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) 2012 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 dsl_syncfunc_t dsl_scan_cancel_sync;
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 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
99 "scrub_func", sizeof (uint64_t), 1, &f);
100 if (err == 0) {
101 /*
102 * There was an old-style scrub in progress. Restart a
103 * new-style scrub from the beginning.
104 */
105 scn->scn_restart_txg = txg;
106 zfs_dbgmsg("old-style scrub was in progress; "
107 "restarting new-style scrub in txg %llu",
108 scn->scn_restart_txg);
109
110 /*
111 * Load the queue obj from the old location so that it
112 * can be freed by dsl_scan_done().
113 */
114 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
115 "scrub_queue", sizeof (uint64_t), 1,
116 &scn->scn_phys.scn_queue_obj);
117 } else {
118 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
119 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
120 &scn->scn_phys);
121 if (err == ENOENT)
122 return (0);
123 else if (err)
124 return (err);
125
126 if (scn->scn_phys.scn_state == DSS_SCANNING &&
127 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
128 /*
129 * A new-type scrub was in progress on an old
130 * pool, and the pool was accessed by old
131 * software. Restart from the beginning, since
132 * the old software may have changed the pool in
133 * the meantime.
134 */
135 scn->scn_restart_txg = txg;
136 zfs_dbgmsg("new-style scrub was modified "
137 "by old software; restarting in txg %llu",
138 scn->scn_restart_txg);
139 }
140 }
141
142 spa_scan_stat_init(spa);
143 return (0);
144 }
145
146 void
147 dsl_scan_fini(dsl_pool_t *dp)
148 {
149 if (dp->dp_scan) {
150 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
151 dp->dp_scan = NULL;
152 }
153 }
154
155 /* ARGSUSED */
156 static int
157 dsl_scan_setup_check(void *arg1, void *arg2, dmu_tx_t *tx)
158 {
159 dsl_scan_t *scn = arg1;
160
161 if (scn->scn_phys.scn_state == DSS_SCANNING)
162 return (EBUSY);
163
164 return (0);
165 }
166
167 /* ARGSUSED */
168 static void
169 dsl_scan_setup_sync(void *arg1, void *arg2, dmu_tx_t *tx)
170 {
171 dsl_scan_t *scn = arg1;
172 pool_scan_func_t *funcp = arg2;
173 dmu_object_type_t ot = 0;
174 dsl_pool_t *dp = scn->scn_dp;
175 spa_t *spa = dp->dp_spa;
176
177 ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
178 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
179 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
180 scn->scn_phys.scn_func = *funcp;
181 scn->scn_phys.scn_state = DSS_SCANNING;
182 scn->scn_phys.scn_min_txg = 0;
183 scn->scn_phys.scn_max_txg = tx->tx_txg;
184 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
185 scn->scn_phys.scn_start_time = gethrestime_sec();
186 scn->scn_phys.scn_errors = 0;
187 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
188 scn->scn_restart_txg = 0;
189 spa_scan_stat_init(spa);
190
191 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
192 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
193
194 /* rewrite all disk labels */
195 vdev_config_dirty(spa->spa_root_vdev);
196
197 if (vdev_resilver_needed(spa->spa_root_vdev,
198 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
199 spa_event_notify(spa, NULL, ESC_ZFS_RESILVER_START);
200 } else {
201 spa_event_notify(spa, NULL, ESC_ZFS_SCRUB_START);
202 }
203
204 spa->spa_scrub_started = B_TRUE;
205 /*
206 * If this is an incremental scrub, limit the DDT scrub phase
207 * to just the auto-ditto class (for correctness); the rest
208 * of the scrub should go faster using top-down pruning.
209 */
210 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
211 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
212
213 }
214
215 /* back to the generic stuff */
216
217 if (dp->dp_blkstats == NULL) {
218 dp->dp_blkstats =
219 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
220 }
221 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
222
223 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
224 ot = DMU_OT_ZAP_OTHER;
225
226 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
227 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
228
229 dsl_scan_sync_state(scn, tx);
230
231 spa_history_log_internal(spa, "scan setup", tx,
232 "func=%u mintxg=%llu maxtxg=%llu",
233 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
234 }
235
236 /* ARGSUSED */
237 static void
238 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
239 {
240 static const char *old_names[] = {
241 "scrub_bookmark",
242 "scrub_ddt_bookmark",
243 "scrub_ddt_class_max",
244 "scrub_queue",
245 "scrub_min_txg",
246 "scrub_max_txg",
247 "scrub_func",
248 "scrub_errors",
249 NULL
250 };
251
252 dsl_pool_t *dp = scn->scn_dp;
253 spa_t *spa = dp->dp_spa;
254 int i;
255
256 /* Remove any remnants of an old-style scrub. */
257 for (i = 0; old_names[i]; i++) {
258 (void) zap_remove(dp->dp_meta_objset,
259 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
260 }
261
262 if (scn->scn_phys.scn_queue_obj != 0) {
263 VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
264 scn->scn_phys.scn_queue_obj, tx));
265 scn->scn_phys.scn_queue_obj = 0;
266 }
267
268 /*
269 * If we were "restarted" from a stopped state, don't bother
270 * with anything else.
271 */
272 if (scn->scn_phys.scn_state != DSS_SCANNING)
273 return;
274
275 if (complete)
276 scn->scn_phys.scn_state = DSS_FINISHED;
277 else
278 scn->scn_phys.scn_state = DSS_CANCELED;
279
280 spa_history_log_internal(spa, "scan done", tx,
281 "complete=%u", complete);
282
283 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
284 mutex_enter(&spa->spa_scrub_lock);
285 while (spa->spa_scrub_inflight > 0) {
286 cv_wait(&spa->spa_scrub_io_cv,
287 &spa->spa_scrub_lock);
288 }
289 mutex_exit(&spa->spa_scrub_lock);
290 spa->spa_scrub_started = B_FALSE;
291 spa->spa_scrub_active = B_FALSE;
292
293 /*
294 * If the scrub/resilver completed, update all DTLs to
295 * reflect this. Whether it succeeded or not, vacate
296 * all temporary scrub DTLs.
297 */
298 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
299 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
300 if (complete) {
301 spa_event_notify(spa, NULL, scn->scn_phys.scn_min_txg ?
302 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
303 }
304 spa_errlog_rotate(spa);
305
306 /*
307 * We may have finished replacing a device.
308 * Let the async thread assess this and handle the detach.
309 */
310 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
311 }
312
313 scn->scn_phys.scn_end_time = gethrestime_sec();
314 }
315
316 /* ARGSUSED */
317 static int
318 dsl_scan_cancel_check(void *arg1, void *arg2, dmu_tx_t *tx)
319 {
320 dsl_scan_t *scn = arg1;
321
322 if (scn->scn_phys.scn_state != DSS_SCANNING)
323 return (ENOENT);
324 return (0);
325 }
326
327 /* ARGSUSED */
328 static void
329 dsl_scan_cancel_sync(void *arg1, void *arg2, dmu_tx_t *tx)
330 {
331 dsl_scan_t *scn = arg1;
332
333 dsl_scan_done(scn, B_FALSE, tx);
334 dsl_scan_sync_state(scn, tx);
335 }
336
337 int
338 dsl_scan_cancel(dsl_pool_t *dp)
339 {
340 boolean_t complete = B_FALSE;
341 int err;
342
343 err = dsl_sync_task_do(dp, dsl_scan_cancel_check,
344 dsl_scan_cancel_sync, dp->dp_scan, &complete, 3);
345 return (err);
346 }
347
348 static void dsl_scan_visitbp(blkptr_t *bp,
349 const zbookmark_t *zb, dnode_phys_t *dnp, arc_buf_t *pbuf,
350 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
351 dmu_tx_t *tx);
352 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
353 dmu_objset_type_t ostype,
354 dnode_phys_t *dnp, arc_buf_t *buf, uint64_t object, dmu_tx_t *tx);
355
356 void
357 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
358 {
359 zio_free(dp->dp_spa, txg, bp);
360 }
361
362 void
363 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
364 {
365 ASSERT(dsl_pool_sync_context(dp));
366 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
367 }
368
369 int
370 dsl_read(zio_t *pio, spa_t *spa, const blkptr_t *bpp, arc_buf_t *pbuf,
371 arc_done_func_t *done, void *private, int priority, int zio_flags,
372 uint32_t *arc_flags, const zbookmark_t *zb)
373 {
374 return (arc_read(pio, spa, bpp, pbuf, done, private,
375 priority, zio_flags, arc_flags, zb));
376 }
377
378 int
379 dsl_read_nolock(zio_t *pio, spa_t *spa, const blkptr_t *bpp,
380 arc_done_func_t *done, void *private, int priority, int zio_flags,
381 uint32_t *arc_flags, const zbookmark_t *zb)
382 {
383 return (arc_read_nolock(pio, spa, bpp, done, private,
384 priority, zio_flags, arc_flags, zb));
385 }
386
387 static uint64_t
388 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
389 {
390 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
391 if (dsl_dataset_is_snapshot(ds))
392 return (MIN(smt, ds->ds_phys->ds_creation_txg));
393 return (smt);
394 }
395
396 static void
397 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
398 {
399 VERIFY(0 == zap_update(scn->scn_dp->dp_meta_objset,
400 DMU_POOL_DIRECTORY_OBJECT,
401 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
402 &scn->scn_phys, tx));
403 }
404
405 static boolean_t
406 dsl_scan_check_pause(dsl_scan_t *scn, const zbookmark_t *zb)
407 {
408 uint64_t elapsed_nanosecs;
409 int mintime;
410
411 /* we never skip user/group accounting objects */
412 if (zb && (int64_t)zb->zb_object < 0)
413 return (B_FALSE);
414
415 if (scn->scn_pausing)
416 return (B_TRUE); /* we're already pausing */
417
418 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
419 return (B_FALSE); /* we're resuming */
420
421 /* We only know how to resume from level-0 blocks. */
422 if (zb && zb->zb_level != 0)
423 return (B_FALSE);
424
425 mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
426 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
427 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
428 if (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
429 (elapsed_nanosecs / MICROSEC > mintime &&
430 txg_sync_waiting(scn->scn_dp)) ||
431 spa_shutting_down(scn->scn_dp->dp_spa)) {
432 if (zb) {
433 dprintf("pausing at bookmark %llx/%llx/%llx/%llx\n",
434 (longlong_t)zb->zb_objset,
435 (longlong_t)zb->zb_object,
436 (longlong_t)zb->zb_level,
437 (longlong_t)zb->zb_blkid);
438 scn->scn_phys.scn_bookmark = *zb;
439 }
440 dprintf("pausing at DDT bookmark %llx/%llx/%llx/%llx\n",
441 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
442 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
443 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
444 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
445 scn->scn_pausing = B_TRUE;
446 return (B_TRUE);
447 }
448 return (B_FALSE);
449 }
450
451 typedef struct zil_scan_arg {
452 dsl_pool_t *zsa_dp;
453 zil_header_t *zsa_zh;
454 } zil_scan_arg_t;
455
456 /* ARGSUSED */
457 static int
458 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
459 {
460 zil_scan_arg_t *zsa = arg;
461 dsl_pool_t *dp = zsa->zsa_dp;
462 dsl_scan_t *scn = dp->dp_scan;
463 zil_header_t *zh = zsa->zsa_zh;
464 zbookmark_t zb;
465
466 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
467 return (0);
468
469 /*
470 * One block ("stubby") can be allocated a long time ago; we
471 * want to visit that one because it has been allocated
472 * (on-disk) even if it hasn't been claimed (even though for
473 * scrub there's nothing to do to it).
474 */
475 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(dp->dp_spa))
476 return (0);
477
478 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
479 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
480
481 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
482 return (0);
483 }
484
485 /* ARGSUSED */
486 static int
487 dsl_scan_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
488 {
489 if (lrc->lrc_txtype == TX_WRITE) {
490 zil_scan_arg_t *zsa = arg;
491 dsl_pool_t *dp = zsa->zsa_dp;
492 dsl_scan_t *scn = dp->dp_scan;
493 zil_header_t *zh = zsa->zsa_zh;
494 lr_write_t *lr = (lr_write_t *)lrc;
495 blkptr_t *bp = &lr->lr_blkptr;
496 zbookmark_t zb;
497
498 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
499 return (0);
500
501 /*
502 * birth can be < claim_txg if this record's txg is
503 * already txg sync'ed (but this log block contains
504 * other records that are not synced)
505 */
506 if (claim_txg == 0 || bp->blk_birth < claim_txg)
507 return (0);
508
509 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
510 lr->lr_foid, ZB_ZIL_LEVEL,
511 lr->lr_offset / BP_GET_LSIZE(bp));
512
513 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
514 }
515 return (0);
516 }
517
518 static void
519 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
520 {
521 uint64_t claim_txg = zh->zh_claim_txg;
522 zil_scan_arg_t zsa = { dp, zh };
523 zilog_t *zilog;
524
525 /*
526 * We only want to visit blocks that have been claimed but not yet
527 * replayed (or, in read-only mode, blocks that *would* be claimed).
528 */
529 if (claim_txg == 0 && spa_writeable(dp->dp_spa))
530 return;
531
532 zilog = zil_alloc(dp->dp_meta_objset, zh);
533
534 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
535 claim_txg);
536
537 zil_free(zilog);
538 }
539
540 /* ARGSUSED */
541 static void
542 dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
543 uint64_t objset, uint64_t object, uint64_t blkid)
544 {
545 zbookmark_t czb;
546 uint32_t flags = ARC_NOWAIT | ARC_PREFETCH;
547
548 if (zfs_no_scrub_prefetch)
549 return;
550
551 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_min_txg ||
552 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE))
553 return;
554
555 SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
556
557 /*
558 * XXX need to make sure all of these arc_read() prefetches are
559 * done before setting xlateall (similar to dsl_read())
560 */
561 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
562 buf, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
563 ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
564 }
565
566 static boolean_t
567 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
568 const zbookmark_t *zb)
569 {
570 /*
571 * We never skip over user/group accounting objects (obj<0)
572 */
573 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
574 (int64_t)zb->zb_object >= 0) {
575 /*
576 * If we already visited this bp & everything below (in
577 * a prior txg sync), don't bother doing it again.
578 */
579 if (zbookmark_is_before(dnp, zb, &scn->scn_phys.scn_bookmark))
580 return (B_TRUE);
581
582 /*
583 * If we found the block we're trying to resume from, or
584 * we went past it to a different object, zero it out to
585 * indicate that it's OK to start checking for pausing
586 * again.
587 */
588 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
589 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
590 dprintf("resuming at %llx/%llx/%llx/%llx\n",
591 (longlong_t)zb->zb_objset,
592 (longlong_t)zb->zb_object,
593 (longlong_t)zb->zb_level,
594 (longlong_t)zb->zb_blkid);
595 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
596 }
597 }
598 return (B_FALSE);
599 }
600
601 /*
602 * Return nonzero on i/o error.
603 * Return new buf to write out in *bufp.
604 */
605 static int
606 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
607 dnode_phys_t *dnp, const blkptr_t *bp,
608 const zbookmark_t *zb, dmu_tx_t *tx, arc_buf_t **bufp)
609 {
610 dsl_pool_t *dp = scn->scn_dp;
611 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
612 int err;
613
614 if (BP_GET_LEVEL(bp) > 0) {
615 uint32_t flags = ARC_WAIT;
616 int i;
617 blkptr_t *cbp;
618 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
619
620 err = arc_read_nolock(NULL, dp->dp_spa, bp,
621 arc_getbuf_func, bufp,
622 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
623 if (err) {
624 scn->scn_phys.scn_errors++;
625 return (err);
626 }
627 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
628 dsl_scan_prefetch(scn, *bufp, cbp, zb->zb_objset,
629 zb->zb_object, zb->zb_blkid * epb + i);
630 }
631 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
632 zbookmark_t czb;
633
634 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
635 zb->zb_level - 1,
636 zb->zb_blkid * epb + i);
637 dsl_scan_visitbp(cbp, &czb, dnp,
638 *bufp, ds, scn, ostype, tx);
639 }
640 } else if (BP_GET_TYPE(bp) == DMU_OT_USERGROUP_USED) {
641 uint32_t flags = ARC_WAIT;
642
643 err = arc_read_nolock(NULL, dp->dp_spa, bp,
644 arc_getbuf_func, bufp,
645 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
646 if (err) {
647 scn->scn_phys.scn_errors++;
648 return (err);
649 }
650 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
651 uint32_t flags = ARC_WAIT;
652 dnode_phys_t *cdnp;
653 int i, j;
654 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
655
656 err = arc_read_nolock(NULL, dp->dp_spa, bp,
657 arc_getbuf_func, bufp,
658 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
659 if (err) {
660 scn->scn_phys.scn_errors++;
661 return (err);
662 }
663 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
664 for (j = 0; j < cdnp->dn_nblkptr; j++) {
665 blkptr_t *cbp = &cdnp->dn_blkptr[j];
666 dsl_scan_prefetch(scn, *bufp, cbp,
667 zb->zb_objset, zb->zb_blkid * epb + i, j);
668 }
669 }
670 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
671 dsl_scan_visitdnode(scn, ds, ostype,
672 cdnp, *bufp, zb->zb_blkid * epb + i, tx);
673 }
674
675 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
676 uint32_t flags = ARC_WAIT;
677 objset_phys_t *osp;
678
679 err = arc_read_nolock(NULL, dp->dp_spa, bp,
680 arc_getbuf_func, bufp,
681 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
682 if (err) {
683 scn->scn_phys.scn_errors++;
684 return (err);
685 }
686
687 osp = (*bufp)->b_data;
688
689 dsl_scan_visitdnode(scn, ds, osp->os_type,
690 &osp->os_meta_dnode, *bufp, DMU_META_DNODE_OBJECT, tx);
691
692 if (OBJSET_BUF_HAS_USERUSED(*bufp)) {
693 /*
694 * We also always visit user/group accounting
695 * objects, and never skip them, even if we are
696 * pausing. This is necessary so that the space
697 * deltas from this txg get integrated.
698 */
699 dsl_scan_visitdnode(scn, ds, osp->os_type,
700 &osp->os_groupused_dnode, *bufp,
701 DMU_GROUPUSED_OBJECT, tx);
702 dsl_scan_visitdnode(scn, ds, osp->os_type,
703 &osp->os_userused_dnode, *bufp,
704 DMU_USERUSED_OBJECT, tx);
705 }
706 }
707
708 return (0);
709 }
710
711 static void
712 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
713 dmu_objset_type_t ostype, dnode_phys_t *dnp, arc_buf_t *buf,
714 uint64_t object, dmu_tx_t *tx)
715 {
716 int j;
717
718 for (j = 0; j < dnp->dn_nblkptr; j++) {
719 zbookmark_t czb;
720
721 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
722 dnp->dn_nlevels - 1, j);
723 dsl_scan_visitbp(&dnp->dn_blkptr[j],
724 &czb, dnp, buf, ds, scn, ostype, tx);
725 }
726
727 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
728 zbookmark_t czb;
729 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
730 0, DMU_SPILL_BLKID);
731 dsl_scan_visitbp(&dnp->dn_spill,
732 &czb, dnp, buf, ds, scn, ostype, tx);
733 }
734 }
735
736 /*
737 * The arguments are in this order because mdb can only print the
738 * first 5; we want them to be useful.
739 */
740 static void
741 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_t *zb,
742 dnode_phys_t *dnp, arc_buf_t *pbuf,
743 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
744 dmu_tx_t *tx)
745 {
746 dsl_pool_t *dp = scn->scn_dp;
747 arc_buf_t *buf = NULL;
748 blkptr_t bp_toread = *bp;
749
750 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
751
752 if (dsl_scan_check_pause(scn, zb))
753 return;
754
755 if (dsl_scan_check_resume(scn, dnp, zb))
756 return;
757
758 if (bp->blk_birth == 0)
759 return;
760
761 scn->scn_visited_this_txg++;
762
763 dprintf_bp(bp,
764 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx buf=%p bp=%p",
765 ds, ds ? ds->ds_object : 0,
766 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
767 pbuf, bp);
768
769 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
770 return;
771
772 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx,
773 &buf) != 0)
774 return;
775
776 /*
777 * If dsl_scan_ddt() has aready visited this block, it will have
778 * already done any translations or scrubbing, so don't call the
779 * callback again.
780 */
781 if (ddt_class_contains(dp->dp_spa,
782 scn->scn_phys.scn_ddt_class_max, bp)) {
783 ASSERT(buf == NULL);
784 return;
785 }
786
787 /*
788 * If this block is from the future (after cur_max_txg), then we
789 * are doing this on behalf of a deleted snapshot, and we will
790 * revisit the future block on the next pass of this dataset.
791 * Don't scan it now unless we need to because something
792 * under it was modified.
793 */
794 if (bp->blk_birth <= scn->scn_phys.scn_cur_max_txg) {
795 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
796 }
797 if (buf)
798 (void) arc_buf_remove_ref(buf, &buf);
799 }
800
801 static void
802 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
803 dmu_tx_t *tx)
804 {
805 zbookmark_t zb;
806
807 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
808 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
809 dsl_scan_visitbp(bp, &zb, NULL, NULL,
810 ds, scn, DMU_OST_NONE, tx);
811
812 dprintf_ds(ds, "finished scan%s", "");
813 }
814
815 void
816 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
817 {
818 dsl_pool_t *dp = ds->ds_dir->dd_pool;
819 dsl_scan_t *scn = dp->dp_scan;
820 uint64_t mintxg;
821
822 if (scn->scn_phys.scn_state != DSS_SCANNING)
823 return;
824
825 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
826 if (dsl_dataset_is_snapshot(ds)) {
827 /* Note, scn_cur_{min,max}_txg stays the same. */
828 scn->scn_phys.scn_bookmark.zb_objset =
829 ds->ds_phys->ds_next_snap_obj;
830 zfs_dbgmsg("destroying ds %llu; currently traversing; "
831 "reset zb_objset to %llu",
832 (u_longlong_t)ds->ds_object,
833 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
834 scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
835 } else {
836 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
837 ZB_DESTROYED_OBJSET, 0, 0, 0);
838 zfs_dbgmsg("destroying ds %llu; currently traversing; "
839 "reset bookmark to -1,0,0,0",
840 (u_longlong_t)ds->ds_object);
841 }
842 } else if (zap_lookup_int_key(dp->dp_meta_objset,
843 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
844 ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
845 VERIFY0(zap_remove_int(dp->dp_meta_objset,
846 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
847 if (dsl_dataset_is_snapshot(ds)) {
848 /*
849 * We keep the same mintxg; it could be >
850 * ds_creation_txg if the previous snapshot was
851 * deleted too.
852 */
853 VERIFY(zap_add_int_key(dp->dp_meta_objset,
854 scn->scn_phys.scn_queue_obj,
855 ds->ds_phys->ds_next_snap_obj, mintxg, tx) == 0);
856 zfs_dbgmsg("destroying ds %llu; in queue; "
857 "replacing with %llu",
858 (u_longlong_t)ds->ds_object,
859 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
860 } else {
861 zfs_dbgmsg("destroying ds %llu; in queue; removing",
862 (u_longlong_t)ds->ds_object);
863 }
864 } else {
865 zfs_dbgmsg("destroying ds %llu; ignoring",
866 (u_longlong_t)ds->ds_object);
867 }
868
869 /*
870 * dsl_scan_sync() should be called after this, and should sync
871 * out our changed state, but just to be safe, do it here.
872 */
873 dsl_scan_sync_state(scn, tx);
874 }
875
876 void
877 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
878 {
879 dsl_pool_t *dp = ds->ds_dir->dd_pool;
880 dsl_scan_t *scn = dp->dp_scan;
881 uint64_t mintxg;
882
883 if (scn->scn_phys.scn_state != DSS_SCANNING)
884 return;
885
886 ASSERT(ds->ds_phys->ds_prev_snap_obj != 0);
887
888 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
889 scn->scn_phys.scn_bookmark.zb_objset =
890 ds->ds_phys->ds_prev_snap_obj;
891 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
892 "reset zb_objset to %llu",
893 (u_longlong_t)ds->ds_object,
894 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
895 } else if (zap_lookup_int_key(dp->dp_meta_objset,
896 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
897 VERIFY0(zap_remove_int(dp->dp_meta_objset,
898 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
899 VERIFY(zap_add_int_key(dp->dp_meta_objset,
900 scn->scn_phys.scn_queue_obj,
901 ds->ds_phys->ds_prev_snap_obj, mintxg, tx) == 0);
902 zfs_dbgmsg("snapshotting ds %llu; in queue; "
903 "replacing with %llu",
904 (u_longlong_t)ds->ds_object,
905 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
906 }
907 dsl_scan_sync_state(scn, tx);
908 }
909
910 void
911 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
912 {
913 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
914 dsl_scan_t *scn = dp->dp_scan;
915 uint64_t mintxg;
916
917 if (scn->scn_phys.scn_state != DSS_SCANNING)
918 return;
919
920 if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
921 scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
922 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
923 "reset zb_objset to %llu",
924 (u_longlong_t)ds1->ds_object,
925 (u_longlong_t)ds2->ds_object);
926 } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
927 scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
928 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
929 "reset zb_objset to %llu",
930 (u_longlong_t)ds2->ds_object,
931 (u_longlong_t)ds1->ds_object);
932 }
933
934 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
935 ds1->ds_object, &mintxg) == 0) {
936 int err;
937
938 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
939 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
940 VERIFY0(zap_remove_int(dp->dp_meta_objset,
941 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
942 err = zap_add_int_key(dp->dp_meta_objset,
943 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
944 VERIFY(err == 0 || err == EEXIST);
945 if (err == EEXIST) {
946 /* Both were there to begin with */
947 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
948 scn->scn_phys.scn_queue_obj,
949 ds1->ds_object, mintxg, tx));
950 }
951 zfs_dbgmsg("clone_swap ds %llu; in queue; "
952 "replacing with %llu",
953 (u_longlong_t)ds1->ds_object,
954 (u_longlong_t)ds2->ds_object);
955 } else if (zap_lookup_int_key(dp->dp_meta_objset,
956 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
957 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
958 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
959 VERIFY0(zap_remove_int(dp->dp_meta_objset,
960 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
961 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
962 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
963 zfs_dbgmsg("clone_swap ds %llu; in queue; "
964 "replacing with %llu",
965 (u_longlong_t)ds2->ds_object,
966 (u_longlong_t)ds1->ds_object);
967 }
968
969 dsl_scan_sync_state(scn, tx);
970 }
971
972 struct enqueue_clones_arg {
973 dmu_tx_t *tx;
974 uint64_t originobj;
975 };
976
977 /* ARGSUSED */
978 static int
979 enqueue_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
980 {
981 struct enqueue_clones_arg *eca = arg;
982 dsl_dataset_t *ds;
983 int err;
984 dsl_pool_t *dp = spa->spa_dsl_pool;
985 dsl_scan_t *scn = dp->dp_scan;
986
987 err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
988 if (err)
989 return (err);
990
991 if (ds->ds_dir->dd_phys->dd_origin_obj == eca->originobj) {
992 while (ds->ds_phys->ds_prev_snap_obj != eca->originobj) {
993 dsl_dataset_t *prev;
994 err = dsl_dataset_hold_obj(dp,
995 ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
996
997 dsl_dataset_rele(ds, FTAG);
998 if (err)
999 return (err);
1000 ds = prev;
1001 }
1002 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1003 scn->scn_phys.scn_queue_obj, ds->ds_object,
1004 ds->ds_phys->ds_prev_snap_txg, eca->tx) == 0);
1005 }
1006 dsl_dataset_rele(ds, FTAG);
1007 return (0);
1008 }
1009
1010 static void
1011 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
1012 {
1013 dsl_pool_t *dp = scn->scn_dp;
1014 dsl_dataset_t *ds;
1015 objset_t *os;
1016
1017 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1018
1019 if (dmu_objset_from_ds(ds, &os))
1020 goto out;
1021
1022 /*
1023 * Only the ZIL in the head (non-snapshot) is valid. Even though
1024 * snapshots can have ZIL block pointers (which may be the same
1025 * BP as in the head), they must be ignored. So we traverse the
1026 * ZIL here, rather than in scan_recurse(), because the regular
1027 * snapshot block-sharing rules don't apply to it.
1028 */
1029 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !dsl_dataset_is_snapshot(ds))
1030 dsl_scan_zil(dp, &os->os_zil_header);
1031
1032 /*
1033 * Iterate over the bps in this ds.
1034 */
1035 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1036 dsl_scan_visit_rootbp(scn, ds, &ds->ds_phys->ds_bp, tx);
1037
1038 char *dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
1039 dsl_dataset_name(ds, dsname);
1040 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1041 "pausing=%u",
1042 (longlong_t)dsobj, dsname,
1043 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1044 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1045 (int)scn->scn_pausing);
1046 kmem_free(dsname, ZFS_MAXNAMELEN);
1047
1048 if (scn->scn_pausing)
1049 goto out;
1050
1051 /*
1052 * We've finished this pass over this dataset.
1053 */
1054
1055 /*
1056 * If we did not completely visit this dataset, do another pass.
1057 */
1058 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1059 zfs_dbgmsg("incomplete pass; visiting again");
1060 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1061 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1062 scn->scn_phys.scn_queue_obj, ds->ds_object,
1063 scn->scn_phys.scn_cur_max_txg, tx) == 0);
1064 goto out;
1065 }
1066
1067 /*
1068 * Add descendent datasets to work queue.
1069 */
1070 if (ds->ds_phys->ds_next_snap_obj != 0) {
1071 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1072 scn->scn_phys.scn_queue_obj, ds->ds_phys->ds_next_snap_obj,
1073 ds->ds_phys->ds_creation_txg, tx) == 0);
1074 }
1075 if (ds->ds_phys->ds_num_children > 1) {
1076 boolean_t usenext = B_FALSE;
1077 if (ds->ds_phys->ds_next_clones_obj != 0) {
1078 uint64_t count;
1079 /*
1080 * A bug in a previous version of the code could
1081 * cause upgrade_clones_cb() to not set
1082 * ds_next_snap_obj when it should, leading to a
1083 * missing entry. Therefore we can only use the
1084 * next_clones_obj when its count is correct.
1085 */
1086 int err = zap_count(dp->dp_meta_objset,
1087 ds->ds_phys->ds_next_clones_obj, &count);
1088 if (err == 0 &&
1089 count == ds->ds_phys->ds_num_children - 1)
1090 usenext = B_TRUE;
1091 }
1092
1093 if (usenext) {
1094 VERIFY(zap_join_key(dp->dp_meta_objset,
1095 ds->ds_phys->ds_next_clones_obj,
1096 scn->scn_phys.scn_queue_obj,
1097 ds->ds_phys->ds_creation_txg, tx) == 0);
1098 } else {
1099 struct enqueue_clones_arg eca;
1100 eca.tx = tx;
1101 eca.originobj = ds->ds_object;
1102
1103 (void) dmu_objset_find_spa(ds->ds_dir->dd_pool->dp_spa,
1104 NULL, enqueue_clones_cb, &eca, DS_FIND_CHILDREN);
1105 }
1106 }
1107
1108 out:
1109 dsl_dataset_rele(ds, FTAG);
1110 }
1111
1112 /* ARGSUSED */
1113 static int
1114 enqueue_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
1115 {
1116 dmu_tx_t *tx = arg;
1117 dsl_dataset_t *ds;
1118 int err;
1119 dsl_pool_t *dp = spa->spa_dsl_pool;
1120 dsl_scan_t *scn = dp->dp_scan;
1121
1122 err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
1123 if (err)
1124 return (err);
1125
1126 while (ds->ds_phys->ds_prev_snap_obj != 0) {
1127 dsl_dataset_t *prev;
1128 err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
1129 FTAG, &prev);
1130 if (err) {
1131 dsl_dataset_rele(ds, FTAG);
1132 return (err);
1133 }
1134
1135 /*
1136 * If this is a clone, we don't need to worry about it for now.
1137 */
1138 if (prev->ds_phys->ds_next_snap_obj != ds->ds_object) {
1139 dsl_dataset_rele(ds, FTAG);
1140 dsl_dataset_rele(prev, FTAG);
1141 return (0);
1142 }
1143 dsl_dataset_rele(ds, FTAG);
1144 ds = prev;
1145 }
1146
1147 VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1148 ds->ds_object, ds->ds_phys->ds_prev_snap_txg, tx) == 0);
1149 dsl_dataset_rele(ds, FTAG);
1150 return (0);
1151 }
1152
1153 /*
1154 * Scrub/dedup interaction.
1155 *
1156 * If there are N references to a deduped block, we don't want to scrub it
1157 * N times -- ideally, we should scrub it exactly once.
1158 *
1159 * We leverage the fact that the dde's replication class (enum ddt_class)
1160 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1161 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1162 *
1163 * To prevent excess scrubbing, the scrub begins by walking the DDT
1164 * to find all blocks with refcnt > 1, and scrubs each of these once.
1165 * Since there are two replication classes which contain blocks with
1166 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1167 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1168 *
1169 * There would be nothing more to say if a block's refcnt couldn't change
1170 * during a scrub, but of course it can so we must account for changes
1171 * in a block's replication class.
1172 *
1173 * Here's an example of what can occur:
1174 *
1175 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
1176 * when visited during the top-down scrub phase, it will be scrubbed twice.
1177 * This negates our scrub optimization, but is otherwise harmless.
1178 *
1179 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1180 * on each visit during the top-down scrub phase, it will never be scrubbed.
1181 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1182 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1183 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1184 * while a scrub is in progress, it scrubs the block right then.
1185 */
1186 static void
1187 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1188 {
1189 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1190 ddt_entry_t dde = { 0 };
1191 int error;
1192 uint64_t n = 0;
1193
1194 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1195 ddt_t *ddt;
1196
1197 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1198 break;
1199 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1200 (longlong_t)ddb->ddb_class,
1201 (longlong_t)ddb->ddb_type,
1202 (longlong_t)ddb->ddb_checksum,
1203 (longlong_t)ddb->ddb_cursor);
1204
1205 /* There should be no pending changes to the dedup table */
1206 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1207 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
1208
1209 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1210 n++;
1211
1212 if (dsl_scan_check_pause(scn, NULL))
1213 break;
1214 }
1215
1216 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; pausing=%u",
1217 (longlong_t)n, (int)scn->scn_phys.scn_ddt_class_max,
1218 (int)scn->scn_pausing);
1219
1220 ASSERT(error == 0 || error == ENOENT);
1221 ASSERT(error != ENOENT ||
1222 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1223 }
1224
1225 /* ARGSUSED */
1226 void
1227 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1228 ddt_entry_t *dde, dmu_tx_t *tx)
1229 {
1230 const ddt_key_t *ddk = &dde->dde_key;
1231 ddt_phys_t *ddp = dde->dde_phys;
1232 blkptr_t bp;
1233 zbookmark_t zb = { 0 };
1234
1235 if (scn->scn_phys.scn_state != DSS_SCANNING)
1236 return;
1237
1238 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1239 if (ddp->ddp_phys_birth == 0 ||
1240 ddp->ddp_phys_birth > scn->scn_phys.scn_cur_max_txg)
1241 continue;
1242 ddt_bp_create(checksum, ddk, ddp, &bp);
1243
1244 scn->scn_visited_this_txg++;
1245 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1246 }
1247 }
1248
1249 static void
1250 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1251 {
1252 dsl_pool_t *dp = scn->scn_dp;
1253 zap_cursor_t zc;
1254 zap_attribute_t za;
1255
1256 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1257 scn->scn_phys.scn_ddt_class_max) {
1258 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1259 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1260 dsl_scan_ddt(scn, tx);
1261 if (scn->scn_pausing)
1262 return;
1263 }
1264
1265 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1266 /* First do the MOS & ORIGIN */
1267
1268 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1269 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1270 dsl_scan_visit_rootbp(scn, NULL,
1271 &dp->dp_meta_rootbp, tx);
1272 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1273 if (scn->scn_pausing)
1274 return;
1275
1276 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1277 VERIFY(0 == dmu_objset_find_spa(dp->dp_spa,
1278 NULL, enqueue_cb, tx, DS_FIND_CHILDREN));
1279 } else {
1280 dsl_scan_visitds(scn,
1281 dp->dp_origin_snap->ds_object, tx);
1282 }
1283 ASSERT(!scn->scn_pausing);
1284 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
1285 ZB_DESTROYED_OBJSET) {
1286 /*
1287 * If we were paused, continue from here. Note if the
1288 * ds we were paused on was deleted, the zb_objset may
1289 * be -1, so we will skip this and find a new objset
1290 * below.
1291 */
1292 dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
1293 if (scn->scn_pausing)
1294 return;
1295 }
1296
1297 /*
1298 * In case we were paused right at the end of the ds, zero the
1299 * bookmark so we don't think that we're still trying to resume.
1300 */
1301 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_t));
1302
1303 /* keep pulling things out of the zap-object-as-queue */
1304 while (zap_cursor_init(&zc, dp->dp_meta_objset,
1305 scn->scn_phys.scn_queue_obj),
1306 zap_cursor_retrieve(&zc, &za) == 0) {
1307 dsl_dataset_t *ds;
1308 uint64_t dsobj;
1309
1310 dsobj = strtonum(za.za_name, NULL);
1311 VERIFY0(zap_remove_int(dp->dp_meta_objset,
1312 scn->scn_phys.scn_queue_obj, dsobj, tx));
1313
1314 /* Set up min/max txg */
1315 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1316 if (za.za_first_integer != 0) {
1317 scn->scn_phys.scn_cur_min_txg =
1318 MAX(scn->scn_phys.scn_min_txg,
1319 za.za_first_integer);
1320 } else {
1321 scn->scn_phys.scn_cur_min_txg =
1322 MAX(scn->scn_phys.scn_min_txg,
1323 ds->ds_phys->ds_prev_snap_txg);
1324 }
1325 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
1326 dsl_dataset_rele(ds, FTAG);
1327
1328 dsl_scan_visitds(scn, dsobj, tx);
1329 zap_cursor_fini(&zc);
1330 if (scn->scn_pausing)
1331 return;
1332 }
1333 zap_cursor_fini(&zc);
1334 }
1335
1336 static boolean_t
1337 dsl_scan_free_should_pause(dsl_scan_t *scn)
1338 {
1339 uint64_t elapsed_nanosecs;
1340
1341 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
1342 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
1343 (elapsed_nanosecs / MICROSEC > zfs_free_min_time_ms &&
1344 txg_sync_waiting(scn->scn_dp)) ||
1345 spa_shutting_down(scn->scn_dp->dp_spa));
1346 }
1347
1348 static int
1349 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1350 {
1351 dsl_scan_t *scn = arg;
1352
1353 if (!scn->scn_is_bptree ||
1354 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
1355 if (dsl_scan_free_should_pause(scn))
1356 return (ERESTART);
1357 }
1358
1359 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
1360 dmu_tx_get_txg(tx), bp, 0));
1361 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
1362 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
1363 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
1364 scn->scn_visited_this_txg++;
1365 return (0);
1366 }
1367
1368 boolean_t
1369 dsl_scan_active(dsl_scan_t *scn)
1370 {
1371 spa_t *spa = scn->scn_dp->dp_spa;
1372 uint64_t used = 0, comp, uncomp;
1373
1374 if (spa->spa_load_state != SPA_LOAD_NONE)
1375 return (B_FALSE);
1376 if (spa_shutting_down(spa))
1377 return (B_FALSE);
1378
1379 if (scn->scn_phys.scn_state == DSS_SCANNING)
1380 return (B_TRUE);
1381
1382 if (spa_feature_is_active(spa,
1383 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
1384 return (B_TRUE);
1385 }
1386 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1387 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
1388 &used, &comp, &uncomp);
1389 }
1390 return (used != 0);
1391 }
1392
1393 void
1394 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
1395 {
1396 dsl_scan_t *scn = dp->dp_scan;
1397 spa_t *spa = dp->dp_spa;
1398 int err;
1399
1400 /*
1401 * Check for scn_restart_txg before checking spa_load_state, so
1402 * that we can restart an old-style scan while the pool is being
1403 * imported (see dsl_scan_init).
1404 */
1405 if (scn->scn_restart_txg != 0 &&
1406 scn->scn_restart_txg <= tx->tx_txg) {
1407 pool_scan_func_t func = POOL_SCAN_SCRUB;
1408 dsl_scan_done(scn, B_FALSE, tx);
1409 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
1410 func = POOL_SCAN_RESILVER;
1411 zfs_dbgmsg("restarting scan func=%u txg=%llu",
1412 func, tx->tx_txg);
1413 dsl_scan_setup_sync(scn, &func, tx);
1414 }
1415
1416 if (!dsl_scan_active(scn) ||
1417 spa_sync_pass(dp->dp_spa) > 1)
1418 return;
1419
1420 scn->scn_visited_this_txg = 0;
1421 scn->scn_pausing = B_FALSE;
1422 scn->scn_sync_start_time = gethrtime();
1423 spa->spa_scrub_active = B_TRUE;
1424
1425 /*
1426 * First process the free list. If we pause the free, don't do
1427 * any scanning. This ensures that there is no free list when
1428 * we are scanning, so the scan code doesn't have to worry about
1429 * traversing it.
1430 */
1431 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1432 scn->scn_is_bptree = B_FALSE;
1433 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1434 NULL, ZIO_FLAG_MUSTSUCCEED);
1435 err = bpobj_iterate(&dp->dp_free_bpobj,
1436 dsl_scan_free_block_cb, scn, tx);
1437 VERIFY0(zio_wait(scn->scn_zio_root));
1438
1439 if (err == 0 && spa_feature_is_active(spa,
1440 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
1441 scn->scn_is_bptree = B_TRUE;
1442 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1443 NULL, ZIO_FLAG_MUSTSUCCEED);
1444 err = bptree_iterate(dp->dp_meta_objset,
1445 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb,
1446 scn, tx);
1447 VERIFY0(zio_wait(scn->scn_zio_root));
1448 if (err != 0)
1449 return;
1450
1451 /* disable async destroy feature */
1452 spa_feature_decr(spa,
1453 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY], tx);
1454 ASSERT(!spa_feature_is_active(spa,
1455 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY]));
1456 VERIFY0(zap_remove(dp->dp_meta_objset,
1457 DMU_POOL_DIRECTORY_OBJECT,
1458 DMU_POOL_BPTREE_OBJ, tx));
1459 VERIFY0(bptree_free(dp->dp_meta_objset,
1460 dp->dp_bptree_obj, tx));
1461 dp->dp_bptree_obj = 0;
1462 }
1463 if (scn->scn_visited_this_txg) {
1464 zfs_dbgmsg("freed %llu blocks in %llums from "
1465 "free_bpobj/bptree txg %llu",
1466 (longlong_t)scn->scn_visited_this_txg,
1467 (longlong_t)
1468 (gethrtime() - scn->scn_sync_start_time) / MICROSEC,
1469 (longlong_t)tx->tx_txg);
1470 scn->scn_visited_this_txg = 0;
1471 /*
1472 * Re-sync the ddt so that we can further modify
1473 * it when doing bprewrite.
1474 */
1475 ddt_sync(spa, tx->tx_txg);
1476 }
1477 if (err == ERESTART)
1478 return;
1479 }
1480
1481 if (scn->scn_phys.scn_state != DSS_SCANNING)
1482 return;
1483
1484 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1485 scn->scn_phys.scn_ddt_class_max) {
1486 zfs_dbgmsg("doing scan sync txg %llu; "
1487 "ddt bm=%llu/%llu/%llu/%llx",
1488 (longlong_t)tx->tx_txg,
1489 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1490 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1491 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1492 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1493 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
1494 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
1495 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
1496 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
1497 } else {
1498 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
1499 (longlong_t)tx->tx_txg,
1500 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
1501 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
1502 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
1503 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
1504 }
1505
1506 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1507 NULL, ZIO_FLAG_CANFAIL);
1508 dsl_scan_visit(scn, tx);
1509 (void) zio_wait(scn->scn_zio_root);
1510 scn->scn_zio_root = NULL;
1511
1512 zfs_dbgmsg("visited %llu blocks in %llums",
1513 (longlong_t)scn->scn_visited_this_txg,
1514 (longlong_t)(gethrtime() - scn->scn_sync_start_time) / MICROSEC);
1515
1516 if (!scn->scn_pausing) {
1517 /* finished with scan. */
1518 zfs_dbgmsg("finished scan txg %llu", (longlong_t)tx->tx_txg);
1519 dsl_scan_done(scn, B_TRUE, tx);
1520 }
1521
1522 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
1523 mutex_enter(&spa->spa_scrub_lock);
1524 while (spa->spa_scrub_inflight > 0) {
1525 cv_wait(&spa->spa_scrub_io_cv,
1526 &spa->spa_scrub_lock);
1527 }
1528 mutex_exit(&spa->spa_scrub_lock);
1529 }
1530
1531 dsl_scan_sync_state(scn, tx);
1532 }
1533
1534 /*
1535 * This will start a new scan, or restart an existing one.
1536 */
1537 void
1538 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
1539 {
1540 if (txg == 0) {
1541 dmu_tx_t *tx;
1542 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1543 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1544
1545 txg = dmu_tx_get_txg(tx);
1546 dp->dp_scan->scn_restart_txg = txg;
1547 dmu_tx_commit(tx);
1548 } else {
1549 dp->dp_scan->scn_restart_txg = txg;
1550 }
1551 zfs_dbgmsg("restarting resilver txg=%llu", txg);
1552 }
1553
1554 boolean_t
1555 dsl_scan_resilvering(dsl_pool_t *dp)
1556 {
1557 return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
1558 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
1559 }
1560
1561 /*
1562 * scrub consumers
1563 */
1564
1565 static void
1566 count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
1567 {
1568 int i;
1569
1570 /*
1571 * If we resume after a reboot, zab will be NULL; don't record
1572 * incomplete stats in that case.
1573 */
1574 if (zab == NULL)
1575 return;
1576
1577 for (i = 0; i < 4; i++) {
1578 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
1579 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
1580 if (t & DMU_OT_NEWTYPE)
1581 t = DMU_OT_OTHER;
1582 zfs_blkstat_t *zb = &zab->zab_type[l][t];
1583 int equal;
1584
1585 zb->zb_count++;
1586 zb->zb_asize += BP_GET_ASIZE(bp);
1587 zb->zb_lsize += BP_GET_LSIZE(bp);
1588 zb->zb_psize += BP_GET_PSIZE(bp);
1589 zb->zb_gangs += BP_COUNT_GANG(bp);
1590
1591 switch (BP_GET_NDVAS(bp)) {
1592 case 2:
1593 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1594 DVA_GET_VDEV(&bp->blk_dva[1]))
1595 zb->zb_ditto_2_of_2_samevdev++;
1596 break;
1597 case 3:
1598 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1599 DVA_GET_VDEV(&bp->blk_dva[1])) +
1600 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1601 DVA_GET_VDEV(&bp->blk_dva[2])) +
1602 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
1603 DVA_GET_VDEV(&bp->blk_dva[2]));
1604 if (equal == 1)
1605 zb->zb_ditto_2_of_3_samevdev++;
1606 else if (equal == 3)
1607 zb->zb_ditto_3_of_3_samevdev++;
1608 break;
1609 }
1610 }
1611 }
1612
1613 static void
1614 dsl_scan_scrub_done(zio_t *zio)
1615 {
1616 spa_t *spa = zio->io_spa;
1617
1618 zio_data_buf_free(zio->io_data, zio->io_size);
1619
1620 mutex_enter(&spa->spa_scrub_lock);
1621 spa->spa_scrub_inflight--;
1622 cv_broadcast(&spa->spa_scrub_io_cv);
1623
1624 if (zio->io_error && (zio->io_error != ECKSUM ||
1625 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
1626 spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
1627 }
1628 mutex_exit(&spa->spa_scrub_lock);
1629 }
1630
1631 static int
1632 dsl_scan_scrub_cb(dsl_pool_t *dp,
1633 const blkptr_t *bp, const zbookmark_t *zb)
1634 {
1635 dsl_scan_t *scn = dp->dp_scan;
1636 size_t size = BP_GET_PSIZE(bp);
1637 spa_t *spa = dp->dp_spa;
1638 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
1639 boolean_t needs_io;
1640 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
1641 int zio_priority;
1642 int scan_delay = 0;
1643
1644 if (phys_birth <= scn->scn_phys.scn_min_txg ||
1645 phys_birth >= scn->scn_phys.scn_max_txg)
1646 return (0);
1647
1648 count_block(dp->dp_blkstats, bp);
1649
1650 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
1651 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
1652 zio_flags |= ZIO_FLAG_SCRUB;
1653 zio_priority = ZIO_PRIORITY_SCRUB;
1654 needs_io = B_TRUE;
1655 scan_delay = zfs_scrub_delay;
1656 } else if (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) {
1657 zio_flags |= ZIO_FLAG_RESILVER;
1658 zio_priority = ZIO_PRIORITY_RESILVER;
1659 needs_io = B_FALSE;
1660 scan_delay = zfs_resilver_delay;
1661 }
1662
1663 /* If it's an intent log block, failure is expected. */
1664 if (zb->zb_level == ZB_ZIL_LEVEL)
1665 zio_flags |= ZIO_FLAG_SPECULATIVE;
1666
1667 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
1668 vdev_t *vd = vdev_lookup_top(spa,
1669 DVA_GET_VDEV(&bp->blk_dva[d]));
1670
1671 /*
1672 * Keep track of how much data we've examined so that
1673 * zpool(1M) status can make useful progress reports.
1674 */
1675 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
1676 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
1677
1678 /* if it's a resilver, this may not be in the target range */
1679 if (!needs_io) {
1680 if (DVA_GET_GANG(&bp->blk_dva[d])) {
1681 /*
1682 * Gang members may be spread across multiple
1683 * vdevs, so the best estimate we have is the
1684 * scrub range, which has already been checked.
1685 * XXX -- it would be better to change our
1686 * allocation policy to ensure that all
1687 * gang members reside on the same vdev.
1688 */
1689 needs_io = B_TRUE;
1690 } else {
1691 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
1692 phys_birth, 1);
1693 }
1694 }
1695 }
1696
1697 if (needs_io && !zfs_no_scrub_io) {
1698 vdev_t *rvd = spa->spa_root_vdev;
1699 uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
1700 void *data = zio_data_buf_alloc(size);
1701
1702 mutex_enter(&spa->spa_scrub_lock);
1703 while (spa->spa_scrub_inflight >= maxinflight)
1704 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1705 spa->spa_scrub_inflight++;
1706 mutex_exit(&spa->spa_scrub_lock);
1707
1708 /*
1709 * If we're seeing recent (zfs_scan_idle) "important" I/Os
1710 * then throttle our workload to limit the impact of a scan.
1711 */
1712 if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
1713 delay(scan_delay);
1714
1715 zio_nowait(zio_read(NULL, spa, bp, data, size,
1716 dsl_scan_scrub_done, NULL, zio_priority,
1717 zio_flags, zb));
1718 }
1719
1720 /* do not relocate this block */
1721 return (0);
1722 }
1723
1724 int
1725 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
1726 {
1727 spa_t *spa = dp->dp_spa;
1728
1729 /*
1730 * Purge all vdev caches and probe all devices. We do this here
1731 * rather than in sync context because this requires a writer lock
1732 * on the spa_config lock, which we can't do from sync context. The
1733 * spa_scrub_reopen flag indicates that vdev_open() should not
1734 * attempt to start another scrub.
1735 */
1736 spa_vdev_state_enter(spa, SCL_NONE);
1737 spa->spa_scrub_reopen = B_TRUE;
1738 vdev_reopen(spa->spa_root_vdev);
1739 spa->spa_scrub_reopen = B_FALSE;
1740 (void) spa_vdev_state_exit(spa, NULL, 0);
1741
1742 return (dsl_sync_task_do(dp, dsl_scan_setup_check,
1743 dsl_scan_setup_sync, dp->dp_scan, &func, 0));
1744 }