Index: head/sys/fs/nullfs/null.h =================================================================== --- head/sys/fs/nullfs/null.h (revision 357198) +++ head/sys/fs/nullfs/null.h (revision 357199) @@ -1,96 +1,96 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1992, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software donated to Berkeley by * Jan-Simon Pendry. * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)null.h 8.3 (Berkeley) 8/20/94 * * $FreeBSD$ */ #ifndef FS_NULL_H #define FS_NULL_H #define NULLM_CACHE 0x0001 struct null_mount { struct mount *nullm_vfs; - struct vnode *nullm_rootvp; /* Reference to root null_node */ + struct vnode *nullm_lowerrootvp; /* Ref to lower root vnode */ uint64_t nullm_flags; }; #ifdef _KERNEL /* * A cache of vnode references */ struct null_node { LIST_ENTRY(null_node) null_hash; /* Hash list */ struct vnode *null_lowervp; /* VREFed once */ struct vnode *null_vnode; /* Back pointer */ u_int null_flags; }; #define NULLV_NOUNLOCK 0x0001 #define NULLV_DROP 0x0002 #define MOUNTTONULLMOUNT(mp) ((struct null_mount *)((mp)->mnt_data)) #define VTONULL(vp) ((struct null_node *)(vp)->v_data) #define NULLTOV(xp) ((xp)->null_vnode) int nullfs_init(struct vfsconf *vfsp); int nullfs_uninit(struct vfsconf *vfsp); int null_nodeget(struct mount *mp, struct vnode *target, struct vnode **vpp); struct vnode *null_hashget(struct mount *mp, struct vnode *lowervp); void null_hashrem(struct null_node *xp); int null_bypass(struct vop_generic_args *ap); #ifdef DIAGNOSTIC struct vnode *null_checkvp(struct vnode *vp, char *fil, int lno); #define NULLVPTOLOWERVP(vp) null_checkvp((vp), __FILE__, __LINE__) #else #define NULLVPTOLOWERVP(vp) (VTONULL(vp)->null_lowervp) #endif extern struct vop_vector null_vnodeops; #ifdef MALLOC_DECLARE MALLOC_DECLARE(M_NULLFSNODE); #endif #ifdef NULLFS_DEBUG #define NULLFSDEBUG(format, args...) printf(format ,## args) #else #define NULLFSDEBUG(format, args...) #endif /* NULLFS_DEBUG */ #endif /* _KERNEL */ #endif Index: head/sys/fs/nullfs/null_subr.c =================================================================== --- head/sys/fs/nullfs/null_subr.c (revision 357198) +++ head/sys/fs/nullfs/null_subr.c (revision 357199) @@ -1,323 +1,325 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1992, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software donated to Berkeley by * Jan-Simon Pendry. * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)null_subr.c 8.7 (Berkeley) 5/14/95 * * $FreeBSD$ */ #include #include #include #include #include #include #include #include #include #include /* * Null layer cache: * Each cache entry holds a reference to the lower vnode * along with a pointer to the alias vnode. When an * entry is added the lower vnode is VREF'd. When the * alias is removed the lower vnode is vrele'd. */ #define NULL_NHASH(vp) (&null_node_hashtbl[vfs_hash_index(vp) & null_hash_mask]) static LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl; static struct rwlock null_hash_lock; static u_long null_hash_mask; static MALLOC_DEFINE(M_NULLFSHASH, "nullfs_hash", "NULLFS hash table"); MALLOC_DEFINE(M_NULLFSNODE, "nullfs_node", "NULLFS vnode private part"); static struct vnode * null_hashins(struct mount *, struct null_node *); /* * Initialise cache headers */ int nullfs_init(vfsp) struct vfsconf *vfsp; { null_node_hashtbl = hashinit(desiredvnodes, M_NULLFSHASH, &null_hash_mask); rw_init(&null_hash_lock, "nullhs"); return (0); } int nullfs_uninit(vfsp) struct vfsconf *vfsp; { rw_destroy(&null_hash_lock); hashdestroy(null_node_hashtbl, M_NULLFSHASH, null_hash_mask); return (0); } /* * Return a VREF'ed alias for lower vnode if already exists, else 0. * Lower vnode should be locked on entry and will be left locked on exit. */ struct vnode * null_hashget(mp, lowervp) struct mount *mp; struct vnode *lowervp; { struct null_node_hashhead *hd; struct null_node *a; struct vnode *vp; ASSERT_VOP_LOCKED(lowervp, "null_hashget"); /* * Find hash base, and then search the (two-way) linked * list looking for a null_node structure which is referencing * the lower vnode. If found, the increment the null_node * reference count (but NOT the lower vnode's VREF counter). */ hd = NULL_NHASH(lowervp); if (LIST_EMPTY(hd)) return (NULLVP); rw_rlock(&null_hash_lock); LIST_FOREACH(a, hd, null_hash) { if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) { /* * Since we have the lower node locked the nullfs * node can not be in the process of recycling. If * it had been recycled before we grabed the lower * lock it would not have been found on the hash. */ vp = NULLTOV(a); vref(vp); rw_runlock(&null_hash_lock); return (vp); } } rw_runlock(&null_hash_lock); return (NULLVP); } /* * Act like null_hashget, but add passed null_node to hash if no existing * node found. */ static struct vnode * null_hashins(mp, xp) struct mount *mp; struct null_node *xp; { struct null_node_hashhead *hd; struct null_node *oxp; struct vnode *ovp; hd = NULL_NHASH(xp->null_lowervp); rw_wlock(&null_hash_lock); LIST_FOREACH(oxp, hd, null_hash) { if (oxp->null_lowervp == xp->null_lowervp && NULLTOV(oxp)->v_mount == mp) { /* * See null_hashget for a description of this * operation. */ ovp = NULLTOV(oxp); vref(ovp); rw_wunlock(&null_hash_lock); return (ovp); } } LIST_INSERT_HEAD(hd, xp, null_hash); rw_wunlock(&null_hash_lock); return (NULLVP); } static void null_destroy_proto(struct vnode *vp, void *xp) { lockmgr(&vp->v_lock, LK_EXCLUSIVE, NULL); VI_LOCK(vp); vp->v_data = NULL; vp->v_vnlock = &vp->v_lock; vp->v_op = &dead_vnodeops; VI_UNLOCK(vp); vgone(vp); vput(vp); free(xp, M_NULLFSNODE); } static void null_insmntque_dtr(struct vnode *vp, void *xp) { vput(((struct null_node *)xp)->null_lowervp); null_destroy_proto(vp, xp); } /* * Make a new or get existing nullfs node. * Vp is the alias vnode, lowervp is the lower vnode. * * The lowervp assumed to be locked and having "spare" reference. This routine * vrele lowervp if nullfs node was taken from hash. Otherwise it "transfers" * the caller's "spare" reference to created nullfs vnode. */ int null_nodeget(mp, lowervp, vpp) struct mount *mp; struct vnode *lowervp; struct vnode **vpp; { struct null_node *xp; struct vnode *vp; int error; ASSERT_VOP_LOCKED(lowervp, "lowervp"); KASSERT(lowervp->v_usecount >= 1, ("Unreferenced vnode %p", lowervp)); /* Lookup the hash firstly. */ *vpp = null_hashget(mp, lowervp); if (*vpp != NULL) { vrele(lowervp); return (0); } /* * The insmntque1() call below requires the exclusive lock on * the nullfs vnode. Upgrade the lock now if hash failed to * provide ready to use vnode. */ if (VOP_ISLOCKED(lowervp) != LK_EXCLUSIVE) { vn_lock(lowervp, LK_UPGRADE | LK_RETRY); if (VN_IS_DOOMED(lowervp)) { vput(lowervp); return (ENOENT); } } /* * We do not serialize vnode creation, instead we will check for * duplicates later, when adding new vnode to hash. * Note that duplicate can only appear in hash if the lowervp is * locked LK_SHARED. */ xp = malloc(sizeof(struct null_node), M_NULLFSNODE, M_WAITOK); error = getnewvnode("nullfs", mp, &null_vnodeops, &vp); if (error) { vput(lowervp); free(xp, M_NULLFSNODE); return (error); } xp->null_vnode = vp; xp->null_lowervp = lowervp; xp->null_flags = 0; vp->v_type = lowervp->v_type; vp->v_data = xp; vp->v_vnlock = lowervp->v_vnlock; + if (lowervp == MOUNTTONULLMOUNT(mp)->nullm_lowerrootvp) + vp->v_vflag |= VV_ROOT; error = insmntque1(vp, mp, null_insmntque_dtr, xp); if (error != 0) return (error); /* * Atomically insert our new node into the hash or vget existing * if someone else has beaten us to it. */ *vpp = null_hashins(mp, xp); if (*vpp != NULL) { vrele(lowervp); null_destroy_proto(vp, xp); return (0); } *vpp = vp; return (0); } /* * Remove node from hash. */ void null_hashrem(xp) struct null_node *xp; { rw_wlock(&null_hash_lock); LIST_REMOVE(xp, null_hash); rw_wunlock(&null_hash_lock); } #ifdef DIAGNOSTIC struct vnode * null_checkvp(vp, fil, lno) struct vnode *vp; char *fil; int lno; { struct null_node *a = VTONULL(vp); #ifdef notyet /* * Can't do this check because vop_reclaim runs * with a funny vop vector. */ if (vp->v_op != null_vnodeop_p) { printf ("null_checkvp: on non-null-node\n"); panic("null_checkvp"); } #endif if (a->null_lowervp == NULLVP) { /* Should never happen */ panic("null_checkvp %p", vp); } VI_LOCK_FLAGS(a->null_lowervp, MTX_DUPOK); if (a->null_lowervp->v_usecount < 1) panic ("null with unref'ed lowervp, vp %p lvp %p", vp, a->null_lowervp); VI_UNLOCK(a->null_lowervp); #ifdef notyet printf("null %x/%d -> %x/%d [%s, %d]\n", NULLTOV(a), vrefcnt(NULLTOV(a)), a->null_lowervp, vrefcnt(a->null_lowervp), fil, lno); #endif return (a->null_lowervp); } #endif Index: head/sys/fs/nullfs/null_vfsops.c =================================================================== --- head/sys/fs/nullfs/null_vfsops.c (revision 357198) +++ head/sys/fs/nullfs/null_vfsops.c (revision 357199) @@ -1,479 +1,471 @@ /*- * SPDX-License-Identifier: BSD-3-Clause * * Copyright (c) 1992, 1993, 1995 * The Regents of the University of California. All rights reserved. * * This code is derived from software donated to Berkeley by * Jan-Simon Pendry. * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94 * * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92 * $FreeBSD$ */ /* * Null Layer * (See null_vnops.c for a description of what this does.) */ #include #include #include #include #include #include #include #include #include #include #include #include static MALLOC_DEFINE(M_NULLFSMNT, "nullfs_mount", "NULLFS mount structure"); static vfs_fhtovp_t nullfs_fhtovp; static vfs_mount_t nullfs_mount; static vfs_quotactl_t nullfs_quotactl; static vfs_root_t nullfs_root; static vfs_sync_t nullfs_sync; static vfs_statfs_t nullfs_statfs; static vfs_unmount_t nullfs_unmount; static vfs_vget_t nullfs_vget; static vfs_extattrctl_t nullfs_extattrctl; /* * Mount null layer */ static int nullfs_mount(struct mount *mp) { - struct vnode *lowerrootvp, *vp; + struct vnode *lowerrootvp; struct vnode *nullm_rootvp; struct null_mount *xmp; struct null_node *nn; struct nameidata nd, *ndp; char *target; int error, len; bool isvnunlocked; NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp); if (mp->mnt_flag & MNT_ROOTFS) return (EOPNOTSUPP); /* * Update is a no-op */ if (mp->mnt_flag & MNT_UPDATE) { /* * Only support update mounts for NFS export. */ if (vfs_flagopt(mp->mnt_optnew, "export", NULL, 0)) return (0); else return (EOPNOTSUPP); } /* * Get argument */ error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len); if (error || target[len - 1] != '\0') return (EINVAL); /* * Unlock lower node to avoid possible deadlock. */ if (mp->mnt_vnodecovered->v_op == &null_vnodeops && VOP_ISLOCKED(mp->mnt_vnodecovered) == LK_EXCLUSIVE) { VOP_UNLOCK(mp->mnt_vnodecovered); isvnunlocked = true; } else { isvnunlocked = false; } /* * Find lower node */ ndp = &nd; NDINIT(ndp, LOOKUP, FOLLOW|LOCKLEAF, UIO_SYSSPACE, target, curthread); error = namei(ndp); /* * Re-lock vnode. * XXXKIB This is deadlock-prone as well. */ if (isvnunlocked) vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY); if (error) return (error); NDFREE(ndp, NDF_ONLY_PNBUF); /* * Sanity check on lower vnode */ lowerrootvp = ndp->ni_vp; /* * Check multi null mount to avoid `lock against myself' panic. */ if (mp->mnt_vnodecovered->v_op == &null_vnodeops) { nn = VTONULL(mp->mnt_vnodecovered); if (nn == NULL || lowerrootvp == nn->null_lowervp) { NULLFSDEBUG("nullfs_mount: multi null mount?\n"); vput(lowerrootvp); return (EDEADLK); } } xmp = (struct null_mount *) malloc(sizeof(struct null_mount), M_NULLFSMNT, M_WAITOK | M_ZERO); /* - * Save reference to underlying FS + * Save pointer to underlying FS and the reference to the + * lower root vnode. */ xmp->nullm_vfs = lowerrootvp->v_mount; + vref(lowerrootvp); + xmp->nullm_lowerrootvp = lowerrootvp; + mp->mnt_data = xmp; /* - * Save reference. Each mount also holds - * a reference on the root vnode. + * Make sure the node alias worked. */ - error = null_nodeget(mp, lowerrootvp, &vp); - /* - * Make sure the node alias worked - */ - if (error) { + error = null_nodeget(mp, lowerrootvp, &nullm_rootvp); + if (error != 0) { + vrele(lowerrootvp); free(xmp, M_NULLFSMNT); return (error); } - /* - * Keep a held reference to the root vnode. - * It is vrele'd in nullfs_unmount. - */ - nullm_rootvp = vp; - nullm_rootvp->v_vflag |= VV_ROOT; - xmp->nullm_rootvp = nullm_rootvp; - - /* - * Unlock the node (either the lower or the alias) - */ - VOP_UNLOCK(vp); - if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL) { MNT_ILOCK(mp); mp->mnt_flag |= MNT_LOCAL; MNT_IUNLOCK(mp); } xmp->nullm_flags |= NULLM_CACHE; if (vfs_getopt(mp->mnt_optnew, "nocache", NULL, NULL) == 0 || (xmp->nullm_vfs->mnt_kern_flag & MNTK_NULL_NOCACHE) != 0) xmp->nullm_flags &= ~NULLM_CACHE; MNT_ILOCK(mp); if ((xmp->nullm_flags & NULLM_CACHE) != 0) { mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & (MNTK_SHARED_WRITES | MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED); } mp->mnt_kern_flag |= MNTK_LOOKUP_EXCL_DOTDOT | MNTK_NOMSYNC; mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag & (MNTK_USES_BCACHE | MNTK_NO_IOPF | MNTK_UNMAPPED_BUFS); MNT_IUNLOCK(mp); - mp->mnt_data = xmp; vfs_getnewfsid(mp); if ((xmp->nullm_flags & NULLM_CACHE) != 0) { MNT_ILOCK(xmp->nullm_vfs); TAILQ_INSERT_TAIL(&xmp->nullm_vfs->mnt_uppers, mp, mnt_upper_link); MNT_IUNLOCK(xmp->nullm_vfs); } vfs_mountedfrom(mp, target); + vput(nullm_rootvp); NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n", mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname); return (0); } /* * Free reference to null layer */ static int nullfs_unmount(mp, mntflags) struct mount *mp; int mntflags; { struct null_mount *mntdata; struct mount *ump; - int error, flags, rootrefs; + int error, flags; NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp); if (mntflags & MNT_FORCE) flags = FORCECLOSE; else flags = 0; - for (rootrefs = 1;; rootrefs = 0) { + for (;;) { /* There is 1 extra root vnode reference (nullm_rootvp). */ - error = vflush(mp, rootrefs, flags, curthread); + error = vflush(mp, 0, flags, curthread); if (error) return (error); MNT_ILOCK(mp); if (mp->mnt_nvnodelistsize == 0) { MNT_IUNLOCK(mp); break; } MNT_IUNLOCK(mp); if ((mntflags & MNT_FORCE) == 0) return (EBUSY); } /* * Finally, throw away the null_mount structure */ mntdata = mp->mnt_data; ump = mntdata->nullm_vfs; if ((mntdata->nullm_flags & NULLM_CACHE) != 0) { MNT_ILOCK(ump); while ((ump->mnt_kern_flag & MNTK_VGONE_UPPER) != 0) { ump->mnt_kern_flag |= MNTK_VGONE_WAITER; msleep(&ump->mnt_uppers, &ump->mnt_mtx, 0, "vgnupw", 0); } TAILQ_REMOVE(&ump->mnt_uppers, mp, mnt_upper_link); MNT_IUNLOCK(ump); } + vrele(mntdata->nullm_lowerrootvp); mp->mnt_data = NULL; free(mntdata, M_NULLFSMNT); return (0); } static int nullfs_root(mp, flags, vpp) struct mount *mp; int flags; struct vnode **vpp; { struct vnode *vp; + struct null_mount *mntdata; + int error; - NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp, - (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, - (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); + mntdata = MOUNTTONULLMOUNT(mp); + NULLFSDEBUG("nullfs_root(mp = %p, vp = %p)\n", mp, + mntdata->nullm_lowerrootvp); - /* - * Return locked reference to root. - */ - vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp; - VREF(vp); - - ASSERT_VOP_UNLOCKED(vp, "root vnode is locked"); - vn_lock(vp, flags | LK_RETRY); - *vpp = vp; - return 0; + error = vget(mntdata->nullm_lowerrootvp, (flags & ~LK_TYPE_MASK) | + LK_EXCLUSIVE, curthread); + if (error == 0) { + error = null_nodeget(mp, mntdata->nullm_lowerrootvp, &vp); + if (error == 0) { + if ((flags & LK_TYPE_MASK) == LK_SHARED) + vn_lock(vp, LK_DOWNGRADE | LK_RETRY); + *vpp = vp; + } + } + return (error); } static int nullfs_quotactl(mp, cmd, uid, arg) struct mount *mp; int cmd; uid_t uid; void *arg; { return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg); } static int nullfs_statfs(mp, sbp) struct mount *mp; struct statfs *sbp; { int error; struct statfs *mstat; NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp, (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp, (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)); mstat = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK | M_ZERO); error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, mstat); if (error) { free(mstat, M_STATFS); return (error); } /* now copy across the "interesting" information and fake the rest */ sbp->f_type = mstat->f_type; sbp->f_flags = (sbp->f_flags & (MNT_RDONLY | MNT_NOEXEC | MNT_NOSUID | MNT_UNION | MNT_NOSYMFOLLOW | MNT_AUTOMOUNTED)) | (mstat->f_flags & ~(MNT_ROOTFS | MNT_AUTOMOUNTED)); sbp->f_bsize = mstat->f_bsize; sbp->f_iosize = mstat->f_iosize; sbp->f_blocks = mstat->f_blocks; sbp->f_bfree = mstat->f_bfree; sbp->f_bavail = mstat->f_bavail; sbp->f_files = mstat->f_files; sbp->f_ffree = mstat->f_ffree; free(mstat, M_STATFS); return (0); } static int nullfs_sync(mp, waitfor) struct mount *mp; int waitfor; { /* * XXX - Assumes no data cached at null layer. */ return (0); } static int nullfs_vget(mp, ino, flags, vpp) struct mount *mp; ino_t ino; int flags; struct vnode **vpp; { int error; KASSERT((flags & LK_TYPE_MASK) != 0, ("nullfs_vget: no lock requested")); error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp); if (error != 0) return (error); return (null_nodeget(mp, *vpp, vpp)); } static int nullfs_fhtovp(mp, fidp, flags, vpp) struct mount *mp; struct fid *fidp; int flags; struct vnode **vpp; { int error; error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, flags, vpp); if (error != 0) return (error); return (null_nodeget(mp, *vpp, vpp)); } static int nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname) struct mount *mp; int cmd; struct vnode *filename_vp; int namespace; const char *attrname; { return (VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp, namespace, attrname)); } static void nullfs_reclaim_lowervp(struct mount *mp, struct vnode *lowervp) { struct vnode *vp; vp = null_hashget(mp, lowervp); if (vp == NULL) return; VTONULL(vp)->null_flags |= NULLV_NOUNLOCK; vgone(vp); vput(vp); } static void nullfs_unlink_lowervp(struct mount *mp, struct vnode *lowervp) { struct vnode *vp; struct null_node *xp; vp = null_hashget(mp, lowervp); if (vp == NULL) return; xp = VTONULL(vp); xp->null_flags |= NULLV_DROP | NULLV_NOUNLOCK; vhold(vp); vunref(vp); if (vp->v_usecount == 0) { /* * If vunref() dropped the last use reference on the * nullfs vnode, it must be reclaimed, and its lock * was split from the lower vnode lock. Need to do * extra unlock before allowing the final vdrop() to * free the vnode. */ KASSERT(VN_IS_DOOMED(vp), ("not reclaimed nullfs vnode %p", vp)); VOP_UNLOCK(vp); } else { /* * Otherwise, the nullfs vnode still shares the lock * with the lower vnode, and must not be unlocked. * Also clear the NULLV_NOUNLOCK, the flag is not * relevant for future reclamations. */ ASSERT_VOP_ELOCKED(vp, "unlink_lowervp"); KASSERT(!VN_IS_DOOMED(vp), ("reclaimed nullfs vnode %p", vp)); xp->null_flags &= ~NULLV_NOUNLOCK; } vdrop(vp); } static struct vfsops null_vfsops = { .vfs_extattrctl = nullfs_extattrctl, .vfs_fhtovp = nullfs_fhtovp, .vfs_init = nullfs_init, .vfs_mount = nullfs_mount, .vfs_quotactl = nullfs_quotactl, .vfs_root = nullfs_root, .vfs_statfs = nullfs_statfs, .vfs_sync = nullfs_sync, .vfs_uninit = nullfs_uninit, .vfs_unmount = nullfs_unmount, .vfs_vget = nullfs_vget, .vfs_reclaim_lowervp = nullfs_reclaim_lowervp, .vfs_unlink_lowervp = nullfs_unlink_lowervp, }; VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK | VFCF_JAIL);