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_major
= ZVOL_MAJOR
;
50 unsigned int zvol_threads
= 0;
52 static taskq_t
*zvol_taskq
;
53 static kmutex_t zvol_state_lock
;
54 static list_t zvol_state_list
;
55 static char *zvol_tag
= "zvol_tag";
58 * The in-core state of each volume.
60 typedef struct zvol_state
{
61 char zv_name
[MAXNAMELEN
]; /* name */
62 uint64_t zv_volsize
; /* advertised space */
63 uint64_t zv_volblocksize
;/* volume block size */
64 objset_t
*zv_objset
; /* objset handle */
65 uint32_t zv_flags
; /* ZVOL_* flags */
66 uint32_t zv_open_count
; /* open counts */
67 uint32_t zv_changed
; /* disk changed */
68 zilog_t
*zv_zilog
; /* ZIL handle */
69 znode_t zv_znode
; /* for range locking */
70 dmu_buf_t
*zv_dbuf
; /* bonus handle */
71 dev_t zv_dev
; /* device id */
72 struct gendisk
*zv_disk
; /* generic disk */
73 struct request_queue
*zv_queue
; /* request queue */
74 spinlock_t zv_lock
; /* request queue lock */
75 list_node_t zv_next
; /* next zvol_state_t linkage */
78 #define ZVOL_RDONLY 0x1
81 * Find the next available range of ZVOL_MINORS minor numbers. The
82 * zvol_state_list is kept in ascending minor order so we simply need
83 * to scan the list for the first gap in the sequence. This allows us
84 * to recycle minor number as devices are created and removed.
87 zvol_find_minor(unsigned *minor
)
92 ASSERT(MUTEX_HELD(&zvol_state_lock
));
93 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
94 zv
= list_next(&zvol_state_list
, zv
), *minor
+= ZVOL_MINORS
) {
95 if (MINOR(zv
->zv_dev
) != MINOR(*minor
))
99 /* All minors are in use */
100 if (*minor
>= (1 << MINORBITS
))
107 * Find a zvol_state_t given the full major+minor dev_t.
109 static zvol_state_t
*
110 zvol_find_by_dev(dev_t dev
)
114 ASSERT(MUTEX_HELD(&zvol_state_lock
));
115 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
116 zv
= list_next(&zvol_state_list
, zv
)) {
117 if (zv
->zv_dev
== dev
)
125 * Find a zvol_state_t given the name provided at zvol_alloc() time.
127 static zvol_state_t
*
128 zvol_find_by_name(const char *name
)
132 ASSERT(MUTEX_HELD(&zvol_state_lock
));
133 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
134 zv
= list_next(&zvol_state_list
, zv
)) {
135 if (!strncmp(zv
->zv_name
, name
, MAXNAMELEN
))
143 * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation.
146 zvol_create_cb(objset_t
*os
, void *arg
, cred_t
*cr
, dmu_tx_t
*tx
)
148 zfs_creat_t
*zct
= arg
;
149 nvlist_t
*nvprops
= zct
->zct_props
;
151 uint64_t volblocksize
, volsize
;
153 VERIFY(nvlist_lookup_uint64(nvprops
,
154 zfs_prop_to_name(ZFS_PROP_VOLSIZE
), &volsize
) == 0);
155 if (nvlist_lookup_uint64(nvprops
,
156 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE
), &volblocksize
) != 0)
157 volblocksize
= zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE
);
160 * These properties must be removed from the list so the generic
161 * property setting step won't apply to them.
163 VERIFY(nvlist_remove_all(nvprops
,
164 zfs_prop_to_name(ZFS_PROP_VOLSIZE
)) == 0);
165 (void) nvlist_remove_all(nvprops
,
166 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE
));
168 error
= dmu_object_claim(os
, ZVOL_OBJ
, DMU_OT_ZVOL
, volblocksize
,
172 error
= zap_create_claim(os
, ZVOL_ZAP_OBJ
, DMU_OT_ZVOL_PROP
,
176 error
= zap_update(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
, tx
);
181 * ZFS_IOC_OBJSET_STATS entry point.
184 zvol_get_stats(objset_t
*os
, nvlist_t
*nv
)
187 dmu_object_info_t
*doi
;
190 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &val
);
194 dsl_prop_nvlist_add_uint64(nv
, ZFS_PROP_VOLSIZE
, val
);
195 doi
= kmem_alloc(sizeof(dmu_object_info_t
), KM_SLEEP
);
196 error
= dmu_object_info(os
, ZVOL_OBJ
, doi
);
199 dsl_prop_nvlist_add_uint64(nv
, ZFS_PROP_VOLBLOCKSIZE
,
200 doi
->doi_data_block_size
);
203 kmem_free(doi
, sizeof(dmu_object_info_t
));
209 * Sanity check volume size.
212 zvol_check_volsize(uint64_t volsize
, uint64_t blocksize
)
217 if (volsize
% blocksize
!= 0)
221 if (volsize
- 1 > MAXOFFSET_T
)
228 * Ensure the zap is flushed then inform the VFS of the capacity change.
231 zvol_update_volsize(zvol_state_t
*zv
, uint64_t volsize
, objset_t
*os
)
233 struct block_device
*bdev
;
237 ASSERT(MUTEX_HELD(&zvol_state_lock
));
239 tx
= dmu_tx_create(os
);
240 dmu_tx_hold_zap(tx
, ZVOL_ZAP_OBJ
, TRUE
, NULL
);
241 error
= dmu_tx_assign(tx
, TXG_WAIT
);
247 error
= zap_update(os
, ZVOL_ZAP_OBJ
, "size", 8, 1,
254 error
= dmu_free_long_range(os
,
255 ZVOL_OBJ
, volsize
, DMU_OBJECT_END
);
259 bdev
= bdget_disk(zv
->zv_disk
, 0);
264 * Added check_disk_size_change() helper function.
266 #ifdef HAVE_CHECK_DISK_SIZE_CHANGE
267 set_capacity(zv
->zv_disk
, volsize
>> 9);
268 zv
->zv_volsize
= volsize
;
269 check_disk_size_change(zv
->zv_disk
, bdev
);
271 zv
->zv_volsize
= volsize
;
273 (void) check_disk_change(bdev
);
274 #endif /* HAVE_CHECK_DISK_SIZE_CHANGE */
282 * Set ZFS_PROP_VOLSIZE set entry point.
285 zvol_set_volsize(const char *name
, uint64_t volsize
)
288 dmu_object_info_t
*doi
;
293 mutex_enter(&zvol_state_lock
);
295 zv
= zvol_find_by_name(name
);
301 doi
= kmem_alloc(sizeof(dmu_object_info_t
), KM_SLEEP
);
303 error
= dmu_objset_hold(name
, FTAG
, &os
);
307 if ((error
= dmu_object_info(os
, ZVOL_OBJ
, doi
)) != 0 ||
308 (error
= zvol_check_volsize(volsize
,doi
->doi_data_block_size
)) != 0)
311 VERIFY(dsl_prop_get_integer(name
, "readonly", &readonly
, NULL
) == 0);
317 if (get_disk_ro(zv
->zv_disk
) || (zv
->zv_flags
& ZVOL_RDONLY
)) {
322 error
= zvol_update_volsize(zv
, volsize
, os
);
324 kmem_free(doi
, sizeof(dmu_object_info_t
));
327 dmu_objset_rele(os
, FTAG
);
329 mutex_exit(&zvol_state_lock
);
335 * Sanity check volume block size.
338 zvol_check_volblocksize(uint64_t volblocksize
)
340 if (volblocksize
< SPA_MINBLOCKSIZE
||
341 volblocksize
> SPA_MAXBLOCKSIZE
||
349 * Set ZFS_PROP_VOLBLOCKSIZE set entry point.
352 zvol_set_volblocksize(const char *name
, uint64_t volblocksize
)
358 mutex_enter(&zvol_state_lock
);
360 zv
= zvol_find_by_name(name
);
366 if (get_disk_ro(zv
->zv_disk
) || (zv
->zv_flags
& ZVOL_RDONLY
)) {
371 tx
= dmu_tx_create(zv
->zv_objset
);
372 dmu_tx_hold_bonus(tx
, ZVOL_OBJ
);
373 error
= dmu_tx_assign(tx
, TXG_WAIT
);
377 error
= dmu_object_set_blocksize(zv
->zv_objset
, ZVOL_OBJ
,
378 volblocksize
, 0, tx
);
379 if (error
== ENOTSUP
)
383 zv
->zv_volblocksize
= volblocksize
;
386 mutex_exit(&zvol_state_lock
);
392 * Replay a TX_WRITE ZIL transaction that didn't get committed
393 * after a system failure
396 zvol_replay_write(zvol_state_t
*zv
, lr_write_t
*lr
, boolean_t byteswap
)
398 objset_t
*os
= zv
->zv_objset
;
399 char *data
= (char *)(lr
+ 1); /* data follows lr_write_t */
400 uint64_t off
= lr
->lr_offset
;
401 uint64_t len
= lr
->lr_length
;
406 byteswap_uint64_array(lr
, sizeof (*lr
));
408 tx
= dmu_tx_create(os
);
409 dmu_tx_hold_write(tx
, ZVOL_OBJ
, off
, len
);
410 error
= dmu_tx_assign(tx
, TXG_WAIT
);
414 dmu_write(os
, ZVOL_OBJ
, off
, len
, data
, tx
);
422 zvol_replay_err(zvol_state_t
*zv
, lr_t
*lr
, boolean_t byteswap
)
428 * Callback vectors for replaying records.
429 * Only TX_WRITE is needed for zvol.
431 zil_replay_func_t
*zvol_replay_vector
[TX_MAX_TYPE
] = {
432 (zil_replay_func_t
*)zvol_replay_err
, /* no such transaction type */
433 (zil_replay_func_t
*)zvol_replay_err
, /* TX_CREATE */
434 (zil_replay_func_t
*)zvol_replay_err
, /* TX_MKDIR */
435 (zil_replay_func_t
*)zvol_replay_err
, /* TX_MKXATTR */
436 (zil_replay_func_t
*)zvol_replay_err
, /* TX_SYMLINK */
437 (zil_replay_func_t
*)zvol_replay_err
, /* TX_REMOVE */
438 (zil_replay_func_t
*)zvol_replay_err
, /* TX_RMDIR */
439 (zil_replay_func_t
*)zvol_replay_err
, /* TX_LINK */
440 (zil_replay_func_t
*)zvol_replay_err
, /* TX_RENAME */
441 (zil_replay_func_t
*)zvol_replay_write
, /* TX_WRITE */
442 (zil_replay_func_t
*)zvol_replay_err
, /* TX_TRUNCATE */
443 (zil_replay_func_t
*)zvol_replay_err
, /* TX_SETATTR */
444 (zil_replay_func_t
*)zvol_replay_err
, /* TX_ACL */
448 * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
450 * We store data in the log buffers if it's small enough.
451 * Otherwise we will later flush the data out via dmu_sync().
453 ssize_t zvol_immediate_write_sz
= 32768;
456 zvol_log_write(zvol_state_t
*zv
, dmu_tx_t
*tx
,
457 uint64_t offset
, uint64_t size
, int sync
)
459 uint32_t blocksize
= zv
->zv_volblocksize
;
460 zilog_t
*zilog
= zv
->zv_zilog
;
463 if (zil_replaying(zilog
, tx
))
466 slogging
= spa_has_slogs(zilog
->zl_spa
);
472 itx_wr_state_t write_state
;
475 * Unlike zfs_log_write() we can be called with
476 * up to DMU_MAX_ACCESS/2 (5MB) writes.
478 if (blocksize
> zvol_immediate_write_sz
&& !slogging
&&
479 size
>= blocksize
&& offset
% blocksize
== 0) {
480 write_state
= WR_INDIRECT
; /* uses dmu_sync */
483 write_state
= WR_COPIED
;
484 len
= MIN(ZIL_MAX_LOG_DATA
, size
);
486 write_state
= WR_NEED_COPY
;
487 len
= MIN(ZIL_MAX_LOG_DATA
, size
);
490 itx
= zil_itx_create(TX_WRITE
, sizeof (*lr
) +
491 (write_state
== WR_COPIED
? len
: 0));
492 lr
= (lr_write_t
*)&itx
->itx_lr
;
493 if (write_state
== WR_COPIED
&& dmu_read(zv
->zv_objset
,
494 ZVOL_OBJ
, offset
, len
, lr
+1, DMU_READ_NO_PREFETCH
) != 0) {
495 zil_itx_destroy(itx
);
496 itx
= zil_itx_create(TX_WRITE
, sizeof (*lr
));
497 lr
= (lr_write_t
*)&itx
->itx_lr
;
498 write_state
= WR_NEED_COPY
;
501 itx
->itx_wr_state
= write_state
;
502 if (write_state
== WR_NEED_COPY
)
504 lr
->lr_foid
= ZVOL_OBJ
;
505 lr
->lr_offset
= offset
;
508 BP_ZERO(&lr
->lr_blkptr
);
510 itx
->itx_private
= zv
;
511 itx
->itx_sync
= sync
;
513 (void) zil_itx_assign(zilog
, itx
, tx
);
521 * Common write path running under the zvol taskq context. This function
522 * is responsible for copying the request structure data in to the DMU and
523 * signaling the request queue with the result of the copy.
526 zvol_write(void *arg
)
528 struct request
*req
= (struct request
*)arg
;
529 struct request_queue
*q
= req
->q
;
530 zvol_state_t
*zv
= q
->queuedata
;
531 uint64_t offset
= blk_rq_pos(req
) << 9;
532 uint64_t size
= blk_rq_bytes(req
);
537 rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_WRITER
);
539 tx
= dmu_tx_create(zv
->zv_objset
);
540 dmu_tx_hold_write(tx
, ZVOL_OBJ
, offset
, size
);
542 /* This will only fail for ENOSPC */
543 error
= dmu_tx_assign(tx
, TXG_WAIT
);
546 zfs_range_unlock(rl
);
547 blk_end_request(req
, -error
, size
);
551 error
= dmu_write_req(zv
->zv_objset
, ZVOL_OBJ
, req
, tx
);
553 zvol_log_write(zv
, tx
, offset
, size
, rq_is_sync(req
));
556 zfs_range_unlock(rl
);
559 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
561 blk_end_request(req
, -error
, size
);
565 * Common read path running under the zvol taskq context. This function
566 * is responsible for copying the requested data out of the DMU and in to
567 * a linux request structure. It then must signal the request queue with
568 * an error code describing the result of the copy.
573 struct request
*req
= (struct request
*)arg
;
574 struct request_queue
*q
= req
->q
;
575 zvol_state_t
*zv
= q
->queuedata
;
576 uint64_t offset
= blk_rq_pos(req
) << 9;
577 uint64_t size
= blk_rq_bytes(req
);
581 rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_READER
);
583 error
= dmu_read_req(zv
->zv_objset
, ZVOL_OBJ
, req
);
585 zfs_range_unlock(rl
);
587 /* convert checksum errors into IO errors */
591 blk_end_request(req
, -error
, size
);
595 * Request will be added back to the request queue and retried if
596 * it cannot be immediately dispatched to the taskq for handling
599 zvol_dispatch(task_func_t func
, struct request
*req
)
601 if (!taskq_dispatch(zvol_taskq
, func
, (void *)req
, TQ_NOSLEEP
))
602 blk_requeue_request(req
->q
, req
);
606 * Common request path. Rather than registering a custom make_request()
607 * function we use the generic Linux version. This is done because it allows
608 * us to easily merge read requests which would otherwise we performed
609 * synchronously by the DMU. This is less critical in write case where the
610 * DMU will perform the correct merging within a transaction group. Using
611 * the generic make_request() also let's use leverage the fact that the
612 * elevator with ensure correct ordering in regards to barrior IOs. On
613 * the downside it means that in the write case we end up doing request
614 * merging twice once in the elevator and once in the DMU.
616 * The request handler is called under a spin lock so all the real work
617 * is handed off to be done in the context of the zvol taskq. This function
618 * simply performs basic request sanity checking and hands off the request.
621 zvol_request(struct request_queue
*q
)
623 zvol_state_t
*zv
= q
->queuedata
;
627 while ((req
= blk_fetch_request(q
)) != NULL
) {
628 size
= blk_rq_bytes(req
);
630 if (blk_rq_pos(req
) + blk_rq_sectors(req
) >
631 get_capacity(zv
->zv_disk
)) {
633 "%s: bad access: block=%llu, count=%lu\n",
634 req
->rq_disk
->disk_name
,
635 (long long unsigned)blk_rq_pos(req
),
636 (long unsigned)blk_rq_sectors(req
));
637 __blk_end_request(req
, -EIO
, size
);
641 if (!blk_fs_request(req
)) {
642 printk(KERN_INFO
"%s: non-fs cmd\n",
643 req
->rq_disk
->disk_name
);
644 __blk_end_request(req
, -EIO
, size
);
648 switch (rq_data_dir(req
)) {
650 zvol_dispatch(zvol_read
, req
);
653 if (unlikely(get_disk_ro(zv
->zv_disk
)) ||
654 unlikely(zv
->zv_flags
& ZVOL_RDONLY
)) {
655 __blk_end_request(req
, -EROFS
, size
);
659 zvol_dispatch(zvol_write
, req
);
662 printk(KERN_INFO
"%s: unknown cmd: %d\n",
663 req
->rq_disk
->disk_name
, (int)rq_data_dir(req
));
664 __blk_end_request(req
, -EIO
, size
);
671 zvol_get_done(zgd_t
*zgd
, int error
)
674 dmu_buf_rele(zgd
->zgd_db
, zgd
);
676 zfs_range_unlock(zgd
->zgd_rl
);
678 if (error
== 0 && zgd
->zgd_bp
)
679 zil_add_block(zgd
->zgd_zilog
, zgd
->zgd_bp
);
681 kmem_free(zgd
, sizeof (zgd_t
));
685 * Get data to generate a TX_WRITE intent log record.
688 zvol_get_data(void *arg
, lr_write_t
*lr
, char *buf
, zio_t
*zio
)
690 zvol_state_t
*zv
= arg
;
691 objset_t
*os
= zv
->zv_objset
;
692 uint64_t offset
= lr
->lr_offset
;
693 uint64_t size
= lr
->lr_length
;
701 zgd
= (zgd_t
*)kmem_zalloc(sizeof (zgd_t
), KM_SLEEP
);
702 zgd
->zgd_zilog
= zv
->zv_zilog
;
703 zgd
->zgd_rl
= zfs_range_lock(&zv
->zv_znode
, offset
, size
, RL_READER
);
706 * Write records come in two flavors: immediate and indirect.
707 * For small writes it's cheaper to store the data with the
708 * log record (immediate); for large writes it's cheaper to
709 * sync the data and get a pointer to it (indirect) so that
710 * we don't have to write the data twice.
712 if (buf
!= NULL
) { /* immediate write */
713 error
= dmu_read(os
, ZVOL_OBJ
, offset
, size
, buf
,
714 DMU_READ_NO_PREFETCH
);
716 size
= zv
->zv_volblocksize
;
717 offset
= P2ALIGN_TYPED(offset
, size
, uint64_t);
718 error
= dmu_buf_hold(os
, ZVOL_OBJ
, offset
, zgd
, &db
,
719 DMU_READ_NO_PREFETCH
);
722 zgd
->zgd_bp
= &lr
->lr_blkptr
;
725 ASSERT(db
->db_offset
== offset
);
726 ASSERT(db
->db_size
== size
);
728 error
= dmu_sync(zio
, lr
->lr_common
.lrc_txg
,
736 zvol_get_done(zgd
, error
);
742 * The zvol_state_t's are inserted in increasing MINOR(dev_t) order.
745 zvol_insert(zvol_state_t
*zv_insert
)
747 zvol_state_t
*zv
= NULL
;
749 ASSERT(MUTEX_HELD(&zvol_state_lock
));
750 ASSERT3U(MINOR(zv_insert
->zv_dev
) & ZVOL_MINOR_MASK
, ==, 0);
751 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
;
752 zv
= list_next(&zvol_state_list
, zv
)) {
753 if (MINOR(zv
->zv_dev
) > MINOR(zv_insert
->zv_dev
))
757 list_insert_before(&zvol_state_list
, zv
, zv_insert
);
761 * Simply remove the zvol from to list of zvols.
764 zvol_remove(zvol_state_t
*zv_remove
)
766 ASSERT(MUTEX_HELD(&zvol_state_lock
));
767 list_remove(&zvol_state_list
, zv_remove
);
771 zvol_first_open(zvol_state_t
*zv
)
778 /* lie and say we're read-only */
779 error
= dmu_objset_own(zv
->zv_name
, DMU_OST_ZVOL
, 1, zvol_tag
, &os
);
783 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
);
785 dmu_objset_disown(os
, zvol_tag
);
790 error
= dmu_bonus_hold(os
, ZVOL_OBJ
, zvol_tag
, &zv
->zv_dbuf
);
792 dmu_objset_disown(os
, zvol_tag
);
796 set_capacity(zv
->zv_disk
, volsize
>> 9);
797 zv
->zv_volsize
= volsize
;
798 zv
->zv_zilog
= zil_open(os
, zvol_get_data
);
800 VERIFY(dsl_prop_get_integer(zv
->zv_name
, "readonly", &ro
, NULL
) == 0);
801 if (ro
|| dmu_objset_is_snapshot(os
)) {
802 set_disk_ro(zv
->zv_disk
, 1);
803 zv
->zv_flags
|= ZVOL_RDONLY
;
805 set_disk_ro(zv
->zv_disk
, 0);
806 zv
->zv_flags
&= ~ZVOL_RDONLY
;
813 zvol_last_close(zvol_state_t
*zv
)
815 zil_close(zv
->zv_zilog
);
817 dmu_buf_rele(zv
->zv_dbuf
, zvol_tag
);
819 dmu_objset_disown(zv
->zv_objset
, zvol_tag
);
820 zv
->zv_objset
= NULL
;
824 zvol_open(struct block_device
*bdev
, fmode_t flag
)
826 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
827 int error
= 0, drop_mutex
= 0;
830 * If the caller is already holding the mutex do not take it
831 * again, this will happen as part of zvol_create_minor().
832 * Once add_disk() is called the device is live and the kernel
833 * will attempt to open it to read the partition information.
835 if (!mutex_owned(&zvol_state_lock
)) {
836 mutex_enter(&zvol_state_lock
);
840 ASSERT3P(zv
, !=, NULL
);
842 if (zv
->zv_open_count
== 0) {
843 error
= zvol_first_open(zv
);
848 if ((flag
& FMODE_WRITE
) &&
849 (get_disk_ro(zv
->zv_disk
) || (zv
->zv_flags
& ZVOL_RDONLY
))) {
857 if (zv
->zv_open_count
== 0)
862 mutex_exit(&zvol_state_lock
);
864 check_disk_change(bdev
);
870 zvol_release(struct gendisk
*disk
, fmode_t mode
)
872 zvol_state_t
*zv
= disk
->private_data
;
875 if (!mutex_owned(&zvol_state_lock
)) {
876 mutex_enter(&zvol_state_lock
);
880 ASSERT3P(zv
, !=, NULL
);
881 ASSERT3U(zv
->zv_open_count
, >, 0);
883 if (zv
->zv_open_count
== 0)
887 mutex_exit(&zvol_state_lock
);
893 zvol_ioctl(struct block_device
*bdev
, fmode_t mode
,
894 unsigned int cmd
, unsigned long arg
)
896 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
904 zil_commit(zv
->zv_zilog
, ZVOL_OBJ
);
907 error
= copy_to_user((void *)arg
, zv
->zv_name
, MAXNAMELEN
);
921 zvol_compat_ioctl(struct block_device
*bdev
, fmode_t mode
,
922 unsigned cmd
, unsigned long arg
)
924 return zvol_ioctl(bdev
, mode
, cmd
, arg
);
927 #define zvol_compat_ioctl NULL
930 static int zvol_media_changed(struct gendisk
*disk
)
932 zvol_state_t
*zv
= disk
->private_data
;
934 return zv
->zv_changed
;
937 static int zvol_revalidate_disk(struct gendisk
*disk
)
939 zvol_state_t
*zv
= disk
->private_data
;
942 set_capacity(zv
->zv_disk
, zv
->zv_volsize
>> 9);
948 * Provide a simple virtual geometry for legacy compatibility. For devices
949 * smaller than 1 MiB a small head and sector count is used to allow very
950 * tiny devices. For devices over 1 Mib a standard head and sector count
951 * is used to keep the cylinders count reasonable.
954 zvol_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
956 zvol_state_t
*zv
= bdev
->bd_disk
->private_data
;
957 sector_t sectors
= get_capacity(zv
->zv_disk
);
959 if (sectors
> 2048) {
968 geo
->cylinders
= sectors
/ (geo
->heads
* geo
->sectors
);
973 static struct kobject
*
974 zvol_probe(dev_t dev
, int *part
, void *arg
)
977 struct kobject
*kobj
;
979 mutex_enter(&zvol_state_lock
);
980 zv
= zvol_find_by_dev(dev
);
981 kobj
= zv
? get_disk(zv
->zv_disk
) : ERR_PTR(-ENOENT
);
982 mutex_exit(&zvol_state_lock
);
987 #ifdef HAVE_BDEV_BLOCK_DEVICE_OPERATIONS
988 static struct block_device_operations zvol_ops
= {
990 .release
= zvol_release
,
992 .compat_ioctl
= zvol_compat_ioctl
,
993 .media_changed
= zvol_media_changed
,
994 .revalidate_disk
= zvol_revalidate_disk
,
995 .getgeo
= zvol_getgeo
,
996 .owner
= THIS_MODULE
,
999 #else /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1002 zvol_open_by_inode(struct inode
*inode
, struct file
*file
)
1004 return zvol_open(inode
->i_bdev
, file
->f_mode
);
1008 zvol_release_by_inode(struct inode
*inode
, struct file
*file
)
1010 return zvol_release(inode
->i_bdev
->bd_disk
, file
->f_mode
);
1014 zvol_ioctl_by_inode(struct inode
*inode
, struct file
*file
,
1015 unsigned int cmd
, unsigned long arg
)
1017 if (file
== NULL
|| inode
== NULL
)
1019 return zvol_ioctl(inode
->i_bdev
, file
->f_mode
, cmd
, arg
);
1022 # ifdef CONFIG_COMPAT
1024 zvol_compat_ioctl_by_inode(struct file
*file
,
1025 unsigned int cmd
, unsigned long arg
)
1029 return zvol_compat_ioctl(file
->f_dentry
->d_inode
->i_bdev
,
1030 file
->f_mode
, cmd
, arg
);
1033 # define zvol_compat_ioctl_by_inode NULL
1036 static struct block_device_operations zvol_ops
= {
1037 .open
= zvol_open_by_inode
,
1038 .release
= zvol_release_by_inode
,
1039 .ioctl
= zvol_ioctl_by_inode
,
1040 .compat_ioctl
= zvol_compat_ioctl_by_inode
,
1041 .media_changed
= zvol_media_changed
,
1042 .revalidate_disk
= zvol_revalidate_disk
,
1043 .getgeo
= zvol_getgeo
,
1044 .owner
= THIS_MODULE
,
1046 #endif /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1049 * Allocate memory for a new zvol_state_t and setup the required
1050 * request queue and generic disk structures for the block device.
1052 static zvol_state_t
*
1053 zvol_alloc(dev_t dev
, const char *name
)
1057 zv
= kmem_zalloc(sizeof (zvol_state_t
), KM_SLEEP
);
1061 zv
->zv_queue
= blk_init_queue(zvol_request
, &zv
->zv_lock
);
1062 if (zv
->zv_queue
== NULL
)
1065 zv
->zv_disk
= alloc_disk(ZVOL_MINORS
);
1066 if (zv
->zv_disk
== NULL
)
1069 zv
->zv_queue
->queuedata
= zv
;
1071 zv
->zv_open_count
= 0;
1072 strlcpy(zv
->zv_name
, name
, MAXNAMELEN
);
1074 mutex_init(&zv
->zv_znode
.z_range_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1075 avl_create(&zv
->zv_znode
.z_range_avl
, zfs_range_compare
,
1076 sizeof (rl_t
), offsetof(rl_t
, r_node
));
1077 zv
->zv_znode
.z_is_zvol
= TRUE
;
1079 spin_lock_init(&zv
->zv_lock
);
1080 list_link_init(&zv
->zv_next
);
1082 zv
->zv_disk
->major
= zvol_major
;
1083 zv
->zv_disk
->first_minor
= (dev
& MINORMASK
);
1084 zv
->zv_disk
->fops
= &zvol_ops
;
1085 zv
->zv_disk
->private_data
= zv
;
1086 zv
->zv_disk
->queue
= zv
->zv_queue
;
1087 snprintf(zv
->zv_disk
->disk_name
, DISK_NAME_LEN
, "%s%d",
1088 ZVOL_DEV_NAME
, (dev
& MINORMASK
));
1093 blk_cleanup_queue(zv
->zv_queue
);
1095 kmem_free(zv
, sizeof (zvol_state_t
));
1101 * Cleanup then free a zvol_state_t which was created by zvol_alloc().
1104 zvol_free(zvol_state_t
*zv
)
1106 avl_destroy(&zv
->zv_znode
.z_range_avl
);
1107 mutex_destroy(&zv
->zv_znode
.z_range_lock
);
1109 del_gendisk(zv
->zv_disk
);
1110 blk_cleanup_queue(zv
->zv_queue
);
1111 put_disk(zv
->zv_disk
);
1113 kmem_free(zv
, sizeof (zvol_state_t
));
1117 __zvol_create_minor(const char *name
)
1121 dmu_object_info_t
*doi
;
1126 ASSERT(MUTEX_HELD(&zvol_state_lock
));
1128 zv
= zvol_find_by_name(name
);
1134 doi
= kmem_alloc(sizeof(dmu_object_info_t
), KM_SLEEP
);
1136 error
= dmu_objset_own(name
, DMU_OST_ZVOL
, B_TRUE
, zvol_tag
, &os
);
1140 error
= dmu_object_info(os
, ZVOL_OBJ
, doi
);
1142 goto out_dmu_objset_disown
;
1144 error
= zap_lookup(os
, ZVOL_ZAP_OBJ
, "size", 8, 1, &volsize
);
1146 goto out_dmu_objset_disown
;
1148 error
= zvol_find_minor(&minor
);
1150 goto out_dmu_objset_disown
;
1152 zv
= zvol_alloc(MKDEV(zvol_major
, minor
), name
);
1155 goto out_dmu_objset_disown
;
1158 if (dmu_objset_is_snapshot(os
))
1159 zv
->zv_flags
|= ZVOL_RDONLY
;
1161 zv
->zv_volblocksize
= doi
->doi_data_block_size
;
1162 zv
->zv_volsize
= volsize
;
1165 set_capacity(zv
->zv_disk
, zv
->zv_volsize
>> 9);
1167 if (zil_replay_disable
)
1168 zil_destroy(dmu_objset_zil(os
), B_FALSE
);
1170 zil_replay(os
, zv
, zvol_replay_vector
);
1172 out_dmu_objset_disown
:
1173 dmu_objset_disown(os
, zvol_tag
);
1174 zv
->zv_objset
= NULL
;
1176 kmem_free(doi
, sizeof(dmu_object_info_t
));
1181 add_disk(zv
->zv_disk
);
1188 * Create a block device minor node and setup the linkage between it
1189 * and the specified volume. Once this function returns the block
1190 * device is live and ready for use.
1193 zvol_create_minor(const char *name
)
1197 mutex_enter(&zvol_state_lock
);
1198 error
= __zvol_create_minor(name
);
1199 mutex_exit(&zvol_state_lock
);
1205 __zvol_remove_minor(const char *name
)
1209 ASSERT(MUTEX_HELD(&zvol_state_lock
));
1211 zv
= zvol_find_by_name(name
);
1215 if (zv
->zv_open_count
> 0)
1225 * Remove a block device minor node for the specified volume.
1228 zvol_remove_minor(const char *name
)
1232 mutex_enter(&zvol_state_lock
);
1233 error
= __zvol_remove_minor(name
);
1234 mutex_exit(&zvol_state_lock
);
1240 zvol_create_minors_cb(spa_t
*spa
, uint64_t dsobj
,
1241 const char *dsname
, void *arg
)
1243 if (strchr(dsname
, '/') == NULL
)
1246 (void) __zvol_create_minor(dsname
);
1251 * Create minors for specified pool, if pool is NULL create minors
1252 * for all available pools.
1255 zvol_create_minors(const char *pool
)
1260 mutex_enter(&zvol_state_lock
);
1262 error
= dmu_objset_find_spa(NULL
, pool
, zvol_create_minors_cb
,
1263 NULL
, DS_FIND_CHILDREN
| DS_FIND_SNAPSHOTS
);
1265 mutex_enter(&spa_namespace_lock
);
1266 while ((spa
= spa_next(spa
)) != NULL
) {
1267 error
= dmu_objset_find_spa(NULL
,
1268 spa_name(spa
), zvol_create_minors_cb
, NULL
,
1269 DS_FIND_CHILDREN
| DS_FIND_SNAPSHOTS
);
1273 mutex_exit(&spa_namespace_lock
);
1275 mutex_exit(&zvol_state_lock
);
1281 * Remove minors for specified pool, if pool is NULL remove all minors.
1284 zvol_remove_minors(const char *pool
)
1286 zvol_state_t
*zv
, *zv_next
;
1289 str
= kmem_zalloc(MAXNAMELEN
, KM_SLEEP
);
1291 (void) strncpy(str
, pool
, strlen(pool
));
1292 (void) strcat(str
, "/");
1295 mutex_enter(&zvol_state_lock
);
1296 for (zv
= list_head(&zvol_state_list
); zv
!= NULL
; zv
= zv_next
) {
1297 zv_next
= list_next(&zvol_state_list
, zv
);
1299 if (pool
== NULL
|| !strncmp(str
, zv
->zv_name
, strlen(str
))) {
1304 mutex_exit(&zvol_state_lock
);
1305 kmem_free(str
, MAXNAMELEN
);
1314 zvol_threads
= num_online_cpus();
1316 zvol_taskq
= taskq_create(ZVOL_DRIVER
, zvol_threads
, maxclsyspri
,
1317 zvol_threads
, INT_MAX
, TASKQ_PREPOPULATE
);
1318 if (zvol_taskq
== NULL
) {
1319 printk(KERN_INFO
"ZFS: taskq_create() failed\n");
1323 error
= register_blkdev(zvol_major
, ZVOL_DRIVER
);
1325 printk(KERN_INFO
"ZFS: register_blkdev() failed %d\n", error
);
1326 taskq_destroy(zvol_taskq
);
1330 blk_register_region(MKDEV(zvol_major
, 0), 1UL << MINORBITS
,
1331 THIS_MODULE
, zvol_probe
, NULL
, NULL
);
1333 mutex_init(&zvol_state_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
1334 list_create(&zvol_state_list
, sizeof (zvol_state_t
),
1335 offsetof(zvol_state_t
, zv_next
));
1337 (void) zvol_create_minors(NULL
);
1345 zvol_remove_minors(NULL
);
1346 blk_unregister_region(MKDEV(zvol_major
, 0), 1UL << MINORBITS
);
1347 unregister_blkdev(zvol_major
, ZVOL_DRIVER
);
1348 taskq_destroy(zvol_taskq
);
1349 mutex_destroy(&zvol_state_lock
);
1350 list_destroy(&zvol_state_list
);
1353 module_param(zvol_major
, uint
, 0);
1354 MODULE_PARM_DESC(zvol_major
, "Major number for zvol device");
1356 module_param(zvol_threads
, uint
, 0);
1357 MODULE_PARM_DESC(zvol_threads
, "Number of threads for zvol device");