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, 2021 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_data_disks(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_data_disks(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 for %s; "
471 "restarting new-style scrub in txg %llu",
473 (longlong_t)scn->scn_restart_txg);
476 * Load the queue obj from the old location so that it
477 * can be freed by dsl_scan_done().
479 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
480 "scrub_queue", sizeof (uint64_t), 1,
481 &scn->scn_phys.scn_queue_obj);
483 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
484 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
487 * Detect if the pool contains the signature of #2094. If it
488 * does properly update the scn->scn_phys structure and notify
489 * the administrator by setting an errata for the pool.
491 if (err == EOVERFLOW) {
492 uint64_t zaptmp[SCAN_PHYS_NUMINTS + 1];
493 VERIFY3S(SCAN_PHYS_NUMINTS, ==, 24);
494 VERIFY3S(offsetof(dsl_scan_phys_t, scn_flags), ==,
495 (23 * sizeof (uint64_t)));
497 err = zap_lookup(dp->dp_meta_objset,
498 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_SCAN,
499 sizeof (uint64_t), SCAN_PHYS_NUMINTS + 1, &zaptmp);
501 uint64_t overflow = zaptmp[SCAN_PHYS_NUMINTS];
503 if (overflow & ~DSL_SCAN_FLAGS_MASK ||
504 scn->scn_async_destroying) {
506 ZPOOL_ERRATA_ZOL_2094_ASYNC_DESTROY;
510 bcopy(zaptmp, &scn->scn_phys,
511 SCAN_PHYS_NUMINTS * sizeof (uint64_t));
512 scn->scn_phys.scn_flags = overflow;
514 /* Required scrub already in progress. */
515 if (scn->scn_phys.scn_state == DSS_FINISHED ||
516 scn->scn_phys.scn_state == DSS_CANCELED)
518 ZPOOL_ERRATA_ZOL_2094_SCRUB;
528 * We might be restarting after a reboot, so jump the issued
529 * counter to how far we've scanned. We know we're consistent
532 scn->scn_issued_before_pass = scn->scn_phys.scn_examined;
534 if (dsl_scan_is_running(scn) &&
535 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
537 * A new-type scrub was in progress on an old
538 * pool, and the pool was accessed by old
539 * software. Restart from the beginning, since
540 * the old software may have changed the pool in
543 scn->scn_restart_txg = txg;
544 zfs_dbgmsg("new-style scrub for %s was modified "
545 "by old software; restarting in txg %llu",
547 (longlong_t)scn->scn_restart_txg);
548 } else if (dsl_scan_resilvering(dp)) {
550 * If a resilver is in progress and there are already
551 * errors, restart it instead of finishing this scan and
552 * then restarting it. If there haven't been any errors
553 * then remember that the incore DTL is valid.
555 if (scn->scn_phys.scn_errors > 0) {
556 scn->scn_restart_txg = txg;
557 zfs_dbgmsg("resilver can't excise DTL_MISSING "
558 "when finished; restarting on %s in txg "
561 (u_longlong_t)scn->scn_restart_txg);
563 /* it's safe to excise DTL when finished */
564 spa->spa_scrub_started = B_TRUE;
569 bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
571 /* reload the queue into the in-core state */
572 if (scn->scn_phys.scn_queue_obj != 0) {
576 for (zap_cursor_init(&zc, dp->dp_meta_objset,
577 scn->scn_phys.scn_queue_obj);
578 zap_cursor_retrieve(&zc, &za) == 0;
579 (void) zap_cursor_advance(&zc)) {
580 scan_ds_queue_insert(scn,
581 zfs_strtonum(za.za_name, NULL),
582 za.za_first_integer);
584 zap_cursor_fini(&zc);
587 spa_scan_stat_init(spa);
592 dsl_scan_fini(dsl_pool_t *dp)
594 if (dp->dp_scan != NULL) {
595 dsl_scan_t *scn = dp->dp_scan;
597 if (scn->scn_taskq != NULL)
598 taskq_destroy(scn->scn_taskq);
600 scan_ds_queue_clear(scn);
601 avl_destroy(&scn->scn_queue);
602 scan_ds_prefetch_queue_clear(scn);
603 avl_destroy(&scn->scn_prefetch_queue);
605 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
611 dsl_scan_restarting(dsl_scan_t *scn, dmu_tx_t *tx)
613 return (scn->scn_restart_txg != 0 &&
614 scn->scn_restart_txg <= tx->tx_txg);
618 dsl_scan_resilver_scheduled(dsl_pool_t *dp)
620 return ((dp->dp_scan && dp->dp_scan->scn_restart_txg != 0) ||
621 (spa_async_tasks(dp->dp_spa) & SPA_ASYNC_RESILVER));
625 dsl_scan_scrubbing(const dsl_pool_t *dp)
627 dsl_scan_phys_t *scn_phys = &dp->dp_scan->scn_phys;
629 return (scn_phys->scn_state == DSS_SCANNING &&
630 scn_phys->scn_func == POOL_SCAN_SCRUB);
634 dsl_scan_is_paused_scrub(const dsl_scan_t *scn)
636 return (dsl_scan_scrubbing(scn->scn_dp) &&
637 scn->scn_phys.scn_flags & DSF_SCRUB_PAUSED);
641 * Writes out a persistent dsl_scan_phys_t record to the pool directory.
642 * Because we can be running in the block sorting algorithm, we do not always
643 * want to write out the record, only when it is "safe" to do so. This safety
644 * condition is achieved by making sure that the sorting queues are empty
645 * (scn_bytes_pending == 0). When this condition is not true, the sync'd state
646 * is inconsistent with how much actual scanning progress has been made. The
647 * kind of sync to be performed is specified by the sync_type argument. If the
648 * sync is optional, we only sync if the queues are empty. If the sync is
649 * mandatory, we do a hard ASSERT to make sure that the queues are empty. The
650 * third possible state is a "cached" sync. This is done in response to:
651 * 1) The dataset that was in the last sync'd dsl_scan_phys_t having been
652 * destroyed, so we wouldn't be able to restart scanning from it.
653 * 2) The snapshot that was in the last sync'd dsl_scan_phys_t having been
654 * superseded by a newer snapshot.
655 * 3) The dataset that was in the last sync'd dsl_scan_phys_t having been
656 * swapped with its clone.
657 * In all cases, a cached sync simply rewrites the last record we've written,
658 * just slightly modified. For the modifications that are performed to the
659 * last written dsl_scan_phys_t, see dsl_scan_ds_destroyed,
660 * dsl_scan_ds_snapshotted and dsl_scan_ds_clone_swapped.
663 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx, state_sync_type_t sync_type)
666 spa_t *spa = scn->scn_dp->dp_spa;
668 ASSERT(sync_type != SYNC_MANDATORY || scn->scn_bytes_pending == 0);
669 if (scn->scn_bytes_pending == 0) {
670 for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
671 vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
672 dsl_scan_io_queue_t *q = vd->vdev_scan_io_queue;
677 mutex_enter(&vd->vdev_scan_io_queue_lock);
678 ASSERT3P(avl_first(&q->q_sios_by_addr), ==, NULL);
679 ASSERT3P(zfs_btree_first(&q->q_exts_by_size, NULL), ==,
681 ASSERT3P(range_tree_first(q->q_exts_by_addr), ==, NULL);
682 mutex_exit(&vd->vdev_scan_io_queue_lock);
685 if (scn->scn_phys.scn_queue_obj != 0)
686 scan_ds_queue_sync(scn, tx);
687 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
688 DMU_POOL_DIRECTORY_OBJECT,
689 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
690 &scn->scn_phys, tx));
691 bcopy(&scn->scn_phys, &scn->scn_phys_cached,
692 sizeof (scn->scn_phys));
694 if (scn->scn_checkpointing)
695 zfs_dbgmsg("finish scan checkpoint for %s",
698 scn->scn_checkpointing = B_FALSE;
699 scn->scn_last_checkpoint = ddi_get_lbolt();
700 } else if (sync_type == SYNC_CACHED) {
701 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
702 DMU_POOL_DIRECTORY_OBJECT,
703 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
704 &scn->scn_phys_cached, tx));
710 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
712 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
713 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
715 if (dsl_scan_is_running(scn) || vdev_rebuild_active(rvd))
716 return (SET_ERROR(EBUSY));
722 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
724 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
725 pool_scan_func_t *funcp = arg;
726 dmu_object_type_t ot = 0;
727 dsl_pool_t *dp = scn->scn_dp;
728 spa_t *spa = dp->dp_spa;
730 ASSERT(!dsl_scan_is_running(scn));
731 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
732 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
733 scn->scn_phys.scn_func = *funcp;
734 scn->scn_phys.scn_state = DSS_SCANNING;
735 scn->scn_phys.scn_min_txg = 0;
736 scn->scn_phys.scn_max_txg = tx->tx_txg;
737 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
738 scn->scn_phys.scn_start_time = gethrestime_sec();
739 scn->scn_phys.scn_errors = 0;
740 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
741 scn->scn_issued_before_pass = 0;
742 scn->scn_restart_txg = 0;
743 scn->scn_done_txg = 0;
744 scn->scn_last_checkpoint = 0;
745 scn->scn_checkpointing = B_FALSE;
746 spa_scan_stat_init(spa);
748 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
749 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
751 /* rewrite all disk labels */
752 vdev_config_dirty(spa->spa_root_vdev);
754 if (vdev_resilver_needed(spa->spa_root_vdev,
755 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
756 nvlist_t *aux = fnvlist_alloc();
757 fnvlist_add_string(aux, ZFS_EV_RESILVER_TYPE,
759 spa_event_notify(spa, NULL, aux,
760 ESC_ZFS_RESILVER_START);
763 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_START);
766 spa->spa_scrub_started = B_TRUE;
768 * If this is an incremental scrub, limit the DDT scrub phase
769 * to just the auto-ditto class (for correctness); the rest
770 * of the scrub should go faster using top-down pruning.
772 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
773 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
776 * When starting a resilver clear any existing rebuild state.
777 * This is required to prevent stale rebuild status from
778 * being reported when a rebuild is run, then a resilver and
779 * finally a scrub. In which case only the scrub status
780 * should be reported by 'zpool status'.
782 if (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) {
783 vdev_t *rvd = spa->spa_root_vdev;
784 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
785 vdev_t *vd = rvd->vdev_child[i];
786 vdev_rebuild_clear_sync(
787 (void *)(uintptr_t)vd->vdev_id, tx);
792 /* back to the generic stuff */
794 if (dp->dp_blkstats == NULL) {
796 vmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
797 mutex_init(&dp->dp_blkstats->zab_lock, NULL,
798 MUTEX_DEFAULT, NULL);
800 bzero(&dp->dp_blkstats->zab_type, sizeof (dp->dp_blkstats->zab_type));
802 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
803 ot = DMU_OT_ZAP_OTHER;
805 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
806 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
808 bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
810 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
812 spa_history_log_internal(spa, "scan setup", tx,
813 "func=%u mintxg=%llu maxtxg=%llu",
814 *funcp, (u_longlong_t)scn->scn_phys.scn_min_txg,
815 (u_longlong_t)scn->scn_phys.scn_max_txg);
819 * Called by the ZFS_IOC_POOL_SCAN ioctl to start a scrub or resilver.
820 * Can also be called to resume a paused scrub.
823 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
825 spa_t *spa = dp->dp_spa;
826 dsl_scan_t *scn = dp->dp_scan;
829 * Purge all vdev caches and probe all devices. We do this here
830 * rather than in sync context because this requires a writer lock
831 * on the spa_config lock, which we can't do from sync context. The
832 * spa_scrub_reopen flag indicates that vdev_open() should not
833 * attempt to start another scrub.
835 spa_vdev_state_enter(spa, SCL_NONE);
836 spa->spa_scrub_reopen = B_TRUE;
837 vdev_reopen(spa->spa_root_vdev);
838 spa->spa_scrub_reopen = B_FALSE;
839 (void) spa_vdev_state_exit(spa, NULL, 0);
841 if (func == POOL_SCAN_RESILVER) {
842 dsl_scan_restart_resilver(spa->spa_dsl_pool, 0);
846 if (func == POOL_SCAN_SCRUB && dsl_scan_is_paused_scrub(scn)) {
847 /* got scrub start cmd, resume paused scrub */
848 int err = dsl_scrub_set_pause_resume(scn->scn_dp,
851 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_RESUME);
852 return (SET_ERROR(ECANCELED));
855 return (SET_ERROR(err));
858 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
859 dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_EXTRA_RESERVED));
864 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
866 static const char *old_names[] = {
868 "scrub_ddt_bookmark",
869 "scrub_ddt_class_max",
878 dsl_pool_t *dp = scn->scn_dp;
879 spa_t *spa = dp->dp_spa;
882 /* Remove any remnants of an old-style scrub. */
883 for (i = 0; old_names[i]; i++) {
884 (void) zap_remove(dp->dp_meta_objset,
885 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
888 if (scn->scn_phys.scn_queue_obj != 0) {
889 VERIFY0(dmu_object_free(dp->dp_meta_objset,
890 scn->scn_phys.scn_queue_obj, tx));
891 scn->scn_phys.scn_queue_obj = 0;
893 scan_ds_queue_clear(scn);
894 scan_ds_prefetch_queue_clear(scn);
896 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
899 * If we were "restarted" from a stopped state, don't bother
900 * with anything else.
902 if (!dsl_scan_is_running(scn)) {
903 ASSERT(!scn->scn_is_sorted);
907 if (scn->scn_is_sorted) {
908 scan_io_queues_destroy(scn);
909 scn->scn_is_sorted = B_FALSE;
911 if (scn->scn_taskq != NULL) {
912 taskq_destroy(scn->scn_taskq);
913 scn->scn_taskq = NULL;
917 scn->scn_phys.scn_state = complete ? DSS_FINISHED : DSS_CANCELED;
919 spa_notify_waiters(spa);
921 if (dsl_scan_restarting(scn, tx))
922 spa_history_log_internal(spa, "scan aborted, restarting", tx,
923 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa));
925 spa_history_log_internal(spa, "scan cancelled", tx,
926 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa));
928 spa_history_log_internal(spa, "scan done", tx,
929 "errors=%llu", (u_longlong_t)spa_get_errlog_size(spa));
931 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
932 spa->spa_scrub_active = B_FALSE;
935 * If the scrub/resilver completed, update all DTLs to
936 * reflect this. Whether it succeeded or not, vacate
937 * all temporary scrub DTLs.
939 * As the scrub does not currently support traversing
940 * data that have been freed but are part of a checkpoint,
941 * we don't mark the scrub as done in the DTLs as faults
942 * may still exist in those vdevs.
945 !spa_feature_is_active(spa, SPA_FEATURE_POOL_CHECKPOINT)) {
946 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
947 scn->scn_phys.scn_max_txg, B_TRUE, B_FALSE);
949 if (scn->scn_phys.scn_min_txg) {
950 nvlist_t *aux = fnvlist_alloc();
951 fnvlist_add_string(aux, ZFS_EV_RESILVER_TYPE,
953 spa_event_notify(spa, NULL, aux,
954 ESC_ZFS_RESILVER_FINISH);
957 spa_event_notify(spa, NULL, NULL,
958 ESC_ZFS_SCRUB_FINISH);
961 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
964 spa_errlog_rotate(spa);
967 * Don't clear flag until after vdev_dtl_reassess to ensure that
968 * DTL_MISSING will get updated when possible.
970 spa->spa_scrub_started = B_FALSE;
973 * We may have finished replacing a device.
974 * Let the async thread assess this and handle the detach.
976 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
979 * Clear any resilver_deferred flags in the config.
980 * If there are drives that need resilvering, kick
981 * off an asynchronous request to start resilver.
982 * vdev_clear_resilver_deferred() may update the config
983 * before the resilver can restart. In the event of
984 * a crash during this period, the spa loading code
985 * will find the drives that need to be resilvered
986 * and start the resilver then.
988 if (spa_feature_is_enabled(spa, SPA_FEATURE_RESILVER_DEFER) &&
989 vdev_clear_resilver_deferred(spa->spa_root_vdev, tx)) {
990 spa_history_log_internal(spa,
991 "starting deferred resilver", tx, "errors=%llu",
992 (u_longlong_t)spa_get_errlog_size(spa));
993 spa_async_request(spa, SPA_ASYNC_RESILVER);
996 /* Clear recent error events (i.e. duplicate events tracking) */
998 zfs_ereport_clear(spa, NULL);
1001 scn->scn_phys.scn_end_time = gethrestime_sec();
1003 if (spa->spa_errata == ZPOOL_ERRATA_ZOL_2094_SCRUB)
1004 spa->spa_errata = 0;
1006 ASSERT(!dsl_scan_is_running(scn));
1011 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
1013 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
1015 if (!dsl_scan_is_running(scn))
1016 return (SET_ERROR(ENOENT));
1022 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
1024 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
1026 dsl_scan_done(scn, B_FALSE, tx);
1027 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
1028 spa_event_notify(scn->scn_dp->dp_spa, NULL, NULL, ESC_ZFS_SCRUB_ABORT);
1032 dsl_scan_cancel(dsl_pool_t *dp)
1034 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
1035 dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED));
1039 dsl_scrub_pause_resume_check(void *arg, dmu_tx_t *tx)
1041 pool_scrub_cmd_t *cmd = arg;
1042 dsl_pool_t *dp = dmu_tx_pool(tx);
1043 dsl_scan_t *scn = dp->dp_scan;
1045 if (*cmd == POOL_SCRUB_PAUSE) {
1046 /* can't pause a scrub when there is no in-progress scrub */
1047 if (!dsl_scan_scrubbing(dp))
1048 return (SET_ERROR(ENOENT));
1050 /* can't pause a paused scrub */
1051 if (dsl_scan_is_paused_scrub(scn))
1052 return (SET_ERROR(EBUSY));
1053 } else if (*cmd != POOL_SCRUB_NORMAL) {
1054 return (SET_ERROR(ENOTSUP));
1061 dsl_scrub_pause_resume_sync(void *arg, dmu_tx_t *tx)
1063 pool_scrub_cmd_t *cmd = arg;
1064 dsl_pool_t *dp = dmu_tx_pool(tx);
1065 spa_t *spa = dp->dp_spa;
1066 dsl_scan_t *scn = dp->dp_scan;
1068 if (*cmd == POOL_SCRUB_PAUSE) {
1069 /* can't pause a scrub when there is no in-progress scrub */
1070 spa->spa_scan_pass_scrub_pause = gethrestime_sec();
1071 scn->scn_phys.scn_flags |= DSF_SCRUB_PAUSED;
1072 scn->scn_phys_cached.scn_flags |= DSF_SCRUB_PAUSED;
1073 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
1074 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_PAUSED);
1075 spa_notify_waiters(spa);
1077 ASSERT3U(*cmd, ==, POOL_SCRUB_NORMAL);
1078 if (dsl_scan_is_paused_scrub(scn)) {
1080 * We need to keep track of how much time we spend
1081 * paused per pass so that we can adjust the scrub rate
1082 * shown in the output of 'zpool status'
1084 spa->spa_scan_pass_scrub_spent_paused +=
1085 gethrestime_sec() - spa->spa_scan_pass_scrub_pause;
1086 spa->spa_scan_pass_scrub_pause = 0;
1087 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
1088 scn->scn_phys_cached.scn_flags &= ~DSF_SCRUB_PAUSED;
1089 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
1095 * Set scrub pause/resume state if it makes sense to do so
1098 dsl_scrub_set_pause_resume(const dsl_pool_t *dp, pool_scrub_cmd_t cmd)
1100 return (dsl_sync_task(spa_name(dp->dp_spa),
1101 dsl_scrub_pause_resume_check, dsl_scrub_pause_resume_sync, &cmd, 3,
1102 ZFS_SPACE_CHECK_RESERVED));
1106 /* start a new scan, or restart an existing one. */
1108 dsl_scan_restart_resilver(dsl_pool_t *dp, uint64_t txg)
1112 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1113 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1115 txg = dmu_tx_get_txg(tx);
1116 dp->dp_scan->scn_restart_txg = txg;
1119 dp->dp_scan->scn_restart_txg = txg;
1121 zfs_dbgmsg("restarting resilver for %s at txg=%llu",
1122 dp->dp_spa->spa_name, (longlong_t)txg);
1126 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
1128 zio_free(dp->dp_spa, txg, bp);
1132 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
1134 ASSERT(dsl_pool_sync_context(dp));
1135 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
1139 scan_ds_queue_compare(const void *a, const void *b)
1141 const scan_ds_t *sds_a = a, *sds_b = b;
1143 if (sds_a->sds_dsobj < sds_b->sds_dsobj)
1145 if (sds_a->sds_dsobj == sds_b->sds_dsobj)
1151 scan_ds_queue_clear(dsl_scan_t *scn)
1153 void *cookie = NULL;
1155 while ((sds = avl_destroy_nodes(&scn->scn_queue, &cookie)) != NULL) {
1156 kmem_free(sds, sizeof (*sds));
1161 scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj, uint64_t *txg)
1163 scan_ds_t srch, *sds;
1165 srch.sds_dsobj = dsobj;
1166 sds = avl_find(&scn->scn_queue, &srch, NULL);
1167 if (sds != NULL && txg != NULL)
1168 *txg = sds->sds_txg;
1169 return (sds != NULL);
1173 scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg)
1178 sds = kmem_zalloc(sizeof (*sds), KM_SLEEP);
1179 sds->sds_dsobj = dsobj;
1182 VERIFY3P(avl_find(&scn->scn_queue, sds, &where), ==, NULL);
1183 avl_insert(&scn->scn_queue, sds, where);
1187 scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj)
1189 scan_ds_t srch, *sds;
1191 srch.sds_dsobj = dsobj;
1193 sds = avl_find(&scn->scn_queue, &srch, NULL);
1194 VERIFY(sds != NULL);
1195 avl_remove(&scn->scn_queue, sds);
1196 kmem_free(sds, sizeof (*sds));
1200 scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx)
1202 dsl_pool_t *dp = scn->scn_dp;
1203 spa_t *spa = dp->dp_spa;
1204 dmu_object_type_t ot = (spa_version(spa) >= SPA_VERSION_DSL_SCRUB) ?
1205 DMU_OT_SCAN_QUEUE : DMU_OT_ZAP_OTHER;
1207 ASSERT0(scn->scn_bytes_pending);
1208 ASSERT(scn->scn_phys.scn_queue_obj != 0);
1210 VERIFY0(dmu_object_free(dp->dp_meta_objset,
1211 scn->scn_phys.scn_queue_obj, tx));
1212 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset, ot,
1213 DMU_OT_NONE, 0, tx);
1214 for (scan_ds_t *sds = avl_first(&scn->scn_queue);
1215 sds != NULL; sds = AVL_NEXT(&scn->scn_queue, sds)) {
1216 VERIFY0(zap_add_int_key(dp->dp_meta_objset,
1217 scn->scn_phys.scn_queue_obj, sds->sds_dsobj,
1223 * Computes the memory limit state that we're currently in. A sorted scan
1224 * needs quite a bit of memory to hold the sorting queue, so we need to
1225 * reasonably constrain the size so it doesn't impact overall system
1226 * performance. We compute two limits:
1227 * 1) Hard memory limit: if the amount of memory used by the sorting
1228 * queues on a pool gets above this value, we stop the metadata
1229 * scanning portion and start issuing the queued up and sorted
1230 * I/Os to reduce memory usage.
1231 * This limit is calculated as a fraction of physmem (by default 5%).
1232 * We constrain the lower bound of the hard limit to an absolute
1233 * minimum of zfs_scan_mem_lim_min (default: 16 MiB). We also constrain
1234 * the upper bound to 5% of the total pool size - no chance we'll
1235 * ever need that much memory, but just to keep the value in check.
1236 * 2) Soft memory limit: once we hit the hard memory limit, we start
1237 * issuing I/O to reduce queue memory usage, but we don't want to
1238 * completely empty out the queues, since we might be able to find I/Os
1239 * that will fill in the gaps of our non-sequential IOs at some point
1240 * in the future. So we stop the issuing of I/Os once the amount of
1241 * memory used drops below the soft limit (at which point we stop issuing
1242 * I/O and start scanning metadata again).
1244 * This limit is calculated by subtracting a fraction of the hard
1245 * limit from the hard limit. By default this fraction is 5%, so
1246 * the soft limit is 95% of the hard limit. We cap the size of the
1247 * difference between the hard and soft limits at an absolute
1248 * maximum of zfs_scan_mem_lim_soft_max (default: 128 MiB) - this is
1249 * sufficient to not cause too frequent switching between the
1250 * metadata scan and I/O issue (even at 2k recordsize, 128 MiB's
1251 * worth of queues is about 1.2 GiB of on-pool data, so scanning
1252 * that should take at least a decent fraction of a second).
1255 dsl_scan_should_clear(dsl_scan_t *scn)
1257 spa_t *spa = scn->scn_dp->dp_spa;
1258 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
1259 uint64_t alloc, mlim_hard, mlim_soft, mused;
1261 alloc = metaslab_class_get_alloc(spa_normal_class(spa));
1262 alloc += metaslab_class_get_alloc(spa_special_class(spa));
1263 alloc += metaslab_class_get_alloc(spa_dedup_class(spa));
1265 mlim_hard = MAX((physmem / zfs_scan_mem_lim_fact) * PAGESIZE,
1266 zfs_scan_mem_lim_min);
1267 mlim_hard = MIN(mlim_hard, alloc / 20);
1268 mlim_soft = mlim_hard - MIN(mlim_hard / zfs_scan_mem_lim_soft_fact,
1269 zfs_scan_mem_lim_soft_max);
1271 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
1272 vdev_t *tvd = rvd->vdev_child[i];
1273 dsl_scan_io_queue_t *queue;
1275 mutex_enter(&tvd->vdev_scan_io_queue_lock);
1276 queue = tvd->vdev_scan_io_queue;
1277 if (queue != NULL) {
1278 /* # extents in exts_by_size = # in exts_by_addr */
1279 mused += zfs_btree_numnodes(&queue->q_exts_by_size) *
1280 sizeof (range_seg_gap_t) + queue->q_sio_memused;
1282 mutex_exit(&tvd->vdev_scan_io_queue_lock);
1285 dprintf("current scan memory usage: %llu bytes\n", (longlong_t)mused);
1288 ASSERT0(scn->scn_bytes_pending);
1291 * If we are above our hard limit, we need to clear out memory.
1292 * If we are below our soft limit, we need to accumulate sequential IOs.
1293 * Otherwise, we should keep doing whatever we are currently doing.
1295 if (mused >= mlim_hard)
1297 else if (mused < mlim_soft)
1300 return (scn->scn_clearing);
1304 dsl_scan_check_suspend(dsl_scan_t *scn, const zbookmark_phys_t *zb)
1306 /* we never skip user/group accounting objects */
1307 if (zb && (int64_t)zb->zb_object < 0)
1310 if (scn->scn_suspending)
1311 return (B_TRUE); /* we're already suspending */
1313 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
1314 return (B_FALSE); /* we're resuming */
1316 /* We only know how to resume from level-0 and objset blocks. */
1317 if (zb && (zb->zb_level != 0 && zb->zb_level != ZB_ROOT_LEVEL))
1322 * - we have scanned for at least the minimum time (default 1 sec
1323 * for scrub, 3 sec for resilver), and either we have sufficient
1324 * dirty data that we are starting to write more quickly
1325 * (default 30%), someone is explicitly waiting for this txg
1326 * to complete, or we have used up all of the time in the txg
1327 * timeout (default 5 sec).
1329 * - the spa is shutting down because this pool is being exported
1330 * or the machine is rebooting.
1332 * - the scan queue has reached its memory use limit
1334 uint64_t curr_time_ns = gethrtime();
1335 uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time;
1336 uint64_t sync_time_ns = curr_time_ns -
1337 scn->scn_dp->dp_spa->spa_sync_starttime;
1338 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
1339 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
1340 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
1342 if ((NSEC2MSEC(scan_time_ns) > mintime &&
1343 (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent ||
1344 txg_sync_waiting(scn->scn_dp) ||
1345 NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) ||
1346 spa_shutting_down(scn->scn_dp->dp_spa) ||
1347 (zfs_scan_strict_mem_lim && dsl_scan_should_clear(scn))) {
1348 if (zb && zb->zb_level == ZB_ROOT_LEVEL) {
1349 dprintf("suspending at first available bookmark "
1350 "%llx/%llx/%llx/%llx\n",
1351 (longlong_t)zb->zb_objset,
1352 (longlong_t)zb->zb_object,
1353 (longlong_t)zb->zb_level,
1354 (longlong_t)zb->zb_blkid);
1355 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
1356 zb->zb_objset, 0, 0, 0);
1357 } else if (zb != NULL) {
1358 dprintf("suspending at bookmark %llx/%llx/%llx/%llx\n",
1359 (longlong_t)zb->zb_objset,
1360 (longlong_t)zb->zb_object,
1361 (longlong_t)zb->zb_level,
1362 (longlong_t)zb->zb_blkid);
1363 scn->scn_phys.scn_bookmark = *zb;
1366 dsl_scan_phys_t *scnp = &scn->scn_phys;
1367 dprintf("suspending at at DDT bookmark "
1368 "%llx/%llx/%llx/%llx\n",
1369 (longlong_t)scnp->scn_ddt_bookmark.ddb_class,
1370 (longlong_t)scnp->scn_ddt_bookmark.ddb_type,
1371 (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum,
1372 (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor);
1375 scn->scn_suspending = B_TRUE;
1381 typedef struct zil_scan_arg {
1383 zil_header_t *zsa_zh;
1388 dsl_scan_zil_block(zilog_t *zilog, const blkptr_t *bp, void *arg,
1391 zil_scan_arg_t *zsa = arg;
1392 dsl_pool_t *dp = zsa->zsa_dp;
1393 dsl_scan_t *scn = dp->dp_scan;
1394 zil_header_t *zh = zsa->zsa_zh;
1395 zbookmark_phys_t zb;
1397 ASSERT(!BP_IS_REDACTED(bp));
1398 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
1402 * One block ("stubby") can be allocated a long time ago; we
1403 * want to visit that one because it has been allocated
1404 * (on-disk) even if it hasn't been claimed (even though for
1405 * scrub there's nothing to do to it).
1407 if (claim_txg == 0 && bp->blk_birth >= spa_min_claim_txg(dp->dp_spa))
1410 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
1411 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
1413 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
1419 dsl_scan_zil_record(zilog_t *zilog, const lr_t *lrc, void *arg,
1422 if (lrc->lrc_txtype == TX_WRITE) {
1423 zil_scan_arg_t *zsa = arg;
1424 dsl_pool_t *dp = zsa->zsa_dp;
1425 dsl_scan_t *scn = dp->dp_scan;
1426 zil_header_t *zh = zsa->zsa_zh;
1427 const lr_write_t *lr = (const lr_write_t *)lrc;
1428 const blkptr_t *bp = &lr->lr_blkptr;
1429 zbookmark_phys_t zb;
1431 ASSERT(!BP_IS_REDACTED(bp));
1432 if (BP_IS_HOLE(bp) ||
1433 bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
1437 * birth can be < claim_txg if this record's txg is
1438 * already txg sync'ed (but this log block contains
1439 * other records that are not synced)
1441 if (claim_txg == 0 || bp->blk_birth < claim_txg)
1444 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
1445 lr->lr_foid, ZB_ZIL_LEVEL,
1446 lr->lr_offset / BP_GET_LSIZE(bp));
1448 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
1454 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
1456 uint64_t claim_txg = zh->zh_claim_txg;
1457 zil_scan_arg_t zsa = { dp, zh };
1460 ASSERT(spa_writeable(dp->dp_spa));
1463 * We only want to visit blocks that have been claimed but not yet
1464 * replayed (or, in read-only mode, blocks that *would* be claimed).
1469 zilog = zil_alloc(dp->dp_meta_objset, zh);
1471 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
1472 claim_txg, B_FALSE);
1478 * We compare scan_prefetch_issue_ctx_t's based on their bookmarks. The idea
1479 * here is to sort the AVL tree by the order each block will be needed.
1482 scan_prefetch_queue_compare(const void *a, const void *b)
1484 const scan_prefetch_issue_ctx_t *spic_a = a, *spic_b = b;
1485 const scan_prefetch_ctx_t *spc_a = spic_a->spic_spc;
1486 const scan_prefetch_ctx_t *spc_b = spic_b->spic_spc;
1488 return (zbookmark_compare(spc_a->spc_datablkszsec,
1489 spc_a->spc_indblkshift, spc_b->spc_datablkszsec,
1490 spc_b->spc_indblkshift, &spic_a->spic_zb, &spic_b->spic_zb));
1494 scan_prefetch_ctx_rele(scan_prefetch_ctx_t *spc, void *tag)
1496 if (zfs_refcount_remove(&spc->spc_refcnt, tag) == 0) {
1497 zfs_refcount_destroy(&spc->spc_refcnt);
1498 kmem_free(spc, sizeof (scan_prefetch_ctx_t));
1502 static scan_prefetch_ctx_t *
1503 scan_prefetch_ctx_create(dsl_scan_t *scn, dnode_phys_t *dnp, void *tag)
1505 scan_prefetch_ctx_t *spc;
1507 spc = kmem_alloc(sizeof (scan_prefetch_ctx_t), KM_SLEEP);
1508 zfs_refcount_create(&spc->spc_refcnt);
1509 zfs_refcount_add(&spc->spc_refcnt, tag);
1512 spc->spc_datablkszsec = dnp->dn_datablkszsec;
1513 spc->spc_indblkshift = dnp->dn_indblkshift;
1514 spc->spc_root = B_FALSE;
1516 spc->spc_datablkszsec = 0;
1517 spc->spc_indblkshift = 0;
1518 spc->spc_root = B_TRUE;
1525 scan_prefetch_ctx_add_ref(scan_prefetch_ctx_t *spc, void *tag)
1527 zfs_refcount_add(&spc->spc_refcnt, tag);
1531 scan_ds_prefetch_queue_clear(dsl_scan_t *scn)
1533 spa_t *spa = scn->scn_dp->dp_spa;
1534 void *cookie = NULL;
1535 scan_prefetch_issue_ctx_t *spic = NULL;
1537 mutex_enter(&spa->spa_scrub_lock);
1538 while ((spic = avl_destroy_nodes(&scn->scn_prefetch_queue,
1539 &cookie)) != NULL) {
1540 scan_prefetch_ctx_rele(spic->spic_spc, scn);
1541 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1543 mutex_exit(&spa->spa_scrub_lock);
1547 dsl_scan_check_prefetch_resume(scan_prefetch_ctx_t *spc,
1548 const zbookmark_phys_t *zb)
1550 zbookmark_phys_t *last_zb = &spc->spc_scn->scn_prefetch_bookmark;
1551 dnode_phys_t tmp_dnp;
1552 dnode_phys_t *dnp = (spc->spc_root) ? NULL : &tmp_dnp;
1554 if (zb->zb_objset != last_zb->zb_objset)
1556 if ((int64_t)zb->zb_object < 0)
1559 tmp_dnp.dn_datablkszsec = spc->spc_datablkszsec;
1560 tmp_dnp.dn_indblkshift = spc->spc_indblkshift;
1562 if (zbookmark_subtree_completed(dnp, zb, last_zb))
1569 dsl_scan_prefetch(scan_prefetch_ctx_t *spc, blkptr_t *bp, zbookmark_phys_t *zb)
1572 dsl_scan_t *scn = spc->spc_scn;
1573 spa_t *spa = scn->scn_dp->dp_spa;
1574 scan_prefetch_issue_ctx_t *spic;
1576 if (zfs_no_scrub_prefetch || BP_IS_REDACTED(bp))
1579 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg ||
1580 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE &&
1581 BP_GET_TYPE(bp) != DMU_OT_OBJSET))
1584 if (dsl_scan_check_prefetch_resume(spc, zb))
1587 scan_prefetch_ctx_add_ref(spc, scn);
1588 spic = kmem_alloc(sizeof (scan_prefetch_issue_ctx_t), KM_SLEEP);
1589 spic->spic_spc = spc;
1590 spic->spic_bp = *bp;
1591 spic->spic_zb = *zb;
1594 * Add the IO to the queue of blocks to prefetch. This allows us to
1595 * prioritize blocks that we will need first for the main traversal
1598 mutex_enter(&spa->spa_scrub_lock);
1599 if (avl_find(&scn->scn_prefetch_queue, spic, &idx) != NULL) {
1600 /* this block is already queued for prefetch */
1601 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1602 scan_prefetch_ctx_rele(spc, scn);
1603 mutex_exit(&spa->spa_scrub_lock);
1607 avl_insert(&scn->scn_prefetch_queue, spic, idx);
1608 cv_broadcast(&spa->spa_scrub_io_cv);
1609 mutex_exit(&spa->spa_scrub_lock);
1613 dsl_scan_prefetch_dnode(dsl_scan_t *scn, dnode_phys_t *dnp,
1614 uint64_t objset, uint64_t object)
1617 zbookmark_phys_t zb;
1618 scan_prefetch_ctx_t *spc;
1620 if (dnp->dn_nblkptr == 0 && !(dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR))
1623 SET_BOOKMARK(&zb, objset, object, 0, 0);
1625 spc = scan_prefetch_ctx_create(scn, dnp, FTAG);
1627 for (i = 0; i < dnp->dn_nblkptr; i++) {
1628 zb.zb_level = BP_GET_LEVEL(&dnp->dn_blkptr[i]);
1630 dsl_scan_prefetch(spc, &dnp->dn_blkptr[i], &zb);
1633 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
1635 zb.zb_blkid = DMU_SPILL_BLKID;
1636 dsl_scan_prefetch(spc, DN_SPILL_BLKPTR(dnp), &zb);
1639 scan_prefetch_ctx_rele(spc, FTAG);
1643 dsl_scan_prefetch_cb(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp,
1644 arc_buf_t *buf, void *private)
1646 scan_prefetch_ctx_t *spc = private;
1647 dsl_scan_t *scn = spc->spc_scn;
1648 spa_t *spa = scn->scn_dp->dp_spa;
1650 /* broadcast that the IO has completed for rate limiting purposes */
1651 mutex_enter(&spa->spa_scrub_lock);
1652 ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp));
1653 spa->spa_scrub_inflight -= BP_GET_PSIZE(bp);
1654 cv_broadcast(&spa->spa_scrub_io_cv);
1655 mutex_exit(&spa->spa_scrub_lock);
1657 /* if there was an error or we are done prefetching, just cleanup */
1658 if (buf == NULL || scn->scn_prefetch_stop)
1661 if (BP_GET_LEVEL(bp) > 0) {
1664 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
1665 zbookmark_phys_t czb;
1667 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
1668 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
1669 zb->zb_level - 1, zb->zb_blkid * epb + i);
1670 dsl_scan_prefetch(spc, cbp, &czb);
1672 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
1675 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
1677 for (i = 0, cdnp = buf->b_data; i < epb;
1678 i += cdnp->dn_extra_slots + 1,
1679 cdnp += cdnp->dn_extra_slots + 1) {
1680 dsl_scan_prefetch_dnode(scn, cdnp,
1681 zb->zb_objset, zb->zb_blkid * epb + i);
1683 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
1684 objset_phys_t *osp = buf->b_data;
1686 dsl_scan_prefetch_dnode(scn, &osp->os_meta_dnode,
1687 zb->zb_objset, DMU_META_DNODE_OBJECT);
1689 if (OBJSET_BUF_HAS_USERUSED(buf)) {
1690 dsl_scan_prefetch_dnode(scn,
1691 &osp->os_groupused_dnode, zb->zb_objset,
1692 DMU_GROUPUSED_OBJECT);
1693 dsl_scan_prefetch_dnode(scn,
1694 &osp->os_userused_dnode, zb->zb_objset,
1695 DMU_USERUSED_OBJECT);
1701 arc_buf_destroy(buf, private);
1702 scan_prefetch_ctx_rele(spc, scn);
1707 dsl_scan_prefetch_thread(void *arg)
1709 dsl_scan_t *scn = arg;
1710 spa_t *spa = scn->scn_dp->dp_spa;
1711 scan_prefetch_issue_ctx_t *spic;
1713 /* loop until we are told to stop */
1714 while (!scn->scn_prefetch_stop) {
1715 arc_flags_t flags = ARC_FLAG_NOWAIT |
1716 ARC_FLAG_PRESCIENT_PREFETCH | ARC_FLAG_PREFETCH;
1717 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
1719 mutex_enter(&spa->spa_scrub_lock);
1722 * Wait until we have an IO to issue and are not above our
1723 * maximum in flight limit.
1725 while (!scn->scn_prefetch_stop &&
1726 (avl_numnodes(&scn->scn_prefetch_queue) == 0 ||
1727 spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes)) {
1728 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1731 /* recheck if we should stop since we waited for the cv */
1732 if (scn->scn_prefetch_stop) {
1733 mutex_exit(&spa->spa_scrub_lock);
1737 /* remove the prefetch IO from the tree */
1738 spic = avl_first(&scn->scn_prefetch_queue);
1739 spa->spa_scrub_inflight += BP_GET_PSIZE(&spic->spic_bp);
1740 avl_remove(&scn->scn_prefetch_queue, spic);
1742 mutex_exit(&spa->spa_scrub_lock);
1744 if (BP_IS_PROTECTED(&spic->spic_bp)) {
1745 ASSERT(BP_GET_TYPE(&spic->spic_bp) == DMU_OT_DNODE ||
1746 BP_GET_TYPE(&spic->spic_bp) == DMU_OT_OBJSET);
1747 ASSERT3U(BP_GET_LEVEL(&spic->spic_bp), ==, 0);
1748 zio_flags |= ZIO_FLAG_RAW;
1751 /* issue the prefetch asynchronously */
1752 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa,
1753 &spic->spic_bp, dsl_scan_prefetch_cb, spic->spic_spc,
1754 ZIO_PRIORITY_SCRUB, zio_flags, &flags, &spic->spic_zb);
1756 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1759 ASSERT(scn->scn_prefetch_stop);
1761 /* free any prefetches we didn't get to complete */
1762 mutex_enter(&spa->spa_scrub_lock);
1763 while ((spic = avl_first(&scn->scn_prefetch_queue)) != NULL) {
1764 avl_remove(&scn->scn_prefetch_queue, spic);
1765 scan_prefetch_ctx_rele(spic->spic_spc, scn);
1766 kmem_free(spic, sizeof (scan_prefetch_issue_ctx_t));
1768 ASSERT0(avl_numnodes(&scn->scn_prefetch_queue));
1769 mutex_exit(&spa->spa_scrub_lock);
1773 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
1774 const zbookmark_phys_t *zb)
1777 * We never skip over user/group accounting objects (obj<0)
1779 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
1780 (int64_t)zb->zb_object >= 0) {
1782 * If we already visited this bp & everything below (in
1783 * a prior txg sync), don't bother doing it again.
1785 if (zbookmark_subtree_completed(dnp, zb,
1786 &scn->scn_phys.scn_bookmark))
1790 * If we found the block we're trying to resume from, or
1791 * we went past it to a different object, zero it out to
1792 * indicate that it's OK to start checking for suspending
1795 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
1796 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
1797 dprintf("resuming at %llx/%llx/%llx/%llx\n",
1798 (longlong_t)zb->zb_objset,
1799 (longlong_t)zb->zb_object,
1800 (longlong_t)zb->zb_level,
1801 (longlong_t)zb->zb_blkid);
1802 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
1808 static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
1809 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
1810 dmu_objset_type_t ostype, dmu_tx_t *tx);
1811 inline __attribute__((always_inline)) static void dsl_scan_visitdnode(
1812 dsl_scan_t *, dsl_dataset_t *ds, dmu_objset_type_t ostype,
1813 dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
1816 * Return nonzero on i/o error.
1817 * Return new buf to write out in *bufp.
1819 inline __attribute__((always_inline)) static int
1820 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
1821 dnode_phys_t *dnp, const blkptr_t *bp,
1822 const zbookmark_phys_t *zb, dmu_tx_t *tx)
1824 dsl_pool_t *dp = scn->scn_dp;
1825 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
1828 ASSERT(!BP_IS_REDACTED(bp));
1830 if (BP_GET_LEVEL(bp) > 0) {
1831 arc_flags_t flags = ARC_FLAG_WAIT;
1834 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
1837 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1838 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb);
1840 scn->scn_phys.scn_errors++;
1843 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
1844 zbookmark_phys_t czb;
1846 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
1848 zb->zb_blkid * epb + i);
1849 dsl_scan_visitbp(cbp, &czb, dnp,
1850 ds, scn, ostype, tx);
1852 arc_buf_destroy(buf, &buf);
1853 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
1854 arc_flags_t flags = ARC_FLAG_WAIT;
1857 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
1860 if (BP_IS_PROTECTED(bp)) {
1861 ASSERT3U(BP_GET_COMPRESS(bp), ==, ZIO_COMPRESS_OFF);
1862 zio_flags |= ZIO_FLAG_RAW;
1865 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1866 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb);
1868 scn->scn_phys.scn_errors++;
1871 for (i = 0, cdnp = buf->b_data; i < epb;
1872 i += cdnp->dn_extra_slots + 1,
1873 cdnp += cdnp->dn_extra_slots + 1) {
1874 dsl_scan_visitdnode(scn, ds, ostype,
1875 cdnp, zb->zb_blkid * epb + i, tx);
1878 arc_buf_destroy(buf, &buf);
1879 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
1880 arc_flags_t flags = ARC_FLAG_WAIT;
1884 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1885 ZIO_PRIORITY_SCRUB, zio_flags, &flags, zb);
1887 scn->scn_phys.scn_errors++;
1893 dsl_scan_visitdnode(scn, ds, osp->os_type,
1894 &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx);
1896 if (OBJSET_BUF_HAS_USERUSED(buf)) {
1898 * We also always visit user/group/project accounting
1899 * objects, and never skip them, even if we are
1900 * suspending. This is necessary so that the
1901 * space deltas from this txg get integrated.
1903 if (OBJSET_BUF_HAS_PROJECTUSED(buf))
1904 dsl_scan_visitdnode(scn, ds, osp->os_type,
1905 &osp->os_projectused_dnode,
1906 DMU_PROJECTUSED_OBJECT, tx);
1907 dsl_scan_visitdnode(scn, ds, osp->os_type,
1908 &osp->os_groupused_dnode,
1909 DMU_GROUPUSED_OBJECT, tx);
1910 dsl_scan_visitdnode(scn, ds, osp->os_type,
1911 &osp->os_userused_dnode,
1912 DMU_USERUSED_OBJECT, tx);
1914 arc_buf_destroy(buf, &buf);
1920 inline __attribute__((always_inline)) static void
1921 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
1922 dmu_objset_type_t ostype, dnode_phys_t *dnp,
1923 uint64_t object, dmu_tx_t *tx)
1927 for (j = 0; j < dnp->dn_nblkptr; j++) {
1928 zbookmark_phys_t czb;
1930 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
1931 dnp->dn_nlevels - 1, j);
1932 dsl_scan_visitbp(&dnp->dn_blkptr[j],
1933 &czb, dnp, ds, scn, ostype, tx);
1936 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
1937 zbookmark_phys_t czb;
1938 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
1939 0, DMU_SPILL_BLKID);
1940 dsl_scan_visitbp(DN_SPILL_BLKPTR(dnp),
1941 &czb, dnp, ds, scn, ostype, tx);
1946 * The arguments are in this order because mdb can only print the
1947 * first 5; we want them to be useful.
1950 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
1951 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
1952 dmu_objset_type_t ostype, dmu_tx_t *tx)
1954 dsl_pool_t *dp = scn->scn_dp;
1955 blkptr_t *bp_toread = NULL;
1957 if (dsl_scan_check_suspend(scn, zb))
1960 if (dsl_scan_check_resume(scn, dnp, zb))
1963 scn->scn_visited_this_txg++;
1966 * This debugging is commented out to conserve stack space. This
1967 * function is called recursively and the debugging adds several
1968 * bytes to the stack for each call. It can be commented back in
1969 * if required to debug an issue in dsl_scan_visitbp().
1972 * "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
1973 * ds, ds ? ds->ds_object : 0,
1974 * zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
1978 if (BP_IS_HOLE(bp)) {
1979 scn->scn_holes_this_txg++;
1983 if (BP_IS_REDACTED(bp)) {
1984 ASSERT(dsl_dataset_feature_is_active(ds,
1985 SPA_FEATURE_REDACTED_DATASETS));
1989 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg) {
1990 scn->scn_lt_min_this_txg++;
1994 bp_toread = kmem_alloc(sizeof (blkptr_t), KM_SLEEP);
1997 if (dsl_scan_recurse(scn, ds, ostype, dnp, bp_toread, zb, tx) != 0)
2001 * If dsl_scan_ddt() has already visited this block, it will have
2002 * already done any translations or scrubbing, so don't call the
2005 if (ddt_class_contains(dp->dp_spa,
2006 scn->scn_phys.scn_ddt_class_max, bp)) {
2007 scn->scn_ddt_contained_this_txg++;
2012 * If this block is from the future (after cur_max_txg), then we
2013 * are doing this on behalf of a deleted snapshot, and we will
2014 * revisit the future block on the next pass of this dataset.
2015 * Don't scan it now unless we need to because something
2016 * under it was modified.
2018 if (BP_PHYSICAL_BIRTH(bp) > scn->scn_phys.scn_cur_max_txg) {
2019 scn->scn_gt_max_this_txg++;
2023 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
2026 kmem_free(bp_toread, sizeof (blkptr_t));
2030 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
2033 zbookmark_phys_t zb;
2034 scan_prefetch_ctx_t *spc;
2036 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
2037 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
2039 if (ZB_IS_ZERO(&scn->scn_phys.scn_bookmark)) {
2040 SET_BOOKMARK(&scn->scn_prefetch_bookmark,
2041 zb.zb_objset, 0, 0, 0);
2043 scn->scn_prefetch_bookmark = scn->scn_phys.scn_bookmark;
2046 scn->scn_objsets_visited_this_txg++;
2048 spc = scan_prefetch_ctx_create(scn, NULL, FTAG);
2049 dsl_scan_prefetch(spc, bp, &zb);
2050 scan_prefetch_ctx_rele(spc, FTAG);
2052 dsl_scan_visitbp(bp, &zb, NULL, ds, scn, DMU_OST_NONE, tx);
2054 dprintf_ds(ds, "finished scan%s", "");
2058 ds_destroyed_scn_phys(dsl_dataset_t *ds, dsl_scan_phys_t *scn_phys)
2060 if (scn_phys->scn_bookmark.zb_objset == ds->ds_object) {
2061 if (ds->ds_is_snapshot) {
2064 * - scn_cur_{min,max}_txg stays the same.
2065 * - Setting the flag is not really necessary if
2066 * scn_cur_max_txg == scn_max_txg, because there
2067 * is nothing after this snapshot that we care
2068 * about. However, we set it anyway and then
2069 * ignore it when we retraverse it in
2070 * dsl_scan_visitds().
2072 scn_phys->scn_bookmark.zb_objset =
2073 dsl_dataset_phys(ds)->ds_next_snap_obj;
2074 zfs_dbgmsg("destroying ds %llu on %s; currently "
2075 "traversing; reset zb_objset to %llu",
2076 (u_longlong_t)ds->ds_object,
2077 ds->ds_dir->dd_pool->dp_spa->spa_name,
2078 (u_longlong_t)dsl_dataset_phys(ds)->
2080 scn_phys->scn_flags |= DSF_VISIT_DS_AGAIN;
2082 SET_BOOKMARK(&scn_phys->scn_bookmark,
2083 ZB_DESTROYED_OBJSET, 0, 0, 0);
2084 zfs_dbgmsg("destroying ds %llu on %s; currently "
2085 "traversing; reset bookmark to -1,0,0,0",
2086 (u_longlong_t)ds->ds_object,
2087 ds->ds_dir->dd_pool->dp_spa->spa_name);
2093 * Invoked when a dataset is destroyed. We need to make sure that:
2095 * 1) If it is the dataset that was currently being scanned, we write
2096 * a new dsl_scan_phys_t and marking the objset reference in it
2098 * 2) Remove it from the work queue, if it was present.
2100 * If the dataset was actually a snapshot, instead of marking the dataset
2101 * as destroyed, we instead substitute the next snapshot in line.
2104 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
2106 dsl_pool_t *dp = ds->ds_dir->dd_pool;
2107 dsl_scan_t *scn = dp->dp_scan;
2110 if (!dsl_scan_is_running(scn))
2113 ds_destroyed_scn_phys(ds, &scn->scn_phys);
2114 ds_destroyed_scn_phys(ds, &scn->scn_phys_cached);
2116 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
2117 scan_ds_queue_remove(scn, ds->ds_object);
2118 if (ds->ds_is_snapshot)
2119 scan_ds_queue_insert(scn,
2120 dsl_dataset_phys(ds)->ds_next_snap_obj, mintxg);
2123 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
2124 ds->ds_object, &mintxg) == 0) {
2125 ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
2126 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
2127 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
2128 if (ds->ds_is_snapshot) {
2130 * We keep the same mintxg; it could be >
2131 * ds_creation_txg if the previous snapshot was
2134 VERIFY(zap_add_int_key(dp->dp_meta_objset,
2135 scn->scn_phys.scn_queue_obj,
2136 dsl_dataset_phys(ds)->ds_next_snap_obj,
2138 zfs_dbgmsg("destroying ds %llu on %s; in queue; "
2139 "replacing with %llu",
2140 (u_longlong_t)ds->ds_object,
2141 dp->dp_spa->spa_name,
2142 (u_longlong_t)dsl_dataset_phys(ds)->
2145 zfs_dbgmsg("destroying ds %llu on %s; in queue; "
2147 (u_longlong_t)ds->ds_object,
2148 dp->dp_spa->spa_name);
2153 * dsl_scan_sync() should be called after this, and should sync
2154 * out our changed state, but just to be safe, do it here.
2156 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
2160 ds_snapshotted_bookmark(dsl_dataset_t *ds, zbookmark_phys_t *scn_bookmark)
2162 if (scn_bookmark->zb_objset == ds->ds_object) {
2163 scn_bookmark->zb_objset =
2164 dsl_dataset_phys(ds)->ds_prev_snap_obj;
2165 zfs_dbgmsg("snapshotting ds %llu on %s; currently traversing; "
2166 "reset zb_objset to %llu",
2167 (u_longlong_t)ds->ds_object,
2168 ds->ds_dir->dd_pool->dp_spa->spa_name,
2169 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
2174 * Called when a dataset is snapshotted. If we were currently traversing
2175 * this snapshot, we reset our bookmark to point at the newly created
2176 * snapshot. We also modify our work queue to remove the old snapshot and
2177 * replace with the new one.
2180 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
2182 dsl_pool_t *dp = ds->ds_dir->dd_pool;
2183 dsl_scan_t *scn = dp->dp_scan;
2186 if (!dsl_scan_is_running(scn))
2189 ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
2191 ds_snapshotted_bookmark(ds, &scn->scn_phys.scn_bookmark);
2192 ds_snapshotted_bookmark(ds, &scn->scn_phys_cached.scn_bookmark);
2194 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
2195 scan_ds_queue_remove(scn, ds->ds_object);
2196 scan_ds_queue_insert(scn,
2197 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg);
2200 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
2201 ds->ds_object, &mintxg) == 0) {
2202 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
2203 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
2204 VERIFY(zap_add_int_key(dp->dp_meta_objset,
2205 scn->scn_phys.scn_queue_obj,
2206 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg, tx) == 0);
2207 zfs_dbgmsg("snapshotting ds %llu on %s; in queue; "
2208 "replacing with %llu",
2209 (u_longlong_t)ds->ds_object,
2210 dp->dp_spa->spa_name,
2211 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
2214 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
2218 ds_clone_swapped_bookmark(dsl_dataset_t *ds1, dsl_dataset_t *ds2,
2219 zbookmark_phys_t *scn_bookmark)
2221 if (scn_bookmark->zb_objset == ds1->ds_object) {
2222 scn_bookmark->zb_objset = ds2->ds_object;
2223 zfs_dbgmsg("clone_swap ds %llu on %s; currently traversing; "
2224 "reset zb_objset to %llu",
2225 (u_longlong_t)ds1->ds_object,
2226 ds1->ds_dir->dd_pool->dp_spa->spa_name,
2227 (u_longlong_t)ds2->ds_object);
2228 } else if (scn_bookmark->zb_objset == ds2->ds_object) {
2229 scn_bookmark->zb_objset = ds1->ds_object;
2230 zfs_dbgmsg("clone_swap ds %llu on %s; currently traversing; "
2231 "reset zb_objset to %llu",
2232 (u_longlong_t)ds2->ds_object,
2233 ds2->ds_dir->dd_pool->dp_spa->spa_name,
2234 (u_longlong_t)ds1->ds_object);
2239 * Called when an origin dataset and its clone are swapped. If we were
2240 * currently traversing the dataset, we need to switch to traversing the
2241 * newly promoted clone.
2244 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
2246 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
2247 dsl_scan_t *scn = dp->dp_scan;
2248 uint64_t mintxg1, mintxg2;
2249 boolean_t ds1_queued, ds2_queued;
2251 if (!dsl_scan_is_running(scn))
2254 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys.scn_bookmark);
2255 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys_cached.scn_bookmark);
2258 * Handle the in-memory scan queue.
2260 ds1_queued = scan_ds_queue_contains(scn, ds1->ds_object, &mintxg1);
2261 ds2_queued = scan_ds_queue_contains(scn, ds2->ds_object, &mintxg2);
2263 /* Sanity checking. */
2265 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2266 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2269 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2270 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2273 if (ds1_queued && ds2_queued) {
2275 * If both are queued, we don't need to do anything.
2276 * The swapping code below would not handle this case correctly,
2277 * since we can't insert ds2 if it is already there. That's
2278 * because scan_ds_queue_insert() prohibits a duplicate insert
2281 } else if (ds1_queued) {
2282 scan_ds_queue_remove(scn, ds1->ds_object);
2283 scan_ds_queue_insert(scn, ds2->ds_object, mintxg1);
2284 } else if (ds2_queued) {
2285 scan_ds_queue_remove(scn, ds2->ds_object);
2286 scan_ds_queue_insert(scn, ds1->ds_object, mintxg2);
2290 * Handle the on-disk scan queue.
2291 * The on-disk state is an out-of-date version of the in-memory state,
2292 * so the in-memory and on-disk values for ds1_queued and ds2_queued may
2293 * be different. Therefore we need to apply the swap logic to the
2294 * on-disk state independently of the in-memory state.
2296 ds1_queued = zap_lookup_int_key(dp->dp_meta_objset,
2297 scn->scn_phys.scn_queue_obj, ds1->ds_object, &mintxg1) == 0;
2298 ds2_queued = zap_lookup_int_key(dp->dp_meta_objset,
2299 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg2) == 0;
2301 /* Sanity checking. */
2303 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2304 ASSERT3U(mintxg1, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2307 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
2308 ASSERT3U(mintxg2, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
2311 if (ds1_queued && ds2_queued) {
2313 * If both are queued, we don't need to do anything.
2314 * Alternatively, we could check for EEXIST from
2315 * zap_add_int_key() and back out to the original state, but
2316 * that would be more work than checking for this case upfront.
2318 } else if (ds1_queued) {
2319 VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset,
2320 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
2321 VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset,
2322 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg1, tx));
2323 zfs_dbgmsg("clone_swap ds %llu on %s; in queue; "
2324 "replacing with %llu",
2325 (u_longlong_t)ds1->ds_object,
2326 dp->dp_spa->spa_name,
2327 (u_longlong_t)ds2->ds_object);
2328 } else if (ds2_queued) {
2329 VERIFY3S(0, ==, zap_remove_int(dp->dp_meta_objset,
2330 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
2331 VERIFY3S(0, ==, zap_add_int_key(dp->dp_meta_objset,
2332 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg2, tx));
2333 zfs_dbgmsg("clone_swap ds %llu on %s; in queue; "
2334 "replacing with %llu",
2335 (u_longlong_t)ds2->ds_object,
2336 dp->dp_spa->spa_name,
2337 (u_longlong_t)ds1->ds_object);
2340 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
2345 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
2347 uint64_t originobj = *(uint64_t *)arg;
2350 dsl_scan_t *scn = dp->dp_scan;
2352 if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != originobj)
2355 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
2359 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != originobj) {
2360 dsl_dataset_t *prev;
2361 err = dsl_dataset_hold_obj(dp,
2362 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
2364 dsl_dataset_rele(ds, FTAG);
2369 scan_ds_queue_insert(scn, ds->ds_object,
2370 dsl_dataset_phys(ds)->ds_prev_snap_txg);
2371 dsl_dataset_rele(ds, FTAG);
2376 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
2378 dsl_pool_t *dp = scn->scn_dp;
2381 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
2383 if (scn->scn_phys.scn_cur_min_txg >=
2384 scn->scn_phys.scn_max_txg) {
2386 * This can happen if this snapshot was created after the
2387 * scan started, and we already completed a previous snapshot
2388 * that was created after the scan started. This snapshot
2389 * only references blocks with:
2391 * birth < our ds_creation_txg
2392 * cur_min_txg is no less than ds_creation_txg.
2393 * We have already visited these blocks.
2395 * birth > scn_max_txg
2396 * The scan requested not to visit these blocks.
2398 * Subsequent snapshots (and clones) can reference our
2399 * blocks, or blocks with even higher birth times.
2400 * Therefore we do not need to visit them either,
2401 * so we do not add them to the work queue.
2403 * Note that checking for cur_min_txg >= cur_max_txg
2404 * is not sufficient, because in that case we may need to
2405 * visit subsequent snapshots. This happens when min_txg > 0,
2406 * which raises cur_min_txg. In this case we will visit
2407 * this dataset but skip all of its blocks, because the
2408 * rootbp's birth time is < cur_min_txg. Then we will
2409 * add the next snapshots/clones to the work queue.
2411 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
2412 dsl_dataset_name(ds, dsname);
2413 zfs_dbgmsg("scanning dataset %llu (%s) is unnecessary because "
2414 "cur_min_txg (%llu) >= max_txg (%llu)",
2415 (longlong_t)dsobj, dsname,
2416 (longlong_t)scn->scn_phys.scn_cur_min_txg,
2417 (longlong_t)scn->scn_phys.scn_max_txg);
2418 kmem_free(dsname, MAXNAMELEN);
2424 * Only the ZIL in the head (non-snapshot) is valid. Even though
2425 * snapshots can have ZIL block pointers (which may be the same
2426 * BP as in the head), they must be ignored. In addition, $ORIGIN
2427 * doesn't have a objset (i.e. its ds_bp is a hole) so we don't
2428 * need to look for a ZIL in it either. So we traverse the ZIL here,
2429 * rather than in scan_recurse(), because the regular snapshot
2430 * block-sharing rules don't apply to it.
2432 if (!dsl_dataset_is_snapshot(ds) &&
2433 (dp->dp_origin_snap == NULL ||
2434 ds->ds_dir != dp->dp_origin_snap->ds_dir)) {
2436 if (dmu_objset_from_ds(ds, &os) != 0) {
2439 dsl_scan_zil(dp, &os->os_zil_header);
2443 * Iterate over the bps in this ds.
2445 dmu_buf_will_dirty(ds->ds_dbuf, tx);
2446 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
2447 dsl_scan_visit_rootbp(scn, ds, &dsl_dataset_phys(ds)->ds_bp, tx);
2448 rrw_exit(&ds->ds_bp_rwlock, FTAG);
2450 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
2451 dsl_dataset_name(ds, dsname);
2452 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
2454 (longlong_t)dsobj, dsname,
2455 (longlong_t)scn->scn_phys.scn_cur_min_txg,
2456 (longlong_t)scn->scn_phys.scn_cur_max_txg,
2457 (int)scn->scn_suspending);
2458 kmem_free(dsname, ZFS_MAX_DATASET_NAME_LEN);
2460 if (scn->scn_suspending)
2464 * We've finished this pass over this dataset.
2468 * If we did not completely visit this dataset, do another pass.
2470 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
2471 zfs_dbgmsg("incomplete pass on %s; visiting again",
2472 dp->dp_spa->spa_name);
2473 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
2474 scan_ds_queue_insert(scn, ds->ds_object,
2475 scn->scn_phys.scn_cur_max_txg);
2480 * Add descendant datasets to work queue.
2482 if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
2483 scan_ds_queue_insert(scn,
2484 dsl_dataset_phys(ds)->ds_next_snap_obj,
2485 dsl_dataset_phys(ds)->ds_creation_txg);
2487 if (dsl_dataset_phys(ds)->ds_num_children > 1) {
2488 boolean_t usenext = B_FALSE;
2489 if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
2492 * A bug in a previous version of the code could
2493 * cause upgrade_clones_cb() to not set
2494 * ds_next_snap_obj when it should, leading to a
2495 * missing entry. Therefore we can only use the
2496 * next_clones_obj when its count is correct.
2498 int err = zap_count(dp->dp_meta_objset,
2499 dsl_dataset_phys(ds)->ds_next_clones_obj, &count);
2501 count == dsl_dataset_phys(ds)->ds_num_children - 1)
2508 for (zap_cursor_init(&zc, dp->dp_meta_objset,
2509 dsl_dataset_phys(ds)->ds_next_clones_obj);
2510 zap_cursor_retrieve(&zc, &za) == 0;
2511 (void) zap_cursor_advance(&zc)) {
2512 scan_ds_queue_insert(scn,
2513 zfs_strtonum(za.za_name, NULL),
2514 dsl_dataset_phys(ds)->ds_creation_txg);
2516 zap_cursor_fini(&zc);
2518 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
2519 enqueue_clones_cb, &ds->ds_object,
2525 dsl_dataset_rele(ds, FTAG);
2530 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
2534 dsl_scan_t *scn = dp->dp_scan;
2536 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
2540 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
2541 dsl_dataset_t *prev;
2542 err = dsl_dataset_hold_obj(dp,
2543 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
2545 dsl_dataset_rele(ds, FTAG);
2550 * If this is a clone, we don't need to worry about it for now.
2552 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) {
2553 dsl_dataset_rele(ds, FTAG);
2554 dsl_dataset_rele(prev, FTAG);
2557 dsl_dataset_rele(ds, FTAG);
2561 scan_ds_queue_insert(scn, ds->ds_object,
2562 dsl_dataset_phys(ds)->ds_prev_snap_txg);
2563 dsl_dataset_rele(ds, FTAG);
2569 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
2570 ddt_entry_t *dde, dmu_tx_t *tx)
2572 const ddt_key_t *ddk = &dde->dde_key;
2573 ddt_phys_t *ddp = dde->dde_phys;
2575 zbookmark_phys_t zb = { 0 };
2578 if (!dsl_scan_is_running(scn))
2582 * This function is special because it is the only thing
2583 * that can add scan_io_t's to the vdev scan queues from
2584 * outside dsl_scan_sync(). For the most part this is ok
2585 * as long as it is called from within syncing context.
2586 * However, dsl_scan_sync() expects that no new sio's will
2587 * be added between when all the work for a scan is done
2588 * and the next txg when the scan is actually marked as
2589 * completed. This check ensures we do not issue new sio's
2590 * during this period.
2592 if (scn->scn_done_txg != 0)
2595 for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
2596 if (ddp->ddp_phys_birth == 0 ||
2597 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
2599 ddt_bp_create(checksum, ddk, ddp, &bp);
2601 scn->scn_visited_this_txg++;
2602 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
2607 * Scrub/dedup interaction.
2609 * If there are N references to a deduped block, we don't want to scrub it
2610 * N times -- ideally, we should scrub it exactly once.
2612 * We leverage the fact that the dde's replication class (enum ddt_class)
2613 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
2614 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
2616 * To prevent excess scrubbing, the scrub begins by walking the DDT
2617 * to find all blocks with refcnt > 1, and scrubs each of these once.
2618 * Since there are two replication classes which contain blocks with
2619 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
2620 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
2622 * There would be nothing more to say if a block's refcnt couldn't change
2623 * during a scrub, but of course it can so we must account for changes
2624 * in a block's replication class.
2626 * Here's an example of what can occur:
2628 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
2629 * when visited during the top-down scrub phase, it will be scrubbed twice.
2630 * This negates our scrub optimization, but is otherwise harmless.
2632 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
2633 * on each visit during the top-down scrub phase, it will never be scrubbed.
2634 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
2635 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
2636 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
2637 * while a scrub is in progress, it scrubs the block right then.
2640 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
2642 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
2647 bzero(&dde, sizeof (ddt_entry_t));
2649 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
2652 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
2654 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
2655 (longlong_t)ddb->ddb_class,
2656 (longlong_t)ddb->ddb_type,
2657 (longlong_t)ddb->ddb_checksum,
2658 (longlong_t)ddb->ddb_cursor);
2660 /* There should be no pending changes to the dedup table */
2661 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
2662 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
2664 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
2667 if (dsl_scan_check_suspend(scn, NULL))
2671 zfs_dbgmsg("scanned %llu ddt entries on %s with class_max = %u; "
2672 "suspending=%u", (longlong_t)n, scn->scn_dp->dp_spa->spa_name,
2673 (int)scn->scn_phys.scn_ddt_class_max, (int)scn->scn_suspending);
2675 ASSERT(error == 0 || error == ENOENT);
2676 ASSERT(error != ENOENT ||
2677 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
2681 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
2683 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
2684 if (ds->ds_is_snapshot)
2685 return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
2690 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
2693 dsl_pool_t *dp = scn->scn_dp;
2695 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
2696 scn->scn_phys.scn_ddt_class_max) {
2697 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
2698 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
2699 dsl_scan_ddt(scn, tx);
2700 if (scn->scn_suspending)
2704 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
2705 /* First do the MOS & ORIGIN */
2707 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
2708 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
2709 dsl_scan_visit_rootbp(scn, NULL,
2710 &dp->dp_meta_rootbp, tx);
2711 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
2712 if (scn->scn_suspending)
2715 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
2716 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
2717 enqueue_cb, NULL, DS_FIND_CHILDREN));
2719 dsl_scan_visitds(scn,
2720 dp->dp_origin_snap->ds_object, tx);
2722 ASSERT(!scn->scn_suspending);
2723 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
2724 ZB_DESTROYED_OBJSET) {
2725 uint64_t dsobj = scn->scn_phys.scn_bookmark.zb_objset;
2727 * If we were suspended, continue from here. Note if the
2728 * ds we were suspended on was deleted, the zb_objset may
2729 * be -1, so we will skip this and find a new objset
2732 dsl_scan_visitds(scn, dsobj, tx);
2733 if (scn->scn_suspending)
2738 * In case we suspended right at the end of the ds, zero the
2739 * bookmark so we don't think that we're still trying to resume.
2741 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_phys_t));
2744 * Keep pulling things out of the dataset avl queue. Updates to the
2745 * persistent zap-object-as-queue happen only at checkpoints.
2747 while ((sds = avl_first(&scn->scn_queue)) != NULL) {
2749 uint64_t dsobj = sds->sds_dsobj;
2750 uint64_t txg = sds->sds_txg;
2752 /* dequeue and free the ds from the queue */
2753 scan_ds_queue_remove(scn, dsobj);
2756 /* set up min / max txg */
2757 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
2759 scn->scn_phys.scn_cur_min_txg =
2760 MAX(scn->scn_phys.scn_min_txg, txg);
2762 scn->scn_phys.scn_cur_min_txg =
2763 MAX(scn->scn_phys.scn_min_txg,
2764 dsl_dataset_phys(ds)->ds_prev_snap_txg);
2766 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
2767 dsl_dataset_rele(ds, FTAG);
2769 dsl_scan_visitds(scn, dsobj, tx);
2770 if (scn->scn_suspending)
2774 /* No more objsets to fetch, we're done */
2775 scn->scn_phys.scn_bookmark.zb_objset = ZB_DESTROYED_OBJSET;
2776 ASSERT0(scn->scn_suspending);
2780 dsl_scan_count_data_disks(vdev_t *rvd)
2782 uint64_t i, leaves = 0;
2784 for (i = 0; i < rvd->vdev_children; i++) {
2785 vdev_t *vd = rvd->vdev_child[i];
2786 if (vd->vdev_islog || vd->vdev_isspare || vd->vdev_isl2cache)
2788 leaves += vdev_get_ndisks(vd) - vdev_get_nparity(vd);
2794 scan_io_queues_update_zio_stats(dsl_scan_io_queue_t *q, const blkptr_t *bp)
2797 uint64_t cur_size = 0;
2799 for (i = 0; i < BP_GET_NDVAS(bp); i++) {
2800 cur_size += DVA_GET_ASIZE(&bp->blk_dva[i]);
2803 q->q_total_zio_size_this_txg += cur_size;
2804 q->q_zios_this_txg++;
2808 scan_io_queues_update_seg_stats(dsl_scan_io_queue_t *q, uint64_t start,
2811 q->q_total_seg_size_this_txg += end - start;
2812 q->q_segs_this_txg++;
2816 scan_io_queue_check_suspend(dsl_scan_t *scn)
2818 /* See comment in dsl_scan_check_suspend() */
2819 uint64_t curr_time_ns = gethrtime();
2820 uint64_t scan_time_ns = curr_time_ns - scn->scn_sync_start_time;
2821 uint64_t sync_time_ns = curr_time_ns -
2822 scn->scn_dp->dp_spa->spa_sync_starttime;
2823 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
2824 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
2825 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
2827 return ((NSEC2MSEC(scan_time_ns) > mintime &&
2828 (dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent ||
2829 txg_sync_waiting(scn->scn_dp) ||
2830 NSEC2SEC(sync_time_ns) >= zfs_txg_timeout)) ||
2831 spa_shutting_down(scn->scn_dp->dp_spa));
2835 * Given a list of scan_io_t's in io_list, this issues the I/Os out to
2836 * disk. This consumes the io_list and frees the scan_io_t's. This is
2837 * called when emptying queues, either when we're up against the memory
2838 * limit or when we have finished scanning. Returns B_TRUE if we stopped
2839 * processing the list before we finished. Any sios that were not issued
2840 * will remain in the io_list.
2843 scan_io_queue_issue(dsl_scan_io_queue_t *queue, list_t *io_list)
2845 dsl_scan_t *scn = queue->q_scn;
2847 int64_t bytes_issued = 0;
2848 boolean_t suspended = B_FALSE;
2850 while ((sio = list_head(io_list)) != NULL) {
2853 if (scan_io_queue_check_suspend(scn)) {
2859 bytes_issued += SIO_GET_ASIZE(sio);
2860 scan_exec_io(scn->scn_dp, &bp, sio->sio_flags,
2861 &sio->sio_zb, queue);
2862 (void) list_remove_head(io_list);
2863 scan_io_queues_update_zio_stats(queue, &bp);
2867 atomic_add_64(&scn->scn_bytes_pending, -bytes_issued);
2873 * This function removes sios from an IO queue which reside within a given
2874 * range_seg_t and inserts them (in offset order) into a list. Note that
2875 * we only ever return a maximum of 32 sios at once. If there are more sios
2876 * to process within this segment that did not make it onto the list we
2877 * return B_TRUE and otherwise B_FALSE.
2880 scan_io_queue_gather(dsl_scan_io_queue_t *queue, range_seg_t *rs, list_t *list)
2882 scan_io_t *srch_sio, *sio, *next_sio;
2884 uint_t num_sios = 0;
2885 int64_t bytes_issued = 0;
2888 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
2890 srch_sio = sio_alloc(1);
2891 srch_sio->sio_nr_dvas = 1;
2892 SIO_SET_OFFSET(srch_sio, rs_get_start(rs, queue->q_exts_by_addr));
2895 * The exact start of the extent might not contain any matching zios,
2896 * so if that's the case, examine the next one in the tree.
2898 sio = avl_find(&queue->q_sios_by_addr, srch_sio, &idx);
2902 sio = avl_nearest(&queue->q_sios_by_addr, idx, AVL_AFTER);
2904 while (sio != NULL && SIO_GET_OFFSET(sio) < rs_get_end(rs,
2905 queue->q_exts_by_addr) && num_sios <= 32) {
2906 ASSERT3U(SIO_GET_OFFSET(sio), >=, rs_get_start(rs,
2907 queue->q_exts_by_addr));
2908 ASSERT3U(SIO_GET_END_OFFSET(sio), <=, rs_get_end(rs,
2909 queue->q_exts_by_addr));
2911 next_sio = AVL_NEXT(&queue->q_sios_by_addr, sio);
2912 avl_remove(&queue->q_sios_by_addr, sio);
2913 queue->q_sio_memused -= SIO_GET_MUSED(sio);
2915 bytes_issued += SIO_GET_ASIZE(sio);
2917 list_insert_tail(list, sio);
2922 * We limit the number of sios we process at once to 32 to avoid
2923 * biting off more than we can chew. If we didn't take everything
2924 * in the segment we update it to reflect the work we were able to
2925 * complete. Otherwise, we remove it from the range tree entirely.
2927 if (sio != NULL && SIO_GET_OFFSET(sio) < rs_get_end(rs,
2928 queue->q_exts_by_addr)) {
2929 range_tree_adjust_fill(queue->q_exts_by_addr, rs,
2931 range_tree_resize_segment(queue->q_exts_by_addr, rs,
2932 SIO_GET_OFFSET(sio), rs_get_end(rs,
2933 queue->q_exts_by_addr) - SIO_GET_OFFSET(sio));
2937 uint64_t rstart = rs_get_start(rs, queue->q_exts_by_addr);
2938 uint64_t rend = rs_get_end(rs, queue->q_exts_by_addr);
2939 range_tree_remove(queue->q_exts_by_addr, rstart, rend - rstart);
2945 * This is called from the queue emptying thread and selects the next
2946 * extent from which we are to issue I/Os. The behavior of this function
2947 * depends on the state of the scan, the current memory consumption and
2948 * whether or not we are performing a scan shutdown.
2949 * 1) We select extents in an elevator algorithm (LBA-order) if the scan
2950 * needs to perform a checkpoint
2951 * 2) We select the largest available extent if we are up against the
2953 * 3) Otherwise we don't select any extents.
2955 static range_seg_t *
2956 scan_io_queue_fetch_ext(dsl_scan_io_queue_t *queue)
2958 dsl_scan_t *scn = queue->q_scn;
2959 range_tree_t *rt = queue->q_exts_by_addr;
2961 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
2962 ASSERT(scn->scn_is_sorted);
2964 /* handle tunable overrides */
2965 if (scn->scn_checkpointing || scn->scn_clearing) {
2966 if (zfs_scan_issue_strategy == 1) {
2967 return (range_tree_first(rt));
2968 } else if (zfs_scan_issue_strategy == 2) {
2970 * We need to get the original entry in the by_addr
2971 * tree so we can modify it.
2973 range_seg_t *size_rs =
2974 zfs_btree_first(&queue->q_exts_by_size, NULL);
2975 if (size_rs == NULL)
2977 uint64_t start = rs_get_start(size_rs, rt);
2978 uint64_t size = rs_get_end(size_rs, rt) - start;
2979 range_seg_t *addr_rs = range_tree_find(rt, start,
2981 ASSERT3P(addr_rs, !=, NULL);
2982 ASSERT3U(rs_get_start(size_rs, rt), ==,
2983 rs_get_start(addr_rs, rt));
2984 ASSERT3U(rs_get_end(size_rs, rt), ==,
2985 rs_get_end(addr_rs, rt));
2991 * During normal clearing, we want to issue our largest segments
2992 * first, keeping IO as sequential as possible, and leaving the
2993 * smaller extents for later with the hope that they might eventually
2994 * grow to larger sequential segments. However, when the scan is
2995 * checkpointing, no new extents will be added to the sorting queue,
2996 * so the way we are sorted now is as good as it will ever get.
2997 * In this case, we instead switch to issuing extents in LBA order.
2999 if (scn->scn_checkpointing) {
3000 return (range_tree_first(rt));
3001 } else if (scn->scn_clearing) {
3003 * We need to get the original entry in the by_addr
3004 * tree so we can modify it.
3006 range_seg_t *size_rs = zfs_btree_first(&queue->q_exts_by_size,
3008 if (size_rs == NULL)
3010 uint64_t start = rs_get_start(size_rs, rt);
3011 uint64_t size = rs_get_end(size_rs, rt) - start;
3012 range_seg_t *addr_rs = range_tree_find(rt, start, size);
3013 ASSERT3P(addr_rs, !=, NULL);
3014 ASSERT3U(rs_get_start(size_rs, rt), ==, rs_get_start(addr_rs,
3016 ASSERT3U(rs_get_end(size_rs, rt), ==, rs_get_end(addr_rs, rt));
3024 scan_io_queues_run_one(void *arg)
3026 dsl_scan_io_queue_t *queue = arg;
3027 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock;
3028 boolean_t suspended = B_FALSE;
3029 range_seg_t *rs = NULL;
3030 scan_io_t *sio = NULL;
3033 ASSERT(queue->q_scn->scn_is_sorted);
3035 list_create(&sio_list, sizeof (scan_io_t),
3036 offsetof(scan_io_t, sio_nodes.sio_list_node));
3037 mutex_enter(q_lock);
3039 /* Calculate maximum in-flight bytes for this vdev. */
3040 queue->q_maxinflight_bytes = MAX(1, zfs_scan_vdev_limit *
3041 (vdev_get_ndisks(queue->q_vd) - vdev_get_nparity(queue->q_vd)));
3043 /* reset per-queue scan statistics for this txg */
3044 queue->q_total_seg_size_this_txg = 0;
3045 queue->q_segs_this_txg = 0;
3046 queue->q_total_zio_size_this_txg = 0;
3047 queue->q_zios_this_txg = 0;
3049 /* loop until we run out of time or sios */
3050 while ((rs = scan_io_queue_fetch_ext(queue)) != NULL) {
3051 uint64_t seg_start = 0, seg_end = 0;
3052 boolean_t more_left = B_TRUE;
3054 ASSERT(list_is_empty(&sio_list));
3056 /* loop while we still have sios left to process in this rs */
3058 scan_io_t *first_sio, *last_sio;
3061 * We have selected which extent needs to be
3062 * processed next. Gather up the corresponding sios.
3064 more_left = scan_io_queue_gather(queue, rs, &sio_list);
3065 ASSERT(!list_is_empty(&sio_list));
3066 first_sio = list_head(&sio_list);
3067 last_sio = list_tail(&sio_list);
3069 seg_end = SIO_GET_END_OFFSET(last_sio);
3071 seg_start = SIO_GET_OFFSET(first_sio);
3074 * Issuing sios can take a long time so drop the
3075 * queue lock. The sio queue won't be updated by
3076 * other threads since we're in syncing context so
3077 * we can be sure that our trees will remain exactly
3081 suspended = scan_io_queue_issue(queue, &sio_list);
3082 mutex_enter(q_lock);
3088 /* update statistics for debugging purposes */
3089 scan_io_queues_update_seg_stats(queue, seg_start, seg_end);
3096 * If we were suspended in the middle of processing,
3097 * requeue any unfinished sios and exit.
3099 while ((sio = list_head(&sio_list)) != NULL) {
3100 list_remove(&sio_list, sio);
3101 scan_io_queue_insert_impl(queue, sio);
3105 list_destroy(&sio_list);
3109 * Performs an emptying run on all scan queues in the pool. This just
3110 * punches out one thread per top-level vdev, each of which processes
3111 * only that vdev's scan queue. We can parallelize the I/O here because
3112 * we know that each queue's I/Os only affect its own top-level vdev.
3114 * This function waits for the queue runs to complete, and must be
3115 * called from dsl_scan_sync (or in general, syncing context).
3118 scan_io_queues_run(dsl_scan_t *scn)
3120 spa_t *spa = scn->scn_dp->dp_spa;
3122 ASSERT(scn->scn_is_sorted);
3123 ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
3125 if (scn->scn_bytes_pending == 0)
3128 if (scn->scn_taskq == NULL) {
3129 int nthreads = spa->spa_root_vdev->vdev_children;
3132 * We need to make this taskq *always* execute as many
3133 * threads in parallel as we have top-level vdevs and no
3134 * less, otherwise strange serialization of the calls to
3135 * scan_io_queues_run_one can occur during spa_sync runs
3136 * and that significantly impacts performance.
3138 scn->scn_taskq = taskq_create("dsl_scan_iss", nthreads,
3139 minclsyspri, nthreads, nthreads, TASKQ_PREPOPULATE);
3142 for (uint64_t i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
3143 vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
3145 mutex_enter(&vd->vdev_scan_io_queue_lock);
3146 if (vd->vdev_scan_io_queue != NULL) {
3147 VERIFY(taskq_dispatch(scn->scn_taskq,
3148 scan_io_queues_run_one, vd->vdev_scan_io_queue,
3149 TQ_SLEEP) != TASKQID_INVALID);
3151 mutex_exit(&vd->vdev_scan_io_queue_lock);
3155 * Wait for the queues to finish issuing their IOs for this run
3156 * before we return. There may still be IOs in flight at this
3159 taskq_wait(scn->scn_taskq);
3163 dsl_scan_async_block_should_pause(dsl_scan_t *scn)
3165 uint64_t elapsed_nanosecs;
3170 if (zfs_async_block_max_blocks != 0 &&
3171 scn->scn_visited_this_txg >= zfs_async_block_max_blocks) {
3175 if (zfs_max_async_dedup_frees != 0 &&
3176 scn->scn_dedup_frees_this_txg >= zfs_max_async_dedup_frees) {
3180 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
3181 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
3182 (NSEC2MSEC(elapsed_nanosecs) > scn->scn_async_block_min_time_ms &&
3183 txg_sync_waiting(scn->scn_dp)) ||
3184 spa_shutting_down(scn->scn_dp->dp_spa));
3188 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
3190 dsl_scan_t *scn = arg;
3192 if (!scn->scn_is_bptree ||
3193 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
3194 if (dsl_scan_async_block_should_pause(scn))
3195 return (SET_ERROR(ERESTART));
3198 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
3199 dmu_tx_get_txg(tx), bp, 0));
3200 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
3201 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
3202 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
3203 scn->scn_visited_this_txg++;
3204 if (BP_GET_DEDUP(bp))
3205 scn->scn_dedup_frees_this_txg++;
3210 dsl_scan_update_stats(dsl_scan_t *scn)
3212 spa_t *spa = scn->scn_dp->dp_spa;
3214 uint64_t seg_size_total = 0, zio_size_total = 0;
3215 uint64_t seg_count_total = 0, zio_count_total = 0;
3217 for (i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
3218 vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
3219 dsl_scan_io_queue_t *queue = vd->vdev_scan_io_queue;
3224 seg_size_total += queue->q_total_seg_size_this_txg;
3225 zio_size_total += queue->q_total_zio_size_this_txg;
3226 seg_count_total += queue->q_segs_this_txg;
3227 zio_count_total += queue->q_zios_this_txg;
3230 if (seg_count_total == 0 || zio_count_total == 0) {
3231 scn->scn_avg_seg_size_this_txg = 0;
3232 scn->scn_avg_zio_size_this_txg = 0;
3233 scn->scn_segs_this_txg = 0;
3234 scn->scn_zios_this_txg = 0;
3238 scn->scn_avg_seg_size_this_txg = seg_size_total / seg_count_total;
3239 scn->scn_avg_zio_size_this_txg = zio_size_total / zio_count_total;
3240 scn->scn_segs_this_txg = seg_count_total;
3241 scn->scn_zios_this_txg = zio_count_total;
3245 bpobj_dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
3249 return (dsl_scan_free_block_cb(arg, bp, tx));
3253 dsl_scan_obsolete_block_cb(void *arg, const blkptr_t *bp, boolean_t bp_freed,
3257 dsl_scan_t *scn = arg;
3258 const dva_t *dva = &bp->blk_dva[0];
3260 if (dsl_scan_async_block_should_pause(scn))
3261 return (SET_ERROR(ERESTART));
3263 spa_vdev_indirect_mark_obsolete(scn->scn_dp->dp_spa,
3264 DVA_GET_VDEV(dva), DVA_GET_OFFSET(dva),
3265 DVA_GET_ASIZE(dva), tx);
3266 scn->scn_visited_this_txg++;
3271 dsl_scan_active(dsl_scan_t *scn)
3273 spa_t *spa = scn->scn_dp->dp_spa;
3274 uint64_t used = 0, comp, uncomp;
3275 boolean_t clones_left;
3277 if (spa->spa_load_state != SPA_LOAD_NONE)
3279 if (spa_shutting_down(spa))
3281 if ((dsl_scan_is_running(scn) && !dsl_scan_is_paused_scrub(scn)) ||
3282 (scn->scn_async_destroying && !scn->scn_async_stalled))
3285 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
3286 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
3287 &used, &comp, &uncomp);
3289 clones_left = spa_livelist_delete_check(spa);
3290 return ((used != 0) || (clones_left));
3294 dsl_scan_check_deferred(vdev_t *vd)
3296 boolean_t need_resilver = B_FALSE;
3298 for (int c = 0; c < vd->vdev_children; c++) {
3300 dsl_scan_check_deferred(vd->vdev_child[c]);
3303 if (!vdev_is_concrete(vd) || vd->vdev_aux ||
3304 !vd->vdev_ops->vdev_op_leaf)
3305 return (need_resilver);
3307 if (!vd->vdev_resilver_deferred)
3308 need_resilver = B_TRUE;
3310 return (need_resilver);
3314 dsl_scan_need_resilver(spa_t *spa, const dva_t *dva, size_t psize,
3315 uint64_t phys_birth)
3319 vd = vdev_lookup_top(spa, DVA_GET_VDEV(dva));
3321 if (vd->vdev_ops == &vdev_indirect_ops) {
3323 * The indirect vdev can point to multiple
3324 * vdevs. For simplicity, always create
3325 * the resilver zio_t. zio_vdev_io_start()
3326 * will bypass the child resilver i/o's if
3327 * they are on vdevs that don't have DTL's.
3332 if (DVA_GET_GANG(dva)) {
3334 * Gang members may be spread across multiple
3335 * vdevs, so the best estimate we have is the
3336 * scrub range, which has already been checked.
3337 * XXX -- it would be better to change our
3338 * allocation policy to ensure that all
3339 * gang members reside on the same vdev.
3345 * Check if the top-level vdev must resilver this offset.
3346 * When the offset does not intersect with a dirty leaf DTL
3347 * then it may be possible to skip the resilver IO. The psize
3348 * is provided instead of asize to simplify the check for RAIDZ.
3350 if (!vdev_dtl_need_resilver(vd, dva, psize, phys_birth))
3354 * Check that this top-level vdev has a device under it which
3355 * is resilvering and is not deferred.
3357 if (!dsl_scan_check_deferred(vd))
3364 dsl_process_async_destroys(dsl_pool_t *dp, dmu_tx_t *tx)
3366 dsl_scan_t *scn = dp->dp_scan;
3367 spa_t *spa = dp->dp_spa;
3370 if (spa_suspend_async_destroy(spa))
3373 if (zfs_free_bpobj_enabled &&
3374 spa_version(spa) >= SPA_VERSION_DEADLISTS) {
3375 scn->scn_is_bptree = B_FALSE;
3376 scn->scn_async_block_min_time_ms = zfs_free_min_time_ms;
3377 scn->scn_zio_root = zio_root(spa, NULL,
3378 NULL, ZIO_FLAG_MUSTSUCCEED);
3379 err = bpobj_iterate(&dp->dp_free_bpobj,
3380 bpobj_dsl_scan_free_block_cb, scn, tx);
3381 VERIFY0(zio_wait(scn->scn_zio_root));
3382 scn->scn_zio_root = NULL;
3384 if (err != 0 && err != ERESTART)
3385 zfs_panic_recover("error %u from bpobj_iterate()", err);
3388 if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) {
3389 ASSERT(scn->scn_async_destroying);
3390 scn->scn_is_bptree = B_TRUE;
3391 scn->scn_zio_root = zio_root(spa, NULL,
3392 NULL, ZIO_FLAG_MUSTSUCCEED);
3393 err = bptree_iterate(dp->dp_meta_objset,
3394 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx);
3395 VERIFY0(zio_wait(scn->scn_zio_root));
3396 scn->scn_zio_root = NULL;
3398 if (err == EIO || err == ECKSUM) {
3400 } else if (err != 0 && err != ERESTART) {
3401 zfs_panic_recover("error %u from "
3402 "traverse_dataset_destroyed()", err);
3405 if (bptree_is_empty(dp->dp_meta_objset, dp->dp_bptree_obj)) {
3406 /* finished; deactivate async destroy feature */
3407 spa_feature_decr(spa, SPA_FEATURE_ASYNC_DESTROY, tx);
3408 ASSERT(!spa_feature_is_active(spa,
3409 SPA_FEATURE_ASYNC_DESTROY));
3410 VERIFY0(zap_remove(dp->dp_meta_objset,
3411 DMU_POOL_DIRECTORY_OBJECT,
3412 DMU_POOL_BPTREE_OBJ, tx));
3413 VERIFY0(bptree_free(dp->dp_meta_objset,
3414 dp->dp_bptree_obj, tx));
3415 dp->dp_bptree_obj = 0;
3416 scn->scn_async_destroying = B_FALSE;
3417 scn->scn_async_stalled = B_FALSE;
3420 * If we didn't make progress, mark the async
3421 * destroy as stalled, so that we will not initiate
3422 * a spa_sync() on its behalf. Note that we only
3423 * check this if we are not finished, because if the
3424 * bptree had no blocks for us to visit, we can
3425 * finish without "making progress".
3427 scn->scn_async_stalled =
3428 (scn->scn_visited_this_txg == 0);
3431 if (scn->scn_visited_this_txg) {
3432 zfs_dbgmsg("freed %llu blocks in %llums from "
3433 "free_bpobj/bptree on %s in txg %llu; err=%u",
3434 (longlong_t)scn->scn_visited_this_txg,
3436 NSEC2MSEC(gethrtime() - scn->scn_sync_start_time),
3437 spa->spa_name, (longlong_t)tx->tx_txg, err);
3438 scn->scn_visited_this_txg = 0;
3439 scn->scn_dedup_frees_this_txg = 0;
3442 * Write out changes to the DDT that may be required as a
3443 * result of the blocks freed. This ensures that the DDT
3444 * is clean when a scrub/resilver runs.
3446 ddt_sync(spa, tx->tx_txg);
3450 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying &&
3451 zfs_free_leak_on_eio &&
3452 (dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes != 0 ||
3453 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes != 0 ||
3454 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes != 0)) {
3456 * We have finished background destroying, but there is still
3457 * some space left in the dp_free_dir. Transfer this leaked
3458 * space to the dp_leak_dir.
3460 if (dp->dp_leak_dir == NULL) {
3461 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
3462 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
3464 VERIFY0(dsl_pool_open_special_dir(dp,
3465 LEAK_DIR_NAME, &dp->dp_leak_dir));
3466 rrw_exit(&dp->dp_config_rwlock, FTAG);
3468 dsl_dir_diduse_space(dp->dp_leak_dir, DD_USED_HEAD,
3469 dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
3470 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
3471 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
3472 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
3473 -dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
3474 -dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
3475 -dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
3478 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying &&
3479 !spa_livelist_delete_check(spa)) {
3480 /* finished; verify that space accounting went to zero */
3481 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes);
3482 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes);
3483 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes);
3486 spa_notify_waiters(spa);
3488 EQUIV(bpobj_is_open(&dp->dp_obsolete_bpobj),
3489 0 == zap_contains(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
3490 DMU_POOL_OBSOLETE_BPOBJ));
3491 if (err == 0 && bpobj_is_open(&dp->dp_obsolete_bpobj)) {
3492 ASSERT(spa_feature_is_active(dp->dp_spa,
3493 SPA_FEATURE_OBSOLETE_COUNTS));
3495 scn->scn_is_bptree = B_FALSE;
3496 scn->scn_async_block_min_time_ms = zfs_obsolete_min_time_ms;
3497 err = bpobj_iterate(&dp->dp_obsolete_bpobj,
3498 dsl_scan_obsolete_block_cb, scn, tx);
3499 if (err != 0 && err != ERESTART)
3500 zfs_panic_recover("error %u from bpobj_iterate()", err);
3502 if (bpobj_is_empty(&dp->dp_obsolete_bpobj))
3503 dsl_pool_destroy_obsolete_bpobj(dp, tx);
3509 * This is the primary entry point for scans that is called from syncing
3510 * context. Scans must happen entirely during syncing context so that we
3511 * can guarantee that blocks we are currently scanning will not change out
3512 * from under us. While a scan is active, this function controls how quickly
3513 * transaction groups proceed, instead of the normal handling provided by
3514 * txg_sync_thread().
3517 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
3520 dsl_scan_t *scn = dp->dp_scan;
3521 spa_t *spa = dp->dp_spa;
3522 state_sync_type_t sync_type = SYNC_OPTIONAL;
3524 if (spa->spa_resilver_deferred &&
3525 !spa_feature_is_active(dp->dp_spa, SPA_FEATURE_RESILVER_DEFER))
3526 spa_feature_incr(spa, SPA_FEATURE_RESILVER_DEFER, tx);
3529 * Check for scn_restart_txg before checking spa_load_state, so
3530 * that we can restart an old-style scan while the pool is being
3531 * imported (see dsl_scan_init). We also restart scans if there
3532 * is a deferred resilver and the user has manually disabled
3533 * deferred resilvers via the tunable.
3535 if (dsl_scan_restarting(scn, tx) ||
3536 (spa->spa_resilver_deferred && zfs_resilver_disable_defer)) {
3537 pool_scan_func_t func = POOL_SCAN_SCRUB;
3538 dsl_scan_done(scn, B_FALSE, tx);
3539 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
3540 func = POOL_SCAN_RESILVER;
3541 zfs_dbgmsg("restarting scan func=%u on %s txg=%llu",
3542 func, dp->dp_spa->spa_name, (longlong_t)tx->tx_txg);
3543 dsl_scan_setup_sync(&func, tx);
3547 * Only process scans in sync pass 1.
3549 if (spa_sync_pass(spa) > 1)
3553 * If the spa is shutting down, then stop scanning. This will
3554 * ensure that the scan does not dirty any new data during the
3557 if (spa_shutting_down(spa))
3561 * If the scan is inactive due to a stalled async destroy, try again.
3563 if (!scn->scn_async_stalled && !dsl_scan_active(scn))
3566 /* reset scan statistics */
3567 scn->scn_visited_this_txg = 0;
3568 scn->scn_dedup_frees_this_txg = 0;
3569 scn->scn_holes_this_txg = 0;
3570 scn->scn_lt_min_this_txg = 0;
3571 scn->scn_gt_max_this_txg = 0;
3572 scn->scn_ddt_contained_this_txg = 0;
3573 scn->scn_objsets_visited_this_txg = 0;
3574 scn->scn_avg_seg_size_this_txg = 0;
3575 scn->scn_segs_this_txg = 0;
3576 scn->scn_avg_zio_size_this_txg = 0;
3577 scn->scn_zios_this_txg = 0;
3578 scn->scn_suspending = B_FALSE;
3579 scn->scn_sync_start_time = gethrtime();
3580 spa->spa_scrub_active = B_TRUE;
3583 * First process the async destroys. If we suspend, don't do
3584 * any scrubbing or resilvering. This ensures that there are no
3585 * async destroys while we are scanning, so the scan code doesn't
3586 * have to worry about traversing it. It is also faster to free the
3587 * blocks than to scrub them.
3589 err = dsl_process_async_destroys(dp, tx);
3593 if (!dsl_scan_is_running(scn) || dsl_scan_is_paused_scrub(scn))
3597 * Wait a few txgs after importing to begin scanning so that
3598 * we can get the pool imported quickly.
3600 if (spa->spa_syncing_txg < spa->spa_first_txg + SCAN_IMPORT_WAIT_TXGS)
3604 * zfs_scan_suspend_progress can be set to disable scan progress.
3605 * We don't want to spin the txg_sync thread, so we add a delay
3606 * here to simulate the time spent doing a scan. This is mostly
3607 * useful for testing and debugging.
3609 if (zfs_scan_suspend_progress) {
3610 uint64_t scan_time_ns = gethrtime() - scn->scn_sync_start_time;
3611 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
3612 zfs_resilver_min_time_ms : zfs_scrub_min_time_ms;
3614 while (zfs_scan_suspend_progress &&
3615 !txg_sync_waiting(scn->scn_dp) &&
3616 !spa_shutting_down(scn->scn_dp->dp_spa) &&
3617 NSEC2MSEC(scan_time_ns) < mintime) {
3619 scan_time_ns = gethrtime() - scn->scn_sync_start_time;
3625 * It is possible to switch from unsorted to sorted at any time,
3626 * but afterwards the scan will remain sorted unless reloaded from
3627 * a checkpoint after a reboot.
3629 if (!zfs_scan_legacy) {
3630 scn->scn_is_sorted = B_TRUE;
3631 if (scn->scn_last_checkpoint == 0)
3632 scn->scn_last_checkpoint = ddi_get_lbolt();
3636 * For sorted scans, determine what kind of work we will be doing
3637 * this txg based on our memory limitations and whether or not we
3638 * need to perform a checkpoint.
3640 if (scn->scn_is_sorted) {
3642 * If we are over our checkpoint interval, set scn_clearing
3643 * so that we can begin checkpointing immediately. The
3644 * checkpoint allows us to save a consistent bookmark
3645 * representing how much data we have scrubbed so far.
3646 * Otherwise, use the memory limit to determine if we should
3647 * scan for metadata or start issue scrub IOs. We accumulate
3648 * metadata until we hit our hard memory limit at which point
3649 * we issue scrub IOs until we are at our soft memory limit.
3651 if (scn->scn_checkpointing ||
3652 ddi_get_lbolt() - scn->scn_last_checkpoint >
3653 SEC_TO_TICK(zfs_scan_checkpoint_intval)) {
3654 if (!scn->scn_checkpointing)
3655 zfs_dbgmsg("begin scan checkpoint for %s",
3658 scn->scn_checkpointing = B_TRUE;
3659 scn->scn_clearing = B_TRUE;
3661 boolean_t should_clear = dsl_scan_should_clear(scn);
3662 if (should_clear && !scn->scn_clearing) {
3663 zfs_dbgmsg("begin scan clearing for %s",
3665 scn->scn_clearing = B_TRUE;
3666 } else if (!should_clear && scn->scn_clearing) {
3667 zfs_dbgmsg("finish scan clearing for %s",
3669 scn->scn_clearing = B_FALSE;
3673 ASSERT0(scn->scn_checkpointing);
3674 ASSERT0(scn->scn_clearing);
3677 if (!scn->scn_clearing && scn->scn_done_txg == 0) {
3678 /* Need to scan metadata for more blocks to scrub */
3679 dsl_scan_phys_t *scnp = &scn->scn_phys;
3680 taskqid_t prefetch_tqid;
3683 * Recalculate the max number of in-flight bytes for pool-wide
3684 * scanning operations (minimum 1MB). Limits for the issuing
3685 * phase are done per top-level vdev and are handled separately.
3687 scn->scn_maxinflight_bytes = MAX(zfs_scan_vdev_limit *
3688 dsl_scan_count_data_disks(spa->spa_root_vdev), 1ULL << 20);
3690 if (scnp->scn_ddt_bookmark.ddb_class <=
3691 scnp->scn_ddt_class_max) {
3692 ASSERT(ZB_IS_ZERO(&scnp->scn_bookmark));
3693 zfs_dbgmsg("doing scan sync for %s txg %llu; "
3694 "ddt bm=%llu/%llu/%llu/%llx",
3696 (longlong_t)tx->tx_txg,
3697 (longlong_t)scnp->scn_ddt_bookmark.ddb_class,
3698 (longlong_t)scnp->scn_ddt_bookmark.ddb_type,
3699 (longlong_t)scnp->scn_ddt_bookmark.ddb_checksum,
3700 (longlong_t)scnp->scn_ddt_bookmark.ddb_cursor);
3702 zfs_dbgmsg("doing scan sync for %s txg %llu; "
3703 "bm=%llu/%llu/%llu/%llu",
3705 (longlong_t)tx->tx_txg,
3706 (longlong_t)scnp->scn_bookmark.zb_objset,
3707 (longlong_t)scnp->scn_bookmark.zb_object,
3708 (longlong_t)scnp->scn_bookmark.zb_level,
3709 (longlong_t)scnp->scn_bookmark.zb_blkid);
3712 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
3713 NULL, ZIO_FLAG_CANFAIL);
3715 scn->scn_prefetch_stop = B_FALSE;
3716 prefetch_tqid = taskq_dispatch(dp->dp_sync_taskq,
3717 dsl_scan_prefetch_thread, scn, TQ_SLEEP);
3718 ASSERT(prefetch_tqid != TASKQID_INVALID);
3720 dsl_pool_config_enter(dp, FTAG);
3721 dsl_scan_visit(scn, tx);
3722 dsl_pool_config_exit(dp, FTAG);
3724 mutex_enter(&dp->dp_spa->spa_scrub_lock);
3725 scn->scn_prefetch_stop = B_TRUE;
3726 cv_broadcast(&spa->spa_scrub_io_cv);
3727 mutex_exit(&dp->dp_spa->spa_scrub_lock);
3729 taskq_wait_id(dp->dp_sync_taskq, prefetch_tqid);
3730 (void) zio_wait(scn->scn_zio_root);
3731 scn->scn_zio_root = NULL;
3733 zfs_dbgmsg("scan visited %llu blocks of %s in %llums "
3734 "(%llu os's, %llu holes, %llu < mintxg, "
3735 "%llu in ddt, %llu > maxtxg)",
3736 (longlong_t)scn->scn_visited_this_txg,
3738 (longlong_t)NSEC2MSEC(gethrtime() -
3739 scn->scn_sync_start_time),
3740 (longlong_t)scn->scn_objsets_visited_this_txg,
3741 (longlong_t)scn->scn_holes_this_txg,
3742 (longlong_t)scn->scn_lt_min_this_txg,
3743 (longlong_t)scn->scn_ddt_contained_this_txg,
3744 (longlong_t)scn->scn_gt_max_this_txg);
3746 if (!scn->scn_suspending) {
3747 ASSERT0(avl_numnodes(&scn->scn_queue));
3748 scn->scn_done_txg = tx->tx_txg + 1;
3749 if (scn->scn_is_sorted) {
3750 scn->scn_checkpointing = B_TRUE;
3751 scn->scn_clearing = B_TRUE;
3753 zfs_dbgmsg("scan complete for %s txg %llu",
3755 (longlong_t)tx->tx_txg);
3757 } else if (scn->scn_is_sorted && scn->scn_bytes_pending != 0) {
3758 ASSERT(scn->scn_clearing);
3760 /* need to issue scrubbing IOs from per-vdev queues */
3761 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
3762 NULL, ZIO_FLAG_CANFAIL);
3763 scan_io_queues_run(scn);
3764 (void) zio_wait(scn->scn_zio_root);
3765 scn->scn_zio_root = NULL;
3767 /* calculate and dprintf the current memory usage */
3768 (void) dsl_scan_should_clear(scn);
3769 dsl_scan_update_stats(scn);
3771 zfs_dbgmsg("scan issued %llu blocks for %s (%llu segs) "
3772 "in %llums (avg_block_size = %llu, avg_seg_size = %llu)",
3773 (longlong_t)scn->scn_zios_this_txg,
3775 (longlong_t)scn->scn_segs_this_txg,
3776 (longlong_t)NSEC2MSEC(gethrtime() -
3777 scn->scn_sync_start_time),
3778 (longlong_t)scn->scn_avg_zio_size_this_txg,
3779 (longlong_t)scn->scn_avg_seg_size_this_txg);
3780 } else if (scn->scn_done_txg != 0 && scn->scn_done_txg <= tx->tx_txg) {
3781 /* Finished with everything. Mark the scrub as complete */
3782 zfs_dbgmsg("scan issuing complete txg %llu for %s",
3783 (longlong_t)tx->tx_txg,
3785 ASSERT3U(scn->scn_done_txg, !=, 0);
3786 ASSERT0(spa->spa_scrub_inflight);
3787 ASSERT0(scn->scn_bytes_pending);
3788 dsl_scan_done(scn, B_TRUE, tx);
3789 sync_type = SYNC_MANDATORY;
3792 dsl_scan_sync_state(scn, tx, sync_type);
3796 count_block(dsl_scan_t *scn, zfs_all_blkstats_t *zab, const blkptr_t *bp)
3801 * Don't count embedded bp's, since we already did the work of
3802 * scanning these when we scanned the containing block.
3804 if (BP_IS_EMBEDDED(bp))
3808 * Update the spa's stats on how many bytes we have issued.
3809 * Sequential scrubs create a zio for each DVA of the bp. Each
3810 * of these will include all DVAs for repair purposes, but the
3811 * zio code will only try the first one unless there is an issue.
3812 * Therefore, we should only count the first DVA for these IOs.
3814 if (scn->scn_is_sorted) {
3815 atomic_add_64(&scn->scn_dp->dp_spa->spa_scan_pass_issued,
3816 DVA_GET_ASIZE(&bp->blk_dva[0]));
3818 spa_t *spa = scn->scn_dp->dp_spa;
3820 for (i = 0; i < BP_GET_NDVAS(bp); i++) {
3821 atomic_add_64(&spa->spa_scan_pass_issued,
3822 DVA_GET_ASIZE(&bp->blk_dva[i]));
3827 * If we resume after a reboot, zab will be NULL; don't record
3828 * incomplete stats in that case.
3833 mutex_enter(&zab->zab_lock);
3835 for (i = 0; i < 4; i++) {
3836 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
3837 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
3839 if (t & DMU_OT_NEWTYPE)
3841 zfs_blkstat_t *zb = &zab->zab_type[l][t];
3845 zb->zb_asize += BP_GET_ASIZE(bp);
3846 zb->zb_lsize += BP_GET_LSIZE(bp);
3847 zb->zb_psize += BP_GET_PSIZE(bp);
3848 zb->zb_gangs += BP_COUNT_GANG(bp);
3850 switch (BP_GET_NDVAS(bp)) {
3852 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
3853 DVA_GET_VDEV(&bp->blk_dva[1]))
3854 zb->zb_ditto_2_of_2_samevdev++;
3857 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
3858 DVA_GET_VDEV(&bp->blk_dva[1])) +
3859 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
3860 DVA_GET_VDEV(&bp->blk_dva[2])) +
3861 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
3862 DVA_GET_VDEV(&bp->blk_dva[2]));
3864 zb->zb_ditto_2_of_3_samevdev++;
3865 else if (equal == 3)
3866 zb->zb_ditto_3_of_3_samevdev++;
3871 mutex_exit(&zab->zab_lock);
3875 scan_io_queue_insert_impl(dsl_scan_io_queue_t *queue, scan_io_t *sio)
3878 int64_t asize = SIO_GET_ASIZE(sio);
3879 dsl_scan_t *scn = queue->q_scn;
3881 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
3883 if (avl_find(&queue->q_sios_by_addr, sio, &idx) != NULL) {
3884 /* block is already scheduled for reading */
3885 atomic_add_64(&scn->scn_bytes_pending, -asize);
3889 avl_insert(&queue->q_sios_by_addr, sio, idx);
3890 queue->q_sio_memused += SIO_GET_MUSED(sio);
3891 range_tree_add(queue->q_exts_by_addr, SIO_GET_OFFSET(sio), asize);
3895 * Given all the info we got from our metadata scanning process, we
3896 * construct a scan_io_t and insert it into the scan sorting queue. The
3897 * I/O must already be suitable for us to process. This is controlled
3898 * by dsl_scan_enqueue().
3901 scan_io_queue_insert(dsl_scan_io_queue_t *queue, const blkptr_t *bp, int dva_i,
3902 int zio_flags, const zbookmark_phys_t *zb)
3904 dsl_scan_t *scn = queue->q_scn;
3905 scan_io_t *sio = sio_alloc(BP_GET_NDVAS(bp));
3907 ASSERT0(BP_IS_GANG(bp));
3908 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
3910 bp2sio(bp, sio, dva_i);
3911 sio->sio_flags = zio_flags;
3915 * Increment the bytes pending counter now so that we can't
3916 * get an integer underflow in case the worker processes the
3917 * zio before we get to incrementing this counter.
3919 atomic_add_64(&scn->scn_bytes_pending, SIO_GET_ASIZE(sio));
3921 scan_io_queue_insert_impl(queue, sio);
3925 * Given a set of I/O parameters as discovered by the metadata traversal
3926 * process, attempts to place the I/O into the sorted queues (if allowed),
3927 * or immediately executes the I/O.
3930 dsl_scan_enqueue(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
3931 const zbookmark_phys_t *zb)
3933 spa_t *spa = dp->dp_spa;
3935 ASSERT(!BP_IS_EMBEDDED(bp));
3938 * Gang blocks are hard to issue sequentially, so we just issue them
3939 * here immediately instead of queuing them.
3941 if (!dp->dp_scan->scn_is_sorted || BP_IS_GANG(bp)) {
3942 scan_exec_io(dp, bp, zio_flags, zb, NULL);
3946 for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
3950 dva = bp->blk_dva[i];
3951 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&dva));
3952 ASSERT(vdev != NULL);
3954 mutex_enter(&vdev->vdev_scan_io_queue_lock);
3955 if (vdev->vdev_scan_io_queue == NULL)
3956 vdev->vdev_scan_io_queue = scan_io_queue_create(vdev);
3957 ASSERT(dp->dp_scan != NULL);
3958 scan_io_queue_insert(vdev->vdev_scan_io_queue, bp,
3960 mutex_exit(&vdev->vdev_scan_io_queue_lock);
3965 dsl_scan_scrub_cb(dsl_pool_t *dp,
3966 const blkptr_t *bp, const zbookmark_phys_t *zb)
3968 dsl_scan_t *scn = dp->dp_scan;
3969 spa_t *spa = dp->dp_spa;
3970 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
3971 size_t psize = BP_GET_PSIZE(bp);
3972 boolean_t needs_io = B_FALSE;
3973 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
3976 if (phys_birth <= scn->scn_phys.scn_min_txg ||
3977 phys_birth >= scn->scn_phys.scn_max_txg) {
3978 count_block(scn, dp->dp_blkstats, bp);
3982 /* Embedded BP's have phys_birth==0, so we reject them above. */
3983 ASSERT(!BP_IS_EMBEDDED(bp));
3985 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
3986 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
3987 zio_flags |= ZIO_FLAG_SCRUB;
3990 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
3991 zio_flags |= ZIO_FLAG_RESILVER;
3995 /* If it's an intent log block, failure is expected. */
3996 if (zb->zb_level == ZB_ZIL_LEVEL)
3997 zio_flags |= ZIO_FLAG_SPECULATIVE;
3999 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
4000 const dva_t *dva = &bp->blk_dva[d];
4003 * Keep track of how much data we've examined so that
4004 * zpool(8) status can make useful progress reports.
4006 scn->scn_phys.scn_examined += DVA_GET_ASIZE(dva);
4007 spa->spa_scan_pass_exam += DVA_GET_ASIZE(dva);
4009 /* if it's a resilver, this may not be in the target range */
4011 needs_io = dsl_scan_need_resilver(spa, dva, psize,
4015 if (needs_io && !zfs_no_scrub_io) {
4016 dsl_scan_enqueue(dp, bp, zio_flags, zb);
4018 count_block(scn, dp->dp_blkstats, bp);
4021 /* do not relocate this block */
4026 dsl_scan_scrub_done(zio_t *zio)
4028 spa_t *spa = zio->io_spa;
4029 blkptr_t *bp = zio->io_bp;
4030 dsl_scan_io_queue_t *queue = zio->io_private;
4032 abd_free(zio->io_abd);
4034 if (queue == NULL) {
4035 mutex_enter(&spa->spa_scrub_lock);
4036 ASSERT3U(spa->spa_scrub_inflight, >=, BP_GET_PSIZE(bp));
4037 spa->spa_scrub_inflight -= BP_GET_PSIZE(bp);
4038 cv_broadcast(&spa->spa_scrub_io_cv);
4039 mutex_exit(&spa->spa_scrub_lock);
4041 mutex_enter(&queue->q_vd->vdev_scan_io_queue_lock);
4042 ASSERT3U(queue->q_inflight_bytes, >=, BP_GET_PSIZE(bp));
4043 queue->q_inflight_bytes -= BP_GET_PSIZE(bp);
4044 cv_broadcast(&queue->q_zio_cv);
4045 mutex_exit(&queue->q_vd->vdev_scan_io_queue_lock);
4048 if (zio->io_error && (zio->io_error != ECKSUM ||
4049 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
4050 atomic_inc_64(&spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors);
4055 * Given a scanning zio's information, executes the zio. The zio need
4056 * not necessarily be only sortable, this function simply executes the
4057 * zio, no matter what it is. The optional queue argument allows the
4058 * caller to specify that they want per top level vdev IO rate limiting
4059 * instead of the legacy global limiting.
4062 scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
4063 const zbookmark_phys_t *zb, dsl_scan_io_queue_t *queue)
4065 spa_t *spa = dp->dp_spa;
4066 dsl_scan_t *scn = dp->dp_scan;
4067 size_t size = BP_GET_PSIZE(bp);
4068 abd_t *data = abd_alloc_for_io(size, B_FALSE);
4070 if (queue == NULL) {
4071 ASSERT3U(scn->scn_maxinflight_bytes, >, 0);
4072 mutex_enter(&spa->spa_scrub_lock);
4073 while (spa->spa_scrub_inflight >= scn->scn_maxinflight_bytes)
4074 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
4075 spa->spa_scrub_inflight += BP_GET_PSIZE(bp);
4076 mutex_exit(&spa->spa_scrub_lock);
4078 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock;
4080 ASSERT3U(queue->q_maxinflight_bytes, >, 0);
4081 mutex_enter(q_lock);
4082 while (queue->q_inflight_bytes >= queue->q_maxinflight_bytes)
4083 cv_wait(&queue->q_zio_cv, q_lock);
4084 queue->q_inflight_bytes += BP_GET_PSIZE(bp);
4088 count_block(scn, dp->dp_blkstats, bp);
4089 zio_nowait(zio_read(scn->scn_zio_root, spa, bp, data, size,
4090 dsl_scan_scrub_done, queue, ZIO_PRIORITY_SCRUB, zio_flags, zb));
4094 * This is the primary extent sorting algorithm. We balance two parameters:
4095 * 1) how many bytes of I/O are in an extent
4096 * 2) how well the extent is filled with I/O (as a fraction of its total size)
4097 * Since we allow extents to have gaps between their constituent I/Os, it's
4098 * possible to have a fairly large extent that contains the same amount of
4099 * I/O bytes than a much smaller extent, which just packs the I/O more tightly.
4100 * The algorithm sorts based on a score calculated from the extent's size,
4101 * the relative fill volume (in %) and a "fill weight" parameter that controls
4102 * the split between whether we prefer larger extents or more well populated
4105 * SCORE = FILL_IN_BYTES + (FILL_IN_PERCENT * FILL_IN_BYTES * FILL_WEIGHT)
4108 * 1) assume extsz = 64 MiB
4109 * 2) assume fill = 32 MiB (extent is half full)
4110 * 3) assume fill_weight = 3
4111 * 4) SCORE = 32M + (((32M * 100) / 64M) * 3 * 32M) / 100
4112 * SCORE = 32M + (50 * 3 * 32M) / 100
4113 * SCORE = 32M + (4800M / 100)
4116 * | +--- final total relative fill-based score
4117 * +--------- final total fill-based score
4120 * As can be seen, at fill_ratio=3, the algorithm is slightly biased towards
4121 * extents that are more completely filled (in a 3:2 ratio) vs just larger.
4122 * Note that as an optimization, we replace multiplication and division by
4123 * 100 with bitshifting by 7 (which effectively multiplies and divides by 128).
4126 ext_size_compare(const void *x, const void *y)
4128 const range_seg_gap_t *rsa = x, *rsb = y;
4130 uint64_t sa = rsa->rs_end - rsa->rs_start;
4131 uint64_t sb = rsb->rs_end - rsb->rs_start;
4132 uint64_t score_a, score_b;
4134 score_a = rsa->rs_fill + ((((rsa->rs_fill << 7) / sa) *
4135 fill_weight * rsa->rs_fill) >> 7);
4136 score_b = rsb->rs_fill + ((((rsb->rs_fill << 7) / sb) *
4137 fill_weight * rsb->rs_fill) >> 7);
4139 if (score_a > score_b)
4141 if (score_a == score_b) {
4142 if (rsa->rs_start < rsb->rs_start)
4144 if (rsa->rs_start == rsb->rs_start)
4152 * Comparator for the q_sios_by_addr tree. Sorting is simply performed
4153 * based on LBA-order (from lowest to highest).
4156 sio_addr_compare(const void *x, const void *y)
4158 const scan_io_t *a = x, *b = y;
4160 return (TREE_CMP(SIO_GET_OFFSET(a), SIO_GET_OFFSET(b)));
4163 /* IO queues are created on demand when they are needed. */
4164 static dsl_scan_io_queue_t *
4165 scan_io_queue_create(vdev_t *vd)
4167 dsl_scan_t *scn = vd->vdev_spa->spa_dsl_pool->dp_scan;
4168 dsl_scan_io_queue_t *q = kmem_zalloc(sizeof (*q), KM_SLEEP);
4172 q->q_sio_memused = 0;
4173 cv_init(&q->q_zio_cv, NULL, CV_DEFAULT, NULL);
4174 q->q_exts_by_addr = range_tree_create_impl(&rt_btree_ops, RANGE_SEG_GAP,
4175 &q->q_exts_by_size, 0, 0, ext_size_compare, zfs_scan_max_ext_gap);
4176 avl_create(&q->q_sios_by_addr, sio_addr_compare,
4177 sizeof (scan_io_t), offsetof(scan_io_t, sio_nodes.sio_addr_node));
4183 * Destroys a scan queue and all segments and scan_io_t's contained in it.
4184 * No further execution of I/O occurs, anything pending in the queue is
4185 * simply freed without being executed.
4188 dsl_scan_io_queue_destroy(dsl_scan_io_queue_t *queue)
4190 dsl_scan_t *scn = queue->q_scn;
4192 void *cookie = NULL;
4193 int64_t bytes_dequeued = 0;
4195 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
4197 while ((sio = avl_destroy_nodes(&queue->q_sios_by_addr, &cookie)) !=
4199 ASSERT(range_tree_contains(queue->q_exts_by_addr,
4200 SIO_GET_OFFSET(sio), SIO_GET_ASIZE(sio)));
4201 bytes_dequeued += SIO_GET_ASIZE(sio);
4202 queue->q_sio_memused -= SIO_GET_MUSED(sio);
4206 ASSERT0(queue->q_sio_memused);
4207 atomic_add_64(&scn->scn_bytes_pending, -bytes_dequeued);
4208 range_tree_vacate(queue->q_exts_by_addr, NULL, queue);
4209 range_tree_destroy(queue->q_exts_by_addr);
4210 avl_destroy(&queue->q_sios_by_addr);
4211 cv_destroy(&queue->q_zio_cv);
4213 kmem_free(queue, sizeof (*queue));
4217 * Properly transfers a dsl_scan_queue_t from `svd' to `tvd'. This is
4218 * called on behalf of vdev_top_transfer when creating or destroying
4219 * a mirror vdev due to zpool attach/detach.
4222 dsl_scan_io_queue_vdev_xfer(vdev_t *svd, vdev_t *tvd)
4224 mutex_enter(&svd->vdev_scan_io_queue_lock);
4225 mutex_enter(&tvd->vdev_scan_io_queue_lock);
4227 VERIFY3P(tvd->vdev_scan_io_queue, ==, NULL);
4228 tvd->vdev_scan_io_queue = svd->vdev_scan_io_queue;
4229 svd->vdev_scan_io_queue = NULL;
4230 if (tvd->vdev_scan_io_queue != NULL)
4231 tvd->vdev_scan_io_queue->q_vd = tvd;
4233 mutex_exit(&tvd->vdev_scan_io_queue_lock);
4234 mutex_exit(&svd->vdev_scan_io_queue_lock);
4238 scan_io_queues_destroy(dsl_scan_t *scn)
4240 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
4242 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
4243 vdev_t *tvd = rvd->vdev_child[i];
4245 mutex_enter(&tvd->vdev_scan_io_queue_lock);
4246 if (tvd->vdev_scan_io_queue != NULL)
4247 dsl_scan_io_queue_destroy(tvd->vdev_scan_io_queue);
4248 tvd->vdev_scan_io_queue = NULL;
4249 mutex_exit(&tvd->vdev_scan_io_queue_lock);
4254 dsl_scan_freed_dva(spa_t *spa, const blkptr_t *bp, int dva_i)
4256 dsl_pool_t *dp = spa->spa_dsl_pool;
4257 dsl_scan_t *scn = dp->dp_scan;
4260 dsl_scan_io_queue_t *queue;
4261 scan_io_t *srch_sio, *sio;
4263 uint64_t start, size;
4265 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[dva_i]));
4266 ASSERT(vdev != NULL);
4267 q_lock = &vdev->vdev_scan_io_queue_lock;
4268 queue = vdev->vdev_scan_io_queue;
4270 mutex_enter(q_lock);
4271 if (queue == NULL) {
4276 srch_sio = sio_alloc(BP_GET_NDVAS(bp));
4277 bp2sio(bp, srch_sio, dva_i);
4278 start = SIO_GET_OFFSET(srch_sio);
4279 size = SIO_GET_ASIZE(srch_sio);
4282 * We can find the zio in two states:
4283 * 1) Cold, just sitting in the queue of zio's to be issued at
4284 * some point in the future. In this case, all we do is
4285 * remove the zio from the q_sios_by_addr tree, decrement
4286 * its data volume from the containing range_seg_t and
4287 * resort the q_exts_by_size tree to reflect that the
4288 * range_seg_t has lost some of its 'fill'. We don't shorten
4289 * the range_seg_t - this is usually rare enough not to be
4290 * worth the extra hassle of trying keep track of precise
4291 * extent boundaries.
4292 * 2) Hot, where the zio is currently in-flight in
4293 * dsl_scan_issue_ios. In this case, we can't simply
4294 * reach in and stop the in-flight zio's, so we instead
4295 * block the caller. Eventually, dsl_scan_issue_ios will
4296 * be done with issuing the zio's it gathered and will
4299 sio = avl_find(&queue->q_sios_by_addr, srch_sio, &idx);
4303 int64_t asize = SIO_GET_ASIZE(sio);
4306 /* Got it while it was cold in the queue */
4307 ASSERT3U(start, ==, SIO_GET_OFFSET(sio));
4308 ASSERT3U(size, ==, asize);
4309 avl_remove(&queue->q_sios_by_addr, sio);
4310 queue->q_sio_memused -= SIO_GET_MUSED(sio);
4312 ASSERT(range_tree_contains(queue->q_exts_by_addr, start, size));
4313 range_tree_remove_fill(queue->q_exts_by_addr, start, size);
4316 * We only update scn_bytes_pending in the cold path,
4317 * otherwise it will already have been accounted for as
4318 * part of the zio's execution.
4320 atomic_add_64(&scn->scn_bytes_pending, -asize);
4322 /* count the block as though we issued it */
4323 sio2bp(sio, &tmpbp);
4324 count_block(scn, dp->dp_blkstats, &tmpbp);
4332 * Callback invoked when a zio_free() zio is executing. This needs to be
4333 * intercepted to prevent the zio from deallocating a particular portion
4334 * of disk space and it then getting reallocated and written to, while we
4335 * still have it queued up for processing.
4338 dsl_scan_freed(spa_t *spa, const blkptr_t *bp)
4340 dsl_pool_t *dp = spa->spa_dsl_pool;
4341 dsl_scan_t *scn = dp->dp_scan;
4343 ASSERT(!BP_IS_EMBEDDED(bp));
4344 ASSERT(scn != NULL);
4345 if (!dsl_scan_is_running(scn))
4348 for (int i = 0; i < BP_GET_NDVAS(bp); i++)
4349 dsl_scan_freed_dva(spa, bp, i);
4353 * Check if a vdev needs resilvering (non-empty DTL), if so, and resilver has
4354 * not started, start it. Otherwise, only restart if max txg in DTL range is
4355 * greater than the max txg in the current scan. If the DTL max is less than
4356 * the scan max, then the vdev has not missed any new data since the resilver
4357 * started, so a restart is not needed.
4360 dsl_scan_assess_vdev(dsl_pool_t *dp, vdev_t *vd)
4364 if (!vdev_resilver_needed(vd, &min, &max))
4367 if (!dsl_scan_resilvering(dp)) {
4368 spa_async_request(dp->dp_spa, SPA_ASYNC_RESILVER);
4372 if (max <= dp->dp_scan->scn_phys.scn_max_txg)
4375 /* restart is needed, check if it can be deferred */
4376 if (spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_RESILVER_DEFER))
4377 vdev_defer_resilver(vd);
4379 spa_async_request(dp->dp_spa, SPA_ASYNC_RESILVER);
4383 ZFS_MODULE_PARAM(zfs, zfs_, scan_vdev_limit, ULONG, ZMOD_RW,
4384 "Max bytes in flight per leaf vdev for scrubs and resilvers");
4386 ZFS_MODULE_PARAM(zfs, zfs_, scrub_min_time_ms, INT, ZMOD_RW,
4387 "Min millisecs to scrub per txg");
4389 ZFS_MODULE_PARAM(zfs, zfs_, obsolete_min_time_ms, INT, ZMOD_RW,
4390 "Min millisecs to obsolete per txg");
4392 ZFS_MODULE_PARAM(zfs, zfs_, free_min_time_ms, INT, ZMOD_RW,
4393 "Min millisecs to free per txg");
4395 ZFS_MODULE_PARAM(zfs, zfs_, resilver_min_time_ms, INT, ZMOD_RW,
4396 "Min millisecs to resilver per txg");
4398 ZFS_MODULE_PARAM(zfs, zfs_, scan_suspend_progress, INT, ZMOD_RW,
4399 "Set to prevent scans from progressing");
4401 ZFS_MODULE_PARAM(zfs, zfs_, no_scrub_io, INT, ZMOD_RW,
4402 "Set to disable scrub I/O");
4404 ZFS_MODULE_PARAM(zfs, zfs_, no_scrub_prefetch, INT, ZMOD_RW,
4405 "Set to disable scrub prefetching");
4407 ZFS_MODULE_PARAM(zfs, zfs_, async_block_max_blocks, ULONG, ZMOD_RW,
4408 "Max number of blocks freed in one txg");
4410 ZFS_MODULE_PARAM(zfs, zfs_, max_async_dedup_frees, ULONG, ZMOD_RW,
4411 "Max number of dedup blocks freed in one txg");
4413 ZFS_MODULE_PARAM(zfs, zfs_, free_bpobj_enabled, INT, ZMOD_RW,
4414 "Enable processing of the free_bpobj");
4416 ZFS_MODULE_PARAM(zfs, zfs_, scan_mem_lim_fact, INT, ZMOD_RW,
4417 "Fraction of RAM for scan hard limit");
4419 ZFS_MODULE_PARAM(zfs, zfs_, scan_issue_strategy, INT, ZMOD_RW,
4420 "IO issuing strategy during scrubbing. "
4421 "0 = default, 1 = LBA, 2 = size");
4423 ZFS_MODULE_PARAM(zfs, zfs_, scan_legacy, INT, ZMOD_RW,
4424 "Scrub using legacy non-sequential method");
4426 ZFS_MODULE_PARAM(zfs, zfs_, scan_checkpoint_intval, INT, ZMOD_RW,
4427 "Scan progress on-disk checkpointing interval");
4429 ZFS_MODULE_PARAM(zfs, zfs_, scan_max_ext_gap, ULONG, ZMOD_RW,
4430 "Max gap in bytes between sequential scrub / resilver I/Os");
4432 ZFS_MODULE_PARAM(zfs, zfs_, scan_mem_lim_soft_fact, INT, ZMOD_RW,
4433 "Fraction of hard limit used as soft limit");
4435 ZFS_MODULE_PARAM(zfs, zfs_, scan_strict_mem_lim, INT, ZMOD_RW,
4436 "Tunable to attempt to reduce lock contention");
4438 ZFS_MODULE_PARAM(zfs, zfs_, scan_fill_weight, INT, ZMOD_RW,
4439 "Tunable to adjust bias towards more filled segments during scans");
4441 ZFS_MODULE_PARAM(zfs, zfs_, resilver_disable_defer, INT, ZMOD_RW,
4442 "Process all resilvers immediately");