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, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
26 #include <sys/dsl_scan.h>
27 #include <sys/dsl_pool.h>
28 #include <sys/dsl_dataset.h>
29 #include <sys/dsl_prop.h>
30 #include <sys/dsl_dir.h>
31 #include <sys/dsl_synctask.h>
32 #include <sys/dnode.h>
33 #include <sys/dmu_tx.h>
34 #include <sys/dmu_objset.h>
38 #include <sys/zfs_context.h>
39 #include <sys/fs/zfs.h>
40 #include <sys/zfs_znode.h>
41 #include <sys/spa_impl.h>
42 #include <sys/vdev_impl.h>
43 #include <sys/zil_impl.h>
44 #include <sys/zio_checksum.h>
47 #include <sys/sa_impl.h>
48 #include <sys/zfeature.h>
50 #include <sys/zfs_vfsops.h>
53 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *,
54 const zbookmark_phys_t *);
56 static scan_cb_t dsl_scan_scrub_cb;
57 static void dsl_scan_cancel_sync(void *, dmu_tx_t *);
58 static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *tx);
60 unsigned int zfs_top_maxinflight = 32; /* maximum I/Os per top-level */
61 unsigned int zfs_resilver_delay = 2; /* number of ticks to delay resilver */
62 unsigned int zfs_scrub_delay = 4; /* number of ticks to delay scrub */
63 unsigned int zfs_scan_idle = 50; /* idle window in clock ticks */
65 unsigned int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
66 unsigned int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
67 unsigned int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver
69 boolean_t zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
70 boolean_t zfs_no_scrub_prefetch = B_FALSE; /* set to disable scrub prefetch */
72 SYSCTL_DECL(_vfs_zfs);
73 TUNABLE_INT("vfs.zfs.top_maxinflight", &zfs_top_maxinflight);
74 SYSCTL_UINT(_vfs_zfs, OID_AUTO, top_maxinflight, CTLFLAG_RW,
75 &zfs_top_maxinflight, 0, "Maximum I/Os per top-level vdev");
76 TUNABLE_INT("vfs.zfs.resilver_delay", &zfs_resilver_delay);
77 SYSCTL_UINT(_vfs_zfs, OID_AUTO, resilver_delay, CTLFLAG_RW,
78 &zfs_resilver_delay, 0, "Number of ticks to delay resilver");
79 TUNABLE_INT("vfs.zfs.scrub_delay", &zfs_scrub_delay);
80 SYSCTL_UINT(_vfs_zfs, OID_AUTO, scrub_delay, CTLFLAG_RW,
81 &zfs_scrub_delay, 0, "Number of ticks to delay scrub");
82 TUNABLE_INT("vfs.zfs.scan_idle", &zfs_scan_idle);
83 SYSCTL_UINT(_vfs_zfs, OID_AUTO, scan_idle, CTLFLAG_RW,
84 &zfs_scan_idle, 0, "Idle scan window in clock ticks");
85 TUNABLE_INT("vfs.zfs.scan_min_time_ms", &zfs_scan_min_time_ms);
86 SYSCTL_UINT(_vfs_zfs, OID_AUTO, scan_min_time_ms, CTLFLAG_RW,
87 &zfs_scan_min_time_ms, 0, "Min millisecs to scrub per txg");
88 TUNABLE_INT("vfs.zfs.free_min_time_ms", &zfs_free_min_time_ms);
89 SYSCTL_UINT(_vfs_zfs, OID_AUTO, free_min_time_ms, CTLFLAG_RW,
90 &zfs_free_min_time_ms, 0, "Min millisecs to free per txg");
91 TUNABLE_INT("vfs.zfs.resilver_min_time_ms", &zfs_resilver_min_time_ms);
92 SYSCTL_UINT(_vfs_zfs, OID_AUTO, resilver_min_time_ms, CTLFLAG_RW,
93 &zfs_resilver_min_time_ms, 0, "Min millisecs to resilver per txg");
94 TUNABLE_INT("vfs.zfs.no_scrub_io", &zfs_no_scrub_io);
95 SYSCTL_INT(_vfs_zfs, OID_AUTO, no_scrub_io, CTLFLAG_RW,
96 &zfs_no_scrub_io, 0, "Disable scrub I/O");
97 TUNABLE_INT("vfs.zfs.no_scrub_prefetch", &zfs_no_scrub_prefetch);
98 SYSCTL_INT(_vfs_zfs, OID_AUTO, no_scrub_prefetch, CTLFLAG_RW,
99 &zfs_no_scrub_prefetch, 0, "Disable scrub prefetching");
101 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
102 /* max number of blocks to free in a single TXG */
103 uint64_t zfs_free_max_blocks = UINT64_MAX;
104 SYSCTL_UQUAD(_vfs_zfs, OID_AUTO, free_max_blocks, CTLFLAG_RWTUN,
105 &zfs_free_max_blocks, 0, "Maximum number of blocks to free in one TXG");
108 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
109 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
110 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
112 extern int zfs_txg_timeout;
114 /* the order has to match pool_scan_type */
115 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
117 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
118 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
122 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
126 spa_t *spa = dp->dp_spa;
129 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
133 * It's possible that we're resuming a scan after a reboot so
134 * make sure that the scan_async_destroying flag is initialized
137 ASSERT(!scn->scn_async_destroying);
138 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
139 SPA_FEATURE_ASYNC_DESTROY);
141 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
142 "scrub_func", sizeof (uint64_t), 1, &f);
145 * There was an old-style scrub in progress. Restart a
146 * new-style scrub from the beginning.
148 scn->scn_restart_txg = txg;
149 zfs_dbgmsg("old-style scrub was in progress; "
150 "restarting new-style scrub in txg %llu",
151 scn->scn_restart_txg);
154 * Load the queue obj from the old location so that it
155 * can be freed by dsl_scan_done().
157 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
158 "scrub_queue", sizeof (uint64_t), 1,
159 &scn->scn_phys.scn_queue_obj);
161 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
162 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
169 if (scn->scn_phys.scn_state == DSS_SCANNING &&
170 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
172 * A new-type scrub was in progress on an old
173 * pool, and the pool was accessed by old
174 * software. Restart from the beginning, since
175 * the old software may have changed the pool in
178 scn->scn_restart_txg = txg;
179 zfs_dbgmsg("new-style scrub was modified "
180 "by old software; restarting in txg %llu",
181 scn->scn_restart_txg);
185 spa_scan_stat_init(spa);
190 dsl_scan_fini(dsl_pool_t *dp)
193 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
200 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
202 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
204 if (scn->scn_phys.scn_state == DSS_SCANNING)
205 return (SET_ERROR(EBUSY));
211 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
213 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
214 pool_scan_func_t *funcp = arg;
215 dmu_object_type_t ot = 0;
216 dsl_pool_t *dp = scn->scn_dp;
217 spa_t *spa = dp->dp_spa;
219 ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
220 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
221 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
222 scn->scn_phys.scn_func = *funcp;
223 scn->scn_phys.scn_state = DSS_SCANNING;
224 scn->scn_phys.scn_min_txg = 0;
225 scn->scn_phys.scn_max_txg = tx->tx_txg;
226 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
227 scn->scn_phys.scn_start_time = gethrestime_sec();
228 scn->scn_phys.scn_errors = 0;
229 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
230 scn->scn_restart_txg = 0;
231 scn->scn_done_txg = 0;
232 spa_scan_stat_init(spa);
234 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
235 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
237 /* rewrite all disk labels */
238 vdev_config_dirty(spa->spa_root_vdev);
240 if (vdev_resilver_needed(spa->spa_root_vdev,
241 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
242 spa_event_notify(spa, NULL, ESC_ZFS_RESILVER_START);
244 spa_event_notify(spa, NULL, ESC_ZFS_SCRUB_START);
247 spa->spa_scrub_started = B_TRUE;
249 * If this is an incremental scrub, limit the DDT scrub phase
250 * to just the auto-ditto class (for correctness); the rest
251 * of the scrub should go faster using top-down pruning.
253 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
254 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
258 /* back to the generic stuff */
260 if (dp->dp_blkstats == NULL) {
262 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
264 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
266 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
267 ot = DMU_OT_ZAP_OTHER;
269 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
270 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
272 dsl_scan_sync_state(scn, tx);
274 spa_history_log_internal(spa, "scan setup", tx,
275 "func=%u mintxg=%llu maxtxg=%llu",
276 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
281 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
283 static const char *old_names[] = {
285 "scrub_ddt_bookmark",
286 "scrub_ddt_class_max",
295 dsl_pool_t *dp = scn->scn_dp;
296 spa_t *spa = dp->dp_spa;
299 /* Remove any remnants of an old-style scrub. */
300 for (i = 0; old_names[i]; i++) {
301 (void) zap_remove(dp->dp_meta_objset,
302 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
305 if (scn->scn_phys.scn_queue_obj != 0) {
306 VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
307 scn->scn_phys.scn_queue_obj, tx));
308 scn->scn_phys.scn_queue_obj = 0;
312 * If we were "restarted" from a stopped state, don't bother
313 * with anything else.
315 if (scn->scn_phys.scn_state != DSS_SCANNING)
319 scn->scn_phys.scn_state = DSS_FINISHED;
321 scn->scn_phys.scn_state = DSS_CANCELED;
323 spa_history_log_internal(spa, "scan done", tx,
324 "complete=%u", complete);
326 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
327 mutex_enter(&spa->spa_scrub_lock);
328 while (spa->spa_scrub_inflight > 0) {
329 cv_wait(&spa->spa_scrub_io_cv,
330 &spa->spa_scrub_lock);
332 mutex_exit(&spa->spa_scrub_lock);
333 spa->spa_scrub_started = B_FALSE;
334 spa->spa_scrub_active = B_FALSE;
337 * If the scrub/resilver completed, update all DTLs to
338 * reflect this. Whether it succeeded or not, vacate
339 * all temporary scrub DTLs.
341 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
342 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
344 spa_event_notify(spa, NULL, scn->scn_phys.scn_min_txg ?
345 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
347 spa_errlog_rotate(spa);
350 * We may have finished replacing a device.
351 * Let the async thread assess this and handle the detach.
353 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
356 scn->scn_phys.scn_end_time = gethrestime_sec();
361 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
363 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
365 if (scn->scn_phys.scn_state != DSS_SCANNING)
366 return (SET_ERROR(ENOENT));
372 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
374 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
376 dsl_scan_done(scn, B_FALSE, tx);
377 dsl_scan_sync_state(scn, tx);
381 dsl_scan_cancel(dsl_pool_t *dp)
383 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
384 dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED));
387 static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
388 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
389 dmu_objset_type_t ostype, dmu_tx_t *tx);
390 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
391 dmu_objset_type_t ostype,
392 dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
395 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
397 zio_free(dp->dp_spa, txg, bp);
401 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
403 ASSERT(dsl_pool_sync_context(dp));
404 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, BP_GET_PSIZE(bpp),
409 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
411 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
412 if (ds->ds_is_snapshot)
413 return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
418 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
420 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
421 DMU_POOL_DIRECTORY_OBJECT,
422 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
423 &scn->scn_phys, tx));
426 extern int zfs_vdev_async_write_active_min_dirty_percent;
429 dsl_scan_check_pause(dsl_scan_t *scn, const zbookmark_phys_t *zb)
431 /* we never skip user/group accounting objects */
432 if (zb && (int64_t)zb->zb_object < 0)
435 if (scn->scn_pausing)
436 return (B_TRUE); /* we're already pausing */
438 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
439 return (B_FALSE); /* we're resuming */
441 /* We only know how to resume from level-0 blocks. */
442 if (zb && zb->zb_level != 0)
447 * - we have scanned for the maximum time: an entire txg
448 * timeout (default 5 sec)
450 * - we have scanned for at least the minimum time (default 1 sec
451 * for scrub, 3 sec for resilver), and either we have sufficient
452 * dirty data that we are starting to write more quickly
453 * (default 30%), or someone is explicitly waiting for this txg
456 * - the spa is shutting down because this pool is being exported
457 * or the machine is rebooting.
459 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
460 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
461 uint64_t elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
462 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
463 if (elapsed_nanosecs / NANOSEC >= zfs_txg_timeout ||
464 (NSEC2MSEC(elapsed_nanosecs) > mintime &&
465 (txg_sync_waiting(scn->scn_dp) ||
466 dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent)) ||
467 spa_shutting_down(scn->scn_dp->dp_spa)) {
469 dprintf("pausing at bookmark %llx/%llx/%llx/%llx\n",
470 (longlong_t)zb->zb_objset,
471 (longlong_t)zb->zb_object,
472 (longlong_t)zb->zb_level,
473 (longlong_t)zb->zb_blkid);
474 scn->scn_phys.scn_bookmark = *zb;
476 dprintf("pausing at DDT bookmark %llx/%llx/%llx/%llx\n",
477 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
478 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
479 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
480 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
481 scn->scn_pausing = B_TRUE;
487 typedef struct zil_scan_arg {
489 zil_header_t *zsa_zh;
494 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
496 zil_scan_arg_t *zsa = arg;
497 dsl_pool_t *dp = zsa->zsa_dp;
498 dsl_scan_t *scn = dp->dp_scan;
499 zil_header_t *zh = zsa->zsa_zh;
502 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
506 * One block ("stubby") can be allocated a long time ago; we
507 * want to visit that one because it has been allocated
508 * (on-disk) even if it hasn't been claimed (even though for
509 * scrub there's nothing to do to it).
511 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(dp->dp_spa))
514 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
515 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
517 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
523 dsl_scan_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
525 if (lrc->lrc_txtype == TX_WRITE) {
526 zil_scan_arg_t *zsa = arg;
527 dsl_pool_t *dp = zsa->zsa_dp;
528 dsl_scan_t *scn = dp->dp_scan;
529 zil_header_t *zh = zsa->zsa_zh;
530 lr_write_t *lr = (lr_write_t *)lrc;
531 blkptr_t *bp = &lr->lr_blkptr;
534 if (BP_IS_HOLE(bp) ||
535 bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
539 * birth can be < claim_txg if this record's txg is
540 * already txg sync'ed (but this log block contains
541 * other records that are not synced)
543 if (claim_txg == 0 || bp->blk_birth < claim_txg)
546 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
547 lr->lr_foid, ZB_ZIL_LEVEL,
548 lr->lr_offset / BP_GET_LSIZE(bp));
550 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
556 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
558 uint64_t claim_txg = zh->zh_claim_txg;
559 zil_scan_arg_t zsa = { dp, zh };
563 * We only want to visit blocks that have been claimed but not yet
564 * replayed (or, in read-only mode, blocks that *would* be claimed).
566 if (claim_txg == 0 && spa_writeable(dp->dp_spa))
569 zilog = zil_alloc(dp->dp_meta_objset, zh);
571 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
579 dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
580 uint64_t objset, uint64_t object, uint64_t blkid)
582 zbookmark_phys_t czb;
583 arc_flags_t flags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
585 if (zfs_no_scrub_prefetch)
588 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_min_txg ||
589 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE))
592 SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
594 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
595 NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
596 ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
600 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
601 const zbookmark_phys_t *zb)
604 * We never skip over user/group accounting objects (obj<0)
606 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
607 (int64_t)zb->zb_object >= 0) {
609 * If we already visited this bp & everything below (in
610 * a prior txg sync), don't bother doing it again.
612 if (zbookmark_subtree_completed(dnp, zb,
613 &scn->scn_phys.scn_bookmark))
617 * If we found the block we're trying to resume from, or
618 * we went past it to a different object, zero it out to
619 * indicate that it's OK to start checking for pausing
622 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
623 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
624 dprintf("resuming at %llx/%llx/%llx/%llx\n",
625 (longlong_t)zb->zb_objset,
626 (longlong_t)zb->zb_object,
627 (longlong_t)zb->zb_level,
628 (longlong_t)zb->zb_blkid);
629 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
636 * Return nonzero on i/o error.
637 * Return new buf to write out in *bufp.
640 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
641 dnode_phys_t *dnp, const blkptr_t *bp,
642 const zbookmark_phys_t *zb, dmu_tx_t *tx)
644 dsl_pool_t *dp = scn->scn_dp;
645 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
648 if (BP_GET_LEVEL(bp) > 0) {
649 arc_flags_t flags = ARC_FLAG_WAIT;
652 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
655 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
656 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
658 scn->scn_phys.scn_errors++;
661 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
662 dsl_scan_prefetch(scn, buf, cbp, zb->zb_objset,
663 zb->zb_object, zb->zb_blkid * epb + i);
665 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
666 zbookmark_phys_t czb;
668 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
670 zb->zb_blkid * epb + i);
671 dsl_scan_visitbp(cbp, &czb, dnp,
672 ds, scn, ostype, tx);
674 (void) arc_buf_remove_ref(buf, &buf);
675 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
676 arc_flags_t flags = ARC_FLAG_WAIT;
679 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
682 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
683 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
685 scn->scn_phys.scn_errors++;
688 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
689 for (j = 0; j < cdnp->dn_nblkptr; j++) {
690 blkptr_t *cbp = &cdnp->dn_blkptr[j];
691 dsl_scan_prefetch(scn, buf, cbp,
692 zb->zb_objset, zb->zb_blkid * epb + i, j);
695 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
696 dsl_scan_visitdnode(scn, ds, ostype,
697 cdnp, zb->zb_blkid * epb + i, tx);
700 (void) arc_buf_remove_ref(buf, &buf);
701 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
702 arc_flags_t flags = ARC_FLAG_WAIT;
706 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
707 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
709 scn->scn_phys.scn_errors++;
715 dsl_scan_visitdnode(scn, ds, osp->os_type,
716 &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx);
718 if (OBJSET_BUF_HAS_USERUSED(buf)) {
720 * We also always visit user/group accounting
721 * objects, and never skip them, even if we are
722 * pausing. This is necessary so that the space
723 * deltas from this txg get integrated.
725 dsl_scan_visitdnode(scn, ds, osp->os_type,
726 &osp->os_groupused_dnode,
727 DMU_GROUPUSED_OBJECT, tx);
728 dsl_scan_visitdnode(scn, ds, osp->os_type,
729 &osp->os_userused_dnode,
730 DMU_USERUSED_OBJECT, tx);
732 (void) arc_buf_remove_ref(buf, &buf);
739 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
740 dmu_objset_type_t ostype, dnode_phys_t *dnp,
741 uint64_t object, dmu_tx_t *tx)
745 for (j = 0; j < dnp->dn_nblkptr; j++) {
746 zbookmark_phys_t czb;
748 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
749 dnp->dn_nlevels - 1, j);
750 dsl_scan_visitbp(&dnp->dn_blkptr[j],
751 &czb, dnp, ds, scn, ostype, tx);
754 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
755 zbookmark_phys_t czb;
756 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
758 dsl_scan_visitbp(&dnp->dn_spill,
759 &czb, dnp, ds, scn, ostype, tx);
764 * The arguments are in this order because mdb can only print the
765 * first 5; we want them to be useful.
768 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
769 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
770 dmu_objset_type_t ostype, dmu_tx_t *tx)
772 dsl_pool_t *dp = scn->scn_dp;
773 arc_buf_t *buf = NULL;
774 blkptr_t bp_toread = *bp;
776 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
778 if (dsl_scan_check_pause(scn, zb))
781 if (dsl_scan_check_resume(scn, dnp, zb))
787 scn->scn_visited_this_txg++;
790 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
791 ds, ds ? ds->ds_object : 0,
792 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
795 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
798 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx) != 0)
802 * If dsl_scan_ddt() has aready visited this block, it will have
803 * already done any translations or scrubbing, so don't call the
806 if (ddt_class_contains(dp->dp_spa,
807 scn->scn_phys.scn_ddt_class_max, bp)) {
813 * If this block is from the future (after cur_max_txg), then we
814 * are doing this on behalf of a deleted snapshot, and we will
815 * revisit the future block on the next pass of this dataset.
816 * Don't scan it now unless we need to because something
817 * under it was modified.
819 if (BP_PHYSICAL_BIRTH(bp) <= scn->scn_phys.scn_cur_max_txg) {
820 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
825 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
830 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
831 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
832 dsl_scan_visitbp(bp, &zb, NULL,
833 ds, scn, DMU_OST_NONE, tx);
835 dprintf_ds(ds, "finished scan%s", "");
839 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
841 dsl_pool_t *dp = ds->ds_dir->dd_pool;
842 dsl_scan_t *scn = dp->dp_scan;
845 if (scn->scn_phys.scn_state != DSS_SCANNING)
848 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
849 if (ds->ds_is_snapshot) {
850 /* Note, scn_cur_{min,max}_txg stays the same. */
851 scn->scn_phys.scn_bookmark.zb_objset =
852 dsl_dataset_phys(ds)->ds_next_snap_obj;
853 zfs_dbgmsg("destroying ds %llu; currently traversing; "
854 "reset zb_objset to %llu",
855 (u_longlong_t)ds->ds_object,
856 (u_longlong_t)dsl_dataset_phys(ds)->
858 scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
860 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
861 ZB_DESTROYED_OBJSET, 0, 0, 0);
862 zfs_dbgmsg("destroying ds %llu; currently traversing; "
863 "reset bookmark to -1,0,0,0",
864 (u_longlong_t)ds->ds_object);
866 } else if (zap_lookup_int_key(dp->dp_meta_objset,
867 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
868 ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
869 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
870 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
871 if (ds->ds_is_snapshot) {
873 * We keep the same mintxg; it could be >
874 * ds_creation_txg if the previous snapshot was
877 VERIFY(zap_add_int_key(dp->dp_meta_objset,
878 scn->scn_phys.scn_queue_obj,
879 dsl_dataset_phys(ds)->ds_next_snap_obj,
881 zfs_dbgmsg("destroying ds %llu; in queue; "
882 "replacing with %llu",
883 (u_longlong_t)ds->ds_object,
884 (u_longlong_t)dsl_dataset_phys(ds)->
887 zfs_dbgmsg("destroying ds %llu; in queue; removing",
888 (u_longlong_t)ds->ds_object);
891 zfs_dbgmsg("destroying ds %llu; ignoring",
892 (u_longlong_t)ds->ds_object);
896 * dsl_scan_sync() should be called after this, and should sync
897 * out our changed state, but just to be safe, do it here.
899 dsl_scan_sync_state(scn, tx);
903 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
905 dsl_pool_t *dp = ds->ds_dir->dd_pool;
906 dsl_scan_t *scn = dp->dp_scan;
909 if (scn->scn_phys.scn_state != DSS_SCANNING)
912 ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
914 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
915 scn->scn_phys.scn_bookmark.zb_objset =
916 dsl_dataset_phys(ds)->ds_prev_snap_obj;
917 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
918 "reset zb_objset to %llu",
919 (u_longlong_t)ds->ds_object,
920 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
921 } else if (zap_lookup_int_key(dp->dp_meta_objset,
922 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
923 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
924 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
925 VERIFY(zap_add_int_key(dp->dp_meta_objset,
926 scn->scn_phys.scn_queue_obj,
927 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg, tx) == 0);
928 zfs_dbgmsg("snapshotting ds %llu; in queue; "
929 "replacing with %llu",
930 (u_longlong_t)ds->ds_object,
931 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
933 dsl_scan_sync_state(scn, tx);
937 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
939 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
940 dsl_scan_t *scn = dp->dp_scan;
943 if (scn->scn_phys.scn_state != DSS_SCANNING)
946 if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
947 scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
948 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
949 "reset zb_objset to %llu",
950 (u_longlong_t)ds1->ds_object,
951 (u_longlong_t)ds2->ds_object);
952 } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
953 scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
954 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
955 "reset zb_objset to %llu",
956 (u_longlong_t)ds2->ds_object,
957 (u_longlong_t)ds1->ds_object);
960 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
961 ds1->ds_object, &mintxg) == 0) {
964 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
965 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
966 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
967 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
968 err = zap_add_int_key(dp->dp_meta_objset,
969 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
970 VERIFY(err == 0 || err == EEXIST);
972 /* Both were there to begin with */
973 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
974 scn->scn_phys.scn_queue_obj,
975 ds1->ds_object, mintxg, tx));
977 zfs_dbgmsg("clone_swap ds %llu; in queue; "
978 "replacing with %llu",
979 (u_longlong_t)ds1->ds_object,
980 (u_longlong_t)ds2->ds_object);
981 } else if (zap_lookup_int_key(dp->dp_meta_objset,
982 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
983 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
984 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
985 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
986 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
987 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
988 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
989 zfs_dbgmsg("clone_swap ds %llu; in queue; "
990 "replacing with %llu",
991 (u_longlong_t)ds2->ds_object,
992 (u_longlong_t)ds1->ds_object);
995 dsl_scan_sync_state(scn, tx);
998 struct enqueue_clones_arg {
1005 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1007 struct enqueue_clones_arg *eca = arg;
1010 dsl_scan_t *scn = dp->dp_scan;
1012 if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != eca->originobj)
1015 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1019 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != eca->originobj) {
1020 dsl_dataset_t *prev;
1021 err = dsl_dataset_hold_obj(dp,
1022 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1024 dsl_dataset_rele(ds, FTAG);
1029 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1030 scn->scn_phys.scn_queue_obj, ds->ds_object,
1031 dsl_dataset_phys(ds)->ds_prev_snap_txg, eca->tx) == 0);
1032 dsl_dataset_rele(ds, FTAG);
1037 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
1039 dsl_pool_t *dp = scn->scn_dp;
1043 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1045 if (dmu_objset_from_ds(ds, &os))
1049 * Only the ZIL in the head (non-snapshot) is valid. Even though
1050 * snapshots can have ZIL block pointers (which may be the same
1051 * BP as in the head), they must be ignored. So we traverse the
1052 * ZIL here, rather than in scan_recurse(), because the regular
1053 * snapshot block-sharing rules don't apply to it.
1055 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !ds->ds_is_snapshot)
1056 dsl_scan_zil(dp, &os->os_zil_header);
1059 * Iterate over the bps in this ds.
1061 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1062 dsl_scan_visit_rootbp(scn, ds, &dsl_dataset_phys(ds)->ds_bp, tx);
1064 char *dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
1065 dsl_dataset_name(ds, dsname);
1066 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1068 (longlong_t)dsobj, dsname,
1069 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1070 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1071 (int)scn->scn_pausing);
1072 kmem_free(dsname, ZFS_MAXNAMELEN);
1074 if (scn->scn_pausing)
1078 * We've finished this pass over this dataset.
1082 * If we did not completely visit this dataset, do another pass.
1084 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1085 zfs_dbgmsg("incomplete pass; visiting again");
1086 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1087 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1088 scn->scn_phys.scn_queue_obj, ds->ds_object,
1089 scn->scn_phys.scn_cur_max_txg, tx) == 0);
1094 * Add descendent datasets to work queue.
1096 if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
1097 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1098 scn->scn_phys.scn_queue_obj,
1099 dsl_dataset_phys(ds)->ds_next_snap_obj,
1100 dsl_dataset_phys(ds)->ds_creation_txg, tx) == 0);
1102 if (dsl_dataset_phys(ds)->ds_num_children > 1) {
1103 boolean_t usenext = B_FALSE;
1104 if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
1107 * A bug in a previous version of the code could
1108 * cause upgrade_clones_cb() to not set
1109 * ds_next_snap_obj when it should, leading to a
1110 * missing entry. Therefore we can only use the
1111 * next_clones_obj when its count is correct.
1113 int err = zap_count(dp->dp_meta_objset,
1114 dsl_dataset_phys(ds)->ds_next_clones_obj, &count);
1116 count == dsl_dataset_phys(ds)->ds_num_children - 1)
1121 VERIFY0(zap_join_key(dp->dp_meta_objset,
1122 dsl_dataset_phys(ds)->ds_next_clones_obj,
1123 scn->scn_phys.scn_queue_obj,
1124 dsl_dataset_phys(ds)->ds_creation_txg, tx));
1126 struct enqueue_clones_arg eca;
1128 eca.originobj = ds->ds_object;
1130 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1131 enqueue_clones_cb, &eca, DS_FIND_CHILDREN));
1136 dsl_dataset_rele(ds, FTAG);
1141 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1146 dsl_scan_t *scn = dp->dp_scan;
1148 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1152 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1153 dsl_dataset_t *prev;
1154 err = dsl_dataset_hold_obj(dp,
1155 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1157 dsl_dataset_rele(ds, FTAG);
1162 * If this is a clone, we don't need to worry about it for now.
1164 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) {
1165 dsl_dataset_rele(ds, FTAG);
1166 dsl_dataset_rele(prev, FTAG);
1169 dsl_dataset_rele(ds, FTAG);
1173 VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1174 ds->ds_object, dsl_dataset_phys(ds)->ds_prev_snap_txg, tx) == 0);
1175 dsl_dataset_rele(ds, FTAG);
1180 * Scrub/dedup interaction.
1182 * If there are N references to a deduped block, we don't want to scrub it
1183 * N times -- ideally, we should scrub it exactly once.
1185 * We leverage the fact that the dde's replication class (enum ddt_class)
1186 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1187 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1189 * To prevent excess scrubbing, the scrub begins by walking the DDT
1190 * to find all blocks with refcnt > 1, and scrubs each of these once.
1191 * Since there are two replication classes which contain blocks with
1192 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1193 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1195 * There would be nothing more to say if a block's refcnt couldn't change
1196 * during a scrub, but of course it can so we must account for changes
1197 * in a block's replication class.
1199 * Here's an example of what can occur:
1201 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
1202 * when visited during the top-down scrub phase, it will be scrubbed twice.
1203 * This negates our scrub optimization, but is otherwise harmless.
1205 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1206 * on each visit during the top-down scrub phase, it will never be scrubbed.
1207 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1208 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1209 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1210 * while a scrub is in progress, it scrubs the block right then.
1213 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1215 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1216 ddt_entry_t dde = { 0 };
1220 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1223 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1225 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1226 (longlong_t)ddb->ddb_class,
1227 (longlong_t)ddb->ddb_type,
1228 (longlong_t)ddb->ddb_checksum,
1229 (longlong_t)ddb->ddb_cursor);
1231 /* There should be no pending changes to the dedup table */
1232 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1233 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
1235 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1238 if (dsl_scan_check_pause(scn, NULL))
1242 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; pausing=%u",
1243 (longlong_t)n, (int)scn->scn_phys.scn_ddt_class_max,
1244 (int)scn->scn_pausing);
1246 ASSERT(error == 0 || error == ENOENT);
1247 ASSERT(error != ENOENT ||
1248 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1253 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1254 ddt_entry_t *dde, dmu_tx_t *tx)
1256 const ddt_key_t *ddk = &dde->dde_key;
1257 ddt_phys_t *ddp = dde->dde_phys;
1259 zbookmark_phys_t zb = { 0 };
1261 if (scn->scn_phys.scn_state != DSS_SCANNING)
1264 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1265 if (ddp->ddp_phys_birth == 0 ||
1266 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
1268 ddt_bp_create(checksum, ddk, ddp, &bp);
1270 scn->scn_visited_this_txg++;
1271 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1276 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1278 dsl_pool_t *dp = scn->scn_dp;
1282 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1283 scn->scn_phys.scn_ddt_class_max) {
1284 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1285 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1286 dsl_scan_ddt(scn, tx);
1287 if (scn->scn_pausing)
1291 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1292 /* First do the MOS & ORIGIN */
1294 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1295 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1296 dsl_scan_visit_rootbp(scn, NULL,
1297 &dp->dp_meta_rootbp, tx);
1298 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1299 if (scn->scn_pausing)
1302 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1303 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1304 enqueue_cb, tx, DS_FIND_CHILDREN));
1306 dsl_scan_visitds(scn,
1307 dp->dp_origin_snap->ds_object, tx);
1309 ASSERT(!scn->scn_pausing);
1310 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
1311 ZB_DESTROYED_OBJSET) {
1313 * If we were paused, continue from here. Note if the
1314 * ds we were paused on was deleted, the zb_objset may
1315 * be -1, so we will skip this and find a new objset
1318 dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
1319 if (scn->scn_pausing)
1324 * In case we were paused right at the end of the ds, zero the
1325 * bookmark so we don't think that we're still trying to resume.
1327 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_phys_t));
1329 /* keep pulling things out of the zap-object-as-queue */
1330 while (zap_cursor_init(&zc, dp->dp_meta_objset,
1331 scn->scn_phys.scn_queue_obj),
1332 zap_cursor_retrieve(&zc, &za) == 0) {
1336 dsobj = strtonum(za.za_name, NULL);
1337 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1338 scn->scn_phys.scn_queue_obj, dsobj, tx));
1340 /* Set up min/max txg */
1341 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1342 if (za.za_first_integer != 0) {
1343 scn->scn_phys.scn_cur_min_txg =
1344 MAX(scn->scn_phys.scn_min_txg,
1345 za.za_first_integer);
1347 scn->scn_phys.scn_cur_min_txg =
1348 MAX(scn->scn_phys.scn_min_txg,
1349 dsl_dataset_phys(ds)->ds_prev_snap_txg);
1351 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
1352 dsl_dataset_rele(ds, FTAG);
1354 dsl_scan_visitds(scn, dsobj, tx);
1355 zap_cursor_fini(&zc);
1356 if (scn->scn_pausing)
1359 zap_cursor_fini(&zc);
1363 dsl_scan_free_should_pause(dsl_scan_t *scn)
1365 uint64_t elapsed_nanosecs;
1370 if (scn->scn_visited_this_txg >= zfs_free_max_blocks)
1373 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
1374 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
1375 (NSEC2MSEC(elapsed_nanosecs) > zfs_free_min_time_ms &&
1376 txg_sync_waiting(scn->scn_dp)) ||
1377 spa_shutting_down(scn->scn_dp->dp_spa));
1381 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1383 dsl_scan_t *scn = arg;
1385 if (!scn->scn_is_bptree ||
1386 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
1387 if (dsl_scan_free_should_pause(scn))
1388 return (SET_ERROR(ERESTART));
1391 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
1392 dmu_tx_get_txg(tx), bp, BP_GET_PSIZE(bp), 0));
1393 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
1394 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
1395 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
1396 scn->scn_visited_this_txg++;
1401 dsl_scan_active(dsl_scan_t *scn)
1403 spa_t *spa = scn->scn_dp->dp_spa;
1404 uint64_t used = 0, comp, uncomp;
1406 if (spa->spa_load_state != SPA_LOAD_NONE)
1408 if (spa_shutting_down(spa))
1410 if (scn->scn_phys.scn_state == DSS_SCANNING ||
1411 (scn->scn_async_destroying && !scn->scn_async_stalled))
1414 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1415 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
1416 &used, &comp, &uncomp);
1422 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
1424 dsl_scan_t *scn = dp->dp_scan;
1425 spa_t *spa = dp->dp_spa;
1429 * Check for scn_restart_txg before checking spa_load_state, so
1430 * that we can restart an old-style scan while the pool is being
1431 * imported (see dsl_scan_init).
1433 if (scn->scn_restart_txg != 0 &&
1434 scn->scn_restart_txg <= tx->tx_txg) {
1435 pool_scan_func_t func = POOL_SCAN_SCRUB;
1436 dsl_scan_done(scn, B_FALSE, tx);
1437 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
1438 func = POOL_SCAN_RESILVER;
1439 zfs_dbgmsg("restarting scan func=%u txg=%llu",
1441 dsl_scan_setup_sync(&func, tx);
1445 * If the scan is inactive due to a stalled async destroy, try again.
1447 if ((!scn->scn_async_stalled && !dsl_scan_active(scn)) ||
1448 spa_sync_pass(dp->dp_spa) > 1)
1451 scn->scn_visited_this_txg = 0;
1452 scn->scn_pausing = B_FALSE;
1453 scn->scn_sync_start_time = gethrtime();
1454 spa->spa_scrub_active = B_TRUE;
1457 * First process the async destroys. If we pause, don't do
1458 * any scrubbing or resilvering. This ensures that there are no
1459 * async destroys while we are scanning, so the scan code doesn't
1460 * have to worry about traversing it. It is also faster to free the
1461 * blocks than to scrub them.
1463 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1464 scn->scn_is_bptree = B_FALSE;
1465 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1466 NULL, ZIO_FLAG_MUSTSUCCEED);
1467 err = bpobj_iterate(&dp->dp_free_bpobj,
1468 dsl_scan_free_block_cb, scn, tx);
1469 VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
1471 if (err != 0 && err != ERESTART)
1472 zfs_panic_recover("error %u from bpobj_iterate()", err);
1475 if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) {
1476 ASSERT(scn->scn_async_destroying);
1477 scn->scn_is_bptree = B_TRUE;
1478 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1479 NULL, ZIO_FLAG_MUSTSUCCEED);
1480 err = bptree_iterate(dp->dp_meta_objset,
1481 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx);
1482 VERIFY0(zio_wait(scn->scn_zio_root));
1484 if (err == EIO || err == ECKSUM) {
1486 } else if (err != 0 && err != ERESTART) {
1487 zfs_panic_recover("error %u from "
1488 "traverse_dataset_destroyed()", err);
1491 if (bptree_is_empty(dp->dp_meta_objset, dp->dp_bptree_obj)) {
1492 /* finished; deactivate async destroy feature */
1493 spa_feature_decr(spa, SPA_FEATURE_ASYNC_DESTROY, tx);
1494 ASSERT(!spa_feature_is_active(spa,
1495 SPA_FEATURE_ASYNC_DESTROY));
1496 VERIFY0(zap_remove(dp->dp_meta_objset,
1497 DMU_POOL_DIRECTORY_OBJECT,
1498 DMU_POOL_BPTREE_OBJ, tx));
1499 VERIFY0(bptree_free(dp->dp_meta_objset,
1500 dp->dp_bptree_obj, tx));
1501 dp->dp_bptree_obj = 0;
1502 scn->scn_async_destroying = B_FALSE;
1503 scn->scn_async_stalled = B_FALSE;
1506 * If we didn't make progress, mark the async
1507 * destroy as stalled, so that we will not initiate
1508 * a spa_sync() on its behalf. Note that we only
1509 * check this if we are not finished, because if the
1510 * bptree had no blocks for us to visit, we can
1511 * finish without "making progress".
1513 scn->scn_async_stalled =
1514 (scn->scn_visited_this_txg == 0);
1517 if (scn->scn_visited_this_txg) {
1518 zfs_dbgmsg("freed %llu blocks in %llums from "
1519 "free_bpobj/bptree txg %llu; err=%d",
1520 (longlong_t)scn->scn_visited_this_txg,
1522 NSEC2MSEC(gethrtime() - scn->scn_sync_start_time),
1523 (longlong_t)tx->tx_txg, err);
1524 scn->scn_visited_this_txg = 0;
1527 * Write out changes to the DDT that may be required as a
1528 * result of the blocks freed. This ensures that the DDT
1529 * is clean when a scrub/resilver runs.
1531 ddt_sync(spa, tx->tx_txg);
1535 if (!scn->scn_async_destroying && zfs_free_leak_on_eio &&
1536 (dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes != 0 ||
1537 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes != 0 ||
1538 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes != 0)) {
1540 * We have finished background destroying, but there is still
1541 * some space left in the dp_free_dir. Transfer this leaked
1542 * space to the dp_leak_dir.
1544 if (dp->dp_leak_dir == NULL) {
1545 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
1546 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
1548 VERIFY0(dsl_pool_open_special_dir(dp,
1549 LEAK_DIR_NAME, &dp->dp_leak_dir));
1550 rrw_exit(&dp->dp_config_rwlock, FTAG);
1552 dsl_dir_diduse_space(dp->dp_leak_dir, DD_USED_HEAD,
1553 dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
1554 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
1555 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
1556 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
1557 -dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
1558 -dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
1559 -dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
1561 if (!scn->scn_async_destroying) {
1562 /* finished; verify that space accounting went to zero */
1563 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes);
1564 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes);
1565 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes);
1568 if (scn->scn_phys.scn_state != DSS_SCANNING)
1571 if (scn->scn_done_txg == tx->tx_txg) {
1572 ASSERT(!scn->scn_pausing);
1573 /* finished with scan. */
1574 zfs_dbgmsg("txg %llu scan complete", tx->tx_txg);
1575 dsl_scan_done(scn, B_TRUE, tx);
1576 ASSERT3U(spa->spa_scrub_inflight, ==, 0);
1577 dsl_scan_sync_state(scn, tx);
1581 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1582 scn->scn_phys.scn_ddt_class_max) {
1583 zfs_dbgmsg("doing scan sync txg %llu; "
1584 "ddt bm=%llu/%llu/%llu/%llx",
1585 (longlong_t)tx->tx_txg,
1586 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1587 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1588 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1589 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1590 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
1591 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
1592 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
1593 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
1595 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
1596 (longlong_t)tx->tx_txg,
1597 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
1598 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
1599 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
1600 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
1603 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1604 NULL, ZIO_FLAG_CANFAIL);
1605 dsl_pool_config_enter(dp, FTAG);
1606 dsl_scan_visit(scn, tx);
1607 dsl_pool_config_exit(dp, FTAG);
1608 (void) zio_wait(scn->scn_zio_root);
1609 scn->scn_zio_root = NULL;
1611 zfs_dbgmsg("visited %llu blocks in %llums",
1612 (longlong_t)scn->scn_visited_this_txg,
1613 (longlong_t)NSEC2MSEC(gethrtime() - scn->scn_sync_start_time));
1615 if (!scn->scn_pausing) {
1616 scn->scn_done_txg = tx->tx_txg + 1;
1617 zfs_dbgmsg("txg %llu traversal complete, waiting till txg %llu",
1618 tx->tx_txg, scn->scn_done_txg);
1621 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
1622 mutex_enter(&spa->spa_scrub_lock);
1623 while (spa->spa_scrub_inflight > 0) {
1624 cv_wait(&spa->spa_scrub_io_cv,
1625 &spa->spa_scrub_lock);
1627 mutex_exit(&spa->spa_scrub_lock);
1630 dsl_scan_sync_state(scn, tx);
1634 * This will start a new scan, or restart an existing one.
1637 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
1641 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1642 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1644 txg = dmu_tx_get_txg(tx);
1645 dp->dp_scan->scn_restart_txg = txg;
1648 dp->dp_scan->scn_restart_txg = txg;
1650 zfs_dbgmsg("restarting resilver txg=%llu", txg);
1654 dsl_scan_resilvering(dsl_pool_t *dp)
1656 return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
1657 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
1665 count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
1670 * If we resume after a reboot, zab will be NULL; don't record
1671 * incomplete stats in that case.
1676 for (i = 0; i < 4; i++) {
1677 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
1678 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
1679 if (t & DMU_OT_NEWTYPE)
1681 zfs_blkstat_t *zb = &zab->zab_type[l][t];
1685 zb->zb_asize += BP_GET_ASIZE(bp);
1686 zb->zb_lsize += BP_GET_LSIZE(bp);
1687 zb->zb_psize += BP_GET_PSIZE(bp);
1688 zb->zb_gangs += BP_COUNT_GANG(bp);
1690 switch (BP_GET_NDVAS(bp)) {
1692 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1693 DVA_GET_VDEV(&bp->blk_dva[1]))
1694 zb->zb_ditto_2_of_2_samevdev++;
1697 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1698 DVA_GET_VDEV(&bp->blk_dva[1])) +
1699 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1700 DVA_GET_VDEV(&bp->blk_dva[2])) +
1701 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
1702 DVA_GET_VDEV(&bp->blk_dva[2]));
1704 zb->zb_ditto_2_of_3_samevdev++;
1705 else if (equal == 3)
1706 zb->zb_ditto_3_of_3_samevdev++;
1713 dsl_scan_scrub_done(zio_t *zio)
1715 spa_t *spa = zio->io_spa;
1717 zio_data_buf_free(zio->io_data, zio->io_size);
1719 mutex_enter(&spa->spa_scrub_lock);
1720 spa->spa_scrub_inflight--;
1721 cv_broadcast(&spa->spa_scrub_io_cv);
1723 if (zio->io_error && (zio->io_error != ECKSUM ||
1724 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
1725 spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
1727 mutex_exit(&spa->spa_scrub_lock);
1731 dsl_scan_scrub_cb(dsl_pool_t *dp,
1732 const blkptr_t *bp, const zbookmark_phys_t *zb)
1734 dsl_scan_t *scn = dp->dp_scan;
1735 size_t size = BP_GET_PSIZE(bp);
1736 spa_t *spa = dp->dp_spa;
1737 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
1739 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
1740 unsigned int scan_delay = 0;
1742 if (phys_birth <= scn->scn_phys.scn_min_txg ||
1743 phys_birth >= scn->scn_phys.scn_max_txg)
1746 count_block(dp->dp_blkstats, bp);
1748 if (BP_IS_EMBEDDED(bp))
1751 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
1752 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
1753 zio_flags |= ZIO_FLAG_SCRUB;
1755 scan_delay = zfs_scrub_delay;
1757 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
1758 zio_flags |= ZIO_FLAG_RESILVER;
1760 scan_delay = zfs_resilver_delay;
1763 /* If it's an intent log block, failure is expected. */
1764 if (zb->zb_level == ZB_ZIL_LEVEL)
1765 zio_flags |= ZIO_FLAG_SPECULATIVE;
1767 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
1768 vdev_t *vd = vdev_lookup_top(spa,
1769 DVA_GET_VDEV(&bp->blk_dva[d]));
1772 * Keep track of how much data we've examined so that
1773 * zpool(1M) status can make useful progress reports.
1775 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
1776 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
1778 /* if it's a resilver, this may not be in the target range */
1780 if (DVA_GET_GANG(&bp->blk_dva[d])) {
1782 * Gang members may be spread across multiple
1783 * vdevs, so the best estimate we have is the
1784 * scrub range, which has already been checked.
1785 * XXX -- it would be better to change our
1786 * allocation policy to ensure that all
1787 * gang members reside on the same vdev.
1791 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
1797 if (needs_io && !zfs_no_scrub_io) {
1798 vdev_t *rvd = spa->spa_root_vdev;
1799 uint64_t maxinflight = rvd->vdev_children *
1800 MAX(zfs_top_maxinflight, 1);
1801 void *data = zio_data_buf_alloc(size);
1803 mutex_enter(&spa->spa_scrub_lock);
1804 while (spa->spa_scrub_inflight >= maxinflight)
1805 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1806 spa->spa_scrub_inflight++;
1807 mutex_exit(&spa->spa_scrub_lock);
1810 * If we're seeing recent (zfs_scan_idle) "important" I/Os
1811 * then throttle our workload to limit the impact of a scan.
1813 if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
1814 delay(MAX((int)scan_delay, 0));
1816 zio_nowait(zio_read(NULL, spa, bp, data, size,
1817 dsl_scan_scrub_done, NULL, ZIO_PRIORITY_SCRUB,
1821 /* do not relocate this block */
1826 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
1828 spa_t *spa = dp->dp_spa;
1831 * Purge all vdev caches and probe all devices. We do this here
1832 * rather than in sync context because this requires a writer lock
1833 * on the spa_config lock, which we can't do from sync context. The
1834 * spa_scrub_reopen flag indicates that vdev_open() should not
1835 * attempt to start another scrub.
1837 spa_vdev_state_enter(spa, SCL_NONE);
1838 spa->spa_scrub_reopen = B_TRUE;
1839 vdev_reopen(spa->spa_root_vdev);
1840 spa->spa_scrub_reopen = B_FALSE;
1841 (void) spa_vdev_state_exit(spa, NULL, 0);
1843 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
1844 dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_NONE));