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.
37 * Copyright 2014 Nexenta Systems, Inc. All rights reserved.
38 * Copyright (c) 2016 Actifio, Inc. All rights reserved.
39 * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
43 * Note on locking of zvol state structures.
45 * These structures are used to maintain internal state used to emulate block
46 * devices on top of zvols. In particular, management of device minor number
47 * operations - create, remove, rename, and set_snapdev - involves access to
48 * these structures. The zvol_state_lock is primarily used to protect the
49 * zvol_state_list. The zv->zv_state_lock is used to protect the contents
50 * of the zvol_state_t structures, as well as to make sure that when the
51 * time comes to remove the structure from the list, it is not in use, and
52 * therefore, it can be taken off zvol_state_list and freed.
54 * The zv_suspend_lock was introduced to allow for suspending I/O to a zvol,
55 * e.g. for the duration of receive and rollback operations. This lock can be
56 * held for significant periods of time. Given that it is undesirable to hold
57 * mutexes for long periods of time, the following lock ordering applies:
58 * - take zvol_state_lock if necessary, to protect zvol_state_list
59 * - take zv_suspend_lock if necessary, by the code path in question
60 * - take zv_state_lock to protect zvol_state_t
62 * The minor operations are issued to spa->spa_zvol_taskq queues, that are
63 * single-threaded (to preserve order of minor operations), and are executed
64 * through the zvol_task_cb that dispatches the specific operations. Therefore,
65 * these operations are serialized per pool. Consequently, we can be certain
66 * that for a given zvol, there is only one operation at a time in progress.
67 * That is why one can be sure that first, zvol_state_t for a given zvol is
68 * allocated and placed on zvol_state_list, and then other minor operations
69 * for this zvol are going to proceed in the order of issue.
71 * It is also worth keeping in mind that once add_disk() is called, the zvol is
72 * announced to the world, and zvol_open()/zvol_release() can be called at any
73 * time. Incidentally, add_disk() itself calls zvol_open()->zvol_first_open()
74 * and zvol_release()->zvol_last_close() directly as well.
78 #include <sys/dmu_traverse.h>
79 #include <sys/dsl_dataset.h>
80 #include <sys/dsl_prop.h>
81 #include <sys/dsl_dir.h>
83 #include <sys/zfeature.h>
84 #include <sys/zil_impl.h>
85 #include <sys/dmu_tx.h>
87 #include <sys/zfs_rlock.h>
88 #include <sys/zfs_znode.h>
89 #include <sys/spa_impl.h>
91 #include <linux/blkdev_compat.h>
93 unsigned int zvol_inhibit_dev = 0;
94 unsigned int zvol_major = ZVOL_MAJOR;
95 unsigned int zvol_threads = 32;
96 unsigned int zvol_request_sync = 0;
97 unsigned int zvol_prefetch_bytes = (128 * 1024);
98 unsigned long zvol_max_discard_blocks = 16384;
99 unsigned int zvol_volmode = ZFS_VOLMODE_GEOM;
101 static taskq_t *zvol_taskq;
102 static kmutex_t zvol_state_lock;
103 static list_t zvol_state_list;
105 #define ZVOL_HT_SIZE 1024
106 static struct hlist_head *zvol_htable;
107 #define ZVOL_HT_HEAD(hash) (&zvol_htable[(hash) & (ZVOL_HT_SIZE-1)])
109 static struct ida zvol_ida;
112 * The in-core state of each volume.
115 char zv_name[MAXNAMELEN]; /* name */
116 uint64_t zv_volsize; /* advertised space */
117 uint64_t zv_volblocksize; /* volume block size */
118 objset_t *zv_objset; /* objset handle */
119 uint32_t zv_flags; /* ZVOL_* flags */
120 uint32_t zv_open_count; /* open counts */
121 uint32_t zv_changed; /* disk changed */
122 zilog_t *zv_zilog; /* ZIL handle */
123 zfs_rlock_t zv_range_lock; /* range lock */
124 dnode_t *zv_dn; /* dnode hold */
125 dev_t zv_dev; /* device id */
126 struct gendisk *zv_disk; /* generic disk */
127 struct request_queue *zv_queue; /* request queue */
128 list_node_t zv_next; /* next zvol_state_t linkage */
129 uint64_t zv_hash; /* name hash */
130 struct hlist_node zv_hlink; /* hash link */
131 kmutex_t zv_state_lock; /* protects zvol_state_t */
132 atomic_t zv_suspend_ref; /* refcount for suspend */
133 krwlock_t zv_suspend_lock; /* suspend lock */
137 ZVOL_ASYNC_CREATE_MINORS,
138 ZVOL_ASYNC_REMOVE_MINORS,
139 ZVOL_ASYNC_RENAME_MINORS,
140 ZVOL_ASYNC_SET_SNAPDEV,
141 ZVOL_ASYNC_SET_VOLMODE,
147 char pool[MAXNAMELEN];
148 char name1[MAXNAMELEN];
149 char name2[MAXNAMELEN];
150 zprop_source_t source;
154 #define ZVOL_RDONLY 0x1
157 zvol_name_hash(const char *name)
160 uint64_t crc = -1ULL;
161 uint8_t *p = (uint8_t *)name;
162 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
163 for (i = 0; i < MAXNAMELEN - 1 && *p; i++, p++) {
164 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (*p)) & 0xFF];
170 * Find a zvol_state_t given the full major+minor dev_t. If found,
171 * return with zv_state_lock taken, otherwise, return (NULL) without
172 * taking zv_state_lock.
174 static zvol_state_t *
175 zvol_find_by_dev(dev_t dev)
179 mutex_enter(&zvol_state_lock);
180 for (zv = list_head(&zvol_state_list); zv != NULL;
181 zv = list_next(&zvol_state_list, zv)) {
182 mutex_enter(&zv->zv_state_lock);
183 if (zv->zv_dev == dev) {
184 mutex_exit(&zvol_state_lock);
187 mutex_exit(&zv->zv_state_lock);
189 mutex_exit(&zvol_state_lock);
195 * Find a zvol_state_t given the name and hash generated by zvol_name_hash.
196 * If found, return with zv_suspend_lock and zv_state_lock taken, otherwise,
197 * return (NULL) without the taking locks. The zv_suspend_lock is always taken
198 * before zv_state_lock. The mode argument indicates the mode (including none)
199 * for zv_suspend_lock to be taken.
201 static zvol_state_t *
202 zvol_find_by_name_hash(const char *name, uint64_t hash, int mode)
205 struct hlist_node *p = NULL;
207 mutex_enter(&zvol_state_lock);
208 hlist_for_each(p, ZVOL_HT_HEAD(hash)) {
209 zv = hlist_entry(p, zvol_state_t, zv_hlink);
210 mutex_enter(&zv->zv_state_lock);
211 if (zv->zv_hash == hash &&
212 strncmp(zv->zv_name, name, MAXNAMELEN) == 0) {
214 * this is the right zvol, take the locks in the
217 if (mode != RW_NONE &&
218 !rw_tryenter(&zv->zv_suspend_lock, mode)) {
219 mutex_exit(&zv->zv_state_lock);
220 rw_enter(&zv->zv_suspend_lock, mode);
221 mutex_enter(&zv->zv_state_lock);
223 * zvol cannot be renamed as we continue
224 * to hold zvol_state_lock
226 ASSERT(zv->zv_hash == hash &&
227 strncmp(zv->zv_name, name, MAXNAMELEN)
230 mutex_exit(&zvol_state_lock);
233 mutex_exit(&zv->zv_state_lock);
235 mutex_exit(&zvol_state_lock);
241 * Find a zvol_state_t given the name.
242 * If found, return with zv_suspend_lock and zv_state_lock taken, otherwise,
243 * return (NULL) without the taking locks. The zv_suspend_lock is always taken
244 * before zv_state_lock. The mode argument indicates the mode (including none)
245 * for zv_suspend_lock to be taken.
247 static zvol_state_t *
248 zvol_find_by_name(const char *name, int mode)
250 return (zvol_find_by_name_hash(name, zvol_name_hash(name), mode));
255 * Given a path, return TRUE if path is a ZVOL.
258 zvol_is_zvol(const char *device)
260 struct block_device *bdev;
263 bdev = vdev_lookup_bdev(device);
267 major = MAJOR(bdev->bd_dev);
270 if (major == zvol_major)
277 * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation.
280 zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
282 zfs_creat_t *zct = arg;
283 nvlist_t *nvprops = zct->zct_props;
285 uint64_t volblocksize, volsize;
287 VERIFY(nvlist_lookup_uint64(nvprops,
288 zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
289 if (nvlist_lookup_uint64(nvprops,
290 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
291 volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);
294 * These properties must be removed from the list so the generic
295 * property setting step won't apply to them.
297 VERIFY(nvlist_remove_all(nvprops,
298 zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
299 (void) nvlist_remove_all(nvprops,
300 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE));
302 error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize,
306 error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP,
310 error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx);
315 * ZFS_IOC_OBJSET_STATS entry point.
318 zvol_get_stats(objset_t *os, nvlist_t *nv)
321 dmu_object_info_t *doi;
324 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val);
326 return (SET_ERROR(error));
328 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);
329 doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
330 error = dmu_object_info(os, ZVOL_OBJ, doi);
333 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE,
334 doi->doi_data_block_size);
337 kmem_free(doi, sizeof (dmu_object_info_t));
339 return (SET_ERROR(error));
343 zvol_size_changed(zvol_state_t *zv, uint64_t volsize)
345 struct block_device *bdev;
347 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
349 bdev = bdget_disk(zv->zv_disk, 0);
353 set_capacity(zv->zv_disk, volsize >> 9);
354 zv->zv_volsize = volsize;
355 check_disk_size_change(zv->zv_disk, bdev);
361 * Sanity check volume size.
364 zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
367 return (SET_ERROR(EINVAL));
369 if (volsize % blocksize != 0)
370 return (SET_ERROR(EINVAL));
373 if (volsize - 1 > SPEC_MAXOFFSET_T)
374 return (SET_ERROR(EOVERFLOW));
380 * Ensure the zap is flushed then inform the VFS of the capacity change.
383 zvol_update_volsize(uint64_t volsize, objset_t *os)
389 tx = dmu_tx_create(os);
390 dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
391 dmu_tx_mark_netfree(tx);
392 error = dmu_tx_assign(tx, TXG_WAIT);
395 return (SET_ERROR(error));
397 txg = dmu_tx_get_txg(tx);
399 error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
403 txg_wait_synced(dmu_objset_pool(os), txg);
406 error = dmu_free_long_range(os,
407 ZVOL_OBJ, volsize, DMU_OBJECT_END);
413 zvol_update_live_volsize(zvol_state_t *zv, uint64_t volsize)
415 zvol_size_changed(zv, volsize);
418 * We should post a event here describing the expansion. However,
419 * the zfs_ereport_post() interface doesn't nicely support posting
420 * events for zvols, it assumes events relate to vdevs or zios.
427 * Set ZFS_PROP_VOLSIZE set entry point.
430 zvol_set_volsize(const char *name, uint64_t volsize)
432 zvol_state_t *zv = NULL;
435 dmu_object_info_t *doi;
437 boolean_t owned = B_FALSE;
439 error = dsl_prop_get_integer(name,
440 zfs_prop_to_name(ZFS_PROP_READONLY), &readonly, NULL);
442 return (SET_ERROR(error));
444 return (SET_ERROR(EROFS));
446 zv = zvol_find_by_name(name, RW_READER);
448 ASSERT(zv == NULL || (MUTEX_HELD(&zv->zv_state_lock) &&
449 RW_READ_HELD(&zv->zv_suspend_lock)));
451 if (zv == NULL || zv->zv_objset == NULL) {
453 rw_exit(&zv->zv_suspend_lock);
454 if ((error = dmu_objset_own(name, DMU_OST_ZVOL, B_FALSE,
457 mutex_exit(&zv->zv_state_lock);
458 return (SET_ERROR(error));
467 doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
469 if ((error = dmu_object_info(os, ZVOL_OBJ, doi)) ||
470 (error = zvol_check_volsize(volsize, doi->doi_data_block_size)))
473 error = zvol_update_volsize(volsize, os);
475 if (error == 0 && zv != NULL)
476 error = zvol_update_live_volsize(zv, volsize);
478 kmem_free(doi, sizeof (dmu_object_info_t));
481 dmu_objset_disown(os, FTAG);
483 zv->zv_objset = NULL;
485 rw_exit(&zv->zv_suspend_lock);
489 mutex_exit(&zv->zv_state_lock);
491 return (SET_ERROR(error));
495 * Sanity check volume block size.
498 zvol_check_volblocksize(const char *name, uint64_t volblocksize)
500 /* Record sizes above 128k need the feature to be enabled */
501 if (volblocksize > SPA_OLD_MAXBLOCKSIZE) {
505 if ((error = spa_open(name, &spa, FTAG)) != 0)
508 if (!spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS)) {
509 spa_close(spa, FTAG);
510 return (SET_ERROR(ENOTSUP));
514 * We don't allow setting the property above 1MB,
515 * unless the tunable has been changed.
517 if (volblocksize > zfs_max_recordsize)
518 return (SET_ERROR(EDOM));
520 spa_close(spa, FTAG);
523 if (volblocksize < SPA_MINBLOCKSIZE ||
524 volblocksize > SPA_MAXBLOCKSIZE ||
526 return (SET_ERROR(EDOM));
532 * Set ZFS_PROP_VOLBLOCKSIZE set entry point.
535 zvol_set_volblocksize(const char *name, uint64_t volblocksize)
541 zv = zvol_find_by_name(name, RW_READER);
544 return (SET_ERROR(ENXIO));
546 ASSERT(MUTEX_HELD(&zv->zv_state_lock) &&
547 RW_READ_HELD(&zv->zv_suspend_lock));
549 if (zv->zv_flags & ZVOL_RDONLY) {
550 mutex_exit(&zv->zv_state_lock);
551 rw_exit(&zv->zv_suspend_lock);
552 return (SET_ERROR(EROFS));
555 tx = dmu_tx_create(zv->zv_objset);
556 dmu_tx_hold_bonus(tx, ZVOL_OBJ);
557 error = dmu_tx_assign(tx, TXG_WAIT);
561 error = dmu_object_set_blocksize(zv->zv_objset, ZVOL_OBJ,
562 volblocksize, 0, tx);
563 if (error == ENOTSUP)
564 error = SET_ERROR(EBUSY);
567 zv->zv_volblocksize = volblocksize;
570 mutex_exit(&zv->zv_state_lock);
571 rw_exit(&zv->zv_suspend_lock);
573 return (SET_ERROR(error));
577 * Replay a TX_TRUNCATE ZIL transaction if asked. TX_TRUNCATE is how we
578 * implement DKIOCFREE/free-long-range.
581 zvol_replay_truncate(zvol_state_t *zv, lr_truncate_t *lr, boolean_t byteswap)
583 uint64_t offset, length;
586 byteswap_uint64_array(lr, sizeof (*lr));
588 offset = lr->lr_offset;
589 length = lr->lr_length;
591 return (dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, offset, length));
595 * Replay a TX_WRITE ZIL transaction that didn't get committed
596 * after a system failure
599 zvol_replay_write(zvol_state_t *zv, lr_write_t *lr, boolean_t byteswap)
601 objset_t *os = zv->zv_objset;
602 char *data = (char *)(lr + 1); /* data follows lr_write_t */
603 uint64_t offset, length;
608 byteswap_uint64_array(lr, sizeof (*lr));
610 offset = lr->lr_offset;
611 length = lr->lr_length;
613 /* If it's a dmu_sync() block, write the whole block */
614 if (lr->lr_common.lrc_reclen == sizeof (lr_write_t)) {
615 uint64_t blocksize = BP_GET_LSIZE(&lr->lr_blkptr);
616 if (length < blocksize) {
617 offset -= offset % blocksize;
622 tx = dmu_tx_create(os);
623 dmu_tx_hold_write(tx, ZVOL_OBJ, offset, length);
624 error = dmu_tx_assign(tx, TXG_WAIT);
628 dmu_write(os, ZVOL_OBJ, offset, length, data, tx);
636 zvol_replay_err(zvol_state_t *zv, lr_t *lr, boolean_t byteswap)
638 return (SET_ERROR(ENOTSUP));
642 * Callback vectors for replaying records.
643 * Only TX_WRITE and TX_TRUNCATE are needed for zvol.
645 zil_replay_func_t zvol_replay_vector[TX_MAX_TYPE] = {
646 (zil_replay_func_t)zvol_replay_err, /* no such transaction type */
647 (zil_replay_func_t)zvol_replay_err, /* TX_CREATE */
648 (zil_replay_func_t)zvol_replay_err, /* TX_MKDIR */
649 (zil_replay_func_t)zvol_replay_err, /* TX_MKXATTR */
650 (zil_replay_func_t)zvol_replay_err, /* TX_SYMLINK */
651 (zil_replay_func_t)zvol_replay_err, /* TX_REMOVE */
652 (zil_replay_func_t)zvol_replay_err, /* TX_RMDIR */
653 (zil_replay_func_t)zvol_replay_err, /* TX_LINK */
654 (zil_replay_func_t)zvol_replay_err, /* TX_RENAME */
655 (zil_replay_func_t)zvol_replay_write, /* TX_WRITE */
656 (zil_replay_func_t)zvol_replay_truncate, /* TX_TRUNCATE */
657 (zil_replay_func_t)zvol_replay_err, /* TX_SETATTR */
658 (zil_replay_func_t)zvol_replay_err, /* TX_ACL */
662 * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
664 * We store data in the log buffers if it's small enough.
665 * Otherwise we will later flush the data out via dmu_sync().
667 ssize_t zvol_immediate_write_sz = 32768;
670 zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, uint64_t offset,
671 uint64_t size, int sync)
673 uint32_t blocksize = zv->zv_volblocksize;
674 zilog_t *zilog = zv->zv_zilog;
675 itx_wr_state_t write_state;
677 if (zil_replaying(zilog, tx))
680 if (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
681 write_state = WR_INDIRECT;
682 else if (!spa_has_slogs(zilog->zl_spa) &&
683 size >= blocksize && blocksize > zvol_immediate_write_sz)
684 write_state = WR_INDIRECT;
686 write_state = WR_COPIED;
688 write_state = WR_NEED_COPY;
693 itx_wr_state_t wr_state = write_state;
696 if (wr_state == WR_COPIED && size > ZIL_MAX_COPIED_DATA)
697 wr_state = WR_NEED_COPY;
698 else if (wr_state == WR_INDIRECT)
699 len = MIN(blocksize - P2PHASE(offset, blocksize), size);
701 itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
702 (wr_state == WR_COPIED ? len : 0));
703 lr = (lr_write_t *)&itx->itx_lr;
704 if (wr_state == WR_COPIED && dmu_read_by_dnode(zv->zv_dn,
705 offset, len, lr+1, DMU_READ_NO_PREFETCH) != 0) {
706 zil_itx_destroy(itx);
707 itx = zil_itx_create(TX_WRITE, sizeof (*lr));
708 lr = (lr_write_t *)&itx->itx_lr;
709 wr_state = WR_NEED_COPY;
712 itx->itx_wr_state = wr_state;
713 lr->lr_foid = ZVOL_OBJ;
714 lr->lr_offset = offset;
717 BP_ZERO(&lr->lr_blkptr);
719 itx->itx_private = zv;
720 itx->itx_sync = sync;
722 (void) zil_itx_assign(zilog, itx, tx);
729 typedef struct zv_request {
736 uio_from_bio(uio_t *uio, struct bio *bio)
738 uio->uio_bvec = &bio->bi_io_vec[BIO_BI_IDX(bio)];
739 uio->uio_skip = BIO_BI_SKIP(bio);
740 uio->uio_resid = BIO_BI_SIZE(bio);
741 uio->uio_iovcnt = bio->bi_vcnt - BIO_BI_IDX(bio);
742 uio->uio_loffset = BIO_BI_SECTOR(bio) << 9;
743 uio->uio_limit = MAXOFFSET_T;
744 uio->uio_segflg = UIO_BVEC;
748 zvol_write(void *arg)
750 zv_request_t *zvr = arg;
751 struct bio *bio = zvr->bio;
753 zvol_state_t *zv = zvr->zv;
754 uint64_t volsize = zv->zv_volsize;
757 unsigned long start_jif;
759 uio_from_bio(&uio, bio);
761 ASSERT(zv && zv->zv_open_count > 0);
764 blk_generic_start_io_acct(zv->zv_queue, WRITE, bio_sectors(bio),
765 &zv->zv_disk->part0);
767 sync = bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
769 while (uio.uio_resid > 0 && uio.uio_loffset < volsize) {
770 uint64_t bytes = MIN(uio.uio_resid, DMU_MAX_ACCESS >> 1);
771 uint64_t off = uio.uio_loffset;
772 dmu_tx_t *tx = dmu_tx_create(zv->zv_objset);
774 if (bytes > volsize - off) /* don't write past the end */
775 bytes = volsize - off;
777 dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
779 /* This will only fail for ENOSPC */
780 error = dmu_tx_assign(tx, TXG_WAIT);
785 error = dmu_write_uio_dnode(zv->zv_dn, &uio, bytes, tx);
787 zvol_log_write(zv, tx, off, bytes, sync);
793 zfs_range_unlock(zvr->rl);
795 zil_commit(zv->zv_zilog, ZVOL_OBJ);
797 rw_exit(&zv->zv_suspend_lock);
798 blk_generic_end_io_acct(zv->zv_queue, WRITE, &zv->zv_disk->part0,
800 BIO_END_IO(bio, -error);
801 kmem_free(zvr, sizeof (zv_request_t));
805 * Log a DKIOCFREE/free-long-range to the ZIL with TX_TRUNCATE.
808 zvol_log_truncate(zvol_state_t *zv, dmu_tx_t *tx, uint64_t off, uint64_t len,
813 zilog_t *zilog = zv->zv_zilog;
815 if (zil_replaying(zilog, tx))
818 itx = zil_itx_create(TX_TRUNCATE, sizeof (*lr));
819 lr = (lr_truncate_t *)&itx->itx_lr;
820 lr->lr_foid = ZVOL_OBJ;
824 itx->itx_sync = sync;
825 zil_itx_assign(zilog, itx, tx);
829 zvol_discard(void *arg)
831 zv_request_t *zvr = arg;
832 struct bio *bio = zvr->bio;
833 zvol_state_t *zv = zvr->zv;
834 uint64_t start = BIO_BI_SECTOR(bio) << 9;
835 uint64_t size = BIO_BI_SIZE(bio);
836 uint64_t end = start + size;
840 unsigned long start_jif;
842 ASSERT(zv && zv->zv_open_count > 0);
845 blk_generic_start_io_acct(zv->zv_queue, WRITE, bio_sectors(bio),
846 &zv->zv_disk->part0);
848 sync = bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
850 if (end > zv->zv_volsize) {
851 error = SET_ERROR(EIO);
856 * Align the request to volume block boundaries when a secure erase is
857 * not required. This will prevent dnode_free_range() from zeroing out
858 * the unaligned parts which is slow (read-modify-write) and useless
859 * since we are not freeing any space by doing so.
861 if (!bio_is_secure_erase(bio)) {
862 start = P2ROUNDUP(start, zv->zv_volblocksize);
863 end = P2ALIGN(end, zv->zv_volblocksize);
870 tx = dmu_tx_create(zv->zv_objset);
871 dmu_tx_mark_netfree(tx);
872 error = dmu_tx_assign(tx, TXG_WAIT);
876 zvol_log_truncate(zv, tx, start, size, B_TRUE);
878 error = dmu_free_long_range(zv->zv_objset,
879 ZVOL_OBJ, start, size);
882 zfs_range_unlock(zvr->rl);
883 if (error == 0 && sync)
884 zil_commit(zv->zv_zilog, ZVOL_OBJ);
886 rw_exit(&zv->zv_suspend_lock);
887 blk_generic_end_io_acct(zv->zv_queue, WRITE, &zv->zv_disk->part0,
889 BIO_END_IO(bio, -error);
890 kmem_free(zvr, sizeof (zv_request_t));
896 zv_request_t *zvr = arg;
897 struct bio *bio = zvr->bio;
899 zvol_state_t *zv = zvr->zv;
900 uint64_t volsize = zv->zv_volsize;
902 unsigned long start_jif;
904 uio_from_bio(&uio, bio);
906 ASSERT(zv && zv->zv_open_count > 0);
909 blk_generic_start_io_acct(zv->zv_queue, READ, bio_sectors(bio),
910 &zv->zv_disk->part0);
912 while (uio.uio_resid > 0 && uio.uio_loffset < volsize) {
913 uint64_t bytes = MIN(uio.uio_resid, DMU_MAX_ACCESS >> 1);
915 /* don't read past the end */
916 if (bytes > volsize - uio.uio_loffset)
917 bytes = volsize - uio.uio_loffset;
919 error = dmu_read_uio_dnode(zv->zv_dn, &uio, bytes);
921 /* convert checksum errors into IO errors */
923 error = SET_ERROR(EIO);
927 zfs_range_unlock(zvr->rl);
929 rw_exit(&zv->zv_suspend_lock);
930 blk_generic_end_io_acct(zv->zv_queue, READ, &zv->zv_disk->part0,
932 BIO_END_IO(bio, -error);
933 kmem_free(zvr, sizeof (zv_request_t));
936 static MAKE_REQUEST_FN_RET
937 zvol_request(struct request_queue *q, struct bio *bio)
939 zvol_state_t *zv = q->queuedata;
940 fstrans_cookie_t cookie = spl_fstrans_mark();
941 uint64_t offset = BIO_BI_SECTOR(bio) << 9;
942 uint64_t size = BIO_BI_SIZE(bio);
943 int rw = bio_data_dir(bio);
946 if (bio_has_data(bio) && offset + size > zv->zv_volsize) {
948 "%s: bad access: offset=%llu, size=%lu\n",
949 zv->zv_disk->disk_name,
950 (long long unsigned)offset,
951 (long unsigned)size);
953 BIO_END_IO(bio, -SET_ERROR(EIO));
958 boolean_t need_sync = B_FALSE;
960 if (unlikely(zv->zv_flags & ZVOL_RDONLY)) {
961 BIO_END_IO(bio, -SET_ERROR(EROFS));
966 * To be released in the I/O function. See the comment on
967 * zfs_range_lock below.
969 rw_enter(&zv->zv_suspend_lock, RW_READER);
971 /* bio marked as FLUSH need to flush before write */
972 if (bio_is_flush(bio))
973 zil_commit(zv->zv_zilog, ZVOL_OBJ);
975 /* Some requests are just for flush and nothing else. */
977 rw_exit(&zv->zv_suspend_lock);
982 zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
987 * To be released in the I/O function. Since the I/O functions
988 * are asynchronous, we take it here synchronously to make
989 * sure overlapped I/Os are properly ordered.
991 zvr->rl = zfs_range_lock(&zv->zv_range_lock, offset, size,
994 * Sync writes and discards execute zil_commit() which may need
995 * to take a RL_READER lock on the whole block being modified
996 * via its zillog->zl_get_data(): to avoid circular dependency
997 * issues with taskq threads execute these requests
998 * synchronously here in zvol_request().
1000 need_sync = bio_is_fua(bio) ||
1001 zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
1002 if (bio_is_discard(bio) || bio_is_secure_erase(bio)) {
1003 if (zvol_request_sync || need_sync ||
1004 taskq_dispatch(zvol_taskq, zvol_discard, zvr,
1005 TQ_SLEEP) == TASKQID_INVALID)
1008 if (zvol_request_sync || need_sync ||
1009 taskq_dispatch(zvol_taskq, zvol_write, zvr,
1010 TQ_SLEEP) == TASKQID_INVALID)
1014 zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
1018 rw_enter(&zv->zv_suspend_lock, RW_READER);
1020 zvr->rl = zfs_range_lock(&zv->zv_range_lock, offset, size,
1022 if (zvol_request_sync || taskq_dispatch(zvol_taskq,
1023 zvol_read, zvr, TQ_SLEEP) == TASKQID_INVALID)
1028 spl_fstrans_unmark(cookie);
1029 #ifdef HAVE_MAKE_REQUEST_FN_RET_INT
1031 #elif defined(HAVE_MAKE_REQUEST_FN_RET_QC)
1032 return (BLK_QC_T_NONE);
1037 zvol_get_done(zgd_t *zgd, int error)
1040 dmu_buf_rele(zgd->zgd_db, zgd);
1042 zfs_range_unlock(zgd->zgd_rl);
1044 if (error == 0 && zgd->zgd_bp)
1045 zil_add_block(zgd->zgd_zilog, zgd->zgd_bp);
1047 kmem_free(zgd, sizeof (zgd_t));
1051 * Get data to generate a TX_WRITE intent log record.
1054 zvol_get_data(void *arg, lr_write_t *lr, char *buf, zio_t *zio)
1056 zvol_state_t *zv = arg;
1057 uint64_t offset = lr->lr_offset;
1058 uint64_t size = lr->lr_length;
1063 ASSERT(zio != NULL);
1066 zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
1067 zgd->zgd_zilog = zv->zv_zilog;
1070 * Write records come in two flavors: immediate and indirect.
1071 * For small writes it's cheaper to store the data with the
1072 * log record (immediate); for large writes it's cheaper to
1073 * sync the data and get a pointer to it (indirect) so that
1074 * we don't have to write the data twice.
1076 if (buf != NULL) { /* immediate write */
1077 zgd->zgd_rl = zfs_range_lock(&zv->zv_range_lock, offset, size,
1079 error = dmu_read_by_dnode(zv->zv_dn, offset, size, buf,
1080 DMU_READ_NO_PREFETCH);
1081 } else { /* indirect write */
1083 * Have to lock the whole block to ensure when it's written out
1084 * and its checksum is being calculated that no one can change
1085 * the data. Contrarily to zfs_get_data we need not re-check
1086 * blocksize after we get the lock because it cannot be changed.
1088 size = zv->zv_volblocksize;
1089 offset = P2ALIGN_TYPED(offset, size, uint64_t);
1090 zgd->zgd_rl = zfs_range_lock(&zv->zv_range_lock, offset, size,
1092 error = dmu_buf_hold_by_dnode(zv->zv_dn, offset, zgd, &db,
1093 DMU_READ_NO_PREFETCH);
1095 blkptr_t *bp = &lr->lr_blkptr;
1101 ASSERT(db->db_offset == offset);
1102 ASSERT(db->db_size == size);
1104 error = dmu_sync(zio, lr->lr_common.lrc_txg,
1105 zvol_get_done, zgd);
1112 zvol_get_done(zgd, error);
1114 return (SET_ERROR(error));
1118 * The zvol_state_t's are inserted into zvol_state_list and zvol_htable.
1121 zvol_insert(zvol_state_t *zv)
1123 ASSERT(MUTEX_HELD(&zvol_state_lock));
1124 ASSERT3U(MINOR(zv->zv_dev) & ZVOL_MINOR_MASK, ==, 0);
1125 list_insert_head(&zvol_state_list, zv);
1126 hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));
1130 * Simply remove the zvol from to list of zvols.
1133 zvol_remove(zvol_state_t *zv)
1135 ASSERT(MUTEX_HELD(&zvol_state_lock));
1136 list_remove(&zvol_state_list, zv);
1137 hlist_del(&zv->zv_hlink);
1141 * Setup zv after we just own the zv->objset
1144 zvol_setup_zv(zvol_state_t *zv)
1149 objset_t *os = zv->zv_objset;
1151 ASSERT(MUTEX_HELD(&zv->zv_state_lock) &&
1152 RW_LOCK_HELD(&zv->zv_suspend_lock));
1154 error = dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL);
1156 return (SET_ERROR(error));
1158 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
1160 return (SET_ERROR(error));
1162 error = dnode_hold(os, ZVOL_OBJ, FTAG, &zv->zv_dn);
1164 return (SET_ERROR(error));
1166 set_capacity(zv->zv_disk, volsize >> 9);
1167 zv->zv_volsize = volsize;
1168 zv->zv_zilog = zil_open(os, zvol_get_data);
1170 if (ro || dmu_objset_is_snapshot(os) ||
1171 !spa_writeable(dmu_objset_spa(os))) {
1172 set_disk_ro(zv->zv_disk, 1);
1173 zv->zv_flags |= ZVOL_RDONLY;
1175 set_disk_ro(zv->zv_disk, 0);
1176 zv->zv_flags &= ~ZVOL_RDONLY;
1182 * Shutdown every zv_objset related stuff except zv_objset itself.
1183 * The is the reverse of zvol_setup_zv.
1186 zvol_shutdown_zv(zvol_state_t *zv)
1188 ASSERT(MUTEX_HELD(&zv->zv_state_lock) &&
1189 RW_LOCK_HELD(&zv->zv_suspend_lock));
1191 zil_close(zv->zv_zilog);
1192 zv->zv_zilog = NULL;
1194 dnode_rele(zv->zv_dn, FTAG);
1200 if (dsl_dataset_is_dirty(dmu_objset_ds(zv->zv_objset)) &&
1201 !(zv->zv_flags & ZVOL_RDONLY))
1202 txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1203 (void) dmu_objset_evict_dbufs(zv->zv_objset);
1207 * return the proper tag for rollback and recv
1210 zvol_tag(zvol_state_t *zv)
1212 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
1213 return (zv->zv_open_count > 0 ? zv : NULL);
1217 * Suspend the zvol for recv and rollback.
1220 zvol_suspend(const char *name)
1224 zv = zvol_find_by_name(name, RW_WRITER);
1229 /* block all I/O, release in zvol_resume. */
1230 ASSERT(MUTEX_HELD(&zv->zv_state_lock) &&
1231 RW_WRITE_HELD(&zv->zv_suspend_lock));
1233 atomic_inc(&zv->zv_suspend_ref);
1235 if (zv->zv_open_count > 0)
1236 zvol_shutdown_zv(zv);
1239 * do not hold zv_state_lock across suspend/resume to
1240 * avoid locking up zvol lookups
1242 mutex_exit(&zv->zv_state_lock);
1244 /* zv_suspend_lock is released in zvol_resume() */
1249 zvol_resume(zvol_state_t *zv)
1253 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
1255 mutex_enter(&zv->zv_state_lock);
1257 if (zv->zv_open_count > 0) {
1258 VERIFY0(dmu_objset_hold(zv->zv_name, zv, &zv->zv_objset));
1259 VERIFY3P(zv->zv_objset->os_dsl_dataset->ds_owner, ==, zv);
1260 VERIFY(dsl_dataset_long_held(zv->zv_objset->os_dsl_dataset));
1261 dmu_objset_rele(zv->zv_objset, zv);
1263 error = zvol_setup_zv(zv);
1266 mutex_exit(&zv->zv_state_lock);
1268 rw_exit(&zv->zv_suspend_lock);
1270 * We need this because we don't hold zvol_state_lock while releasing
1271 * zv_suspend_lock. zvol_remove_minors_impl thus cannot check
1272 * zv_suspend_lock to determine it is safe to free because rwlock is
1273 * not inherent atomic.
1275 atomic_dec(&zv->zv_suspend_ref);
1277 return (SET_ERROR(error));
1281 zvol_first_open(zvol_state_t *zv)
1284 int error, locked = 0;
1286 ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
1287 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1290 * In all other cases the spa_namespace_lock is taken before the
1291 * bdev->bd_mutex lock. But in this case the Linux __blkdev_get()
1292 * function calls fops->open() with the bdev->bd_mutex lock held.
1293 * This deadlock can be easily observed with zvols used as vdevs.
1295 * To avoid a potential lock inversion deadlock we preemptively
1296 * try to take the spa_namespace_lock(). Normally it will not
1297 * be contended and this is safe because spa_open_common() handles
1298 * the case where the caller already holds the spa_namespace_lock.
1300 * When it is contended we risk a lock inversion if we were to
1301 * block waiting for the lock. Luckily, the __blkdev_get()
1302 * function allows us to return -ERESTARTSYS which will result in
1303 * bdev->bd_mutex being dropped, reacquired, and fops->open() being
1304 * called again. This process can be repeated safely until both
1305 * locks are acquired.
1307 if (!mutex_owned(&spa_namespace_lock)) {
1308 locked = mutex_tryenter(&spa_namespace_lock);
1310 return (-SET_ERROR(ERESTARTSYS));
1313 /* lie and say we're read-only */
1314 error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, 1, zv, &os);
1320 error = zvol_setup_zv(zv);
1323 dmu_objset_disown(os, zv);
1324 zv->zv_objset = NULL;
1329 mutex_exit(&spa_namespace_lock);
1330 return (SET_ERROR(-error));
1334 zvol_last_close(zvol_state_t *zv)
1336 ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
1337 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1339 zvol_shutdown_zv(zv);
1341 dmu_objset_disown(zv->zv_objset, zv);
1342 zv->zv_objset = NULL;
1346 zvol_open(struct block_device *bdev, fmode_t flag)
1350 boolean_t drop_suspend = B_FALSE;
1352 ASSERT(!mutex_owned(&zvol_state_lock));
1354 mutex_enter(&zvol_state_lock);
1356 * Obtain a copy of private_data under the zvol_state_lock to make
1357 * sure that either the result of zvol free code path setting
1358 * bdev->bd_disk->private_data to NULL is observed, or zvol_free()
1359 * is not called on this zv because of the positive zv_open_count.
1361 zv = bdev->bd_disk->private_data;
1363 mutex_exit(&zvol_state_lock);
1364 return (SET_ERROR(-ENXIO));
1367 /* take zv_suspend_lock before zv_state_lock */
1368 rw_enter(&zv->zv_suspend_lock, RW_READER);
1370 mutex_enter(&zv->zv_state_lock);
1373 * make sure zvol is not suspended during first open
1374 * (hold zv_suspend_lock), otherwise, drop the lock
1376 if (zv->zv_open_count == 0) {
1377 drop_suspend = B_TRUE;
1379 rw_exit(&zv->zv_suspend_lock);
1382 mutex_exit(&zvol_state_lock);
1384 if (zv->zv_open_count == 0) {
1385 error = zvol_first_open(zv);
1390 if ((flag & FMODE_WRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
1392 goto out_open_count;
1395 zv->zv_open_count++;
1397 check_disk_change(bdev);
1400 if (zv->zv_open_count == 0)
1401 zvol_last_close(zv);
1403 mutex_exit(&zv->zv_state_lock);
1405 rw_exit(&zv->zv_suspend_lock);
1406 if (error == -ERESTARTSYS)
1409 return (SET_ERROR(error));
1412 #ifdef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
1417 zvol_release(struct gendisk *disk, fmode_t mode)
1420 boolean_t drop_suspend = B_FALSE;
1422 ASSERT(!mutex_owned(&zvol_state_lock));
1424 mutex_enter(&zvol_state_lock);
1425 zv = disk->private_data;
1426 ASSERT(zv && zv->zv_open_count > 0);
1428 /* take zv_suspend_lock before zv_state_lock */
1429 rw_enter(&zv->zv_suspend_lock, RW_READER);
1431 mutex_enter(&zv->zv_state_lock);
1432 mutex_exit(&zvol_state_lock);
1435 * make sure zvol is not suspended during last close
1436 * (hold zv_suspend_lock), otherwise, drop the lock
1438 if (zv->zv_open_count == 1)
1439 drop_suspend = B_TRUE;
1441 rw_exit(&zv->zv_suspend_lock);
1443 zv->zv_open_count--;
1444 if (zv->zv_open_count == 0)
1445 zvol_last_close(zv);
1447 mutex_exit(&zv->zv_state_lock);
1450 rw_exit(&zv->zv_suspend_lock);
1452 #ifndef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
1458 zvol_ioctl(struct block_device *bdev, fmode_t mode,
1459 unsigned int cmd, unsigned long arg)
1461 zvol_state_t *zv = bdev->bd_disk->private_data;
1464 ASSERT(zv && zv->zv_open_count > 0);
1469 invalidate_bdev(bdev);
1470 rw_enter(&zv->zv_suspend_lock, RW_READER);
1472 if (dsl_dataset_is_dirty(dmu_objset_ds(zv->zv_objset)) &&
1473 !(zv->zv_flags & ZVOL_RDONLY))
1474 txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1476 rw_exit(&zv->zv_suspend_lock);
1480 mutex_enter(&zv->zv_state_lock);
1481 error = copy_to_user((void *)arg, zv->zv_name, MAXNAMELEN);
1482 mutex_exit(&zv->zv_state_lock);
1490 return (SET_ERROR(error));
1493 #ifdef CONFIG_COMPAT
1495 zvol_compat_ioctl(struct block_device *bdev, fmode_t mode,
1496 unsigned cmd, unsigned long arg)
1498 return (zvol_ioctl(bdev, mode, cmd, arg));
1501 #define zvol_compat_ioctl NULL
1504 static int zvol_media_changed(struct gendisk *disk)
1506 zvol_state_t *zv = disk->private_data;
1508 ASSERT(zv && zv->zv_open_count > 0);
1510 return (zv->zv_changed);
1513 static int zvol_revalidate_disk(struct gendisk *disk)
1515 zvol_state_t *zv = disk->private_data;
1517 ASSERT(zv && zv->zv_open_count > 0);
1520 set_capacity(zv->zv_disk, zv->zv_volsize >> 9);
1526 * Provide a simple virtual geometry for legacy compatibility. For devices
1527 * smaller than 1 MiB a small head and sector count is used to allow very
1528 * tiny devices. For devices over 1 Mib a standard head and sector count
1529 * is used to keep the cylinders count reasonable.
1532 zvol_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1534 zvol_state_t *zv = bdev->bd_disk->private_data;
1537 ASSERT(zv && zv->zv_open_count > 0);
1539 sectors = get_capacity(zv->zv_disk);
1541 if (sectors > 2048) {
1550 geo->cylinders = sectors / (geo->heads * geo->sectors);
1555 static struct kobject *
1556 zvol_probe(dev_t dev, int *part, void *arg)
1559 struct kobject *kobj;
1561 zv = zvol_find_by_dev(dev);
1562 kobj = zv ? get_disk_and_module(zv->zv_disk) : NULL;
1563 ASSERT(zv == NULL || MUTEX_HELD(&zv->zv_state_lock));
1565 mutex_exit(&zv->zv_state_lock);
1570 #ifdef HAVE_BDEV_BLOCK_DEVICE_OPERATIONS
1571 static struct block_device_operations zvol_ops = {
1573 .release = zvol_release,
1574 .ioctl = zvol_ioctl,
1575 .compat_ioctl = zvol_compat_ioctl,
1576 .media_changed = zvol_media_changed,
1577 .revalidate_disk = zvol_revalidate_disk,
1578 .getgeo = zvol_getgeo,
1579 .owner = THIS_MODULE,
1582 #else /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1585 zvol_open_by_inode(struct inode *inode, struct file *file)
1587 return (zvol_open(inode->i_bdev, file->f_mode));
1591 zvol_release_by_inode(struct inode *inode, struct file *file)
1593 return (zvol_release(inode->i_bdev->bd_disk, file->f_mode));
1597 zvol_ioctl_by_inode(struct inode *inode, struct file *file,
1598 unsigned int cmd, unsigned long arg)
1600 if (file == NULL || inode == NULL)
1601 return (SET_ERROR(-EINVAL));
1603 return (zvol_ioctl(inode->i_bdev, file->f_mode, cmd, arg));
1606 #ifdef CONFIG_COMPAT
1608 zvol_compat_ioctl_by_inode(struct file *file,
1609 unsigned int cmd, unsigned long arg)
1612 return (SET_ERROR(-EINVAL));
1614 return (zvol_compat_ioctl(file->f_dentry->d_inode->i_bdev,
1615 file->f_mode, cmd, arg));
1618 #define zvol_compat_ioctl_by_inode NULL
1621 static struct block_device_operations zvol_ops = {
1622 .open = zvol_open_by_inode,
1623 .release = zvol_release_by_inode,
1624 .ioctl = zvol_ioctl_by_inode,
1625 .compat_ioctl = zvol_compat_ioctl_by_inode,
1626 .media_changed = zvol_media_changed,
1627 .revalidate_disk = zvol_revalidate_disk,
1628 .getgeo = zvol_getgeo,
1629 .owner = THIS_MODULE,
1631 #endif /* HAVE_BDEV_BLOCK_DEVICE_OPERATIONS */
1634 * Allocate memory for a new zvol_state_t and setup the required
1635 * request queue and generic disk structures for the block device.
1637 static zvol_state_t *
1638 zvol_alloc(dev_t dev, const char *name)
1643 if (dsl_prop_get_integer(name, "volmode", &volmode, NULL) != 0)
1646 if (volmode == ZFS_VOLMODE_DEFAULT)
1647 volmode = zvol_volmode;
1649 if (volmode == ZFS_VOLMODE_NONE)
1652 zv = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
1654 list_link_init(&zv->zv_next);
1656 mutex_init(&zv->zv_state_lock, NULL, MUTEX_DEFAULT, NULL);
1658 zv->zv_queue = blk_alloc_queue(GFP_ATOMIC);
1659 if (zv->zv_queue == NULL)
1662 blk_queue_make_request(zv->zv_queue, zvol_request);
1663 blk_queue_set_write_cache(zv->zv_queue, B_TRUE, B_TRUE);
1665 /* Limit read-ahead to a single page to prevent over-prefetching. */
1666 blk_queue_set_read_ahead(zv->zv_queue, 1);
1668 /* Disable write merging in favor of the ZIO pipeline. */
1669 queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, zv->zv_queue);
1671 zv->zv_disk = alloc_disk(ZVOL_MINORS);
1672 if (zv->zv_disk == NULL)
1675 zv->zv_queue->queuedata = zv;
1677 zv->zv_open_count = 0;
1678 strlcpy(zv->zv_name, name, MAXNAMELEN);
1680 zfs_rlock_init(&zv->zv_range_lock);
1681 rw_init(&zv->zv_suspend_lock, NULL, RW_DEFAULT, NULL);
1683 zv->zv_disk->major = zvol_major;
1684 if (volmode == ZFS_VOLMODE_DEV) {
1686 * ZFS_VOLMODE_DEV disable partitioning on ZVOL devices: set
1687 * gendisk->minors = 1 as noted in include/linux/genhd.h.
1688 * Also disable extended partition numbers (GENHD_FL_EXT_DEVT)
1689 * and suppresses partition scanning (GENHD_FL_NO_PART_SCAN)
1690 * setting gendisk->flags accordingly.
1692 zv->zv_disk->minors = 1;
1693 #if defined(GENHD_FL_EXT_DEVT)
1694 zv->zv_disk->flags &= ~GENHD_FL_EXT_DEVT;
1696 #if defined(GENHD_FL_NO_PART_SCAN)
1697 zv->zv_disk->flags |= GENHD_FL_NO_PART_SCAN;
1700 zv->zv_disk->first_minor = (dev & MINORMASK);
1701 zv->zv_disk->fops = &zvol_ops;
1702 zv->zv_disk->private_data = zv;
1703 zv->zv_disk->queue = zv->zv_queue;
1704 snprintf(zv->zv_disk->disk_name, DISK_NAME_LEN, "%s%d",
1705 ZVOL_DEV_NAME, (dev & MINORMASK));
1710 blk_cleanup_queue(zv->zv_queue);
1712 kmem_free(zv, sizeof (zvol_state_t));
1718 * Cleanup then free a zvol_state_t which was created by zvol_alloc().
1719 * At this time, the structure is not opened by anyone, is taken off
1720 * the zvol_state_list, and has its private data set to NULL.
1721 * The zvol_state_lock is dropped.
1724 zvol_free(void *arg)
1726 zvol_state_t *zv = arg;
1728 ASSERT(!MUTEX_HELD(&zvol_state_lock));
1729 ASSERT(!RW_LOCK_HELD(&zv->zv_suspend_lock));
1730 ASSERT(!MUTEX_HELD(&zv->zv_state_lock));
1731 ASSERT(zv->zv_open_count == 0);
1732 ASSERT(zv->zv_disk->private_data == NULL);
1734 rw_destroy(&zv->zv_suspend_lock);
1735 zfs_rlock_destroy(&zv->zv_range_lock);
1737 del_gendisk(zv->zv_disk);
1738 blk_cleanup_queue(zv->zv_queue);
1739 put_disk(zv->zv_disk);
1741 ida_simple_remove(&zvol_ida, MINOR(zv->zv_dev) >> ZVOL_MINOR_BITS);
1743 mutex_destroy(&zv->zv_state_lock);
1745 kmem_free(zv, sizeof (zvol_state_t));
1749 * Create a block device minor node and setup the linkage between it
1750 * and the specified volume. Once this function returns the block
1751 * device is live and ready for use.
1754 zvol_create_minor_impl(const char *name)
1758 dmu_object_info_t *doi;
1764 uint64_t hash = zvol_name_hash(name);
1766 if (zvol_inhibit_dev)
1769 idx = ida_simple_get(&zvol_ida, 0, 0, kmem_flags_convert(KM_SLEEP));
1771 return (SET_ERROR(-idx));
1772 minor = idx << ZVOL_MINOR_BITS;
1774 zv = zvol_find_by_name_hash(name, hash, RW_NONE);
1776 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1777 mutex_exit(&zv->zv_state_lock);
1778 ida_simple_remove(&zvol_ida, idx);
1779 return (SET_ERROR(EEXIST));
1782 doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
1784 error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, FTAG, &os);
1788 error = dmu_object_info(os, ZVOL_OBJ, doi);
1790 goto out_dmu_objset_disown;
1792 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
1794 goto out_dmu_objset_disown;
1796 zv = zvol_alloc(MKDEV(zvol_major, minor), name);
1798 error = SET_ERROR(EAGAIN);
1799 goto out_dmu_objset_disown;
1803 if (dmu_objset_is_snapshot(os))
1804 zv->zv_flags |= ZVOL_RDONLY;
1806 zv->zv_volblocksize = doi->doi_data_block_size;
1807 zv->zv_volsize = volsize;
1810 set_capacity(zv->zv_disk, zv->zv_volsize >> 9);
1812 blk_queue_max_hw_sectors(zv->zv_queue, (DMU_MAX_ACCESS / 4) >> 9);
1813 blk_queue_max_segments(zv->zv_queue, UINT16_MAX);
1814 blk_queue_max_segment_size(zv->zv_queue, UINT_MAX);
1815 blk_queue_physical_block_size(zv->zv_queue, zv->zv_volblocksize);
1816 blk_queue_io_opt(zv->zv_queue, zv->zv_volblocksize);
1817 blk_queue_max_discard_sectors(zv->zv_queue,
1818 (zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
1819 blk_queue_discard_granularity(zv->zv_queue, zv->zv_volblocksize);
1820 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, zv->zv_queue);
1821 #ifdef QUEUE_FLAG_NONROT
1822 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, zv->zv_queue);
1824 #ifdef QUEUE_FLAG_ADD_RANDOM
1825 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, zv->zv_queue);
1828 if (spa_writeable(dmu_objset_spa(os))) {
1829 if (zil_replay_disable)
1830 zil_destroy(dmu_objset_zil(os), B_FALSE);
1832 zil_replay(os, zv, zvol_replay_vector);
1836 * When udev detects the addition of the device it will immediately
1837 * invoke blkid(8) to determine the type of content on the device.
1838 * Prefetching the blocks commonly scanned by blkid(8) will speed
1841 len = MIN(MAX(zvol_prefetch_bytes, 0), SPA_MAXBLOCKSIZE);
1843 dmu_prefetch(os, ZVOL_OBJ, 0, 0, len, ZIO_PRIORITY_SYNC_READ);
1844 dmu_prefetch(os, ZVOL_OBJ, 0, volsize - len, len,
1845 ZIO_PRIORITY_SYNC_READ);
1848 zv->zv_objset = NULL;
1849 out_dmu_objset_disown:
1850 dmu_objset_disown(os, FTAG);
1852 kmem_free(doi, sizeof (dmu_object_info_t));
1855 mutex_enter(&zvol_state_lock);
1857 mutex_exit(&zvol_state_lock);
1858 add_disk(zv->zv_disk);
1860 ida_simple_remove(&zvol_ida, idx);
1863 return (SET_ERROR(error));
1867 * Rename a block device minor mode for the specified volume.
1870 zvol_rename_minor(zvol_state_t *zv, const char *newname)
1872 int readonly = get_disk_ro(zv->zv_disk);
1874 ASSERT(MUTEX_HELD(&zvol_state_lock));
1875 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1877 strlcpy(zv->zv_name, newname, sizeof (zv->zv_name));
1879 /* move to new hashtable entry */
1880 zv->zv_hash = zvol_name_hash(zv->zv_name);
1881 hlist_del(&zv->zv_hlink);
1882 hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));
1885 * The block device's read-only state is briefly changed causing
1886 * a KOBJ_CHANGE uevent to be issued. This ensures udev detects
1887 * the name change and fixes the symlinks. This does not change
1888 * ZVOL_RDONLY in zv->zv_flags so the actual read-only state never
1889 * changes. This would normally be done using kobject_uevent() but
1890 * that is a GPL-only symbol which is why we need this workaround.
1892 set_disk_ro(zv->zv_disk, !readonly);
1893 set_disk_ro(zv->zv_disk, readonly);
1896 typedef struct minors_job {
1906 * Prefetch zvol dnodes for the minors_job
1909 zvol_prefetch_minors_impl(void *arg)
1911 minors_job_t *job = arg;
1912 char *dsname = job->name;
1913 objset_t *os = NULL;
1915 job->error = dmu_objset_own(dsname, DMU_OST_ZVOL, B_TRUE, FTAG,
1917 if (job->error == 0) {
1918 dmu_prefetch(os, ZVOL_OBJ, 0, 0, 0, ZIO_PRIORITY_SYNC_READ);
1919 dmu_objset_disown(os, FTAG);
1924 * Mask errors to continue dmu_objset_find() traversal
1927 zvol_create_snap_minor_cb(const char *dsname, void *arg)
1929 minors_job_t *j = arg;
1930 list_t *minors_list = j->list;
1931 const char *name = j->name;
1933 ASSERT0(MUTEX_HELD(&spa_namespace_lock));
1935 /* skip the designated dataset */
1936 if (name && strcmp(dsname, name) == 0)
1939 /* at this point, the dsname should name a snapshot */
1940 if (strchr(dsname, '@') == 0) {
1941 dprintf("zvol_create_snap_minor_cb(): "
1942 "%s is not a shapshot name\n", dsname);
1945 char *n = strdup(dsname);
1949 job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP);
1951 job->list = minors_list;
1953 list_insert_tail(minors_list, job);
1954 /* don't care if dispatch fails, because job->error is 0 */
1955 taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job,
1963 * Mask errors to continue dmu_objset_find() traversal
1966 zvol_create_minors_cb(const char *dsname, void *arg)
1970 list_t *minors_list = arg;
1972 ASSERT0(MUTEX_HELD(&spa_namespace_lock));
1974 error = dsl_prop_get_integer(dsname, "snapdev", &snapdev, NULL);
1979 * Given the name and the 'snapdev' property, create device minor nodes
1980 * with the linkages to zvols/snapshots as needed.
1981 * If the name represents a zvol, create a minor node for the zvol, then
1982 * check if its snapshots are 'visible', and if so, iterate over the
1983 * snapshots and create device minor nodes for those.
1985 if (strchr(dsname, '@') == 0) {
1987 char *n = strdup(dsname);
1991 job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP);
1993 job->list = minors_list;
1995 list_insert_tail(minors_list, job);
1996 /* don't care if dispatch fails, because job->error is 0 */
1997 taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job,
2000 if (snapdev == ZFS_SNAPDEV_VISIBLE) {
2002 * traverse snapshots only, do not traverse children,
2003 * and skip the 'dsname'
2005 error = dmu_objset_find((char *)dsname,
2006 zvol_create_snap_minor_cb, (void *)job,
2010 dprintf("zvol_create_minors_cb(): %s is not a zvol name\n",
2018 * Create minors for the specified dataset, including children and snapshots.
2019 * Pay attention to the 'snapdev' property and iterate over the snapshots
2020 * only if they are 'visible'. This approach allows one to assure that the
2021 * snapshot metadata is read from disk only if it is needed.
2023 * The name can represent a dataset to be recursively scanned for zvols and
2024 * their snapshots, or a single zvol snapshot. If the name represents a
2025 * dataset, the scan is performed in two nested stages:
2026 * - scan the dataset for zvols, and
2027 * - for each zvol, create a minor node, then check if the zvol's snapshots
2028 * are 'visible', and only then iterate over the snapshots if needed
2030 * If the name represents a snapshot, a check is performed if the snapshot is
2031 * 'visible' (which also verifies that the parent is a zvol), and if so,
2032 * a minor node for that snapshot is created.
2035 zvol_create_minors_impl(const char *name)
2038 fstrans_cookie_t cookie;
2043 if (zvol_inhibit_dev)
2047 * This is the list for prefetch jobs. Whenever we found a match
2048 * during dmu_objset_find, we insert a minors_job to the list and do
2049 * taskq_dispatch to parallel prefetch zvol dnodes. Note we don't need
2050 * any lock because all list operation is done on the current thread.
2052 * We will use this list to do zvol_create_minor_impl after prefetch
2053 * so we don't have to traverse using dmu_objset_find again.
2055 list_create(&minors_list, sizeof (minors_job_t),
2056 offsetof(minors_job_t, link));
2058 parent = kmem_alloc(MAXPATHLEN, KM_SLEEP);
2059 (void) strlcpy(parent, name, MAXPATHLEN);
2061 if ((atp = strrchr(parent, '@')) != NULL) {
2065 error = dsl_prop_get_integer(parent, "snapdev",
2068 if (error == 0 && snapdev == ZFS_SNAPDEV_VISIBLE)
2069 error = zvol_create_minor_impl(name);
2071 cookie = spl_fstrans_mark();
2072 error = dmu_objset_find(parent, zvol_create_minors_cb,
2073 &minors_list, DS_FIND_CHILDREN);
2074 spl_fstrans_unmark(cookie);
2077 kmem_free(parent, MAXPATHLEN);
2078 taskq_wait_outstanding(system_taskq, 0);
2081 * Prefetch is completed, we can do zvol_create_minor_impl
2084 while ((job = list_head(&minors_list)) != NULL) {
2085 list_remove(&minors_list, job);
2087 zvol_create_minor_impl(job->name);
2089 kmem_free(job, sizeof (minors_job_t));
2092 list_destroy(&minors_list);
2094 return (SET_ERROR(error));
2098 * Remove minors for specified dataset including children and snapshots.
2101 zvol_remove_minors_impl(const char *name)
2103 zvol_state_t *zv, *zv_next;
2104 int namelen = ((name) ? strlen(name) : 0);
2105 taskqid_t t, tid = TASKQID_INVALID;
2108 if (zvol_inhibit_dev)
2111 list_create(&free_list, sizeof (zvol_state_t),
2112 offsetof(zvol_state_t, zv_next));
2114 mutex_enter(&zvol_state_lock);
2116 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
2117 zv_next = list_next(&zvol_state_list, zv);
2119 mutex_enter(&zv->zv_state_lock);
2120 if (name == NULL || strcmp(zv->zv_name, name) == 0 ||
2121 (strncmp(zv->zv_name, name, namelen) == 0 &&
2122 (zv->zv_name[namelen] == '/' ||
2123 zv->zv_name[namelen] == '@'))) {
2125 * By holding zv_state_lock here, we guarantee that no
2126 * one is currently using this zv
2129 /* If in use, leave alone */
2130 if (zv->zv_open_count > 0 ||
2131 atomic_read(&zv->zv_suspend_ref)) {
2132 mutex_exit(&zv->zv_state_lock);
2139 * clear this while holding zvol_state_lock so
2140 * zvol_open won't open it
2142 zv->zv_disk->private_data = NULL;
2144 /* Drop zv_state_lock before zvol_free() */
2145 mutex_exit(&zv->zv_state_lock);
2147 /* try parallel zv_free, if failed do it in place */
2148 t = taskq_dispatch(system_taskq, zvol_free, zv,
2150 if (t == TASKQID_INVALID)
2151 list_insert_head(&free_list, zv);
2155 mutex_exit(&zv->zv_state_lock);
2158 mutex_exit(&zvol_state_lock);
2161 * Drop zvol_state_lock before calling zvol_free()
2163 while ((zv = list_head(&free_list)) != NULL) {
2164 list_remove(&free_list, zv);
2168 if (tid != TASKQID_INVALID)
2169 taskq_wait_outstanding(system_taskq, tid);
2172 /* Remove minor for this specific volume only */
2174 zvol_remove_minor_impl(const char *name)
2176 zvol_state_t *zv = NULL, *zv_next;
2178 if (zvol_inhibit_dev)
2181 mutex_enter(&zvol_state_lock);
2183 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
2184 zv_next = list_next(&zvol_state_list, zv);
2186 mutex_enter(&zv->zv_state_lock);
2187 if (strcmp(zv->zv_name, name) == 0) {
2189 * By holding zv_state_lock here, we guarantee that no
2190 * one is currently using this zv
2193 /* If in use, leave alone */
2194 if (zv->zv_open_count > 0 ||
2195 atomic_read(&zv->zv_suspend_ref)) {
2196 mutex_exit(&zv->zv_state_lock);
2201 /* clear this so zvol_open won't open it */
2202 zv->zv_disk->private_data = NULL;
2204 mutex_exit(&zv->zv_state_lock);
2207 mutex_exit(&zv->zv_state_lock);
2211 /* Drop zvol_state_lock before calling zvol_free() */
2212 mutex_exit(&zvol_state_lock);
2219 * Rename minors for specified dataset including children and snapshots.
2222 zvol_rename_minors_impl(const char *oldname, const char *newname)
2224 zvol_state_t *zv, *zv_next;
2225 int oldnamelen, newnamelen;
2227 if (zvol_inhibit_dev)
2230 oldnamelen = strlen(oldname);
2231 newnamelen = strlen(newname);
2233 mutex_enter(&zvol_state_lock);
2235 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
2236 zv_next = list_next(&zvol_state_list, zv);
2238 mutex_enter(&zv->zv_state_lock);
2240 /* If in use, leave alone */
2241 if (zv->zv_open_count > 0) {
2242 mutex_exit(&zv->zv_state_lock);
2246 if (strcmp(zv->zv_name, oldname) == 0) {
2247 zvol_rename_minor(zv, newname);
2248 } else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 &&
2249 (zv->zv_name[oldnamelen] == '/' ||
2250 zv->zv_name[oldnamelen] == '@')) {
2251 char *name = kmem_asprintf("%s%c%s", newname,
2252 zv->zv_name[oldnamelen],
2253 zv->zv_name + oldnamelen + 1);
2254 zvol_rename_minor(zv, name);
2255 kmem_free(name, strlen(name + 1));
2258 mutex_exit(&zv->zv_state_lock);
2261 mutex_exit(&zvol_state_lock);
2264 typedef struct zvol_snapdev_cb_arg {
2266 } zvol_snapdev_cb_arg_t;
2269 zvol_set_snapdev_cb(const char *dsname, void *param)
2271 zvol_snapdev_cb_arg_t *arg = param;
2273 if (strchr(dsname, '@') == NULL)
2276 switch (arg->snapdev) {
2277 case ZFS_SNAPDEV_VISIBLE:
2278 (void) zvol_create_minor_impl(dsname);
2280 case ZFS_SNAPDEV_HIDDEN:
2281 (void) zvol_remove_minor_impl(dsname);
2289 zvol_set_snapdev_impl(char *name, uint64_t snapdev)
2291 zvol_snapdev_cb_arg_t arg = {snapdev};
2292 fstrans_cookie_t cookie = spl_fstrans_mark();
2294 * The zvol_set_snapdev_sync() sets snapdev appropriately
2295 * in the dataset hierarchy. Here, we only scan snapshots.
2297 dmu_objset_find(name, zvol_set_snapdev_cb, &arg, DS_FIND_SNAPSHOTS);
2298 spl_fstrans_unmark(cookie);
2301 typedef struct zvol_volmode_cb_arg {
2303 } zvol_volmode_cb_arg_t;
2306 zvol_set_volmode_impl(char *name, uint64_t volmode)
2308 fstrans_cookie_t cookie = spl_fstrans_mark();
2310 if (strchr(name, '@') != NULL)
2314 * It's unfortunate we need to remove minors before we create new ones:
2315 * this is necessary because our backing gendisk (zvol_state->zv_disk)
2316 * coule be different when we set, for instance, volmode from "geom"
2317 * to "dev" (or vice versa).
2318 * A possible optimization is to modify our consumers so we don't get
2319 * called when "volmode" does not change.
2322 case ZFS_VOLMODE_NONE:
2323 (void) zvol_remove_minor_impl(name);
2325 case ZFS_VOLMODE_GEOM:
2326 case ZFS_VOLMODE_DEV:
2327 (void) zvol_remove_minor_impl(name);
2328 (void) zvol_create_minor_impl(name);
2330 case ZFS_VOLMODE_DEFAULT:
2331 (void) zvol_remove_minor_impl(name);
2332 if (zvol_volmode == ZFS_VOLMODE_NONE)
2334 else /* if zvol_volmode is invalid defaults to "geom" */
2335 (void) zvol_create_minor_impl(name);
2339 spl_fstrans_unmark(cookie);
2342 static zvol_task_t *
2343 zvol_task_alloc(zvol_async_op_t op, const char *name1, const char *name2,
2349 /* Never allow tasks on hidden names. */
2350 if (name1[0] == '$')
2353 task = kmem_zalloc(sizeof (zvol_task_t), KM_SLEEP);
2355 task->value = value;
2356 delim = strchr(name1, '/');
2357 strlcpy(task->pool, name1, delim ? (delim - name1 + 1) : MAXNAMELEN);
2359 strlcpy(task->name1, name1, MAXNAMELEN);
2361 strlcpy(task->name2, name2, MAXNAMELEN);
2367 zvol_task_free(zvol_task_t *task)
2369 kmem_free(task, sizeof (zvol_task_t));
2373 * The worker thread function performed asynchronously.
2376 zvol_task_cb(void *param)
2378 zvol_task_t *task = (zvol_task_t *)param;
2381 case ZVOL_ASYNC_CREATE_MINORS:
2382 (void) zvol_create_minors_impl(task->name1);
2384 case ZVOL_ASYNC_REMOVE_MINORS:
2385 zvol_remove_minors_impl(task->name1);
2387 case ZVOL_ASYNC_RENAME_MINORS:
2388 zvol_rename_minors_impl(task->name1, task->name2);
2390 case ZVOL_ASYNC_SET_SNAPDEV:
2391 zvol_set_snapdev_impl(task->name1, task->value);
2393 case ZVOL_ASYNC_SET_VOLMODE:
2394 zvol_set_volmode_impl(task->name1, task->value);
2401 zvol_task_free(task);
2404 typedef struct zvol_set_prop_int_arg {
2405 const char *zsda_name;
2406 uint64_t zsda_value;
2407 zprop_source_t zsda_source;
2409 } zvol_set_prop_int_arg_t;
2412 * Sanity check the dataset for safe use by the sync task. No additional
2413 * conditions are imposed.
2416 zvol_set_snapdev_check(void *arg, dmu_tx_t *tx)
2418 zvol_set_prop_int_arg_t *zsda = arg;
2419 dsl_pool_t *dp = dmu_tx_pool(tx);
2423 error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL);
2427 dsl_dir_rele(dd, FTAG);
2434 zvol_set_snapdev_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
2436 char dsname[MAXNAMELEN];
2440 dsl_dataset_name(ds, dsname);
2441 if (dsl_prop_get_int_ds(ds, "snapdev", &snapdev) != 0)
2443 task = zvol_task_alloc(ZVOL_ASYNC_SET_SNAPDEV, dsname, NULL, snapdev);
2447 (void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb,
2453 * Traverse all child datasets and apply snapdev appropriately.
2454 * We call dsl_prop_set_sync_impl() here to set the value only on the toplevel
2455 * dataset and read the effective "snapdev" on every child in the callback
2456 * function: this is because the value is not guaranteed to be the same in the
2457 * whole dataset hierarchy.
2460 zvol_set_snapdev_sync(void *arg, dmu_tx_t *tx)
2462 zvol_set_prop_int_arg_t *zsda = arg;
2463 dsl_pool_t *dp = dmu_tx_pool(tx);
2468 VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL));
2471 error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds);
2473 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_SNAPDEV),
2474 zsda->zsda_source, sizeof (zsda->zsda_value), 1,
2475 &zsda->zsda_value, zsda->zsda_tx);
2476 dsl_dataset_rele(ds, FTAG);
2478 dmu_objset_find_dp(dp, dd->dd_object, zvol_set_snapdev_sync_cb,
2479 zsda, DS_FIND_CHILDREN);
2481 dsl_dir_rele(dd, FTAG);
2485 zvol_set_snapdev(const char *ddname, zprop_source_t source, uint64_t snapdev)
2487 zvol_set_prop_int_arg_t zsda;
2489 zsda.zsda_name = ddname;
2490 zsda.zsda_source = source;
2491 zsda.zsda_value = snapdev;
2493 return (dsl_sync_task(ddname, zvol_set_snapdev_check,
2494 zvol_set_snapdev_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE));
2498 * Sanity check the dataset for safe use by the sync task. No additional
2499 * conditions are imposed.
2502 zvol_set_volmode_check(void *arg, dmu_tx_t *tx)
2504 zvol_set_prop_int_arg_t *zsda = arg;
2505 dsl_pool_t *dp = dmu_tx_pool(tx);
2509 error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL);
2513 dsl_dir_rele(dd, FTAG);
2520 zvol_set_volmode_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
2522 char dsname[MAXNAMELEN];
2526 dsl_dataset_name(ds, dsname);
2527 if (dsl_prop_get_int_ds(ds, "volmode", &volmode) != 0)
2529 task = zvol_task_alloc(ZVOL_ASYNC_SET_VOLMODE, dsname, NULL, volmode);
2533 (void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb,
2539 * Traverse all child datasets and apply volmode appropriately.
2540 * We call dsl_prop_set_sync_impl() here to set the value only on the toplevel
2541 * dataset and read the effective "volmode" on every child in the callback
2542 * function: this is because the value is not guaranteed to be the same in the
2543 * whole dataset hierarchy.
2546 zvol_set_volmode_sync(void *arg, dmu_tx_t *tx)
2548 zvol_set_prop_int_arg_t *zsda = arg;
2549 dsl_pool_t *dp = dmu_tx_pool(tx);
2554 VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL));
2557 error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds);
2559 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_VOLMODE),
2560 zsda->zsda_source, sizeof (zsda->zsda_value), 1,
2561 &zsda->zsda_value, zsda->zsda_tx);
2562 dsl_dataset_rele(ds, FTAG);
2565 dmu_objset_find_dp(dp, dd->dd_object, zvol_set_volmode_sync_cb,
2566 zsda, DS_FIND_CHILDREN);
2568 dsl_dir_rele(dd, FTAG);
2572 zvol_set_volmode(const char *ddname, zprop_source_t source, uint64_t volmode)
2574 zvol_set_prop_int_arg_t zsda;
2576 zsda.zsda_name = ddname;
2577 zsda.zsda_source = source;
2578 zsda.zsda_value = volmode;
2580 return (dsl_sync_task(ddname, zvol_set_volmode_check,
2581 zvol_set_volmode_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE));
2585 zvol_create_minors(spa_t *spa, const char *name, boolean_t async)
2590 task = zvol_task_alloc(ZVOL_ASYNC_CREATE_MINORS, name, NULL, ~0ULL);
2594 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
2595 if ((async == B_FALSE) && (id != TASKQID_INVALID))
2596 taskq_wait_id(spa->spa_zvol_taskq, id);
2600 zvol_remove_minors(spa_t *spa, const char *name, boolean_t async)
2605 task = zvol_task_alloc(ZVOL_ASYNC_REMOVE_MINORS, name, NULL, ~0ULL);
2609 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
2610 if ((async == B_FALSE) && (id != TASKQID_INVALID))
2611 taskq_wait_id(spa->spa_zvol_taskq, id);
2615 zvol_rename_minors(spa_t *spa, const char *name1, const char *name2,
2621 task = zvol_task_alloc(ZVOL_ASYNC_RENAME_MINORS, name1, name2, ~0ULL);
2625 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
2626 if ((async == B_FALSE) && (id != TASKQID_INVALID))
2627 taskq_wait_id(spa->spa_zvol_taskq, id);
2633 int threads = MIN(MAX(zvol_threads, 1), 1024);
2636 list_create(&zvol_state_list, sizeof (zvol_state_t),
2637 offsetof(zvol_state_t, zv_next));
2638 mutex_init(&zvol_state_lock, NULL, MUTEX_DEFAULT, NULL);
2639 ida_init(&zvol_ida);
2641 zvol_taskq = taskq_create(ZVOL_DRIVER, threads, maxclsyspri,
2642 threads * 2, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
2643 if (zvol_taskq == NULL) {
2644 printk(KERN_INFO "ZFS: taskq_create() failed\n");
2649 zvol_htable = kmem_alloc(ZVOL_HT_SIZE * sizeof (struct hlist_head),
2655 for (i = 0; i < ZVOL_HT_SIZE; i++)
2656 INIT_HLIST_HEAD(&zvol_htable[i]);
2658 error = register_blkdev(zvol_major, ZVOL_DRIVER);
2660 printk(KERN_INFO "ZFS: register_blkdev() failed %d\n", error);
2664 blk_register_region(MKDEV(zvol_major, 0), 1UL << MINORBITS,
2665 THIS_MODULE, zvol_probe, NULL, NULL);
2670 kmem_free(zvol_htable, ZVOL_HT_SIZE * sizeof (struct hlist_head));
2672 taskq_destroy(zvol_taskq);
2674 ida_destroy(&zvol_ida);
2675 mutex_destroy(&zvol_state_lock);
2676 list_destroy(&zvol_state_list);
2678 return (SET_ERROR(error));
2684 zvol_remove_minors_impl(NULL);
2686 blk_unregister_region(MKDEV(zvol_major, 0), 1UL << MINORBITS);
2687 unregister_blkdev(zvol_major, ZVOL_DRIVER);
2688 kmem_free(zvol_htable, ZVOL_HT_SIZE * sizeof (struct hlist_head));
2690 taskq_destroy(zvol_taskq);
2691 list_destroy(&zvol_state_list);
2692 mutex_destroy(&zvol_state_lock);
2694 ida_destroy(&zvol_ida);
2698 module_param(zvol_inhibit_dev, uint, 0644);
2699 MODULE_PARM_DESC(zvol_inhibit_dev, "Do not create zvol device nodes");
2701 module_param(zvol_major, uint, 0444);
2702 MODULE_PARM_DESC(zvol_major, "Major number for zvol device");
2704 module_param(zvol_threads, uint, 0444);
2705 MODULE_PARM_DESC(zvol_threads, "Max number of threads to handle I/O requests");
2707 module_param(zvol_request_sync, uint, 0644);
2708 MODULE_PARM_DESC(zvol_request_sync, "Synchronously handle bio requests");
2710 module_param(zvol_max_discard_blocks, ulong, 0444);
2711 MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard");
2713 module_param(zvol_prefetch_bytes, uint, 0644);
2714 MODULE_PARM_DESC(zvol_prefetch_bytes, "Prefetch N bytes at zvol start+end");
2716 module_param(zvol_volmode, uint, 0644);
2717 MODULE_PARM_DESC(zvol_volmode, "Default volmode property value");