module/zfs/dsl_destroy.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, 2017 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(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 (ds->ds_feature_inuse[f]) {
 319                         dsl_dataset_deactivate_feature(obj, f, tx);
 320                         ds->ds_feature_inuse[f] = B_FALSE;
 321                 }
 322         }
 323         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 324                 ASSERT3P(ds->ds_prev, ==, NULL);
 325                 VERIFY0(dsl_dataset_hold_obj(dp,
 326                     dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &ds_prev));
 327                 after_branch_point =
 328                     (dsl_dataset_phys(ds_prev)->ds_next_snap_obj != obj);
 329
 330                 dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 331                 if (after_branch_point &&
 332                     dsl_dataset_phys(ds_prev)->ds_next_clones_obj != 0) {
 333                         dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
 334                         if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
 335                                 VERIFY0(zap_add_int(mos,
 336                                     dsl_dataset_phys(ds_prev)->
 337                                     ds_next_clones_obj,
 338                                     dsl_dataset_phys(ds)->ds_next_snap_obj,
 339                                     tx));
 340                         }
 341                 }
 342                 if (!after_branch_point) {
 343                         dsl_dataset_phys(ds_prev)->ds_next_snap_obj =
 344                             dsl_dataset_phys(ds)->ds_next_snap_obj;
 345                 }
 346         }
 347
 348         dsl_dataset_t *ds_next;
 349         uint64_t old_unique;
 350         uint64_t used = 0, comp = 0, uncomp = 0;
 351
 352         VERIFY0(dsl_dataset_hold_obj(dp,
 353             dsl_dataset_phys(ds)->ds_next_snap_obj, FTAG, &ds_next));
 354         ASSERT3U(dsl_dataset_phys(ds_next)->ds_prev_snap_obj, ==, obj);
 355
 356         old_unique = dsl_dataset_phys(ds_next)->ds_unique_bytes;
 357
 358         dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 359         dsl_dataset_phys(ds_next)->ds_prev_snap_obj =
 360             dsl_dataset_phys(ds)->ds_prev_snap_obj;
 361         dsl_dataset_phys(ds_next)->ds_prev_snap_txg =
 362             dsl_dataset_phys(ds)->ds_prev_snap_txg;
 363         ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
 364             ds_prev ? dsl_dataset_phys(ds_prev)->ds_creation_txg : 0);
 365
 366         if (ds_next->ds_deadlist.dl_oldfmt) {
 367                 process_old_deadlist(ds, ds_prev, ds_next,
 368                     after_branch_point, tx);
 369         } else {
 370                 /* Adjust prev's unique space. */
 371                 if (ds_prev && !after_branch_point) {
 372                         dsl_deadlist_space_range(&ds_next->ds_deadlist,
 373                             dsl_dataset_phys(ds_prev)->ds_prev_snap_txg,
 374                             dsl_dataset_phys(ds)->ds_prev_snap_txg,
 375                             &used, &comp, &uncomp);
 376                         dsl_dataset_phys(ds_prev)->ds_unique_bytes += used;
 377                 }
 378
 379                 /* Adjust snapused. */
 380                 dsl_deadlist_space_range(&ds_next->ds_deadlist,
 381                     dsl_dataset_phys(ds)->ds_prev_snap_txg, UINT64_MAX,
 382                     &used, &comp, &uncomp);
 383                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 384                     -used, -comp, -uncomp, tx);
 385
 386                 /* Move blocks to be freed to pool's free list. */
 387                 dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
 388                     &dp->dp_free_bpobj, dsl_dataset_phys(ds)->ds_prev_snap_txg,
 389                     tx);
 390                 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
 391                     DD_USED_HEAD, used, comp, uncomp, tx);
 392
 393                 /* Merge our deadlist into next's and free it. */
 394                 dsl_deadlist_merge(&ds_next->ds_deadlist,
 395                     dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 396         }
 397
 398         dsl_deadlist_close(&ds->ds_deadlist);
 399         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 400         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 401         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 402
 403         dsl_destroy_snapshot_handle_remaps(ds, ds_next, tx);
 404
 405         /* Collapse range in clone heads */
 406         dsl_dataset_remove_clones_key(ds,
 407             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 408
 409         if (ds_next->ds_is_snapshot) {
 410                 dsl_dataset_t *ds_nextnext;
 411
 412                 /*
 413                  * Update next's unique to include blocks which
 414                  * were previously shared by only this snapshot
 415                  * and it.  Those blocks will be born after the
 416                  * prev snap and before this snap, and will have
 417                  * died after the next snap and before the one
 418                  * after that (ie. be on the snap after next's
 419                  * deadlist).
 420                  */
 421                 VERIFY0(dsl_dataset_hold_obj(dp,
 422                     dsl_dataset_phys(ds_next)->ds_next_snap_obj,
 423                     FTAG, &ds_nextnext));
 424                 dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
 425                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 426                     dsl_dataset_phys(ds)->ds_creation_txg,
 427                     &used, &comp, &uncomp);
 428                 dsl_dataset_phys(ds_next)->ds_unique_bytes += used;
 429                 dsl_dataset_rele(ds_nextnext, FTAG);
 430                 ASSERT3P(ds_next->ds_prev, ==, NULL);
 431
 432                 /* Collapse range in this head. */
 433                 dsl_dataset_t *hds;
 434                 VERIFY0(dsl_dataset_hold_obj(dp,
 435                     dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &hds));
 436                 dsl_deadlist_remove_key(&hds->ds_deadlist,
 437                     dsl_dataset_phys(ds)->ds_creation_txg, tx);
 438                 if (dsl_dataset_remap_deadlist_exists(hds)) {
 439                         dsl_deadlist_remove_key(&hds->ds_remap_deadlist,
 440                             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 441                 }
 442                 dsl_dataset_rele(hds, FTAG);
 443
 444         } else {
 445                 ASSERT3P(ds_next->ds_prev, ==, ds);
 446                 dsl_dataset_rele(ds_next->ds_prev, ds_next);
 447                 ds_next->ds_prev = NULL;
 448                 if (ds_prev) {
 449                         VERIFY0(dsl_dataset_hold_obj(dp,
 450                             dsl_dataset_phys(ds)->ds_prev_snap_obj,
 451                             ds_next, &ds_next->ds_prev));
 452                 }
 453
 454                 dsl_dataset_recalc_head_uniq(ds_next);
 455
 456                 /*
 457                  * Reduce the amount of our unconsumed refreservation
 458                  * being charged to our parent by the amount of
 459                  * new unique data we have gained.
 460                  */
 461                 if (old_unique < ds_next->ds_reserved) {
 462                         int64_t mrsdelta;
 463                         uint64_t new_unique =
 464                             dsl_dataset_phys(ds_next)->ds_unique_bytes;
 465
 466                         ASSERT(old_unique <= new_unique);
 467                         mrsdelta = MIN(new_unique - old_unique,
 468                             ds_next->ds_reserved - old_unique);
 469                         dsl_dir_diduse_space(ds->ds_dir,
 470                             DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
 471                 }
 472         }
 473         dsl_dataset_rele(ds_next, FTAG);
 474
 475         /*
 476          * This must be done after the dsl_traverse(), because it will
 477          * re-open the objset.
 478          */
 479         if (ds->ds_objset) {
 480                 dmu_objset_evict(ds->ds_objset);
 481                 ds->ds_objset = NULL;
 482         }
 483
 484         /* remove from snapshot namespace */
 485         dsl_dataset_t *ds_head;
 486         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0);
 487         VERIFY0(dsl_dataset_hold_obj(dp,
 488             dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &ds_head));
 489         VERIFY0(dsl_dataset_get_snapname(ds));
 490 #ifdef ZFS_DEBUG
 491         {
 492                 uint64_t val;
 493                 int err;
 494
 495                 err = dsl_dataset_snap_lookup(ds_head,
 496                     ds->ds_snapname, &val);
 497                 ASSERT0(err);
 498                 ASSERT3U(val, ==, obj);
 499         }
 500 #endif
 501         VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx, B_TRUE));
 502         dsl_dataset_rele(ds_head, FTAG);
 503
 504         if (ds_prev != NULL)
 505                 dsl_dataset_rele(ds_prev, FTAG);
 506
 507         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 508
 509         if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
 510                 ASSERTV(uint64_t count);
 511                 ASSERT0(zap_count(mos,
 512                     dsl_dataset_phys(ds)->ds_next_clones_obj, &count) &&
 513                     count == 0);
 514                 VERIFY0(dmu_object_free(mos,
 515                     dsl_dataset_phys(ds)->ds_next_clones_obj, tx));
 516         }
 517         if (dsl_dataset_phys(ds)->ds_props_obj != 0)
 518                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_props_obj,
 519                     tx));
 520         if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0)
 521                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
 522                     tx));
 523         dsl_dir_rele(ds->ds_dir, ds);
 524         ds->ds_dir = NULL;
 525         dmu_object_free_zapified(mos, obj, tx);
 526 }
 527
 528 void
 529 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
 530 {
 531         dsl_destroy_snapshot_arg_t *ddsa = arg;
 532         const char *dsname = ddsa->ddsa_name;
 533         boolean_t defer = ddsa->ddsa_defer;
 534
 535         dsl_pool_t *dp = dmu_tx_pool(tx);
 536         dsl_dataset_t *ds;
 537
 538         int error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
 539         if (error == ENOENT)
 540                 return;
 541         ASSERT0(error);
 542         dsl_destroy_snapshot_sync_impl(ds, defer, tx);
 543         zvol_remove_minors(dp->dp_spa, dsname, B_TRUE);
 544         dsl_dataset_rele(ds, FTAG);
 545 }
 546
 547 /*
 548  * The semantics of this function are described in the comment above
 549  * lzc_destroy_snaps().  To summarize:
 550  *
 551  * The snapshots must all be in the same pool.
 552  *
 553  * Snapshots that don't exist will be silently ignored (considered to be
 554  * "already deleted").
 555  *
 556  * On success, all snaps will be destroyed and this will return 0.
 557  * On failure, no snaps will be destroyed, the errlist will be filled in,
 558  * and this will return an errno.
 559  */
 560 int
 561 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
 562     nvlist_t *errlist)
 563 {
 564         if (nvlist_next_nvpair(snaps, NULL) == NULL)
 565                 return (0);
 566
 567         /*
 568          * lzc_destroy_snaps() is documented to take an nvlist whose
 569          * values "don't matter".  We need to convert that nvlist to
 570          * one that we know can be converted to LUA. We also don't
 571          * care about any duplicate entries because the nvlist will
 572          * be converted to a LUA table which should take care of this.
 573          */
 574         nvlist_t *snaps_normalized;
 575         VERIFY0(nvlist_alloc(&snaps_normalized, 0, KM_SLEEP));
 576         for (nvpair_t *pair = nvlist_next_nvpair(snaps, NULL);
 577             pair != NULL; pair = nvlist_next_nvpair(snaps, pair)) {
 578                 fnvlist_add_boolean_value(snaps_normalized,
 579                     nvpair_name(pair), B_TRUE);
 580         }
 581
 582         nvlist_t *arg;
 583         VERIFY0(nvlist_alloc(&arg, 0, KM_SLEEP));
 584         fnvlist_add_nvlist(arg, "snaps", snaps_normalized);
 585         fnvlist_free(snaps_normalized);
 586         fnvlist_add_boolean_value(arg, "defer", defer);
 587
 588         nvlist_t *wrapper;
 589         VERIFY0(nvlist_alloc(&wrapper, 0, KM_SLEEP));
 590         fnvlist_add_nvlist(wrapper, ZCP_ARG_ARGLIST, arg);
 591         fnvlist_free(arg);
 592
 593         const char *program =
 594             "arg = ...\n"
 595             "snaps = arg['snaps']\n"
 596             "defer = arg['defer']\n"
 597             "errors = { }\n"
 598             "has_errors = false\n"
 599             "for snap, v in pairs(snaps) do\n"
 600             "    errno = zfs.check.destroy{snap, defer=defer}\n"
 601             "    zfs.debug('snap: ' .. snap .. ' errno: ' .. errno)\n"
 602             "    if errno == ENOENT then\n"
 603             "        snaps[snap] = nil\n"
 604             "    elseif errno ~= 0 then\n"
 605             "        errors[snap] = errno\n"
 606             "        has_errors = true\n"
 607             "    end\n"
 608             "end\n"
 609             "if has_errors then\n"
 610             "    return errors\n"
 611             "end\n"
 612             "for snap, v in pairs(snaps) do\n"
 613             "    errno = zfs.sync.destroy{snap, defer=defer}\n"
 614             "    assert(errno == 0)\n"
 615             "end\n"
 616             "return { }\n";
 617
 618         nvlist_t *result = fnvlist_alloc();
 619         int error = zcp_eval(nvpair_name(nvlist_next_nvpair(snaps, NULL)),
 620             program,
 621             B_TRUE,
 622             0,
 623             zfs_lua_max_memlimit,
 624             nvlist_next_nvpair(wrapper, NULL), result);
 625         if (error != 0) {
 626                 char *errorstr = NULL;
 627                 (void) nvlist_lookup_string(result, ZCP_RET_ERROR, &errorstr);
 628                 if (errorstr != NULL) {
 629                         zfs_dbgmsg(errorstr);
 630                 }
 631                 return (error);
 632         }
 633         fnvlist_free(wrapper);
 634
 635         /*
 636          * lzc_destroy_snaps() is documented to fill the errlist with
 637          * int32 values, so we need to covert the int64 values that are
 638          * returned from LUA.
 639          */
 640         int rv = 0;
 641         nvlist_t *errlist_raw = fnvlist_lookup_nvlist(result, ZCP_RET_RETURN);
 642         for (nvpair_t *pair = nvlist_next_nvpair(errlist_raw, NULL);
 643             pair != NULL; pair = nvlist_next_nvpair(errlist_raw, pair)) {
 644                 int32_t val = (int32_t)fnvpair_value_int64(pair);
 645                 if (rv == 0)
 646                         rv = val;
 647                 fnvlist_add_int32(errlist, nvpair_name(pair), val);
 648         }
 649         fnvlist_free(result);
 650         return (rv);
 651 }
 652
 653 int
 654 dsl_destroy_snapshot(const char *name, boolean_t defer)
 655 {
 656         int error;
 657         nvlist_t *nvl = fnvlist_alloc();
 658         nvlist_t *errlist = fnvlist_alloc();
 659
 660         fnvlist_add_boolean(nvl, name);
 661         error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
 662         fnvlist_free(errlist);
 663         fnvlist_free(nvl);
 664         return (error);
 665 }
 666
 667 struct killarg {
 668         dsl_dataset_t *ds;
 669         dmu_tx_t *tx;
 670 };
 671
 672 /* ARGSUSED */
 673 static int
 674 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 675     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 676 {
 677         struct killarg *ka = arg;
 678         dmu_tx_t *tx = ka->tx;
 679
 680         if (bp == NULL || BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
 681                 return (0);
 682
 683         if (zb->zb_level == ZB_ZIL_LEVEL) {
 684                 ASSERT(zilog != NULL);
 685                 /*
 686                  * It's a block in the intent log.  It has no
 687                  * accounting, so just free it.
 688                  */
 689                 dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
 690         } else {
 691                 ASSERT(zilog == NULL);
 692                 ASSERT3U(bp->blk_birth, >,
 693                     dsl_dataset_phys(ka->ds)->ds_prev_snap_txg);
 694                 (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
 695         }
 696
 697         return (0);
 698 }
 699
 700 static void
 701 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 702 {
 703         struct killarg ka;
 704
 705         /*
 706          * Free everything that we point to (that's born after
 707          * the previous snapshot, if we are a clone)
 708          *
 709          * NB: this should be very quick, because we already
 710          * freed all the objects in open context.
 711          */
 712         ka.ds = ds;
 713         ka.tx = tx;
 714         VERIFY0(traverse_dataset(ds,
 715             dsl_dataset_phys(ds)->ds_prev_snap_txg, TRAVERSE_POST |
 716             TRAVERSE_NO_DECRYPT, kill_blkptr, &ka));
 717         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 718             dsl_dataset_phys(ds)->ds_unique_bytes == 0);
 719 }
 720
 721 int
 722 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
 723 {
 724         int error;
 725         uint64_t count;
 726         objset_t *mos;
 727
 728         ASSERT(!ds->ds_is_snapshot);
 729         if (ds->ds_is_snapshot)
 730                 return (SET_ERROR(EINVAL));
 731
 732         if (refcount_count(&ds->ds_longholds) != expected_holds)
 733                 return (SET_ERROR(EBUSY));
 734
 735         mos = ds->ds_dir->dd_pool->dp_meta_objset;
 736
 737         /*
 738          * Can't delete a head dataset if there are snapshots of it.
 739          * (Except if the only snapshots are from the branch we cloned
 740          * from.)
 741          */
 742         if (ds->ds_prev != NULL &&
 743             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj == ds->ds_object)
 744                 return (SET_ERROR(EBUSY));
 745
 746         /*
 747          * Can't delete if there are children of this fs.
 748          */
 749         error = zap_count(mos,
 750             dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, &count);
 751         if (error != 0)
 752                 return (error);
 753         if (count != 0)
 754                 return (SET_ERROR(EEXIST));
 755
 756         if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 757             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 758             ds->ds_prev->ds_userrefs == 0) {
 759                 /* We need to remove the origin snapshot as well. */
 760                 if (!refcount_is_zero(&ds->ds_prev->ds_longholds))
 761                         return (SET_ERROR(EBUSY));
 762         }
 763         return (0);
 764 }
 765
 766 int
 767 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
 768 {
 769         dsl_destroy_head_arg_t *ddha = arg;
 770         dsl_pool_t *dp = dmu_tx_pool(tx);
 771         dsl_dataset_t *ds;
 772         int error;
 773
 774         error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
 775         if (error != 0)
 776                 return (error);
 777
 778         error = dsl_destroy_head_check_impl(ds, 0);
 779         dsl_dataset_rele(ds, FTAG);
 780         return (error);
 781 }
 782
 783 static void
 784 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
 785 {
 786         dsl_dir_t *dd;
 787         dsl_pool_t *dp = dmu_tx_pool(tx);
 788         objset_t *mos = dp->dp_meta_objset;
 789         dd_used_t t;
 790
 791         ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
 792
 793         VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
 794
 795         ASSERT0(dsl_dir_phys(dd)->dd_head_dataset_obj);
 796
 797         /*
 798          * Decrement the filesystem count for all parent filesystems.
 799          *
 800          * When we receive an incremental stream into a filesystem that already
 801          * exists, a temporary clone is created.  We never count this temporary
 802          * clone, whose name begins with a '%'.
 803          */
 804         if (dd->dd_myname[0] != '%' && dd->dd_parent != NULL)
 805                 dsl_fs_ss_count_adjust(dd->dd_parent, -1,
 806                     DD_FIELD_FILESYSTEM_COUNT, tx);
 807
 808         /*
 809          * Remove our reservation. The impl() routine avoids setting the
 810          * actual property, which would require the (already destroyed) ds.
 811          */
 812         dsl_dir_set_reservation_sync_impl(dd, 0, tx);
 813
 814         ASSERT0(dsl_dir_phys(dd)->dd_used_bytes);
 815         ASSERT0(dsl_dir_phys(dd)->dd_reserved);
 816         for (t = 0; t < DD_USED_NUM; t++)
 817                 ASSERT0(dsl_dir_phys(dd)->dd_used_breakdown[t]);
 818
 819         if (dd->dd_crypto_obj != 0) {
 820                 dsl_crypto_key_destroy_sync(dd->dd_crypto_obj, tx);
 821                 (void) spa_keystore_unload_wkey_impl(dp->dp_spa, dd->dd_object);
 822         }
 823
 824         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_child_dir_zapobj, tx));
 825         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_props_zapobj, 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 (ds->ds_feature_inuse[f]) {
 871                         dsl_dataset_deactivate_feature(obj, f, tx);
 872                         ds->ds_feature_inuse[f] = B_FALSE;
 873                 }
 874         }
 875
 876         dsl_scan_ds_destroyed(ds, tx);
 877
 878         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 879                 /* This is a clone */
 880                 ASSERT(ds->ds_prev != NULL);
 881                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj, !=,
 882                     obj);
 883                 ASSERT0(dsl_dataset_phys(ds)->ds_next_snap_obj);
 884
 885                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 886                 if (dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj != 0) {
 887                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
 888                             obj, tx);
 889                 }
 890
 891                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_num_children, >, 1);
 892                 dsl_dataset_phys(ds->ds_prev)->ds_num_children--;
 893         }
 894
 895         /*
 896          * Destroy the deadlist.  Unless it's a clone, the
 897          * deadlist should be empty since the dataset has no snapshots.
 898          * (If it's a clone, it's safe to ignore the deadlist contents
 899          * since they are still referenced by the origin snapshot.)
 900          */
 901         dsl_deadlist_close(&ds->ds_deadlist);
 902         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 903         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 904         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 905
 906         if (dsl_dataset_remap_deadlist_exists(ds))
 907                 dsl_dataset_destroy_remap_deadlist(ds, tx);
 908
 909         objset_t *os;
 910         VERIFY0(dmu_objset_from_ds(ds, &os));
 911
 912         if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
 913                 old_synchronous_dataset_destroy(ds, tx);
 914         } else {
 915                 /*
 916                  * Move the bptree into the pool's list of trees to
 917                  * clean up and update space accounting information.
 918                  */
 919                 uint64_t used, comp, uncomp;
 920
 921                 zil_destroy_sync(dmu_objset_zil(os), tx);
 922
 923                 if (!spa_feature_is_active(dp->dp_spa,
 924                     SPA_FEATURE_ASYNC_DESTROY)) {
 925                         dsl_scan_t *scn = dp->dp_scan;
 926                         spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
 927                             tx);
 928                         dp->dp_bptree_obj = bptree_alloc(mos, tx);
 929                         VERIFY0(zap_add(mos,
 930                             DMU_POOL_DIRECTORY_OBJECT,
 931                             DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
 932                             &dp->dp_bptree_obj, tx));
 933                         ASSERT(!scn->scn_async_destroying);
 934                         scn->scn_async_destroying = B_TRUE;
 935                 }
 936
 937                 used = dsl_dir_phys(ds->ds_dir)->dd_used_bytes;
 938                 comp = dsl_dir_phys(ds->ds_dir)->dd_compressed_bytes;
 939                 uncomp = dsl_dir_phys(ds->ds_dir)->dd_uncompressed_bytes;
 940
 941                 ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 942                     dsl_dataset_phys(ds)->ds_unique_bytes == used);
 943
 944                 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
 945                 bptree_add(mos, dp->dp_bptree_obj,
 946                     &dsl_dataset_phys(ds)->ds_bp,
 947                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 948                     used, comp, uncomp, tx);
 949                 rrw_exit(&ds->ds_bp_rwlock, FTAG);
 950                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 951                     -used, -comp, -uncomp, tx);
 952                 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
 953                     used, comp, uncomp, tx);
 954         }
 955
 956         if (ds->ds_prev != NULL) {
 957                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 958                         VERIFY0(zap_remove_int(mos,
 959                             dsl_dir_phys(ds->ds_prev->ds_dir)->dd_clones,
 960                             ds->ds_object, tx));
 961                 }
 962                 prevobj = ds->ds_prev->ds_object;
 963                 dsl_dataset_rele(ds->ds_prev, ds);
 964                 ds->ds_prev = NULL;
 965         }
 966
 967         /*
 968          * This must be done after the dsl_traverse(), because it will
 969          * re-open the objset.
 970          */
 971         if (ds->ds_objset) {
 972                 dmu_objset_evict(ds->ds_objset);
 973                 ds->ds_objset = NULL;
 974         }
 975
 976         /* Erase the link in the dir */
 977         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 978         dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj = 0;
 979         ddobj = ds->ds_dir->dd_object;
 980         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0);
 981         VERIFY0(zap_destroy(mos,
 982             dsl_dataset_phys(ds)->ds_snapnames_zapobj, tx));
 983
 984         if (ds->ds_bookmarks != 0) {
 985                 VERIFY0(zap_destroy(mos, ds->ds_bookmarks, tx));
 986                 spa_feature_decr(dp->dp_spa, SPA_FEATURE_BOOKMARKS, tx);
 987         }
 988
 989         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 990
 991         ASSERT0(dsl_dataset_phys(ds)->ds_next_clones_obj);
 992         ASSERT0(dsl_dataset_phys(ds)->ds_props_obj);
 993         ASSERT0(dsl_dataset_phys(ds)->ds_userrefs_obj);
 994         dsl_dir_rele(ds->ds_dir, ds);
 995         ds->ds_dir = NULL;
 996         dmu_object_free_zapified(mos, obj, tx);
 997
 998         dsl_dir_destroy_sync(ddobj, tx);
 999
1000         if (rmorigin) {
1001                 dsl_dataset_t *prev;
1002                 VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
1003                 dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
1004                 dsl_dataset_rele(prev, FTAG);
1005         }
1006 }
1007
1008 void
1009 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
1010 {
1011         dsl_destroy_head_arg_t *ddha = arg;
1012         dsl_pool_t *dp = dmu_tx_pool(tx);
1013         dsl_dataset_t *ds;
1014
1015         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
1016         dsl_destroy_head_sync_impl(ds, tx);
1017         zvol_remove_minors(dp->dp_spa, ddha->ddha_name, B_TRUE);
1018         dsl_dataset_rele(ds, FTAG);
1019 }
1020
1021 static void
1022 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
1023 {
1024         dsl_destroy_head_arg_t *ddha = arg;
1025         dsl_pool_t *dp = dmu_tx_pool(tx);
1026         dsl_dataset_t *ds;
1027
1028         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
1029
1030         /* Mark it as inconsistent on-disk, in case we crash */
1031         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1032         dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
1033
1034         spa_history_log_internal_ds(ds, "destroy begin", tx, "");
1035         dsl_dataset_rele(ds, FTAG);
1036 }
1037
1038 int
1039 dsl_destroy_head(const char *name)
1040 {
1041         dsl_destroy_head_arg_t ddha;
1042         int error;
1043         spa_t *spa;
1044         boolean_t isenabled;
1045
1046 #ifdef _KERNEL
1047         zfs_destroy_unmount_origin(name);
1048 #endif
1049
1050         error = spa_open(name, &spa, FTAG);
1051         if (error != 0)
1052                 return (error);
1053         isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
1054         spa_close(spa, FTAG);
1055
1056         ddha.ddha_name = name;
1057
1058         if (!isenabled) {
1059                 objset_t *os;
1060
1061                 error = dsl_sync_task(name, dsl_destroy_head_check,
1062                     dsl_destroy_head_begin_sync, &ddha,
1063                     0, ZFS_SPACE_CHECK_DESTROY);
1064                 if (error != 0)
1065                         return (error);
1066
1067                 /*
1068                  * Head deletion is processed in one txg on old pools;
1069                  * remove the objects from open context so that the txg sync
1070                  * is not too long.
1071                  */
1072                 error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, B_FALSE,
1073                     FTAG, &os);
1074                 if (error == 0) {
1075                         uint64_t prev_snap_txg =
1076                             dsl_dataset_phys(dmu_objset_ds(os))->
1077                             ds_prev_snap_txg;
1078                         for (uint64_t obj = 0; error == 0;
1079                             error = dmu_object_next(os, &obj, FALSE,
1080                             prev_snap_txg))
1081                                 (void) dmu_free_long_object(os, obj);
1082                         /* sync out all frees */
1083                         txg_wait_synced(dmu_objset_pool(os), 0);
1084                         dmu_objset_disown(os, B_FALSE, FTAG);
1085                 }
1086         }
1087
1088         return (dsl_sync_task(name, dsl_destroy_head_check,
1089             dsl_destroy_head_sync, &ddha, 0, ZFS_SPACE_CHECK_DESTROY));
1090 }
1091
1092 /*
1093  * Note, this function is used as the callback for dmu_objset_find().  We
1094  * always return 0 so that we will continue to find and process
1095  * inconsistent datasets, even if we encounter an error trying to
1096  * process one of them.
1097  */
1098 /* ARGSUSED */
1099 int
1100 dsl_destroy_inconsistent(const char *dsname, void *arg)
1101 {
1102         objset_t *os;
1103
1104         if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
1105                 boolean_t need_destroy = DS_IS_INCONSISTENT(dmu_objset_ds(os));
1106
1107                 /*
1108                  * If the dataset is inconsistent because a resumable receive
1109                  * has failed, then do not destroy it.
1110                  */
1111                 if (dsl_dataset_has_resume_receive_state(dmu_objset_ds(os)))
1112                         need_destroy = B_FALSE;
1113
1114                 dmu_objset_rele(os, FTAG);
1115                 if (need_destroy)
1116                         (void) dsl_destroy_head(dsname);
1117         }
1118         return (0);
1119 }
1120
1121
1122 #if defined(_KERNEL)
1123 EXPORT_SYMBOL(dsl_destroy_head);
1124 EXPORT_SYMBOL(dsl_destroy_head_sync_impl);
1125 EXPORT_SYMBOL(dsl_dataset_user_hold_check_one);
1126 EXPORT_SYMBOL(dsl_destroy_snapshot_sync_impl);
1127 EXPORT_SYMBOL(dsl_destroy_inconsistent);
1128 EXPORT_SYMBOL(dsl_dataset_user_release_tmp);
1129 EXPORT_SYMBOL(dsl_destroy_head_check_impl);
1130 #endif