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, 2018 by Delphix. All rights reserved.
24 * Copyright 2016 Gary Mills
25 * Copyright (c) 2017, 2019, Datto Inc. All rights reserved.
26 * Copyright (c) 2015, Nexenta Systems, Inc. All rights reserved.
27 * Copyright 2019 Joyent, Inc.
30 #include <sys/dsl_scan.h>
31 #include <sys/dsl_pool.h>
32 #include <sys/dsl_dataset.h>
33 #include <sys/dsl_prop.h>
34 #include <sys/dsl_dir.h>
35 #include <sys/dsl_synctask.h>
36 #include <sys/dnode.h>
37 #include <sys/dmu_tx.h>
38 #include <sys/dmu_objset.h>
42 #include <sys/zfs_context.h>
43 #include <sys/fs/zfs.h>
44 #include <sys/zfs_znode.h>
45 #include <sys/spa_impl.h>
46 #include <sys/vdev_impl.h>
47 #include <sys/zil_impl.h>
48 #include <sys/zio_checksum.h>
51 #include <sys/sa_impl.h>
52 #include <sys/zfeature.h>
54 #include <sys/range_tree.h>
56 #include <sys/zfs_vfsops.h>
60 * Grand theory statement on scan queue sorting
62 * Scanning is implemented by recursively traversing all indirection levels
63 * in an object and reading all blocks referenced from said objects. This
64 * results in us approximately traversing the object from lowest logical
65 * offset to the highest. For best performance, we would want the logical
66 * blocks to be physically contiguous. However, this is frequently not the
67 * case with pools given the allocation patterns of copy-on-write filesystems.
68 * So instead, we put the I/Os into a reordering queue and issue them in a
69 * way that will most benefit physical disks (LBA-order).
73 * Ideally, we would want to scan all metadata and queue up all block I/O
74 * prior to starting to issue it, because that allows us to do an optimal
75 * sorting job. This can however consume large amounts of memory. Therefore
76 * we continuously monitor the size of the queues and constrain them to 5%
77 * (zfs_scan_mem_lim_fact) of physmem. If the queues grow larger than this
78 * limit, we clear out a few of the largest extents at the head of the queues
79 * to make room for more scanning. Hopefully, these extents will be fairly
80 * large and contiguous, allowing us to approach sequential I/O throughput
81 * even without a fully sorted tree.
83 * Metadata scanning takes place in dsl_scan_visit(), which is called from
84 * dsl_scan_sync() every spa_sync(). If we have either fully scanned all
85 * metadata on the pool, or we need to make room in memory because our
86 * queues are too large, dsl_scan_visit() is postponed and
87 * scan_io_queues_run() is called from dsl_scan_sync() instead. This implies
88 * that metadata scanning and queued I/O issuing are mutually exclusive. This
89 * allows us to provide maximum sequential I/O throughput for the majority of
90 * I/O's issued since sequential I/O performance is significantly negatively
91 * impacted if it is interleaved with random I/O.
93 * Implementation Notes
95 * One side effect of the queued scanning algorithm is that the scanning code
96 * needs to be notified whenever a block is freed. This is needed to allow
97 * the scanning code to remove these I/Os from the issuing queue. Additionally,
98 * we do not attempt to queue gang blocks to be issued sequentially since this
99 * is very hard to do and would have an extremely limited performance benefit.
100 * Instead, we simply issue gang I/Os as soon as we find them using the legacy
103 * Backwards compatibility
105 * This new algorithm is backwards compatible with the legacy on-disk data
106 * structures (and therefore does not require a new feature flag).
107 * Periodically during scanning (see zfs_scan_checkpoint_intval), the scan
108 * will stop scanning metadata (in logical order) and wait for all outstanding
109 * sorted I/O to complete. Once this is done, we write out a checkpoint
110 * bookmark, indicating that we have scanned everything logically before it.
111 * If the pool is imported on a machine without the new sorting algorithm,
112 * the scan simply resumes from the last checkpoint using the legacy algorithm.
115 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *,
116 const zbookmark_phys_t *);
118 static scan_cb_t dsl_scan_scrub_cb;
120 static int scan_ds_queue_compare(const void *a, const void *b);
121 static int scan_prefetch_queue_compare(const void *a, const void *b);
122 static void scan_ds_queue_clear(dsl_scan_t *scn);
123 static void scan_ds_prefetch_queue_clear(dsl_scan_t *scn);
124 static boolean_t scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj,
126 static void scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg);
127 static void scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj);
128 static void scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx);
129 static uint64_t dsl_scan_count_leaves(vdev_t *vd);
131 extern int zfs_vdev_async_write_active_min_dirty_percent;
134 * By default zfs will check to ensure it is not over the hard memory
135 * limit before each txg. If finer-grained control of this is needed
136 * this value can be set to 1 to enable checking before scanning each
139 int zfs_scan_strict_mem_lim = B_FALSE;
142 * Maximum number of parallelly executed bytes per leaf vdev. We attempt
143 * to strike a balance here between keeping the vdev queues full of I/Os
144 * at all times and not overflowing the queues to cause long latency,
145 * which would cause long txg sync times. No matter what, we will not
146 * overload the drives with I/O, since that is protected by
147 * zfs_vdev_scrub_max_active.
149 unsigned long zfs_scan_vdev_limit = 4 << 20;
151 int zfs_scan_issue_strategy = 0;
152 int zfs_scan_legacy = B_FALSE; /* don't queue & sort zios, go direct */
153 unsigned long zfs_scan_max_ext_gap = 2 << 20; /* in bytes */
156 * fill_weight is non-tunable at runtime, so we copy it at module init from
157 * zfs_scan_fill_weight. Runtime adjustments to zfs_scan_fill_weight would
158 * break queue sorting.
160 int zfs_scan_fill_weight = 3;
161 static uint64_t fill_weight;
163 /* See dsl_scan_should_clear() for details on the memory limit tunables */
164 uint64_t zfs_scan_mem_lim_min = 16 << 20; /* bytes */
165 uint64_t zfs_scan_mem_lim_soft_max = 128 << 20; /* bytes */
166 int zfs_scan_mem_lim_fact = 20; /* fraction of physmem */
167 int zfs_scan_mem_lim_soft_fact = 20; /* fraction of mem lim above */
169 int zfs_scrub_min_time_ms = 1000; /* min millisecs to scrub per txg */
170 int zfs_obsolete_min_time_ms = 500; /* min millisecs to obsolete per txg */
171 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
172 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
173 int zfs_scan_checkpoint_intval = 7200; /* in seconds */
174 int zfs_scan_suspend_progress = 0; /* set to prevent scans from progressing */
175 int zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
176 int zfs_no_scrub_prefetch = B_FALSE; /* set to disable scrub prefetch */
177 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
178 /* max number of blocks to free in a single TXG */
179 unsigned long zfs_async_block_max_blocks = ULONG_MAX;
180 /* max number of dedup blocks to free in a single TXG */
181 unsigned long zfs_max_async_dedup_frees = 100000;
183 int zfs_resilver_disable_defer = 0; /* set to disable resilver deferring */
186 * We wait a few txgs after importing a pool to begin scanning so that
187 * the import / mounting code isn't held up by scrub / resilver IO.
188 * Unfortunately, it is a bit difficult to determine exactly how long
189 * this will take since userspace will trigger fs mounts asynchronously
190 * and the kernel will create zvol minors asynchronously. As a result,
191 * the value provided here is a bit arbitrary, but represents a
192 * reasonable estimate of how many txgs it will take to finish fully
195 #define SCAN_IMPORT_WAIT_TXGS 5
197 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
198 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
199 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
202 * Enable/disable the processing of the free_bpobj object.
204 int zfs_free_bpobj_enabled = 1;
206 /* the order has to match pool_scan_type */
207 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
209 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
210 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
213 /* In core node for the scn->scn_queue. Represents a dataset to be scanned */
221 * This controls what conditions are placed on dsl_scan_sync_state():
222 * SYNC_OPTIONAL) write out scn_phys iff scn_bytes_pending == 0
223 * SYNC_MANDATORY) write out scn_phys always. scn_bytes_pending must be 0.
224 * SYNC_CACHED) if scn_bytes_pending == 0, write out scn_phys. Otherwise
225 * write out the scn_phys_cached version.
226 * See dsl_scan_sync_state for details.
235 * This struct represents the minimum information needed to reconstruct a
236 * zio for sequential scanning. This is useful because many of these will
237 * accumulate in the sequential IO queues before being issued, so saving
238 * memory matters here.
240 typedef struct scan_io {
241 /* fields from blkptr_t */
242 uint64_t sio_blk_prop;
243 uint64_t sio_phys_birth;
245 zio_cksum_t sio_cksum;
246 uint32_t sio_nr_dvas;
248 /* fields from zio_t */
250 zbookmark_phys_t sio_zb;
252 /* members for queue sorting */
254 avl_node_t sio_addr_node; /* link into issuing queue */
255 list_node_t sio_list_node; /* link for issuing to disk */
259 * There may be up to SPA_DVAS_PER_BP DVAs here from the bp,
260 * depending on how many were in the original bp. Only the
261 * first DVA is really used for sorting and issuing purposes.
262 * The other DVAs (if provided) simply exist so that the zio
263 * layer can find additional copies to repair from in the
264 * event of an error. This array must go at the end of the
265 * struct to allow this for the variable number of elements.
270 #define SIO_SET_OFFSET(sio, x) DVA_SET_OFFSET(&(sio)->sio_dva[0], x)
271 #define SIO_SET_ASIZE(sio, x) DVA_SET_ASIZE(&(sio)->sio_dva[0], x)
272 #define SIO_GET_OFFSET(sio) DVA_GET_OFFSET(&(sio)->sio_dva[0])
273 #define SIO_GET_ASIZE(sio) DVA_GET_ASIZE(&(sio)->sio_dva[0])
274 #define SIO_GET_END_OFFSET(sio) \
275 (SIO_GET_OFFSET(sio) + SIO_GET_ASIZE(sio))
276 #define SIO_GET_MUSED(sio) \
277 (sizeof (scan_io_t) + ((sio)->sio_nr_dvas * sizeof (dva_t)))
279 struct dsl_scan_io_queue {
280 dsl_scan_t *q_scn; /* associated dsl_scan_t */
281 vdev_t *q_vd; /* top-level vdev that this queue represents */
283 /* trees used for sorting I/Os and extents of I/Os */
284 range_tree_t *q_exts_by_addr;
285 zfs_btree_t q_exts_by_size;
286 avl_tree_t q_sios_by_addr;
287 uint64_t q_sio_memused;
289 /* members for zio rate limiting */
290 uint64_t q_maxinflight_bytes;
291 uint64_t q_inflight_bytes;
292 kcondvar_t q_zio_cv; /* used under vd->vdev_scan_io_queue_lock */
294 /* per txg statistics */
295 uint64_t q_total_seg_size_this_txg;
296 uint64_t q_segs_this_txg;
297 uint64_t q_total_zio_size_this_txg;
298 uint64_t q_zios_this_txg;
301 /* private data for dsl_scan_prefetch_cb() */
302 typedef struct scan_prefetch_ctx {
303 zfs_refcount_t spc_refcnt; /* refcount for memory management */
304 dsl_scan_t *spc_scn; /* dsl_scan_t for the pool */
305 boolean_t spc_root; /* is this prefetch for an objset? */
306 uint8_t spc_indblkshift; /* dn_indblkshift of current dnode */
307 uint16_t spc_datablkszsec; /* dn_idatablkszsec of current dnode */
308 } scan_prefetch_ctx_t;
310 /* private data for dsl_scan_prefetch() */
311 typedef struct scan_prefetch_issue_ctx {
312 avl_node_t spic_avl_node; /* link into scn->scn_prefetch_queue */
313 scan_prefetch_ctx_t *spic_spc; /* spc for the callback */
314 blkptr_t spic_bp; /* bp to prefetch */
315 zbookmark_phys_t spic_zb; /* bookmark to prefetch */
316 } scan_prefetch_issue_ctx_t;
318 static void scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
319 const zbookmark_phys_t *zb, dsl_scan_io_queue_t *queue);
320 static void scan_io_queue_insert_impl(dsl_scan_io_queue_t *queue,
323 static dsl_scan_io_queue_t *scan_io_queue_create(vdev_t *vd);
324 static void scan_io_queues_destroy(dsl_scan_t *scn);
326 static kmem_cache_t *sio_cache[SPA_DVAS_PER_BP];
328 /* sio->sio_nr_dvas must be set so we know which cache to free from */
330 sio_free(scan_io_t *sio)
332 ASSERT3U(sio->sio_nr_dvas, >, 0);
333 ASSERT3U(sio->sio_nr_dvas, <=, SPA_DVAS_PER_BP);
335 kmem_cache_free(sio_cache[sio->sio_nr_dvas - 1], sio);
338 /* It is up to the caller to set sio->sio_nr_dvas for freeing */
340 sio_alloc(unsigned short nr_dvas)
342 ASSERT3U(nr_dvas, >, 0);
343 ASSERT3U(nr_dvas, <=, SPA_DVAS_PER_BP);
345 return (kmem_cache_alloc(sio_cache[nr_dvas - 1], KM_SLEEP));
352 * This is used in ext_size_compare() to weight segments
353 * based on how sparse they are. This cannot be changed
354 * mid-scan and the tree comparison functions don't currently
355 * have a mechanism for passing additional context to the
356 * compare functions. Thus we store this value globally and
357 * we only allow it to be set at module initialization time
359 fill_weight = zfs_scan_fill_weight;
361 for (int i = 0; i < SPA_DVAS_PER_BP; i++) {
364 (void) snprintf(name, sizeof (name), "sio_cache_%d", i);
365 sio_cache[i] = kmem_cache_create(name,
366 (sizeof (scan_io_t) + ((i + 1) * sizeof (dva_t))),
367 0, NULL, NULL, NULL, NULL, NULL, 0);
374 for (int i = 0; i < SPA_DVAS_PER_BP; i++) {
375 kmem_cache_destroy(sio_cache[i]);
379 static inline boolean_t
380 dsl_scan_is_running(const dsl_scan_t *scn)
382 return (scn->scn_phys.scn_state == DSS_SCANNING);
386 dsl_scan_resilvering(dsl_pool_t *dp)
388 return (dsl_scan_is_running(dp->dp_scan) &&
389 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
393 sio2bp(const scan_io_t *sio, blkptr_t *bp)
395 bzero(bp, sizeof (*bp));
396 bp->blk_prop = sio->sio_blk_prop;
397 bp->blk_phys_birth = sio->sio_phys_birth;
398 bp->blk_birth = sio->sio_birth;
399 bp->blk_fill = 1; /* we always only work with data pointers */
400 bp->blk_cksum = sio->sio_cksum;
402 ASSERT3U(sio->sio_nr_dvas, >, 0);
403 ASSERT3U(sio->sio_nr_dvas, <=, SPA_DVAS_PER_BP);
405 bcopy(sio->sio_dva, bp->blk_dva, sio->sio_nr_dvas * sizeof (dva_t));
409 bp2sio(const blkptr_t *bp, scan_io_t *sio, int dva_i)
411 sio->sio_blk_prop = bp->blk_prop;
412 sio->sio_phys_birth = bp->blk_phys_birth;
413 sio->sio_birth = bp->blk_birth;
414 sio->sio_cksum = bp->blk_cksum;
415 sio->sio_nr_dvas = BP_GET_NDVAS(bp);
418 * Copy the DVAs to the sio. We need all copies of the block so
419 * that the self healing code can use the alternate copies if the
420 * first is corrupted. We want the DVA at index dva_i to be first
421 * in the sio since this is the primary one that we want to issue.
423 for (int i = 0, j = dva_i; i < sio->sio_nr_dvas; i++, j++) {
424 sio->sio_dva[i] = bp->blk_dva[j % sio->sio_nr_dvas];
429 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
433 spa_t *spa = dp->dp_spa;
436 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
440 * It's possible that we're resuming a scan after a reboot so
441 * make sure that the scan_async_destroying flag is initialized
444 ASSERT(!scn->scn_async_destroying);
445 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
446 SPA_FEATURE_ASYNC_DESTROY);
449 * Calculate the max number of in-flight bytes for pool-wide
450 * scanning operations (minimum 1MB). Limits for the issuing
451 * phase are done per top-level vdev and are handled separately.
453 scn->scn_maxinflight_bytes = MAX(zfs_scan_vdev_limit *
454 dsl_scan_count_leaves(spa->spa_root_vdev), 1ULL << 20);
456 avl_create(&scn->scn_queue, scan_ds_queue_compare, sizeof (scan_ds_t),
457 offsetof(scan_ds_t, sds_node));
458 avl_create(&scn->scn_prefetch_queue, scan_prefetch_queue_compare,
459 sizeof (scan_prefetch_issue_ctx_t),
460 offsetof(scan_prefetch_issue_ctx_t, spic_avl_node));
462 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
463 "scrub_func", sizeof (uint64_t), 1, &f);
466 * There was an old-style scrub in progress. Restart a
467 * new-style scrub from the beginning.
469 scn->scn_restart_txg = txg;
470 zfs_dbgmsg("old-style scrub was in progress; "
471 "restarting new-style scrub in txg %llu",
472 (longlong_t)scn->scn_restart_txg);
475 * Load the queue obj from the old location so that it
476 * can be freed by dsl_scan_done().
478 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
479 "scrub_queue", sizeof (uint64_t), 1,
480 &scn->scn_phys.scn_queue_obj);
482 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
483 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
486 * Detect if the pool contains the signature of #2094. If it
487 * does properly update the scn->scn_phys structure and notify
488 * the administrator by setting an errata for the pool.
490 if (err == EOVERFLOW) {
491 uint64_t zaptmp[SCAN_PHYS_NUMINTS + 1];
492 VERIFY3S(SCAN_PHYS_NUMINTS, ==, 24);
493 VERIFY3S(offsetof(dsl_scan_phys_t, scn_flags), ==,
494 (23 * sizeof (uint64_t)));
496 err = zap_lookup(dp->dp_meta_objset,
497 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SCAN,
498 sizeof (uint64_t), SCAN_PHYS_NUMINTS + 1, &zaptmp);
500 uint64_t overflow = zaptmp[SCAN_PHYS_NUMINTS];
502 if (overflow & ~DSL_SCAN_FLAGS_MASK ||
503 scn->scn_async_destroying) {
505 ZPOOL_ERRATA_ZOL_2094_ASYNC_DESTROY;
509 bcopy(zaptmp, &scn->scn_phys,
510 SCAN_PHYS_NUMINTS * sizeof (uint64_t));
511 scn->scn_phys.scn_flags = overflow;
513 /* Required scrub already in progress. */
514 if (scn->scn_phys.scn_state == DSS_FINISHED ||
515 scn->scn_phys.scn_state == DSS_CANCELED)
517 ZPOOL_ERRATA_ZOL_2094_SCRUB;
527 * We might be restarting after a reboot, so jump the issued
528 * counter to how far we've scanned. We know we're consistent
531 scn->scn_issued_before_pass = scn->scn_phys.scn_examined;
533 if (dsl_scan_is_running(scn) &&
534 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
536 * A new-type scrub was in progress on an old
537 * pool, and the pool was accessed by old
538 * software. Restart from the beginning, since
539 * the old software may have changed the pool in
542 scn->scn_restart_txg = txg;
543 zfs_dbgmsg("new-style scrub was modified "
544 "by old software; restarting in txg %llu",
545 (longlong_t)scn->scn_restart_txg);
546 } else if (dsl_scan_resilvering(dp)) {
548 * If a resilver is in progress and there are already
549 * errors, restart it instead of finishing this scan and
550 * then restarting it. If there haven't been any errors
551 * then remember that the incore DTL is valid.
553 if (scn->scn_phys.scn_errors > 0) {
554 scn->scn_restart_txg = txg;
555 zfs_dbgmsg("resilver can't excise DTL_MISSING "
556 "when finished; restarting in txg %llu",
557 (u_longlong_t)scn->scn_restart_txg);
559 /* it's safe to excise DTL when finished */
560 spa->spa_scrub_started = B_TRUE;
565 bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
567 /* reload the queue into the in-core state */
568 if (scn->scn_phys.scn_queue_obj != 0) {
572 for (zap_cursor_init(&zc, dp->dp_meta_objset,
573 scn->scn_phys.scn_queue_obj);
574 zap_cursor_retrieve(&zc, &za) == 0;
575 (void) zap_cursor_advance(&zc)) {
576 scan_ds_queue_insert(scn,
577 zfs_strtonum(za.za_name, NULL),
578 za.za_first_integer);
580 zap_cursor_fini(&zc);
583 spa_scan_stat_init(spa);
588 dsl_scan_fini(dsl_pool_t *dp)
590 if (dp->dp_scan != NULL) {
591 dsl_scan_t *scn = dp->dp_scan;
593 if (scn->scn_taskq != NULL)
594 taskq_destroy(scn->scn_taskq);
596 scan_ds_queue_clear(scn);
597 avl_destroy(&scn->scn_queue);
598 scan_ds_prefetch_queue_clear(scn);
599 avl_destroy(&scn->scn_prefetch_queue);
601 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
607 dsl_scan_restarting(dsl_scan_t *scn, dmu_tx_t *tx)
609 return (scn->scn_restart_txg != 0 &&
610 scn->scn_restart_txg <= tx->tx_txg);
614 dsl_scan_resilver_scheduled(dsl_pool_t *dp)
616 return ((dp->dp_scan && dp->dp_scan->scn_restart_txg != 0) ||
617 (spa_async_tasks(dp->dp_spa) & SPA_ASYNC_RESILVER));
621 dsl_scan_scrubbing(const dsl_pool_t *dp)
623 dsl_scan_phys_t *scn_phys = &dp->dp_scan->scn_phys;
625 return (scn_phys->scn_state == DSS_SCANNING &&
626 scn_phys->scn_func == POOL_SCAN_SCRUB);
630 dsl_scan_is_paused_scrub(const dsl_scan_t *scn)
632 return (dsl_scan_scrubbing(scn->scn_dp) &&
633 scn->scn_phys.scn_flags & DSF_SCRUB_PAUSED);
637 * Writes out a persistent dsl_scan_phys_t record to the pool directory.
638 * Because we can be running in the block sorting algorithm, we do not always
639 * want to write out the record, only when it is "safe" to do so. This safety
640 * condition is achieved by making sure that the sorting queues are empty
641 * (scn_bytes_pending == 0). When this condition is not true, the sync'd state
642 * is inconsistent with how much actual scanning progress has been made. The
643 * kind of sync to be performed is specified by the sync_type argument. If the
644 * sync is optional, we only sync if the queues are empty. If the sync is
645 * mandatory, we do a hard ASSERT to make sure that the queues are empty. The
646 * third possible state is a "cached" sync. This is done in response to:
647 * 1) The dataset that was in the last sync'd dsl_scan_phys_t having been
648 * destroyed, so we wouldn't be able to restart scanning from it.
649 * 2) The snapshot that was in the last sync'd dsl_scan_phys_t having been
650 * superseded by a newer snapshot.
651 * 3) The dataset that was in the last sync'd dsl_scan_phys_t having been
652 * swapped with its clone.
653 * In all cases, a cached sync simply rewrites the last record we've written,
654 * just slightly modified. For the modifications that are performed to the
655 * last written dsl_scan_phys_t, see dsl_scan_ds_destroyed,
656 * dsl_scan_ds_snapshotted and dsl_scan_ds_clone_swapped.
659 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx, state_sync_type_t sync_type)
662 spa_t *spa = scn->scn_dp->dp_spa;
664 ASSERT(sync_type != SYNC_MANDATORY || scn->scn_bytes_pending == 0);
665 if (scn->scn_bytes_pending == 0) {
666 for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
667 vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
668 dsl_scan_io_queue_t *q = vd->vdev_scan_io_queue;
673 mutex_enter(&vd->vdev_scan_io_queue_lock);
674 ASSERT3P(avl_first(&q->q_sios_by_addr), ==, NULL);
675 ASSERT3P(zfs_btree_first(&q->q_exts_by_size, NULL), ==,
677 ASSERT3P(range_tree_first(q->q_exts_by_addr), ==, NULL);
678 mutex_exit(&vd->vdev_scan_io_queue_lock);
681 if (scn->scn_phys.scn_queue_obj != 0)
682 scan_ds_queue_sync(scn, tx);
683 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
684 DMU_POOL_DIRECTORY_OBJECT,
685 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
686 &scn->scn_phys, tx));
687 bcopy(&scn->scn_phys, &scn->scn_phys_cached,
688 sizeof (scn->scn_phys));
690 if (scn->scn_checkpointing)
691 zfs_dbgmsg("finish scan checkpoint");
693 scn->scn_checkpointing = B_FALSE;
694 scn->scn_last_checkpoint = ddi_get_lbolt();
695 } else if (sync_type == SYNC_CACHED) {
696 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
697 DMU_POOL_DIRECTORY_OBJECT,
698 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
699 &scn->scn_phys_cached, tx));
705 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
707 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
708 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
710 if (dsl_scan_is_running(scn) || vdev_rebuild_active(rvd))
711 return (SET_ERROR(EBUSY));
717 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
719 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
720 pool_scan_func_t *funcp = arg;
721 dmu_object_type_t ot = 0;
722 dsl_pool_t *dp = scn->scn_dp;
723 spa_t *spa = dp->dp_spa;
725 ASSERT(!dsl_scan_is_running(scn));
726 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
727 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
728 scn->scn_phys.scn_func = *funcp;
729 scn->scn_phys.scn_state = DSS_SCANNING;
730 scn->scn_phys.scn_min_txg = 0;
731 scn->scn_phys.scn_max_txg = tx->tx_txg;
732 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
733 scn->scn_phys.scn_start_time = gethrestime_sec();
734 scn->scn_phys.scn_errors = 0;
735 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
736 scn->scn_issued_before_pass = 0;
737 scn->scn_restart_txg = 0;
738 scn->scn_done_txg = 0;
739 scn->scn_last_checkpoint = 0;
740 scn->scn_checkpointing = B_FALSE;
741 spa_scan_stat_init(spa);
743 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
744 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
746 /* rewrite all disk labels */
747 vdev_config_dirty(spa->spa_root_vdev);
749 if (vdev_resilver_needed(spa->spa_root_vdev,
750 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
751 nvlist_t *aux = fnvlist_alloc();
752 fnvlist_add_string(aux, ZFS_EV_RESILVER_TYPE,
754 spa_event_notify(spa, NULL, aux,
755 ESC_ZFS_RESILVER_START);
758 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_START);
761 spa->spa_scrub_started = B_TRUE;
763 * If this is an incremental scrub, limit the DDT scrub phase
764 * to just the auto-ditto class (for correctness); the rest
765 * of the scrub should go faster using top-down pruning.
767 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
768 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
771 * When starting a resilver clear any existing rebuild state.
772 * This is required to prevent stale rebuild status from
773 * being reported when a rebuild is run, then a resilver and
774 * finally a scrub. In which case only the scrub status
775 * should be reported by 'zpool status'.
777 if (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) {
778 vdev_t *rvd = spa->spa_root_vdev;
779 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
780 vdev_t *vd = rvd->vdev_child[i];
781 vdev_rebuild_clear_sync(
782 (void *)(uintptr_t)vd->vdev_id, tx);
787 /* back to the generic stuff */
789 if (dp->dp_blkstats == NULL) {
791 vmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
792 mutex_init(&dp->dp_blkstats->zab_lock, NULL,
793 MUTEX_DEFAULT, NULL);
795 bzero(&dp->dp_blkstats->zab_type, sizeof (dp->dp_blkstats->zab_type));
797 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
798 ot = DMU_OT_ZAP_OTHER;
800 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
801 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
803 bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
805 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
807 spa_history_log_internal(spa, "scan setup", tx,
808 "func=%u mintxg=%llu maxtxg=%llu",
809 *funcp, (u_longlong_t)scn->scn_phys.scn_min_txg,
810 (u_longlong_t)scn->scn_phys.scn_max_txg);
814 * Called by the ZFS_IOC_POOL_SCAN ioctl to start a scrub or resilver.
815 * Can also be called to resume a paused scrub.
818 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
820 spa_t *spa = dp->dp_spa;
821 dsl_scan_t *scn = dp->dp_scan;
824 * Purge all vdev caches and probe all devices. We do this here
825 * rather than in sync context because this requires a writer lock
826 * on the spa_config lock, which we can't do from sync context. The
827 * spa_scrub_reopen flag indicates that vdev_open() should not
828 * attempt to start another scrub.
830 spa_vdev_state_enter(spa, SCL_NONE);
831 spa->spa_scrub_reopen = B_TRUE;
832 vdev_reopen(spa->spa_root_vdev);
833 spa->spa_scrub_reopen = B_FALSE;
834 (void) spa_vdev_state_exit(spa, NULL, 0);
836 if (func == POOL_SCAN_RESILVER) {
837 dsl_scan_restart_resilver(spa->spa_dsl_pool, 0);
841 if (func == POOL_SCAN_SCRUB && dsl_scan_is_paused_scrub(scn)) {
842 /* got scrub start cmd, resume paused scrub */
843 int err = dsl_scrub_set_pause_resume(scn->scn_dp,
846 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_RESUME);
847 return (SET_ERROR(ECANCELED));
850 return (SET_ERROR(err));
853 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
854 dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_EXTRA_RESERVED));
859 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
861 static const char *old_names[] = {
863 "scrub_ddt_bookmark",
864 "scrub_ddt_class_max",
873 dsl_pool_t *dp = scn->scn_dp;
874 spa_t *spa = dp->dp_spa;
877 /* Remove any remnants of an old-style scrub. */
878 for (i = 0; old_names[i]; i++) {
879 (void) zap_remove(dp->dp_meta_objset,
880 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
883 if (scn->scn_phys.scn_queue_obj != 0) {
884 VERIFY0(dmu_object_free(dp->dp_meta_objset,
885 scn->scn_phys.scn_queue_obj, tx));
886 scn->scn_phys.scn_queue_obj = 0;
888 scan_ds_queue_clear(scn);
889 scan_ds_prefetch_queue_clear(scn);
891 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
894 * If we were "restarted" from a stopped state, don't bother
895 * with anything else.
897 if (!dsl_scan_is_running(scn)) {
898 ASSERT(!scn->scn_is_sorted);
902 if (scn->scn_is_sorted) {
903 scan_io_queues_destroy(scn);
904 scn->scn_is_sorted = B_FALSE;
906 if (scn->scn_taskq != NULL) {
907 taskq_destroy(scn->scn_taskq);
908 scn->scn_taskq = NULL;
912 scn->scn_phys.scn_state = complete ? DSS_FINISHED : DSS_CANCELED;
914 spa_notify_waiters(spa);
916 if (dsl_scan_restarting(scn, tx))
917 spa_history_log_internal(spa, "scan aborted, restarting", tx,
918 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa));
920 spa_history_log_internal(spa, "scan cancelled", tx,
921 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa));
923 spa_history_log_internal(spa, "scan done", tx,
924 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa));
926 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
927 spa->spa_scrub_active = B_FALSE;
930 * If the scrub/resilver completed, update all DTLs to
931 * reflect this. Whether it succeeded or not, vacate
932 * all temporary scrub DTLs.
934 * As the scrub does not currently support traversing
935 * data that have been freed but are part of a checkpoint,
936 * we don't mark the scrub as done in the DTLs as faults
937 * may still exist in those vdevs.
940 !spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) {
941 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
942 scn->scn_phys.scn_max_txg, B_TRUE, B_FALSE);
944 if (scn->scn_phys.scn_min_txg) {
945 nvlist_t *aux = fnvlist_alloc();
946 fnvlist_add_string(aux, ZFS_EV_RESILVER_TYPE,
948 spa_event_notify(spa, NULL, aux,
949 ESC_ZFS_RESILVER_FINISH);
952 spa_event_notify(spa, NULL, NULL,
953 ESC_ZFS_SCRUB_FINISH);
956 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
959 spa_errlog_rotate(spa);
962 * Don't clear flag until after vdev_dtl_reassess to ensure that
963 * DTL_MISSING will get updated when possible.
965 spa->spa_scrub_started = B_FALSE;
968 * We may have finished replacing a device.
969 * Let the async thread assess this and handle the detach.
971 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
974 * Clear any resilver_deferred flags in the config.
975 * If there are drives that need resilvering, kick
976 * off an asynchronous request to start resilver.
977 * vdev_clear_resilver_deferred() may update the config
978 * before the resilver can restart. In the event of
979 * a crash during this period, the spa loading code
980 * will find the drives that need to be resilvered
981 * and start the resilver then.
983 if (spa_feature_is_enabled(spa, SPA_FEATURE_RESILVER_DEFER) &&
984 vdev_clear_resilver_deferred(spa->spa_root_vdev, tx)) {
985 spa_history_log_internal(spa,
986 "starting deferred resilver", tx, "errors=%llu",
987 (u_longlong_t)spa_get_errlog_size(spa));
988 spa_async_request(spa, SPA_ASYNC_RESILVER);
992 scn->scn_phys.scn_end_time = gethrestime_sec();
994 if (spa->spa_errata == ZPOOL_ERRATA_ZOL_2094_SCRUB)
997 ASSERT(!dsl_scan_is_running(scn));
1002 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
1004 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
1006 if (!dsl_scan_is_running(scn))
1007 return (SET_ERROR(ENOENT));
1013 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
1015 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
1017 dsl_scan_done(scn, B_FALSE, tx);
1018 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
1019 spa_event_notify(scn->scn_dp->dp_spa, NULL, NULL, ESC_ZFS_SCRUB_ABORT);
1023 dsl_scan_cancel(dsl_pool_t *dp)
1025 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
1026 dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED));
1030 dsl_scrub_pause_resume_check(void *arg, dmu_tx_t *tx)
1032 pool_scrub_cmd_t *cmd = arg;
1033 dsl_pool_t *dp = dmu_tx_pool(tx);
1034 dsl_scan_t *scn = dp->dp_scan;
1036 if (*cmd == POOL_SCRUB_PAUSE) {
1037 /* can't pause a scrub when there is no in-progress scrub */
1038 if (!dsl_scan_scrubbing(dp))
1039 return (SET_ERROR(ENOENT));
1041 /* can't pause a paused scrub */
1042 if (dsl_scan_is_paused_scrub(scn))
1043 return (SET_ERROR(EBUSY));
1044 } else if (*cmd != POOL_SCRUB_NORMAL) {
1045 return (SET_ERROR(ENOTSUP));
1052 dsl_scrub_pause_resume_sync(void *arg, dmu_tx_t *tx)
1054 pool_scrub_cmd_t *cmd = arg;
1055 dsl_pool_t *dp = dmu_tx_pool(tx);
1056 spa_t *spa = dp->dp_spa;
1057 dsl_scan_t *scn = dp->dp_scan;
1059 if (*cmd == POOL_SCRUB_PAUSE) {
1060 /* can't pause a scrub when there is no in-progress scrub */
1061 spa->spa_scan_pass_scrub_pause = gethrestime_sec();
1062 scn->scn_phys.scn_flags |= DSF_SCRUB_PAUSED;
1063 scn->scn_phys_cached.scn_flags |= DSF_SCRUB_PAUSED;
1064 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
1065 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_PAUSED);
1066 spa_notify_waiters(spa);
1068 ASSERT3U(*cmd, ==, POOL_SCRUB_NORMAL);
1069 if (dsl_scan_is_paused_scrub(scn)) {
1071 * We need to keep track of how much time we spend
1072 * paused per pass so that we can adjust the scrub rate
1073 * shown in the output of 'zpool status'
1075 spa->spa_scan_pass_scrub_spent_paused +=
1076 gethrestime_sec() - spa->spa_scan_pass_scrub_pause;
1077 spa->spa_scan_pass_scrub_pause = 0;
1078 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
1079 scn->scn_phys_cached.scn_flags &= ~DSF_SCRUB_PAUSED;
1080 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
1086 * Set scrub pause/resume state if it makes sense to do so
1089 dsl_scrub_set_pause_resume(const dsl_pool_t *dp, pool_scrub_cmd_t cmd)
1091 return (dsl_sync_task(spa_name(dp->dp_spa),
1092 dsl_scrub_pause_resume_check, dsl_scrub_pause_resume_sync, &cmd, 3,
1093 ZFS_SPACE_CHECK_RESERVED));
1097 /* start a new scan, or restart an existing one. */
1099 dsl_scan_restart_resilver(dsl_pool_t *dp, uint64_t txg)
1103 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1104 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1106 txg = dmu_tx_get_txg(tx);
1107 dp->dp_scan->scn_restart_txg = txg;
1110 dp->dp_scan->scn_restart_txg = txg;
1112 zfs_dbgmsg("restarting resilver txg=%llu", (longlong_t)txg);
1116 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
1118 zio_free(dp->dp_spa, txg, bp);
1122 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
1124 ASSERT(dsl_pool_sync_context(dp));
1125 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
1129 scan_ds_queue_compare(const void *a, const void *b)
1131 const scan_ds_t *sds_a = a, *sds_b = b;
1133 if (sds_a->sds_dsobj < sds_b->sds_dsobj)
1135 if (sds_a->sds_dsobj == sds_b->sds_dsobj)
1141 scan_ds_queue_clear(dsl_scan_t *scn)
1143 void *cookie = NULL;
1145 while ((sds = avl_destroy_nodes(&scn->scn_queue, &cookie)) != NULL) {
1146 kmem_free(sds, sizeof (*sds));
1151 scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj, uint64_t *txg)
1153 scan_ds_t srch, *sds;
1155 srch.sds_dsobj = dsobj;
1156 sds = avl_find(&scn->scn_queue, &srch, NULL);
1157 if (sds != NULL && txg != NULL)
1158 *txg = sds->sds_txg;
1159 return (sds != NULL);
1163 scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg)
1168 sds = kmem_zalloc(sizeof (*sds), KM_SLEEP);
1169 sds->sds_dsobj = dsobj;
1172 VERIFY3P(avl_find(&scn->scn_queue, sds, &where), ==, NULL);
1173 avl_insert(&scn->scn_queue, sds, where);
1177 scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj)
1179 scan_ds_t srch, *sds;
1181 srch.sds_dsobj = dsobj;
1183 sds = avl_find(&scn->scn_queue, &srch, NULL);
1184 VERIFY(sds != NULL);
1185 avl_remove(&scn->scn_queue, sds);
1186 kmem_free(sds, sizeof (*sds));
1190 scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx)
1192 dsl_pool_t *dp = scn->scn_dp;
1193 spa_t *spa = dp->dp_spa;
1194 dmu_object_type_t ot = (spa_version(spa) >= SPA_VERSION_DSL_SCRUB) ?
1195 DMU_OT_SCAN_QUEUE : DMU_OT_ZAP_OTHER;
1197 ASSERT0(scn->scn_bytes_pending);
1198 ASSERT(scn->scn_phys.scn_queue_obj != 0);
1200 VERIFY0(dmu_object_free(dp->dp_meta_objset,
1201 scn->scn_phys.scn_queue_obj, tx));
1202 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset, ot,
1203 DMU_OT_NONE, 0, tx);
1204 for (scan_ds_t *sds = avl_first(&scn->scn_queue);
1205 sds != NULL; sds = AVL_NEXT(&scn->scn_queue, sds)) {
1206 VERIFY0(zap_add_int_key(dp->dp_meta_objset,
1207 scn->scn_phys.scn_queue_obj, sds->sds_dsobj,
1213 * Computes the memory limit state that we're currently in. A sorted scan
1214 * needs quite a bit of memory to hold the sorting queue, so we need to
1215 * reasonably constrain the size so it doesn't impact overall system
1216 * performance. We compute two limits:
1217 * 1) Hard memory limit: if the amount of memory used by the sorting
1218 * queues on a pool gets above this value, we stop the metadata
1219 * scanning portion and start issuing the queued up and sorted
1220 * I/Os to reduce memory usage.
1221 * This limit is calculated as a fraction of physmem (by default 5%).
1222 * We constrain the lower bound of the hard limit to an absolute
1223 * minimum of zfs_scan_mem_lim_min (default: 16 MiB). We also constrain
1224 * the upper bound to 5% of the total pool size - no chance we'll
1225 * ever need that much memory, but just to keep the value in check.
1226 * 2) Soft memory limit: once we hit the hard memory limit, we start
1227 * issuing I/O to reduce queue memory usage, but we don't want to
1228 * completely empty out the queues, since we might be able to find I/Os
1229 * that will fill in the gaps of our non-sequential IOs at some point
1230 * in the future. So we stop the issuing of I/Os once the amount of
1231 * memory used drops below the soft limit (at which point we stop issuing
1232 * I/O and start scanning metadata again).
1234 * This limit is calculated by subtracting a fraction of the hard
1235 * limit from the hard limit. By default this fraction is 5%, so
1236 * the soft limit is 95% of the hard limit. We cap the size of the
1237 * difference between the hard and soft limits at an absolute
1238 * maximum of zfs_scan_mem_lim_soft_max (default: 128 MiB) - this is
1239 * sufficient to not cause too frequent switching between the
1240 * metadata scan and I/O issue (even at 2k recordsize, 128 MiB's
1241 * worth of queues is about 1.2 GiB of on-pool data, so scanning
1242 * that should take at least a decent fraction of a second).
1245 dsl_scan_should_clear(dsl_scan_t *scn)
1247 spa_t *spa = scn->scn_dp->dp_spa;
1248 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
1249 uint64_t alloc, mlim_hard, mlim_soft, mused;
1251 alloc = metaslab_class_get_alloc(spa_normal_class(spa));
1252 alloc += metaslab_class_get_alloc(spa_special_class(spa));
1253 alloc += metaslab_class_get_alloc(spa_dedup_class(spa));
1255 mlim_hard = MAX((physmem / zfs_scan_mem_lim_fact) * PAGESIZE,
1256 zfs_scan_mem_lim_min);
1257 mlim_hard = MIN(mlim_hard, alloc / 20);
1258 mlim_soft = mlim_hard - MIN(mlim_hard / zfs_scan_mem_lim_soft_fact,
1259 zfs_scan_mem_lim_soft_max);
1261 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
1262 vdev_t *tvd = rvd->vdev_child[i];
1263 dsl_scan_io_queue_t *queue;
1265 mutex_enter(&tvd->vdev_scan_io_queue_lock);
1266 queue = tvd->vdev_scan_io_queue;
1267 if (queue != NULL) {
1268 /* # extents in exts_by_size = # in exts_by_addr */
1269 mused += zfs_btree_numnodes(&queue->q_exts_by_size) *
1270 sizeof (range_seg_gap_t) + queue->q_sio_memused;
1272 mutex_exit(&tvd->vdev_scan_io_queue_lock);
1275 dprintf("current scan memory usage: %llu bytes\n", (longlong_t)mused);
1278 ASSERT0(scn->scn_bytes_pending);
1281 * If we are above our hard limit, we need to clear out memory.
1282 * If we are below our soft limit, we need to accumulate sequential IOs.
1283 * Otherwise, we should keep doing whatever we are currently doing.
1285 if (mused >= mlim_hard)
1287 else if (mused < mlim_soft)
1290 return (scn->scn_clearing);
1294 dsl_scan_check_suspend(dsl_scan_t *scn, const zbookmark_phys_t *zb)
1296 /* we never skip user/group accounting objects */
1297 if (zb && (int64_t)zb->zb_object < 0)
1300 if (scn->scn_suspending)
1301 return (B_TRUE); /* we're already suspending */
1303 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
1304 return (B_FALSE); /* we're resuming */
1306 /* We only know how to resume from level-0 and objset blocks. */
1307 if (zb && (zb->zb_level != 0 && zb->zb_level != ZB_ROOT_LEVEL))
1312 * - we have scanned for at least the minimum time (default 1 sec
1313 * for scrub, 3 sec for resilver), and either we have sufficient
1314 * dirty data that we are starting to write more quickly
1315 * (default 30%), someone is explicitly waiting for this txg
1316 * to complete, or we have used up all of the time in the txg
1317 * timeout (default 5 sec).
1319 * - the spa is shutting down because this pool is being exported
1320 * or the machine is rebooting.
1322 * - the scan queue has reached its memory use limit
1324 uint64_t curr_time_ns = gethrtime();
1325 uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time;
1326 uint64_t sync_time_ns = curr_time_ns -
1327 scn->scn_dp->dp_spa->spa_sync_starttime;
1328 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
1329 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
1330 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
1332 if ((NSEC2MSEC(scan_time_ns) > mintime &&
1333 (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent ||
1334 txg_sync_waiting(scn->scn_dp) ||
1335 NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) ||
1336 spa_shutting_down(scn->scn_dp->dp_spa) ||
1337 (zfs_scan_strict_mem_lim && dsl_scan_should_clear(scn))) {
1338 if (zb && zb->zb_level == ZB_ROOT_LEVEL) {
1339 dprintf("suspending at first available bookmark "
1340 "%llx/%llx/%llx/%llx\n",
1341 (longlong_t)zb->zb_objset,
1342 (longlong_t)zb->zb_object,
1343 (longlong_t)zb->zb_level,
1344 (longlong_t)zb->zb_blkid);
1345 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
1346 zb->zb_objset, 0, 0, 0);
1347 } else if (zb != NULL) {
1348 dprintf("suspending at bookmark %llx/%llx/%llx/%llx\n",
1349 (longlong_t)zb->zb_objset,
1350 (longlong_t)zb->zb_object,
1351 (longlong_t)zb->zb_level,
1352 (longlong_t)zb->zb_blkid);
1353 scn->scn_phys.scn_bookmark = *zb;
1356 dsl_scan_phys_t *scnp = &scn->scn_phys;
1357 dprintf("suspending at at DDT bookmark "
1358 "%llx/%llx/%llx/%llx\n",
1359 (longlong_t)scnp->scn_ddt_bookmark.ddb_class,
1360 (longlong_t)scnp->scn_ddt_bookmark.ddb_type,
1361 (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum,
1362 (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor);
1365 scn->scn_suspending = B_TRUE;
1371 typedef struct zil_scan_arg {
1373 zil_header_t *zsa_zh;
1378 dsl_scan_zil_block(zilog_t *zilog, const blkptr_t *bp, void *arg,
1381 zil_scan_arg_t *zsa = arg;
1382 dsl_pool_t *dp = zsa->zsa_dp;
1383 dsl_scan_t *scn = dp->dp_scan;
1384 zil_header_t *zh = zsa->zsa_zh;
1385 zbookmark_phys_t zb;
1387 ASSERT(!BP_IS_REDACTED(bp));
1388 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
1392 * One block ("stubby") can be allocated a long time ago; we
1393 * want to visit that one because it has been allocated
1394 * (on-disk) even if it hasn't been claimed (even though for
1395 * scrub there's nothing to do to it).
1397 if (claim_txg == 0 && bp->blk_birth >= spa_min_claim_txg(dp->dp_spa))
1400 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
1401 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
1403 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
1409 dsl_scan_zil_record(zilog_t *zilog, const lr_t *lrc, void *arg,
1412 if (lrc->lrc_txtype == TX_WRITE) {
1413 zil_scan_arg_t *zsa = arg;
1414 dsl_pool_t *dp = zsa->zsa_dp;
1415 dsl_scan_t *scn = dp->dp_scan;
1416 zil_header_t *zh = zsa->zsa_zh;
1417 const lr_write_t *lr = (const lr_write_t *)lrc;
1418 const blkptr_t *bp = &lr->lr_blkptr;
1419 zbookmark_phys_t zb;
1421 ASSERT(!BP_IS_REDACTED(bp));
1422 if (BP_IS_HOLE(bp) ||
1423 bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
1427 * birth can be < claim_txg if this record's txg is
1428 * already txg sync'ed (but this log block contains
1429 * other records that are not synced)
1431 if (claim_txg == 0 || bp->blk_birth < claim_txg)
1434 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
1435 lr->lr_foid, ZB_ZIL_LEVEL,
1436 lr->lr_offset / BP_GET_LSIZE(bp));
1438 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
1444 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
1446 uint64_t claim_txg = zh->zh_claim_txg;
1447 zil_scan_arg_t zsa = { dp, zh };
1450 ASSERT(spa_writeable(dp->dp_spa));
1453 * We only want to visit blocks that have been claimed but not yet
1454 * replayed (or, in read-only mode, blocks that *would* be claimed).
1459 zilog = zil_alloc(dp->dp_meta_objset, zh);
1461 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
1462 claim_txg, B_FALSE);
1468 * We compare scan_prefetch_issue_ctx_t's based on their bookmarks. The idea
1469 * here is to sort the AVL tree by the order each block will be needed.
1472 scan_prefetch_queue_compare(const void *a, const void *b)
1474 const scan_prefetch_issue_ctx_t *spic_a = a, *spic_b = b;
1475 const scan_prefetch_ctx_t *spc_a = spic_a->spic_spc;
1476 const scan_prefetch_ctx_t *spc_b = spic_b->spic_spc;
1478 return (zbookmark_compare(spc_a->spc_datablkszsec,
1479 spc_a->spc_indblkshift, spc_b->spc_datablkszsec,
1480 spc_b->spc_indblkshift, &spic_a->spic_zb, &spic_b->spic_zb));
1484 scan_prefetch_ctx_rele(scan_prefetch_ctx_t *spc, void *tag)
1486 if (zfs_refcount_remove(&spc->spc_refcnt, tag) == 0) {
1487 zfs_refcount_destroy(&spc->spc_refcnt);
1488 kmem_free(spc, sizeof (scan_prefetch_ctx_t));
1492 static scan_prefetch_ctx_t *
1493 scan_prefetch_ctx_create(dsl_scan_t *scn, dnode_phys_t *dnp, void *tag)
1495 scan_prefetch_ctx_t *spc;
1497 spc = kmem_alloc(sizeof (scan_prefetch_ctx_t), KM_SLEEP);
1498 zfs_refcount_create(&spc->spc_refcnt);
1499 zfs_refcount_add(&spc->spc_refcnt, tag);
1502 spc->spc_datablkszsec = dnp->dn_datablkszsec;
1503 spc->spc_indblkshift = dnp->dn_indblkshift;
1504 spc->spc_root = B_FALSE;
1506 spc->spc_datablkszsec = 0;
1507 spc->spc_indblkshift = 0;
1508 spc->spc_root = B_TRUE;
1515 scan_prefetch_ctx_add_ref(scan_prefetch_ctx_t *spc, void *tag)
1517 zfs_refcount_add(&spc->spc_refcnt, tag);
1521 scan_ds_prefetch_queue_clear(dsl_scan_t *scn)
1523 spa_t *spa = scn->scn_dp->dp_spa;
1524 void *cookie = NULL;
1525 scan_prefetch_issue_ctx_t *spic = NULL;
1527 mutex_enter(&spa->spa_scrub_lock);
1528 while ((spic = avl_destroy_nodes(&scn->scn_prefetch_queue,
1529 &cookie)) != NULL) {
1530 scan_prefetch_ctx_rele(spic->spic_spc, scn);
1531 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1533 mutex_exit(&spa->spa_scrub_lock);
1537 dsl_scan_check_prefetch_resume(scan_prefetch_ctx_t *spc,
1538 const zbookmark_phys_t *zb)
1540 zbookmark_phys_t *last_zb = &spc->spc_scn->scn_prefetch_bookmark;
1541 dnode_phys_t tmp_dnp;
1542 dnode_phys_t *dnp = (spc->spc_root) ? NULL : &tmp_dnp;
1544 if (zb->zb_objset != last_zb->zb_objset)
1546 if ((int64_t)zb->zb_object < 0)
1549 tmp_dnp.dn_datablkszsec = spc->spc_datablkszsec;
1550 tmp_dnp.dn_indblkshift = spc->spc_indblkshift;
1552 if (zbookmark_subtree_completed(dnp, zb, last_zb))
1559 dsl_scan_prefetch(scan_prefetch_ctx_t *spc, blkptr_t *bp, zbookmark_phys_t *zb)
1562 dsl_scan_t *scn = spc->spc_scn;
1563 spa_t *spa = scn->scn_dp->dp_spa;
1564 scan_prefetch_issue_ctx_t *spic;
1566 if (zfs_no_scrub_prefetch || BP_IS_REDACTED(bp))
1569 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg ||
1570 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE &&
1571 BP_GET_TYPE(bp) != DMU_OT_OBJSET))
1574 if (dsl_scan_check_prefetch_resume(spc, zb))
1577 scan_prefetch_ctx_add_ref(spc, scn);
1578 spic = kmem_alloc(sizeof (scan_prefetch_issue_ctx_t), KM_SLEEP);
1579 spic->spic_spc = spc;
1580 spic->spic_bp = *bp;
1581 spic->spic_zb = *zb;
1584 * Add the IO to the queue of blocks to prefetch. This allows us to
1585 * prioritize blocks that we will need first for the main traversal
1588 mutex_enter(&spa->spa_scrub_lock);
1589 if (avl_find(&scn->scn_prefetch_queue, spic, &idx) != NULL) {
1590 /* this block is already queued for prefetch */
1591 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1592 scan_prefetch_ctx_rele(spc, scn);
1593 mutex_exit(&spa->spa_scrub_lock);
1597 avl_insert(&scn->scn_prefetch_queue, spic, idx);
1598 cv_broadcast(&spa->spa_scrub_io_cv);
1599 mutex_exit(&spa->spa_scrub_lock);
1603 dsl_scan_prefetch_dnode(dsl_scan_t *scn, dnode_phys_t *dnp,
1604 uint64_t objset, uint64_t object)
1607 zbookmark_phys_t zb;
1608 scan_prefetch_ctx_t *spc;
1610 if (dnp->dn_nblkptr == 0 && !(dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1613 SET_BOOKMARK(&zb, objset, object, 0, 0);
1615 spc = scan_prefetch_ctx_create(scn, dnp, FTAG);
1617 for (i = 0; i < dnp->dn_nblkptr; i++) {
1618 zb.zb_level = BP_GET_LEVEL(&dnp->dn_blkptr[i]);
1620 dsl_scan_prefetch(spc, &dnp->dn_blkptr[i], &zb);
1623 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
1625 zb.zb_blkid = DMU_SPILL_BLKID;
1626 dsl_scan_prefetch(spc, DN_SPILL_BLKPTR(dnp), &zb);
1629 scan_prefetch_ctx_rele(spc, FTAG);
1633 dsl_scan_prefetch_cb(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp,
1634 arc_buf_t *buf, void *private)
1636 scan_prefetch_ctx_t *spc = private;
1637 dsl_scan_t *scn = spc->spc_scn;
1638 spa_t *spa = scn->scn_dp->dp_spa;
1640 /* broadcast that the IO has completed for rate limiting purposes */
1641 mutex_enter(&spa->spa_scrub_lock);
1642 ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp));
1643 spa->spa_scrub_inflight -= BP_GET_PSIZE(bp);
1644 cv_broadcast(&spa->spa_scrub_io_cv);
1645 mutex_exit(&spa->spa_scrub_lock);
1647 /* if there was an error or we are done prefetching, just cleanup */
1648 if (buf == NULL || scn->scn_prefetch_stop)
1651 if (BP_GET_LEVEL(bp) > 0) {
1654 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
1655 zbookmark_phys_t czb;
1657 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
1658 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
1659 zb->zb_level - 1, zb->zb_blkid * epb + i);
1660 dsl_scan_prefetch(spc, cbp, &czb);
1662 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
1665 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
1667 for (i = 0, cdnp = buf->b_data; i < epb;
1668 i += cdnp->dn_extra_slots + 1,
1669 cdnp += cdnp->dn_extra_slots + 1) {
1670 dsl_scan_prefetch_dnode(scn, cdnp,
1671 zb->zb_objset, zb->zb_blkid * epb + i);
1673 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
1674 objset_phys_t *osp = buf->b_data;
1676 dsl_scan_prefetch_dnode(scn, &osp->os_meta_dnode,
1677 zb->zb_objset, DMU_META_DNODE_OBJECT);
1679 if (OBJSET_BUF_HAS_USERUSED(buf)) {
1680 dsl_scan_prefetch_dnode(scn,
1681 &osp->os_groupused_dnode, zb->zb_objset,
1682 DMU_GROUPUSED_OBJECT);
1683 dsl_scan_prefetch_dnode(scn,
1684 &osp->os_userused_dnode, zb->zb_objset,
1685 DMU_USERUSED_OBJECT);
1691 arc_buf_destroy(buf, private);
1692 scan_prefetch_ctx_rele(spc, scn);
1697 dsl_scan_prefetch_thread(void *arg)
1699 dsl_scan_t *scn = arg;
1700 spa_t *spa = scn->scn_dp->dp_spa;
1701 scan_prefetch_issue_ctx_t *spic;
1703 /* loop until we are told to stop */
1704 while (!scn->scn_prefetch_stop) {
1705 arc_flags_t flags = ARC_FLAG_NOWAIT |
1706 ARC_FLAG_PRESCIENT_PREFETCH | ARC_FLAG_PREFETCH;
1707 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
1709 mutex_enter(&spa->spa_scrub_lock);
1712 * Wait until we have an IO to issue and are not above our
1713 * maximum in flight limit.
1715 while (!scn->scn_prefetch_stop &&
1716 (avl_numnodes(&scn->scn_prefetch_queue) == 0 ||
1717 spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes)) {
1718 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1721 /* recheck if we should stop since we waited for the cv */
1722 if (scn->scn_prefetch_stop) {
1723 mutex_exit(&spa->spa_scrub_lock);
1727 /* remove the prefetch IO from the tree */
1728 spic = avl_first(&scn->scn_prefetch_queue);
1729 spa->spa_scrub_inflight += BP_GET_PSIZE(&spic->spic_bp);
1730 avl_remove(&scn->scn_prefetch_queue, spic);
1732 mutex_exit(&spa->spa_scrub_lock);
1734 if (BP_IS_PROTECTED(&spic->spic_bp)) {
1735 ASSERT(BP_GET_TYPE(&spic->spic_bp) == DMU_OT_DNODE ||
1736 BP_GET_TYPE(&spic->spic_bp) == DMU_OT_OBJSET);
1737 ASSERT3U(BP_GET_LEVEL(&spic->spic_bp), ==, 0);
1738 zio_flags |= ZIO_FLAG_RAW;
1741 /* issue the prefetch asynchronously */
1742 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa,
1743 &spic->spic_bp, dsl_scan_prefetch_cb, spic->spic_spc,
1744 ZIO_PRIORITY_SCRUB, zio_flags, &flags, &spic->spic_zb);
1746 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1749 ASSERT(scn->scn_prefetch_stop);
1751 /* free any prefetches we didn't get to complete */
1752 mutex_enter(&spa->spa_scrub_lock);
1753 while ((spic = avl_first(&scn->scn_prefetch_queue)) != NULL) {
1754 avl_remove(&scn->scn_prefetch_queue, spic);
1755 scan_prefetch_ctx_rele(spic->spic_spc, scn);
1756 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1758 ASSERT0(avl_numnodes(&scn->scn_prefetch_queue));
1759 mutex_exit(&spa->spa_scrub_lock);
1763 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
1764 const zbookmark_phys_t *zb)
1767 * We never skip over user/group accounting objects (obj<0)
1769 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
1770 (int64_t)zb->zb_object >= 0) {
1772 * If we already visited this bp & everything below (in
1773 * a prior txg sync), don't bother doing it again.
1775 if (zbookmark_subtree_completed(dnp, zb,
1776 &scn->scn_phys.scn_bookmark))
1780 * If we found the block we're trying to resume from, or
1781 * we went past it to a different object, zero it out to
1782 * indicate that it's OK to start checking for suspending
1785 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
1786 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
1787 dprintf("resuming at %llx/%llx/%llx/%llx\n",
1788 (longlong_t)zb->zb_objset,
1789 (longlong_t)zb->zb_object,
1790 (longlong_t)zb->zb_level,
1791 (longlong_t)zb->zb_blkid);
1792 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
1798 static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
1799 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
1800 dmu_objset_type_t ostype, dmu_tx_t *tx);
1801 inline __attribute__((always_inline)) static void dsl_scan_visitdnode(
1802 dsl_scan_t *, dsl_dataset_t *ds, dmu_objset_type_t ostype,
1803 dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
1806 * Return nonzero on i/o error.
1807 * Return new buf to write out in *bufp.
1809 inline __attribute__((always_inline)) static int
1810 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
1811 dnode_phys_t *dnp, const blkptr_t *bp,
1812 const zbookmark_phys_t *zb, dmu_tx_t *tx)
1814 dsl_pool_t *dp = scn->scn_dp;
1815 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
1818 ASSERT(!BP_IS_REDACTED(bp));
1820 if (BP_GET_LEVEL(bp) > 0) {
1821 arc_flags_t flags = ARC_FLAG_WAIT;
1824 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
1827 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1828 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb);
1830 scn->scn_phys.scn_errors++;
1833 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
1834 zbookmark_phys_t czb;
1836 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
1838 zb->zb_blkid * epb + i);
1839 dsl_scan_visitbp(cbp, &czb, dnp,
1840 ds, scn, ostype, tx);
1842 arc_buf_destroy(buf, &buf);
1843 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
1844 arc_flags_t flags = ARC_FLAG_WAIT;
1847 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
1850 if (BP_IS_PROTECTED(bp)) {
1851 ASSERT3U(BP_GET_COMPRESS(bp), ==, ZIO_COMPRESS_OFF);
1852 zio_flags |= ZIO_FLAG_RAW;
1855 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1856 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb);
1858 scn->scn_phys.scn_errors++;
1861 for (i = 0, cdnp = buf->b_data; i < epb;
1862 i += cdnp->dn_extra_slots + 1,
1863 cdnp += cdnp->dn_extra_slots + 1) {
1864 dsl_scan_visitdnode(scn, ds, ostype,
1865 cdnp, zb->zb_blkid * epb + i, tx);
1868 arc_buf_destroy(buf, &buf);
1869 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
1870 arc_flags_t flags = ARC_FLAG_WAIT;
1874 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1875 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb);
1877 scn->scn_phys.scn_errors++;
1883 dsl_scan_visitdnode(scn, ds, osp->os_type,
1884 &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx);
1886 if (OBJSET_BUF_HAS_USERUSED(buf)) {
1888 * We also always visit user/group/project accounting
1889 * objects, and never skip them, even if we are
1890 * suspending. This is necessary so that the
1891 * space deltas from this txg get integrated.
1893 if (OBJSET_BUF_HAS_PROJECTUSED(buf))
1894 dsl_scan_visitdnode(scn, ds, osp->os_type,
1895 &osp->os_projectused_dnode,
1896 DMU_PROJECTUSED_OBJECT, tx);
1897 dsl_scan_visitdnode(scn, ds, osp->os_type,
1898 &osp->os_groupused_dnode,
1899 DMU_GROUPUSED_OBJECT, tx);
1900 dsl_scan_visitdnode(scn, ds, osp->os_type,
1901 &osp->os_userused_dnode,
1902 DMU_USERUSED_OBJECT, tx);
1904 arc_buf_destroy(buf, &buf);
1910 inline __attribute__((always_inline)) static void
1911 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
1912 dmu_objset_type_t ostype, dnode_phys_t *dnp,
1913 uint64_t object, dmu_tx_t *tx)
1917 for (j = 0; j < dnp->dn_nblkptr; j++) {
1918 zbookmark_phys_t czb;
1920 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
1921 dnp->dn_nlevels - 1, j);
1922 dsl_scan_visitbp(&dnp->dn_blkptr[j],
1923 &czb, dnp, ds, scn, ostype, tx);
1926 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
1927 zbookmark_phys_t czb;
1928 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
1929 0, DMU_SPILL_BLKID);
1930 dsl_scan_visitbp(DN_SPILL_BLKPTR(dnp),
1931 &czb, dnp, ds, scn, ostype, tx);
1936 * The arguments are in this order because mdb can only print the
1937 * first 5; we want them to be useful.
1940 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
1941 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
1942 dmu_objset_type_t ostype, dmu_tx_t *tx)
1944 dsl_pool_t *dp = scn->scn_dp;
1945 blkptr_t *bp_toread = NULL;
1947 if (dsl_scan_check_suspend(scn, zb))
1950 if (dsl_scan_check_resume(scn, dnp, zb))
1953 scn->scn_visited_this_txg++;
1956 * This debugging is commented out to conserve stack space. This
1957 * function is called recursively and the debugging adds several
1958 * bytes to the stack for each call. It can be commented back in
1959 * if required to debug an issue in dsl_scan_visitbp().
1962 * "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
1963 * ds, ds ? ds->ds_object : 0,
1964 * zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
1968 if (BP_IS_HOLE(bp)) {
1969 scn->scn_holes_this_txg++;
1973 if (BP_IS_REDACTED(bp)) {
1974 ASSERT(dsl_dataset_feature_is_active(ds,
1975 SPA_FEATURE_REDACTED_DATASETS));
1979 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg) {
1980 scn->scn_lt_min_this_txg++;
1984 bp_toread = kmem_alloc(sizeof (blkptr_t), KM_SLEEP);
1987 if (dsl_scan_recurse(scn, ds, ostype, dnp, bp_toread, zb, tx) != 0)
1991 * If dsl_scan_ddt() has already visited this block, it will have
1992 * already done any translations or scrubbing, so don't call the
1995 if (ddt_class_contains(dp->dp_spa,
1996 scn->scn_phys.scn_ddt_class_max, bp)) {
1997 scn->scn_ddt_contained_this_txg++;
2002 * If this block is from the future (after cur_max_txg), then we
2003 * are doing this on behalf of a deleted snapshot, and we will
2004 * revisit the future block on the next pass of this dataset.
2005 * Don't scan it now unless we need to because something
2006 * under it was modified.
2008 if (BP_PHYSICAL_BIRTH(bp) > scn->scn_phys.scn_cur_max_txg) {
2009 scn->scn_gt_max_this_txg++;
2013 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
2016 kmem_free(bp_toread, sizeof (blkptr_t));
2020 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
2023 zbookmark_phys_t zb;
2024 scan_prefetch_ctx_t *spc;
2026 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
2027 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
2029 if (ZB_IS_ZERO(&scn->scn_phys.scn_bookmark)) {
2030 SET_BOOKMARK(&scn->scn_prefetch_bookmark,
2031 zb.zb_objset, 0, 0, 0);
2033 scn->scn_prefetch_bookmark = scn->scn_phys.scn_bookmark;
2036 scn->scn_objsets_visited_this_txg++;
2038 spc = scan_prefetch_ctx_create(scn, NULL, FTAG);
2039 dsl_scan_prefetch(spc, bp, &zb);
2040 scan_prefetch_ctx_rele(spc, FTAG);
2042 dsl_scan_visitbp(bp, &zb, NULL, ds, scn, DMU_OST_NONE, tx);
2044 dprintf_ds(ds, "finished scan%s", "");
2048 ds_destroyed_scn_phys(dsl_dataset_t *ds, dsl_scan_phys_t *scn_phys)
2050 if (scn_phys->scn_bookmark.zb_objset == ds->ds_object) {
2051 if (ds->ds_is_snapshot) {
2054 * - scn_cur_{min,max}_txg stays the same.
2055 * - Setting the flag is not really necessary if
2056 * scn_cur_max_txg == scn_max_txg, because there
2057 * is nothing after this snapshot that we care
2058 * about. However, we set it anyway and then
2059 * ignore it when we retraverse it in
2060 * dsl_scan_visitds().
2062 scn_phys->scn_bookmark.zb_objset =
2063 dsl_dataset_phys(ds)->ds_next_snap_obj;
2064 zfs_dbgmsg("destroying ds %llu; currently traversing; "
2065 "reset zb_objset to %llu",
2066 (u_longlong_t)ds->ds_object,
2067 (u_longlong_t)dsl_dataset_phys(ds)->
2069 scn_phys->scn_flags |= DSF_VISIT_DS_AGAIN;
2071 SET_BOOKMARK(&scn_phys->scn_bookmark,
2072 ZB_DESTROYED_OBJSET, 0, 0, 0);
2073 zfs_dbgmsg("destroying ds %llu; currently traversing; "
2074 "reset bookmark to -1,0,0,0",
2075 (u_longlong_t)ds->ds_object);
2081 * Invoked when a dataset is destroyed. We need to make sure that:
2083 * 1) If it is the dataset that was currently being scanned, we write
2084 * a new dsl_scan_phys_t and marking the objset reference in it
2086 * 2) Remove it from the work queue, if it was present.
2088 * If the dataset was actually a snapshot, instead of marking the dataset
2089 * as destroyed, we instead substitute the next snapshot in line.
2092 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
2094 dsl_pool_t *dp = ds->ds_dir->dd_pool;
2095 dsl_scan_t *scn = dp->dp_scan;
2098 if (!dsl_scan_is_running(scn))
2101 ds_destroyed_scn_phys(ds, &scn->scn_phys);
2102 ds_destroyed_scn_phys(ds, &scn->scn_phys_cached);
2104 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
2105 scan_ds_queue_remove(scn, ds->ds_object);
2106 if (ds->ds_is_snapshot)
2107 scan_ds_queue_insert(scn,
2108 dsl_dataset_phys(ds)->ds_next_snap_obj, mintxg);
2111 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
2112 ds->ds_object, &mintxg) == 0) {
2113 ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
2114 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
2115 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
2116 if (ds->ds_is_snapshot) {
2118 * We keep the same mintxg; it could be >
2119 * ds_creation_txg if the previous snapshot was
2122 VERIFY(zap_add_int_key(dp->dp_meta_objset,
2123 scn->scn_phys.scn_queue_obj,
2124 dsl_dataset_phys(ds)->ds_next_snap_obj,
2126 zfs_dbgmsg("destroying ds %llu; in queue; "
2127 "replacing with %llu",
2128 (u_longlong_t)ds->ds_object,
2129 (u_longlong_t)dsl_dataset_phys(ds)->
2132 zfs_dbgmsg("destroying ds %llu; in queue; removing",
2133 (u_longlong_t)ds->ds_object);
2138 * dsl_scan_sync() should be called after this, and should sync
2139 * out our changed state, but just to be safe, do it here.
2141 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
2145 ds_snapshotted_bookmark(dsl_dataset_t *ds, zbookmark_phys_t *scn_bookmark)
2147 if (scn_bookmark->zb_objset == ds->ds_object) {
2148 scn_bookmark->zb_objset =
2149 dsl_dataset_phys(ds)->ds_prev_snap_obj;
2150 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
2151 "reset zb_objset to %llu",
2152 (u_longlong_t)ds->ds_object,
2153 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
2158 * Called when a dataset is snapshotted. If we were currently traversing
2159 * this snapshot, we reset our bookmark to point at the newly created
2160 * snapshot. We also modify our work queue to remove the old snapshot and
2161 * replace with the new one.
2164 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
2166 dsl_pool_t *dp = ds->ds_dir->dd_pool;
2167 dsl_scan_t *scn = dp->dp_scan;
2170 if (!dsl_scan_is_running(scn))
2173 ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
2175 ds_snapshotted_bookmark(ds, &scn->scn_phys.scn_bookmark);
2176 ds_snapshotted_bookmark(ds, &scn->scn_phys_cached.scn_bookmark);
2178 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
2179 scan_ds_queue_remove(scn, ds->ds_object);
2180 scan_ds_queue_insert(scn,
2181 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg);
2184 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
2185 ds->ds_object, &mintxg) == 0) {
2186 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
2187 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
2188 VERIFY(zap_add_int_key(dp->dp_meta_objset,
2189 scn->scn_phys.scn_queue_obj,
2190 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg, tx) == 0);
2191 zfs_dbgmsg("snapshotting ds %llu; in queue; "
2192 "replacing with %llu",
2193 (u_longlong_t)ds->ds_object,
2194 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
2197 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
2201 ds_clone_swapped_bookmark(dsl_dataset_t *ds1, dsl_dataset_t *ds2,
2202 zbookmark_phys_t *scn_bookmark)
2204 if (scn_bookmark->zb_objset == ds1->ds_object) {
2205 scn_bookmark->zb_objset = ds2->ds_object;
2206 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
2207 "reset zb_objset to %llu",
2208 (u_longlong_t)ds1->ds_object,
2209 (u_longlong_t)ds2->ds_object);
2210 } else if (scn_bookmark->zb_objset == ds2->ds_object) {
2211 scn_bookmark->zb_objset = ds1->ds_object;
2212 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
2213 "reset zb_objset to %llu",
2214 (u_longlong_t)ds2->ds_object,
2215 (u_longlong_t)ds1->ds_object);
2220 * Called when an origin dataset and its clone are swapped. If we were
2221 * currently traversing the dataset, we need to switch to traversing the
2222 * newly promoted clone.
2225 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
2227 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
2228 dsl_scan_t *scn = dp->dp_scan;
2229 uint64_t mintxg1, mintxg2;
2230 boolean_t ds1_queued, ds2_queued;
2232 if (!dsl_scan_is_running(scn))
2235 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys.scn_bookmark);
2236 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys_cached.scn_bookmark);
2239 * Handle the in-memory scan queue.
2241 ds1_queued = scan_ds_queue_contains(scn, ds1->ds_object, &mintxg1);
2242 ds2_queued = scan_ds_queue_contains(scn, ds2->ds_object, &mintxg2);
2244 /* Sanity checking. */
2246 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2247 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2250 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2251 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2254 if (ds1_queued && ds2_queued) {
2256 * If both are queued, we don't need to do anything.
2257 * The swapping code below would not handle this case correctly,
2258 * since we can't insert ds2 if it is already there. That's
2259 * because scan_ds_queue_insert() prohibits a duplicate insert
2262 } else if (ds1_queued) {
2263 scan_ds_queue_remove(scn, ds1->ds_object);
2264 scan_ds_queue_insert(scn, ds2->ds_object, mintxg1);
2265 } else if (ds2_queued) {
2266 scan_ds_queue_remove(scn, ds2->ds_object);
2267 scan_ds_queue_insert(scn, ds1->ds_object, mintxg2);
2271 * Handle the on-disk scan queue.
2272 * The on-disk state is an out-of-date version of the in-memory state,
2273 * so the in-memory and on-disk values for ds1_queued and ds2_queued may
2274 * be different. Therefore we need to apply the swap logic to the
2275 * on-disk state independently of the in-memory state.
2277 ds1_queued = zap_lookup_int_key(dp->dp_meta_objset,
2278 scn->scn_phys.scn_queue_obj, ds1->ds_object, &mintxg1) == 0;
2279 ds2_queued = zap_lookup_int_key(dp->dp_meta_objset,
2280 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg2) == 0;
2282 /* Sanity checking. */
2284 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2285 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2288 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2289 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2292 if (ds1_queued && ds2_queued) {
2294 * If both are queued, we don't need to do anything.
2295 * Alternatively, we could check for EEXIST from
2296 * zap_add_int_key() and back out to the original state, but
2297 * that would be more work than checking for this case upfront.
2299 } else if (ds1_queued) {
2300 VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset,
2301 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
2302 VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset,
2303 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg1, tx));
2304 zfs_dbgmsg("clone_swap ds %llu; in queue; "
2305 "replacing with %llu",
2306 (u_longlong_t)ds1->ds_object,
2307 (u_longlong_t)ds2->ds_object);
2308 } else if (ds2_queued) {
2309 VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset,
2310 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
2311 VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset,
2312 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg2, tx));
2313 zfs_dbgmsg("clone_swap ds %llu; in queue; "
2314 "replacing with %llu",
2315 (u_longlong_t)ds2->ds_object,
2316 (u_longlong_t)ds1->ds_object);
2319 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
2324 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
2326 uint64_t originobj = *(uint64_t *)arg;
2329 dsl_scan_t *scn = dp->dp_scan;
2331 if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != originobj)
2334 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
2338 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != originobj) {
2339 dsl_dataset_t *prev;
2340 err = dsl_dataset_hold_obj(dp,
2341 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
2343 dsl_dataset_rele(ds, FTAG);
2348 scan_ds_queue_insert(scn, ds->ds_object,
2349 dsl_dataset_phys(ds)->ds_prev_snap_txg);
2350 dsl_dataset_rele(ds, FTAG);
2355 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
2357 dsl_pool_t *dp = scn->scn_dp;
2360 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
2362 if (scn->scn_phys.scn_cur_min_txg >=
2363 scn->scn_phys.scn_max_txg) {
2365 * This can happen if this snapshot was created after the
2366 * scan started, and we already completed a previous snapshot
2367 * that was created after the scan started. This snapshot
2368 * only references blocks with:
2370 * birth < our ds_creation_txg
2371 * cur_min_txg is no less than ds_creation_txg.
2372 * We have already visited these blocks.
2374 * birth > scn_max_txg
2375 * The scan requested not to visit these blocks.
2377 * Subsequent snapshots (and clones) can reference our
2378 * blocks, or blocks with even higher birth times.
2379 * Therefore we do not need to visit them either,
2380 * so we do not add them to the work queue.
2382 * Note that checking for cur_min_txg >= cur_max_txg
2383 * is not sufficient, because in that case we may need to
2384 * visit subsequent snapshots. This happens when min_txg > 0,
2385 * which raises cur_min_txg. In this case we will visit
2386 * this dataset but skip all of its blocks, because the
2387 * rootbp's birth time is < cur_min_txg. Then we will
2388 * add the next snapshots/clones to the work queue.
2390 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
2391 dsl_dataset_name(ds, dsname);
2392 zfs_dbgmsg("scanning dataset %llu (%s) is unnecessary because "
2393 "cur_min_txg (%llu) >= max_txg (%llu)",
2394 (longlong_t)dsobj, dsname,
2395 (longlong_t)scn->scn_phys.scn_cur_min_txg,
2396 (longlong_t)scn->scn_phys.scn_max_txg);
2397 kmem_free(dsname, MAXNAMELEN);
2403 * Only the ZIL in the head (non-snapshot) is valid. Even though
2404 * snapshots can have ZIL block pointers (which may be the same
2405 * BP as in the head), they must be ignored. In addition, $ORIGIN
2406 * doesn't have a objset (i.e. its ds_bp is a hole) so we don't
2407 * need to look for a ZIL in it either. So we traverse the ZIL here,
2408 * rather than in scan_recurse(), because the regular snapshot
2409 * block-sharing rules don't apply to it.
2411 if (!dsl_dataset_is_snapshot(ds) &&
2412 (dp->dp_origin_snap == NULL ||
2413 ds->ds_dir != dp->dp_origin_snap->ds_dir)) {
2415 if (dmu_objset_from_ds(ds, &os) != 0) {
2418 dsl_scan_zil(dp, &os->os_zil_header);
2422 * Iterate over the bps in this ds.
2424 dmu_buf_will_dirty(ds->ds_dbuf, tx);
2425 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
2426 dsl_scan_visit_rootbp(scn, ds, &dsl_dataset_phys(ds)->ds_bp, tx);
2427 rrw_exit(&ds->ds_bp_rwlock, FTAG);
2429 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
2430 dsl_dataset_name(ds, dsname);
2431 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
2433 (longlong_t)dsobj, dsname,
2434 (longlong_t)scn->scn_phys.scn_cur_min_txg,
2435 (longlong_t)scn->scn_phys.scn_cur_max_txg,
2436 (int)scn->scn_suspending);
2437 kmem_free(dsname, ZFS_MAX_DATASET_NAME_LEN);
2439 if (scn->scn_suspending)
2443 * We've finished this pass over this dataset.
2447 * If we did not completely visit this dataset, do another pass.
2449 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
2450 zfs_dbgmsg("incomplete pass; visiting again");
2451 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
2452 scan_ds_queue_insert(scn, ds->ds_object,
2453 scn->scn_phys.scn_cur_max_txg);
2458 * Add descendant datasets to work queue.
2460 if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
2461 scan_ds_queue_insert(scn,
2462 dsl_dataset_phys(ds)->ds_next_snap_obj,
2463 dsl_dataset_phys(ds)->ds_creation_txg);
2465 if (dsl_dataset_phys(ds)->ds_num_children > 1) {
2466 boolean_t usenext = B_FALSE;
2467 if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
2470 * A bug in a previous version of the code could
2471 * cause upgrade_clones_cb() to not set
2472 * ds_next_snap_obj when it should, leading to a
2473 * missing entry. Therefore we can only use the
2474 * next_clones_obj when its count is correct.
2476 int err = zap_count(dp->dp_meta_objset,
2477 dsl_dataset_phys(ds)->ds_next_clones_obj, &count);
2479 count == dsl_dataset_phys(ds)->ds_num_children - 1)
2486 for (zap_cursor_init(&zc, dp->dp_meta_objset,
2487 dsl_dataset_phys(ds)->ds_next_clones_obj);
2488 zap_cursor_retrieve(&zc, &za) == 0;
2489 (void) zap_cursor_advance(&zc)) {
2490 scan_ds_queue_insert(scn,
2491 zfs_strtonum(za.za_name, NULL),
2492 dsl_dataset_phys(ds)->ds_creation_txg);
2494 zap_cursor_fini(&zc);
2496 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
2497 enqueue_clones_cb, &ds->ds_object,
2503 dsl_dataset_rele(ds, FTAG);
2508 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
2512 dsl_scan_t *scn = dp->dp_scan;
2514 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
2518 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
2519 dsl_dataset_t *prev;
2520 err = dsl_dataset_hold_obj(dp,
2521 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
2523 dsl_dataset_rele(ds, FTAG);
2528 * If this is a clone, we don't need to worry about it for now.
2530 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) {
2531 dsl_dataset_rele(ds, FTAG);
2532 dsl_dataset_rele(prev, FTAG);
2535 dsl_dataset_rele(ds, FTAG);
2539 scan_ds_queue_insert(scn, ds->ds_object,
2540 dsl_dataset_phys(ds)->ds_prev_snap_txg);
2541 dsl_dataset_rele(ds, FTAG);
2547 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
2548 ddt_entry_t *dde, dmu_tx_t *tx)
2550 const ddt_key_t *ddk = &dde->dde_key;
2551 ddt_phys_t *ddp = dde->dde_phys;
2553 zbookmark_phys_t zb = { 0 };
2556 if (!dsl_scan_is_running(scn))
2560 * This function is special because it is the only thing
2561 * that can add scan_io_t's to the vdev scan queues from
2562 * outside dsl_scan_sync(). For the most part this is ok
2563 * as long as it is called from within syncing context.
2564 * However, dsl_scan_sync() expects that no new sio's will
2565 * be added between when all the work for a scan is done
2566 * and the next txg when the scan is actually marked as
2567 * completed. This check ensures we do not issue new sio's
2568 * during this period.
2570 if (scn->scn_done_txg != 0)
2573 for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
2574 if (ddp->ddp_phys_birth == 0 ||
2575 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
2577 ddt_bp_create(checksum, ddk, ddp, &bp);
2579 scn->scn_visited_this_txg++;
2580 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
2585 * Scrub/dedup interaction.
2587 * If there are N references to a deduped block, we don't want to scrub it
2588 * N times -- ideally, we should scrub it exactly once.
2590 * We leverage the fact that the dde's replication class (enum ddt_class)
2591 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
2592 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
2594 * To prevent excess scrubbing, the scrub begins by walking the DDT
2595 * to find all blocks with refcnt > 1, and scrubs each of these once.
2596 * Since there are two replication classes which contain blocks with
2597 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
2598 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
2600 * There would be nothing more to say if a block's refcnt couldn't change
2601 * during a scrub, but of course it can so we must account for changes
2602 * in a block's replication class.
2604 * Here's an example of what can occur:
2606 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
2607 * when visited during the top-down scrub phase, it will be scrubbed twice.
2608 * This negates our scrub optimization, but is otherwise harmless.
2610 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
2611 * on each visit during the top-down scrub phase, it will never be scrubbed.
2612 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
2613 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
2614 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
2615 * while a scrub is in progress, it scrubs the block right then.
2618 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
2620 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
2625 bzero(&dde, sizeof (ddt_entry_t));
2627 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
2630 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
2632 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
2633 (longlong_t)ddb->ddb_class,
2634 (longlong_t)ddb->ddb_type,
2635 (longlong_t)ddb->ddb_checksum,
2636 (longlong_t)ddb->ddb_cursor);
2638 /* There should be no pending changes to the dedup table */
2639 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
2640 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
2642 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
2645 if (dsl_scan_check_suspend(scn, NULL))
2649 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; "
2650 "suspending=%u", (longlong_t)n,
2651 (int)scn->scn_phys.scn_ddt_class_max, (int)scn->scn_suspending);
2653 ASSERT(error == 0 || error == ENOENT);
2654 ASSERT(error != ENOENT ||
2655 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
2659 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
2661 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
2662 if (ds->ds_is_snapshot)
2663 return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
2668 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
2671 dsl_pool_t *dp = scn->scn_dp;
2673 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
2674 scn->scn_phys.scn_ddt_class_max) {
2675 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
2676 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
2677 dsl_scan_ddt(scn, tx);
2678 if (scn->scn_suspending)
2682 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
2683 /* First do the MOS & ORIGIN */
2685 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
2686 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
2687 dsl_scan_visit_rootbp(scn, NULL,
2688 &dp->dp_meta_rootbp, tx);
2689 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
2690 if (scn->scn_suspending)
2693 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
2694 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
2695 enqueue_cb, NULL, DS_FIND_CHILDREN));
2697 dsl_scan_visitds(scn,
2698 dp->dp_origin_snap->ds_object, tx);
2700 ASSERT(!scn->scn_suspending);
2701 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
2702 ZB_DESTROYED_OBJSET) {
2703 uint64_t dsobj = scn->scn_phys.scn_bookmark.zb_objset;
2705 * If we were suspended, continue from here. Note if the
2706 * ds we were suspended on was deleted, the zb_objset may
2707 * be -1, so we will skip this and find a new objset
2710 dsl_scan_visitds(scn, dsobj, tx);
2711 if (scn->scn_suspending)
2716 * In case we suspended right at the end of the ds, zero the
2717 * bookmark so we don't think that we're still trying to resume.
2719 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_phys_t));
2722 * Keep pulling things out of the dataset avl queue. Updates to the
2723 * persistent zap-object-as-queue happen only at checkpoints.
2725 while ((sds = avl_first(&scn->scn_queue)) != NULL) {
2727 uint64_t dsobj = sds->sds_dsobj;
2728 uint64_t txg = sds->sds_txg;
2730 /* dequeue and free the ds from the queue */
2731 scan_ds_queue_remove(scn, dsobj);
2734 /* set up min / max txg */
2735 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
2737 scn->scn_phys.scn_cur_min_txg =
2738 MAX(scn->scn_phys.scn_min_txg, txg);
2740 scn->scn_phys.scn_cur_min_txg =
2741 MAX(scn->scn_phys.scn_min_txg,
2742 dsl_dataset_phys(ds)->ds_prev_snap_txg);
2744 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
2745 dsl_dataset_rele(ds, FTAG);
2747 dsl_scan_visitds(scn, dsobj, tx);
2748 if (scn->scn_suspending)
2752 /* No more objsets to fetch, we're done */
2753 scn->scn_phys.scn_bookmark.zb_objset = ZB_DESTROYED_OBJSET;
2754 ASSERT0(scn->scn_suspending);
2758 dsl_scan_count_leaves(vdev_t *vd)
2760 uint64_t i, leaves = 0;
2762 /* we only count leaves that belong to the main pool and are readable */
2763 if (vd->vdev_islog || vd->vdev_isspare ||
2764 vd->vdev_isl2cache || !vdev_readable(vd))
2767 if (vd->vdev_ops->vdev_op_leaf)
2770 for (i = 0; i < vd->vdev_children; i++) {
2771 leaves += dsl_scan_count_leaves(vd->vdev_child[i]);
2778 scan_io_queues_update_zio_stats(dsl_scan_io_queue_t *q, const blkptr_t *bp)
2781 uint64_t cur_size = 0;
2783 for (i = 0; i < BP_GET_NDVAS(bp); i++) {
2784 cur_size += DVA_GET_ASIZE(&bp->blk_dva[i]);
2787 q->q_total_zio_size_this_txg += cur_size;
2788 q->q_zios_this_txg++;
2792 scan_io_queues_update_seg_stats(dsl_scan_io_queue_t *q, uint64_t start,
2795 q->q_total_seg_size_this_txg += end - start;
2796 q->q_segs_this_txg++;
2800 scan_io_queue_check_suspend(dsl_scan_t *scn)
2802 /* See comment in dsl_scan_check_suspend() */
2803 uint64_t curr_time_ns = gethrtime();
2804 uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time;
2805 uint64_t sync_time_ns = curr_time_ns -
2806 scn->scn_dp->dp_spa->spa_sync_starttime;
2807 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
2808 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
2809 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
2811 return ((NSEC2MSEC(scan_time_ns) > mintime &&
2812 (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent ||
2813 txg_sync_waiting(scn->scn_dp) ||
2814 NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) ||
2815 spa_shutting_down(scn->scn_dp->dp_spa));
2819 * Given a list of scan_io_t's in io_list, this issues the I/Os out to
2820 * disk. This consumes the io_list and frees the scan_io_t's. This is
2821 * called when emptying queues, either when we're up against the memory
2822 * limit or when we have finished scanning. Returns B_TRUE if we stopped
2823 * processing the list before we finished. Any sios that were not issued
2824 * will remain in the io_list.
2827 scan_io_queue_issue(dsl_scan_io_queue_t *queue, list_t *io_list)
2829 dsl_scan_t *scn = queue->q_scn;
2831 int64_t bytes_issued = 0;
2832 boolean_t suspended = B_FALSE;
2834 while ((sio = list_head(io_list)) != NULL) {
2837 if (scan_io_queue_check_suspend(scn)) {
2843 bytes_issued += SIO_GET_ASIZE(sio);
2844 scan_exec_io(scn->scn_dp, &bp, sio->sio_flags,
2845 &sio->sio_zb, queue);
2846 (void) list_remove_head(io_list);
2847 scan_io_queues_update_zio_stats(queue, &bp);
2851 atomic_add_64(&scn->scn_bytes_pending, -bytes_issued);
2857 * This function removes sios from an IO queue which reside within a given
2858 * range_seg_t and inserts them (in offset order) into a list. Note that
2859 * we only ever return a maximum of 32 sios at once. If there are more sios
2860 * to process within this segment that did not make it onto the list we
2861 * return B_TRUE and otherwise B_FALSE.
2864 scan_io_queue_gather(dsl_scan_io_queue_t *queue, range_seg_t *rs, list_t *list)
2866 scan_io_t *srch_sio, *sio, *next_sio;
2868 uint_t num_sios = 0;
2869 int64_t bytes_issued = 0;
2872 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
2874 srch_sio = sio_alloc(1);
2875 srch_sio->sio_nr_dvas = 1;
2876 SIO_SET_OFFSET(srch_sio, rs_get_start(rs, queue->q_exts_by_addr));
2879 * The exact start of the extent might not contain any matching zios,
2880 * so if that's the case, examine the next one in the tree.
2882 sio = avl_find(&queue->q_sios_by_addr, srch_sio, &idx);
2886 sio = avl_nearest(&queue->q_sios_by_addr, idx, AVL_AFTER);
2888 while (sio != NULL && SIO_GET_OFFSET(sio) < rs_get_end(rs,
2889 queue->q_exts_by_addr) && num_sios <= 32) {
2890 ASSERT3U(SIO_GET_OFFSET(sio), >=, rs_get_start(rs,
2891 queue->q_exts_by_addr));
2892 ASSERT3U(SIO_GET_END_OFFSET(sio), <=, rs_get_end(rs,
2893 queue->q_exts_by_addr));
2895 next_sio = AVL_NEXT(&queue->q_sios_by_addr, sio);
2896 avl_remove(&queue->q_sios_by_addr, sio);
2897 queue->q_sio_memused -= SIO_GET_MUSED(sio);
2899 bytes_issued += SIO_GET_ASIZE(sio);
2901 list_insert_tail(list, sio);
2906 * We limit the number of sios we process at once to 32 to avoid
2907 * biting off more than we can chew. If we didn't take everything
2908 * in the segment we update it to reflect the work we were able to
2909 * complete. Otherwise, we remove it from the range tree entirely.
2911 if (sio != NULL && SIO_GET_OFFSET(sio) < rs_get_end(rs,
2912 queue->q_exts_by_addr)) {
2913 range_tree_adjust_fill(queue->q_exts_by_addr, rs,
2915 range_tree_resize_segment(queue->q_exts_by_addr, rs,
2916 SIO_GET_OFFSET(sio), rs_get_end(rs,
2917 queue->q_exts_by_addr) - SIO_GET_OFFSET(sio));
2921 uint64_t rstart = rs_get_start(rs, queue->q_exts_by_addr);
2922 uint64_t rend = rs_get_end(rs, queue->q_exts_by_addr);
2923 range_tree_remove(queue->q_exts_by_addr, rstart, rend - rstart);
2929 * This is called from the queue emptying thread and selects the next
2930 * extent from which we are to issue I/Os. The behavior of this function
2931 * depends on the state of the scan, the current memory consumption and
2932 * whether or not we are performing a scan shutdown.
2933 * 1) We select extents in an elevator algorithm (LBA-order) if the scan
2934 * needs to perform a checkpoint
2935 * 2) We select the largest available extent if we are up against the
2937 * 3) Otherwise we don't select any extents.
2939 static range_seg_t *
2940 scan_io_queue_fetch_ext(dsl_scan_io_queue_t *queue)
2942 dsl_scan_t *scn = queue->q_scn;
2943 range_tree_t *rt = queue->q_exts_by_addr;
2945 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
2946 ASSERT(scn->scn_is_sorted);
2948 /* handle tunable overrides */
2949 if (scn->scn_checkpointing || scn->scn_clearing) {
2950 if (zfs_scan_issue_strategy == 1) {
2951 return (range_tree_first(rt));
2952 } else if (zfs_scan_issue_strategy == 2) {
2954 * We need to get the original entry in the by_addr
2955 * tree so we can modify it.
2957 range_seg_t *size_rs =
2958 zfs_btree_first(&queue->q_exts_by_size, NULL);
2959 if (size_rs == NULL)
2961 uint64_t start = rs_get_start(size_rs, rt);
2962 uint64_t size = rs_get_end(size_rs, rt) - start;
2963 range_seg_t *addr_rs = range_tree_find(rt, start,
2965 ASSERT3P(addr_rs, !=, NULL);
2966 ASSERT3U(rs_get_start(size_rs, rt), ==,
2967 rs_get_start(addr_rs, rt));
2968 ASSERT3U(rs_get_end(size_rs, rt), ==,
2969 rs_get_end(addr_rs, rt));
2975 * During normal clearing, we want to issue our largest segments
2976 * first, keeping IO as sequential as possible, and leaving the
2977 * smaller extents for later with the hope that they might eventually
2978 * grow to larger sequential segments. However, when the scan is
2979 * checkpointing, no new extents will be added to the sorting queue,
2980 * so the way we are sorted now is as good as it will ever get.
2981 * In this case, we instead switch to issuing extents in LBA order.
2983 if (scn->scn_checkpointing) {
2984 return (range_tree_first(rt));
2985 } else if (scn->scn_clearing) {
2987 * We need to get the original entry in the by_addr
2988 * tree so we can modify it.
2990 range_seg_t *size_rs = zfs_btree_first(&queue->q_exts_by_size,
2992 if (size_rs == NULL)
2994 uint64_t start = rs_get_start(size_rs, rt);
2995 uint64_t size = rs_get_end(size_rs, rt) - start;
2996 range_seg_t *addr_rs = range_tree_find(rt, start, size);
2997 ASSERT3P(addr_rs, !=, NULL);
2998 ASSERT3U(rs_get_start(size_rs, rt), ==, rs_get_start(addr_rs,
3000 ASSERT3U(rs_get_end(size_rs, rt), ==, rs_get_end(addr_rs, rt));
3008 scan_io_queues_run_one(void *arg)
3010 dsl_scan_io_queue_t *queue = arg;
3011 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock;
3012 boolean_t suspended = B_FALSE;
3013 range_seg_t *rs = NULL;
3014 scan_io_t *sio = NULL;
3016 uint64_t bytes_per_leaf = zfs_scan_vdev_limit;
3017 uint64_t nr_leaves = dsl_scan_count_leaves(queue->q_vd);
3019 ASSERT(queue->q_scn->scn_is_sorted);
3021 list_create(&sio_list, sizeof (scan_io_t),
3022 offsetof(scan_io_t, sio_nodes.sio_list_node));
3023 mutex_enter(q_lock);
3025 /* calculate maximum in-flight bytes for this txg (min 1MB) */
3026 queue->q_maxinflight_bytes =
3027 MAX(nr_leaves * bytes_per_leaf, 1ULL << 20);
3029 /* reset per-queue scan statistics for this txg */
3030 queue->q_total_seg_size_this_txg = 0;
3031 queue->q_segs_this_txg = 0;
3032 queue->q_total_zio_size_this_txg = 0;
3033 queue->q_zios_this_txg = 0;
3035 /* loop until we run out of time or sios */
3036 while ((rs = scan_io_queue_fetch_ext(queue)) != NULL) {
3037 uint64_t seg_start = 0, seg_end = 0;
3038 boolean_t more_left = B_TRUE;
3040 ASSERT(list_is_empty(&sio_list));
3042 /* loop while we still have sios left to process in this rs */
3044 scan_io_t *first_sio, *last_sio;
3047 * We have selected which extent needs to be
3048 * processed next. Gather up the corresponding sios.
3050 more_left = scan_io_queue_gather(queue, rs, &sio_list);
3051 ASSERT(!list_is_empty(&sio_list));
3052 first_sio = list_head(&sio_list);
3053 last_sio = list_tail(&sio_list);
3055 seg_end = SIO_GET_END_OFFSET(last_sio);
3057 seg_start = SIO_GET_OFFSET(first_sio);
3060 * Issuing sios can take a long time so drop the
3061 * queue lock. The sio queue won't be updated by
3062 * other threads since we're in syncing context so
3063 * we can be sure that our trees will remain exactly
3067 suspended = scan_io_queue_issue(queue, &sio_list);
3068 mutex_enter(q_lock);
3074 /* update statistics for debugging purposes */
3075 scan_io_queues_update_seg_stats(queue, seg_start, seg_end);
3082 * If we were suspended in the middle of processing,
3083 * requeue any unfinished sios and exit.
3085 while ((sio = list_head(&sio_list)) != NULL) {
3086 list_remove(&sio_list, sio);
3087 scan_io_queue_insert_impl(queue, sio);
3091 list_destroy(&sio_list);
3095 * Performs an emptying run on all scan queues in the pool. This just
3096 * punches out one thread per top-level vdev, each of which processes
3097 * only that vdev's scan queue. We can parallelize the I/O here because
3098 * we know that each queue's I/Os only affect its own top-level vdev.
3100 * This function waits for the queue runs to complete, and must be
3101 * called from dsl_scan_sync (or in general, syncing context).
3104 scan_io_queues_run(dsl_scan_t *scn)
3106 spa_t *spa = scn->scn_dp->dp_spa;
3108 ASSERT(scn->scn_is_sorted);
3109 ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
3111 if (scn->scn_bytes_pending == 0)
3114 if (scn->scn_taskq == NULL) {
3115 int nthreads = spa->spa_root_vdev->vdev_children;
3118 * We need to make this taskq *always* execute as many
3119 * threads in parallel as we have top-level vdevs and no
3120 * less, otherwise strange serialization of the calls to
3121 * scan_io_queues_run_one can occur during spa_sync runs
3122 * and that significantly impacts performance.
3124 scn->scn_taskq = taskq_create("dsl_scan_iss", nthreads,
3125 minclsyspri, nthreads, nthreads, TASKQ_PREPOPULATE);
3128 for (uint64_t i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
3129 vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
3131 mutex_enter(&vd->vdev_scan_io_queue_lock);
3132 if (vd->vdev_scan_io_queue != NULL) {
3133 VERIFY(taskq_dispatch(scn->scn_taskq,
3134 scan_io_queues_run_one, vd->vdev_scan_io_queue,
3135 TQ_SLEEP) != TASKQID_INVALID);
3137 mutex_exit(&vd->vdev_scan_io_queue_lock);
3141 * Wait for the queues to finish issuing their IOs for this run
3142 * before we return. There may still be IOs in flight at this
3145 taskq_wait(scn->scn_taskq);
3149 dsl_scan_async_block_should_pause(dsl_scan_t *scn)
3151 uint64_t elapsed_nanosecs;
3156 if (zfs_async_block_max_blocks != 0 &&
3157 scn->scn_visited_this_txg >= zfs_async_block_max_blocks) {
3161 if (zfs_max_async_dedup_frees != 0 &&
3162 scn->scn_dedup_frees_this_txg >= zfs_max_async_dedup_frees) {
3166 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
3167 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
3168 (NSEC2MSEC(elapsed_nanosecs) > scn->scn_async_block_min_time_ms &&
3169 txg_sync_waiting(scn->scn_dp)) ||
3170 spa_shutting_down(scn->scn_dp->dp_spa));
3174 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
3176 dsl_scan_t *scn = arg;
3178 if (!scn->scn_is_bptree ||
3179 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
3180 if (dsl_scan_async_block_should_pause(scn))
3181 return (SET_ERROR(ERESTART));
3184 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
3185 dmu_tx_get_txg(tx), bp, 0));
3186 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
3187 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
3188 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
3189 scn->scn_visited_this_txg++;
3190 if (BP_GET_DEDUP(bp))
3191 scn->scn_dedup_frees_this_txg++;
3196 dsl_scan_update_stats(dsl_scan_t *scn)
3198 spa_t *spa = scn->scn_dp->dp_spa;
3200 uint64_t seg_size_total = 0, zio_size_total = 0;
3201 uint64_t seg_count_total = 0, zio_count_total = 0;
3203 for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
3204 vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
3205 dsl_scan_io_queue_t *queue = vd->vdev_scan_io_queue;
3210 seg_size_total += queue->q_total_seg_size_this_txg;
3211 zio_size_total += queue->q_total_zio_size_this_txg;
3212 seg_count_total += queue->q_segs_this_txg;
3213 zio_count_total += queue->q_zios_this_txg;
3216 if (seg_count_total == 0 || zio_count_total == 0) {
3217 scn->scn_avg_seg_size_this_txg = 0;
3218 scn->scn_avg_zio_size_this_txg = 0;
3219 scn->scn_segs_this_txg = 0;
3220 scn->scn_zios_this_txg = 0;
3224 scn->scn_avg_seg_size_this_txg = seg_size_total / seg_count_total;
3225 scn->scn_avg_zio_size_this_txg = zio_size_total / zio_count_total;
3226 scn->scn_segs_this_txg = seg_count_total;
3227 scn->scn_zios_this_txg = zio_count_total;
3231 bpobj_dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
3235 return (dsl_scan_free_block_cb(arg, bp, tx));
3239 dsl_scan_obsolete_block_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
3243 dsl_scan_t *scn = arg;
3244 const dva_t *dva = &bp->blk_dva[0];
3246 if (dsl_scan_async_block_should_pause(scn))
3247 return (SET_ERROR(ERESTART));
3249 spa_vdev_indirect_mark_obsolete(scn->scn_dp->dp_spa,
3250 DVA_GET_VDEV(dva), DVA_GET_OFFSET(dva),
3251 DVA_GET_ASIZE(dva), tx);
3252 scn->scn_visited_this_txg++;
3257 dsl_scan_active(dsl_scan_t *scn)
3259 spa_t *spa = scn->scn_dp->dp_spa;
3260 uint64_t used = 0, comp, uncomp;
3261 boolean_t clones_left;
3263 if (spa->spa_load_state != SPA_LOAD_NONE)
3265 if (spa_shutting_down(spa))
3267 if ((dsl_scan_is_running(scn) && !dsl_scan_is_paused_scrub(scn)) ||
3268 (scn->scn_async_destroying && !scn->scn_async_stalled))
3271 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
3272 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
3273 &used, &comp, &uncomp);
3275 clones_left = spa_livelist_delete_check(spa);
3276 return ((used != 0) || (clones_left));
3280 dsl_scan_check_deferred(vdev_t *vd)
3282 boolean_t need_resilver = B_FALSE;
3284 for (int c = 0; c < vd->vdev_children; c++) {
3286 dsl_scan_check_deferred(vd->vdev_child[c]);
3289 if (!vdev_is_concrete(vd) || vd->vdev_aux ||
3290 !vd->vdev_ops->vdev_op_leaf)
3291 return (need_resilver);
3293 if (!vd->vdev_resilver_deferred)
3294 need_resilver = B_TRUE;
3296 return (need_resilver);
3300 dsl_scan_need_resilver(spa_t *spa, const dva_t *dva, size_t psize,
3301 uint64_t phys_birth)
3305 vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
3307 if (vd->vdev_ops == &vdev_indirect_ops) {
3309 * The indirect vdev can point to multiple
3310 * vdevs. For simplicity, always create
3311 * the resilver zio_t. zio_vdev_io_start()
3312 * will bypass the child resilver i/o's if
3313 * they are on vdevs that don't have DTL's.
3318 if (DVA_GET_GANG(dva)) {
3320 * Gang members may be spread across multiple
3321 * vdevs, so the best estimate we have is the
3322 * scrub range, which has already been checked.
3323 * XXX -- it would be better to change our
3324 * allocation policy to ensure that all
3325 * gang members reside on the same vdev.
3331 * Check if the txg falls within the range which must be
3332 * resilvered. DVAs outside this range can always be skipped.
3334 if (!vdev_dtl_contains(vd, DTL_PARTIAL, phys_birth, 1))
3338 * Check if the top-level vdev must resilver this offset.
3339 * When the offset does not intersect with a dirty leaf DTL
3340 * then it may be possible to skip the resilver IO. The psize
3341 * is provided instead of asize to simplify the check for RAIDZ.
3343 if (!vdev_dtl_need_resilver(vd, DVA_GET_OFFSET(dva), psize))
3347 * Check that this top-level vdev has a device under it which
3348 * is resilvering and is not deferred.
3350 if (!dsl_scan_check_deferred(vd))
3357 dsl_process_async_destroys(dsl_pool_t *dp, dmu_tx_t *tx)
3359 dsl_scan_t *scn = dp->dp_scan;
3360 spa_t *spa = dp->dp_spa;
3363 if (spa_suspend_async_destroy(spa))
3366 if (zfs_free_bpobj_enabled &&
3367 spa_version(spa) >= SPA_VERSION_DEADLISTS) {
3368 scn->scn_is_bptree = B_FALSE;
3369 scn->scn_async_block_min_time_ms = zfs_free_min_time_ms;
3370 scn->scn_zio_root = zio_root(spa, NULL,
3371 NULL, ZIO_FLAG_MUSTSUCCEED);
3372 err = bpobj_iterate(&dp->dp_free_bpobj,
3373 bpobj_dsl_scan_free_block_cb, scn, tx);
3374 VERIFY0(zio_wait(scn->scn_zio_root));
3375 scn->scn_zio_root = NULL;
3377 if (err != 0 && err != ERESTART)
3378 zfs_panic_recover("error %u from bpobj_iterate()", err);
3381 if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) {
3382 ASSERT(scn->scn_async_destroying);
3383 scn->scn_is_bptree = B_TRUE;
3384 scn->scn_zio_root = zio_root(spa, NULL,
3385 NULL, ZIO_FLAG_MUSTSUCCEED);
3386 err = bptree_iterate(dp->dp_meta_objset,
3387 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx);
3388 VERIFY0(zio_wait(scn->scn_zio_root));
3389 scn->scn_zio_root = NULL;
3391 if (err == EIO || err == ECKSUM) {
3393 } else if (err != 0 && err != ERESTART) {
3394 zfs_panic_recover("error %u from "
3395 "traverse_dataset_destroyed()", err);
3398 if (bptree_is_empty(dp->dp_meta_objset, dp->dp_bptree_obj)) {
3399 /* finished; deactivate async destroy feature */
3400 spa_feature_decr(spa, SPA_FEATURE_ASYNC_DESTROY, tx);
3401 ASSERT(!spa_feature_is_active(spa,
3402 SPA_FEATURE_ASYNC_DESTROY));
3403 VERIFY0(zap_remove(dp->dp_meta_objset,
3404 DMU_POOL_DIRECTORY_OBJECT,
3405 DMU_POOL_BPTREE_OBJ, tx));
3406 VERIFY0(bptree_free(dp->dp_meta_objset,
3407 dp->dp_bptree_obj, tx));
3408 dp->dp_bptree_obj = 0;
3409 scn->scn_async_destroying = B_FALSE;
3410 scn->scn_async_stalled = B_FALSE;
3413 * If we didn't make progress, mark the async
3414 * destroy as stalled, so that we will not initiate
3415 * a spa_sync() on its behalf. Note that we only
3416 * check this if we are not finished, because if the
3417 * bptree had no blocks for us to visit, we can
3418 * finish without "making progress".
3420 scn->scn_async_stalled =
3421 (scn->scn_visited_this_txg == 0);
3424 if (scn->scn_visited_this_txg) {
3425 zfs_dbgmsg("freed %llu blocks in %llums from "
3426 "free_bpobj/bptree txg %llu; err=%u",
3427 (longlong_t)scn->scn_visited_this_txg,
3429 NSEC2MSEC(gethrtime() - scn->scn_sync_start_time),
3430 (longlong_t)tx->tx_txg, err);
3431 scn->scn_visited_this_txg = 0;
3432 scn->scn_dedup_frees_this_txg = 0;
3435 * Write out changes to the DDT that may be required as a
3436 * result of the blocks freed. This ensures that the DDT
3437 * is clean when a scrub/resilver runs.
3439 ddt_sync(spa, tx->tx_txg);
3443 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying &&
3444 zfs_free_leak_on_eio &&
3445 (dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes != 0 ||
3446 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes != 0 ||
3447 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes != 0)) {
3449 * We have finished background destroying, but there is still
3450 * some space left in the dp_free_dir. Transfer this leaked
3451 * space to the dp_leak_dir.
3453 if (dp->dp_leak_dir == NULL) {
3454 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
3455 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
3457 VERIFY0(dsl_pool_open_special_dir(dp,
3458 LEAK_DIR_NAME, &dp->dp_leak_dir));
3459 rrw_exit(&dp->dp_config_rwlock, FTAG);
3461 dsl_dir_diduse_space(dp->dp_leak_dir, DD_USED_HEAD,
3462 dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
3463 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
3464 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
3465 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
3466 -dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
3467 -dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
3468 -dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
3471 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying &&
3472 !spa_livelist_delete_check(spa)) {
3473 /* finished; verify that space accounting went to zero */
3474 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes);
3475 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes);
3476 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes);
3479 spa_notify_waiters(spa);
3481 EQUIV(bpobj_is_open(&dp->dp_obsolete_bpobj),
3482 0 == zap_contains(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
3483 DMU_POOL_OBSOLETE_BPOBJ));
3484 if (err == 0 && bpobj_is_open(&dp->dp_obsolete_bpobj)) {
3485 ASSERT(spa_feature_is_active(dp->dp_spa,
3486 SPA_FEATURE_OBSOLETE_COUNTS));
3488 scn->scn_is_bptree = B_FALSE;
3489 scn->scn_async_block_min_time_ms = zfs_obsolete_min_time_ms;
3490 err = bpobj_iterate(&dp->dp_obsolete_bpobj,
3491 dsl_scan_obsolete_block_cb, scn, tx);
3492 if (err != 0 && err != ERESTART)
3493 zfs_panic_recover("error %u from bpobj_iterate()", err);
3495 if (bpobj_is_empty(&dp->dp_obsolete_bpobj))
3496 dsl_pool_destroy_obsolete_bpobj(dp, tx);
3502 * This is the primary entry point for scans that is called from syncing
3503 * context. Scans must happen entirely during syncing context so that we
3504 * can guarantee that blocks we are currently scanning will not change out
3505 * from under us. While a scan is active, this function controls how quickly
3506 * transaction groups proceed, instead of the normal handling provided by
3507 * txg_sync_thread().
3510 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
3513 dsl_scan_t *scn = dp->dp_scan;
3514 spa_t *spa = dp->dp_spa;
3515 state_sync_type_t sync_type = SYNC_OPTIONAL;
3517 if (spa->spa_resilver_deferred &&
3518 !spa_feature_is_active(dp->dp_spa, SPA_FEATURE_RESILVER_DEFER))
3519 spa_feature_incr(spa, SPA_FEATURE_RESILVER_DEFER, tx);
3522 * Check for scn_restart_txg before checking spa_load_state, so
3523 * that we can restart an old-style scan while the pool is being
3524 * imported (see dsl_scan_init). We also restart scans if there
3525 * is a deferred resilver and the user has manually disabled
3526 * deferred resilvers via the tunable.
3528 if (dsl_scan_restarting(scn, tx) ||
3529 (spa->spa_resilver_deferred && zfs_resilver_disable_defer)) {
3530 pool_scan_func_t func = POOL_SCAN_SCRUB;
3531 dsl_scan_done(scn, B_FALSE, tx);
3532 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
3533 func = POOL_SCAN_RESILVER;
3534 zfs_dbgmsg("restarting scan func=%u txg=%llu",
3535 func, (longlong_t)tx->tx_txg);
3536 dsl_scan_setup_sync(&func, tx);
3540 * Only process scans in sync pass 1.
3542 if (spa_sync_pass(spa) > 1)
3546 * If the spa is shutting down, then stop scanning. This will
3547 * ensure that the scan does not dirty any new data during the
3550 if (spa_shutting_down(spa))
3554 * If the scan is inactive due to a stalled async destroy, try again.
3556 if (!scn->scn_async_stalled && !dsl_scan_active(scn))
3559 /* reset scan statistics */
3560 scn->scn_visited_this_txg = 0;
3561 scn->scn_dedup_frees_this_txg = 0;
3562 scn->scn_holes_this_txg = 0;
3563 scn->scn_lt_min_this_txg = 0;
3564 scn->scn_gt_max_this_txg = 0;
3565 scn->scn_ddt_contained_this_txg = 0;
3566 scn->scn_objsets_visited_this_txg = 0;
3567 scn->scn_avg_seg_size_this_txg = 0;
3568 scn->scn_segs_this_txg = 0;
3569 scn->scn_avg_zio_size_this_txg = 0;
3570 scn->scn_zios_this_txg = 0;
3571 scn->scn_suspending = B_FALSE;
3572 scn->scn_sync_start_time = gethrtime();
3573 spa->spa_scrub_active = B_TRUE;
3576 * First process the async destroys. If we suspend, don't do
3577 * any scrubbing or resilvering. This ensures that there are no
3578 * async destroys while we are scanning, so the scan code doesn't
3579 * have to worry about traversing it. It is also faster to free the
3580 * blocks than to scrub them.
3582 err = dsl_process_async_destroys(dp, tx);
3586 if (!dsl_scan_is_running(scn) || dsl_scan_is_paused_scrub(scn))
3590 * Wait a few txgs after importing to begin scanning so that
3591 * we can get the pool imported quickly.
3593 if (spa->spa_syncing_txg < spa->spa_first_txg + SCAN_IMPORT_WAIT_TXGS)
3597 * zfs_scan_suspend_progress can be set to disable scan progress.
3598 * We don't want to spin the txg_sync thread, so we add a delay
3599 * here to simulate the time spent doing a scan. This is mostly
3600 * useful for testing and debugging.
3602 if (zfs_scan_suspend_progress) {
3603 uint64_t scan_time_ns = gethrtime() - scn->scn_sync_start_time;
3604 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
3605 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
3607 while (zfs_scan_suspend_progress &&
3608 !txg_sync_waiting(scn->scn_dp) &&
3609 !spa_shutting_down(scn->scn_dp->dp_spa) &&
3610 NSEC2MSEC(scan_time_ns) < mintime) {
3612 scan_time_ns = gethrtime() - scn->scn_sync_start_time;
3618 * It is possible to switch from unsorted to sorted at any time,
3619 * but afterwards the scan will remain sorted unless reloaded from
3620 * a checkpoint after a reboot.
3622 if (!zfs_scan_legacy) {
3623 scn->scn_is_sorted = B_TRUE;
3624 if (scn->scn_last_checkpoint == 0)
3625 scn->scn_last_checkpoint = ddi_get_lbolt();
3629 * For sorted scans, determine what kind of work we will be doing
3630 * this txg based on our memory limitations and whether or not we
3631 * need to perform a checkpoint.
3633 if (scn->scn_is_sorted) {
3635 * If we are over our checkpoint interval, set scn_clearing
3636 * so that we can begin checkpointing immediately. The
3637 * checkpoint allows us to save a consistent bookmark
3638 * representing how much data we have scrubbed so far.
3639 * Otherwise, use the memory limit to determine if we should
3640 * scan for metadata or start issue scrub IOs. We accumulate
3641 * metadata until we hit our hard memory limit at which point
3642 * we issue scrub IOs until we are at our soft memory limit.
3644 if (scn->scn_checkpointing ||
3645 ddi_get_lbolt() - scn->scn_last_checkpoint >
3646 SEC_TO_TICK(zfs_scan_checkpoint_intval)) {
3647 if (!scn->scn_checkpointing)
3648 zfs_dbgmsg("begin scan checkpoint");
3650 scn->scn_checkpointing = B_TRUE;
3651 scn->scn_clearing = B_TRUE;
3653 boolean_t should_clear = dsl_scan_should_clear(scn);
3654 if (should_clear && !scn->scn_clearing) {
3655 zfs_dbgmsg("begin scan clearing");
3656 scn->scn_clearing = B_TRUE;
3657 } else if (!should_clear && scn->scn_clearing) {
3658 zfs_dbgmsg("finish scan clearing");
3659 scn->scn_clearing = B_FALSE;
3663 ASSERT0(scn->scn_checkpointing);
3664 ASSERT0(scn->scn_clearing);
3667 if (!scn->scn_clearing && scn->scn_done_txg == 0) {
3668 /* Need to scan metadata for more blocks to scrub */
3669 dsl_scan_phys_t *scnp = &scn->scn_phys;
3670 taskqid_t prefetch_tqid;
3671 uint64_t bytes_per_leaf = zfs_scan_vdev_limit;
3672 uint64_t nr_leaves = dsl_scan_count_leaves(spa->spa_root_vdev);
3675 * Recalculate the max number of in-flight bytes for pool-wide
3676 * scanning operations (minimum 1MB). Limits for the issuing
3677 * phase are done per top-level vdev and are handled separately.
3679 scn->scn_maxinflight_bytes =
3680 MAX(nr_leaves * bytes_per_leaf, 1ULL << 20);
3682 if (scnp->scn_ddt_bookmark.ddb_class <=
3683 scnp->scn_ddt_class_max) {
3684 ASSERT(ZB_IS_ZERO(&scnp->scn_bookmark));
3685 zfs_dbgmsg("doing scan sync txg %llu; "
3686 "ddt bm=%llu/%llu/%llu/%llx",
3687 (longlong_t)tx->tx_txg,
3688 (longlong_t)scnp->scn_ddt_bookmark.ddb_class,
3689 (longlong_t)scnp->scn_ddt_bookmark.ddb_type,
3690 (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum,
3691 (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor);
3693 zfs_dbgmsg("doing scan sync txg %llu; "
3694 "bm=%llu/%llu/%llu/%llu",
3695 (longlong_t)tx->tx_txg,
3696 (longlong_t)scnp->scn_bookmark.zb_objset,
3697 (longlong_t)scnp->scn_bookmark.zb_object,
3698 (longlong_t)scnp->scn_bookmark.zb_level,
3699 (longlong_t)scnp->scn_bookmark.zb_blkid);
3702 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
3703 NULL, ZIO_FLAG_CANFAIL);
3705 scn->scn_prefetch_stop = B_FALSE;
3706 prefetch_tqid = taskq_dispatch(dp->dp_sync_taskq,
3707 dsl_scan_prefetch_thread, scn, TQ_SLEEP);
3708 ASSERT(prefetch_tqid != TASKQID_INVALID);
3710 dsl_pool_config_enter(dp, FTAG);
3711 dsl_scan_visit(scn, tx);
3712 dsl_pool_config_exit(dp, FTAG);
3714 mutex_enter(&dp->dp_spa->spa_scrub_lock);
3715 scn->scn_prefetch_stop = B_TRUE;
3716 cv_broadcast(&spa->spa_scrub_io_cv);
3717 mutex_exit(&dp->dp_spa->spa_scrub_lock);
3719 taskq_wait_id(dp->dp_sync_taskq, prefetch_tqid);
3720 (void) zio_wait(scn->scn_zio_root);
3721 scn->scn_zio_root = NULL;
3723 zfs_dbgmsg("scan visited %llu blocks in %llums "
3724 "(%llu os's, %llu holes, %llu < mintxg, "
3725 "%llu in ddt, %llu > maxtxg)",
3726 (longlong_t)scn->scn_visited_this_txg,
3727 (longlong_t)NSEC2MSEC(gethrtime() -
3728 scn->scn_sync_start_time),
3729 (longlong_t)scn->scn_objsets_visited_this_txg,
3730 (longlong_t)scn->scn_holes_this_txg,
3731 (longlong_t)scn->scn_lt_min_this_txg,
3732 (longlong_t)scn->scn_ddt_contained_this_txg,
3733 (longlong_t)scn->scn_gt_max_this_txg);
3735 if (!scn->scn_suspending) {
3736 ASSERT0(avl_numnodes(&scn->scn_queue));
3737 scn->scn_done_txg = tx->tx_txg + 1;
3738 if (scn->scn_is_sorted) {
3739 scn->scn_checkpointing = B_TRUE;
3740 scn->scn_clearing = B_TRUE;
3742 zfs_dbgmsg("scan complete txg %llu",
3743 (longlong_t)tx->tx_txg);
3745 } else if (scn->scn_is_sorted && scn->scn_bytes_pending != 0) {
3746 ASSERT(scn->scn_clearing);
3748 /* need to issue scrubbing IOs from per-vdev queues */
3749 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
3750 NULL, ZIO_FLAG_CANFAIL);
3751 scan_io_queues_run(scn);
3752 (void) zio_wait(scn->scn_zio_root);
3753 scn->scn_zio_root = NULL;
3755 /* calculate and dprintf the current memory usage */
3756 (void) dsl_scan_should_clear(scn);
3757 dsl_scan_update_stats(scn);
3759 zfs_dbgmsg("scan issued %llu blocks (%llu segs) in %llums "
3760 "(avg_block_size = %llu, avg_seg_size = %llu)",
3761 (longlong_t)scn->scn_zios_this_txg,
3762 (longlong_t)scn->scn_segs_this_txg,
3763 (longlong_t)NSEC2MSEC(gethrtime() -
3764 scn->scn_sync_start_time),
3765 (longlong_t)scn->scn_avg_zio_size_this_txg,
3766 (longlong_t)scn->scn_avg_seg_size_this_txg);
3767 } else if (scn->scn_done_txg != 0 && scn->scn_done_txg <= tx->tx_txg) {
3768 /* Finished with everything. Mark the scrub as complete */
3769 zfs_dbgmsg("scan issuing complete txg %llu",
3770 (longlong_t)tx->tx_txg);
3771 ASSERT3U(scn->scn_done_txg, !=, 0);
3772 ASSERT0(spa->spa_scrub_inflight);
3773 ASSERT0(scn->scn_bytes_pending);
3774 dsl_scan_done(scn, B_TRUE, tx);
3775 sync_type = SYNC_MANDATORY;
3778 dsl_scan_sync_state(scn, tx, sync_type);
3782 count_block(dsl_scan_t *scn, zfs_all_blkstats_t *zab, const blkptr_t *bp)
3787 * Don't count embedded bp's, since we already did the work of
3788 * scanning these when we scanned the containing block.
3790 if (BP_IS_EMBEDDED(bp))
3794 * Update the spa's stats on how many bytes we have issued.
3795 * Sequential scrubs create a zio for each DVA of the bp. Each
3796 * of these will include all DVAs for repair purposes, but the
3797 * zio code will only try the first one unless there is an issue.
3798 * Therefore, we should only count the first DVA for these IOs.
3800 if (scn->scn_is_sorted) {
3801 atomic_add_64(&scn->scn_dp->dp_spa->spa_scan_pass_issued,
3802 DVA_GET_ASIZE(&bp->blk_dva[0]));
3804 spa_t *spa = scn->scn_dp->dp_spa;
3806 for (i = 0; i < BP_GET_NDVAS(bp); i++) {
3807 atomic_add_64(&spa->spa_scan_pass_issued,
3808 DVA_GET_ASIZE(&bp->blk_dva[i]));
3813 * If we resume after a reboot, zab will be NULL; don't record
3814 * incomplete stats in that case.
3819 mutex_enter(&zab->zab_lock);
3821 for (i = 0; i < 4; i++) {
3822 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
3823 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
3825 if (t & DMU_OT_NEWTYPE)
3827 zfs_blkstat_t *zb = &zab->zab_type[l][t];
3831 zb->zb_asize += BP_GET_ASIZE(bp);
3832 zb->zb_lsize += BP_GET_LSIZE(bp);
3833 zb->zb_psize += BP_GET_PSIZE(bp);
3834 zb->zb_gangs += BP_COUNT_GANG(bp);
3836 switch (BP_GET_NDVAS(bp)) {
3838 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
3839 DVA_GET_VDEV(&bp->blk_dva[1]))
3840 zb->zb_ditto_2_of_2_samevdev++;
3843 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
3844 DVA_GET_VDEV(&bp->blk_dva[1])) +
3845 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
3846 DVA_GET_VDEV(&bp->blk_dva[2])) +
3847 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
3848 DVA_GET_VDEV(&bp->blk_dva[2]));
3850 zb->zb_ditto_2_of_3_samevdev++;
3851 else if (equal == 3)
3852 zb->zb_ditto_3_of_3_samevdev++;
3857 mutex_exit(&zab->zab_lock);
3861 scan_io_queue_insert_impl(dsl_scan_io_queue_t *queue, scan_io_t *sio)
3864 int64_t asize = SIO_GET_ASIZE(sio);
3865 dsl_scan_t *scn = queue->q_scn;
3867 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
3869 if (avl_find(&queue->q_sios_by_addr, sio, &idx) != NULL) {
3870 /* block is already scheduled for reading */
3871 atomic_add_64(&scn->scn_bytes_pending, -asize);
3875 avl_insert(&queue->q_sios_by_addr, sio, idx);
3876 queue->q_sio_memused += SIO_GET_MUSED(sio);
3877 range_tree_add(queue->q_exts_by_addr, SIO_GET_OFFSET(sio), asize);
3881 * Given all the info we got from our metadata scanning process, we
3882 * construct a scan_io_t and insert it into the scan sorting queue. The
3883 * I/O must already be suitable for us to process. This is controlled
3884 * by dsl_scan_enqueue().
3887 scan_io_queue_insert(dsl_scan_io_queue_t *queue, const blkptr_t *bp, int dva_i,
3888 int zio_flags, const zbookmark_phys_t *zb)
3890 dsl_scan_t *scn = queue->q_scn;
3891 scan_io_t *sio = sio_alloc(BP_GET_NDVAS(bp));
3893 ASSERT0(BP_IS_GANG(bp));
3894 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
3896 bp2sio(bp, sio, dva_i);
3897 sio->sio_flags = zio_flags;
3901 * Increment the bytes pending counter now so that we can't
3902 * get an integer underflow in case the worker processes the
3903 * zio before we get to incrementing this counter.
3905 atomic_add_64(&scn->scn_bytes_pending, SIO_GET_ASIZE(sio));
3907 scan_io_queue_insert_impl(queue, sio);
3911 * Given a set of I/O parameters as discovered by the metadata traversal
3912 * process, attempts to place the I/O into the sorted queues (if allowed),
3913 * or immediately executes the I/O.
3916 dsl_scan_enqueue(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
3917 const zbookmark_phys_t *zb)
3919 spa_t *spa = dp->dp_spa;
3921 ASSERT(!BP_IS_EMBEDDED(bp));
3924 * Gang blocks are hard to issue sequentially, so we just issue them
3925 * here immediately instead of queuing them.
3927 if (!dp->dp_scan->scn_is_sorted || BP_IS_GANG(bp)) {
3928 scan_exec_io(dp, bp, zio_flags, zb, NULL);
3932 for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
3936 dva = bp->blk_dva[i];
3937 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&dva));
3938 ASSERT(vdev != NULL);
3940 mutex_enter(&vdev->vdev_scan_io_queue_lock);
3941 if (vdev->vdev_scan_io_queue == NULL)
3942 vdev->vdev_scan_io_queue = scan_io_queue_create(vdev);
3943 ASSERT(dp->dp_scan != NULL);
3944 scan_io_queue_insert(vdev->vdev_scan_io_queue, bp,
3946 mutex_exit(&vdev->vdev_scan_io_queue_lock);
3951 dsl_scan_scrub_cb(dsl_pool_t *dp,
3952 const blkptr_t *bp, const zbookmark_phys_t *zb)
3954 dsl_scan_t *scn = dp->dp_scan;
3955 spa_t *spa = dp->dp_spa;
3956 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
3957 size_t psize = BP_GET_PSIZE(bp);
3958 boolean_t needs_io = B_FALSE;
3959 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
3962 if (phys_birth <= scn->scn_phys.scn_min_txg ||
3963 phys_birth >= scn->scn_phys.scn_max_txg) {
3964 count_block(scn, dp->dp_blkstats, bp);
3968 /* Embedded BP's have phys_birth==0, so we reject them above. */
3969 ASSERT(!BP_IS_EMBEDDED(bp));
3971 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
3972 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
3973 zio_flags |= ZIO_FLAG_SCRUB;
3976 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
3977 zio_flags |= ZIO_FLAG_RESILVER;
3981 /* If it's an intent log block, failure is expected. */
3982 if (zb->zb_level == ZB_ZIL_LEVEL)
3983 zio_flags |= ZIO_FLAG_SPECULATIVE;
3985 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
3986 const dva_t *dva = &bp->blk_dva[d];
3989 * Keep track of how much data we've examined so that
3990 * zpool(1M) status can make useful progress reports.
3992 scn->scn_phys.scn_examined += DVA_GET_ASIZE(dva);
3993 spa->spa_scan_pass_exam += DVA_GET_ASIZE(dva);
3995 /* if it's a resilver, this may not be in the target range */
3997 needs_io = dsl_scan_need_resilver(spa, dva, psize,
4001 if (needs_io && !zfs_no_scrub_io) {
4002 dsl_scan_enqueue(dp, bp, zio_flags, zb);
4004 count_block(scn, dp->dp_blkstats, bp);
4007 /* do not relocate this block */
4012 dsl_scan_scrub_done(zio_t *zio)
4014 spa_t *spa = zio->io_spa;
4015 blkptr_t *bp = zio->io_bp;
4016 dsl_scan_io_queue_t *queue = zio->io_private;
4018 abd_free(zio->io_abd);
4020 if (queue == NULL) {
4021 mutex_enter(&spa->spa_scrub_lock);
4022 ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp));
4023 spa->spa_scrub_inflight -= BP_GET_PSIZE(bp);
4024 cv_broadcast(&spa->spa_scrub_io_cv);
4025 mutex_exit(&spa->spa_scrub_lock);
4027 mutex_enter(&queue->q_vd->vdev_scan_io_queue_lock);
4028 ASSERT3U(queue->q_inflight_bytes, >=, BP_GET_PSIZE(bp));
4029 queue->q_inflight_bytes -= BP_GET_PSIZE(bp);
4030 cv_broadcast(&queue->q_zio_cv);
4031 mutex_exit(&queue->q_vd->vdev_scan_io_queue_lock);
4034 if (zio->io_error && (zio->io_error != ECKSUM ||
4035 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
4036 atomic_inc_64(&spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors);
4041 * Given a scanning zio's information, executes the zio. The zio need
4042 * not necessarily be only sortable, this function simply executes the
4043 * zio, no matter what it is. The optional queue argument allows the
4044 * caller to specify that they want per top level vdev IO rate limiting
4045 * instead of the legacy global limiting.
4048 scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
4049 const zbookmark_phys_t *zb, dsl_scan_io_queue_t *queue)
4051 spa_t *spa = dp->dp_spa;
4052 dsl_scan_t *scn = dp->dp_scan;
4053 size_t size = BP_GET_PSIZE(bp);
4054 abd_t *data = abd_alloc_for_io(size, B_FALSE);
4056 ASSERT3U(scn->scn_maxinflight_bytes, >, 0);
4058 if (queue == NULL) {
4059 mutex_enter(&spa->spa_scrub_lock);
4060 while (spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes)
4061 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
4062 spa->spa_scrub_inflight += BP_GET_PSIZE(bp);
4063 mutex_exit(&spa->spa_scrub_lock);
4065 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock;
4067 mutex_enter(q_lock);
4068 while (queue->q_inflight_bytes >= queue->q_maxinflight_bytes)
4069 cv_wait(&queue->q_zio_cv, q_lock);
4070 queue->q_inflight_bytes += BP_GET_PSIZE(bp);
4074 count_block(scn, dp->dp_blkstats, bp);
4075 zio_nowait(zio_read(scn->scn_zio_root, spa, bp, data, size,
4076 dsl_scan_scrub_done, queue, ZIO_PRIORITY_SCRUB, zio_flags, zb));
4080 * This is the primary extent sorting algorithm. We balance two parameters:
4081 * 1) how many bytes of I/O are in an extent
4082 * 2) how well the extent is filled with I/O (as a fraction of its total size)
4083 * Since we allow extents to have gaps between their constituent I/Os, it's
4084 * possible to have a fairly large extent that contains the same amount of
4085 * I/O bytes than a much smaller extent, which just packs the I/O more tightly.
4086 * The algorithm sorts based on a score calculated from the extent's size,
4087 * the relative fill volume (in %) and a "fill weight" parameter that controls
4088 * the split between whether we prefer larger extents or more well populated
4091 * SCORE = FILL_IN_BYTES + (FILL_IN_PERCENT * FILL_IN_BYTES * FILL_WEIGHT)
4094 * 1) assume extsz = 64 MiB
4095 * 2) assume fill = 32 MiB (extent is half full)
4096 * 3) assume fill_weight = 3
4097 * 4) SCORE = 32M + (((32M * 100) / 64M) * 3 * 32M) / 100
4098 * SCORE = 32M + (50 * 3 * 32M) / 100
4099 * SCORE = 32M + (4800M / 100)
4102 * | +--- final total relative fill-based score
4103 * +--------- final total fill-based score
4106 * As can be seen, at fill_ratio=3, the algorithm is slightly biased towards
4107 * extents that are more completely filled (in a 3:2 ratio) vs just larger.
4108 * Note that as an optimization, we replace multiplication and division by
4109 * 100 with bitshifting by 7 (which effectively multiplies and divides by 128).
4112 ext_size_compare(const void *x, const void *y)
4114 const range_seg_gap_t *rsa = x, *rsb = y;
4116 uint64_t sa = rsa->rs_end - rsa->rs_start;
4117 uint64_t sb = rsb->rs_end - rsb->rs_start;
4118 uint64_t score_a, score_b;
4120 score_a = rsa->rs_fill + ((((rsa->rs_fill << 7) / sa) *
4121 fill_weight * rsa->rs_fill) >> 7);
4122 score_b = rsb->rs_fill + ((((rsb->rs_fill << 7) / sb) *
4123 fill_weight * rsb->rs_fill) >> 7);
4125 if (score_a > score_b)
4127 if (score_a == score_b) {
4128 if (rsa->rs_start < rsb->rs_start)
4130 if (rsa->rs_start == rsb->rs_start)
4138 * Comparator for the q_sios_by_addr tree. Sorting is simply performed
4139 * based on LBA-order (from lowest to highest).
4142 sio_addr_compare(const void *x, const void *y)
4144 const scan_io_t *a = x, *b = y;
4146 return (TREE_CMP(SIO_GET_OFFSET(a), SIO_GET_OFFSET(b)));
4149 /* IO queues are created on demand when they are needed. */
4150 static dsl_scan_io_queue_t *
4151 scan_io_queue_create(vdev_t *vd)
4153 dsl_scan_t *scn = vd->vdev_spa->spa_dsl_pool->dp_scan;
4154 dsl_scan_io_queue_t *q = kmem_zalloc(sizeof (*q), KM_SLEEP);
4158 q->q_sio_memused = 0;
4159 cv_init(&q->q_zio_cv, NULL, CV_DEFAULT, NULL);
4160 q->q_exts_by_addr = range_tree_create_impl(&rt_btree_ops, RANGE_SEG_GAP,
4161 &q->q_exts_by_size, 0, 0, ext_size_compare, zfs_scan_max_ext_gap);
4162 avl_create(&q->q_sios_by_addr, sio_addr_compare,
4163 sizeof (scan_io_t), offsetof(scan_io_t, sio_nodes.sio_addr_node));
4169 * Destroys a scan queue and all segments and scan_io_t's contained in it.
4170 * No further execution of I/O occurs, anything pending in the queue is
4171 * simply freed without being executed.
4174 dsl_scan_io_queue_destroy(dsl_scan_io_queue_t *queue)
4176 dsl_scan_t *scn = queue->q_scn;
4178 void *cookie = NULL;
4179 int64_t bytes_dequeued = 0;
4181 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
4183 while ((sio = avl_destroy_nodes(&queue->q_sios_by_addr, &cookie)) !=
4185 ASSERT(range_tree_contains(queue->q_exts_by_addr,
4186 SIO_GET_OFFSET(sio), SIO_GET_ASIZE(sio)));
4187 bytes_dequeued += SIO_GET_ASIZE(sio);
4188 queue->q_sio_memused -= SIO_GET_MUSED(sio);
4192 ASSERT0(queue->q_sio_memused);
4193 atomic_add_64(&scn->scn_bytes_pending, -bytes_dequeued);
4194 range_tree_vacate(queue->q_exts_by_addr, NULL, queue);
4195 range_tree_destroy(queue->q_exts_by_addr);
4196 avl_destroy(&queue->q_sios_by_addr);
4197 cv_destroy(&queue->q_zio_cv);
4199 kmem_free(queue, sizeof (*queue));
4203 * Properly transfers a dsl_scan_queue_t from `svd' to `tvd'. This is
4204 * called on behalf of vdev_top_transfer when creating or destroying
4205 * a mirror vdev due to zpool attach/detach.
4208 dsl_scan_io_queue_vdev_xfer(vdev_t *svd, vdev_t *tvd)
4210 mutex_enter(&svd->vdev_scan_io_queue_lock);
4211 mutex_enter(&tvd->vdev_scan_io_queue_lock);
4213 VERIFY3P(tvd->vdev_scan_io_queue, ==, NULL);
4214 tvd->vdev_scan_io_queue = svd->vdev_scan_io_queue;
4215 svd->vdev_scan_io_queue = NULL;
4216 if (tvd->vdev_scan_io_queue != NULL)
4217 tvd->vdev_scan_io_queue->q_vd = tvd;
4219 mutex_exit(&tvd->vdev_scan_io_queue_lock);
4220 mutex_exit(&svd->vdev_scan_io_queue_lock);
4224 scan_io_queues_destroy(dsl_scan_t *scn)
4226 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
4228 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
4229 vdev_t *tvd = rvd->vdev_child[i];
4231 mutex_enter(&tvd->vdev_scan_io_queue_lock);
4232 if (tvd->vdev_scan_io_queue != NULL)
4233 dsl_scan_io_queue_destroy(tvd->vdev_scan_io_queue);
4234 tvd->vdev_scan_io_queue = NULL;
4235 mutex_exit(&tvd->vdev_scan_io_queue_lock);
4240 dsl_scan_freed_dva(spa_t *spa, const blkptr_t *bp, int dva_i)
4242 dsl_pool_t *dp = spa->spa_dsl_pool;
4243 dsl_scan_t *scn = dp->dp_scan;
4246 dsl_scan_io_queue_t *queue;
4247 scan_io_t *srch_sio, *sio;
4249 uint64_t start, size;
4251 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[dva_i]));
4252 ASSERT(vdev != NULL);
4253 q_lock = &vdev->vdev_scan_io_queue_lock;
4254 queue = vdev->vdev_scan_io_queue;
4256 mutex_enter(q_lock);
4257 if (queue == NULL) {
4262 srch_sio = sio_alloc(BP_GET_NDVAS(bp));
4263 bp2sio(bp, srch_sio, dva_i);
4264 start = SIO_GET_OFFSET(srch_sio);
4265 size = SIO_GET_ASIZE(srch_sio);
4268 * We can find the zio in two states:
4269 * 1) Cold, just sitting in the queue of zio's to be issued at
4270 * some point in the future. In this case, all we do is
4271 * remove the zio from the q_sios_by_addr tree, decrement
4272 * its data volume from the containing range_seg_t and
4273 * resort the q_exts_by_size tree to reflect that the
4274 * range_seg_t has lost some of its 'fill'. We don't shorten
4275 * the range_seg_t - this is usually rare enough not to be
4276 * worth the extra hassle of trying keep track of precise
4277 * extent boundaries.
4278 * 2) Hot, where the zio is currently in-flight in
4279 * dsl_scan_issue_ios. In this case, we can't simply
4280 * reach in and stop the in-flight zio's, so we instead
4281 * block the caller. Eventually, dsl_scan_issue_ios will
4282 * be done with issuing the zio's it gathered and will
4285 sio = avl_find(&queue->q_sios_by_addr, srch_sio, &idx);
4289 int64_t asize = SIO_GET_ASIZE(sio);
4292 /* Got it while it was cold in the queue */
4293 ASSERT3U(start, ==, SIO_GET_OFFSET(sio));
4294 ASSERT3U(size, ==, asize);
4295 avl_remove(&queue->q_sios_by_addr, sio);
4296 queue->q_sio_memused -= SIO_GET_MUSED(sio);
4298 ASSERT(range_tree_contains(queue->q_exts_by_addr, start, size));
4299 range_tree_remove_fill(queue->q_exts_by_addr, start, size);
4302 * We only update scn_bytes_pending in the cold path,
4303 * otherwise it will already have been accounted for as
4304 * part of the zio's execution.
4306 atomic_add_64(&scn->scn_bytes_pending, -asize);
4308 /* count the block as though we issued it */
4309 sio2bp(sio, &tmpbp);
4310 count_block(scn, dp->dp_blkstats, &tmpbp);
4318 * Callback invoked when a zio_free() zio is executing. This needs to be
4319 * intercepted to prevent the zio from deallocating a particular portion
4320 * of disk space and it then getting reallocated and written to, while we
4321 * still have it queued up for processing.
4324 dsl_scan_freed(spa_t *spa, const blkptr_t *bp)
4326 dsl_pool_t *dp = spa->spa_dsl_pool;
4327 dsl_scan_t *scn = dp->dp_scan;
4329 ASSERT(!BP_IS_EMBEDDED(bp));
4330 ASSERT(scn != NULL);
4331 if (!dsl_scan_is_running(scn))
4334 for (int i = 0; i < BP_GET_NDVAS(bp); i++)
4335 dsl_scan_freed_dva(spa, bp, i);
4339 * Check if a vdev needs resilvering (non-empty DTL), if so, and resilver has
4340 * not started, start it. Otherwise, only restart if max txg in DTL range is
4341 * greater than the max txg in the current scan. If the DTL max is less than
4342 * the scan max, then the vdev has not missed any new data since the resilver
4343 * started, so a restart is not needed.
4346 dsl_scan_assess_vdev(dsl_pool_t *dp, vdev_t *vd)
4350 if (!vdev_resilver_needed(vd, &min, &max))
4353 if (!dsl_scan_resilvering(dp)) {
4354 spa_async_request(dp->dp_spa, SPA_ASYNC_RESILVER);
4358 if (max <= dp->dp_scan->scn_phys.scn_max_txg)
4361 /* restart is needed, check if it can be deferred */
4362 if (spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_RESILVER_DEFER))
4363 vdev_defer_resilver(vd);
4365 spa_async_request(dp->dp_spa, SPA_ASYNC_RESILVER);
4369 ZFS_MODULE_PARAM(zfs, zfs_, scan_vdev_limit, ULONG, ZMOD_RW,
4370 "Max bytes in flight per leaf vdev for scrubs and resilvers");
4372 ZFS_MODULE_PARAM(zfs, zfs_, scrub_min_time_ms, INT, ZMOD_RW,
4373 "Min millisecs to scrub per txg");
4375 ZFS_MODULE_PARAM(zfs, zfs_, obsolete_min_time_ms, INT, ZMOD_RW,
4376 "Min millisecs to obsolete per txg");
4378 ZFS_MODULE_PARAM(zfs, zfs_, free_min_time_ms, INT, ZMOD_RW,
4379 "Min millisecs to free per txg");
4381 ZFS_MODULE_PARAM(zfs, zfs_, resilver_min_time_ms, INT, ZMOD_RW,
4382 "Min millisecs to resilver per txg");
4384 ZFS_MODULE_PARAM(zfs, zfs_, scan_suspend_progress, INT, ZMOD_RW,
4385 "Set to prevent scans from progressing");
4387 ZFS_MODULE_PARAM(zfs, zfs_, no_scrub_io, INT, ZMOD_RW,
4388 "Set to disable scrub I/O");
4390 ZFS_MODULE_PARAM(zfs, zfs_, no_scrub_prefetch, INT, ZMOD_RW,
4391 "Set to disable scrub prefetching");
4393 ZFS_MODULE_PARAM(zfs, zfs_, async_block_max_blocks, ULONG, ZMOD_RW,
4394 "Max number of blocks freed in one txg");
4396 ZFS_MODULE_PARAM(zfs, zfs_, max_async_dedup_frees, ULONG, ZMOD_RW,
4397 "Max number of dedup blocks freed in one txg");
4399 ZFS_MODULE_PARAM(zfs, zfs_, free_bpobj_enabled, INT, ZMOD_RW,
4400 "Enable processing of the free_bpobj");
4402 ZFS_MODULE_PARAM(zfs, zfs_, scan_mem_lim_fact, INT, ZMOD_RW,
4403 "Fraction of RAM for scan hard limit");
4405 ZFS_MODULE_PARAM(zfs, zfs_, scan_issue_strategy, INT, ZMOD_RW,
4406 "IO issuing strategy during scrubbing. "
4407 "0 = default, 1 = LBA, 2 = size");
4409 ZFS_MODULE_PARAM(zfs, zfs_, scan_legacy, INT, ZMOD_RW,
4410 "Scrub using legacy non-sequential method");
4412 ZFS_MODULE_PARAM(zfs, zfs_, scan_checkpoint_intval, INT, ZMOD_RW,
4413 "Scan progress on-disk checkpointing interval");
4415 ZFS_MODULE_PARAM(zfs, zfs_, scan_max_ext_gap, ULONG, ZMOD_RW,
4416 "Max gap in bytes between sequential scrub / resilver I/Os");
4418 ZFS_MODULE_PARAM(zfs, zfs_, scan_mem_lim_soft_fact, INT, ZMOD_RW,
4419 "Fraction of hard limit used as soft limit");
4421 ZFS_MODULE_PARAM(zfs, zfs_, scan_strict_mem_lim, INT, ZMOD_RW,
4422 "Tunable to attempt to reduce lock contention");
4424 ZFS_MODULE_PARAM(zfs, zfs_, scan_fill_weight, INT, ZMOD_RW,
4425 "Tunable to adjust bias towards more filled segments during scans");
4427 ZFS_MODULE_PARAM(zfs, zfs_, resilver_disable_defer, INT, ZMOD_RW,
4428 "Process all resilvers immediately");