freebsd-dev/module/zfs/zvol.c
Brian Behlendorf f74a147c02 Fix NULL deref when zvol_alloc() fails
If zvol_alloc() fails zv will be set to NULL and dereferenced
in out_dmu_objset_disown.  To avoid this entirely the zv->objset
line is moved up in to the success block.

Original-patch-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1109
2012-11-27 14:10:31 -08:00

1504 lines
36 KiB
C

/*
* 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 http://www.opensolaris.org/os/licensing.
* 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) 2008-2010 Lawrence Livermore National Security, LLC.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Rewritten for Linux by Brian Behlendorf <behlendorf1@llnl.gov>.
* LLNL-CODE-403049.
*
* ZFS volume emulation driver.
*
* Makes a DMU object look like a volume of arbitrary size, up to 2^64 bytes.
* Volumes are accessed through the symbolic links named:
*
* /dev/<pool_name>/<dataset_name>
*
* Volumes are persistent through reboot and module load. No user command
* needs to be run before opening and using a device.
*/
#include <sys/dmu_traverse.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_prop.h>
#include <sys/zap.h>
#include <sys/zil_impl.h>
#include <sys/zio.h>
#include <sys/zfs_rlock.h>
#include <sys/zfs_znode.h>
#include <sys/zvol.h>
#include <linux/blkdev_compat.h>
unsigned int zvol_inhibit_dev = 0;
unsigned int zvol_major = ZVOL_MAJOR;
unsigned int zvol_threads = 32;
unsigned long zvol_max_discard_blocks = 16384;
static taskq_t *zvol_taskq;
static kmutex_t zvol_state_lock;
static list_t zvol_state_list;
static char *zvol_tag = "zvol_tag";
/*
* The in-core state of each volume.
*/
typedef struct zvol_state {
char zv_name[MAXNAMELEN]; /* name */
uint64_t zv_volsize; /* advertised space */
uint64_t zv_volblocksize;/* volume block size */
objset_t *zv_objset; /* objset handle */
uint32_t zv_flags; /* ZVOL_* flags */
uint32_t zv_open_count; /* open counts */
uint32_t zv_changed; /* disk changed */
zilog_t *zv_zilog; /* ZIL handle */
znode_t zv_znode; /* for range locking */
dmu_buf_t *zv_dbuf; /* bonus handle */
dev_t zv_dev; /* device id */
struct gendisk *zv_disk; /* generic disk */
struct request_queue *zv_queue; /* request queue */
spinlock_t zv_lock; /* request queue lock */
list_node_t zv_next; /* next zvol_state_t linkage */
} zvol_state_t;
#define ZVOL_RDONLY 0x1
/*
* Find the next available range of ZVOL_MINORS minor numbers. The
* zvol_state_list is kept in ascending minor order so we simply need
* to scan the list for the first gap in the sequence. This allows us
* to recycle minor number as devices are created and removed.
*/
static int
zvol_find_minor(unsigned *minor)
{
zvol_state_t *zv;
*minor = 0;
ASSERT(MUTEX_HELD(&zvol_state_lock));
for (zv = list_head(&zvol_state_list); zv != NULL;
zv = list_next(&zvol_state_list, zv), *minor += ZVOL_MINORS) {
if (MINOR(zv->zv_dev) != MINOR(*minor))
break;
}
/* All minors are in use */
if (*minor >= (1 << MINORBITS))
return ENXIO;
return 0;
}
/*
* Find a zvol_state_t given the full major+minor dev_t.
*/
static zvol_state_t *
zvol_find_by_dev(dev_t dev)
{
zvol_state_t *zv;
ASSERT(MUTEX_HELD(&zvol_state_lock));
for (zv = list_head(&zvol_state_list); zv != NULL;
zv = list_next(&zvol_state_list, zv)) {
if (zv->zv_dev == dev)
return zv;
}
return NULL;
}
/*
* Find a zvol_state_t given the name provided at zvol_alloc() time.
*/
static zvol_state_t *
zvol_find_by_name(const char *name)
{
zvol_state_t *zv;
ASSERT(MUTEX_HELD(&zvol_state_lock));
for (zv = list_head(&zvol_state_list); zv != NULL;
zv = list_next(&zvol_state_list, zv)) {
if (!strncmp(zv->zv_name, name, MAXNAMELEN))
return zv;
}
return NULL;
}
/*
* ZFS_IOC_CREATE callback handles dmu zvol and zap object creation.
*/
void
zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
{
zfs_creat_t *zct = arg;
nvlist_t *nvprops = zct->zct_props;
int error;
uint64_t volblocksize, volsize;
VERIFY(nvlist_lookup_uint64(nvprops,
zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
if (nvlist_lookup_uint64(nvprops,
zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);
/*
* These properties must be removed from the list so the generic
* property setting step won't apply to them.
*/
VERIFY(nvlist_remove_all(nvprops,
zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
(void) nvlist_remove_all(nvprops,
zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE));
error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize,
DMU_OT_NONE, 0, tx);
ASSERT(error == 0);
error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP,
DMU_OT_NONE, 0, tx);
ASSERT(error == 0);
error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx);
ASSERT(error == 0);
}
/*
* ZFS_IOC_OBJSET_STATS entry point.
*/
int
zvol_get_stats(objset_t *os, nvlist_t *nv)
{
int error;
dmu_object_info_t *doi;
uint64_t val;
error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val);
if (error)
return (error);
dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);
doi = kmem_alloc(sizeof(dmu_object_info_t), KM_SLEEP);
error = dmu_object_info(os, ZVOL_OBJ, doi);
if (error == 0) {
dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE,
doi->doi_data_block_size);
}
kmem_free(doi, sizeof(dmu_object_info_t));
return (error);
}
/*
* Sanity check volume size.
*/
int
zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
{
if (volsize == 0)
return (EINVAL);
if (volsize % blocksize != 0)
return (EINVAL);
#ifdef _ILP32
if (volsize - 1 > MAXOFFSET_T)
return (EOVERFLOW);
#endif
return (0);
}
/*
* Ensure the zap is flushed then inform the VFS of the capacity change.
*/
static int
zvol_update_volsize(zvol_state_t *zv, uint64_t volsize, objset_t *os)
{
struct block_device *bdev;
dmu_tx_t *tx;
int error;
ASSERT(MUTEX_HELD(&zvol_state_lock));
tx = dmu_tx_create(os);
dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
return (error);
}
error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
&volsize, tx);
dmu_tx_commit(tx);
if (error)
return (error);
error = dmu_free_long_range(os,
ZVOL_OBJ, volsize, DMU_OBJECT_END);
if (error)
return (error);
bdev = bdget_disk(zv->zv_disk, 0);
if (!bdev)
return (EIO);
/*
* 2.6.28 API change
* Added check_disk_size_change() helper function.
*/
#ifdef HAVE_CHECK_DISK_SIZE_CHANGE
set_capacity(zv->zv_disk, volsize >> 9);
zv->zv_volsize = volsize;
check_disk_size_change(zv->zv_disk, bdev);
#else
zv->zv_volsize = volsize;
zv->zv_changed = 1;
(void) check_disk_change(bdev);
#endif /* HAVE_CHECK_DISK_SIZE_CHANGE */
bdput(bdev);
return (0);
}
/*
* Set ZFS_PROP_VOLSIZE set entry point.
*/
int
zvol_set_volsize(const char *name, uint64_t volsize)
{
zvol_state_t *zv;
dmu_object_info_t *doi;
objset_t *os = NULL;
uint64_t readonly;
int error;
mutex_enter(&zvol_state_lock);
zv = zvol_find_by_name(name);
if (zv == NULL) {
error = ENXIO;
goto out;
}
doi = kmem_alloc(sizeof(dmu_object_info_t), KM_SLEEP);
error = dmu_objset_hold(name, FTAG, &os);
if (error)
goto out_doi;
if ((error = dmu_object_info(os, ZVOL_OBJ, doi)) != 0 ||
(error = zvol_check_volsize(volsize,doi->doi_data_block_size)) != 0)
goto out_doi;
VERIFY(dsl_prop_get_integer(name, "readonly", &readonly, NULL) == 0);
if (readonly) {
error = EROFS;
goto out_doi;
}
if (get_disk_ro(zv->zv_disk) || (zv->zv_flags & ZVOL_RDONLY)) {
error = EROFS;
goto out_doi;
}
error = zvol_update_volsize(zv, volsize, os);
out_doi:
kmem_free(doi, sizeof(dmu_object_info_t));
out:
if (os)
dmu_objset_rele(os, FTAG);
mutex_exit(&zvol_state_lock);
return (error);
}
/*
* Sanity check volume block size.
*/
int
zvol_check_volblocksize(uint64_t volblocksize)
{
if (volblocksize < SPA_MINBLOCKSIZE ||
volblocksize > SPA_MAXBLOCKSIZE ||
!ISP2(volblocksize))
return (EDOM);
return (0);
}
/*
* Set ZFS_PROP_VOLBLOCKSIZE set entry point.
*/
int
zvol_set_volblocksize(const char *name, uint64_t volblocksize)
{
zvol_state_t *zv;
dmu_tx_t *tx;
int error;
mutex_enter(&zvol_state_lock);
zv = zvol_find_by_name(name);
if (zv == NULL) {
error = ENXIO;
goto out;
}
if (get_disk_ro(zv->zv_disk) || (zv->zv_flags & ZVOL_RDONLY)) {
error = EROFS;
goto out;
}
tx = dmu_tx_create(zv->zv_objset);
dmu_tx_hold_bonus(tx, ZVOL_OBJ);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
} else {
error = dmu_object_set_blocksize(zv->zv_objset, ZVOL_OBJ,
volblocksize, 0, tx);
if (error == ENOTSUP)
error = EBUSY;
dmu_tx_commit(tx);
if (error == 0)
zv->zv_volblocksize = volblocksize;
}
out:
mutex_exit(&zvol_state_lock);
return (error);
}
/*
* Replay a TX_WRITE ZIL transaction that didn't get committed
* after a system failure
*/
static int
zvol_replay_write(zvol_state_t *zv, lr_write_t *lr, boolean_t byteswap)
{
objset_t *os = zv->zv_objset;
char *data = (char *)(lr + 1); /* data follows lr_write_t */
uint64_t off = lr->lr_offset;
uint64_t len = lr->lr_length;
dmu_tx_t *tx;
int error;
if (byteswap)
byteswap_uint64_array(lr, sizeof (*lr));
tx = dmu_tx_create(os);
dmu_tx_hold_write(tx, ZVOL_OBJ, off, len);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
} else {
dmu_write(os, ZVOL_OBJ, off, len, data, tx);
dmu_tx_commit(tx);
}
return (error);
}
static int
zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
{
return (ENOTSUP);
}
/*
* Callback vectors for replaying records.
* Only TX_WRITE is needed for zvol.
*/
zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = {
(zil_replay_func_t *)zvol_replay_err, /* no such transaction type */
(zil_replay_func_t *)zvol_replay_err, /* TX_CREATE */
(zil_replay_func_t *)zvol_replay_err, /* TX_MKDIR */
(zil_replay_func_t *)zvol_replay_err, /* TX_MKXATTR */
(zil_replay_func_t *)zvol_replay_err, /* TX_SYMLINK */
(zil_replay_func_t *)zvol_replay_err, /* TX_REMOVE */
(zil_replay_func_t *)zvol_replay_err, /* TX_RMDIR */
(zil_replay_func_t *)zvol_replay_err, /* TX_LINK */
(zil_replay_func_t *)zvol_replay_err, /* TX_RENAME */
(zil_replay_func_t *)zvol_replay_write, /* TX_WRITE */
(zil_replay_func_t *)zvol_replay_err, /* TX_TRUNCATE */
(zil_replay_func_t *)zvol_replay_err, /* TX_SETATTR */
(zil_replay_func_t *)zvol_replay_err, /* TX_ACL */
};
/*
* zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
*
* We store data in the log buffers if it's small enough.
* Otherwise we will later flush the data out via dmu_sync().
*/
ssize_t zvol_immediate_write_sz = 32768;
static void
zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx,
uint64_t offset, uint64_t size, int sync)
{
uint32_t blocksize = zv->zv_volblocksize;
zilog_t *zilog = zv->zv_zilog;
boolean_t slogging;
ssize_t immediate_write_sz;
if (zil_replaying(zilog, tx))
return;
immediate_write_sz = (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
? 0 : zvol_immediate_write_sz;
slogging = spa_has_slogs(zilog->zl_spa) &&
(zilog->zl_logbias == ZFS_LOGBIAS_LATENCY);
while (size) {
itx_t *itx;
lr_write_t *lr;
ssize_t len;
itx_wr_state_t write_state;
/*
* Unlike zfs_log_write() we can be called with
* up to DMU_MAX_ACCESS/2 (5MB) writes.
*/
if (blocksize > immediate_write_sz && !slogging &&
size >= blocksize && offset % blocksize == 0) {
write_state = WR_INDIRECT; /* uses dmu_sync */
len = blocksize;
} else if (sync) {
write_state = WR_COPIED;
len = MIN(ZIL_MAX_LOG_DATA, size);
} else {
write_state = WR_NEED_COPY;
len = MIN(ZIL_MAX_LOG_DATA, size);
}
itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
(write_state == WR_COPIED ? len : 0));
lr = (lr_write_t *)&itx->itx_lr;
if (write_state == WR_COPIED && dmu_read(zv->zv_objset,
ZVOL_OBJ, offset, len, lr+1, DMU_READ_NO_PREFETCH) != 0) {
zil_itx_destroy(itx);
itx = zil_itx_create(TX_WRITE, sizeof (*lr));
lr = (lr_write_t *)&itx->itx_lr;
write_state = WR_NEED_COPY;
}
itx->itx_wr_state = write_state;
if (write_state == WR_NEED_COPY)
itx->itx_sod += len;
lr->lr_foid = ZVOL_OBJ;
lr->lr_offset = offset;
lr->lr_length = len;
lr->lr_blkoff = 0;
BP_ZERO(&lr->lr_blkptr);
itx->itx_private = zv;
itx->itx_sync = sync;
(void) zil_itx_assign(zilog, itx, tx);
offset += len;
size -= len;
}
}
/*
* Common write path running under the zvol taskq context. This function
* is responsible for copying the request structure data in to the DMU and
* signaling the request queue with the result of the copy.
*/
static void
zvol_write(void *arg)
{
struct request *req = (struct request *)arg;
struct request_queue *q = req->q;
zvol_state_t *zv = q->queuedata;
uint64_t offset = blk_rq_pos(req) << 9;
uint64_t size = blk_rq_bytes(req);
int error = 0;
dmu_tx_t *tx;
rl_t *rl;
/*
* Annotate this call path with a flag that indicates that it is
* unsafe to use KM_SLEEP during memory allocations due to the
* potential for a deadlock. KM_PUSHPAGE should be used instead.
*/
ASSERT(!(current->flags & PF_NOFS));
current->flags |= PF_NOFS;
if (req->cmd_flags & VDEV_REQ_FLUSH)
zil_commit(zv->zv_zilog, ZVOL_OBJ);
/*
* Some requests are just for flush and nothing else.
*/
if (size == 0) {
blk_end_request(req, 0, size);
goto out;
}
rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_WRITER);
tx = dmu_tx_create(zv->zv_objset);
dmu_tx_hold_write(tx, ZVOL_OBJ, offset, size);
/* This will only fail for ENOSPC */
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
zfs_range_unlock(rl);
blk_end_request(req, -error, size);
goto out;
}
error = dmu_write_req(zv->zv_objset, ZVOL_OBJ, req, tx);
if (error == 0)
zvol_log_write(zv, tx, offset, size,
req->cmd_flags & VDEV_REQ_FUA);
dmu_tx_commit(tx);
zfs_range_unlock(rl);
if ((req->cmd_flags & VDEV_REQ_FUA) ||
zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS)
zil_commit(zv->zv_zilog, ZVOL_OBJ);
blk_end_request(req, -error, size);
out:
current->flags &= ~PF_NOFS;
}
#ifdef HAVE_BLK_QUEUE_DISCARD
static void
zvol_discard(void *arg)
{
struct request *req = (struct request *)arg;
struct request_queue *q = req->q;
zvol_state_t *zv = q->queuedata;
uint64_t start = blk_rq_pos(req) << 9;
uint64_t end = start + blk_rq_bytes(req);
int error;
rl_t *rl;
/*
* Annotate this call path with a flag that indicates that it is
* unsafe to use KM_SLEEP during memory allocations due to the
* potential for a deadlock. KM_PUSHPAGE should be used instead.
*/
ASSERT(!(current->flags & PF_NOFS));
current->flags |= PF_NOFS;
if (end > zv->zv_volsize) {
blk_end_request(req, -EIO, blk_rq_bytes(req));
goto out;
}
/*
* Align the request to volume block boundaries. If we don't,
* then this will force dnode_free_range() to zero out the
* unaligned parts, which is slow (read-modify-write) and
* useless since we are not freeing any space by doing so.
*/
start = P2ROUNDUP(start, zv->zv_volblocksize);
end = P2ALIGN(end, zv->zv_volblocksize);
if (start >= end) {
blk_end_request(req, 0, blk_rq_bytes(req));
goto out;
}
rl = zfs_range_lock(&zv->zv_znode, start, end - start, RL_WRITER);
error = dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, start, end - start);
/*
* TODO: maybe we should add the operation to the log.
*/
zfs_range_unlock(rl);
blk_end_request(req, -error, blk_rq_bytes(req));
out:
current->flags &= ~PF_NOFS;
}
#endif /* HAVE_BLK_QUEUE_DISCARD */
/*
* Common read path running under the zvol taskq context. This function
* is responsible for copying the requested data out of the DMU and in to
* a linux request structure. It then must signal the request queue with
* an error code describing the result of the copy.
*/
static void
zvol_read(void *arg)
{
struct request *req = (struct request *)arg;
struct request_queue *q = req->q;
zvol_state_t *zv = q->queuedata;
uint64_t offset = blk_rq_pos(req) << 9;
uint64_t size = blk_rq_bytes(req);
int error;
rl_t *rl;
if (size == 0) {
blk_end_request(req, 0, size);
return;
}
rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_READER);
error = dmu_read_req(zv->zv_objset, ZVOL_OBJ, req);
zfs_range_unlock(rl);
/* convert checksum errors into IO errors */
if (error == ECKSUM)
error = EIO;
blk_end_request(req, -error, size);
}
/*
* Request will be added back to the request queue and retried if
* it cannot be immediately dispatched to the taskq for handling
*/
static inline void
zvol_dispatch(task_func_t func, struct request *req)
{
if (!taskq_dispatch(zvol_taskq, func, (void *)req, TQ_NOSLEEP))
blk_requeue_request(req->q, req);
}
/*
* Common request path. Rather than registering a custom make_request()
* function we use the generic Linux version. This is done because it allows
* us to easily merge read requests which would otherwise we performed
* synchronously by the DMU. This is less critical in write case where the
* DMU will perform the correct merging within a transaction group. Using
* the generic make_request() also let's use leverage the fact that the
* elevator with ensure correct ordering in regards to barrior IOs. On
* the downside it means that in the write case we end up doing request
* merging twice once in the elevator and once in the DMU.
*
* The request handler is called under a spin lock so all the real work
* is handed off to be done in the context of the zvol taskq. This function
* simply performs basic request sanity checking and hands off the request.
*/
static void
zvol_request(struct request_queue *q)
{
zvol_state_t *zv = q->queuedata;
struct request *req;
unsigned int size;
while ((req = blk_fetch_request(q)) != NULL) {
size = blk_rq_bytes(req);
if (size != 0 && blk_rq_pos(req) + blk_rq_sectors(req) >
get_capacity(zv->zv_disk)) {
printk(KERN_INFO
"%s: bad access: block=%llu, count=%lu\n",
req->rq_disk->disk_name,
(long long unsigned)blk_rq_pos(req),
(long unsigned)blk_rq_sectors(req));
__blk_end_request(req, -EIO, size);
continue;
}
if (!blk_fs_request(req)) {
printk(KERN_INFO "%s: non-fs cmd\n",
req->rq_disk->disk_name);
__blk_end_request(req, -EIO, size);
continue;
}
switch (rq_data_dir(req)) {
case READ:
zvol_dispatch(zvol_read, req);
break;
case WRITE:
if (unlikely(get_disk_ro(zv->zv_disk)) ||
unlikely(zv->zv_flags & ZVOL_RDONLY)) {
__blk_end_request(req, -EROFS, size);
break;
}
#ifdef HAVE_BLK_QUEUE_DISCARD
if (req->cmd_flags & VDEV_REQ_DISCARD) {
zvol_dispatch(zvol_discard, req);
break;
}
#endif /* HAVE_BLK_QUEUE_DISCARD */
zvol_dispatch(zvol_write, req);
break;
default:
printk(KERN_INFO "%s: unknown cmd: %d\n",
req->rq_disk->disk_name, (int)rq_data_dir(req));
__blk_end_request(req, -EIO, size);
break;
}
}
}
static void
zvol_get_done(zgd_t *zgd, int error)
{
if (zgd->zgd_db)
dmu_buf_rele(zgd->zgd_db, zgd);
zfs_range_unlock(zgd->zgd_rl);
if (error == 0 && zgd->zgd_bp)
zil_add_block(zgd->zgd_zilog, zgd->zgd_bp);
kmem_free(zgd, sizeof (zgd_t));
}
/*
* Get data to generate a TX_WRITE intent log record.
*/
static int
zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
{
zvol_state_t *zv = arg;
objset_t *os = zv->zv_objset;
uint64_t offset = lr->lr_offset;
uint64_t size = lr->lr_length;
dmu_buf_t *db;
zgd_t *zgd;
int error;
ASSERT(zio != NULL);
ASSERT(size != 0);
zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_PUSHPAGE);
zgd->zgd_zilog = zv->zv_zilog;
zgd->zgd_rl = zfs_range_lock(&zv->zv_znode, offset, size, RL_READER);
/*
* Write records come in two flavors: immediate and indirect.
* For small writes it's cheaper to store the data with the
* log record (immediate); for large writes it's cheaper to
* sync the data and get a pointer to it (indirect) so that
* we don't have to write the data twice.
*/
if (buf != NULL) { /* immediate write */
error = dmu_read(os, ZVOL_OBJ, offset, size, buf,
DMU_READ_NO_PREFETCH);
} else {
size = zv->zv_volblocksize;
offset = P2ALIGN_TYPED(offset, size, uint64_t);
error = dmu_buf_hold(os, ZVOL_OBJ, offset, zgd, &db,
DMU_READ_NO_PREFETCH);
if (error == 0) {
zgd->zgd_db = db;
zgd->zgd_bp = &lr->lr_blkptr;
ASSERT(db != NULL);
ASSERT(db->db_offset == offset);
ASSERT(db->db_size == size);
error = dmu_sync(zio, lr->lr_common.lrc_txg,
zvol_get_done, zgd);
if (error == 0)
return (0);
}
}
zvol_get_done(zgd, error);
return (error);
}
/*
* The zvol_state_t's are inserted in increasing MINOR(dev_t) order.
*/
static void
zvol_insert(zvol_state_t *zv_insert)
{
zvol_state_t *zv = NULL;
ASSERT(MUTEX_HELD(&zvol_state_lock));
ASSERT3U(MINOR(zv_insert->zv_dev) & ZVOL_MINOR_MASK, ==, 0);
for (zv = list_head(&zvol_state_list); zv != NULL;
zv = list_next(&zvol_state_list, zv)) {
if (MINOR(zv->zv_dev) > MINOR(zv_insert->zv_dev))
break;
}
list_insert_before(&zvol_state_list, zv, zv_insert);
}
/*
* Simply remove the zvol from to list of zvols.
*/
static void
zvol_remove(zvol_state_t *zv_remove)
{
ASSERT(MUTEX_HELD(&zvol_state_lock));
list_remove(&zvol_state_list, zv_remove);
}
static int
zvol_first_open(zvol_state_t *zv)
{
objset_t *os;
uint64_t volsize;
int error;
uint64_t ro;
/* lie and say we're read-only */
error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, zvol_tag, &os);
if (error)
return (-error);
error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
if (error) {
dmu_objset_disown(os, zvol_tag);
return (-error);
}
zv->zv_objset = os;
error = dmu_bonus_hold(os, ZVOL_OBJ, zvol_tag, &zv->zv_dbuf);
if (error) {
dmu_objset_disown(os, zvol_tag);
return (-error);
}
set_capacity(zv->zv_disk, volsize >> 9);
zv->zv_volsize = volsize;
zv->zv_zilog = zil_open(os, zvol_get_data);
VERIFY(dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL) == 0);
if (ro || dmu_objset_is_snapshot(os)) {
set_disk_ro(zv->zv_disk, 1);
zv->zv_flags |= ZVOL_RDONLY;
} else {
set_disk_ro(zv->zv_disk, 0);
zv->zv_flags &= ~ZVOL_RDONLY;
}
return (-error);
}
static void
zvol_last_close(zvol_state_t *zv)
{
zil_close(zv->zv_zilog);
zv->zv_zilog = NULL;
dmu_buf_rele(zv->zv_dbuf, zvol_tag);
zv->zv_dbuf = NULL;
/*
* Evict cached data
*/
if (dsl_dataset_is_dirty(dmu_objset_ds(zv->zv_objset)) &&
!(zv->zv_flags & ZVOL_RDONLY))
txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
(void) dmu_objset_evict_dbufs(zv->zv_objset);
dmu_objset_disown(zv->zv_objset, zvol_tag);
zv->zv_objset = NULL;
}
static int
zvol_open(struct block_device *bdev, fmode_t flag)
{
zvol_state_t *zv = bdev->bd_disk->private_data;
int error = 0, drop_mutex = 0;
/*
* If the caller is already holding the mutex do not take it
* again, this will happen as part of zvol_create_minor().
* Once add_disk() is called the device is live and the kernel
* will attempt to open it to read the partition information.
*/
if (!mutex_owned(&zvol_state_lock)) {
mutex_enter(&zvol_state_lock);
drop_mutex = 1;
}
ASSERT3P(zv, !=, NULL);
if (zv->zv_open_count == 0) {
error = zvol_first_open(zv);
if (error)
goto out_mutex;
}
if ((flag & FMODE_WRITE) &&
(get_disk_ro(zv->zv_disk) || (zv->zv_flags & ZVOL_RDONLY))) {
error = -EROFS;
goto out_open_count;
}
zv->zv_open_count++;
out_open_count:
if (zv->zv_open_count == 0)
zvol_last_close(zv);
out_mutex:
if (drop_mutex)
mutex_exit(&zvol_state_lock);
check_disk_change(bdev);
return (error);
}
static int
zvol_release(struct gendisk *disk, fmode_t mode)
{
zvol_state_t *zv = disk->private_data;
int drop_mutex = 0;
if (!mutex_owned(&zvol_state_lock)) {
mutex_enter(&zvol_state_lock);
drop_mutex = 1;
}
ASSERT3P(zv, !=, NULL);
ASSERT3U(zv->zv_open_count, >, 0);
zv->zv_open_count--;
if (zv->zv_open_count == 0)
zvol_last_close(zv);
if (drop_mutex)
mutex_exit(&zvol_state_lock);
return (0);
}
static int
zvol_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
zvol_state_t *zv = bdev->bd_disk->private_data;
int error = 0;
if (zv == NULL)
return (-ENXIO);
switch (cmd) {
case BLKFLSBUF:
zil_commit(zv->zv_zilog, ZVOL_OBJ);
break;
case BLKZNAME:
error = copy_to_user((void *)arg, zv->zv_name, MAXNAMELEN);
break;
default:
error = -ENOTTY;
break;
}
return (error);
}
#ifdef CONFIG_COMPAT
static int
zvol_compat_ioctl(struct block_device *bdev, fmode_t mode,
unsigned cmd, unsigned long arg)
{
return zvol_ioctl(bdev, mode, cmd, arg);
}
#else
#define zvol_compat_ioctl NULL
#endif
static int zvol_media_changed(struct gendisk *disk)
{
zvol_state_t *zv = disk->private_data;
return zv->zv_changed;
}
static int zvol_revalidate_disk(struct gendisk *disk)
{
zvol_state_t *zv = disk->private_data;
zv->zv_changed = 0;
set_capacity(zv->zv_disk, zv->zv_volsize >> 9);
return 0;
}
/*
* Provide a simple virtual geometry for legacy compatibility. For devices
* smaller than 1 MiB a small head and sector count is used to allow very
* tiny devices. For devices over 1 Mib a standard head and sector count
* is used to keep the cylinders count reasonable.
*/
static int
zvol_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
zvol_state_t *zv = bdev->bd_disk->private_data;
sector_t sectors = get_capacity(zv->zv_disk);
if (sectors > 2048) {
geo->heads = 16;
geo->sectors = 63;
} else {
geo->heads = 2;
geo->sectors = 4;
}
geo->start = 0;
geo->cylinders = sectors / (geo->heads * geo->sectors);
return 0;
}
static struct kobject *
zvol_probe(dev_t dev, int *part, void *arg)
{
zvol_state_t *zv;
struct kobject *kobj;
mutex_enter(&zvol_state_lock);
zv = zvol_find_by_dev(dev);
kobj = zv ? get_disk(zv->zv_disk) : NULL;
mutex_exit(&zvol_state_lock);
return kobj;
}
#ifdef HAVE_BDEV_BLOCK_DEVICE_OPERATIONS
static struct block_device_operations zvol_ops = {
.open = zvol_open,
.release = zvol_release,
.ioctl = zvol_ioctl,
.compat_ioctl = zvol_compat_ioctl,
.media_changed = zvol_media_changed,
.revalidate_disk = zvol_revalidate_disk,
.getgeo = zvol_getgeo,
.owner = THIS_MODULE,
};
#else /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
static int
zvol_open_by_inode(struct inode *inode, struct file *file)
{
return zvol_open(inode->i_bdev, file->f_mode);
}
static int
zvol_release_by_inode(struct inode *inode, struct file *file)
{
return zvol_release(inode->i_bdev->bd_disk, file->f_mode);
}
static int
zvol_ioctl_by_inode(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
if (file == NULL || inode == NULL)
return -EINVAL;
return zvol_ioctl(inode->i_bdev, file->f_mode, cmd, arg);
}
# ifdef CONFIG_COMPAT
static long
zvol_compat_ioctl_by_inode(struct file *file,
unsigned int cmd, unsigned long arg)
{
if (file == NULL)
return -EINVAL;
return zvol_compat_ioctl(file->f_dentry->d_inode->i_bdev,
file->f_mode, cmd, arg);
}
# else
# define zvol_compat_ioctl_by_inode NULL
# endif
static struct block_device_operations zvol_ops = {
.open = zvol_open_by_inode,
.release = zvol_release_by_inode,
.ioctl = zvol_ioctl_by_inode,
.compat_ioctl = zvol_compat_ioctl_by_inode,
.media_changed = zvol_media_changed,
.revalidate_disk = zvol_revalidate_disk,
.getgeo = zvol_getgeo,
.owner = THIS_MODULE,
};
#endif /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
/*
* Allocate memory for a new zvol_state_t and setup the required
* request queue and generic disk structures for the block device.
*/
static zvol_state_t *
zvol_alloc(dev_t dev, const char *name)
{
zvol_state_t *zv;
int error = 0;
zv = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
if (zv == NULL)
goto out;
zv->zv_queue = blk_init_queue(zvol_request, &zv->zv_lock);
if (zv->zv_queue == NULL)
goto out_kmem;
#ifdef HAVE_ELEVATOR_CHANGE
error = elevator_change(zv->zv_queue, "noop");
#endif /* HAVE_ELEVATOR_CHANGE */
if (error) {
printk("ZFS: Unable to set \"%s\" scheduler for zvol %s: %d\n",
"noop", name, error);
goto out_queue;
}
#ifdef HAVE_BLK_QUEUE_FLUSH
blk_queue_flush(zv->zv_queue, VDEV_REQ_FLUSH | VDEV_REQ_FUA);
#else
blk_queue_ordered(zv->zv_queue, QUEUE_ORDERED_DRAIN, NULL);
#endif /* HAVE_BLK_QUEUE_FLUSH */
zv->zv_disk = alloc_disk(ZVOL_MINORS);
if (zv->zv_disk == NULL)
goto out_queue;
zv->zv_queue->queuedata = zv;
zv->zv_dev = dev;
zv->zv_open_count = 0;
strlcpy(zv->zv_name, name, MAXNAMELEN);
mutex_init(&zv->zv_znode.z_range_lock, NULL, MUTEX_DEFAULT, NULL);
avl_create(&zv->zv_znode.z_range_avl, zfs_range_compare,
sizeof (rl_t), offsetof(rl_t, r_node));
zv->zv_znode.z_is_zvol = TRUE;
spin_lock_init(&zv->zv_lock);
list_link_init(&zv->zv_next);
zv->zv_disk->major = zvol_major;
zv->zv_disk->first_minor = (dev & MINORMASK);
zv->zv_disk->fops = &zvol_ops;
zv->zv_disk->private_data = zv;
zv->zv_disk->queue = zv->zv_queue;
snprintf(zv->zv_disk->disk_name, DISK_NAME_LEN, "%s%d",
ZVOL_DEV_NAME, (dev & MINORMASK));
return zv;
out_queue:
blk_cleanup_queue(zv->zv_queue);
out_kmem:
kmem_free(zv, sizeof (zvol_state_t));
out:
return NULL;
}
/*
* Cleanup then free a zvol_state_t which was created by zvol_alloc().
*/
static void
zvol_free(zvol_state_t *zv)
{
avl_destroy(&zv->zv_znode.z_range_avl);
mutex_destroy(&zv->zv_znode.z_range_lock);
del_gendisk(zv->zv_disk);
blk_cleanup_queue(zv->zv_queue);
put_disk(zv->zv_disk);
kmem_free(zv, sizeof (zvol_state_t));
}
static int
__zvol_create_minor(const char *name)
{
zvol_state_t *zv;
objset_t *os;
dmu_object_info_t *doi;
uint64_t volsize;
unsigned minor = 0;
int error = 0;
ASSERT(MUTEX_HELD(&zvol_state_lock));
zv = zvol_find_by_name(name);
if (zv) {
error = EEXIST;
goto out;
}
doi = kmem_alloc(sizeof(dmu_object_info_t), KM_SLEEP);
error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, zvol_tag, &os);
if (error)
goto out_doi;
error = dmu_object_info(os, ZVOL_OBJ, doi);
if (error)
goto out_dmu_objset_disown;
error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
if (error)
goto out_dmu_objset_disown;
error = zvol_find_minor(&minor);
if (error)
goto out_dmu_objset_disown;
zv = zvol_alloc(MKDEV(zvol_major, minor), name);
if (zv == NULL) {
error = EAGAIN;
goto out_dmu_objset_disown;
}
if (dmu_objset_is_snapshot(os))
zv->zv_flags |= ZVOL_RDONLY;
zv->zv_volblocksize = doi->doi_data_block_size;
zv->zv_volsize = volsize;
zv->zv_objset = os;
set_capacity(zv->zv_disk, zv->zv_volsize >> 9);
blk_queue_max_hw_sectors(zv->zv_queue, UINT_MAX);
blk_queue_max_segments(zv->zv_queue, UINT16_MAX);
blk_queue_max_segment_size(zv->zv_queue, UINT_MAX);
blk_queue_physical_block_size(zv->zv_queue, zv->zv_volblocksize);
blk_queue_io_opt(zv->zv_queue, zv->zv_volblocksize);
#ifdef HAVE_BLK_QUEUE_DISCARD
blk_queue_max_discard_sectors(zv->zv_queue,
(zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
blk_queue_discard_granularity(zv->zv_queue, zv->zv_volblocksize);
queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zv->zv_queue);
#endif
#ifdef HAVE_BLK_QUEUE_NONROT
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zv->zv_queue);
#endif
if (zil_replay_disable)
zil_destroy(dmu_objset_zil(os), B_FALSE);
else
zil_replay(os, zv, zvol_replay_vector);
zv->zv_objset = NULL;
out_dmu_objset_disown:
dmu_objset_disown(os, zvol_tag);
out_doi:
kmem_free(doi, sizeof(dmu_object_info_t));
out:
if (error == 0) {
zvol_insert(zv);
add_disk(zv->zv_disk);
}
return (error);
}
/*
* Create a block device minor node and setup the linkage between it
* and the specified volume. Once this function returns the block
* device is live and ready for use.
*/
int
zvol_create_minor(const char *name)
{
int error;
mutex_enter(&zvol_state_lock);
error = __zvol_create_minor(name);
mutex_exit(&zvol_state_lock);
return (error);
}
static int
__zvol_remove_minor(const char *name)
{
zvol_state_t *zv;
ASSERT(MUTEX_HELD(&zvol_state_lock));
zv = zvol_find_by_name(name);
if (zv == NULL)
return (ENXIO);
if (zv->zv_open_count > 0)
return (EBUSY);
zvol_remove(zv);
zvol_free(zv);
return (0);
}
/*
* Remove a block device minor node for the specified volume.
*/
int
zvol_remove_minor(const char *name)
{
int error;
mutex_enter(&zvol_state_lock);
error = __zvol_remove_minor(name);
mutex_exit(&zvol_state_lock);
return (error);
}
static int
zvol_create_minors_cb(spa_t *spa, uint64_t dsobj,
const char *dsname, void *arg)
{
if (strchr(dsname, '/') == NULL)
return 0;
(void) __zvol_create_minor(dsname);
return (0);
}
/*
* Create minors for specified pool, if pool is NULL create minors
* for all available pools.
*/
int
zvol_create_minors(const char *pool)
{
spa_t *spa = NULL;
int error = 0;
if (zvol_inhibit_dev)
return (0);
mutex_enter(&zvol_state_lock);
if (pool) {
error = dmu_objset_find_spa(NULL, pool, zvol_create_minors_cb,
NULL, DS_FIND_CHILDREN | DS_FIND_SNAPSHOTS);
} else {
mutex_enter(&spa_namespace_lock);
while ((spa = spa_next(spa)) != NULL) {
error = dmu_objset_find_spa(NULL,
spa_name(spa), zvol_create_minors_cb, NULL,
DS_FIND_CHILDREN | DS_FIND_SNAPSHOTS);
if (error)
break;
}
mutex_exit(&spa_namespace_lock);
}
mutex_exit(&zvol_state_lock);
return error;
}
/*
* Remove minors for specified pool, if pool is NULL remove all minors.
*/
void
zvol_remove_minors(const char *pool)
{
zvol_state_t *zv, *zv_next;
char *str;
if (zvol_inhibit_dev)
return;
str = kmem_zalloc(MAXNAMELEN, KM_SLEEP);
if (pool) {
(void) strncpy(str, pool, strlen(pool));
(void) strcat(str, "/");
}
mutex_enter(&zvol_state_lock);
for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
zv_next = list_next(&zvol_state_list, zv);
if (pool == NULL || !strncmp(str, zv->zv_name, strlen(str))) {
zvol_remove(zv);
zvol_free(zv);
}
}
mutex_exit(&zvol_state_lock);
kmem_free(str, MAXNAMELEN);
}
int
zvol_init(void)
{
int error;
zvol_taskq = taskq_create(ZVOL_DRIVER, zvol_threads, maxclsyspri,
zvol_threads, INT_MAX, TASKQ_PREPOPULATE);
if (zvol_taskq == NULL) {
printk(KERN_INFO "ZFS: taskq_create() failed\n");
return (-ENOMEM);
}
error = register_blkdev(zvol_major, ZVOL_DRIVER);
if (error) {
printk(KERN_INFO "ZFS: register_blkdev() failed %d\n", error);
taskq_destroy(zvol_taskq);
return (error);
}
blk_register_region(MKDEV(zvol_major, 0), 1UL << MINORBITS,
THIS_MODULE, zvol_probe, NULL, NULL);
mutex_init(&zvol_state_lock, NULL, MUTEX_DEFAULT, NULL);
list_create(&zvol_state_list, sizeof (zvol_state_t),
offsetof(zvol_state_t, zv_next));
(void) zvol_create_minors(NULL);
return (0);
}
void
zvol_fini(void)
{
zvol_remove_minors(NULL);
blk_unregister_region(MKDEV(zvol_major, 0), 1UL << MINORBITS);
unregister_blkdev(zvol_major, ZVOL_DRIVER);
taskq_destroy(zvol_taskq);
mutex_destroy(&zvol_state_lock);
list_destroy(&zvol_state_list);
}
module_param(zvol_inhibit_dev, uint, 0644);
MODULE_PARM_DESC(zvol_inhibit_dev, "Do not create zvol device nodes");
module_param(zvol_major, uint, 0444);
MODULE_PARM_DESC(zvol_major, "Major number for zvol device");
module_param(zvol_threads, uint, 0444);
MODULE_PARM_DESC(zvol_threads, "Number of threads for zvol device");
module_param(zvol_max_discard_blocks, ulong, 0444);
MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard at once");