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 */
24
25 #include <sys/dsl_scan.h>
26 #include <sys/dsl_pool.h>
27 #include <sys/dsl_dataset.h>
28 #include <sys/dsl_prop.h>
29 #include <sys/dsl_dir.h>
30 #include <sys/dsl_synctask.h>
31 #include <sys/dnode.h>
32 #include <sys/dmu_tx.h>
33 #include <sys/dmu_objset.h>
34 #include <sys/arc.h>
35 #include <sys/zap.h>
36 #include <sys/zio.h>
37 #include <sys/zfs_context.h>
38 #include <sys/fs/zfs.h>
39 #include <sys/zfs_znode.h>
40 #include <sys/spa_impl.h>
41 #include <sys/vdev_impl.h>
42 #include <sys/zil_impl.h>
43 #include <sys/zio_checksum.h>
44 #include <sys/ddt.h>
45 #include <sys/sa.h>
46 #include <sys/sa_impl.h>
47 #ifdef _KERNEL
48 #include <sys/zfs_vfsops.h>
49 #endif
50
51 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *, const zbookmark_t *);
52
53 static scan_cb_t dsl_scan_defrag_cb;
54 static scan_cb_t dsl_scan_scrub_cb;
55 static scan_cb_t dsl_scan_remove_cb;
56 static dsl_syncfunc_t dsl_scan_cancel_sync;
57 static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *tx);
58
59 int zfs_top_maxinflight = 32; /* maximum I/Os per top-level */
60 int zfs_resilver_delay = 2; /* number of ticks to delay resilver */
61 int zfs_scrub_delay = 4; /* number of ticks to delay scrub */
62 int zfs_scan_idle = 50; /* idle window in clock ticks */
63
64 int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
65 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
66 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
67 boolean_t zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
68 boolean_t zfs_no_scrub_prefetch = B_FALSE; /* set to disable srub prefetching */
69 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
70 int dsl_scan_delay_completion = B_FALSE; /* set to delay scan completion */
71
72 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
73 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
74 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
75
76 extern int zfs_txg_timeout;
77
78 /* the order has to match pool_scan_type */
79 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
80 NULL,
81 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
82 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
83 };
84
85 int
86 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
87 {
88 int err;
89 dsl_scan_t *scn;
90 spa_t *spa = dp->dp_spa;
91 uint64_t f;
92
93 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
94 scn->scn_dp = dp;
95
96 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
97 "scrub_func", sizeof (uint64_t), 1, &f);
98 if (err == 0) {
99 /*
100 * There was an old-style scrub in progress. Restart a
101 * new-style scrub from the beginning.
102 */
103 scn->scn_restart_txg = txg;
104 zfs_dbgmsg("old-style scrub was in progress; "
105 "restarting new-style scrub in txg %llu",
106 scn->scn_restart_txg);
107
108 /*
109 * Load the queue obj from the old location so that it
110 * can be freed by dsl_scan_done().
111 */
112 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
113 "scrub_queue", sizeof (uint64_t), 1,
114 &scn->scn_phys.scn_queue_obj);
115 } else {
116 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
117 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
118 &scn->scn_phys);
119 if (err == ENOENT)
120 return (0);
121 else if (err)
122 return (err);
123
124 if (scn->scn_phys.scn_state == DSS_SCANNING &&
125 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
126 /*
127 * A new-type scrub was in progress on an old
128 * pool, and the pool was accessed by old
129 * software. Restart from the beginning, since
130 * the old software may have changed the pool in
131 * the meantime.
132 */
133 scn->scn_restart_txg = txg;
134 zfs_dbgmsg("new-style scrub was modified "
135 "by old software; restarting in txg %llu",
136 scn->scn_restart_txg);
137 }
138 }
139
140 spa_scan_stat_init(spa);
141 return (0);
142 }
143
144 void
145 dsl_scan_fini(dsl_pool_t *dp)
146 {
147 if (dp->dp_scan) {
148 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
149 dp->dp_scan = NULL;
150 }
151 }
152
153 /* ARGSUSED */
154 static int
155 dsl_scan_setup_check(void *arg1, void *arg2, dmu_tx_t *tx)
156 {
157 dsl_scan_t *scn = arg1;
158
159 if (scn->scn_phys.scn_state == DSS_SCANNING)
160 return (EBUSY);
161
162 return (0);
163 }
164
165 /* ARGSUSED */
166 static void
167 dsl_scan_setup_sync(void *arg1, void *arg2, dmu_tx_t *tx)
168 {
169 dsl_scan_t *scn = arg1;
170 pool_scan_func_t *funcp = arg2;
171 dmu_object_type_t ot = 0;
172 dsl_pool_t *dp = scn->scn_dp;
173 spa_t *spa = dp->dp_spa;
174
175 ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
176 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
177 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
178 scn->scn_phys.scn_func = *funcp;
179 scn->scn_phys.scn_state = DSS_SCANNING;
180 scn->scn_phys.scn_min_txg = 0;
181 scn->scn_phys.scn_max_txg = tx->tx_txg;
182 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
183 scn->scn_phys.scn_start_time = gethrestime_sec();
184 scn->scn_phys.scn_errors = 0;
185 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
186 scn->scn_restart_txg = 0;
187 spa_scan_stat_init(spa);
188
189 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
190 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
191
192 /* rewrite all disk labels */
193 vdev_config_dirty(spa->spa_root_vdev);
194
195 if (vdev_resilver_needed(spa->spa_root_vdev,
196 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
197 spa_event_notify(spa, NULL, ESC_ZFS_RESILVER_START);
198 } else {
199 spa_event_notify(spa, NULL, ESC_ZFS_SCRUB_START);
200 }
201
202 spa->spa_scrub_started = B_TRUE;
203 /*
204 * If this is an incremental scrub, limit the DDT scrub phase
205 * to just the auto-ditto class (for correctness); the rest
206 * of the scrub should go faster using top-down pruning.
207 */
208 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
209 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
210
211 }
212
213 /* back to the generic stuff */
214
215 if (dp->dp_blkstats == NULL) {
216 dp->dp_blkstats =
217 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
218 }
219 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
220
221 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
222 ot = DMU_OT_ZAP_OTHER;
223
224 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
225 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
226
227 dsl_scan_sync_state(scn, tx);
228
229 spa_history_log_internal(LOG_POOL_SCAN, spa, tx,
230 "func=%u mintxg=%llu maxtxg=%llu",
231 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
232 }
233
234 /* ARGSUSED */
235 static void
236 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
237 {
238 static const char *old_names[] = {
239 "scrub_bookmark",
240 "scrub_ddt_bookmark",
241 "scrub_ddt_class_max",
242 "scrub_queue",
243 "scrub_min_txg",
244 "scrub_max_txg",
245 "scrub_func",
246 "scrub_errors",
247 NULL
248 };
249
250 dsl_pool_t *dp = scn->scn_dp;
251 spa_t *spa = dp->dp_spa;
252 int i;
253
254 /* Remove any remnants of an old-style scrub. */
255 for (i = 0; old_names[i]; i++) {
256 (void) zap_remove(dp->dp_meta_objset,
257 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
258 }
259
260 if (scn->scn_phys.scn_queue_obj != 0) {
261 VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
262 scn->scn_phys.scn_queue_obj, tx));
263 scn->scn_phys.scn_queue_obj = 0;
264 }
265
266 /*
267 * If we were "restarted" from a stopped state, don't bother
268 * with anything else.
269 */
270 if (scn->scn_phys.scn_state != DSS_SCANNING)
271 return;
272
273 if (complete)
274 scn->scn_phys.scn_state = DSS_FINISHED;
275 else
276 scn->scn_phys.scn_state = DSS_CANCELED;
277
278 spa_history_log_internal(LOG_POOL_SCAN_DONE, spa, tx,
279 "complete=%u", complete);
280
281 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
282 mutex_enter(&spa->spa_scrub_lock);
283 while (spa->spa_scrub_inflight > 0) {
284 cv_wait(&spa->spa_scrub_io_cv,
285 &spa->spa_scrub_lock);
286 }
287 mutex_exit(&spa->spa_scrub_lock);
288 spa->spa_scrub_started = B_FALSE;
289 spa->spa_scrub_active = B_FALSE;
290
291 /*
292 * If the scrub/resilver completed, update all DTLs to
293 * reflect this. Whether it succeeded or not, vacate
294 * all temporary scrub DTLs.
295 */
296 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
297 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
298 if (complete) {
299 spa_event_notify(spa, NULL, scn->scn_phys.scn_min_txg ?
300 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
301 }
302 spa_errlog_rotate(spa);
303
304 /*
305 * We may have finished replacing a device.
306 * Let the async thread assess this and handle the detach.
307 */
308 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
309 }
310
311 scn->scn_phys.scn_end_time = gethrestime_sec();
312 }
313
314 /* ARGSUSED */
315 static int
316 dsl_scan_cancel_check(void *arg1, void *arg2, dmu_tx_t *tx)
317 {
318 dsl_scan_t *scn = arg1;
319
320 if (scn->scn_phys.scn_state != DSS_SCANNING)
321 return (ENOENT);
322 return (0);
323 }
324
325 /* ARGSUSED */
326 static void
327 dsl_scan_cancel_sync(void *arg1, void *arg2, dmu_tx_t *tx)
328 {
329 dsl_scan_t *scn = arg1;
330
331 dsl_scan_done(scn, B_FALSE, tx);
332 dsl_scan_sync_state(scn, tx);
333 }
334
335 int
336 dsl_scan_cancel(dsl_pool_t *dp)
337 {
338 boolean_t complete = B_FALSE;
339 int err;
340
341 err = dsl_sync_task_do(dp, dsl_scan_cancel_check,
342 dsl_scan_cancel_sync, dp->dp_scan, &complete, 3);
343 return (err);
344 }
345
346 static void dsl_scan_visitbp(blkptr_t *bp,
347 const zbookmark_t *zb, dnode_phys_t *dnp, arc_buf_t *pbuf,
348 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
349 dmu_tx_t *tx);
350 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
351 dmu_objset_type_t ostype,
352 dnode_phys_t *dnp, arc_buf_t *buf, uint64_t object, dmu_tx_t *tx);
353
354 void
355 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
356 {
357 zio_free(dp->dp_spa, txg, bp);
358 }
359
360 void
361 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
362 {
363 ASSERT(dsl_pool_sync_context(dp));
364 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
365 }
366
367 int
368 dsl_read(zio_t *pio, spa_t *spa, const blkptr_t *bpp, arc_buf_t *pbuf,
369 arc_done_func_t *done, void *private, int priority, int zio_flags,
370 uint32_t *arc_flags, const zbookmark_t *zb)
371 {
372 return (arc_read(pio, spa, bpp, pbuf, done, private,
373 priority, zio_flags, arc_flags, zb));
374 }
375
376 int
377 dsl_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bpp,
378 arc_done_func_t *done, void *private, int priority, int zio_flags,
379 uint32_t *arc_flags, const zbookmark_t *zb)
380 {
381 return (arc_read_nolock(pio, spa, bpp, done, private,
382 priority, zio_flags, arc_flags, zb));
383 }
384
385 static boolean_t
386 bookmark_is_zero(const zbookmark_t *zb)
387 {
388 return (zb->zb_objset == 0 && zb->zb_object == 0 &&
389 zb->zb_level == 0 && zb->zb_blkid == 0);
390 }
391
392 /* dnp is the dnode for zb1->zb_object */
393 static boolean_t
394 bookmark_is_before(const dnode_phys_t *dnp, const zbookmark_t *zb1,
395 const zbookmark_t *zb2)
396 {
397 uint64_t zb1nextL0, zb2thisobj;
398
399 ASSERT(zb1->zb_objset == zb2->zb_objset);
400 ASSERT(zb2->zb_level == 0);
401
402 /*
403 * A bookmark in the deadlist is considered to be after
404 * everything else.
405 */
406 if (zb2->zb_object == DMU_DEADLIST_OBJECT)
407 return (B_TRUE);
408
409 /* The objset_phys_t isn't before anything. */
410 if (dnp == NULL)
411 return (B_FALSE);
412
413 zb1nextL0 = (zb1->zb_blkid + 1) <<
414 ((zb1->zb_level) * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT));
415
416 zb2thisobj = zb2->zb_object ? zb2->zb_object :
417 zb2->zb_blkid << (DNODE_BLOCK_SHIFT - DNODE_SHIFT);
418
419 if (zb1->zb_object == DMU_META_DNODE_OBJECT) {
420 uint64_t nextobj = zb1nextL0 *
421 (dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT) >> DNODE_SHIFT;
422 return (nextobj <= zb2thisobj);
423 }
424
425 if (zb1->zb_object < zb2thisobj)
426 return (B_TRUE);
427 if (zb1->zb_object > zb2thisobj)
428 return (B_FALSE);
429 if (zb2->zb_object == DMU_META_DNODE_OBJECT)
430 return (B_FALSE);
431 return (zb1nextL0 <= zb2->zb_blkid);
432 }
433
434 static uint64_t
435 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
436 {
437 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
438 if (dsl_dataset_is_snapshot(ds))
439 return (MIN(smt, ds->ds_phys->ds_creation_txg));
440 return (smt);
441 }
442
443 static void
444 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
445 {
446 VERIFY(0 == zap_update(scn->scn_dp->dp_meta_objset,
447 DMU_POOL_DIRECTORY_OBJECT,
448 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
449 &scn->scn_phys, tx));
450 }
451
452 static boolean_t
453 dsl_scan_check_pause(dsl_scan_t *scn, const zbookmark_t *zb)
454 {
455 uint64_t elapsed_nanosecs;
456 int mintime;
457
458 /* we never skip user/group accounting objects */
459 if (zb && (int64_t)zb->zb_object < 0)
460 return (B_FALSE);
461
462 if (scn->scn_pausing)
463 return (B_TRUE); /* we're already pausing */
464
465 if (!bookmark_is_zero(&scn->scn_phys.scn_bookmark))
466 return (B_FALSE); /* we're resuming */
467
468 /* We only know how to resume from level-0 blocks. */
469 if (zb && zb->zb_level != 0)
470 return (B_FALSE);
471
472 mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
473 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
474 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
475 if (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
476 (elapsed_nanosecs / MICROSEC > mintime &&
477 txg_sync_waiting(scn->scn_dp)) ||
478 spa_shutting_down(scn->scn_dp->dp_spa)) {
479 if (zb) {
480 dprintf("pausing at bookmark %llx/%llx/%llx/%llx\n",
481 (longlong_t)zb->zb_objset,
482 (longlong_t)zb->zb_object,
483 (longlong_t)zb->zb_level,
484 (longlong_t)zb->zb_blkid);
485 scn->scn_phys.scn_bookmark = *zb;
486 }
487 dprintf("pausing at DDT bookmark %llx/%llx/%llx/%llx\n",
488 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
489 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
490 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
491 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
492 scn->scn_pausing = B_TRUE;
493 return (B_TRUE);
494 }
495 return (B_FALSE);
496 }
497
498 typedef struct zil_scan_arg {
499 dsl_pool_t *zsa_dp;
500 zil_header_t *zsa_zh;
501 } zil_scan_arg_t;
502
503 /* ARGSUSED */
504 static int
505 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
506 {
507 zil_scan_arg_t *zsa = arg;
508 dsl_pool_t *dp = zsa->zsa_dp;
509 dsl_scan_t *scn = dp->dp_scan;
510 zil_header_t *zh = zsa->zsa_zh;
511 zbookmark_t zb;
512
513 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
514 return (0);
515
516 /*
517 * One block ("stubby") can be allocated a long time ago; we
518 * want to visit that one because it has been allocated
519 * (on-disk) even if it hasn't been claimed (even though for
520 * scrub there's nothing to do to it).
521 */
522 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(dp->dp_spa))
523 return (0);
524
525 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
526 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
527
528 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
529 return (0);
530 }
531
532 /* ARGSUSED */
533 static int
534 dsl_scan_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
535 {
536 if (lrc->lrc_txtype == TX_WRITE) {
537 zil_scan_arg_t *zsa = arg;
538 dsl_pool_t *dp = zsa->zsa_dp;
539 dsl_scan_t *scn = dp->dp_scan;
540 zil_header_t *zh = zsa->zsa_zh;
541 lr_write_t *lr = (lr_write_t *)lrc;
542 blkptr_t *bp = &lr->lr_blkptr;
543 zbookmark_t zb;
544
545 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
546 return (0);
547
548 /*
549 * birth can be < claim_txg if this record's txg is
550 * already txg sync'ed (but this log block contains
551 * other records that are not synced)
552 */
553 if (claim_txg == 0 || bp->blk_birth < claim_txg)
554 return (0);
555
556 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
557 lr->lr_foid, ZB_ZIL_LEVEL,
558 lr->lr_offset / BP_GET_LSIZE(bp));
559
560 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
561 }
562 return (0);
563 }
564
565 static void
566 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
567 {
568 uint64_t claim_txg = zh->zh_claim_txg;
569 zil_scan_arg_t zsa = { dp, zh };
570 zilog_t *zilog;
571
572 /*
573 * We only want to visit blocks that have been claimed but not yet
574 * replayed (or, in read-only mode, blocks that *would* be claimed).
575 */
576 if (claim_txg == 0 && spa_writeable(dp->dp_spa))
577 return;
578
579 zilog = zil_alloc(dp->dp_meta_objset, zh);
580
581 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
582 claim_txg);
583
584 zil_free(zilog);
585 }
586
587 /* ARGSUSED */
588 static void
589 dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
590 uint64_t objset, uint64_t object, uint64_t blkid)
591 {
592 zbookmark_t czb;
593 uint32_t flags = ARC_NOWAIT | ARC_PREFETCH;
594
595 if (zfs_no_scrub_prefetch)
596 return;
597
598 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_min_txg ||
599 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE))
600 return;
601
602 SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
603
604 /*
605 * XXX need to make sure all of these arc_read() prefetches are
606 * done before setting xlateall (similar to dsl_read())
607 */
608 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
609 buf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
610 ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
611 }
612
613 static boolean_t
614 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
615 const zbookmark_t *zb)
616 {
617 /*
618 * We never skip over user/group accounting objects (obj<0)
619 */
620 if (!bookmark_is_zero(&scn->scn_phys.scn_bookmark) &&
621 (int64_t)zb->zb_object >= 0) {
622 /*
623 * If we already visited this bp & everything below (in
624 * a prior txg sync), don't bother doing it again.
625 */
626 if (bookmark_is_before(dnp, zb, &scn->scn_phys.scn_bookmark))
627 return (B_TRUE);
628
629 /*
630 * If we found the block we're trying to resume from, or
631 * we went past it to a different object, zero it out to
632 * indicate that it's OK to start checking for pausing
633 * again.
634 */
635 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
636 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
637 dprintf("resuming at %llx/%llx/%llx/%llx\n",
638 (longlong_t)zb->zb_objset,
639 (longlong_t)zb->zb_object,
640 (longlong_t)zb->zb_level,
641 (longlong_t)zb->zb_blkid);
642 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
643 }
644 }
645 return (B_FALSE);
646 }
647
648 /*
649 * Return nonzero on i/o error.
650 * Return new buf to write out in *bufp.
651 */
652 static int
653 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
654 dnode_phys_t *dnp, const blkptr_t *bp,
655 const zbookmark_t *zb, dmu_tx_t *tx, arc_buf_t **bufp)
656 {
657 dsl_pool_t *dp = scn->scn_dp;
658 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
659 int err;
660
661 if (BP_GET_LEVEL(bp) > 0) {
662 uint32_t flags = ARC_WAIT;
663 int i;
664 blkptr_t *cbp;
665 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
666
667 err = arc_read_nolock(NULL, dp->dp_spa, bp,
668 arc_getbuf_func, bufp,
669 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
670 if (err) {
671 scn->scn_phys.scn_errors++;
672 return (err);
673 }
674 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
675 dsl_scan_prefetch(scn, *bufp, cbp, zb->zb_objset,
676 zb->zb_object, zb->zb_blkid * epb + i);
677 }
678 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
679 zbookmark_t czb;
680
681 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
682 zb->zb_level - 1,
683 zb->zb_blkid * epb + i);
684 dsl_scan_visitbp(cbp, &czb, dnp,
685 *bufp, ds, scn, ostype, tx);
686 }
687 } else if (BP_GET_TYPE(bp) == DMU_OT_USERGROUP_USED) {
688 uint32_t flags = ARC_WAIT;
689
690 err = arc_read_nolock(NULL, dp->dp_spa, bp,
691 arc_getbuf_func, bufp,
692 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
693 if (err) {
694 scn->scn_phys.scn_errors++;
695 return (err);
696 }
697 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
698 uint32_t flags = ARC_WAIT;
699 dnode_phys_t *cdnp;
700 int i, j;
701 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
702
703 err = arc_read_nolock(NULL, dp->dp_spa, bp,
704 arc_getbuf_func, bufp,
705 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
706 if (err) {
707 scn->scn_phys.scn_errors++;
708 return (err);
709 }
710 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
711 for (j = 0; j < cdnp->dn_nblkptr; j++) {
712 blkptr_t *cbp = &cdnp->dn_blkptr[j];
713 dsl_scan_prefetch(scn, *bufp, cbp,
714 zb->zb_objset, zb->zb_blkid * epb + i, j);
715 }
716 }
717 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
718 dsl_scan_visitdnode(scn, ds, ostype,
719 cdnp, *bufp, zb->zb_blkid * epb + i, tx);
720 }
721
722 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
723 uint32_t flags = ARC_WAIT;
724 objset_phys_t *osp;
725
726 err = arc_read_nolock(NULL, dp->dp_spa, bp,
727 arc_getbuf_func, bufp,
728 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
729 if (err) {
730 scn->scn_phys.scn_errors++;
731 return (err);
732 }
733
734 osp = (*bufp)->b_data;
735
736 dsl_scan_visitdnode(scn, ds, osp->os_type,
737 &osp->os_meta_dnode, *bufp, DMU_META_DNODE_OBJECT, tx);
738
739 if (OBJSET_BUF_HAS_USERUSED(*bufp)) {
740 /*
741 * We also always visit user/group accounting
742 * objects, and never skip them, even if we are
743 * pausing. This is necessary so that the space
744 * deltas from this txg get integrated.
745 */
746 dsl_scan_visitdnode(scn, ds, osp->os_type,
747 &osp->os_groupused_dnode, *bufp,
748 DMU_GROUPUSED_OBJECT, tx);
749 dsl_scan_visitdnode(scn, ds, osp->os_type,
750 &osp->os_userused_dnode, *bufp,
751 DMU_USERUSED_OBJECT, tx);
752 }
753 }
754
755 return (0);
756 }
757
758 static void
759 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
760 dmu_objset_type_t ostype, dnode_phys_t *dnp, arc_buf_t *buf,
761 uint64_t object, dmu_tx_t *tx)
762 {
763 int j;
764
765 for (j = 0; j < dnp->dn_nblkptr; j++) {
766 zbookmark_t czb;
767
768 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
769 dnp->dn_nlevels - 1, j);
770 dsl_scan_visitbp(&dnp->dn_blkptr[j],
771 &czb, dnp, buf, ds, scn, ostype, tx);
772 }
773
774 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
775 zbookmark_t czb;
776 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
777 0, DMU_SPILL_BLKID);
778 dsl_scan_visitbp(&dnp->dn_spill,
779 &czb, dnp, buf, ds, scn, ostype, tx);
780 }
781 }
782
783 /*
784 * The arguments are in this order because mdb can only print the
785 * first 5; we want them to be useful.
786 */
787 static void
788 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_t *zb,
789 dnode_phys_t *dnp, arc_buf_t *pbuf,
790 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
791 dmu_tx_t *tx)
792 {
793 dsl_pool_t *dp = scn->scn_dp;
794 arc_buf_t *buf = NULL;
795 blkptr_t bp_toread = *bp;
796
797 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
798
799 if (dsl_scan_check_pause(scn, zb))
800 return;
801
802 if (dsl_scan_check_resume(scn, dnp, zb))
803 return;
804
805 if (bp->blk_birth == 0)
806 return;
807
808 scn->scn_visited_this_txg++;
809
810 dprintf_bp(bp,
811 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx buf=%p bp=%p",
812 ds, ds ? ds->ds_object : 0,
813 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
814 pbuf, bp);
815
816 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
817 return;
818
819 if (BP_GET_TYPE(bp) != DMU_OT_USERGROUP_USED) {
820 /*
821 * For non-user-accounting blocks, we need to read the
822 * new bp (from a deleted snapshot, found in
823 * check_existing_xlation). If we used the old bp,
824 * pointers inside this block from before we resumed
825 * would be untranslated.
826 *
827 * For user-accounting blocks, we need to read the old
828 * bp, because we will apply the entire space delta to
829 * it (original untranslated -> translations from
830 * deleted snap -> now).
831 */
832 bp_toread = *bp;
833 }
834
835 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx,
836 &buf) != 0)
837 return;
838
839 /*
840 * If dsl_scan_ddt() has aready visited this block, it will have
841 * already done any translations or scrubbing, so don't call the
842 * callback again.
843 */
844 if (ddt_class_contains(dp->dp_spa,
845 scn->scn_phys.scn_ddt_class_max, bp)) {
846 ASSERT(buf == NULL);
847 return;
848 }
849
850 /*
851 * If this block is from the future (after cur_max_txg), then we
852 * are doing this on behalf of a deleted snapshot, and we will
853 * revisit the future block on the next pass of this dataset.
854 * Don't scan it now unless we need to because something
855 * under it was modified.
856 */
857 if (bp->blk_birth <= scn->scn_phys.scn_cur_max_txg) {
858 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
859 }
860 if (buf)
861 (void) arc_buf_remove_ref(buf, &buf);
862 }
863
864 static void
865 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
866 dmu_tx_t *tx)
867 {
868 zbookmark_t zb;
869
870 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
871 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
872 dsl_scan_visitbp(bp, &zb, NULL, NULL,
873 ds, scn, DMU_OST_NONE, tx);
874
875 dprintf_ds(ds, "finished scan%s", "");
876 }
877
878 void
879 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
880 {
881 dsl_pool_t *dp = ds->ds_dir->dd_pool;
882 dsl_scan_t *scn = dp->dp_scan;
883 uint64_t mintxg;
884
885 if (scn->scn_phys.scn_state != DSS_SCANNING)
886 return;
887
888 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
889 if (dsl_dataset_is_snapshot(ds)) {
890 /* Note, scn_cur_{min,max}_txg stays the same. */
891 scn->scn_phys.scn_bookmark.zb_objset =
892 ds->ds_phys->ds_next_snap_obj;
893 zfs_dbgmsg("destroying ds %llu; currently traversing; "
894 "reset zb_objset to %llu",
895 (u_longlong_t)ds->ds_object,
896 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
897 scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
898 } else {
899 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
900 ZB_DESTROYED_OBJSET, 0, 0, 0);
901 zfs_dbgmsg("destroying ds %llu; currently traversing; "
902 "reset bookmark to -1,0,0,0",
903 (u_longlong_t)ds->ds_object);
904 }
905 } else if (zap_lookup_int_key(dp->dp_meta_objset,
906 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
907 ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
908 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
909 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
910 if (dsl_dataset_is_snapshot(ds)) {
911 /*
912 * We keep the same mintxg; it could be >
913 * ds_creation_txg if the previous snapshot was
914 * deleted too.
915 */
916 VERIFY(zap_add_int_key(dp->dp_meta_objset,
917 scn->scn_phys.scn_queue_obj,
918 ds->ds_phys->ds_next_snap_obj, mintxg, tx) == 0);
919 zfs_dbgmsg("destroying ds %llu; in queue; "
920 "replacing with %llu",
921 (u_longlong_t)ds->ds_object,
922 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
923 } else {
924 zfs_dbgmsg("destroying ds %llu; in queue; removing",
925 (u_longlong_t)ds->ds_object);
926 }
927 } else {
928 zfs_dbgmsg("destroying ds %llu; ignoring",
929 (u_longlong_t)ds->ds_object);
930 }
931
932 /*
933 * dsl_scan_sync() should be called after this, and should sync
934 * out our changed state, but just to be safe, do it here.
935 */
936 dsl_scan_sync_state(scn, tx);
937 }
938
939 void
940 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
941 {
942 dsl_pool_t *dp = ds->ds_dir->dd_pool;
943 dsl_scan_t *scn = dp->dp_scan;
944 uint64_t mintxg;
945
946 if (scn->scn_phys.scn_state != DSS_SCANNING)
947 return;
948
949 ASSERT(ds->ds_phys->ds_prev_snap_obj != 0);
950
951 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
952 scn->scn_phys.scn_bookmark.zb_objset =
953 ds->ds_phys->ds_prev_snap_obj;
954 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
955 "reset zb_objset to %llu",
956 (u_longlong_t)ds->ds_object,
957 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
958 } else if (zap_lookup_int_key(dp->dp_meta_objset,
959 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
960 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
961 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
962 VERIFY(zap_add_int_key(dp->dp_meta_objset,
963 scn->scn_phys.scn_queue_obj,
964 ds->ds_phys->ds_prev_snap_obj, mintxg, tx) == 0);
965 zfs_dbgmsg("snapshotting ds %llu; in queue; "
966 "replacing with %llu",
967 (u_longlong_t)ds->ds_object,
968 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
969 }
970 dsl_scan_sync_state(scn, tx);
971 }
972
973 void
974 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
975 {
976 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
977 dsl_scan_t *scn = dp->dp_scan;
978 uint64_t mintxg;
979
980 if (scn->scn_phys.scn_state != DSS_SCANNING)
981 return;
982
983 if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
984 scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
985 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
986 "reset zb_objset to %llu",
987 (u_longlong_t)ds1->ds_object,
988 (u_longlong_t)ds2->ds_object);
989 } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
990 scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
991 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
992 "reset zb_objset to %llu",
993 (u_longlong_t)ds2->ds_object,
994 (u_longlong_t)ds1->ds_object);
995 }
996
997 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
998 ds1->ds_object, &mintxg) == 0) {
999 int err;
1000
1001 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
1002 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
1003 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1004 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
1005 err = zap_add_int_key(dp->dp_meta_objset,
1006 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
1007 VERIFY(err == 0 || err == EEXIST);
1008 if (err == EEXIST) {
1009 /* Both were there to begin with */
1010 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
1011 scn->scn_phys.scn_queue_obj,
1012 ds1->ds_object, mintxg, tx));
1013 }
1014 zfs_dbgmsg("clone_swap ds %llu; in queue; "
1015 "replacing with %llu",
1016 (u_longlong_t)ds1->ds_object,
1017 (u_longlong_t)ds2->ds_object);
1018 } else if (zap_lookup_int_key(dp->dp_meta_objset,
1019 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
1020 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
1021 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
1022 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1023 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
1024 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
1025 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
1026 zfs_dbgmsg("clone_swap ds %llu; in queue; "
1027 "replacing with %llu",
1028 (u_longlong_t)ds2->ds_object,
1029 (u_longlong_t)ds1->ds_object);
1030 }
1031
1032 dsl_scan_sync_state(scn, tx);
1033 }
1034
1035 struct enqueue_clones_arg {
1036 dmu_tx_t *tx;
1037 uint64_t originobj;
1038 };
1039
1040 /* ARGSUSED */
1041 static int
1042 enqueue_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
1043 {
1044 struct enqueue_clones_arg *eca = arg;
1045 dsl_dataset_t *ds;
1046 int err;
1047 dsl_pool_t *dp = spa->spa_dsl_pool;
1048 dsl_scan_t *scn = dp->dp_scan;
1049
1050 err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
1051 if (err)
1052 return (err);
1053
1054 if (ds->ds_dir->dd_phys->dd_origin_obj == eca->originobj) {
1055 while (ds->ds_phys->ds_prev_snap_obj != eca->originobj) {
1056 dsl_dataset_t *prev;
1057 err = dsl_dataset_hold_obj(dp,
1058 ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
1059
1060 dsl_dataset_rele(ds, FTAG);
1061 if (err)
1062 return (err);
1063 ds = prev;
1064 }
1065 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1066 scn->scn_phys.scn_queue_obj, ds->ds_object,
1067 ds->ds_phys->ds_prev_snap_txg, eca->tx) == 0);
1068 }
1069 dsl_dataset_rele(ds, FTAG);
1070 return (0);
1071 }
1072
1073 static void
1074 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
1075 {
1076 dsl_pool_t *dp = scn->scn_dp;
1077 dsl_dataset_t *ds;
1078 objset_t *os;
1079
1080 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1081
1082 if (dmu_objset_from_ds(ds, &os))
1083 goto out;
1084
1085 /*
1086 * Only the ZIL in the head (non-snapshot) is valid. Even though
1087 * snapshots can have ZIL block pointers (which may be the same
1088 * BP as in the head), they must be ignored. So we traverse the
1089 * ZIL here, rather than in scan_recurse(), because the regular
1090 * snapshot block-sharing rules don't apply to it.
1091 */
1092 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !dsl_dataset_is_snapshot(ds))
1093 dsl_scan_zil(dp, &os->os_zil_header);
1094
1095 /*
1096 * Iterate over the bps in this ds.
1097 */
1098 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1099 dsl_scan_visit_rootbp(scn, ds, &ds->ds_phys->ds_bp, tx);
1100
1101 char *dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
1102 dsl_dataset_name(ds, dsname);
1103 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1104 "pausing=%u",
1105 (longlong_t)dsobj, dsname,
1106 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1107 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1108 (int)scn->scn_pausing);
1109 kmem_free(dsname, ZFS_MAXNAMELEN);
1110
1111 if (scn->scn_pausing)
1112 goto out;
1113
1114 /*
1115 * We've finished this pass over this dataset.
1116 */
1117
1118 /*
1119 * If we did not completely visit this dataset, do another pass.
1120 */
1121 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1122 zfs_dbgmsg("incomplete pass; visiting again");
1123 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1124 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1125 scn->scn_phys.scn_queue_obj, ds->ds_object,
1126 scn->scn_phys.scn_cur_max_txg, tx) == 0);
1127 goto out;
1128 }
1129
1130 /*
1131 * Add descendent datasets to work queue.
1132 */
1133 if (ds->ds_phys->ds_next_snap_obj != 0) {
1134 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1135 scn->scn_phys.scn_queue_obj, ds->ds_phys->ds_next_snap_obj,
1136 ds->ds_phys->ds_creation_txg, tx) == 0);
1137 }
1138 if (ds->ds_phys->ds_num_children > 1) {
1139 boolean_t usenext = B_FALSE;
1140 if (ds->ds_phys->ds_next_clones_obj != 0) {
1141 uint64_t count;
1142 /*
1143 * A bug in a previous version of the code could
1144 * cause upgrade_clones_cb() to not set
1145 * ds_next_snap_obj when it should, leading to a
1146 * missing entry. Therefore we can only use the
1147 * next_clones_obj when its count is correct.
1148 */
1149 int err = zap_count(dp->dp_meta_objset,
1150 ds->ds_phys->ds_next_clones_obj, &count);
1151 if (err == 0 &&
1152 count == ds->ds_phys->ds_num_children - 1)
1153 usenext = B_TRUE;
1154 }
1155
1156 if (usenext) {
1157 VERIFY(zap_join_key(dp->dp_meta_objset,
1158 ds->ds_phys->ds_next_clones_obj,
1159 scn->scn_phys.scn_queue_obj,
1160 ds->ds_phys->ds_creation_txg, tx) == 0);
1161 } else {
1162 struct enqueue_clones_arg eca;
1163 eca.tx = tx;
1164 eca.originobj = ds->ds_object;
1165
1166 (void) dmu_objset_find_spa(ds->ds_dir->dd_pool->dp_spa,
1167 NULL, enqueue_clones_cb, &eca, DS_FIND_CHILDREN);
1168 }
1169 }
1170
1171 out:
1172 dsl_dataset_rele(ds, FTAG);
1173 }
1174
1175 /* ARGSUSED */
1176 static int
1177 enqueue_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
1178 {
1179 dmu_tx_t *tx = arg;
1180 dsl_dataset_t *ds;
1181 int err;
1182 dsl_pool_t *dp = spa->spa_dsl_pool;
1183 dsl_scan_t *scn = dp->dp_scan;
1184
1185 err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
1186 if (err)
1187 return (err);
1188
1189 while (ds->ds_phys->ds_prev_snap_obj != 0) {
1190 dsl_dataset_t *prev;
1191 err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
1192 FTAG, &prev);
1193 if (err) {
1194 dsl_dataset_rele(ds, FTAG);
1195 return (err);
1196 }
1197
1198 /*
1199 * If this is a clone, we don't need to worry about it for now.
1200 */
1201 if (prev->ds_phys->ds_next_snap_obj != ds->ds_object) {
1202 dsl_dataset_rele(ds, FTAG);
1203 dsl_dataset_rele(prev, FTAG);
1204 return (0);
1205 }
1206 dsl_dataset_rele(ds, FTAG);
1207 ds = prev;
1208 }
1209
1210 VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1211 ds->ds_object, ds->ds_phys->ds_prev_snap_txg, tx) == 0);
1212 dsl_dataset_rele(ds, FTAG);
1213 return (0);
1214 }
1215
1216 /*
1217 * Scrub/dedup interaction.
1218 *
1219 * If there are N references to a deduped block, we don't want to scrub it
1220 * N times -- ideally, we should scrub it exactly once.
1221 *
1222 * We leverage the fact that the dde's replication class (enum ddt_class)
1223 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1224 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1225 *
1226 * To prevent excess scrubbing, the scrub begins by walking the DDT
1227 * to find all blocks with refcnt > 1, and scrubs each of these once.
1228 * Since there are two replication classes which contain blocks with
1229 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1230 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1231 *
1232 * There would be nothing more to say if a block's refcnt couldn't change
1233 * during a scrub, but of course it can so we must account for changes
1234 * in a block's replication class.
1235 *
1236 * Here's an example of what can occur:
1237 *
1238 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
1239 * when visited during the top-down scrub phase, it will be scrubbed twice.
1240 * This negates our scrub optimization, but is otherwise harmless.
1241 *
1242 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1243 * on each visit during the top-down scrub phase, it will never be scrubbed.
1244 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1245 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1246 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1247 * while a scrub is in progress, it scrubs the block right then.
1248 */
1249 static void
1250 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1251 {
1252 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1253 ddt_entry_t dde = { 0 };
1254 int error;
1255 uint64_t n = 0;
1256
1257 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1258 ddt_t *ddt;
1259
1260 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1261 break;
1262 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1263 (longlong_t)ddb->ddb_class,
1264 (longlong_t)ddb->ddb_type,
1265 (longlong_t)ddb->ddb_checksum,
1266 (longlong_t)ddb->ddb_cursor);
1267
1268 /* There should be no pending changes to the dedup table */
1269 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1270 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
1271
1272 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1273 n++;
1274
1275 if (dsl_scan_check_pause(scn, NULL))
1276 break;
1277 }
1278
1279 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; pausing=%u",
1280 (longlong_t)n, (int)scn->scn_phys.scn_ddt_class_max,
1281 (int)scn->scn_pausing);
1282
1283 ASSERT(error == 0 || error == ENOENT);
1284 ASSERT(error != ENOENT ||
1285 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1286 }
1287
1288 /* ARGSUSED */
1289 void
1290 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1291 ddt_entry_t *dde, dmu_tx_t *tx)
1292 {
1293 const ddt_key_t *ddk = &dde->dde_key;
1294 ddt_phys_t *ddp = dde->dde_phys;
1295 blkptr_t bp;
1296 zbookmark_t zb = { 0 };
1297
1298 if (scn->scn_phys.scn_state != DSS_SCANNING)
1299 return;
1300
1301 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1302 if (ddp->ddp_phys_birth == 0 ||
1303 ddp->ddp_phys_birth > scn->scn_phys.scn_cur_max_txg)
1304 continue;
1305 ddt_bp_create(checksum, ddk, ddp, &bp);
1306
1307 scn->scn_visited_this_txg++;
1308 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1309 }
1310 }
1311
1312 static void
1313 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1314 {
1315 dsl_pool_t *dp = scn->scn_dp;
1316 zap_cursor_t zc;
1317 zap_attribute_t za;
1318
1319 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1320 scn->scn_phys.scn_ddt_class_max) {
1321 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1322 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1323 dsl_scan_ddt(scn, tx);
1324 if (scn->scn_pausing)
1325 return;
1326 }
1327
1328 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1329 /* First do the MOS & ORIGIN */
1330
1331 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1332 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1333 dsl_scan_visit_rootbp(scn, NULL,
1334 &dp->dp_meta_rootbp, tx);
1335 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1336 if (scn->scn_pausing)
1337 return;
1338
1339 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1340 VERIFY(0 == dmu_objset_find_spa(dp->dp_spa,
1341 NULL, enqueue_cb, tx, DS_FIND_CHILDREN));
1342 } else {
1343 dsl_scan_visitds(scn,
1344 dp->dp_origin_snap->ds_object, tx);
1345 }
1346 ASSERT(!scn->scn_pausing);
1347 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
1348 ZB_DESTROYED_OBJSET) {
1349 /*
1350 * If we were paused, continue from here. Note if the
1351 * ds we were paused on was deleted, the zb_objset may
1352 * be -1, so we will skip this and find a new objset
1353 * below.
1354 */
1355 dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
1356 if (scn->scn_pausing)
1357 return;
1358 }
1359
1360 /*
1361 * In case we were paused right at the end of the ds, zero the
1362 * bookmark so we don't think that we're still trying to resume.
1363 */
1364 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_t));
1365
1366 /* keep pulling things out of the zap-object-as-queue */
1367 while (zap_cursor_init(&zc, dp->dp_meta_objset,
1368 scn->scn_phys.scn_queue_obj),
1369 zap_cursor_retrieve(&zc, &za) == 0) {
1370 dsl_dataset_t *ds;
1371 uint64_t dsobj;
1372
1373 dsobj = strtonum(za.za_name, NULL);
1374 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1375 scn->scn_phys.scn_queue_obj, dsobj, tx));
1376
1377 /* Set up min/max txg */
1378 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1379 if (za.za_first_integer != 0) {
1380 scn->scn_phys.scn_cur_min_txg =
1381 MAX(scn->scn_phys.scn_min_txg,
1382 za.za_first_integer);
1383 } else {
1384 scn->scn_phys.scn_cur_min_txg =
1385 MAX(scn->scn_phys.scn_min_txg,
1386 ds->ds_phys->ds_prev_snap_txg);
1387 }
1388 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
1389 dsl_dataset_rele(ds, FTAG);
1390
1391 dsl_scan_visitds(scn, dsobj, tx);
1392 zap_cursor_fini(&zc);
1393 if (scn->scn_pausing)
1394 return;
1395 }
1396 zap_cursor_fini(&zc);
1397 }
1398
1399 static int
1400 dsl_scan_free_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1401 {
1402 dsl_scan_t *scn = arg;
1403 uint64_t elapsed_nanosecs;
1404
1405 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
1406
1407 if (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
1408 (elapsed_nanosecs / MICROSEC > zfs_free_min_time_ms &&
1409 txg_sync_waiting(scn->scn_dp)) ||
1410 spa_shutting_down(scn->scn_dp->dp_spa))
1411 return (ERESTART);
1412
1413 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
1414 dmu_tx_get_txg(tx), bp, 0));
1415 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
1416 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
1417 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
1418 scn->scn_visited_this_txg++;
1419 return (0);
1420 }
1421
1422 boolean_t
1423 dsl_scan_active(dsl_scan_t *scn)
1424 {
1425 spa_t *spa = scn->scn_dp->dp_spa;
1426 uint64_t used = 0, comp, uncomp;
1427
1428 if (spa->spa_load_state != SPA_LOAD_NONE)
1429 return (B_FALSE);
1430 if (spa_shutting_down(spa))
1431 return (B_FALSE);
1432
1433 if (scn->scn_phys.scn_state == DSS_SCANNING)
1434 return (B_TRUE);
1435
1436 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1437 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
1438 &used, &comp, &uncomp);
1439 }
1440 return (used != 0);
1441 }
1442
1443 void
1444 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
1445 {
1446 dsl_scan_t *scn = dp->dp_scan;
1447 spa_t *spa = dp->dp_spa;
1448 int err;
1449
1450 /*
1451 * Check for scn_restart_txg before checking spa_load_state, so
1452 * that we can restart an old-style scan while the pool is being
1453 * imported (see dsl_scan_init).
1454 */
1455 if (scn->scn_restart_txg != 0 &&
1456 scn->scn_restart_txg <= tx->tx_txg) {
1457 pool_scan_func_t func = POOL_SCAN_SCRUB;
1458 dsl_scan_done(scn, B_FALSE, tx);
1459 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
1460 func = POOL_SCAN_RESILVER;
1461 zfs_dbgmsg("restarting scan func=%u txg=%llu",
1462 func, tx->tx_txg);
1463 dsl_scan_setup_sync(scn, &func, tx);
1464 }
1465
1466 if (!dsl_scan_active(scn) ||
1467 spa_sync_pass(dp->dp_spa) > 1)
1468 return;
1469
1470 scn->scn_visited_this_txg = 0;
1471 scn->scn_pausing = B_FALSE;
1472 scn->scn_sync_start_time = gethrtime();
1473 spa->spa_scrub_active = B_TRUE;
1474
1475 /*
1476 * First process the free list. If we pause the free, don't do
1477 * any scanning. This ensures that there is no free list when
1478 * we are scanning, so the scan code doesn't have to worry about
1479 * traversing it.
1480 */
1481 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1482 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1483 NULL, ZIO_FLAG_MUSTSUCCEED);
1484 err = bpobj_iterate(&dp->dp_free_bpobj,
1485 dsl_scan_free_cb, scn, tx);
1486 VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
1487 if (scn->scn_visited_this_txg) {
1488 zfs_dbgmsg("freed %llu blocks in %llums from "
1489 "free_bpobj txg %llu",
1490 (longlong_t)scn->scn_visited_this_txg,
1491 (longlong_t)
1492 (gethrtime() - scn->scn_sync_start_time) / MICROSEC,
1493 (longlong_t)tx->tx_txg);
1494 scn->scn_visited_this_txg = 0;
1495 /*
1496 * Re-sync the ddt so that we can further modify
1497 * it when doing bprewrite.
1498 */
1499 ddt_sync(spa, tx->tx_txg);
1500 }
1501 if (err == ERESTART)
1502 return;
1503 }
1504
1505 if (scn->scn_phys.scn_state != DSS_SCANNING)
1506 return;
1507
1508 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1509 scn->scn_phys.scn_ddt_class_max) {
1510 zfs_dbgmsg("doing scan sync txg %llu; "
1511 "ddt bm=%llu/%llu/%llu/%llx",
1512 (longlong_t)tx->tx_txg,
1513 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1514 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1515 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1516 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1517 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
1518 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
1519 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
1520 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
1521 } else {
1522 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
1523 (longlong_t)tx->tx_txg,
1524 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
1525 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
1526 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
1527 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
1528 }
1529
1530 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1531 NULL, ZIO_FLAG_CANFAIL);
1532 dsl_scan_visit(scn, tx);
1533 (void) zio_wait(scn->scn_zio_root);
1534 scn->scn_zio_root = NULL;
1535
1536 zfs_dbgmsg("visited %llu blocks in %llums",
1537 (longlong_t)scn->scn_visited_this_txg,
1538 (longlong_t)(gethrtime() - scn->scn_sync_start_time) / MICROSEC);
1539
1540 if (!scn->scn_pausing) {
1541 /* finished with scan. */
1542 zfs_dbgmsg("finished scan txg %llu", (longlong_t)tx->tx_txg);
1543 dsl_scan_done(scn, B_TRUE, tx);
1544 }
1545
1546 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
1547 mutex_enter(&spa->spa_scrub_lock);
1548 while (spa->spa_scrub_inflight > 0) {
1549 cv_wait(&spa->spa_scrub_io_cv,
1550 &spa->spa_scrub_lock);
1551 }
1552 mutex_exit(&spa->spa_scrub_lock);
1553 }
1554
1555 dsl_scan_sync_state(scn, tx);
1556 }
1557
1558 /*
1559 * This will start a new scan, or restart an existing one.
1560 */
1561 void
1562 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
1563 {
1564 if (txg == 0) {
1565 dmu_tx_t *tx;
1566 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1567 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1568
1569 txg = dmu_tx_get_txg(tx);
1570 dp->dp_scan->scn_restart_txg = txg;
1571 dmu_tx_commit(tx);
1572 } else {
1573 dp->dp_scan->scn_restart_txg = txg;
1574 }
1575 zfs_dbgmsg("restarting resilver txg=%llu", txg);
1576 }
1577
1578 boolean_t
1579 dsl_scan_resilvering(dsl_pool_t *dp)
1580 {
1581 return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
1582 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
1583 }
1584
1585 /*
1586 * scrub consumers
1587 */
1588
1589 static void
1590 count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
1591 {
1592 int i;
1593
1594 /*
1595 * If we resume after a reboot, zab will be NULL; don't record
1596 * incomplete stats in that case.
1597 */
1598 if (zab == NULL)
1599 return;
1600
1601 for (i = 0; i < 4; i++) {
1602 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
1603 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
1604 zfs_blkstat_t *zb = &zab->zab_type[l][t];
1605 int equal;
1606
1607 zb->zb_count++;
1608 zb->zb_asize += BP_GET_ASIZE(bp);
1609 zb->zb_lsize += BP_GET_LSIZE(bp);
1610 zb->zb_psize += BP_GET_PSIZE(bp);
1611 zb->zb_gangs += BP_COUNT_GANG(bp);
1612
1613 switch (BP_GET_NDVAS(bp)) {
1614 case 2:
1615 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1616 DVA_GET_VDEV(&bp->blk_dva[1]))
1617 zb->zb_ditto_2_of_2_samevdev++;
1618 break;
1619 case 3:
1620 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1621 DVA_GET_VDEV(&bp->blk_dva[1])) +
1622 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1623 DVA_GET_VDEV(&bp->blk_dva[2])) +
1624 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
1625 DVA_GET_VDEV(&bp->blk_dva[2]));
1626 if (equal == 1)
1627 zb->zb_ditto_2_of_3_samevdev++;
1628 else if (equal == 3)
1629 zb->zb_ditto_3_of_3_samevdev++;
1630 break;
1631 }
1632 }
1633 }
1634
1635 static void
1636 dsl_scan_scrub_done(zio_t *zio)
1637 {
1638 spa_t *spa = zio->io_spa;
1639
1640 zio_data_buf_free(zio->io_data, zio->io_size);
1641
1642 mutex_enter(&spa->spa_scrub_lock);
1643 spa->spa_scrub_inflight--;
1644 cv_broadcast(&spa->spa_scrub_io_cv);
1645
1646 if (zio->io_error && (zio->io_error != ECKSUM ||
1647 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
1648 spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
1649 }
1650 mutex_exit(&spa->spa_scrub_lock);
1651 }
1652
1653 static int
1654 dsl_scan_scrub_cb(dsl_pool_t *dp,
1655 const blkptr_t *bp, const zbookmark_t *zb)
1656 {
1657 dsl_scan_t *scn = dp->dp_scan;
1658 size_t size = BP_GET_PSIZE(bp);
1659 spa_t *spa = dp->dp_spa;
1660 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
1661 boolean_t needs_io;
1662 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
1663 int zio_priority;
1664 int scan_delay = 0;
1665
1666 if (phys_birth <= scn->scn_phys.scn_min_txg ||
1667 phys_birth >= scn->scn_phys.scn_max_txg)
1668 return (0);
1669
1670 count_block(dp->dp_blkstats, bp);
1671
1672 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
1673 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
1674 zio_flags |= ZIO_FLAG_SCRUB;
1675 zio_priority = ZIO_PRIORITY_SCRUB;
1676 needs_io = B_TRUE;
1677 scan_delay = zfs_scrub_delay;
1678 } else if (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) {
1679 zio_flags |= ZIO_FLAG_RESILVER;
1680 zio_priority = ZIO_PRIORITY_RESILVER;
1681 needs_io = B_FALSE;
1682 scan_delay = zfs_resilver_delay;
1683 }
1684
1685 /* If it's an intent log block, failure is expected. */
1686 if (zb->zb_level == ZB_ZIL_LEVEL)
1687 zio_flags |= ZIO_FLAG_SPECULATIVE;
1688
1689 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
1690 vdev_t *vd = vdev_lookup_top(spa,
1691 DVA_GET_VDEV(&bp->blk_dva[d]));
1692
1693 /*
1694 * Keep track of how much data we've examined so that
1695 * zpool(1M) status can make useful progress reports.
1696 */
1697 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
1698 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
1699
1700 /* if it's a resilver, this may not be in the target range */
1701 if (!needs_io) {
1702 if (DVA_GET_GANG(&bp->blk_dva[d])) {
1703 /*
1704 * Gang members may be spread across multiple
1705 * vdevs, so the best estimate we have is the
1706 * scrub range, which has already been checked.
1707 * XXX -- it would be better to change our
1708 * allocation policy to ensure that all
1709 * gang members reside on the same vdev.
1710 */
1711 needs_io = B_TRUE;
1712 } else {
1713 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
1714 phys_birth, 1);
1715 }
1716 }
1717 }
1718
1719 if (needs_io && !zfs_no_scrub_io) {
1720 vdev_t *rvd = spa->spa_root_vdev;
1721 uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
1722 void *data = zio_data_buf_alloc(size);
1723
1724 mutex_enter(&spa->spa_scrub_lock);
1725 while (spa->spa_scrub_inflight >= maxinflight)
1726 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1727 spa->spa_scrub_inflight++;
1728 mutex_exit(&spa->spa_scrub_lock);
1729
1730 /*
1731 * If we're seeing recent (zfs_scan_idle) "important" I/Os
1732 * then throttle our workload to limit the impact of a scan.
1733 */
1734 if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
1735 delay(scan_delay);
1736
1737 zio_nowait(zio_read(NULL, spa, bp, data, size,
1738 dsl_scan_scrub_done, NULL, zio_priority,
1739 zio_flags, zb));
1740 }
1741
1742 /* do not relocate this block */
1743 return (0);
1744 }
1745
1746 int
1747 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
1748 {
1749 spa_t *spa = dp->dp_spa;
1750
1751 /*
1752 * Purge all vdev caches and probe all devices. We do this here
1753 * rather than in sync context because this requires a writer lock
1754 * on the spa_config lock, which we can't do from sync context. The
1755 * spa_scrub_reopen flag indicates that vdev_open() should not
1756 * attempt to start another scrub.
1757 */
1758 spa_vdev_state_enter(spa, SCL_NONE);
1759 spa->spa_scrub_reopen = B_TRUE;
1760 vdev_reopen(spa->spa_root_vdev);
1761 spa->spa_scrub_reopen = B_FALSE;
1762 (void) spa_vdev_state_exit(spa, NULL, 0);
1763
1764 return (dsl_sync_task_do(dp, dsl_scan_setup_check,
1765 dsl_scan_setup_sync, dp->dp_scan, &func, 0));
1766 }