sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dmu_traverse.c

   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         blkptr_cb_t *td_func;
  63         void *td_arg;
  64 } traverse_data_t;
  65
  66 static int traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,
  67     uint64_t objset, uint64_t object);
  68 static void prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *,
  69     uint64_t objset, uint64_t object);
  70
  71 static int
  72 traverse_zil_block(zilog_t *zilog, blkptr_t *bp, void *arg, uint64_t claim_txg)
  73 {
  74         traverse_data_t *td = arg;
  75         zbookmark_phys_t zb;
  76
  77         if (BP_IS_HOLE(bp))
  78                 return (0);
  79
  80         if (claim_txg == 0 && bp->blk_birth >= spa_first_txg(td->td_spa))
  81                 return (0);
  82
  83         SET_BOOKMARK(&zb, td->td_objset, ZB_ZIL_OBJECT, ZB_ZIL_LEVEL,
  84             bp->blk_cksum.zc_word[ZIL_ZC_SEQ]);
  85
  86         (void) td->td_func(td->td_spa, zilog, bp, &zb, NULL, td->td_arg);
  87
  88         return (0);
  89 }
  90
  91 static int
  92 traverse_zil_record(zilog_t *zilog, lr_t *lrc, void *arg, uint64_t claim_txg)
  93 {
  94         traverse_data_t *td = arg;
  95
  96         if (lrc->lrc_txtype == TX_WRITE) {
  97                 lr_write_t *lr = (lr_write_t *)lrc;
  98                 blkptr_t *bp = &lr->lr_blkptr;
  99                 zbookmark_phys_t zb;
 100
 101                 if (BP_IS_HOLE(bp))
 102                         return (0);
 103
 104                 if (claim_txg == 0 || bp->blk_birth < claim_txg)
 105                         return (0);
 106
 107                 SET_BOOKMARK(&zb, td->td_objset, lr->lr_foid,
 108                     ZB_ZIL_LEVEL, lr->lr_offset / BP_GET_LSIZE(bp));
 109
 110                 (void) td->td_func(td->td_spa, zilog, bp, &zb, NULL,
 111                     td->td_arg);
 112         }
 113         return (0);
 114 }
 115
 116 static void
 117 traverse_zil(traverse_data_t *td, zil_header_t *zh)
 118 {
 119         uint64_t claim_txg = zh->zh_claim_txg;
 120         zilog_t *zilog;
 121
 122         /*
 123          * We only want to visit blocks that have been claimed but not yet
 124          * replayed; plus, in read-only mode, blocks that are already stable.
 125          */
 126         if (claim_txg == 0 && spa_writeable(td->td_spa))
 127                 return;
 128
 129         zilog = zil_alloc(spa_get_dsl(td->td_spa)->dp_meta_objset, zh);
 130
 131         (void) zil_parse(zilog, traverse_zil_block, traverse_zil_record, td,
 132             claim_txg);
 133
 134         zil_free(zilog);
 135 }
 136
 137 typedef enum resume_skip {
 138         RESUME_SKIP_ALL,
 139         RESUME_SKIP_NONE,
 140         RESUME_SKIP_CHILDREN
 141 } resume_skip_t;
 142
 143 /*
 144  * Returns RESUME_SKIP_ALL if td indicates that we are resuming a traversal and
 145  * the block indicated by zb does not need to be visited at all. Returns
 146  * RESUME_SKIP_CHILDREN if we are resuming a post traversal and we reach the
 147  * resume point. This indicates that this block should be visited but not its
 148  * children (since they must have been visited in a previous traversal).
 149  * Otherwise returns RESUME_SKIP_NONE.
 150  */
 151 static resume_skip_t
 152 resume_skip_check(traverse_data_t *td, const dnode_phys_t *dnp,
 153     const zbookmark_phys_t *zb)
 154 {
 155         if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume)) {
 156                 /*
 157                  * If we already visited this bp & everything below,
 158                  * don't bother doing it again.
 159                  */
 160                 if (zbookmark_is_before(dnp, zb, td->td_resume))
 161                         return (RESUME_SKIP_ALL);
 162
 163                 /*
 164                  * If we found the block we're trying to resume from, zero
 165                  * the bookmark out to indicate that we have resumed.
 166                  */
 167                 if (bcmp(zb, td->td_resume, sizeof (*zb)) == 0) {
 168                         bzero(td->td_resume, sizeof (*zb));
 169                         if (td->td_flags & TRAVERSE_POST)
 170                                 return (RESUME_SKIP_CHILDREN);
 171                 }
 172         }
 173         return (RESUME_SKIP_NONE);
 174 }
 175
 176 static void
 177 traverse_prefetch_metadata(traverse_data_t *td,
 178     const blkptr_t *bp, const zbookmark_phys_t *zb)
 179 {
 180         uint32_t flags = ARC_NOWAIT | ARC_PREFETCH;
 181
 182         if (!(td->td_flags & TRAVERSE_PREFETCH_METADATA))
 183                 return;
 184         /*
 185          * If we are in the process of resuming, don't prefetch, because
 186          * some children will not be needed (and in fact may have already
 187          * been freed).
 188          */
 189         if (td->td_resume != NULL && !ZB_IS_ZERO(td->td_resume))
 190                 return;
 191         if (BP_IS_HOLE(bp) || bp->blk_birth <= td->td_min_txg)
 192                 return;
 193         if (BP_GET_LEVEL(bp) == 0 && BP_GET_TYPE(bp) != DMU_OT_DNODE)
 194                 return;
 195
 196         (void) arc_read(NULL, td->td_spa, bp, NULL, NULL,
 197             ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 198 }
 199
 200 static boolean_t
 201 prefetch_needed(prefetch_data_t *pfd, const blkptr_t *bp)
 202 {
 203         ASSERT(pfd->pd_flags & TRAVERSE_PREFETCH_DATA);
 204         if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp) ||
 205             BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG)
 206                 return (B_FALSE);
 207         return (B_TRUE);
 208 }
 209
 210 static int
 211 traverse_visitbp(traverse_data_t *td, const dnode_phys_t *dnp,
 212     const blkptr_t *bp, const zbookmark_phys_t *zb)
 213 {
 214         zbookmark_phys_t czb;
 215         int err = 0;
 216         arc_buf_t *buf = NULL;
 217         prefetch_data_t *pd = td->td_pfd;
 218         boolean_t hard = td->td_flags & TRAVERSE_HARD;
 219
 220         switch (resume_skip_check(td, dnp, zb)) {
 221         case RESUME_SKIP_ALL:
 222                 return (0);
 223         case RESUME_SKIP_CHILDREN:
 224                 goto post;
 225         case RESUME_SKIP_NONE:
 226                 break;
 227         default:
 228                 ASSERT(0);
 229         }
 230
 231         if (bp->blk_birth == 0) {
 232                 if (spa_feature_is_active(td->td_spa, SPA_FEATURE_HOLE_BIRTH)) {
 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                         uint64_t hole_birth_enabled_txg;
 246                         VERIFY(spa_feature_enabled_txg(td->td_spa,
 247                             SPA_FEATURE_HOLE_BIRTH, &hole_birth_enabled_txg));
 248                         if (hole_birth_enabled_txg < td->td_min_txg)
 249                                 return (0);
 250                 }
 251         } else if (bp->blk_birth <= td->td_min_txg) {
 252                 return (0);
 253         }
 254
 255         if (pd != NULL && !pd->pd_exited && prefetch_needed(pd, bp)) {
 256                 mutex_enter(&pd->pd_mtx);
 257                 ASSERT(pd->pd_blks_fetched >= 0);
 258                 while (pd->pd_blks_fetched == 0 && !pd->pd_exited)
 259                         cv_wait(&pd->pd_cv, &pd->pd_mtx);
 260                 pd->pd_blks_fetched--;
 261                 cv_broadcast(&pd->pd_cv);
 262                 mutex_exit(&pd->pd_mtx);
 263         }
 264
 265         if (BP_IS_HOLE(bp)) {
 266                 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
 267                 if (err != 0)
 268                         goto post;
 269                 return (0);
 270         }
 271
 272         if (td->td_flags & TRAVERSE_PRE) {
 273                 err = td->td_func(td->td_spa, NULL, bp, zb, dnp,
 274                     td->td_arg);
 275                 if (err == TRAVERSE_VISIT_NO_CHILDREN)
 276                         return (0);
 277                 if (err != 0)
 278                         goto post;
 279         }
 280
 281         if (BP_GET_LEVEL(bp) > 0) {
 282                 uint32_t flags = ARC_WAIT;
 283                 int i;
 284                 blkptr_t *cbp;
 285                 int epb = BP_GET_LSIZE(bp) >> SPA_BLKPTRSHIFT;
 286
 287                 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
 288                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 289                 if (err != 0)
 290                         goto post;
 291                 cbp = buf->b_data;
 292
 293                 for (i = 0; i < epb; i++) {
 294                         SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
 295                             zb->zb_level - 1,
 296                             zb->zb_blkid * epb + i);
 297                         traverse_prefetch_metadata(td, &cbp[i], &czb);
 298                 }
 299
 300                 /* recursively visitbp() blocks below this */
 301                 for (i = 0; i < epb; i++) {
 302                         SET_BOOKMARK(&czb, zb->zb_objset, zb->zb_object,
 303                             zb->zb_level - 1,
 304                             zb->zb_blkid * epb + i);
 305                         err = traverse_visitbp(td, dnp, &cbp[i], &czb);
 306                         if (err != 0)
 307                                 break;
 308                 }
 309         } else if (BP_GET_TYPE(bp) == DMU_OT_DNODE) {
 310                 uint32_t flags = ARC_WAIT;
 311                 int i;
 312                 int epb = BP_GET_LSIZE(bp) >> DNODE_SHIFT;
 313
 314                 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
 315                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 316                 if (err != 0)
 317                         goto post;
 318                 dnp = buf->b_data;
 319
 320                 for (i = 0; i < epb; i++) {
 321                         prefetch_dnode_metadata(td, &dnp[i], zb->zb_objset,
 322                             zb->zb_blkid * epb + i);
 323                 }
 324
 325                 /* recursively visitbp() blocks below this */
 326                 for (i = 0; i < epb; i++) {
 327                         err = traverse_dnode(td, &dnp[i], zb->zb_objset,
 328                             zb->zb_blkid * epb + i);
 329                         if (err != 0)
 330                                 break;
 331                 }
 332         } else if (BP_GET_TYPE(bp) == DMU_OT_OBJSET) {
 333                 uint32_t flags = ARC_WAIT;
 334                 objset_phys_t *osp;
 335                 dnode_phys_t *dnp;
 336
 337                 err = arc_read(NULL, td->td_spa, bp, arc_getbuf_func, &buf,
 338                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, zb);
 339                 if (err != 0)
 340                         goto post;
 341
 342                 osp = buf->b_data;
 343                 dnp = &osp->os_meta_dnode;
 344                 prefetch_dnode_metadata(td, dnp, zb->zb_objset,
 345                     DMU_META_DNODE_OBJECT);
 346                 if (arc_buf_size(buf) >= sizeof (objset_phys_t)) {
 347                         prefetch_dnode_metadata(td, &osp->os_groupused_dnode,
 348                             zb->zb_objset, DMU_GROUPUSED_OBJECT);
 349                         prefetch_dnode_metadata(td, &osp->os_userused_dnode,
 350                             zb->zb_objset, DMU_USERUSED_OBJECT);
 351                 }
 352
 353                 err = traverse_dnode(td, dnp, zb->zb_objset,
 354                     DMU_META_DNODE_OBJECT);
 355                 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
 356                         dnp = &osp->os_groupused_dnode;
 357                         err = traverse_dnode(td, dnp, zb->zb_objset,
 358                             DMU_GROUPUSED_OBJECT);
 359                 }
 360                 if (err == 0 && arc_buf_size(buf) >= sizeof (objset_phys_t)) {
 361                         dnp = &osp->os_userused_dnode;
 362                         err = traverse_dnode(td, dnp, zb->zb_objset,
 363                             DMU_USERUSED_OBJECT);
 364                 }
 365         }
 366
 367         if (buf)
 368                 (void) arc_buf_remove_ref(buf, &buf);
 369
 370 post:
 371         if (err == 0 && (td->td_flags & TRAVERSE_POST))
 372                 err = td->td_func(td->td_spa, NULL, bp, zb, dnp, td->td_arg);
 373
 374         if (hard && (err == EIO || err == ECKSUM)) {
 375                 /*
 376                  * Ignore this disk error as requested by the HARD flag,
 377                  * and continue traversal.
 378                  */
 379                 err = 0;
 380         }
 381
 382         /*
 383          * If we are stopping here, set td_resume.
 384          */
 385         if (td->td_resume != NULL && err != 0 && !td->td_paused) {
 386                 td->td_resume->zb_objset = zb->zb_objset;
 387                 td->td_resume->zb_object = zb->zb_object;
 388                 td->td_resume->zb_level = 0;
 389                 /*
 390                  * If we have stopped on an indirect block (e.g. due to
 391                  * i/o error), we have not visited anything below it.
 392                  * Set the bookmark to the first level-0 block that we need
 393                  * to visit.  This way, the resuming code does not need to
 394                  * deal with resuming from indirect blocks.
 395                  */
 396                 td->td_resume->zb_blkid = zb->zb_blkid <<
 397                     (zb->zb_level * (dnp->dn_indblkshift - SPA_BLKPTRSHIFT));
 398                 td->td_paused = B_TRUE;
 399         }
 400
 401         return (err);
 402 }
 403
 404 static void
 405 prefetch_dnode_metadata(traverse_data_t *td, const dnode_phys_t *dnp,
 406     uint64_t objset, uint64_t object)
 407 {
 408         int j;
 409         zbookmark_phys_t czb;
 410
 411         for (j = 0; j < dnp->dn_nblkptr; j++) {
 412                 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
 413                 traverse_prefetch_metadata(td, &dnp->dn_blkptr[j], &czb);
 414         }
 415
 416         if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
 417                 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
 418                 traverse_prefetch_metadata(td, &dnp->dn_spill, &czb);
 419         }
 420 }
 421
 422 static int
 423 traverse_dnode(traverse_data_t *td, const dnode_phys_t *dnp,
 424     uint64_t objset, uint64_t object)
 425 {
 426         int j, err = 0;
 427         zbookmark_phys_t czb;
 428
 429         for (j = 0; j < dnp->dn_nblkptr; j++) {
 430                 SET_BOOKMARK(&czb, objset, object, dnp->dn_nlevels - 1, j);
 431                 err = traverse_visitbp(td, dnp, &dnp->dn_blkptr[j], &czb);
 432                 if (err != 0)
 433                         break;
 434         }
 435
 436         if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
 437                 SET_BOOKMARK(&czb, objset, object, 0, DMU_SPILL_BLKID);
 438                 err = traverse_visitbp(td, dnp, &dnp->dn_spill, &czb);
 439         }
 440         return (err);
 441 }
 442
 443 /* ARGSUSED */
 444 static int
 445 traverse_prefetcher(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 446     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 447 {
 448         prefetch_data_t *pfd = arg;
 449         uint32_t aflags = ARC_NOWAIT | ARC_PREFETCH;
 450
 451         ASSERT(pfd->pd_blks_fetched >= 0);
 452         if (pfd->pd_cancel)
 453                 return (SET_ERROR(EINTR));
 454
 455         if (!prefetch_needed(pfd, bp))
 456                 return (0);
 457
 458         mutex_enter(&pfd->pd_mtx);
 459         while (!pfd->pd_cancel && pfd->pd_blks_fetched >= pfd->pd_blks_max)
 460                 cv_wait(&pfd->pd_cv, &pfd->pd_mtx);
 461         pfd->pd_blks_fetched++;
 462         cv_broadcast(&pfd->pd_cv);
 463         mutex_exit(&pfd->pd_mtx);
 464
 465         (void) arc_read(NULL, spa, bp, NULL, NULL, ZIO_PRIORITY_ASYNC_READ,
 466             ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE, &aflags, zb);
 467
 468         return (0);
 469 }
 470
 471 static void
 472 traverse_prefetch_thread(void *arg)
 473 {
 474         traverse_data_t *td_main = arg;
 475         traverse_data_t td = *td_main;
 476         zbookmark_phys_t czb;
 477
 478         td.td_func = traverse_prefetcher;
 479         td.td_arg = td_main->td_pfd;
 480         td.td_pfd = NULL;
 481
 482         SET_BOOKMARK(&czb, td.td_objset,
 483             ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
 484         (void) traverse_visitbp(&td, NULL, td.td_rootbp, &czb);
 485
 486         mutex_enter(&td_main->td_pfd->pd_mtx);
 487         td_main->td_pfd->pd_exited = B_TRUE;
 488         cv_broadcast(&td_main->td_pfd->pd_cv);
 489         mutex_exit(&td_main->td_pfd->pd_mtx);
 490 }
 491
 492 /*
 493  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
 494  * in syncing context).
 495  */
 496 static int
 497 traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
 498     uint64_t txg_start, zbookmark_phys_t *resume, int flags,
 499     blkptr_cb_t func, void *arg)
 500 {
 501         traverse_data_t td;
 502         prefetch_data_t pd = { 0 };
 503         zbookmark_phys_t czb;
 504         int err;
 505
 506         ASSERT(ds == NULL || objset == ds->ds_object);
 507         ASSERT(!(flags & TRAVERSE_PRE) || !(flags & TRAVERSE_POST));
 508
 509         /*
 510          * The data prefetching mechanism (the prefetch thread) is incompatible
 511          * with resuming from a bookmark.
 512          */
 513         ASSERT(resume == NULL || !(flags & TRAVERSE_PREFETCH_DATA));
 514
 515         td.td_spa = spa;
 516         td.td_objset = objset;
 517         td.td_rootbp = rootbp;
 518         td.td_min_txg = txg_start;
 519         td.td_resume = resume;
 520         td.td_func = func;
 521         td.td_arg = arg;
 522         td.td_pfd = &pd;
 523         td.td_flags = flags;
 524         td.td_paused = B_FALSE;
 525
 526         pd.pd_blks_max = zfs_pd_blks_max;
 527         pd.pd_flags = flags;
 528         mutex_init(&pd.pd_mtx, NULL, MUTEX_DEFAULT, NULL);
 529         cv_init(&pd.pd_cv, NULL, CV_DEFAULT, NULL);
 530
 531         /* See comment on ZIL traversal in dsl_scan_visitds. */
 532         if (ds != NULL && !dsl_dataset_is_snapshot(ds) && !BP_IS_HOLE(rootbp)) {
 533                 uint32_t flags = ARC_WAIT;
 534                 objset_phys_t *osp;
 535                 arc_buf_t *buf;
 536
 537                 err = arc_read(NULL, td.td_spa, rootbp,
 538                     arc_getbuf_func, &buf,
 539                     ZIO_PRIORITY_ASYNC_READ, ZIO_FLAG_CANFAIL, &flags, NULL);
 540                 if (err != 0)
 541                         return (err);
 542
 543                 osp = buf->b_data;
 544                 traverse_zil(&td, &osp->os_zil_header);
 545                 (void) arc_buf_remove_ref(buf, &buf);
 546         }
 547
 548         if (!(flags & TRAVERSE_PREFETCH_DATA) ||
 549             0 == taskq_dispatch(system_taskq, traverse_prefetch_thread,
 550             &td, TQ_NOQUEUE))
 551                 pd.pd_exited = B_TRUE;
 552
 553         SET_BOOKMARK(&czb, td.td_objset,
 554             ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
 555         err = traverse_visitbp(&td, NULL, rootbp, &czb);
 556
 557         mutex_enter(&pd.pd_mtx);
 558         pd.pd_cancel = B_TRUE;
 559         cv_broadcast(&pd.pd_cv);
 560         while (!pd.pd_exited)
 561                 cv_wait(&pd.pd_cv, &pd.pd_mtx);
 562         mutex_exit(&pd.pd_mtx);
 563
 564         mutex_destroy(&pd.pd_mtx);
 565         cv_destroy(&pd.pd_cv);
 566
 567         return (err);
 568 }
 569
 570 /*
 571  * NB: dataset must not be changing on-disk (eg, is a snapshot or we are
 572  * in syncing context).
 573  */
 574 int
 575 traverse_dataset(dsl_dataset_t *ds, uint64_t txg_start, int flags,
 576     blkptr_cb_t func, void *arg)
 577 {
 578         return (traverse_impl(ds->ds_dir->dd_pool->dp_spa, ds, ds->ds_object,
 579             &ds->ds_phys->ds_bp, txg_start, NULL, flags, func, arg));
 580 }
 581
 582 int
 583 traverse_dataset_destroyed(spa_t *spa, blkptr_t *blkptr,
 584     uint64_t txg_start, zbookmark_phys_t *resume, int flags,
 585     blkptr_cb_t func, void *arg)
 586 {
 587         return (traverse_impl(spa, NULL, ZB_DESTROYED_OBJSET,
 588             blkptr, txg_start, resume, flags, func, arg));
 589 }
 590
 591 /*
 592  * NB: pool must not be changing on-disk (eg, from zdb or sync context).
 593  */
 594 int
 595 traverse_pool(spa_t *spa, uint64_t txg_start, int flags,
 596     blkptr_cb_t func, void *arg)
 597 {
 598         int err;
 599         uint64_t obj;
 600         dsl_pool_t *dp = spa_get_dsl(spa);
 601         objset_t *mos = dp->dp_meta_objset;
 602         boolean_t hard = (flags & TRAVERSE_HARD);
 603
 604         /* visit the MOS */
 605         err = traverse_impl(spa, NULL, 0, spa_get_rootblkptr(spa),
 606             txg_start, NULL, flags, func, arg);
 607         if (err != 0)
 608                 return (err);
 609
 610         /* visit each dataset */
 611         for (obj = 1; err == 0;
 612             err = dmu_object_next(mos, &obj, FALSE, txg_start)) {
 613                 dmu_object_info_t doi;
 614
 615                 err = dmu_object_info(mos, obj, &doi);
 616                 if (err != 0) {
 617                         if (hard)
 618                                 continue;
 619                         break;
 620                 }
 621
 622                 if (doi.doi_bonus_type == DMU_OT_DSL_DATASET) {
 623                         dsl_dataset_t *ds;
 624                         uint64_t txg = txg_start;
 625
 626                         dsl_pool_config_enter(dp, FTAG);
 627                         err = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
 628                         dsl_pool_config_exit(dp, FTAG);
 629                         if (err != 0) {
 630                                 if (hard)
 631                                         continue;
 632                                 break;
 633                         }
 634                         if (ds->ds_phys->ds_prev_snap_txg > txg)
 635                                 txg = ds->ds_phys->ds_prev_snap_txg;
 636                         err = traverse_dataset(ds, txg, flags, func, arg);
 637                         dsl_dataset_rele(ds, FTAG);
 638                         if (err != 0)
 639                                 break;
 640                 }
 641         }
 642         if (err == ESRCH)
 643                 err = 0;
 644         return (err);
 645 }