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6251 add tunable to disable free_bpobj processing
[unleashed.git] / usr / src / uts / common / fs / zfs / dsl_scan.c
blob6ba5cb6a1c831f681fba16dbc8d25fd8b59b13c9
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) 2011, 2015 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 *,
54 const zbookmark_phys_t *);
55
56 static scan_cb_t dsl_scan_scrub_cb;
57 static void dsl_scan_cancel_sync(void *, dmu_tx_t *);
58 static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *tx);
59
60 int zfs_top_maxinflight = 32; /* maximum I/Os per top-level */
61 int zfs_resilver_delay = 2; /* number of ticks to delay resilver */
62 int zfs_scrub_delay = 4; /* number of ticks to delay scrub */
63 int zfs_scan_idle = 50; /* idle window in clock ticks */
64
65 int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
66 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
67 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
68 boolean_t zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
69 boolean_t zfs_no_scrub_prefetch = B_FALSE; /* set to disable scrub prefetch */
70 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
71 int dsl_scan_delay_completion = B_FALSE; /* set to delay scan completion */
72 /* max number of blocks to free in a single TXG */
73 uint64_t zfs_free_max_blocks = UINT64_MAX;
74
75 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
76 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
77 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
78
79 extern int zfs_txg_timeout;
80
81 /*
82 * Enable/disable the processing of the free_bpobj object.
83 */
84 boolean_t zfs_free_bpobj_enabled = B_TRUE;
85
86 /* the order has to match pool_scan_type */
87 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
88 NULL,
89 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
90 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
91 };
92
93 int
94 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
95 {
96 int err;
97 dsl_scan_t *scn;
98 spa_t *spa = dp->dp_spa;
99 uint64_t f;
100
101 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
102 scn->scn_dp = dp;
103
104 /*
105 * It's possible that we're resuming a scan after a reboot so
106 * make sure that the scan_async_destroying flag is initialized
107 * appropriately.
108 */
109 ASSERT(!scn->scn_async_destroying);
110 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
111 SPA_FEATURE_ASYNC_DESTROY);
112
113 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
114 "scrub_func", sizeof (uint64_t), 1, &f);
115 if (err == 0) {
116 /*
117 * There was an old-style scrub in progress. Restart a
118 * new-style scrub from the beginning.
119 */
120 scn->scn_restart_txg = txg;
121 zfs_dbgmsg("old-style scrub was in progress; "
122 "restarting new-style scrub in txg %llu",
123 scn->scn_restart_txg);
124
125 /*
126 * Load the queue obj from the old location so that it
127 * can be freed by dsl_scan_done().
128 */
129 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
130 "scrub_queue", sizeof (uint64_t), 1,
131 &scn->scn_phys.scn_queue_obj);
132 } else {
133 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
134 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
135 &scn->scn_phys);
136 if (err == ENOENT)
137 return (0);
138 else if (err)
139 return (err);
140
141 if (scn->scn_phys.scn_state == DSS_SCANNING &&
142 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
143 /*
144 * A new-type scrub was in progress on an old
145 * pool, and the pool was accessed by old
146 * software. Restart from the beginning, since
147 * the old software may have changed the pool in
148 * the meantime.
149 */
150 scn->scn_restart_txg = txg;
151 zfs_dbgmsg("new-style scrub was modified "
152 "by old software; restarting in txg %llu",
153 scn->scn_restart_txg);
154 }
155 }
156
157 spa_scan_stat_init(spa);
158 return (0);
159 }
160
161 void
162 dsl_scan_fini(dsl_pool_t *dp)
163 {
164 if (dp->dp_scan) {
165 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
166 dp->dp_scan = NULL;
167 }
168 }
169
170 /* ARGSUSED */
171 static int
172 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
173 {
174 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
175
176 if (scn->scn_phys.scn_state == DSS_SCANNING)
177 return (SET_ERROR(EBUSY));
178
179 return (0);
180 }
181
182 static void
183 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
184 {
185 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
186 pool_scan_func_t *funcp = arg;
187 dmu_object_type_t ot = 0;
188 dsl_pool_t *dp = scn->scn_dp;
189 spa_t *spa = dp->dp_spa;
190
191 ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
192 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
193 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
194 scn->scn_phys.scn_func = *funcp;
195 scn->scn_phys.scn_state = DSS_SCANNING;
196 scn->scn_phys.scn_min_txg = 0;
197 scn->scn_phys.scn_max_txg = tx->tx_txg;
198 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
199 scn->scn_phys.scn_start_time = gethrestime_sec();
200 scn->scn_phys.scn_errors = 0;
201 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
202 scn->scn_restart_txg = 0;
203 scn->scn_done_txg = 0;
204 spa_scan_stat_init(spa);
205
206 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
207 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
208
209 /* rewrite all disk labels */
210 vdev_config_dirty(spa->spa_root_vdev);
211
212 if (vdev_resilver_needed(spa->spa_root_vdev,
213 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
214 spa_event_notify(spa, NULL, ESC_ZFS_RESILVER_START);
215 } else {
216 spa_event_notify(spa, NULL, ESC_ZFS_SCRUB_START);
217 }
218
219 spa->spa_scrub_started = B_TRUE;
220 /*
221 * If this is an incremental scrub, limit the DDT scrub phase
222 * to just the auto-ditto class (for correctness); the rest
223 * of the scrub should go faster using top-down pruning.
224 */
225 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
226 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
227
228 }
229
230 /* back to the generic stuff */
231
232 if (dp->dp_blkstats == NULL) {
233 dp->dp_blkstats =
234 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
235 }
236 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
237
238 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
239 ot = DMU_OT_ZAP_OTHER;
240
241 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
242 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
243
244 dsl_scan_sync_state(scn, tx);
245
246 spa_history_log_internal(spa, "scan setup", tx,
247 "func=%u mintxg=%llu maxtxg=%llu",
248 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
249 }
250
251 /* ARGSUSED */
252 static void
253 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
254 {
255 static const char *old_names[] = {
256 "scrub_bookmark",
257 "scrub_ddt_bookmark",
258 "scrub_ddt_class_max",
259 "scrub_queue",
260 "scrub_min_txg",
261 "scrub_max_txg",
262 "scrub_func",
263 "scrub_errors",
264 NULL
265 };
266
267 dsl_pool_t *dp = scn->scn_dp;
268 spa_t *spa = dp->dp_spa;
269 int i;
270
271 /* Remove any remnants of an old-style scrub. */
272 for (i = 0; old_names[i]; i++) {
273 (void) zap_remove(dp->dp_meta_objset,
274 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
275 }
276
277 if (scn->scn_phys.scn_queue_obj != 0) {
278 VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
279 scn->scn_phys.scn_queue_obj, tx));
280 scn->scn_phys.scn_queue_obj = 0;
281 }
282
283 /*
284 * If we were "restarted" from a stopped state, don't bother
285 * with anything else.
286 */
287 if (scn->scn_phys.scn_state != DSS_SCANNING)
288 return;
289
290 if (complete)
291 scn->scn_phys.scn_state = DSS_FINISHED;
292 else
293 scn->scn_phys.scn_state = DSS_CANCELED;
294
295 spa_history_log_internal(spa, "scan done", tx,
296 "complete=%u", complete);
297
298 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
299 mutex_enter(&spa->spa_scrub_lock);
300 while (spa->spa_scrub_inflight > 0) {
301 cv_wait(&spa->spa_scrub_io_cv,
302 &spa->spa_scrub_lock);
303 }
304 mutex_exit(&spa->spa_scrub_lock);
305 spa->spa_scrub_started = B_FALSE;
306 spa->spa_scrub_active = B_FALSE;
307
308 /*
309 * If the scrub/resilver completed, update all DTLs to
310 * reflect this. Whether it succeeded or not, vacate
311 * all temporary scrub DTLs.
312 */
313 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
314 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
315 if (complete) {
316 spa_event_notify(spa, NULL, scn->scn_phys.scn_min_txg ?
317 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
318 }
319 spa_errlog_rotate(spa);
320
321 /*
322 * We may have finished replacing a device.
323 * Let the async thread assess this and handle the detach.
324 */
325 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
326 }
327
328 scn->scn_phys.scn_end_time = gethrestime_sec();
329 }
330
331 /* ARGSUSED */
332 static int
333 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
334 {
335 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
336
337 if (scn->scn_phys.scn_state != DSS_SCANNING)
338 return (SET_ERROR(ENOENT));
339 return (0);
340 }
341
342 /* ARGSUSED */
343 static void
344 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
345 {
346 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
347
348 dsl_scan_done(scn, B_FALSE, tx);
349 dsl_scan_sync_state(scn, tx);
350 }
351
352 int
353 dsl_scan_cancel(dsl_pool_t *dp)
354 {
355 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
356 dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED));
357 }
358
359 static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
360 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
361 dmu_objset_type_t ostype, dmu_tx_t *tx);
362 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
363 dmu_objset_type_t ostype,
364 dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
365
366 void
367 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
368 {
369 zio_free(dp->dp_spa, txg, bp);
370 }
371
372 void
373 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
374 {
375 ASSERT(dsl_pool_sync_context(dp));
376 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
377 }
378
379 static uint64_t
380 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
381 {
382 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
383 if (ds->ds_is_snapshot)
384 return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
385 return (smt);
386 }
387
388 static void
389 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
390 {
391 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
392 DMU_POOL_DIRECTORY_OBJECT,
393 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
394 &scn->scn_phys, tx));
395 }
396
397 extern int zfs_vdev_async_write_active_min_dirty_percent;
398
399 static boolean_t
400 dsl_scan_check_pause(dsl_scan_t *scn, const zbookmark_phys_t *zb)
401 {
402 /* we never skip user/group accounting objects */
403 if (zb && (int64_t)zb->zb_object < 0)
404 return (B_FALSE);
405
406 if (scn->scn_pausing)
407 return (B_TRUE); /* we're already pausing */
408
409 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
410 return (B_FALSE); /* we're resuming */
411
412 /* We only know how to resume from level-0 blocks. */
413 if (zb && zb->zb_level != 0)
414 return (B_FALSE);
415
416 /*
417 * We pause if:
418 * - we have scanned for the maximum time: an entire txg
419 * timeout (default 5 sec)
420 * or
421 * - we have scanned for at least the minimum time (default 1 sec
422 * for scrub, 3 sec for resilver), and either we have sufficient
423 * dirty data that we are starting to write more quickly
424 * (default 30%), or someone is explicitly waiting for this txg
425 * to complete.
426 * or
427 * - the spa is shutting down because this pool is being exported
428 * or the machine is rebooting.
429 */
430 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
431 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
432 uint64_t elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
433 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
434 if (elapsed_nanosecs / NANOSEC >= zfs_txg_timeout ||
435 (NSEC2MSEC(elapsed_nanosecs) > mintime &&
436 (txg_sync_waiting(scn->scn_dp) ||
437 dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent)) ||
438 spa_shutting_down(scn->scn_dp->dp_spa)) {
439 if (zb) {
440 dprintf("pausing at bookmark %llx/%llx/%llx/%llx\n",
441 (longlong_t)zb->zb_objset,
442 (longlong_t)zb->zb_object,
443 (longlong_t)zb->zb_level,
444 (longlong_t)zb->zb_blkid);
445 scn->scn_phys.scn_bookmark = *zb;
446 }
447 dprintf("pausing at DDT bookmark %llx/%llx/%llx/%llx\n",
448 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
449 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
450 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
451 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
452 scn->scn_pausing = B_TRUE;
453 return (B_TRUE);
454 }
455 return (B_FALSE);
456 }
457
458 typedef struct zil_scan_arg {
459 dsl_pool_t *zsa_dp;
460 zil_header_t *zsa_zh;
461 } zil_scan_arg_t;
462
463 /* ARGSUSED */
464 static int
465 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
466 {
467 zil_scan_arg_t *zsa = arg;
468 dsl_pool_t *dp = zsa->zsa_dp;
469 dsl_scan_t *scn = dp->dp_scan;
470 zil_header_t *zh = zsa->zsa_zh;
471 zbookmark_phys_t zb;
472
473 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
474 return (0);
475
476 /*
477 * One block ("stubby") can be allocated a long time ago; we
478 * want to visit that one because it has been allocated
479 * (on-disk) even if it hasn't been claimed (even though for
480 * scrub there's nothing to do to it).
481 */
482 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(dp->dp_spa))
483 return (0);
484
485 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
486 ZB_ZIL_OBJECT, ZB_ZIL_LEVEL, bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
487
488 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
489 return (0);
490 }
491
492 /* ARGSUSED */
493 static int
494 dsl_scan_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
495 {
496 if (lrc->lrc_txtype == TX_WRITE) {
497 zil_scan_arg_t *zsa = arg;
498 dsl_pool_t *dp = zsa->zsa_dp;
499 dsl_scan_t *scn = dp->dp_scan;
500 zil_header_t *zh = zsa->zsa_zh;
501 lr_write_t *lr = (lr_write_t *)lrc;
502 blkptr_t *bp = &lr->lr_blkptr;
503 zbookmark_phys_t zb;
504
505 if (BP_IS_HOLE(bp) ||
506 bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
507 return (0);
508
509 /*
510 * birth can be < claim_txg if this record's txg is
511 * already txg sync'ed (but this log block contains
512 * other records that are not synced)
513 */
514 if (claim_txg == 0 || bp->blk_birth < claim_txg)
515 return (0);
516
517 SET_BOOKMARK(&zb, zh->zh_log.blk_cksum.zc_word[ZIL_ZC_OBJSET],
518 lr->lr_foid, ZB_ZIL_LEVEL,
519 lr->lr_offset / BP_GET_LSIZE(bp));
520
521 VERIFY(0 == scan_funcs[scn->scn_phys.scn_func](dp, bp, &zb));
522 }
523 return (0);
524 }
525
526 static void
527 dsl_scan_zil(dsl_pool_t *dp, zil_header_t *zh)
528 {
529 uint64_t claim_txg = zh->zh_claim_txg;
530 zil_scan_arg_t zsa = { dp, zh };
531 zilog_t *zilog;
532
533 /*
534 * We only want to visit blocks that have been claimed but not yet
535 * replayed (or, in read-only mode, blocks that *would* be claimed).
536 */
537 if (claim_txg == 0 && spa_writeable(dp->dp_spa))
538 return;
539
540 zilog = zil_alloc(dp->dp_meta_objset, zh);
541
542 (void) zil_parse(zilog, dsl_scan_zil_block, dsl_scan_zil_record, &zsa,
543 claim_txg);
544
545 zil_free(zilog);
546 }
547
548 /* ARGSUSED */
549 static void
550 dsl_scan_prefetch(dsl_scan_t *scn, arc_buf_t *buf, blkptr_t *bp,
551 uint64_t objset, uint64_t object, uint64_t blkid)
552 {
553 zbookmark_phys_t czb;
554 arc_flags_t flags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
555
556 if (zfs_no_scrub_prefetch)
557 return;
558
559 if (BP_IS_HOLE(bp) || bp->blk_birth <= scn->scn_phys.scn_min_txg ||
560 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE))
561 return;
562
563 SET_BOOKMARK(&czb, objset, object, BP_GET_LEVEL(bp), blkid);
564
565 (void) arc_read(scn->scn_zio_root, scn->scn_dp->dp_spa, bp,
566 NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
567 ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD, &flags, &czb);
568 }
569
570 static boolean_t
571 dsl_scan_check_resume(dsl_scan_t *scn, const dnode_phys_t *dnp,
572 const zbookmark_phys_t *zb)
573 {
574 /*
575 * We never skip over user/group accounting objects (obj<0)
576 */
577 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
578 (int64_t)zb->zb_object >= 0) {
579 /*
580 * If we already visited this bp & everything below (in
581 * a prior txg sync), don't bother doing it again.
582 */
583 if (zbookmark_subtree_completed(dnp, zb,
584 &scn->scn_phys.scn_bookmark))
585 return (B_TRUE);
586
587 /*
588 * If we found the block we're trying to resume from, or
589 * we went past it to a different object, zero it out to
590 * indicate that it's OK to start checking for pausing
591 * again.
592 */
593 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
594 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
595 dprintf("resuming at %llx/%llx/%llx/%llx\n",
596 (longlong_t)zb->zb_objset,
597 (longlong_t)zb->zb_object,
598 (longlong_t)zb->zb_level,
599 (longlong_t)zb->zb_blkid);
600 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
601 }
602 }
603 return (B_FALSE);
604 }
605
606 /*
607 * Return nonzero on i/o error.
608 * Return new buf to write out in *bufp.
609 */
610 static int
611 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
612 dnode_phys_t *dnp, const blkptr_t *bp,
613 const zbookmark_phys_t *zb, dmu_tx_t *tx)
614 {
615 dsl_pool_t *dp = scn->scn_dp;
616 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
617 int err;
618
619 if (BP_GET_LEVEL(bp) > 0) {
620 arc_flags_t flags = ARC_FLAG_WAIT;
621 int i;
622 blkptr_t *cbp;
623 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
624 arc_buf_t *buf;
625
626 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
627 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
628 if (err) {
629 scn->scn_phys.scn_errors++;
630 return (err);
631 }
632 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
633 dsl_scan_prefetch(scn, buf, cbp, zb->zb_objset,
634 zb->zb_object, zb->zb_blkid * epb + i);
635 }
636 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
637 zbookmark_phys_t czb;
638
639 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
640 zb->zb_level - 1,
641 zb->zb_blkid * epb + i);
642 dsl_scan_visitbp(cbp, &czb, dnp,
643 ds, scn, ostype, tx);
644 }
645 (void) arc_buf_remove_ref(buf, &buf);
646 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
647 arc_flags_t flags = ARC_FLAG_WAIT;
648 dnode_phys_t *cdnp;
649 int i, j;
650 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
651 arc_buf_t *buf;
652
653 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
654 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
655 if (err) {
656 scn->scn_phys.scn_errors++;
657 return (err);
658 }
659 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
660 for (j = 0; j < cdnp->dn_nblkptr; j++) {
661 blkptr_t *cbp = &cdnp->dn_blkptr[j];
662 dsl_scan_prefetch(scn, buf, cbp,
663 zb->zb_objset, zb->zb_blkid * epb + i, j);
664 }
665 }
666 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
667 dsl_scan_visitdnode(scn, ds, ostype,
668 cdnp, zb->zb_blkid * epb + i, tx);
669 }
670
671 (void) arc_buf_remove_ref(buf, &buf);
672 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
673 arc_flags_t flags = ARC_FLAG_WAIT;
674 objset_phys_t *osp;
675 arc_buf_t *buf;
676
677 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
678 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
679 if (err) {
680 scn->scn_phys.scn_errors++;
681 return (err);
682 }
683
684 osp = buf->b_data;
685
686 dsl_scan_visitdnode(scn, ds, osp->os_type,
687 &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx);
688
689 if (OBJSET_BUF_HAS_USERUSED(buf)) {
690 /*
691 * We also always visit user/group accounting
692 * objects, and never skip them, even if we are
693 * pausing. This is necessary so that the space
694 * deltas from this txg get integrated.
695 */
696 dsl_scan_visitdnode(scn, ds, osp->os_type,
697 &osp->os_groupused_dnode,
698 DMU_GROUPUSED_OBJECT, tx);
699 dsl_scan_visitdnode(scn, ds, osp->os_type,
700 &osp->os_userused_dnode,
701 DMU_USERUSED_OBJECT, tx);
702 }
703 (void) arc_buf_remove_ref(buf, &buf);
704 }
705
706 return (0);
707 }
708
709 static void
710 dsl_scan_visitdnode(dsl_scan_t *scn, dsl_dataset_t *ds,
711 dmu_objset_type_t ostype, dnode_phys_t *dnp,
712 uint64_t object, dmu_tx_t *tx)
713 {
714 int j;
715
716 for (j = 0; j < dnp->dn_nblkptr; j++) {
717 zbookmark_phys_t czb;
718
719 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
720 dnp->dn_nlevels - 1, j);
721 dsl_scan_visitbp(&dnp->dn_blkptr[j],
722 &czb, dnp, ds, scn, ostype, tx);
723 }
724
725 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
726 zbookmark_phys_t czb;
727 SET_BOOKMARK(&czb, ds ? ds->ds_object : 0, object,
728 0, DMU_SPILL_BLKID);
729 dsl_scan_visitbp(&dnp->dn_spill,
730 &czb, dnp, ds, scn, ostype, tx);
731 }
732 }
733
734 /*
735 * The arguments are in this order because mdb can only print the
736 * first 5; we want them to be useful.
737 */
738 static void
739 dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
740 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
741 dmu_objset_type_t ostype, dmu_tx_t *tx)
742 {
743 dsl_pool_t *dp = scn->scn_dp;
744 arc_buf_t *buf = NULL;
745 blkptr_t bp_toread = *bp;
746
747 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
748
749 if (dsl_scan_check_pause(scn, zb))
750 return;
751
752 if (dsl_scan_check_resume(scn, dnp, zb))
753 return;
754
755 if (BP_IS_HOLE(bp))
756 return;
757
758 scn->scn_visited_this_txg++;
759
760 dprintf_bp(bp,
761 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
762 ds, ds ? ds->ds_object : 0,
763 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
764 bp);
765
766 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
767 return;
768
769 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx) != 0)
770 return;
771
772 /*
773 * If dsl_scan_ddt() has aready visited this block, it will have
774 * already done any translations or scrubbing, so don't call the
775 * callback again.
776 */
777 if (ddt_class_contains(dp->dp_spa,
778 scn->scn_phys.scn_ddt_class_max, bp)) {
779 ASSERT(buf == NULL);
780 return;
781 }
782
783 /*
784 * If this block is from the future (after cur_max_txg), then we
785 * are doing this on behalf of a deleted snapshot, and we will
786 * revisit the future block on the next pass of this dataset.
787 * Don't scan it now unless we need to because something
788 * under it was modified.
789 */
790 if (BP_PHYSICAL_BIRTH(bp) <= scn->scn_phys.scn_cur_max_txg) {
791 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
792 }
793 }
794
795 static void
796 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
797 dmu_tx_t *tx)
798 {
799 zbookmark_phys_t zb;
800
801 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
802 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
803 dsl_scan_visitbp(bp, &zb, NULL,
804 ds, scn, DMU_OST_NONE, tx);
805
806 dprintf_ds(ds, "finished scan%s", "");
807 }
808
809 void
810 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
811 {
812 dsl_pool_t *dp = ds->ds_dir->dd_pool;
813 dsl_scan_t *scn = dp->dp_scan;
814 uint64_t mintxg;
815
816 if (scn->scn_phys.scn_state != DSS_SCANNING)
817 return;
818
819 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
820 if (ds->ds_is_snapshot) {
821 /* Note, scn_cur_{min,max}_txg stays the same. */
822 scn->scn_phys.scn_bookmark.zb_objset =
823 dsl_dataset_phys(ds)->ds_next_snap_obj;
824 zfs_dbgmsg("destroying ds %llu; currently traversing; "
825 "reset zb_objset to %llu",
826 (u_longlong_t)ds->ds_object,
827 (u_longlong_t)dsl_dataset_phys(ds)->
828 ds_next_snap_obj);
829 scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
830 } else {
831 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
832 ZB_DESTROYED_OBJSET, 0, 0, 0);
833 zfs_dbgmsg("destroying ds %llu; currently traversing; "
834 "reset bookmark to -1,0,0,0",
835 (u_longlong_t)ds->ds_object);
836 }
837 } else if (zap_lookup_int_key(dp->dp_meta_objset,
838 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
839 ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
840 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
841 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
842 if (ds->ds_is_snapshot) {
843 /*
844 * We keep the same mintxg; it could be >
845 * ds_creation_txg if the previous snapshot was
846 * deleted too.
847 */
848 VERIFY(zap_add_int_key(dp->dp_meta_objset,
849 scn->scn_phys.scn_queue_obj,
850 dsl_dataset_phys(ds)->ds_next_snap_obj,
851 mintxg, tx) == 0);
852 zfs_dbgmsg("destroying ds %llu; in queue; "
853 "replacing with %llu",
854 (u_longlong_t)ds->ds_object,
855 (u_longlong_t)dsl_dataset_phys(ds)->
856 ds_next_snap_obj);
857 } else {
858 zfs_dbgmsg("destroying ds %llu; in queue; removing",
859 (u_longlong_t)ds->ds_object);
860 }
861 } else {
862 zfs_dbgmsg("destroying ds %llu; ignoring",
863 (u_longlong_t)ds->ds_object);
864 }
865
866 /*
867 * dsl_scan_sync() should be called after this, and should sync
868 * out our changed state, but just to be safe, do it here.
869 */
870 dsl_scan_sync_state(scn, tx);
871 }
872
873 void
874 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
875 {
876 dsl_pool_t *dp = ds->ds_dir->dd_pool;
877 dsl_scan_t *scn = dp->dp_scan;
878 uint64_t mintxg;
879
880 if (scn->scn_phys.scn_state != DSS_SCANNING)
881 return;
882
883 ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
884
885 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
886 scn->scn_phys.scn_bookmark.zb_objset =
887 dsl_dataset_phys(ds)->ds_prev_snap_obj;
888 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
889 "reset zb_objset to %llu",
890 (u_longlong_t)ds->ds_object,
891 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
892 } else if (zap_lookup_int_key(dp->dp_meta_objset,
893 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
894 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
895 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
896 VERIFY(zap_add_int_key(dp->dp_meta_objset,
897 scn->scn_phys.scn_queue_obj,
898 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg, tx) == 0);
899 zfs_dbgmsg("snapshotting ds %llu; in queue; "
900 "replacing with %llu",
901 (u_longlong_t)ds->ds_object,
902 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
903 }
904 dsl_scan_sync_state(scn, tx);
905 }
906
907 void
908 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
909 {
910 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
911 dsl_scan_t *scn = dp->dp_scan;
912 uint64_t mintxg;
913
914 if (scn->scn_phys.scn_state != DSS_SCANNING)
915 return;
916
917 if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
918 scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
919 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
920 "reset zb_objset to %llu",
921 (u_longlong_t)ds1->ds_object,
922 (u_longlong_t)ds2->ds_object);
923 } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
924 scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
925 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
926 "reset zb_objset to %llu",
927 (u_longlong_t)ds2->ds_object,
928 (u_longlong_t)ds1->ds_object);
929 }
930
931 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
932 ds1->ds_object, &mintxg) == 0) {
933 int err;
934
935 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
936 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
937 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
938 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
939 err = zap_add_int_key(dp->dp_meta_objset,
940 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
941 VERIFY(err == 0 || err == EEXIST);
942 if (err == EEXIST) {
943 /* Both were there to begin with */
944 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
945 scn->scn_phys.scn_queue_obj,
946 ds1->ds_object, mintxg, tx));
947 }
948 zfs_dbgmsg("clone_swap ds %llu; in queue; "
949 "replacing with %llu",
950 (u_longlong_t)ds1->ds_object,
951 (u_longlong_t)ds2->ds_object);
952 } else if (zap_lookup_int_key(dp->dp_meta_objset,
953 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
954 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
955 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
956 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
957 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
958 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
959 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
960 zfs_dbgmsg("clone_swap ds %llu; in queue; "
961 "replacing with %llu",
962 (u_longlong_t)ds2->ds_object,
963 (u_longlong_t)ds1->ds_object);
964 }
965
966 dsl_scan_sync_state(scn, tx);
967 }
968
969 struct enqueue_clones_arg {
970 dmu_tx_t *tx;
971 uint64_t originobj;
972 };
973
974 /* ARGSUSED */
975 static int
976 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
977 {
978 struct enqueue_clones_arg *eca = arg;
979 dsl_dataset_t *ds;
980 int err;
981 dsl_scan_t *scn = dp->dp_scan;
982
983 if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != eca->originobj)
984 return (0);
985
986 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
987 if (err)
988 return (err);
989
990 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != eca->originobj) {
991 dsl_dataset_t *prev;
992 err = dsl_dataset_hold_obj(dp,
993 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
994
995 dsl_dataset_rele(ds, FTAG);
996 if (err)
997 return (err);
998 ds = prev;
999 }
1000 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1001 scn->scn_phys.scn_queue_obj, ds->ds_object,
1002 dsl_dataset_phys(ds)->ds_prev_snap_txg, eca->tx) == 0);
1003 dsl_dataset_rele(ds, FTAG);
1004 return (0);
1005 }
1006
1007 static void
1008 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
1009 {
1010 dsl_pool_t *dp = scn->scn_dp;
1011 dsl_dataset_t *ds;
1012 objset_t *os;
1013
1014 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1015
1016 if (dmu_objset_from_ds(ds, &os))
1017 goto out;
1018
1019 /*
1020 * Only the ZIL in the head (non-snapshot) is valid. Even though
1021 * snapshots can have ZIL block pointers (which may be the same
1022 * BP as in the head), they must be ignored. So we traverse the
1023 * ZIL here, rather than in scan_recurse(), because the regular
1024 * snapshot block-sharing rules don't apply to it.
1025 */
1026 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !ds->ds_is_snapshot)
1027 dsl_scan_zil(dp, &os->os_zil_header);
1028
1029 /*
1030 * Iterate over the bps in this ds.
1031 */
1032 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1033 dsl_scan_visit_rootbp(scn, ds, &dsl_dataset_phys(ds)->ds_bp, tx);
1034
1035 char *dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
1036 dsl_dataset_name(ds, dsname);
1037 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1038 "pausing=%u",
1039 (longlong_t)dsobj, dsname,
1040 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1041 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1042 (int)scn->scn_pausing);
1043 kmem_free(dsname, ZFS_MAXNAMELEN);
1044
1045 if (scn->scn_pausing)
1046 goto out;
1047
1048 /*
1049 * We've finished this pass over this dataset.
1050 */
1051
1052 /*
1053 * If we did not completely visit this dataset, do another pass.
1054 */
1055 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1056 zfs_dbgmsg("incomplete pass; visiting again");
1057 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1058 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1059 scn->scn_phys.scn_queue_obj, ds->ds_object,
1060 scn->scn_phys.scn_cur_max_txg, tx) == 0);
1061 goto out;
1062 }
1063
1064 /*
1065 * Add descendent datasets to work queue.
1066 */
1067 if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
1068 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1069 scn->scn_phys.scn_queue_obj,
1070 dsl_dataset_phys(ds)->ds_next_snap_obj,
1071 dsl_dataset_phys(ds)->ds_creation_txg, tx) == 0);
1072 }
1073 if (dsl_dataset_phys(ds)->ds_num_children > 1) {
1074 boolean_t usenext = B_FALSE;
1075 if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
1076 uint64_t count;
1077 /*
1078 * A bug in a previous version of the code could
1079 * cause upgrade_clones_cb() to not set
1080 * ds_next_snap_obj when it should, leading to a
1081 * missing entry. Therefore we can only use the
1082 * next_clones_obj when its count is correct.
1083 */
1084 int err = zap_count(dp->dp_meta_objset,
1085 dsl_dataset_phys(ds)->ds_next_clones_obj, &count);
1086 if (err == 0 &&
1087 count == dsl_dataset_phys(ds)->ds_num_children - 1)
1088 usenext = B_TRUE;
1089 }
1090
1091 if (usenext) {
1092 VERIFY0(zap_join_key(dp->dp_meta_objset,
1093 dsl_dataset_phys(ds)->ds_next_clones_obj,
1094 scn->scn_phys.scn_queue_obj,
1095 dsl_dataset_phys(ds)->ds_creation_txg, tx));
1096 } else {
1097 struct enqueue_clones_arg eca;
1098 eca.tx = tx;
1099 eca.originobj = ds->ds_object;
1100
1101 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1102 enqueue_clones_cb, &eca, DS_FIND_CHILDREN));
1103 }
1104 }
1105
1106 out:
1107 dsl_dataset_rele(ds, FTAG);
1108 }
1109
1110 /* ARGSUSED */
1111 static int
1112 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1113 {
1114 dmu_tx_t *tx = arg;
1115 dsl_dataset_t *ds;
1116 int err;
1117 dsl_scan_t *scn = dp->dp_scan;
1118
1119 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1120 if (err)
1121 return (err);
1122
1123 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1124 dsl_dataset_t *prev;
1125 err = dsl_dataset_hold_obj(dp,
1126 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1127 if (err) {
1128 dsl_dataset_rele(ds, FTAG);
1129 return (err);
1130 }
1131
1132 /*
1133 * If this is a clone, we don't need to worry about it for now.
1134 */
1135 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) {
1136 dsl_dataset_rele(ds, FTAG);
1137 dsl_dataset_rele(prev, FTAG);
1138 return (0);
1139 }
1140 dsl_dataset_rele(ds, FTAG);
1141 ds = prev;
1142 }
1143
1144 VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1145 ds->ds_object, dsl_dataset_phys(ds)->ds_prev_snap_txg, tx) == 0);
1146 dsl_dataset_rele(ds, FTAG);
1147 return (0);
1148 }
1149
1150 /*
1151 * Scrub/dedup interaction.
1152 *
1153 * If there are N references to a deduped block, we don't want to scrub it
1154 * N times -- ideally, we should scrub it exactly once.
1155 *
1156 * We leverage the fact that the dde's replication class (enum ddt_class)
1157 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1158 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1159 *
1160 * To prevent excess scrubbing, the scrub begins by walking the DDT
1161 * to find all blocks with refcnt > 1, and scrubs each of these once.
1162 * Since there are two replication classes which contain blocks with
1163 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1164 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1165 *
1166 * There would be nothing more to say if a block's refcnt couldn't change
1167 * during a scrub, but of course it can so we must account for changes
1168 * in a block's replication class.
1169 *
1170 * Here's an example of what can occur:
1171 *
1172 * If a block has refcnt > 1 during the DDT scrub phase, but has refcnt == 1
1173 * when visited during the top-down scrub phase, it will be scrubbed twice.
1174 * This negates our scrub optimization, but is otherwise harmless.
1175 *
1176 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1177 * on each visit during the top-down scrub phase, it will never be scrubbed.
1178 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1179 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1180 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1181 * while a scrub is in progress, it scrubs the block right then.
1182 */
1183 static void
1184 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1185 {
1186 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1187 ddt_entry_t dde = { 0 };
1188 int error;
1189 uint64_t n = 0;
1190
1191 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1192 ddt_t *ddt;
1193
1194 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1195 break;
1196 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1197 (longlong_t)ddb->ddb_class,
1198 (longlong_t)ddb->ddb_type,
1199 (longlong_t)ddb->ddb_checksum,
1200 (longlong_t)ddb->ddb_cursor);
1201
1202 /* There should be no pending changes to the dedup table */
1203 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1204 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
1205
1206 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1207 n++;
1208
1209 if (dsl_scan_check_pause(scn, NULL))
1210 break;
1211 }
1212
1213 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; pausing=%u",
1214 (longlong_t)n, (int)scn->scn_phys.scn_ddt_class_max,
1215 (int)scn->scn_pausing);
1216
1217 ASSERT(error == 0 || error == ENOENT);
1218 ASSERT(error != ENOENT ||
1219 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1220 }
1221
1222 /* ARGSUSED */
1223 void
1224 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1225 ddt_entry_t *dde, dmu_tx_t *tx)
1226 {
1227 const ddt_key_t *ddk = &dde->dde_key;
1228 ddt_phys_t *ddp = dde->dde_phys;
1229 blkptr_t bp;
1230 zbookmark_phys_t zb = { 0 };
1231
1232 if (scn->scn_phys.scn_state != DSS_SCANNING)
1233 return;
1234
1235 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1236 if (ddp->ddp_phys_birth == 0 ||
1237 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
1238 continue;
1239 ddt_bp_create(checksum, ddk, ddp, &bp);
1240
1241 scn->scn_visited_this_txg++;
1242 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1243 }
1244 }
1245
1246 static void
1247 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1248 {
1249 dsl_pool_t *dp = scn->scn_dp;
1250 zap_cursor_t zc;
1251 zap_attribute_t za;
1252
1253 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1254 scn->scn_phys.scn_ddt_class_max) {
1255 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1256 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1257 dsl_scan_ddt(scn, tx);
1258 if (scn->scn_pausing)
1259 return;
1260 }
1261
1262 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1263 /* First do the MOS & ORIGIN */
1264
1265 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1266 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1267 dsl_scan_visit_rootbp(scn, NULL,
1268 &dp->dp_meta_rootbp, tx);
1269 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1270 if (scn->scn_pausing)
1271 return;
1272
1273 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1274 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1275 enqueue_cb, tx, DS_FIND_CHILDREN));
1276 } else {
1277 dsl_scan_visitds(scn,
1278 dp->dp_origin_snap->ds_object, tx);
1279 }
1280 ASSERT(!scn->scn_pausing);
1281 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
1282 ZB_DESTROYED_OBJSET) {
1283 /*
1284 * If we were paused, continue from here. Note if the
1285 * ds we were paused on was deleted, the zb_objset may
1286 * be -1, so we will skip this and find a new objset
1287 * below.
1288 */
1289 dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
1290 if (scn->scn_pausing)
1291 return;
1292 }
1293
1294 /*
1295 * In case we were paused right at the end of the ds, zero the
1296 * bookmark so we don't think that we're still trying to resume.
1297 */
1298 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_phys_t));
1299
1300 /* keep pulling things out of the zap-object-as-queue */
1301 while (zap_cursor_init(&zc, dp->dp_meta_objset,
1302 scn->scn_phys.scn_queue_obj),
1303 zap_cursor_retrieve(&zc, &za) == 0) {
1304 dsl_dataset_t *ds;
1305 uint64_t dsobj;
1306
1307 dsobj = strtonum(za.za_name, NULL);
1308 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1309 scn->scn_phys.scn_queue_obj, dsobj, tx));
1310
1311 /* Set up min/max txg */
1312 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1313 if (za.za_first_integer != 0) {
1314 scn->scn_phys.scn_cur_min_txg =
1315 MAX(scn->scn_phys.scn_min_txg,
1316 za.za_first_integer);
1317 } else {
1318 scn->scn_phys.scn_cur_min_txg =
1319 MAX(scn->scn_phys.scn_min_txg,
1320 dsl_dataset_phys(ds)->ds_prev_snap_txg);
1321 }
1322 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
1323 dsl_dataset_rele(ds, FTAG);
1324
1325 dsl_scan_visitds(scn, dsobj, tx);
1326 zap_cursor_fini(&zc);
1327 if (scn->scn_pausing)
1328 return;
1329 }
1330 zap_cursor_fini(&zc);
1331 }
1332
1333 static boolean_t
1334 dsl_scan_free_should_pause(dsl_scan_t *scn)
1335 {
1336 uint64_t elapsed_nanosecs;
1337
1338 if (zfs_recover)
1339 return (B_FALSE);
1340
1341 if (scn->scn_visited_this_txg >= zfs_free_max_blocks)
1342 return (B_TRUE);
1343
1344 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
1345 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
1346 (NSEC2MSEC(elapsed_nanosecs) > zfs_free_min_time_ms &&
1347 txg_sync_waiting(scn->scn_dp)) ||
1348 spa_shutting_down(scn->scn_dp->dp_spa));
1349 }
1350
1351 static int
1352 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1353 {
1354 dsl_scan_t *scn = arg;
1355
1356 if (!scn->scn_is_bptree ||
1357 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
1358 if (dsl_scan_free_should_pause(scn))
1359 return (SET_ERROR(ERESTART));
1360 }
1361
1362 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
1363 dmu_tx_get_txg(tx), bp, 0));
1364 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
1365 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
1366 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
1367 scn->scn_visited_this_txg++;
1368 return (0);
1369 }
1370
1371 boolean_t
1372 dsl_scan_active(dsl_scan_t *scn)
1373 {
1374 spa_t *spa = scn->scn_dp->dp_spa;
1375 uint64_t used = 0, comp, uncomp;
1376
1377 if (spa->spa_load_state != SPA_LOAD_NONE)
1378 return (B_FALSE);
1379 if (spa_shutting_down(spa))
1380 return (B_FALSE);
1381 if (scn->scn_phys.scn_state == DSS_SCANNING ||
1382 (scn->scn_async_destroying && !scn->scn_async_stalled))
1383 return (B_TRUE);
1384
1385 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1386 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
1387 &used, &comp, &uncomp);
1388 }
1389 return (used != 0);
1390 }
1391
1392 void
1393 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
1394 {
1395 dsl_scan_t *scn = dp->dp_scan;
1396 spa_t *spa = dp->dp_spa;
1397 int err = 0;
1398
1399 /*
1400 * Check for scn_restart_txg before checking spa_load_state, so
1401 * that we can restart an old-style scan while the pool is being
1402 * imported (see dsl_scan_init).
1403 */
1404 if (scn->scn_restart_txg != 0 &&
1405 scn->scn_restart_txg <= tx->tx_txg) {
1406 pool_scan_func_t func = POOL_SCAN_SCRUB;
1407 dsl_scan_done(scn, B_FALSE, tx);
1408 if (vdev_resilver_needed(spa->spa_root_vdev, NULL, NULL))
1409 func = POOL_SCAN_RESILVER;
1410 zfs_dbgmsg("restarting scan func=%u txg=%llu",
1411 func, tx->tx_txg);
1412 dsl_scan_setup_sync(&func, tx);
1413 }
1414
1415 /*
1416 * If the scan is inactive due to a stalled async destroy, try again.
1417 */
1418 if ((!scn->scn_async_stalled && !dsl_scan_active(scn)) ||
1419 spa_sync_pass(dp->dp_spa) > 1)
1420 return;
1421
1422 scn->scn_visited_this_txg = 0;
1423 scn->scn_pausing = B_FALSE;
1424 scn->scn_sync_start_time = gethrtime();
1425 spa->spa_scrub_active = B_TRUE;
1426
1427 /*
1428 * First process the async destroys. If we pause, don't do
1429 * any scrubbing or resilvering. This ensures that there are no
1430 * async destroys while we are scanning, so the scan code doesn't
1431 * have to worry about traversing it. It is also faster to free the
1432 * blocks than to scrub them.
1433 */
1434 if (zfs_free_bpobj_enabled &&
1435 spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1436 scn->scn_is_bptree = B_FALSE;
1437 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1438 NULL, ZIO_FLAG_MUSTSUCCEED);
1439 err = bpobj_iterate(&dp->dp_free_bpobj,
1440 dsl_scan_free_block_cb, scn, tx);
1441 VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
1442
1443 if (err != 0 && err != ERESTART)
1444 zfs_panic_recover("error %u from bpobj_iterate()", err);
1445 }
1446
1447 if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) {
1448 ASSERT(scn->scn_async_destroying);
1449 scn->scn_is_bptree = B_TRUE;
1450 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1451 NULL, ZIO_FLAG_MUSTSUCCEED);
1452 err = bptree_iterate(dp->dp_meta_objset,
1453 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx);
1454 VERIFY0(zio_wait(scn->scn_zio_root));
1455
1456 if (err == EIO || err == ECKSUM) {
1457 err = 0;
1458 } else if (err != 0 && err != ERESTART) {
1459 zfs_panic_recover("error %u from "
1460 "traverse_dataset_destroyed()", err);
1461 }
1462
1463 if (bptree_is_empty(dp->dp_meta_objset, dp->dp_bptree_obj)) {
1464 /* finished; deactivate async destroy feature */
1465 spa_feature_decr(spa, SPA_FEATURE_ASYNC_DESTROY, tx);
1466 ASSERT(!spa_feature_is_active(spa,
1467 SPA_FEATURE_ASYNC_DESTROY));
1468 VERIFY0(zap_remove(dp->dp_meta_objset,
1469 DMU_POOL_DIRECTORY_OBJECT,
1470 DMU_POOL_BPTREE_OBJ, tx));
1471 VERIFY0(bptree_free(dp->dp_meta_objset,
1472 dp->dp_bptree_obj, tx));
1473 dp->dp_bptree_obj = 0;
1474 scn->scn_async_destroying = B_FALSE;
1475 scn->scn_async_stalled = B_FALSE;
1476 } else {
1477 /*
1478 * If we didn't make progress, mark the async
1479 * destroy as stalled, so that we will not initiate
1480 * a spa_sync() on its behalf. Note that we only
1481 * check this if we are not finished, because if the
1482 * bptree had no blocks for us to visit, we can
1483 * finish without "making progress".
1484 */
1485 scn->scn_async_stalled =
1486 (scn->scn_visited_this_txg == 0);
1487 }
1488 }
1489 if (scn->scn_visited_this_txg) {
1490 zfs_dbgmsg("freed %llu blocks in %llums from "
1491 "free_bpobj/bptree txg %llu; err=%u",
1492 (longlong_t)scn->scn_visited_this_txg,
1493 (longlong_t)
1494 NSEC2MSEC(gethrtime() - scn->scn_sync_start_time),
1495 (longlong_t)tx->tx_txg, err);
1496 scn->scn_visited_this_txg = 0;
1497
1498 /*
1499 * Write out changes to the DDT that may be required as a
1500 * result of the blocks freed. This ensures that the DDT
1501 * is clean when a scrub/resilver runs.
1502 */
1503 ddt_sync(spa, tx->tx_txg);
1504 }
1505 if (err != 0)
1506 return;
1507 if (!scn->scn_async_destroying && zfs_free_leak_on_eio &&
1508 (dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes != 0 ||
1509 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes != 0 ||
1510 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes != 0)) {
1511 /*
1512 * We have finished background destroying, but there is still
1513 * some space left in the dp_free_dir. Transfer this leaked
1514 * space to the dp_leak_dir.
1515 */
1516 if (dp->dp_leak_dir == NULL) {
1517 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
1518 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
1519 LEAK_DIR_NAME, tx);
1520 VERIFY0(dsl_pool_open_special_dir(dp,
1521 LEAK_DIR_NAME, &dp->dp_leak_dir));
1522 rrw_exit(&dp->dp_config_rwlock, FTAG);
1523 }
1524 dsl_dir_diduse_space(dp->dp_leak_dir, DD_USED_HEAD,
1525 dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
1526 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
1527 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
1528 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
1529 -dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
1530 -dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
1531 -dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
1532 }
1533 if (!scn->scn_async_destroying) {
1534 /* finished; verify that space accounting went to zero */
1535 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes);
1536 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes);
1537 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes);
1538 }
1539
1540 if (scn->scn_phys.scn_state != DSS_SCANNING)
1541 return;
1542
1543 if (scn->scn_done_txg == tx->tx_txg) {
1544 ASSERT(!scn->scn_pausing);
1545 /* finished with scan. */
1546 zfs_dbgmsg("txg %llu scan complete", tx->tx_txg);
1547 dsl_scan_done(scn, B_TRUE, tx);
1548 ASSERT3U(spa->spa_scrub_inflight, ==, 0);
1549 dsl_scan_sync_state(scn, tx);
1550 return;
1551 }
1552
1553 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1554 scn->scn_phys.scn_ddt_class_max) {
1555 zfs_dbgmsg("doing scan sync txg %llu; "
1556 "ddt bm=%llu/%llu/%llu/%llx",
1557 (longlong_t)tx->tx_txg,
1558 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1559 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1560 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1561 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1562 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
1563 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
1564 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
1565 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
1566 } else {
1567 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
1568 (longlong_t)tx->tx_txg,
1569 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
1570 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
1571 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
1572 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
1573 }
1574
1575 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1576 NULL, ZIO_FLAG_CANFAIL);
1577 dsl_pool_config_enter(dp, FTAG);
1578 dsl_scan_visit(scn, tx);
1579 dsl_pool_config_exit(dp, FTAG);
1580 (void) zio_wait(scn->scn_zio_root);
1581 scn->scn_zio_root = NULL;
1582
1583 zfs_dbgmsg("visited %llu blocks in %llums",
1584 (longlong_t)scn->scn_visited_this_txg,
1585 (longlong_t)NSEC2MSEC(gethrtime() - scn->scn_sync_start_time));
1586
1587 if (!scn->scn_pausing) {
1588 scn->scn_done_txg = tx->tx_txg + 1;
1589 zfs_dbgmsg("txg %llu traversal complete, waiting till txg %llu",
1590 tx->tx_txg, scn->scn_done_txg);
1591 }
1592
1593 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
1594 mutex_enter(&spa->spa_scrub_lock);
1595 while (spa->spa_scrub_inflight > 0) {
1596 cv_wait(&spa->spa_scrub_io_cv,
1597 &spa->spa_scrub_lock);
1598 }
1599 mutex_exit(&spa->spa_scrub_lock);
1600 }
1601
1602 dsl_scan_sync_state(scn, tx);
1603 }
1604
1605 /*
1606 * This will start a new scan, or restart an existing one.
1607 */
1608 void
1609 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
1610 {
1611 if (txg == 0) {
1612 dmu_tx_t *tx;
1613 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1614 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1615
1616 txg = dmu_tx_get_txg(tx);
1617 dp->dp_scan->scn_restart_txg = txg;
1618 dmu_tx_commit(tx);
1619 } else {
1620 dp->dp_scan->scn_restart_txg = txg;
1621 }
1622 zfs_dbgmsg("restarting resilver txg=%llu", txg);
1623 }
1624
1625 boolean_t
1626 dsl_scan_resilvering(dsl_pool_t *dp)
1627 {
1628 return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
1629 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
1630 }
1631
1632 /*
1633 * scrub consumers
1634 */
1635
1636 static void
1637 count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
1638 {
1639 int i;
1640
1641 /*
1642 * If we resume after a reboot, zab will be NULL; don't record
1643 * incomplete stats in that case.
1644 */
1645 if (zab == NULL)
1646 return;
1647
1648 for (i = 0; i < 4; i++) {
1649 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
1650 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
1651 if (t & DMU_OT_NEWTYPE)
1652 t = DMU_OT_OTHER;
1653 zfs_blkstat_t *zb = &zab->zab_type[l][t];
1654 int equal;
1655
1656 zb->zb_count++;
1657 zb->zb_asize += BP_GET_ASIZE(bp);
1658 zb->zb_lsize += BP_GET_LSIZE(bp);
1659 zb->zb_psize += BP_GET_PSIZE(bp);
1660 zb->zb_gangs += BP_COUNT_GANG(bp);
1661
1662 switch (BP_GET_NDVAS(bp)) {
1663 case 2:
1664 if (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1665 DVA_GET_VDEV(&bp->blk_dva[1]))
1666 zb->zb_ditto_2_of_2_samevdev++;
1667 break;
1668 case 3:
1669 equal = (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1670 DVA_GET_VDEV(&bp->blk_dva[1])) +
1671 (DVA_GET_VDEV(&bp->blk_dva[0]) ==
1672 DVA_GET_VDEV(&bp->blk_dva[2])) +
1673 (DVA_GET_VDEV(&bp->blk_dva[1]) ==
1674 DVA_GET_VDEV(&bp->blk_dva[2]));
1675 if (equal == 1)
1676 zb->zb_ditto_2_of_3_samevdev++;
1677 else if (equal == 3)
1678 zb->zb_ditto_3_of_3_samevdev++;
1679 break;
1680 }
1681 }
1682 }
1683
1684 static void
1685 dsl_scan_scrub_done(zio_t *zio)
1686 {
1687 spa_t *spa = zio->io_spa;
1688
1689 zio_data_buf_free(zio->io_data, zio->io_size);
1690
1691 mutex_enter(&spa->spa_scrub_lock);
1692 spa->spa_scrub_inflight--;
1693 cv_broadcast(&spa->spa_scrub_io_cv);
1694
1695 if (zio->io_error && (zio->io_error != ECKSUM ||
1696 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
1697 spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
1698 }
1699 mutex_exit(&spa->spa_scrub_lock);
1700 }
1701
1702 static int
1703 dsl_scan_scrub_cb(dsl_pool_t *dp,
1704 const blkptr_t *bp, const zbookmark_phys_t *zb)
1705 {
1706 dsl_scan_t *scn = dp->dp_scan;
1707 size_t size = BP_GET_PSIZE(bp);
1708 spa_t *spa = dp->dp_spa;
1709 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
1710 boolean_t needs_io;
1711 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
1712 int scan_delay = 0;
1713
1714 if (phys_birth <= scn->scn_phys.scn_min_txg ||
1715 phys_birth >= scn->scn_phys.scn_max_txg)
1716 return (0);
1717
1718 count_block(dp->dp_blkstats, bp);
1719
1720 if (BP_IS_EMBEDDED(bp))
1721 return (0);
1722
1723 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
1724 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
1725 zio_flags |= ZIO_FLAG_SCRUB;
1726 needs_io = B_TRUE;
1727 scan_delay = zfs_scrub_delay;
1728 } else {
1729 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
1730 zio_flags |= ZIO_FLAG_RESILVER;
1731 needs_io = B_FALSE;
1732 scan_delay = zfs_resilver_delay;
1733 }
1734
1735 /* If it's an intent log block, failure is expected. */
1736 if (zb->zb_level == ZB_ZIL_LEVEL)
1737 zio_flags |= ZIO_FLAG_SPECULATIVE;
1738
1739 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
1740 vdev_t *vd = vdev_lookup_top(spa,
1741 DVA_GET_VDEV(&bp->blk_dva[d]));
1742
1743 /*
1744 * Keep track of how much data we've examined so that
1745 * zpool(1M) status can make useful progress reports.
1746 */
1747 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
1748 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
1749
1750 /* if it's a resilver, this may not be in the target range */
1751 if (!needs_io) {
1752 if (DVA_GET_GANG(&bp->blk_dva[d])) {
1753 /*
1754 * Gang members may be spread across multiple
1755 * vdevs, so the best estimate we have is the
1756 * scrub range, which has already been checked.
1757 * XXX -- it would be better to change our
1758 * allocation policy to ensure that all
1759 * gang members reside on the same vdev.
1760 */
1761 needs_io = B_TRUE;
1762 } else {
1763 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
1764 phys_birth, 1);
1765 }
1766 }
1767 }
1768
1769 if (needs_io && !zfs_no_scrub_io) {
1770 vdev_t *rvd = spa->spa_root_vdev;
1771 uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
1772 void *data = zio_data_buf_alloc(size);
1773
1774 mutex_enter(&spa->spa_scrub_lock);
1775 while (spa->spa_scrub_inflight >= maxinflight)
1776 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1777 spa->spa_scrub_inflight++;
1778 mutex_exit(&spa->spa_scrub_lock);
1779
1780 /*
1781 * If we're seeing recent (zfs_scan_idle) "important" I/Os
1782 * then throttle our workload to limit the impact of a scan.
1783 */
1784 if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
1785 delay(scan_delay);
1786
1787 zio_nowait(zio_read(NULL, spa, bp, data, size,
1788 dsl_scan_scrub_done, NULL, ZIO_PRIORITY_SCRUB,
1789 zio_flags, zb));
1790 }
1791
1792 /* do not relocate this block */
1793 return (0);
1794 }
1795
1796 int
1797 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
1798 {
1799 spa_t *spa = dp->dp_spa;
1800
1801 /*
1802 * Purge all vdev caches and probe all devices. We do this here
1803 * rather than in sync context because this requires a writer lock
1804 * on the spa_config lock, which we can't do from sync context. The
1805 * spa_scrub_reopen flag indicates that vdev_open() should not
1806 * attempt to start another scrub.
1807 */
1808 spa_vdev_state_enter(spa, SCL_NONE);
1809 spa->spa_scrub_reopen = B_TRUE;
1810 vdev_reopen(spa->spa_root_vdev);
1811 spa->spa_scrub_reopen = B_FALSE;
1812 (void) spa_vdev_state_exit(spa, NULL, 0);
1813
1814 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
1815 dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_NONE));
1816 }
Unleashed OS