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 && !ds->ds_is_snapshot && !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 } 649