granicus.if.org Git - zfs/blob - module/zfs/dsl_destroy.c

   1 /*
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   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, 2018 by Delphix. All rights reserved.
  24  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  25  * Copyright (c) 2013 by Joyent, Inc. All rights reserved.
  26  * Copyright (c) 2016 Actifio, Inc. All rights reserved.
  27  */
  28
  29 #include <sys/zfs_context.h>
  30 #include <sys/dsl_userhold.h>
  31 #include <sys/dsl_dataset.h>
  32 #include <sys/dsl_synctask.h>
  33 #include <sys/dsl_destroy.h>
  34 #include <sys/dmu_tx.h>
  35 #include <sys/dsl_pool.h>
  36 #include <sys/dsl_dir.h>
  37 #include <sys/dmu_traverse.h>
  38 #include <sys/dsl_scan.h>
  39 #include <sys/dmu_objset.h>
  40 #include <sys/zap.h>
  41 #include <sys/zfeature.h>
  42 #include <sys/zfs_ioctl.h>
  43 #include <sys/dsl_deleg.h>
  44 #include <sys/dmu_impl.h>
  45 #include <sys/zvol.h>
  46 #include <sys/zcp.h>
  47
  48 int
  49 dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
  50 {
  51         if (!ds->ds_is_snapshot)
  52                 return (SET_ERROR(EINVAL));
  53
  54         if (dsl_dataset_long_held(ds))
  55                 return (SET_ERROR(EBUSY));
  56
  57         /*
  58          * Only allow deferred destroy on pools that support it.
  59          * NOTE: deferred destroy is only supported on snapshots.
  60          */
  61         if (defer) {
  62                 if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
  63                     SPA_VERSION_USERREFS)
  64                         return (SET_ERROR(ENOTSUP));
  65                 return (0);
  66         }
  67
  68         /*
  69          * If this snapshot has an elevated user reference count,
  70          * we can't destroy it yet.
  71          */
  72         if (ds->ds_userrefs > 0)
  73                 return (SET_ERROR(EBUSY));
  74
  75         /*
  76          * Can't delete a branch point.
  77          */
  78         if (dsl_dataset_phys(ds)->ds_num_children > 1)
  79                 return (SET_ERROR(EEXIST));
  80
  81         return (0);
  82 }
  83
  84 int
  85 dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
  86 {
  87         dsl_destroy_snapshot_arg_t *ddsa = arg;
  88         const char *dsname = ddsa->ddsa_name;
  89         boolean_t defer = ddsa->ddsa_defer;
  90
  91         dsl_pool_t *dp = dmu_tx_pool(tx);
  92         int error = 0;
  93         dsl_dataset_t *ds;
  94
  95         error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
  96
  97         /*
  98          * If the snapshot does not exist, silently ignore it, and
  99          * dsl_destroy_snapshot_sync() will be a no-op
 100          * (it's "already destroyed").
 101          */
 102         if (error == ENOENT)
 103                 return (0);
 104
 105         if (error == 0) {
 106                 error = dsl_destroy_snapshot_check_impl(ds, defer);
 107                 dsl_dataset_rele(ds, FTAG);
 108         }
 109
 110         return (error);
 111 }
 112
 113 struct process_old_arg {
 114         dsl_dataset_t *ds;
 115         dsl_dataset_t *ds_prev;
 116         boolean_t after_branch_point;
 117         zio_t *pio;
 118         uint64_t used, comp, uncomp;
 119 };
 120
 121 static int
 122 process_old_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 123 {
 124         struct process_old_arg *poa = arg;
 125         dsl_pool_t *dp = poa->ds->ds_dir->dd_pool;
 126
 127         ASSERT(!BP_IS_HOLE(bp));
 128
 129         if (bp->blk_birth <= dsl_dataset_phys(poa->ds)->ds_prev_snap_txg) {
 130                 dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, tx);
 131                 if (poa->ds_prev && !poa->after_branch_point &&
 132                     bp->blk_birth >
 133                     dsl_dataset_phys(poa->ds_prev)->ds_prev_snap_txg) {
 134                         dsl_dataset_phys(poa->ds_prev)->ds_unique_bytes +=
 135                             bp_get_dsize_sync(dp->dp_spa, bp);
 136                 }
 137         } else {
 138                 poa->used += bp_get_dsize_sync(dp->dp_spa, bp);
 139                 poa->comp += BP_GET_PSIZE(bp);
 140                 poa->uncomp += BP_GET_UCSIZE(bp);
 141                 dsl_free_sync(poa->pio, dp, tx->tx_txg, bp);
 142         }
 143         return (0);
 144 }
 145
 146 static void
 147 process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev,
 148     dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx)
 149 {
 150         struct process_old_arg poa = { 0 };
 151         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 152         objset_t *mos = dp->dp_meta_objset;
 153         uint64_t deadlist_obj;
 154
 155         ASSERT(ds->ds_deadlist.dl_oldfmt);
 156         ASSERT(ds_next->ds_deadlist.dl_oldfmt);
 157
 158         poa.ds = ds;
 159         poa.ds_prev = ds_prev;
 160         poa.after_branch_point = after_branch_point;
 161         poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 162         VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
 163             process_old_cb, &poa, tx));
 164         VERIFY0(zio_wait(poa.pio));
 165         ASSERT3U(poa.used, ==, dsl_dataset_phys(ds)->ds_unique_bytes);
 166
 167         /* change snapused */
 168         dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 169             -poa.used, -poa.comp, -poa.uncomp, tx);
 170
 171         /* swap next's deadlist to our deadlist */
 172         dsl_deadlist_close(&ds->ds_deadlist);
 173         dsl_deadlist_close(&ds_next->ds_deadlist);
 174         deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
 175         dsl_dataset_phys(ds)->ds_deadlist_obj =
 176             dsl_dataset_phys(ds_next)->ds_deadlist_obj;
 177         dsl_dataset_phys(ds_next)->ds_deadlist_obj = deadlist_obj;
 178         dsl_deadlist_open(&ds->ds_deadlist, mos,
 179             dsl_dataset_phys(ds)->ds_deadlist_obj);
 180         dsl_deadlist_open(&ds_next->ds_deadlist, mos,
 181             dsl_dataset_phys(ds_next)->ds_deadlist_obj);
 182 }
 183
 184 struct removeclonesnode {
 185         list_node_t link;
 186         dsl_dataset_t *ds;
 187 };
 188
 189 static void
 190 dsl_dataset_remove_clones_key(dsl_dataset_t *ds, uint64_t mintxg, dmu_tx_t *tx)
 191 {
 192         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 193         list_t clones;
 194         struct removeclonesnode *rcn;
 195
 196         list_create(&clones, sizeof (struct removeclonesnode),
 197             offsetof(struct removeclonesnode, link));
 198
 199         rcn = kmem_zalloc(sizeof (struct removeclonesnode), KM_SLEEP);
 200         rcn->ds = ds;
 201         list_insert_head(&clones, rcn);
 202
 203         for (; rcn != NULL; rcn = list_next(&clones, rcn)) {
 204                 zap_cursor_t zc;
 205                 zap_attribute_t za;
 206                 /*
 207                  * If it is the old version, dd_clones doesn't exist so we can't
 208                  * find the clones, but dsl_deadlist_remove_key() is a no-op so
 209                  * it doesn't matter.
 210                  */
 211                 if (dsl_dir_phys(rcn->ds->ds_dir)->dd_clones == 0)
 212                         continue;
 213
 214                 for (zap_cursor_init(&zc, mos,
 215                     dsl_dir_phys(rcn->ds->ds_dir)->dd_clones);
 216                     zap_cursor_retrieve(&zc, &za) == 0;
 217                     zap_cursor_advance(&zc)) {
 218                         dsl_dataset_t *clone;
 219
 220                         VERIFY0(dsl_dataset_hold_obj(rcn->ds->ds_dir->dd_pool,
 221                             za.za_first_integer, FTAG, &clone));
 222                         if (clone->ds_dir->dd_origin_txg > mintxg) {
 223                                 dsl_deadlist_remove_key(&clone->ds_deadlist,
 224                                     mintxg, tx);
 225                                 if (dsl_dataset_remap_deadlist_exists(clone)) {
 226                                         dsl_deadlist_remove_key(
 227                                             &clone->ds_remap_deadlist, mintxg,
 228                                             tx);
 229                                 }
 230                                 rcn = kmem_zalloc(
 231                                     sizeof (struct removeclonesnode), KM_SLEEP);
 232                                 rcn->ds = clone;
 233                                 list_insert_tail(&clones, rcn);
 234                         } else {
 235                                 dsl_dataset_rele(clone, FTAG);
 236                         }
 237                 }
 238                 zap_cursor_fini(&zc);
 239         }
 240
 241         rcn = list_remove_head(&clones);
 242         kmem_free(rcn, sizeof (struct removeclonesnode));
 243         while ((rcn = list_remove_head(&clones)) != NULL) {
 244                 dsl_dataset_rele(rcn->ds, FTAG);
 245                 kmem_free(rcn, sizeof (struct removeclonesnode));
 246         }
 247         list_destroy(&clones);
 248 }
 249
 250 static void
 251 dsl_destroy_snapshot_handle_remaps(dsl_dataset_t *ds, dsl_dataset_t *ds_next,
 252     dmu_tx_t *tx)
 253 {
 254         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 255
 256         /* Move blocks to be obsoleted to pool's obsolete list. */
 257         if (dsl_dataset_remap_deadlist_exists(ds_next)) {
 258                 if (!bpobj_is_open(&dp->dp_obsolete_bpobj))
 259                         dsl_pool_create_obsolete_bpobj(dp, tx);
 260
 261                 dsl_deadlist_move_bpobj(&ds_next->ds_remap_deadlist,
 262                     &dp->dp_obsolete_bpobj,
 263                     dsl_dataset_phys(ds)->ds_prev_snap_txg, tx);
 264         }
 265
 266         /* Merge our deadlist into next's and free it. */
 267         if (dsl_dataset_remap_deadlist_exists(ds)) {
 268                 uint64_t remap_deadlist_object =
 269                     dsl_dataset_get_remap_deadlist_object(ds);
 270                 ASSERT(remap_deadlist_object != 0);
 271
 272                 mutex_enter(&ds_next->ds_remap_deadlist_lock);
 273                 if (!dsl_dataset_remap_deadlist_exists(ds_next))
 274                         dsl_dataset_create_remap_deadlist(ds_next, tx);
 275                 mutex_exit(&ds_next->ds_remap_deadlist_lock);
 276
 277                 dsl_deadlist_merge(&ds_next->ds_remap_deadlist,
 278                     remap_deadlist_object, tx);
 279                 dsl_dataset_destroy_remap_deadlist(ds, tx);
 280         }
 281 }
 282
 283 void
 284 dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 285 {
 286         int after_branch_point = FALSE;
 287         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 288         objset_t *mos = dp->dp_meta_objset;
 289         dsl_dataset_t *ds_prev = NULL;
 290         uint64_t obj;
 291
 292         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 293         rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
 294         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
 295         rrw_exit(&ds->ds_bp_rwlock, FTAG);
 296         ASSERT(zfs_refcount_is_zero(&ds->ds_longholds));
 297
 298         if (defer &&
 299             (ds->ds_userrefs > 0 ||
 300             dsl_dataset_phys(ds)->ds_num_children > 1)) {
 301                 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
 302                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 303                 dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_DEFER_DESTROY;
 304                 spa_history_log_internal_ds(ds, "defer_destroy", tx, "");
 305                 return;
 306         }
 307
 308         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
 309
 310         /* We need to log before removing it from the namespace. */
 311         spa_history_log_internal_ds(ds, "destroy", tx, "");
 312
 313         dsl_scan_ds_destroyed(ds, tx);
 314
 315         obj = ds->ds_object;
 316
 317         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
 318                 if (dsl_dataset_feature_is_active(ds, f))
 319                         dsl_dataset_deactivate_feature(ds, f, tx);
 320         }
 321         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 322                 ASSERT3P(ds->ds_prev, ==, NULL);
 323                 VERIFY0(dsl_dataset_hold_obj(dp,
 324                     dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &ds_prev));
 325                 after_branch_point =
 326                     (dsl_dataset_phys(ds_prev)->ds_next_snap_obj != obj);
 327
 328                 dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 329                 if (after_branch_point &&
 330                     dsl_dataset_phys(ds_prev)->ds_next_clones_obj != 0) {
 331                         dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
 332                         if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
 333                                 VERIFY0(zap_add_int(mos,
 334                                     dsl_dataset_phys(ds_prev)->
 335                                     ds_next_clones_obj,
 336                                     dsl_dataset_phys(ds)->ds_next_snap_obj,
 337                                     tx));
 338                         }
 339                 }
 340                 if (!after_branch_point) {
 341                         dsl_dataset_phys(ds_prev)->ds_next_snap_obj =
 342                             dsl_dataset_phys(ds)->ds_next_snap_obj;
 343                 }
 344         }
 345
 346         dsl_dataset_t *ds_next;
 347         uint64_t old_unique;
 348         uint64_t used = 0, comp = 0, uncomp = 0;
 349
 350         VERIFY0(dsl_dataset_hold_obj(dp,
 351             dsl_dataset_phys(ds)->ds_next_snap_obj, FTAG, &ds_next));
 352         ASSERT3U(dsl_dataset_phys(ds_next)->ds_prev_snap_obj, ==, obj);
 353
 354         old_unique = dsl_dataset_phys(ds_next)->ds_unique_bytes;
 355
 356         dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 357         dsl_dataset_phys(ds_next)->ds_prev_snap_obj =
 358             dsl_dataset_phys(ds)->ds_prev_snap_obj;
 359         dsl_dataset_phys(ds_next)->ds_prev_snap_txg =
 360             dsl_dataset_phys(ds)->ds_prev_snap_txg;
 361         ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
 362             ds_prev ? dsl_dataset_phys(ds_prev)->ds_creation_txg : 0);
 363
 364         if (ds_next->ds_deadlist.dl_oldfmt) {
 365                 process_old_deadlist(ds, ds_prev, ds_next,
 366                     after_branch_point, tx);
 367         } else {
 368                 /* Adjust prev's unique space. */
 369                 if (ds_prev && !after_branch_point) {
 370                         dsl_deadlist_space_range(&ds_next->ds_deadlist,
 371                             dsl_dataset_phys(ds_prev)->ds_prev_snap_txg,
 372                             dsl_dataset_phys(ds)->ds_prev_snap_txg,
 373                             &used, &comp, &uncomp);
 374                         dsl_dataset_phys(ds_prev)->ds_unique_bytes += used;
 375                 }
 376
 377                 /* Adjust snapused. */
 378                 dsl_deadlist_space_range(&ds_next->ds_deadlist,
 379                     dsl_dataset_phys(ds)->ds_prev_snap_txg, UINT64_MAX,
 380                     &used, &comp, &uncomp);
 381                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 382                     -used, -comp, -uncomp, tx);
 383
 384                 /* Move blocks to be freed to pool's free list. */
 385                 dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
 386                     &dp->dp_free_bpobj, dsl_dataset_phys(ds)->ds_prev_snap_txg,
 387                     tx);
 388                 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
 389                     DD_USED_HEAD, used, comp, uncomp, tx);
 390
 391                 /* Merge our deadlist into next's and free it. */
 392                 dsl_deadlist_merge(&ds_next->ds_deadlist,
 393                     dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 394         }
 395
 396         dsl_deadlist_close(&ds->ds_deadlist);
 397         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 398         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 399         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 400
 401         dsl_destroy_snapshot_handle_remaps(ds, ds_next, tx);
 402
 403         /* Collapse range in clone heads */
 404         dsl_dataset_remove_clones_key(ds,
 405             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 406
 407         if (ds_next->ds_is_snapshot) {
 408                 dsl_dataset_t *ds_nextnext;
 409
 410                 /*
 411                  * Update next's unique to include blocks which
 412                  * were previously shared by only this snapshot
 413                  * and it.  Those blocks will be born after the
 414                  * prev snap and before this snap, and will have
 415                  * died after the next snap and before the one
 416                  * after that (ie. be on the snap after next's
 417                  * deadlist).
 418                  */
 419                 VERIFY0(dsl_dataset_hold_obj(dp,
 420                     dsl_dataset_phys(ds_next)->ds_next_snap_obj,
 421                     FTAG, &ds_nextnext));
 422                 dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
 423                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 424                     dsl_dataset_phys(ds)->ds_creation_txg,
 425                     &used, &comp, &uncomp);
 426                 dsl_dataset_phys(ds_next)->ds_unique_bytes += used;
 427                 dsl_dataset_rele(ds_nextnext, FTAG);
 428                 ASSERT3P(ds_next->ds_prev, ==, NULL);
 429
 430                 /* Collapse range in this head. */
 431                 dsl_dataset_t *hds;
 432                 VERIFY0(dsl_dataset_hold_obj(dp,
 433                     dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &hds));
 434                 dsl_deadlist_remove_key(&hds->ds_deadlist,
 435                     dsl_dataset_phys(ds)->ds_creation_txg, tx);
 436                 if (dsl_dataset_remap_deadlist_exists(hds)) {
 437                         dsl_deadlist_remove_key(&hds->ds_remap_deadlist,
 438                             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 439                 }
 440                 dsl_dataset_rele(hds, FTAG);
 441
 442         } else {
 443                 ASSERT3P(ds_next->ds_prev, ==, ds);
 444                 dsl_dataset_rele(ds_next->ds_prev, ds_next);
 445                 ds_next->ds_prev = NULL;
 446                 if (ds_prev) {
 447                         VERIFY0(dsl_dataset_hold_obj(dp,
 448                             dsl_dataset_phys(ds)->ds_prev_snap_obj,
 449                             ds_next, &ds_next->ds_prev));
 450                 }
 451
 452                 dsl_dataset_recalc_head_uniq(ds_next);
 453
 454                 /*
 455                  * Reduce the amount of our unconsumed refreservation
 456                  * being charged to our parent by the amount of
 457                  * new unique data we have gained.
 458                  */
 459                 if (old_unique < ds_next->ds_reserved) {
 460                         int64_t mrsdelta;
 461                         uint64_t new_unique =
 462                             dsl_dataset_phys(ds_next)->ds_unique_bytes;
 463
 464                         ASSERT(old_unique <= new_unique);
 465                         mrsdelta = MIN(new_unique - old_unique,
 466                             ds_next->ds_reserved - old_unique);
 467                         dsl_dir_diduse_space(ds->ds_dir,
 468                             DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
 469                 }
 470         }
 471         dsl_dataset_rele(ds_next, FTAG);
 472
 473         /*
 474          * This must be done after the dsl_traverse(), because it will
 475          * re-open the objset.
 476          */
 477         if (ds->ds_objset) {
 478                 dmu_objset_evict(ds->ds_objset);
 479                 ds->ds_objset = NULL;
 480         }
 481
 482         /* remove from snapshot namespace */
 483         dsl_dataset_t *ds_head;
 484         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0);
 485         VERIFY0(dsl_dataset_hold_obj(dp,
 486             dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &ds_head));
 487         VERIFY0(dsl_dataset_get_snapname(ds));
 488 #ifdef ZFS_DEBUG
 489         {
 490                 uint64_t val;
 491                 int err;
 492
 493                 err = dsl_dataset_snap_lookup(ds_head,
 494                     ds->ds_snapname, &val);
 495                 ASSERT0(err);
 496                 ASSERT3U(val, ==, obj);
 497         }
 498 #endif
 499         VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx, B_TRUE));
 500         dsl_dataset_rele(ds_head, FTAG);
 501
 502         if (ds_prev != NULL)
 503                 dsl_dataset_rele(ds_prev, FTAG);
 504
 505         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 506
 507         if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
 508                 ASSERTV(uint64_t count);
 509                 ASSERT0(zap_count(mos,
 510                     dsl_dataset_phys(ds)->ds_next_clones_obj, &count) &&
 511                     count == 0);
 512                 VERIFY0(dmu_object_free(mos,
 513                     dsl_dataset_phys(ds)->ds_next_clones_obj, tx));
 514         }
 515         if (dsl_dataset_phys(ds)->ds_props_obj != 0)
 516                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_props_obj,
 517                     tx));
 518         if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0)
 519                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
 520                     tx));
 521         dsl_dir_rele(ds->ds_dir, ds);
 522         ds->ds_dir = NULL;
 523         dmu_object_free_zapified(mos, obj, tx);
 524 }
 525
 526 void
 527 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
 528 {
 529         dsl_destroy_snapshot_arg_t *ddsa = arg;
 530         const char *dsname = ddsa->ddsa_name;
 531         boolean_t defer = ddsa->ddsa_defer;
 532
 533         dsl_pool_t *dp = dmu_tx_pool(tx);
 534         dsl_dataset_t *ds;
 535
 536         int error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
 537         if (error == ENOENT)
 538                 return;
 539         ASSERT0(error);
 540         dsl_destroy_snapshot_sync_impl(ds, defer, tx);
 541         zvol_remove_minors(dp->dp_spa, dsname, B_TRUE);
 542         dsl_dataset_rele(ds, FTAG);
 543 }
 544
 545 /*
 546  * The semantics of this function are described in the comment above
 547  * lzc_destroy_snaps().  To summarize:
 548  *
 549  * The snapshots must all be in the same pool.
 550  *
 551  * Snapshots that don't exist will be silently ignored (considered to be
 552  * "already deleted").
 553  *
 554  * On success, all snaps will be destroyed and this will return 0.
 555  * On failure, no snaps will be destroyed, the errlist will be filled in,
 556  * and this will return an errno.
 557  */
 558 int
 559 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
 560     nvlist_t *errlist)
 561 {
 562         if (nvlist_next_nvpair(snaps, NULL) == NULL)
 563                 return (0);
 564
 565         /*
 566          * lzc_destroy_snaps() is documented to take an nvlist whose
 567          * values "don't matter".  We need to convert that nvlist to
 568          * one that we know can be converted to LUA. We also don't
 569          * care about any duplicate entries because the nvlist will
 570          * be converted to a LUA table which should take care of this.
 571          */
 572         nvlist_t *snaps_normalized;
 573         VERIFY0(nvlist_alloc(&snaps_normalized, 0, KM_SLEEP));
 574         for (nvpair_t *pair = nvlist_next_nvpair(snaps, NULL);
 575             pair != NULL; pair = nvlist_next_nvpair(snaps, pair)) {
 576                 fnvlist_add_boolean_value(snaps_normalized,
 577                     nvpair_name(pair), B_TRUE);
 578         }
 579
 580         nvlist_t *arg;
 581         VERIFY0(nvlist_alloc(&arg, 0, KM_SLEEP));
 582         fnvlist_add_nvlist(arg, "snaps", snaps_normalized);
 583         fnvlist_free(snaps_normalized);
 584         fnvlist_add_boolean_value(arg, "defer", defer);
 585
 586         nvlist_t *wrapper;
 587         VERIFY0(nvlist_alloc(&wrapper, 0, KM_SLEEP));
 588         fnvlist_add_nvlist(wrapper, ZCP_ARG_ARGLIST, arg);
 589         fnvlist_free(arg);
 590
 591         const char *program =
 592             "arg = ...\n"
 593             "snaps = arg['snaps']\n"
 594             "defer = arg['defer']\n"
 595             "errors = { }\n"
 596             "has_errors = false\n"
 597             "for snap, v in pairs(snaps) do\n"
 598             "    errno = zfs.check.destroy{snap, defer=defer}\n"
 599             "    zfs.debug('snap: ' .. snap .. ' errno: ' .. errno)\n"
 600             "    if errno == ENOENT then\n"
 601             "        snaps[snap] = nil\n"
 602             "    elseif errno ~= 0 then\n"
 603             "        errors[snap] = errno\n"
 604             "        has_errors = true\n"
 605             "    end\n"
 606             "end\n"
 607             "if has_errors then\n"
 608             "    return errors\n"
 609             "end\n"
 610             "for snap, v in pairs(snaps) do\n"
 611             "    errno = zfs.sync.destroy{snap, defer=defer}\n"
 612             "    assert(errno == 0)\n"
 613             "end\n"
 614             "return { }\n";
 615
 616         nvlist_t *result = fnvlist_alloc();
 617         int error = zcp_eval(nvpair_name(nvlist_next_nvpair(snaps, NULL)),
 618             program,
 619             B_TRUE,
 620             0,
 621             zfs_lua_max_memlimit,
 622             nvlist_next_nvpair(wrapper, NULL), result);
 623         if (error != 0) {
 624                 char *errorstr = NULL;
 625                 (void) nvlist_lookup_string(result, ZCP_RET_ERROR, &errorstr);
 626                 if (errorstr != NULL) {
 627                         zfs_dbgmsg(errorstr);
 628                 }
 629                 return (error);
 630         }
 631         fnvlist_free(wrapper);
 632
 633         /*
 634          * lzc_destroy_snaps() is documented to fill the errlist with
 635          * int32 values, so we need to covert the int64 values that are
 636          * returned from LUA.
 637          */
 638         int rv = 0;
 639         nvlist_t *errlist_raw = fnvlist_lookup_nvlist(result, ZCP_RET_RETURN);
 640         for (nvpair_t *pair = nvlist_next_nvpair(errlist_raw, NULL);
 641             pair != NULL; pair = nvlist_next_nvpair(errlist_raw, pair)) {
 642                 int32_t val = (int32_t)fnvpair_value_int64(pair);
 643                 if (rv == 0)
 644                         rv = val;
 645                 fnvlist_add_int32(errlist, nvpair_name(pair), val);
 646         }
 647         fnvlist_free(result);
 648         return (rv);
 649 }
 650
 651 int
 652 dsl_destroy_snapshot(const char *name, boolean_t defer)
 653 {
 654         int error;
 655         nvlist_t *nvl = fnvlist_alloc();
 656         nvlist_t *errlist = fnvlist_alloc();
 657
 658         fnvlist_add_boolean(nvl, name);
 659         error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
 660         fnvlist_free(errlist);
 661         fnvlist_free(nvl);
 662         return (error);
 663 }
 664
 665 struct killarg {
 666         dsl_dataset_t *ds;
 667         dmu_tx_t *tx;
 668 };
 669
 670 /* ARGSUSED */
 671 static int
 672 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 673     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 674 {
 675         struct killarg *ka = arg;
 676         dmu_tx_t *tx = ka->tx;
 677
 678         if (bp == NULL || BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
 679                 return (0);
 680
 681         if (zb->zb_level == ZB_ZIL_LEVEL) {
 682                 ASSERT(zilog != NULL);
 683                 /*
 684                  * It's a block in the intent log.  It has no
 685                  * accounting, so just free it.
 686                  */
 687                 dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
 688         } else {
 689                 ASSERT(zilog == NULL);
 690                 ASSERT3U(bp->blk_birth, >,
 691                     dsl_dataset_phys(ka->ds)->ds_prev_snap_txg);
 692                 (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
 693         }
 694
 695         return (0);
 696 }
 697
 698 static void
 699 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 700 {
 701         struct killarg ka;
 702
 703         /*
 704          * Free everything that we point to (that's born after
 705          * the previous snapshot, if we are a clone)
 706          *
 707          * NB: this should be very quick, because we already
 708          * freed all the objects in open context.
 709          */
 710         ka.ds = ds;
 711         ka.tx = tx;
 712         VERIFY0(traverse_dataset(ds,
 713             dsl_dataset_phys(ds)->ds_prev_snap_txg, TRAVERSE_POST |
 714             TRAVERSE_NO_DECRYPT, kill_blkptr, &ka));
 715         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 716             dsl_dataset_phys(ds)->ds_unique_bytes == 0);
 717 }
 718
 719 int
 720 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
 721 {
 722         int error;
 723         uint64_t count;
 724         objset_t *mos;
 725
 726         ASSERT(!ds->ds_is_snapshot);
 727         if (ds->ds_is_snapshot)
 728                 return (SET_ERROR(EINVAL));
 729
 730         if (zfs_refcount_count(&ds->ds_longholds) != expected_holds)
 731                 return (SET_ERROR(EBUSY));
 732
 733         mos = ds->ds_dir->dd_pool->dp_meta_objset;
 734
 735         /*
 736          * Can't delete a head dataset if there are snapshots of it.
 737          * (Except if the only snapshots are from the branch we cloned
 738          * from.)
 739          */
 740         if (ds->ds_prev != NULL &&
 741             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj == ds->ds_object)
 742                 return (SET_ERROR(EBUSY));
 743
 744         /*
 745          * Can't delete if there are children of this fs.
 746          */
 747         error = zap_count(mos,
 748             dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, &count);
 749         if (error != 0)
 750                 return (error);
 751         if (count != 0)
 752                 return (SET_ERROR(EEXIST));
 753
 754         if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 755             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 756             ds->ds_prev->ds_userrefs == 0) {
 757                 /* We need to remove the origin snapshot as well. */
 758                 if (!zfs_refcount_is_zero(&ds->ds_prev->ds_longholds))
 759                         return (SET_ERROR(EBUSY));
 760         }
 761         return (0);
 762 }
 763
 764 int
 765 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
 766 {
 767         dsl_destroy_head_arg_t *ddha = arg;
 768         dsl_pool_t *dp = dmu_tx_pool(tx);
 769         dsl_dataset_t *ds;
 770         int error;
 771
 772         error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
 773         if (error != 0)
 774                 return (error);
 775
 776         error = dsl_destroy_head_check_impl(ds, 0);
 777         dsl_dataset_rele(ds, FTAG);
 778         return (error);
 779 }
 780
 781 static void
 782 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
 783 {
 784         dsl_dir_t *dd;
 785         dsl_pool_t *dp = dmu_tx_pool(tx);
 786         objset_t *mos = dp->dp_meta_objset;
 787         dd_used_t t;
 788
 789         ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
 790
 791         VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
 792
 793         ASSERT0(dsl_dir_phys(dd)->dd_head_dataset_obj);
 794
 795         /*
 796          * Decrement the filesystem count for all parent filesystems.
 797          *
 798          * When we receive an incremental stream into a filesystem that already
 799          * exists, a temporary clone is created.  We never count this temporary
 800          * clone, whose name begins with a '%'.
 801          */
 802         if (dd->dd_myname[0] != '%' && dd->dd_parent != NULL)
 803                 dsl_fs_ss_count_adjust(dd->dd_parent, -1,
 804                     DD_FIELD_FILESYSTEM_COUNT, tx);
 805
 806         /*
 807          * Remove our reservation. The impl() routine avoids setting the
 808          * actual property, which would require the (already destroyed) ds.
 809          */
 810         dsl_dir_set_reservation_sync_impl(dd, 0, tx);
 811
 812         ASSERT0(dsl_dir_phys(dd)->dd_used_bytes);
 813         ASSERT0(dsl_dir_phys(dd)->dd_reserved);
 814         for (t = 0; t < DD_USED_NUM; t++)
 815                 ASSERT0(dsl_dir_phys(dd)->dd_used_breakdown[t]);
 816
 817         if (dd->dd_crypto_obj != 0) {
 818                 dsl_crypto_key_destroy_sync(dd->dd_crypto_obj, tx);
 819                 (void) spa_keystore_unload_wkey_impl(dp->dp_spa, dd->dd_object);
 820         }
 821
 822         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_child_dir_zapobj, tx));
 823         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_props_zapobj, tx));
 824         if (dsl_dir_phys(dd)->dd_clones != 0)
 825                 VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_clones, tx));
 826         VERIFY0(dsl_deleg_destroy(mos, dsl_dir_phys(dd)->dd_deleg_zapobj, tx));
 827         VERIFY0(zap_remove(mos,
 828             dsl_dir_phys(dd->dd_parent)->dd_child_dir_zapobj,
 829             dd->dd_myname, tx));
 830
 831         dsl_dir_rele(dd, FTAG);
 832         dmu_object_free_zapified(mos, ddobj, tx);
 833 }
 834
 835 void
 836 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
 837 {
 838         dsl_pool_t *dp = dmu_tx_pool(tx);
 839         objset_t *mos = dp->dp_meta_objset;
 840         uint64_t obj, ddobj, prevobj = 0;
 841         boolean_t rmorigin;
 842
 843         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
 844         ASSERT(ds->ds_prev == NULL ||
 845             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj != ds->ds_object);
 846         rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
 847         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
 848         rrw_exit(&ds->ds_bp_rwlock, FTAG);
 849         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 850
 851         /* We need to log before removing it from the namespace. */
 852         spa_history_log_internal_ds(ds, "destroy", tx, "");
 853
 854         rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
 855             DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 856             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 857             ds->ds_prev->ds_userrefs == 0);
 858
 859         /* Remove our reservation. */
 860         if (ds->ds_reserved != 0) {
 861                 dsl_dataset_set_refreservation_sync_impl(ds,
 862                     (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
 863                     0, tx);
 864                 ASSERT0(ds->ds_reserved);
 865         }
 866
 867         obj = ds->ds_object;
 868
 869         for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
 870                 if (dsl_dataset_feature_is_active(ds, f))
 871                         dsl_dataset_deactivate_feature(ds, f, tx);
 872         }
 873
 874         dsl_scan_ds_destroyed(ds, tx);
 875
 876         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 877                 /* This is a clone */
 878                 ASSERT(ds->ds_prev != NULL);
 879                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj, !=,
 880                     obj);
 881                 ASSERT0(dsl_dataset_phys(ds)->ds_next_snap_obj);
 882
 883                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 884                 if (dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj != 0) {
 885                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
 886                             obj, tx);
 887                 }
 888
 889                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_num_children, >, 1);
 890                 dsl_dataset_phys(ds->ds_prev)->ds_num_children--;
 891         }
 892
 893         /*
 894          * Destroy the deadlist.  Unless it's a clone, the
 895          * deadlist should be empty since the dataset has no snapshots.
 896          * (If it's a clone, it's safe to ignore the deadlist contents
 897          * since they are still referenced by the origin snapshot.)
 898          */
 899         dsl_deadlist_close(&ds->ds_deadlist);
 900         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 901         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 902         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 903
 904         if (dsl_dataset_remap_deadlist_exists(ds))
 905                 dsl_dataset_destroy_remap_deadlist(ds, tx);
 906
 907         objset_t *os;
 908         VERIFY0(dmu_objset_from_ds(ds, &os));
 909
 910         if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
 911                 old_synchronous_dataset_destroy(ds, tx);
 912         } else {
 913                 /*
 914                  * Move the bptree into the pool's list of trees to
 915                  * clean up and update space accounting information.
 916                  */
 917                 uint64_t used, comp, uncomp;
 918
 919                 zil_destroy_sync(dmu_objset_zil(os), tx);
 920
 921                 if (!spa_feature_is_active(dp->dp_spa,
 922                     SPA_FEATURE_ASYNC_DESTROY)) {
 923                         dsl_scan_t *scn = dp->dp_scan;
 924                         spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
 925                             tx);
 926                         dp->dp_bptree_obj = bptree_alloc(mos, tx);
 927                         VERIFY0(zap_add(mos,
 928                             DMU_POOL_DIRECTORY_OBJECT,
 929                             DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
 930                             &dp->dp_bptree_obj, tx));
 931                         ASSERT(!scn->scn_async_destroying);
 932                         scn->scn_async_destroying = B_TRUE;
 933                 }
 934
 935                 used = dsl_dir_phys(ds->ds_dir)->dd_used_bytes;
 936                 comp = dsl_dir_phys(ds->ds_dir)->dd_compressed_bytes;
 937                 uncomp = dsl_dir_phys(ds->ds_dir)->dd_uncompressed_bytes;
 938
 939                 ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 940                     dsl_dataset_phys(ds)->ds_unique_bytes == used);
 941
 942                 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
 943                 bptree_add(mos, dp->dp_bptree_obj,
 944                     &dsl_dataset_phys(ds)->ds_bp,
 945                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 946                     used, comp, uncomp, tx);
 947                 rrw_exit(&ds->ds_bp_rwlock, FTAG);
 948                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 949                     -used, -comp, -uncomp, tx);
 950                 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
 951                     used, comp, uncomp, tx);
 952         }
 953
 954         if (ds->ds_prev != NULL) {
 955                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 956                         VERIFY0(zap_remove_int(mos,
 957                             dsl_dir_phys(ds->ds_prev->ds_dir)->dd_clones,
 958                             ds->ds_object, tx));
 959                 }
 960                 prevobj = ds->ds_prev->ds_object;
 961                 dsl_dataset_rele(ds->ds_prev, ds);
 962                 ds->ds_prev = NULL;
 963         }
 964
 965         /*
 966          * This must be done after the dsl_traverse(), because it will
 967          * re-open the objset.
 968          */
 969         if (ds->ds_objset) {
 970                 dmu_objset_evict(ds->ds_objset);
 971                 ds->ds_objset = NULL;
 972         }
 973
 974         /* Erase the link in the dir */
 975         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 976         dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj = 0;
 977         ddobj = ds->ds_dir->dd_object;
 978         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0);
 979         VERIFY0(zap_destroy(mos,
 980             dsl_dataset_phys(ds)->ds_snapnames_zapobj, tx));
 981
 982         if (ds->ds_bookmarks != 0) {
 983                 VERIFY0(zap_destroy(mos, ds->ds_bookmarks, tx));
 984                 spa_feature_decr(dp->dp_spa, SPA_FEATURE_BOOKMARKS, tx);
 985         }
 986
 987         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 988
 989         ASSERT0(dsl_dataset_phys(ds)->ds_next_clones_obj);
 990         ASSERT0(dsl_dataset_phys(ds)->ds_props_obj);
 991         ASSERT0(dsl_dataset_phys(ds)->ds_userrefs_obj);
 992         dsl_dir_rele(ds->ds_dir, ds);
 993         ds->ds_dir = NULL;
 994         dmu_object_free_zapified(mos, obj, tx);
 995
 996         dsl_dir_destroy_sync(ddobj, tx);
 997
 998         if (rmorigin) {
 999                 dsl_dataset_t *prev;
1000                 VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
1001                 dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
1002                 dsl_dataset_rele(prev, FTAG);
1003         }
1004 }
1005
1006 void
1007 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
1008 {
1009         dsl_destroy_head_arg_t *ddha = arg;
1010         dsl_pool_t *dp = dmu_tx_pool(tx);
1011         dsl_dataset_t *ds;
1012
1013         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
1014         dsl_destroy_head_sync_impl(ds, tx);
1015         zvol_remove_minors(dp->dp_spa, ddha->ddha_name, B_TRUE);
1016         dsl_dataset_rele(ds, FTAG);
1017 }
1018
1019 static void
1020 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
1021 {
1022         dsl_destroy_head_arg_t *ddha = arg;
1023         dsl_pool_t *dp = dmu_tx_pool(tx);
1024         dsl_dataset_t *ds;
1025
1026         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
1027
1028         /* Mark it as inconsistent on-disk, in case we crash */
1029         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1030         dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
1031
1032         spa_history_log_internal_ds(ds, "destroy begin", tx, "");
1033         dsl_dataset_rele(ds, FTAG);
1034 }
1035
1036 int
1037 dsl_destroy_head(const char *name)
1038 {
1039         dsl_destroy_head_arg_t ddha;
1040         int error;
1041         spa_t *spa;
1042         boolean_t isenabled;
1043
1044 #ifdef _KERNEL
1045         zfs_destroy_unmount_origin(name);
1046 #endif
1047
1048         error = spa_open(name, &spa, FTAG);
1049         if (error != 0)
1050                 return (error);
1051         isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
1052         spa_close(spa, FTAG);
1053
1054         ddha.ddha_name = name;
1055
1056         if (!isenabled) {
1057                 objset_t *os;
1058
1059                 error = dsl_sync_task(name, dsl_destroy_head_check,
1060                     dsl_destroy_head_begin_sync, &ddha,
1061                     0, ZFS_SPACE_CHECK_DESTROY);
1062                 if (error != 0)
1063                         return (error);
1064
1065                 /*
1066                  * Head deletion is processed in one txg on old pools;
1067                  * remove the objects from open context so that the txg sync
1068                  * is not too long.
1069                  */
1070                 error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, B_FALSE,
1071                     FTAG, &os);
1072                 if (error == 0) {
1073                         uint64_t prev_snap_txg =
1074                             dsl_dataset_phys(dmu_objset_ds(os))->
1075                             ds_prev_snap_txg;
1076                         for (uint64_t obj = 0; error == 0;
1077                             error = dmu_object_next(os, &obj, FALSE,
1078                             prev_snap_txg))
1079                                 (void) dmu_free_long_object(os, obj);
1080                         /* sync out all frees */
1081                         txg_wait_synced(dmu_objset_pool(os), 0);
1082                         dmu_objset_disown(os, B_FALSE, FTAG);
1083                 }
1084         }
1085
1086         return (dsl_sync_task(name, dsl_destroy_head_check,
1087             dsl_destroy_head_sync, &ddha, 0, ZFS_SPACE_CHECK_DESTROY));
1088 }
1089
1090 /*
1091  * Note, this function is used as the callback for dmu_objset_find().  We
1092  * always return 0 so that we will continue to find and process
1093  * inconsistent datasets, even if we encounter an error trying to
1094  * process one of them.
1095  */
1096 /* ARGSUSED */
1097 int
1098 dsl_destroy_inconsistent(const char *dsname, void *arg)
1099 {
1100         objset_t *os;
1101
1102         if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
1103                 boolean_t need_destroy = DS_IS_INCONSISTENT(dmu_objset_ds(os));
1104
1105                 /*
1106                  * If the dataset is inconsistent because a resumable receive
1107                  * has failed, then do not destroy it.
1108                  */
1109                 if (dsl_dataset_has_resume_receive_state(dmu_objset_ds(os)))
1110                         need_destroy = B_FALSE;
1111
1112                 dmu_objset_rele(os, FTAG);
1113                 if (need_destroy)
1114                         (void) dsl_destroy_head(dsname);
1115         }
1116         return (0);
1117 }
1118
1119
1120 #if defined(_KERNEL)
1121 EXPORT_SYMBOL(dsl_destroy_head);
1122 EXPORT_SYMBOL(dsl_destroy_head_sync_impl);
1123 EXPORT_SYMBOL(dsl_dataset_user_hold_check_one);
1124 EXPORT_SYMBOL(dsl_destroy_snapshot_sync_impl);
1125 EXPORT_SYMBOL(dsl_destroy_inconsistent);
1126 EXPORT_SYMBOL(dsl_dataset_user_release_tmp);
1127 EXPORT_SYMBOL(dsl_destroy_head_check_impl);
1128 #endif