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usr.sbin/bhyve/block_backends.c

  • This file was copied from usr.sbin/bhyve/block_if.c.
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#include <pthread.h> #include <pthread.h>
#include <pthread_np.h> #include <pthread_np.h>
#include <signal.h> #include <signal.h>
#include <sysexits.h> #include <sysexits.h>
#include <unistd.h> #include <unistd.h>
#include <machine/atomic.h> #include <machine/atomic.h>
#include <sys/linker_set.h>
#include "bhyverun.h" #include "bhyverun.h"
#include "debug.h" #include "debug.h"
#include "mevent.h" #include "mevent.h"
#include "block_if.h" #include "block_backends.h"
#define BLOCKIF_SIG 0xb109b109 SET_DECLARE(block_backend_set, block_backend_t);
#define BLOCKIF_NUMTHR 8
#define BLOCKIF_MAXREQ (BLOCKIF_RING_MAX + BLOCKIF_NUMTHR)
enum blockop {
BOP_READ,
BOP_WRITE,
BOP_FLUSH,
BOP_DELETE
};
enum blockstat {
BST_FREE,
BST_BLOCK,
BST_PEND,
BST_BUSY,
BST_DONE
};
struct blockif_elem {
TAILQ_ENTRY(blockif_elem) be_link;
struct blockif_req *be_req;
enum blockop be_op;
enum blockstat be_status;
pthread_t be_tid;
off_t be_block;
};
struct blockif_ctxt {
int bc_magic;
int bc_fd;
int bc_ischr;
int bc_isgeom;
int bc_candelete;
int bc_rdonly;
off_t bc_size;
int bc_sectsz;
int bc_psectsz;
int bc_psectoff;
int bc_closing;
pthread_t bc_btid[BLOCKIF_NUMTHR];
pthread_mutex_t bc_mtx;
pthread_cond_t bc_cond;
/* Request elements and free/pending/busy queues */
TAILQ_HEAD(, blockif_elem) bc_freeq;
TAILQ_HEAD(, blockif_elem) bc_pendq;
TAILQ_HEAD(, blockif_elem) bc_busyq;
struct blockif_elem bc_reqs[BLOCKIF_MAXREQ];
};
static pthread_once_t blockif_once = PTHREAD_ONCE_INIT;
struct blockif_sig_elem {
pthread_mutex_t bse_mtx;
pthread_cond_t bse_cond;
int bse_pending;
struct blockif_sig_elem *bse_next;
};
static struct blockif_sig_elem *blockif_bse_head;
static int
blockif_enqueue(struct blockif_ctxt *bc, struct blockif_req *breq,
enum blockop op)
{
struct blockif_elem *be, *tbe;
off_t off;
int i;
be = TAILQ_FIRST(&bc->bc_freeq);
assert(be != NULL);
assert(be->be_status == BST_FREE);
TAILQ_REMOVE(&bc->bc_freeq, be, be_link);
be->be_req = breq;
be->be_op = op;
switch (op) {
case BOP_READ:
case BOP_WRITE:
case BOP_DELETE:
off = breq->br_offset;
for (i = 0; i < breq->br_iovcnt; i++)
off += breq->br_iov[i].iov_len;
break;
default:
off = OFF_MAX;
}
be->be_block = off;
TAILQ_FOREACH(tbe, &bc->bc_pendq, be_link) {
if (tbe->be_block == breq->br_offset)
break;
}
if (tbe == NULL) {
TAILQ_FOREACH(tbe, &bc->bc_busyq, be_link) {
if (tbe->be_block == breq->br_offset)
break;
}
}
if (tbe == NULL)
be->be_status = BST_PEND;
else
be->be_status = BST_BLOCK;
TAILQ_INSERT_TAIL(&bc->bc_pendq, be, be_link);
return (be->be_status == BST_PEND);
}
static int
blockif_dequeue(struct blockif_ctxt *bc, pthread_t t, struct blockif_elem **bep)
{
struct blockif_elem *be;
TAILQ_FOREACH(be, &bc->bc_pendq, be_link) {
if (be->be_status == BST_PEND)
break;
assert(be->be_status == BST_BLOCK);
}
if (be == NULL)
return (0);
TAILQ_REMOVE(&bc->bc_pendq, be, be_link);
be->be_status = BST_BUSY;
be->be_tid = t;
TAILQ_INSERT_TAIL(&bc->bc_busyq, be, be_link);
*bep = be;
return (1);
}
static void
blockif_complete(struct blockif_ctxt *bc, struct blockif_elem *be)
{
struct blockif_elem *tbe;
if (be->be_status == BST_DONE || be->be_status == BST_BUSY)
TAILQ_REMOVE(&bc->bc_busyq, be, be_link);
else
TAILQ_REMOVE(&bc->bc_pendq, be, be_link);
TAILQ_FOREACH(tbe, &bc->bc_pendq, be_link) {
if (tbe->be_req->br_offset == be->be_block)
tbe->be_status = BST_PEND;
}
be->be_tid = 0;
be->be_status = BST_FREE;
be->be_req = NULL;
TAILQ_INSERT_TAIL(&bc->bc_freeq, be, be_link);
}
static void
blockif_proc(struct blockif_ctxt *bc, struct blockif_elem *be, uint8_t *buf)
{
struct blockif_req *br;
off_t arg[2];
ssize_t clen, len, off, boff, voff;
int i, err;
br = be->be_req;
if (br->br_iovcnt <= 1)
buf = NULL;
err = 0;
switch (be->be_op) {
case BOP_READ:
if (buf == NULL) {
if ((len = preadv(bc->bc_fd, br->br_iov, br->br_iovcnt,
br->br_offset)) < 0)
err = errno;
else
br->br_resid -= len;
break;
}
i = 0;
off = voff = 0;
while (br->br_resid > 0) {
len = MIN(br->br_resid, MAXPHYS);
if (pread(bc->bc_fd, buf, len, br->br_offset +
off) < 0) {
err = errno;
break;
}
boff = 0;
do {
clen = MIN(len - boff, br->br_iov[i].iov_len -
voff);
memcpy(br->br_iov[i].iov_base + voff,
buf + boff, clen);
if (clen < br->br_iov[i].iov_len - voff)
voff += clen;
else {
i++;
voff = 0;
}
boff += clen;
} while (boff < len);
off += len;
br->br_resid -= len;
}
break;
case BOP_WRITE:
if (bc->bc_rdonly) {
err = EROFS;
break;
}
if (buf == NULL) {
if ((len = pwritev(bc->bc_fd, br->br_iov, br->br_iovcnt,
br->br_offset)) < 0)
err = errno;
else
br->br_resid -= len;
break;
}
i = 0;
off = voff = 0;
while (br->br_resid > 0) {
len = MIN(br->br_resid, MAXPHYS);
boff = 0;
do {
clen = MIN(len - boff, br->br_iov[i].iov_len -
voff);
memcpy(buf + boff,
br->br_iov[i].iov_base + voff, clen);
if (clen < br->br_iov[i].iov_len - voff)
voff += clen;
else {
i++;
voff = 0;
}
boff += clen;
} while (boff < len);
if (pwrite(bc->bc_fd, buf, len, br->br_offset +
off) < 0) {
err = errno;
break;
}
off += len;
br->br_resid -= len;
}
break;
case BOP_FLUSH:
if (bc->bc_ischr) {
if (ioctl(bc->bc_fd, DIOCGFLUSH))
err = errno;
} else if (fsync(bc->bc_fd))
err = errno;
break;
case BOP_DELETE:
if (!bc->bc_candelete)
err = EOPNOTSUPP;
else if (bc->bc_rdonly)
err = EROFS;
else if (bc->bc_ischr) {
arg[0] = br->br_offset;
arg[1] = br->br_resid;
if (ioctl(bc->bc_fd, DIOCGDELETE, arg))
err = errno;
else
br->br_resid = 0;
} else
err = EOPNOTSUPP;
break;
default:
err = EINVAL;
break;
}
be->be_status = BST_DONE;
(*br->br_callback)(br, err);
}
static void *
blockif_thr(void *arg)
{
struct blockif_ctxt *bc;
struct blockif_elem *be;
pthread_t t;
uint8_t *buf;
bc = arg;
if (bc->bc_isgeom)
buf = malloc(MAXPHYS);
else
buf = NULL;
t = pthread_self();
pthread_mutex_lock(&bc->bc_mtx);
for (;;) {
while (blockif_dequeue(bc, t, &be)) {
pthread_mutex_unlock(&bc->bc_mtx);
blockif_proc(bc, be, buf);
pthread_mutex_lock(&bc->bc_mtx);
blockif_complete(bc, be);
}
/* Check ctxt status here to see if exit requested */
if (bc->bc_closing)
break;
pthread_cond_wait(&bc->bc_cond, &bc->bc_mtx);
}
pthread_mutex_unlock(&bc->bc_mtx);
if (buf)
free(buf);
pthread_exit(NULL);
return (NULL);
}
static void
blockif_sigcont_handler(int signal, enum ev_type type, void *arg)
{
struct blockif_sig_elem *bse;
for (;;) {
/* /*
* Process the entire list even if not intended for * Initialize a backend and attach to the frontend.
* this thread. * This is called during frontend initialization.
* @pbe is a pointer to the backend to be initialized
* @devname is the backend-name as supplied on the command line,
* e.g. -s 2:0,frontend-name,backend-name[,other-args]
* @cb is the receive callback supplied by the frontend,
* and it is invoked in the event loop when a receive
* event is generated in the hypervisor,
* @param is a pointer to the frontend, and normally used as
* the argument for the callback.
*/ */
do { int
bse = blockif_bse_head; blockbe_open(block_backend_t **ret, const char *optstr,
if (bse == NULL) const char *pci_ident);
return;
} while (!atomic_cmpset_ptr((uintptr_t *)&blockif_bse_head,
(uintptr_t)bse,
(uintptr_t)bse->bse_next));
pthread_mutex_lock(&bse->bse_mtx);
bse->bse_pending = 0;
pthread_cond_signal(&bse->bse_cond);
pthread_mutex_unlock(&bse->bse_mtx);
}
}
static void
blockif_init(void)
{ {
mevent_add(SIGCONT, EVF_SIGNAL, blockif_sigcont_handler, NULL); block_backend_t **bbe = NULL;
(void) signal(SIGCONT, SIG_IGN); int err;
} *ret = NULL;
struct blockif_ctxt *
blockif_open(const char *optstr, const char *ident)
{
char tname[MAXCOMLEN + 1];
char name[MAXPATHLEN];
char *nopt, *xopts, *cp;
struct blockif_ctxt *bc;
struct stat sbuf;
struct diocgattr_arg arg;
off_t size, psectsz, psectoff;
int extra, fd, i, sectsz;
int nocache, sync, ro, candelete, geom, ssopt, pssopt;
#ifndef WITHOUT_CAPSICUM
cap_rights_t rights;
cap_ioctl_t cmds[] = { DIOCGFLUSH, DIOCGDELETE };
#endif
pthread_once(&blockif_once, blockif_init);
fd = -1;
ssopt = 0;
nocache = 0;
sync = 0;
ro = 0;
/* /*
* The first element in the optstring is always a pathname. * Find the block device backend that matches the user-provided
* Optional elements follow * device name. block_backend_set is built using a linker set.
*/ */
nopt = xopts = strdup(optstr); SET_FOREACH(bbe, block_backend_set) {
while (xopts != NULL) {
cp = strsep(&xopts, ",");
if (cp == nopt) /* file or device pathname */
continue;
else if (!strcmp(cp, "nocache"))
nocache = 1;
else if (!strcmp(cp, "sync") || !strcmp(cp, "direct"))
sync = 1;
else if (!strcmp(cp, "ro"))
ro = 1;
else if (sscanf(cp, "sectorsize=%d/%d", &ssopt, &pssopt) == 2)
;
else if (sscanf(cp, "sectorsize=%d", &ssopt) == 1)
pssopt = ssopt;
else {
EPRINTLN("Invalid device option \"%s\"", cp);
goto err;
}
}
extra = 0;
if (nocache)
extra |= O_DIRECT;
if (sync)
extra |= O_SYNC;
fd = open(nopt, (ro ? O_RDONLY : O_RDWR) | extra);
if (fd < 0 && !ro) {
/* Attempt a r/w fail with a r/o open */
fd = open(nopt, O_RDONLY | extra);
ro = 1;
}
if (fd < 0) {
warn("Could not open backing file: %s", nopt);
goto err;
}
if (fstat(fd, &sbuf) < 0) {
warn("Could not stat backing file %s", nopt);
goto err;
}
#ifndef WITHOUT_CAPSICUM
cap_rights_init(&rights, CAP_FSYNC, CAP_IOCTL, CAP_READ, CAP_SEEK,
CAP_WRITE);
if (ro)
cap_rights_clear(&rights, CAP_FSYNC, CAP_WRITE);
if (caph_rights_limit(fd, &rights) == -1)
errx(EX_OSERR, "Unable to apply rights for sandbox");
#endif
/* /*
* Deal with raw devices * How do we find the appropriate open for each backend?
* We should itterate over all block_open() functions until one
* returns true as an indication that it accepts the give descriptor
* in opstr
*/ */
size = sbuf.st_size;
sectsz = DEV_BSIZE;
psectsz = psectoff = 0;
candelete = geom = 0;
if (S_ISCHR(sbuf.st_mode)) {
if (ioctl(fd, DIOCGMEDIASIZE, &size) < 0 ||
ioctl(fd, DIOCGSECTORSIZE, &sectsz)) {
perror("Could not fetch dev blk/sector size");
goto err;
}
assert(size != 0);
assert(sectsz != 0);
if (ioctl(fd, DIOCGSTRIPESIZE, &psectsz) == 0 && psectsz > 0)
ioctl(fd, DIOCGSTRIPEOFFSET, &psectoff);
strlcpy(arg.name, "GEOM::candelete", sizeof(arg.name));
arg.len = sizeof(arg.value.i);
if (ioctl(fd, DIOCGATTR, &arg) == 0)
candelete = arg.value.i;
if (ioctl(fd, DIOCGPROVIDERNAME, name) == 0)
geom = 1;
} else
psectsz = sbuf.st_blksize;
#ifndef WITHOUT_CAPSICUM
if (caph_ioctls_limit(fd, cmds, nitems(cmds)) == -1)
errx(EX_OSERR, "Unable to apply rights for sandbox");
#endif
if (ssopt != 0) {
if (!powerof2(ssopt) || !powerof2(pssopt) || ssopt < 512 ||
ssopt > pssopt) {
EPRINTLN("Invalid sector size %d/%d",
ssopt, pssopt);
goto err;
}
/* /*
* Some backend drivers (e.g. cd0, ada0) require that the I/O * Local access has a pattern like:
* size be a multiple of the device's sector size. * 3:0,virtio-blk,file/somewhere/guest.img
* 3:0,virtio-blk,/dev/xxxx
* The file part should be in optstr so we check if optstr exists as a file
* in which case it would be access to the local filesystem.
* This is handled by the blk-local backend.
* If this does not match then other backends in the block_backend_set have
* their open() called. The first one returning 0 is a match and is used
* with the specification in optstr
* *
* Validate that the emulated sector size complies with this
* requirement.
*/ */
if (S_ISCHR(sbuf.st_mode)) { if ((err = (*bbe)->open(ret, optstr, pci_ident, be_ident)) == 0) {
if (ssopt < sectsz || (ssopt % sectsz) != 0) { break;
EPRINTLN("Sector size %d incompatible "
"with underlying device sector size %d",
ssopt, sectsz);
goto err;
} }
} }
return err;
sectsz = ssopt;
psectsz = pssopt;
psectoff = 0;
} }
bc = calloc(1, sizeof(struct blockif_ctxt)); off_t
if (bc == NULL) { blockbe_size(block_backend_t *be)
perror("calloc"); {
goto err; assert(be != NULL);
return (be->size(be));
} }
bc->bc_magic = BLOCKIF_SIG; void
bc->bc_fd = fd; blockbe_chs(block_backend_t *be, uint16_t *c, uint8_t *h,
bc->bc_ischr = S_ISCHR(sbuf.st_mode); uint8_t *s)
bc->bc_isgeom = geom;
bc->bc_candelete = candelete;
bc->bc_rdonly = ro;
bc->bc_size = size;
bc->bc_sectsz = sectsz;
bc->bc_psectsz = psectsz;
bc->bc_psectoff = psectoff;
pthread_mutex_init(&bc->bc_mtx, NULL);
pthread_cond_init(&bc->bc_cond, NULL);
TAILQ_INIT(&bc->bc_freeq);
TAILQ_INIT(&bc->bc_pendq);
TAILQ_INIT(&bc->bc_busyq);
for (i = 0; i < BLOCKIF_MAXREQ; i++) {
bc->bc_reqs[i].be_status = BST_FREE;
TAILQ_INSERT_HEAD(&bc->bc_freeq, &bc->bc_reqs[i], be_link);
}
for (i = 0; i < BLOCKIF_NUMTHR; i++) {
pthread_create(&bc->bc_btid[i], NULL, blockif_thr, bc);
snprintf(tname, sizeof(tname), "blk-%s-%d", ident, i);
pthread_set_name_np(bc->bc_btid[i], tname);
}
return (bc);
err:
if (fd >= 0)
close(fd);
free(nopt);
return (NULL);
}
static int
blockif_request(struct blockif_ctxt *bc, struct blockif_req *breq,
enum blockop op)
{ {
int err; assert(be != NULL);
(be->chs(be, c, h, s));
err = 0;
pthread_mutex_lock(&bc->bc_mtx);
if (!TAILQ_EMPTY(&bc->bc_freeq)) {
/*
* Enqueue and inform the block i/o thread
* that there is work available
*/
if (blockif_enqueue(bc, breq, op))
pthread_cond_signal(&bc->bc_cond);
} else {
/*
* Callers are not allowed to enqueue more than
* the specified blockif queue limit. Return an
* error to indicate that the queue length has been
* exceeded.
*/
err = E2BIG;
} }
pthread_mutex_unlock(&bc->bc_mtx);
return (err);
}
int int
blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq) blockbe_sectsz(block_backend_t *be)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->sectsz(be));
return (blockif_request(bc, breq, BOP_READ));
} }
int void
blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq) blockbe_psectsz(block_backend_t *be, int *size, int *off)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->psectsz(be, size, off));
return (blockif_request(bc, breq, BOP_WRITE));
} }
int int
blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq) blockbe_queuesz(block_backend_t *be)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->queuesz(be));
return (blockif_request(bc, breq, BOP_FLUSH));
} }
int int
blockif_delete(struct blockif_ctxt *bc, struct blockif_req *breq) blockbe_is_ro(block_backend_t *be)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->is_ro(be));
return (blockif_request(bc, breq, BOP_DELETE));
} }
int int
blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq) blockbe_candelete(block_backend_t *be)
{ {
struct blockif_elem *be; assert(be != NULL);
return (be->candelete(be));
assert(bc->bc_magic == BLOCKIF_SIG);
pthread_mutex_lock(&bc->bc_mtx);
/*
* Check pending requests.
*/
TAILQ_FOREACH(be, &bc->bc_pendq, be_link) {
if (be->be_req == breq)
break;
} }
if (be != NULL) {
/*
* Found it.
*/
blockif_complete(bc, be);
pthread_mutex_unlock(&bc->bc_mtx);
return (0);
}
/*
* Check in-flight requests.
*/
TAILQ_FOREACH(be, &bc->bc_busyq, be_link) {
if (be->be_req == breq)
break;
}
if (be == NULL) {
/*
* Didn't find it.
*/
pthread_mutex_unlock(&bc->bc_mtx);
return (EINVAL);
}
/*
* Interrupt the processing thread to force it return
* prematurely via it's normal callback path.
*/
while (be->be_status == BST_BUSY) {
struct blockif_sig_elem bse, *old_head;
pthread_mutex_init(&bse.bse_mtx, NULL);
pthread_cond_init(&bse.bse_cond, NULL);
bse.bse_pending = 1;
do {
old_head = blockif_bse_head;
bse.bse_next = old_head;
} while (!atomic_cmpset_ptr((uintptr_t *)&blockif_bse_head,
(uintptr_t)old_head,
(uintptr_t)&bse));
pthread_kill(be->be_tid, SIGCONT);
pthread_mutex_lock(&bse.bse_mtx);
while (bse.bse_pending)
pthread_cond_wait(&bse.bse_cond, &bse.bse_mtx);
pthread_mutex_unlock(&bse.bse_mtx);
}
pthread_mutex_unlock(&bc->bc_mtx);
/*
* The processing thread has been interrupted. Since it's not
* clear if the callback has been invoked yet, return EBUSY.
*/
return (EBUSY);
}
int int
blockif_close(struct blockif_ctxt *bc) blockbe_read(block_backend_t *be, struct blockif_req *breq)
{ {
void *jval; assert(be != NULL);
int i; return (be->read(be, breq));
assert(bc->bc_magic == BLOCKIF_SIG);
/*
* Stop the block i/o thread
*/
pthread_mutex_lock(&bc->bc_mtx);
bc->bc_closing = 1;
pthread_mutex_unlock(&bc->bc_mtx);
pthread_cond_broadcast(&bc->bc_cond);
for (i = 0; i < BLOCKIF_NUMTHR; i++)
pthread_join(bc->bc_btid[i], &jval);
/* XXX Cancel queued i/o's ??? */
/*
* Release resources
*/
bc->bc_magic = 0;
close(bc->bc_fd);
free(bc);
return (0);
} }
/* int
* Return virtual C/H/S values for a given block. Use the algorithm blockbe_write(block_backend_t *be, struct blockif_req *breq)
* outlined in the VHD specification to calculate values.
*/
void
blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h, uint8_t *s)
{ {
off_t sectors; /* total sectors of the block dev */ assert(be != NULL);
off_t hcyl; /* cylinders times heads */ return (be->write(be, breq));
uint16_t secpt; /* sectors per track */
uint8_t heads;
assert(bc->bc_magic == BLOCKIF_SIG);
sectors = bc->bc_size / bc->bc_sectsz;
/* Clamp the size to the largest possible with CHS */
if (sectors > 65535UL*16*255)
sectors = 65535UL*16*255;
if (sectors >= 65536UL*16*63) {
secpt = 255;
heads = 16;
hcyl = sectors / secpt;
} else {
secpt = 17;
hcyl = sectors / secpt;
heads = (hcyl + 1023) / 1024;
if (heads < 4)
heads = 4;
if (hcyl >= (heads * 1024) || heads > 16) {
secpt = 31;
heads = 16;
hcyl = sectors / secpt;
} }
if (hcyl >= (heads * 1024)) {
secpt = 63;
heads = 16;
hcyl = sectors / secpt;
}
}
*c = hcyl / heads;
*h = heads;
*s = secpt;
}
/*
* Accessors
*/
off_t
blockif_size(struct blockif_ctxt *bc)
{
assert(bc->bc_magic == BLOCKIF_SIG);
return (bc->bc_size);
}
int int
blockif_sectsz(struct blockif_ctxt *bc) blockbe_flush(block_backend_t *be, struct blockif_req *breq)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->flush(be, breq));
return (bc->bc_sectsz);
} }
void
blockif_psectsz(struct blockif_ctxt *bc, int *size, int *off)
{
assert(bc->bc_magic == BLOCKIF_SIG);
*size = bc->bc_psectsz;
*off = bc->bc_psectoff;
}
int int
blockif_queuesz(struct blockif_ctxt *bc) blockbe_delete(block_backend_t *be, struct blockif_req *breq)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->delete(be, breq));
return (BLOCKIF_MAXREQ - 1);
} }
int int
blockif_is_ro(struct blockif_ctxt *bc) blockbe_cancel(block_backend_t *be, struct blockif_req *breq)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->cancel(be, breq));
return (bc->bc_rdonly);
} }
int int
blockif_candelete(struct blockif_ctxt *bc) blockbe_close(block_backend_t *be)
{ {
assert(be != NULL);
assert(bc->bc_magic == BLOCKIF_SIG); return (be->close(be));
return (bc->bc_candelete);
} }