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.
38 #include <sys/dmu_traverse.h>
39 #include <sys/dsl_dataset.h>
40 #include <sys/dsl_prop.h>
42 #include <sys/zil_impl.h>
44 #include <sys/zfs_rlock.h>
45 #include <sys/zfs_znode.h>
47 #include <linux/blkdev_compat.h>
49 unsigned int zvol_inhibit_dev
= 0;
50 unsigned int zvol_major
= ZVOL_MAJOR
;
51 unsigned int zvol_threads
= 32;
52 unsigned long zvol_max_discard_blocks
= 16384;
54 static taskq_t
*zvol_taskq
;
55 static kmutex_t zvol_state_lock
;
56 static list_t zvol_state_list
;
57 static char *zvol_tag
= "zvol_tag";
60 * The in-core state of each volume.
62 typedef struct zvol_state
{
63 char zv_name
[MAXNAMELEN
]; /* name */
64 uint64_t zv_volsize
; /* advertised space */
65 uint64_t zv_volblocksize
;/* volume block size */
66 objset_t
*zv_objset
; /* objset handle */
67 uint32_t zv_flags
; /* ZVOL_* flags */
68 uint32_t zv_open_count
; /* open counts */
69 uint32_t zv_changed
; /* disk changed */
70 zilog_t
*zv_zilog
; /* ZIL handle */
71 znode_t zv_znode
; /* for range locking */
72 dmu_buf_t
*zv_dbuf
; /* bonus handle */
73 dev_t zv_dev
; /* device id */
74 struct gendisk
*zv_disk
; /* generic disk */
75 struct request_queue
*zv_queue
; /* request queue */
76 spinlock_t zv_lock
; /* request queue lock */
77 list_node_t zv_next
; /* next zvol_state_t linkage */
80 #define ZVOL_RDONLY 0x1
83 * Find the next available range of ZVOL_MINORS minor numbers. The
84 * zvol_state_list is kept in ascending minor order so we simply need
85 * to scan the list for the first gap in the sequence. This allows us
86 * to recycle minor number as devices are created and removed.
89 zvol_find_minor(unsigned *minor
)
94 ASSERT(MUTEX_HELD(&zvol_state_lock
));
95 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
96 zv
= list_next(&zvol_state_list
, zv
), *minor
+= ZVOL_MINORS
) {
97 if (MINOR(zv
->zv_dev
) != MINOR(*minor
))
101 /* All minors are in use */
102 if (*minor
>= (1 << MINORBITS
))
109 * Find a zvol_state_t given the full major+minor dev_t.
111 static zvol_state_t
*
112 zvol_find_by_dev(dev_t dev
)
116 ASSERT(MUTEX_HELD(&zvol_state_lock
));
117 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
118 zv
= list_next(&zvol_state_list
, zv
)) {
119 if (zv
->zv_dev
== dev
)
127 * Find a zvol_state_t given the name provided at zvol_alloc() time.
129 static zvol_state_t
*
130 zvol_find_by_name(const char *name
)
134 ASSERT(MUTEX_HELD(&zvol_state_lock
));
135 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
136 zv
= list_next(&zvol_state_list
, zv
)) {
137 if (!strncmp(zv
->zv_name
, name
, MAXNAMELEN
))
145 * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation.
148 zvol_create_cb(objset_t
*os
, void *arg
, cred_t
*cr
, dmu_tx_t
*tx
)
150 zfs_creat_t
*zct
= arg
;
151 nvlist_t
*nvprops
= zct
->zct_props
;
153 uint64_t volblocksize
, volsize
;
155 VERIFY(nvlist_lookup_uint64(nvprops
,
156 zfs_prop_to_name(ZFS_PROP_VOLSIZE
), &volsize
) == 0);
157 if (nvlist_lookup_uint64(nvprops
,
158 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE
), &volblocksize
) != 0)
159 volblocksize
= zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE
);
162 * These properties must be removed from the list so the generic
163 * property setting step won't apply to them.
165 VERIFY(nvlist_remove_all(nvprops
,
166 zfs_prop_to_name(ZFS_PROP_VOLSIZE
)) == 0);
167 (void) nvlist_remove_all(nvprops
,
168 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE
));
170 error
= dmu_object_claim(os
, ZVOL_OBJ
, DMU_OT_ZVOL
, volblocksize
,
174 error
= zap_create_claim(os
, ZVOL_ZAP_OBJ
, DMU_OT_ZVOL_PROP
,
178 error
= zap_update(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
, tx
);
183 * ZFS_IOC_OBJSET_STATS entry point.
186 zvol_get_stats(objset_t
*os
, nvlist_t
*nv
)
189 dmu_object_info_t
*doi
;
192 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &val
);
196 dsl_prop_nvlist_add_uint64(nv
, ZFS_PROP_VOLSIZE
, val
);
197 doi
= kmem_alloc(sizeof(dmu_object_info_t
), KM_SLEEP
);
198 error
= dmu_object_info(os
, ZVOL_OBJ
, doi
);
201 dsl_prop_nvlist_add_uint64(nv
, ZFS_PROP_VOLBLOCKSIZE
,
202 doi
->doi_data_block_size
);
205 kmem_free(doi
, sizeof(dmu_object_info_t
));
211 * Sanity check volume size.
214 zvol_check_volsize(uint64_t volsize
, uint64_t blocksize
)
219 if (volsize
% blocksize
!= 0)
223 if (volsize
- 1 > MAXOFFSET_T
)
230 * Ensure the zap is flushed then inform the VFS of the capacity change.
233 zvol_update_volsize(zvol_state_t
*zv
, uint64_t volsize
, objset_t
*os
)
235 struct block_device
*bdev
;
239 ASSERT(MUTEX_HELD(&zvol_state_lock
));
241 tx
= dmu_tx_create(os
);
242 dmu_tx_hold_zap(tx
, ZVOL_ZAP_OBJ
, TRUE
, NULL
);
243 error
= dmu_tx_assign(tx
, TXG_WAIT
);
249 error
= zap_update(os
, ZVOL_ZAP_OBJ
, "size", 8, 1,
256 error
= dmu_free_long_range(os
,
257 ZVOL_OBJ
, volsize
, DMU_OBJECT_END
);
261 bdev
= bdget_disk(zv
->zv_disk
, 0);
266 * Added check_disk_size_change() helper function.
268 #ifdef HAVE_CHECK_DISK_SIZE_CHANGE
269 set_capacity(zv
->zv_disk
, volsize
>> 9);
270 zv
->zv_volsize
= volsize
;
271 check_disk_size_change(zv
->zv_disk
, bdev
);
273 zv
->zv_volsize
= volsize
;
275 (void) check_disk_change(bdev
);
276 #endif /* HAVE_CHECK_DISK_SIZE_CHANGE */
284 * Set ZFS_PROP_VOLSIZE set entry point.
287 zvol_set_volsize(const char *name
, uint64_t volsize
)
290 dmu_object_info_t
*doi
;
295 mutex_enter(&zvol_state_lock
);
297 zv
= zvol_find_by_name(name
);
303 doi
= kmem_alloc(sizeof(dmu_object_info_t
), KM_SLEEP
);
305 error
= dmu_objset_hold(name
, FTAG
, &os
);
309 if ((error
= dmu_object_info(os
, ZVOL_OBJ
, doi
)) != 0 ||
310 (error
= zvol_check_volsize(volsize
,doi
->doi_data_block_size
)) != 0)
313 VERIFY(dsl_prop_get_integer(name
, "readonly", &readonly
, NULL
) == 0);
319 if (get_disk_ro(zv
->zv_disk
) || (zv
->zv_flags
& ZVOL_RDONLY
)) {
324 error
= zvol_update_volsize(zv
, volsize
, os
);
326 kmem_free(doi
, sizeof(dmu_object_info_t
));
329 dmu_objset_rele(os
, FTAG
);
331 mutex_exit(&zvol_state_lock
);
337 * Sanity check volume block size.
340 zvol_check_volblocksize(uint64_t volblocksize
)
342 if (volblocksize
< SPA_MINBLOCKSIZE
||
343 volblocksize
> SPA_MAXBLOCKSIZE
||
351 * Set ZFS_PROP_VOLBLOCKSIZE set entry point.
354 zvol_set_volblocksize(const char *name
, uint64_t volblocksize
)
360 mutex_enter(&zvol_state_lock
);
362 zv
= zvol_find_by_name(name
);
368 if (get_disk_ro(zv
->zv_disk
) || (zv
->zv_flags
& ZVOL_RDONLY
)) {
373 tx
= dmu_tx_create(zv
->zv_objset
);
374 dmu_tx_hold_bonus(tx
, ZVOL_OBJ
);
375 error
= dmu_tx_assign(tx
, TXG_WAIT
);
379 error
= dmu_object_set_blocksize(zv
->zv_objset
, ZVOL_OBJ
,
380 volblocksize
, 0, tx
);
381 if (error
== ENOTSUP
)
385 zv
->zv_volblocksize
= volblocksize
;
388 mutex_exit(&zvol_state_lock
);
394 * Replay a TX_WRITE ZIL transaction that didn't get committed
395 * after a system failure
398 zvol_replay_write(zvol_state_t
*zv
, lr_write_t
*lr
, boolean_t byteswap
)
400 objset_t
*os
= zv
->zv_objset
;
401 char *data
= (char *)(lr
+ 1); /* data follows lr_write_t */
402 uint64_t off
= lr
->lr_offset
;
403 uint64_t len
= lr
->lr_length
;
408 byteswap_uint64_array(lr
, sizeof (*lr
));
410 tx
= dmu_tx_create(os
);
411 dmu_tx_hold_write(tx
, ZVOL_OBJ
, off
, len
);
412 error
= dmu_tx_assign(tx
, TXG_WAIT
);
416 dmu_write(os
, ZVOL_OBJ
, off
, len
, data
, tx
);
424 zvol_replay_err(zvol_state_t
*zv
, lr_t
*lr
, boolean_t byteswap
)
430 * Callback vectors for replaying records.
431 * Only TX_WRITE is needed for zvol.
433 zil_replay_func_t
*zvol_replay_vector
[TX_MAX_TYPE
] = {
434 (zil_replay_func_t
*)zvol_replay_err
, /* no such transaction type */
435 (zil_replay_func_t
*)zvol_replay_err
, /* TX_CREATE */
436 (zil_replay_func_t
*)zvol_replay_err
, /* TX_MKDIR */
437 (zil_replay_func_t
*)zvol_replay_err
, /* TX_MKXATTR */
438 (zil_replay_func_t
*)zvol_replay_err
, /* TX_SYMLINK */
439 (zil_replay_func_t
*)zvol_replay_err
, /* TX_REMOVE */
440 (zil_replay_func_t
*)zvol_replay_err
, /* TX_RMDIR */
441 (zil_replay_func_t
*)zvol_replay_err
, /* TX_LINK */
442 (zil_replay_func_t
*)zvol_replay_err
, /* TX_RENAME */
443 (zil_replay_func_t
*)zvol_replay_write
, /* TX_WRITE */
444 (zil_replay_func_t
*)zvol_replay_err
, /* TX_TRUNCATE */
445 (zil_replay_func_t
*)zvol_replay_err
, /* TX_SETATTR */
446 (zil_replay_func_t
*)zvol_replay_err
, /* TX_ACL */
450 * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
452 * We store data in the log buffers if it's small enough.
453 * Otherwise we will later flush the data out via dmu_sync().
455 ssize_t zvol_immediate_write_sz
= 32768;
458 zvol_log_write(zvol_state_t
*zv
, dmu_tx_t
*tx
,
459 uint64_t offset
, uint64_t size
, int sync
)
461 uint32_t blocksize
= zv
->zv_volblocksize
;
462 zilog_t
*zilog
= zv
->zv_zilog
;
464 ssize_t immediate_write_sz
;
466 if (zil_replaying(zilog
, tx
))
469 immediate_write_sz
= (zilog
->zl_logbias
== ZFS_LOGBIAS_THROUGHPUT
)
470 ? 0 : zvol_immediate_write_sz
;
471 slogging
= spa_has_slogs(zilog
->zl_spa
) &&
472 (zilog
->zl_logbias
== ZFS_LOGBIAS_LATENCY
);
478 itx_wr_state_t write_state
;
481 * Unlike zfs_log_write() we can be called with
482 * up to DMU_MAX_ACCESS/2 (5MB) writes.
484 if (blocksize
> immediate_write_sz
&& !slogging
&&
485 size
>= blocksize
&& offset
% blocksize
== 0) {
486 write_state
= WR_INDIRECT
; /* uses dmu_sync */
489 write_state
= WR_COPIED
;
490 len
= MIN(ZIL_MAX_LOG_DATA
, size
);
492 write_state
= WR_NEED_COPY
;
493 len
= MIN(ZIL_MAX_LOG_DATA
, size
);
496 itx
= zil_itx_create(TX_WRITE
, sizeof (*lr
) +
497 (write_state
== WR_COPIED
? len
: 0));
498 lr
= (lr_write_t
*)&itx
->itx_lr
;
499 if (write_state
== WR_COPIED
&& dmu_read(zv
->zv_objset
,
500 ZVOL_OBJ
, offset
, len
, lr
+1, DMU_READ_NO_PREFETCH
) != 0) {
501 zil_itx_destroy(itx
);
502 itx
= zil_itx_create(TX_WRITE
, sizeof (*lr
));
503 lr
= (lr_write_t
*)&itx
->itx_lr
;
504 write_state
= WR_NEED_COPY
;
507 itx
->itx_wr_state
= write_state
;
508 if (write_state
== WR_NEED_COPY
)
510 lr
->lr_foid
= ZVOL_OBJ
;
511 lr
->lr_offset
= offset
;
514 BP_ZERO(&lr
->lr_blkptr
);
516 itx
->itx_private
= zv
;
517 itx
->itx_sync
= sync
;
519 (void) zil_itx_assign(zilog
, itx
, tx
);
527 * Common write path running under the zvol taskq context. This function
528 * is responsible for copying the request structure data in to the DMU and
529 * signaling the request queue with the result of the copy.
532 zvol_write(void *arg
)
534 struct request
*req
= (struct request
*)arg
;
535 struct request_queue
*q
= req
->q
;
536 zvol_state_t
*zv
= q
->queuedata
;
537 uint64_t offset
= blk_rq_pos(req
) << 9;
538 uint64_t size
= blk_rq_bytes(req
);
544 * Annotate this call path with a flag that indicates that it is
545 * unsafe to use KM_SLEEP during memory allocations due to the
546 * potential for a deadlock. KM_PUSHPAGE should be used instead.
548 ASSERT(!(current
->flags
& PF_NOFS
));
549 current
->flags
|= PF_NOFS
;
551 if (req
->cmd_flags
& VDEV_REQ_FLUSH
)
552 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
555 * Some requests are just for flush and nothing else.
558 blk_end_request(req
, 0, size
);
562 rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_WRITER
);
564 tx
= dmu_tx_create(zv
->zv_objset
);
565 dmu_tx_hold_write(tx
, ZVOL_OBJ
, offset
, size
);
567 /* This will only fail for ENOSPC */
568 error
= dmu_tx_assign(tx
, TXG_WAIT
);
571 zfs_range_unlock(rl
);
572 blk_end_request(req
, -error
, size
);
576 error
= dmu_write_req(zv
->zv_objset
, ZVOL_OBJ
, req
, tx
);
578 zvol_log_write(zv
, tx
, offset
, size
,
579 req
->cmd_flags
& VDEV_REQ_FUA
);
582 zfs_range_unlock(rl
);
584 if ((req
->cmd_flags
& VDEV_REQ_FUA
) ||
585 zv
->zv_objset
->os_sync
== ZFS_SYNC_ALWAYS
)
586 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
588 blk_end_request(req
, -error
, size
);
590 current
->flags
&= ~PF_NOFS
;
593 #ifdef HAVE_BLK_QUEUE_DISCARD
595 zvol_discard(void *arg
)
597 struct request
*req
= (struct request
*)arg
;
598 struct request_queue
*q
= req
->q
;
599 zvol_state_t
*zv
= q
->queuedata
;
600 uint64_t offset
= blk_rq_pos(req
) << 9;
601 uint64_t size
= blk_rq_bytes(req
);
606 * Annotate this call path with a flag that indicates that it is
607 * unsafe to use KM_SLEEP during memory allocations due to the
608 * potential for a deadlock. KM_PUSHPAGE should be used instead.
610 ASSERT(!(current
->flags
& PF_NOFS
));
611 current
->flags
|= PF_NOFS
;
613 if (offset
+ size
> zv
->zv_volsize
) {
614 blk_end_request(req
, -EIO
, size
);
619 blk_end_request(req
, 0, size
);
623 rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_WRITER
);
625 error
= dmu_free_long_range(zv
->zv_objset
, ZVOL_OBJ
, offset
, size
);
628 * TODO: maybe we should add the operation to the log.
631 zfs_range_unlock(rl
);
633 blk_end_request(req
, -error
, size
);
635 current
->flags
&= ~PF_NOFS
;
637 #endif /* HAVE_BLK_QUEUE_DISCARD */
640 * Common read path running under the zvol taskq context. This function
641 * is responsible for copying the requested data out of the DMU and in to
642 * a linux request structure. It then must signal the request queue with
643 * an error code describing the result of the copy.
648 struct request
*req
= (struct request
*)arg
;
649 struct request_queue
*q
= req
->q
;
650 zvol_state_t
*zv
= q
->queuedata
;
651 uint64_t offset
= blk_rq_pos(req
) << 9;
652 uint64_t size
= blk_rq_bytes(req
);
657 blk_end_request(req
, 0, size
);
661 rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_READER
);
663 error
= dmu_read_req(zv
->zv_objset
, ZVOL_OBJ
, req
);
665 zfs_range_unlock(rl
);
667 /* convert checksum errors into IO errors */
671 blk_end_request(req
, -error
, size
);
675 * Request will be added back to the request queue and retried if
676 * it cannot be immediately dispatched to the taskq for handling
679 zvol_dispatch(task_func_t func
, struct request
*req
)
681 if (!taskq_dispatch(zvol_taskq
, func
, (void *)req
, TQ_NOSLEEP
))
682 blk_requeue_request(req
->q
, req
);
686 * Common request path. Rather than registering a custom make_request()
687 * function we use the generic Linux version. This is done because it allows
688 * us to easily merge read requests which would otherwise we performed
689 * synchronously by the DMU. This is less critical in write case where the
690 * DMU will perform the correct merging within a transaction group. Using
691 * the generic make_request() also let's use leverage the fact that the
692 * elevator with ensure correct ordering in regards to barrior IOs. On
693 * the downside it means that in the write case we end up doing request
694 * merging twice once in the elevator and once in the DMU.
696 * The request handler is called under a spin lock so all the real work
697 * is handed off to be done in the context of the zvol taskq. This function
698 * simply performs basic request sanity checking and hands off the request.
701 zvol_request(struct request_queue
*q
)
703 zvol_state_t
*zv
= q
->queuedata
;
707 while ((req
= blk_fetch_request(q
)) != NULL
) {
708 size
= blk_rq_bytes(req
);
710 if (size
!= 0 && blk_rq_pos(req
) + blk_rq_sectors(req
) >
711 get_capacity(zv
->zv_disk
)) {
713 "%s: bad access: block=%llu, count=%lu\n",
714 req
->rq_disk
->disk_name
,
715 (long long unsigned)blk_rq_pos(req
),
716 (long unsigned)blk_rq_sectors(req
));
717 __blk_end_request(req
, -EIO
, size
);
721 if (!blk_fs_request(req
)) {
722 printk(KERN_INFO
"%s: non-fs cmd\n",
723 req
->rq_disk
->disk_name
);
724 __blk_end_request(req
, -EIO
, size
);
728 switch (rq_data_dir(req
)) {
730 zvol_dispatch(zvol_read
, req
);
733 if (unlikely(get_disk_ro(zv
->zv_disk
)) ||
734 unlikely(zv
->zv_flags
& ZVOL_RDONLY
)) {
735 __blk_end_request(req
, -EROFS
, size
);
739 #ifdef HAVE_BLK_QUEUE_DISCARD
740 if (req
->cmd_flags
& VDEV_REQ_DISCARD
) {
741 zvol_dispatch(zvol_discard
, req
);
744 #endif /* HAVE_BLK_QUEUE_DISCARD */
746 zvol_dispatch(zvol_write
, req
);
749 printk(KERN_INFO
"%s: unknown cmd: %d\n",
750 req
->rq_disk
->disk_name
, (int)rq_data_dir(req
));
751 __blk_end_request(req
, -EIO
, size
);
758 zvol_get_done(zgd_t
*zgd
, int error
)
761 dmu_buf_rele(zgd
->zgd_db
, zgd
);
763 zfs_range_unlock(zgd
->zgd_rl
);
765 if (error
== 0 && zgd
->zgd_bp
)
766 zil_add_block(zgd
->zgd_zilog
, zgd
->zgd_bp
);
768 kmem_free(zgd
, sizeof (zgd_t
));
772 * Get data to generate a TX_WRITE intent log record.
775 zvol_get_data(void *arg
, lr_write_t
*lr
, char *buf
, zio_t
*zio
)
777 zvol_state_t
*zv
= arg
;
778 objset_t
*os
= zv
->zv_objset
;
779 uint64_t offset
= lr
->lr_offset
;
780 uint64_t size
= lr
->lr_length
;
788 zgd
= (zgd_t
*)kmem_zalloc(sizeof (zgd_t
), KM_PUSHPAGE
);
789 zgd
->zgd_zilog
= zv
->zv_zilog
;
790 zgd
->zgd_rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_READER
);
793 * Write records come in two flavors: immediate and indirect.
794 * For small writes it's cheaper to store the data with the
795 * log record (immediate); for large writes it's cheaper to
796 * sync the data and get a pointer to it (indirect) so that
797 * we don't have to write the data twice.
799 if (buf
!= NULL
) { /* immediate write */
800 error
= dmu_read(os
, ZVOL_OBJ
, offset
, size
, buf
,
801 DMU_READ_NO_PREFETCH
);
803 size
= zv
->zv_volblocksize
;
804 offset
= P2ALIGN_TYPED(offset
, size
, uint64_t);
805 error
= dmu_buf_hold(os
, ZVOL_OBJ
, offset
, zgd
, &db
,
806 DMU_READ_NO_PREFETCH
);
809 zgd
->zgd_bp
= &lr
->lr_blkptr
;
812 ASSERT(db
->db_offset
== offset
);
813 ASSERT(db
->db_size
== size
);
815 error
= dmu_sync(zio
, lr
->lr_common
.lrc_txg
,
823 zvol_get_done(zgd
, error
);
829 * The zvol_state_t's are inserted in increasing MINOR(dev_t) order.
832 zvol_insert(zvol_state_t
*zv_insert
)
834 zvol_state_t
*zv
= NULL
;
836 ASSERT(MUTEX_HELD(&zvol_state_lock
));
837 ASSERT3U(MINOR(zv_insert
->zv_dev
) & ZVOL_MINOR_MASK
, ==, 0);
838 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
839 zv
= list_next(&zvol_state_list
, zv
)) {
840 if (MINOR(zv
->zv_dev
) > MINOR(zv_insert
->zv_dev
))
844 list_insert_before(&zvol_state_list
, zv
, zv_insert
);
848 * Simply remove the zvol from to list of zvols.
851 zvol_remove(zvol_state_t
*zv_remove
)
853 ASSERT(MUTEX_HELD(&zvol_state_lock
));
854 list_remove(&zvol_state_list
, zv_remove
);
858 zvol_first_open(zvol_state_t
*zv
)
865 /* lie and say we're read-only */
866 error
= dmu_objset_own(zv
->zv_name
, DMU_OST_ZVOL
, 1, zvol_tag
, &os
);
870 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
);
872 dmu_objset_disown(os
, zvol_tag
);
877 error
= dmu_bonus_hold(os
, ZVOL_OBJ
, zvol_tag
, &zv
->zv_dbuf
);
879 dmu_objset_disown(os
, zvol_tag
);
883 set_capacity(zv
->zv_disk
, volsize
>> 9);
884 zv
->zv_volsize
= volsize
;
885 zv
->zv_zilog
= zil_open(os
, zvol_get_data
);
887 VERIFY(dsl_prop_get_integer(zv
->zv_name
, "readonly", &ro
, NULL
) == 0);
888 if (ro
|| dmu_objset_is_snapshot(os
)) {
889 set_disk_ro(zv
->zv_disk
, 1);
890 zv
->zv_flags
|= ZVOL_RDONLY
;
892 set_disk_ro(zv
->zv_disk
, 0);
893 zv
->zv_flags
&= ~ZVOL_RDONLY
;
900 zvol_last_close(zvol_state_t
*zv
)
902 zil_close(zv
->zv_zilog
);
904 dmu_buf_rele(zv
->zv_dbuf
, zvol_tag
);
906 dmu_objset_disown(zv
->zv_objset
, zvol_tag
);
907 zv
->zv_objset
= NULL
;
911 zvol_open(struct block_device
*bdev
, fmode_t flag
)
913 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
914 int error
= 0, drop_mutex
= 0;
917 * If the caller is already holding the mutex do not take it
918 * again, this will happen as part of zvol_create_minor().
919 * Once add_disk() is called the device is live and the kernel
920 * will attempt to open it to read the partition information.
922 if (!mutex_owned(&zvol_state_lock
)) {
923 mutex_enter(&zvol_state_lock
);
927 ASSERT3P(zv
, !=, NULL
);
929 if (zv
->zv_open_count
== 0) {
930 error
= zvol_first_open(zv
);
935 if ((flag
& FMODE_WRITE
) &&
936 (get_disk_ro(zv
->zv_disk
) || (zv
->zv_flags
& ZVOL_RDONLY
))) {
944 if (zv
->zv_open_count
== 0)
949 mutex_exit(&zvol_state_lock
);
951 check_disk_change(bdev
);
957 zvol_release(struct gendisk
*disk
, fmode_t mode
)
959 zvol_state_t
*zv
= disk
->private_data
;
962 if (!mutex_owned(&zvol_state_lock
)) {
963 mutex_enter(&zvol_state_lock
);
967 ASSERT3P(zv
, !=, NULL
);
968 ASSERT3U(zv
->zv_open_count
, >, 0);
970 if (zv
->zv_open_count
== 0)
974 mutex_exit(&zvol_state_lock
);
980 zvol_ioctl(struct block_device
*bdev
, fmode_t mode
,
981 unsigned int cmd
, unsigned long arg
)
983 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
991 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
994 error
= copy_to_user((void *)arg
, zv
->zv_name
, MAXNAMELEN
);
1006 #ifdef CONFIG_COMPAT
1008 zvol_compat_ioctl(struct block_device
*bdev
, fmode_t mode
,
1009 unsigned cmd
, unsigned long arg
)
1011 return zvol_ioctl(bdev
, mode
, cmd
, arg
);
1014 #define zvol_compat_ioctl NULL
1017 static int zvol_media_changed(struct gendisk
*disk
)
1019 zvol_state_t
*zv
= disk
->private_data
;
1021 return zv
->zv_changed
;
1024 static int zvol_revalidate_disk(struct gendisk
*disk
)
1026 zvol_state_t
*zv
= disk
->private_data
;
1029 set_capacity(zv
->zv_disk
, zv
->zv_volsize
>> 9);
1035 * Provide a simple virtual geometry for legacy compatibility. For devices
1036 * smaller than 1 MiB a small head and sector count is used to allow very
1037 * tiny devices. For devices over 1 Mib a standard head and sector count
1038 * is used to keep the cylinders count reasonable.
1041 zvol_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
1043 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
1044 sector_t sectors
= get_capacity(zv
->zv_disk
);
1046 if (sectors
> 2048) {
1055 geo
->cylinders
= sectors
/ (geo
->heads
* geo
->sectors
);
1060 static struct kobject
*
1061 zvol_probe(dev_t dev
, int *part
, void *arg
)
1064 struct kobject
*kobj
;
1066 mutex_enter(&zvol_state_lock
);
1067 zv
= zvol_find_by_dev(dev
);
1068 kobj
= zv
? get_disk(zv
->zv_disk
) : ERR_PTR(-ENOENT
);
1069 mutex_exit(&zvol_state_lock
);
1074 #ifdef HAVE_BDEV_BLOCK_DEVICE_OPERATIONS
1075 static struct block_device_operations zvol_ops
= {
1077 .release
= zvol_release
,
1078 .ioctl
= zvol_ioctl
,
1079 .compat_ioctl
= zvol_compat_ioctl
,
1080 .media_changed
= zvol_media_changed
,
1081 .revalidate_disk
= zvol_revalidate_disk
,
1082 .getgeo
= zvol_getgeo
,
1083 .owner
= THIS_MODULE
,
1086 #else /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1089 zvol_open_by_inode(struct inode
*inode
, struct file
*file
)
1091 return zvol_open(inode
->i_bdev
, file
->f_mode
);
1095 zvol_release_by_inode(struct inode
*inode
, struct file
*file
)
1097 return zvol_release(inode
->i_bdev
->bd_disk
, file
->f_mode
);
1101 zvol_ioctl_by_inode(struct inode
*inode
, struct file
*file
,
1102 unsigned int cmd
, unsigned long arg
)
1104 if (file
== NULL
|| inode
== NULL
)
1106 return zvol_ioctl(inode
->i_bdev
, file
->f_mode
, cmd
, arg
);
1109 # ifdef CONFIG_COMPAT
1111 zvol_compat_ioctl_by_inode(struct file
*file
,
1112 unsigned int cmd
, unsigned long arg
)
1116 return zvol_compat_ioctl(file
->f_dentry
->d_inode
->i_bdev
,
1117 file
->f_mode
, cmd
, arg
);
1120 # define zvol_compat_ioctl_by_inode NULL
1123 static struct block_device_operations zvol_ops
= {
1124 .open
= zvol_open_by_inode
,
1125 .release
= zvol_release_by_inode
,
1126 .ioctl
= zvol_ioctl_by_inode
,
1127 .compat_ioctl
= zvol_compat_ioctl_by_inode
,
1128 .media_changed
= zvol_media_changed
,
1129 .revalidate_disk
= zvol_revalidate_disk
,
1130 .getgeo
= zvol_getgeo
,
1131 .owner
= THIS_MODULE
,
1133 #endif /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1136 * Allocate memory for a new zvol_state_t and setup the required
1137 * request queue and generic disk structures for the block device.
1139 static zvol_state_t
*
1140 zvol_alloc(dev_t dev
, const char *name
)
1144 zv
= kmem_zalloc(sizeof (zvol_state_t
), KM_SLEEP
);
1148 zv
->zv_queue
= blk_init_queue(zvol_request
, &zv
->zv_lock
);
1149 if (zv
->zv_queue
== NULL
)
1152 #ifdef HAVE_BLK_QUEUE_FLUSH
1153 blk_queue_flush(zv
->zv_queue
, VDEV_REQ_FLUSH
| VDEV_REQ_FUA
);
1155 blk_queue_ordered(zv
->zv_queue
, QUEUE_ORDERED_DRAIN
, NULL
);
1156 #endif /* HAVE_BLK_QUEUE_FLUSH */
1158 zv
->zv_disk
= alloc_disk(ZVOL_MINORS
);
1159 if (zv
->zv_disk
== NULL
)
1162 zv
->zv_queue
->queuedata
= zv
;
1164 zv
->zv_open_count
= 0;
1165 strlcpy(zv
->zv_name
, name
, MAXNAMELEN
);
1167 mutex_init(&zv
->zv_znode
.z_range_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1168 avl_create(&zv
->zv_znode
.z_range_avl
, zfs_range_compare
,
1169 sizeof (rl_t
), offsetof(rl_t
, r_node
));
1170 zv
->zv_znode
.z_is_zvol
= TRUE
;
1172 spin_lock_init(&zv
->zv_lock
);
1173 list_link_init(&zv
->zv_next
);
1175 zv
->zv_disk
->major
= zvol_major
;
1176 zv
->zv_disk
->first_minor
= (dev
& MINORMASK
);
1177 zv
->zv_disk
->fops
= &zvol_ops
;
1178 zv
->zv_disk
->private_data
= zv
;
1179 zv
->zv_disk
->queue
= zv
->zv_queue
;
1180 snprintf(zv
->zv_disk
->disk_name
, DISK_NAME_LEN
, "%s%d",
1181 ZVOL_DEV_NAME
, (dev
& MINORMASK
));
1186 blk_cleanup_queue(zv
->zv_queue
);
1188 kmem_free(zv
, sizeof (zvol_state_t
));
1194 * Cleanup then free a zvol_state_t which was created by zvol_alloc().
1197 zvol_free(zvol_state_t
*zv
)
1199 avl_destroy(&zv
->zv_znode
.z_range_avl
);
1200 mutex_destroy(&zv
->zv_znode
.z_range_lock
);
1202 del_gendisk(zv
->zv_disk
);
1203 blk_cleanup_queue(zv
->zv_queue
);
1204 put_disk(zv
->zv_disk
);
1206 kmem_free(zv
, sizeof (zvol_state_t
));
1210 __zvol_create_minor(const char *name
)
1214 dmu_object_info_t
*doi
;
1219 ASSERT(MUTEX_HELD(&zvol_state_lock
));
1221 zv
= zvol_find_by_name(name
);
1227 doi
= kmem_alloc(sizeof(dmu_object_info_t
), KM_SLEEP
);
1229 error
= dmu_objset_own(name
, DMU_OST_ZVOL
, B_TRUE
, zvol_tag
, &os
);
1233 error
= dmu_object_info(os
, ZVOL_OBJ
, doi
);
1235 goto out_dmu_objset_disown
;
1237 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
);
1239 goto out_dmu_objset_disown
;
1241 error
= zvol_find_minor(&minor
);
1243 goto out_dmu_objset_disown
;
1245 zv
= zvol_alloc(MKDEV(zvol_major
, minor
), name
);
1248 goto out_dmu_objset_disown
;
1251 if (dmu_objset_is_snapshot(os
))
1252 zv
->zv_flags
|= ZVOL_RDONLY
;
1254 zv
->zv_volblocksize
= doi
->doi_data_block_size
;
1255 zv
->zv_volsize
= volsize
;
1258 set_capacity(zv
->zv_disk
, zv
->zv_volsize
>> 9);
1260 blk_queue_max_hw_sectors(zv
->zv_queue
, UINT_MAX
);
1261 blk_queue_max_segments(zv
->zv_queue
, UINT16_MAX
);
1262 blk_queue_max_segment_size(zv
->zv_queue
, UINT_MAX
);
1263 blk_queue_physical_block_size(zv
->zv_queue
, zv
->zv_volblocksize
);
1264 blk_queue_io_opt(zv
->zv_queue
, zv
->zv_volblocksize
);
1265 #ifdef HAVE_BLK_QUEUE_DISCARD
1266 blk_queue_max_discard_sectors(zv
->zv_queue
,
1267 (zvol_max_discard_blocks
* zv
->zv_volblocksize
) >> 9);
1268 blk_queue_discard_granularity(zv
->zv_queue
, zv
->zv_volblocksize
);
1269 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD
, zv
->zv_queue
);
1271 #ifdef HAVE_BLK_QUEUE_NONROT
1272 queue_flag_set_unlocked(QUEUE_FLAG_NONROT
, zv
->zv_queue
);
1275 if (zil_replay_disable
)
1276 zil_destroy(dmu_objset_zil(os
), B_FALSE
);
1278 zil_replay(os
, zv
, zvol_replay_vector
);
1280 out_dmu_objset_disown
:
1281 dmu_objset_disown(os
, zvol_tag
);
1282 zv
->zv_objset
= NULL
;
1284 kmem_free(doi
, sizeof(dmu_object_info_t
));
1289 add_disk(zv
->zv_disk
);
1296 * Create a block device minor node and setup the linkage between it
1297 * and the specified volume. Once this function returns the block
1298 * device is live and ready for use.
1301 zvol_create_minor(const char *name
)
1305 mutex_enter(&zvol_state_lock
);
1306 error
= __zvol_create_minor(name
);
1307 mutex_exit(&zvol_state_lock
);
1313 __zvol_remove_minor(const char *name
)
1317 ASSERT(MUTEX_HELD(&zvol_state_lock
));
1319 zv
= zvol_find_by_name(name
);
1323 if (zv
->zv_open_count
> 0)
1333 * Remove a block device minor node for the specified volume.
1336 zvol_remove_minor(const char *name
)
1340 mutex_enter(&zvol_state_lock
);
1341 error
= __zvol_remove_minor(name
);
1342 mutex_exit(&zvol_state_lock
);
1348 zvol_create_minors_cb(spa_t
*spa
, uint64_t dsobj
,
1349 const char *dsname
, void *arg
)
1351 if (strchr(dsname
, '/') == NULL
)
1354 (void) __zvol_create_minor(dsname
);
1359 * Create minors for specified pool, if pool is NULL create minors
1360 * for all available pools.
1363 zvol_create_minors(const char *pool
)
1368 if (zvol_inhibit_dev
)
1371 mutex_enter(&zvol_state_lock
);
1373 error
= dmu_objset_find_spa(NULL
, pool
, zvol_create_minors_cb
,
1374 NULL
, DS_FIND_CHILDREN
| DS_FIND_SNAPSHOTS
);
1376 mutex_enter(&spa_namespace_lock
);
1377 while ((spa
= spa_next(spa
)) != NULL
) {
1378 error
= dmu_objset_find_spa(NULL
,
1379 spa_name(spa
), zvol_create_minors_cb
, NULL
,
1380 DS_FIND_CHILDREN
| DS_FIND_SNAPSHOTS
);
1384 mutex_exit(&spa_namespace_lock
);
1386 mutex_exit(&zvol_state_lock
);
1392 * Remove minors for specified pool, if pool is NULL remove all minors.
1395 zvol_remove_minors(const char *pool
)
1397 zvol_state_t
*zv
, *zv_next
;
1400 if (zvol_inhibit_dev
)
1403 str
= kmem_zalloc(MAXNAMELEN
, KM_SLEEP
);
1405 (void) strncpy(str
, pool
, strlen(pool
));
1406 (void) strcat(str
, "/");
1409 mutex_enter(&zvol_state_lock
);
1410 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
; zv
= zv_next
) {
1411 zv_next
= list_next(&zvol_state_list
, zv
);
1413 if (pool
== NULL
|| !strncmp(str
, zv
->zv_name
, strlen(str
))) {
1418 mutex_exit(&zvol_state_lock
);
1419 kmem_free(str
, MAXNAMELEN
);
1427 zvol_taskq
= taskq_create(ZVOL_DRIVER
, zvol_threads
, maxclsyspri
,
1428 zvol_threads
, INT_MAX
, TASKQ_PREPOPULATE
);
1429 if (zvol_taskq
== NULL
) {
1430 printk(KERN_INFO
"ZFS: taskq_create() failed\n");
1434 error
= register_blkdev(zvol_major
, ZVOL_DRIVER
);
1436 printk(KERN_INFO
"ZFS: register_blkdev() failed %d\n", error
);
1437 taskq_destroy(zvol_taskq
);
1441 blk_register_region(MKDEV(zvol_major
, 0), 1UL << MINORBITS
,
1442 THIS_MODULE
, zvol_probe
, NULL
, NULL
);
1444 mutex_init(&zvol_state_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1445 list_create(&zvol_state_list
, sizeof (zvol_state_t
),
1446 offsetof(zvol_state_t
, zv_next
));
1448 (void) zvol_create_minors(NULL
);
1456 zvol_remove_minors(NULL
);
1457 blk_unregister_region(MKDEV(zvol_major
, 0), 1UL << MINORBITS
);
1458 unregister_blkdev(zvol_major
, ZVOL_DRIVER
);
1459 taskq_destroy(zvol_taskq
);
1460 mutex_destroy(&zvol_state_lock
);
1461 list_destroy(&zvol_state_list
);
1464 module_param(zvol_inhibit_dev
, uint
, 0644);
1465 MODULE_PARM_DESC(zvol_inhibit_dev
, "Do not create zvol device nodes");
1467 module_param(zvol_major
, uint
, 0444);
1468 MODULE_PARM_DESC(zvol_major
, "Major number for zvol device");
1470 module_param(zvol_threads
, uint
, 0444);
1471 MODULE_PARM_DESC(zvol_threads
, "Number of threads for zvol device");
1473 module_param(zvol_max_discard_blocks
, ulong
, 0444);
1474 MODULE_PARM_DESC(zvol_max_discard_blocks
, "Max number of blocks to discard at once");