1 /*
2 * CDDL HEADER START
3 *
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.
7 *
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.
12 *
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]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Delphix. All rights reserved.
24 */
25
26 #include <sys/dsl_scan.h>
27 #include <sys/dsl_pool.h>
28 #include <sys/dsl_dataset.h>
29 #include <sys/dsl_prop.h>
30 #include <sys/dsl_dir.h>
31 #include <sys/dsl_synctask.h>
32 #include <sys/dnode.h>
33 #include <sys/dmu_tx.h>
34 #include <sys/dmu_objset.h>
35 #include <sys/arc.h>
36 #include <sys/zap.h>
37 #include <sys/zio.h>
38 #include <sys/zfs_context.h>
39 #include <sys/fs/zfs.h>
40 #include <sys/zfs_znode.h>
41 #include <sys/spa_impl.h>
42 #include <sys/vdev_impl.h>
43 #include <sys/zil_impl.h>
44 #include <sys/zio_checksum.h>
45 #include <sys/ddt.h>
46 #include <sys/sa.h>
47 #include <sys/sa_impl.h>
48 #include <sys/zfeature.h>
49 #ifdef _KERNEL
50 #include <sys/zfs_vfsops.h>
51 #endif
52
53 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *, const zbookmark_t *);
54
55 static scan_cb_t dsl_scan_defrag_cb;
56 static scan_cb_t dsl_scan_scrub_cb;
57 static scan_cb_t dsl_scan_remove_cb;
58 static void dsl_scan_cancel_sync(void *, dmu_tx_t *);
59 static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *tx);
60
61 int zfs_top_maxinflight = 32; /* maximum I/Os per top-level */
62 int zfs_resilver_delay = 2; /* number of ticks to delay resilver */
63 int zfs_scrub_delay = 4; /* number of ticks to delay scrub */
64 int zfs_scan_idle = 50; /* idle window in clock ticks */
65
66 int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
67 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
68 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
69 boolean_t zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
70 boolean_t zfs_no_scrub_prefetch = B_FALSE; /* set to disable srub prefetching */
71 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
72 int dsl_scan_delay_completion = B_FALSE; /* set to delay scan completion */
73
74 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
75 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
76 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
77
78 extern int zfs_txg_timeout;
79
80 /* the order has to match pool_scan_type */
81 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
82 NULL,
83 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
84 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
85 };
86
87 int
88 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
89 {
90 int err;
91 dsl_scan_t *scn;
92 spa_t *spa = dp->dp_spa;
93 uint64_t f;
94
95 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
96 scn->scn_dp = dp;
97
98 /*
99 * It's possible that we're resuming a scan after a reboot so
100 * make sure that the scan_async_destroying flag is initialized
101 * appropriately.
102 */
103 ASSERT(!scn->scn_async_destroying);
104 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
105 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY]);
106
107 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
108 "scrub_func", sizeof (uint64_t), 1, &f);
109 if (err == 0) {
110 /*
111 * There was an old-style scrub in progress. Restart a
112 * new-style scrub from the beginning.
113 */
114 scn->scn_restart_txg = txg;
115 zfs_dbgmsg("old-style scrub was in progress; "
116 "restarting new-style scrub in txg %llu",
117 scn->scn_restart_txg);
118
119 /*
120 * Load the queue obj from the old location so that it
121 * can be freed by dsl_scan_done().
122 */
123 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
124 "scrub_queue", sizeof (uint64_t), 1,
125 &scn->scn_phys.scn_queue_obj);
126 } else {
127 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
128 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
129 &scn->scn_phys);
130 if (err == ENOENT)
131 return (0);
132 else if (err)
133 return (err);
134
135 if (scn->scn_phys.scn_state == DSS_SCANNING &&
136 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
137 /*
138 * A new-type scrub was in progress on an old
139 * pool, and the pool was accessed by old
140 * software. Restart from the beginning, since
141 * the old software may have changed the pool in
142 * the meantime.
143 */
144 scn->scn_restart_txg = txg;
145 zfs_dbgmsg("new-style scrub was modified "
146 "by old software; restarting in txg %llu",
147 scn->scn_restart_txg);
148 }
149 }
150
151 spa_scan_stat_init(spa);
152 return (0);
153 }
154
155 void
156 dsl_scan_fini(dsl_pool_t *dp)
157 {
158 if (dp->dp_scan) {
159 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
160 dp->dp_scan = NULL;
161 }
162 }
163
164 /* ARGSUSED */
165 static int
166 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
167 {
168 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
169
170 if (scn->scn_phys.scn_state == DSS_SCANNING)
171 return (SET_ERROR(EBUSY));
172
173 return (0);
174 }
175
176 static void
177 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
178 {
179 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
180 pool_scan_func_t *funcp = arg;
181 dmu_object_type_t ot = 0;
182 dsl_pool_t *dp = scn->scn_dp;
183 spa_t *spa = dp->dp_spa;
184
185 ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
186 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
187 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
188 scn->scn_phys.scn_func = *funcp;
189 scn->scn_phys.scn_state = DSS_SCANNING;
190 scn->scn_phys.scn_min_txg = 0;
191 scn->scn_phys.scn_max_txg = tx->tx_txg;
192 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
193 scn->scn_phys.scn_start_time = gethrestime_sec();
194 scn->scn_phys.scn_errors = 0;
195 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
196 scn->scn_restart_txg = 0;
197 scn->scn_done_txg = 0;
198 spa_scan_stat_init(spa);
199
200 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
201 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
202
203 /* rewrite all disk labels */
204 vdev_config_dirty(spa->spa_root_vdev);
205
206 if (vdev_resilver_needed(spa->spa_root_vdev,
207 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
208 spa_event_notify(spa, NULL, ESC_ZFS_RESILVER_START);
209 } else {
210 spa_event_notify(spa, NULL, ESC_ZFS_SCRUB_START);
211 }
212
213 spa->spa_scrub_started = B_TRUE;
214 /*
215 * If this is an incremental scrub, limit the DDT scrub phase
216 * to just the auto-ditto class (for correctness); the rest
217 * of the scrub should go faster using top-down pruning.
218 */
219 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
220 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
221
222 }
223
224 /* back to the generic stuff */
225
226 if (dp->dp_blkstats == NULL) {
227 dp->dp_blkstats =
228 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
229 }
230 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
231
232 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
233 ot = DMU_OT_ZAP_OTHER;
234
235 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
236 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
237
238 dsl_scan_sync_state(scn, tx);
239
240 spa_history_log_internal(spa, "scan setup", tx,
241 "func=%u mintxg=%llu maxtxg=%llu",
242 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
243 }
244
245 /* ARGSUSED */
246 static void
247 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
248 {
249 static const char *old_names[] = {
250 "scrub_bookmark",
251 "scrub_ddt_bookmark",
252 "scrub_ddt_class_max",
253 "scrub_queue",
254 "scrub_min_txg",
255 "scrub_max_txg",
256 "scrub_func",
257 "scrub_errors",
258 NULL
259 };
260
261 dsl_pool_t *dp = scn->scn_dp;
262 spa_t *spa = dp->dp_spa;
263 int i;
264
265 /* Remove any remnants of an old-style scrub. */
266 for (i = 0; old_names[i]; i++) {
267 (void) zap_remove(dp->dp_meta_objset,
268 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
269 }
270
271 if (scn->scn_phys.scn_queue_obj != 0) {
272 VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
273 scn->scn_phys.scn_queue_obj, tx));
274 scn->scn_phys.scn_queue_obj = 0;
275 }
276
277 /*
278 * If we were "restarted" from a stopped state, don't bother
279 * with anything else.
280 */
281 if (scn->scn_phys.scn_state != DSS_SCANNING)
282 return;
283
284 if (complete)
285 scn->scn_phys.scn_state = DSS_FINISHED;
286 else
287 scn->scn_phys.scn_state = DSS_CANCELED;
288
289 spa_history_log_internal(spa, "scan done", tx,
290 "complete=%u", complete);
291
292 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
293 mutex_enter(&spa->spa_scrub_lock);
294 while (spa->spa_scrub_inflight > 0) {
295 cv_wait(&spa->spa_scrub_io_cv,
296 &spa->spa_scrub_lock);
297 }
298 mutex_exit(&spa->spa_scrub_lock);
299 spa->spa_scrub_started = B_FALSE;
300 spa->spa_scrub_active = B_FALSE;
301
302 /*
303 * If the scrub/resilver completed, update all DTLs to
304 * reflect this. Whether it succeeded or not, vacate
305 * all temporary scrub DTLs.
306 */
307 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
308 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
309 if (complete) {
310 spa_event_notify(spa, NULL, scn->scn_phys.scn_min_txg ?
311 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
312 }
313 spa_errlog_rotate(spa);
314
315 /*
316 * We may have finished replacing a device.
317 * Let the async thread assess this and handle the detach.
318 */
319 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
320 }
321
322 scn->scn_phys.scn_end_time = gethrestime_sec();
323 }
324
325 /* ARGSUSED */
326 static int
327 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
328 {
329 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
330
331 if (scn->scn_phys.scn_state != DSS_SCANNING)
332 return (SET_ERROR(ENOENT));
333 return (0);
334 }
335
336 /* ARGSUSED */
337 static void
338 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
339 {
340 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
341
342 dsl_scan_done(scn, B_FALSE, tx);
343 dsl_scan_sync_state(scn, tx);
344 }
345
346 int
347 dsl_scan_cancel(dsl_pool_t *dp)
348 {
349 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
350 dsl_scan_cancel_sync, NULL, 3));
351 }
352
353 static void dsl_scan_visitbp(blkptr_t *bp,
354 const zbookmark_t *zb, dnode_phys_t *dnp, arc_buf_t *pbuf,
355 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
356 dmu_tx_t *tx);
357 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
358 dmu_objset_type_t ostype,
359 dnode_phys_t *dnp, arc_buf_t *buf, uint64_t object, dmu_tx_t *tx);
360
361 void
362 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
363 {
364 zio_free(dp->dp_spa, txg, bp);
365 }
366
367 void
368 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
369 {
370 ASSERT(dsl_pool_sync_context(dp));
371 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
372 }
373
374 static uint64_t
375 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
376 {
377 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
378 if (dsl_dataset_is_snapshot(ds))
379 return (MIN(smt, ds->ds_phys->ds_creation_txg));
380 return (smt);
381 }
382
383 static void
384 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
385 {
386 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
387 DMU_POOL_DIRECTORY_OBJECT,
388 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
389 &scn->scn_phys, tx));
390 }
391
392 static boolean_t
393 dsl_scan_check_pause(dsl_scan_t *scn, const zbookmark_t *zb)
394 {
395 uint64_t elapsed_nanosecs;
396 int mintime;
397
398 /* we never skip user/group accounting objects */
399 if (zb && (int64_t)zb->zb_object < 0)
400 return (B_FALSE);
401
402 if (scn->scn_pausing)
403 return (B_TRUE); /* we're already pausing */
404
405 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
406 return (B_FALSE); /* we're resuming */
407
408 /* We only know how to resume from level-0 blocks. */
409 if (zb && zb->zb_level != 0)
410 return (B_FALSE);
411
412 mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
413 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
414 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
415 if (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
416 (NSEC2MSEC(elapsed_nanosecs) > mintime &&
417 txg_sync_waiting(scn->scn_dp)) ||
418 spa_shutting_down(scn->scn_dp->dp_spa)) {
419 if (zb) {
420 dprintf("pausing at bookmark %llx/%llx/%llx/%llx\n",
421 (longlong_t)zb->zb_objset,
422 (longlong_t)zb->zb_object,
423 (longlong_t)zb->zb_level,
424 (longlong_t)zb->zb_blkid);
425 scn->scn_phys.scn_bookmark = *zb;
426 }
427 dprintf("pausing at DDT bookmark %llx/%llx/%llx/%llx\n",
428 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
429 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
430 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
431 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
432 scn->scn_pausing = B_TRUE;
433 return (B_TRUE);
434 }
435 return (B_FALSE);
436 }
437
438 typedef struct zil_scan_arg {
439 dsl_pool_t *zsa_dp;
440 zil_header_t *zsa_zh;
441 } zil_scan_arg_t;
442
443 /* ARGSUSED */
444 static int
445 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
446 {
447 zil_scan_arg_t *zsa = arg;
448 dsl_pool_t *dp = zsa->zsa_dp;
449 dsl_scan_t *scn = dp->dp_scan;
450 zil_header_t *zh = zsa->zsa_zh;
451 zbookmark_t zb;
452
453 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
454 return (0);
455
456 /*
457 * One block ("stubby") can be allocated a long time ago; we
458 * want to visit that one because it has been allocated
459 * (on-disk) even if it hasn't been claimed (even though for
460 * scrub there's nothing to do to it).
461 */
462 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(dp->dp_spa))
463 return (0);
464
465 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
466 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
467
468 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
469 return (0);
470 }
471
472 /* ARGSUSED */
473 static int
474 dsl_scan_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
475 {
476 if (lrc->lrc_txtype == TX_WRITE) {
477 zil_scan_arg_t *zsa = arg;
478 dsl_pool_t *dp = zsa->zsa_dp;
479 dsl_scan_t *scn = dp->dp_scan;
480 zil_header_t *zh = zsa->zsa_zh;
481 lr_write_t *lr = (lr_write_t *)lrc;
482 blkptr_t *bp = &lr->lr_blkptr;
483 zbookmark_t zb;
484
485 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
486 return (0);
487
488 /*
489 * birth can be < claim_txg if this record's txg is
490 * already txg sync'ed (but this log block contains
491 * other records that are not synced)
492 */
493 if (claim_txg == 0 || bp->blk_birth < claim_txg)
494 return (0);
495
496 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
497 lr->lr_foid, ZB_ZIL_LEVEL,
498 lr->lr_offset / BP_GET_LSIZE(bp));
499
500 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
501 }
502 return (0);
503 }
504
505 static void
506 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
507 {
508 uint64_t claim_txg = zh->zh_claim_txg;
509 zil_scan_arg_t zsa = { dp, zh };
510 zilog_t *zilog;
511
512 /*
513 * We only want to visit blocks that have been claimed but not yet
514 * replayed (or, in read-only mode, blocks that *would* be claimed).
515 */
516 if (claim_txg == 0 && spa_writeable(dp->dp_spa))
517 return;
518
519 zilog = zil_alloc(dp->dp_meta_objset, zh);
520
521 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
522 claim_txg);
523
524 zil_free(zilog);
525 }
526
527 /* ARGSUSED */
528 static void
529 dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
530 uint64_t objset, uint64_t object, uint64_t blkid)
531 {
532 zbookmark_t czb;
533 uint32_t flags = ARC_NOWAIT | ARC_PREFETCH;
534
535 if (zfs_no_scrub_prefetch)
536 return;
537
538 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_min_txg ||
539 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE))
540 return;
541
542 SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
543
544 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
545 NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
546 ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
547 }
548
549 static boolean_t
550 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
551 const zbookmark_t *zb)
552 {
553 /*
554 * We never skip over user/group accounting objects (obj<0)
555 */
556 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
557 (int64_t)zb->zb_object >= 0) {
558 /*
559 * If we already visited this bp & everything below (in
560 * a prior txg sync), don't bother doing it again.
561 */
562 if (zbookmark_is_before(dnp, zb, &scn->scn_phys.scn_bookmark))
563 return (B_TRUE);
564
565 /*
566 * If we found the block we're trying to resume from, or
567 * we went past it to a different object, zero it out to
568 * indicate that it's OK to start checking for pausing
569 * again.
570 */
571 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
572 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
573 dprintf("resuming at %llx/%llx/%llx/%llx\n",
574 (longlong_t)zb->zb_objset,
575 (longlong_t)zb->zb_object,
576 (longlong_t)zb->zb_level,
577 (longlong_t)zb->zb_blkid);
578 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
579 }
580 }
581 return (B_FALSE);
582 }
583
584 /*
585 * Return nonzero on i/o error.
586 * Return new buf to write out in *bufp.
587 */
588 static int
589 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
590 dnode_phys_t *dnp, const blkptr_t *bp,
591 const zbookmark_t *zb, dmu_tx_t *tx, arc_buf_t **bufp)
592 {
593 dsl_pool_t *dp = scn->scn_dp;
594 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
595 int err;
596
597 if (BP_GET_LEVEL(bp) > 0) {
598 uint32_t flags = ARC_WAIT;
599 int i;
600 blkptr_t *cbp;
601 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
602
603 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
604 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
605 if (err) {
606 scn->scn_phys.scn_errors++;
607 return (err);
608 }
609 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
610 dsl_scan_prefetch(scn, *bufp, cbp, zb->zb_objset,
611 zb->zb_object, zb->zb_blkid * epb + i);
612 }
613 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
614 zbookmark_t czb;
615
616 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
617 zb->zb_level - 1,
618 zb->zb_blkid * epb + i);
619 dsl_scan_visitbp(cbp, &czb, dnp,
620 *bufp, ds, scn, ostype, tx);
621 }
622 } else if (BP_GET_TYPE(bp) == DMU_OT_USERGROUP_USED) {
623 uint32_t flags = ARC_WAIT;
624
625 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
626 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
627 if (err) {
628 scn->scn_phys.scn_errors++;
629 return (err);
630 }
631 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
632 uint32_t flags = ARC_WAIT;
633 dnode_phys_t *cdnp;
634 int i, j;
635 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
636
637 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
638 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
639 if (err) {
640 scn->scn_phys.scn_errors++;
641 return (err);
642 }
643 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
644 for (j = 0; j < cdnp->dn_nblkptr; j++) {
645 blkptr_t *cbp = &cdnp->dn_blkptr[j];
646 dsl_scan_prefetch(scn, *bufp, cbp,
647 zb->zb_objset, zb->zb_blkid * epb + i, j);
648 }
649 }
650 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
651 dsl_scan_visitdnode(scn, ds, ostype,
652 cdnp, *bufp, zb->zb_blkid * epb + i, tx);
653 }
654
655 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
656 uint32_t flags = ARC_WAIT;
657 objset_phys_t *osp;
658
659 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
660 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
661 if (err) {
662 scn->scn_phys.scn_errors++;
663 return (err);
664 }
665
666 osp = (*bufp)->b_data;
667
668 dsl_scan_visitdnode(scn, ds, osp->os_type,
669 &osp->os_meta_dnode, *bufp, DMU_META_DNODE_OBJECT, tx);
670
671 if (OBJSET_BUF_HAS_USERUSED(*bufp)) {
672 /*
673 * We also always visit user/group accounting
674 * objects, and never skip them, even if we are
675 * pausing. This is necessary so that the space
676 * deltas from this txg get integrated.
677 */
678 dsl_scan_visitdnode(scn, ds, osp->os_type,
679 &osp->os_groupused_dnode, *bufp,
680 DMU_GROUPUSED_OBJECT, tx);
681 dsl_scan_visitdnode(scn, ds, osp->os_type,
682 &osp->os_userused_dnode, *bufp,
683 DMU_USERUSED_OBJECT, tx);
684 }
685 }
686
687 return (0);
688 }
689
690 static void
691 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
692 dmu_objset_type_t ostype, dnode_phys_t *dnp, arc_buf_t *buf,
693 uint64_t object, dmu_tx_t *tx)
694 {
695 int j;
696
697 for (j = 0; j < dnp->dn_nblkptr; j++) {
698 zbookmark_t czb;
699
700 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
701 dnp->dn_nlevels - 1, j);
702 dsl_scan_visitbp(&dnp->dn_blkptr[j],
703 &czb, dnp, buf, ds, scn, ostype, tx);
704 }
705
706 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
707 zbookmark_t czb;
708 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
709 0, DMU_SPILL_BLKID);
710 dsl_scan_visitbp(&dnp->dn_spill,
711 &czb, dnp, buf, ds, scn, ostype, tx);
712 }
713 }
714
715 /*
716 * The arguments are in this order because mdb can only print the
717 * first 5; we want them to be useful.
718 */
719 static void
720 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_t *zb,
721 dnode_phys_t *dnp, arc_buf_t *pbuf,
722 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
723 dmu_tx_t *tx)
724 {
725 dsl_pool_t *dp = scn->scn_dp;
726 arc_buf_t *buf = NULL;
727 blkptr_t bp_toread = *bp;
728
729 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
730
731 if (dsl_scan_check_pause(scn, zb))
732 return;
733
734 if (dsl_scan_check_resume(scn, dnp, zb))
735 return;
736
737 if (bp->blk_birth == 0)
738 return;
739
740 scn->scn_visited_this_txg++;
741
742 dprintf_bp(bp,
743 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx buf=%p bp=%p",
744 ds, ds ? ds->ds_object : 0,
745 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
746 pbuf, bp);
747
748 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
749 return;
750
751 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx,
752 &buf) != 0)
753 return;
754
755 /*
756 * If dsl_scan_ddt() has aready visited this block, it will have
757 * already done any translations or scrubbing, so don't call the
758 * callback again.
759 */
760 if (ddt_class_contains(dp->dp_spa,
761 scn->scn_phys.scn_ddt_class_max, bp)) {
762 ASSERT(buf == NULL);
763 return;
764 }
765
766 /*
767 * If this block is from the future (after cur_max_txg), then we
768 * are doing this on behalf of a deleted snapshot, and we will
769 * revisit the future block on the next pass of this dataset.
770 * Don't scan it now unless we need to because something
771 * under it was modified.
772 */
773 if (BP_PHYSICAL_BIRTH(bp) <= scn->scn_phys.scn_cur_max_txg) {
774 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
775 }
776 if (buf)
777 (void) arc_buf_remove_ref(buf, &buf);
778 }
779
780 static void
781 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
782 dmu_tx_t *tx)
783 {
784 zbookmark_t zb;
785
786 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
787 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
788 dsl_scan_visitbp(bp, &zb, NULL, NULL,
789 ds, scn, DMU_OST_NONE, tx);
790
791 dprintf_ds(ds, "finished scan%s", "");
792 }
793
794 void
795 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
796 {
797 dsl_pool_t *dp = ds->ds_dir->dd_pool;
798 dsl_scan_t *scn = dp->dp_scan;
799 uint64_t mintxg;
800
801 if (scn->scn_phys.scn_state != DSS_SCANNING)
802 return;
803
804 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
805 if (dsl_dataset_is_snapshot(ds)) {
806 /* Note, scn_cur_{min,max}_txg stays the same. */
807 scn->scn_phys.scn_bookmark.zb_objset =
808 ds->ds_phys->ds_next_snap_obj;
809 zfs_dbgmsg("destroying ds %llu; currently traversing; "
810 "reset zb_objset to %llu",
811 (u_longlong_t)ds->ds_object,
812 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
813 scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
814 } else {
815 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
816 ZB_DESTROYED_OBJSET, 0, 0, 0);
817 zfs_dbgmsg("destroying ds %llu; currently traversing; "
818 "reset bookmark to -1,0,0,0",
819 (u_longlong_t)ds->ds_object);
820 }
821 } else if (zap_lookup_int_key(dp->dp_meta_objset,
822 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
823 ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
824 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
825 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
826 if (dsl_dataset_is_snapshot(ds)) {
827 /*
828 * We keep the same mintxg; it could be >
829 * ds_creation_txg if the previous snapshot was
830 * deleted too.
831 */
832 VERIFY(zap_add_int_key(dp->dp_meta_objset,
833 scn->scn_phys.scn_queue_obj,
834 ds->ds_phys->ds_next_snap_obj, mintxg, tx) == 0);
835 zfs_dbgmsg("destroying ds %llu; in queue; "
836 "replacing with %llu",
837 (u_longlong_t)ds->ds_object,
838 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
839 } else {
840 zfs_dbgmsg("destroying ds %llu; in queue; removing",
841 (u_longlong_t)ds->ds_object);
842 }
843 } else {
844 zfs_dbgmsg("destroying ds %llu; ignoring",
845 (u_longlong_t)ds->ds_object);
846 }
847
848 /*
849 * dsl_scan_sync() should be called after this, and should sync
850 * out our changed state, but just to be safe, do it here.
851 */
852 dsl_scan_sync_state(scn, tx);
853 }
854
855 void
856 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
857 {
858 dsl_pool_t *dp = ds->ds_dir->dd_pool;
859 dsl_scan_t *scn = dp->dp_scan;
860 uint64_t mintxg;
861
862 if (scn->scn_phys.scn_state != DSS_SCANNING)
863 return;
864
865 ASSERT(ds->ds_phys->ds_prev_snap_obj != 0);
866
867 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
868 scn->scn_phys.scn_bookmark.zb_objset =
869 ds->ds_phys->ds_prev_snap_obj;
870 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
871 "reset zb_objset to %llu",
872 (u_longlong_t)ds->ds_object,
873 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
874 } else if (zap_lookup_int_key(dp->dp_meta_objset,
875 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
876 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
877 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
878 VERIFY(zap_add_int_key(dp->dp_meta_objset,
879 scn->scn_phys.scn_queue_obj,
880 ds->ds_phys->ds_prev_snap_obj, mintxg, tx) == 0);
881 zfs_dbgmsg("snapshotting ds %llu; in queue; "
882 "replacing with %llu",
883 (u_longlong_t)ds->ds_object,
884 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
885 }
886 dsl_scan_sync_state(scn, tx);
887 }
888
889 void
890 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
891 {
892 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
893 dsl_scan_t *scn = dp->dp_scan;
894 uint64_t mintxg;
895
896 if (scn->scn_phys.scn_state != DSS_SCANNING)
897 return;
898
899 if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
900 scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
901 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
902 "reset zb_objset to %llu",
903 (u_longlong_t)ds1->ds_object,
904 (u_longlong_t)ds2->ds_object);
905 } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
906 scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
907 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
908 "reset zb_objset to %llu",
909 (u_longlong_t)ds2->ds_object,
910 (u_longlong_t)ds1->ds_object);
911 }
912
913 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
914 ds1->ds_object, &mintxg) == 0) {
915 int err;
916
917 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
918 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
919 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
920 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
921 err = zap_add_int_key(dp->dp_meta_objset,
922 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
923 VERIFY(err == 0 || err == EEXIST);
924 if (err == EEXIST) {
925 /* Both were there to begin with */
926 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
927 scn->scn_phys.scn_queue_obj,
928 ds1->ds_object, mintxg, tx));
929 }
930 zfs_dbgmsg("clone_swap ds %llu; in queue; "
931 "replacing with %llu",
932 (u_longlong_t)ds1->ds_object,
933 (u_longlong_t)ds2->ds_object);
934 } else if (zap_lookup_int_key(dp->dp_meta_objset,
935 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
936 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
937 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
938 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
939 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
940 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
941 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
942 zfs_dbgmsg("clone_swap ds %llu; in queue; "
943 "replacing with %llu",
944 (u_longlong_t)ds2->ds_object,
945 (u_longlong_t)ds1->ds_object);
946 }
947
948 dsl_scan_sync_state(scn, tx);
949 }
950
951 struct enqueue_clones_arg {
952 dmu_tx_t *tx;
953 uint64_t originobj;
954 };
955
956 /* ARGSUSED */
957 static int
958 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
959 {
960 struct enqueue_clones_arg *eca = arg;
961 dsl_dataset_t *ds;
962 int err;
963 dsl_scan_t *scn = dp->dp_scan;
964
965 if (hds->ds_dir->dd_phys->dd_origin_obj != eca->originobj)
966 return (0);
967
968 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
969 if (err)
970 return (err);
971
972 while (ds->ds_phys->ds_prev_snap_obj != eca->originobj) {
973 dsl_dataset_t *prev;
974 err = dsl_dataset_hold_obj(dp,
975 ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
976
977 dsl_dataset_rele(ds, FTAG);
978 if (err)
979 return (err);
980 ds = prev;
981 }
982 VERIFY(zap_add_int_key(dp->dp_meta_objset,
983 scn->scn_phys.scn_queue_obj, ds->ds_object,
984 ds->ds_phys->ds_prev_snap_txg, eca->tx) == 0);
985 dsl_dataset_rele(ds, FTAG);
986 return (0);
987 }
988
989 static void
990 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
991 {
992 dsl_pool_t *dp = scn->scn_dp;
993 dsl_dataset_t *ds;
994 objset_t *os;
995
996 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
997
998 if (dmu_objset_from_ds(ds, &os))
999 goto out;
1000
1001 /*
1002 * Only the ZIL in the head (non-snapshot) is valid. Even though
1003 * snapshots can have ZIL block pointers (which may be the same
1004 * BP as in the head), they must be ignored. So we traverse the
1005 * ZIL here, rather than in scan_recurse(), because the regular
1006 * snapshot block-sharing rules don't apply to it.
1007 */
1008 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !dsl_dataset_is_snapshot(ds))
1009 dsl_scan_zil(dp, &os->os_zil_header);
1010
1011 /*
1012 * Iterate over the bps in this ds.
1013 */
1014 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1015 dsl_scan_visit_rootbp(scn, ds, &ds->ds_phys->ds_bp, tx);
1016
1017 char *dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
1018 dsl_dataset_name(ds, dsname);
1019 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1020 "pausing=%u",
1021 (longlong_t)dsobj, dsname,
1022 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1023 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1024 (int)scn->scn_pausing);
1025 kmem_free(dsname, ZFS_MAXNAMELEN);
1026
1027 if (scn->scn_pausing)
1028 goto out;
1029
1030 /*
1031 * We've finished this pass over this dataset.
1032 */
1033
1034 /*
1035 * If we did not completely visit this dataset, do another pass.
1036 */
1037 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1038 zfs_dbgmsg("incomplete pass; visiting again");
1039 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1040 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1041 scn->scn_phys.scn_queue_obj, ds->ds_object,
1042 scn->scn_phys.scn_cur_max_txg, tx) == 0);
1043 goto out;
1044 }
1045
1046 /*
1047 * Add descendent datasets to work queue.
1048 */
1049 if (ds->ds_phys->ds_next_snap_obj != 0) {
1050 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1051 scn->scn_phys.scn_queue_obj, ds->ds_phys->ds_next_snap_obj,
1052 ds->ds_phys->ds_creation_txg, tx) == 0);
1053 }
1054 if (ds->ds_phys->ds_num_children > 1) {
1055 boolean_t usenext = B_FALSE;
1056 if (ds->ds_phys->ds_next_clones_obj != 0) {
1057 uint64_t count;
1058 /*
1059 * A bug in a previous version of the code could
1060 * cause upgrade_clones_cb() to not set
1061 * ds_next_snap_obj when it should, leading to a
1062 * missing entry. Therefore we can only use the
1063 * next_clones_obj when its count is correct.
1064 */
1065 int err = zap_count(dp->dp_meta_objset,
1066 ds->ds_phys->ds_next_clones_obj, &count);
1067 if (err == 0 &&
1068 count == ds->ds_phys->ds_num_children - 1)
1069 usenext = B_TRUE;
1070 }
1071
1072 if (usenext) {
1073 VERIFY0(zap_join_key(dp->dp_meta_objset,
1074 ds->ds_phys->ds_next_clones_obj,
1075 scn->scn_phys.scn_queue_obj,
1076 ds->ds_phys->ds_creation_txg, tx));
1077 } else {
1078 struct enqueue_clones_arg eca;
1079 eca.tx = tx;
1080 eca.originobj = ds->ds_object;
1081
1082 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1083 enqueue_clones_cb, &eca, DS_FIND_CHILDREN));
1084 }
1085 }
1086
1087 out:
1088 dsl_dataset_rele(ds, FTAG);
1089 }
1090
1091 /* ARGSUSED */
1092 static int
1093 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1094 {
1095 dmu_tx_t *tx = arg;
1096 dsl_dataset_t *ds;
1097 int err;
1098 dsl_scan_t *scn = dp->dp_scan;
1099
1100 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1101 if (err)
1102 return (err);
1103
1104 while (ds->ds_phys->ds_prev_snap_obj != 0) {
1105 dsl_dataset_t *prev;
1106 err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
1107 FTAG, &prev);
1108 if (err) {
1109 dsl_dataset_rele(ds, FTAG);
1110 return (err);
1111 }
1112
1113 /*
1114 * If this is a clone, we don't need to worry about it for now.
1115 */
1116 if (prev->ds_phys->ds_next_snap_obj != ds->ds_object) {
1117 dsl_dataset_rele(ds, FTAG);
1118 dsl_dataset_rele(prev, FTAG);
1119 return (0);
1120 }
1121 dsl_dataset_rele(ds, FTAG);
1122 ds = prev;
1123 }
1124
1125 VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1126 ds->ds_object, ds->ds_phys->ds_prev_snap_txg, tx) == 0);
1127 dsl_dataset_rele(ds, FTAG);
1128 return (0);
1129 }
1130
1131 /*
1132 * Scrub/dedup interaction.
1133 *
1134 * If there are N references to a deduped block, we don't want to scrub it
1135 * N times -- ideally, we should scrub it exactly once.
1136 *
1137 * We leverage the fact that the dde's replication class (enum ddt_class)
1138 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1139 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1140 *
1141 * To prevent excess scrubbing, the scrub begins by walking the DDT
1142 * to find all blocks with refcnt > 1, and scrubs each of these once.
1143 * Since there are two replication classes which contain blocks with
1144 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1145 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1146 *
1147 * There would be nothing more to say if a block's refcnt couldn't change
1148 * during a scrub, but of course it can so we must account for changes
1149 * in a block's replication class.
1150 *
1151 * Here's an example of what can occur:
1152 *
1153 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
1154 * when visited during the top-down scrub phase, it will be scrubbed twice.
1155 * This negates our scrub optimization, but is otherwise harmless.
1156 *
1157 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1158 * on each visit during the top-down scrub phase, it will never be scrubbed.
1159 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1160 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1161 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1162 * while a scrub is in progress, it scrubs the block right then.
1163 */
1164 static void
1165 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1166 {
1167 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1168 ddt_entry_t dde = { 0 };
1169 int error;
1170 uint64_t n = 0;
1171
1172 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1173 ddt_t *ddt;
1174
1175 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1176 break;
1177 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1178 (longlong_t)ddb->ddb_class,
1179 (longlong_t)ddb->ddb_type,
1180 (longlong_t)ddb->ddb_checksum,
1181 (longlong_t)ddb->ddb_cursor);
1182
1183 /* There should be no pending changes to the dedup table */
1184 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1185 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
1186
1187 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1188 n++;
1189
1190 if (dsl_scan_check_pause(scn, NULL))
1191 break;
1192 }
1193
1194 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; pausing=%u",
1195 (longlong_t)n, (int)scn->scn_phys.scn_ddt_class_max,
1196 (int)scn->scn_pausing);
1197
1198 ASSERT(error == 0 || error == ENOENT);
1199 ASSERT(error != ENOENT ||
1200 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1201 }
1202
1203 /* ARGSUSED */
1204 void
1205 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1206 ddt_entry_t *dde, dmu_tx_t *tx)
1207 {
1208 const ddt_key_t *ddk = &dde->dde_key;
1209 ddt_phys_t *ddp = dde->dde_phys;
1210 blkptr_t bp;
1211 zbookmark_t zb = { 0 };
1212
1213 if (scn->scn_phys.scn_state != DSS_SCANNING)
1214 return;
1215
1216 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1217 if (ddp->ddp_phys_birth == 0 ||
1218 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
1219 continue;
1220 ddt_bp_create(checksum, ddk, ddp, &bp);
1221
1222 scn->scn_visited_this_txg++;
1223 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1224 }
1225 }
1226
1227 static void
1228 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1229 {
1230 dsl_pool_t *dp = scn->scn_dp;
1231 zap_cursor_t zc;
1232 zap_attribute_t za;
1233
1234 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1235 scn->scn_phys.scn_ddt_class_max) {
1236 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1237 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1238 dsl_scan_ddt(scn, tx);
1239 if (scn->scn_pausing)
1240 return;
1241 }
1242
1243 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1244 /* First do the MOS & ORIGIN */
1245
1246 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1247 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1248 dsl_scan_visit_rootbp(scn, NULL,
1249 &dp->dp_meta_rootbp, tx);
1250 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1251 if (scn->scn_pausing)
1252 return;
1253
1254 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1255 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1256 enqueue_cb, tx, DS_FIND_CHILDREN));
1257 } else {
1258 dsl_scan_visitds(scn,
1259 dp->dp_origin_snap->ds_object, tx);
1260 }
1261 ASSERT(!scn->scn_pausing);
1262 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
1263 ZB_DESTROYED_OBJSET) {
1264 /*
1265 * If we were paused, continue from here. Note if the
1266 * ds we were paused on was deleted, the zb_objset may
1267 * be -1, so we will skip this and find a new objset
1268 * below.
1269 */
1270 dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
1271 if (scn->scn_pausing)
1272 return;
1273 }
1274
1275 /*
1276 * In case we were paused right at the end of the ds, zero the
1277 * bookmark so we don't think that we're still trying to resume.
1278 */
1279 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_t));
1280
1281 /* keep pulling things out of the zap-object-as-queue */
1282 while (zap_cursor_init(&zc, dp->dp_meta_objset,
1283 scn->scn_phys.scn_queue_obj),
1284 zap_cursor_retrieve(&zc, &za) == 0) {
1285 dsl_dataset_t *ds;
1286 uint64_t dsobj;
1287
1288 dsobj = strtonum(za.za_name, NULL);
1289 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1290 scn->scn_phys.scn_queue_obj, dsobj, tx));
1291
1292 /* Set up min/max txg */
1293 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1294 if (za.za_first_integer != 0) {
1295 scn->scn_phys.scn_cur_min_txg =
1296 MAX(scn->scn_phys.scn_min_txg,
1297 za.za_first_integer);
1298 } else {
1299 scn->scn_phys.scn_cur_min_txg =
1300 MAX(scn->scn_phys.scn_min_txg,
1301 ds->ds_phys->ds_prev_snap_txg);
1302 }
1303 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
1304 dsl_dataset_rele(ds, FTAG);
1305
1306 dsl_scan_visitds(scn, dsobj, tx);
1307 zap_cursor_fini(&zc);
1308 if (scn->scn_pausing)
1309 return;
1310 }
1311 zap_cursor_fini(&zc);
1312 }
1313
1314 static boolean_t
1315 dsl_scan_free_should_pause(dsl_scan_t *scn)
1316 {
1317 uint64_t elapsed_nanosecs;
1318
1319 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
1320 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
1321 (NSEC2MSEC(elapsed_nanosecs) > zfs_free_min_time_ms &&
1322 txg_sync_waiting(scn->scn_dp)) ||
1323 spa_shutting_down(scn->scn_dp->dp_spa));
1324 }
1325
1326 static int
1327 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1328 {
1329 dsl_scan_t *scn = arg;
1330
1331 if (!scn->scn_is_bptree ||
1332 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
1333 if (dsl_scan_free_should_pause(scn))
1334 return (SET_ERROR(ERESTART));
1335 }
1336
1337 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
1338 dmu_tx_get_txg(tx), bp, 0));
1339 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
1340 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
1341 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
1342 scn->scn_visited_this_txg++;
1343 return (0);
1344 }
1345
1346 boolean_t
1347 dsl_scan_active(dsl_scan_t *scn)
1348 {
1349 spa_t *spa = scn->scn_dp->dp_spa;
1350 uint64_t used = 0, comp, uncomp;
1351
1352 if (spa->spa_load_state != SPA_LOAD_NONE)
1353 return (B_FALSE);
1354 if (spa_shutting_down(spa))
1355 return (B_FALSE);
1356
1357 if (scn->scn_phys.scn_state == DSS_SCANNING ||
1358 scn->scn_async_destroying)
1359 return (B_TRUE);
1360
1361 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1362 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
1363 &used, &comp, &uncomp);
1364 }
1365 return (used != 0);
1366 }
1367
1368 void
1369 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
1370 {
1371 dsl_scan_t *scn = dp->dp_scan;
1372 spa_t *spa = dp->dp_spa;
1373 int err;
1374
1375 /*
1376 * Check for scn_restart_txg before checking spa_load_state, so
1377 * that we can restart an old-style scan while the pool is being
1378 * imported (see dsl_scan_init).
1379 */
1380 if (scn->scn_restart_txg != 0 &&
1381 scn->scn_restart_txg <= tx->tx_txg) {
1382 pool_scan_func_t func = POOL_SCAN_SCRUB;
1383 dsl_scan_done(scn, B_FALSE, tx);
1384 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
1385 func = POOL_SCAN_RESILVER;
1386 zfs_dbgmsg("restarting scan func=%u txg=%llu",
1387 func, tx->tx_txg);
1388 dsl_scan_setup_sync(&func, tx);
1389 }
1390
1391 if (!dsl_scan_active(scn) ||
1392 spa_sync_pass(dp->dp_spa) > 1)
1393 return;
1394
1395 scn->scn_visited_this_txg = 0;
1396 scn->scn_pausing = B_FALSE;
1397 scn->scn_sync_start_time = gethrtime();
1398 spa->spa_scrub_active = B_TRUE;
1399
1400 /*
1401 * First process the free list. If we pause the free, don't do
1402 * any scanning. This ensures that there is no free list when
1403 * we are scanning, so the scan code doesn't have to worry about
1404 * traversing it.
1405 */
1406 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1407 scn->scn_is_bptree = B_FALSE;
1408 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1409 NULL, ZIO_FLAG_MUSTSUCCEED);
1410 err = bpobj_iterate(&dp->dp_free_bpobj,
1411 dsl_scan_free_block_cb, scn, tx);
1412 VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
1413
1414 if (err == 0 && spa_feature_is_active(spa,
1415 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
1416 ASSERT(scn->scn_async_destroying);
1417 scn->scn_is_bptree = B_TRUE;
1418 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1419 NULL, ZIO_FLAG_MUSTSUCCEED);
1420 err = bptree_iterate(dp->dp_meta_objset,
1421 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb,
1422 scn, tx);
1423 VERIFY0(zio_wait(scn->scn_zio_root));
1424
1425 if (err == 0) {
1426 zfeature_info_t *feat = &spa_feature_table
1427 [SPA_FEATURE_ASYNC_DESTROY];
1428 /* finished; deactivate async destroy feature */
1429 spa_feature_decr(spa, feat, tx);
1430 ASSERT(!spa_feature_is_active(spa, feat));
1431 VERIFY0(zap_remove(dp->dp_meta_objset,
1432 DMU_POOL_DIRECTORY_OBJECT,
1433 DMU_POOL_BPTREE_OBJ, tx));
1434 VERIFY0(bptree_free(dp->dp_meta_objset,
1435 dp->dp_bptree_obj, tx));
1436 dp->dp_bptree_obj = 0;
1437 scn->scn_async_destroying = B_FALSE;
1438 }
1439 }
1440 if (scn->scn_visited_this_txg) {
1441 zfs_dbgmsg("freed %llu blocks in %llums from "
1442 "free_bpobj/bptree txg %llu",
1443 (longlong_t)scn->scn_visited_this_txg,
1444 (longlong_t)
1445 NSEC2MSEC(gethrtime() - scn->scn_sync_start_time),
1446 (longlong_t)tx->tx_txg);
1447 scn->scn_visited_this_txg = 0;
1448 /*
1449 * Re-sync the ddt so that we can further modify
1450 * it when doing bprewrite.
1451 */
1452 ddt_sync(spa, tx->tx_txg);
1453 }
1454 if (err == ERESTART)
1455 return;
1456 }
1457
1458 if (scn->scn_phys.scn_state != DSS_SCANNING)
1459 return;
1460
1461 if (scn->scn_done_txg == tx->tx_txg) {
1462 ASSERT(!scn->scn_pausing);
1463 /* finished with scan. */
1464 zfs_dbgmsg("txg %llu scan complete", tx->tx_txg);
1465 dsl_scan_done(scn, B_TRUE, tx);
1466 ASSERT3U(spa->spa_scrub_inflight, ==, 0);
1467 dsl_scan_sync_state(scn, tx);
1468 return;
1469 }
1470
1471 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1472 scn->scn_phys.scn_ddt_class_max) {
1473 zfs_dbgmsg("doing scan sync txg %llu; "
1474 "ddt bm=%llu/%llu/%llu/%llx",
1475 (longlong_t)tx->tx_txg,
1476 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1477 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1478 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1479 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1480 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
1481 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
1482 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
1483 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
1484 } else {
1485 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
1486 (longlong_t)tx->tx_txg,
1487 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
1488 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
1489 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
1490 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
1491 }
1492
1493 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1494 NULL, ZIO_FLAG_CANFAIL);
1495 dsl_pool_config_enter(dp, FTAG);
1496 dsl_scan_visit(scn, tx);
1497 dsl_pool_config_exit(dp, FTAG);
1498 (void) zio_wait(scn->scn_zio_root);
1499 scn->scn_zio_root = NULL;
1500
1501 zfs_dbgmsg("visited %llu blocks in %llums",
1502 (longlong_t)scn->scn_visited_this_txg,
1503 (longlong_t)NSEC2MSEC(gethrtime() - scn->scn_sync_start_time));
1504
1505 if (!scn->scn_pausing) {
1506 scn->scn_done_txg = tx->tx_txg + 1;
1507 zfs_dbgmsg("txg %llu traversal complete, waiting till txg %llu",
1508 tx->tx_txg, scn->scn_done_txg);
1509 }
1510
1511 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
1512 mutex_enter(&spa->spa_scrub_lock);
1513 while (spa->spa_scrub_inflight > 0) {
1514 cv_wait(&spa->spa_scrub_io_cv,
1515 &spa->spa_scrub_lock);
1516 }
1517 mutex_exit(&spa->spa_scrub_lock);
1518 }
1519
1520 dsl_scan_sync_state(scn, tx);
1521 }
1522
1523 /*
1524 * This will start a new scan, or restart an existing one.
1525 */
1526 void
1527 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
1528 {
1529 if (txg == 0) {
1530 dmu_tx_t *tx;
1531 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1532 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1533
1534 txg = dmu_tx_get_txg(tx);
1535 dp->dp_scan->scn_restart_txg = txg;
1536 dmu_tx_commit(tx);
1537 } else {
1538 dp->dp_scan->scn_restart_txg = txg;
1539 }
1540 zfs_dbgmsg("restarting resilver txg=%llu", txg);
1541 }
1542
1543 boolean_t
1544 dsl_scan_resilvering(dsl_pool_t *dp)
1545 {
1546 return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
1547 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
1548 }
1549
1550 /*
1551 * scrub consumers
1552 */
1553
1554 static void
1555 count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
1556 {
1557 int i;
1558
1559 /*
1560 * If we resume after a reboot, zab will be NULL; don't record
1561 * incomplete stats in that case.
1562 */
1563 if (zab == NULL)
1564 return;
1565
1566 for (i = 0; i < 4; i++) {
1567 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
1568 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
1569 if (t & DMU_OT_NEWTYPE)
1570 t = DMU_OT_OTHER;
1571 zfs_blkstat_t *zb = &zab->zab_type[l][t];
1572 int equal;
1573
1574 zb->zb_count++;
1575 zb->zb_asize += BP_GET_ASIZE(bp);
1576 zb->zb_lsize += BP_GET_LSIZE(bp);
1577 zb->zb_psize += BP_GET_PSIZE(bp);
1578 zb->zb_gangs += BP_COUNT_GANG(bp);
1579
1580 switch (BP_GET_NDVAS(bp)) {
1581 case 2:
1582 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1583 DVA_GET_VDEV(&bp->blk_dva[1]))
1584 zb->zb_ditto_2_of_2_samevdev++;
1585 break;
1586 case 3:
1587 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1588 DVA_GET_VDEV(&bp->blk_dva[1])) +
1589 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1590 DVA_GET_VDEV(&bp->blk_dva[2])) +
1591 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
1592 DVA_GET_VDEV(&bp->blk_dva[2]));
1593 if (equal == 1)
1594 zb->zb_ditto_2_of_3_samevdev++;
1595 else if (equal == 3)
1596 zb->zb_ditto_3_of_3_samevdev++;
1597 break;
1598 }
1599 }
1600 }
1601
1602 static void
1603 dsl_scan_scrub_done(zio_t *zio)
1604 {
1605 spa_t *spa = zio->io_spa;
1606
1607 zio_data_buf_free(zio->io_data, zio->io_size);
1608
1609 mutex_enter(&spa->spa_scrub_lock);
1610 spa->spa_scrub_inflight--;
1611 cv_broadcast(&spa->spa_scrub_io_cv);
1612
1613 if (zio->io_error && (zio->io_error != ECKSUM ||
1614 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
1615 spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
1616 }
1617 mutex_exit(&spa->spa_scrub_lock);
1618 }
1619
1620 static int
1621 dsl_scan_scrub_cb(dsl_pool_t *dp,
1622 const blkptr_t *bp, const zbookmark_t *zb)
1623 {
1624 dsl_scan_t *scn = dp->dp_scan;
1625 size_t size = BP_GET_PSIZE(bp);
1626 spa_t *spa = dp->dp_spa;
1627 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
1628 boolean_t needs_io;
1629 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
1630 int zio_priority;
1631 int scan_delay = 0;
1632
1633 if (phys_birth <= scn->scn_phys.scn_min_txg ||
1634 phys_birth >= scn->scn_phys.scn_max_txg)
1635 return (0);
1636
1637 count_block(dp->dp_blkstats, bp);
1638
1639 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
1640 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
1641 zio_flags |= ZIO_FLAG_SCRUB;
1642 zio_priority = ZIO_PRIORITY_SCRUB;
1643 needs_io = B_TRUE;
1644 scan_delay = zfs_scrub_delay;
1645 } else {
1646 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
1647 zio_flags |= ZIO_FLAG_RESILVER;
1648 zio_priority = ZIO_PRIORITY_RESILVER;
1649 needs_io = B_FALSE;
1650 scan_delay = zfs_resilver_delay;
1651 }
1652
1653 /* If it's an intent log block, failure is expected. */
1654 if (zb->zb_level == ZB_ZIL_LEVEL)
1655 zio_flags |= ZIO_FLAG_SPECULATIVE;
1656
1657 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
1658 vdev_t *vd = vdev_lookup_top(spa,
1659 DVA_GET_VDEV(&bp->blk_dva[d]));
1660
1661 /*
1662 * Keep track of how much data we've examined so that
1663 * zpool(1M) status can make useful progress reports.
1664 */
1665 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
1666 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
1667
1668 /* if it's a resilver, this may not be in the target range */
1669 if (!needs_io) {
1670 if (DVA_GET_GANG(&bp->blk_dva[d])) {
1671 /*
1672 * Gang members may be spread across multiple
1673 * vdevs, so the best estimate we have is the
1674 * scrub range, which has already been checked.
1675 * XXX -- it would be better to change our
1676 * allocation policy to ensure that all
1677 * gang members reside on the same vdev.
1678 */
1679 needs_io = B_TRUE;
1680 } else {
1681 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
1682 phys_birth, 1);
1683 }
1684 }
1685 }
1686
1687 if (needs_io && !zfs_no_scrub_io) {
1688 vdev_t *rvd = spa->spa_root_vdev;
1689 uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
1690 void *data = zio_data_buf_alloc(size);
1691
1692 mutex_enter(&spa->spa_scrub_lock);
1693 while (spa->spa_scrub_inflight >= maxinflight)
1694 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1695 spa->spa_scrub_inflight++;
1696 mutex_exit(&spa->spa_scrub_lock);
1697
1698 /*
1699 * If we're seeing recent (zfs_scan_idle) "important" I/Os
1700 * then throttle our workload to limit the impact of a scan.
1701 */
1702 if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
1703 delay(scan_delay);
1704
1705 zio_nowait(zio_read(NULL, spa, bp, data, size,
1706 dsl_scan_scrub_done, NULL, zio_priority,
1707 zio_flags, zb));
1708 }
1709
1710 /* do not relocate this block */
1711 return (0);
1712 }
1713
1714 int
1715 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
1716 {
1717 spa_t *spa = dp->dp_spa;
1718
1719 /*
1720 * Purge all vdev caches and probe all devices. We do this here
1721 * rather than in sync context because this requires a writer lock
1722 * on the spa_config lock, which we can't do from sync context. The
1723 * spa_scrub_reopen flag indicates that vdev_open() should not
1724 * attempt to start another scrub.
1725 */
1726 spa_vdev_state_enter(spa, SCL_NONE);
1727 spa->spa_scrub_reopen = B_TRUE;
1728 vdev_reopen(spa->spa_root_vdev);
1729 spa->spa_scrub_reopen = B_FALSE;
1730 (void) spa_vdev_state_exit(spa, NULL, 0);
1731
1732 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
1733 dsl_scan_setup_sync, &func, 0));
1734 }