sys/cddl/contrib/opensolaris/uts/common/fs/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, 2014 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  */
  27
  28 #include <sys/zfs_context.h>
  29 #include <sys/dsl_userhold.h>
  30 #include <sys/dsl_dataset.h>
  31 #include <sys/dsl_synctask.h>
  32 #include <sys/dmu_tx.h>
  33 #include <sys/dsl_pool.h>
  34 #include <sys/dsl_dir.h>
  35 #include <sys/dmu_traverse.h>
  36 #include <sys/dsl_scan.h>
  37 #include <sys/dmu_objset.h>
  38 #include <sys/zap.h>
  39 #include <sys/zfeature.h>
  40 #include <sys/zfs_ioctl.h>
  41 #include <sys/dsl_deleg.h>
  42 #include <sys/dmu_impl.h>
  43
  44 typedef struct dmu_snapshots_destroy_arg {
  45         nvlist_t *dsda_snaps;
  46         nvlist_t *dsda_successful_snaps;
  47         boolean_t dsda_defer;
  48         nvlist_t *dsda_errlist;
  49 } dmu_snapshots_destroy_arg_t;
  50
  51 int
  52 dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
  53 {
  54         if (!dsl_dataset_is_snapshot(ds))
  55                 return (SET_ERROR(EINVAL));
  56
  57         if (dsl_dataset_long_held(ds))
  58                 return (SET_ERROR(EBUSY));
  59
  60         /*
  61          * Only allow deferred destroy on pools that support it.
  62          * NOTE: deferred destroy is only supported on snapshots.
  63          */
  64         if (defer) {
  65                 if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
  66                     SPA_VERSION_USERREFS)
  67                         return (SET_ERROR(ENOTSUP));
  68                 return (0);
  69         }
  70
  71         /*
  72          * If this snapshot has an elevated user reference count,
  73          * we can't destroy it yet.
  74          */
  75         if (ds->ds_userrefs > 0)
  76                 return (SET_ERROR(EBUSY));
  77
  78         /*
  79          * Can't delete a branch point.
  80          */
  81         if (dsl_dataset_phys(ds)->ds_num_children > 1)
  82                 return (SET_ERROR(EEXIST));
  83
  84         return (0);
  85 }
  86
  87 static int
  88 dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
  89 {
  90         dmu_snapshots_destroy_arg_t *dsda = arg;
  91         dsl_pool_t *dp = dmu_tx_pool(tx);
  92         nvpair_t *pair;
  93         int error = 0;
  94
  95         if (!dmu_tx_is_syncing(tx))
  96                 return (0);
  97
  98         for (pair = nvlist_next_nvpair(dsda->dsda_snaps, NULL);
  99             pair != NULL; pair = nvlist_next_nvpair(dsda->dsda_snaps, pair)) {
 100                 dsl_dataset_t *ds;
 101
 102                 error = dsl_dataset_hold(dp, nvpair_name(pair),
 103                     FTAG, &ds);
 104
 105                 /*
 106                  * If the snapshot does not exist, silently ignore it
 107                  * (it's "already destroyed").
 108                  */
 109                 if (error == ENOENT)
 110                         continue;
 111
 112                 if (error == 0) {
 113                         error = dsl_destroy_snapshot_check_impl(ds,
 114                             dsda->dsda_defer);
 115                         dsl_dataset_rele(ds, FTAG);
 116                 }
 117
 118                 if (error == 0) {
 119                         fnvlist_add_boolean(dsda->dsda_successful_snaps,
 120                             nvpair_name(pair));
 121                 } else {
 122                         fnvlist_add_int32(dsda->dsda_errlist,
 123                             nvpair_name(pair), error);
 124                 }
 125         }
 126
 127         pair = nvlist_next_nvpair(dsda->dsda_errlist, NULL);
 128         if (pair != NULL)
 129                 return (fnvpair_value_int32(pair));
 130
 131         return (0);
 132 }
 133
 134 struct process_old_arg {
 135         dsl_dataset_t *ds;
 136         dsl_dataset_t *ds_prev;
 137         boolean_t after_branch_point;
 138         zio_t *pio;
 139         uint64_t used, comp, uncomp;
 140 };
 141
 142 static int
 143 process_old_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 144 {
 145         struct process_old_arg *poa = arg;
 146         dsl_pool_t *dp = poa->ds->ds_dir->dd_pool;
 147
 148         ASSERT(!BP_IS_HOLE(bp));
 149
 150         if (bp->blk_birth <= dsl_dataset_phys(poa->ds)->ds_prev_snap_txg) {
 151                 dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, tx);
 152                 if (poa->ds_prev && !poa->after_branch_point &&
 153                     bp->blk_birth >
 154                     dsl_dataset_phys(poa->ds_prev)->ds_prev_snap_txg) {
 155                         dsl_dataset_phys(poa->ds_prev)->ds_unique_bytes +=
 156                             bp_get_dsize_sync(dp->dp_spa, bp);
 157                 }
 158         } else {
 159                 poa->used += bp_get_dsize_sync(dp->dp_spa, bp);
 160                 poa->comp += BP_GET_PSIZE(bp);
 161                 poa->uncomp += BP_GET_UCSIZE(bp);
 162                 dsl_free_sync(poa->pio, dp, tx->tx_txg, bp);
 163         }
 164         return (0);
 165 }
 166
 167 static void
 168 process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev,
 169     dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx)
 170 {
 171         struct process_old_arg poa = { 0 };
 172         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 173         objset_t *mos = dp->dp_meta_objset;
 174         uint64_t deadlist_obj;
 175
 176         ASSERT(ds->ds_deadlist.dl_oldfmt);
 177         ASSERT(ds_next->ds_deadlist.dl_oldfmt);
 178
 179         poa.ds = ds;
 180         poa.ds_prev = ds_prev;
 181         poa.after_branch_point = after_branch_point;
 182         poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 183         VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
 184             process_old_cb, &poa, tx));
 185         VERIFY0(zio_wait(poa.pio));
 186         ASSERT3U(poa.used, ==, dsl_dataset_phys(ds)->ds_unique_bytes);
 187
 188         /* change snapused */
 189         dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 190             -poa.used, -poa.comp, -poa.uncomp, tx);
 191
 192         /* swap next's deadlist to our deadlist */
 193         dsl_deadlist_close(&ds->ds_deadlist);
 194         dsl_deadlist_close(&ds_next->ds_deadlist);
 195         deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
 196         dsl_dataset_phys(ds)->ds_deadlist_obj =
 197             dsl_dataset_phys(ds_next)->ds_deadlist_obj;
 198         dsl_dataset_phys(ds_next)->ds_deadlist_obj = deadlist_obj;
 199         dsl_deadlist_open(&ds->ds_deadlist, mos,
 200             dsl_dataset_phys(ds)->ds_deadlist_obj);
 201         dsl_deadlist_open(&ds_next->ds_deadlist, mos,
 202             dsl_dataset_phys(ds_next)->ds_deadlist_obj);
 203 }
 204
 205 static void
 206 dsl_dataset_remove_clones_key(dsl_dataset_t *ds, uint64_t mintxg, dmu_tx_t *tx)
 207 {
 208         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 209         zap_cursor_t zc;
 210         zap_attribute_t za;
 211
 212         /*
 213          * If it is the old version, dd_clones doesn't exist so we can't
 214          * find the clones, but dsl_deadlist_remove_key() is a no-op so it
 215          * doesn't matter.
 216          */
 217         if (dsl_dir_phys(ds->ds_dir)->dd_clones == 0)
 218                 return;
 219
 220         for (zap_cursor_init(&zc, mos, dsl_dir_phys(ds->ds_dir)->dd_clones);
 221             zap_cursor_retrieve(&zc, &za) == 0;
 222             zap_cursor_advance(&zc)) {
 223                 dsl_dataset_t *clone;
 224
 225                 VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
 226                     za.za_first_integer, FTAG, &clone));
 227                 if (clone->ds_dir->dd_origin_txg > mintxg) {
 228                         dsl_deadlist_remove_key(&clone->ds_deadlist,
 229                             mintxg, tx);
 230                         dsl_dataset_remove_clones_key(clone, mintxg, tx);
 231                 }
 232                 dsl_dataset_rele(clone, FTAG);
 233         }
 234         zap_cursor_fini(&zc);
 235 }
 236
 237 void
 238 dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 239 {
 240         int err;
 241         int after_branch_point = FALSE;
 242         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 243         objset_t *mos = dp->dp_meta_objset;
 244         dsl_dataset_t *ds_prev = NULL;
 245         uint64_t obj;
 246
 247         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 248         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
 249         ASSERT(refcount_is_zero(&ds->ds_longholds));
 250
 251         if (defer &&
 252             (ds->ds_userrefs > 0 ||
 253             dsl_dataset_phys(ds)->ds_num_children > 1)) {
 254                 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
 255                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 256                 dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_DEFER_DESTROY;
 257                 spa_history_log_internal_ds(ds, "defer_destroy", tx, "");
 258                 return;
 259         }
 260
 261         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
 262
 263         /* We need to log before removing it from the namespace. */
 264         spa_history_log_internal_ds(ds, "destroy", tx, "");
 265
 266         dsl_scan_ds_destroyed(ds, tx);
 267
 268         obj = ds->ds_object;
 269
 270         if (ds->ds_large_blocks) {
 271                 ASSERT0(zap_contains(mos, obj, DS_FIELD_LARGE_BLOCKS));
 272                 spa_feature_decr(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS, tx);
 273         }
 274         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 275                 ASSERT3P(ds->ds_prev, ==, NULL);
 276                 VERIFY0(dsl_dataset_hold_obj(dp,
 277                     dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &ds_prev));
 278                 after_branch_point =
 279                     (dsl_dataset_phys(ds_prev)->ds_next_snap_obj != obj);
 280
 281                 dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 282                 if (after_branch_point &&
 283                     dsl_dataset_phys(ds_prev)->ds_next_clones_obj != 0) {
 284                         dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
 285                         if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
 286                                 VERIFY0(zap_add_int(mos,
 287                                     dsl_dataset_phys(ds_prev)->
 288                                     ds_next_clones_obj,
 289                                     dsl_dataset_phys(ds)->ds_next_snap_obj,
 290                                     tx));
 291                         }
 292                 }
 293                 if (!after_branch_point) {
 294                         dsl_dataset_phys(ds_prev)->ds_next_snap_obj =
 295                             dsl_dataset_phys(ds)->ds_next_snap_obj;
 296                 }
 297         }
 298
 299         dsl_dataset_t *ds_next;
 300         uint64_t old_unique;
 301         uint64_t used = 0, comp = 0, uncomp = 0;
 302
 303         VERIFY0(dsl_dataset_hold_obj(dp,
 304             dsl_dataset_phys(ds)->ds_next_snap_obj, FTAG, &ds_next));
 305         ASSERT3U(dsl_dataset_phys(ds_next)->ds_prev_snap_obj, ==, obj);
 306
 307         old_unique = dsl_dataset_phys(ds_next)->ds_unique_bytes;
 308
 309         dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 310         dsl_dataset_phys(ds_next)->ds_prev_snap_obj =
 311             dsl_dataset_phys(ds)->ds_prev_snap_obj;
 312         dsl_dataset_phys(ds_next)->ds_prev_snap_txg =
 313             dsl_dataset_phys(ds)->ds_prev_snap_txg;
 314         ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
 315             ds_prev ? dsl_dataset_phys(ds_prev)->ds_creation_txg : 0);
 316
 317         if (ds_next->ds_deadlist.dl_oldfmt) {
 318                 process_old_deadlist(ds, ds_prev, ds_next,
 319                     after_branch_point, tx);
 320         } else {
 321                 /* Adjust prev's unique space. */
 322                 if (ds_prev && !after_branch_point) {
 323                         dsl_deadlist_space_range(&ds_next->ds_deadlist,
 324                             dsl_dataset_phys(ds_prev)->ds_prev_snap_txg,
 325                             dsl_dataset_phys(ds)->ds_prev_snap_txg,
 326                             &used, &comp, &uncomp);
 327                         dsl_dataset_phys(ds_prev)->ds_unique_bytes += used;
 328                 }
 329
 330                 /* Adjust snapused. */
 331                 dsl_deadlist_space_range(&ds_next->ds_deadlist,
 332                     dsl_dataset_phys(ds)->ds_prev_snap_txg, UINT64_MAX,
 333                     &used, &comp, &uncomp);
 334                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 335                     -used, -comp, -uncomp, tx);
 336
 337                 /* Move blocks to be freed to pool's free list. */
 338                 dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
 339                     &dp->dp_free_bpobj, dsl_dataset_phys(ds)->ds_prev_snap_txg,
 340                     tx);
 341                 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
 342                     DD_USED_HEAD, used, comp, uncomp, tx);
 343
 344                 /* Merge our deadlist into next's and free it. */
 345                 dsl_deadlist_merge(&ds_next->ds_deadlist,
 346                     dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 347         }
 348         dsl_deadlist_close(&ds->ds_deadlist);
 349         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 350         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 351         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 352
 353         /* Collapse range in clone heads */
 354         dsl_dataset_remove_clones_key(ds,
 355             dsl_dataset_phys(ds)->ds_creation_txg, tx);
 356
 357         if (dsl_dataset_is_snapshot(ds_next)) {
 358                 dsl_dataset_t *ds_nextnext;
 359
 360                 /*
 361                  * Update next's unique to include blocks which
 362                  * were previously shared by only this snapshot
 363                  * and it.  Those blocks will be born after the
 364                  * prev snap and before this snap, and will have
 365                  * died after the next snap and before the one
 366                  * after that (ie. be on the snap after next's
 367                  * deadlist).
 368                  */
 369                 VERIFY0(dsl_dataset_hold_obj(dp,
 370                     dsl_dataset_phys(ds_next)->ds_next_snap_obj,
 371                     FTAG, &ds_nextnext));
 372                 dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
 373                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 374                     dsl_dataset_phys(ds)->ds_creation_txg,
 375                     &used, &comp, &uncomp);
 376                 dsl_dataset_phys(ds_next)->ds_unique_bytes += used;
 377                 dsl_dataset_rele(ds_nextnext, FTAG);
 378                 ASSERT3P(ds_next->ds_prev, ==, NULL);
 379
 380                 /* Collapse range in this head. */
 381                 dsl_dataset_t *hds;
 382                 VERIFY0(dsl_dataset_hold_obj(dp,
 383                     dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &hds));
 384                 dsl_deadlist_remove_key(&hds->ds_deadlist,
 385                     dsl_dataset_phys(ds)->ds_creation_txg, tx);
 386                 dsl_dataset_rele(hds, FTAG);
 387
 388         } else {
 389                 ASSERT3P(ds_next->ds_prev, ==, ds);
 390                 dsl_dataset_rele(ds_next->ds_prev, ds_next);
 391                 ds_next->ds_prev = NULL;
 392                 if (ds_prev) {
 393                         VERIFY0(dsl_dataset_hold_obj(dp,
 394                             dsl_dataset_phys(ds)->ds_prev_snap_obj,
 395                             ds_next, &ds_next->ds_prev));
 396                 }
 397
 398                 dsl_dataset_recalc_head_uniq(ds_next);
 399
 400                 /*
 401                  * Reduce the amount of our unconsumed refreservation
 402                  * being charged to our parent by the amount of
 403                  * new unique data we have gained.
 404                  */
 405                 if (old_unique < ds_next->ds_reserved) {
 406                         int64_t mrsdelta;
 407                         uint64_t new_unique =
 408                             dsl_dataset_phys(ds_next)->ds_unique_bytes;
 409
 410                         ASSERT(old_unique <= new_unique);
 411                         mrsdelta = MIN(new_unique - old_unique,
 412                             ds_next->ds_reserved - old_unique);
 413                         dsl_dir_diduse_space(ds->ds_dir,
 414                             DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
 415                 }
 416         }
 417         dsl_dataset_rele(ds_next, FTAG);
 418
 419         /*
 420          * This must be done after the dsl_traverse(), because it will
 421          * re-open the objset.
 422          */
 423         if (ds->ds_objset) {
 424                 dmu_objset_evict(ds->ds_objset);
 425                 ds->ds_objset = NULL;
 426         }
 427
 428         /* remove from snapshot namespace */
 429         dsl_dataset_t *ds_head;
 430         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0);
 431         VERIFY0(dsl_dataset_hold_obj(dp,
 432             dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &ds_head));
 433         VERIFY0(dsl_dataset_get_snapname(ds));
 434 #ifdef ZFS_DEBUG
 435         {
 436                 uint64_t val;
 437
 438                 err = dsl_dataset_snap_lookup(ds_head,
 439                     ds->ds_snapname, &val);
 440                 ASSERT0(err);
 441                 ASSERT3U(val, ==, obj);
 442         }
 443 #endif
 444         VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx, B_TRUE));
 445         dsl_dataset_rele(ds_head, FTAG);
 446
 447         if (ds_prev != NULL)
 448                 dsl_dataset_rele(ds_prev, FTAG);
 449
 450         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 451
 452         if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
 453                 uint64_t count;
 454                 ASSERT0(zap_count(mos,
 455                     dsl_dataset_phys(ds)->ds_next_clones_obj, &count) &&
 456                     count == 0);
 457                 VERIFY0(dmu_object_free(mos,
 458                     dsl_dataset_phys(ds)->ds_next_clones_obj, tx));
 459         }
 460         if (dsl_dataset_phys(ds)->ds_props_obj != 0)
 461                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_props_obj,
 462                     tx));
 463         if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0)
 464                 VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
 465                     tx));
 466         dsl_dir_rele(ds->ds_dir, ds);
 467         ds->ds_dir = NULL;
 468         dmu_object_free_zapified(mos, obj, tx);
 469 }
 470
 471 static void
 472 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
 473 {
 474         dmu_snapshots_destroy_arg_t *dsda = arg;
 475         dsl_pool_t *dp = dmu_tx_pool(tx);
 476         nvpair_t *pair;
 477
 478         for (pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, NULL);
 479             pair != NULL;
 480             pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, pair)) {
 481                 dsl_dataset_t *ds;
 482
 483                 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
 484
 485                 dsl_destroy_snapshot_sync_impl(ds, dsda->dsda_defer, tx);
 486                 dsl_dataset_rele(ds, FTAG);
 487         }
 488 }
 489
 490 /*
 491  * The semantics of this function are described in the comment above
 492  * lzc_destroy_snaps().  To summarize:
 493  *
 494  * The snapshots must all be in the same pool.
 495  *
 496  * Snapshots that don't exist will be silently ignored (considered to be
 497  * "already deleted").
 498  *
 499  * On success, all snaps will be destroyed and this will return 0.
 500  * On failure, no snaps will be destroyed, the errlist will be filled in,
 501  * and this will return an errno.
 502  */
 503 int
 504 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
 505     nvlist_t *errlist)
 506 {
 507         dmu_snapshots_destroy_arg_t dsda;
 508         int error;
 509         nvpair_t *pair;
 510
 511         pair = nvlist_next_nvpair(snaps, NULL);
 512         if (pair == NULL)
 513                 return (0);
 514
 515         dsda.dsda_snaps = snaps;
 516         dsda.dsda_successful_snaps = fnvlist_alloc();
 517         dsda.dsda_defer = defer;
 518         dsda.dsda_errlist = errlist;
 519
 520         error = dsl_sync_task(nvpair_name(pair),
 521             dsl_destroy_snapshot_check, dsl_destroy_snapshot_sync,
 522             &dsda, 0, ZFS_SPACE_CHECK_NONE);
 523         fnvlist_free(dsda.dsda_successful_snaps);
 524
 525         return (error);
 526 }
 527
 528 int
 529 dsl_destroy_snapshot(const char *name, boolean_t defer)
 530 {
 531         int error;
 532         nvlist_t *nvl = fnvlist_alloc();
 533         nvlist_t *errlist = fnvlist_alloc();
 534
 535         fnvlist_add_boolean(nvl, name);
 536         error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
 537         fnvlist_free(errlist);
 538         fnvlist_free(nvl);
 539         return (error);
 540 }
 541
 542 struct killarg {
 543         dsl_dataset_t *ds;
 544         dmu_tx_t *tx;
 545 };
 546
 547 /* ARGSUSED */
 548 static int
 549 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 550     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
 551 {
 552         struct killarg *ka = arg;
 553         dmu_tx_t *tx = ka->tx;
 554
 555         if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
 556                 return (0);
 557
 558         if (zb->zb_level == ZB_ZIL_LEVEL) {
 559                 ASSERT(zilog != NULL);
 560                 /*
 561                  * It's a block in the intent log.  It has no
 562                  * accounting, so just free it.
 563                  */
 564                 dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
 565         } else {
 566                 ASSERT(zilog == NULL);
 567                 ASSERT3U(bp->blk_birth, >,
 568                     dsl_dataset_phys(ka->ds)->ds_prev_snap_txg);
 569                 (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
 570         }
 571
 572         return (0);
 573 }
 574
 575 static void
 576 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 577 {
 578         struct killarg ka;
 579
 580         /*
 581          * Free everything that we point to (that's born after
 582          * the previous snapshot, if we are a clone)
 583          *
 584          * NB: this should be very quick, because we already
 585          * freed all the objects in open context.
 586          */
 587         ka.ds = ds;
 588         ka.tx = tx;
 589         VERIFY0(traverse_dataset(ds,
 590             dsl_dataset_phys(ds)->ds_prev_snap_txg, TRAVERSE_POST,
 591             kill_blkptr, &ka));
 592         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 593             dsl_dataset_phys(ds)->ds_unique_bytes == 0);
 594 }
 595
 596 typedef struct dsl_destroy_head_arg {
 597         const char *ddha_name;
 598 } dsl_destroy_head_arg_t;
 599
 600 int
 601 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
 602 {
 603         int error;
 604         uint64_t count;
 605         objset_t *mos;
 606
 607         ASSERT(!dsl_dataset_is_snapshot(ds));
 608         if (dsl_dataset_is_snapshot(ds))
 609                 return (SET_ERROR(EINVAL));
 610
 611         if (refcount_count(&ds->ds_longholds) != expected_holds)
 612                 return (SET_ERROR(EBUSY));
 613
 614         mos = ds->ds_dir->dd_pool->dp_meta_objset;
 615
 616         /*
 617          * Can't delete a head dataset if there are snapshots of it.
 618          * (Except if the only snapshots are from the branch we cloned
 619          * from.)
 620          */
 621         if (ds->ds_prev != NULL &&
 622             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj == ds->ds_object)
 623                 return (SET_ERROR(EBUSY));
 624
 625         /*
 626          * Can't delete if there are children of this fs.
 627          */
 628         error = zap_count(mos,
 629             dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, &count);
 630         if (error != 0)
 631                 return (error);
 632         if (count != 0)
 633                 return (SET_ERROR(EEXIST));
 634
 635         if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 636             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 637             ds->ds_prev->ds_userrefs == 0) {
 638                 /* We need to remove the origin snapshot as well. */
 639                 if (!refcount_is_zero(&ds->ds_prev->ds_longholds))
 640                         return (SET_ERROR(EBUSY));
 641         }
 642         return (0);
 643 }
 644
 645 static int
 646 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
 647 {
 648         dsl_destroy_head_arg_t *ddha = arg;
 649         dsl_pool_t *dp = dmu_tx_pool(tx);
 650         dsl_dataset_t *ds;
 651         int error;
 652
 653         error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
 654         if (error != 0)
 655                 return (error);
 656
 657         error = dsl_destroy_head_check_impl(ds, 0);
 658         dsl_dataset_rele(ds, FTAG);
 659         return (error);
 660 }
 661
 662 static void
 663 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
 664 {
 665         dsl_dir_t *dd;
 666         dsl_pool_t *dp = dmu_tx_pool(tx);
 667         objset_t *mos = dp->dp_meta_objset;
 668         dd_used_t t;
 669
 670         ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
 671
 672         VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
 673
 674         ASSERT0(dsl_dir_phys(dd)->dd_head_dataset_obj);
 675
 676         /*
 677          * Decrement the filesystem count for all parent filesystems.
 678          *
 679          * When we receive an incremental stream into a filesystem that already
 680          * exists, a temporary clone is created.  We never count this temporary
 681          * clone, whose name begins with a '%'.
 682          */
 683         if (dd->dd_myname[0] != '%' && dd->dd_parent != NULL)
 684                 dsl_fs_ss_count_adjust(dd->dd_parent, -1,
 685                     DD_FIELD_FILESYSTEM_COUNT, tx);
 686
 687         /*
 688          * Remove our reservation. The impl() routine avoids setting the
 689          * actual property, which would require the (already destroyed) ds.
 690          */
 691         dsl_dir_set_reservation_sync_impl(dd, 0, tx);
 692
 693         ASSERT0(dsl_dir_phys(dd)->dd_used_bytes);
 694         ASSERT0(dsl_dir_phys(dd)->dd_reserved);
 695         for (t = 0; t < DD_USED_NUM; t++)
 696                 ASSERT0(dsl_dir_phys(dd)->dd_used_breakdown[t]);
 697
 698         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_child_dir_zapobj, tx));
 699         VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_props_zapobj, tx));
 700         VERIFY0(dsl_deleg_destroy(mos, dsl_dir_phys(dd)->dd_deleg_zapobj, tx));
 701         VERIFY0(zap_remove(mos,
 702             dsl_dir_phys(dd->dd_parent)->dd_child_dir_zapobj,
 703             dd->dd_myname, tx));
 704
 705         dsl_dir_rele(dd, FTAG);
 706         dmu_object_free_zapified(mos, ddobj, tx);
 707 }
 708
 709 void
 710 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
 711 {
 712         dsl_pool_t *dp = dmu_tx_pool(tx);
 713         objset_t *mos = dp->dp_meta_objset;
 714         uint64_t obj, ddobj, prevobj = 0;
 715         boolean_t rmorigin;
 716
 717         ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
 718         ASSERT(ds->ds_prev == NULL ||
 719             dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj != ds->ds_object);
 720         ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
 721         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 722
 723         /* We need to log before removing it from the namespace. */
 724         spa_history_log_internal_ds(ds, "destroy", tx, "");
 725
 726         rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
 727             DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 728             dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
 729             ds->ds_prev->ds_userrefs == 0);
 730
 731         /* Remove our reservation. */
 732         if (ds->ds_reserved != 0) {
 733                 dsl_dataset_set_refreservation_sync_impl(ds,
 734                     (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
 735                     0, tx);
 736                 ASSERT0(ds->ds_reserved);
 737         }
 738
 739         if (ds->ds_large_blocks)
 740                 spa_feature_decr(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS, tx);
 741
 742         dsl_scan_ds_destroyed(ds, tx);
 743
 744         obj = ds->ds_object;
 745
 746         if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
 747                 /* This is a clone */
 748                 ASSERT(ds->ds_prev != NULL);
 749                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj, !=,
 750                     obj);
 751                 ASSERT0(dsl_dataset_phys(ds)->ds_next_snap_obj);
 752
 753                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 754                 if (dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj != 0) {
 755                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
 756                             obj, tx);
 757                 }
 758
 759                 ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_num_children, >, 1);
 760                 dsl_dataset_phys(ds->ds_prev)->ds_num_children--;
 761         }
 762
 763         /*
 764          * Destroy the deadlist.  Unless it's a clone, the
 765          * deadlist should be empty.  (If it's a clone, it's
 766          * safe to ignore the deadlist contents.)
 767          */
 768         dsl_deadlist_close(&ds->ds_deadlist);
 769         dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
 770         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 771         dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
 772
 773         objset_t *os;
 774         VERIFY0(dmu_objset_from_ds(ds, &os));
 775
 776         if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
 777                 old_synchronous_dataset_destroy(ds, tx);
 778         } else {
 779                 /*
 780                  * Move the bptree into the pool's list of trees to
 781                  * clean up and update space accounting information.
 782                  */
 783                 uint64_t used, comp, uncomp;
 784
 785                 zil_destroy_sync(dmu_objset_zil(os), tx);
 786
 787                 if (!spa_feature_is_active(dp->dp_spa,
 788                     SPA_FEATURE_ASYNC_DESTROY)) {
 789                         dsl_scan_t *scn = dp->dp_scan;
 790                         spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
 791                             tx);
 792                         dp->dp_bptree_obj = bptree_alloc(mos, tx);
 793                         VERIFY0(zap_add(mos,
 794                             DMU_POOL_DIRECTORY_OBJECT,
 795                             DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
 796                             &dp->dp_bptree_obj, tx));
 797                         ASSERT(!scn->scn_async_destroying);
 798                         scn->scn_async_destroying = B_TRUE;
 799                 }
 800
 801                 used = dsl_dir_phys(ds->ds_dir)->dd_used_bytes;
 802                 comp = dsl_dir_phys(ds->ds_dir)->dd_compressed_bytes;
 803                 uncomp = dsl_dir_phys(ds->ds_dir)->dd_uncompressed_bytes;
 804
 805                 ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 806                     dsl_dataset_phys(ds)->ds_unique_bytes == used);
 807
 808                 bptree_add(mos, dp->dp_bptree_obj,
 809                     &dsl_dataset_phys(ds)->ds_bp,
 810                     dsl_dataset_phys(ds)->ds_prev_snap_txg,
 811                     used, comp, uncomp, tx);
 812                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 813                     -used, -comp, -uncomp, tx);
 814                 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
 815                     used, comp, uncomp, tx);
 816         }
 817
 818         if (ds->ds_prev != NULL) {
 819                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 820                         VERIFY0(zap_remove_int(mos,
 821                             dsl_dir_phys(ds->ds_prev->ds_dir)->dd_clones,
 822                             ds->ds_object, tx));
 823                 }
 824                 prevobj = ds->ds_prev->ds_object;
 825                 dsl_dataset_rele(ds->ds_prev, ds);
 826                 ds->ds_prev = NULL;
 827         }
 828
 829         /*
 830          * This must be done after the dsl_traverse(), because it will
 831          * re-open the objset.
 832          */
 833         if (ds->ds_objset) {
 834                 dmu_objset_evict(ds->ds_objset);
 835                 ds->ds_objset = NULL;
 836         }
 837
 838         /* Erase the link in the dir */
 839         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 840         dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj = 0;
 841         ddobj = ds->ds_dir->dd_object;
 842         ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0);
 843         VERIFY0(zap_destroy(mos,
 844             dsl_dataset_phys(ds)->ds_snapnames_zapobj, tx));
 845
 846         if (ds->ds_bookmarks != 0) {
 847                 VERIFY0(zap_destroy(mos, ds->ds_bookmarks, tx));
 848                 spa_feature_decr(dp->dp_spa, SPA_FEATURE_BOOKMARKS, tx);
 849         }
 850
 851         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 852
 853         ASSERT0(dsl_dataset_phys(ds)->ds_next_clones_obj);
 854         ASSERT0(dsl_dataset_phys(ds)->ds_props_obj);
 855         ASSERT0(dsl_dataset_phys(ds)->ds_userrefs_obj);
 856         dsl_dir_rele(ds->ds_dir, ds);
 857         ds->ds_dir = NULL;
 858         dmu_object_free_zapified(mos, obj, tx);
 859
 860         dsl_dir_destroy_sync(ddobj, tx);
 861
 862         if (rmorigin) {
 863                 dsl_dataset_t *prev;
 864                 VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
 865                 dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
 866                 dsl_dataset_rele(prev, FTAG);
 867         }
 868 }
 869
 870 static void
 871 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
 872 {
 873         dsl_destroy_head_arg_t *ddha = arg;
 874         dsl_pool_t *dp = dmu_tx_pool(tx);
 875         dsl_dataset_t *ds;
 876
 877         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 878         dsl_destroy_head_sync_impl(ds, tx);
 879         dsl_dataset_rele(ds, FTAG);
 880 }
 881
 882 static void
 883 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
 884 {
 885         dsl_destroy_head_arg_t *ddha = arg;
 886         dsl_pool_t *dp = dmu_tx_pool(tx);
 887         dsl_dataset_t *ds;
 888
 889         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 890
 891         /* Mark it as inconsistent on-disk, in case we crash */
 892         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 893         dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
 894
 895         spa_history_log_internal_ds(ds, "destroy begin", tx, "");
 896         dsl_dataset_rele(ds, FTAG);
 897 }
 898
 899 int
 900 dsl_destroy_head(const char *name)
 901 {
 902         dsl_destroy_head_arg_t ddha;
 903         int error;
 904         spa_t *spa;
 905         boolean_t isenabled;
 906
 907 #ifdef _KERNEL
 908         zfs_destroy_unmount_origin(name);
 909 #endif
 910
 911         error = spa_open(name, &spa, FTAG);
 912         if (error != 0)
 913                 return (error);
 914         isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
 915         spa_close(spa, FTAG);
 916
 917         ddha.ddha_name = name;
 918
 919         if (!isenabled) {
 920                 objset_t *os;
 921
 922                 error = dsl_sync_task(name, dsl_destroy_head_check,
 923                     dsl_destroy_head_begin_sync, &ddha,
 924                     0, ZFS_SPACE_CHECK_NONE);
 925                 if (error != 0)
 926                         return (error);
 927
 928                 /*
 929                  * Head deletion is processed in one txg on old pools;
 930                  * remove the objects from open context so that the txg sync
 931                  * is not too long.
 932                  */
 933                 error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, FTAG, &os);
 934                 if (error == 0) {
 935                         uint64_t prev_snap_txg =
 936                             dsl_dataset_phys(dmu_objset_ds(os))->
 937                             ds_prev_snap_txg;
 938                         for (uint64_t obj = 0; error == 0;
 939                             error = dmu_object_next(os, &obj, FALSE,
 940                             prev_snap_txg))
 941                                 (void) dmu_free_long_object(os, obj);
 942                         /* sync out all frees */
 943                         txg_wait_synced(dmu_objset_pool(os), 0);
 944                         dmu_objset_disown(os, FTAG);
 945                 }
 946         }
 947
 948         return (dsl_sync_task(name, dsl_destroy_head_check,
 949             dsl_destroy_head_sync, &ddha, 0, ZFS_SPACE_CHECK_NONE));
 950 }
 951
 952 /*
 953  * Note, this function is used as the callback for dmu_objset_find().  We
 954  * always return 0 so that we will continue to find and process
 955  * inconsistent datasets, even if we encounter an error trying to
 956  * process one of them.
 957  */
 958 /* ARGSUSED */
 959 int
 960 dsl_destroy_inconsistent(const char *dsname, void *arg)
 961 {
 962         objset_t *os;
 963
 964         if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
 965                 boolean_t inconsistent = DS_IS_INCONSISTENT(dmu_objset_ds(os));
 966                 dmu_objset_rele(os, FTAG);
 967                 if (inconsistent)
 968                         (void) dsl_destroy_head(dsname);
 969         }
 970         return (0);
 971 }