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mirror_zfs/module/zfs/zvol.c
Matthew Macy b43893de86 Rename rangelock_ functions to zfs_rangelock_ 
A rangelock KPI already exists on FreeBSD.  Add a zfs_ prefix as
per our convention to prevent any conflict with existing symbols.

Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9402
2020-01-22 13:49:02 -08:00

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/*
* 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.
*
* Copyright 2014 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2016 Actifio, Inc. All rights reserved.
* Copyright (c) 2012, 2019 by Delphix. All rights reserved.
*/
/*
* Note on locking of zvol state structures.
*
* These structures are used to maintain internal state used to emulate block
* devices on top of zvols. In particular, management of device minor number
* operations - create, remove, rename, and set_snapdev - involves access to
* these structures. The zvol_state_lock is primarily used to protect the
* zvol_state_list. The zv->zv_state_lock is used to protect the contents
* of the zvol_state_t structures, as well as to make sure that when the
* time comes to remove the structure from the list, it is not in use, and
* therefore, it can be taken off zvol_state_list and freed.
*
* The zv_suspend_lock was introduced to allow for suspending I/O to a zvol,
* e.g. for the duration of receive and rollback operations. This lock can be
* held for significant periods of time. Given that it is undesirable to hold
* mutexes for long periods of time, the following lock ordering applies:
* - take zvol_state_lock if necessary, to protect zvol_state_list
* - take zv_suspend_lock if necessary, by the code path in question
* - take zv_state_lock to protect zvol_state_t
*
* The minor operations are issued to spa->spa_zvol_taskq queues, that are
* single-threaded (to preserve order of minor operations), and are executed
* through the zvol_task_cb that dispatches the specific operations. Therefore,
* these operations are serialized per pool. Consequently, we can be certain
* that for a given zvol, there is only one operation at a time in progress.
* That is why one can be sure that first, zvol_state_t for a given zvol is
* allocated and placed on zvol_state_list, and then other minor operations
* for this zvol are going to proceed in the order of issue.
*
* It is also worth keeping in mind that once add_disk() is called, the zvol is
* announced to the world, and zvol_open()/zvol_release() can be called at any
* time. Incidentally, add_disk() itself calls zvol_open()->zvol_first_open()
* and zvol_release()->zvol_last_close() directly as well.
*/
#include <sys/dataset_kstats.h>
#include <sys/dbuf.h>
#include <sys/dmu_traverse.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_prop.h>
#include <sys/dsl_dir.h>
#include <sys/zap.h>
#include <sys/zfeature.h>
#include <sys/zil_impl.h>
#include <sys/dmu_tx.h>
#include <sys/zio.h>
#include <sys/zfs_rlock.h>
#include <sys/spa_impl.h>
#include <sys/zvol.h>
#include <linux/blkdev_compat.h>
#include <linux/task_io_accounting_ops.h>
unsigned int zvol_inhibit_dev = 0;
unsigned int zvol_major = ZVOL_MAJOR;
unsigned int zvol_threads = 32;
unsigned int zvol_request_sync = 0;
unsigned int zvol_prefetch_bytes = (128 * 1024);
unsigned long zvol_max_discard_blocks = 16384;
unsigned int zvol_volmode = ZFS_VOLMODE_GEOM;
static taskq_t *zvol_taskq;
static krwlock_t zvol_state_lock;
static list_t zvol_state_list;
#define ZVOL_HT_SIZE 1024
static struct hlist_head *zvol_htable;
#define ZVOL_HT_HEAD(hash) (&zvol_htable[(hash) & (ZVOL_HT_SIZE-1)])
static struct ida zvol_ida;
/*
* The in-core state of each volume.
*/
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 */
rangelock_t zv_rangelock; /* for range locking */
dnode_t *zv_dn; /* dnode hold */
dev_t zv_dev; /* device id */
struct gendisk *zv_disk; /* generic disk */
struct request_queue *zv_queue; /* request queue */
dataset_kstats_t zv_kstat; /* zvol kstats */
list_node_t zv_next; /* next zvol_state_t linkage */
uint64_t zv_hash; /* name hash */
struct hlist_node zv_hlink; /* hash link */
kmutex_t zv_state_lock; /* protects zvol_state_t */
atomic_t zv_suspend_ref; /* refcount for suspend */
krwlock_t zv_suspend_lock; /* suspend lock */
};
typedef enum {
ZVOL_ASYNC_CREATE_MINORS,
ZVOL_ASYNC_REMOVE_MINORS,
ZVOL_ASYNC_RENAME_MINORS,
ZVOL_ASYNC_SET_SNAPDEV,
ZVOL_ASYNC_SET_VOLMODE,
ZVOL_ASYNC_MAX
} zvol_async_op_t;
typedef struct {
zvol_async_op_t op;
char pool[MAXNAMELEN];
char name1[MAXNAMELEN];
char name2[MAXNAMELEN];
zprop_source_t source;
uint64_t value;
} zvol_task_t;
#define ZVOL_RDONLY 0x1
/*
* Whether the zvol has been written to (as opposed to ZVOL_RDONLY, which
* specifies whether or not the zvol _can_ be written to)
*/
#define ZVOL_WRITTEN_TO 0x2
static uint64_t
zvol_name_hash(const char *name)
{
int i;
uint64_t crc = -1ULL;
uint8_t *p = (uint8_t *)name;
ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
for (i = 0; i < MAXNAMELEN - 1 && *p; i++, p++) {
crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (*p)) & 0xFF];
}
return (crc);
}
/*
* Find a zvol_state_t given the full major+minor dev_t. If found,
* return with zv_state_lock taken, otherwise, return (NULL) without
* taking zv_state_lock.
*/
static zvol_state_t *
zvol_find_by_dev(dev_t dev)
{
zvol_state_t *zv;
rw_enter(&zvol_state_lock, RW_READER);
for (zv = list_head(&zvol_state_list); zv != NULL;
zv = list_next(&zvol_state_list, zv)) {
mutex_enter(&zv->zv_state_lock);
if (zv->zv_dev == dev) {
rw_exit(&zvol_state_lock);
return (zv);
}
mutex_exit(&zv->zv_state_lock);
}
rw_exit(&zvol_state_lock);
return (NULL);
}
/*
* Find a zvol_state_t given the name and hash generated by zvol_name_hash.
* If found, return with zv_suspend_lock and zv_state_lock taken, otherwise,
* return (NULL) without the taking locks. The zv_suspend_lock is always taken
* before zv_state_lock. The mode argument indicates the mode (including none)
* for zv_suspend_lock to be taken.
*/
static zvol_state_t *
zvol_find_by_name_hash(const char *name, uint64_t hash, int mode)
{
zvol_state_t *zv;
struct hlist_node *p = NULL;
rw_enter(&zvol_state_lock, RW_READER);
hlist_for_each(p, ZVOL_HT_HEAD(hash)) {
zv = hlist_entry(p, zvol_state_t, zv_hlink);
mutex_enter(&zv->zv_state_lock);
if (zv->zv_hash == hash &&
strncmp(zv->zv_name, name, MAXNAMELEN) == 0) {
/*
* this is the right zvol, take the locks in the
* right order
*/
if (mode != RW_NONE &&
!rw_tryenter(&zv->zv_suspend_lock, mode)) {
mutex_exit(&zv->zv_state_lock);
rw_enter(&zv->zv_suspend_lock, mode);
mutex_enter(&zv->zv_state_lock);
/*
* zvol cannot be renamed as we continue
* to hold zvol_state_lock
*/
ASSERT(zv->zv_hash == hash &&
strncmp(zv->zv_name, name, MAXNAMELEN)
== 0);
}
rw_exit(&zvol_state_lock);
return (zv);
}
mutex_exit(&zv->zv_state_lock);
}
rw_exit(&zvol_state_lock);
return (NULL);
}
/*
* Find a zvol_state_t given the name.
* If found, return with zv_suspend_lock and zv_state_lock taken, otherwise,
* return (NULL) without the taking locks. The zv_suspend_lock is always taken
* before zv_state_lock. The mode argument indicates the mode (including none)
* for zv_suspend_lock to be taken.
*/
static zvol_state_t *
zvol_find_by_name(const char *name, int mode)
{
return (zvol_find_by_name_hash(name, zvol_name_hash(name), mode));
}
/*
* Given a path, return TRUE if path is a ZVOL.
*/
boolean_t
zvol_is_zvol(const char *device)
{
struct block_device *bdev;
unsigned int major;
bdev = vdev_lookup_bdev(device);
if (IS_ERR(bdev))
return (B_FALSE);
major = MAJOR(bdev->bd_dev);
bdput(bdev);
if (major == zvol_major)
return (B_TRUE);
return (B_FALSE);
}
/*
* 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 (SET_ERROR(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 (SET_ERROR(error));
}
/*
* Sanity check volume size.
*/
int
zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
{
if (volsize == 0)
return (SET_ERROR(EINVAL));
if (volsize % blocksize != 0)
return (SET_ERROR(EINVAL));
#ifdef _ILP32
if (volsize - 1 > SPEC_MAXOFFSET_T)
return (SET_ERROR(EOVERFLOW));
#endif
return (0);
}
/*
* Ensure the zap is flushed then inform the VFS of the capacity change.
*/
static int
zvol_update_volsize(uint64_t volsize, objset_t *os)
{
dmu_tx_t *tx;
int error;
uint64_t txg;
tx = dmu_tx_create(os);
dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
dmu_tx_mark_netfree(tx);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
return (SET_ERROR(error));
}
txg = dmu_tx_get_txg(tx);
error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
&volsize, tx);
dmu_tx_commit(tx);
txg_wait_synced(dmu_objset_pool(os), txg);
if (error == 0)
error = dmu_free_long_range(os,
ZVOL_OBJ, volsize, DMU_OBJECT_END);
return (error);
}
/*
* Set ZFS_PROP_VOLSIZE set entry point. Note that modifying the volume
* size will result in a udev "change" event being generated.
*/
int
zvol_set_volsize(const char *name, uint64_t volsize)
{
objset_t *os = NULL;
struct gendisk *disk = NULL;
uint64_t readonly;
int error;
boolean_t owned = B_FALSE;
error = dsl_prop_get_integer(name,
zfs_prop_to_name(ZFS_PROP_READONLY), &readonly, NULL);
if (error != 0)
return (SET_ERROR(error));
if (readonly)
return (SET_ERROR(EROFS));
zvol_state_t *zv = zvol_find_by_name(name, RW_READER);
ASSERT(zv == NULL || (MUTEX_HELD(&zv->zv_state_lock) &&
RW_READ_HELD(&zv->zv_suspend_lock)));
if (zv == NULL || zv->zv_objset == NULL) {
if (zv != NULL)
rw_exit(&zv->zv_suspend_lock);
if ((error = dmu_objset_own(name, DMU_OST_ZVOL, B_FALSE, B_TRUE,
FTAG, &os)) != 0) {
if (zv != NULL)
mutex_exit(&zv->zv_state_lock);
return (SET_ERROR(error));
}
owned = B_TRUE;
if (zv != NULL)
zv->zv_objset = os;
} else {
os = zv->zv_objset;
}
dmu_object_info_t *doi = kmem_alloc(sizeof (*doi), KM_SLEEP);
if ((error = dmu_object_info(os, ZVOL_OBJ, doi)) ||
(error = zvol_check_volsize(volsize, doi->doi_data_block_size)))
goto out;
error = zvol_update_volsize(volsize, os);
if (error == 0 && zv != NULL) {
zv->zv_volsize = volsize;
zv->zv_changed = 1;
disk = zv->zv_disk;
}
out:
kmem_free(doi, sizeof (dmu_object_info_t));
if (owned) {
dmu_objset_disown(os, B_TRUE, FTAG);
if (zv != NULL)
zv->zv_objset = NULL;
} else {
rw_exit(&zv->zv_suspend_lock);
}
if (zv != NULL)
mutex_exit(&zv->zv_state_lock);
if (disk != NULL)
revalidate_disk(disk);
return (SET_ERROR(error));
}
/*
* Sanity check volume block size.
*/
int
zvol_check_volblocksize(const char *name, uint64_t volblocksize)
{
/* Record sizes above 128k need the feature to be enabled */
if (volblocksize > SPA_OLD_MAXBLOCKSIZE) {
spa_t *spa;
int error;
if ((error = spa_open(name, &spa, FTAG)) != 0)
return (error);
if (!spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS)) {
spa_close(spa, FTAG);
return (SET_ERROR(ENOTSUP));
}
/*
* We don't allow setting the property above 1MB,
* unless the tunable has been changed.
*/
if (volblocksize > zfs_max_recordsize)
return (SET_ERROR(EDOM));
spa_close(spa, FTAG);
}
if (volblocksize < SPA_MINBLOCKSIZE ||
volblocksize > SPA_MAXBLOCKSIZE ||
!ISP2(volblocksize))
return (SET_ERROR(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;
zv = zvol_find_by_name(name, RW_READER);
if (zv == NULL)
return (SET_ERROR(ENXIO));
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
if (zv->zv_flags & ZVOL_RDONLY) {
mutex_exit(&zv->zv_state_lock);
rw_exit(&zv->zv_suspend_lock);
return (SET_ERROR(EROFS));
}
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 = SET_ERROR(EBUSY);
dmu_tx_commit(tx);
if (error == 0)
zv->zv_volblocksize = volblocksize;
}
mutex_exit(&zv->zv_state_lock);
rw_exit(&zv->zv_suspend_lock);
return (SET_ERROR(error));
}
/*
* Replay a TX_TRUNCATE ZIL transaction if asked. TX_TRUNCATE is how we
* implement DKIOCFREE/free-long-range.
*/
static int
zvol_replay_truncate(void *arg1, void *arg2, boolean_t byteswap)
{
zvol_state_t *zv = arg1;
lr_truncate_t *lr = arg2;
uint64_t offset, length;
if (byteswap)
byteswap_uint64_array(lr, sizeof (*lr));
offset = lr->lr_offset;
length = lr->lr_length;
return (dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, offset, length));
}
/*
* Replay a TX_WRITE ZIL transaction that didn't get committed
* after a system failure
*/
static int
zvol_replay_write(void *arg1, void *arg2, boolean_t byteswap)
{
zvol_state_t *zv = arg1;
lr_write_t *lr = arg2;
objset_t *os = zv->zv_objset;
char *data = (char *)(lr + 1); /* data follows lr_write_t */
uint64_t offset, length;
dmu_tx_t *tx;
int error;
if (byteswap)
byteswap_uint64_array(lr, sizeof (*lr));
offset = lr->lr_offset;
length = lr->lr_length;
/* If it's a dmu_sync() block, write the whole block */
if (lr->lr_common.lrc_reclen == sizeof (lr_write_t)) {
uint64_t blocksize = BP_GET_LSIZE(&lr->lr_blkptr);
if (length < blocksize) {
offset -= offset % blocksize;
length = blocksize;
}
}
tx = dmu_tx_create(os);
dmu_tx_hold_write(tx, ZVOL_OBJ, offset, length);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
} else {
dmu_write(os, ZVOL_OBJ, offset, length, data, tx);
dmu_tx_commit(tx);
}
return (error);
}
static int
zvol_replay_err(void *arg1, void *arg2, boolean_t byteswap)
{
return (SET_ERROR(ENOTSUP));
}
/*
* Callback vectors for replaying records.
* Only TX_WRITE and TX_TRUNCATE are needed for zvol.
*/
zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = {
zvol_replay_err, /* no such transaction type */
zvol_replay_err, /* TX_CREATE */
zvol_replay_err, /* TX_MKDIR */
zvol_replay_err, /* TX_MKXATTR */
zvol_replay_err, /* TX_SYMLINK */
zvol_replay_err, /* TX_REMOVE */
zvol_replay_err, /* TX_RMDIR */
zvol_replay_err, /* TX_LINK */
zvol_replay_err, /* TX_RENAME */
zvol_replay_write, /* TX_WRITE */
zvol_replay_truncate, /* TX_TRUNCATE */
zvol_replay_err, /* TX_SETATTR */
zvol_replay_err, /* TX_ACL */
zvol_replay_err, /* TX_CREATE_ATTR */
zvol_replay_err, /* TX_CREATE_ACL_ATTR */
zvol_replay_err, /* TX_MKDIR_ACL */
zvol_replay_err, /* TX_MKDIR_ATTR */
zvol_replay_err, /* TX_MKDIR_ACL_ATTR */
zvol_replay_err, /* TX_WRITE2 */
};
/*
* 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;
itx_wr_state_t write_state;
if (zil_replaying(zilog, tx))
return;
if (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
write_state = WR_INDIRECT;
else if (!spa_has_slogs(zilog->zl_spa) &&
size >= blocksize && blocksize > zvol_immediate_write_sz)
write_state = WR_INDIRECT;
else if (sync)
write_state = WR_COPIED;
else
write_state = WR_NEED_COPY;
while (size) {
itx_t *itx;
lr_write_t *lr;
itx_wr_state_t wr_state = write_state;
ssize_t len = size;
if (wr_state == WR_COPIED && size > zil_max_copied_data(zilog))
wr_state = WR_NEED_COPY;
else if (wr_state == WR_INDIRECT)
len = MIN(blocksize - P2PHASE(offset, blocksize), size);
itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
(wr_state == WR_COPIED ? len : 0));
lr = (lr_write_t *)&itx->itx_lr;
if (wr_state == WR_COPIED && dmu_read_by_dnode(zv->zv_dn,
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;
wr_state = WR_NEED_COPY;
}
itx->itx_wr_state = wr_state;
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;
}
}
typedef struct zv_request {
zvol_state_t *zv;
struct bio *bio;
locked_range_t *lr;
} zv_request_t;
static void
uio_from_bio(uio_t *uio, struct bio *bio)
{
uio->uio_bvec = &bio->bi_io_vec[BIO_BI_IDX(bio)];
uio->uio_iovcnt = bio->bi_vcnt - BIO_BI_IDX(bio);
uio->uio_loffset = BIO_BI_SECTOR(bio) << 9;
uio->uio_segflg = UIO_BVEC;
uio->uio_limit = MAXOFFSET_T;
uio->uio_resid = BIO_BI_SIZE(bio);
uio->uio_skip = BIO_BI_SKIP(bio);
}
static void
zvol_write(void *arg)
{
int error = 0;
zv_request_t *zvr = arg;
struct bio *bio = zvr->bio;
uio_t uio = { { 0 }, 0 };
uio_from_bio(&uio, bio);
zvol_state_t *zv = zvr->zv;
ASSERT(zv && zv->zv_open_count > 0);
ASSERT(zv->zv_zilog != NULL);
ssize_t start_resid = uio.uio_resid;
unsigned long start_jif = jiffies;
blk_generic_start_io_acct(zv->zv_queue, WRITE, bio_sectors(bio),
&zv->zv_disk->part0);
boolean_t sync =
bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
uint64_t volsize = zv->zv_volsize;
while (uio.uio_resid > 0 && uio.uio_loffset < volsize) {
uint64_t bytes = MIN(uio.uio_resid, DMU_MAX_ACCESS >> 1);
uint64_t off = uio.uio_loffset;
dmu_tx_t *tx = dmu_tx_create(zv->zv_objset);
if (bytes > volsize - off) /* don't write past the end */
bytes = volsize - off;
dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
/* This will only fail for ENOSPC */
error = dmu_tx_assign(tx, TXG_WAIT);
if (error) {
dmu_tx_abort(tx);
break;
}
error = dmu_write_uio_dnode(zv->zv_dn, &uio, bytes, tx);
if (error == 0) {
zvol_log_write(zv, tx, off, bytes, sync);
}
dmu_tx_commit(tx);
if (error)
break;
}
zfs_rangelock_exit(zvr->lr);
int64_t nwritten = start_resid - uio.uio_resid;
dataset_kstats_update_write_kstats(&zv->zv_kstat, nwritten);
task_io_account_write(nwritten);
if (sync)
zil_commit(zv->zv_zilog, ZVOL_OBJ);
rw_exit(&zv->zv_suspend_lock);
blk_generic_end_io_acct(zv->zv_queue, WRITE, &zv->zv_disk->part0,
start_jif);
BIO_END_IO(bio, -error);
kmem_free(zvr, sizeof (zv_request_t));
}
/*
* Log a DKIOCFREE/free-long-range to the ZIL with TX_TRUNCATE.
*/
static void
zvol_log_truncate(zvol_state_t *zv, dmu_tx_t *tx, uint64_t off, uint64_t len,
boolean_t sync)
{
itx_t *itx;
lr_truncate_t *lr;
zilog_t *zilog = zv->zv_zilog;
if (zil_replaying(zilog, tx))
return;
itx = zil_itx_create(TX_TRUNCATE, sizeof (*lr));
lr = (lr_truncate_t *)&itx->itx_lr;
lr->lr_foid = ZVOL_OBJ;
lr->lr_offset = off;
lr->lr_length = len;
itx->itx_sync = sync;
zil_itx_assign(zilog, itx, tx);
}
static void
zvol_discard(void *arg)
{
zv_request_t *zvr = arg;
struct bio *bio = zvr->bio;
zvol_state_t *zv = zvr->zv;
uint64_t start = BIO_BI_SECTOR(bio) << 9;
uint64_t size = BIO_BI_SIZE(bio);
uint64_t end = start + size;
boolean_t sync;
int error = 0;
dmu_tx_t *tx;
unsigned long start_jif;
ASSERT(zv && zv->zv_open_count > 0);
ASSERT(zv->zv_zilog != NULL);
start_jif = jiffies;
blk_generic_start_io_acct(zv->zv_queue, WRITE, bio_sectors(bio),
&zv->zv_disk->part0);
sync = bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
if (end > zv->zv_volsize) {
error = SET_ERROR(EIO);
goto unlock;
}
/*
* Align the request to volume block boundaries when a secure erase is
* not required. This will prevent dnode_free_range() from zeroing out
* the unaligned parts which is slow (read-modify-write) and useless
* since we are not freeing any space by doing so.
*/
if (!bio_is_secure_erase(bio)) {
start = P2ROUNDUP(start, zv->zv_volblocksize);
end = P2ALIGN(end, zv->zv_volblocksize);
size = end - start;
}
if (start >= end)
goto unlock;
tx = dmu_tx_create(zv->zv_objset);
dmu_tx_mark_netfree(tx);
error = dmu_tx_assign(tx, TXG_WAIT);
if (error != 0) {
dmu_tx_abort(tx);
} else {
zvol_log_truncate(zv, tx, start, size, B_TRUE);
dmu_tx_commit(tx);
error = dmu_free_long_range(zv->zv_objset,
ZVOL_OBJ, start, size);
}
unlock:
zfs_rangelock_exit(zvr->lr);
if (error == 0 && sync)
zil_commit(zv->zv_zilog, ZVOL_OBJ);
rw_exit(&zv->zv_suspend_lock);
blk_generic_end_io_acct(zv->zv_queue, WRITE, &zv->zv_disk->part0,
start_jif);
BIO_END_IO(bio, -error);
kmem_free(zvr, sizeof (zv_request_t));
}
static void
zvol_read(void *arg)
{
int error = 0;
zv_request_t *zvr = arg;
struct bio *bio = zvr->bio;
uio_t uio = { { 0 }, 0 };
uio_from_bio(&uio, bio);
zvol_state_t *zv = zvr->zv;
ASSERT(zv && zv->zv_open_count > 0);
ssize_t start_resid = uio.uio_resid;
unsigned long start_jif = jiffies;
blk_generic_start_io_acct(zv->zv_queue, READ, bio_sectors(bio),
&zv->zv_disk->part0);
uint64_t volsize = zv->zv_volsize;
while (uio.uio_resid > 0 && uio.uio_loffset < volsize) {
uint64_t bytes = MIN(uio.uio_resid, DMU_MAX_ACCESS >> 1);
/* don't read past the end */
if (bytes > volsize - uio.uio_loffset)
bytes = volsize - uio.uio_loffset;
error = dmu_read_uio_dnode(zv->zv_dn, &uio, bytes);
if (error) {
/* convert checksum errors into IO errors */
if (error == ECKSUM)
error = SET_ERROR(EIO);
break;
}
}
zfs_rangelock_exit(zvr->lr);
int64_t nread = start_resid - uio.uio_resid;
dataset_kstats_update_read_kstats(&zv->zv_kstat, nread);
task_io_account_read(nread);
rw_exit(&zv->zv_suspend_lock);
blk_generic_end_io_acct(zv->zv_queue, READ, &zv->zv_disk->part0,
start_jif);
BIO_END_IO(bio, -error);
kmem_free(zvr, sizeof (zv_request_t));
}
/* ARGSUSED */
static void
zvol_get_done(zgd_t *zgd, int error)
{
if (zgd->zgd_db)
dmu_buf_rele(zgd->zgd_db, zgd);
zfs_rangelock_exit(zgd->zgd_lr);
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, struct lwb *lwb, zio_t *zio)
{
zvol_state_t *zv = arg;
uint64_t offset = lr->lr_offset;
uint64_t size = lr->lr_length;
dmu_buf_t *db;
zgd_t *zgd;
int error;
ASSERT3P(lwb, !=, NULL);
ASSERT3P(zio, !=, NULL);
ASSERT3U(size, !=, 0);
zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
zgd->zgd_lwb = lwb;
/*
* 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 */
zgd->zgd_lr = zfs_rangelock_enter(&zv->zv_rangelock, offset,
size, RL_READER);
error = dmu_read_by_dnode(zv->zv_dn, offset, size, buf,
DMU_READ_NO_PREFETCH);
} else { /* indirect write */
/*
* Have to lock the whole block to ensure when it's written out
* and its checksum is being calculated that no one can change
* the data. Contrarily to zfs_get_data we need not re-check
* blocksize after we get the lock because it cannot be changed.
*/
size = zv->zv_volblocksize;
offset = P2ALIGN_TYPED(offset, size, uint64_t);
zgd->zgd_lr = zfs_rangelock_enter(&zv->zv_rangelock, offset,
size, RL_READER);
error = dmu_buf_hold_by_dnode(zv->zv_dn, offset, zgd, &db,
DMU_READ_NO_PREFETCH);
if (error == 0) {
blkptr_t *bp = &lr->lr_blkptr;
zgd->zgd_db = db;
zgd->zgd_bp = bp;
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 (SET_ERROR(error));
}
static MAKE_REQUEST_FN_RET
zvol_request(struct request_queue *q, struct bio *bio)
{
zvol_state_t *zv = q->queuedata;
fstrans_cookie_t cookie = spl_fstrans_mark();
uint64_t offset = BIO_BI_SECTOR(bio) << 9;
uint64_t size = BIO_BI_SIZE(bio);
int rw = bio_data_dir(bio);
zv_request_t *zvr;
if (bio_has_data(bio) && offset + size > zv->zv_volsize) {
printk(KERN_INFO
"%s: bad access: offset=%llu, size=%lu\n",
zv->zv_disk->disk_name,
(long long unsigned)offset,
(long unsigned)size);
BIO_END_IO(bio, -SET_ERROR(EIO));
goto out;
}
if (rw == WRITE) {
boolean_t need_sync = B_FALSE;
if (unlikely(zv->zv_flags & ZVOL_RDONLY)) {
BIO_END_IO(bio, -SET_ERROR(EROFS));
goto out;
}
/*
* To be released in the I/O function. See the comment on
* rangelock_enter() below.
*/
rw_enter(&zv->zv_suspend_lock, RW_READER);
/*
* Open a ZIL if this is the first time we have written to this
* zvol. We protect zv->zv_zilog with zv_suspend_lock rather
* than zv_state_lock so that we don't need to acquire an
* additional lock in this path.
*/
if (zv->zv_zilog == NULL) {
rw_exit(&zv->zv_suspend_lock);
rw_enter(&zv->zv_suspend_lock, RW_WRITER);
if (zv->zv_zilog == NULL) {
zv->zv_zilog = zil_open(zv->zv_objset,
zvol_get_data);
zv->zv_flags |= ZVOL_WRITTEN_TO;
}
rw_downgrade(&zv->zv_suspend_lock);
}
/* bio marked as FLUSH need to flush before write */
if (bio_is_flush(bio))
zil_commit(zv->zv_zilog, ZVOL_OBJ);
/* Some requests are just for flush and nothing else. */
if (size == 0) {
rw_exit(&zv->zv_suspend_lock);
BIO_END_IO(bio, 0);
goto out;
}
zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
zvr->zv = zv;
zvr->bio = bio;
/*
* To be released in the I/O function. Since the I/O functions
* are asynchronous, we take it here synchronously to make
* sure overlapped I/Os are properly ordered.
*/
zvr->lr = zfs_rangelock_enter(&zv->zv_rangelock, offset, size,
RL_WRITER);
/*
* Sync writes and discards execute zil_commit() which may need
* to take a RL_READER lock on the whole block being modified
* via its zillog->zl_get_data(): to avoid circular dependency
* issues with taskq threads execute these requests
* synchronously here in zvol_request().
*/
need_sync = bio_is_fua(bio) ||
zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
if (bio_is_discard(bio) || bio_is_secure_erase(bio)) {
if (zvol_request_sync || need_sync ||
taskq_dispatch(zvol_taskq, zvol_discard, zvr,
TQ_SLEEP) == TASKQID_INVALID)
zvol_discard(zvr);
} else {
if (zvol_request_sync || need_sync ||
taskq_dispatch(zvol_taskq, zvol_write, zvr,
TQ_SLEEP) == TASKQID_INVALID)
zvol_write(zvr);
}
} else {
/*
* The SCST driver, and possibly others, may issue READ I/Os
* with a length of zero bytes. These empty I/Os contain no
* data and require no additional handling.
*/
if (size == 0) {
BIO_END_IO(bio, 0);
goto out;
}
zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
zvr->zv = zv;
zvr->bio = bio;
rw_enter(&zv->zv_suspend_lock, RW_READER);
zvr->lr = zfs_rangelock_enter(&zv->zv_rangelock, offset, size,
RL_READER);
if (zvol_request_sync || taskq_dispatch(zvol_taskq,
zvol_read, zvr, TQ_SLEEP) == TASKQID_INVALID)
zvol_read(zvr);
}
out:
spl_fstrans_unmark(cookie);
#ifdef HAVE_MAKE_REQUEST_FN_RET_INT
return (0);
#elif defined(HAVE_MAKE_REQUEST_FN_RET_QC)
return (BLK_QC_T_NONE);
#endif
}
/*
* The zvol_state_t's are inserted into zvol_state_list and zvol_htable.
*/
static void
zvol_insert(zvol_state_t *zv)
{
ASSERT(RW_WRITE_HELD(&zvol_state_lock));
ASSERT3U(MINOR(zv->zv_dev) & ZVOL_MINOR_MASK, ==, 0);
list_insert_head(&zvol_state_list, zv);
hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));
}
/*
* Simply remove the zvol from to list of zvols.
*/
static void
zvol_remove(zvol_state_t *zv)
{
ASSERT(RW_WRITE_HELD(&zvol_state_lock));
list_remove(&zvol_state_list, zv);
hlist_del(&zv->zv_hlink);
}
/*
* Setup zv after we just own the zv->objset
*/
static int
zvol_setup_zv(zvol_state_t *zv)
{
uint64_t volsize;
int error;
uint64_t ro;
objset_t *os = zv->zv_objset;
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
ASSERT(RW_LOCK_HELD(&zv->zv_suspend_lock));
zv->zv_zilog = NULL;
zv->zv_flags &= ~ZVOL_WRITTEN_TO;
error = dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL);
if (error)
return (SET_ERROR(error));
error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
if (error)
return (SET_ERROR(error));
error = dnode_hold(os, ZVOL_OBJ, FTAG, &zv->zv_dn);
if (error)
return (SET_ERROR(error));
set_capacity(zv->zv_disk, volsize >> 9);
zv->zv_volsize = volsize;
if (ro || dmu_objset_is_snapshot(os) ||
!spa_writeable(dmu_objset_spa(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 (0);
}
/*
* Shutdown every zv_objset related stuff except zv_objset itself.
* The is the reverse of zvol_setup_zv.
*/
static void
zvol_shutdown_zv(zvol_state_t *zv)
{
ASSERT(MUTEX_HELD(&zv->zv_state_lock) &&
RW_LOCK_HELD(&zv->zv_suspend_lock));
if (zv->zv_flags & ZVOL_WRITTEN_TO) {
ASSERT(zv->zv_zilog != NULL);
zil_close(zv->zv_zilog);
}
zv->zv_zilog = NULL;
dnode_rele(zv->zv_dn, FTAG);
zv->zv_dn = NULL;
/*
* Evict cached data. We must write out any dirty data before
* disowning the dataset.
*/
if (zv->zv_flags & ZVOL_WRITTEN_TO)
txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
(void) dmu_objset_evict_dbufs(zv->zv_objset);
}
/*
* return the proper tag for rollback and recv
*/
void *
zvol_tag(zvol_state_t *zv)
{
ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
return (zv->zv_open_count > 0 ? zv : NULL);
}
/*
* Suspend the zvol for recv and rollback.
*/
zvol_state_t *
zvol_suspend(const char *name)
{
zvol_state_t *zv;
zv = zvol_find_by_name(name, RW_WRITER);
if (zv == NULL)
return (NULL);
/* block all I/O, release in zvol_resume. */
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
atomic_inc(&zv->zv_suspend_ref);
if (zv->zv_open_count > 0)
zvol_shutdown_zv(zv);
/*
* do not hold zv_state_lock across suspend/resume to
* avoid locking up zvol lookups
*/
mutex_exit(&zv->zv_state_lock);
/* zv_suspend_lock is released in zvol_resume() */
return (zv);
}
int
zvol_resume(zvol_state_t *zv)
{
int error = 0;
ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
mutex_enter(&zv->zv_state_lock);
if (zv->zv_open_count > 0) {
VERIFY0(dmu_objset_hold(zv->zv_name, zv, &zv->zv_objset));
VERIFY3P(zv->zv_objset->os_dsl_dataset->ds_owner, ==, zv);
VERIFY(dsl_dataset_long_held(zv->zv_objset->os_dsl_dataset));
dmu_objset_rele(zv->zv_objset, zv);
error = zvol_setup_zv(zv);
}
mutex_exit(&zv->zv_state_lock);
rw_exit(&zv->zv_suspend_lock);
/*
* We need this because we don't hold zvol_state_lock while releasing
* zv_suspend_lock. zvol_remove_minors_impl thus cannot check
* zv_suspend_lock to determine it is safe to free because rwlock is
* not inherent atomic.
*/
atomic_dec(&zv->zv_suspend_ref);
return (SET_ERROR(error));
}
static int
zvol_first_open(zvol_state_t *zv, boolean_t readonly)
{
objset_t *os;
int error, locked = 0;
boolean_t ro;
ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
/*
* In all other cases the spa_namespace_lock is taken before the
* bdev->bd_mutex lock. But in this case the Linux __blkdev_get()
* function calls fops->open() with the bdev->bd_mutex lock held.
* This deadlock can be easily observed with zvols used as vdevs.
*
* To avoid a potential lock inversion deadlock we preemptively
* try to take the spa_namespace_lock(). Normally it will not
* be contended and this is safe because spa_open_common() handles
* the case where the caller already holds the spa_namespace_lock.
*
* When it is contended we risk a lock inversion if we were to
* block waiting for the lock. Luckily, the __blkdev_get()
* function allows us to return -ERESTARTSYS which will result in
* bdev->bd_mutex being dropped, reacquired, and fops->open() being
* called again. This process can be repeated safely until both
* locks are acquired.
*/
if (!mutex_owned(&spa_namespace_lock)) {
locked = mutex_tryenter(&spa_namespace_lock);
if (!locked)
return (-SET_ERROR(ERESTARTSYS));
}
ro = (readonly || (strchr(zv->zv_name, '@') != NULL));
error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, ro, B_TRUE, zv, &os);
if (error)
goto out_mutex;
zv->zv_objset = os;
error = zvol_setup_zv(zv);
if (error) {
dmu_objset_disown(os, 1, zv);
zv->zv_objset = NULL;
}
out_mutex:
if (locked)
mutex_exit(&spa_namespace_lock);
return (SET_ERROR(-error));
}
static void
zvol_last_close(zvol_state_t *zv)
{
ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
zvol_shutdown_zv(zv);
dmu_objset_disown(zv->zv_objset, 1, zv);
zv->zv_objset = NULL;
}
static int
zvol_open(struct block_device *bdev, fmode_t flag)
{
zvol_state_t *zv;
int error = 0;
boolean_t drop_suspend = B_TRUE;
rw_enter(&zvol_state_lock, RW_READER);
/*
* Obtain a copy of private_data under the zvol_state_lock to make
* sure that either the result of zvol free code path setting
* bdev->bd_disk->private_data to NULL is observed, or zvol_free()
* is not called on this zv because of the positive zv_open_count.
*/
zv = bdev->bd_disk->private_data;
if (zv == NULL) {
rw_exit(&zvol_state_lock);
return (SET_ERROR(-ENXIO));
}
mutex_enter(&zv->zv_state_lock);
/*
* make sure zvol is not suspended during first open
* (hold zv_suspend_lock) and respect proper lock acquisition
* ordering - zv_suspend_lock before zv_state_lock
*/
if (zv->zv_open_count == 0) {
if (!rw_tryenter(&zv->zv_suspend_lock, RW_READER)) {
mutex_exit(&zv->zv_state_lock);
rw_enter(&zv->zv_suspend_lock, RW_READER);
mutex_enter(&zv->zv_state_lock);
/* check to see if zv_suspend_lock is needed */
if (zv->zv_open_count != 0) {
rw_exit(&zv->zv_suspend_lock);
drop_suspend = B_FALSE;
}
}
} else {
drop_suspend = B_FALSE;
}
rw_exit(&zvol_state_lock);
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
ASSERT(zv->zv_open_count != 0 || RW_READ_HELD(&zv->zv_suspend_lock));
if (zv->zv_open_count == 0) {
error = zvol_first_open(zv, !(flag & FMODE_WRITE));
if (error)
goto out_mutex;
}
if ((flag & FMODE_WRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
error = -EROFS;
goto out_open_count;
}
zv->zv_open_count++;
mutex_exit(&zv->zv_state_lock);
if (drop_suspend)
rw_exit(&zv->zv_suspend_lock);
check_disk_change(bdev);
return (0);
out_open_count:
if (zv->zv_open_count == 0)
zvol_last_close(zv);
out_mutex:
mutex_exit(&zv->zv_state_lock);
if (drop_suspend)
rw_exit(&zv->zv_suspend_lock);
if (error == -ERESTARTSYS)
schedule();
return (SET_ERROR(error));
}
#ifdef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
static void
#else
static int
#endif
zvol_release(struct gendisk *disk, fmode_t mode)
{
zvol_state_t *zv;
boolean_t drop_suspend = B_TRUE;
rw_enter(&zvol_state_lock, RW_READER);
zv = disk->private_data;
mutex_enter(&zv->zv_state_lock);
ASSERT(zv->zv_open_count > 0);
/*
* make sure zvol is not suspended during last close
* (hold zv_suspend_lock) and respect proper lock acquisition
* ordering - zv_suspend_lock before zv_state_lock
*/
if (zv->zv_open_count == 1) {
if (!rw_tryenter(&zv->zv_suspend_lock, RW_READER)) {
mutex_exit(&zv->zv_state_lock);
rw_enter(&zv->zv_suspend_lock, RW_READER);
mutex_enter(&zv->zv_state_lock);
/* check to see if zv_suspend_lock is needed */
if (zv->zv_open_count != 1) {
rw_exit(&zv->zv_suspend_lock);
drop_suspend = B_FALSE;
}
}
} else {
drop_suspend = B_FALSE;
}
rw_exit(&zvol_state_lock);
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
ASSERT(zv->zv_open_count != 1 || RW_READ_HELD(&zv->zv_suspend_lock));
zv->zv_open_count--;
if (zv->zv_open_count == 0)
zvol_last_close(zv);
mutex_exit(&zv->zv_state_lock);
if (drop_suspend)
rw_exit(&zv->zv_suspend_lock);
#ifndef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
return (0);
#endif
}
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;
ASSERT3U(zv->zv_open_count, >, 0);
switch (cmd) {
case BLKFLSBUF:
fsync_bdev(bdev);
invalidate_bdev(bdev);
rw_enter(&zv->zv_suspend_lock, RW_READER);
if (!(zv->zv_flags & ZVOL_RDONLY))
txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
rw_exit(&zv->zv_suspend_lock);
break;
case BLKZNAME:
mutex_enter(&zv->zv_state_lock);
error = copy_to_user((void *)arg, zv->zv_name, MAXNAMELEN);
mutex_exit(&zv->zv_state_lock);
break;
default:
error = -ENOTTY;
break;
}
return (SET_ERROR(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
/*
* Linux 2.6.38 preferred interface.
*/
#ifdef HAVE_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS
static unsigned int
zvol_check_events(struct gendisk *disk, unsigned int clearing)
{
unsigned int mask = 0;
rw_enter(&zvol_state_lock, RW_READER);
zvol_state_t *zv = disk->private_data;
if (zv != NULL) {
mutex_enter(&zv->zv_state_lock);
mask = zv->zv_changed ? DISK_EVENT_MEDIA_CHANGE : 0;
zv->zv_changed = 0;
mutex_exit(&zv->zv_state_lock);
}
rw_exit(&zvol_state_lock);
return (mask);
}
#else
static int zvol_media_changed(struct gendisk *disk)
{
int changed = 0;
rw_enter(&zvol_state_lock, RW_READER);
zvol_state_t *zv = disk->private_data;
if (zv != NULL) {
mutex_enter(&zv->zv_state_lock);
changed = zv->zv_changed;
zv->zv_changed = 0;
mutex_exit(&zv->zv_state_lock);
}
rw_exit(&zvol_state_lock);
return (changed);
}
#endif
static int zvol_revalidate_disk(struct gendisk *disk)
{
rw_enter(&zvol_state_lock, RW_READER);
zvol_state_t *zv = disk->private_data;
if (zv != NULL) {
mutex_enter(&zv->zv_state_lock);
set_capacity(zv->zv_disk, zv->zv_volsize >> SECTOR_BITS);
mutex_exit(&zv->zv_state_lock);
}
rw_exit(&zvol_state_lock);
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;
ASSERT3U(zv->zv_open_count, >, 0);
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;
zv = zvol_find_by_dev(dev);
kobj = zv ? get_disk_and_module(zv->zv_disk) : NULL;
ASSERT(zv == NULL || MUTEX_HELD(&zv->zv_state_lock));
if (zv)
mutex_exit(&zv->zv_state_lock);
return (kobj);
}
static struct block_device_operations zvol_ops = {
.open = zvol_open,
.release = zvol_release,
.ioctl = zvol_ioctl,
.compat_ioctl = zvol_compat_ioctl,
#ifdef HAVE_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS
.check_events = zvol_check_events,
#else
.media_changed = zvol_media_changed,
#endif
.revalidate_disk = zvol_revalidate_disk,
.getgeo = zvol_getgeo,
.owner = THIS_MODULE,
};
/*
* 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;
uint64_t volmode;
if (dsl_prop_get_integer(name, "volmode", &volmode, NULL) != 0)
return (NULL);
if (volmode == ZFS_VOLMODE_DEFAULT)
volmode = zvol_volmode;
if (volmode == ZFS_VOLMODE_NONE)
return (NULL);
zv = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
list_link_init(&zv->zv_next);
mutex_init(&zv->zv_state_lock, NULL, MUTEX_DEFAULT, NULL);
zv->zv_queue = blk_alloc_queue(GFP_ATOMIC);
if (zv->zv_queue == NULL)
goto out_kmem;
blk_queue_make_request(zv->zv_queue, zvol_request);
blk_queue_set_write_cache(zv->zv_queue, B_TRUE, B_TRUE);
/* Limit read-ahead to a single page to prevent over-prefetching. */
blk_queue_set_read_ahead(zv->zv_queue, 1);
/* Disable write merging in favor of the ZIO pipeline. */
blk_queue_flag_set(QUEUE_FLAG_NOMERGES, zv->zv_queue);
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);
zfs_rangelock_init(&zv->zv_rangelock, NULL, NULL);
rw_init(&zv->zv_suspend_lock, NULL, RW_DEFAULT, NULL);
zv->zv_disk->major = zvol_major;
#ifdef HAVE_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS
zv->zv_disk->events = DISK_EVENT_MEDIA_CHANGE;
#endif
if (volmode == ZFS_VOLMODE_DEV) {
/*
* ZFS_VOLMODE_DEV disable partitioning on ZVOL devices: set
* gendisk->minors = 1 as noted in include/linux/genhd.h.
* Also disable extended partition numbers (GENHD_FL_EXT_DEVT)
* and suppresses partition scanning (GENHD_FL_NO_PART_SCAN)
* setting gendisk->flags accordingly.
*/
zv->zv_disk->minors = 1;
#if defined(GENHD_FL_EXT_DEVT)
zv->zv_disk->flags &= ~GENHD_FL_EXT_DEVT;
#endif
#if defined(GENHD_FL_NO_PART_SCAN)
zv->zv_disk->flags |= GENHD_FL_NO_PART_SCAN;
#endif
}
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));
return (NULL);
}
/*
* Cleanup then free a zvol_state_t which was created by zvol_alloc().
* At this time, the structure is not opened by anyone, is taken off
* the zvol_state_list, and has its private data set to NULL.
* The zvol_state_lock is dropped.
*/
static void
zvol_free(void *arg)
{
zvol_state_t *zv = arg;
ASSERT(!RW_LOCK_HELD(&zv->zv_suspend_lock));
ASSERT(!MUTEX_HELD(&zv->zv_state_lock));
ASSERT(zv->zv_open_count == 0);
ASSERT(zv->zv_disk->private_data == NULL);
rw_destroy(&zv->zv_suspend_lock);
zfs_rangelock_fini(&zv->zv_rangelock);
del_gendisk(zv->zv_disk);
blk_cleanup_queue(zv->zv_queue);
put_disk(zv->zv_disk);
ida_simple_remove(&zvol_ida, MINOR(zv->zv_dev) >> ZVOL_MINOR_BITS);
mutex_destroy(&zv->zv_state_lock);
dataset_kstats_destroy(&zv->zv_kstat);
kmem_free(zv, sizeof (zvol_state_t));
}
/*
* 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.
*/
static int
zvol_create_minor_impl(const char *name)
{
zvol_state_t *zv;
objset_t *os;
dmu_object_info_t *doi;
uint64_t volsize;
uint64_t len;
unsigned minor = 0;
int error = 0;
int idx;
uint64_t hash = zvol_name_hash(name);
if (zvol_inhibit_dev)
return (0);
idx = ida_simple_get(&zvol_ida, 0, 0, kmem_flags_convert(KM_SLEEP));
if (idx < 0)
return (SET_ERROR(-idx));
minor = idx << ZVOL_MINOR_BITS;
zv = zvol_find_by_name_hash(name, hash, RW_NONE);
if (zv) {
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
mutex_exit(&zv->zv_state_lock);
ida_simple_remove(&zvol_ida, idx);
return (SET_ERROR(EEXIST));
}
doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, B_TRUE, FTAG, &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;
zv = zvol_alloc(MKDEV(zvol_major, minor), name);
if (zv == NULL) {
error = SET_ERROR(EAGAIN);
goto out_dmu_objset_disown;
}
zv->zv_hash = hash;
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, (DMU_MAX_ACCESS / 4) >> 9);
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);
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);
blk_queue_flag_set(QUEUE_FLAG_DISCARD, zv->zv_queue);
#ifdef QUEUE_FLAG_NONROT
blk_queue_flag_set(QUEUE_FLAG_NONROT, zv->zv_queue);
#endif
#ifdef QUEUE_FLAG_ADD_RANDOM
blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, zv->zv_queue);
#endif
/* This flag was introduced in kernel version 4.12. */
#ifdef QUEUE_FLAG_SCSI_PASSTHROUGH
blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, zv->zv_queue);
#endif
if (spa_writeable(dmu_objset_spa(os))) {
if (zil_replay_disable)
zil_destroy(dmu_objset_zil(os), B_FALSE);
else
zil_replay(os, zv, zvol_replay_vector);
}
ASSERT3P(zv->zv_kstat.dk_kstats, ==, NULL);
dataset_kstats_create(&zv->zv_kstat, zv->zv_objset);
/*
* When udev detects the addition of the device it will immediately
* invoke blkid(8) to determine the type of content on the device.
* Prefetching the blocks commonly scanned by blkid(8) will speed
* up this process.
*/
len = MIN(MAX(zvol_prefetch_bytes, 0), SPA_MAXBLOCKSIZE);
if (len > 0) {
dmu_prefetch(os, ZVOL_OBJ, 0, 0, len, ZIO_PRIORITY_SYNC_READ);
dmu_prefetch(os, ZVOL_OBJ, 0, volsize - len, len,
ZIO_PRIORITY_SYNC_READ);
}
zv->zv_objset = NULL;
out_dmu_objset_disown:
dmu_objset_disown(os, B_TRUE, FTAG);
out_doi:
kmem_free(doi, sizeof (dmu_object_info_t));
if (error == 0) {
rw_enter(&zvol_state_lock, RW_WRITER);
zvol_insert(zv);
rw_exit(&zvol_state_lock);
add_disk(zv->zv_disk);
} else {
ida_simple_remove(&zvol_ida, idx);
}
return (SET_ERROR(error));
}
/*
* Rename a block device minor mode for the specified volume.
*/
static void
zvol_rename_minor(zvol_state_t *zv, const char *newname)
{
int readonly = get_disk_ro(zv->zv_disk);
ASSERT(RW_LOCK_HELD(&zvol_state_lock));
ASSERT(MUTEX_HELD(&zv->zv_state_lock));
strlcpy(zv->zv_name, newname, sizeof (zv->zv_name));
/* move to new hashtable entry */
zv->zv_hash = zvol_name_hash(zv->zv_name);
hlist_del(&zv->zv_hlink);
hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));
/*
* The block device's read-only state is briefly changed causing
* a KOBJ_CHANGE uevent to be issued. This ensures udev detects
* the name change and fixes the symlinks. This does not change
* ZVOL_RDONLY in zv->zv_flags so the actual read-only state never
* changes. This would normally be done using kobject_uevent() but
* that is a GPL-only symbol which is why we need this workaround.
*/
set_disk_ro(zv->zv_disk, !readonly);
set_disk_ro(zv->zv_disk, readonly);
}
typedef struct minors_job {
list_t *list;
list_node_t link;
/* input */
char *name;
/* output */
int error;
} minors_job_t;
/*
* Prefetch zvol dnodes for the minors_job
*/
static void
zvol_prefetch_minors_impl(void *arg)
{
minors_job_t *job = arg;
char *dsname = job->name;
objset_t *os = NULL;
job->error = dmu_objset_own(dsname, DMU_OST_ZVOL, B_TRUE, B_TRUE,
FTAG, &os);
if (job->error == 0) {
dmu_prefetch(os, ZVOL_OBJ, 0, 0, 0, ZIO_PRIORITY_SYNC_READ);
dmu_objset_disown(os, B_TRUE, FTAG);
}
}
/*
* Mask errors to continue dmu_objset_find() traversal
*/
static int
zvol_create_snap_minor_cb(const char *dsname, void *arg)
{
minors_job_t *j = arg;
list_t *minors_list = j->list;
const char *name = j->name;
ASSERT0(MUTEX_HELD(&spa_namespace_lock));
/* skip the designated dataset */
if (name && strcmp(dsname, name) == 0)
return (0);
/* at this point, the dsname should name a snapshot */
if (strchr(dsname, '@') == 0) {
dprintf("zvol_create_snap_minor_cb(): "
"%s is not a snapshot name\n", dsname);
} else {
minors_job_t *job;
char *n = strdup(dsname);
if (n == NULL)
return (0);
job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP);
job->name = n;
job->list = minors_list;
job->error = 0;
list_insert_tail(minors_list, job);
/* don't care if dispatch fails, because job->error is 0 */
taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job,
TQ_SLEEP);
}
return (0);
}
/*
* Mask errors to continue dmu_objset_find() traversal
*/
static int
zvol_create_minors_cb(const char *dsname, void *arg)
{
uint64_t snapdev;
int error;
list_t *minors_list = arg;
ASSERT0(MUTEX_HELD(&spa_namespace_lock));
error = dsl_prop_get_integer(dsname, "snapdev", &snapdev, NULL);
if (error)
return (0);
/*
* Given the name and the 'snapdev' property, create device minor nodes
* with the linkages to zvols/snapshots as needed.
* If the name represents a zvol, create a minor node for the zvol, then
* check if its snapshots are 'visible', and if so, iterate over the
* snapshots and create device minor nodes for those.
*/
if (strchr(dsname, '@') == 0) {
minors_job_t *job;
char *n = strdup(dsname);
if (n == NULL)
return (0);
job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP);
job->name = n;
job->list = minors_list;
job->error = 0;
list_insert_tail(minors_list, job);
/* don't care if dispatch fails, because job->error is 0 */
taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job,
TQ_SLEEP);
if (snapdev == ZFS_SNAPDEV_VISIBLE) {
/*
* traverse snapshots only, do not traverse children,
* and skip the 'dsname'
*/
error = dmu_objset_find((char *)dsname,
zvol_create_snap_minor_cb, (void *)job,
DS_FIND_SNAPSHOTS);
}
} else {
dprintf("zvol_create_minors_cb(): %s is not a zvol name\n",
dsname);
}
return (0);
}
/*
* Create minors for the specified dataset, including children and snapshots.
* Pay attention to the 'snapdev' property and iterate over the snapshots
* only if they are 'visible'. This approach allows one to assure that the
* snapshot metadata is read from disk only if it is needed.
*
* The name can represent a dataset to be recursively scanned for zvols and
* their snapshots, or a single zvol snapshot. If the name represents a
* dataset, the scan is performed in two nested stages:
* - scan the dataset for zvols, and
* - for each zvol, create a minor node, then check if the zvol's snapshots
* are 'visible', and only then iterate over the snapshots if needed
*
* If the name represents a snapshot, a check is performed if the snapshot is
* 'visible' (which also verifies that the parent is a zvol), and if so,
* a minor node for that snapshot is created.
*/
static int
zvol_create_minors_impl(const char *name)
{
int error = 0;
fstrans_cookie_t cookie;
char *atp, *parent;
list_t minors_list;
minors_job_t *job;
if (zvol_inhibit_dev)
return (0);
/*
* This is the list for prefetch jobs. Whenever we found a match
* during dmu_objset_find, we insert a minors_job to the list and do
* taskq_dispatch to parallel prefetch zvol dnodes. Note we don't need
* any lock because all list operation is done on the current thread.
*
* We will use this list to do zvol_create_minor_impl after prefetch
* so we don't have to traverse using dmu_objset_find again.
*/
list_create(&minors_list, sizeof (minors_job_t),
offsetof(minors_job_t, link));
parent = kmem_alloc(MAXPATHLEN, KM_SLEEP);
(void) strlcpy(parent, name, MAXPATHLEN);
if ((atp = strrchr(parent, '@')) != NULL) {
uint64_t snapdev;
*atp = '\0';
error = dsl_prop_get_integer(parent, "snapdev",
&snapdev, NULL);
if (error == 0 && snapdev == ZFS_SNAPDEV_VISIBLE)
error = zvol_create_minor_impl(name);
} else {
cookie = spl_fstrans_mark();
error = dmu_objset_find(parent, zvol_create_minors_cb,
&minors_list, DS_FIND_CHILDREN);
spl_fstrans_unmark(cookie);
}
kmem_free(parent, MAXPATHLEN);
taskq_wait_outstanding(system_taskq, 0);
/*
* Prefetch is completed, we can do zvol_create_minor_impl
* sequentially.
*/
while ((job = list_head(&minors_list)) != NULL) {
list_remove(&minors_list, job);
if (!job->error)
zvol_create_minor_impl(job->name);
strfree(job->name);
kmem_free(job, sizeof (minors_job_t));
}
list_destroy(&minors_list);
return (SET_ERROR(error));
}
/*
* Remove minors for specified dataset including children and snapshots.
*/
static void
zvol_remove_minors_impl(const char *name)
{
zvol_state_t *zv, *zv_next;
int namelen = ((name) ? strlen(name) : 0);
taskqid_t t, tid = TASKQID_INVALID;
list_t free_list;
if (zvol_inhibit_dev)
return;
list_create(&free_list, sizeof (zvol_state_t),
offsetof(zvol_state_t, zv_next));
rw_enter(&zvol_state_lock, RW_WRITER);
for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
zv_next = list_next(&zvol_state_list, zv);
mutex_enter(&zv->zv_state_lock);
if (name == NULL || strcmp(zv->zv_name, name) == 0 ||
(strncmp(zv->zv_name, name, namelen) == 0 &&
(zv->zv_name[namelen] == '/' ||
zv->zv_name[namelen] == '@'))) {
/*
* By holding zv_state_lock here, we guarantee that no
* one is currently using this zv
*/
/* If in use, leave alone */
if (zv->zv_open_count > 0 ||
atomic_read(&zv->zv_suspend_ref)) {
mutex_exit(&zv->zv_state_lock);
continue;
}
zvol_remove(zv);
/*
* Cleared while holding zvol_state_lock as a writer
* which will prevent zvol_open() from opening it.
*/
zv->zv_disk->private_data = NULL;
/* Drop zv_state_lock before zvol_free() */
mutex_exit(&zv->zv_state_lock);
/* Try parallel zv_free, if failed do it in place */
t = taskq_dispatch(system_taskq, zvol_free, zv,
TQ_SLEEP);
if (t == TASKQID_INVALID)
list_insert_head(&free_list, zv);
else
tid = t;
} else {
mutex_exit(&zv->zv_state_lock);
}
}
rw_exit(&zvol_state_lock);
/* Drop zvol_state_lock before calling zvol_free() */
while ((zv = list_head(&free_list)) != NULL) {
list_remove(&free_list, zv);
zvol_free(zv);
}
if (tid != TASKQID_INVALID)
taskq_wait_outstanding(system_taskq, tid);
}
/* Remove minor for this specific volume only */
static void
zvol_remove_minor_impl(const char *name)
{
zvol_state_t *zv = NULL, *zv_next;
if (zvol_inhibit_dev)
return;
rw_enter(&zvol_state_lock, RW_WRITER);
for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
zv_next = list_next(&zvol_state_list, zv);
mutex_enter(&zv->zv_state_lock);
if (strcmp(zv->zv_name, name) == 0) {
/*
* By holding zv_state_lock here, we guarantee that no
* one is currently using this zv
*/
/* If in use, leave alone */
if (zv->zv_open_count > 0 ||
atomic_read(&zv->zv_suspend_ref)) {
mutex_exit(&zv->zv_state_lock);
continue;
}
zvol_remove(zv);
/*
* Cleared while holding zvol_state_lock as a writer
* which will prevent zvol_open() from opening it.
*/
zv->zv_disk->private_data = NULL;
mutex_exit(&zv->zv_state_lock);
break;
} else {
mutex_exit(&zv->zv_state_lock);
}
}
/* Drop zvol_state_lock before calling zvol_free() */
rw_exit(&zvol_state_lock);
if (zv != NULL)
zvol_free(zv);
}
/*
* Rename minors for specified dataset including children and snapshots.
*/
static void
zvol_rename_minors_impl(const char *oldname, const char *newname)
{
zvol_state_t *zv, *zv_next;
int oldnamelen, newnamelen;
if (zvol_inhibit_dev)
return;
oldnamelen = strlen(oldname);
newnamelen = strlen(newname);
rw_enter(&zvol_state_lock, RW_READER);
for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
zv_next = list_next(&zvol_state_list, zv);
mutex_enter(&zv->zv_state_lock);
if (strcmp(zv->zv_name, oldname) == 0) {
zvol_rename_minor(zv, newname);
} else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 &&
(zv->zv_name[oldnamelen] == '/' ||
zv->zv_name[oldnamelen] == '@')) {
char *name = kmem_asprintf("%s%c%s", newname,
zv->zv_name[oldnamelen],
zv->zv_name + oldnamelen + 1);
zvol_rename_minor(zv, name);
strfree(name);
}
mutex_exit(&zv->zv_state_lock);
}
rw_exit(&zvol_state_lock);
}
typedef struct zvol_snapdev_cb_arg {
uint64_t snapdev;
} zvol_snapdev_cb_arg_t;
static int
zvol_set_snapdev_cb(const char *dsname, void *param)
{
zvol_snapdev_cb_arg_t *arg = param;
if (strchr(dsname, '@') == NULL)
return (0);
switch (arg->snapdev) {
case ZFS_SNAPDEV_VISIBLE:
(void) zvol_create_minor_impl(dsname);
break;
case ZFS_SNAPDEV_HIDDEN:
(void) zvol_remove_minor_impl(dsname);
break;
}
return (0);
}
static void
zvol_set_snapdev_impl(char *name, uint64_t snapdev)
{
zvol_snapdev_cb_arg_t arg = {snapdev};
fstrans_cookie_t cookie = spl_fstrans_mark();
/*
* The zvol_set_snapdev_sync() sets snapdev appropriately
* in the dataset hierarchy. Here, we only scan snapshots.
*/
dmu_objset_find(name, zvol_set_snapdev_cb, &arg, DS_FIND_SNAPSHOTS);
spl_fstrans_unmark(cookie);
}
typedef struct zvol_volmode_cb_arg {
uint64_t volmode;
} zvol_volmode_cb_arg_t;
static void
zvol_set_volmode_impl(char *name, uint64_t volmode)
{
fstrans_cookie_t cookie = spl_fstrans_mark();
if (strchr(name, '@') != NULL)
return;
/*
* It's unfortunate we need to remove minors before we create new ones:
* this is necessary because our backing gendisk (zvol_state->zv_disk)
* coule be different when we set, for instance, volmode from "geom"
* to "dev" (or vice versa).
* A possible optimization is to modify our consumers so we don't get
* called when "volmode" does not change.
*/
switch (volmode) {
case ZFS_VOLMODE_NONE:
(void) zvol_remove_minor_impl(name);
break;
case ZFS_VOLMODE_GEOM:
case ZFS_VOLMODE_DEV:
(void) zvol_remove_minor_impl(name);
(void) zvol_create_minor_impl(name);
break;
case ZFS_VOLMODE_DEFAULT:
(void) zvol_remove_minor_impl(name);
if (zvol_volmode == ZFS_VOLMODE_NONE)
break;
else /* if zvol_volmode is invalid defaults to "geom" */
(void) zvol_create_minor_impl(name);
break;
}
spl_fstrans_unmark(cookie);
}
static zvol_task_t *
zvol_task_alloc(zvol_async_op_t op, const char *name1, const char *name2,
uint64_t value)
{
zvol_task_t *task;
char *delim;
/* Never allow tasks on hidden names. */
if (name1[0] == '$')
return (NULL);
task = kmem_zalloc(sizeof (zvol_task_t), KM_SLEEP);
task->op = op;
task->value = value;
delim = strchr(name1, '/');
strlcpy(task->pool, name1, delim ? (delim - name1 + 1) : MAXNAMELEN);
strlcpy(task->name1, name1, MAXNAMELEN);
if (name2 != NULL)
strlcpy(task->name2, name2, MAXNAMELEN);
return (task);
}
static void
zvol_task_free(zvol_task_t *task)
{
kmem_free(task, sizeof (zvol_task_t));
}
/*
* The worker thread function performed asynchronously.
*/
static void
zvol_task_cb(void *param)
{
zvol_task_t *task = (zvol_task_t *)param;
switch (task->op) {
case ZVOL_ASYNC_CREATE_MINORS:
(void) zvol_create_minors_impl(task->name1);
break;
case ZVOL_ASYNC_REMOVE_MINORS:
zvol_remove_minors_impl(task->name1);
break;
case ZVOL_ASYNC_RENAME_MINORS:
zvol_rename_minors_impl(task->name1, task->name2);
break;
case ZVOL_ASYNC_SET_SNAPDEV:
zvol_set_snapdev_impl(task->name1, task->value);
break;
case ZVOL_ASYNC_SET_VOLMODE:
zvol_set_volmode_impl(task->name1, task->value);
break;
default:
VERIFY(0);
break;
}
zvol_task_free(task);
}
typedef struct zvol_set_prop_int_arg {
const char *zsda_name;
uint64_t zsda_value;
zprop_source_t zsda_source;
dmu_tx_t *zsda_tx;
} zvol_set_prop_int_arg_t;
/*
* Sanity check the dataset for safe use by the sync task. No additional
* conditions are imposed.
*/
static int
zvol_set_snapdev_check(void *arg, dmu_tx_t *tx)
{
zvol_set_prop_int_arg_t *zsda = arg;
dsl_pool_t *dp = dmu_tx_pool(tx);
dsl_dir_t *dd;
int error;
error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL);
if (error != 0)
return (error);
dsl_dir_rele(dd, FTAG);
return (error);
}
/* ARGSUSED */
static int
zvol_set_snapdev_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
{
char dsname[MAXNAMELEN];
zvol_task_t *task;
uint64_t snapdev;
dsl_dataset_name(ds, dsname);
if (dsl_prop_get_int_ds(ds, "snapdev", &snapdev) != 0)
return (0);
task = zvol_task_alloc(ZVOL_ASYNC_SET_SNAPDEV, dsname, NULL, snapdev);
if (task == NULL)
return (0);
(void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb,
task, TQ_SLEEP);
return (0);
}
/*
* Traverse all child datasets and apply snapdev appropriately.
* We call dsl_prop_set_sync_impl() here to set the value only on the toplevel
* dataset and read the effective "snapdev" on every child in the callback
* function: this is because the value is not guaranteed to be the same in the
* whole dataset hierarchy.
*/
static void
zvol_set_snapdev_sync(void *arg, dmu_tx_t *tx)
{
zvol_set_prop_int_arg_t *zsda = arg;
dsl_pool_t *dp = dmu_tx_pool(tx);
dsl_dir_t *dd;
dsl_dataset_t *ds;
int error;
VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL));
zsda->zsda_tx = tx;
error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds);
if (error == 0) {
dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_SNAPDEV),
zsda->zsda_source, sizeof (zsda->zsda_value), 1,
&zsda->zsda_value, zsda->zsda_tx);
dsl_dataset_rele(ds, FTAG);
}
dmu_objset_find_dp(dp, dd->dd_object, zvol_set_snapdev_sync_cb,
zsda, DS_FIND_CHILDREN);
dsl_dir_rele(dd, FTAG);
}
int
zvol_set_snapdev(const char *ddname, zprop_source_t source, uint64_t snapdev)
{
zvol_set_prop_int_arg_t zsda;
zsda.zsda_name = ddname;
zsda.zsda_source = source;
zsda.zsda_value = snapdev;
return (dsl_sync_task(ddname, zvol_set_snapdev_check,
zvol_set_snapdev_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE));
}
/*
* Sanity check the dataset for safe use by the sync task. No additional
* conditions are imposed.
*/
static int
zvol_set_volmode_check(void *arg, dmu_tx_t *tx)
{
zvol_set_prop_int_arg_t *zsda = arg;
dsl_pool_t *dp = dmu_tx_pool(tx);
dsl_dir_t *dd;
int error;
error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL);
if (error != 0)
return (error);
dsl_dir_rele(dd, FTAG);
return (error);
}
/* ARGSUSED */
static int
zvol_set_volmode_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
{
char dsname[MAXNAMELEN];
zvol_task_t *task;
uint64_t volmode;
dsl_dataset_name(ds, dsname);
if (dsl_prop_get_int_ds(ds, "volmode", &volmode) != 0)
return (0);
task = zvol_task_alloc(ZVOL_ASYNC_SET_VOLMODE, dsname, NULL, volmode);
if (task == NULL)
return (0);
(void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb,
task, TQ_SLEEP);
return (0);
}
/*
* Traverse all child datasets and apply volmode appropriately.
* We call dsl_prop_set_sync_impl() here to set the value only on the toplevel
* dataset and read the effective "volmode" on every child in the callback
* function: this is because the value is not guaranteed to be the same in the
* whole dataset hierarchy.
*/
static void
zvol_set_volmode_sync(void *arg, dmu_tx_t *tx)
{
zvol_set_prop_int_arg_t *zsda = arg;
dsl_pool_t *dp = dmu_tx_pool(tx);
dsl_dir_t *dd;
dsl_dataset_t *ds;
int error;
VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL));
zsda->zsda_tx = tx;
error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds);
if (error == 0) {
dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_VOLMODE),
zsda->zsda_source, sizeof (zsda->zsda_value), 1,
&zsda->zsda_value, zsda->zsda_tx);
dsl_dataset_rele(ds, FTAG);
}
dmu_objset_find_dp(dp, dd->dd_object, zvol_set_volmode_sync_cb,
zsda, DS_FIND_CHILDREN);
dsl_dir_rele(dd, FTAG);
}
int
zvol_set_volmode(const char *ddname, zprop_source_t source, uint64_t volmode)
{
zvol_set_prop_int_arg_t zsda;
zsda.zsda_name = ddname;
zsda.zsda_source = source;
zsda.zsda_value = volmode;
return (dsl_sync_task(ddname, zvol_set_volmode_check,
zvol_set_volmode_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE));
}
void
zvol_create_minors(spa_t *spa, const char *name, boolean_t async)
{
zvol_task_t *task;
taskqid_t id;
task = zvol_task_alloc(ZVOL_ASYNC_CREATE_MINORS, name, NULL, ~0ULL);
if (task == NULL)
return;
id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
if ((async == B_FALSE) && (id != TASKQID_INVALID))
taskq_wait_id(spa->spa_zvol_taskq, id);
}
void
zvol_remove_minors(spa_t *spa, const char *name, boolean_t async)
{
zvol_task_t *task;
taskqid_t id;
task = zvol_task_alloc(ZVOL_ASYNC_REMOVE_MINORS, name, NULL, ~0ULL);
if (task == NULL)
return;
id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
if ((async == B_FALSE) && (id != TASKQID_INVALID))
taskq_wait_id(spa->spa_zvol_taskq, id);
}
void
zvol_rename_minors(spa_t *spa, const char *name1, const char *name2,
boolean_t async)
{
zvol_task_t *task;
taskqid_t id;
task = zvol_task_alloc(ZVOL_ASYNC_RENAME_MINORS, name1, name2, ~0ULL);
if (task == NULL)
return;
id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
if ((async == B_FALSE) && (id != TASKQID_INVALID))
taskq_wait_id(spa->spa_zvol_taskq, id);
}
int
zvol_init(void)
{
int threads = MIN(MAX(zvol_threads, 1), 1024);
int i, error;
list_create(&zvol_state_list, sizeof (zvol_state_t),
offsetof(zvol_state_t, zv_next));
rw_init(&zvol_state_lock, NULL, RW_DEFAULT, NULL);
ida_init(&zvol_ida);
zvol_taskq = taskq_create(ZVOL_DRIVER, threads, maxclsyspri,
threads * 2, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
if (zvol_taskq == NULL) {
printk(KERN_INFO "ZFS: taskq_create() failed\n");
error = -ENOMEM;
goto out;
}
zvol_htable = kmem_alloc(ZVOL_HT_SIZE * sizeof (struct hlist_head),
KM_SLEEP);
if (!zvol_htable) {
error = -ENOMEM;
goto out_taskq;
}
for (i = 0; i < ZVOL_HT_SIZE; i++)
INIT_HLIST_HEAD(&zvol_htable[i]);
error = register_blkdev(zvol_major, ZVOL_DRIVER);
if (error) {
printk(KERN_INFO "ZFS: register_blkdev() failed %d\n", error);
goto out_free;
}
blk_register_region(MKDEV(zvol_major, 0), 1UL << MINORBITS,
THIS_MODULE, zvol_probe, NULL, NULL);
return (0);
out_free:
kmem_free(zvol_htable, ZVOL_HT_SIZE * sizeof (struct hlist_head));
out_taskq:
taskq_destroy(zvol_taskq);
out:
ida_destroy(&zvol_ida);
rw_destroy(&zvol_state_lock);
list_destroy(&zvol_state_list);
return (SET_ERROR(error));
}
void
zvol_fini(void)
{
zvol_remove_minors_impl(NULL);
blk_unregister_region(MKDEV(zvol_major, 0), 1UL << MINORBITS);
unregister_blkdev(zvol_major, ZVOL_DRIVER);
kmem_free(zvol_htable, ZVOL_HT_SIZE * sizeof (struct hlist_head));
taskq_destroy(zvol_taskq);
list_destroy(&zvol_state_list);
rw_destroy(&zvol_state_lock);
ida_destroy(&zvol_ida);
}
/* BEGIN CSTYLED */
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, "Max number of threads to handle I/O requests");
module_param(zvol_request_sync, uint, 0644);
MODULE_PARM_DESC(zvol_request_sync, "Synchronously handle bio requests");
module_param(zvol_max_discard_blocks, ulong, 0444);
MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard");
module_param(zvol_prefetch_bytes, uint, 0644);
MODULE_PARM_DESC(zvol_prefetch_bytes, "Prefetch N bytes at zvol start+end");
module_param(zvol_volmode, uint, 0644);
MODULE_PARM_DESC(zvol_volmode, "Default volmode property value");
/* END CSTYLED */
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