4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (C) 2008-2010 Lawrence Livermore National Security, LLC.
23 * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
24 * Rewritten for Linux by Brian Behlendorf <behlendorf1@llnl.gov>.
27 * ZFS volume emulation driver.
29 * Makes a DMU object look like a volume of arbitrary size, up to 2^64 bytes.
30 * Volumes are accessed through the symbolic links named:
32 * /dev/<pool_name>/<dataset_name>
34 * Volumes are persistent through reboot and module load. No user command
35 * needs to be run before opening and using a device.
39 #include <sys/dmu_traverse.h>
40 #include <sys/dsl_dataset.h>
41 #include <sys/dsl_prop.h>
43 #include <sys/zfeature.h>
44 #include <sys/zil_impl.h>
46 #include <sys/zfs_rlock.h>
47 #include <sys/zfs_znode.h>
49 #include <linux/blkdev_compat.h>
51 unsigned int zvol_inhibit_dev
= 0;
52 unsigned int zvol_major
= ZVOL_MAJOR
;
53 unsigned int zvol_prefetch_bytes
= (128 * 1024);
54 unsigned long zvol_max_discard_blocks
= 16384;
56 static kmutex_t zvol_state_lock
;
57 static list_t zvol_state_list
;
58 static char *zvol_tag
= "zvol_tag";
61 * The in-core state of each volume.
63 typedef struct zvol_state
{
64 char zv_name
[MAXNAMELEN
]; /* name */
65 uint64_t zv_volsize
; /* advertised space */
66 uint64_t zv_volblocksize
; /* volume block size */
67 objset_t
*zv_objset
; /* objset handle */
68 uint32_t zv_flags
; /* ZVOL_* flags */
69 uint32_t zv_open_count
; /* open counts */
70 uint32_t zv_changed
; /* disk changed */
71 zilog_t
*zv_zilog
; /* ZIL handle */
72 znode_t zv_znode
; /* for range locking */
73 dmu_buf_t
*zv_dbuf
; /* bonus handle */
74 dev_t zv_dev
; /* device id */
75 struct gendisk
*zv_disk
; /* generic disk */
76 struct request_queue
*zv_queue
; /* request queue */
77 spinlock_t zv_lock
; /* request queue lock */
78 list_node_t zv_next
; /* next zvol_state_t linkage */
81 #define ZVOL_RDONLY 0x1
84 * Find the next available range of ZVOL_MINORS minor numbers. The
85 * zvol_state_list is kept in ascending minor order so we simply need
86 * to scan the list for the first gap in the sequence. This allows us
87 * to recycle minor number as devices are created and removed.
90 zvol_find_minor(unsigned *minor
)
95 ASSERT(MUTEX_HELD(&zvol_state_lock
));
96 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
97 zv
= list_next(&zvol_state_list
, zv
), *minor
+= ZVOL_MINORS
) {
98 if (MINOR(zv
->zv_dev
) != MINOR(*minor
))
102 /* All minors are in use */
103 if (*minor
>= (1 << MINORBITS
))
104 return (SET_ERROR(ENXIO
));
110 * Find a zvol_state_t given the full major+minor dev_t.
112 static zvol_state_t
*
113 zvol_find_by_dev(dev_t dev
)
117 ASSERT(MUTEX_HELD(&zvol_state_lock
));
118 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
119 zv
= list_next(&zvol_state_list
, zv
)) {
120 if (zv
->zv_dev
== dev
)
128 * Find a zvol_state_t given the name provided at zvol_alloc() time.
130 static zvol_state_t
*
131 zvol_find_by_name(const char *name
)
135 ASSERT(MUTEX_HELD(&zvol_state_lock
));
136 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
137 zv
= list_next(&zvol_state_list
, zv
)) {
138 if (strncmp(zv
->zv_name
, name
, MAXNAMELEN
) == 0)
147 * Given a path, return TRUE if path is a ZVOL.
150 zvol_is_zvol(const char *device
)
152 struct block_device
*bdev
;
155 bdev
= lookup_bdev(device
);
159 major
= MAJOR(bdev
->bd_dev
);
162 if (major
== zvol_major
)
169 * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation.
172 zvol_create_cb(objset_t
*os
, void *arg
, cred_t
*cr
, dmu_tx_t
*tx
)
174 zfs_creat_t
*zct
= arg
;
175 nvlist_t
*nvprops
= zct
->zct_props
;
177 uint64_t volblocksize
, volsize
;
179 VERIFY(nvlist_lookup_uint64(nvprops
,
180 zfs_prop_to_name(ZFS_PROP_VOLSIZE
), &volsize
) == 0);
181 if (nvlist_lookup_uint64(nvprops
,
182 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE
), &volblocksize
) != 0)
183 volblocksize
= zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE
);
186 * These properties must be removed from the list so the generic
187 * property setting step won't apply to them.
189 VERIFY(nvlist_remove_all(nvprops
,
190 zfs_prop_to_name(ZFS_PROP_VOLSIZE
)) == 0);
191 (void) nvlist_remove_all(nvprops
,
192 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE
));
194 error
= dmu_object_claim(os
, ZVOL_OBJ
, DMU_OT_ZVOL
, volblocksize
,
198 error
= zap_create_claim(os
, ZVOL_ZAP_OBJ
, DMU_OT_ZVOL_PROP
,
202 error
= zap_update(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
, tx
);
207 * ZFS_IOC_OBJSET_STATS entry point.
210 zvol_get_stats(objset_t
*os
, nvlist_t
*nv
)
213 dmu_object_info_t
*doi
;
216 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &val
);
218 return (SET_ERROR(error
));
220 dsl_prop_nvlist_add_uint64(nv
, ZFS_PROP_VOLSIZE
, val
);
221 doi
= kmem_alloc(sizeof (dmu_object_info_t
), KM_SLEEP
);
222 error
= dmu_object_info(os
, ZVOL_OBJ
, doi
);
225 dsl_prop_nvlist_add_uint64(nv
, ZFS_PROP_VOLBLOCKSIZE
,
226 doi
->doi_data_block_size
);
229 kmem_free(doi
, sizeof (dmu_object_info_t
));
231 return (SET_ERROR(error
));
235 zvol_size_changed(zvol_state_t
*zv
, uint64_t volsize
)
237 struct block_device
*bdev
;
239 bdev
= bdget_disk(zv
->zv_disk
, 0);
244 * Added check_disk_size_change() helper function.
246 #ifdef HAVE_CHECK_DISK_SIZE_CHANGE
247 set_capacity(zv
->zv_disk
, volsize
>> 9);
248 zv
->zv_volsize
= volsize
;
249 check_disk_size_change(zv
->zv_disk
, bdev
);
251 zv
->zv_volsize
= volsize
;
253 (void) check_disk_change(bdev
);
254 #endif /* HAVE_CHECK_DISK_SIZE_CHANGE */
260 * Sanity check volume size.
263 zvol_check_volsize(uint64_t volsize
, uint64_t blocksize
)
266 return (SET_ERROR(EINVAL
));
268 if (volsize
% blocksize
!= 0)
269 return (SET_ERROR(EINVAL
));
272 if (volsize
- 1 > MAXOFFSET_T
)
273 return (SET_ERROR(EOVERFLOW
));
279 * Ensure the zap is flushed then inform the VFS of the capacity change.
282 zvol_update_volsize(uint64_t volsize
, objset_t
*os
)
287 ASSERT(MUTEX_HELD(&zvol_state_lock
));
289 tx
= dmu_tx_create(os
);
290 dmu_tx_hold_zap(tx
, ZVOL_ZAP_OBJ
, TRUE
, NULL
);
291 error
= dmu_tx_assign(tx
, TXG_WAIT
);
294 return (SET_ERROR(error
));
297 error
= zap_update(os
, ZVOL_ZAP_OBJ
, "size", 8, 1,
302 error
= dmu_free_long_range(os
,
303 ZVOL_OBJ
, volsize
, DMU_OBJECT_END
);
309 zvol_update_live_volsize(zvol_state_t
*zv
, uint64_t volsize
)
311 zvol_size_changed(zv
, volsize
);
314 * We should post a event here describing the expansion. However,
315 * the zfs_ereport_post() interface doesn't nicely support posting
316 * events for zvols, it assumes events relate to vdevs or zios.
323 * Set ZFS_PROP_VOLSIZE set entry point.
326 zvol_set_volsize(const char *name
, uint64_t volsize
)
328 zvol_state_t
*zv
= NULL
;
331 dmu_object_info_t
*doi
;
333 boolean_t owned
= B_FALSE
;
335 error
= dsl_prop_get_integer(name
,
336 zfs_prop_to_name(ZFS_PROP_READONLY
), &readonly
, NULL
);
338 return (SET_ERROR(error
));
340 return (SET_ERROR(EROFS
));
342 mutex_enter(&zvol_state_lock
);
343 zv
= zvol_find_by_name(name
);
345 if (zv
== NULL
|| zv
->zv_objset
== NULL
) {
346 if ((error
= dmu_objset_own(name
, DMU_OST_ZVOL
, B_FALSE
,
348 mutex_exit(&zvol_state_lock
);
349 return (SET_ERROR(error
));
358 doi
= kmem_alloc(sizeof (dmu_object_info_t
), KM_SLEEP
);
360 if ((error
= dmu_object_info(os
, ZVOL_OBJ
, doi
)) ||
361 (error
= zvol_check_volsize(volsize
, doi
->doi_data_block_size
)))
364 error
= zvol_update_volsize(volsize
, os
);
365 kmem_free(doi
, sizeof (dmu_object_info_t
));
367 if (error
== 0 && zv
!= NULL
)
368 error
= zvol_update_live_volsize(zv
, volsize
);
371 dmu_objset_disown(os
, FTAG
);
373 zv
->zv_objset
= NULL
;
375 mutex_exit(&zvol_state_lock
);
380 * Sanity check volume block size.
383 zvol_check_volblocksize(const char *name
, uint64_t volblocksize
)
385 /* Record sizes above 128k need the feature to be enabled */
386 if (volblocksize
> SPA_OLD_MAXBLOCKSIZE
) {
390 if ((error
= spa_open(name
, &spa
, FTAG
)) != 0)
393 if (!spa_feature_is_enabled(spa
, SPA_FEATURE_LARGE_BLOCKS
)) {
394 spa_close(spa
, FTAG
);
395 return (SET_ERROR(ENOTSUP
));
399 * We don't allow setting the property above 1MB,
400 * unless the tunable has been changed.
402 if (volblocksize
> zfs_max_recordsize
)
403 return (SET_ERROR(EDOM
));
405 spa_close(spa
, FTAG
);
408 if (volblocksize
< SPA_MINBLOCKSIZE
||
409 volblocksize
> SPA_MAXBLOCKSIZE
||
411 return (SET_ERROR(EDOM
));
417 * Set ZFS_PROP_VOLBLOCKSIZE set entry point.
420 zvol_set_volblocksize(const char *name
, uint64_t volblocksize
)
426 mutex_enter(&zvol_state_lock
);
428 zv
= zvol_find_by_name(name
);
430 error
= SET_ERROR(ENXIO
);
434 if (zv
->zv_flags
& ZVOL_RDONLY
) {
435 error
= SET_ERROR(EROFS
);
439 tx
= dmu_tx_create(zv
->zv_objset
);
440 dmu_tx_hold_bonus(tx
, ZVOL_OBJ
);
441 error
= dmu_tx_assign(tx
, TXG_WAIT
);
445 error
= dmu_object_set_blocksize(zv
->zv_objset
, ZVOL_OBJ
,
446 volblocksize
, 0, tx
);
447 if (error
== ENOTSUP
)
448 error
= SET_ERROR(EBUSY
);
451 zv
->zv_volblocksize
= volblocksize
;
454 mutex_exit(&zvol_state_lock
);
456 return (SET_ERROR(error
));
460 * Replay a TX_WRITE ZIL transaction that didn't get committed
461 * after a system failure
464 zvol_replay_write(zvol_state_t
*zv
, lr_write_t
*lr
, boolean_t byteswap
)
466 objset_t
*os
= zv
->zv_objset
;
467 char *data
= (char *)(lr
+ 1); /* data follows lr_write_t */
468 uint64_t off
= lr
->lr_offset
;
469 uint64_t len
= lr
->lr_length
;
474 byteswap_uint64_array(lr
, sizeof (*lr
));
476 tx
= dmu_tx_create(os
);
477 dmu_tx_hold_write(tx
, ZVOL_OBJ
, off
, len
);
478 error
= dmu_tx_assign(tx
, TXG_WAIT
);
482 dmu_write(os
, ZVOL_OBJ
, off
, len
, data
, tx
);
486 return (SET_ERROR(error
));
490 zvol_replay_err(zvol_state_t
*zv
, lr_t
*lr
, boolean_t byteswap
)
492 return (SET_ERROR(ENOTSUP
));
496 * Callback vectors for replaying records.
497 * Only TX_WRITE is needed for zvol.
499 zil_replay_func_t zvol_replay_vector
[TX_MAX_TYPE
] = {
500 (zil_replay_func_t
)zvol_replay_err
, /* no such transaction type */
501 (zil_replay_func_t
)zvol_replay_err
, /* TX_CREATE */
502 (zil_replay_func_t
)zvol_replay_err
, /* TX_MKDIR */
503 (zil_replay_func_t
)zvol_replay_err
, /* TX_MKXATTR */
504 (zil_replay_func_t
)zvol_replay_err
, /* TX_SYMLINK */
505 (zil_replay_func_t
)zvol_replay_err
, /* TX_REMOVE */
506 (zil_replay_func_t
)zvol_replay_err
, /* TX_RMDIR */
507 (zil_replay_func_t
)zvol_replay_err
, /* TX_LINK */
508 (zil_replay_func_t
)zvol_replay_err
, /* TX_RENAME */
509 (zil_replay_func_t
)zvol_replay_write
, /* TX_WRITE */
510 (zil_replay_func_t
)zvol_replay_err
, /* TX_TRUNCATE */
511 (zil_replay_func_t
)zvol_replay_err
, /* TX_SETATTR */
512 (zil_replay_func_t
)zvol_replay_err
, /* TX_ACL */
516 * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
518 * We store data in the log buffers if it's small enough.
519 * Otherwise we will later flush the data out via dmu_sync().
521 ssize_t zvol_immediate_write_sz
= 32768;
524 zvol_log_write(zvol_state_t
*zv
, dmu_tx_t
*tx
, uint64_t offset
,
525 uint64_t size
, int sync
)
527 uint32_t blocksize
= zv
->zv_volblocksize
;
528 zilog_t
*zilog
= zv
->zv_zilog
;
530 ssize_t immediate_write_sz
;
532 if (zil_replaying(zilog
, tx
))
535 immediate_write_sz
= (zilog
->zl_logbias
== ZFS_LOGBIAS_THROUGHPUT
)
536 ? 0 : zvol_immediate_write_sz
;
537 slogging
= spa_has_slogs(zilog
->zl_spa
) &&
538 (zilog
->zl_logbias
== ZFS_LOGBIAS_LATENCY
);
544 itx_wr_state_t write_state
;
547 * Unlike zfs_log_write() we can be called with
548 * up to DMU_MAX_ACCESS/2 (5MB) writes.
550 if (blocksize
> immediate_write_sz
&& !slogging
&&
551 size
>= blocksize
&& offset
% blocksize
== 0) {
552 write_state
= WR_INDIRECT
; /* uses dmu_sync */
555 write_state
= WR_COPIED
;
556 len
= MIN(ZIL_MAX_LOG_DATA
, size
);
558 write_state
= WR_NEED_COPY
;
559 len
= MIN(ZIL_MAX_LOG_DATA
, size
);
562 itx
= zil_itx_create(TX_WRITE
, sizeof (*lr
) +
563 (write_state
== WR_COPIED
? len
: 0));
564 lr
= (lr_write_t
*)&itx
->itx_lr
;
565 if (write_state
== WR_COPIED
&& dmu_read(zv
->zv_objset
,
566 ZVOL_OBJ
, offset
, len
, lr
+1, DMU_READ_NO_PREFETCH
) != 0) {
567 zil_itx_destroy(itx
);
568 itx
= zil_itx_create(TX_WRITE
, sizeof (*lr
));
569 lr
= (lr_write_t
*)&itx
->itx_lr
;
570 write_state
= WR_NEED_COPY
;
573 itx
->itx_wr_state
= write_state
;
574 if (write_state
== WR_NEED_COPY
)
576 lr
->lr_foid
= ZVOL_OBJ
;
577 lr
->lr_offset
= offset
;
580 BP_ZERO(&lr
->lr_blkptr
);
582 itx
->itx_private
= zv
;
583 itx
->itx_sync
= sync
;
585 (void) zil_itx_assign(zilog
, itx
, tx
);
593 zvol_write(struct bio
*bio
)
595 zvol_state_t
*zv
= bio
->bi_bdev
->bd_disk
->private_data
;
596 uint64_t offset
= BIO_BI_SECTOR(bio
) << 9;
597 uint64_t size
= BIO_BI_SIZE(bio
);
602 if (bio
->bi_rw
& VDEV_REQ_FLUSH
)
603 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
606 * Some requests are just for flush and nothing else.
611 rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_WRITER
);
613 tx
= dmu_tx_create(zv
->zv_objset
);
614 dmu_tx_hold_write(tx
, ZVOL_OBJ
, offset
, size
);
616 /* This will only fail for ENOSPC */
617 error
= dmu_tx_assign(tx
, TXG_WAIT
);
620 zfs_range_unlock(rl
);
624 error
= dmu_write_bio(zv
->zv_objset
, ZVOL_OBJ
, bio
, tx
);
626 zvol_log_write(zv
, tx
, offset
, size
,
627 !!(bio
->bi_rw
& VDEV_REQ_FUA
));
630 zfs_range_unlock(rl
);
632 if ((bio
->bi_rw
& VDEV_REQ_FUA
) ||
633 zv
->zv_objset
->os_sync
== ZFS_SYNC_ALWAYS
)
634 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
641 zvol_discard(struct bio
*bio
)
643 zvol_state_t
*zv
= bio
->bi_bdev
->bd_disk
->private_data
;
644 uint64_t start
= BIO_BI_SECTOR(bio
) << 9;
645 uint64_t size
= BIO_BI_SIZE(bio
);
646 uint64_t end
= start
+ size
;
650 if (end
> zv
->zv_volsize
)
651 return (SET_ERROR(EIO
));
654 * Align the request to volume block boundaries when REQ_SECURE is
655 * available, but not requested. If we don't, then this will force
656 * dnode_free_range() to zero out the unaligned parts, which is slow
657 * (read-modify-write) and useless since we are not freeing any space
658 * by doing so. Kernels that do not support REQ_SECURE (2.6.32 through
659 * 2.6.35) will not receive this optimization.
662 if (!(bio
->bi_rw
& REQ_SECURE
)) {
663 start
= P2ROUNDUP(start
, zv
->zv_volblocksize
);
664 end
= P2ALIGN(end
, zv
->zv_volblocksize
);
671 rl
= zfs_range_lock(&zv
->zv_znode
, start
, size
, RL_WRITER
);
673 error
= dmu_free_long_range(zv
->zv_objset
, ZVOL_OBJ
, start
, size
);
676 * TODO: maybe we should add the operation to the log.
679 zfs_range_unlock(rl
);
685 zvol_read(struct bio
*bio
)
687 zvol_state_t
*zv
= bio
->bi_bdev
->bd_disk
->private_data
;
688 uint64_t offset
= BIO_BI_SECTOR(bio
) << 9;
689 uint64_t len
= BIO_BI_SIZE(bio
);
697 rl
= zfs_range_lock(&zv
->zv_znode
, offset
, len
, RL_READER
);
699 error
= dmu_read_bio(zv
->zv_objset
, ZVOL_OBJ
, bio
);
701 zfs_range_unlock(rl
);
703 /* convert checksum errors into IO errors */
705 error
= SET_ERROR(EIO
);
710 static MAKE_REQUEST_FN_RET
711 zvol_request(struct request_queue
*q
, struct bio
*bio
)
713 zvol_state_t
*zv
= q
->queuedata
;
714 fstrans_cookie_t cookie
= spl_fstrans_mark();
715 uint64_t offset
= BIO_BI_SECTOR(bio
);
716 unsigned int sectors
= bio_sectors(bio
);
717 int rw
= bio_data_dir(bio
);
718 #ifdef HAVE_GENERIC_IO_ACCT
719 unsigned long start
= jiffies
;
723 if (bio_has_data(bio
) && offset
+ sectors
>
724 get_capacity(zv
->zv_disk
)) {
726 "%s: bad access: block=%llu, count=%lu\n",
727 zv
->zv_disk
->disk_name
,
728 (long long unsigned)offset
,
729 (long unsigned)sectors
);
730 error
= SET_ERROR(EIO
);
734 generic_start_io_acct(rw
, sectors
, &zv
->zv_disk
->part0
);
737 if (unlikely(zv
->zv_flags
& ZVOL_RDONLY
)) {
738 error
= SET_ERROR(EROFS
);
742 if (bio
->bi_rw
& VDEV_REQ_DISCARD
) {
743 error
= zvol_discard(bio
);
747 error
= zvol_write(bio
);
749 error
= zvol_read(bio
);
752 generic_end_io_acct(rw
, &zv
->zv_disk
->part0
, start
);
754 bio_endio(bio
, -error
);
755 spl_fstrans_unmark(cookie
);
756 #ifdef HAVE_MAKE_REQUEST_FN_RET_INT
762 zvol_get_done(zgd_t
*zgd
, int error
)
765 dmu_buf_rele(zgd
->zgd_db
, zgd
);
767 zfs_range_unlock(zgd
->zgd_rl
);
769 if (error
== 0 && zgd
->zgd_bp
)
770 zil_add_block(zgd
->zgd_zilog
, zgd
->zgd_bp
);
772 kmem_free(zgd
, sizeof (zgd_t
));
776 * Get data to generate a TX_WRITE intent log record.
779 zvol_get_data(void *arg
, lr_write_t
*lr
, char *buf
, zio_t
*zio
)
781 zvol_state_t
*zv
= arg
;
782 objset_t
*os
= zv
->zv_objset
;
783 uint64_t object
= ZVOL_OBJ
;
784 uint64_t offset
= lr
->lr_offset
;
785 uint64_t size
= lr
->lr_length
;
786 blkptr_t
*bp
= &lr
->lr_blkptr
;
794 zgd
= (zgd_t
*)kmem_zalloc(sizeof (zgd_t
), KM_SLEEP
);
795 zgd
->zgd_zilog
= zv
->zv_zilog
;
796 zgd
->zgd_rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_READER
);
799 * Write records come in two flavors: immediate and indirect.
800 * For small writes it's cheaper to store the data with the
801 * log record (immediate); for large writes it's cheaper to
802 * sync the data and get a pointer to it (indirect) so that
803 * we don't have to write the data twice.
805 if (buf
!= NULL
) { /* immediate write */
806 error
= dmu_read(os
, object
, offset
, size
, buf
,
807 DMU_READ_NO_PREFETCH
);
809 size
= zv
->zv_volblocksize
;
810 offset
= P2ALIGN_TYPED(offset
, size
, uint64_t);
811 error
= dmu_buf_hold(os
, object
, offset
, zgd
, &db
,
812 DMU_READ_NO_PREFETCH
);
814 blkptr_t
*obp
= dmu_buf_get_blkptr(db
);
816 ASSERT(BP_IS_HOLE(bp
));
821 zgd
->zgd_bp
= &lr
->lr_blkptr
;
824 ASSERT(db
->db_offset
== offset
);
825 ASSERT(db
->db_size
== size
);
827 error
= dmu_sync(zio
, lr
->lr_common
.lrc_txg
,
835 zvol_get_done(zgd
, error
);
837 return (SET_ERROR(error
));
841 * The zvol_state_t's are inserted in increasing MINOR(dev_t) order.
844 zvol_insert(zvol_state_t
*zv_insert
)
846 zvol_state_t
*zv
= NULL
;
848 ASSERT(MUTEX_HELD(&zvol_state_lock
));
849 ASSERT3U(MINOR(zv_insert
->zv_dev
) & ZVOL_MINOR_MASK
, ==, 0);
850 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
851 zv
= list_next(&zvol_state_list
, zv
)) {
852 if (MINOR(zv
->zv_dev
) > MINOR(zv_insert
->zv_dev
))
856 list_insert_before(&zvol_state_list
, zv
, zv_insert
);
860 * Simply remove the zvol from to list of zvols.
863 zvol_remove(zvol_state_t
*zv_remove
)
865 ASSERT(MUTEX_HELD(&zvol_state_lock
));
866 list_remove(&zvol_state_list
, zv_remove
);
870 zvol_first_open(zvol_state_t
*zv
)
879 * In all other cases the spa_namespace_lock is taken before the
880 * bdev->bd_mutex lock. But in this case the Linux __blkdev_get()
881 * function calls fops->open() with the bdev->bd_mutex lock held.
883 * To avoid a potential lock inversion deadlock we preemptively
884 * try to take the spa_namespace_lock(). Normally it will not
885 * be contended and this is safe because spa_open_common() handles
886 * the case where the caller already holds the spa_namespace_lock.
888 * When it is contended we risk a lock inversion if we were to
889 * block waiting for the lock. Luckily, the __blkdev_get()
890 * function allows us to return -ERESTARTSYS which will result in
891 * bdev->bd_mutex being dropped, reacquired, and fops->open() being
892 * called again. This process can be repeated safely until both
893 * locks are acquired.
895 if (!mutex_owned(&spa_namespace_lock
)) {
896 locked
= mutex_tryenter(&spa_namespace_lock
);
898 return (-SET_ERROR(ERESTARTSYS
));
901 error
= dsl_prop_get_integer(zv
->zv_name
, "readonly", &ro
, NULL
);
905 /* lie and say we're read-only */
906 error
= dmu_objset_own(zv
->zv_name
, DMU_OST_ZVOL
, 1, zvol_tag
, &os
);
910 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
);
912 dmu_objset_disown(os
, zvol_tag
);
917 error
= dmu_bonus_hold(os
, ZVOL_OBJ
, zvol_tag
, &zv
->zv_dbuf
);
919 dmu_objset_disown(os
, zvol_tag
);
923 set_capacity(zv
->zv_disk
, volsize
>> 9);
924 zv
->zv_volsize
= volsize
;
925 zv
->zv_zilog
= zil_open(os
, zvol_get_data
);
927 if (ro
|| dmu_objset_is_snapshot(os
) ||
928 !spa_writeable(dmu_objset_spa(os
))) {
929 set_disk_ro(zv
->zv_disk
, 1);
930 zv
->zv_flags
|= ZVOL_RDONLY
;
932 set_disk_ro(zv
->zv_disk
, 0);
933 zv
->zv_flags
&= ~ZVOL_RDONLY
;
938 mutex_exit(&spa_namespace_lock
);
940 return (SET_ERROR(-error
));
944 zvol_last_close(zvol_state_t
*zv
)
946 zil_close(zv
->zv_zilog
);
949 dmu_buf_rele(zv
->zv_dbuf
, zvol_tag
);
955 if (dsl_dataset_is_dirty(dmu_objset_ds(zv
->zv_objset
)) &&
956 !(zv
->zv_flags
& ZVOL_RDONLY
))
957 txg_wait_synced(dmu_objset_pool(zv
->zv_objset
), 0);
958 (void) dmu_objset_evict_dbufs(zv
->zv_objset
);
960 dmu_objset_disown(zv
->zv_objset
, zvol_tag
);
961 zv
->zv_objset
= NULL
;
965 zvol_open(struct block_device
*bdev
, fmode_t flag
)
967 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
968 int error
= 0, drop_mutex
= 0;
971 * If the caller is already holding the mutex do not take it
972 * again, this will happen as part of zvol_create_minor().
973 * Once add_disk() is called the device is live and the kernel
974 * will attempt to open it to read the partition information.
976 if (!mutex_owned(&zvol_state_lock
)) {
977 mutex_enter(&zvol_state_lock
);
981 ASSERT3P(zv
, !=, NULL
);
983 if (zv
->zv_open_count
== 0) {
984 error
= zvol_first_open(zv
);
989 if ((flag
& FMODE_WRITE
) && (zv
->zv_flags
& ZVOL_RDONLY
)) {
997 if (zv
->zv_open_count
== 0)
1002 mutex_exit(&zvol_state_lock
);
1004 check_disk_change(bdev
);
1006 return (SET_ERROR(error
));
1009 #ifdef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
1014 zvol_release(struct gendisk
*disk
, fmode_t mode
)
1016 zvol_state_t
*zv
= disk
->private_data
;
1019 if (!mutex_owned(&zvol_state_lock
)) {
1020 mutex_enter(&zvol_state_lock
);
1024 if (zv
->zv_open_count
> 0) {
1025 zv
->zv_open_count
--;
1026 if (zv
->zv_open_count
== 0)
1027 zvol_last_close(zv
);
1031 mutex_exit(&zvol_state_lock
);
1033 #ifndef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
1039 zvol_ioctl(struct block_device
*bdev
, fmode_t mode
,
1040 unsigned int cmd
, unsigned long arg
)
1042 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
1046 return (SET_ERROR(-ENXIO
));
1050 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
1053 error
= copy_to_user((void *)arg
, zv
->zv_name
, MAXNAMELEN
);
1062 return (SET_ERROR(error
));
1065 #ifdef CONFIG_COMPAT
1067 zvol_compat_ioctl(struct block_device
*bdev
, fmode_t mode
,
1068 unsigned cmd
, unsigned long arg
)
1070 return (zvol_ioctl(bdev
, mode
, cmd
, arg
));
1073 #define zvol_compat_ioctl NULL
1076 static int zvol_media_changed(struct gendisk
*disk
)
1078 zvol_state_t
*zv
= disk
->private_data
;
1080 return (zv
->zv_changed
);
1083 static int zvol_revalidate_disk(struct gendisk
*disk
)
1085 zvol_state_t
*zv
= disk
->private_data
;
1088 set_capacity(zv
->zv_disk
, zv
->zv_volsize
>> 9);
1094 * Provide a simple virtual geometry for legacy compatibility. For devices
1095 * smaller than 1 MiB a small head and sector count is used to allow very
1096 * tiny devices. For devices over 1 Mib a standard head and sector count
1097 * is used to keep the cylinders count reasonable.
1100 zvol_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
1102 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
1103 sector_t sectors
= get_capacity(zv
->zv_disk
);
1105 if (sectors
> 2048) {
1114 geo
->cylinders
= sectors
/ (geo
->heads
* geo
->sectors
);
1119 static struct kobject
*
1120 zvol_probe(dev_t dev
, int *part
, void *arg
)
1123 struct kobject
*kobj
;
1125 mutex_enter(&zvol_state_lock
);
1126 zv
= zvol_find_by_dev(dev
);
1127 kobj
= zv
? get_disk(zv
->zv_disk
) : NULL
;
1128 mutex_exit(&zvol_state_lock
);
1133 #ifdef HAVE_BDEV_BLOCK_DEVICE_OPERATIONS
1134 static struct block_device_operations zvol_ops
= {
1136 .release
= zvol_release
,
1137 .ioctl
= zvol_ioctl
,
1138 .compat_ioctl
= zvol_compat_ioctl
,
1139 .media_changed
= zvol_media_changed
,
1140 .revalidate_disk
= zvol_revalidate_disk
,
1141 .getgeo
= zvol_getgeo
,
1142 .owner
= THIS_MODULE
,
1145 #else /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1148 zvol_open_by_inode(struct inode
*inode
, struct file
*file
)
1150 return (zvol_open(inode
->i_bdev
, file
->f_mode
));
1154 zvol_release_by_inode(struct inode
*inode
, struct file
*file
)
1156 return (zvol_release(inode
->i_bdev
->bd_disk
, file
->f_mode
));
1160 zvol_ioctl_by_inode(struct inode
*inode
, struct file
*file
,
1161 unsigned int cmd
, unsigned long arg
)
1163 if (file
== NULL
|| inode
== NULL
)
1164 return (SET_ERROR(-EINVAL
));
1166 return (zvol_ioctl(inode
->i_bdev
, file
->f_mode
, cmd
, arg
));
1169 #ifdef CONFIG_COMPAT
1171 zvol_compat_ioctl_by_inode(struct file
*file
,
1172 unsigned int cmd
, unsigned long arg
)
1175 return (SET_ERROR(-EINVAL
));
1177 return (zvol_compat_ioctl(file
->f_dentry
->d_inode
->i_bdev
,
1178 file
->f_mode
, cmd
, arg
));
1181 #define zvol_compat_ioctl_by_inode NULL
1184 static struct block_device_operations zvol_ops
= {
1185 .open
= zvol_open_by_inode
,
1186 .release
= zvol_release_by_inode
,
1187 .ioctl
= zvol_ioctl_by_inode
,
1188 .compat_ioctl
= zvol_compat_ioctl_by_inode
,
1189 .media_changed
= zvol_media_changed
,
1190 .revalidate_disk
= zvol_revalidate_disk
,
1191 .getgeo
= zvol_getgeo
,
1192 .owner
= THIS_MODULE
,
1194 #endif /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1197 * Allocate memory for a new zvol_state_t and setup the required
1198 * request queue and generic disk structures for the block device.
1200 static zvol_state_t
*
1201 zvol_alloc(dev_t dev
, const char *name
)
1205 zv
= kmem_zalloc(sizeof (zvol_state_t
), KM_SLEEP
);
1207 spin_lock_init(&zv
->zv_lock
);
1208 list_link_init(&zv
->zv_next
);
1210 zv
->zv_queue
= blk_alloc_queue(GFP_ATOMIC
);
1211 if (zv
->zv_queue
== NULL
)
1214 blk_queue_make_request(zv
->zv_queue
, zvol_request
);
1216 #ifdef HAVE_BLK_QUEUE_FLUSH
1217 blk_queue_flush(zv
->zv_queue
, VDEV_REQ_FLUSH
| VDEV_REQ_FUA
);
1219 blk_queue_ordered(zv
->zv_queue
, QUEUE_ORDERED_DRAIN
, NULL
);
1220 #endif /* HAVE_BLK_QUEUE_FLUSH */
1222 zv
->zv_disk
= alloc_disk(ZVOL_MINORS
);
1223 if (zv
->zv_disk
== NULL
)
1226 zv
->zv_queue
->queuedata
= zv
;
1228 zv
->zv_open_count
= 0;
1229 strlcpy(zv
->zv_name
, name
, MAXNAMELEN
);
1231 mutex_init(&zv
->zv_znode
.z_range_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1232 avl_create(&zv
->zv_znode
.z_range_avl
, zfs_range_compare
,
1233 sizeof (rl_t
), offsetof(rl_t
, r_node
));
1234 zv
->zv_znode
.z_is_zvol
= TRUE
;
1236 zv
->zv_disk
->major
= zvol_major
;
1237 zv
->zv_disk
->first_minor
= (dev
& MINORMASK
);
1238 zv
->zv_disk
->fops
= &zvol_ops
;
1239 zv
->zv_disk
->private_data
= zv
;
1240 zv
->zv_disk
->queue
= zv
->zv_queue
;
1241 snprintf(zv
->zv_disk
->disk_name
, DISK_NAME_LEN
, "%s%d",
1242 ZVOL_DEV_NAME
, (dev
& MINORMASK
));
1247 blk_cleanup_queue(zv
->zv_queue
);
1249 kmem_free(zv
, sizeof (zvol_state_t
));
1255 * Cleanup then free a zvol_state_t which was created by zvol_alloc().
1258 zvol_free(zvol_state_t
*zv
)
1260 avl_destroy(&zv
->zv_znode
.z_range_avl
);
1261 mutex_destroy(&zv
->zv_znode
.z_range_lock
);
1263 del_gendisk(zv
->zv_disk
);
1264 blk_cleanup_queue(zv
->zv_queue
);
1265 put_disk(zv
->zv_disk
);
1267 kmem_free(zv
, sizeof (zvol_state_t
));
1271 __zvol_snapdev_hidden(const char *name
)
1278 parent
= kmem_alloc(MAXPATHLEN
, KM_SLEEP
);
1279 (void) strlcpy(parent
, name
, MAXPATHLEN
);
1281 if ((atp
= strrchr(parent
, '@')) != NULL
) {
1283 error
= dsl_prop_get_integer(parent
, "snapdev", &snapdev
, NULL
);
1284 if ((error
== 0) && (snapdev
== ZFS_SNAPDEV_HIDDEN
))
1285 error
= SET_ERROR(ENODEV
);
1288 kmem_free(parent
, MAXPATHLEN
);
1290 return (SET_ERROR(error
));
1294 __zvol_create_minor(const char *name
, boolean_t ignore_snapdev
)
1298 dmu_object_info_t
*doi
;
1304 ASSERT(MUTEX_HELD(&zvol_state_lock
));
1306 zv
= zvol_find_by_name(name
);
1308 error
= SET_ERROR(EEXIST
);
1312 if (ignore_snapdev
== B_FALSE
) {
1313 error
= __zvol_snapdev_hidden(name
);
1318 doi
= kmem_alloc(sizeof (dmu_object_info_t
), KM_SLEEP
);
1320 error
= dmu_objset_own(name
, DMU_OST_ZVOL
, B_TRUE
, zvol_tag
, &os
);
1324 error
= dmu_object_info(os
, ZVOL_OBJ
, doi
);
1326 goto out_dmu_objset_disown
;
1328 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
);
1330 goto out_dmu_objset_disown
;
1332 error
= zvol_find_minor(&minor
);
1334 goto out_dmu_objset_disown
;
1336 zv
= zvol_alloc(MKDEV(zvol_major
, minor
), name
);
1338 error
= SET_ERROR(EAGAIN
);
1339 goto out_dmu_objset_disown
;
1342 if (dmu_objset_is_snapshot(os
))
1343 zv
->zv_flags
|= ZVOL_RDONLY
;
1345 zv
->zv_volblocksize
= doi
->doi_data_block_size
;
1346 zv
->zv_volsize
= volsize
;
1349 set_capacity(zv
->zv_disk
, zv
->zv_volsize
>> 9);
1351 blk_queue_max_hw_sectors(zv
->zv_queue
, (DMU_MAX_ACCESS
/ 4) >> 9);
1352 blk_queue_max_segments(zv
->zv_queue
, UINT16_MAX
);
1353 blk_queue_max_segment_size(zv
->zv_queue
, UINT_MAX
);
1354 blk_queue_physical_block_size(zv
->zv_queue
, zv
->zv_volblocksize
);
1355 blk_queue_io_opt(zv
->zv_queue
, zv
->zv_volblocksize
);
1356 blk_queue_max_discard_sectors(zv
->zv_queue
,
1357 (zvol_max_discard_blocks
* zv
->zv_volblocksize
) >> 9);
1358 blk_queue_discard_granularity(zv
->zv_queue
, zv
->zv_volblocksize
);
1359 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
, zv
->zv_queue
);
1360 #ifdef QUEUE_FLAG_NONROT
1361 queue_flag_set_unlocked(QUEUE_FLAG_NONROT
, zv
->zv_queue
);
1363 #ifdef QUEUE_FLAG_ADD_RANDOM
1364 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM
, zv
->zv_queue
);
1367 if (spa_writeable(dmu_objset_spa(os
))) {
1368 if (zil_replay_disable
)
1369 zil_destroy(dmu_objset_zil(os
), B_FALSE
);
1371 zil_replay(os
, zv
, zvol_replay_vector
);
1375 * When udev detects the addition of the device it will immediately
1376 * invoke blkid(8) to determine the type of content on the device.
1377 * Prefetching the blocks commonly scanned by blkid(8) will speed
1380 len
= MIN(MAX(zvol_prefetch_bytes
, 0), SPA_MAXBLOCKSIZE
);
1382 dmu_prefetch(os
, ZVOL_OBJ
, 0, len
);
1383 dmu_prefetch(os
, ZVOL_OBJ
, volsize
- len
, len
);
1386 zv
->zv_objset
= NULL
;
1387 out_dmu_objset_disown
:
1388 dmu_objset_disown(os
, zvol_tag
);
1390 kmem_free(doi
, sizeof (dmu_object_info_t
));
1395 add_disk(zv
->zv_disk
);
1398 return (SET_ERROR(error
));
1402 * Create a block device minor node and setup the linkage between it
1403 * and the specified volume. Once this function returns the block
1404 * device is live and ready for use.
1407 zvol_create_minor(const char *name
)
1411 mutex_enter(&zvol_state_lock
);
1412 error
= __zvol_create_minor(name
, B_FALSE
);
1413 mutex_exit(&zvol_state_lock
);
1415 return (SET_ERROR(error
));
1419 __zvol_remove_minor(const char *name
)
1423 ASSERT(MUTEX_HELD(&zvol_state_lock
));
1425 zv
= zvol_find_by_name(name
);
1427 return (SET_ERROR(ENXIO
));
1429 if (zv
->zv_open_count
> 0)
1430 return (SET_ERROR(EBUSY
));
1439 * Remove a block device minor node for the specified volume.
1442 zvol_remove_minor(const char *name
)
1446 mutex_enter(&zvol_state_lock
);
1447 error
= __zvol_remove_minor(name
);
1448 mutex_exit(&zvol_state_lock
);
1450 return (SET_ERROR(error
));
1454 * Rename a block device minor mode for the specified volume.
1457 __zvol_rename_minor(zvol_state_t
*zv
, const char *newname
)
1459 int readonly
= get_disk_ro(zv
->zv_disk
);
1461 ASSERT(MUTEX_HELD(&zvol_state_lock
));
1463 strlcpy(zv
->zv_name
, newname
, sizeof (zv
->zv_name
));
1466 * The block device's read-only state is briefly changed causing
1467 * a KOBJ_CHANGE uevent to be issued. This ensures udev detects
1468 * the name change and fixes the symlinks. This does not change
1469 * ZVOL_RDONLY in zv->zv_flags so the actual read-only state never
1470 * changes. This would normally be done using kobject_uevent() but
1471 * that is a GPL-only symbol which is why we need this workaround.
1473 set_disk_ro(zv
->zv_disk
, !readonly
);
1474 set_disk_ro(zv
->zv_disk
, readonly
);
1478 zvol_create_minors_cb(const char *dsname
, void *arg
)
1480 (void) zvol_create_minor(dsname
);
1486 * Create minors for specified dataset including children and snapshots.
1489 zvol_create_minors(const char *name
)
1493 if (!zvol_inhibit_dev
)
1494 error
= dmu_objset_find((char *)name
, zvol_create_minors_cb
,
1495 NULL
, DS_FIND_CHILDREN
| DS_FIND_SNAPSHOTS
);
1497 return (SET_ERROR(error
));
1501 * Remove minors for specified dataset including children and snapshots.
1504 zvol_remove_minors(const char *name
)
1506 zvol_state_t
*zv
, *zv_next
;
1507 int namelen
= ((name
) ? strlen(name
) : 0);
1509 if (zvol_inhibit_dev
)
1512 mutex_enter(&zvol_state_lock
);
1514 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
; zv
= zv_next
) {
1515 zv_next
= list_next(&zvol_state_list
, zv
);
1517 if (name
== NULL
|| strcmp(zv
->zv_name
, name
) == 0 ||
1518 (strncmp(zv
->zv_name
, name
, namelen
) == 0 &&
1519 zv
->zv_name
[namelen
] == '/')) {
1525 mutex_exit(&zvol_state_lock
);
1529 * Rename minors for specified dataset including children and snapshots.
1532 zvol_rename_minors(const char *oldname
, const char *newname
)
1534 zvol_state_t
*zv
, *zv_next
;
1535 int oldnamelen
, newnamelen
;
1538 if (zvol_inhibit_dev
)
1541 oldnamelen
= strlen(oldname
);
1542 newnamelen
= strlen(newname
);
1543 name
= kmem_alloc(MAXNAMELEN
, KM_SLEEP
);
1545 mutex_enter(&zvol_state_lock
);
1547 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
; zv
= zv_next
) {
1548 zv_next
= list_next(&zvol_state_list
, zv
);
1550 if (strcmp(zv
->zv_name
, oldname
) == 0) {
1551 __zvol_rename_minor(zv
, newname
);
1552 } else if (strncmp(zv
->zv_name
, oldname
, oldnamelen
) == 0 &&
1553 (zv
->zv_name
[oldnamelen
] == '/' ||
1554 zv
->zv_name
[oldnamelen
] == '@')) {
1555 snprintf(name
, MAXNAMELEN
, "%s%c%s", newname
,
1556 zv
->zv_name
[oldnamelen
],
1557 zv
->zv_name
+ oldnamelen
+ 1);
1558 __zvol_rename_minor(zv
, name
);
1562 mutex_exit(&zvol_state_lock
);
1564 kmem_free(name
, MAXNAMELEN
);
1568 snapdev_snapshot_changed_cb(const char *dsname
, void *arg
) {
1569 uint64_t snapdev
= *(uint64_t *) arg
;
1571 if (strchr(dsname
, '@') == NULL
)
1575 case ZFS_SNAPDEV_VISIBLE
:
1576 mutex_enter(&zvol_state_lock
);
1577 (void) __zvol_create_minor(dsname
, B_TRUE
);
1578 mutex_exit(&zvol_state_lock
);
1580 case ZFS_SNAPDEV_HIDDEN
:
1581 (void) zvol_remove_minor(dsname
);
1589 zvol_set_snapdev(const char *dsname
, uint64_t snapdev
) {
1590 (void) dmu_objset_find((char *) dsname
, snapdev_snapshot_changed_cb
,
1591 &snapdev
, DS_FIND_SNAPSHOTS
| DS_FIND_CHILDREN
);
1592 /* caller should continue to modify snapdev property */
1601 list_create(&zvol_state_list
, sizeof (zvol_state_t
),
1602 offsetof(zvol_state_t
, zv_next
));
1604 mutex_init(&zvol_state_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1606 error
= register_blkdev(zvol_major
, ZVOL_DRIVER
);
1608 printk(KERN_INFO
"ZFS: register_blkdev() failed %d\n", error
);
1612 blk_register_region(MKDEV(zvol_major
, 0), 1UL << MINORBITS
,
1613 THIS_MODULE
, zvol_probe
, NULL
, NULL
);
1618 mutex_destroy(&zvol_state_lock
);
1619 list_destroy(&zvol_state_list
);
1621 return (SET_ERROR(error
));
1627 zvol_remove_minors(NULL
);
1628 blk_unregister_region(MKDEV(zvol_major
, 0), 1UL << MINORBITS
);
1629 unregister_blkdev(zvol_major
, ZVOL_DRIVER
);
1630 mutex_destroy(&zvol_state_lock
);
1631 list_destroy(&zvol_state_list
);
1634 module_param(zvol_inhibit_dev
, uint
, 0644);
1635 MODULE_PARM_DESC(zvol_inhibit_dev
, "Do not create zvol device nodes");
1637 module_param(zvol_major
, uint
, 0444);
1638 MODULE_PARM_DESC(zvol_major
, "Major number for zvol device");
1640 module_param(zvol_max_discard_blocks
, ulong
, 0444);
1641 MODULE_PARM_DESC(zvol_max_discard_blocks
, "Max number of blocks to discard");
1643 module_param(zvol_prefetch_bytes
, uint
, 0644);
1644 MODULE_PARM_DESC(zvol_prefetch_bytes
, "Prefetch N bytes at zvol start+end");