1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2012, 2016 by Delphix. All rights reserved.
24 */
25
26 #include <sys/zfs_context.h>
27 #include <sys/dmu_objset.h>
28 #include <sys/dmu_traverse.h>
29 #include <sys/dsl_dataset.h>
30 #include <sys/dsl_dir.h>
31 #include <sys/dsl_pool.h>
32 #include <sys/dnode.h>
33 #include <sys/spa.h>
34 #include <sys/zio.h>
35 #include <sys/dmu_impl.h>
36 #include <sys/sa.h>
37 #include <sys/sa_impl.h>
38 #include <sys/callb.h>
39 #include <sys/zfeature.h>
40
41 int32_t zfs_pd_bytes_max = 50 * 1024 * 1024; /* 50MB */
42
43 typedef struct prefetch_data {
44 kmutex_t pd_mtx;
45 kcondvar_t pd_cv;
46 int32_t pd_bytes_fetched;
47 int pd_flags;
48 boolean_t pd_cancel;
49 boolean_t pd_exited;
50 zbookmark_phys_t pd_resume;
51 } prefetch_data_t;
52
53 typedef struct traverse_data {
54 spa_t *td_spa;
55 uint64_t td_objset;
56 blkptr_t *td_rootbp;
57 uint64_t td_min_txg;
58 zbookmark_phys_t *td_resume;
59 int td_flags;
60 prefetch_data_t *td_pfd;
61 boolean_t td_paused;
62 uint64_t td_hole_birth_enabled_txg;
63 blkptr_cb_t *td_func;
64 void *td_arg;
65 boolean_t td_realloc_possible;
66 } traverse_data_t;
67
68 static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,
69 uint64_t objset, uint64_t object);
70 static void prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *,
71 uint64_t objset, uint64_t object);
72
73 static int
74 traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
75 {
76 traverse_data_t *td = arg;
77 zbookmark_phys_t zb;
78
79 if (BP_IS_HOLE(bp))
80 return (0);
81
82 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(td->td_spa))
83 return (0);
84
85 SET_BOOKMARK(&zb, td->td_objset, ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
86 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
87
88 (void) td->td_func(td->td_spa, zilog, bp, &zb, NULL, td->td_arg);
89
90 return (0);
91 }
92
93 static int
94 traverse_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
95 {
96 traverse_data_t *td = arg;
97
98 if (lrc->lrc_txtype == TX_WRITE) {
99 lr_write_t *lr = (lr_write_t *)lrc;
100 blkptr_t *bp = &lr->lr_blkptr;
101 zbookmark_phys_t zb;
102
103 if (BP_IS_HOLE(bp))
104 return (0);
105
106 if (claim_txg == 0 || bp->blk_birth < claim_txg)
107 return (0);
108
109 SET_BOOKMARK(&zb, td->td_objset, lr->lr_foid,
110 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
111
112 (void) td->td_func(td->td_spa, zilog, bp, &zb, NULL,
113 td->td_arg);
114 }
115 return (0);
116 }
117
118 static void
119 traverse_zil(traverse_data_t *td, zil_header_t *zh)
120 {
121 uint64_t claim_txg = zh->zh_claim_txg;
122 zilog_t *zilog;
123
124 /*
125 * We only want to visit blocks that have been claimed but not yet
126 * replayed; plus, in read-only mode, blocks that are already stable.
127 */
128 if (claim_txg == 0 && spa_writeable(td->td_spa))
129 return;
130
131 zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);
132
133 (void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,
134 claim_txg);
135
136 zil_free(zilog);
137 }
138
139 typedef enum resume_skip {
140 RESUME_SKIP_ALL,
141 RESUME_SKIP_NONE,
142 RESUME_SKIP_CHILDREN
143 } resume_skip_t;
144
145 /*
146 * Returns RESUME_SKIP_ALL if td indicates that we are resuming a traversal and
147 * the block indicated by zb does not need to be visited at all. Returns
148 * RESUME_SKIP_CHILDREN if we are resuming a post traversal and we reach the
149 * resume point. This indicates that this block should be visited but not its
150 * children (since they must have been visited in a previous traversal).
151 * Otherwise returns RESUME_SKIP_NONE.
152 */
153 static resume_skip_t
154 resume_skip_check(traverse_data_t *td, const dnode_phys_t *dnp,
155 const zbookmark_phys_t *zb)
156 {
157 if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume)) {
158 /*
159 * If we already visited this bp & everything below,
160 * don't bother doing it again.
161 */
162 if (zbookmark_subtree_completed(dnp, zb, td->td_resume))
163 return (RESUME_SKIP_ALL);
164
165 /*
166 * If we found the block we're trying to resume from, zero
167 * the bookmark out to indicate that we have resumed.
168 */
169 if (bcmp(zb, td->td_resume, sizeof (*zb)) == 0) {
170 bzero(td->td_resume, sizeof (*zb));
171 if (td->td_flags & TRAVERSE_POST)
172 return (RESUME_SKIP_CHILDREN);
173 }
174 }
175 return (RESUME_SKIP_NONE);
176 }
177
178 static void
179 traverse_prefetch_metadata(traverse_data_t *td,
180 const blkptr_t *bp, const zbookmark_phys_t *zb)
181 {
182 arc_flags_t flags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
183
184 if (!(td->td_flags & TRAVERSE_PREFETCH_METADATA))
185 return;
186 /*
187 * If we are in the process of resuming, don't prefetch, because
188 * some children will not be needed (and in fact may have already
189 * been freed).
190 */
191 if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume))
192 return;
193 if (BP_IS_HOLE(bp) || bp->blk_birth <= td->td_min_txg)
194 return;
195 if (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE)
196 return;
197
198 (void) arc_read(NULL, td->td_spa, bp, NULL, NULL,
199 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
200 }
201
202 static boolean_t
203 prefetch_needed(prefetch_data_t *pfd, const blkptr_t *bp)
204 {
205 ASSERT(pfd->pd_flags & TRAVERSE_PREFETCH_DATA);
206 if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp) ||
207 BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG)
208 return (B_FALSE);
209 return (B_TRUE);
210 }
211
212 static int
213 traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
214 const blkptr_t *bp, const zbookmark_phys_t *zb)
215 {
216 zbookmark_phys_t czb;
217 int err = 0;
218 arc_buf_t *buf = NULL;
219 prefetch_data_t *pd = td->td_pfd;
220 boolean_t hard = td->td_flags & TRAVERSE_HARD;
221
222 switch (resume_skip_check(td, dnp, zb)) {
223 case RESUME_SKIP_ALL:
224 return (0);
225 case RESUME_SKIP_CHILDREN:
226 goto post;
227 case RESUME_SKIP_NONE:
228 break;
229 default:
230 ASSERT(0);
231 }
232
233 if (bp->blk_birth == 0) {
234 /*
235 * Since this block has a birth time of 0 it must be one of
236 * two things: a hole created before the
237 * SPA_FEATURE_HOLE_BIRTH feature was enabled, or a hole
238 * which has always been a hole in an object.
239 *
240 * If a file is written sparsely, then the unwritten parts of
241 * the file were "always holes" -- that is, they have been
242 * holes since this object was allocated. However, we (and
243 * our callers) can not necessarily tell when an object was
244 * allocated. Therefore, if it's possible that this object
245 * was freed and then its object number reused, we need to
246 * visit all the holes with birth==0.
247 *
248 * If it isn't possible that the object number was reused,
249 * then if SPA_FEATURE_HOLE_BIRTH was enabled before we wrote
250 * all the blocks we will visit as part of this traversal,
251 * then this hole must have always existed, so we can skip
252 * it. We visit blocks born after (exclusive) td_min_txg.
253 *
254 * Note that the meta-dnode cannot be reallocated.
255 */
256 if ((!td->td_realloc_possible ||
257 zb->zb_object == DMU_META_DNODE_OBJECT) &&
258 td->td_hole_birth_enabled_txg <= td->td_min_txg)
259 return (0);
260 } else if (bp->blk_birth <= td->td_min_txg) {
261 return (0);
262 }
263
264 if (pd != NULL && !pd->pd_exited && prefetch_needed(pd, bp)) {
265 uint64_t size = BP_GET_LSIZE(bp);
266 mutex_enter(&pd->pd_mtx);
267 ASSERT(pd->pd_bytes_fetched >= 0);
268 while (pd->pd_bytes_fetched < size && !pd->pd_exited)
269 cv_wait(&pd->pd_cv, &pd->pd_mtx);
270 pd->pd_bytes_fetched -= size;
271 cv_broadcast(&pd->pd_cv);
272 mutex_exit(&pd->pd_mtx);
273 }
274
275 if (BP_IS_HOLE(bp)) {
276 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
277 if (err != 0)
278 goto post;
279 return (0);
280 }
281
282 if (td->td_flags & TRAVERSE_PRE) {
283 err = td->td_func(td->td_spa, NULL, bp, zb, dnp,
284 td->td_arg);
285 if (err == TRAVERSE_VISIT_NO_CHILDREN)
286 return (0);
287 if (err != 0)
288 goto post;
289 }
290
291 if (BP_GET_LEVEL(bp) > 0) {
292 arc_flags_t flags = ARC_FLAG_WAIT;
293 int i;
294 blkptr_t *cbp;
295 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
296
297 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
298 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
299 if (err != 0)
300 goto post;
301 cbp = buf->b_data;
302
303 for (i = 0; i < epb; i++) {
304 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
305 zb->zb_level - 1,
306 zb->zb_blkid * epb + i);
307 traverse_prefetch_metadata(td, &cbp[i], &czb);
308 }
309
310 /* recursively visitbp() blocks below this */
311 for (i = 0; i < epb; i++) {
312 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
313 zb->zb_level - 1,
314 zb->zb_blkid * epb + i);
315 err = traverse_visitbp(td, dnp, &cbp[i], &czb);
316 if (err != 0)
317 break;
318 }
319 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
320 arc_flags_t flags = ARC_FLAG_WAIT;
321 int i;
322 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
323
324 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
325 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
326 if (err != 0)
327 goto post;
328 dnode_phys_t *child_dnp = buf->b_data;
329
330 for (i = 0; i < epb; i++) {
331 prefetch_dnode_metadata(td, &child_dnp[i],
332 zb->zb_objset, zb->zb_blkid * epb + i);
333 }
334
335 /* recursively visitbp() blocks below this */
336 for (i = 0; i < epb; i++) {
337 err = traverse_dnode(td, &child_dnp[i],
338 zb->zb_objset, zb->zb_blkid * epb + i);
339 if (err != 0)
340 break;
341 }
342 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
343 arc_flags_t flags = ARC_FLAG_WAIT;
344
345 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
346 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
347 if (err != 0)
348 goto post;
349
350 objset_phys_t *osp = buf->b_data;
351 prefetch_dnode_metadata(td, &osp->os_meta_dnode, zb->zb_objset,
352 DMU_META_DNODE_OBJECT);
353 /*
354 * See the block comment above for the goal of this variable.
355 * If the maxblkid of the meta-dnode is 0, then we know that
356 * we've never had more than DNODES_PER_BLOCK objects in the
357 * dataset, which means we can't have reused any object ids.
358 */
359 if (osp->os_meta_dnode.dn_maxblkid == 0)
360 td->td_realloc_possible = B_FALSE;
361
362 if (arc_buf_size(buf) >= sizeof (objset_phys_t)) {
363 prefetch_dnode_metadata(td, &osp->os_groupused_dnode,
364 zb->zb_objset, DMU_GROUPUSED_OBJECT);
365 prefetch_dnode_metadata(td, &osp->os_userused_dnode,
366 zb->zb_objset, DMU_USERUSED_OBJECT);
367 }
368
369 err = traverse_dnode(td, &osp->os_meta_dnode, zb->zb_objset,
370 DMU_META_DNODE_OBJECT);
371 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
372 err = traverse_dnode(td, &osp->os_groupused_dnode,
373 zb->zb_objset, DMU_GROUPUSED_OBJECT);
374 }
375 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
376 err = traverse_dnode(td, &osp->os_userused_dnode,
377 zb->zb_objset, DMU_USERUSED_OBJECT);
378 }
379 }
380
381 if (buf)
382 (void) arc_buf_remove_ref(buf, &buf);
383
384 post:
385 if (err == 0 && (td->td_flags & TRAVERSE_POST))
386 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
387
388 if (hard && (err == EIO || err == ECKSUM)) {
389 /*
390 * Ignore this disk error as requested by the HARD flag,
391 * and continue traversal.
392 */
393 err = 0;
394 }
395
396 /*
397 * If we are stopping here, set td_resume.
398 */
399 if (td->td_resume != NULL && err != 0 && !td->td_paused) {
400 td->td_resume->zb_objset = zb->zb_objset;
401 td->td_resume->zb_object = zb->zb_object;
402 td->td_resume->zb_level = 0;
403 /*
404 * If we have stopped on an indirect block (e.g. due to
405 * i/o error), we have not visited anything below it.
406 * Set the bookmark to the first level-0 block that we need
407 * to visit. This way, the resuming code does not need to
408 * deal with resuming from indirect blocks.
409 *
410 * Note, if zb_level <= 0, dnp may be NULL, so we don't want
411 * to dereference it.
412 */
413 td->td_resume->zb_blkid = zb->zb_blkid;
414 if (zb->zb_level > 0) {
415 td->td_resume->zb_blkid <<= zb->zb_level *
416 (dnp->dn_indblkshift - SPA_BLKPTRSHIFT);
417 }
418 td->td_paused = B_TRUE;
419 }
420
421 return (err);
422 }
423
424 static void
425 prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *dnp,
426 uint64_t objset, uint64_t object)
427 {
428 int j;
429 zbookmark_phys_t czb;
430
431 for (j = 0; j < dnp->dn_nblkptr; j++) {
432 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
433 traverse_prefetch_metadata(td, &dnp->dn_blkptr[j], &czb);
434 }
435
436 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
437 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
438 traverse_prefetch_metadata(td, &dnp->dn_spill, &czb);
439 }
440 }
441
442 static int
443 traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,
444 uint64_t objset, uint64_t object)
445 {
446 int j, err = 0;
447 zbookmark_phys_t czb;
448
449 if (object != DMU_META_DNODE_OBJECT && td->td_resume != NULL &&
450 object < td->td_resume->zb_object)
451 return (0);
452
453 if (td->td_flags & TRAVERSE_PRE) {
454 SET_BOOKMARK(&czb, objset, object, ZB_DNODE_LEVEL,
455 ZB_DNODE_BLKID);
456 err = td->td_func(td->td_spa, NULL, NULL, &czb, dnp,
457 td->td_arg);
458 if (err == TRAVERSE_VISIT_NO_CHILDREN)
459 return (0);
460 if (err != 0)
461 return (err);
462 }
463
464 for (j = 0; j < dnp->dn_nblkptr; j++) {
465 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
466 err = traverse_visitbp(td, dnp, &dnp->dn_blkptr[j], &czb);
467 if (err != 0)
468 break;
469 }
470
471 if (err == 0 && (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)) {
472 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
473 err = traverse_visitbp(td, dnp, &dnp->dn_spill, &czb);
474 }
475
476 if (err == 0 && (td->td_flags & TRAVERSE_POST)) {
477 SET_BOOKMARK(&czb, objset, object, ZB_DNODE_LEVEL,
478 ZB_DNODE_BLKID);
479 err = td->td_func(td->td_spa, NULL, NULL, &czb, dnp,
480 td->td_arg);
481 if (err == TRAVERSE_VISIT_NO_CHILDREN)
482 return (0);
483 if (err != 0)
484 return (err);
485 }
486 return (err);
487 }
488
489 /* ARGSUSED */
490 static int
491 traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
492 const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
493 {
494 prefetch_data_t *pfd = arg;
495 arc_flags_t aflags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
496
497 ASSERT(pfd->pd_bytes_fetched >= 0);
498 if (bp == NULL)
499 return (0);
500 if (pfd->pd_cancel)
501 return (SET_ERROR(EINTR));
502
503 if (!prefetch_needed(pfd, bp))
504 return (0);
505
506 mutex_enter(&pfd->pd_mtx);
507 while (!pfd->pd_cancel && pfd->pd_bytes_fetched >= zfs_pd_bytes_max)
508 cv_wait(&pfd->pd_cv, &pfd->pd_mtx);
509 pfd->pd_bytes_fetched += BP_GET_LSIZE(bp);
510 cv_broadcast(&pfd->pd_cv);
511 mutex_exit(&pfd->pd_mtx);
512
513 (void) arc_read(NULL, spa, bp, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
514 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, &aflags, zb);
515
516 return (0);
517 }
518
519 static void
520 traverse_prefetch_thread(void *arg)
521 {
522 traverse_data_t *td_main = arg;
523 traverse_data_t td = *td_main;
524 zbookmark_phys_t czb;
525
526 td.td_func = traverse_prefetcher;
527 td.td_arg = td_main->td_pfd;
528 td.td_pfd = NULL;
529 td.td_resume = &td_main->td_pfd->pd_resume;
530
531 SET_BOOKMARK(&czb, td.td_objset,
532 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
533 (void) traverse_visitbp(&td, NULL, td.td_rootbp, &czb);
534
535 mutex_enter(&td_main->td_pfd->pd_mtx);
536 td_main->td_pfd->pd_exited = B_TRUE;
537 cv_broadcast(&td_main->td_pfd->pd_cv);
538 mutex_exit(&td_main->td_pfd->pd_mtx);
539 }
540
541 /*
542 * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
543 * in syncing context).
544 */
545 static int
546 traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
547 uint64_t txg_start, zbookmark_phys_t *resume, int flags,
548 blkptr_cb_t func, void *arg)
549 {
550 traverse_data_t td;
551 prefetch_data_t pd = { 0 };
552 zbookmark_phys_t czb;
553 int err;
554
555 ASSERT(ds == NULL || objset == ds->ds_object);
556 ASSERT(!(flags & TRAVERSE_PRE) || !(flags & TRAVERSE_POST));
557
558 td.td_spa = spa;
559 td.td_objset = objset;
560 td.td_rootbp = rootbp;
561 td.td_min_txg = txg_start;
562 td.td_resume = resume;
563 td.td_func = func;
564 td.td_arg = arg;
565 td.td_pfd = &pd;
566 td.td_flags = flags;
567 td.td_paused = B_FALSE;
568 td.td_realloc_possible = (txg_start == 0 ? B_FALSE : B_TRUE);
569
570 if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
571 VERIFY(spa_feature_enabled_txg(spa,
572 SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg));
573 } else {
574 td.td_hole_birth_enabled_txg = UINT64_MAX;
575 }
576
577 pd.pd_flags = flags;
578 if (resume != NULL)
579 pd.pd_resume = *resume;
580 mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);
581 cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL);
582
583 /* See comment on ZIL traversal in dsl_scan_visitds. */
584 if (ds != NULL && !ds->ds_is_snapshot && !BP_IS_HOLE(rootbp)) {
585 arc_flags_t flags = ARC_FLAG_WAIT;
586 objset_phys_t *osp;
587 arc_buf_t *buf;
588
589 err = arc_read(NULL, td.td_spa, rootbp,
590 arc_getbuf_func, &buf,
591 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, NULL);
592 if (err != 0)
593 return (err);
594
595 osp = buf->b_data;
596 traverse_zil(&td, &osp->os_zil_header);
597 (void) arc_buf_remove_ref(buf, &buf);
598 }
599
600 if (!(flags & TRAVERSE_PREFETCH_DATA) ||
601 0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,
602 &td, TQ_NOQUEUE))
603 pd.pd_exited = B_TRUE;
604
605 SET_BOOKMARK(&czb, td.td_objset,
606 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
607 err = traverse_visitbp(&td, NULL, rootbp, &czb);
608
609 mutex_enter(&pd.pd_mtx);
610 pd.pd_cancel = B_TRUE;
611 cv_broadcast(&pd.pd_cv);
612 while (!pd.pd_exited)
613 cv_wait(&pd.pd_cv, &pd.pd_mtx);
614 mutex_exit(&pd.pd_mtx);
615
616 mutex_destroy(&pd.pd_mtx);
617 cv_destroy(&pd.pd_cv);
618
619 return (err);
620 }
621
622 /*
623 * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
624 * in syncing context).
625 */
626 int
627 traverse_dataset_resume(dsl_dataset_t *ds, uint64_t txg_start,
628 zbookmark_phys_t *resume,
629 int flags, blkptr_cb_t func, void *arg)
630 {
631 return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds, ds->ds_object,
632 &dsl_dataset_phys(ds)->ds_bp, txg_start, resume, flags, func, arg));
633 }
634
635 int
636 traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start,
637 int flags, blkptr_cb_t func, void *arg)
638 {
639 return (traverse_dataset_resume(ds, txg_start, NULL, flags, func, arg));
640 }
641
642 int
643 traverse_dataset_destroyed(spa_t *spa, blkptr_t *blkptr,
644 uint64_t txg_start, zbookmark_phys_t *resume, int flags,
645 blkptr_cb_t func, void *arg)
646 {
647 return (traverse_impl(spa, NULL, ZB_DESTROYED_OBJSET,
648 blkptr, txg_start, resume, flags, func, arg));
649 }
650
651 /*
652 * NB: pool must not be changing on-disk (eg, from zdb or sync context).
653 */
654 int
655 traverse_pool(spa_t *spa, uint64_t txg_start, int flags,
656 blkptr_cb_t func, void *arg)
657 {
658 int err;
659 dsl_pool_t *dp = spa_get_dsl(spa);
660 objset_t *mos = dp->dp_meta_objset;
661 boolean_t hard = (flags & TRAVERSE_HARD);
662
663 /* visit the MOS */
664 err = traverse_impl(spa, NULL, 0, spa_get_rootblkptr(spa),
665 txg_start, NULL, flags, func, arg);
666 if (err != 0)
667 return (err);
668
669 /* visit each dataset */
670 for (uint64_t obj = 1; err == 0;
671 err = dmu_object_next(mos, &obj, B_FALSE, txg_start)) {
672 dmu_object_info_t doi;
673
674 err = dmu_object_info(mos, obj, &doi);
675 if (err != 0) {
676 if (hard)
677 continue;
678 break;
679 }
680
681 if (doi.doi_bonus_type == DMU_OT_DSL_DATASET) {
682 dsl_dataset_t *ds;
683 uint64_t txg = txg_start;
684
685 dsl_pool_config_enter(dp, FTAG);
686 err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
687 dsl_pool_config_exit(dp, FTAG);
688 if (err != 0) {
689 if (hard)
690 continue;
691 break;
692 }
693 if (dsl_dataset_phys(ds)->ds_prev_snap_txg > txg)
694 txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
695 err = traverse_dataset(ds, txg, flags, func, arg);
696 dsl_dataset_rele(ds, FTAG);
697 if (err != 0)
698 break;
699 }
700 }
701 if (err == ESRCH)
702 err = 0;
703 return (err);
704 }