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, 2014 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 int zfs_pd_blks_max = 100;
42
43 typedef struct prefetch_data {
44 kmutex_t pd_mtx;
45 kcondvar_t pd_cv;
46 int pd_blks_max;
47 int pd_blks_fetched;
48 int pd_flags;
49 boolean_t pd_cancel;
50 boolean_t pd_exited;
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 } traverse_data_t;
66
67 static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,
68 uint64_t objset, uint64_t object);
69 static void prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *,
70 uint64_t objset, uint64_t object);
71
72 static int
73 traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
74 {
75 traverse_data_t *td = arg;
76 zbookmark_phys_t zb;
77
78 if (BP_IS_HOLE(bp))
79 return (0);
80
81 if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(td->td_spa))
82 return (0);
83
84 SET_BOOKMARK(&zb, td->td_objset, ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
85 bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
86
87 (void) td->td_func(td->td_spa, zilog, bp, &zb, NULL, td->td_arg);
88
89 return (0);
90 }
91
92 static int
93 traverse_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
94 {
95 traverse_data_t *td = arg;
96
97 if (lrc->lrc_txtype == TX_WRITE) {
98 lr_write_t *lr = (lr_write_t *)lrc;
99 blkptr_t *bp = &lr->lr_blkptr;
100 zbookmark_phys_t zb;
101
102 if (BP_IS_HOLE(bp))
103 return (0);
104
105 if (claim_txg == 0 || bp->blk_birth < claim_txg)
106 return (0);
107
108 SET_BOOKMARK(&zb, td->td_objset, lr->lr_foid,
109 ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
110
111 (void) td->td_func(td->td_spa, zilog, bp, &zb, NULL,
112 td->td_arg);
113 }
114 return (0);
115 }
116
117 static void
118 traverse_zil(traverse_data_t *td, zil_header_t *zh)
119 {
120 uint64_t claim_txg = zh->zh_claim_txg;
121 zilog_t *zilog;
122
123 /*
124 * We only want to visit blocks that have been claimed but not yet
125 * replayed; plus, in read-only mode, blocks that are already stable.
126 */
127 if (claim_txg == 0 && spa_writeable(td->td_spa))
128 return;
129
130 zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);
131
132 (void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,
133 claim_txg);
134
135 zil_free(zilog);
136 }
137
138 typedef enum resume_skip {
139 RESUME_SKIP_ALL,
140 RESUME_SKIP_NONE,
141 RESUME_SKIP_CHILDREN
142 } resume_skip_t;
143
144 /*
145 * Returns RESUME_SKIP_ALL if td indicates that we are resuming a traversal and
146 * the block indicated by zb does not need to be visited at all. Returns
147 * RESUME_SKIP_CHILDREN if we are resuming a post traversal and we reach the
148 * resume point. This indicates that this block should be visited but not its
149 * children (since they must have been visited in a previous traversal).
150 * Otherwise returns RESUME_SKIP_NONE.
151 */
152 static resume_skip_t
153 resume_skip_check(traverse_data_t *td, const dnode_phys_t *dnp,
154 const zbookmark_phys_t *zb)
155 {
156 if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume)) {
157 /*
158 * If we already visited this bp & everything below,
159 * don't bother doing it again.
160 */
161 if (zbookmark_is_before(dnp, zb, td->td_resume))
162 return (RESUME_SKIP_ALL);
163
164 /*
165 * If we found the block we're trying to resume from, zero
166 * the bookmark out to indicate that we have resumed.
167 */
168 if (bcmp(zb, td->td_resume, sizeof (*zb)) == 0) {
169 bzero(td->td_resume, sizeof (*zb));
170 if (td->td_flags & TRAVERSE_POST)
171 return (RESUME_SKIP_CHILDREN);
172 }
173 }
174 return (RESUME_SKIP_NONE);
175 }
176
177 static void
178 traverse_prefetch_metadata(traverse_data_t *td,
179 const blkptr_t *bp, const zbookmark_phys_t *zb)
180 {
181 arc_flags_t flags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
182
183 if (!(td->td_flags & TRAVERSE_PREFETCH_METADATA))
184 return;
185 /*
186 * If we are in the process of resuming, don't prefetch, because
187 * some children will not be needed (and in fact may have already
188 * been freed).
189 */
190 if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume))
191 return;
192 if (BP_IS_HOLE(bp) || bp->blk_birth <= td->td_min_txg)
193 return;
194 if (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE)
195 return;
196
197 (void) arc_read(NULL, td->td_spa, bp, NULL, NULL,
198 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
199 }
200
201 static boolean_t
202 prefetch_needed(prefetch_data_t *pfd, const blkptr_t *bp)
203 {
204 ASSERT(pfd->pd_flags & TRAVERSE_PREFETCH_DATA);
205 if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp) ||
206 BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG)
207 return (B_FALSE);
208 return (B_TRUE);
209 }
210
211 static int
212 traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
213 const blkptr_t *bp, const zbookmark_phys_t *zb)
214 {
215 zbookmark_phys_t czb;
216 int err = 0;
217 arc_buf_t *buf = NULL;
218 prefetch_data_t *pd = td->td_pfd;
219 boolean_t hard = td->td_flags & TRAVERSE_HARD;
220
221 switch (resume_skip_check(td, dnp, zb)) {
222 case RESUME_SKIP_ALL:
223 return (0);
224 case RESUME_SKIP_CHILDREN:
225 goto post;
226 case RESUME_SKIP_NONE:
227 break;
228 default:
229 ASSERT(0);
230 }
231
232 if (bp->blk_birth == 0) {
233 /*
234 * Since this block has a birth time of 0 it must be a
235 * hole created before the SPA_FEATURE_HOLE_BIRTH
236 * feature was enabled. If SPA_FEATURE_HOLE_BIRTH
237 * was enabled before the min_txg for this traveral we
238 * know the hole must have been created before the
239 * min_txg for this traveral, so we can skip it. If
240 * SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg
241 * for this traveral we cannot tell if the hole was
242 * created before or after the min_txg for this
243 * traversal, so we cannot skip it.
244 */
245 if (td->td_hole_birth_enabled_txg < td->td_min_txg)
246 return (0);
247 } else if (bp->blk_birth <= td->td_min_txg) {
248 return (0);
249 }
250
251 if (pd != NULL && !pd->pd_exited && prefetch_needed(pd, bp)) {
252 mutex_enter(&pd->pd_mtx);
253 ASSERT(pd->pd_blks_fetched >= 0);
254 while (pd->pd_blks_fetched == 0 && !pd->pd_exited)
255 cv_wait(&pd->pd_cv, &pd->pd_mtx);
256 pd->pd_blks_fetched--;
257 cv_broadcast(&pd->pd_cv);
258 mutex_exit(&pd->pd_mtx);
259 }
260
261 if (BP_IS_HOLE(bp)) {
262 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
263 if (err != 0)
264 goto post;
265 return (0);
266 }
267
268 if (td->td_flags & TRAVERSE_PRE) {
269 err = td->td_func(td->td_spa, NULL, bp, zb, dnp,
270 td->td_arg);
271 if (err == TRAVERSE_VISIT_NO_CHILDREN)
272 return (0);
273 if (err != 0)
274 goto post;
275 }
276
277 if (BP_GET_LEVEL(bp) > 0) {
278 arc_flags_t flags = ARC_FLAG_WAIT;
279 int i;
280 blkptr_t *cbp;
281 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
282
283 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
284 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
285 if (err != 0)
286 goto post;
287 cbp = buf->b_data;
288
289 for (i = 0; i < epb; i++) {
290 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
291 zb->zb_level - 1,
292 zb->zb_blkid * epb + i);
293 traverse_prefetch_metadata(td, &cbp[i], &czb);
294 }
295
296 /* recursively visitbp() blocks below this */
297 for (i = 0; i < epb; i++) {
298 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
299 zb->zb_level - 1,
300 zb->zb_blkid * epb + i);
301 err = traverse_visitbp(td, dnp, &cbp[i], &czb);
302 if (err != 0)
303 break;
304 }
305 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
306 arc_flags_t flags = ARC_FLAG_WAIT;
307 int i;
308 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
309
310 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
311 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
312 if (err != 0)
313 goto post;
314 dnp = buf->b_data;
315
316 for (i = 0; i < epb; i++) {
317 prefetch_dnode_metadata(td, &dnp[i], zb->zb_objset,
318 zb->zb_blkid * epb + i);
319 }
320
321 /* recursively visitbp() blocks below this */
322 for (i = 0; i < epb; i++) {
323 err = traverse_dnode(td, &dnp[i], zb->zb_objset,
324 zb->zb_blkid * epb + i);
325 if (err != 0)
326 break;
327 }
328 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
329 arc_flags_t flags = ARC_FLAG_WAIT;
330 objset_phys_t *osp;
331 dnode_phys_t *dnp;
332
333 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
334 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
335 if (err != 0)
336 goto post;
337
338 osp = buf->b_data;
339 dnp = &osp->os_meta_dnode;
340 prefetch_dnode_metadata(td, dnp, zb->zb_objset,
341 DMU_META_DNODE_OBJECT);
342 if (arc_buf_size(buf) >= sizeof (objset_phys_t)) {
343 prefetch_dnode_metadata(td, &osp->os_groupused_dnode,
344 zb->zb_objset, DMU_GROUPUSED_OBJECT);
345 prefetch_dnode_metadata(td, &osp->os_userused_dnode,
346 zb->zb_objset, DMU_USERUSED_OBJECT);
347 }
348
349 err = traverse_dnode(td, dnp, zb->zb_objset,
350 DMU_META_DNODE_OBJECT);
351 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
352 dnp = &osp->os_groupused_dnode;
353 err = traverse_dnode(td, dnp, zb->zb_objset,
354 DMU_GROUPUSED_OBJECT);
355 }
356 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
357 dnp = &osp->os_userused_dnode;
358 err = traverse_dnode(td, dnp, zb->zb_objset,
359 DMU_USERUSED_OBJECT);
360 }
361 }
362
363 if (buf)
364 (void) arc_buf_remove_ref(buf, &buf);
365
366 post:
367 if (err == 0 && (td->td_flags & TRAVERSE_POST))
368 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
369
370 if (hard && (err == EIO || err == ECKSUM)) {
371 /*
372 * Ignore this disk error as requested by the HARD flag,
373 * and continue traversal.
374 */
375 err = 0;
376 }
377
378 /*
379 * If we are stopping here, set td_resume.
380 */
381 if (td->td_resume != NULL && err != 0 && !td->td_paused) {
382 td->td_resume->zb_objset = zb->zb_objset;
383 td->td_resume->zb_object = zb->zb_object;
384 td->td_resume->zb_level = 0;
385 /*
386 * If we have stopped on an indirect block (e.g. due to
387 * i/o error), we have not visited anything below it.
388 * Set the bookmark to the first level-0 block that we need
389 * to visit. This way, the resuming code does not need to
390 * deal with resuming from indirect blocks.
391 */
392 td->td_resume->zb_blkid = zb->zb_blkid <<
393 (zb->zb_level * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT));
394 td->td_paused = B_TRUE;
395 }
396
397 return (err);
398 }
399
400 static void
401 prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *dnp,
402 uint64_t objset, uint64_t object)
403 {
404 int j;
405 zbookmark_phys_t czb;
406
407 for (j = 0; j < dnp->dn_nblkptr; j++) {
408 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
409 traverse_prefetch_metadata(td, &dnp->dn_blkptr[j], &czb);
410 }
411
412 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
413 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
414 traverse_prefetch_metadata(td, &dnp->dn_spill, &czb);
415 }
416 }
417
418 static int
419 traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,
420 uint64_t objset, uint64_t object)
421 {
422 int j, err = 0;
423 zbookmark_phys_t czb;
424
425 for (j = 0; j < dnp->dn_nblkptr; j++) {
426 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
427 err = traverse_visitbp(td, dnp, &dnp->dn_blkptr[j], &czb);
428 if (err != 0)
429 break;
430 }
431
432 if (err == 0 && dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
433 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
434 err = traverse_visitbp(td, dnp, &dnp->dn_spill, &czb);
435 }
436 return (err);
437 }
438
439 /* ARGSUSED */
440 static int
441 traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
442 const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
443 {
444 prefetch_data_t *pfd = arg;
445 arc_flags_t aflags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH;
446
447 ASSERT(pfd->pd_blks_fetched >= 0);
448 if (pfd->pd_cancel)
449 return (SET_ERROR(EINTR));
450
451 if (!prefetch_needed(pfd, bp))
452 return (0);
453
454 mutex_enter(&pfd->pd_mtx);
455 while (!pfd->pd_cancel && pfd->pd_blks_fetched >= pfd->pd_blks_max)
456 cv_wait(&pfd->pd_cv, &pfd->pd_mtx);
457 pfd->pd_blks_fetched++;
458 cv_broadcast(&pfd->pd_cv);
459 mutex_exit(&pfd->pd_mtx);
460
461 (void) arc_read(NULL, spa, bp, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
462 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, &aflags, zb);
463
464 return (0);
465 }
466
467 static void
468 traverse_prefetch_thread(void *arg)
469 {
470 traverse_data_t *td_main = arg;
471 traverse_data_t td = *td_main;
472 zbookmark_phys_t czb;
473
474 td.td_func = traverse_prefetcher;
475 td.td_arg = td_main->td_pfd;
476 td.td_pfd = NULL;
477
478 SET_BOOKMARK(&czb, td.td_objset,
479 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
480 (void) traverse_visitbp(&td, NULL, td.td_rootbp, &czb);
481
482 mutex_enter(&td_main->td_pfd->pd_mtx);
483 td_main->td_pfd->pd_exited = B_TRUE;
484 cv_broadcast(&td_main->td_pfd->pd_cv);
485 mutex_exit(&td_main->td_pfd->pd_mtx);
486 }
487
488 /*
489 * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
490 * in syncing context).
491 */
492 static int
493 traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
494 uint64_t txg_start, zbookmark_phys_t *resume, int flags,
495 blkptr_cb_t func, void *arg)
496 {
497 traverse_data_t td;
498 prefetch_data_t pd = { 0 };
499 zbookmark_phys_t czb;
500 int err;
501
502 ASSERT(ds == NULL || objset == ds->ds_object);
503 ASSERT(!(flags & TRAVERSE_PRE) || !(flags & TRAVERSE_POST));
504
505 /*
506 * The data prefetching mechanism (the prefetch thread) is incompatible
507 * with resuming from a bookmark.
508 */
509 ASSERT(resume == NULL || !(flags & TRAVERSE_PREFETCH_DATA));
510
511 td.td_spa = spa;
512 td.td_objset = objset;
513 td.td_rootbp = rootbp;
514 td.td_min_txg = txg_start;
515 td.td_resume = resume;
516 td.td_func = func;
517 td.td_arg = arg;
518 td.td_pfd = &pd;
519 td.td_flags = flags;
520 td.td_paused = B_FALSE;
521
522 if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) {
523 VERIFY(spa_feature_enabled_txg(spa,
524 SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg));
525 } else {
526 td.td_hole_birth_enabled_txg = 0;
527 }
528
529 pd.pd_blks_max = zfs_pd_blks_max;
530 pd.pd_flags = flags;
531 mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);
532 cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL);
533
534 /* See comment on ZIL traversal in dsl_scan_visitds. */
535 if (ds != NULL && !dsl_dataset_is_snapshot(ds) && !BP_IS_HOLE(rootbp)) {
536 arc_flags_t flags = ARC_FLAG_WAIT;
537 objset_phys_t *osp;
538 arc_buf_t *buf;
539
540 err = arc_read(NULL, td.td_spa, rootbp,
541 arc_getbuf_func, &buf,
542 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, NULL);
543 if (err != 0)
544 return (err);
545
546 osp = buf->b_data;
547 traverse_zil(&td, &osp->os_zil_header);
548 (void) arc_buf_remove_ref(buf, &buf);
549 }
550
551 if (!(flags & TRAVERSE_PREFETCH_DATA) ||
552 0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,
553 &td, TQ_NOQUEUE))
554 pd.pd_exited = B_TRUE;
555
556 SET_BOOKMARK(&czb, td.td_objset,
557 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
558 err = traverse_visitbp(&td, NULL, rootbp, &czb);
559
560 mutex_enter(&pd.pd_mtx);
561 pd.pd_cancel = B_TRUE;
562 cv_broadcast(&pd.pd_cv);
563 while (!pd.pd_exited)
564 cv_wait(&pd.pd_cv, &pd.pd_mtx);
565 mutex_exit(&pd.pd_mtx);
566
567 mutex_destroy(&pd.pd_mtx);
568 cv_destroy(&pd.pd_cv);
569
570 return (err);
571 }
572
573 /*
574 * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
575 * in syncing context).
576 */
577 int
578 traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start, int flags,
579 blkptr_cb_t func, void *arg)
580 {
581 return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds, ds->ds_object,
582 &dsl_dataset_phys(ds)->ds_bp, txg_start, NULL, flags, func, arg));
583 }
584
585 int
586 traverse_dataset_destroyed(spa_t *spa, blkptr_t *blkptr,
587 uint64_t txg_start, zbookmark_phys_t *resume, int flags,
588 blkptr_cb_t func, void *arg)
589 {
590 return (traverse_impl(spa, NULL, ZB_DESTROYED_OBJSET,
591 blkptr, txg_start, resume, flags, func, arg));
592 }
593
594 /*
595 * NB: pool must not be changing on-disk (eg, from zdb or sync context).
596 */
597 int
598 traverse_pool(spa_t *spa, uint64_t txg_start, int flags,
599 blkptr_cb_t func, void *arg)
600 {
601 int err;
602 uint64_t obj;
603 dsl_pool_t *dp = spa_get_dsl(spa);
604 objset_t *mos = dp->dp_meta_objset;
605 boolean_t hard = (flags & TRAVERSE_HARD);
606
607 /* visit the MOS */
608 err = traverse_impl(spa, NULL, 0, spa_get_rootblkptr(spa),
609 txg_start, NULL, flags, func, arg);
610 if (err != 0)
611 return (err);
612
613 /* visit each dataset */
614 for (obj = 1; err == 0;
615 err = dmu_object_next(mos, &obj, FALSE, txg_start)) {
616 dmu_object_info_t doi;
617
618 err = dmu_object_info(mos, obj, &doi);
619 if (err != 0) {
620 if (hard)
621 continue;
622 break;
623 }
624
625 if (doi.doi_bonus_type == DMU_OT_DSL_DATASET) {
626 dsl_dataset_t *ds;
627 uint64_t txg = txg_start;
628
629 dsl_pool_config_enter(dp, FTAG);
630 err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
631 dsl_pool_config_exit(dp, FTAG);
632 if (err != 0) {
633 if (hard)
634 continue;
635 break;
636 }
637 if (dsl_dataset_phys(ds)->ds_prev_snap_txg > txg)
638 txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
639 err = traverse_dataset(ds, txg, flags, func, arg);
640 dsl_dataset_rele(ds, FTAG);
641 if (err != 0)
642 break;
643 }
644 }
645 if (err == ESRCH)
646 err = 0;
647 return (err);
648 }