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, 2018 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.
77 #include <sys/dataset_kstats.h>
79 #include <sys/dmu_traverse.h>
80 #include <sys/dsl_dataset.h>
81 #include <sys/dsl_prop.h>
82 #include <sys/dsl_dir.h>
84 #include <sys/zfeature.h>
85 #include <sys/zil_impl.h>
86 #include <sys/dmu_tx.h>
88 #include <sys/zfs_rlock.h>
89 #include <sys/spa_impl.h>
92 #include <linux/blkdev_compat.h>
93 #include <linux/task_io_accounting_ops.h>
95 unsigned int zvol_inhibit_dev = 0;
96 unsigned int zvol_major = ZVOL_MAJOR;
97 unsigned int zvol_threads = 32;
98 unsigned int zvol_request_sync = 0;
99 unsigned int zvol_prefetch_bytes = (128 * 1024);
100 unsigned long zvol_max_discard_blocks = 16384;
101 unsigned int zvol_volmode = ZFS_VOLMODE_GEOM;
103 static taskq_t *zvol_taskq;
104 static krwlock_t zvol_state_lock;
105 static list_t zvol_state_list;
107 #define ZVOL_HT_SIZE 1024
108 static struct hlist_head *zvol_htable;
109 #define ZVOL_HT_HEAD(hash) (&zvol_htable[(hash) & (ZVOL_HT_SIZE-1)])
111 static struct ida zvol_ida;
114 * The in-core state of each volume.
117 char zv_name[MAXNAMELEN]; /* name */
118 uint64_t zv_volsize; /* advertised space */
119 uint64_t zv_volblocksize; /* volume block size */
120 objset_t *zv_objset; /* objset handle */
121 uint32_t zv_flags; /* ZVOL_* flags */
122 uint32_t zv_open_count; /* open counts */
123 uint32_t zv_changed; /* disk changed */
124 zilog_t *zv_zilog; /* ZIL handle */
125 rangelock_t zv_rangelock; /* for range locking */
126 dnode_t *zv_dn; /* dnode hold */
127 dev_t zv_dev; /* device id */
128 struct gendisk *zv_disk; /* generic disk */
129 struct request_queue *zv_queue; /* request queue */
130 dataset_kstats_t zv_kstat; /* zvol kstats */
131 list_node_t zv_next; /* next zvol_state_t linkage */
132 uint64_t zv_hash; /* name hash */
133 struct hlist_node zv_hlink; /* hash link */
134 kmutex_t zv_state_lock; /* protects zvol_state_t */
135 atomic_t zv_suspend_ref; /* refcount for suspend */
136 krwlock_t zv_suspend_lock; /* suspend lock */
140 ZVOL_ASYNC_CREATE_MINORS,
141 ZVOL_ASYNC_REMOVE_MINORS,
142 ZVOL_ASYNC_RENAME_MINORS,
143 ZVOL_ASYNC_SET_SNAPDEV,
144 ZVOL_ASYNC_SET_VOLMODE,
150 char pool[MAXNAMELEN];
151 char name1[MAXNAMELEN];
152 char name2[MAXNAMELEN];
153 zprop_source_t source;
157 #define ZVOL_RDONLY 0x1
160 zvol_name_hash(const char *name)
163 uint64_t crc = -1ULL;
164 uint8_t *p = (uint8_t *)name;
165 ASSERT(zfs_crc64_table[128] == ZFS_CRC64_POLY);
166 for (i = 0; i < MAXNAMELEN - 1 && *p; i++, p++) {
167 crc = (crc >> 8) ^ zfs_crc64_table[(crc ^ (*p)) & 0xFF];
173 * Find a zvol_state_t given the full major+minor dev_t. If found,
174 * return with zv_state_lock taken, otherwise, return (NULL) without
175 * taking zv_state_lock.
177 static zvol_state_t *
178 zvol_find_by_dev(dev_t dev)
182 rw_enter(&zvol_state_lock, RW_READER);
183 for (zv = list_head(&zvol_state_list); zv != NULL;
184 zv = list_next(&zvol_state_list, zv)) {
185 mutex_enter(&zv->zv_state_lock);
186 if (zv->zv_dev == dev) {
187 rw_exit(&zvol_state_lock);
190 mutex_exit(&zv->zv_state_lock);
192 rw_exit(&zvol_state_lock);
198 * Find a zvol_state_t given the name and hash generated by zvol_name_hash.
199 * If found, return with zv_suspend_lock and zv_state_lock taken, otherwise,
200 * return (NULL) without the taking locks. The zv_suspend_lock is always taken
201 * before zv_state_lock. The mode argument indicates the mode (including none)
202 * for zv_suspend_lock to be taken.
204 static zvol_state_t *
205 zvol_find_by_name_hash(const char *name, uint64_t hash, int mode)
208 struct hlist_node *p = NULL;
210 rw_enter(&zvol_state_lock, RW_READER);
211 hlist_for_each(p, ZVOL_HT_HEAD(hash)) {
212 zv = hlist_entry(p, zvol_state_t, zv_hlink);
213 mutex_enter(&zv->zv_state_lock);
214 if (zv->zv_hash == hash &&
215 strncmp(zv->zv_name, name, MAXNAMELEN) == 0) {
217 * this is the right zvol, take the locks in the
220 if (mode != RW_NONE &&
221 !rw_tryenter(&zv->zv_suspend_lock, mode)) {
222 mutex_exit(&zv->zv_state_lock);
223 rw_enter(&zv->zv_suspend_lock, mode);
224 mutex_enter(&zv->zv_state_lock);
226 * zvol cannot be renamed as we continue
227 * to hold zvol_state_lock
229 ASSERT(zv->zv_hash == hash &&
230 strncmp(zv->zv_name, name, MAXNAMELEN)
233 rw_exit(&zvol_state_lock);
236 mutex_exit(&zv->zv_state_lock);
238 rw_exit(&zvol_state_lock);
244 * Find a zvol_state_t given the name.
245 * If found, return with zv_suspend_lock and zv_state_lock taken, otherwise,
246 * return (NULL) without the taking locks. The zv_suspend_lock is always taken
247 * before zv_state_lock. The mode argument indicates the mode (including none)
248 * for zv_suspend_lock to be taken.
250 static zvol_state_t *
251 zvol_find_by_name(const char *name, int mode)
253 return (zvol_find_by_name_hash(name, zvol_name_hash(name), mode));
258 * Given a path, return TRUE if path is a ZVOL.
261 zvol_is_zvol(const char *device)
263 struct block_device *bdev;
266 bdev = vdev_lookup_bdev(device);
270 major = MAJOR(bdev->bd_dev);
273 if (major == zvol_major)
280 * ZFS_IOC_CREATE callback handles dmu zvol and zap object creation.
283 zvol_create_cb(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx)
285 zfs_creat_t *zct = arg;
286 nvlist_t *nvprops = zct->zct_props;
288 uint64_t volblocksize, volsize;
290 VERIFY(nvlist_lookup_uint64(nvprops,
291 zfs_prop_to_name(ZFS_PROP_VOLSIZE), &volsize) == 0);
292 if (nvlist_lookup_uint64(nvprops,
293 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE), &volblocksize) != 0)
294 volblocksize = zfs_prop_default_numeric(ZFS_PROP_VOLBLOCKSIZE);
297 * These properties must be removed from the list so the generic
298 * property setting step won't apply to them.
300 VERIFY(nvlist_remove_all(nvprops,
301 zfs_prop_to_name(ZFS_PROP_VOLSIZE)) == 0);
302 (void) nvlist_remove_all(nvprops,
303 zfs_prop_to_name(ZFS_PROP_VOLBLOCKSIZE));
305 error = dmu_object_claim(os, ZVOL_OBJ, DMU_OT_ZVOL, volblocksize,
309 error = zap_create_claim(os, ZVOL_ZAP_OBJ, DMU_OT_ZVOL_PROP,
313 error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize, tx);
318 * ZFS_IOC_OBJSET_STATS entry point.
321 zvol_get_stats(objset_t *os, nvlist_t *nv)
324 dmu_object_info_t *doi;
327 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &val);
329 return (SET_ERROR(error));
331 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLSIZE, val);
332 doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
333 error = dmu_object_info(os, ZVOL_OBJ, doi);
336 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_VOLBLOCKSIZE,
337 doi->doi_data_block_size);
340 kmem_free(doi, sizeof (dmu_object_info_t));
342 return (SET_ERROR(error));
346 * Sanity check volume size.
349 zvol_check_volsize(uint64_t volsize, uint64_t blocksize)
352 return (SET_ERROR(EINVAL));
354 if (volsize % blocksize != 0)
355 return (SET_ERROR(EINVAL));
358 if (volsize - 1 > SPEC_MAXOFFSET_T)
359 return (SET_ERROR(EOVERFLOW));
365 * Ensure the zap is flushed then inform the VFS of the capacity change.
368 zvol_update_volsize(uint64_t volsize, objset_t *os)
374 tx = dmu_tx_create(os);
375 dmu_tx_hold_zap(tx, ZVOL_ZAP_OBJ, TRUE, NULL);
376 dmu_tx_mark_netfree(tx);
377 error = dmu_tx_assign(tx, TXG_WAIT);
380 return (SET_ERROR(error));
382 txg = dmu_tx_get_txg(tx);
384 error = zap_update(os, ZVOL_ZAP_OBJ, "size", 8, 1,
388 txg_wait_synced(dmu_objset_pool(os), txg);
391 error = dmu_free_long_range(os,
392 ZVOL_OBJ, volsize, DMU_OBJECT_END);
398 * Set ZFS_PROP_VOLSIZE set entry point. Note that modifying the volume
399 * size will result in a udev "change" event being generated.
402 zvol_set_volsize(const char *name, uint64_t volsize)
405 struct gendisk *disk = NULL;
408 boolean_t owned = B_FALSE;
410 error = dsl_prop_get_integer(name,
411 zfs_prop_to_name(ZFS_PROP_READONLY), &readonly, NULL);
413 return (SET_ERROR(error));
415 return (SET_ERROR(EROFS));
417 zvol_state_t *zv = zvol_find_by_name(name, RW_READER);
419 ASSERT(zv == NULL || (MUTEX_HELD(&zv->zv_state_lock) &&
420 RW_READ_HELD(&zv->zv_suspend_lock)));
422 if (zv == NULL || zv->zv_objset == NULL) {
424 rw_exit(&zv->zv_suspend_lock);
425 if ((error = dmu_objset_own(name, DMU_OST_ZVOL, B_FALSE, B_TRUE,
428 mutex_exit(&zv->zv_state_lock);
429 return (SET_ERROR(error));
438 dmu_object_info_t *doi = kmem_alloc(sizeof (*doi), KM_SLEEP);
440 if ((error = dmu_object_info(os, ZVOL_OBJ, doi)) ||
441 (error = zvol_check_volsize(volsize, doi->doi_data_block_size)))
444 error = zvol_update_volsize(volsize, os);
445 if (error == 0 && zv != NULL) {
446 zv->zv_volsize = volsize;
451 kmem_free(doi, sizeof (dmu_object_info_t));
454 dmu_objset_disown(os, B_TRUE, FTAG);
456 zv->zv_objset = NULL;
458 rw_exit(&zv->zv_suspend_lock);
462 mutex_exit(&zv->zv_state_lock);
465 revalidate_disk(disk);
467 return (SET_ERROR(error));
471 * Sanity check volume block size.
474 zvol_check_volblocksize(const char *name, uint64_t volblocksize)
476 /* Record sizes above 128k need the feature to be enabled */
477 if (volblocksize > SPA_OLD_MAXBLOCKSIZE) {
481 if ((error = spa_open(name, &spa, FTAG)) != 0)
484 if (!spa_feature_is_enabled(spa, SPA_FEATURE_LARGE_BLOCKS)) {
485 spa_close(spa, FTAG);
486 return (SET_ERROR(ENOTSUP));
490 * We don't allow setting the property above 1MB,
491 * unless the tunable has been changed.
493 if (volblocksize > zfs_max_recordsize)
494 return (SET_ERROR(EDOM));
496 spa_close(spa, FTAG);
499 if (volblocksize < SPA_MINBLOCKSIZE ||
500 volblocksize > SPA_MAXBLOCKSIZE ||
502 return (SET_ERROR(EDOM));
508 * Set ZFS_PROP_VOLBLOCKSIZE set entry point.
511 zvol_set_volblocksize(const char *name, uint64_t volblocksize)
517 zv = zvol_find_by_name(name, RW_READER);
520 return (SET_ERROR(ENXIO));
522 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
523 ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
525 if (zv->zv_flags & ZVOL_RDONLY) {
526 mutex_exit(&zv->zv_state_lock);
527 rw_exit(&zv->zv_suspend_lock);
528 return (SET_ERROR(EROFS));
531 tx = dmu_tx_create(zv->zv_objset);
532 dmu_tx_hold_bonus(tx, ZVOL_OBJ);
533 error = dmu_tx_assign(tx, TXG_WAIT);
537 error = dmu_object_set_blocksize(zv->zv_objset, ZVOL_OBJ,
538 volblocksize, 0, tx);
539 if (error == ENOTSUP)
540 error = SET_ERROR(EBUSY);
543 zv->zv_volblocksize = volblocksize;
546 mutex_exit(&zv->zv_state_lock);
547 rw_exit(&zv->zv_suspend_lock);
549 return (SET_ERROR(error));
553 * Replay a TX_TRUNCATE ZIL transaction if asked. TX_TRUNCATE is how we
554 * implement DKIOCFREE/free-long-range.
557 zvol_replay_truncate(void *arg1, void *arg2, boolean_t byteswap)
559 zvol_state_t *zv = arg1;
560 lr_truncate_t *lr = arg2;
561 uint64_t offset, length;
564 byteswap_uint64_array(lr, sizeof (*lr));
566 offset = lr->lr_offset;
567 length = lr->lr_length;
569 return (dmu_free_long_range(zv->zv_objset, ZVOL_OBJ, offset, length));
573 * Replay a TX_WRITE ZIL transaction that didn't get committed
574 * after a system failure
577 zvol_replay_write(void *arg1, void *arg2, boolean_t byteswap)
579 zvol_state_t *zv = arg1;
580 lr_write_t *lr = arg2;
581 objset_t *os = zv->zv_objset;
582 char *data = (char *)(lr + 1); /* data follows lr_write_t */
583 uint64_t offset, length;
588 byteswap_uint64_array(lr, sizeof (*lr));
590 offset = lr->lr_offset;
591 length = lr->lr_length;
593 /* If it's a dmu_sync() block, write the whole block */
594 if (lr->lr_common.lrc_reclen == sizeof (lr_write_t)) {
595 uint64_t blocksize = BP_GET_LSIZE(&lr->lr_blkptr);
596 if (length < blocksize) {
597 offset -= offset % blocksize;
602 tx = dmu_tx_create(os);
603 dmu_tx_hold_write(tx, ZVOL_OBJ, offset, length);
604 error = dmu_tx_assign(tx, TXG_WAIT);
608 dmu_write(os, ZVOL_OBJ, offset, length, data, tx);
616 zvol_replay_err(void *arg1, void *arg2, boolean_t byteswap)
618 return (SET_ERROR(ENOTSUP));
622 * Callback vectors for replaying records.
623 * Only TX_WRITE and TX_TRUNCATE are needed for zvol.
625 zil_replay_func_t *zvol_replay_vector[TX_MAX_TYPE] = {
626 zvol_replay_err, /* no such transaction type */
627 zvol_replay_err, /* TX_CREATE */
628 zvol_replay_err, /* TX_MKDIR */
629 zvol_replay_err, /* TX_MKXATTR */
630 zvol_replay_err, /* TX_SYMLINK */
631 zvol_replay_err, /* TX_REMOVE */
632 zvol_replay_err, /* TX_RMDIR */
633 zvol_replay_err, /* TX_LINK */
634 zvol_replay_err, /* TX_RENAME */
635 zvol_replay_write, /* TX_WRITE */
636 zvol_replay_truncate, /* TX_TRUNCATE */
637 zvol_replay_err, /* TX_SETATTR */
638 zvol_replay_err, /* TX_ACL */
639 zvol_replay_err, /* TX_CREATE_ATTR */
640 zvol_replay_err, /* TX_CREATE_ACL_ATTR */
641 zvol_replay_err, /* TX_MKDIR_ACL */
642 zvol_replay_err, /* TX_MKDIR_ATTR */
643 zvol_replay_err, /* TX_MKDIR_ACL_ATTR */
644 zvol_replay_err, /* TX_WRITE2 */
648 * zvol_log_write() handles synchronous writes using TX_WRITE ZIL transactions.
650 * We store data in the log buffers if it's small enough.
651 * Otherwise we will later flush the data out via dmu_sync().
653 ssize_t zvol_immediate_write_sz = 32768;
656 zvol_log_write(zvol_state_t *zv, dmu_tx_t *tx, uint64_t offset,
657 uint64_t size, int sync)
659 uint32_t blocksize = zv->zv_volblocksize;
660 zilog_t *zilog = zv->zv_zilog;
661 itx_wr_state_t write_state;
663 if (zil_replaying(zilog, tx))
666 if (zilog->zl_logbias == ZFS_LOGBIAS_THROUGHPUT)
667 write_state = WR_INDIRECT;
668 else if (!spa_has_slogs(zilog->zl_spa) &&
669 size >= blocksize && blocksize > zvol_immediate_write_sz)
670 write_state = WR_INDIRECT;
672 write_state = WR_COPIED;
674 write_state = WR_NEED_COPY;
679 itx_wr_state_t wr_state = write_state;
682 if (wr_state == WR_COPIED && size > ZIL_MAX_COPIED_DATA)
683 wr_state = WR_NEED_COPY;
684 else if (wr_state == WR_INDIRECT)
685 len = MIN(blocksize - P2PHASE(offset, blocksize), size);
687 itx = zil_itx_create(TX_WRITE, sizeof (*lr) +
688 (wr_state == WR_COPIED ? len : 0));
689 lr = (lr_write_t *)&itx->itx_lr;
690 if (wr_state == WR_COPIED && dmu_read_by_dnode(zv->zv_dn,
691 offset, len, lr+1, DMU_READ_NO_PREFETCH) != 0) {
692 zil_itx_destroy(itx);
693 itx = zil_itx_create(TX_WRITE, sizeof (*lr));
694 lr = (lr_write_t *)&itx->itx_lr;
695 wr_state = WR_NEED_COPY;
698 itx->itx_wr_state = wr_state;
699 lr->lr_foid = ZVOL_OBJ;
700 lr->lr_offset = offset;
703 BP_ZERO(&lr->lr_blkptr);
705 itx->itx_private = zv;
706 itx->itx_sync = sync;
708 (void) zil_itx_assign(zilog, itx, tx);
715 typedef struct zv_request {
722 uio_from_bio(uio_t *uio, struct bio *bio)
724 uio->uio_bvec = &bio->bi_io_vec[BIO_BI_IDX(bio)];
725 uio->uio_skip = BIO_BI_SKIP(bio);
726 uio->uio_resid = BIO_BI_SIZE(bio);
727 uio->uio_iovcnt = bio->bi_vcnt - BIO_BI_IDX(bio);
728 uio->uio_loffset = BIO_BI_SECTOR(bio) << 9;
729 uio->uio_limit = MAXOFFSET_T;
730 uio->uio_segflg = UIO_BVEC;
734 zvol_write(void *arg)
738 zv_request_t *zvr = arg;
739 struct bio *bio = zvr->bio;
741 uio_from_bio(&uio, bio);
743 zvol_state_t *zv = zvr->zv;
744 ASSERT(zv && zv->zv_open_count > 0);
746 ssize_t start_resid = uio.uio_resid;
747 unsigned long start_jif = jiffies;
748 blk_generic_start_io_acct(zv->zv_queue, WRITE, bio_sectors(bio),
749 &zv->zv_disk->part0);
752 bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
754 uint64_t volsize = zv->zv_volsize;
755 while (uio.uio_resid > 0 && uio.uio_loffset < volsize) {
756 uint64_t bytes = MIN(uio.uio_resid, DMU_MAX_ACCESS >> 1);
757 uint64_t off = uio.uio_loffset;
758 dmu_tx_t *tx = dmu_tx_create(zv->zv_objset);
760 if (bytes > volsize - off) /* don't write past the end */
761 bytes = volsize - off;
763 dmu_tx_hold_write(tx, ZVOL_OBJ, off, bytes);
765 /* This will only fail for ENOSPC */
766 error = dmu_tx_assign(tx, TXG_WAIT);
771 error = dmu_write_uio_dnode(zv->zv_dn, &uio, bytes, tx);
773 zvol_log_write(zv, tx, off, bytes, sync);
780 rangelock_exit(zvr->lr);
782 int64_t nwritten = start_resid - uio.uio_resid;
783 dataset_kstats_update_write_kstats(&zv->zv_kstat, nwritten);
784 task_io_account_write(nwritten);
787 zil_commit(zv->zv_zilog, ZVOL_OBJ);
789 rw_exit(&zv->zv_suspend_lock);
790 blk_generic_end_io_acct(zv->zv_queue, WRITE, &zv->zv_disk->part0,
792 BIO_END_IO(bio, -error);
793 kmem_free(zvr, sizeof (zv_request_t));
797 * Log a DKIOCFREE/free-long-range to the ZIL with TX_TRUNCATE.
800 zvol_log_truncate(zvol_state_t *zv, dmu_tx_t *tx, uint64_t off, uint64_t len,
805 zilog_t *zilog = zv->zv_zilog;
807 if (zil_replaying(zilog, tx))
810 itx = zil_itx_create(TX_TRUNCATE, sizeof (*lr));
811 lr = (lr_truncate_t *)&itx->itx_lr;
812 lr->lr_foid = ZVOL_OBJ;
816 itx->itx_sync = sync;
817 zil_itx_assign(zilog, itx, tx);
821 zvol_discard(void *arg)
823 zv_request_t *zvr = arg;
824 struct bio *bio = zvr->bio;
825 zvol_state_t *zv = zvr->zv;
826 uint64_t start = BIO_BI_SECTOR(bio) << 9;
827 uint64_t size = BIO_BI_SIZE(bio);
828 uint64_t end = start + size;
832 unsigned long start_jif;
834 ASSERT(zv && zv->zv_open_count > 0);
837 blk_generic_start_io_acct(zv->zv_queue, WRITE, bio_sectors(bio),
838 &zv->zv_disk->part0);
840 sync = bio_is_fua(bio) || zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
842 if (end > zv->zv_volsize) {
843 error = SET_ERROR(EIO);
848 * Align the request to volume block boundaries when a secure erase is
849 * not required. This will prevent dnode_free_range() from zeroing out
850 * the unaligned parts which is slow (read-modify-write) and useless
851 * since we are not freeing any space by doing so.
853 if (!bio_is_secure_erase(bio)) {
854 start = P2ROUNDUP(start, zv->zv_volblocksize);
855 end = P2ALIGN(end, zv->zv_volblocksize);
862 tx = dmu_tx_create(zv->zv_objset);
863 dmu_tx_mark_netfree(tx);
864 error = dmu_tx_assign(tx, TXG_WAIT);
868 zvol_log_truncate(zv, tx, start, size, B_TRUE);
870 error = dmu_free_long_range(zv->zv_objset,
871 ZVOL_OBJ, start, size);
874 rangelock_exit(zvr->lr);
876 if (error == 0 && sync)
877 zil_commit(zv->zv_zilog, ZVOL_OBJ);
879 rw_exit(&zv->zv_suspend_lock);
880 blk_generic_end_io_acct(zv->zv_queue, WRITE, &zv->zv_disk->part0,
882 BIO_END_IO(bio, -error);
883 kmem_free(zvr, sizeof (zv_request_t));
891 zv_request_t *zvr = arg;
892 struct bio *bio = zvr->bio;
894 uio_from_bio(&uio, bio);
896 zvol_state_t *zv = zvr->zv;
897 ASSERT(zv && zv->zv_open_count > 0);
899 ssize_t start_resid = uio.uio_resid;
900 unsigned long start_jif = jiffies;
901 blk_generic_start_io_acct(zv->zv_queue, READ, bio_sectors(bio),
902 &zv->zv_disk->part0);
904 uint64_t volsize = zv->zv_volsize;
905 while (uio.uio_resid > 0 && uio.uio_loffset < volsize) {
906 uint64_t bytes = MIN(uio.uio_resid, DMU_MAX_ACCESS >> 1);
908 /* don't read past the end */
909 if (bytes > volsize - uio.uio_loffset)
910 bytes = volsize - uio.uio_loffset;
912 error = dmu_read_uio_dnode(zv->zv_dn, &uio, bytes);
914 /* convert checksum errors into IO errors */
916 error = SET_ERROR(EIO);
920 rangelock_exit(zvr->lr);
922 int64_t nread = start_resid - uio.uio_resid;
923 dataset_kstats_update_read_kstats(&zv->zv_kstat, nread);
924 task_io_account_read(nread);
926 rw_exit(&zv->zv_suspend_lock);
927 blk_generic_end_io_acct(zv->zv_queue, READ, &zv->zv_disk->part0,
929 BIO_END_IO(bio, -error);
930 kmem_free(zvr, sizeof (zv_request_t));
933 static MAKE_REQUEST_FN_RET
934 zvol_request(struct request_queue *q, struct bio *bio)
936 zvol_state_t *zv = q->queuedata;
937 fstrans_cookie_t cookie = spl_fstrans_mark();
938 uint64_t offset = BIO_BI_SECTOR(bio) << 9;
939 uint64_t size = BIO_BI_SIZE(bio);
940 int rw = bio_data_dir(bio);
943 if (bio_has_data(bio) && offset + size > zv->zv_volsize) {
945 "%s: bad access: offset=%llu, size=%lu\n",
946 zv->zv_disk->disk_name,
947 (long long unsigned)offset,
948 (long unsigned)size);
950 BIO_END_IO(bio, -SET_ERROR(EIO));
955 boolean_t need_sync = B_FALSE;
957 if (unlikely(zv->zv_flags & ZVOL_RDONLY)) {
958 BIO_END_IO(bio, -SET_ERROR(EROFS));
963 * To be released in the I/O function. See the comment on
964 * rangelock_enter() below.
966 rw_enter(&zv->zv_suspend_lock, RW_READER);
968 /* bio marked as FLUSH need to flush before write */
969 if (bio_is_flush(bio))
970 zil_commit(zv->zv_zilog, ZVOL_OBJ);
972 /* Some requests are just for flush and nothing else. */
974 rw_exit(&zv->zv_suspend_lock);
979 zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
984 * To be released in the I/O function. Since the I/O functions
985 * are asynchronous, we take it here synchronously to make
986 * sure overlapped I/Os are properly ordered.
988 zvr->lr = rangelock_enter(&zv->zv_rangelock, offset, size,
991 * Sync writes and discards execute zil_commit() which may need
992 * to take a RL_READER lock on the whole block being modified
993 * via its zillog->zl_get_data(): to avoid circular dependency
994 * issues with taskq threads execute these requests
995 * synchronously here in zvol_request().
997 need_sync = bio_is_fua(bio) ||
998 zv->zv_objset->os_sync == ZFS_SYNC_ALWAYS;
999 if (bio_is_discard(bio) || bio_is_secure_erase(bio)) {
1000 if (zvol_request_sync || need_sync ||
1001 taskq_dispatch(zvol_taskq, zvol_discard, zvr,
1002 TQ_SLEEP) == TASKQID_INVALID)
1005 if (zvol_request_sync || need_sync ||
1006 taskq_dispatch(zvol_taskq, zvol_write, zvr,
1007 TQ_SLEEP) == TASKQID_INVALID)
1012 * The SCST driver, and possibly others, may issue READ I/Os
1013 * with a length of zero bytes. These empty I/Os contain no
1014 * data and require no additional handling.
1021 zvr = kmem_alloc(sizeof (zv_request_t), KM_SLEEP);
1025 rw_enter(&zv->zv_suspend_lock, RW_READER);
1027 zvr->lr = rangelock_enter(&zv->zv_rangelock, offset, size,
1029 if (zvol_request_sync || taskq_dispatch(zvol_taskq,
1030 zvol_read, zvr, TQ_SLEEP) == TASKQID_INVALID)
1035 spl_fstrans_unmark(cookie);
1036 #ifdef HAVE_MAKE_REQUEST_FN_RET_INT
1038 #elif defined(HAVE_MAKE_REQUEST_FN_RET_QC)
1039 return (BLK_QC_T_NONE);
1045 zvol_get_done(zgd_t *zgd, int error)
1048 dmu_buf_rele(zgd->zgd_db, zgd);
1050 rangelock_exit(zgd->zgd_lr);
1052 kmem_free(zgd, sizeof (zgd_t));
1056 * Get data to generate a TX_WRITE intent log record.
1059 zvol_get_data(void *arg, lr_write_t *lr, char *buf, struct lwb *lwb, zio_t *zio)
1061 zvol_state_t *zv = arg;
1062 uint64_t offset = lr->lr_offset;
1063 uint64_t size = lr->lr_length;
1068 ASSERT3P(lwb, !=, NULL);
1069 ASSERT3P(zio, !=, NULL);
1070 ASSERT3U(size, !=, 0);
1072 zgd = (zgd_t *)kmem_zalloc(sizeof (zgd_t), KM_SLEEP);
1076 * Write records come in two flavors: immediate and indirect.
1077 * For small writes it's cheaper to store the data with the
1078 * log record (immediate); for large writes it's cheaper to
1079 * sync the data and get a pointer to it (indirect) so that
1080 * we don't have to write the data twice.
1082 if (buf != NULL) { /* immediate write */
1083 zgd->zgd_lr = rangelock_enter(&zv->zv_rangelock, offset, size,
1085 error = dmu_read_by_dnode(zv->zv_dn, offset, size, buf,
1086 DMU_READ_NO_PREFETCH);
1087 } else { /* indirect write */
1089 * Have to lock the whole block to ensure when it's written out
1090 * and its checksum is being calculated that no one can change
1091 * the data. Contrarily to zfs_get_data we need not re-check
1092 * blocksize after we get the lock because it cannot be changed.
1094 size = zv->zv_volblocksize;
1095 offset = P2ALIGN_TYPED(offset, size, uint64_t);
1096 zgd->zgd_lr = rangelock_enter(&zv->zv_rangelock, offset, size,
1098 error = dmu_buf_hold_by_dnode(zv->zv_dn, offset, zgd, &db,
1099 DMU_READ_NO_PREFETCH);
1101 blkptr_t *bp = &lr->lr_blkptr;
1107 ASSERT(db->db_offset == offset);
1108 ASSERT(db->db_size == size);
1110 error = dmu_sync(zio, lr->lr_common.lrc_txg,
1111 zvol_get_done, zgd);
1118 zvol_get_done(zgd, error);
1120 return (SET_ERROR(error));
1124 * The zvol_state_t's are inserted into zvol_state_list and zvol_htable.
1127 zvol_insert(zvol_state_t *zv)
1129 ASSERT(RW_WRITE_HELD(&zvol_state_lock));
1130 ASSERT3U(MINOR(zv->zv_dev) & ZVOL_MINOR_MASK, ==, 0);
1131 list_insert_head(&zvol_state_list, zv);
1132 hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));
1136 * Simply remove the zvol from to list of zvols.
1139 zvol_remove(zvol_state_t *zv)
1141 ASSERT(RW_WRITE_HELD(&zvol_state_lock));
1142 list_remove(&zvol_state_list, zv);
1143 hlist_del(&zv->zv_hlink);
1147 * Setup zv after we just own the zv->objset
1150 zvol_setup_zv(zvol_state_t *zv)
1155 objset_t *os = zv->zv_objset;
1157 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1158 ASSERT(RW_LOCK_HELD(&zv->zv_suspend_lock));
1160 error = dsl_prop_get_integer(zv->zv_name, "readonly", &ro, NULL);
1162 return (SET_ERROR(error));
1164 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
1166 return (SET_ERROR(error));
1168 error = dnode_hold(os, ZVOL_OBJ, FTAG, &zv->zv_dn);
1170 return (SET_ERROR(error));
1172 set_capacity(zv->zv_disk, volsize >> 9);
1173 zv->zv_volsize = volsize;
1174 zv->zv_zilog = zil_open(os, zvol_get_data);
1176 if (ro || dmu_objset_is_snapshot(os) ||
1177 !spa_writeable(dmu_objset_spa(os))) {
1178 set_disk_ro(zv->zv_disk, 1);
1179 zv->zv_flags |= ZVOL_RDONLY;
1181 set_disk_ro(zv->zv_disk, 0);
1182 zv->zv_flags &= ~ZVOL_RDONLY;
1188 * Shutdown every zv_objset related stuff except zv_objset itself.
1189 * The is the reverse of zvol_setup_zv.
1192 zvol_shutdown_zv(zvol_state_t *zv)
1194 ASSERT(MUTEX_HELD(&zv->zv_state_lock) &&
1195 RW_LOCK_HELD(&zv->zv_suspend_lock));
1197 zil_close(zv->zv_zilog);
1198 zv->zv_zilog = NULL;
1200 dnode_rele(zv->zv_dn, FTAG);
1204 * Evict cached data. We must write out any dirty data before
1205 * disowning the dataset.
1207 if (!(zv->zv_flags & ZVOL_RDONLY))
1208 txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1209 (void) dmu_objset_evict_dbufs(zv->zv_objset);
1213 * return the proper tag for rollback and recv
1216 zvol_tag(zvol_state_t *zv)
1218 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
1219 return (zv->zv_open_count > 0 ? zv : NULL);
1223 * Suspend the zvol for recv and rollback.
1226 zvol_suspend(const char *name)
1230 zv = zvol_find_by_name(name, RW_WRITER);
1235 /* block all I/O, release in zvol_resume. */
1236 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1237 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
1239 atomic_inc(&zv->zv_suspend_ref);
1241 if (zv->zv_open_count > 0)
1242 zvol_shutdown_zv(zv);
1245 * do not hold zv_state_lock across suspend/resume to
1246 * avoid locking up zvol lookups
1248 mutex_exit(&zv->zv_state_lock);
1250 /* zv_suspend_lock is released in zvol_resume() */
1255 zvol_resume(zvol_state_t *zv)
1259 ASSERT(RW_WRITE_HELD(&zv->zv_suspend_lock));
1261 mutex_enter(&zv->zv_state_lock);
1263 if (zv->zv_open_count > 0) {
1264 VERIFY0(dmu_objset_hold(zv->zv_name, zv, &zv->zv_objset));
1265 VERIFY3P(zv->zv_objset->os_dsl_dataset->ds_owner, ==, zv);
1266 VERIFY(dsl_dataset_long_held(zv->zv_objset->os_dsl_dataset));
1267 dmu_objset_rele(zv->zv_objset, zv);
1269 error = zvol_setup_zv(zv);
1272 mutex_exit(&zv->zv_state_lock);
1274 rw_exit(&zv->zv_suspend_lock);
1276 * We need this because we don't hold zvol_state_lock while releasing
1277 * zv_suspend_lock. zvol_remove_minors_impl thus cannot check
1278 * zv_suspend_lock to determine it is safe to free because rwlock is
1279 * not inherent atomic.
1281 atomic_dec(&zv->zv_suspend_ref);
1283 return (SET_ERROR(error));
1287 zvol_first_open(zvol_state_t *zv, boolean_t readonly)
1290 int error, locked = 0;
1293 ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
1294 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1297 * In all other cases the spa_namespace_lock is taken before the
1298 * bdev->bd_mutex lock. But in this case the Linux __blkdev_get()
1299 * function calls fops->open() with the bdev->bd_mutex lock held.
1300 * This deadlock can be easily observed with zvols used as vdevs.
1302 * To avoid a potential lock inversion deadlock we preemptively
1303 * try to take the spa_namespace_lock(). Normally it will not
1304 * be contended and this is safe because spa_open_common() handles
1305 * the case where the caller already holds the spa_namespace_lock.
1307 * When it is contended we risk a lock inversion if we were to
1308 * block waiting for the lock. Luckily, the __blkdev_get()
1309 * function allows us to return -ERESTARTSYS which will result in
1310 * bdev->bd_mutex being dropped, reacquired, and fops->open() being
1311 * called again. This process can be repeated safely until both
1312 * locks are acquired.
1314 if (!mutex_owned(&spa_namespace_lock)) {
1315 locked = mutex_tryenter(&spa_namespace_lock);
1317 return (-SET_ERROR(ERESTARTSYS));
1320 ro = (readonly || (strchr(zv->zv_name, '@') != NULL));
1321 error = dmu_objset_own(zv->zv_name, DMU_OST_ZVOL, ro, B_TRUE, zv, &os);
1327 error = zvol_setup_zv(zv);
1330 dmu_objset_disown(os, 1, zv);
1331 zv->zv_objset = NULL;
1336 mutex_exit(&spa_namespace_lock);
1337 return (SET_ERROR(-error));
1341 zvol_last_close(zvol_state_t *zv)
1343 ASSERT(RW_READ_HELD(&zv->zv_suspend_lock));
1344 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1346 zvol_shutdown_zv(zv);
1348 dmu_objset_disown(zv->zv_objset, 1, zv);
1349 zv->zv_objset = NULL;
1353 zvol_open(struct block_device *bdev, fmode_t flag)
1357 boolean_t drop_suspend = B_TRUE;
1359 rw_enter(&zvol_state_lock, RW_READER);
1361 * Obtain a copy of private_data under the zvol_state_lock to make
1362 * sure that either the result of zvol free code path setting
1363 * bdev->bd_disk->private_data to NULL is observed, or zvol_free()
1364 * is not called on this zv because of the positive zv_open_count.
1366 zv = bdev->bd_disk->private_data;
1368 rw_exit(&zvol_state_lock);
1369 return (SET_ERROR(-ENXIO));
1372 mutex_enter(&zv->zv_state_lock);
1374 * make sure zvol is not suspended during first open
1375 * (hold zv_suspend_lock) and respect proper lock acquisition
1376 * ordering - zv_suspend_lock before zv_state_lock
1378 if (zv->zv_open_count == 0) {
1379 if (!rw_tryenter(&zv->zv_suspend_lock, RW_READER)) {
1380 mutex_exit(&zv->zv_state_lock);
1381 rw_enter(&zv->zv_suspend_lock, RW_READER);
1382 mutex_enter(&zv->zv_state_lock);
1383 /* check to see if zv_suspend_lock is needed */
1384 if (zv->zv_open_count != 0) {
1385 rw_exit(&zv->zv_suspend_lock);
1386 drop_suspend = B_FALSE;
1390 drop_suspend = B_FALSE;
1392 rw_exit(&zvol_state_lock);
1394 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1395 ASSERT(zv->zv_open_count != 0 || RW_READ_HELD(&zv->zv_suspend_lock));
1397 if (zv->zv_open_count == 0) {
1398 error = zvol_first_open(zv, !(flag & FMODE_WRITE));
1403 if ((flag & FMODE_WRITE) && (zv->zv_flags & ZVOL_RDONLY)) {
1405 goto out_open_count;
1408 zv->zv_open_count++;
1410 mutex_exit(&zv->zv_state_lock);
1412 rw_exit(&zv->zv_suspend_lock);
1414 check_disk_change(bdev);
1419 if (zv->zv_open_count == 0)
1420 zvol_last_close(zv);
1423 mutex_exit(&zv->zv_state_lock);
1425 rw_exit(&zv->zv_suspend_lock);
1426 if (error == -ERESTARTSYS)
1429 return (SET_ERROR(error));
1432 #ifdef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
1437 zvol_release(struct gendisk *disk, fmode_t mode)
1440 boolean_t drop_suspend = B_TRUE;
1442 rw_enter(&zvol_state_lock, RW_READER);
1443 zv = disk->private_data;
1445 mutex_enter(&zv->zv_state_lock);
1446 ASSERT(zv->zv_open_count > 0);
1448 * make sure zvol is not suspended during last close
1449 * (hold zv_suspend_lock) and respect proper lock acquisition
1450 * ordering - zv_suspend_lock before zv_state_lock
1452 if (zv->zv_open_count == 1) {
1453 if (!rw_tryenter(&zv->zv_suspend_lock, RW_READER)) {
1454 mutex_exit(&zv->zv_state_lock);
1455 rw_enter(&zv->zv_suspend_lock, RW_READER);
1456 mutex_enter(&zv->zv_state_lock);
1457 /* check to see if zv_suspend_lock is needed */
1458 if (zv->zv_open_count != 1) {
1459 rw_exit(&zv->zv_suspend_lock);
1460 drop_suspend = B_FALSE;
1464 drop_suspend = B_FALSE;
1466 rw_exit(&zvol_state_lock);
1468 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1469 ASSERT(zv->zv_open_count != 1 || RW_READ_HELD(&zv->zv_suspend_lock));
1471 zv->zv_open_count--;
1472 if (zv->zv_open_count == 0)
1473 zvol_last_close(zv);
1475 mutex_exit(&zv->zv_state_lock);
1478 rw_exit(&zv->zv_suspend_lock);
1480 #ifndef HAVE_BLOCK_DEVICE_OPERATIONS_RELEASE_VOID
1486 zvol_ioctl(struct block_device *bdev, fmode_t mode,
1487 unsigned int cmd, unsigned long arg)
1489 zvol_state_t *zv = bdev->bd_disk->private_data;
1492 ASSERT3U(zv->zv_open_count, >, 0);
1497 invalidate_bdev(bdev);
1498 rw_enter(&zv->zv_suspend_lock, RW_READER);
1500 if (!(zv->zv_flags & ZVOL_RDONLY))
1501 txg_wait_synced(dmu_objset_pool(zv->zv_objset), 0);
1503 rw_exit(&zv->zv_suspend_lock);
1507 mutex_enter(&zv->zv_state_lock);
1508 error = copy_to_user((void *)arg, zv->zv_name, MAXNAMELEN);
1509 mutex_exit(&zv->zv_state_lock);
1517 return (SET_ERROR(error));
1520 #ifdef CONFIG_COMPAT
1522 zvol_compat_ioctl(struct block_device *bdev, fmode_t mode,
1523 unsigned cmd, unsigned long arg)
1525 return (zvol_ioctl(bdev, mode, cmd, arg));
1528 #define zvol_compat_ioctl NULL
1532 * Linux 2.6.38 preferred interface.
1534 #ifdef HAVE_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS
1536 zvol_check_events(struct gendisk *disk, unsigned int clearing)
1538 unsigned int mask = 0;
1540 rw_enter(&zvol_state_lock, RW_READER);
1542 zvol_state_t *zv = disk->private_data;
1544 mutex_enter(&zv->zv_state_lock);
1545 mask = zv->zv_changed ? DISK_EVENT_MEDIA_CHANGE : 0;
1547 mutex_exit(&zv->zv_state_lock);
1550 rw_exit(&zvol_state_lock);
1555 static int zvol_media_changed(struct gendisk *disk)
1559 rw_enter(&zvol_state_lock, RW_READER);
1561 zvol_state_t *zv = disk->private_data;
1563 mutex_enter(&zv->zv_state_lock);
1564 changed = zv->zv_changed;
1566 mutex_exit(&zv->zv_state_lock);
1569 rw_exit(&zvol_state_lock);
1575 static int zvol_revalidate_disk(struct gendisk *disk)
1577 rw_enter(&zvol_state_lock, RW_READER);
1579 zvol_state_t *zv = disk->private_data;
1581 mutex_enter(&zv->zv_state_lock);
1582 set_capacity(zv->zv_disk, zv->zv_volsize >> SECTOR_BITS);
1583 mutex_exit(&zv->zv_state_lock);
1586 rw_exit(&zvol_state_lock);
1592 * Provide a simple virtual geometry for legacy compatibility. For devices
1593 * smaller than 1 MiB a small head and sector count is used to allow very
1594 * tiny devices. For devices over 1 Mib a standard head and sector count
1595 * is used to keep the cylinders count reasonable.
1598 zvol_getgeo(struct block_device *bdev, struct hd_geometry *geo)
1600 zvol_state_t *zv = bdev->bd_disk->private_data;
1603 ASSERT3U(zv->zv_open_count, >, 0);
1605 sectors = get_capacity(zv->zv_disk);
1607 if (sectors > 2048) {
1616 geo->cylinders = sectors / (geo->heads * geo->sectors);
1621 static struct kobject *
1622 zvol_probe(dev_t dev, int *part, void *arg)
1625 struct kobject *kobj;
1627 zv = zvol_find_by_dev(dev);
1628 kobj = zv ? get_disk_and_module(zv->zv_disk) : NULL;
1629 ASSERT(zv == NULL || MUTEX_HELD(&zv->zv_state_lock));
1631 mutex_exit(&zv->zv_state_lock);
1636 static struct block_device_operations zvol_ops = {
1638 .release = zvol_release,
1639 .ioctl = zvol_ioctl,
1640 .compat_ioctl = zvol_compat_ioctl,
1641 #ifdef HAVE_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS
1642 .check_events = zvol_check_events,
1644 .media_changed = zvol_media_changed,
1646 .revalidate_disk = zvol_revalidate_disk,
1647 .getgeo = zvol_getgeo,
1648 .owner = THIS_MODULE,
1652 * Allocate memory for a new zvol_state_t and setup the required
1653 * request queue and generic disk structures for the block device.
1655 static zvol_state_t *
1656 zvol_alloc(dev_t dev, const char *name)
1661 if (dsl_prop_get_integer(name, "volmode", &volmode, NULL) != 0)
1664 if (volmode == ZFS_VOLMODE_DEFAULT)
1665 volmode = zvol_volmode;
1667 if (volmode == ZFS_VOLMODE_NONE)
1670 zv = kmem_zalloc(sizeof (zvol_state_t), KM_SLEEP);
1672 list_link_init(&zv->zv_next);
1674 mutex_init(&zv->zv_state_lock, NULL, MUTEX_DEFAULT, NULL);
1676 zv->zv_queue = blk_alloc_queue(GFP_ATOMIC);
1677 if (zv->zv_queue == NULL)
1680 blk_queue_make_request(zv->zv_queue, zvol_request);
1681 blk_queue_set_write_cache(zv->zv_queue, B_TRUE, B_TRUE);
1683 /* Limit read-ahead to a single page to prevent over-prefetching. */
1684 blk_queue_set_read_ahead(zv->zv_queue, 1);
1686 /* Disable write merging in favor of the ZIO pipeline. */
1687 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, zv->zv_queue);
1689 zv->zv_disk = alloc_disk(ZVOL_MINORS);
1690 if (zv->zv_disk == NULL)
1693 zv->zv_queue->queuedata = zv;
1695 zv->zv_open_count = 0;
1696 strlcpy(zv->zv_name, name, MAXNAMELEN);
1698 rangelock_init(&zv->zv_rangelock, NULL, NULL);
1699 rw_init(&zv->zv_suspend_lock, NULL, RW_DEFAULT, NULL);
1701 zv->zv_disk->major = zvol_major;
1702 #ifdef HAVE_BLOCK_DEVICE_OPERATIONS_CHECK_EVENTS
1703 zv->zv_disk->events = DISK_EVENT_MEDIA_CHANGE;
1706 if (volmode == ZFS_VOLMODE_DEV) {
1708 * ZFS_VOLMODE_DEV disable partitioning on ZVOL devices: set
1709 * gendisk->minors = 1 as noted in include/linux/genhd.h.
1710 * Also disable extended partition numbers (GENHD_FL_EXT_DEVT)
1711 * and suppresses partition scanning (GENHD_FL_NO_PART_SCAN)
1712 * setting gendisk->flags accordingly.
1714 zv->zv_disk->minors = 1;
1715 #if defined(GENHD_FL_EXT_DEVT)
1716 zv->zv_disk->flags &= ~GENHD_FL_EXT_DEVT;
1718 #if defined(GENHD_FL_NO_PART_SCAN)
1719 zv->zv_disk->flags |= GENHD_FL_NO_PART_SCAN;
1722 zv->zv_disk->first_minor = (dev & MINORMASK);
1723 zv->zv_disk->fops = &zvol_ops;
1724 zv->zv_disk->private_data = zv;
1725 zv->zv_disk->queue = zv->zv_queue;
1726 snprintf(zv->zv_disk->disk_name, DISK_NAME_LEN, "%s%d",
1727 ZVOL_DEV_NAME, (dev & MINORMASK));
1732 blk_cleanup_queue(zv->zv_queue);
1734 kmem_free(zv, sizeof (zvol_state_t));
1740 * Cleanup then free a zvol_state_t which was created by zvol_alloc().
1741 * At this time, the structure is not opened by anyone, is taken off
1742 * the zvol_state_list, and has its private data set to NULL.
1743 * The zvol_state_lock is dropped.
1746 zvol_free(void *arg)
1748 zvol_state_t *zv = arg;
1750 ASSERT(!RW_LOCK_HELD(&zv->zv_suspend_lock));
1751 ASSERT(!MUTEX_HELD(&zv->zv_state_lock));
1752 ASSERT(zv->zv_open_count == 0);
1753 ASSERT(zv->zv_disk->private_data == NULL);
1755 rw_destroy(&zv->zv_suspend_lock);
1756 rangelock_fini(&zv->zv_rangelock);
1758 del_gendisk(zv->zv_disk);
1759 blk_cleanup_queue(zv->zv_queue);
1760 put_disk(zv->zv_disk);
1762 ida_simple_remove(&zvol_ida, MINOR(zv->zv_dev) >> ZVOL_MINOR_BITS);
1764 mutex_destroy(&zv->zv_state_lock);
1765 dataset_kstats_destroy(&zv->zv_kstat);
1767 kmem_free(zv, sizeof (zvol_state_t));
1771 * Create a block device minor node and setup the linkage between it
1772 * and the specified volume. Once this function returns the block
1773 * device is live and ready for use.
1776 zvol_create_minor_impl(const char *name)
1780 dmu_object_info_t *doi;
1786 uint64_t hash = zvol_name_hash(name);
1788 if (zvol_inhibit_dev)
1791 idx = ida_simple_get(&zvol_ida, 0, 0, kmem_flags_convert(KM_SLEEP));
1793 return (SET_ERROR(-idx));
1794 minor = idx << ZVOL_MINOR_BITS;
1796 zv = zvol_find_by_name_hash(name, hash, RW_NONE);
1798 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1799 mutex_exit(&zv->zv_state_lock);
1800 ida_simple_remove(&zvol_ida, idx);
1801 return (SET_ERROR(EEXIST));
1804 doi = kmem_alloc(sizeof (dmu_object_info_t), KM_SLEEP);
1806 error = dmu_objset_own(name, DMU_OST_ZVOL, B_TRUE, B_TRUE, FTAG, &os);
1810 error = dmu_object_info(os, ZVOL_OBJ, doi);
1812 goto out_dmu_objset_disown;
1814 error = zap_lookup(os, ZVOL_ZAP_OBJ, "size", 8, 1, &volsize);
1816 goto out_dmu_objset_disown;
1818 zv = zvol_alloc(MKDEV(zvol_major, minor), name);
1820 error = SET_ERROR(EAGAIN);
1821 goto out_dmu_objset_disown;
1825 if (dmu_objset_is_snapshot(os))
1826 zv->zv_flags |= ZVOL_RDONLY;
1828 zv->zv_volblocksize = doi->doi_data_block_size;
1829 zv->zv_volsize = volsize;
1832 set_capacity(zv->zv_disk, zv->zv_volsize >> 9);
1834 blk_queue_max_hw_sectors(zv->zv_queue, (DMU_MAX_ACCESS / 4) >> 9);
1835 blk_queue_max_segments(zv->zv_queue, UINT16_MAX);
1836 blk_queue_max_segment_size(zv->zv_queue, UINT_MAX);
1837 blk_queue_physical_block_size(zv->zv_queue, zv->zv_volblocksize);
1838 blk_queue_io_opt(zv->zv_queue, zv->zv_volblocksize);
1839 blk_queue_max_discard_sectors(zv->zv_queue,
1840 (zvol_max_discard_blocks * zv->zv_volblocksize) >> 9);
1841 blk_queue_discard_granularity(zv->zv_queue, zv->zv_volblocksize);
1842 blk_queue_flag_set(QUEUE_FLAG_DISCARD, zv->zv_queue);
1843 #ifdef QUEUE_FLAG_NONROT
1844 blk_queue_flag_set(QUEUE_FLAG_NONROT, zv->zv_queue);
1846 #ifdef QUEUE_FLAG_ADD_RANDOM
1847 blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, zv->zv_queue);
1850 if (spa_writeable(dmu_objset_spa(os))) {
1851 if (zil_replay_disable)
1852 zil_destroy(dmu_objset_zil(os), B_FALSE);
1854 zil_replay(os, zv, zvol_replay_vector);
1856 ASSERT3P(zv->zv_kstat.dk_kstats, ==, NULL);
1857 dataset_kstats_create(&zv->zv_kstat, zv->zv_objset);
1860 * When udev detects the addition of the device it will immediately
1861 * invoke blkid(8) to determine the type of content on the device.
1862 * Prefetching the blocks commonly scanned by blkid(8) will speed
1865 len = MIN(MAX(zvol_prefetch_bytes, 0), SPA_MAXBLOCKSIZE);
1867 dmu_prefetch(os, ZVOL_OBJ, 0, 0, len, ZIO_PRIORITY_SYNC_READ);
1868 dmu_prefetch(os, ZVOL_OBJ, 0, volsize - len, len,
1869 ZIO_PRIORITY_SYNC_READ);
1872 zv->zv_objset = NULL;
1873 out_dmu_objset_disown:
1874 dmu_objset_disown(os, B_TRUE, FTAG);
1876 kmem_free(doi, sizeof (dmu_object_info_t));
1879 rw_enter(&zvol_state_lock, RW_WRITER);
1881 rw_exit(&zvol_state_lock);
1882 add_disk(zv->zv_disk);
1884 ida_simple_remove(&zvol_ida, idx);
1887 return (SET_ERROR(error));
1891 * Rename a block device minor mode for the specified volume.
1894 zvol_rename_minor(zvol_state_t *zv, const char *newname)
1896 int readonly = get_disk_ro(zv->zv_disk);
1898 ASSERT(RW_LOCK_HELD(&zvol_state_lock));
1899 ASSERT(MUTEX_HELD(&zv->zv_state_lock));
1901 strlcpy(zv->zv_name, newname, sizeof (zv->zv_name));
1903 /* move to new hashtable entry */
1904 zv->zv_hash = zvol_name_hash(zv->zv_name);
1905 hlist_del(&zv->zv_hlink);
1906 hlist_add_head(&zv->zv_hlink, ZVOL_HT_HEAD(zv->zv_hash));
1909 * The block device's read-only state is briefly changed causing
1910 * a KOBJ_CHANGE uevent to be issued. This ensures udev detects
1911 * the name change and fixes the symlinks. This does not change
1912 * ZVOL_RDONLY in zv->zv_flags so the actual read-only state never
1913 * changes. This would normally be done using kobject_uevent() but
1914 * that is a GPL-only symbol which is why we need this workaround.
1916 set_disk_ro(zv->zv_disk, !readonly);
1917 set_disk_ro(zv->zv_disk, readonly);
1920 typedef struct minors_job {
1930 * Prefetch zvol dnodes for the minors_job
1933 zvol_prefetch_minors_impl(void *arg)
1935 minors_job_t *job = arg;
1936 char *dsname = job->name;
1937 objset_t *os = NULL;
1939 job->error = dmu_objset_own(dsname, DMU_OST_ZVOL, B_TRUE, B_TRUE,
1941 if (job->error == 0) {
1942 dmu_prefetch(os, ZVOL_OBJ, 0, 0, 0, ZIO_PRIORITY_SYNC_READ);
1943 dmu_objset_disown(os, B_TRUE, FTAG);
1948 * Mask errors to continue dmu_objset_find() traversal
1951 zvol_create_snap_minor_cb(const char *dsname, void *arg)
1953 minors_job_t *j = arg;
1954 list_t *minors_list = j->list;
1955 const char *name = j->name;
1957 ASSERT0(MUTEX_HELD(&spa_namespace_lock));
1959 /* skip the designated dataset */
1960 if (name && strcmp(dsname, name) == 0)
1963 /* at this point, the dsname should name a snapshot */
1964 if (strchr(dsname, '@') == 0) {
1965 dprintf("zvol_create_snap_minor_cb(): "
1966 "%s is not a shapshot name\n", dsname);
1969 char *n = strdup(dsname);
1973 job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP);
1975 job->list = minors_list;
1977 list_insert_tail(minors_list, job);
1978 /* don't care if dispatch fails, because job->error is 0 */
1979 taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job,
1987 * Mask errors to continue dmu_objset_find() traversal
1990 zvol_create_minors_cb(const char *dsname, void *arg)
1994 list_t *minors_list = arg;
1996 ASSERT0(MUTEX_HELD(&spa_namespace_lock));
1998 error = dsl_prop_get_integer(dsname, "snapdev", &snapdev, NULL);
2003 * Given the name and the 'snapdev' property, create device minor nodes
2004 * with the linkages to zvols/snapshots as needed.
2005 * If the name represents a zvol, create a minor node for the zvol, then
2006 * check if its snapshots are 'visible', and if so, iterate over the
2007 * snapshots and create device minor nodes for those.
2009 if (strchr(dsname, '@') == 0) {
2011 char *n = strdup(dsname);
2015 job = kmem_alloc(sizeof (minors_job_t), KM_SLEEP);
2017 job->list = minors_list;
2019 list_insert_tail(minors_list, job);
2020 /* don't care if dispatch fails, because job->error is 0 */
2021 taskq_dispatch(system_taskq, zvol_prefetch_minors_impl, job,
2024 if (snapdev == ZFS_SNAPDEV_VISIBLE) {
2026 * traverse snapshots only, do not traverse children,
2027 * and skip the 'dsname'
2029 error = dmu_objset_find((char *)dsname,
2030 zvol_create_snap_minor_cb, (void *)job,
2034 dprintf("zvol_create_minors_cb(): %s is not a zvol name\n",
2042 * Create minors for the specified dataset, including children and snapshots.
2043 * Pay attention to the 'snapdev' property and iterate over the snapshots
2044 * only if they are 'visible'. This approach allows one to assure that the
2045 * snapshot metadata is read from disk only if it is needed.
2047 * The name can represent a dataset to be recursively scanned for zvols and
2048 * their snapshots, or a single zvol snapshot. If the name represents a
2049 * dataset, the scan is performed in two nested stages:
2050 * - scan the dataset for zvols, and
2051 * - for each zvol, create a minor node, then check if the zvol's snapshots
2052 * are 'visible', and only then iterate over the snapshots if needed
2054 * If the name represents a snapshot, a check is performed if the snapshot is
2055 * 'visible' (which also verifies that the parent is a zvol), and if so,
2056 * a minor node for that snapshot is created.
2059 zvol_create_minors_impl(const char *name)
2062 fstrans_cookie_t cookie;
2067 if (zvol_inhibit_dev)
2071 * This is the list for prefetch jobs. Whenever we found a match
2072 * during dmu_objset_find, we insert a minors_job to the list and do
2073 * taskq_dispatch to parallel prefetch zvol dnodes. Note we don't need
2074 * any lock because all list operation is done on the current thread.
2076 * We will use this list to do zvol_create_minor_impl after prefetch
2077 * so we don't have to traverse using dmu_objset_find again.
2079 list_create(&minors_list, sizeof (minors_job_t),
2080 offsetof(minors_job_t, link));
2082 parent = kmem_alloc(MAXPATHLEN, KM_SLEEP);
2083 (void) strlcpy(parent, name, MAXPATHLEN);
2085 if ((atp = strrchr(parent, '@')) != NULL) {
2089 error = dsl_prop_get_integer(parent, "snapdev",
2092 if (error == 0 && snapdev == ZFS_SNAPDEV_VISIBLE)
2093 error = zvol_create_minor_impl(name);
2095 cookie = spl_fstrans_mark();
2096 error = dmu_objset_find(parent, zvol_create_minors_cb,
2097 &minors_list, DS_FIND_CHILDREN);
2098 spl_fstrans_unmark(cookie);
2101 kmem_free(parent, MAXPATHLEN);
2102 taskq_wait_outstanding(system_taskq, 0);
2105 * Prefetch is completed, we can do zvol_create_minor_impl
2108 while ((job = list_head(&minors_list)) != NULL) {
2109 list_remove(&minors_list, job);
2111 zvol_create_minor_impl(job->name);
2113 kmem_free(job, sizeof (minors_job_t));
2116 list_destroy(&minors_list);
2118 return (SET_ERROR(error));
2122 * Remove minors for specified dataset including children and snapshots.
2125 zvol_remove_minors_impl(const char *name)
2127 zvol_state_t *zv, *zv_next;
2128 int namelen = ((name) ? strlen(name) : 0);
2129 taskqid_t t, tid = TASKQID_INVALID;
2132 if (zvol_inhibit_dev)
2135 list_create(&free_list, sizeof (zvol_state_t),
2136 offsetof(zvol_state_t, zv_next));
2138 rw_enter(&zvol_state_lock, RW_WRITER);
2140 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
2141 zv_next = list_next(&zvol_state_list, zv);
2143 mutex_enter(&zv->zv_state_lock);
2144 if (name == NULL || strcmp(zv->zv_name, name) == 0 ||
2145 (strncmp(zv->zv_name, name, namelen) == 0 &&
2146 (zv->zv_name[namelen] == '/' ||
2147 zv->zv_name[namelen] == '@'))) {
2149 * By holding zv_state_lock here, we guarantee that no
2150 * one is currently using this zv
2153 /* If in use, leave alone */
2154 if (zv->zv_open_count > 0 ||
2155 atomic_read(&zv->zv_suspend_ref)) {
2156 mutex_exit(&zv->zv_state_lock);
2163 * Cleared while holding zvol_state_lock as a writer
2164 * which will prevent zvol_open() from opening it.
2166 zv->zv_disk->private_data = NULL;
2168 /* Drop zv_state_lock before zvol_free() */
2169 mutex_exit(&zv->zv_state_lock);
2171 /* Try parallel zv_free, if failed do it in place */
2172 t = taskq_dispatch(system_taskq, zvol_free, zv,
2174 if (t == TASKQID_INVALID)
2175 list_insert_head(&free_list, zv);
2179 mutex_exit(&zv->zv_state_lock);
2182 rw_exit(&zvol_state_lock);
2184 /* Drop zvol_state_lock before calling zvol_free() */
2185 while ((zv = list_head(&free_list)) != NULL) {
2186 list_remove(&free_list, zv);
2190 if (tid != TASKQID_INVALID)
2191 taskq_wait_outstanding(system_taskq, tid);
2194 /* Remove minor for this specific volume only */
2196 zvol_remove_minor_impl(const char *name)
2198 zvol_state_t *zv = NULL, *zv_next;
2200 if (zvol_inhibit_dev)
2203 rw_enter(&zvol_state_lock, RW_WRITER);
2205 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
2206 zv_next = list_next(&zvol_state_list, zv);
2208 mutex_enter(&zv->zv_state_lock);
2209 if (strcmp(zv->zv_name, name) == 0) {
2211 * By holding zv_state_lock here, we guarantee that no
2212 * one is currently using this zv
2215 /* If in use, leave alone */
2216 if (zv->zv_open_count > 0 ||
2217 atomic_read(&zv->zv_suspend_ref)) {
2218 mutex_exit(&zv->zv_state_lock);
2224 * Cleared while holding zvol_state_lock as a writer
2225 * which will prevent zvol_open() from opening it.
2227 zv->zv_disk->private_data = NULL;
2229 mutex_exit(&zv->zv_state_lock);
2232 mutex_exit(&zv->zv_state_lock);
2236 /* Drop zvol_state_lock before calling zvol_free() */
2237 rw_exit(&zvol_state_lock);
2244 * Rename minors for specified dataset including children and snapshots.
2247 zvol_rename_minors_impl(const char *oldname, const char *newname)
2249 zvol_state_t *zv, *zv_next;
2250 int oldnamelen, newnamelen;
2252 if (zvol_inhibit_dev)
2255 oldnamelen = strlen(oldname);
2256 newnamelen = strlen(newname);
2258 rw_enter(&zvol_state_lock, RW_READER);
2260 for (zv = list_head(&zvol_state_list); zv != NULL; zv = zv_next) {
2261 zv_next = list_next(&zvol_state_list, zv);
2263 mutex_enter(&zv->zv_state_lock);
2265 if (strcmp(zv->zv_name, oldname) == 0) {
2266 zvol_rename_minor(zv, newname);
2267 } else if (strncmp(zv->zv_name, oldname, oldnamelen) == 0 &&
2268 (zv->zv_name[oldnamelen] == '/' ||
2269 zv->zv_name[oldnamelen] == '@')) {
2270 char *name = kmem_asprintf("%s%c%s", newname,
2271 zv->zv_name[oldnamelen],
2272 zv->zv_name + oldnamelen + 1);
2273 zvol_rename_minor(zv, name);
2277 mutex_exit(&zv->zv_state_lock);
2280 rw_exit(&zvol_state_lock);
2283 typedef struct zvol_snapdev_cb_arg {
2285 } zvol_snapdev_cb_arg_t;
2288 zvol_set_snapdev_cb(const char *dsname, void *param)
2290 zvol_snapdev_cb_arg_t *arg = param;
2292 if (strchr(dsname, '@') == NULL)
2295 switch (arg->snapdev) {
2296 case ZFS_SNAPDEV_VISIBLE:
2297 (void) zvol_create_minor_impl(dsname);
2299 case ZFS_SNAPDEV_HIDDEN:
2300 (void) zvol_remove_minor_impl(dsname);
2308 zvol_set_snapdev_impl(char *name, uint64_t snapdev)
2310 zvol_snapdev_cb_arg_t arg = {snapdev};
2311 fstrans_cookie_t cookie = spl_fstrans_mark();
2313 * The zvol_set_snapdev_sync() sets snapdev appropriately
2314 * in the dataset hierarchy. Here, we only scan snapshots.
2316 dmu_objset_find(name, zvol_set_snapdev_cb, &arg, DS_FIND_SNAPSHOTS);
2317 spl_fstrans_unmark(cookie);
2320 typedef struct zvol_volmode_cb_arg {
2322 } zvol_volmode_cb_arg_t;
2325 zvol_set_volmode_impl(char *name, uint64_t volmode)
2327 fstrans_cookie_t cookie = spl_fstrans_mark();
2329 if (strchr(name, '@') != NULL)
2333 * It's unfortunate we need to remove minors before we create new ones:
2334 * this is necessary because our backing gendisk (zvol_state->zv_disk)
2335 * coule be different when we set, for instance, volmode from "geom"
2336 * to "dev" (or vice versa).
2337 * A possible optimization is to modify our consumers so we don't get
2338 * called when "volmode" does not change.
2341 case ZFS_VOLMODE_NONE:
2342 (void) zvol_remove_minor_impl(name);
2344 case ZFS_VOLMODE_GEOM:
2345 case ZFS_VOLMODE_DEV:
2346 (void) zvol_remove_minor_impl(name);
2347 (void) zvol_create_minor_impl(name);
2349 case ZFS_VOLMODE_DEFAULT:
2350 (void) zvol_remove_minor_impl(name);
2351 if (zvol_volmode == ZFS_VOLMODE_NONE)
2353 else /* if zvol_volmode is invalid defaults to "geom" */
2354 (void) zvol_create_minor_impl(name);
2358 spl_fstrans_unmark(cookie);
2361 static zvol_task_t *
2362 zvol_task_alloc(zvol_async_op_t op, const char *name1, const char *name2,
2368 /* Never allow tasks on hidden names. */
2369 if (name1[0] == '$')
2372 task = kmem_zalloc(sizeof (zvol_task_t), KM_SLEEP);
2374 task->value = value;
2375 delim = strchr(name1, '/');
2376 strlcpy(task->pool, name1, delim ? (delim - name1 + 1) : MAXNAMELEN);
2378 strlcpy(task->name1, name1, MAXNAMELEN);
2380 strlcpy(task->name2, name2, MAXNAMELEN);
2386 zvol_task_free(zvol_task_t *task)
2388 kmem_free(task, sizeof (zvol_task_t));
2392 * The worker thread function performed asynchronously.
2395 zvol_task_cb(void *param)
2397 zvol_task_t *task = (zvol_task_t *)param;
2400 case ZVOL_ASYNC_CREATE_MINORS:
2401 (void) zvol_create_minors_impl(task->name1);
2403 case ZVOL_ASYNC_REMOVE_MINORS:
2404 zvol_remove_minors_impl(task->name1);
2406 case ZVOL_ASYNC_RENAME_MINORS:
2407 zvol_rename_minors_impl(task->name1, task->name2);
2409 case ZVOL_ASYNC_SET_SNAPDEV:
2410 zvol_set_snapdev_impl(task->name1, task->value);
2412 case ZVOL_ASYNC_SET_VOLMODE:
2413 zvol_set_volmode_impl(task->name1, task->value);
2420 zvol_task_free(task);
2423 typedef struct zvol_set_prop_int_arg {
2424 const char *zsda_name;
2425 uint64_t zsda_value;
2426 zprop_source_t zsda_source;
2428 } zvol_set_prop_int_arg_t;
2431 * Sanity check the dataset for safe use by the sync task. No additional
2432 * conditions are imposed.
2435 zvol_set_snapdev_check(void *arg, dmu_tx_t *tx)
2437 zvol_set_prop_int_arg_t *zsda = arg;
2438 dsl_pool_t *dp = dmu_tx_pool(tx);
2442 error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL);
2446 dsl_dir_rele(dd, FTAG);
2453 zvol_set_snapdev_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
2455 char dsname[MAXNAMELEN];
2459 dsl_dataset_name(ds, dsname);
2460 if (dsl_prop_get_int_ds(ds, "snapdev", &snapdev) != 0)
2462 task = zvol_task_alloc(ZVOL_ASYNC_SET_SNAPDEV, dsname, NULL, snapdev);
2466 (void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb,
2472 * Traverse all child datasets and apply snapdev appropriately.
2473 * We call dsl_prop_set_sync_impl() here to set the value only on the toplevel
2474 * dataset and read the effective "snapdev" on every child in the callback
2475 * function: this is because the value is not guaranteed to be the same in the
2476 * whole dataset hierarchy.
2479 zvol_set_snapdev_sync(void *arg, dmu_tx_t *tx)
2481 zvol_set_prop_int_arg_t *zsda = arg;
2482 dsl_pool_t *dp = dmu_tx_pool(tx);
2487 VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL));
2490 error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds);
2492 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_SNAPDEV),
2493 zsda->zsda_source, sizeof (zsda->zsda_value), 1,
2494 &zsda->zsda_value, zsda->zsda_tx);
2495 dsl_dataset_rele(ds, FTAG);
2497 dmu_objset_find_dp(dp, dd->dd_object, zvol_set_snapdev_sync_cb,
2498 zsda, DS_FIND_CHILDREN);
2500 dsl_dir_rele(dd, FTAG);
2504 zvol_set_snapdev(const char *ddname, zprop_source_t source, uint64_t snapdev)
2506 zvol_set_prop_int_arg_t zsda;
2508 zsda.zsda_name = ddname;
2509 zsda.zsda_source = source;
2510 zsda.zsda_value = snapdev;
2512 return (dsl_sync_task(ddname, zvol_set_snapdev_check,
2513 zvol_set_snapdev_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE));
2517 * Sanity check the dataset for safe use by the sync task. No additional
2518 * conditions are imposed.
2521 zvol_set_volmode_check(void *arg, dmu_tx_t *tx)
2523 zvol_set_prop_int_arg_t *zsda = arg;
2524 dsl_pool_t *dp = dmu_tx_pool(tx);
2528 error = dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL);
2532 dsl_dir_rele(dd, FTAG);
2539 zvol_set_volmode_sync_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
2541 char dsname[MAXNAMELEN];
2545 dsl_dataset_name(ds, dsname);
2546 if (dsl_prop_get_int_ds(ds, "volmode", &volmode) != 0)
2548 task = zvol_task_alloc(ZVOL_ASYNC_SET_VOLMODE, dsname, NULL, volmode);
2552 (void) taskq_dispatch(dp->dp_spa->spa_zvol_taskq, zvol_task_cb,
2558 * Traverse all child datasets and apply volmode appropriately.
2559 * We call dsl_prop_set_sync_impl() here to set the value only on the toplevel
2560 * dataset and read the effective "volmode" on every child in the callback
2561 * function: this is because the value is not guaranteed to be the same in the
2562 * whole dataset hierarchy.
2565 zvol_set_volmode_sync(void *arg, dmu_tx_t *tx)
2567 zvol_set_prop_int_arg_t *zsda = arg;
2568 dsl_pool_t *dp = dmu_tx_pool(tx);
2573 VERIFY0(dsl_dir_hold(dp, zsda->zsda_name, FTAG, &dd, NULL));
2576 error = dsl_dataset_hold(dp, zsda->zsda_name, FTAG, &ds);
2578 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_VOLMODE),
2579 zsda->zsda_source, sizeof (zsda->zsda_value), 1,
2580 &zsda->zsda_value, zsda->zsda_tx);
2581 dsl_dataset_rele(ds, FTAG);
2584 dmu_objset_find_dp(dp, dd->dd_object, zvol_set_volmode_sync_cb,
2585 zsda, DS_FIND_CHILDREN);
2587 dsl_dir_rele(dd, FTAG);
2591 zvol_set_volmode(const char *ddname, zprop_source_t source, uint64_t volmode)
2593 zvol_set_prop_int_arg_t zsda;
2595 zsda.zsda_name = ddname;
2596 zsda.zsda_source = source;
2597 zsda.zsda_value = volmode;
2599 return (dsl_sync_task(ddname, zvol_set_volmode_check,
2600 zvol_set_volmode_sync, &zsda, 0, ZFS_SPACE_CHECK_NONE));
2604 zvol_create_minors(spa_t *spa, const char *name, boolean_t async)
2609 task = zvol_task_alloc(ZVOL_ASYNC_CREATE_MINORS, name, NULL, ~0ULL);
2613 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
2614 if ((async == B_FALSE) && (id != TASKQID_INVALID))
2615 taskq_wait_id(spa->spa_zvol_taskq, id);
2619 zvol_remove_minors(spa_t *spa, const char *name, boolean_t async)
2624 task = zvol_task_alloc(ZVOL_ASYNC_REMOVE_MINORS, name, NULL, ~0ULL);
2628 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
2629 if ((async == B_FALSE) && (id != TASKQID_INVALID))
2630 taskq_wait_id(spa->spa_zvol_taskq, id);
2634 zvol_rename_minors(spa_t *spa, const char *name1, const char *name2,
2640 task = zvol_task_alloc(ZVOL_ASYNC_RENAME_MINORS, name1, name2, ~0ULL);
2644 id = taskq_dispatch(spa->spa_zvol_taskq, zvol_task_cb, task, TQ_SLEEP);
2645 if ((async == B_FALSE) && (id != TASKQID_INVALID))
2646 taskq_wait_id(spa->spa_zvol_taskq, id);
2652 int threads = MIN(MAX(zvol_threads, 1), 1024);
2655 list_create(&zvol_state_list, sizeof (zvol_state_t),
2656 offsetof(zvol_state_t, zv_next));
2657 rw_init(&zvol_state_lock, NULL, RW_DEFAULT, NULL);
2658 ida_init(&zvol_ida);
2660 zvol_taskq = taskq_create(ZVOL_DRIVER, threads, maxclsyspri,
2661 threads * 2, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC);
2662 if (zvol_taskq == NULL) {
2663 printk(KERN_INFO "ZFS: taskq_create() failed\n");
2668 zvol_htable = kmem_alloc(ZVOL_HT_SIZE * sizeof (struct hlist_head),
2674 for (i = 0; i < ZVOL_HT_SIZE; i++)
2675 INIT_HLIST_HEAD(&zvol_htable[i]);
2677 error = register_blkdev(zvol_major, ZVOL_DRIVER);
2679 printk(KERN_INFO "ZFS: register_blkdev() failed %d\n", error);
2683 blk_register_region(MKDEV(zvol_major, 0), 1UL << MINORBITS,
2684 THIS_MODULE, zvol_probe, NULL, NULL);
2689 kmem_free(zvol_htable, ZVOL_HT_SIZE * sizeof (struct hlist_head));
2691 taskq_destroy(zvol_taskq);
2693 ida_destroy(&zvol_ida);
2694 rw_destroy(&zvol_state_lock);
2695 list_destroy(&zvol_state_list);
2697 return (SET_ERROR(error));
2703 zvol_remove_minors_impl(NULL);
2705 blk_unregister_region(MKDEV(zvol_major, 0), 1UL << MINORBITS);
2706 unregister_blkdev(zvol_major, ZVOL_DRIVER);
2707 kmem_free(zvol_htable, ZVOL_HT_SIZE * sizeof (struct hlist_head));
2709 taskq_destroy(zvol_taskq);
2710 list_destroy(&zvol_state_list);
2711 rw_destroy(&zvol_state_lock);
2713 ida_destroy(&zvol_ida);
2717 module_param(zvol_inhibit_dev, uint, 0644);
2718 MODULE_PARM_DESC(zvol_inhibit_dev, "Do not create zvol device nodes");
2720 module_param(zvol_major, uint, 0444);
2721 MODULE_PARM_DESC(zvol_major, "Major number for zvol device");
2723 module_param(zvol_threads, uint, 0444);
2724 MODULE_PARM_DESC(zvol_threads, "Max number of threads to handle I/O requests");
2726 module_param(zvol_request_sync, uint, 0644);
2727 MODULE_PARM_DESC(zvol_request_sync, "Synchronously handle bio requests");
2729 module_param(zvol_max_discard_blocks, ulong, 0444);
2730 MODULE_PARM_DESC(zvol_max_discard_blocks, "Max number of blocks to discard");
2732 module_param(zvol_prefetch_bytes, uint, 0644);
2733 MODULE_PARM_DESC(zvol_prefetch_bytes, "Prefetch N bytes at zvol start+end");
2735 module_param(zvol_volmode, uint, 0644);
2736 MODULE_PARM_DESC(zvol_volmode, "Default volmode property value");