dmu_traverse.c revision 282995
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 * Copyright (c) 2015 Chunwei Chen. All rights reserved. 25 */ 26 27#include <sys/zfs_context.h> 28#include <sys/dmu_objset.h> 29#include <sys/dmu_traverse.h> 30#include <sys/dsl_dataset.h> 31#include <sys/dsl_dir.h> 32#include <sys/dsl_pool.h> 33#include <sys/dnode.h> 34#include <sys/spa.h> 35#include <sys/zio.h> 36#include <sys/dmu_impl.h> 37#include <sys/sa.h> 38#include <sys/sa_impl.h> 39#include <sys/callb.h> 40#include <sys/zfeature.h> 41 42int zfs_pd_blks_max = 100; 43 44typedef struct prefetch_data { 45 kmutex_t pd_mtx; 46 kcondvar_t pd_cv; 47 int pd_blks_max; 48 int pd_blks_fetched; 49 int pd_flags; 50 boolean_t pd_cancel; 51 boolean_t pd_exited; 52} prefetch_data_t; 53 54typedef struct traverse_data { 55 spa_t *td_spa; 56 uint64_t td_objset; 57 blkptr_t *td_rootbp; 58 uint64_t td_min_txg; 59 zbookmark_phys_t *td_resume; 60 int td_flags; 61 prefetch_data_t *td_pfd; 62 boolean_t td_paused; 63 uint64_t td_hole_birth_enabled_txg; 64 blkptr_cb_t *td_func; 65 void *td_arg; 66} traverse_data_t; 67 68static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp, 69 uint64_t objset, uint64_t object); 70static void prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *, 71 uint64_t objset, uint64_t object); 72 73static int 74traverse_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 93static int 94traverse_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 118static void 119traverse_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 139typedef 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 */ 153static resume_skip_t 154resume_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_is_before(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 178static void 179traverse_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 202static boolean_t 203prefetch_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 212static int 213traverse_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 a 236 * hole created before the SPA_FEATURE_HOLE_BIRTH 237 * feature was enabled. If SPA_FEATURE_HOLE_BIRTH 238 * was enabled before the min_txg for this traveral we 239 * know the hole must have been created before the 240 * min_txg for this traveral, so we can skip it. If 241 * SPA_FEATURE_HOLE_BIRTH was enabled after the min_txg 242 * for this traveral we cannot tell if the hole was 243 * created before or after the min_txg for this 244 * traversal, so we cannot skip it. 245 */ 246 if (td->td_hole_birth_enabled_txg < td->td_min_txg) 247 return (0); 248 } else if (bp->blk_birth <= td->td_min_txg) { 249 return (0); 250 } 251 252 if (pd != NULL && !pd->pd_exited && prefetch_needed(pd, bp)) { 253 mutex_enter(&pd->pd_mtx); 254 ASSERT(pd->pd_blks_fetched >= 0); 255 while (pd->pd_blks_fetched == 0 && !pd->pd_exited) 256 cv_wait(&pd->pd_cv, &pd->pd_mtx); 257 pd->pd_blks_fetched--; 258 cv_broadcast(&pd->pd_cv); 259 mutex_exit(&pd->pd_mtx); 260 } 261 262 if (BP_IS_HOLE(bp)) { 263 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg); 264 if (err != 0) 265 goto post; 266 return (0); 267 } 268 269 if (td->td_flags & TRAVERSE_PRE) { 270 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, 271 td->td_arg); 272 if (err == TRAVERSE_VISIT_NO_CHILDREN) 273 return (0); 274 if (err != 0) 275 goto post; 276 } 277 278 if (BP_GET_LEVEL(bp) > 0) { 279 arc_flags_t flags = ARC_FLAG_WAIT; 280 int i; 281 blkptr_t *cbp; 282 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT; 283 284 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf, 285 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); 286 if (err != 0) 287 goto post; 288 cbp = buf->b_data; 289 290 for (i = 0; i < epb; i++) { 291 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object, 292 zb->zb_level - 1, 293 zb->zb_blkid * epb + i); 294 traverse_prefetch_metadata(td, &cbp[i], &czb); 295 } 296 297 /* recursively visitbp() blocks below this */ 298 for (i = 0; i < epb; i++) { 299 SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object, 300 zb->zb_level - 1, 301 zb->zb_blkid * epb + i); 302 err = traverse_visitbp(td, dnp, &cbp[i], &czb); 303 if (err != 0) 304 break; 305 } 306 } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) { 307 arc_flags_t flags = ARC_FLAG_WAIT; 308 int i; 309 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT; 310 dnode_phys_t *cdnp; 311 312 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf, 313 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); 314 if (err != 0) 315 goto post; 316 cdnp = buf->b_data; 317 318 for (i = 0; i < epb; i++) { 319 prefetch_dnode_metadata(td, &cdnp[i], zb->zb_objset, 320 zb->zb_blkid * epb + i); 321 } 322 323 /* recursively visitbp() blocks below this */ 324 for (i = 0; i < epb; i++) { 325 err = traverse_dnode(td, &cdnp[i], zb->zb_objset, 326 zb->zb_blkid * epb + i); 327 if (err != 0) 328 break; 329 } 330 } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) { 331 arc_flags_t flags = ARC_FLAG_WAIT; 332 objset_phys_t *osp; 333 dnode_phys_t *mdnp, *gdnp, *udnp; 334 335 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf, 336 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb); 337 if (err != 0) 338 goto post; 339 340 osp = buf->b_data; 341 mdnp = &osp->os_meta_dnode; 342 gdnp = &osp->os_groupused_dnode; 343 udnp = &osp->os_userused_dnode; 344 345 prefetch_dnode_metadata(td, mdnp, zb->zb_objset, 346 DMU_META_DNODE_OBJECT); 347 if (arc_buf_size(buf) >= sizeof (objset_phys_t)) { 348 prefetch_dnode_metadata(td, gdnp, zb->zb_objset, 349 DMU_GROUPUSED_OBJECT); 350 prefetch_dnode_metadata(td, udnp, zb->zb_objset, 351 DMU_USERUSED_OBJECT); 352 } 353 354 err = traverse_dnode(td, mdnp, zb->zb_objset, 355 DMU_META_DNODE_OBJECT); 356 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) { 357 err = traverse_dnode(td, gdnp, zb->zb_objset, 358 DMU_GROUPUSED_OBJECT); 359 } 360 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) { 361 err = traverse_dnode(td, udnp, zb->zb_objset, 362 DMU_USERUSED_OBJECT); 363 } 364 } 365 366 if (buf) 367 (void) arc_buf_remove_ref(buf, &buf); 368 369post: 370 if (err == 0 && (td->td_flags & TRAVERSE_POST)) 371 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg); 372 373 if (hard && (err == EIO || err == ECKSUM)) { 374 /* 375 * Ignore this disk error as requested by the HARD flag, 376 * and continue traversal. 377 */ 378 err = 0; 379 } 380 381 /* 382 * If we are stopping here, set td_resume. 383 */ 384 if (td->td_resume != NULL && err != 0 && !td->td_paused) { 385 td->td_resume->zb_objset = zb->zb_objset; 386 td->td_resume->zb_object = zb->zb_object; 387 td->td_resume->zb_level = 0; 388 /* 389 * If we have stopped on an indirect block (e.g. due to 390 * i/o error), we have not visited anything below it. 391 * Set the bookmark to the first level-0 block that we need 392 * to visit. This way, the resuming code does not need to 393 * deal with resuming from indirect blocks. 394 */ 395 td->td_resume->zb_blkid = zb->zb_blkid << 396 (zb->zb_level * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT)); 397 td->td_paused = B_TRUE; 398 } 399 400 return (err); 401} 402 403static void 404prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *dnp, 405 uint64_t objset, uint64_t object) 406{ 407 int j; 408 zbookmark_phys_t czb; 409 410 for (j = 0; j < dnp->dn_nblkptr; j++) { 411 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j); 412 traverse_prefetch_metadata(td, &dnp->dn_blkptr[j], &czb); 413 } 414 415 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { 416 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID); 417 traverse_prefetch_metadata(td, &dnp->dn_spill, &czb); 418 } 419} 420 421static int 422traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp, 423 uint64_t objset, uint64_t object) 424{ 425 int j, err = 0; 426 zbookmark_phys_t czb; 427 428 for (j = 0; j < dnp->dn_nblkptr; j++) { 429 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j); 430 err = traverse_visitbp(td, dnp, &dnp->dn_blkptr[j], &czb); 431 if (err != 0) 432 break; 433 } 434 435 if (err == 0 && dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) { 436 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID); 437 err = traverse_visitbp(td, dnp, &dnp->dn_spill, &czb); 438 } 439 return (err); 440} 441 442/* ARGSUSED */ 443static int 444traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp, 445 const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg) 446{ 447 prefetch_data_t *pfd = arg; 448 arc_flags_t aflags = ARC_FLAG_NOWAIT | ARC_FLAG_PREFETCH; 449 450 ASSERT(pfd->pd_blks_fetched >= 0); 451 if (pfd->pd_cancel) 452 return (SET_ERROR(EINTR)); 453 454 if (!prefetch_needed(pfd, bp)) 455 return (0); 456 457 mutex_enter(&pfd->pd_mtx); 458 while (!pfd->pd_cancel && pfd->pd_blks_fetched >= pfd->pd_blks_max) 459 cv_wait(&pfd->pd_cv, &pfd->pd_mtx); 460 pfd->pd_blks_fetched++; 461 cv_broadcast(&pfd->pd_cv); 462 mutex_exit(&pfd->pd_mtx); 463 464 (void) arc_read(NULL, spa, bp, NULL, NULL, ZIO_PRIORITY_ASYNC_READ, 465 ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, &aflags, zb); 466 467 return (0); 468} 469 470static void 471traverse_prefetch_thread(void *arg) 472{ 473 traverse_data_t *td_main = arg; 474 traverse_data_t td = *td_main; 475 zbookmark_phys_t czb; 476 477 td.td_func = traverse_prefetcher; 478 td.td_arg = td_main->td_pfd; 479 td.td_pfd = NULL; 480 481 SET_BOOKMARK(&czb, td.td_objset, 482 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID); 483 (void) traverse_visitbp(&td, NULL, td.td_rootbp, &czb); 484 485 mutex_enter(&td_main->td_pfd->pd_mtx); 486 td_main->td_pfd->pd_exited = B_TRUE; 487 cv_broadcast(&td_main->td_pfd->pd_cv); 488 mutex_exit(&td_main->td_pfd->pd_mtx); 489} 490 491/* 492 * NB: dataset must not be changing on-disk (eg, is a snapshot or we are 493 * in syncing context). 494 */ 495static int 496traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp, 497 uint64_t txg_start, zbookmark_phys_t *resume, int flags, 498 blkptr_cb_t func, void *arg) 499{ 500 traverse_data_t td; 501 prefetch_data_t pd = { 0 }; 502 zbookmark_phys_t czb; 503 int err; 504 505 ASSERT(ds == NULL || objset == ds->ds_object); 506 ASSERT(!(flags & TRAVERSE_PRE) || !(flags & TRAVERSE_POST)); 507 508 /* 509 * The data prefetching mechanism (the prefetch thread) is incompatible 510 * with resuming from a bookmark. 511 */ 512 ASSERT(resume == NULL || !(flags & TRAVERSE_PREFETCH_DATA)); 513 514 td.td_spa = spa; 515 td.td_objset = objset; 516 td.td_rootbp = rootbp; 517 td.td_min_txg = txg_start; 518 td.td_resume = resume; 519 td.td_func = func; 520 td.td_arg = arg; 521 td.td_pfd = &pd; 522 td.td_flags = flags; 523 td.td_paused = B_FALSE; 524 525 if (spa_feature_is_active(spa, SPA_FEATURE_HOLE_BIRTH)) { 526 VERIFY(spa_feature_enabled_txg(spa, 527 SPA_FEATURE_HOLE_BIRTH, &td.td_hole_birth_enabled_txg)); 528 } else { 529 td.td_hole_birth_enabled_txg = 0; 530 } 531 532 pd.pd_blks_max = zfs_pd_blks_max; 533 pd.pd_flags = flags; 534 mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL); 535 cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL); 536 537 /* See comment on ZIL traversal in dsl_scan_visitds. */ 538 if (ds != NULL && !dsl_dataset_is_snapshot(ds) && !BP_IS_HOLE(rootbp)) { 539 arc_flags_t flags = ARC_FLAG_WAIT; 540 objset_phys_t *osp; 541 arc_buf_t *buf; 542 543 err = arc_read(NULL, td.td_spa, rootbp, 544 arc_getbuf_func, &buf, 545 ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, NULL); 546 if (err != 0) 547 return (err); 548 549 osp = buf->b_data; 550 traverse_zil(&td, &osp->os_zil_header); 551 (void) arc_buf_remove_ref(buf, &buf); 552 } 553 554 if (!(flags & TRAVERSE_PREFETCH_DATA) || 555 0 == taskq_dispatch(system_taskq, traverse_prefetch_thread, 556 &td, TQ_NOQUEUE)) 557 pd.pd_exited = B_TRUE; 558 559 SET_BOOKMARK(&czb, td.td_objset, 560 ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID); 561 err = traverse_visitbp(&td, NULL, rootbp, &czb); 562 563 mutex_enter(&pd.pd_mtx); 564 pd.pd_cancel = B_TRUE; 565 cv_broadcast(&pd.pd_cv); 566 while (!pd.pd_exited) 567 cv_wait(&pd.pd_cv, &pd.pd_mtx); 568 mutex_exit(&pd.pd_mtx); 569 570 mutex_destroy(&pd.pd_mtx); 571 cv_destroy(&pd.pd_cv); 572 573 return (err); 574} 575 576/* 577 * NB: dataset must not be changing on-disk (eg, is a snapshot or we are 578 * in syncing context). 579 */ 580int 581traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start, int flags, 582 blkptr_cb_t func, void *arg) 583{ 584 return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds, ds->ds_object, 585 &dsl_dataset_phys(ds)->ds_bp, txg_start, NULL, flags, func, arg)); 586} 587 588int 589traverse_dataset_destroyed(spa_t *spa, blkptr_t *blkptr, 590 uint64_t txg_start, zbookmark_phys_t *resume, int flags, 591 blkptr_cb_t func, void *arg) 592{ 593 return (traverse_impl(spa, NULL, ZB_DESTROYED_OBJSET, 594 blkptr, txg_start, resume, flags, func, arg)); 595} 596 597/* 598 * NB: pool must not be changing on-disk (eg, from zdb or sync context). 599 */ 600int 601traverse_pool(spa_t *spa, uint64_t txg_start, int flags, 602 blkptr_cb_t func, void *arg) 603{ 604 int err; 605 uint64_t obj; 606 dsl_pool_t *dp = spa_get_dsl(spa); 607 objset_t *mos = dp->dp_meta_objset; 608 boolean_t hard = (flags & TRAVERSE_HARD); 609 610 /* visit the MOS */ 611 err = traverse_impl(spa, NULL, 0, spa_get_rootblkptr(spa), 612 txg_start, NULL, flags, func, arg); 613 if (err != 0) 614 return (err); 615 616 /* visit each dataset */ 617 for (obj = 1; err == 0; 618 err = dmu_object_next(mos, &obj, FALSE, txg_start)) { 619 dmu_object_info_t doi; 620 621 err = dmu_object_info(mos, obj, &doi); 622 if (err != 0) { 623 if (hard) 624 continue; 625 break; 626 } 627 628 if (doi.doi_bonus_type == DMU_OT_DSL_DATASET) { 629 dsl_dataset_t *ds; 630 uint64_t txg = txg_start; 631 632 dsl_pool_config_enter(dp, FTAG); 633 err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds); 634 dsl_pool_config_exit(dp, FTAG); 635 if (err != 0) { 636 if (hard) 637 continue; 638 break; 639 } 640 if (dsl_dataset_phys(ds)->ds_prev_snap_txg > txg) 641 txg = dsl_dataset_phys(ds)->ds_prev_snap_txg; 642 err = traverse_dataset(ds, txg, flags, func, arg); 643 dsl_dataset_rele(ds, FTAG); 644 if (err != 0) 645 break; 646 } 647 } 648 if (err == ESRCH) 649 err = 0; 650 return (err); 651} 652