1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Delphix. All rights reserved.
24 */
25
26 #include <sys/dsl_scan.h>
27 #include <sys/dsl_pool.h>
28 #include <sys/dsl_dataset.h>
29 #include <sys/dsl_prop.h>
30 #include <sys/dsl_dir.h>
31 #include <sys/dsl_synctask.h>
32 #include <sys/dnode.h>
33 #include <sys/dmu_tx.h>
34 #include <sys/dmu_objset.h>
35 #include <sys/arc.h>
36 #include <sys/zap.h>
37 #include <sys/zio.h>
38 #include <sys/zfs_context.h>
39 #include <sys/fs/zfs.h>
40 #include <sys/zfs_znode.h>
41 #include <sys/spa_impl.h>
42 #include <sys/vdev_impl.h>
43 #include <sys/zil_impl.h>
44 #include <sys/zio_checksum.h>
45 #include <sys/ddt.h>
46 #include <sys/sa.h>
47 #include <sys/sa_impl.h>
48 #include <sys/zfeature.h>
49 #ifdef _KERNEL
50 #include <sys/zfs_vfsops.h>
51 #endif
52
53 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *, const zbookmark_t *);
54
55 static scan_cb_t dsl_scan_defrag_cb;
56 static scan_cb_t dsl_scan_scrub_cb;
57 static scan_cb_t dsl_scan_remove_cb;
58 static void dsl_scan_cancel_sync(void *, dmu_tx_t *);
59 static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *tx);
60
61 int zfs_top_maxinflight = 32; /* maximum I/Os per top-level */
62 int zfs_resilver_delay = 2; /* number of ticks to delay resilver */
63 int zfs_scrub_delay = 4; /* number of ticks to delay scrub */
64 int zfs_scan_idle = 50; /* idle window in clock ticks */
65
66 int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
67 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
68 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
69 boolean_t zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
70 boolean_t zfs_no_scrub_prefetch = B_FALSE; /* set to disable srub prefetching */
71 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
72 int dsl_scan_delay_completion = B_FALSE; /* set to delay scan completion */
73 /* max number of blocks to free in a single TXG */
74 uint64_t zfs_free_max_blocks = UINT64_MAX;
75
76 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
77 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
78 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
79
80 extern int zfs_txg_timeout;
81
82 /* the order has to match pool_scan_type */
83 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
84 NULL,
85 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
86 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
87 };
88
89 int
90 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
91 {
92 int err;
93 dsl_scan_t *scn;
94 spa_t *spa = dp->dp_spa;
95 uint64_t f;
96
97 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
98 scn->scn_dp = dp;
99
100 /*
101 * It's possible that we're resuming a scan after a reboot so
102 * make sure that the scan_async_destroying flag is initialized
103 * appropriately.
104 */
105 ASSERT(!scn->scn_async_destroying);
106 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
107 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY]);
108
109 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
110 "scrub_func", sizeof (uint64_t), 1, &f);
111 if (err == 0) {
112 /*
113 * There was an old-style scrub in progress. Restart a
114 * new-style scrub from the beginning.
115 */
116 scn->scn_restart_txg = txg;
117 zfs_dbgmsg("old-style scrub was in progress; "
118 "restarting new-style scrub in txg %llu",
119 scn->scn_restart_txg);
120
121 /*
122 * Load the queue obj from the old location so that it
123 * can be freed by dsl_scan_done().
124 */
125 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
126 "scrub_queue", sizeof (uint64_t), 1,
127 &scn->scn_phys.scn_queue_obj);
128 } else {
129 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
130 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
131 &scn->scn_phys);
132 if (err == ENOENT)
133 return (0);
134 else if (err)
135 return (err);
136
137 if (scn->scn_phys.scn_state == DSS_SCANNING &&
138 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
139 /*
140 * A new-type scrub was in progress on an old
141 * pool, and the pool was accessed by old
142 * software. Restart from the beginning, since
143 * the old software may have changed the pool in
144 * the meantime.
145 */
146 scn->scn_restart_txg = txg;
147 zfs_dbgmsg("new-style scrub was modified "
148 "by old software; restarting in txg %llu",
149 scn->scn_restart_txg);
150 }
151 }
152
153 spa_scan_stat_init(spa);
154 return (0);
155 }
156
157 void
158 dsl_scan_fini(dsl_pool_t *dp)
159 {
160 if (dp->dp_scan) {
161 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
162 dp->dp_scan = NULL;
163 }
164 }
165
166 /* ARGSUSED */
167 static int
168 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
169 {
170 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
171
172 if (scn->scn_phys.scn_state == DSS_SCANNING)
173 return (SET_ERROR(EBUSY));
174
175 return (0);
176 }
177
178 static void
179 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
180 {
181 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
182 pool_scan_func_t *funcp = arg;
183 dmu_object_type_t ot = 0;
184 dsl_pool_t *dp = scn->scn_dp;
185 spa_t *spa = dp->dp_spa;
186
187 ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
188 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
189 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
190 scn->scn_phys.scn_func = *funcp;
191 scn->scn_phys.scn_state = DSS_SCANNING;
192 scn->scn_phys.scn_min_txg = 0;
193 scn->scn_phys.scn_max_txg = tx->tx_txg;
194 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
195 scn->scn_phys.scn_start_time = gethrestime_sec();
196 scn->scn_phys.scn_errors = 0;
197 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
198 scn->scn_restart_txg = 0;
199 spa_scan_stat_init(spa);
200
201 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
202 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
203
204 /* rewrite all disk labels */
205 vdev_config_dirty(spa->spa_root_vdev);
206
207 if (vdev_resilver_needed(spa->spa_root_vdev,
208 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
209 spa_event_notify(spa, NULL, ESC_ZFS_RESILVER_START);
210 } else {
211 spa_event_notify(spa, NULL, ESC_ZFS_SCRUB_START);
212 }
213
214 spa->spa_scrub_started = B_TRUE;
215 /*
216 * If this is an incremental scrub, limit the DDT scrub phase
217 * to just the auto-ditto class (for correctness); the rest
218 * of the scrub should go faster using top-down pruning.
219 */
220 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
221 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
222
223 }
224
225 /* back to the generic stuff */
226
227 if (dp->dp_blkstats == NULL) {
228 dp->dp_blkstats =
229 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
230 }
231 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
232
233 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
234 ot = DMU_OT_ZAP_OTHER;
235
236 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
237 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
238
239 dsl_scan_sync_state(scn, tx);
240
241 spa_history_log_internal(spa, "scan setup", tx,
242 "func=%u mintxg=%llu maxtxg=%llu",
243 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
244 }
245
246 /* ARGSUSED */
247 static void
248 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
249 {
250 static const char *old_names[] = {
251 "scrub_bookmark",
252 "scrub_ddt_bookmark",
253 "scrub_ddt_class_max",
254 "scrub_queue",
255 "scrub_min_txg",
256 "scrub_max_txg",
257 "scrub_func",
258 "scrub_errors",
259 NULL
260 };
261
262 dsl_pool_t *dp = scn->scn_dp;
263 spa_t *spa = dp->dp_spa;
264 int i;
265
266 /* Remove any remnants of an old-style scrub. */
267 for (i = 0; old_names[i]; i++) {
268 (void) zap_remove(dp->dp_meta_objset,
269 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
270 }
271
272 if (scn->scn_phys.scn_queue_obj != 0) {
273 VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
274 scn->scn_phys.scn_queue_obj, tx));
275 scn->scn_phys.scn_queue_obj = 0;
276 }
277
278 /*
279 * If we were "restarted" from a stopped state, don't bother
280 * with anything else.
281 */
282 if (scn->scn_phys.scn_state != DSS_SCANNING)
283 return;
284
285 if (complete)
286 scn->scn_phys.scn_state = DSS_FINISHED;
287 else
288 scn->scn_phys.scn_state = DSS_CANCELED;
289
290 spa_history_log_internal(spa, "scan done", tx,
291 "complete=%u", complete);
292
293 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
294 mutex_enter(&spa->spa_scrub_lock);
295 while (spa->spa_scrub_inflight > 0) {
296 cv_wait(&spa->spa_scrub_io_cv,
297 &spa->spa_scrub_lock);
298 }
299 mutex_exit(&spa->spa_scrub_lock);
300 spa->spa_scrub_started = B_FALSE;
301 spa->spa_scrub_active = B_FALSE;
302
303 /*
304 * If the scrub/resilver completed, update all DTLs to
305 * reflect this. Whether it succeeded or not, vacate
306 * all temporary scrub DTLs.
307 */
308 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
309 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
310 if (complete) {
311 spa_event_notify(spa, NULL, scn->scn_phys.scn_min_txg ?
312 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
313 }
314 spa_errlog_rotate(spa);
315
316 /*
317 * We may have finished replacing a device.
318 * Let the async thread assess this and handle the detach.
319 */
320 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
321 }
322
323 scn->scn_phys.scn_end_time = gethrestime_sec();
324 }
325
326 /* ARGSUSED */
327 static int
328 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
329 {
330 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
331
332 if (scn->scn_phys.scn_state != DSS_SCANNING)
333 return (SET_ERROR(ENOENT));
334 return (0);
335 }
336
337 /* ARGSUSED */
338 static void
339 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
340 {
341 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
342
343 dsl_scan_done(scn, B_FALSE, tx);
344 dsl_scan_sync_state(scn, tx);
345 }
346
347 int
348 dsl_scan_cancel(dsl_pool_t *dp)
349 {
350 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
351 dsl_scan_cancel_sync, NULL, 3));
352 }
353
354 static void dsl_scan_visitbp(blkptr_t *bp,
355 const zbookmark_t *zb, dnode_phys_t *dnp, arc_buf_t *pbuf,
356 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
357 dmu_tx_t *tx);
358 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
359 dmu_objset_type_t ostype,
360 dnode_phys_t *dnp, arc_buf_t *buf, uint64_t object, dmu_tx_t *tx);
361
362 void
363 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
364 {
365 zio_free(dp->dp_spa, txg, bp);
366 }
367
368 void
369 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
370 {
371 ASSERT(dsl_pool_sync_context(dp));
372 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
373 }
374
375 static uint64_t
376 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
377 {
378 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
379 if (dsl_dataset_is_snapshot(ds))
380 return (MIN(smt, ds->ds_phys->ds_creation_txg));
381 return (smt);
382 }
383
384 static void
385 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
386 {
387 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
388 DMU_POOL_DIRECTORY_OBJECT,
389 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
390 &scn->scn_phys, tx));
391 }
392
393 static boolean_t
394 dsl_scan_check_pause(dsl_scan_t *scn, const zbookmark_t *zb)
395 {
396 uint64_t elapsed_nanosecs;
397 int mintime;
398
399 /* we never skip user/group accounting objects */
400 if (zb && (int64_t)zb->zb_object < 0)
401 return (B_FALSE);
402
403 if (scn->scn_pausing)
404 return (B_TRUE); /* we're already pausing */
405
406 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
407 return (B_FALSE); /* we're resuming */
408
409 /* We only know how to resume from level-0 blocks. */
410 if (zb && zb->zb_level != 0)
411 return (B_FALSE);
412
413 mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
414 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
415 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
416 if (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
417 (NSEC2MSEC(elapsed_nanosecs) > mintime &&
418 txg_sync_waiting(scn->scn_dp)) ||
419 spa_shutting_down(scn->scn_dp->dp_spa)) {
420 if (zb) {
421 dprintf("pausing at bookmark %llx/%llx/%llx/%llx\n",
422 (longlong_t)zb->zb_objset,
423 (longlong_t)zb->zb_object,
424 (longlong_t)zb->zb_level,
425 (longlong_t)zb->zb_blkid);
426 scn->scn_phys.scn_bookmark = *zb;
427 }
428 dprintf("pausing at DDT bookmark %llx/%llx/%llx/%llx\n",
429 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
430 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
431 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
432 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
433 scn->scn_pausing = B_TRUE;
434 return (B_TRUE);
435 }
436 return (B_FALSE);
437 }
438
439 typedef struct zil_scan_arg {
440 dsl_pool_t *zsa_dp;
441 zil_header_t *zsa_zh;
442 } zil_scan_arg_t;
443
444 /* ARGSUSED */
445 static int
446 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
447 {
448 zil_scan_arg_t *zsa = arg;
449 dsl_pool_t *dp = zsa->zsa_dp;
450 dsl_scan_t *scn = dp->dp_scan;
451 zil_header_t *zh = zsa->zsa_zh;
452 zbookmark_t zb;
453
454 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
455 return (0);
456
457 /*
458 * One block ("stubby") can be allocated a long time ago; we
459 * want to visit that one because it has been allocated
460 * (on-disk) even if it hasn't been claimed (even though for
461 * scrub there's nothing to do to it).
462 */
463 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(dp->dp_spa))
464 return (0);
465
466 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
467 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
468
469 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
470 return (0);
471 }
472
473 /* ARGSUSED */
474 static int
475 dsl_scan_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
476 {
477 if (lrc->lrc_txtype == TX_WRITE) {
478 zil_scan_arg_t *zsa = arg;
479 dsl_pool_t *dp = zsa->zsa_dp;
480 dsl_scan_t *scn = dp->dp_scan;
481 zil_header_t *zh = zsa->zsa_zh;
482 lr_write_t *lr = (lr_write_t *)lrc;
483 blkptr_t *bp = &lr->lr_blkptr;
484 zbookmark_t zb;
485
486 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
487 return (0);
488
489 /*
490 * birth can be < claim_txg if this record's txg is
491 * already txg sync'ed (but this log block contains
492 * other records that are not synced)
493 */
494 if (claim_txg == 0 || bp->blk_birth < claim_txg)
495 return (0);
496
497 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
498 lr->lr_foid, ZB_ZIL_LEVEL,
499 lr->lr_offset / BP_GET_LSIZE(bp));
500
501 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
502 }
503 return (0);
504 }
505
506 static void
507 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
508 {
509 uint64_t claim_txg = zh->zh_claim_txg;
510 zil_scan_arg_t zsa = { dp, zh };
511 zilog_t *zilog;
512
513 /*
514 * We only want to visit blocks that have been claimed but not yet
515 * replayed (or, in read-only mode, blocks that *would* be claimed).
516 */
517 if (claim_txg == 0 && spa_writeable(dp->dp_spa))
518 return;
519
520 zilog = zil_alloc(dp->dp_meta_objset, zh);
521
522 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
523 claim_txg);
524
525 zil_free(zilog);
526 }
527
528 /* ARGSUSED */
529 static void
530 dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
531 uint64_t objset, uint64_t object, uint64_t blkid)
532 {
533 zbookmark_t czb;
534 uint32_t flags = ARC_NOWAIT | ARC_PREFETCH;
535
536 if (zfs_no_scrub_prefetch)
537 return;
538
539 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_min_txg ||
540 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE))
541 return;
542
543 SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
544
545 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
546 NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
547 ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
548 }
549
550 static boolean_t
551 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
552 const zbookmark_t *zb)
553 {
554 /*
555 * We never skip over user/group accounting objects (obj<0)
556 */
557 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
558 (int64_t)zb->zb_object >= 0) {
559 /*
560 * If we already visited this bp & everything below (in
561 * a prior txg sync), don't bother doing it again.
562 */
563 if (zbookmark_is_before(dnp, zb, &scn->scn_phys.scn_bookmark))
564 return (B_TRUE);
565
566 /*
567 * If we found the block we're trying to resume from, or
568 * we went past it to a different object, zero it out to
569 * indicate that it's OK to start checking for pausing
570 * again.
571 */
572 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
573 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
574 dprintf("resuming at %llx/%llx/%llx/%llx\n",
575 (longlong_t)zb->zb_objset,
576 (longlong_t)zb->zb_object,
577 (longlong_t)zb->zb_level,
578 (longlong_t)zb->zb_blkid);
579 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
580 }
581 }
582 return (B_FALSE);
583 }
584
585 /*
586 * Return nonzero on i/o error.
587 * Return new buf to write out in *bufp.
588 */
589 static int
590 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
591 dnode_phys_t *dnp, const blkptr_t *bp,
592 const zbookmark_t *zb, dmu_tx_t *tx, arc_buf_t **bufp)
593 {
594 dsl_pool_t *dp = scn->scn_dp;
595 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
596 int err;
597
598 if (BP_GET_LEVEL(bp) > 0) {
599 uint32_t flags = ARC_WAIT;
600 int i;
601 blkptr_t *cbp;
602 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
603
604 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
605 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
606 if (err) {
607 scn->scn_phys.scn_errors++;
608 return (err);
609 }
610 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
611 dsl_scan_prefetch(scn, *bufp, cbp, zb->zb_objset,
612 zb->zb_object, zb->zb_blkid * epb + i);
613 }
614 for (i = 0, cbp = (*bufp)->b_data; i < epb; i++, cbp++) {
615 zbookmark_t czb;
616
617 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
618 zb->zb_level - 1,
619 zb->zb_blkid * epb + i);
620 dsl_scan_visitbp(cbp, &czb, dnp,
621 *bufp, ds, scn, ostype, tx);
622 }
623 } else if (BP_GET_TYPE(bp) == DMU_OT_USERGROUP_USED) {
624 uint32_t flags = ARC_WAIT;
625
626 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
627 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
628 if (err) {
629 scn->scn_phys.scn_errors++;
630 return (err);
631 }
632 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
633 uint32_t flags = ARC_WAIT;
634 dnode_phys_t *cdnp;
635 int i, j;
636 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
637
638 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
639 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
640 if (err) {
641 scn->scn_phys.scn_errors++;
642 return (err);
643 }
644 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
645 for (j = 0; j < cdnp->dn_nblkptr; j++) {
646 blkptr_t *cbp = &cdnp->dn_blkptr[j];
647 dsl_scan_prefetch(scn, *bufp, cbp,
648 zb->zb_objset, zb->zb_blkid * epb + i, j);
649 }
650 }
651 for (i = 0, cdnp = (*bufp)->b_data; i < epb; i++, cdnp++) {
652 dsl_scan_visitdnode(scn, ds, ostype,
653 cdnp, *bufp, zb->zb_blkid * epb + i, tx);
654 }
655
656 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
657 uint32_t flags = ARC_WAIT;
658 objset_phys_t *osp;
659
660 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, bufp,
661 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
662 if (err) {
663 scn->scn_phys.scn_errors++;
664 return (err);
665 }
666
667 osp = (*bufp)->b_data;
668
669 dsl_scan_visitdnode(scn, ds, osp->os_type,
670 &osp->os_meta_dnode, *bufp, DMU_META_DNODE_OBJECT, tx);
671
672 if (OBJSET_BUF_HAS_USERUSED(*bufp)) {
673 /*
674 * We also always visit user/group accounting
675 * objects, and never skip them, even if we are
676 * pausing. This is necessary so that the space
677 * deltas from this txg get integrated.
678 */
679 dsl_scan_visitdnode(scn, ds, osp->os_type,
680 &osp->os_groupused_dnode, *bufp,
681 DMU_GROUPUSED_OBJECT, tx);
682 dsl_scan_visitdnode(scn, ds, osp->os_type,
683 &osp->os_userused_dnode, *bufp,
684 DMU_USERUSED_OBJECT, tx);
685 }
686 }
687
688 return (0);
689 }
690
691 static void
692 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
693 dmu_objset_type_t ostype, dnode_phys_t *dnp, arc_buf_t *buf,
694 uint64_t object, dmu_tx_t *tx)
695 {
696 int j;
697
698 for (j = 0; j < dnp->dn_nblkptr; j++) {
699 zbookmark_t czb;
700
701 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
702 dnp->dn_nlevels - 1, j);
703 dsl_scan_visitbp(&dnp->dn_blkptr[j],
704 &czb, dnp, buf, ds, scn, ostype, tx);
705 }
706
707 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
708 zbookmark_t czb;
709 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
710 0, DMU_SPILL_BLKID);
711 dsl_scan_visitbp(&dnp->dn_spill,
712 &czb, dnp, buf, ds, scn, ostype, tx);
713 }
714 }
715
716 /*
717 * The arguments are in this order because mdb can only print the
718 * first 5; we want them to be useful.
719 */
720 static void
721 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_t *zb,
722 dnode_phys_t *dnp, arc_buf_t *pbuf,
723 dsl_dataset_t *ds, dsl_scan_t *scn, dmu_objset_type_t ostype,
724 dmu_tx_t *tx)
725 {
726 dsl_pool_t *dp = scn->scn_dp;
727 arc_buf_t *buf = NULL;
728 blkptr_t bp_toread = *bp;
729
730 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
731
732 if (dsl_scan_check_pause(scn, zb))
733 return;
734
735 if (dsl_scan_check_resume(scn, dnp, zb))
736 return;
737
738 if (bp->blk_birth == 0)
739 return;
740
741 scn->scn_visited_this_txg++;
742
743 dprintf_bp(bp,
744 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx buf=%p bp=%p",
745 ds, ds ? ds->ds_object : 0,
746 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
747 pbuf, bp);
748
749 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
750 return;
751
752 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx,
753 &buf) != 0)
754 return;
755
756 /*
757 * If dsl_scan_ddt() has aready visited this block, it will have
758 * already done any translations or scrubbing, so don't call the
759 * callback again.
760 */
761 if (ddt_class_contains(dp->dp_spa,
762 scn->scn_phys.scn_ddt_class_max, bp)) {
763 ASSERT(buf == NULL);
764 return;
765 }
766
767 /*
768 * If this block is from the future (after cur_max_txg), then we
769 * are doing this on behalf of a deleted snapshot, and we will
770 * revisit the future block on the next pass of this dataset.
771 * Don't scan it now unless we need to because something
772 * under it was modified.
773 */
774 if (bp->blk_birth <= scn->scn_phys.scn_cur_max_txg) {
775 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
776 }
777 if (buf)
778 (void) arc_buf_remove_ref(buf, &buf);
779 }
780
781 static void
782 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
783 dmu_tx_t *tx)
784 {
785 zbookmark_t zb;
786
787 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
788 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
789 dsl_scan_visitbp(bp, &zb, NULL, NULL,
790 ds, scn, DMU_OST_NONE, tx);
791
792 dprintf_ds(ds, "finished scan%s", "");
793 }
794
795 void
796 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
797 {
798 dsl_pool_t *dp = ds->ds_dir->dd_pool;
799 dsl_scan_t *scn = dp->dp_scan;
800 uint64_t mintxg;
801
802 if (scn->scn_phys.scn_state != DSS_SCANNING)
803 return;
804
805 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
806 if (dsl_dataset_is_snapshot(ds)) {
807 /* Note, scn_cur_{min,max}_txg stays the same. */
808 scn->scn_phys.scn_bookmark.zb_objset =
809 ds->ds_phys->ds_next_snap_obj;
810 zfs_dbgmsg("destroying ds %llu; currently traversing; "
811 "reset zb_objset to %llu",
812 (u_longlong_t)ds->ds_object,
813 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
814 scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
815 } else {
816 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
817 ZB_DESTROYED_OBJSET, 0, 0, 0);
818 zfs_dbgmsg("destroying ds %llu; currently traversing; "
819 "reset bookmark to -1,0,0,0",
820 (u_longlong_t)ds->ds_object);
821 }
822 } else if (zap_lookup_int_key(dp->dp_meta_objset,
823 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
824 ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
825 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
826 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
827 if (dsl_dataset_is_snapshot(ds)) {
828 /*
829 * We keep the same mintxg; it could be >
830 * ds_creation_txg if the previous snapshot was
831 * deleted too.
832 */
833 VERIFY(zap_add_int_key(dp->dp_meta_objset,
834 scn->scn_phys.scn_queue_obj,
835 ds->ds_phys->ds_next_snap_obj, mintxg, tx) == 0);
836 zfs_dbgmsg("destroying ds %llu; in queue; "
837 "replacing with %llu",
838 (u_longlong_t)ds->ds_object,
839 (u_longlong_t)ds->ds_phys->ds_next_snap_obj);
840 } else {
841 zfs_dbgmsg("destroying ds %llu; in queue; removing",
842 (u_longlong_t)ds->ds_object);
843 }
844 } else {
845 zfs_dbgmsg("destroying ds %llu; ignoring",
846 (u_longlong_t)ds->ds_object);
847 }
848
849 /*
850 * dsl_scan_sync() should be called after this, and should sync
851 * out our changed state, but just to be safe, do it here.
852 */
853 dsl_scan_sync_state(scn, tx);
854 }
855
856 void
857 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
858 {
859 dsl_pool_t *dp = ds->ds_dir->dd_pool;
860 dsl_scan_t *scn = dp->dp_scan;
861 uint64_t mintxg;
862
863 if (scn->scn_phys.scn_state != DSS_SCANNING)
864 return;
865
866 ASSERT(ds->ds_phys->ds_prev_snap_obj != 0);
867
868 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
869 scn->scn_phys.scn_bookmark.zb_objset =
870 ds->ds_phys->ds_prev_snap_obj;
871 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
872 "reset zb_objset to %llu",
873 (u_longlong_t)ds->ds_object,
874 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
875 } else if (zap_lookup_int_key(dp->dp_meta_objset,
876 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
877 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
878 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
879 VERIFY(zap_add_int_key(dp->dp_meta_objset,
880 scn->scn_phys.scn_queue_obj,
881 ds->ds_phys->ds_prev_snap_obj, mintxg, tx) == 0);
882 zfs_dbgmsg("snapshotting ds %llu; in queue; "
883 "replacing with %llu",
884 (u_longlong_t)ds->ds_object,
885 (u_longlong_t)ds->ds_phys->ds_prev_snap_obj);
886 }
887 dsl_scan_sync_state(scn, tx);
888 }
889
890 void
891 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
892 {
893 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
894 dsl_scan_t *scn = dp->dp_scan;
895 uint64_t mintxg;
896
897 if (scn->scn_phys.scn_state != DSS_SCANNING)
898 return;
899
900 if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
901 scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
902 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
903 "reset zb_objset to %llu",
904 (u_longlong_t)ds1->ds_object,
905 (u_longlong_t)ds2->ds_object);
906 } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
907 scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
908 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
909 "reset zb_objset to %llu",
910 (u_longlong_t)ds2->ds_object,
911 (u_longlong_t)ds1->ds_object);
912 }
913
914 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
915 ds1->ds_object, &mintxg) == 0) {
916 int err;
917
918 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
919 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
920 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
921 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
922 err = zap_add_int_key(dp->dp_meta_objset,
923 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
924 VERIFY(err == 0 || err == EEXIST);
925 if (err == EEXIST) {
926 /* Both were there to begin with */
927 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
928 scn->scn_phys.scn_queue_obj,
929 ds1->ds_object, mintxg, tx));
930 }
931 zfs_dbgmsg("clone_swap ds %llu; in queue; "
932 "replacing with %llu",
933 (u_longlong_t)ds1->ds_object,
934 (u_longlong_t)ds2->ds_object);
935 } else if (zap_lookup_int_key(dp->dp_meta_objset,
936 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
937 ASSERT3U(mintxg, ==, ds1->ds_phys->ds_prev_snap_txg);
938 ASSERT3U(mintxg, ==, ds2->ds_phys->ds_prev_snap_txg);
939 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
940 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
941 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
942 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
943 zfs_dbgmsg("clone_swap ds %llu; in queue; "
944 "replacing with %llu",
945 (u_longlong_t)ds2->ds_object,
946 (u_longlong_t)ds1->ds_object);
947 }
948
949 dsl_scan_sync_state(scn, tx);
950 }
951
952 struct enqueue_clones_arg {
953 dmu_tx_t *tx;
954 uint64_t originobj;
955 };
956
957 /* ARGSUSED */
958 static int
959 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
960 {
961 struct enqueue_clones_arg *eca = arg;
962 dsl_dataset_t *ds;
963 int err;
964 dsl_scan_t *scn = dp->dp_scan;
965
966 if (hds->ds_dir->dd_phys->dd_origin_obj != eca->originobj)
967 return (0);
968
969 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
970 if (err)
971 return (err);
972
973 while (ds->ds_phys->ds_prev_snap_obj != eca->originobj) {
974 dsl_dataset_t *prev;
975 err = dsl_dataset_hold_obj(dp,
976 ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
977
978 dsl_dataset_rele(ds, FTAG);
979 if (err)
980 return (err);
981 ds = prev;
982 }
983 VERIFY(zap_add_int_key(dp->dp_meta_objset,
984 scn->scn_phys.scn_queue_obj, ds->ds_object,
985 ds->ds_phys->ds_prev_snap_txg, eca->tx) == 0);
986 dsl_dataset_rele(ds, FTAG);
987 return (0);
988 }
989
990 static void
991 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
992 {
993 dsl_pool_t *dp = scn->scn_dp;
994 dsl_dataset_t *ds;
995 objset_t *os;
996
997 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
998
999 if (dmu_objset_from_ds(ds, &os))
1000 goto out;
1001
1002 /*
1003 * Only the ZIL in the head (non-snapshot) is valid. Even though
1004 * snapshots can have ZIL block pointers (which may be the same
1005 * BP as in the head), they must be ignored. So we traverse the
1006 * ZIL here, rather than in scan_recurse(), because the regular
1007 * snapshot block-sharing rules don't apply to it.
1008 */
1009 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !dsl_dataset_is_snapshot(ds))
1010 dsl_scan_zil(dp, &os->os_zil_header);
1011
1012 /*
1013 * Iterate over the bps in this ds.
1014 */
1015 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1016 dsl_scan_visit_rootbp(scn, ds, &ds->ds_phys->ds_bp, tx);
1017
1018 char *dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
1019 dsl_dataset_name(ds, dsname);
1020 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1021 "pausing=%u",
1022 (longlong_t)dsobj, dsname,
1023 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1024 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1025 (int)scn->scn_pausing);
1026 kmem_free(dsname, ZFS_MAXNAMELEN);
1027
1028 if (scn->scn_pausing)
1029 goto out;
1030
1031 /*
1032 * We've finished this pass over this dataset.
1033 */
1034
1035 /*
1036 * If we did not completely visit this dataset, do another pass.
1037 */
1038 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1039 zfs_dbgmsg("incomplete pass; visiting again");
1040 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1041 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1042 scn->scn_phys.scn_queue_obj, ds->ds_object,
1043 scn->scn_phys.scn_cur_max_txg, tx) == 0);
1044 goto out;
1045 }
1046
1047 /*
1048 * Add descendent datasets to work queue.
1049 */
1050 if (ds->ds_phys->ds_next_snap_obj != 0) {
1051 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1052 scn->scn_phys.scn_queue_obj, ds->ds_phys->ds_next_snap_obj,
1053 ds->ds_phys->ds_creation_txg, tx) == 0);
1054 }
1055 if (ds->ds_phys->ds_num_children > 1) {
1056 boolean_t usenext = B_FALSE;
1057 if (ds->ds_phys->ds_next_clones_obj != 0) {
1058 uint64_t count;
1059 /*
1060 * A bug in a previous version of the code could
1061 * cause upgrade_clones_cb() to not set
1062 * ds_next_snap_obj when it should, leading to a
1063 * missing entry. Therefore we can only use the
1064 * next_clones_obj when its count is correct.
1065 */
1066 int err = zap_count(dp->dp_meta_objset,
1067 ds->ds_phys->ds_next_clones_obj, &count);
1068 if (err == 0 &&
1069 count == ds->ds_phys->ds_num_children - 1)
1070 usenext = B_TRUE;
1071 }
1072
1073 if (usenext) {
1074 VERIFY0(zap_join_key(dp->dp_meta_objset,
1075 ds->ds_phys->ds_next_clones_obj,
1076 scn->scn_phys.scn_queue_obj,
1077 ds->ds_phys->ds_creation_txg, tx));
1078 } else {
1079 struct enqueue_clones_arg eca;
1080 eca.tx = tx;
1081 eca.originobj = ds->ds_object;
1082
1083 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1084 enqueue_clones_cb, &eca, DS_FIND_CHILDREN));
1085 }
1086 }
1087
1088 out:
1089 dsl_dataset_rele(ds, FTAG);
1090 }
1091
1092 /* ARGSUSED */
1093 static int
1094 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1095 {
1096 dmu_tx_t *tx = arg;
1097 dsl_dataset_t *ds;
1098 int err;
1099 dsl_scan_t *scn = dp->dp_scan;
1100
1101 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1102 if (err)
1103 return (err);
1104
1105 while (ds->ds_phys->ds_prev_snap_obj != 0) {
1106 dsl_dataset_t *prev;
1107 err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
1108 FTAG, &prev);
1109 if (err) {
1110 dsl_dataset_rele(ds, FTAG);
1111 return (err);
1112 }
1113
1114 /*
1115 * If this is a clone, we don't need to worry about it for now.
1116 */
1117 if (prev->ds_phys->ds_next_snap_obj != ds->ds_object) {
1118 dsl_dataset_rele(ds, FTAG);
1119 dsl_dataset_rele(prev, FTAG);
1120 return (0);
1121 }
1122 dsl_dataset_rele(ds, FTAG);
1123 ds = prev;
1124 }
1125
1126 VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1127 ds->ds_object, ds->ds_phys->ds_prev_snap_txg, tx) == 0);
1128 dsl_dataset_rele(ds, FTAG);
1129 return (0);
1130 }
1131
1132 /*
1133 * Scrub/dedup interaction.
1134 *
1135 * If there are N references to a deduped block, we don't want to scrub it
1136 * N times -- ideally, we should scrub it exactly once.
1137 *
1138 * We leverage the fact that the dde's replication class (enum ddt_class)
1139 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1140 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1141 *
1142 * To prevent excess scrubbing, the scrub begins by walking the DDT
1143 * to find all blocks with refcnt > 1, and scrubs each of these once.
1144 * Since there are two replication classes which contain blocks with
1145 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1146 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1147 *
1148 * There would be nothing more to say if a block's refcnt couldn't change
1149 * during a scrub, but of course it can so we must account for changes
1150 * in a block's replication class.
1151 *
1152 * Here's an example of what can occur:
1153 *
1154 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
1155 * when visited during the top-down scrub phase, it will be scrubbed twice.
1156 * This negates our scrub optimization, but is otherwise harmless.
1157 *
1158 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1159 * on each visit during the top-down scrub phase, it will never be scrubbed.
1160 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1161 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1162 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1163 * while a scrub is in progress, it scrubs the block right then.
1164 */
1165 static void
1166 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1167 {
1168 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1169 ddt_entry_t dde = { 0 };
1170 int error;
1171 uint64_t n = 0;
1172
1173 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1174 ddt_t *ddt;
1175
1176 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1177 break;
1178 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1179 (longlong_t)ddb->ddb_class,
1180 (longlong_t)ddb->ddb_type,
1181 (longlong_t)ddb->ddb_checksum,
1182 (longlong_t)ddb->ddb_cursor);
1183
1184 /* There should be no pending changes to the dedup table */
1185 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1186 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
1187
1188 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1189 n++;
1190
1191 if (dsl_scan_check_pause(scn, NULL))
1192 break;
1193 }
1194
1195 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; pausing=%u",
1196 (longlong_t)n, (int)scn->scn_phys.scn_ddt_class_max,
1197 (int)scn->scn_pausing);
1198
1199 ASSERT(error == 0 || error == ENOENT);
1200 ASSERT(error != ENOENT ||
1201 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1202 }
1203
1204 /* ARGSUSED */
1205 void
1206 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1207 ddt_entry_t *dde, dmu_tx_t *tx)
1208 {
1209 const ddt_key_t *ddk = &dde->dde_key;
1210 ddt_phys_t *ddp = dde->dde_phys;
1211 blkptr_t bp;
1212 zbookmark_t zb = { 0 };
1213
1214 if (scn->scn_phys.scn_state != DSS_SCANNING)
1215 return;
1216
1217 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1218 if (ddp->ddp_phys_birth == 0 ||
1219 ddp->ddp_phys_birth > scn->scn_phys.scn_cur_max_txg)
1220 continue;
1221 ddt_bp_create(checksum, ddk, ddp, &bp);
1222
1223 scn->scn_visited_this_txg++;
1224 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1225 }
1226 }
1227
1228 static void
1229 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1230 {
1231 dsl_pool_t *dp = scn->scn_dp;
1232 zap_cursor_t zc;
1233 zap_attribute_t za;
1234
1235 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1236 scn->scn_phys.scn_ddt_class_max) {
1237 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1238 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1239 dsl_scan_ddt(scn, tx);
1240 if (scn->scn_pausing)
1241 return;
1242 }
1243
1244 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1245 /* First do the MOS & ORIGIN */
1246
1247 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1248 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1249 dsl_scan_visit_rootbp(scn, NULL,
1250 &dp->dp_meta_rootbp, tx);
1251 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1252 if (scn->scn_pausing)
1253 return;
1254
1255 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1256 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1257 enqueue_cb, tx, DS_FIND_CHILDREN));
1258 } else {
1259 dsl_scan_visitds(scn,
1260 dp->dp_origin_snap->ds_object, tx);
1261 }
1262 ASSERT(!scn->scn_pausing);
1263 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
1264 ZB_DESTROYED_OBJSET) {
1265 /*
1266 * If we were paused, continue from here. Note if the
1267 * ds we were paused on was deleted, the zb_objset may
1268 * be -1, so we will skip this and find a new objset
1269 * below.
1270 */
1271 dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
1272 if (scn->scn_pausing)
1273 return;
1274 }
1275
1276 /*
1277 * In case we were paused right at the end of the ds, zero the
1278 * bookmark so we don't think that we're still trying to resume.
1279 */
1280 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_t));
1281
1282 /* keep pulling things out of the zap-object-as-queue */
1283 while (zap_cursor_init(&zc, dp->dp_meta_objset,
1284 scn->scn_phys.scn_queue_obj),
1285 zap_cursor_retrieve(&zc, &za) == 0) {
1286 dsl_dataset_t *ds;
1287 uint64_t dsobj;
1288
1289 dsobj = strtonum(za.za_name, NULL);
1290 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1291 scn->scn_phys.scn_queue_obj, dsobj, tx));
1292
1293 /* Set up min/max txg */
1294 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1295 if (za.za_first_integer != 0) {
1296 scn->scn_phys.scn_cur_min_txg =
1297 MAX(scn->scn_phys.scn_min_txg,
1298 za.za_first_integer);
1299 } else {
1300 scn->scn_phys.scn_cur_min_txg =
1301 MAX(scn->scn_phys.scn_min_txg,
1302 ds->ds_phys->ds_prev_snap_txg);
1303 }
1304 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
1305 dsl_dataset_rele(ds, FTAG);
1306
1307 dsl_scan_visitds(scn, dsobj, tx);
1308 zap_cursor_fini(&zc);
1309 if (scn->scn_pausing)
1310 return;
1311 }
1312 zap_cursor_fini(&zc);
1313 }
1314
1315 static boolean_t
1316 dsl_scan_free_should_pause(dsl_scan_t *scn)
1317 {
1318 uint64_t elapsed_nanosecs;
1319
1320 if (scn->scn_visited_this_txg >= zfs_free_max_blocks)
1321 return (B_TRUE);
1322
1323 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
1324 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
1325 (NSEC2MSEC(elapsed_nanosecs) > zfs_free_min_time_ms &&
1326 txg_sync_waiting(scn->scn_dp)) ||
1327 spa_shutting_down(scn->scn_dp->dp_spa));
1328 }
1329
1330 static int
1331 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1332 {
1333 dsl_scan_t *scn = arg;
1334
1335 if (!scn->scn_is_bptree ||
1336 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
1337 if (dsl_scan_free_should_pause(scn))
1338 return (SET_ERROR(ERESTART));
1339 }
1340
1341 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
1342 dmu_tx_get_txg(tx), bp, 0));
1343 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
1344 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
1345 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
1346 scn->scn_visited_this_txg++;
1347 return (0);
1348 }
1349
1350 boolean_t
1351 dsl_scan_active(dsl_scan_t *scn)
1352 {
1353 spa_t *spa = scn->scn_dp->dp_spa;
1354 uint64_t used = 0, comp, uncomp;
1355
1356 if (spa->spa_load_state != SPA_LOAD_NONE)
1357 return (B_FALSE);
1358 if (spa_shutting_down(spa))
1359 return (B_FALSE);
1360
1361 if (scn->scn_phys.scn_state == DSS_SCANNING ||
1362 scn->scn_async_destroying)
1363 return (B_TRUE);
1364
1365 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1366 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
1367 &used, &comp, &uncomp);
1368 }
1369 return (used != 0);
1370 }
1371
1372 void
1373 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
1374 {
1375 dsl_scan_t *scn = dp->dp_scan;
1376 spa_t *spa = dp->dp_spa;
1377 int err;
1378
1379 /*
1380 * Check for scn_restart_txg before checking spa_load_state, so
1381 * that we can restart an old-style scan while the pool is being
1382 * imported (see dsl_scan_init).
1383 */
1384 if (scn->scn_restart_txg != 0 &&
1385 scn->scn_restart_txg <= tx->tx_txg) {
1386 pool_scan_func_t func = POOL_SCAN_SCRUB;
1387 dsl_scan_done(scn, B_FALSE, tx);
1388 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
1389 func = POOL_SCAN_RESILVER;
1390 zfs_dbgmsg("restarting scan func=%u txg=%llu",
1391 func, tx->tx_txg);
1392 dsl_scan_setup_sync(&func, tx);
1393 }
1394
1395 if (!dsl_scan_active(scn) ||
1396 spa_sync_pass(dp->dp_spa) > 1)
1397 return;
1398
1399 scn->scn_visited_this_txg = 0;
1400 scn->scn_pausing = B_FALSE;
1401 scn->scn_sync_start_time = gethrtime();
1402 spa->spa_scrub_active = B_TRUE;
1403
1404 /*
1405 * First process the free list. If we pause the free, don't do
1406 * any scanning. This ensures that there is no free list when
1407 * we are scanning, so the scan code doesn't have to worry about
1408 * traversing it.
1409 */
1410 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1411 scn->scn_is_bptree = B_FALSE;
1412 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1413 NULL, ZIO_FLAG_MUSTSUCCEED);
1414 err = bpobj_iterate(&dp->dp_free_bpobj,
1415 dsl_scan_free_block_cb, scn, tx);
1416 VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
1417
1418 if (err == 0 && spa_feature_is_active(spa,
1419 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
1420 ASSERT(scn->scn_async_destroying);
1421 scn->scn_is_bptree = B_TRUE;
1422 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1423 NULL, ZIO_FLAG_MUSTSUCCEED);
1424 err = bptree_iterate(dp->dp_meta_objset,
1425 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb,
1426 scn, tx);
1427 VERIFY0(zio_wait(scn->scn_zio_root));
1428
1429 if (err == 0) {
1430 zfeature_info_t *feat = &spa_feature_table
1431 [SPA_FEATURE_ASYNC_DESTROY];
1432 /* finished; deactivate async destroy feature */
1433 spa_feature_decr(spa, feat, tx);
1434 ASSERT(!spa_feature_is_active(spa, feat));
1435 VERIFY0(zap_remove(dp->dp_meta_objset,
1436 DMU_POOL_DIRECTORY_OBJECT,
1437 DMU_POOL_BPTREE_OBJ, tx));
1438 VERIFY0(bptree_free(dp->dp_meta_objset,
1439 dp->dp_bptree_obj, tx));
1440 dp->dp_bptree_obj = 0;
1441 scn->scn_async_destroying = B_FALSE;
1442 }
1443 }
1444 if (scn->scn_visited_this_txg) {
1445 zfs_dbgmsg("freed %llu blocks in %llums from "
1446 "free_bpobj/bptree txg %llu",
1447 (longlong_t)scn->scn_visited_this_txg,
1448 (longlong_t)
1449 NSEC2MSEC(gethrtime() - scn->scn_sync_start_time),
1450 (longlong_t)tx->tx_txg);
1451 scn->scn_visited_this_txg = 0;
1452 /*
1453 * Re-sync the ddt so that we can further modify
1454 * it when doing bprewrite.
1455 */
1456 ddt_sync(spa, tx->tx_txg);
1457 }
1458 if (err == ERESTART)
1459 return;
1460 }
1461
1462 if (scn->scn_phys.scn_state != DSS_SCANNING)
1463 return;
1464
1465 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1466 scn->scn_phys.scn_ddt_class_max) {
1467 zfs_dbgmsg("doing scan sync txg %llu; "
1468 "ddt bm=%llu/%llu/%llu/%llx",
1469 (longlong_t)tx->tx_txg,
1470 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1471 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1472 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1473 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1474 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
1475 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
1476 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
1477 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
1478 } else {
1479 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
1480 (longlong_t)tx->tx_txg,
1481 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
1482 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
1483 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
1484 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
1485 }
1486
1487 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1488 NULL, ZIO_FLAG_CANFAIL);
1489 dsl_pool_config_enter(dp, FTAG);
1490 dsl_scan_visit(scn, tx);
1491 dsl_pool_config_exit(dp, FTAG);
1492 (void) zio_wait(scn->scn_zio_root);
1493 scn->scn_zio_root = NULL;
1494
1495 zfs_dbgmsg("visited %llu blocks in %llums",
1496 (longlong_t)scn->scn_visited_this_txg,
1497 (longlong_t)NSEC2MSEC(gethrtime() - scn->scn_sync_start_time));
1498
1499 if (!scn->scn_pausing) {
1500 /* finished with scan. */
1501 zfs_dbgmsg("finished scan txg %llu", (longlong_t)tx->tx_txg);
1502 dsl_scan_done(scn, B_TRUE, tx);
1503 }
1504
1505 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
1506 mutex_enter(&spa->spa_scrub_lock);
1507 while (spa->spa_scrub_inflight > 0) {
1508 cv_wait(&spa->spa_scrub_io_cv,
1509 &spa->spa_scrub_lock);
1510 }
1511 mutex_exit(&spa->spa_scrub_lock);
1512 }
1513
1514 dsl_scan_sync_state(scn, tx);
1515 }
1516
1517 /*
1518 * This will start a new scan, or restart an existing one.
1519 */
1520 void
1521 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
1522 {
1523 if (txg == 0) {
1524 dmu_tx_t *tx;
1525 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1526 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1527
1528 txg = dmu_tx_get_txg(tx);
1529 dp->dp_scan->scn_restart_txg = txg;
1530 dmu_tx_commit(tx);
1531 } else {
1532 dp->dp_scan->scn_restart_txg = txg;
1533 }
1534 zfs_dbgmsg("restarting resilver txg=%llu", txg);
1535 }
1536
1537 boolean_t
1538 dsl_scan_resilvering(dsl_pool_t *dp)
1539 {
1540 return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
1541 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
1542 }
1543
1544 /*
1545 * scrub consumers
1546 */
1547
1548 static void
1549 count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
1550 {
1551 int i;
1552
1553 /*
1554 * If we resume after a reboot, zab will be NULL; don't record
1555 * incomplete stats in that case.
1556 */
1557 if (zab == NULL)
1558 return;
1559
1560 for (i = 0; i < 4; i++) {
1561 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
1562 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
1563 if (t & DMU_OT_NEWTYPE)
1564 t = DMU_OT_OTHER;
1565 zfs_blkstat_t *zb = &zab->zab_type[l][t];
1566 int equal;
1567
1568 zb->zb_count++;
1569 zb->zb_asize += BP_GET_ASIZE(bp);
1570 zb->zb_lsize += BP_GET_LSIZE(bp);
1571 zb->zb_psize += BP_GET_PSIZE(bp);
1572 zb->zb_gangs += BP_COUNT_GANG(bp);
1573
1574 switch (BP_GET_NDVAS(bp)) {
1575 case 2:
1576 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1577 DVA_GET_VDEV(&bp->blk_dva[1]))
1578 zb->zb_ditto_2_of_2_samevdev++;
1579 break;
1580 case 3:
1581 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1582 DVA_GET_VDEV(&bp->blk_dva[1])) +
1583 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1584 DVA_GET_VDEV(&bp->blk_dva[2])) +
1585 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
1586 DVA_GET_VDEV(&bp->blk_dva[2]));
1587 if (equal == 1)
1588 zb->zb_ditto_2_of_3_samevdev++;
1589 else if (equal == 3)
1590 zb->zb_ditto_3_of_3_samevdev++;
1591 break;
1592 }
1593 }
1594 }
1595
1596 static void
1597 dsl_scan_scrub_done(zio_t *zio)
1598 {
1599 spa_t *spa = zio->io_spa;
1600
1601 zio_data_buf_free(zio->io_data, zio->io_size);
1602
1603 mutex_enter(&spa->spa_scrub_lock);
1604 spa->spa_scrub_inflight--;
1605 cv_broadcast(&spa->spa_scrub_io_cv);
1606
1607 if (zio->io_error && (zio->io_error != ECKSUM ||
1608 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
1609 spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
1610 }
1611 mutex_exit(&spa->spa_scrub_lock);
1612 }
1613
1614 static int
1615 dsl_scan_scrub_cb(dsl_pool_t *dp,
1616 const blkptr_t *bp, const zbookmark_t *zb)
1617 {
1618 dsl_scan_t *scn = dp->dp_scan;
1619 size_t size = BP_GET_PSIZE(bp);
1620 spa_t *spa = dp->dp_spa;
1621 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
1622 boolean_t needs_io;
1623 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
1624 int zio_priority;
1625 int scan_delay = 0;
1626
1627 if (phys_birth <= scn->scn_phys.scn_min_txg ||
1628 phys_birth >= scn->scn_phys.scn_max_txg)
1629 return (0);
1630
1631 count_block(dp->dp_blkstats, bp);
1632
1633 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
1634 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
1635 zio_flags |= ZIO_FLAG_SCRUB;
1636 zio_priority = ZIO_PRIORITY_SCRUB;
1637 needs_io = B_TRUE;
1638 scan_delay = zfs_scrub_delay;
1639 } else {
1640 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
1641 zio_flags |= ZIO_FLAG_RESILVER;
1642 zio_priority = ZIO_PRIORITY_RESILVER;
1643 needs_io = B_FALSE;
1644 scan_delay = zfs_resilver_delay;
1645 }
1646
1647 /* If it's an intent log block, failure is expected. */
1648 if (zb->zb_level == ZB_ZIL_LEVEL)
1649 zio_flags |= ZIO_FLAG_SPECULATIVE;
1650
1651 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
1652 vdev_t *vd = vdev_lookup_top(spa,
1653 DVA_GET_VDEV(&bp->blk_dva[d]));
1654
1655 /*
1656 * Keep track of how much data we've examined so that
1657 * zpool(1M) status can make useful progress reports.
1658 */
1659 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
1660 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
1661
1662 /* if it's a resilver, this may not be in the target range */
1663 if (!needs_io) {
1664 if (DVA_GET_GANG(&bp->blk_dva[d])) {
1665 /*
1666 * Gang members may be spread across multiple
1667 * vdevs, so the best estimate we have is the
1668 * scrub range, which has already been checked.
1669 * XXX -- it would be better to change our
1670 * allocation policy to ensure that all
1671 * gang members reside on the same vdev.
1672 */
1673 needs_io = B_TRUE;
1674 } else {
1675 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
1676 phys_birth, 1);
1677 }
1678 }
1679 }
1680
1681 if (needs_io && !zfs_no_scrub_io) {
1682 vdev_t *rvd = spa->spa_root_vdev;
1683 uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
1684 void *data = zio_data_buf_alloc(size);
1685
1686 mutex_enter(&spa->spa_scrub_lock);
1687 while (spa->spa_scrub_inflight >= maxinflight)
1688 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1689 spa->spa_scrub_inflight++;
1690 mutex_exit(&spa->spa_scrub_lock);
1691
1692 /*
1693 * If we're seeing recent (zfs_scan_idle) "important" I/Os
1694 * then throttle our workload to limit the impact of a scan.
1695 */
1696 if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
1697 delay(scan_delay);
1698
1699 zio_nowait(zio_read(NULL, spa, bp, data, size,
1700 dsl_scan_scrub_done, NULL, zio_priority,
1701 zio_flags, zb));
1702 }
1703
1704 /* do not relocate this block */
1705 return (0);
1706 }
1707
1708 int
1709 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
1710 {
1711 spa_t *spa = dp->dp_spa;
1712
1713 /*
1714 * Purge all vdev caches and probe all devices. We do this here
1715 * rather than in sync context because this requires a writer lock
1716 * on the spa_config lock, which we can't do from sync context. The
1717 * spa_scrub_reopen flag indicates that vdev_open() should not
1718 * attempt to start another scrub.
1719 */
1720 spa_vdev_state_enter(spa, SCL_NONE);
1721 spa->spa_scrub_reopen = B_TRUE;
1722 vdev_reopen(spa->spa_root_vdev);
1723 spa->spa_scrub_reopen = B_FALSE;
1724 (void) spa_vdev_state_exit(spa, NULL, 0);
1725
1726 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
1727 dsl_scan_setup_sync, &func, 0));
1728 }