "misc", KSTAT_TYPE_NAMED, sizeof (struct erpt_kstat) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); if (fm_ksp != NULL) { fm_ksp->ks_data = &erpt_kstat_data; kstat_install(fm_ksp); } else { cmn_err(CE_NOTE, "failed to create fm/misc kstat\n"); } mutex_init(&zevent_lock, NULL, MUTEX_DEFAULT, NULL); list_create(&zevent_list, sizeof (zevent_t), offsetof(zevent_t, ev_node)); cv_init(&zevent_cv, NULL, CV_DEFAULT, NULL); zfs_ereport_init(); } void fm_fini(void) { int count; zfs_ereport_fini(); zfs_zevent_drain_all(&count); mutex_enter(&zevent_lock); cv_broadcast(&zevent_cv); zevent_flags |= ZEVENT_SHUTDOWN; while (zevent_waiters > 0) { mutex_exit(&zevent_lock); - schedule(); + kpreempt(KPREEMPT_SYNC); mutex_enter(&zevent_lock); } mutex_exit(&zevent_lock); cv_destroy(&zevent_cv); list_destroy(&zevent_list); mutex_destroy(&zevent_lock); if (fm_ksp != NULL) { kstat_delete(fm_ksp); fm_ksp = NULL; } } #endif /* _KERNEL */ ZFS_MODULE_PARAM(zfs_zevent, zfs_zevent_, len_max, INT, ZMOD_RW, "Max event queue length"); diff --git a/module/zfs/spa_log_spacemap.c b/module/zfs/spa_log_spacemap.c index 19e334916bd0..4ecce8214f6a 100644 --- a/module/zfs/spa_log_spacemap.c +++ b/module/zfs/spa_log_spacemap.c @@ -1,1399 +1,1399 @@ /* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or https://opensource.org/licenses/CDDL-1.0. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright (c) 2018, 2019 by Delphix. All rights reserved. */ #include #include #include #include #include #include #include #include /* * Log Space Maps * * Log space maps are an optimization in ZFS metadata allocations for pools * whose workloads are primarily random-writes. Random-write workloads are also * typically random-free, meaning that they are freeing from locations scattered * throughout the pool. This means that each TXG we will have to append some * FREE records to almost every metaslab. With log space maps, we hold their * changes in memory and log them altogether in one pool-wide space map on-disk * for persistence. As more blocks are accumulated in the log space maps and * more unflushed changes are accounted in memory, we flush a selected group * of metaslabs every TXG to relieve memory pressure and potential overheads * when loading the pool. Flushing a metaslab to disk relieves memory as we * flush any unflushed changes from memory to disk (i.e. the metaslab's space * map) and saves import time by making old log space maps obsolete and * eventually destroying them. [A log space map is said to be obsolete when all * its entries have made it to their corresponding metaslab space maps]. * * == On disk data structures used == * * - The pool has a new feature flag and a new entry in the MOS. The feature * is activated when we create the first log space map and remains active * for the lifetime of the pool. The new entry in the MOS Directory [refer * to DMU_POOL_LOG_SPACEMAP_ZAP] is populated with a ZAP whose key-value * pairs are of the form . * This entry is our on-disk reference of the log space maps that exist in * the pool for each TXG and it is used during import to load all the * metaslab unflushed changes in memory. To see how this structure is first * created and later populated refer to spa_generate_syncing_log_sm(). To see * how it is used during import time refer to spa_ld_log_sm_metadata(). * * - Each vdev has a new entry in its vdev_top_zap (see field * VDEV_TOP_ZAP_MS_UNFLUSHED_PHYS_TXGS) which holds the msp_unflushed_txg of * each metaslab in this vdev. This field is the on-disk counterpart of the * in-memory field ms_unflushed_txg which tells us from which TXG and onwards * the metaslab haven't had its changes flushed. During import, we use this * to ignore any entries in the space map log that are for this metaslab but * from a TXG before msp_unflushed_txg. At that point, we also populate its * in-memory counterpart and from there both fields are updated every time * we flush that metaslab. * * - A space map is created every TXG and, during that TXG, it is used to log * all incoming changes (the log space map). When created, the log space map * is referenced in memory by spa_syncing_log_sm and its object ID is inserted * to the space map ZAP mentioned above. The log space map is closed at the * end of the TXG and will be destroyed when it becomes fully obsolete. We * know when a log space map has become obsolete by looking at the oldest * (and smallest) ms_unflushed_txg in the pool. If the value of that is bigger * than the log space map's TXG, then it means that there is no metaslab who * doesn't have the changes from that log and we can therefore destroy it. * [see spa_cleanup_old_sm_logs()]. * * == Important in-memory structures == * * - The per-spa field spa_metaslabs_by_flushed sorts all the metaslabs in * the pool by their ms_unflushed_txg field. It is primarily used for three * reasons. First of all, it is used during flushing where we try to flush * metaslabs in-order from the oldest-flushed to the most recently flushed * every TXG. Secondly, it helps us to lookup the ms_unflushed_txg of the * oldest flushed metaslab to distinguish which log space maps have become * obsolete and which ones are still relevant. Finally it tells us which * metaslabs have unflushed changes in a pool where this feature was just * enabled, as we don't immediately add all of the pool's metaslabs but we * add them over time as they go through metaslab_sync(). The reason that * we do that is to ease these pools into the behavior of the flushing * algorithm (described later on). * * - The per-spa field spa_sm_logs_by_txg can be thought as the in-memory * counterpart of the space map ZAP mentioned above. It's an AVL tree whose * nodes represent the log space maps in the pool. This in-memory * representation of log space maps in the pool sorts the log space maps by * the TXG that they were created (which is also the TXG of their unflushed * changes). It also contains the following extra information for each * space map: * [1] The number of metaslabs that were last flushed on that TXG. This is * important because if that counter is zero and this is the oldest * log then it means that it is also obsolete. * [2] The number of blocks of that space map. This field is used by the * block heuristic of our flushing algorithm (described later on). * It represents how many blocks of metadata changes ZFS had to write * to disk for that TXG. * * - The per-spa field spa_log_summary is a list of entries that summarizes * the metaslab and block counts of all the nodes of the spa_sm_logs_by_txg * AVL tree mentioned above. The reason this exists is that our flushing * algorithm (described later) tries to estimate how many metaslabs to flush * in each TXG by iterating over all the log space maps and looking at their * block counts. Summarizing that information means that don't have to * iterate through each space map, minimizing the runtime overhead of the * flushing algorithm which would be induced in syncing context. In terms of * implementation the log summary is used as a queue: * * we modify or pop entries from its head when we flush metaslabs * * we modify or append entries to its tail when we sync changes. * * - Each metaslab has two new range trees that hold its unflushed changes, * ms_unflushed_allocs and ms_unflushed_frees. These are always disjoint. * * == Flushing algorithm == * * The decision of how many metaslabs to flush on a give TXG is guided by * two heuristics: * * [1] The memory heuristic - * We keep track of the memory used by the unflushed trees from all the * metaslabs [see sus_memused of spa_unflushed_stats] and we ensure that it * stays below a certain threshold which is determined by an arbitrary hard * limit and an arbitrary percentage of the system's memory [see * spa_log_exceeds_memlimit()]. When we see that the memory usage of the * unflushed changes are passing that threshold, we flush metaslabs, which * empties their unflushed range trees, reducing the memory used. * * [2] The block heuristic - * We try to keep the total number of blocks in the log space maps in check * so the log doesn't grow indefinitely and we don't induce a lot of overhead * when loading the pool. At the same time we don't want to flush a lot of * metaslabs too often as this would defeat the purpose of the log space map. * As a result we set a limit in the amount of blocks that we think it's * acceptable for the log space maps to have and try not to cross it. * [see sus_blocklimit from spa_unflushed_stats]. * * In order to stay below the block limit every TXG we have to estimate how * many metaslabs we need to flush based on the current rate of incoming blocks * and our history of log space map blocks. The main idea here is to answer * the question of how many metaslabs do we need to flush in order to get rid * at least an X amount of log space map blocks. We can answer this question * by iterating backwards from the oldest log space map to the newest one * and looking at their metaslab and block counts. At this point the log summary * mentioned above comes handy as it reduces the amount of things that we have * to iterate (even though it may reduce the preciseness of our estimates due * to its aggregation of data). So with that in mind, we project the incoming * rate of the current TXG into the future and attempt to approximate how many * metaslabs would we need to flush from now in order to avoid exceeding our * block limit in different points in the future (granted that we would keep * flushing the same number of metaslabs for every TXG). Then we take the * maximum number from all these estimates to be on the safe side. For the * exact implementation details of algorithm refer to * spa_estimate_metaslabs_to_flush. */ /* * This is used as the block size for the space maps used for the * log space map feature. These space maps benefit from a bigger * block size as we expect to be writing a lot of data to them at * once. */ static const unsigned long zfs_log_sm_blksz = 1ULL << 17; /* * Percentage of the overall system's memory that ZFS allows to be * used for unflushed changes (e.g. the sum of size of all the nodes * in the unflushed trees). * * Note that this value is calculated over 1000000 for finer granularity * (thus the _ppm suffix; reads as "parts per million"). As an example, * the default of 1000 allows 0.1% of memory to be used. */ static unsigned long zfs_unflushed_max_mem_ppm = 1000; /* * Specific hard-limit in memory that ZFS allows to be used for * unflushed changes. */ static unsigned long zfs_unflushed_max_mem_amt = 1ULL << 30; /* * The following tunable determines the number of blocks that can be used for * the log space maps. It is expressed as a percentage of the total number of * metaslabs in the pool (i.e. the default of 400 means that the number of log * blocks is capped at 4 times the number of metaslabs). * * This value exists to tune our flushing algorithm, with higher values * flushing metaslabs less often (doing less I/Os) per TXG versus lower values * flushing metaslabs more aggressively with the upside of saving overheads * when loading the pool. Another factor in this tradeoff is that flushing * less often can potentially lead to better utilization of the metaslab space * map's block size as we accumulate more changes per flush. * * Given that this tunable indirectly controls the flush rate (metaslabs * flushed per txg) and that's why making it a percentage in terms of the * number of metaslabs in the pool makes sense here. * * As a rule of thumb we default this tunable to 400% based on the following: * * 1] Assuming a constant flush rate and a constant incoming rate of log blocks * it is reasonable to expect that the amount of obsolete entries changes * linearly from txg to txg (e.g. the oldest log should have the most * obsolete entries, and the most recent one the least). With this we could * say that, at any given time, about half of the entries in the whole space * map log are obsolete. Thus for every two entries for a metaslab in the * log space map, only one of them is valid and actually makes it to the * metaslab's space map. * [factor of 2] * 2] Each entry in the log space map is guaranteed to be two words while * entries in metaslab space maps are generally single-word. * [an extra factor of 2 - 400% overall] * 3] Even if [1] and [2] are slightly less than 2 each, we haven't taken into * account any consolidation of segments from the log space map to the * unflushed range trees nor their history (e.g. a segment being allocated, * then freed, then allocated again means 3 log space map entries but 0 * metaslab space map entries). Depending on the workload, we've seen ~1.8 * non-obsolete log space map entries per metaslab entry, for a total of * ~600%. Since most of these estimates though are workload dependent, we * default on 400% to be conservative. * * Thus we could say that even in the worst * case of [1] and [2], the factor should end up being 4. * * That said, regardless of the number of metaslabs in the pool we need to * provide upper and lower bounds for the log block limit. * [see zfs_unflushed_log_block_{min,max}] */ static unsigned long zfs_unflushed_log_block_pct = 400; /* * If the number of metaslabs is small and our incoming rate is high, we could * get into a situation that we are flushing all our metaslabs every TXG. Thus * we always allow at least this many log blocks. */ static unsigned long zfs_unflushed_log_block_min = 1000; /* * If the log becomes too big, the import time of the pool can take a hit in * terms of performance. Thus we have a hard limit in the size of the log in * terms of blocks. */ static unsigned long zfs_unflushed_log_block_max = (1ULL << 17); /* * Also we have a hard limit in the size of the log in terms of dirty TXGs. */ static unsigned long zfs_unflushed_log_txg_max = 1000; /* * Max # of rows allowed for the log_summary. The tradeoff here is accuracy and * stability of the flushing algorithm (longer summary) vs its runtime overhead * (smaller summary is faster to traverse). */ static unsigned long zfs_max_logsm_summary_length = 10; /* * Tunable that sets the lower bound on the metaslabs to flush every TXG. * * Setting this to 0 has no effect since if the pool is idle we won't even be * creating log space maps and therefore we won't be flushing. On the other * hand if the pool has any incoming workload our block heuristic will start * flushing metaslabs anyway. * * The point of this tunable is to be used in extreme cases where we really * want to flush more metaslabs than our adaptable heuristic plans to flush. */ static unsigned long zfs_min_metaslabs_to_flush = 1; /* * Tunable that specifies how far in the past do we want to look when trying to * estimate the incoming log blocks for the current TXG. * * Setting this too high may not only increase runtime but also minimize the * effect of the incoming rates from the most recent TXGs as we take the * average over all the blocks that we walk * [see spa_estimate_incoming_log_blocks]. */ static unsigned long zfs_max_log_walking = 5; /* * This tunable exists solely for testing purposes. It ensures that the log * spacemaps are not flushed and destroyed during export in order for the * relevant log spacemap import code paths to be tested (effectively simulating * a crash). */ int zfs_keep_log_spacemaps_at_export = 0; static uint64_t spa_estimate_incoming_log_blocks(spa_t *spa) { ASSERT3U(spa_sync_pass(spa), ==, 1); uint64_t steps = 0, sum = 0; for (spa_log_sm_t *sls = avl_last(&spa->spa_sm_logs_by_txg); sls != NULL && steps < zfs_max_log_walking; sls = AVL_PREV(&spa->spa_sm_logs_by_txg, sls)) { if (sls->sls_txg == spa_syncing_txg(spa)) { /* * skip the log created in this TXG as this would * make our estimations inaccurate. */ continue; } sum += sls->sls_nblocks; steps++; } return ((steps > 0) ? DIV_ROUND_UP(sum, steps) : 0); } uint64_t spa_log_sm_blocklimit(spa_t *spa) { return (spa->spa_unflushed_stats.sus_blocklimit); } void spa_log_sm_set_blocklimit(spa_t *spa) { if (!spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP)) { ASSERT0(spa_log_sm_blocklimit(spa)); return; } uint64_t msdcount = 0; for (log_summary_entry_t *e = list_head(&spa->spa_log_summary); e; e = list_next(&spa->spa_log_summary, e)) msdcount += e->lse_msdcount; uint64_t limit = msdcount * zfs_unflushed_log_block_pct / 100; spa->spa_unflushed_stats.sus_blocklimit = MIN(MAX(limit, zfs_unflushed_log_block_min), zfs_unflushed_log_block_max); } uint64_t spa_log_sm_nblocks(spa_t *spa) { return (spa->spa_unflushed_stats.sus_nblocks); } /* * Ensure that the in-memory log space map structures and the summary * have the same block and metaslab counts. */ static void spa_log_summary_verify_counts(spa_t *spa) { ASSERT(spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP)); if ((zfs_flags & ZFS_DEBUG_LOG_SPACEMAP) == 0) return; uint64_t ms_in_avl = avl_numnodes(&spa->spa_metaslabs_by_flushed); uint64_t ms_in_summary = 0, blk_in_summary = 0; for (log_summary_entry_t *e = list_head(&spa->spa_log_summary); e; e = list_next(&spa->spa_log_summary, e)) { ms_in_summary += e->lse_mscount; blk_in_summary += e->lse_blkcount; } uint64_t ms_in_logs = 0, blk_in_logs = 0; for (spa_log_sm_t *sls = avl_first(&spa->spa_sm_logs_by_txg); sls; sls = AVL_NEXT(&spa->spa_sm_logs_by_txg, sls)) { ms_in_logs += sls->sls_mscount; blk_in_logs += sls->sls_nblocks; } VERIFY3U(ms_in_logs, ==, ms_in_summary); VERIFY3U(ms_in_logs, ==, ms_in_avl); VERIFY3U(blk_in_logs, ==, blk_in_summary); VERIFY3U(blk_in_logs, ==, spa_log_sm_nblocks(spa)); } static boolean_t summary_entry_is_full(spa_t *spa, log_summary_entry_t *e, uint64_t txg) { if (e->lse_end == txg) return (0); if (e->lse_txgcount >= DIV_ROUND_UP(zfs_unflushed_log_txg_max, zfs_max_logsm_summary_length)) return (1); uint64_t blocks_per_row = MAX(1, DIV_ROUND_UP(spa_log_sm_blocklimit(spa), zfs_max_logsm_summary_length)); return (blocks_per_row <= e->lse_blkcount); } /* * Update the log summary information to reflect the fact that a metaslab * was flushed or destroyed (e.g due to device removal or pool export/destroy). * * We typically flush the oldest flushed metaslab so the first (and oldest) * entry of the summary is updated. However if that metaslab is getting loaded * we may flush the second oldest one which may be part of an entry later in * the summary. Moreover, if we call into this function from metaslab_fini() * the metaslabs probably won't be ordered by ms_unflushed_txg. Thus we ask * for a txg as an argument so we can locate the appropriate summary entry for * the metaslab. */ void spa_log_summary_decrement_mscount(spa_t *spa, uint64_t txg, boolean_t dirty) { /* * We don't track summary data for read-only pools and this function * can be called from metaslab_fini(). In that case return immediately. */ if (!spa_writeable(spa)) return; log_summary_entry_t *target = NULL; for (log_summary_entry_t *e = list_head(&spa->spa_log_summary); e != NULL; e = list_next(&spa->spa_log_summary, e)) { if (e->lse_start > txg) break; target = e; } if (target == NULL || target->lse_mscount == 0) { /* * We didn't find a summary entry for this metaslab. We must be * at the teardown of a spa_load() attempt that got an error * while reading the log space maps. */ VERIFY3S(spa_load_state(spa), ==, SPA_LOAD_ERROR); return; } target->lse_mscount--; if (dirty) target->lse_msdcount--; } /* * Update the log summary information to reflect the fact that we destroyed * old log space maps. Since we can only destroy the oldest log space maps, * we decrement the block count of the oldest summary entry and potentially * destroy it when that count hits 0. * * This function is called after a metaslab is flushed and typically that * metaslab is the oldest flushed, which means that this function will * typically decrement the block count of the first entry of the summary and * potentially free it if the block count gets to zero (its metaslab count * should be zero too at that point). * * There are certain scenarios though that don't work exactly like that so we * need to account for them: * * Scenario [1]: It is possible that after we flushed the oldest flushed * metaslab and we destroyed the oldest log space map, more recent logs had 0 * metaslabs pointing to them so we got rid of them too. This can happen due * to metaslabs being destroyed through device removal, or because the oldest * flushed metaslab was loading but we kept flushing more recently flushed * metaslabs due to the memory pressure of unflushed changes. Because of that, * we always iterate from the beginning of the summary and if blocks_gone is * bigger than the block_count of the current entry we free that entry (we * expect its metaslab count to be zero), we decrement blocks_gone and on to * the next entry repeating this procedure until blocks_gone gets decremented * to 0. Doing this also works for the typical case mentioned above. * * Scenario [2]: The oldest flushed metaslab isn't necessarily accounted by * the first (and oldest) entry in the summary. If the first few entries of * the summary were only accounting metaslabs from a device that was just * removed, then the current oldest flushed metaslab could be accounted by an * entry somewhere in the middle of the summary. Moreover flushing that * metaslab will destroy all the log space maps older than its ms_unflushed_txg * because they became obsolete after the removal. Thus, iterating as we did * for scenario [1] works out for this case too. * * Scenario [3]: At times we decide to flush all the metaslabs in the pool * in one TXG (either because we are exporting the pool or because our flushing * heuristics decided to do so). When that happens all the log space maps get * destroyed except the one created for the current TXG which doesn't have * any log blocks yet. As log space maps get destroyed with every metaslab that * we flush, entries in the summary are also destroyed. This brings a weird * corner-case when we flush the last metaslab and the log space map of the * current TXG is in the same summary entry with other log space maps that * are older. When that happens we are eventually left with this one last * summary entry whose blocks are gone (blocks_gone equals the entry's block * count) but its metaslab count is non-zero (because it accounts all the * metaslabs in the pool as they all got flushed). Under this scenario we can't * free this last summary entry as it's referencing all the metaslabs in the * pool and its block count will get incremented at the end of this sync (when * we close the syncing log space map). Thus we just decrement its current * block count and leave it alone. In the case that the pool gets exported, * its metaslab count will be decremented over time as we call metaslab_fini() * for all the metaslabs in the pool and the entry will be freed at * spa_unload_log_sm_metadata(). */ void spa_log_summary_decrement_blkcount(spa_t *spa, uint64_t blocks_gone) { log_summary_entry_t *e = list_head(&spa->spa_log_summary); if (e->lse_txgcount > 0) e->lse_txgcount--; for (; e != NULL; e = list_head(&spa->spa_log_summary)) { if (e->lse_blkcount > blocks_gone) { e->lse_blkcount -= blocks_gone; blocks_gone = 0; break; } else if (e->lse_mscount == 0) { /* remove obsolete entry */ blocks_gone -= e->lse_blkcount; list_remove(&spa->spa_log_summary, e); kmem_free(e, sizeof (log_summary_entry_t)); } else { /* Verify that this is scenario [3] mentioned above. */ VERIFY3U(blocks_gone, ==, e->lse_blkcount); /* * Assert that this is scenario [3] further by ensuring * that this is the only entry in the summary. */ VERIFY3P(e, ==, list_tail(&spa->spa_log_summary)); ASSERT3P(e, ==, list_head(&spa->spa_log_summary)); blocks_gone = e->lse_blkcount = 0; break; } } /* * Ensure that there is no way we are trying to remove more blocks * than the # of blocks in the summary. */ ASSERT0(blocks_gone); } void spa_log_sm_decrement_mscount(spa_t *spa, uint64_t txg) { spa_log_sm_t target = { .sls_txg = txg }; spa_log_sm_t *sls = avl_find(&spa->spa_sm_logs_by_txg, &target, NULL); if (sls == NULL) { /* * We must be at the teardown of a spa_load() attempt that * got an error while reading the log space maps. */ VERIFY3S(spa_load_state(spa), ==, SPA_LOAD_ERROR); return; } ASSERT(sls->sls_mscount > 0); sls->sls_mscount--; } void spa_log_sm_increment_current_mscount(spa_t *spa) { spa_log_sm_t *last_sls = avl_last(&spa->spa_sm_logs_by_txg); ASSERT3U(last_sls->sls_txg, ==, spa_syncing_txg(spa)); last_sls->sls_mscount++; } static void summary_add_data(spa_t *spa, uint64_t txg, uint64_t metaslabs_flushed, uint64_t metaslabs_dirty, uint64_t nblocks) { log_summary_entry_t *e = list_tail(&spa->spa_log_summary); if (e == NULL || summary_entry_is_full(spa, e, txg)) { e = kmem_zalloc(sizeof (log_summary_entry_t), KM_SLEEP); e->lse_start = e->lse_end = txg; e->lse_txgcount = 1; list_insert_tail(&spa->spa_log_summary, e); } ASSERT3U(e->lse_start, <=, txg); if (e->lse_end < txg) { e->lse_end = txg; e->lse_txgcount++; } e->lse_mscount += metaslabs_flushed; e->lse_msdcount += metaslabs_dirty; e->lse_blkcount += nblocks; } static void spa_log_summary_add_incoming_blocks(spa_t *spa, uint64_t nblocks) { summary_add_data(spa, spa_syncing_txg(spa), 0, 0, nblocks); } void spa_log_summary_add_flushed_metaslab(spa_t *spa, boolean_t dirty) { summary_add_data(spa, spa_syncing_txg(spa), 1, dirty ? 1 : 0, 0); } void spa_log_summary_dirty_flushed_metaslab(spa_t *spa, uint64_t txg) { log_summary_entry_t *target = NULL; for (log_summary_entry_t *e = list_head(&spa->spa_log_summary); e != NULL; e = list_next(&spa->spa_log_summary, e)) { if (e->lse_start > txg) break; target = e; } ASSERT3P(target, !=, NULL); ASSERT3U(target->lse_mscount, !=, 0); target->lse_msdcount++; } /* * This function attempts to estimate how many metaslabs should * we flush to satisfy our block heuristic for the log spacemap * for the upcoming TXGs. * * Specifically, it first tries to estimate the number of incoming * blocks in this TXG. Then by projecting that incoming rate to * future TXGs and using the log summary, it figures out how many * flushes we would need to do for future TXGs individually to * stay below our block limit and returns the maximum number of * flushes from those estimates. */ static uint64_t spa_estimate_metaslabs_to_flush(spa_t *spa) { ASSERT(spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP)); ASSERT3U(spa_sync_pass(spa), ==, 1); ASSERT(spa_log_sm_blocklimit(spa) != 0); /* * This variable contains the incoming rate that will be projected * and used for our flushing estimates in the future. */ uint64_t incoming = spa_estimate_incoming_log_blocks(spa); /* * At any point in time this variable tells us how many * TXGs in the future we are so we can make our estimations. */ uint64_t txgs_in_future = 1; /* * This variable tells us how much room do we have until we hit * our limit. When it goes negative, it means that we've exceeded * our limit and we need to flush. * * Note that since we start at the first TXG in the future (i.e. * txgs_in_future starts from 1) we already decrement this * variable by the incoming rate. */ int64_t available_blocks = spa_log_sm_blocklimit(spa) - spa_log_sm_nblocks(spa) - incoming; int64_t available_txgs = zfs_unflushed_log_txg_max; for (log_summary_entry_t *e = list_head(&spa->spa_log_summary); e; e = list_next(&spa->spa_log_summary, e)) available_txgs -= e->lse_txgcount; /* * This variable tells us the total number of flushes needed to * keep the log size within the limit when we reach txgs_in_future. */ uint64_t total_flushes = 0; /* Holds the current maximum of our estimates so far. */ uint64_t max_flushes_pertxg = zfs_min_metaslabs_to_flush; /* * For our estimations we only look as far in the future * as the summary allows us. */ for (log_summary_entry_t *e = list_head(&spa->spa_log_summary); e; e = list_next(&spa->spa_log_summary, e)) { /* * If there is still room before we exceed our limit * then keep skipping TXGs accumulating more blocks * based on the incoming rate until we exceed it. */ if (available_blocks >= 0 && available_txgs >= 0) { uint64_t skip_txgs = MIN(available_txgs + 1, (available_blocks / incoming) + 1); available_blocks -= (skip_txgs * incoming); available_txgs -= skip_txgs; txgs_in_future += skip_txgs; ASSERT3S(available_blocks, >=, -incoming); ASSERT3S(available_txgs, >=, -1); } /* * At this point we're far enough into the future where * the limit was just exceeded and we flush metaslabs * based on the current entry in the summary, updating * our available_blocks. */ ASSERT(available_blocks < 0 || available_txgs < 0); available_blocks += e->lse_blkcount; available_txgs += e->lse_txgcount; total_flushes += e->lse_msdcount; /* * Keep the running maximum of the total_flushes that * we've done so far over the number of TXGs in the * future that we are. The idea here is to estimate * the average number of flushes that we should do * every TXG so that when we are that many TXGs in the * future we stay under the limit. */ max_flushes_pertxg = MAX(max_flushes_pertxg, DIV_ROUND_UP(total_flushes, txgs_in_future)); } return (max_flushes_pertxg); } uint64_t spa_log_sm_memused(spa_t *spa) { return (spa->spa_unflushed_stats.sus_memused); } static boolean_t spa_log_exceeds_memlimit(spa_t *spa) { if (spa_log_sm_memused(spa) > zfs_unflushed_max_mem_amt) return (B_TRUE); uint64_t system_mem_allowed = ((physmem * PAGESIZE) * zfs_unflushed_max_mem_ppm) / 1000000; if (spa_log_sm_memused(spa) > system_mem_allowed) return (B_TRUE); return (B_FALSE); } boolean_t spa_flush_all_logs_requested(spa_t *spa) { return (spa->spa_log_flushall_txg != 0); } void spa_flush_metaslabs(spa_t *spa, dmu_tx_t *tx) { uint64_t txg = dmu_tx_get_txg(tx); if (spa_sync_pass(spa) != 1) return; if (!spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP)) return; /* * If we don't have any metaslabs with unflushed changes * return immediately. */ if (avl_numnodes(&spa->spa_metaslabs_by_flushed) == 0) return; /* * During SPA export we leave a few empty TXGs to go by [see * spa_final_dirty_txg() to understand why]. For this specific * case, it is important to not flush any metaslabs as that * would dirty this TXG. * * That said, during one of these dirty TXGs that is less or * equal to spa_final_dirty(), spa_unload() will request that * we try to flush all the metaslabs for that TXG before * exporting the pool, thus we ensure that we didn't get a * request of flushing everything before we attempt to return * immediately. */ if (spa->spa_uberblock.ub_rootbp.blk_birth < txg && !dmu_objset_is_dirty(spa_meta_objset(spa), txg) && !spa_flush_all_logs_requested(spa)) return; /* * We need to generate a log space map before flushing because this * will set up the in-memory data (i.e. node in spa_sm_logs_by_txg) * for this TXG's flushed metaslab count (aka sls_mscount which is * manipulated in many ways down the metaslab_flush() codepath). * * That is not to say that we may generate a log space map when we * don't need it. If we are flushing metaslabs, that means that we * were going to write changes to disk anyway, so even if we were * not flushing, a log space map would have been created anyway in * metaslab_sync(). */ spa_generate_syncing_log_sm(spa, tx); /* * This variable tells us how many metaslabs we want to flush based * on the block-heuristic of our flushing algorithm (see block comment * of log space map feature). We also decrement this as we flush * metaslabs and attempt to destroy old log space maps. */ uint64_t want_to_flush; if (spa_flush_all_logs_requested(spa)) { ASSERT3S(spa_state(spa), ==, POOL_STATE_EXPORTED); want_to_flush = UINT64_MAX; } else { want_to_flush = spa_estimate_metaslabs_to_flush(spa); } /* Used purely for verification purposes */ uint64_t visited = 0; /* * Ideally we would only iterate through spa_metaslabs_by_flushed * using only one variable (curr). We can't do that because * metaslab_flush() mutates position of curr in the AVL when * it flushes that metaslab by moving it to the end of the tree. * Thus we always keep track of the original next node of the * current node (curr) in another variable (next). */ metaslab_t *next = NULL; for (metaslab_t *curr = avl_first(&spa->spa_metaslabs_by_flushed); curr != NULL; curr = next) { next = AVL_NEXT(&spa->spa_metaslabs_by_flushed, curr); /* * If this metaslab has been flushed this txg then we've done * a full circle over the metaslabs. */ if (metaslab_unflushed_txg(curr) == txg) break; /* * If we are done flushing for the block heuristic and the * unflushed changes don't exceed the memory limit just stop. */ if (want_to_flush == 0 && !spa_log_exceeds_memlimit(spa)) break; if (metaslab_unflushed_dirty(curr)) { mutex_enter(&curr->ms_sync_lock); mutex_enter(&curr->ms_lock); metaslab_flush(curr, tx); mutex_exit(&curr->ms_lock); mutex_exit(&curr->ms_sync_lock); if (want_to_flush > 0) want_to_flush--; } else metaslab_unflushed_bump(curr, tx, B_FALSE); visited++; } ASSERT3U(avl_numnodes(&spa->spa_metaslabs_by_flushed), >=, visited); spa_log_sm_set_blocklimit(spa); } /* * Close the log space map for this TXG and update the block counts * for the log's in-memory structure and the summary. */ void spa_sync_close_syncing_log_sm(spa_t *spa) { if (spa_syncing_log_sm(spa) == NULL) return; ASSERT(spa_feature_is_active(spa, SPA_FEATURE_LOG_SPACEMAP)); spa_log_sm_t *sls = avl_last(&spa->spa_sm_logs_by_txg); ASSERT3U(sls->sls_txg, ==, spa_syncing_txg(spa)); sls->sls_nblocks = space_map_nblocks(spa_syncing_log_sm(spa)); spa->spa_unflushed_stats.sus_nblocks += sls->sls_nblocks; /* * Note that we can't assert that sls_mscount is not 0, * because there is the case where the first metaslab * in spa_metaslabs_by_flushed is loading and we were * not able to flush any metaslabs the current TXG. */ ASSERT(sls->sls_nblocks != 0); spa_log_summary_add_incoming_blocks(spa, sls->sls_nblocks); spa_log_summary_verify_counts(spa); space_map_close(spa->spa_syncing_log_sm); spa->spa_syncing_log_sm = NULL; /* * At this point we tried to flush as many metaslabs as we * can as the pool is getting exported. Reset the "flush all" * so the last few TXGs before closing the pool can be empty * (e.g. not dirty). */ if (spa_flush_all_logs_requested(spa)) { ASSERT3S(spa_state(spa), ==, POOL_STATE_EXPORTED); spa->spa_log_flushall_txg = 0; } } void spa_cleanup_old_sm_logs(spa_t *spa, dmu_tx_t *tx) { objset_t *mos = spa_meta_objset(spa); uint64_t spacemap_zap; int error = zap_lookup(mos, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_LOG_SPACEMAP_ZAP, sizeof (spacemap_zap), 1, &spacemap_zap); if (error == ENOENT) { ASSERT(avl_is_empty(&spa->spa_sm_logs_by_txg)); return; } VERIFY0(error); metaslab_t *oldest = avl_first(&spa->spa_metaslabs_by_flushed); uint64_t oldest_flushed_txg = metaslab_unflushed_txg(oldest); /* Free all log space maps older than the oldest_flushed_txg. */ for (spa_log_sm_t *sls = avl_first(&spa->spa_sm_logs_by_txg); sls && sls->sls_txg < oldest_flushed_txg; sls = avl_first(&spa->spa_sm_logs_by_txg)) { ASSERT0(sls->sls_mscount); avl_remove(&spa->spa_sm_logs_by_txg, sls); space_map_free_obj(mos, sls->sls_sm_obj, tx); VERIFY0(zap_remove_int(mos, spacemap_zap, sls->sls_txg, tx)); spa_log_summary_decrement_blkcount(spa, sls->sls_nblocks); spa->spa_unflushed_stats.sus_nblocks -= sls->sls_nblocks; kmem_free(sls, sizeof (spa_log_sm_t)); } } static spa_log_sm_t * spa_log_sm_alloc(uint64_t sm_obj, uint64_t txg) { spa_log_sm_t *sls = kmem_zalloc(sizeof (*sls), KM_SLEEP); sls->sls_sm_obj = sm_obj; sls->sls_txg = txg; return (sls); } void spa_generate_syncing_log_sm(spa_t *spa, dmu_tx_t *tx) { uint64_t txg = dmu_tx_get_txg(tx); objset_t *mos = spa_meta_objset(spa); if (spa_syncing_log_sm(spa) != NULL) return; if (!spa_feature_is_enabled(spa, SPA_FEATURE_LOG_SPACEMAP)) return; uint64_t spacemap_zap; int error = zap_lookup(mos, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_LOG_SPACEMAP_ZAP, sizeof (spacemap_zap), 1, &spacemap_zap); if (error == ENOENT) { ASSERT(avl_is_empty(&spa->spa_sm_logs_by_txg)); error = 0; spacemap_zap = zap_create(mos, DMU_OTN_ZAP_METADATA, DMU_OT_NONE, 0, tx); VERIFY0(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_LOG_SPACEMAP_ZAP, sizeof (spacemap_zap), 1, &spacemap_zap, tx)); spa_feature_incr(spa, SPA_FEATURE_LOG_SPACEMAP, tx); } VERIFY0(error); uint64_t sm_obj; ASSERT3U(zap_lookup_int_key(mos, spacemap_zap, txg, &sm_obj), ==, ENOENT); sm_obj = space_map_alloc(mos, zfs_log_sm_blksz, tx); VERIFY0(zap_add_int_key(mos, spacemap_zap, txg, sm_obj, tx)); avl_add(&spa->spa_sm_logs_by_txg, spa_log_sm_alloc(sm_obj, txg)); /* * We pass UINT64_MAX as the space map's representation size * and SPA_MINBLOCKSHIFT as the shift, to make the space map * accept any sorts of segments since there's no real advantage * to being more restrictive (given that we're already going * to be using 2-word entries). */ VERIFY0(space_map_open(&spa->spa_syncing_log_sm, mos, sm_obj, 0, UINT64_MAX, SPA_MINBLOCKSHIFT)); spa_log_sm_set_blocklimit(spa); } /* * Find all the log space maps stored in the space map ZAP and sort * them by their TXG in spa_sm_logs_by_txg. */ static int spa_ld_log_sm_metadata(spa_t *spa) { int error; uint64_t spacemap_zap; ASSERT(avl_is_empty(&spa->spa_sm_logs_by_txg)); error = zap_lookup(spa_meta_objset(spa), DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_LOG_SPACEMAP_ZAP, sizeof (spacemap_zap), 1, &spacemap_zap); if (error == ENOENT) { /* the space map ZAP doesn't exist yet */ return (0); } else if (error != 0) { spa_load_failed(spa, "spa_ld_log_sm_metadata(): failed at " "zap_lookup(DMU_POOL_DIRECTORY_OBJECT) [error %d]", error); return (error); } zap_cursor_t zc; zap_attribute_t za; for (zap_cursor_init(&zc, spa_meta_objset(spa), spacemap_zap); (error = zap_cursor_retrieve(&zc, &za)) == 0; zap_cursor_advance(&zc)) { uint64_t log_txg = zfs_strtonum(za.za_name, NULL); spa_log_sm_t *sls = spa_log_sm_alloc(za.za_first_integer, log_txg); avl_add(&spa->spa_sm_logs_by_txg, sls); } zap_cursor_fini(&zc); if (error != ENOENT) { spa_load_failed(spa, "spa_ld_log_sm_metadata(): failed at " "zap_cursor_retrieve(spacemap_zap) [error %d]", error); return (error); } for (metaslab_t *m = avl_first(&spa->spa_metaslabs_by_flushed); m; m = AVL_NEXT(&spa->spa_metaslabs_by_flushed, m)) { spa_log_sm_t target = { .sls_txg = metaslab_unflushed_txg(m) }; spa_log_sm_t *sls = avl_find(&spa->spa_sm_logs_by_txg, &target, NULL); /* * At this point if sls is zero it means that a bug occurred * in ZFS the last time the pool was open or earlier in the * import code path. In general, we would have placed a * VERIFY() here or in this case just let the kernel panic * with NULL pointer dereference when incrementing sls_mscount, * but since this is the import code path we can be a bit more * lenient. Thus, for DEBUG bits we always cause a panic, while * in production we log the error and just fail the import. */ ASSERT(sls != NULL); if (sls == NULL) { spa_load_failed(spa, "spa_ld_log_sm_metadata(): bug " "encountered: could not find log spacemap for " "TXG %llu [error %d]", (u_longlong_t)metaslab_unflushed_txg(m), ENOENT); return (ENOENT); } sls->sls_mscount++; } return (0); } typedef struct spa_ld_log_sm_arg { spa_t *slls_spa; uint64_t slls_txg; } spa_ld_log_sm_arg_t; static int spa_ld_log_sm_cb(space_map_entry_t *sme, void *arg) { uint64_t offset = sme->sme_offset; uint64_t size = sme->sme_run; uint32_t vdev_id = sme->sme_vdev; spa_ld_log_sm_arg_t *slls = arg; spa_t *spa = slls->slls_spa; vdev_t *vd = vdev_lookup_top(spa, vdev_id); /* * If the vdev has been removed (i.e. it is indirect or a hole) * skip this entry. The contents of this vdev have already moved * elsewhere. */ if (!vdev_is_concrete(vd)) return (0); metaslab_t *ms = vd->vdev_ms[offset >> vd->vdev_ms_shift]; ASSERT(!ms->ms_loaded); /* * If we have already flushed entries for this TXG to this * metaslab's space map, then ignore it. Note that we flush * before processing any allocations/frees for that TXG, so * the metaslab's space map only has entries from *before* * the unflushed TXG. */ if (slls->slls_txg < metaslab_unflushed_txg(ms)) return (0); switch (sme->sme_type) { case SM_ALLOC: range_tree_remove_xor_add_segment(offset, offset + size, ms->ms_unflushed_frees, ms->ms_unflushed_allocs); break; case SM_FREE: range_tree_remove_xor_add_segment(offset, offset + size, ms->ms_unflushed_allocs, ms->ms_unflushed_frees); break; default: panic("invalid maptype_t"); break; } if (!metaslab_unflushed_dirty(ms)) { metaslab_set_unflushed_dirty(ms, B_TRUE); spa_log_summary_dirty_flushed_metaslab(spa, metaslab_unflushed_txg(ms)); } return (0); } static int spa_ld_log_sm_data(spa_t *spa) { spa_log_sm_t *sls, *psls; int error = 0; /* * If we are not going to do any writes there is no need * to read the log space maps. */ if (!spa_writeable(spa)) return (0); ASSERT0(spa->spa_unflushed_stats.sus_nblocks); ASSERT0(spa->spa_unflushed_stats.sus_memused); hrtime_t read_logs_starttime = gethrtime(); /* Prefetch log spacemaps dnodes. */ for (sls = avl_first(&spa->spa_sm_logs_by_txg); sls; sls = AVL_NEXT(&spa->spa_sm_logs_by_txg, sls)) { dmu_prefetch(spa_meta_objset(spa), sls->sls_sm_obj, 0, 0, 0, ZIO_PRIORITY_SYNC_READ); } uint_t pn = 0; uint64_t ps = 0; psls = sls = avl_first(&spa->spa_sm_logs_by_txg); while (sls != NULL) { /* Prefetch log spacemaps up to 16 TXGs or MBs ahead. */ if (psls != NULL && pn < 16 && (pn < 2 || ps < 2 * dmu_prefetch_max)) { error = space_map_open(&psls->sls_sm, spa_meta_objset(spa), psls->sls_sm_obj, 0, UINT64_MAX, SPA_MINBLOCKSHIFT); if (error != 0) { spa_load_failed(spa, "spa_ld_log_sm_data(): " "failed at space_map_open(obj=%llu) " "[error %d]", (u_longlong_t)sls->sls_sm_obj, error); goto out; } dmu_prefetch(spa_meta_objset(spa), psls->sls_sm_obj, 0, 0, space_map_length(psls->sls_sm), ZIO_PRIORITY_ASYNC_READ); pn++; ps += space_map_length(psls->sls_sm); psls = AVL_NEXT(&spa->spa_sm_logs_by_txg, psls); continue; } /* Load TXG log spacemap into ms_unflushed_allocs/frees. */ - cond_resched(); + kpreempt(KPREEMPT_SYNC); ASSERT0(sls->sls_nblocks); sls->sls_nblocks = space_map_nblocks(sls->sls_sm); spa->spa_unflushed_stats.sus_nblocks += sls->sls_nblocks; summary_add_data(spa, sls->sls_txg, sls->sls_mscount, 0, sls->sls_nblocks); struct spa_ld_log_sm_arg vla = { .slls_spa = spa, .slls_txg = sls->sls_txg }; error = space_map_iterate(sls->sls_sm, space_map_length(sls->sls_sm), spa_ld_log_sm_cb, &vla); if (error != 0) { spa_load_failed(spa, "spa_ld_log_sm_data(): failed " "at space_map_iterate(obj=%llu) [error %d]", (u_longlong_t)sls->sls_sm_obj, error); goto out; } pn--; ps -= space_map_length(sls->sls_sm); space_map_close(sls->sls_sm); sls->sls_sm = NULL; sls = AVL_NEXT(&spa->spa_sm_logs_by_txg, sls); /* Update log block limits considering just loaded. */ spa_log_sm_set_blocklimit(spa); } hrtime_t read_logs_endtime = gethrtime(); spa_load_note(spa, "read %llu log space maps (%llu total blocks - blksz = %llu bytes) " "in %lld ms", (u_longlong_t)avl_numnodes(&spa->spa_sm_logs_by_txg), (u_longlong_t)spa_log_sm_nblocks(spa), (u_longlong_t)zfs_log_sm_blksz, (longlong_t)((read_logs_endtime - read_logs_starttime) / 1000000)); out: if (error != 0) { for (spa_log_sm_t *sls = avl_first(&spa->spa_sm_logs_by_txg); sls; sls = AVL_NEXT(&spa->spa_sm_logs_by_txg, sls)) { if (sls->sls_sm) { space_map_close(sls->sls_sm); sls->sls_sm = NULL; } } } else { ASSERT0(pn); ASSERT0(ps); } /* * Now that the metaslabs contain their unflushed changes: * [1] recalculate their actual allocated space * [2] recalculate their weights * [3] sum up the memory usage of their unflushed range trees * [4] optionally load them, if debug_load is set * * Note that even in the case where we get here because of an * error (e.g. error != 0), we still want to update the fields * below in order to have a proper teardown in spa_unload(). */ for (metaslab_t *m = avl_first(&spa->spa_metaslabs_by_flushed); m != NULL; m = AVL_NEXT(&spa->spa_metaslabs_by_flushed, m)) { mutex_enter(&m->ms_lock); m->ms_allocated_space = space_map_allocated(m->ms_sm) + range_tree_space(m->ms_unflushed_allocs) - range_tree_space(m->ms_unflushed_frees); vdev_t *vd = m->ms_group->mg_vd; metaslab_space_update(vd, m->ms_group->mg_class, range_tree_space(m->ms_unflushed_allocs), 0, 0); metaslab_space_update(vd, m->ms_group->mg_class, -range_tree_space(m->ms_unflushed_frees), 0, 0); ASSERT0(m->ms_weight & METASLAB_ACTIVE_MASK); metaslab_recalculate_weight_and_sort(m); spa->spa_unflushed_stats.sus_memused += metaslab_unflushed_changes_memused(m); if (metaslab_debug_load && m->ms_sm != NULL) { VERIFY0(metaslab_load(m)); metaslab_set_selected_txg(m, 0); } mutex_exit(&m->ms_lock); } return (error); } static int spa_ld_unflushed_txgs(vdev_t *vd) { spa_t *spa = vd->vdev_spa; objset_t *mos = spa_meta_objset(spa); if (vd->vdev_top_zap == 0) return (0); uint64_t object = 0; int error = zap_lookup(mos, vd->vdev_top_zap, VDEV_TOP_ZAP_MS_UNFLUSHED_PHYS_TXGS, sizeof (uint64_t), 1, &object); if (error == ENOENT) return (0); else if (error != 0) { spa_load_failed(spa, "spa_ld_unflushed_txgs(): failed at " "zap_lookup(vdev_top_zap=%llu) [error %d]", (u_longlong_t)vd->vdev_top_zap, error); return (error); } for (uint64_t m = 0; m < vd->vdev_ms_count; m++) { metaslab_t *ms = vd->vdev_ms[m]; ASSERT(ms != NULL); metaslab_unflushed_phys_t entry; uint64_t entry_size = sizeof (entry); uint64_t entry_offset = ms->ms_id * entry_size; error = dmu_read(mos, object, entry_offset, entry_size, &entry, 0); if (error != 0) { spa_load_failed(spa, "spa_ld_unflushed_txgs(): " "failed at dmu_read(obj=%llu) [error %d]", (u_longlong_t)object, error); return (error); } ms->ms_unflushed_txg = entry.msp_unflushed_txg; ms->ms_unflushed_dirty = B_FALSE; ASSERT(range_tree_is_empty(ms->ms_unflushed_allocs)); ASSERT(range_tree_is_empty(ms->ms_unflushed_frees)); if (ms->ms_unflushed_txg != 0) { mutex_enter(&spa->spa_flushed_ms_lock); avl_add(&spa->spa_metaslabs_by_flushed, ms); mutex_exit(&spa->spa_flushed_ms_lock); } } return (0); } /* * Read all the log space map entries into their respective * metaslab unflushed trees and keep them sorted by TXG in the * SPA's metadata. In addition, setup all the metadata for the * memory and the block heuristics. */ int spa_ld_log_spacemaps(spa_t *spa) { int error; spa_log_sm_set_blocklimit(spa); for (uint64_t c = 0; c < spa->spa_root_vdev->vdev_children; c++) { vdev_t *vd = spa->spa_root_vdev->vdev_child[c]; error = spa_ld_unflushed_txgs(vd); if (error != 0) return (error); } error = spa_ld_log_sm_metadata(spa); if (error != 0) return (error); /* * Note: we don't actually expect anything to change at this point * but we grab the config lock so we don't fail any assertions * when using vdev_lookup_top(). */ spa_config_enter(spa, SCL_CONFIG, FTAG, RW_READER); error = spa_ld_log_sm_data(spa); spa_config_exit(spa, SCL_CONFIG, FTAG); return (error); } /* BEGIN CSTYLED */ ZFS_MODULE_PARAM(zfs, zfs_, unflushed_max_mem_amt, ULONG, ZMOD_RW, "Specific hard-limit in memory that ZFS allows to be used for " "unflushed changes"); ZFS_MODULE_PARAM(zfs, zfs_, unflushed_max_mem_ppm, ULONG, ZMOD_RW, "Percentage of the overall system memory that ZFS allows to be " "used for unflushed changes (value is calculated over 1000000 for " "finer granularity)"); ZFS_MODULE_PARAM(zfs, zfs_, unflushed_log_block_max, ULONG, ZMOD_RW, "Hard limit (upper-bound) in the size of the space map log " "in terms of blocks."); ZFS_MODULE_PARAM(zfs, zfs_, unflushed_log_block_min, ULONG, ZMOD_RW, "Lower-bound limit for the maximum amount of blocks allowed in " "log spacemap (see zfs_unflushed_log_block_max)"); ZFS_MODULE_PARAM(zfs, zfs_, unflushed_log_txg_max, ULONG, ZMOD_RW, "Hard limit (upper-bound) in the size of the space map log " "in terms of dirty TXGs."); ZFS_MODULE_PARAM(zfs, zfs_, unflushed_log_block_pct, ULONG, ZMOD_RW, "Tunable used to determine the number of blocks that can be used for " "the spacemap log, expressed as a percentage of the total number of " "metaslabs in the pool (e.g. 400 means the number of log blocks is " "capped at 4 times the number of metaslabs)"); ZFS_MODULE_PARAM(zfs, zfs_, max_log_walking, ULONG, ZMOD_RW, "The number of past TXGs that the flushing algorithm of the log " "spacemap feature uses to estimate incoming log blocks"); ZFS_MODULE_PARAM(zfs, zfs_, keep_log_spacemaps_at_export, INT, ZMOD_RW, "Prevent the log spacemaps from being flushed and destroyed " "during pool export/destroy"); /* END CSTYLED */ ZFS_MODULE_PARAM(zfs, zfs_, max_logsm_summary_length, ULONG, ZMOD_RW, "Maximum number of rows allowed in the summary of the spacemap log"); ZFS_MODULE_PARAM(zfs, zfs_, min_metaslabs_to_flush, ULONG, ZMOD_RW, "Minimum number of metaslabs to flush per dirty TXG");