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