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 2016 Gary Mills
24 * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
25 * Copyright 2017 Joyent, Inc.
26 * Copyright (c) 2017 Datto Inc.
27 */
28
29 #include <sys/dsl_scan.h>
30 #include <sys/dsl_pool.h>
31 #include <sys/dsl_dataset.h>
32 #include <sys/dsl_prop.h>
33 #include <sys/dsl_dir.h>
34 #include <sys/dsl_synctask.h>
35 #include <sys/dnode.h>
36 #include <sys/dmu_tx.h>
37 #include <sys/dmu_objset.h>
38 #include <sys/arc.h>
39 #include <sys/zap.h>
40 #include <sys/zio.h>
41 #include <sys/zfs_context.h>
42 #include <sys/fs/zfs.h>
43 #include <sys/zfs_znode.h>
44 #include <sys/spa_impl.h>
45 #include <sys/vdev_impl.h>
46 #include <sys/zil_impl.h>
47 #include <sys/zio_checksum.h>
48 #include <sys/ddt.h>
49 #include <sys/sa.h>
50 #include <sys/sa_impl.h>
51 #include <sys/zfeature.h>
52 #include <sys/abd.h>
53 #ifdef _KERNEL
54 #include <sys/zfs_vfsops.h>
55 #endif
56
57 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *,
58 const zbookmark_phys_t *);
59
60 static scan_cb_t dsl_scan_scrub_cb;
61 static void dsl_scan_cancel_sync(void *, dmu_tx_t *);
62 static void dsl_scan_sync_state(dsl_scan_t *, dmu_tx_t *);
63 static boolean_t dsl_scan_restarting(dsl_scan_t *, dmu_tx_t *);
64
65 int zfs_top_maxinflight = 32; /* maximum I/Os per top-level */
66 int zfs_resilver_delay = 2; /* number of ticks to delay resilver */
67 int zfs_scrub_delay = 4; /* number of ticks to delay scrub */
68 int zfs_scan_idle = 50; /* idle window in clock ticks */
69
70 int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
71 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
72 int zfs_obsolete_min_time_ms = 500; /* min millisecs to obsolete per txg */
73 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
74 boolean_t zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
75 boolean_t zfs_no_scrub_prefetch = B_FALSE; /* set to disable scrub prefetch */
76 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
77 int dsl_scan_delay_completion = B_FALSE; /* set to delay scan completion */
78 /* max number of blocks to free in a single TXG */
79 uint64_t zfs_async_block_max_blocks = UINT64_MAX;
80
81 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
82 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
83 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER)
84
85 extern int zfs_txg_timeout;
86
87 /*
88 * Enable/disable the processing of the free_bpobj object.
89 */
90 boolean_t zfs_free_bpobj_enabled = B_TRUE;
91
92 /* the order has to match pool_scan_type */
93 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
94 NULL,
95 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
96 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
97 };
98
99 int
100 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
101 {
102 int err;
103 dsl_scan_t *scn;
104 spa_t *spa = dp->dp_spa;
105 uint64_t f;
106
107 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
108 scn->scn_dp = dp;
109
110 /*
111 * It's possible that we're resuming a scan after a reboot so
112 * make sure that the scan_async_destroying flag is initialized
113 * appropriately.
114 */
115 ASSERT(!scn->scn_async_destroying);
116 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
117 SPA_FEATURE_ASYNC_DESTROY);
118
119 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
120 "scrub_func", sizeof (uint64_t), 1, &f);
121 if (err == 0) {
122 /*
123 * There was an old-style scrub in progress. Restart a
124 * new-style scrub from the beginning.
125 */
126 scn->scn_restart_txg = txg;
127 zfs_dbgmsg("old-style scrub was in progress; "
128 "restarting new-style scrub in txg %llu",
129 scn->scn_restart_txg);
130
131 /*
132 * Load the queue obj from the old location so that it
133 * can be freed by dsl_scan_done().
134 */
135 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
136 "scrub_queue", sizeof (uint64_t), 1,
137 &scn->scn_phys.scn_queue_obj);
138 } else {
139 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
140 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
141 &scn->scn_phys);
142 if (err == ENOENT)
143 return (0);
144 else if (err)
145 return (err);
146
147 if (scn->scn_phys.scn_state == DSS_SCANNING &&
148 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
149 /*
150 * A new-type scrub was in progress on an old
151 * pool, and the pool was accessed by old
152 * software. Restart from the beginning, since
153 * the old software may have changed the pool in
154 * the meantime.
155 */
156 scn->scn_restart_txg = txg;
157 zfs_dbgmsg("new-style scrub was modified "
158 "by old software; restarting in txg %llu",
159 scn->scn_restart_txg);
160 }
161 }
162
163 spa_scan_stat_init(spa);
164 return (0);
165 }
166
167 void
168 dsl_scan_fini(dsl_pool_t *dp)
169 {
170 if (dp->dp_scan) {
171 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
172 dp->dp_scan = NULL;
173 }
174 }
175
176 /* ARGSUSED */
177 static int
178 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
179 {
180 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
181
182 if (scn->scn_phys.scn_state == DSS_SCANNING)
183 return (SET_ERROR(EBUSY));
184
185 return (0);
186 }
187
188 static void
189 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
190 {
191 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
192 pool_scan_func_t *funcp = arg;
193 dmu_object_type_t ot = 0;
194 dsl_pool_t *dp = scn->scn_dp;
195 spa_t *spa = dp->dp_spa;
196
197 ASSERT(scn->scn_phys.scn_state != DSS_SCANNING);
198 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
199 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
200 scn->scn_phys.scn_func = *funcp;
201 scn->scn_phys.scn_state = DSS_SCANNING;
202 scn->scn_phys.scn_min_txg = 0;
203 scn->scn_phys.scn_max_txg = tx->tx_txg;
204 scn->scn_phys.scn_ddt_class_max = DDT_CLASSES - 1; /* the entire DDT */
205 scn->scn_phys.scn_start_time = gethrestime_sec();
206 scn->scn_phys.scn_errors = 0;
207 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
208 scn->scn_restart_txg = 0;
209 scn->scn_done_txg = 0;
210 spa_scan_stat_init(spa);
211
212 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
213 scn->scn_phys.scn_ddt_class_max = zfs_scrub_ddt_class_max;
214
215 /* rewrite all disk labels */
216 vdev_config_dirty(spa->spa_root_vdev);
217
218 if (vdev_resilver_needed(spa->spa_root_vdev,
219 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
220 spa_event_notify(spa, NULL, NULL,
221 ESC_ZFS_RESILVER_START);
222 } else {
223 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_START);
224 }
225
226 spa->spa_scrub_started = B_TRUE;
227 /*
228 * If this is an incremental scrub, limit the DDT scrub phase
229 * to just the auto-ditto class (for correctness); the rest
230 * of the scrub should go faster using top-down pruning.
231 */
232 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
233 scn->scn_phys.scn_ddt_class_max = DDT_CLASS_DITTO;
234
235 }
236
237 /* back to the generic stuff */
238
239 if (dp->dp_blkstats == NULL) {
240 dp->dp_blkstats =
241 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
242 }
243 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
244
245 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
246 ot = DMU_OT_ZAP_OTHER;
247
248 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
249 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
250
251 dsl_scan_sync_state(scn, tx);
252
253 spa_history_log_internal(spa, "scan setup", tx,
254 "func=%u mintxg=%llu maxtxg=%llu",
255 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
256 }
257
258 /* ARGSUSED */
259 static void
260 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
261 {
262 static const char *old_names[] = {
263 "scrub_bookmark",
264 "scrub_ddt_bookmark",
265 "scrub_ddt_class_max",
266 "scrub_queue",
267 "scrub_min_txg",
268 "scrub_max_txg",
269 "scrub_func",
270 "scrub_errors",
271 NULL
272 };
273
274 dsl_pool_t *dp = scn->scn_dp;
275 spa_t *spa = dp->dp_spa;
276 int i;
277
278 /* Remove any remnants of an old-style scrub. */
279 for (i = 0; old_names[i]; i++) {
280 (void) zap_remove(dp->dp_meta_objset,
281 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
282 }
283
284 if (scn->scn_phys.scn_queue_obj != 0) {
285 VERIFY(0 == dmu_object_free(dp->dp_meta_objset,
286 scn->scn_phys.scn_queue_obj, tx));
287 scn->scn_phys.scn_queue_obj = 0;
288 }
289
290 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
291
292 /*
293 * If we were "restarted" from a stopped state, don't bother
294 * with anything else.
295 */
296 if (scn->scn_phys.scn_state != DSS_SCANNING)
297 return;
298
299 if (complete)
300 scn->scn_phys.scn_state = DSS_FINISHED;
301 else
302 scn->scn_phys.scn_state = DSS_CANCELED;
303
304 if (dsl_scan_restarting(scn, tx))
305 spa_history_log_internal(spa, "scan aborted, restarting", tx,
306 "errors=%llu", spa_get_errlog_size(spa));
307 else if (!complete)
308 spa_history_log_internal(spa, "scan cancelled", tx,
309 "errors=%llu", spa_get_errlog_size(spa));
310 else
311 spa_history_log_internal(spa, "scan done", tx,
312 "errors=%llu", spa_get_errlog_size(spa));
313
314 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
315 mutex_enter(&spa->spa_scrub_lock);
316 while (spa->spa_scrub_inflight > 0) {
317 cv_wait(&spa->spa_scrub_io_cv,
318 &spa->spa_scrub_lock);
319 }
320 mutex_exit(&spa->spa_scrub_lock);
321 spa->spa_scrub_started = B_FALSE;
322 spa->spa_scrub_active = B_FALSE;
323
326 * reflect this. Whether it succeeded or not, vacate
327 * all temporary scrub DTLs.
328 */
329 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
330 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
331 if (complete) {
332 spa_event_notify(spa, NULL, NULL,
333 scn->scn_phys.scn_min_txg ?
334 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
335 }
336 spa_errlog_rotate(spa);
337
338 /*
339 * We may have finished replacing a device.
340 * Let the async thread assess this and handle the detach.
341 */
342 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
343 }
344
345 scn->scn_phys.scn_end_time = gethrestime_sec();
346 }
347
348 /* ARGSUSED */
349 static int
350 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
351 {
352 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
353
354 if (scn->scn_phys.scn_state != DSS_SCANNING)
355 return (SET_ERROR(ENOENT));
356 return (0);
357 }
358
359 /* ARGSUSED */
360 static void
361 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
362 {
363 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
364
365 dsl_scan_done(scn, B_FALSE, tx);
366 dsl_scan_sync_state(scn, tx);
367 spa_event_notify(scn->scn_dp->dp_spa, NULL, NULL, ESC_ZFS_SCRUB_ABORT);
368 }
369
370 int
371 dsl_scan_cancel(dsl_pool_t *dp)
372 {
373 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
374 dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED));
375 }
376
377 boolean_t
378 dsl_scan_is_paused_scrub(const dsl_scan_t *scn)
379 {
380 if (dsl_scan_scrubbing(scn->scn_dp) &&
381 scn->scn_phys.scn_flags & DSF_SCRUB_PAUSED)
382 return (B_TRUE);
383
384 return (B_FALSE);
385 }
386
387 static int
401 return (SET_ERROR(EBUSY));
402 } else if (*cmd != POOL_SCRUB_NORMAL) {
403 return (SET_ERROR(ENOTSUP));
404 }
405
406 return (0);
407 }
408
409 static void
410 dsl_scrub_pause_resume_sync(void *arg, dmu_tx_t *tx)
411 {
412 pool_scrub_cmd_t *cmd = arg;
413 dsl_pool_t *dp = dmu_tx_pool(tx);
414 spa_t *spa = dp->dp_spa;
415 dsl_scan_t *scn = dp->dp_scan;
416
417 if (*cmd == POOL_SCRUB_PAUSE) {
418 /* can't pause a scrub when there is no in-progress scrub */
419 spa->spa_scan_pass_scrub_pause = gethrestime_sec();
420 scn->scn_phys.scn_flags |= DSF_SCRUB_PAUSED;
421 dsl_scan_sync_state(scn, tx);
422 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_PAUSED);
423 } else {
424 ASSERT3U(*cmd, ==, POOL_SCRUB_NORMAL);
425 if (dsl_scan_is_paused_scrub(scn)) {
426 /*
427 * We need to keep track of how much time we spend
428 * paused per pass so that we can adjust the scrub rate
429 * shown in the output of 'zpool status'
430 */
431 spa->spa_scan_pass_scrub_spent_paused +=
432 gethrestime_sec() - spa->spa_scan_pass_scrub_pause;
433 spa->spa_scan_pass_scrub_pause = 0;
434 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
435 dsl_scan_sync_state(scn, tx);
436 }
437 }
438 }
439
440 /*
441 * Set scrub pause/resume state if it makes sense to do so
442 */
443 int
444 dsl_scrub_set_pause_resume(const dsl_pool_t *dp, pool_scrub_cmd_t cmd)
445 {
446 return (dsl_sync_task(spa_name(dp->dp_spa),
447 dsl_scrub_pause_resume_check, dsl_scrub_pause_resume_sync, &cmd, 3,
448 ZFS_SPACE_CHECK_RESERVED));
449 }
450
451 boolean_t
452 dsl_scan_scrubbing(const dsl_pool_t *dp)
453 {
454 dsl_scan_t *scn = dp->dp_scan;
455
456 if (scn->scn_phys.scn_state == DSS_SCANNING &&
457 scn->scn_phys.scn_func == POOL_SCAN_SCRUB)
458 return (B_TRUE);
459
460 return (B_FALSE);
461 }
462
463 static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
464 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
465 dmu_objset_type_t ostype, dmu_tx_t *tx);
466 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
467 dmu_objset_type_t ostype,
468 dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
469
470 void
471 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
472 {
473 zio_free(dp->dp_spa, txg, bp);
474 }
475
476 void
477 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
478 {
479 ASSERT(dsl_pool_sync_context(dp));
480 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
481 }
482
483 static uint64_t
484 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
485 {
486 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
487 if (ds->ds_is_snapshot)
488 return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
489 return (smt);
490 }
491
492 static void
493 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx)
494 {
495 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
496 DMU_POOL_DIRECTORY_OBJECT,
497 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
498 &scn->scn_phys, tx));
499 }
500
501 extern int zfs_vdev_async_write_active_min_dirty_percent;
502
503 static boolean_t
504 dsl_scan_check_suspend(dsl_scan_t *scn, const zbookmark_phys_t *zb)
505 {
506 /* we never skip user/group accounting objects */
507 if (zb && (int64_t)zb->zb_object < 0)
508 return (B_FALSE);
509
510 if (scn->scn_suspending)
511 return (B_TRUE); /* we're already suspending */
512
513 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
514 return (B_FALSE); /* we're resuming */
515
516 /* We only know how to resume from level-0 blocks. */
517 if (zb && zb->zb_level != 0)
518 return (B_FALSE);
519
520 /*
521 * We suspend if:
522 * - we have scanned for the maximum time: an entire txg
523 * timeout (default 5 sec)
524 * or
525 * - we have scanned for at least the minimum time (default 1 sec
526 * for scrub, 3 sec for resilver), and either we have sufficient
527 * dirty data that we are starting to write more quickly
528 * (default 30%), or someone is explicitly waiting for this txg
529 * to complete.
530 * or
531 * - the spa is shutting down because this pool is being exported
532 * or the machine is rebooting.
533 */
534 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
535 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
536 uint64_t elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
537 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
538 if (elapsed_nanosecs / NANOSEC >= zfs_txg_timeout ||
539 (NSEC2MSEC(elapsed_nanosecs) > mintime &&
540 (txg_sync_waiting(scn->scn_dp) ||
541 dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent)) ||
542 spa_shutting_down(scn->scn_dp->dp_spa)) {
543 if (zb) {
544 dprintf("suspending at bookmark %llx/%llx/%llx/%llx\n",
545 (longlong_t)zb->zb_objset,
546 (longlong_t)zb->zb_object,
547 (longlong_t)zb->zb_level,
548 (longlong_t)zb->zb_blkid);
549 scn->scn_phys.scn_bookmark = *zb;
550 }
551 dprintf("suspending at DDT bookmark %llx/%llx/%llx/%llx\n",
552 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
553 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
554 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
555 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
556 scn->scn_suspending = B_TRUE;
557 return (B_TRUE);
558 }
559 return (B_FALSE);
560 }
561
562 typedef struct zil_scan_arg {
563 dsl_pool_t *zsa_dp;
564 zil_header_t *zsa_zh;
565 } zil_scan_arg_t;
566
567 /* ARGSUSED */
568 static int
569 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
679 * We never skip over user/group accounting objects (obj<0)
680 */
681 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
682 (int64_t)zb->zb_object >= 0) {
683 /*
684 * If we already visited this bp & everything below (in
685 * a prior txg sync), don't bother doing it again.
686 */
687 if (zbookmark_subtree_completed(dnp, zb,
688 &scn->scn_phys.scn_bookmark))
689 return (B_TRUE);
690
691 /*
692 * If we found the block we're trying to resume from, or
693 * we went past it to a different object, zero it out to
694 * indicate that it's OK to start checking for suspending
695 * again.
696 */
697 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
698 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
699 dprintf("resuming at %llx/%llx/%llx/%llx\n",
700 (longlong_t)zb->zb_objset,
701 (longlong_t)zb->zb_object,
702 (longlong_t)zb->zb_level,
703 (longlong_t)zb->zb_blkid);
704 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
705 }
706 }
707 return (B_FALSE);
708 }
709
710 /*
711 * Return nonzero on i/o error.
712 * Return new buf to write out in *bufp.
713 */
714 static int
715 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
716 dnode_phys_t *dnp, const blkptr_t *bp,
717 const zbookmark_phys_t *zb, dmu_tx_t *tx)
718 {
719 dsl_pool_t *dp = scn->scn_dp;
720 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
721 int err;
722
723 if (BP_GET_LEVEL(bp) > 0) {
724 arc_flags_t flags = ARC_FLAG_WAIT;
725 int i;
726 blkptr_t *cbp;
727 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
728 arc_buf_t *buf;
729
730 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
731 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
732 if (err) {
733 scn->scn_phys.scn_errors++;
734 return (err);
735 }
736 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
737 dsl_scan_prefetch(scn, buf, cbp, zb->zb_objset,
738 zb->zb_object, zb->zb_blkid * epb + i);
739 }
740 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
741 zbookmark_phys_t czb;
742
743 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
744 zb->zb_level - 1,
745 zb->zb_blkid * epb + i);
746 dsl_scan_visitbp(cbp, &czb, dnp,
747 ds, scn, ostype, tx);
748 }
749 arc_buf_destroy(buf, &buf);
750 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
751 arc_flags_t flags = ARC_FLAG_WAIT;
752 dnode_phys_t *cdnp;
753 int i, j;
754 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
755 arc_buf_t *buf;
756
757 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
758 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
759 if (err) {
760 scn->scn_phys.scn_errors++;
761 return (err);
762 }
763 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
764 for (j = 0; j < cdnp->dn_nblkptr; j++) {
765 blkptr_t *cbp = &cdnp->dn_blkptr[j];
766 dsl_scan_prefetch(scn, buf, cbp,
767 zb->zb_objset, zb->zb_blkid * epb + i, j);
768 }
769 }
770 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
771 dsl_scan_visitdnode(scn, ds, ostype,
772 cdnp, zb->zb_blkid * epb + i, tx);
773 }
774
775 arc_buf_destroy(buf, &buf);
776 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
777 arc_flags_t flags = ARC_FLAG_WAIT;
778 objset_phys_t *osp;
779 arc_buf_t *buf;
780
781 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
782 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
783 if (err) {
784 scn->scn_phys.scn_errors++;
785 return (err);
786 }
787
788 osp = buf->b_data;
789
790 dsl_scan_visitdnode(scn, ds, osp->os_type,
791 &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx);
792
793 if (OBJSET_BUF_HAS_USERUSED(buf)) {
794 /*
795 * We also always visit user/group accounting
796 * objects, and never skip them, even if we are
797 * suspending. This is necessary so that the space
798 * deltas from this txg get integrated.
799 */
800 dsl_scan_visitdnode(scn, ds, osp->os_type,
801 &osp->os_groupused_dnode,
802 DMU_GROUPUSED_OBJECT, tx);
803 dsl_scan_visitdnode(scn, ds, osp->os_type,
804 &osp->os_userused_dnode,
844 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
845 dmu_objset_type_t ostype, dmu_tx_t *tx)
846 {
847 dsl_pool_t *dp = scn->scn_dp;
848 arc_buf_t *buf = NULL;
849 blkptr_t bp_toread = *bp;
850
851 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
852
853 if (dsl_scan_check_suspend(scn, zb))
854 return;
855
856 if (dsl_scan_check_resume(scn, dnp, zb))
857 return;
858
859 if (BP_IS_HOLE(bp))
860 return;
861
862 scn->scn_visited_this_txg++;
863
864 dprintf_bp(bp,
865 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
866 ds, ds ? ds->ds_object : 0,
867 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
868 bp);
869
870 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
871 return;
872
873 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx) != 0)
874 return;
875
876 /*
877 * If dsl_scan_ddt() has already visited this block, it will have
878 * already done any translations or scrubbing, so don't call the
879 * callback again.
880 */
881 if (ddt_class_contains(dp->dp_spa,
882 scn->scn_phys.scn_ddt_class_max, bp)) {
883 ASSERT(buf == NULL);
890 * revisit the future block on the next pass of this dataset.
891 * Don't scan it now unless we need to because something
892 * under it was modified.
893 */
894 if (BP_PHYSICAL_BIRTH(bp) <= scn->scn_phys.scn_cur_max_txg) {
895 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
896 }
897 }
898
899 static void
900 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
901 dmu_tx_t *tx)
902 {
903 zbookmark_phys_t zb;
904
905 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
906 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
907 dsl_scan_visitbp(bp, &zb, NULL,
908 ds, scn, DMU_OST_NONE, tx);
909
910 dprintf_ds(ds, "finished scan%s", "");
911 }
912
913 void
914 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
915 {
916 dsl_pool_t *dp = ds->ds_dir->dd_pool;
917 dsl_scan_t *scn = dp->dp_scan;
918 uint64_t mintxg;
919
920 if (scn->scn_phys.scn_state != DSS_SCANNING)
921 return;
922
923 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
924 if (ds->ds_is_snapshot) {
925 /*
926 * Note:
927 * - scn_cur_{min,max}_txg stays the same.
928 * - Setting the flag is not really necessary if
929 * scn_cur_max_txg == scn_max_txg, because there
930 * is nothing after this snapshot that we care
931 * about. However, we set it anyway and then
932 * ignore it when we retraverse it in
933 * dsl_scan_visitds().
934 */
935 scn->scn_phys.scn_bookmark.zb_objset =
936 dsl_dataset_phys(ds)->ds_next_snap_obj;
937 zfs_dbgmsg("destroying ds %llu; currently traversing; "
938 "reset zb_objset to %llu",
939 (u_longlong_t)ds->ds_object,
940 (u_longlong_t)dsl_dataset_phys(ds)->
941 ds_next_snap_obj);
942 scn->scn_phys.scn_flags |= DSF_VISIT_DS_AGAIN;
943 } else {
944 SET_BOOKMARK(&scn->scn_phys.scn_bookmark,
945 ZB_DESTROYED_OBJSET, 0, 0, 0);
946 zfs_dbgmsg("destroying ds %llu; currently traversing; "
947 "reset bookmark to -1,0,0,0",
948 (u_longlong_t)ds->ds_object);
949 }
950 } else if (zap_lookup_int_key(dp->dp_meta_objset,
951 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
952 ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
953 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
954 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
955 if (ds->ds_is_snapshot) {
956 /*
957 * We keep the same mintxg; it could be >
958 * ds_creation_txg if the previous snapshot was
959 * deleted too.
960 */
961 VERIFY(zap_add_int_key(dp->dp_meta_objset,
962 scn->scn_phys.scn_queue_obj,
963 dsl_dataset_phys(ds)->ds_next_snap_obj,
964 mintxg, tx) == 0);
965 zfs_dbgmsg("destroying ds %llu; in queue; "
966 "replacing with %llu",
967 (u_longlong_t)ds->ds_object,
968 (u_longlong_t)dsl_dataset_phys(ds)->
969 ds_next_snap_obj);
970 } else {
971 zfs_dbgmsg("destroying ds %llu; in queue; removing",
972 (u_longlong_t)ds->ds_object);
973 }
974 }
975
976 /*
977 * dsl_scan_sync() should be called after this, and should sync
978 * out our changed state, but just to be safe, do it here.
979 */
980 dsl_scan_sync_state(scn, tx);
981 }
982
983 void
984 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
985 {
986 dsl_pool_t *dp = ds->ds_dir->dd_pool;
987 dsl_scan_t *scn = dp->dp_scan;
988 uint64_t mintxg;
989
990 if (scn->scn_phys.scn_state != DSS_SCANNING)
991 return;
992
993 ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
994
995 if (scn->scn_phys.scn_bookmark.zb_objset == ds->ds_object) {
996 scn->scn_phys.scn_bookmark.zb_objset =
997 dsl_dataset_phys(ds)->ds_prev_snap_obj;
998 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
999 "reset zb_objset to %llu",
1000 (u_longlong_t)ds->ds_object,
1001 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
1002 } else if (zap_lookup_int_key(dp->dp_meta_objset,
1003 scn->scn_phys.scn_queue_obj, ds->ds_object, &mintxg) == 0) {
1004 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1005 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
1006 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1007 scn->scn_phys.scn_queue_obj,
1008 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg, tx) == 0);
1009 zfs_dbgmsg("snapshotting ds %llu; in queue; "
1010 "replacing with %llu",
1011 (u_longlong_t)ds->ds_object,
1012 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
1013 }
1014 dsl_scan_sync_state(scn, tx);
1015 }
1016
1017 void
1018 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
1019 {
1020 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
1021 dsl_scan_t *scn = dp->dp_scan;
1022 uint64_t mintxg;
1023
1024 if (scn->scn_phys.scn_state != DSS_SCANNING)
1025 return;
1026
1027 if (scn->scn_phys.scn_bookmark.zb_objset == ds1->ds_object) {
1028 scn->scn_phys.scn_bookmark.zb_objset = ds2->ds_object;
1029 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
1030 "reset zb_objset to %llu",
1031 (u_longlong_t)ds1->ds_object,
1032 (u_longlong_t)ds2->ds_object);
1033 } else if (scn->scn_phys.scn_bookmark.zb_objset == ds2->ds_object) {
1034 scn->scn_phys.scn_bookmark.zb_objset = ds1->ds_object;
1035 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
1036 "reset zb_objset to %llu",
1037 (u_longlong_t)ds2->ds_object,
1038 (u_longlong_t)ds1->ds_object);
1039 }
1040
1041 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1042 ds1->ds_object, &mintxg) == 0) {
1043 int err;
1044
1045 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
1046 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
1047 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1048 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
1049 err = zap_add_int_key(dp->dp_meta_objset,
1050 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
1051 VERIFY(err == 0 || err == EEXIST);
1052 if (err == EEXIST) {
1053 /* Both were there to begin with */
1054 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
1055 scn->scn_phys.scn_queue_obj,
1056 ds1->ds_object, mintxg, tx));
1057 }
1058 zfs_dbgmsg("clone_swap ds %llu; in queue; "
1059 "replacing with %llu",
1060 (u_longlong_t)ds1->ds_object,
1061 (u_longlong_t)ds2->ds_object);
1062 } else if (zap_lookup_int_key(dp->dp_meta_objset,
1063 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
1064 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
1065 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
1066 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1067 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
1068 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
1069 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
1070 zfs_dbgmsg("clone_swap ds %llu; in queue; "
1071 "replacing with %llu",
1072 (u_longlong_t)ds2->ds_object,
1073 (u_longlong_t)ds1->ds_object);
1074 }
1075
1076 dsl_scan_sync_state(scn, tx);
1077 }
1078
1079 struct enqueue_clones_arg {
1080 dmu_tx_t *tx;
1081 uint64_t originobj;
1082 };
1083
1084 /* ARGSUSED */
1085 static int
1086 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1087 {
1088 struct enqueue_clones_arg *eca = arg;
1089 dsl_dataset_t *ds;
1090 int err;
1091 dsl_scan_t *scn = dp->dp_scan;
1092
1093 if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != eca->originobj)
1094 return (0);
1095
1096 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1097 if (err)
1098 return (err);
1099
1100 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != eca->originobj) {
1101 dsl_dataset_t *prev;
1102 err = dsl_dataset_hold_obj(dp,
1103 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1104
1105 dsl_dataset_rele(ds, FTAG);
1106 if (err)
1107 return (err);
1108 ds = prev;
1109 }
1110 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1111 scn->scn_phys.scn_queue_obj, ds->ds_object,
1112 dsl_dataset_phys(ds)->ds_prev_snap_txg, eca->tx) == 0);
1113 dsl_dataset_rele(ds, FTAG);
1114 return (0);
1115 }
1116
1117 static void
1118 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
1119 {
1120 dsl_pool_t *dp = scn->scn_dp;
1121 dsl_dataset_t *ds;
1122
1123 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1124
1125 if (scn->scn_phys.scn_cur_min_txg >=
1126 scn->scn_phys.scn_max_txg) {
1127 /*
1128 * This can happen if this snapshot was created after the
1129 * scan started, and we already completed a previous snapshot
1130 * that was created after the scan started. This snapshot
1131 * only references blocks with:
1132 *
1133 * birth < our ds_creation_txg
1134 * cur_min_txg is no less than ds_creation_txg.
1135 * We have already visited these blocks.
1136 * or
1137 * birth > scn_max_txg
1138 * The scan requested not to visit these blocks.
1139 *
1140 * Subsequent snapshots (and clones) can reference our
1141 * blocks, or blocks with even higher birth times.
1145 * Note that checking for cur_min_txg >= cur_max_txg
1146 * is not sufficient, because in that case we may need to
1147 * visit subsequent snapshots. This happens when min_txg > 0,
1148 * which raises cur_min_txg. In this case we will visit
1149 * this dataset but skip all of its blocks, because the
1150 * rootbp's birth time is < cur_min_txg. Then we will
1151 * add the next snapshots/clones to the work queue.
1152 */
1153 char *dsname = kmem_alloc(MAXNAMELEN, KM_SLEEP);
1154 dsl_dataset_name(ds, dsname);
1155 zfs_dbgmsg("scanning dataset %llu (%s) is unnecessary because "
1156 "cur_min_txg (%llu) >= max_txg (%llu)",
1157 dsobj, dsname,
1158 scn->scn_phys.scn_cur_min_txg,
1159 scn->scn_phys.scn_max_txg);
1160 kmem_free(dsname, MAXNAMELEN);
1161
1162 goto out;
1163 }
1164
1165 /*
1166 * Only the ZIL in the head (non-snapshot) is valid. Even though
1167 * snapshots can have ZIL block pointers (which may be the same
1168 * BP as in the head), they must be ignored. In addition, $ORIGIN
1169 * doesn't have a objset (i.e. its ds_bp is a hole) so we don't
1170 * need to look for a ZIL in it either. So we traverse the ZIL here,
1171 * rather than in scan_recurse(), because the regular snapshot
1172 * block-sharing rules don't apply to it.
1173 */
1174 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !dsl_dataset_is_snapshot(ds) &&
1175 ds->ds_dir != dp->dp_origin_snap->ds_dir) {
1176 objset_t *os;
1177 if (dmu_objset_from_ds(ds, &os) != 0) {
1178 goto out;
1179 }
1180 dsl_scan_zil(dp, &os->os_zil_header);
1181 }
1182
1183 /*
1184 * Iterate over the bps in this ds.
1185 */
1186 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1187 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1188 dsl_scan_visit_rootbp(scn, ds, &dsl_dataset_phys(ds)->ds_bp, tx);
1189 rrw_exit(&ds->ds_bp_rwlock, FTAG);
1190
1191 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
1192 dsl_dataset_name(ds, dsname);
1193 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1194 "suspending=%u",
1195 (longlong_t)dsobj, dsname,
1196 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1197 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1198 (int)scn->scn_suspending);
1199 kmem_free(dsname, ZFS_MAX_DATASET_NAME_LEN);
1200
1201 if (scn->scn_suspending)
1202 goto out;
1203
1204 /*
1205 * We've finished this pass over this dataset.
1206 */
1207
1208 /*
1209 * If we did not completely visit this dataset, do another pass.
1210 */
1211 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1212 zfs_dbgmsg("incomplete pass; visiting again");
1213 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1214 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1215 scn->scn_phys.scn_queue_obj, ds->ds_object,
1216 scn->scn_phys.scn_cur_max_txg, tx) == 0);
1217 goto out;
1218 }
1219
1220 /*
1221 * Add descendent datasets to work queue.
1222 */
1223 if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
1224 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1225 scn->scn_phys.scn_queue_obj,
1226 dsl_dataset_phys(ds)->ds_next_snap_obj,
1227 dsl_dataset_phys(ds)->ds_creation_txg, tx) == 0);
1228 }
1229 if (dsl_dataset_phys(ds)->ds_num_children > 1) {
1230 boolean_t usenext = B_FALSE;
1231 if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
1232 uint64_t count;
1233 /*
1234 * A bug in a previous version of the code could
1235 * cause upgrade_clones_cb() to not set
1236 * ds_next_snap_obj when it should, leading to a
1237 * missing entry. Therefore we can only use the
1238 * next_clones_obj when its count is correct.
1239 */
1240 int err = zap_count(dp->dp_meta_objset,
1241 dsl_dataset_phys(ds)->ds_next_clones_obj, &count);
1242 if (err == 0 &&
1243 count == dsl_dataset_phys(ds)->ds_num_children - 1)
1244 usenext = B_TRUE;
1245 }
1246
1247 if (usenext) {
1248 VERIFY0(zap_join_key(dp->dp_meta_objset,
1249 dsl_dataset_phys(ds)->ds_next_clones_obj,
1250 scn->scn_phys.scn_queue_obj,
1251 dsl_dataset_phys(ds)->ds_creation_txg, tx));
1252 } else {
1253 struct enqueue_clones_arg eca;
1254 eca.tx = tx;
1255 eca.originobj = ds->ds_object;
1256
1257 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1258 enqueue_clones_cb, &eca, DS_FIND_CHILDREN));
1259 }
1260 }
1261
1262 out:
1263 dsl_dataset_rele(ds, FTAG);
1264 }
1265
1266 /* ARGSUSED */
1267 static int
1268 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1269 {
1270 dmu_tx_t *tx = arg;
1271 dsl_dataset_t *ds;
1272 int err;
1273 dsl_scan_t *scn = dp->dp_scan;
1274
1275 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1276 if (err)
1277 return (err);
1278
1279 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1280 dsl_dataset_t *prev;
1281 err = dsl_dataset_hold_obj(dp,
1282 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1283 if (err) {
1284 dsl_dataset_rele(ds, FTAG);
1285 return (err);
1286 }
1287
1288 /*
1289 * If this is a clone, we don't need to worry about it for now.
1290 */
1291 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) {
1292 dsl_dataset_rele(ds, FTAG);
1293 dsl_dataset_rele(prev, FTAG);
1294 return (0);
1295 }
1296 dsl_dataset_rele(ds, FTAG);
1297 ds = prev;
1298 }
1299
1300 VERIFY(zap_add_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1301 ds->ds_object, dsl_dataset_phys(ds)->ds_prev_snap_txg, tx) == 0);
1302 dsl_dataset_rele(ds, FTAG);
1303 return (0);
1304 }
1305
1306 /*
1307 * Scrub/dedup interaction.
1308 *
1309 * If there are N references to a deduped block, we don't want to scrub it
1310 * N times -- ideally, we should scrub it exactly once.
1311 *
1312 * We leverage the fact that the dde's replication class (enum ddt_class)
1313 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1314 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1315 *
1316 * To prevent excess scrubbing, the scrub begins by walking the DDT
1317 * to find all blocks with refcnt > 1, and scrubs each of these once.
1318 * Since there are two replication classes which contain blocks with
1319 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1320 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1321 *
1332 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1333 * on each visit during the top-down scrub phase, it will never be scrubbed.
1334 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1335 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1336 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1337 * while a scrub is in progress, it scrubs the block right then.
1338 */
1339 static void
1340 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1341 {
1342 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1343 ddt_entry_t dde = { 0 };
1344 int error;
1345 uint64_t n = 0;
1346
1347 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1348 ddt_t *ddt;
1349
1350 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1351 break;
1352 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1353 (longlong_t)ddb->ddb_class,
1354 (longlong_t)ddb->ddb_type,
1355 (longlong_t)ddb->ddb_checksum,
1356 (longlong_t)ddb->ddb_cursor);
1357
1358 /* There should be no pending changes to the dedup table */
1359 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1360 ASSERT(avl_first(&ddt->ddt_tree) == NULL);
1361
1362 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1363 n++;
1364
1365 if (dsl_scan_check_suspend(scn, NULL))
1366 break;
1367 }
1368
1369 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; "
1370 "suspending=%u", (longlong_t)n,
1371 (int)scn->scn_phys.scn_ddt_class_max, (int)scn->scn_suspending);
1372
1373 ASSERT(error == 0 || error == ENOENT);
1374 ASSERT(error != ENOENT ||
1375 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1376 }
1377
1378 /* ARGSUSED */
1379 void
1380 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1381 ddt_entry_t *dde, dmu_tx_t *tx)
1382 {
1383 const ddt_key_t *ddk = &dde->dde_key;
1384 ddt_phys_t *ddp = dde->dde_phys;
1385 blkptr_t bp;
1386 zbookmark_phys_t zb = { 0 };
1387
1388 if (scn->scn_phys.scn_state != DSS_SCANNING)
1389 return;
1390
1391 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1392 if (ddp->ddp_phys_birth == 0 ||
1393 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
1394 continue;
1395 ddt_bp_create(checksum, ddk, ddp, &bp);
1396
1397 scn->scn_visited_this_txg++;
1398 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1399 }
1400 }
1401
1402 static void
1403 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1404 {
1405 dsl_pool_t *dp = scn->scn_dp;
1406 zap_cursor_t zc;
1407 zap_attribute_t za;
1408
1409 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1410 scn->scn_phys.scn_ddt_class_max) {
1411 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1412 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1413 dsl_scan_ddt(scn, tx);
1414 if (scn->scn_suspending)
1415 return;
1416 }
1417
1418 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1419 /* First do the MOS & ORIGIN */
1420
1421 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1422 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1423 dsl_scan_visit_rootbp(scn, NULL,
1424 &dp->dp_meta_rootbp, tx);
1425 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1426 if (scn->scn_suspending)
1427 return;
1428
1429 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1430 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1431 enqueue_cb, tx, DS_FIND_CHILDREN));
1432 } else {
1433 dsl_scan_visitds(scn,
1434 dp->dp_origin_snap->ds_object, tx);
1435 }
1436 ASSERT(!scn->scn_suspending);
1437 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
1438 ZB_DESTROYED_OBJSET) {
1439 /*
1440 * If we were suspended, continue from here. Note if the
1441 * ds we were suspended on was deleted, the zb_objset may
1442 * be -1, so we will skip this and find a new objset
1443 * below.
1444 */
1445 dsl_scan_visitds(scn, scn->scn_phys.scn_bookmark.zb_objset, tx);
1446 if (scn->scn_suspending)
1447 return;
1448 }
1449
1450 /*
1451 * In case we were suspended right at the end of the ds, zero the
1452 * bookmark so we don't think that we're still trying to resume.
1453 */
1454 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_phys_t));
1455
1456 /* keep pulling things out of the zap-object-as-queue */
1457 while (zap_cursor_init(&zc, dp->dp_meta_objset,
1458 scn->scn_phys.scn_queue_obj),
1459 zap_cursor_retrieve(&zc, &za) == 0) {
1460 dsl_dataset_t *ds;
1461 uint64_t dsobj;
1462
1463 dsobj = zfs_strtonum(za.za_name, NULL);
1464 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1465 scn->scn_phys.scn_queue_obj, dsobj, tx));
1466
1467 /* Set up min/max txg */
1468 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1469 if (za.za_first_integer != 0) {
1470 scn->scn_phys.scn_cur_min_txg =
1471 MAX(scn->scn_phys.scn_min_txg,
1472 za.za_first_integer);
1473 } else {
1474 scn->scn_phys.scn_cur_min_txg =
1475 MAX(scn->scn_phys.scn_min_txg,
1476 dsl_dataset_phys(ds)->ds_prev_snap_txg);
1477 }
1478 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
1479 dsl_dataset_rele(ds, FTAG);
1480
1481 dsl_scan_visitds(scn, dsobj, tx);
1482 zap_cursor_fini(&zc);
1483 if (scn->scn_suspending)
1484 return;
1485 }
1486 zap_cursor_fini(&zc);
1487 }
1488
1489 static boolean_t
1490 dsl_scan_async_block_should_pause(dsl_scan_t *scn)
1491 {
1492 uint64_t elapsed_nanosecs;
1493
1494 if (zfs_recover)
1495 return (B_FALSE);
1496
1497 if (scn->scn_visited_this_txg >= zfs_async_block_max_blocks)
1498 return (B_TRUE);
1499
1500 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
1501 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
1502 (NSEC2MSEC(elapsed_nanosecs) > scn->scn_async_block_min_time_ms &&
1503 txg_sync_waiting(scn->scn_dp)) ||
1504 spa_shutting_down(scn->scn_dp->dp_spa));
1505 }
1506
1507 static int
1508 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1509 {
1510 dsl_scan_t *scn = arg;
1511
1512 if (!scn->scn_is_bptree ||
1513 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
1514 if (dsl_scan_async_block_should_pause(scn))
1515 return (SET_ERROR(ERESTART));
1516 }
1517
1518 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
1519 dmu_tx_get_txg(tx), bp, 0));
1520 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
1521 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
1522 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
1523 scn->scn_visited_this_txg++;
1524 return (0);
1525 }
1526
1527 static int
1528 dsl_scan_obsolete_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
1529 {
1530 dsl_scan_t *scn = arg;
1531 const dva_t *dva = &bp->blk_dva[0];
1532
1533 if (dsl_scan_async_block_should_pause(scn))
1534 return (SET_ERROR(ERESTART));
1535
1536 spa_vdev_indirect_mark_obsolete(scn->scn_dp->dp_spa,
1537 DVA_GET_VDEV(dva), DVA_GET_OFFSET(dva),
1538 DVA_GET_ASIZE(dva), tx);
1539 scn->scn_visited_this_txg++;
1540 return (0);
1541 }
1542
1543 boolean_t
1544 dsl_scan_active(dsl_scan_t *scn)
1545 {
1546 spa_t *spa = scn->scn_dp->dp_spa;
1547 uint64_t used = 0, comp, uncomp;
1548
1549 if (spa->spa_load_state != SPA_LOAD_NONE)
1550 return (B_FALSE);
1551 if (spa_shutting_down(spa))
1552 return (B_FALSE);
1553 if ((scn->scn_phys.scn_state == DSS_SCANNING &&
1554 !dsl_scan_is_paused_scrub(scn)) ||
1555 (scn->scn_async_destroying && !scn->scn_async_stalled))
1556 return (B_TRUE);
1557
1558 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1559 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
1560 &used, &comp, &uncomp);
1561 }
1562 return (used != 0);
1563 }
1564
1565 /* Called whenever a txg syncs. */
1566 void
1567 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
1568 {
1569 dsl_scan_t *scn = dp->dp_scan;
1570 spa_t *spa = dp->dp_spa;
1571 int err = 0;
1572
1573 /*
1574 * Check for scn_restart_txg before checking spa_load_state, so
1603 * If the scan is inactive due to a stalled async destroy, try again.
1604 */
1605 if (!scn->scn_async_stalled && !dsl_scan_active(scn))
1606 return;
1607
1608 scn->scn_visited_this_txg = 0;
1609 scn->scn_suspending = B_FALSE;
1610 scn->scn_sync_start_time = gethrtime();
1611 spa->spa_scrub_active = B_TRUE;
1612
1613 /*
1614 * First process the async destroys. If we suspend, don't do
1615 * any scrubbing or resilvering. This ensures that there are no
1616 * async destroys while we are scanning, so the scan code doesn't
1617 * have to worry about traversing it. It is also faster to free the
1618 * blocks than to scrub them.
1619 */
1620 if (zfs_free_bpobj_enabled &&
1621 spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
1622 scn->scn_is_bptree = B_FALSE;
1623 scn->scn_async_block_min_time_ms = zfs_free_min_time_ms;
1624 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1625 NULL, ZIO_FLAG_MUSTSUCCEED);
1626 err = bpobj_iterate(&dp->dp_free_bpobj,
1627 dsl_scan_free_block_cb, scn, tx);
1628 VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
1629
1630 if (err != 0 && err != ERESTART)
1631 zfs_panic_recover("error %u from bpobj_iterate()", err);
1632 }
1633
1634 if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) {
1635 ASSERT(scn->scn_async_destroying);
1636 scn->scn_is_bptree = B_TRUE;
1637 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1638 NULL, ZIO_FLAG_MUSTSUCCEED);
1639 err = bptree_iterate(dp->dp_meta_objset,
1640 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx);
1641 VERIFY0(zio_wait(scn->scn_zio_root));
1642
1643 if (err == EIO || err == ECKSUM) {
1701 * some space left in the dp_free_dir. Transfer this leaked
1702 * space to the dp_leak_dir.
1703 */
1704 if (dp->dp_leak_dir == NULL) {
1705 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
1706 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
1707 LEAK_DIR_NAME, tx);
1708 VERIFY0(dsl_pool_open_special_dir(dp,
1709 LEAK_DIR_NAME, &dp->dp_leak_dir));
1710 rrw_exit(&dp->dp_config_rwlock, FTAG);
1711 }
1712 dsl_dir_diduse_space(dp->dp_leak_dir, DD_USED_HEAD,
1713 dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
1714 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
1715 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
1716 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
1717 -dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
1718 -dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
1719 -dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
1720 }
1721
1722 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying) {
1723 /* finished; verify that space accounting went to zero */
1724 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes);
1725 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes);
1726 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes);
1727 }
1728
1729 EQUIV(bpobj_is_open(&dp->dp_obsolete_bpobj),
1730 0 == zap_contains(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1731 DMU_POOL_OBSOLETE_BPOBJ));
1732 if (err == 0 && bpobj_is_open(&dp->dp_obsolete_bpobj)) {
1733 ASSERT(spa_feature_is_active(dp->dp_spa,
1734 SPA_FEATURE_OBSOLETE_COUNTS));
1735
1736 scn->scn_is_bptree = B_FALSE;
1737 scn->scn_async_block_min_time_ms = zfs_obsolete_min_time_ms;
1738 err = bpobj_iterate(&dp->dp_obsolete_bpobj,
1739 dsl_scan_obsolete_block_cb, scn, tx);
1740 if (err != 0 && err != ERESTART)
1741 zfs_panic_recover("error %u from bpobj_iterate()", err);
1742
1743 if (bpobj_is_empty(&dp->dp_obsolete_bpobj))
1744 dsl_pool_destroy_obsolete_bpobj(dp, tx);
1745 }
1746
1747 if (scn->scn_phys.scn_state != DSS_SCANNING)
1748 return;
1749
1750 if (scn->scn_done_txg == tx->tx_txg) {
1751 ASSERT(!scn->scn_suspending);
1752 /* finished with scan. */
1753 zfs_dbgmsg("txg %llu scan complete", tx->tx_txg);
1754 dsl_scan_done(scn, B_TRUE, tx);
1755 ASSERT3U(spa->spa_scrub_inflight, ==, 0);
1756 dsl_scan_sync_state(scn, tx);
1757 return;
1758 }
1759
1760 if (dsl_scan_is_paused_scrub(scn))
1761 return;
1762
1763 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1764 scn->scn_phys.scn_ddt_class_max) {
1765 zfs_dbgmsg("doing scan sync txg %llu; "
1766 "ddt bm=%llu/%llu/%llu/%llx",
1767 (longlong_t)tx->tx_txg,
1768 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1769 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1770 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1771 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1772 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
1773 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
1774 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
1775 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
1776 } else {
1777 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
1778 (longlong_t)tx->tx_txg,
1779 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
1780 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
1781 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
1782 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
1783 }
1784
1785 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
1786 NULL, ZIO_FLAG_CANFAIL);
1787 dsl_pool_config_enter(dp, FTAG);
1788 dsl_scan_visit(scn, tx);
1789 dsl_pool_config_exit(dp, FTAG);
1790 (void) zio_wait(scn->scn_zio_root);
1791 scn->scn_zio_root = NULL;
1792
1793 zfs_dbgmsg("visited %llu blocks in %llums",
1794 (longlong_t)scn->scn_visited_this_txg,
1795 (longlong_t)NSEC2MSEC(gethrtime() - scn->scn_sync_start_time));
1796
1797 if (!scn->scn_suspending) {
1798 scn->scn_done_txg = tx->tx_txg + 1;
1799 zfs_dbgmsg("txg %llu traversal complete, waiting till txg %llu",
1800 tx->tx_txg, scn->scn_done_txg);
1801 }
1802
1803 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
1804 mutex_enter(&spa->spa_scrub_lock);
1805 while (spa->spa_scrub_inflight > 0) {
1806 cv_wait(&spa->spa_scrub_io_cv,
1807 &spa->spa_scrub_lock);
1808 }
1809 mutex_exit(&spa->spa_scrub_lock);
1810 }
1811
1812 dsl_scan_sync_state(scn, tx);
1813 }
1814
1815 /*
1816 * This will start a new scan, or restart an existing one.
1817 */
1818 void
1819 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
1820 {
1821 if (txg == 0) {
1822 dmu_tx_t *tx;
1823 tx = dmu_tx_create_dd(dp->dp_mos_dir);
1824 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
1825
1826 txg = dmu_tx_get_txg(tx);
1827 dp->dp_scan->scn_restart_txg = txg;
1828 dmu_tx_commit(tx);
1829 } else {
1830 dp->dp_scan->scn_restart_txg = txg;
1831 }
1832 zfs_dbgmsg("restarting resilver txg=%llu", txg);
1833 }
1834
1835 boolean_t
1836 dsl_scan_resilvering(dsl_pool_t *dp)
1837 {
1838 return (dp->dp_scan->scn_phys.scn_state == DSS_SCANNING &&
1839 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
1840 }
1841
1842 /*
1843 * scrub consumers
1844 */
1845
1846 static void
1847 count_block(zfs_all_blkstats_t *zab, const blkptr_t *bp)
1848 {
1849 int i;
1850
1851 /*
1852 * If we resume after a reboot, zab will be NULL; don't record
1853 * incomplete stats in that case.
1854 */
1855 if (zab == NULL)
1856 return;
1857
1858 for (i = 0; i < 4; i++) {
1859 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
1860 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
1861 if (t & DMU_OT_NEWTYPE)
1862 t = DMU_OT_OTHER;
1863 zfs_blkstat_t *zb = &zab->zab_type[l][t];
1864 int equal;
1865
1866 zb->zb_count++;
1867 zb->zb_asize += BP_GET_ASIZE(bp);
1868 zb->zb_lsize += BP_GET_LSIZE(bp);
1869 zb->zb_psize += BP_GET_PSIZE(bp);
1870 zb->zb_gangs += BP_COUNT_GANG(bp);
1884 DVA_GET_VDEV(&bp->blk_dva[2]));
1885 if (equal == 1)
1886 zb->zb_ditto_2_of_3_samevdev++;
1887 else if (equal == 3)
1888 zb->zb_ditto_3_of_3_samevdev++;
1889 break;
1890 }
1891 }
1892 }
1893
1894 static void
1895 dsl_scan_scrub_done(zio_t *zio)
1896 {
1897 spa_t *spa = zio->io_spa;
1898
1899 abd_free(zio->io_abd);
1900
1901 mutex_enter(&spa->spa_scrub_lock);
1902 spa->spa_scrub_inflight--;
1903 cv_broadcast(&spa->spa_scrub_io_cv);
1904
1905 if (zio->io_error && (zio->io_error != ECKSUM ||
1906 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
1907 spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors++;
1908 }
1909 mutex_exit(&spa->spa_scrub_lock);
1910 }
1911
1912 static int
1913 dsl_scan_scrub_cb(dsl_pool_t *dp,
1914 const blkptr_t *bp, const zbookmark_phys_t *zb)
1915 {
1916 dsl_scan_t *scn = dp->dp_scan;
1917 size_t size = BP_GET_PSIZE(bp);
1918 spa_t *spa = dp->dp_spa;
1919 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
1920 boolean_t needs_io;
1921 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
1922 int scan_delay = 0;
1923
1924 if (phys_birth <= scn->scn_phys.scn_min_txg ||
1925 phys_birth >= scn->scn_phys.scn_max_txg)
1926 return (0);
1927
1928 count_block(dp->dp_blkstats, bp);
1929
1930 if (BP_IS_EMBEDDED(bp))
1931 return (0);
1932
1933 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
1934 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB) {
1935 zio_flags |= ZIO_FLAG_SCRUB;
1936 needs_io = B_TRUE;
1937 scan_delay = zfs_scrub_delay;
1938 } else {
1939 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
1940 zio_flags |= ZIO_FLAG_RESILVER;
1941 needs_io = B_FALSE;
1942 scan_delay = zfs_resilver_delay;
1943 }
1944
1945 /* If it's an intent log block, failure is expected. */
1946 if (zb->zb_level == ZB_ZIL_LEVEL)
1947 zio_flags |= ZIO_FLAG_SPECULATIVE;
1948
1949 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
1950 vdev_t *vd = vdev_lookup_top(spa,
1951 DVA_GET_VDEV(&bp->blk_dva[d]));
1952
1953 /*
1954 * Keep track of how much data we've examined so that
1955 * zpool(1M) status can make useful progress reports.
1956 */
1957 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
1958 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
1959
1960 /* if it's a resilver, this may not be in the target range */
1961 if (!needs_io) {
1962 if (DVA_GET_GANG(&bp->blk_dva[d])) {
1963 /*
1964 * Gang members may be spread across multiple
1965 * vdevs, so the best estimate we have is the
1966 * scrub range, which has already been checked.
1967 * XXX -- it would be better to change our
1968 * allocation policy to ensure that all
1969 * gang members reside on the same vdev.
1970 */
1971 needs_io = B_TRUE;
1972 } else {
1973 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
1974 phys_birth, 1);
1975 }
1976 }
1977 }
1978
1979 if (needs_io && !zfs_no_scrub_io) {
1980 vdev_t *rvd = spa->spa_root_vdev;
1981 uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
1982
1983 mutex_enter(&spa->spa_scrub_lock);
1984 while (spa->spa_scrub_inflight >= maxinflight)
1985 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
1986 spa->spa_scrub_inflight++;
1987 mutex_exit(&spa->spa_scrub_lock);
1988
1989 /*
1990 * If we're seeing recent (zfs_scan_idle) "important" I/Os
1991 * then throttle our workload to limit the impact of a scan.
1992 */
1993 if (ddi_get_lbolt64() - spa->spa_last_io <= zfs_scan_idle)
1994 delay(scan_delay);
1995
1996 zio_nowait(zio_read(NULL, spa, bp,
1997 abd_alloc_for_io(size, B_FALSE), size, dsl_scan_scrub_done,
1998 NULL, ZIO_PRIORITY_SCRUB, zio_flags, zb));
1999 }
2000
2001 /* do not relocate this block */
2002 return (0);
2003 }
2004
2005 /*
2006 * Called by the ZFS_IOC_POOL_SCAN ioctl to start a scrub or resilver.
2007 * Can also be called to resume a paused scrub.
2008 */
2009 int
2010 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
2011 {
2012 spa_t *spa = dp->dp_spa;
2013 dsl_scan_t *scn = dp->dp_scan;
2014
2015 /*
2016 * Purge all vdev caches and probe all devices. We do this here
2017 * rather than in sync context because this requires a writer lock
2018 * on the spa_config lock, which we can't do from sync context. The
2019 * spa_scrub_reopen flag indicates that vdev_open() should not
2020 * attempt to start another scrub.
2021 */
2022 spa_vdev_state_enter(spa, SCL_NONE);
2023 spa->spa_scrub_reopen = B_TRUE;
2024 vdev_reopen(spa->spa_root_vdev);
2025 spa->spa_scrub_reopen = B_FALSE;
2026 (void) spa_vdev_state_exit(spa, NULL, 0);
2027
2028 if (func == POOL_SCAN_SCRUB && dsl_scan_is_paused_scrub(scn)) {
2029 /* got scrub start cmd, resume paused scrub */
2030 int err = dsl_scrub_set_pause_resume(scn->scn_dp,
2031 POOL_SCRUB_NORMAL);
2032 if (err == 0) {
2033 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_RESUME);
2034 return (ECANCELED);
2035 }
2036
2037 return (SET_ERROR(err));
2038 }
2039
2040 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
2041 dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_NONE));
2042 }
2043
2044 static boolean_t
2045 dsl_scan_restarting(dsl_scan_t *scn, dmu_tx_t *tx)
2046 {
2047 return (scn->scn_restart_txg != 0 &&
2048 scn->scn_restart_txg <= tx->tx_txg);
2049 }
|
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 2017 Nexenta Systems, Inc. All rights reserved.
24 * Copyright 2016 Gary Mills
25 * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
26 * Copyright 2017 Joyent, Inc.
27 * Copyright (c) 2017 Datto Inc.
28 */
29
30 #include <sys/dsl_scan.h>
31 #include <sys/dsl_pool.h>
32 #include <sys/dsl_dataset.h>
33 #include <sys/dsl_prop.h>
34 #include <sys/dsl_dir.h>
35 #include <sys/dsl_synctask.h>
36 #include <sys/dnode.h>
37 #include <sys/dmu_tx.h>
38 #include <sys/dmu_objset.h>
39 #include <sys/arc.h>
40 #include <sys/zap.h>
41 #include <sys/zio.h>
42 #include <sys/zfs_context.h>
43 #include <sys/fs/zfs.h>
44 #include <sys/zfs_znode.h>
45 #include <sys/spa_impl.h>
46 #include <sys/vdev_impl.h>
47 #include <sys/zil_impl.h>
48 #include <sys/zio_checksum.h>
49 #include <sys/ddt.h>
50 #include <sys/sa.h>
51 #include <sys/sa_impl.h>
52 #include <sys/zfeature.h>
53 #include <sys/abd.h>
54 #ifdef _KERNEL
55 #include <sys/zfs_vfsops.h>
56 #endif
57 #include <sys/range_tree.h>
58
59 extern int zfs_vdev_async_write_active_min_dirty_percent;
60
61 typedef struct {
62 uint64_t sds_dsobj;
63 uint64_t sds_txg;
64 avl_node_t sds_node;
65 } scan_ds_t;
66
67 typedef struct {
68 dsl_scan_io_queue_t *qri_queue;
69 uint64_t qri_limit;
70 } io_queue_run_info_t;
71
72 /*
73 * This controls what conditions are placed on dsl_scan_sync_state():
74 * SYNC_OPTIONAL) write out scn_phys iff scn_bytes_pending == 0
75 * SYNC_MANDATORY) write out scn_phys always. scn_bytes_pending must be 0.
76 * SYNC_CACHED) if scn_bytes_pending == 0, write out scn_phys. Otherwise
77 * write out the scn_phys_cached version.
78 * See dsl_scan_sync_state for details.
79 */
80 typedef enum {
81 SYNC_OPTIONAL,
82 SYNC_MANDATORY,
83 SYNC_CACHED
84 } state_sync_type_t;
85
86 typedef int (scan_cb_t)(dsl_pool_t *, const blkptr_t *,
87 const zbookmark_phys_t *);
88
89 static scan_cb_t dsl_scan_scrub_cb;
90 static void dsl_scan_cancel_sync(void *, dmu_tx_t *);
91 static void dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx,
92 state_sync_type_t sync_type);
93 static boolean_t dsl_scan_restarting(dsl_scan_t *, dmu_tx_t *);
94
95 static int scan_ds_queue_compar(const void *a, const void *b);
96 static void scan_ds_queue_empty(dsl_scan_t *scn, boolean_t destroy);
97 static boolean_t scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj,
98 uint64_t *txg);
99 static int scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg);
100 static void scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj);
101 static boolean_t scan_ds_queue_first(dsl_scan_t *scn, uint64_t *dsobj,
102 uint64_t *txg);
103 static void scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx);
104
105 /*
106 * Maximum number of parallelly executing I/Os per top-level vdev.
107 * Tune with care. Very high settings (hundreds) are known to trigger
108 * some firmware bugs and resets on certain SSDs.
109 */
110 int zfs_top_maxinflight = 32;
111
112 /*
113 * Minimum amount of data we dequeue if our queues are full and the
114 * dirty data limit for a txg has been reached.
115 */
116 uint64_t zfs_scan_dequeue_min = 16 << 20;
117 /*
118 * The duration target we're aiming for a dsl_scan_sync to take due to our
119 * dequeued data. If we go over that value, we lower the amount we dequeue
120 * each run and vice versa. The bonus value below is just something we add
121 * on top of he target value so that we have a little bit of fudging in case
122 * some top-level vdevs finish before others - we want to keep the vdevs as
123 * hot as possible.
124 */
125 uint64_t zfs_scan_dequeue_run_target_ms = 2000;
126 uint64_t zfs_dequeue_run_bonus_ms = 1000;
127 #define DEQUEUE_BONUS_MS_MAX 100000
128
129 boolean_t zfs_scan_direct = B_FALSE; /* don't queue & sort zios, go direct */
130 uint64_t zfs_scan_max_ext_gap = 2 << 20; /* bytes */
131 /* See scan_io_queue_mem_lim for details on the memory limit tunables */
132 uint64_t zfs_scan_mem_lim_fact = 20; /* fraction of physmem */
133 uint64_t zfs_scan_mem_lim_soft_fact = 20; /* fraction of mem lim above */
134 uint64_t zfs_scan_checkpoint_intval = 7200; /* seconds */
135 /*
136 * fill_weight is non-tunable at runtime, so we copy it at module init from
137 * zfs_scan_fill_weight. Runtime adjustments to zfs_scan_fill_weight would
138 * break queue sorting.
139 */
140 uint64_t zfs_scan_fill_weight = 3;
141 static uint64_t fill_weight = 3;
142
143 /* See scan_io_queue_mem_lim for details on the memory limit tunables */
144 uint64_t zfs_scan_mem_lim_min = 16 << 20; /* bytes */
145 uint64_t zfs_scan_mem_lim_soft_max = 128 << 20; /* bytes */
146
147 #define ZFS_SCAN_CHECKPOINT_INTVAL SEC_TO_TICK(zfs_scan_checkpoint_intval)
148
149 int zfs_scan_min_time_ms = 1000; /* min millisecs to scrub per txg */
150 int zfs_free_min_time_ms = 1000; /* min millisecs to free per txg */
151 int zfs_resilver_min_time_ms = 3000; /* min millisecs to resilver per txg */
152 boolean_t zfs_no_scrub_io = B_FALSE; /* set to disable scrub i/o */
153 boolean_t zfs_no_scrub_prefetch = B_FALSE; /* set to disable scrub prefetch */
154 enum ddt_class zfs_scrub_ddt_class_max = DDT_CLASS_DUPLICATE;
155 int dsl_scan_delay_completion = B_FALSE; /* set to delay scan completion */
156 /* max number of blocks to free in a single TXG */
157 uint64_t zfs_free_max_blocks = UINT64_MAX;
158
159 #define DSL_SCAN_IS_SCRUB_RESILVER(scn) \
160 ((scn)->scn_phys.scn_func == POOL_SCAN_SCRUB || \
161 (scn)->scn_phys.scn_func == POOL_SCAN_RESILVER || \
162 (scn)->scn_phys.scn_func == POOL_SCAN_MOS || \
163 (scn)->scn_phys.scn_func == POOL_SCAN_META)
164
165 extern int zfs_txg_timeout;
166
167 /*
168 * Enable/disable the processing of the free_bpobj object.
169 */
170 boolean_t zfs_free_bpobj_enabled = B_TRUE;
171
172 /* the order has to match pool_scan_type */
173 static scan_cb_t *scan_funcs[POOL_SCAN_FUNCS] = {
174 NULL,
175 dsl_scan_scrub_cb, /* POOL_SCAN_SCRUB */
176 dsl_scan_scrub_cb, /* POOL_SCAN_RESILVER */
177 dsl_scan_scrub_cb, /* POOL_SCAN_MOS */
178 dsl_scan_scrub_cb, /* POOL_SCAN_META */
179 };
180
181 typedef struct scan_io {
182 uint64_t sio_prop;
183 uint64_t sio_phys_birth;
184 uint64_t sio_birth;
185 zio_cksum_t sio_cksum;
186 zbookmark_phys_t sio_zb;
187 union {
188 avl_node_t sio_addr_node;
189 list_node_t sio_list_node;
190 } sio_nodes;
191 uint64_t sio_dva_word1;
192 uint32_t sio_asize;
193 int sio_flags;
194 } scan_io_t;
195
196 struct dsl_scan_io_queue {
197 dsl_scan_t *q_scn;
198 vdev_t *q_vd;
199
200 kcondvar_t q_cv;
201
202 range_tree_t *q_exts_by_addr;
203 avl_tree_t q_zios_by_addr;
204 avl_tree_t q_exts_by_size;
205
206 /* number of bytes in queued zios - atomic ops */
207 uint64_t q_zio_bytes;
208
209 range_seg_t q_issuing_rs;
210 uint64_t q_num_issuing_zios;
211 };
212
213 #define SCAN_IO_GET_OFFSET(sio) \
214 BF64_GET_SB((sio)->sio_dva_word1, 0, 63, SPA_MINBLOCKSHIFT, 0)
215 #define SCAN_IO_SET_OFFSET(sio, offset) \
216 BF64_SET_SB((sio)->sio_dva_word1, 0, 63, SPA_MINBLOCKSHIFT, 0, offset)
217
218 static void scan_io_queue_insert_cb(range_tree_t *rt, range_seg_t *rs,
219 void *arg);
220 static void scan_io_queue_remove_cb(range_tree_t *rt, range_seg_t *rs,
221 void *arg);
222 static void scan_io_queue_vacate_cb(range_tree_t *rt, void *arg);
223 static int ext_size_compar(const void *x, const void *y);
224 static int io_addr_compar(const void *x, const void *y);
225
226 static struct range_tree_ops scan_io_queue_ops = {
227 .rtop_create = NULL,
228 .rtop_destroy = NULL,
229 .rtop_add = scan_io_queue_insert_cb,
230 .rtop_remove = scan_io_queue_remove_cb,
231 .rtop_vacate = scan_io_queue_vacate_cb
232 };
233
234 typedef enum {
235 MEM_LIM_NONE,
236 MEM_LIM_SOFT,
237 MEM_LIM_HARD
238 } mem_lim_t;
239
240 static void dsl_scan_enqueue(dsl_pool_t *dp, const blkptr_t *bp,
241 int zio_flags, const zbookmark_phys_t *zb);
242 static void scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
243 const zbookmark_phys_t *zb, boolean_t limit_inflight);
244 static void scan_io_queue_insert(dsl_scan_t *scn, dsl_scan_io_queue_t *queue,
245 const blkptr_t *bp, int dva_i, int zio_flags, const zbookmark_phys_t *zb);
246
247 static void scan_io_queues_run_one(io_queue_run_info_t *info);
248 static void scan_io_queues_run(dsl_scan_t *scn);
249 static mem_lim_t scan_io_queue_mem_lim(dsl_scan_t *scn);
250
251 static dsl_scan_io_queue_t *scan_io_queue_create(vdev_t *vd);
252 static void scan_io_queues_destroy(dsl_scan_t *scn);
253 static void dsl_scan_freed_dva(spa_t *spa, const blkptr_t *bp, int dva_i);
254
255 static inline boolean_t
256 dsl_scan_is_running(const dsl_scan_t *scn)
257 {
258 return (scn->scn_phys.scn_state == DSS_SCANNING ||
259 scn->scn_phys.scn_state == DSS_FINISHING);
260 }
261
262 static inline void
263 sio2bp(const scan_io_t *sio, blkptr_t *bp, uint64_t vdev_id)
264 {
265 bzero(bp, sizeof (*bp));
266 DVA_SET_ASIZE(&bp->blk_dva[0], sio->sio_asize);
267 DVA_SET_VDEV(&bp->blk_dva[0], vdev_id);
268 bp->blk_dva[0].dva_word[1] = sio->sio_dva_word1;
269 bp->blk_prop = sio->sio_prop;
270 /*
271 * We must reset the special flag, because the rebuilt BP lacks
272 * a second DVA, so wbc_select_dva must not be allowed to run.
273 */
274 BP_SET_SPECIAL(bp, 0);
275 bp->blk_phys_birth = sio->sio_phys_birth;
276 bp->blk_birth = sio->sio_birth;
277 bp->blk_fill = 1; /* we always only work with data pointers */
278 bp->blk_cksum = sio->sio_cksum;
279 }
280
281 static inline void
282 bp2sio(const blkptr_t *bp, scan_io_t *sio, int dva_i)
283 {
284 if (BP_IS_SPECIAL(bp))
285 ASSERT3S(dva_i, ==, WBC_NORMAL_DVA);
286 /* we discard the vdev guid, since we can deduce it from the queue */
287 sio->sio_dva_word1 = bp->blk_dva[dva_i].dva_word[1];
288 sio->sio_asize = DVA_GET_ASIZE(&bp->blk_dva[dva_i]);
289 sio->sio_prop = bp->blk_prop;
290 sio->sio_phys_birth = bp->blk_phys_birth;
291 sio->sio_birth = bp->blk_birth;
292 sio->sio_cksum = bp->blk_cksum;
293 }
294
295 void
296 dsl_scan_global_init()
297 {
298 fill_weight = zfs_scan_fill_weight;
299 }
300
301 int
302 dsl_scan_init(dsl_pool_t *dp, uint64_t txg)
303 {
304 int err;
305 dsl_scan_t *scn;
306 spa_t *spa = dp->dp_spa;
307 uint64_t f;
308
309 scn = dp->dp_scan = kmem_zalloc(sizeof (dsl_scan_t), KM_SLEEP);
310 scn->scn_dp = dp;
311
312 mutex_init(&scn->scn_sorted_lock, NULL, MUTEX_DEFAULT, NULL);
313 mutex_init(&scn->scn_status_lock, NULL, MUTEX_DEFAULT, NULL);
314
315 /*
316 * It's possible that we're resuming a scan after a reboot so
317 * make sure that the scan_async_destroying flag is initialized
318 * appropriately.
319 */
320 ASSERT(!scn->scn_async_destroying);
321 scn->scn_async_destroying = spa_feature_is_active(dp->dp_spa,
322 SPA_FEATURE_ASYNC_DESTROY);
323
324 bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
325 mutex_init(&scn->scn_queue_lock, NULL, MUTEX_DEFAULT, NULL);
326 avl_create(&scn->scn_queue, scan_ds_queue_compar, sizeof (scan_ds_t),
327 offsetof(scan_ds_t, sds_node));
328
329 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
330 "scrub_func", sizeof (uint64_t), 1, &f);
331 if (err == 0) {
332 /*
333 * There was an old-style scrub in progress. Restart a
334 * new-style scrub from the beginning.
335 */
336 scn->scn_restart_txg = txg;
337 DTRACE_PROBE2(scan_init__old2new, dsl_scan_t *, scn,
338 uint64_t, txg);
339 zfs_dbgmsg("old-style scrub was in progress; "
340 "restarting new-style scrub in txg %llu",
341 scn->scn_restart_txg);
342
343 /*
344 * Load the queue obj from the old location so that it
345 * can be freed by dsl_scan_done().
346 */
347 (void) zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
348 "scrub_queue", sizeof (uint64_t), 1,
349 &scn->scn_phys.scn_queue_obj);
350 } else {
351 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
352 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
353 &scn->scn_phys);
354 if (err == ENOENT)
355 return (0);
356 else if (err)
357 return (err);
358
359 /*
360 * We might be restarting after a reboot, so jump the issued
361 * counter to how far we've scanned. We know we're consistent
362 * up to here.
363 */
364 scn->scn_bytes_issued = scn->scn_phys.scn_examined;
365
366 if (dsl_scan_is_running(scn) &&
367 spa_prev_software_version(dp->dp_spa) < SPA_VERSION_SCAN) {
368 /*
369 * A new-type scrub was in progress on an old
370 * pool, and the pool was accessed by old
371 * software. Restart from the beginning, since
372 * the old software may have changed the pool in
373 * the meantime.
374 */
375 scn->scn_restart_txg = txg;
376 DTRACE_PROBE2(scan_init__new2old2new,
377 dsl_scan_t *, scn, uint64_t, txg);
378 zfs_dbgmsg("new-style scrub was modified "
379 "by old software; restarting in txg %llu",
380 scn->scn_restart_txg);
381 }
382 }
383
384 /* reload the queue into the in-core state */
385 if (scn->scn_phys.scn_queue_obj != 0) {
386 zap_cursor_t zc;
387 zap_attribute_t za;
388
389 for (zap_cursor_init(&zc, dp->dp_meta_objset,
390 scn->scn_phys.scn_queue_obj);
391 zap_cursor_retrieve(&zc, &za) == 0;
392 (void) zap_cursor_advance(&zc)) {
393 VERIFY0(scan_ds_queue_insert(scn,
394 zfs_strtonum(za.za_name, NULL),
395 za.za_first_integer));
396 }
397 zap_cursor_fini(&zc);
398 }
399
400 spa_scan_stat_init(spa);
401 return (0);
402 }
403
404 void
405 dsl_scan_fini(dsl_pool_t *dp)
406 {
407 if (dp->dp_scan != NULL) {
408 dsl_scan_t *scn = dp->dp_scan;
409
410 mutex_destroy(&scn->scn_sorted_lock);
411 mutex_destroy(&scn->scn_status_lock);
412 if (scn->scn_taskq != NULL)
413 taskq_destroy(scn->scn_taskq);
414 scan_ds_queue_empty(scn, B_TRUE);
415 mutex_destroy(&scn->scn_queue_lock);
416
417 kmem_free(dp->dp_scan, sizeof (dsl_scan_t));
418 dp->dp_scan = NULL;
419 }
420 }
421
422 /* ARGSUSED */
423 static int
424 dsl_scan_setup_check(void *arg, dmu_tx_t *tx)
425 {
426 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
427
428 if (dsl_scan_is_running(scn))
429 return (SET_ERROR(EBUSY));
430
431 return (0);
432 }
433
434 static void
435 dsl_scan_setup_sync(void *arg, dmu_tx_t *tx)
436 {
437 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
438 pool_scan_func_t *funcp = arg;
439 dmu_object_type_t ot = 0;
440 dsl_pool_t *dp = scn->scn_dp;
441 spa_t *spa = dp->dp_spa;
442
443 ASSERT(!dsl_scan_is_running(scn));
444 ASSERT(*funcp > POOL_SCAN_NONE && *funcp < POOL_SCAN_FUNCS);
445 bzero(&scn->scn_phys, sizeof (scn->scn_phys));
446 scn->scn_phys.scn_func = *funcp;
447 scn->scn_phys.scn_state = DSS_SCANNING;
448 scn->scn_phys.scn_min_txg = 0;
449 scn->scn_phys.scn_max_txg = tx->tx_txg;
450 /* the entire DDT */
451 scn->scn_phys.scn_ddt_class_max = spa->spa_ddt_class_max;
452 scn->scn_phys.scn_start_time = gethrestime_sec();
453 scn->scn_phys.scn_errors = 0;
454 scn->scn_phys.scn_to_examine = spa->spa_root_vdev->vdev_stat.vs_alloc;
455 scn->scn_restart_txg = 0;
456 scn->scn_done_txg = 0;
457 scn->scn_bytes_issued = 0;
458 scn->scn_checkpointing = B_FALSE;
459 scn->scn_last_checkpoint = 0;
460 spa_scan_stat_init(spa);
461
462 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
463 scn->scn_phys.scn_ddt_class_max =
464 MIN(zfs_scrub_ddt_class_max, spa->spa_ddt_class_max);
465
466 /* rewrite all disk labels */
467 vdev_config_dirty(spa->spa_root_vdev);
468
469 if (vdev_resilver_needed(spa->spa_root_vdev,
470 &scn->scn_phys.scn_min_txg, &scn->scn_phys.scn_max_txg)) {
471 spa_event_notify(spa, NULL, NULL,
472 ESC_ZFS_RESILVER_START);
473 } else {
474 spa_event_notify(spa, NULL, NULL, ESC_ZFS_SCRUB_START);
475 }
476
477 spa->spa_scrub_started = B_TRUE;
478 /*
479 * If this is an incremental scrub, limit the DDT scrub phase
480 * to just the auto-ditto class (for correctness); the rest
481 * of the scrub should go faster using top-down pruning.
482 */
483 if (scn->scn_phys.scn_min_txg > TXG_INITIAL)
484 scn->scn_phys.scn_ddt_class_max =
485 MIN(DDT_CLASS_DITTO, spa->spa_ddt_class_max);
486
487 }
488
489 /* back to the generic stuff */
490
491 if (dp->dp_blkstats == NULL) {
492 dp->dp_blkstats =
493 kmem_alloc(sizeof (zfs_all_blkstats_t), KM_SLEEP);
494 }
495 bzero(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
496
497 if (spa_version(spa) < SPA_VERSION_DSL_SCRUB)
498 ot = DMU_OT_ZAP_OTHER;
499
500 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset,
501 ot ? ot : DMU_OT_SCAN_QUEUE, DMU_OT_NONE, 0, tx);
502
503 bcopy(&scn->scn_phys, &scn->scn_phys_cached, sizeof (scn->scn_phys));
504
505 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
506
507 spa_history_log_internal(spa, "scan setup", tx,
508 "func=%u mintxg=%llu maxtxg=%llu",
509 *funcp, scn->scn_phys.scn_min_txg, scn->scn_phys.scn_max_txg);
510 }
511
512 /* ARGSUSED */
513 static void
514 dsl_scan_done(dsl_scan_t *scn, boolean_t complete, dmu_tx_t *tx)
515 {
516 static const char *old_names[] = {
517 "scrub_bookmark",
518 "scrub_ddt_bookmark",
519 "scrub_ddt_class_max",
520 "scrub_queue",
521 "scrub_min_txg",
522 "scrub_max_txg",
523 "scrub_func",
524 "scrub_errors",
525 NULL
526 };
527
528 dsl_pool_t *dp = scn->scn_dp;
529 spa_t *spa = dp->dp_spa;
530 int i;
531
532 /* Remove any remnants of an old-style scrub. */
533 for (i = 0; old_names[i]; i++) {
534 (void) zap_remove(dp->dp_meta_objset,
535 DMU_POOL_DIRECTORY_OBJECT, old_names[i], tx);
536 }
537
538 if (scn->scn_phys.scn_queue_obj != 0) {
539 VERIFY0(dmu_object_free(dp->dp_meta_objset,
540 scn->scn_phys.scn_queue_obj, tx));
541 scn->scn_phys.scn_queue_obj = 0;
542 }
543 scan_ds_queue_empty(scn, B_FALSE);
544
545 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
546
547 /*
548 * If we were "restarted" from a stopped state, don't bother
549 * with anything else.
550 */
551 if (!dsl_scan_is_running(scn)) {
552 ASSERT(!scn->scn_is_sorted);
553 return;
554 }
555
556 if (scn->scn_is_sorted) {
557 scan_io_queues_destroy(scn);
558 scn->scn_is_sorted = B_FALSE;
559
560 if (scn->scn_taskq != NULL) {
561 taskq_destroy(scn->scn_taskq);
562 scn->scn_taskq = NULL;
563 }
564 }
565
566 scn->scn_phys.scn_state = complete ? DSS_FINISHED : DSS_CANCELED;
567
568 if (dsl_scan_restarting(scn, tx))
569 spa_history_log_internal(spa, "scan aborted, restarting", tx,
570 "errors=%llu", spa_get_errlog_size(spa));
571 else if (!complete)
572 spa_history_log_internal(spa, "scan cancelled", tx,
573 "errors=%llu", spa_get_errlog_size(spa));
574 else
575 spa_history_log_internal(spa, "scan done", tx,
576 "errors=%llu", spa_get_errlog_size(spa));
577
578 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
579 mutex_enter(&spa->spa_scrub_lock);
580 while (spa->spa_scrub_inflight > 0) {
581 cv_wait(&spa->spa_scrub_io_cv,
582 &spa->spa_scrub_lock);
583 }
584 mutex_exit(&spa->spa_scrub_lock);
585 spa->spa_scrub_started = B_FALSE;
586 spa->spa_scrub_active = B_FALSE;
587
590 * reflect this. Whether it succeeded or not, vacate
591 * all temporary scrub DTLs.
592 */
593 vdev_dtl_reassess(spa->spa_root_vdev, tx->tx_txg,
594 complete ? scn->scn_phys.scn_max_txg : 0, B_TRUE);
595 if (complete) {
596 spa_event_notify(spa, NULL, NULL,
597 scn->scn_phys.scn_min_txg ?
598 ESC_ZFS_RESILVER_FINISH : ESC_ZFS_SCRUB_FINISH);
599 }
600 spa_errlog_rotate(spa);
601
602 /*
603 * We may have finished replacing a device.
604 * Let the async thread assess this and handle the detach.
605 */
606 spa_async_request(spa, SPA_ASYNC_RESILVER_DONE);
607 }
608
609 scn->scn_phys.scn_end_time = gethrestime_sec();
610
611 ASSERT(!dsl_scan_is_running(scn));
612
613 /*
614 * If the special-vdev does not have any errors after
615 * SCRUB/RESILVER we need to drop flag that does not
616 * allow to write to special
617 */
618 spa_special_check_errors(spa);
619 }
620
621 /* ARGSUSED */
622 static int
623 dsl_scan_cancel_check(void *arg, dmu_tx_t *tx)
624 {
625 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
626
627 if (!dsl_scan_is_running(scn))
628 return (SET_ERROR(ENOENT));
629 return (0);
630 }
631
632 /* ARGSUSED */
633 static void
634 dsl_scan_cancel_sync(void *arg, dmu_tx_t *tx)
635 {
636 dsl_scan_t *scn = dmu_tx_pool(tx)->dp_scan;
637
638 dsl_scan_done(scn, B_FALSE, tx);
639 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
640 }
641
642 int
643 dsl_scan_cancel(dsl_pool_t *dp)
644 {
645 return (dsl_sync_task(spa_name(dp->dp_spa), dsl_scan_cancel_check,
646 dsl_scan_cancel_sync, NULL, 3, ZFS_SPACE_CHECK_RESERVED));
647 }
648
649 boolean_t
650 dsl_scan_is_paused_scrub(const dsl_scan_t *scn)
651 {
652 if (dsl_scan_scrubbing(scn->scn_dp) &&
653 scn->scn_phys.scn_flags & DSF_SCRUB_PAUSED)
654 return (B_TRUE);
655
656 return (B_FALSE);
657 }
658
659 static int
673 return (SET_ERROR(EBUSY));
674 } else if (*cmd != POOL_SCRUB_NORMAL) {
675 return (SET_ERROR(ENOTSUP));
676 }
677
678 return (0);
679 }
680
681 static void
682 dsl_scrub_pause_resume_sync(void *arg, dmu_tx_t *tx)
683 {
684 pool_scrub_cmd_t *cmd = arg;
685 dsl_pool_t *dp = dmu_tx_pool(tx);
686 spa_t *spa = dp->dp_spa;
687 dsl_scan_t *scn = dp->dp_scan;
688
689 if (*cmd == POOL_SCRUB_PAUSE) {
690 /* can't pause a scrub when there is no in-progress scrub */
691 spa->spa_scan_pass_scrub_pause = gethrestime_sec();
692 scn->scn_phys.scn_flags |= DSF_SCRUB_PAUSED;
693 scn->scn_phys_cached.scn_flags |= DSF_SCRUB_PAUSED;
694 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
695 } else {
696 ASSERT3U(*cmd, ==, POOL_SCRUB_NORMAL);
697 if (dsl_scan_is_paused_scrub(scn)) {
698 /*
699 * We need to keep track of how much time we spend
700 * paused per pass so that we can adjust the scrub rate
701 * shown in the output of 'zpool status'
702 */
703 spa->spa_scan_pass_scrub_spent_paused +=
704 gethrestime_sec() - spa->spa_scan_pass_scrub_pause;
705 spa->spa_scan_pass_scrub_pause = 0;
706 scn->scn_phys.scn_flags &= ~DSF_SCRUB_PAUSED;
707 scn->scn_phys_cached.scn_flags &= ~DSF_SCRUB_PAUSED;
708 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
709 }
710 }
711 }
712
713 /*
714 * Set scrub pause/resume state if it makes sense to do so
715 */
716 int
717 dsl_scrub_set_pause_resume(const dsl_pool_t *dp, pool_scrub_cmd_t cmd)
718 {
719 return (dsl_sync_task(spa_name(dp->dp_spa),
720 dsl_scrub_pause_resume_check, dsl_scrub_pause_resume_sync, &cmd, 3,
721 ZFS_SPACE_CHECK_RESERVED));
722 }
723
724 boolean_t
725 dsl_scan_scrubbing(const dsl_pool_t *dp)
726 {
727 dsl_scan_t *scn = dp->dp_scan;
728
729 if ((scn->scn_phys.scn_state == DSS_SCANNING ||
730 scn->scn_phys.scn_state == DSS_FINISHING) &&
731 scn->scn_phys.scn_func == POOL_SCAN_SCRUB)
732 return (B_TRUE);
733
734 return (B_FALSE);
735 }
736
737 static void dsl_scan_visitbp(blkptr_t *bp, const zbookmark_phys_t *zb,
738 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
739 dmu_objset_type_t ostype, dmu_tx_t *tx);
740 static void dsl_scan_visitdnode(dsl_scan_t *, dsl_dataset_t *ds,
741 dmu_objset_type_t ostype,
742 dnode_phys_t *dnp, uint64_t object, dmu_tx_t *tx);
743
744 void
745 dsl_free(dsl_pool_t *dp, uint64_t txg, const blkptr_t *bp)
746 {
747 zio_free(dp->dp_spa, txg, bp);
748 }
749
750 void
751 dsl_free_sync(zio_t *pio, dsl_pool_t *dp, uint64_t txg, const blkptr_t *bpp)
752 {
753 ASSERT(dsl_pool_sync_context(dp));
754 zio_nowait(zio_free_sync(pio, dp->dp_spa, txg, bpp, pio->io_flags));
755 }
756
757 static uint64_t
758 dsl_scan_ds_maxtxg(dsl_dataset_t *ds)
759 {
760 uint64_t smt = ds->ds_dir->dd_pool->dp_scan->scn_phys.scn_max_txg;
761 if (ds->ds_is_snapshot)
762 return (MIN(smt, dsl_dataset_phys(ds)->ds_creation_txg));
763 return (smt);
764 }
765
766 /*
767 * This is the dataset processing "queue", i.e. the datasets that are to be
768 * scanned for data locations and inserted into the LBA reordering tree.
769 * Please note that even though we call this a "queue", the actual
770 * implementation uses an avl tree (to detect double insertion). The tree
771 * uses the dataset object set number for the sorting criterion, so
772 * scan_ds_queue_insert CANNOT be guaranteed to always append stuff at the
773 * end (datasets are inserted by the scanner in discovery order, i.e.
774 * parent-child relationships). Consequently, the scanner must never step
775 * through the AVL tree in a naively sequential fashion using AVL_NEXT.
776 * We must always use scan_ds_queue_first to pick the first dataset in the
777 * list, process it, remove it using scan_ds_queue_remove and pick the next
778 * first dataset, again using scan_ds_queue_first.
779 */
780 static int
781 scan_ds_queue_compar(const void *a, const void *b)
782 {
783 const scan_ds_t *sds_a = a, *sds_b = b;
784
785 if (sds_a->sds_dsobj < sds_b->sds_dsobj)
786 return (-1);
787 if (sds_a->sds_dsobj == sds_b->sds_dsobj)
788 return (0);
789 return (1);
790 }
791
792 static void
793 scan_ds_queue_empty(dsl_scan_t *scn, boolean_t destroy)
794 {
795 void *cookie = NULL;
796 scan_ds_t *sds;
797
798 mutex_enter(&scn->scn_queue_lock);
799 while ((sds = avl_destroy_nodes(&scn->scn_queue, &cookie)) != NULL)
800 kmem_free(sds, sizeof (*sds));
801 mutex_exit(&scn->scn_queue_lock);
802
803 if (destroy)
804 avl_destroy(&scn->scn_queue);
805 }
806
807 static boolean_t
808 scan_ds_queue_contains(dsl_scan_t *scn, uint64_t dsobj, uint64_t *txg)
809 {
810 scan_ds_t *sds;
811 scan_ds_t srch = { .sds_dsobj = dsobj };
812
813 mutex_enter(&scn->scn_queue_lock);
814 sds = avl_find(&scn->scn_queue, &srch, NULL);
815 if (sds != NULL && txg != NULL)
816 *txg = sds->sds_txg;
817 mutex_exit(&scn->scn_queue_lock);
818
819 return (sds != NULL);
820 }
821
822 static int
823 scan_ds_queue_insert(dsl_scan_t *scn, uint64_t dsobj, uint64_t txg)
824 {
825 scan_ds_t *sds;
826 avl_index_t where;
827
828 sds = kmem_zalloc(sizeof (*sds), KM_SLEEP);
829 sds->sds_dsobj = dsobj;
830 sds->sds_txg = txg;
831
832 mutex_enter(&scn->scn_queue_lock);
833 if (avl_find(&scn->scn_queue, sds, &where) != NULL) {
834 kmem_free(sds, sizeof (*sds));
835 return (EEXIST);
836 }
837 avl_insert(&scn->scn_queue, sds, where);
838 mutex_exit(&scn->scn_queue_lock);
839
840 return (0);
841 }
842
843 static void
844 scan_ds_queue_remove(dsl_scan_t *scn, uint64_t dsobj)
845 {
846 scan_ds_t srch, *sds;
847
848 srch.sds_dsobj = dsobj;
849
850 mutex_enter(&scn->scn_queue_lock);
851 sds = avl_find(&scn->scn_queue, &srch, NULL);
852 VERIFY(sds != NULL);
853 avl_remove(&scn->scn_queue, sds);
854 mutex_exit(&scn->scn_queue_lock);
855
856 kmem_free(sds, sizeof (*sds));
857 }
858
859 static boolean_t
860 scan_ds_queue_first(dsl_scan_t *scn, uint64_t *dsobj, uint64_t *txg)
861 {
862 scan_ds_t *sds;
863
864 mutex_enter(&scn->scn_queue_lock);
865 sds = avl_first(&scn->scn_queue);
866 if (sds != NULL) {
867 *dsobj = sds->sds_dsobj;
868 *txg = sds->sds_txg;
869 }
870 mutex_exit(&scn->scn_queue_lock);
871
872 return (sds != NULL);
873 }
874
875 static void
876 scan_ds_queue_sync(dsl_scan_t *scn, dmu_tx_t *tx)
877 {
878 dsl_pool_t *dp = scn->scn_dp;
879 spa_t *spa = dp->dp_spa;
880 dmu_object_type_t ot = (spa_version(spa) >= SPA_VERSION_DSL_SCRUB) ?
881 DMU_OT_SCAN_QUEUE : DMU_OT_ZAP_OTHER;
882
883 ASSERT0(scn->scn_bytes_pending);
884 ASSERT(scn->scn_phys.scn_queue_obj != 0);
885
886 VERIFY0(dmu_object_free(dp->dp_meta_objset,
887 scn->scn_phys.scn_queue_obj, tx));
888 scn->scn_phys.scn_queue_obj = zap_create(dp->dp_meta_objset, ot,
889 DMU_OT_NONE, 0, tx);
890
891 mutex_enter(&scn->scn_queue_lock);
892 for (scan_ds_t *sds = avl_first(&scn->scn_queue);
893 sds != NULL; sds = AVL_NEXT(&scn->scn_queue, sds)) {
894 VERIFY0(zap_add_int_key(dp->dp_meta_objset,
895 scn->scn_phys.scn_queue_obj, sds->sds_dsobj,
896 sds->sds_txg, tx));
897 }
898 mutex_exit(&scn->scn_queue_lock);
899 }
900
901 /*
902 * Writes out a persistent dsl_scan_phys_t record to the pool directory.
903 * Because we can be running in the block sorting algorithm, we do not always
904 * want to write out the record, only when it is "safe" to do so. This safety
905 * condition is achieved by making sure that the sorting queues are empty
906 * (scn_bytes_pending==0). The sync'ed state could be inconsistent with how
907 * much actual scanning progress has been made. What kind of sync is performed
908 * specified by the sync_type argument. If the sync is optional, we only
909 * sync if the queues are empty. If the sync is mandatory, we do a hard VERIFY
910 * to make sure that the queues are empty. The third possible state is a
911 * "cached" sync. This is done in response to:
912 * 1) The dataset that was in the last sync'ed dsl_scan_phys_t having been
913 * destroyed, so we wouldn't be able to restart scanning from it.
914 * 2) The snapshot that was in the last sync'ed dsl_scan_phys_t having been
915 * superseded by a newer snapshot.
916 * 3) The dataset that was in the last sync'ed dsl_scan_phys_t having been
917 * swapped with its clone.
918 * In all cases, a cached sync simply rewrites the last record we've written,
919 * just slightly modified. For the modifications that are performed to the
920 * last written dsl_scan_phys_t, see dsl_scan_ds_destroyed,
921 * dsl_scan_ds_snapshotted and dsl_scan_ds_clone_swapped.
922 */
923 static void
924 dsl_scan_sync_state(dsl_scan_t *scn, dmu_tx_t *tx, state_sync_type_t sync_type)
925 {
926 mutex_enter(&scn->scn_status_lock);
927 ASSERT(sync_type != SYNC_MANDATORY || scn->scn_bytes_pending == 0);
928 if (scn->scn_bytes_pending == 0) {
929 if (scn->scn_phys.scn_queue_obj != 0)
930 scan_ds_queue_sync(scn, tx);
931 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
932 DMU_POOL_DIRECTORY_OBJECT,
933 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
934 &scn->scn_phys, tx));
935 bcopy(&scn->scn_phys, &scn->scn_phys_cached,
936 sizeof (scn->scn_phys));
937 scn->scn_checkpointing = B_FALSE;
938 scn->scn_last_checkpoint = ddi_get_lbolt();
939 } else if (sync_type == SYNC_CACHED) {
940 VERIFY0(zap_update(scn->scn_dp->dp_meta_objset,
941 DMU_POOL_DIRECTORY_OBJECT,
942 DMU_POOL_SCAN, sizeof (uint64_t), SCAN_PHYS_NUMINTS,
943 &scn->scn_phys_cached, tx));
944 }
945 mutex_exit(&scn->scn_status_lock);
946 }
947
948 static boolean_t
949 dsl_scan_check_suspend(dsl_scan_t *scn, const zbookmark_phys_t *zb)
950 {
951 /* we never skip user/group accounting objects */
952 if (zb && (int64_t)zb->zb_object < 0)
953 return (B_FALSE);
954
955 if (scn->scn_suspending)
956 return (B_TRUE); /* we're already suspending */
957
958 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark))
959 return (B_FALSE); /* we're resuming */
960
961 /* We only know how to resume from level-0 blocks. */
962 if (zb && zb->zb_level != 0)
963 return (B_FALSE);
964
965 /*
966 * We suspend if:
967 * - we have scanned for the maximum time: an entire txg
968 * timeout (default 5 sec)
969 * or
970 * - we have scanned for at least the minimum time (default 1 sec
971 * for scrub, 3 sec for resilver), and either we have sufficient
972 * dirty data that we are starting to write more quickly
973 * (default 30%), or someone is explicitly waiting for this txg
974 * to complete.
975 * or
976 * - the spa is shutting down because this pool is being exported
977 * or the machine is rebooting.
978 * or
979 * - the scan queue has reached its memory use limit
980 */
981 int mintime = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER) ?
982 zfs_resilver_min_time_ms : zfs_scan_min_time_ms;
983 uint64_t elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
984 int dirty_pct = scn->scn_dp->dp_dirty_total * 100 / zfs_dirty_data_max;
985 if (elapsed_nanosecs / NANOSEC >= zfs_txg_timeout ||
986 (NSEC2MSEC(elapsed_nanosecs) > mintime &&
987 (txg_sync_waiting(scn->scn_dp) ||
988 dirty_pct >= zfs_vdev_async_write_active_min_dirty_percent)) ||
989 spa_shutting_down(scn->scn_dp->dp_spa) || scn->scn_clearing ||
990 scan_io_queue_mem_lim(scn) == MEM_LIM_HARD) {
991 if (zb) {
992 DTRACE_PROBE1(scan_pause, zbookmark_phys_t *, zb);
993 dprintf("suspending at bookmark %llx/%llx/%llx/%llx\n",
994 (longlong_t)zb->zb_objset,
995 (longlong_t)zb->zb_object,
996 (longlong_t)zb->zb_level,
997 (longlong_t)zb->zb_blkid);
998 scn->scn_phys.scn_bookmark = *zb;
999 } else {
1000 DTRACE_PROBE1(scan_pause_ddt, ddt_bookmark_t *,
1001 &scn->scn_phys.scn_ddt_bookmark);
1002 dprintf("pausing at DDT bookmark %llx/%llx/%llx/%llx\n",
1003 (longlong_t)scn->scn_phys.scn_ddt_bookmark.
1004 ddb_class,
1005 (longlong_t)scn->scn_phys.scn_ddt_bookmark.
1006 ddb_type,
1007 (longlong_t)scn->scn_phys.scn_ddt_bookmark.
1008 ddb_checksum,
1009 (longlong_t)scn->scn_phys.scn_ddt_bookmark.
1010 ddb_cursor);
1011 }
1012 dprintf("suspending at DDT bookmark %llx/%llx/%llx/%llx\n",
1013 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
1014 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
1015 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
1016 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
1017 scn->scn_suspending = B_TRUE;
1018 return (B_TRUE);
1019 }
1020 return (B_FALSE);
1021 }
1022
1023 typedef struct zil_scan_arg {
1024 dsl_pool_t *zsa_dp;
1025 zil_header_t *zsa_zh;
1026 } zil_scan_arg_t;
1027
1028 /* ARGSUSED */
1029 static int
1030 dsl_scan_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
1140 * We never skip over user/group accounting objects (obj<0)
1141 */
1142 if (!ZB_IS_ZERO(&scn->scn_phys.scn_bookmark) &&
1143 (int64_t)zb->zb_object >= 0) {
1144 /*
1145 * If we already visited this bp & everything below (in
1146 * a prior txg sync), don't bother doing it again.
1147 */
1148 if (zbookmark_subtree_completed(dnp, zb,
1149 &scn->scn_phys.scn_bookmark))
1150 return (B_TRUE);
1151
1152 /*
1153 * If we found the block we're trying to resume from, or
1154 * we went past it to a different object, zero it out to
1155 * indicate that it's OK to start checking for suspending
1156 * again.
1157 */
1158 if (bcmp(zb, &scn->scn_phys.scn_bookmark, sizeof (*zb)) == 0 ||
1159 zb->zb_object > scn->scn_phys.scn_bookmark.zb_object) {
1160 DTRACE_PROBE1(scan_resume, zbookmark_phys_t *, zb);
1161 dprintf("resuming at %llx/%llx/%llx/%llx\n",
1162 (longlong_t)zb->zb_objset,
1163 (longlong_t)zb->zb_object,
1164 (longlong_t)zb->zb_level,
1165 (longlong_t)zb->zb_blkid);
1166 bzero(&scn->scn_phys.scn_bookmark, sizeof (*zb));
1167 }
1168 }
1169 return (B_FALSE);
1170 }
1171
1172 /*
1173 * Return nonzero on i/o error.
1174 * Return new buf to write out in *bufp.
1175 */
1176 static int
1177 dsl_scan_recurse(dsl_scan_t *scn, dsl_dataset_t *ds, dmu_objset_type_t ostype,
1178 dnode_phys_t *dnp, const blkptr_t *bp,
1179 const zbookmark_phys_t *zb, dmu_tx_t *tx)
1180 {
1181 dsl_pool_t *dp = scn->scn_dp;
1182 int zio_flags = ZIO_FLAG_CANFAIL | ZIO_FLAG_SCAN_THREAD;
1183 int err;
1184
1185 if (BP_GET_LEVEL(bp) > 0) {
1186 arc_flags_t flags = ARC_FLAG_WAIT;
1187 int i;
1188 blkptr_t *cbp;
1189 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
1190 arc_buf_t *buf;
1191
1192 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1193 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
1194 if (err) {
1195 atomic_inc_64(&scn->scn_phys.scn_errors);
1196 return (err);
1197 }
1198 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
1199 dsl_scan_prefetch(scn, buf, cbp, zb->zb_objset,
1200 zb->zb_object, zb->zb_blkid * epb + i);
1201 }
1202 for (i = 0, cbp = buf->b_data; i < epb; i++, cbp++) {
1203 zbookmark_phys_t czb;
1204
1205 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
1206 zb->zb_level - 1,
1207 zb->zb_blkid * epb + i);
1208 dsl_scan_visitbp(cbp, &czb, dnp,
1209 ds, scn, ostype, tx);
1210 }
1211 arc_buf_destroy(buf, &buf);
1212 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
1213 arc_flags_t flags = ARC_FLAG_WAIT;
1214 dnode_phys_t *cdnp;
1215 int i, j;
1216 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
1217 arc_buf_t *buf;
1218
1219 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1220 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
1221 if (err) {
1222 atomic_inc_64(&scn->scn_phys.scn_errors);
1223 return (err);
1224 }
1225 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
1226 for (j = 0; j < cdnp->dn_nblkptr; j++) {
1227 blkptr_t *cbp = &cdnp->dn_blkptr[j];
1228 dsl_scan_prefetch(scn, buf, cbp,
1229 zb->zb_objset, zb->zb_blkid * epb + i, j);
1230 }
1231 }
1232 for (i = 0, cdnp = buf->b_data; i < epb; i++, cdnp++) {
1233 dsl_scan_visitdnode(scn, ds, ostype,
1234 cdnp, zb->zb_blkid * epb + i, tx);
1235 }
1236
1237 arc_buf_destroy(buf, &buf);
1238 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
1239 arc_flags_t flags = ARC_FLAG_WAIT;
1240 objset_phys_t *osp;
1241 arc_buf_t *buf;
1242
1243 err = arc_read(NULL, dp->dp_spa, bp, arc_getbuf_func, &buf,
1244 ZIO_PRIORITY_ASYNC_READ, zio_flags, &flags, zb);
1245 if (err) {
1246 atomic_inc_64(&scn->scn_phys.scn_errors);
1247 return (err);
1248 }
1249
1250 osp = buf->b_data;
1251
1252 dsl_scan_visitdnode(scn, ds, osp->os_type,
1253 &osp->os_meta_dnode, DMU_META_DNODE_OBJECT, tx);
1254
1255 if (OBJSET_BUF_HAS_USERUSED(buf)) {
1256 /*
1257 * We also always visit user/group accounting
1258 * objects, and never skip them, even if we are
1259 * suspending. This is necessary so that the space
1260 * deltas from this txg get integrated.
1261 */
1262 dsl_scan_visitdnode(scn, ds, osp->os_type,
1263 &osp->os_groupused_dnode,
1264 DMU_GROUPUSED_OBJECT, tx);
1265 dsl_scan_visitdnode(scn, ds, osp->os_type,
1266 &osp->os_userused_dnode,
1306 dnode_phys_t *dnp, dsl_dataset_t *ds, dsl_scan_t *scn,
1307 dmu_objset_type_t ostype, dmu_tx_t *tx)
1308 {
1309 dsl_pool_t *dp = scn->scn_dp;
1310 arc_buf_t *buf = NULL;
1311 blkptr_t bp_toread = *bp;
1312
1313 /* ASSERT(pbuf == NULL || arc_released(pbuf)); */
1314
1315 if (dsl_scan_check_suspend(scn, zb))
1316 return;
1317
1318 if (dsl_scan_check_resume(scn, dnp, zb))
1319 return;
1320
1321 if (BP_IS_HOLE(bp))
1322 return;
1323
1324 scn->scn_visited_this_txg++;
1325
1326 #ifdef _KERNEL
1327 DTRACE_PROBE7(scan_visitbp, blkptr_t *, bp, zbookmark_phys_t *, zb,
1328 dnode_phys_t *, dnp, dsl_dataset_t *, ds, dsl_scan_t *, scn,
1329 dmu_objset_type_t, ostype, dmu_tx_t *, tx);
1330 #endif /* _KERNEL */
1331 dprintf_bp(bp,
1332 "visiting ds=%p/%llu zb=%llx/%llx/%llx/%llx bp=%p",
1333 ds, ds ? ds->ds_object : 0,
1334 zb->zb_objset, zb->zb_object, zb->zb_level, zb->zb_blkid,
1335 bp);
1336
1337 if (bp->blk_birth <= scn->scn_phys.scn_cur_min_txg)
1338 return;
1339
1340 if (dsl_scan_recurse(scn, ds, ostype, dnp, &bp_toread, zb, tx) != 0)
1341 return;
1342
1343 /*
1344 * If dsl_scan_ddt() has already visited this block, it will have
1345 * already done any translations or scrubbing, so don't call the
1346 * callback again.
1347 */
1348 if (ddt_class_contains(dp->dp_spa,
1349 scn->scn_phys.scn_ddt_class_max, bp)) {
1350 ASSERT(buf == NULL);
1357 * revisit the future block on the next pass of this dataset.
1358 * Don't scan it now unless we need to because something
1359 * under it was modified.
1360 */
1361 if (BP_PHYSICAL_BIRTH(bp) <= scn->scn_phys.scn_cur_max_txg) {
1362 scan_funcs[scn->scn_phys.scn_func](dp, bp, zb);
1363 }
1364 }
1365
1366 static void
1367 dsl_scan_visit_rootbp(dsl_scan_t *scn, dsl_dataset_t *ds, blkptr_t *bp,
1368 dmu_tx_t *tx)
1369 {
1370 zbookmark_phys_t zb;
1371
1372 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
1373 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
1374 dsl_scan_visitbp(bp, &zb, NULL,
1375 ds, scn, DMU_OST_NONE, tx);
1376
1377 DTRACE_PROBE4(scan_finished, dsl_scan_t *, scn, dsl_dataset_t *, ds,
1378 blkptr_t *, bp, dmu_tx_t *, tx);
1379 dprintf_ds(ds, "finished scan%s", "");
1380 }
1381
1382 static void
1383 ds_destroyed_scn_phys(dsl_dataset_t *ds, dsl_scan_phys_t *scn_phys)
1384 {
1385 if (scn_phys->scn_bookmark.zb_objset == ds->ds_object) {
1386 if (ds->ds_is_snapshot) {
1387 /*
1388 * Note:
1389 * - scn_cur_{min,max}_txg stays the same.
1390 * - Setting the flag is not really necessary if
1391 * scn_cur_max_txg == scn_max_txg, because there
1392 * is nothing after this snapshot that we care
1393 * about. However, we set it anyway and then
1394 * ignore it when we retraverse it in
1395 * dsl_scan_visitds().
1396 */
1397 scn_phys->scn_bookmark.zb_objset =
1398 dsl_dataset_phys(ds)->ds_next_snap_obj;
1399 zfs_dbgmsg("destroying ds %llu; currently traversing; "
1400 "reset zb_objset to %llu",
1401 (u_longlong_t)ds->ds_object,
1402 (u_longlong_t)dsl_dataset_phys(ds)->
1403 ds_next_snap_obj);
1404 scn_phys->scn_flags |= DSF_VISIT_DS_AGAIN;
1405 } else {
1406 SET_BOOKMARK(&scn_phys->scn_bookmark,
1407 ZB_DESTROYED_OBJSET, 0, 0, 0);
1408 zfs_dbgmsg("destroying ds %llu; currently traversing; "
1409 "reset bookmark to -1,0,0,0",
1410 (u_longlong_t)ds->ds_object);
1411 }
1412 }
1413 }
1414
1415 /*
1416 * Invoked when a dataset is destroyed. We need to make sure that:
1417 *
1418 * 1) If it is the dataset that was currently being scanned, we write
1419 * a new dsl_scan_phys_t and marking the objset reference in it
1420 * as destroyed.
1421 * 2) Remove it from the work queue, if it was present.
1422 *
1423 * If the dataset was actually a snapshot, instead of marking the dataset
1424 * as destroyed, we instead substitute the next snapshot in line.
1425 */
1426 void
1427 dsl_scan_ds_destroyed(dsl_dataset_t *ds, dmu_tx_t *tx)
1428 {
1429 dsl_pool_t *dp = ds->ds_dir->dd_pool;
1430 dsl_scan_t *scn = dp->dp_scan;
1431 uint64_t mintxg;
1432
1433 if (!dsl_scan_is_running(scn))
1434 return;
1435
1436 ds_destroyed_scn_phys(ds, &scn->scn_phys);
1437 ds_destroyed_scn_phys(ds, &scn->scn_phys_cached);
1438
1439 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
1440 scan_ds_queue_remove(scn, ds->ds_object);
1441 if (ds->ds_is_snapshot) {
1442 VERIFY0(scan_ds_queue_insert(scn,
1443 dsl_dataset_phys(ds)->ds_next_snap_obj, mintxg));
1444 }
1445 }
1446
1447 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1448 ds->ds_object, &mintxg) == 0) {
1449 DTRACE_PROBE3(scan_ds_destroyed__in_queue,
1450 dsl_scan_t *, scn, dsl_dataset_t *, ds, dmu_tx_t *, tx);
1451 ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
1452 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1453 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
1454 if (ds->ds_is_snapshot) {
1455 /*
1456 * We keep the same mintxg; it could be >
1457 * ds_creation_txg if the previous snapshot was
1458 * deleted too.
1459 */
1460 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1461 scn->scn_phys.scn_queue_obj,
1462 dsl_dataset_phys(ds)->ds_next_snap_obj,
1463 mintxg, tx) == 0);
1464 zfs_dbgmsg("destroying ds %llu; in queue; "
1465 "replacing with %llu",
1466 (u_longlong_t)ds->ds_object,
1467 (u_longlong_t)dsl_dataset_phys(ds)->
1468 ds_next_snap_obj);
1469 } else {
1470 zfs_dbgmsg("destroying ds %llu; in queue; removing",
1471 (u_longlong_t)ds->ds_object);
1472 }
1473 }
1474
1475 /*
1476 * dsl_scan_sync() should be called after this, and should sync
1477 * out our changed state, but just to be safe, do it here.
1478 */
1479 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
1480 }
1481
1482 static void
1483 ds_snapshotted_bookmark(dsl_dataset_t *ds, zbookmark_phys_t *scn_bookmark)
1484 {
1485 if (scn_bookmark->zb_objset == ds->ds_object) {
1486 scn_bookmark->zb_objset =
1487 dsl_dataset_phys(ds)->ds_prev_snap_obj;
1488 zfs_dbgmsg("snapshotting ds %llu; currently traversing; "
1489 "reset zb_objset to %llu",
1490 (u_longlong_t)ds->ds_object,
1491 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
1492 }
1493 }
1494
1495 /*
1496 * Called when a dataset is snapshotted. If we were currently traversing
1497 * this snapshot, we reset our bookmark to point at the newly created
1498 * snapshot. We also modify our work queue to remove the old snapshot and
1499 * replace with the new one.
1500 */
1501 void
1502 dsl_scan_ds_snapshotted(dsl_dataset_t *ds, dmu_tx_t *tx)
1503 {
1504 dsl_pool_t *dp = ds->ds_dir->dd_pool;
1505 dsl_scan_t *scn = dp->dp_scan;
1506 uint64_t mintxg;
1507
1508 if (!dsl_scan_is_running(scn))
1509 return;
1510
1511 ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
1512
1513 ds_snapshotted_bookmark(ds, &scn->scn_phys.scn_bookmark);
1514 ds_snapshotted_bookmark(ds, &scn->scn_phys_cached.scn_bookmark);
1515
1516 if (scan_ds_queue_contains(scn, ds->ds_object, &mintxg)) {
1517 scan_ds_queue_remove(scn, ds->ds_object);
1518 VERIFY0(scan_ds_queue_insert(scn,
1519 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg));
1520 }
1521
1522 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1523 ds->ds_object, &mintxg) == 0) {
1524 DTRACE_PROBE3(scan_ds_snapshotted__in_queue,
1525 dsl_scan_t *, scn, dsl_dataset_t *, ds, dmu_tx_t *, tx);
1526
1527 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1528 scn->scn_phys.scn_queue_obj, ds->ds_object, tx));
1529 VERIFY(zap_add_int_key(dp->dp_meta_objset,
1530 scn->scn_phys.scn_queue_obj,
1531 dsl_dataset_phys(ds)->ds_prev_snap_obj, mintxg, tx) == 0);
1532 zfs_dbgmsg("snapshotting ds %llu; in queue; "
1533 "replacing with %llu",
1534 (u_longlong_t)ds->ds_object,
1535 (u_longlong_t)dsl_dataset_phys(ds)->ds_prev_snap_obj);
1536 }
1537
1538 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
1539 }
1540
1541 static void
1542 ds_clone_swapped_bookmark(dsl_dataset_t *ds1, dsl_dataset_t *ds2,
1543 zbookmark_phys_t *scn_bookmark)
1544 {
1545 if (scn_bookmark->zb_objset == ds1->ds_object) {
1546 scn_bookmark->zb_objset = ds2->ds_object;
1547 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
1548 "reset zb_objset to %llu",
1549 (u_longlong_t)ds1->ds_object,
1550 (u_longlong_t)ds2->ds_object);
1551 } else if (scn_bookmark->zb_objset == ds2->ds_object) {
1552 scn_bookmark->zb_objset = ds1->ds_object;
1553 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
1554 "reset zb_objset to %llu",
1555 (u_longlong_t)ds2->ds_object,
1556 (u_longlong_t)ds1->ds_object);
1557 }
1558 }
1559
1560 /*
1561 * Called when a parent dataset and its clone are swapped. If we were
1562 * currently traversing the dataset, we need to switch to traversing the
1563 * newly promoted parent.
1564 */
1565 void
1566 dsl_scan_ds_clone_swapped(dsl_dataset_t *ds1, dsl_dataset_t *ds2, dmu_tx_t *tx)
1567 {
1568 dsl_pool_t *dp = ds1->ds_dir->dd_pool;
1569 dsl_scan_t *scn = dp->dp_scan;
1570 uint64_t mintxg;
1571
1572 if (!dsl_scan_is_running(scn))
1573 return;
1574
1575 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys.scn_bookmark);
1576 ds_clone_swapped_bookmark(ds1, ds2, &scn->scn_phys_cached.scn_bookmark);
1577
1578 if (scan_ds_queue_contains(scn, ds1->ds_object, &mintxg)) {
1579 int err;
1580
1581 scan_ds_queue_remove(scn, ds1->ds_object);
1582 err = scan_ds_queue_insert(scn, ds2->ds_object, mintxg);
1583 VERIFY(err == 0 || err == EEXIST);
1584 if (err == EEXIST) {
1585 /* Both were there to begin with */
1586 VERIFY0(scan_ds_queue_insert(scn, ds1->ds_object,
1587 mintxg));
1588 }
1589 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
1590 "reset zb_objset to %llu",
1591 (u_longlong_t)ds1->ds_object,
1592 (u_longlong_t)ds2->ds_object);
1593 } else if (scan_ds_queue_contains(scn, ds2->ds_object, &mintxg)) {
1594 scan_ds_queue_remove(scn, ds2->ds_object);
1595 VERIFY0(scan_ds_queue_insert(scn, ds1->ds_object, mintxg));
1596 zfs_dbgmsg("clone_swap ds %llu; currently traversing; "
1597 "reset zb_objset to %llu",
1598 (u_longlong_t)ds2->ds_object,
1599 (u_longlong_t)ds1->ds_object);
1600 }
1601
1602 if (zap_lookup_int_key(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj,
1603 ds1->ds_object, &mintxg) == 0) {
1604 int err;
1605
1606 DTRACE_PROBE4(scan_ds_clone_swapped__in_queue_ds1,
1607 dsl_scan_t *, scn, dsl_dataset_t *, ds1,
1608 dsl_dataset_t *, ds2, dmu_tx_t *, tx);
1609 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
1610 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
1611 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1612 scn->scn_phys.scn_queue_obj, ds1->ds_object, tx));
1613 err = zap_add_int_key(dp->dp_meta_objset,
1614 scn->scn_phys.scn_queue_obj, ds2->ds_object, mintxg, tx);
1615 VERIFY(err == 0 || err == EEXIST);
1616 if (err == EEXIST) {
1617 /* Both were there to begin with */
1618 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
1619 scn->scn_phys.scn_queue_obj,
1620 ds1->ds_object, mintxg, tx));
1621 }
1622 zfs_dbgmsg("clone_swap ds %llu; in queue; "
1623 "replacing with %llu",
1624 (u_longlong_t)ds1->ds_object,
1625 (u_longlong_t)ds2->ds_object);
1626 } else if (zap_lookup_int_key(dp->dp_meta_objset,
1627 scn->scn_phys.scn_queue_obj, ds2->ds_object, &mintxg) == 0) {
1628 DTRACE_PROBE4(scan_ds_clone_swapped__in_queue_ds2,
1629 dsl_scan_t *, scn, dsl_dataset_t *, ds1,
1630 dsl_dataset_t *, ds2, dmu_tx_t *, tx);
1631 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds1)->ds_prev_snap_txg);
1632 ASSERT3U(mintxg, ==, dsl_dataset_phys(ds2)->ds_prev_snap_txg);
1633 VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset,
1634 scn->scn_phys.scn_queue_obj, ds2->ds_object, tx));
1635 VERIFY(0 == zap_add_int_key(dp->dp_meta_objset,
1636 scn->scn_phys.scn_queue_obj, ds1->ds_object, mintxg, tx));
1637 zfs_dbgmsg("clone_swap ds %llu; in queue; "
1638 "replacing with %llu",
1639 (u_longlong_t)ds2->ds_object,
1640 (u_longlong_t)ds1->ds_object);
1641 }
1642
1643 dsl_scan_sync_state(scn, tx, SYNC_CACHED);
1644 }
1645
1646 /* ARGSUSED */
1647 static int
1648 enqueue_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1649 {
1650 uint64_t originobj = *(uint64_t *)arg;
1651 dsl_dataset_t *ds;
1652 int err;
1653 dsl_scan_t *scn = dp->dp_scan;
1654
1655 if (dsl_dir_phys(hds->ds_dir)->dd_origin_obj != originobj)
1656 return (0);
1657
1658 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1659 if (err)
1660 return (err);
1661
1662 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != originobj) {
1663 dsl_dataset_t *prev;
1664 err = dsl_dataset_hold_obj(dp,
1665 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1666
1667 dsl_dataset_rele(ds, FTAG);
1668 if (err)
1669 return (err);
1670 ds = prev;
1671 }
1672 VERIFY0(scan_ds_queue_insert(scn, ds->ds_object,
1673 dsl_dataset_phys(ds)->ds_prev_snap_txg));
1674 dsl_dataset_rele(ds, FTAG);
1675 return (0);
1676 }
1677
1678 static void
1679 dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
1680 {
1681 dsl_pool_t *dp = scn->scn_dp;
1682 dsl_dataset_t *ds;
1683 objset_t *os;
1684
1685 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1686
1687 if (scn->scn_phys.scn_cur_min_txg >=
1688 scn->scn_phys.scn_max_txg) {
1689 /*
1690 * This can happen if this snapshot was created after the
1691 * scan started, and we already completed a previous snapshot
1692 * that was created after the scan started. This snapshot
1693 * only references blocks with:
1694 *
1695 * birth < our ds_creation_txg
1696 * cur_min_txg is no less than ds_creation_txg.
1697 * We have already visited these blocks.
1698 * or
1699 * birth > scn_max_txg
1700 * The scan requested not to visit these blocks.
1701 *
1702 * Subsequent snapshots (and clones) can reference our
1703 * blocks, or blocks with even higher birth times.
1707 * Note that checking for cur_min_txg >= cur_max_txg
1708 * is not sufficient, because in that case we may need to
1709 * visit subsequent snapshots. This happens when min_txg > 0,
1710 * which raises cur_min_txg. In this case we will visit
1711 * this dataset but skip all of its blocks, because the
1712 * rootbp's birth time is < cur_min_txg. Then we will
1713 * add the next snapshots/clones to the work queue.
1714 */
1715 char *dsname = kmem_alloc(MAXNAMELEN, KM_SLEEP);
1716 dsl_dataset_name(ds, dsname);
1717 zfs_dbgmsg("scanning dataset %llu (%s) is unnecessary because "
1718 "cur_min_txg (%llu) >= max_txg (%llu)",
1719 dsobj, dsname,
1720 scn->scn_phys.scn_cur_min_txg,
1721 scn->scn_phys.scn_max_txg);
1722 kmem_free(dsname, MAXNAMELEN);
1723
1724 goto out;
1725 }
1726
1727 if (dmu_objset_from_ds(ds, &os))
1728 goto out;
1729
1730 /*
1731 * Only the ZIL in the head (non-snapshot) is valid. Even though
1732 * snapshots can have ZIL block pointers (which may be the same
1733 * BP as in the head), they must be ignored. So we traverse the
1734 * ZIL here, rather than in scan_recurse(), because the regular
1735 * snapshot block-sharing rules don't apply to it.
1736 */
1737 if (DSL_SCAN_IS_SCRUB_RESILVER(scn) && !ds->ds_is_snapshot)
1738 dsl_scan_zil(dp, &os->os_zil_header);
1739
1740 /*
1741 * Iterate over the bps in this ds.
1742 */
1743 dmu_buf_will_dirty(ds->ds_dbuf, tx);
1744 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1745 dsl_scan_visit_rootbp(scn, ds, &dsl_dataset_phys(ds)->ds_bp, tx);
1746 rrw_exit(&ds->ds_bp_rwlock, FTAG);
1747
1748 char *dsname = kmem_alloc(ZFS_MAX_DATASET_NAME_LEN, KM_SLEEP);
1749 dsl_dataset_name(ds, dsname);
1750 zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
1751 "suspending=%u",
1752 (longlong_t)dsobj, dsname,
1753 (longlong_t)scn->scn_phys.scn_cur_min_txg,
1754 (longlong_t)scn->scn_phys.scn_cur_max_txg,
1755 (int)scn->scn_suspending);
1756 kmem_free(dsname, ZFS_MAX_DATASET_NAME_LEN);
1757
1758 DTRACE_PROBE3(scan_done, dsl_scan_t *, scn, dsl_dataset_t *, ds,
1759 dmu_tx_t *, tx);
1760
1761 if (scn->scn_suspending)
1762 goto out;
1763
1764 /*
1765 * We've finished this pass over this dataset.
1766 */
1767
1768 /*
1769 * If we did not completely visit this dataset, do another pass.
1770 */
1771 if (scn->scn_phys.scn_flags & DSF_VISIT_DS_AGAIN) {
1772 DTRACE_PROBE3(scan_incomplete, dsl_scan_t *, scn,
1773 dsl_dataset_t *, ds, dmu_tx_t *, tx);
1774 zfs_dbgmsg("incomplete pass; visiting again");
1775 scn->scn_phys.scn_flags &= ~DSF_VISIT_DS_AGAIN;
1776 VERIFY0(scan_ds_queue_insert(scn, ds->ds_object,
1777 scn->scn_phys.scn_cur_max_txg));
1778 goto out;
1779 }
1780
1781 /*
1782 * Add descendent datasets to work queue.
1783 */
1784 if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
1785 VERIFY0(scan_ds_queue_insert(scn,
1786 dsl_dataset_phys(ds)->ds_next_snap_obj,
1787 dsl_dataset_phys(ds)->ds_creation_txg));
1788 }
1789 if (dsl_dataset_phys(ds)->ds_num_children > 1) {
1790 boolean_t usenext = B_FALSE;
1791 if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
1792 uint64_t count;
1793 /*
1794 * A bug in a previous version of the code could
1795 * cause upgrade_clones_cb() to not set
1796 * ds_next_snap_obj when it should, leading to a
1797 * missing entry. Therefore we can only use the
1798 * next_clones_obj when its count is correct.
1799 */
1800 int err = zap_count(dp->dp_meta_objset,
1801 dsl_dataset_phys(ds)->ds_next_clones_obj, &count);
1802 if (err == 0 &&
1803 count == dsl_dataset_phys(ds)->ds_num_children - 1)
1804 usenext = B_TRUE;
1805 }
1806
1807 if (usenext) {
1808 zap_cursor_t zc;
1809 zap_attribute_t za;
1810 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1811 dsl_dataset_phys(ds)->ds_next_clones_obj);
1812 zap_cursor_retrieve(&zc, &za) == 0;
1813 (void) zap_cursor_advance(&zc)) {
1814 VERIFY0(scan_ds_queue_insert(scn,
1815 zfs_strtonum(za.za_name, NULL),
1816 dsl_dataset_phys(ds)->ds_creation_txg));
1817 }
1818 zap_cursor_fini(&zc);
1819 } else {
1820 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1821 enqueue_clones_cb, &ds->ds_object,
1822 DS_FIND_CHILDREN));
1823 }
1824 }
1825
1826 out:
1827 dsl_dataset_rele(ds, FTAG);
1828 }
1829
1830 /* ARGSUSED */
1831 static int
1832 enqueue_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
1833 {
1834 dsl_dataset_t *ds;
1835 int err;
1836 dsl_scan_t *scn = dp->dp_scan;
1837
1838 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
1839 if (err)
1840 return (err);
1841
1842 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1843 dsl_dataset_t *prev;
1844 err = dsl_dataset_hold_obj(dp,
1845 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1846 if (err) {
1847 dsl_dataset_rele(ds, FTAG);
1848 return (err);
1849 }
1850
1851 /*
1852 * If this is a clone, we don't need to worry about it for now.
1853 */
1854 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object) {
1855 dsl_dataset_rele(ds, FTAG);
1856 dsl_dataset_rele(prev, FTAG);
1857 return (0);
1858 }
1859 dsl_dataset_rele(ds, FTAG);
1860 ds = prev;
1861 }
1862
1863 VERIFY0(scan_ds_queue_insert(scn, ds->ds_object,
1864 dsl_dataset_phys(ds)->ds_prev_snap_txg));
1865 dsl_dataset_rele(ds, FTAG);
1866 return (0);
1867 }
1868
1869 /*
1870 * Scrub/dedup interaction.
1871 *
1872 * If there are N references to a deduped block, we don't want to scrub it
1873 * N times -- ideally, we should scrub it exactly once.
1874 *
1875 * We leverage the fact that the dde's replication class (enum ddt_class)
1876 * is ordered from highest replication class (DDT_CLASS_DITTO) to lowest
1877 * (DDT_CLASS_UNIQUE) so that we may walk the DDT in that order.
1878 *
1879 * To prevent excess scrubbing, the scrub begins by walking the DDT
1880 * to find all blocks with refcnt > 1, and scrubs each of these once.
1881 * Since there are two replication classes which contain blocks with
1882 * refcnt > 1, we scrub the highest replication class (DDT_CLASS_DITTO) first.
1883 * Finally the top-down scrub begins, only visiting blocks with refcnt == 1.
1884 *
1895 * If a block has refcnt == 1 during the DDT scrub phase, but has refcnt > 1
1896 * on each visit during the top-down scrub phase, it will never be scrubbed.
1897 * To catch this, ddt_sync_entry() notifies the scrub code whenever a block's
1898 * reference class transitions to a higher level (i.e DDT_CLASS_UNIQUE to
1899 * DDT_CLASS_DUPLICATE); if it transitions from refcnt == 1 to refcnt > 1
1900 * while a scrub is in progress, it scrubs the block right then.
1901 */
1902 static void
1903 dsl_scan_ddt(dsl_scan_t *scn, dmu_tx_t *tx)
1904 {
1905 ddt_bookmark_t *ddb = &scn->scn_phys.scn_ddt_bookmark;
1906 ddt_entry_t dde = { 0 };
1907 int error;
1908 uint64_t n = 0;
1909
1910 while ((error = ddt_walk(scn->scn_dp->dp_spa, ddb, &dde)) == 0) {
1911 ddt_t *ddt;
1912
1913 if (ddb->ddb_class > scn->scn_phys.scn_ddt_class_max)
1914 break;
1915 DTRACE_PROBE1(scan_ddb, ddt_bookmark_t *, ddb);
1916 dprintf("visiting ddb=%llu/%llu/%llu/%llx\n",
1917 (longlong_t)ddb->ddb_class,
1918 (longlong_t)ddb->ddb_type,
1919 (longlong_t)ddb->ddb_checksum,
1920 (longlong_t)ddb->ddb_cursor);
1921
1922 /* There should be no pending changes to the dedup table */
1923 ddt = scn->scn_dp->dp_spa->spa_ddt[ddb->ddb_checksum];
1924 #ifdef ZFS_DEBUG
1925 for (uint_t i = 0; i < DDT_HASHSZ; i++)
1926 ASSERT(avl_first(&ddt->ddt_tree[i]) == NULL);
1927 #endif
1928 dsl_scan_ddt_entry(scn, ddb->ddb_checksum, &dde, tx);
1929 n++;
1930
1931 if (dsl_scan_check_suspend(scn, NULL))
1932 break;
1933 }
1934
1935 DTRACE_PROBE2(scan_ddt_done, dsl_scan_t *, scn, uint64_t, n);
1936 zfs_dbgmsg("scanned %llu ddt entries with class_max = %u; "
1937 "suspending=%u", (longlong_t)n,
1938 (int)scn->scn_phys.scn_ddt_class_max, (int)scn->scn_suspending);
1939
1940 ASSERT(error == 0 || error == ENOENT);
1941 ASSERT(error != ENOENT ||
1942 ddb->ddb_class > scn->scn_phys.scn_ddt_class_max);
1943 }
1944
1945 /* ARGSUSED */
1946 void
1947 dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
1948 ddt_entry_t *dde, dmu_tx_t *tx)
1949 {
1950 const ddt_key_t *ddk = &dde->dde_key;
1951 ddt_phys_t *ddp = dde->dde_phys;
1952 blkptr_t bp;
1953 zbookmark_phys_t zb = { 0 };
1954
1955 if (scn->scn_phys.scn_state != DSS_SCANNING)
1956 return;
1957
1958 for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
1959 if (ddp->ddp_phys_birth == 0 ||
1960 ddp->ddp_phys_birth > scn->scn_phys.scn_max_txg)
1961 continue;
1962 ddt_bp_create(checksum, ddk, ddp, &bp);
1963
1964 scn->scn_visited_this_txg++;
1965 scan_funcs[scn->scn_phys.scn_func](scn->scn_dp, &bp, &zb);
1966 }
1967 }
1968
1969 static void
1970 dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx)
1971 {
1972 dsl_pool_t *dp = scn->scn_dp;
1973 uint64_t dsobj, txg;
1974
1975 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
1976 scn->scn_phys.scn_ddt_class_max) {
1977 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1978 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1979 dsl_scan_ddt(scn, tx);
1980 if (scn->scn_suspending)
1981 return;
1982 }
1983
1984 if (scn->scn_phys.scn_bookmark.zb_objset == DMU_META_OBJSET) {
1985 /* First do the MOS & ORIGIN */
1986
1987 scn->scn_phys.scn_cur_min_txg = scn->scn_phys.scn_min_txg;
1988 scn->scn_phys.scn_cur_max_txg = scn->scn_phys.scn_max_txg;
1989 dsl_scan_visit_rootbp(scn, NULL,
1990 &dp->dp_meta_rootbp, tx);
1991 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
1992 if (scn->scn_suspending)
1993 return;
1994
1995 if (spa_version(dp->dp_spa) < SPA_VERSION_DSL_SCRUB) {
1996 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
1997 enqueue_cb, NULL, DS_FIND_CHILDREN));
1998 } else {
1999 dsl_scan_visitds(scn,
2000 dp->dp_origin_snap->ds_object, tx);
2001 }
2002 ASSERT(!scn->scn_suspending);
2003 } else if (scn->scn_phys.scn_bookmark.zb_objset !=
2004 ZB_DESTROYED_OBJSET) {
2005 uint64_t dsobj = scn->scn_phys.scn_bookmark.zb_objset;
2006 /*
2007 * If we were suspended, continue from here. Note if the
2008 * ds we were suspended on was deleted, the zb_objset may
2009 * be -1, so we will skip this and find a new objset
2010 * below.
2011 */
2012 dsl_scan_visitds(scn, dsobj, tx);
2013 if (scn->scn_suspending)
2014 return;
2015 }
2016
2017 /*
2018 * In case we were suspended right at the end of the ds, zero the
2019 * bookmark so we don't think that we're still trying to resume.
2020 */
2021 bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_phys_t));
2022
2023 /* keep pulling things out of the zap-object-as-queue */
2024 while (scan_ds_queue_first(scn, &dsobj, &txg)) {
2025 dsl_dataset_t *ds;
2026
2027 scan_ds_queue_remove(scn, dsobj);
2028
2029 /* Set up min/max txg */
2030 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
2031 if (txg != 0) {
2032 scn->scn_phys.scn_cur_min_txg =
2033 MAX(scn->scn_phys.scn_min_txg, txg);
2034 } else {
2035 scn->scn_phys.scn_cur_min_txg =
2036 MAX(scn->scn_phys.scn_min_txg,
2037 dsl_dataset_phys(ds)->ds_prev_snap_txg);
2038 }
2039 scn->scn_phys.scn_cur_max_txg = dsl_scan_ds_maxtxg(ds);
2040 dsl_dataset_rele(ds, FTAG);
2041
2042 dsl_scan_visitds(scn, dsobj, tx);
2043 if (scn->scn_suspending)
2044 return;
2045 }
2046 /* No more objsets to fetch, we're done */
2047 scn->scn_phys.scn_bookmark.zb_objset = ZB_DESTROYED_OBJSET;
2048 ASSERT0(scn->scn_suspending);
2049 }
2050
2051 static boolean_t
2052 dsl_scan_free_should_suspend(dsl_scan_t *scn)
2053 {
2054 uint64_t elapsed_nanosecs;
2055
2056 if (zfs_recover)
2057 return (B_FALSE);
2058
2059 if (scn->scn_visited_this_txg >= zfs_free_max_blocks)
2060 return (B_TRUE);
2061
2062 elapsed_nanosecs = gethrtime() - scn->scn_sync_start_time;
2063 return (elapsed_nanosecs / NANOSEC > zfs_txg_timeout ||
2064 (NSEC2MSEC(elapsed_nanosecs) > zfs_free_min_time_ms &&
2065 txg_sync_waiting(scn->scn_dp)) ||
2066 spa_shutting_down(scn->scn_dp->dp_spa));
2067 }
2068
2069 static int
2070 dsl_scan_free_block_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
2071 {
2072 dsl_scan_t *scn = arg;
2073
2074 if (!scn->scn_is_bptree ||
2075 (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_OBJSET)) {
2076 if (dsl_scan_free_should_suspend(scn))
2077 return (SET_ERROR(ERESTART));
2078 }
2079
2080 zio_nowait(zio_free_sync(scn->scn_zio_root, scn->scn_dp->dp_spa,
2081 dmu_tx_get_txg(tx), bp, 0));
2082 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir, DD_USED_HEAD,
2083 -bp_get_dsize_sync(scn->scn_dp->dp_spa, bp),
2084 -BP_GET_PSIZE(bp), -BP_GET_UCSIZE(bp), tx);
2085 scn->scn_visited_this_txg++;
2086 return (0);
2087 }
2088
2089 boolean_t
2090 dsl_scan_active(dsl_scan_t *scn)
2091 {
2092 spa_t *spa = scn->scn_dp->dp_spa;
2093 uint64_t used = 0, comp, uncomp;
2094
2095 if (spa->spa_load_state != SPA_LOAD_NONE)
2096 return (B_FALSE);
2097 if (spa_shutting_down(spa))
2098 return (B_FALSE);
2099 if ((dsl_scan_is_running(scn) && !dsl_scan_is_paused_scrub(scn)) ||
2100 (scn->scn_async_destroying && !scn->scn_async_stalled))
2101 return (B_TRUE);
2102
2103 if (spa_version(scn->scn_dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
2104 (void) bpobj_space(&scn->scn_dp->dp_free_bpobj,
2105 &used, &comp, &uncomp);
2106 }
2107 return (used != 0);
2108 }
2109
2110 /* Called whenever a txg syncs. */
2111 void
2112 dsl_scan_sync(dsl_pool_t *dp, dmu_tx_t *tx)
2113 {
2114 dsl_scan_t *scn = dp->dp_scan;
2115 spa_t *spa = dp->dp_spa;
2116 int err = 0;
2117
2118 /*
2119 * Check for scn_restart_txg before checking spa_load_state, so
2148 * If the scan is inactive due to a stalled async destroy, try again.
2149 */
2150 if (!scn->scn_async_stalled && !dsl_scan_active(scn))
2151 return;
2152
2153 scn->scn_visited_this_txg = 0;
2154 scn->scn_suspending = B_FALSE;
2155 scn->scn_sync_start_time = gethrtime();
2156 spa->spa_scrub_active = B_TRUE;
2157
2158 /*
2159 * First process the async destroys. If we suspend, don't do
2160 * any scrubbing or resilvering. This ensures that there are no
2161 * async destroys while we are scanning, so the scan code doesn't
2162 * have to worry about traversing it. It is also faster to free the
2163 * blocks than to scrub them.
2164 */
2165 if (zfs_free_bpobj_enabled &&
2166 spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
2167 scn->scn_is_bptree = B_FALSE;
2168 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
2169 NULL, ZIO_FLAG_MUSTSUCCEED);
2170 err = bpobj_iterate(&dp->dp_free_bpobj,
2171 dsl_scan_free_block_cb, scn, tx);
2172 VERIFY3U(0, ==, zio_wait(scn->scn_zio_root));
2173
2174 if (err != 0 && err != ERESTART)
2175 zfs_panic_recover("error %u from bpobj_iterate()", err);
2176 }
2177
2178 if (err == 0 && spa_feature_is_active(spa, SPA_FEATURE_ASYNC_DESTROY)) {
2179 ASSERT(scn->scn_async_destroying);
2180 scn->scn_is_bptree = B_TRUE;
2181 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
2182 NULL, ZIO_FLAG_MUSTSUCCEED);
2183 err = bptree_iterate(dp->dp_meta_objset,
2184 dp->dp_bptree_obj, B_TRUE, dsl_scan_free_block_cb, scn, tx);
2185 VERIFY0(zio_wait(scn->scn_zio_root));
2186
2187 if (err == EIO || err == ECKSUM) {
2245 * some space left in the dp_free_dir. Transfer this leaked
2246 * space to the dp_leak_dir.
2247 */
2248 if (dp->dp_leak_dir == NULL) {
2249 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
2250 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
2251 LEAK_DIR_NAME, tx);
2252 VERIFY0(dsl_pool_open_special_dir(dp,
2253 LEAK_DIR_NAME, &dp->dp_leak_dir));
2254 rrw_exit(&dp->dp_config_rwlock, FTAG);
2255 }
2256 dsl_dir_diduse_space(dp->dp_leak_dir, DD_USED_HEAD,
2257 dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
2258 dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
2259 dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
2260 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
2261 -dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes,
2262 -dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes,
2263 -dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes, tx);
2264 }
2265 if (dp->dp_free_dir != NULL && !scn->scn_async_destroying) {
2266 /* finished; verify that space accounting went to zero */
2267 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_used_bytes);
2268 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_compressed_bytes);
2269 ASSERT0(dsl_dir_phys(dp->dp_free_dir)->dd_uncompressed_bytes);
2270 }
2271
2272 if (!dsl_scan_is_running(scn))
2273 return;
2274
2275 if (!zfs_scan_direct) {
2276 if (!scn->scn_is_sorted)
2277 scn->scn_last_queue_run_time = 0;
2278 scn->scn_is_sorted = B_TRUE;
2279 }
2280
2281 if (scn->scn_done_txg == tx->tx_txg ||
2282 scn->scn_phys.scn_state == DSS_FINISHING) {
2283 ASSERT(!scn->scn_suspending);
2284 if (scn->scn_bytes_pending != 0) {
2285 ASSERT(scn->scn_is_sorted);
2286 scn->scn_phys.scn_state = DSS_FINISHING;
2287 goto finish;
2288 }
2289 /* finished with scan. */
2290 zfs_dbgmsg("txg %llu scan complete", tx->tx_txg);
2291 dsl_scan_done(scn, B_TRUE, tx);
2292 ASSERT3U(spa->spa_scrub_inflight, ==, 0);
2293 dsl_scan_sync_state(scn, tx, SYNC_MANDATORY);
2294 return;
2295 }
2296
2297 if (dsl_scan_is_paused_scrub(scn))
2298 return;
2299
2300 if (scn->scn_phys.scn_ddt_bookmark.ddb_class <=
2301 scn->scn_phys.scn_ddt_class_max) {
2302 zfs_dbgmsg("doing scan sync txg %llu; "
2303 "ddt bm=%llu/%llu/%llu/%llx",
2304 (longlong_t)tx->tx_txg,
2305 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_class,
2306 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_type,
2307 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_checksum,
2308 (longlong_t)scn->scn_phys.scn_ddt_bookmark.ddb_cursor);
2309 ASSERT(scn->scn_phys.scn_bookmark.zb_objset == 0);
2310 ASSERT(scn->scn_phys.scn_bookmark.zb_object == 0);
2311 ASSERT(scn->scn_phys.scn_bookmark.zb_level == 0);
2312 ASSERT(scn->scn_phys.scn_bookmark.zb_blkid == 0);
2313 } else {
2314 zfs_dbgmsg("doing scan sync txg %llu; bm=%llu/%llu/%llu/%llu",
2315 (longlong_t)tx->tx_txg,
2316 (longlong_t)scn->scn_phys.scn_bookmark.zb_objset,
2317 (longlong_t)scn->scn_phys.scn_bookmark.zb_object,
2318 (longlong_t)scn->scn_phys.scn_bookmark.zb_level,
2319 (longlong_t)scn->scn_phys.scn_bookmark.zb_blkid);
2320 }
2321
2322 if (scn->scn_is_sorted) {
2323 /*
2324 * This is the out-of-order queue handling. We determine our
2325 * memory usage and based on that switch states between normal
2326 * operation (i.e. don't issue queued up I/O unless we've
2327 * reached the end of scanning) and 'clearing' (issue queued
2328 * extents just to clear up some memory).
2329 */
2330 mem_lim_t mlim = scan_io_queue_mem_lim(scn);
2331
2332 if (mlim == MEM_LIM_HARD && !scn->scn_clearing)
2333 scn->scn_clearing = B_TRUE;
2334 else if (mlim == MEM_LIM_NONE && scn->scn_clearing)
2335 scn->scn_clearing = B_FALSE;
2336
2337 if ((scn->scn_checkpointing || ddi_get_lbolt() -
2338 scn->scn_last_checkpoint > ZFS_SCAN_CHECKPOINT_INTVAL) &&
2339 scn->scn_phys.scn_state != DSS_FINISHING &&
2340 !scn->scn_clearing) {
2341 scn->scn_checkpointing = B_TRUE;
2342 }
2343 }
2344
2345 if (!scn->scn_clearing && !scn->scn_checkpointing) {
2346 scn->scn_zio_root = zio_root(dp->dp_spa, NULL,
2347 NULL, ZIO_FLAG_CANFAIL);
2348 dsl_pool_config_enter(dp, FTAG);
2349 dsl_scan_visit(scn, tx);
2350 dsl_pool_config_exit(dp, FTAG);
2351 (void) zio_wait(scn->scn_zio_root);
2352 scn->scn_zio_root = NULL;
2353
2354 zfs_dbgmsg("visited %llu blocks in %llums",
2355 (longlong_t)scn->scn_visited_this_txg,
2356 (longlong_t)NSEC2MSEC(gethrtime() -
2357 scn->scn_sync_start_time));
2358
2359 if (!scn->scn_suspending) {
2360 scn->scn_done_txg = tx->tx_txg + 1;
2361 zfs_dbgmsg("txg %llu traversal complete, waiting "
2362 "till txg %llu", tx->tx_txg, scn->scn_done_txg);
2363 }
2364 }
2365 if (!scn->scn_suspending) {
2366 scn->scn_done_txg = tx->tx_txg + 1;
2367 zfs_dbgmsg("txg %llu traversal complete, waiting till txg %llu",
2368 tx->tx_txg, scn->scn_done_txg);
2369 }
2370 finish:
2371 if (scn->scn_is_sorted) {
2372 dsl_pool_config_enter(dp, FTAG);
2373 scan_io_queues_run(scn);
2374 dsl_pool_config_exit(dp, FTAG);
2375 }
2376
2377 if (DSL_SCAN_IS_SCRUB_RESILVER(scn)) {
2378 mutex_enter(&spa->spa_scrub_lock);
2379 while (spa->spa_scrub_inflight > 0) {
2380 cv_wait(&spa->spa_scrub_io_cv,
2381 &spa->spa_scrub_lock);
2382 }
2383 mutex_exit(&spa->spa_scrub_lock);
2384 }
2385
2386 dsl_scan_sync_state(scn, tx, SYNC_OPTIONAL);
2387 }
2388
2389 /*
2390 * This will start a new scan, or restart an existing one.
2391 */
2392 void
2393 dsl_resilver_restart(dsl_pool_t *dp, uint64_t txg)
2394 {
2395 /* Stop any ongoing TRIMs */
2396 spa_man_trim_stop(dp->dp_spa);
2397
2398 if (txg == 0) {
2399 dmu_tx_t *tx;
2400 tx = dmu_tx_create_dd(dp->dp_mos_dir);
2401 VERIFY(0 == dmu_tx_assign(tx, TXG_WAIT));
2402
2403 txg = dmu_tx_get_txg(tx);
2404 dp->dp_scan->scn_restart_txg = txg;
2405 dmu_tx_commit(tx);
2406 } else {
2407 dp->dp_scan->scn_restart_txg = txg;
2408 }
2409 zfs_dbgmsg("restarting resilver txg=%llu", txg);
2410 }
2411
2412 boolean_t
2413 dsl_scan_resilvering(dsl_pool_t *dp)
2414 {
2415 return (dsl_scan_is_running(dp->dp_scan) &&
2416 dp->dp_scan->scn_phys.scn_func == POOL_SCAN_RESILVER);
2417 }
2418
2419 /*
2420 * scrub consumers
2421 */
2422
2423 static void
2424 count_block(dsl_scan_t *scn, zfs_all_blkstats_t *zab, const blkptr_t *bp)
2425 {
2426 int i;
2427
2428 for (i = 0; i < BP_GET_NDVAS(bp); i++)
2429 atomic_add_64(&scn->scn_bytes_issued,
2430 DVA_GET_ASIZE(&bp->blk_dva[i]));
2431
2432 /*
2433 * If we resume after a reboot, zab will be NULL; don't record
2434 * incomplete stats in that case.
2435 */
2436 if (zab == NULL)
2437 return;
2438
2439 for (i = 0; i < 4; i++) {
2440 int l = (i < 2) ? BP_GET_LEVEL(bp) : DN_MAX_LEVELS;
2441 int t = (i & 1) ? BP_GET_TYPE(bp) : DMU_OT_TOTAL;
2442 if (t & DMU_OT_NEWTYPE)
2443 t = DMU_OT_OTHER;
2444 zfs_blkstat_t *zb = &zab->zab_type[l][t];
2445 int equal;
2446
2447 zb->zb_count++;
2448 zb->zb_asize += BP_GET_ASIZE(bp);
2449 zb->zb_lsize += BP_GET_LSIZE(bp);
2450 zb->zb_psize += BP_GET_PSIZE(bp);
2451 zb->zb_gangs += BP_COUNT_GANG(bp);
2465 DVA_GET_VDEV(&bp->blk_dva[2]));
2466 if (equal == 1)
2467 zb->zb_ditto_2_of_3_samevdev++;
2468 else if (equal == 3)
2469 zb->zb_ditto_3_of_3_samevdev++;
2470 break;
2471 }
2472 }
2473 }
2474
2475 static void
2476 dsl_scan_scrub_done(zio_t *zio)
2477 {
2478 spa_t *spa = zio->io_spa;
2479
2480 abd_free(zio->io_abd);
2481
2482 mutex_enter(&spa->spa_scrub_lock);
2483 spa->spa_scrub_inflight--;
2484 cv_broadcast(&spa->spa_scrub_io_cv);
2485 mutex_exit(&spa->spa_scrub_lock);
2486
2487 if (zio->io_error && (zio->io_error != ECKSUM ||
2488 !(zio->io_flags & ZIO_FLAG_SPECULATIVE))) {
2489 atomic_inc_64(&spa->spa_dsl_pool->dp_scan->scn_phys.scn_errors);
2490 DTRACE_PROBE1(scan_error, zio_t *, zio);
2491 }
2492 }
2493
2494 static int
2495 dsl_scan_scrub_cb(dsl_pool_t *dp,
2496 const blkptr_t *bp, const zbookmark_phys_t *zb)
2497 {
2498 dsl_scan_t *scn = dp->dp_scan;
2499 spa_t *spa = dp->dp_spa;
2500 uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
2501 boolean_t needs_io;
2502 int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
2503 boolean_t ignore_dva0;
2504
2505 if (phys_birth <= scn->scn_phys.scn_min_txg ||
2506 phys_birth >= scn->scn_phys.scn_max_txg)
2507 return (0);
2508
2509 if (BP_IS_EMBEDDED(bp)) {
2510 count_block(scn, dp->dp_blkstats, bp);
2511 return (0);
2512 }
2513
2514 ASSERT(DSL_SCAN_IS_SCRUB_RESILVER(scn));
2515 if (scn->scn_phys.scn_func == POOL_SCAN_SCRUB ||
2516 scn->scn_phys.scn_func == POOL_SCAN_MOS ||
2517 scn->scn_phys.scn_func == POOL_SCAN_META) {
2518 zio_flags |= ZIO_FLAG_SCRUB;
2519 needs_io = B_TRUE;
2520 } else {
2521 ASSERT3U(scn->scn_phys.scn_func, ==, POOL_SCAN_RESILVER);
2522 zio_flags |= ZIO_FLAG_RESILVER;
2523 needs_io = B_FALSE;
2524 }
2525
2526 /* If it's an intent log block, failure is expected. */
2527 if (zb->zb_level == ZB_ZIL_LEVEL)
2528 zio_flags |= ZIO_FLAG_SPECULATIVE;
2529
2530 if (scn->scn_phys.scn_func == POOL_SCAN_MOS)
2531 needs_io = (zb->zb_objset == 0);
2532
2533 if (scn->scn_phys.scn_func == POOL_SCAN_META)
2534 needs_io = zb->zb_objset == 0 || BP_GET_LEVEL(bp) != 0 ||
2535 DMU_OT_IS_METADATA(BP_GET_TYPE(bp));
2536
2537 DTRACE_PROBE3(scan_needs_io, boolean_t, needs_io,
2538 const blkptr_t *, bp, spa_t *, spa);
2539
2540 /*
2541 * WBC will invalidate DVA[0] after migrating the block to the main
2542 * pool. If the user subsequently disables WBC and removes the special
2543 * device, DVA[0] can now point to a hole vdev. We won't try to do
2544 * I/O to it, but we must also avoid doing DTL checks.
2545 */
2546 ignore_dva0 = (BP_IS_SPECIAL(bp) &&
2547 wbc_bp_is_migrated(spa_get_wbc_data(spa), bp));
2548
2549 for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
2550 vdev_t *vd;
2551
2552 /*
2553 * Keep track of how much data we've examined so that
2554 * zpool(1M) status can make useful progress reports.
2555 */
2556 scn->scn_phys.scn_examined += DVA_GET_ASIZE(&bp->blk_dva[d]);
2557 spa->spa_scan_pass_exam += DVA_GET_ASIZE(&bp->blk_dva[d]);
2558
2559 /* WBC-invalidated DVA post-migration, so skip it */
2560 if (d == 0 && ignore_dva0)
2561 continue;
2562 vd = vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[d]));
2563
2564 /* if it's a resilver, this may not be in the target range */
2565 if (!needs_io && scn->scn_phys.scn_func != POOL_SCAN_MOS &&
2566 scn->scn_phys.scn_func != POOL_SCAN_META) {
2567 if (DVA_GET_GANG(&bp->blk_dva[d])) {
2568 /*
2569 * Gang members may be spread across multiple
2570 * vdevs, so the best estimate we have is the
2571 * scrub range, which has already been checked.
2572 * XXX -- it would be better to change our
2573 * allocation policy to ensure that all
2574 * gang members reside on the same vdev.
2575 */
2576 needs_io = B_TRUE;
2577 DTRACE_PROBE2(gang_bp, const blkptr_t *, bp,
2578 spa_t *, spa);
2579 } else {
2580 needs_io = vdev_dtl_contains(vd, DTL_PARTIAL,
2581 phys_birth, 1);
2582 if (needs_io)
2583 DTRACE_PROBE2(dtl, const blkptr_t *,
2584 bp, spa_t *, spa);
2585 }
2586 }
2587 }
2588
2589 if (needs_io && !zfs_no_scrub_io) {
2590 dsl_scan_enqueue(dp, bp, zio_flags, zb);
2591 } else {
2592 count_block(scn, dp->dp_blkstats, bp);
2593 }
2594
2595 /* do not relocate this block */
2596 return (0);
2597 }
2598
2599 /*
2600 * Called by the ZFS_IOC_POOL_SCAN ioctl to start a scrub or resilver.
2601 * Can also be called to resume a paused scrub.
2602 */
2603 int
2604 dsl_scan(dsl_pool_t *dp, pool_scan_func_t func)
2605 {
2606 spa_t *spa = dp->dp_spa;
2607 dsl_scan_t *scn = dp->dp_scan;
2608
2609 /*
2610 * Purge all vdev caches and probe all devices. We do this here
2611 * rather than in sync context because this requires a writer lock
2612 * on the spa_config lock, which we can't do from sync context. The
2613 * spa_scrub_reopen flag indicates that vdev_open() should not
2614 * attempt to start another scrub.
2615 */
2616 spa_vdev_state_enter(spa, SCL_NONE);
2617 spa->spa_scrub_reopen = B_TRUE;
2618 vdev_reopen(spa->spa_root_vdev);
2619 spa->spa_scrub_reopen = B_FALSE;
2620 (void) spa_vdev_state_exit(spa, NULL, 0);
2621
2622 if (func == POOL_SCAN_SCRUB && dsl_scan_is_paused_scrub(scn)) {
2623 /* got scrub start cmd, resume paused scrub */
2624 int err = dsl_scrub_set_pause_resume(scn->scn_dp,
2625 POOL_SCRUB_NORMAL);
2626 if (err == 0)
2627 return (ECANCELED);
2628
2629 return (SET_ERROR(err));
2630 }
2631
2632 return (dsl_sync_task(spa_name(spa), dsl_scan_setup_check,
2633 dsl_scan_setup_sync, &func, 0, ZFS_SPACE_CHECK_NONE));
2634 }
2635
2636 static boolean_t
2637 dsl_scan_restarting(dsl_scan_t *scn, dmu_tx_t *tx)
2638 {
2639 return (scn->scn_restart_txg != 0 &&
2640 scn->scn_restart_txg <= tx->tx_txg);
2641 }
2642
2643 /*
2644 * Grand theory statement on scan queue sorting
2645 *
2646 * Scanning is implemented by recursively traversing all indirection levels
2647 * in an object and reading all blocks referenced from said objects. This
2648 * results in us approximately traversing the object from lowest logical
2649 * offset to the highest. Naturally, if we were simply read all blocks in
2650 * this order, we would require that the blocks be also physically arranged
2651 * in sort of a linear fashion on the vdevs. However, this is frequently
2652 * not the case on pools. So we instead stick the I/Os into a reordering
2653 * queue and issue them out of logical order and in a way that most benefits
2654 * physical disks (LBA-order).
2655 *
2656 * This sorting algorithm is subject to limitations. We can't do this with
2657 * blocks that are non-leaf, because the scanner itself depends on these
2658 * being available ASAP for further metadata traversal. So we exclude any
2659 * block that is bp_level > 0. Fortunately, this usually represents only
2660 * around 1% of our data volume, so no great loss.
2661 *
2662 * As a further limitation, we cannot sort blocks which have more than
2663 * one DVA present (copies > 1), because there's no sensible way to sort
2664 * these (how do you sort a queue based on multiple contradictory
2665 * criteria?). So we exclude those as well. Again, these are very rarely
2666 * used for leaf blocks, usually only on metadata.
2667 *
2668 * WBC consideration: we can't sort blocks which have not yet been fully
2669 * migrated to normal devices, because their data can reside purely on the
2670 * special device or on both normal and special. This would require larger
2671 * data structures to track both DVAs in our queues and we need the
2672 * smallest in-core structures we can possibly get to get good sorting
2673 * performance. Therefore, blocks which have not yet been fully migrated
2674 * out of the WBC are processed as non-sortable and issued immediately.
2675 *
2676 * Queue management:
2677 *
2678 * Ideally, we would want to scan all metadata and queue up all leaf block
2679 * I/O prior to starting to issue it, because that allows us to do an
2680 * optimal sorting job. This can however consume large amounts of memory.
2681 * Therefore we continuously monitor the size of the queues and constrain
2682 * them to 5% (zfs_scan_mem_lim_fact) of physmem. If the queues grow larger
2683 * than this limit, we clear out a few of the largest extents at the head
2684 * of the queues to make room for more scanning. Hopefully, these extents
2685 * will be fairly large and contiguous, allowing us to approach sequential
2686 * I/O throughput even without a fully sorted tree.
2687 *
2688 * Metadata scanning takes place in dsl_scan_visit(), which is called from
2689 * dsl_scan_sync() every spa_sync(). If we have either fully scanned all
2690 * metadata on the pool, or we need to make room in memory because our
2691 * queues are too large, dsl_scan_visit() is postponed and
2692 * scan_io_queues_run() is called from dsl_scan_sync() instead. That means,
2693 * metadata scanning and queued I/O issuing are mutually exclusive. This is
2694 * to provide maximum sequential I/O throughput for the queued I/O issue
2695 * process. Sequential I/O performance is significantly negatively impacted
2696 * if it is interleaved with random I/O.
2697 *
2698 * Backwards compatibility
2699 *
2700 * This new algorithm is backwards compatible with the legacy on-disk data
2701 * structures. If imported on a machine without the new sorting algorithm,
2702 * the scan simply resumes from the last checkpoint.
2703 */
2704
2705 /*
2706 * Given a set of I/O parameters as discovered by the metadata traversal
2707 * process, attempts to place the I/O into the reordering queue (if
2708 * possible), or immediately executes the I/O. The check for whether an
2709 * I/O is suitable for sorting is performed here.
2710 */
2711 static void
2712 dsl_scan_enqueue(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
2713 const zbookmark_phys_t *zb)
2714 {
2715 spa_t *spa = dp->dp_spa;
2716
2717 ASSERT(!BP_IS_EMBEDDED(bp));
2718 if (!dp->dp_scan->scn_is_sorted || (BP_IS_SPECIAL(bp) &&
2719 !wbc_bp_is_migrated(spa_get_wbc_data(spa), bp))) {
2720 scan_exec_io(dp, bp, zio_flags, zb, B_TRUE);
2721 return;
2722 }
2723
2724 for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
2725 dva_t dva;
2726 vdev_t *vdev;
2727
2728 /* On special BPs we only support handling the normal DVA */
2729 if (BP_IS_SPECIAL(bp) && i != WBC_NORMAL_DVA)
2730 continue;
2731
2732 dva = bp->blk_dva[i];
2733 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&dva));
2734 ASSERT(vdev != NULL);
2735
2736 mutex_enter(&vdev->vdev_scan_io_queue_lock);
2737 if (vdev->vdev_scan_io_queue == NULL)
2738 vdev->vdev_scan_io_queue = scan_io_queue_create(vdev);
2739 ASSERT(dp->dp_scan != NULL);
2740 scan_io_queue_insert(dp->dp_scan, vdev->vdev_scan_io_queue, bp,
2741 i, zio_flags, zb);
2742 mutex_exit(&vdev->vdev_scan_io_queue_lock);
2743 }
2744 }
2745
2746 /*
2747 * Given a scanning zio's information, executes the zio. The zio need
2748 * not necessarily be only sortable, this function simply executes the
2749 * zio, no matter what it is. The limit_inflight flag controls whether
2750 * we limit the number of concurrently executing scan zio's to
2751 * zfs_top_maxinflight times the number of top-level vdevs. This is
2752 * used during metadata discovery to pace the generation of I/O and
2753 * properly time the pausing of the scanning algorithm. The queue
2754 * processing part uses a different method of controlling timing and
2755 * so doesn't need this limit applied to its zio's.
2756 */
2757 static void
2758 scan_exec_io(dsl_pool_t *dp, const blkptr_t *bp, int zio_flags,
2759 const zbookmark_phys_t *zb, boolean_t limit_inflight)
2760 {
2761 spa_t *spa = dp->dp_spa;
2762 size_t size = BP_GET_PSIZE(bp);
2763 vdev_t *rvd = spa->spa_root_vdev;
2764 uint64_t maxinflight = rvd->vdev_children * zfs_top_maxinflight;
2765 dsl_scan_t *scn = dp->dp_scan;
2766 zio_priority_t prio;
2767
2768 mutex_enter(&spa->spa_scrub_lock);
2769 while (limit_inflight && spa->spa_scrub_inflight >= maxinflight)
2770 cv_wait(&spa->spa_scrub_io_cv, &spa->spa_scrub_lock);
2771 spa->spa_scrub_inflight++;
2772 mutex_exit(&spa->spa_scrub_lock);
2773
2774 for (int i = 0; i < BP_GET_NDVAS(bp); i++)
2775 atomic_add_64(&spa->spa_scan_pass_work,
2776 DVA_GET_ASIZE(&bp->blk_dva[i]));
2777
2778 count_block(dp->dp_scan, dp->dp_blkstats, bp);
2779 DTRACE_PROBE3(do_io, uint64_t, dp->dp_scan->scn_phys.scn_func,
2780 boolean_t, B_TRUE, spa_t *, spa);
2781 prio = (scn->scn_phys.scn_func == POOL_SCAN_RESILVER ?
2782 ZIO_PRIORITY_RESILVER : ZIO_PRIORITY_SCRUB);
2783 zio_nowait(zio_read(NULL, spa, bp, abd_alloc_for_io(size, B_FALSE),
2784 size, dsl_scan_scrub_done, NULL, prio, zio_flags, zb));
2785 }
2786
2787 /*
2788 * Given all the info we got from our metadata scanning process, we
2789 * construct a scan_io_t and insert it into the scan sorting queue. The
2790 * I/O must already be suitable for us to process. This is controlled
2791 * by dsl_scan_enqueue().
2792 */
2793 static void
2794 scan_io_queue_insert(dsl_scan_t *scn, dsl_scan_io_queue_t *queue,
2795 const blkptr_t *bp, int dva_i, int zio_flags, const zbookmark_phys_t *zb)
2796 {
2797 scan_io_t *sio = kmem_zalloc(sizeof (*sio), KM_SLEEP);
2798 avl_index_t idx;
2799 uint64_t offset, asize;
2800
2801 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
2802
2803 bp2sio(bp, sio, dva_i);
2804 sio->sio_flags = zio_flags;
2805 sio->sio_zb = *zb;
2806 offset = SCAN_IO_GET_OFFSET(sio);
2807 asize = sio->sio_asize;
2808
2809 if (avl_find(&queue->q_zios_by_addr, sio, &idx) != NULL) {
2810 /* block is already scheduled for reading */
2811 kmem_free(sio, sizeof (*sio));
2812 return;
2813 }
2814 avl_insert(&queue->q_zios_by_addr, sio, idx);
2815 atomic_add_64(&queue->q_zio_bytes, asize);
2816
2817 /*
2818 * Increment the bytes pending counter now so that we can't
2819 * get an integer underflow in case the worker processes the
2820 * zio before we get to incrementing this counter.
2821 */
2822 mutex_enter(&scn->scn_status_lock);
2823 scn->scn_bytes_pending += asize;
2824 mutex_exit(&scn->scn_status_lock);
2825
2826 range_tree_set_gap(queue->q_exts_by_addr, zfs_scan_max_ext_gap);
2827 range_tree_add_fill(queue->q_exts_by_addr, offset, asize, asize);
2828 }
2829
2830 /* q_exts_by_addr segment add callback. */
2831 /*ARGSUSED*/
2832 static void
2833 scan_io_queue_insert_cb(range_tree_t *rt, range_seg_t *rs, void *arg)
2834 {
2835 dsl_scan_io_queue_t *queue = arg;
2836 avl_index_t idx;
2837 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
2838 VERIFY3P(avl_find(&queue->q_exts_by_size, rs, &idx), ==, NULL);
2839 avl_insert(&queue->q_exts_by_size, rs, idx);
2840 }
2841
2842 /* q_exts_by_addr segment remove callback. */
2843 /*ARGSUSED*/
2844 static void
2845 scan_io_queue_remove_cb(range_tree_t *rt, range_seg_t *rs, void *arg)
2846 {
2847 dsl_scan_io_queue_t *queue = arg;
2848 avl_remove(&queue->q_exts_by_size, rs);
2849 }
2850
2851 /* q_exts_by_addr vacate callback. */
2852 /*ARGSUSED*/
2853 static void
2854 scan_io_queue_vacate_cb(range_tree_t *rt, void *arg)
2855 {
2856 dsl_scan_io_queue_t *queue = arg;
2857 void *cookie = NULL;
2858 while (avl_destroy_nodes(&queue->q_exts_by_size, &cookie) != NULL)
2859 ;
2860 }
2861
2862 /*
2863 * This is the primary extent sorting algorithm. We balance two parameters:
2864 * 1) how many bytes of I/O are in an extent
2865 * 2) how well the extent is filled with I/O (as a fraction of its total size)
2866 * Since we allow extents to have gaps between their constituent I/Os, it's
2867 * possible to have a fairly large extent that contains the same amount of
2868 * I/O bytes than a much smaller extent, which just packs the I/O more tightly.
2869 * The algorithm sorts based on a score calculated from the extent's size,
2870 * the relative fill volume (in %) and a "fill weight" parameter that controls
2871 * the split between whether we prefer larger extents or more well populated
2872 * extents:
2873 *
2874 * SCORE = FILL_IN_BYTES + (FILL_IN_PERCENT * FILL_IN_BYTES * FILL_WEIGHT)
2875 *
2876 * Example:
2877 * 1) assume extsz = 64 MiB
2878 * 2) assume fill = 32 MiB (extent is half full)
2879 * 3) assume fill_weight = 3
2880 * 4) SCORE = 32M + (((32M * 100) / 64M) * 3 * 32M) / 100
2881 * SCORE = 32M + (50 * 3 * 32M) / 100
2882 * SCORE = 32M + (4800M / 100)
2883 * SCORE = 32M + 48M
2884 * ^ ^
2885 * | +--- final total relative fill-based score
2886 * +--------- final total fill-based score
2887 * SCORE = 80M
2888 *
2889 * As can be seen, at fill_ratio=3, the algorithm is slightly biased towards
2890 * extents that are more completely filled (in a 3:2 ratio) vs just larger.
2891 */
2892 static int
2893 ext_size_compar(const void *x, const void *y)
2894 {
2895 const range_seg_t *rsa = x, *rsb = y;
2896 uint64_t sa = rsa->rs_end - rsa->rs_start,
2897 sb = rsb->rs_end - rsb->rs_start;
2898 uint64_t score_a, score_b;
2899
2900 score_a = rsa->rs_fill + (((rsa->rs_fill * 100) / sa) *
2901 fill_weight * rsa->rs_fill) / 100;
2902 score_b = rsb->rs_fill + (((rsb->rs_fill * 100) / sb) *
2903 fill_weight * rsb->rs_fill) / 100;
2904
2905 if (score_a > score_b)
2906 return (-1);
2907 if (score_a == score_b) {
2908 if (rsa->rs_start < rsb->rs_start)
2909 return (-1);
2910 if (rsa->rs_start == rsb->rs_start)
2911 return (0);
2912 return (1);
2913 }
2914 return (1);
2915 }
2916
2917 /*
2918 * Comparator for the q_zios_by_addr tree. Sorting is simply performed
2919 * based on LBA-order (from lowest to highest).
2920 */
2921 static int
2922 io_addr_compar(const void *x, const void *y)
2923 {
2924 const scan_io_t *a = x, *b = y;
2925 uint64_t off_a = SCAN_IO_GET_OFFSET(a);
2926 uint64_t off_b = SCAN_IO_GET_OFFSET(b);
2927 if (off_a < off_b)
2928 return (-1);
2929 if (off_a == off_b)
2930 return (0);
2931 return (1);
2932 }
2933
2934 static dsl_scan_io_queue_t *
2935 scan_io_queue_create(vdev_t *vd)
2936 {
2937 dsl_scan_t *scn = vd->vdev_spa->spa_dsl_pool->dp_scan;
2938 dsl_scan_io_queue_t *q = kmem_zalloc(sizeof (*q), KM_SLEEP);
2939
2940 q->q_scn = scn;
2941 q->q_vd = vd;
2942 cv_init(&q->q_cv, NULL, CV_DEFAULT, NULL);
2943 q->q_exts_by_addr = range_tree_create(&scan_io_queue_ops, q,
2944 &q->q_vd->vdev_scan_io_queue_lock);
2945 avl_create(&q->q_exts_by_size, ext_size_compar,
2946 sizeof (range_seg_t), offsetof(range_seg_t, rs_pp_node));
2947 avl_create(&q->q_zios_by_addr, io_addr_compar,
2948 sizeof (scan_io_t), offsetof(scan_io_t, sio_nodes.sio_addr_node));
2949
2950 return (q);
2951 }
2952
2953 /*
2954 * Destroyes a scan queue and all segments and scan_io_t's contained in it.
2955 * No further execution of I/O occurs, anything pending in the queue is
2956 * simply dropped. Prior to calling this, the queue should have been
2957 * removed from its parent top-level vdev, hence holding the queue's
2958 * lock is not permitted.
2959 */
2960 void
2961 dsl_scan_io_queue_destroy(dsl_scan_io_queue_t *queue)
2962 {
2963 dsl_scan_t *scn = queue->q_scn;
2964 scan_io_t *sio;
2965 uint64_t bytes_dequeued = 0;
2966 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock;
2967
2968 ASSERT(!MUTEX_HELD(q_lock));
2969
2970 #ifdef DEBUG /* This is for the ASSERT(range_tree_contains... below */
2971 mutex_enter(q_lock);
2972 #endif
2973 while ((sio = avl_first(&queue->q_zios_by_addr)) != NULL) {
2974 ASSERT(range_tree_contains(queue->q_exts_by_addr,
2975 SCAN_IO_GET_OFFSET(sio), sio->sio_asize));
2976 bytes_dequeued += sio->sio_asize;
2977 avl_remove(&queue->q_zios_by_addr, sio);
2978 kmem_free(sio, sizeof (*sio));
2979 }
2980 #ifdef DEBUG
2981 mutex_exit(q_lock);
2982 #endif
2983
2984 mutex_enter(&scn->scn_status_lock);
2985 ASSERT3U(scn->scn_bytes_pending, >=, bytes_dequeued);
2986 scn->scn_bytes_pending -= bytes_dequeued;
2987 mutex_exit(&scn->scn_status_lock);
2988
2989 /* lock here to avoid tripping assertion in range_tree_vacate */
2990 mutex_enter(q_lock);
2991 range_tree_vacate(queue->q_exts_by_addr, NULL, queue);
2992 mutex_exit(q_lock);
2993
2994 range_tree_destroy(queue->q_exts_by_addr);
2995 avl_destroy(&queue->q_exts_by_size);
2996 avl_destroy(&queue->q_zios_by_addr);
2997 cv_destroy(&queue->q_cv);
2998
2999 kmem_free(queue, sizeof (*queue));
3000 }
3001
3002 /*
3003 * Properly transfers a dsl_scan_queue_t from `svd' to `tvd'. This is
3004 * called on behalf of vdev_top_transfer when creating or destroying
3005 * a mirror vdev due to zpool attach/detach.
3006 */
3007 void
3008 dsl_scan_io_queue_vdev_xfer(vdev_t *svd, vdev_t *tvd)
3009 {
3010 mutex_enter(&svd->vdev_scan_io_queue_lock);
3011 mutex_enter(&tvd->vdev_scan_io_queue_lock);
3012
3013 VERIFY3P(tvd->vdev_scan_io_queue, ==, NULL);
3014 tvd->vdev_scan_io_queue = svd->vdev_scan_io_queue;
3015 svd->vdev_scan_io_queue = NULL;
3016 if (tvd->vdev_scan_io_queue != NULL) {
3017 tvd->vdev_scan_io_queue->q_vd = tvd;
3018 range_tree_set_lock(tvd->vdev_scan_io_queue->q_exts_by_addr,
3019 &tvd->vdev_scan_io_queue_lock);
3020 }
3021
3022 mutex_exit(&tvd->vdev_scan_io_queue_lock);
3023 mutex_exit(&svd->vdev_scan_io_queue_lock);
3024 }
3025
3026 static void
3027 scan_io_queues_destroy(dsl_scan_t *scn)
3028 {
3029 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
3030
3031 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
3032 vdev_t *tvd = rvd->vdev_child[i];
3033 dsl_scan_io_queue_t *queue;
3034
3035 mutex_enter(&tvd->vdev_scan_io_queue_lock);
3036 queue = tvd->vdev_scan_io_queue;
3037 tvd->vdev_scan_io_queue = NULL;
3038 mutex_exit(&tvd->vdev_scan_io_queue_lock);
3039
3040 if (queue != NULL)
3041 dsl_scan_io_queue_destroy(queue);
3042 }
3043 }
3044
3045 /*
3046 * Computes the memory limit state that we're currently in. A sorted scan
3047 * needs quite a bit of memory to hold the sorting queues, so we need to
3048 * reasonably constrain their size so they don't impact overall system
3049 * performance. We compute two limits:
3050 * 1) Hard memory limit: if the amount of memory used by the sorting
3051 * queues on a pool gets above this value, we stop the metadata
3052 * scanning portion and start issuing the queued up and sorted
3053 * I/Os to reduce memory usage.
3054 * This limit is calculated as a fraction of physmem (by default 5%).
3055 * We constrain the lower bound of the hard limit to an absolute
3056 * minimum of zfs_scan_mem_lim_min (default: 16 MiB). We also constrain
3057 * the upper bound to 5% of the total pool size - no chance we'll
3058 * ever need that much memory, but just to keep the value in check.
3059 * 2) Soft memory limit: once we hit the hard memory limit, we start
3060 * issuing I/O to lower queue memory usage, but we don't want to
3061 * completely empty them out, as having more in the queues allows
3062 * us to make better sorting decisions. So we stop the issuing of
3063 * I/Os once the amount of memory used drops below the soft limit
3064 * (at which point we stop issuing I/O and start scanning metadata
3065 * again).
3066 * The limit is calculated by subtracting a fraction of the hard
3067 * limit from the hard limit. By default this fraction is 10%, so
3068 * the soft limit is 90% of the hard limit. We cap the size of the
3069 * difference between the hard and soft limits at an absolute
3070 * maximum of zfs_scan_mem_lim_soft_max (default: 128 MiB) - this is
3071 * sufficient to not cause too frequent switching between the
3072 * metadata scan and I/O issue (even at 2k recordsize, 128 MiB's
3073 * worth of queues is about 1.2 GiB of on-pool data, so scanning
3074 * that should take at least a decent fraction of a second).
3075 */
3076 static mem_lim_t
3077 scan_io_queue_mem_lim(dsl_scan_t *scn)
3078 {
3079 vdev_t *rvd = scn->scn_dp->dp_spa->spa_root_vdev;
3080 uint64_t mlim_hard, mlim_soft, mused;
3081 uint64_t alloc = metaslab_class_get_alloc(spa_normal_class(
3082 scn->scn_dp->dp_spa));
3083
3084 mlim_hard = MAX((physmem / zfs_scan_mem_lim_fact) * PAGESIZE,
3085 zfs_scan_mem_lim_min);
3086 mlim_hard = MIN(mlim_hard, alloc / 20);
3087 mlim_soft = mlim_hard - MIN(mlim_hard / zfs_scan_mem_lim_soft_fact,
3088 zfs_scan_mem_lim_soft_max);
3089 mused = 0;
3090 for (uint64_t i = 0; i < rvd->vdev_children; i++) {
3091 vdev_t *tvd = rvd->vdev_child[i];
3092 dsl_scan_io_queue_t *queue;
3093
3094 mutex_enter(&tvd->vdev_scan_io_queue_lock);
3095 queue = tvd->vdev_scan_io_queue;
3096 if (queue != NULL) {
3097 /* #extents in exts_by_size = # in exts_by_addr */
3098 mused += avl_numnodes(&queue->q_exts_by_size) *
3099 sizeof (range_seg_t) +
3100 (avl_numnodes(&queue->q_zios_by_addr) +
3101 queue->q_num_issuing_zios) * sizeof (scan_io_t);
3102 }
3103 mutex_exit(&tvd->vdev_scan_io_queue_lock);
3104 }
3105 DTRACE_PROBE4(queue_mem_lim, dsl_scan_t *, scn, uint64_t, mlim_hard,
3106 uint64_t, mlim_soft, uint64_t, mused);
3107
3108 if (mused >= mlim_hard)
3109 return (MEM_LIM_HARD);
3110 else if (mused >= mlim_soft)
3111 return (MEM_LIM_SOFT);
3112 else
3113 return (MEM_LIM_NONE);
3114 }
3115
3116 /*
3117 * Given a list of scan_io_t's in io_list, this issues the io's out to
3118 * disk. Passing shutdown=B_TRUE instead discards the zio's without
3119 * issuing them. This consumes the io_list and frees the scan_io_t's.
3120 * This is called when emptying queues, either when we're up against
3121 * the memory limit or we have finished scanning.
3122 */
3123 static void
3124 scan_io_queue_issue(list_t *io_list, dsl_scan_io_queue_t *queue)
3125 {
3126 dsl_scan_t *scn = queue->q_scn;
3127 scan_io_t *sio;
3128 int64_t bytes_issued = 0;
3129
3130 while ((sio = list_head(io_list)) != NULL) {
3131 blkptr_t bp;
3132
3133 sio2bp(sio, &bp, queue->q_vd->vdev_id);
3134 bytes_issued += sio->sio_asize;
3135 scan_exec_io(scn->scn_dp, &bp, sio->sio_flags, &sio->sio_zb,
3136 B_FALSE);
3137 (void) list_remove_head(io_list);
3138 ASSERT(queue->q_num_issuing_zios > 0);
3139 atomic_dec_64(&queue->q_num_issuing_zios);
3140 kmem_free(sio, sizeof (*sio));
3141 }
3142
3143 mutex_enter(&scn->scn_status_lock);
3144 ASSERT3U(scn->scn_bytes_pending, >=, bytes_issued);
3145 scn->scn_bytes_pending -= bytes_issued;
3146 mutex_exit(&scn->scn_status_lock);
3147
3148 ASSERT3U(queue->q_zio_bytes, >=, bytes_issued);
3149 atomic_add_64(&queue->q_zio_bytes, -bytes_issued);
3150
3151 list_destroy(io_list);
3152 }
3153
3154 /*
3155 * Given a range_seg_t (extent) and a list, this function passes over a
3156 * scan queue and gathers up the appropriate ios which fit into that
3157 * scan seg (starting from lowest LBA). During this, we observe that we
3158 * don't go over the `limit' in the total amount of scan_io_t bytes that
3159 * were gathered. At the end, we remove the appropriate amount of space
3160 * from the q_exts_by_addr. If we have consumed the entire scan seg, we
3161 * remove it completely from q_exts_by_addr. If we've only consumed a
3162 * portion of it, we shorten the scan seg appropriately. A future call
3163 * will consume more of the scan seg's constituent io's until
3164 * consuming the extent completely. If we've reduced the size of the
3165 * scan seg, we of course reinsert it in the appropriate spot in the
3166 * q_exts_by_size tree.
3167 */
3168 static uint64_t
3169 scan_io_queue_gather(const range_seg_t *rs, list_t *list,
3170 dsl_scan_io_queue_t *queue, uint64_t limit)
3171 {
3172 scan_io_t srch_sio, *sio, *next_sio;
3173 avl_index_t idx;
3174 int64_t num_zios = 0, bytes = 0;
3175 boolean_t size_limited = B_FALSE;
3176
3177 ASSERT(rs != NULL);
3178 ASSERT3U(limit, !=, 0);
3179 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
3180
3181 list_create(list, sizeof (scan_io_t),
3182 offsetof(scan_io_t, sio_nodes.sio_list_node));
3183 SCAN_IO_SET_OFFSET(&srch_sio, rs->rs_start);
3184
3185 /*
3186 * The exact start of the extent might not contain any matching zios,
3187 * so if that's the case, examine the next one in the tree.
3188 */
3189 sio = avl_find(&queue->q_zios_by_addr, &srch_sio, &idx);
3190 if (sio == NULL)
3191 sio = avl_nearest(&queue->q_zios_by_addr, idx, AVL_AFTER);
3192
3193 while (sio != NULL && SCAN_IO_GET_OFFSET(sio) < rs->rs_end) {
3194 if (bytes >= limit) {
3195 size_limited = B_TRUE;
3196 break;
3197 }
3198 ASSERT3U(SCAN_IO_GET_OFFSET(sio), >=, rs->rs_start);
3199 ASSERT3U(SCAN_IO_GET_OFFSET(sio) + sio->sio_asize, <=,
3200 rs->rs_end);
3201
3202 next_sio = AVL_NEXT(&queue->q_zios_by_addr, sio);
3203 avl_remove(&queue->q_zios_by_addr, sio);
3204 list_insert_tail(list, sio);
3205 num_zios++;
3206 bytes += sio->sio_asize;
3207 sio = next_sio;
3208 }
3209
3210 if (size_limited) {
3211 uint64_t end;
3212 sio = list_tail(list);
3213 end = SCAN_IO_GET_OFFSET(sio) + sio->sio_asize;
3214 range_tree_remove_fill(queue->q_exts_by_addr, rs->rs_start,
3215 end - rs->rs_start, bytes, 0);
3216 } else {
3217 /*
3218 * Whole extent consumed, remove it all, including any head
3219 * or tail overhang.
3220 */
3221 range_tree_remove_fill(queue->q_exts_by_addr, rs->rs_start,
3222 rs->rs_end - rs->rs_start, bytes, 0);
3223 }
3224 atomic_add_64(&queue->q_num_issuing_zios, num_zios);
3225
3226 return (bytes);
3227 }
3228
3229 /*
3230 * This is called from the queue emptying thread and selects the next
3231 * extent from which we are to issue io's. The behavior of this function
3232 * depends on the state of the scan, the current memory consumption and
3233 * whether or not we are performing a scan shutdown.
3234 * 1) We select extents in an elevator algorithm (LBA-order) if:
3235 * a) the scan has finished traversing metadata (DSS_FINISHING)
3236 * b) the scan needs to perform a checkpoint
3237 * 2) We select the largest available extent if we are up against the
3238 * memory limit.
3239 * 3) Otherwise we don't select any extents.
3240 */
3241 static const range_seg_t *
3242 scan_io_queue_fetch_ext(dsl_scan_io_queue_t *queue)
3243 {
3244 dsl_scan_t *scn = queue->q_scn;
3245
3246 ASSERT(MUTEX_HELD(&queue->q_vd->vdev_scan_io_queue_lock));
3247 ASSERT0(queue->q_issuing_rs.rs_start);
3248 ASSERT0(queue->q_issuing_rs.rs_end);
3249 ASSERT(scn->scn_is_sorted);
3250
3251 if (scn->scn_phys.scn_state == DSS_FINISHING ||
3252 scn->scn_checkpointing) {
3253 /*
3254 * When the scan has finished traversing all metadata and is
3255 * in the DSS_FINISHING state or a checkpoint has been
3256 * requested, no new extents will be added to the sorting
3257 * queue, so the way we are sorted now is as good as it'll
3258 * get. So instead, switch to issuing extents in linear order.
3259 */
3260 return (range_tree_first(queue->q_exts_by_addr));
3261 } else if (scn->scn_clearing) {
3262 return (avl_first(&queue->q_exts_by_size));
3263 } else {
3264 return (NULL);
3265 }
3266 }
3267
3268 /*
3269 * Empties a scan queue until we have issued at least info->qri_limit
3270 * bytes, or the queue is empty. This is called via the scn_taskq so as
3271 * to parallelize processing of all top-level vdevs as much as possible.
3272 */
3273 static void
3274 scan_io_queues_run_one(io_queue_run_info_t *info)
3275 {
3276 dsl_scan_io_queue_t *queue = info->qri_queue;
3277 uint64_t limit = info->qri_limit;
3278 dsl_scan_t *scn = queue->q_scn;
3279 kmutex_t *q_lock = &queue->q_vd->vdev_scan_io_queue_lock;
3280 list_t zio_list;
3281 const range_seg_t *rs;
3282 uint64_t issued = 0;
3283
3284 ASSERT(scn->scn_is_sorted);
3285
3286 /* loop until we have issued as much I/O as was requested */
3287 while (issued < limit) {
3288 scan_io_t *first_io, *last_io;
3289
3290 mutex_enter(q_lock);
3291 /* First we select the extent we'll be issuing from next. */
3292 rs = scan_io_queue_fetch_ext(queue);
3293 DTRACE_PROBE2(queue_fetch_ext, range_seg_t *, rs,
3294 dsl_scan_io_queue_t *, queue);
3295 if (rs == NULL) {
3296 mutex_exit(q_lock);
3297 break;
3298 }
3299
3300 /*
3301 * We have selected which extent needs to be processed next,
3302 * gather up the corresponding zio's, taking care not to step
3303 * over the limit.
3304 */
3305 issued += scan_io_queue_gather(rs, &zio_list, queue,
3306 limit - issued);
3307 first_io = list_head(&zio_list);
3308 last_io = list_tail(&zio_list);
3309 if (first_io != NULL) {
3310 /*
3311 * We have zio's to issue. Construct a fake range
3312 * seg that covers the whole list of zio's to issue
3313 * (the list is guaranteed to be LBA-ordered) and
3314 * save that in the queue's "in flight" segment.
3315 * This is used to prevent freeing I/O from hitting
3316 * that range while we're working on it.
3317 */
3318 ASSERT(last_io != NULL);
3319 queue->q_issuing_rs.rs_start =
3320 SCAN_IO_GET_OFFSET(first_io);
3321 queue->q_issuing_rs.rs_end =
3322 SCAN_IO_GET_OFFSET(last_io) + last_io->sio_asize;
3323 }
3324 mutex_exit(q_lock);
3325
3326 /*
3327 * Issuing zio's can take a long time (especially because
3328 * we are contrained by zfs_top_maxinflight), so drop the
3329 * queue lock.
3330 */
3331 scan_io_queue_issue(&zio_list, queue);
3332
3333 mutex_enter(q_lock);
3334 /* invalidate the in-flight I/O range */
3335 bzero(&queue->q_issuing_rs, sizeof (queue->q_issuing_rs));
3336 cv_broadcast(&queue->q_cv);
3337 mutex_exit(q_lock);
3338 }
3339 }
3340
3341 /*
3342 * Performs an emptying run on all scan queues in the pool. This just
3343 * punches out one thread per top-level vdev, each of which processes
3344 * only that vdev's scan queue. We can parallelize the I/O here because
3345 * we know that each queue's io's only affect its own top-level vdev.
3346 * The amount of I/O dequeued per run of this function is calibrated
3347 * dynamically so that its total run time doesn't exceed
3348 * zfs_scan_dequeue_run_target_ms + zfs_dequeue_run_bonus_ms. The
3349 * timing algorithm aims to hit the target value, but still
3350 * oversubscribes the amount of data that it is allowed to fetch by
3351 * the bonus value. This is to allow for non-equal completion times
3352 * across top-level vdevs.
3353 *
3354 * This function waits for the queue runs to complete, and must be
3355 * called from dsl_scan_sync (or in general, syncing context).
3356 */
3357 static void
3358 scan_io_queues_run(dsl_scan_t *scn)
3359 {
3360 spa_t *spa = scn->scn_dp->dp_spa;
3361 uint64_t dirty_limit, total_limit, total_bytes;
3362 io_queue_run_info_t *info;
3363 uint64_t dequeue_min = zfs_scan_dequeue_min *
3364 spa->spa_root_vdev->vdev_children;
3365
3366 ASSERT(scn->scn_is_sorted);
3367 ASSERT(spa_config_held(spa, SCL_CONFIG, RW_READER));
3368
3369 if (scn->scn_taskq == NULL) {
3370 char *tq_name = kmem_zalloc(ZFS_MAX_DATASET_NAME_LEN + 16,
3371 KM_SLEEP);
3372 const int nthreads = spa->spa_root_vdev->vdev_children;
3373
3374 /*
3375 * We need to make this taskq *always* execute as many
3376 * threads in parallel as we have top-level vdevs and no
3377 * less, otherwise strange serialization of the calls to
3378 * scan_io_queues_run_one can occur during spa_sync runs
3379 * and that significantly impacts performance.
3380 */
3381 (void) snprintf(tq_name, ZFS_MAX_DATASET_NAME_LEN + 16,
3382 "dsl_scan_tq_%s", spa->spa_name);
3383 scn->scn_taskq = taskq_create(tq_name, nthreads, minclsyspri,
3384 nthreads, nthreads, TASKQ_PREPOPULATE);
3385 kmem_free(tq_name, ZFS_MAX_DATASET_NAME_LEN + 16);
3386 }
3387
3388 /*
3389 * This is the automatic run time calibration algorithm. We gauge
3390 * how long spa_sync took since last time we were invoked. If it
3391 * took longer than our target + bonus values, we reduce the
3392 * amount of data that the queues are allowed to process in this
3393 * iteration. Conversely, if it took less than target + bonus,
3394 * we increase the amount of data the queues are allowed to process.
3395 * This is designed as a partial load-following algorithm, so if
3396 * other ZFS users start issuing I/O, we back off, until we hit our
3397 * minimum issue amount (per-TL-vdev) of zfs_scan_dequeue_min bytes.
3398 */
3399 if (scn->scn_last_queue_run_time != 0) {
3400 uint64_t now = ddi_get_lbolt64();
3401 uint64_t delta_ms = TICK_TO_MSEC(now -
3402 scn->scn_last_queue_run_time);
3403 uint64_t bonus = zfs_dequeue_run_bonus_ms;
3404
3405 bonus = MIN(bonus, DEQUEUE_BONUS_MS_MAX);
3406 if (delta_ms <= bonus)
3407 delta_ms = bonus + 1;
3408
3409 scn->scn_last_dequeue_limit = MAX(dequeue_min,
3410 (scn->scn_last_dequeue_limit *
3411 zfs_scan_dequeue_run_target_ms) / (delta_ms - bonus));
3412 scn->scn_last_queue_run_time = now;
3413 } else {
3414 scn->scn_last_queue_run_time = ddi_get_lbolt64();
3415 scn->scn_last_dequeue_limit = dequeue_min;
3416 }
3417
3418 /*
3419 * We also constrain the amount of data we are allowed to issue
3420 * by the zfs_dirty_data_max value - this serves as basically a
3421 * sanity check just to prevent us from issuing huge amounts of
3422 * data to be dequeued per run.
3423 */
3424 dirty_limit = (zfs_vdev_async_write_active_min_dirty_percent *
3425 zfs_dirty_data_max) / 100;
3426 if (dirty_limit >= scn->scn_dp->dp_dirty_total)
3427 dirty_limit -= scn->scn_dp->dp_dirty_total;
3428 else
3429 dirty_limit = 0;
3430
3431 total_limit = MAX(MIN(scn->scn_last_dequeue_limit, dirty_limit),
3432 dequeue_min);
3433
3434 /*
3435 * We use this to determine how much data each queue is allowed to
3436 * issue this run. We take the amount of dirty data available in
3437 * the current txg and proportionally split it between each queue,
3438 * depending on how full a given queue is. No need to lock here,
3439 * new data can't enter the queue, since that's only done in our
3440 * sync thread.
3441 */
3442 total_bytes = scn->scn_bytes_pending;
3443 if (total_bytes == 0)
3444 return;
3445
3446 info = kmem_zalloc(sizeof (*info) * spa->spa_root_vdev->vdev_children,
3447 KM_SLEEP);
3448 for (uint64_t i = 0; i < spa->spa_root_vdev->vdev_children; i++) {
3449 vdev_t *vd = spa->spa_root_vdev->vdev_child[i];
3450 dsl_scan_io_queue_t *queue;
3451 uint64_t limit;
3452
3453 /*
3454 * No need to lock to check if the queue exists, since this
3455 * is called from sync context only and queues are only
3456 * created in sync context also.
3457 */
3458 queue = vd->vdev_scan_io_queue;
3459 if (queue == NULL)
3460 continue;
3461
3462 /*
3463 * Compute the per-queue limit as a fraction of the queue's
3464 * size, relative to the total amount of zio bytes in all
3465 * all queues. 1000 here is the fixed-point precision. If
3466 * there are ever more than 1000 top-level vdevs, this
3467 * code might misbehave.
3468 */
3469 limit = MAX((((queue->q_zio_bytes * 1000) / total_bytes) *
3470 total_limit) / 1000, zfs_scan_dequeue_min);
3471
3472 info[i].qri_queue = queue;
3473 info[i].qri_limit = limit;
3474
3475 VERIFY(taskq_dispatch(scn->scn_taskq,
3476 (void (*)(void *))scan_io_queues_run_one, &info[i],
3477 TQ_SLEEP) != NULL);
3478 }
3479
3480 /*
3481 * We need to wait for all queues to finish their run, just to keep
3482 * things nice and consistent. This doesn't necessarily mean all
3483 * I/O generated by the queues emptying has finished (there may be
3484 * up to zfs_top_maxinflight zio's still processing on behalf of
3485 * each queue).
3486 */
3487 taskq_wait(scn->scn_taskq);
3488
3489 kmem_free(info, sizeof (*info) * spa->spa_root_vdev->vdev_children);
3490 }
3491
3492 /*
3493 * Callback invoked when a zio_free() zio is executing. This needs to be
3494 * intercepted to prevent the zio from deallocating a particular portion
3495 * of disk space and it then getting reallocated and written to, while we
3496 * still have it queued up for processing, or even while we're trying to
3497 * scrub or resilver it.
3498 */
3499 void
3500 dsl_scan_freed(spa_t *spa, const blkptr_t *bp)
3501 {
3502 dsl_pool_t *dp = spa->spa_dsl_pool;
3503 dsl_scan_t *scn = dp->dp_scan;
3504
3505 ASSERT(!BP_IS_EMBEDDED(bp));
3506 ASSERT(scn != NULL);
3507 if (!dsl_scan_is_running(scn))
3508 return;
3509
3510 for (int i = 0; i < BP_GET_NDVAS(bp); i++) {
3511 if (BP_IS_SPECIAL(bp) && i != WBC_NORMAL_DVA)
3512 continue;
3513 dsl_scan_freed_dva(spa, bp, i);
3514 }
3515 }
3516
3517 static void
3518 dsl_scan_freed_dva(spa_t *spa, const blkptr_t *bp, int dva_i)
3519 {
3520 dsl_pool_t *dp = spa->spa_dsl_pool;
3521 dsl_scan_t *scn = dp->dp_scan;
3522 vdev_t *vdev;
3523 kmutex_t *q_lock;
3524 dsl_scan_io_queue_t *queue;
3525 scan_io_t srch, *sio;
3526 avl_index_t idx;
3527 uint64_t offset;
3528 int64_t asize;
3529
3530 ASSERT(!BP_IS_EMBEDDED(bp));
3531 ASSERT(scn != NULL);
3532 ASSERT(!BP_IS_SPECIAL(bp) || dva_i == WBC_NORMAL_DVA);
3533
3534 vdev = vdev_lookup_top(spa, DVA_GET_VDEV(&bp->blk_dva[dva_i]));
3535 ASSERT(vdev != NULL);
3536 q_lock = &vdev->vdev_scan_io_queue_lock;
3537 queue = vdev->vdev_scan_io_queue;
3538
3539 mutex_enter(q_lock);
3540 if (queue == NULL) {
3541 mutex_exit(q_lock);
3542 return;
3543 }
3544
3545 bp2sio(bp, &srch, dva_i);
3546 offset = SCAN_IO_GET_OFFSET(&srch);
3547 asize = srch.sio_asize;
3548
3549 /*
3550 * We can find the zio in two states:
3551 * 1) Cold, just sitting in the queue of zio's to be issued at
3552 * some point in the future. In this case, all we do is
3553 * remove the zio from the q_zios_by_addr tree, decrement
3554 * its data volume from the containing range_seg_t and
3555 * resort the q_exts_by_size tree to reflect that the
3556 * range_seg_t has lost some of its 'fill'. We don't shorten
3557 * the range_seg_t - this is usually rare enough not to be
3558 * worth the extra hassle of trying keep track of precise
3559 * extent boundaries.
3560 * 2) Hot, where the zio is currently in-flight in
3561 * dsl_scan_issue_ios. In this case, we can't simply
3562 * reach in and stop the in-flight zio's, so we instead
3563 * block the caller. Eventually, dsl_scan_issue_ios will
3564 * be done with issuing the zio's it gathered and will
3565 * signal us.
3566 */
3567 sio = avl_find(&queue->q_zios_by_addr, &srch, &idx);
3568 if (sio != NULL) {
3569 range_seg_t *rs;
3570
3571 /* Got it while it was cold in the queue */
3572 ASSERT3U(srch.sio_asize, ==, sio->sio_asize);
3573 DTRACE_PROBE2(dequeue_now, const blkptr_t *, bp,
3574 dsl_scan_queue_t *, queue);
3575 count_block(scn, dp->dp_blkstats, bp);
3576 ASSERT(range_tree_contains(queue->q_exts_by_addr, offset,
3577 asize));
3578 avl_remove(&queue->q_zios_by_addr, sio);
3579
3580 /*
3581 * Since we're taking this scan_io_t out of its parent
3582 * range_seg_t, we need to alter the range_seg_t's rs_fill
3583 * value, so this changes its ordering position. We need
3584 * to reinsert in its appropriate place in q_exts_by_size.
3585 */
3586 rs = range_tree_find(queue->q_exts_by_addr,
3587 SCAN_IO_GET_OFFSET(sio), sio->sio_asize);
3588 ASSERT(rs != NULL);
3589 ASSERT3U(rs->rs_fill, >=, sio->sio_asize);
3590 avl_remove(&queue->q_exts_by_size, rs);
3591 ASSERT3U(rs->rs_fill, >=, sio->sio_asize);
3592 rs->rs_fill -= sio->sio_asize;
3593 VERIFY3P(avl_find(&queue->q_exts_by_size, rs, &idx), ==, NULL);
3594 avl_insert(&queue->q_exts_by_size, rs, idx);
3595
3596 /*
3597 * We only update the queue byte counter in the cold path,
3598 * otherwise it will already have been accounted for as
3599 * part of the zio's execution.
3600 */
3601 ASSERT3U(queue->q_zio_bytes, >=, asize);
3602 atomic_add_64(&queue->q_zio_bytes, -asize);
3603
3604 mutex_enter(&scn->scn_status_lock);
3605 ASSERT3U(scn->scn_bytes_pending, >=, asize);
3606 scn->scn_bytes_pending -= asize;
3607 mutex_exit(&scn->scn_status_lock);
3608
3609 kmem_free(sio, sizeof (*sio));
3610 } else {
3611 /*
3612 * If it's part of an extent that's currently being issued,
3613 * wait until the extent has been consumed. In this case it's
3614 * not us who is dequeueing this zio, so no need to
3615 * decrement its size from scn_bytes_pending or the queue.
3616 */
3617 while (queue->q_issuing_rs.rs_start <= offset &&
3618 queue->q_issuing_rs.rs_end >= offset + asize) {
3619 DTRACE_PROBE2(dequeue_wait, const blkptr_t *, bp,
3620 dsl_scan_queue_t *, queue);
3621 cv_wait(&queue->q_cv, &vdev->vdev_scan_io_queue_lock);
3622 }
3623 }
3624 mutex_exit(q_lock);
3625 }
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