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) 2013 by Delphix. All rights reserved.
  24  * Copyright (c) 2013 Steven Hartland. All rights reserved.
  25  */
  26
  27 #include <sys/zfs_context.h>
  28 #include <sys/dsl_userhold.h>
  29 #include <sys/dsl_dataset.h>
  30 #include <sys/dsl_synctask.h>
  31 #include <sys/dmu_tx.h>
  32 #include <sys/dsl_pool.h>
  33 #include <sys/dsl_dir.h>
  34 #include <sys/dmu_traverse.h>
  35 #include <sys/dsl_scan.h>
  36 #include <sys/dmu_objset.h>
  37 #include <sys/zap.h>
  38 #include <sys/zfeature.h>
  39 #include <sys/zfs_ioctl.h>
  40 #include <sys/dsl_deleg.h>
  41 #include <sys/dmu_impl.h>
  42
  43 typedef struct dmu_snapshots_destroy_arg {
  44         nvlist_t *dsda_snaps;
  45         nvlist_t *dsda_successful_snaps;
  46         boolean_t dsda_defer;
  47         nvlist_t *dsda_errlist;
  48 } dmu_snapshots_destroy_arg_t;
  49
  50 int
  51 dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
  52 {
  53         if (!dsl_dataset_is_snapshot(ds))
  54                 return (SET_ERROR(EINVAL));
  55
  56         if (dsl_dataset_long_held(ds))
  57                 return (SET_ERROR(EBUSY));
  58
  59         /*
  60          * Only allow deferred destroy on pools that support it.
  61          * NOTE: deferred destroy is only supported on snapshots.
  62          */
  63         if (defer) {
  64                 if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
  65                     SPA_VERSION_USERREFS)
  66                         return (SET_ERROR(ENOTSUP));
  67                 return (0);
  68         }
  69
  70         /*
  71          * If this snapshot has an elevated user reference count,
  72          * we can't destroy it yet.
  73          */
  74         if (ds->ds_userrefs > 0)
  75                 return (SET_ERROR(EBUSY));
  76
  77         /*
  78          * Can't delete a branch point.
  79          */
  80         if (ds->ds_phys->ds_num_children > 1)
  81                 return (SET_ERROR(EEXIST));
  82
  83         return (0);
  84 }
  85
  86 static int
  87 dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
  88 {
  89         dmu_snapshots_destroy_arg_t *dsda = arg;
  90         dsl_pool_t *dp = dmu_tx_pool(tx);
  91         nvpair_t *pair;
  92         int error = 0;
  93
  94         if (!dmu_tx_is_syncing(tx))
  95                 return (0);
  96
  97         for (pair = nvlist_next_nvpair(dsda->dsda_snaps, NULL);
  98             pair != NULL; pair = nvlist_next_nvpair(dsda->dsda_snaps, pair)) {
  99                 dsl_dataset_t *ds;
 100
 101                 error = dsl_dataset_hold(dp, nvpair_name(pair),
 102                     FTAG, &ds);
 103
 104                 /*
 105                  * If the snapshot does not exist, silently ignore it
 106                  * (it's "already destroyed").
 107                  */
 108                 if (error == ENOENT)
 109                         continue;
 110
 111                 if (error == 0) {
 112                         error = dsl_destroy_snapshot_check_impl(ds,
 113                             dsda->dsda_defer);
 114                         dsl_dataset_rele(ds, FTAG);
 115                 }
 116
 117                 if (error == 0) {
 118                         fnvlist_add_boolean(dsda->dsda_successful_snaps,
 119                             nvpair_name(pair));
 120                 } else {
 121                         fnvlist_add_int32(dsda->dsda_errlist,
 122                             nvpair_name(pair), error);
 123                 }
 124         }
 125
 126         pair = nvlist_next_nvpair(dsda->dsda_errlist, NULL);
 127         if (pair != NULL)
 128                 return (fnvpair_value_int32(pair));
 129
 130         return (0);
 131 }
 132
 133 struct process_old_arg {
 134         dsl_dataset_t *ds;
 135         dsl_dataset_t *ds_prev;
 136         boolean_t after_branch_point;
 137         zio_t *pio;
 138         uint64_t used, comp, uncomp;
 139 };
 140
 141 static int
 142 process_old_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
 143 {
 144         struct process_old_arg *poa = arg;
 145         dsl_pool_t *dp = poa->ds->ds_dir->dd_pool;
 146
 147         if (bp->blk_birth <= poa->ds->ds_phys->ds_prev_snap_txg) {
 148                 dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, tx);
 149                 if (poa->ds_prev && !poa->after_branch_point &&
 150                     bp->blk_birth >
 151                     poa->ds_prev->ds_phys->ds_prev_snap_txg) {
 152                         poa->ds_prev->ds_phys->ds_unique_bytes +=
 153                             bp_get_dsize_sync(dp->dp_spa, bp);
 154                 }
 155         } else {
 156                 poa->used += bp_get_dsize_sync(dp->dp_spa, bp);
 157                 poa->comp += BP_GET_PSIZE(bp);
 158                 poa->uncomp += BP_GET_UCSIZE(bp);
 159                 dsl_free_sync(poa->pio, dp, tx->tx_txg, bp);
 160         }
 161         return (0);
 162 }
 163
 164 static void
 165 process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev,
 166     dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx)
 167 {
 168         struct process_old_arg poa = { 0 };
 169         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 170         objset_t *mos = dp->dp_meta_objset;
 171         uint64_t deadlist_obj;
 172
 173         ASSERT(ds->ds_deadlist.dl_oldfmt);
 174         ASSERT(ds_next->ds_deadlist.dl_oldfmt);
 175
 176         poa.ds = ds;
 177         poa.ds_prev = ds_prev;
 178         poa.after_branch_point = after_branch_point;
 179         poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
 180         VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
 181             process_old_cb, &poa, tx));
 182         VERIFY0(zio_wait(poa.pio));
 183         ASSERT3U(poa.used, ==, ds->ds_phys->ds_unique_bytes);
 184
 185         /* change snapused */
 186         dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 187             -poa.used, -poa.comp, -poa.uncomp, tx);
 188
 189         /* swap next's deadlist to our deadlist */
 190         dsl_deadlist_close(&ds->ds_deadlist);
 191         dsl_deadlist_close(&ds_next->ds_deadlist);
 192         deadlist_obj = ds->ds_phys->ds_deadlist_obj;
 193         ds->ds_phys->ds_deadlist_obj = ds_next->ds_phys->ds_deadlist_obj;
 194         ds_next->ds_phys->ds_deadlist_obj = deadlist_obj;
 195         dsl_deadlist_open(&ds->ds_deadlist, mos, ds->ds_phys->ds_deadlist_obj);
 196         dsl_deadlist_open(&ds_next->ds_deadlist, mos,
 197             ds_next->ds_phys->ds_deadlist_obj);
 198 }
 199
 200 static void
 201 dsl_dataset_remove_clones_key(dsl_dataset_t *ds, uint64_t mintxg, dmu_tx_t *tx)
 202 {
 203         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 204         zap_cursor_t zc;
 205         zap_attribute_t za;
 206
 207         /*
 208          * If it is the old version, dd_clones doesn't exist so we can't
 209          * find the clones, but dsl_deadlist_remove_key() is a no-op so it
 210          * doesn't matter.
 211          */
 212         if (ds->ds_dir->dd_phys->dd_clones == 0)
 213                 return;
 214
 215         for (zap_cursor_init(&zc, mos, ds->ds_dir->dd_phys->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(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                         dsl_dataset_remove_clones_key(clone, mintxg, tx);
 226                 }
 227                 dsl_dataset_rele(clone, FTAG);
 228         }
 229         zap_cursor_fini(&zc);
 230 }
 231
 232 void
 233 dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
 234 {
 235         int err;
 236         int after_branch_point = FALSE;
 237         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 238         objset_t *mos = dp->dp_meta_objset;
 239         dsl_dataset_t *ds_prev = NULL;
 240         uint64_t obj;
 241
 242         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 243         ASSERT3U(ds->ds_phys->ds_bp.blk_birth, <=, tx->tx_txg);
 244         ASSERT(refcount_is_zero(&ds->ds_longholds));
 245
 246         if (defer &&
 247             (ds->ds_userrefs > 0 || ds->ds_phys->ds_num_children > 1)) {
 248                 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
 249                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 250                 ds->ds_phys->ds_flags |= DS_FLAG_DEFER_DESTROY;
 251                 spa_history_log_internal_ds(ds, "defer_destroy", tx, "");
 252                 return;
 253         }
 254
 255         ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
 256
 257         /* We need to log before removing it from the namespace. */
 258         spa_history_log_internal_ds(ds, "destroy", tx, "");
 259
 260         dsl_scan_ds_destroyed(ds, tx);
 261
 262         obj = ds->ds_object;
 263
 264         if (ds->ds_phys->ds_prev_snap_obj != 0) {
 265                 ASSERT3P(ds->ds_prev, ==, NULL);
 266                 VERIFY0(dsl_dataset_hold_obj(dp,
 267                     ds->ds_phys->ds_prev_snap_obj, FTAG, &ds_prev));
 268                 after_branch_point =
 269                     (ds_prev->ds_phys->ds_next_snap_obj != obj);
 270
 271                 dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
 272                 if (after_branch_point &&
 273                     ds_prev->ds_phys->ds_next_clones_obj != 0) {
 274                         dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
 275                         if (ds->ds_phys->ds_next_snap_obj != 0) {
 276                                 VERIFY0(zap_add_int(mos,
 277                                     ds_prev->ds_phys->ds_next_clones_obj,
 278                                     ds->ds_phys->ds_next_snap_obj, tx));
 279                         }
 280                 }
 281                 if (!after_branch_point) {
 282                         ds_prev->ds_phys->ds_next_snap_obj =
 283                             ds->ds_phys->ds_next_snap_obj;
 284                 }
 285         }
 286
 287         dsl_dataset_t *ds_next;
 288         uint64_t old_unique;
 289         uint64_t used = 0, comp = 0, uncomp = 0;
 290
 291         VERIFY0(dsl_dataset_hold_obj(dp,
 292             ds->ds_phys->ds_next_snap_obj, FTAG, &ds_next));
 293         ASSERT3U(ds_next->ds_phys->ds_prev_snap_obj, ==, obj);
 294
 295         old_unique = ds_next->ds_phys->ds_unique_bytes;
 296
 297         dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
 298         ds_next->ds_phys->ds_prev_snap_obj =
 299             ds->ds_phys->ds_prev_snap_obj;
 300         ds_next->ds_phys->ds_prev_snap_txg =
 301             ds->ds_phys->ds_prev_snap_txg;
 302         ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==,
 303             ds_prev ? ds_prev->ds_phys->ds_creation_txg : 0);
 304
 305         if (ds_next->ds_deadlist.dl_oldfmt) {
 306                 process_old_deadlist(ds, ds_prev, ds_next,
 307                     after_branch_point, tx);
 308         } else {
 309                 /* Adjust prev's unique space. */
 310                 if (ds_prev && !after_branch_point) {
 311                         dsl_deadlist_space_range(&ds_next->ds_deadlist,
 312                             ds_prev->ds_phys->ds_prev_snap_txg,
 313                             ds->ds_phys->ds_prev_snap_txg,
 314                             &used, &comp, &uncomp);
 315                         ds_prev->ds_phys->ds_unique_bytes += used;
 316                 }
 317
 318                 /* Adjust snapused. */
 319                 dsl_deadlist_space_range(&ds_next->ds_deadlist,
 320                     ds->ds_phys->ds_prev_snap_txg, UINT64_MAX,
 321                     &used, &comp, &uncomp);
 322                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
 323                     -used, -comp, -uncomp, tx);
 324
 325                 /* Move blocks to be freed to pool's free list. */
 326                 dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
 327                     &dp->dp_free_bpobj, ds->ds_phys->ds_prev_snap_txg,
 328                     tx);
 329                 dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
 330                     DD_USED_HEAD, used, comp, uncomp, tx);
 331
 332                 /* Merge our deadlist into next's and free it. */
 333                 dsl_deadlist_merge(&ds_next->ds_deadlist,
 334                     ds->ds_phys->ds_deadlist_obj, tx);
 335         }
 336         dsl_deadlist_close(&ds->ds_deadlist);
 337         dsl_deadlist_free(mos, ds->ds_phys->ds_deadlist_obj, tx);
 338         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 339         ds->ds_phys->ds_deadlist_obj = 0;
 340
 341         /* Collapse range in clone heads */
 342         dsl_dataset_remove_clones_key(ds,
 343             ds->ds_phys->ds_creation_txg, tx);
 344
 345         if (dsl_dataset_is_snapshot(ds_next)) {
 346                 dsl_dataset_t *ds_nextnext;
 347
 348                 /*
 349                  * Update next's unique to include blocks which
 350                  * were previously shared by only this snapshot
 351                  * and it.  Those blocks will be born after the
 352                  * prev snap and before this snap, and will have
 353                  * died after the next snap and before the one
 354                  * after that (ie. be on the snap after next's
 355                  * deadlist).
 356                  */
 357                 VERIFY0(dsl_dataset_hold_obj(dp,
 358                     ds_next->ds_phys->ds_next_snap_obj, FTAG, &ds_nextnext));
 359                 dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
 360                     ds->ds_phys->ds_prev_snap_txg,
 361                     ds->ds_phys->ds_creation_txg,
 362                     &used, &comp, &uncomp);
 363                 ds_next->ds_phys->ds_unique_bytes += used;
 364                 dsl_dataset_rele(ds_nextnext, FTAG);
 365                 ASSERT3P(ds_next->ds_prev, ==, NULL);
 366
 367                 /* Collapse range in this head. */
 368                 dsl_dataset_t *hds;
 369                 VERIFY0(dsl_dataset_hold_obj(dp,
 370                     ds->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &hds));
 371                 dsl_deadlist_remove_key(&hds->ds_deadlist,
 372                     ds->ds_phys->ds_creation_txg, tx);
 373                 dsl_dataset_rele(hds, FTAG);
 374
 375         } else {
 376                 ASSERT3P(ds_next->ds_prev, ==, ds);
 377                 dsl_dataset_rele(ds_next->ds_prev, ds_next);
 378                 ds_next->ds_prev = NULL;
 379                 if (ds_prev) {
 380                         VERIFY0(dsl_dataset_hold_obj(dp,
 381                             ds->ds_phys->ds_prev_snap_obj,
 382                             ds_next, &ds_next->ds_prev));
 383                 }
 384
 385                 dsl_dataset_recalc_head_uniq(ds_next);
 386
 387                 /*
 388                  * Reduce the amount of our unconsumed refreservation
 389                  * being charged to our parent by the amount of
 390                  * new unique data we have gained.
 391                  */
 392                 if (old_unique < ds_next->ds_reserved) {
 393                         int64_t mrsdelta;
 394                         uint64_t new_unique =
 395                             ds_next->ds_phys->ds_unique_bytes;
 396
 397                         ASSERT(old_unique <= new_unique);
 398                         mrsdelta = MIN(new_unique - old_unique,
 399                             ds_next->ds_reserved - old_unique);
 400                         dsl_dir_diduse_space(ds->ds_dir,
 401                             DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
 402                 }
 403         }
 404         dsl_dataset_rele(ds_next, FTAG);
 405
 406         /*
 407          * This must be done after the dsl_traverse(), because it will
 408          * re-open the objset.
 409          */
 410         if (ds->ds_objset) {
 411                 dmu_objset_evict(ds->ds_objset);
 412                 ds->ds_objset = NULL;
 413         }
 414
 415         /* remove from snapshot namespace */
 416         dsl_dataset_t *ds_head;
 417         ASSERT(ds->ds_phys->ds_snapnames_zapobj == 0);
 418         VERIFY0(dsl_dataset_hold_obj(dp,
 419             ds->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &ds_head));
 420         VERIFY0(dsl_dataset_get_snapname(ds));
 421 #ifdef ZFS_DEBUG
 422         {
 423                 uint64_t val;
 424
 425                 err = dsl_dataset_snap_lookup(ds_head,
 426                     ds->ds_snapname, &val);
 427                 ASSERT0(err);
 428                 ASSERT3U(val, ==, obj);
 429         }
 430 #endif
 431         VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx));
 432         dsl_dataset_rele(ds_head, FTAG);
 433
 434         if (ds_prev != NULL)
 435                 dsl_dataset_rele(ds_prev, FTAG);
 436
 437         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 438
 439         if (ds->ds_phys->ds_next_clones_obj != 0) {
 440                 uint64_t count;
 441                 ASSERT0(zap_count(mos,
 442                     ds->ds_phys->ds_next_clones_obj, &count) && count == 0);
 443                 VERIFY0(dmu_object_free(mos,
 444                     ds->ds_phys->ds_next_clones_obj, tx));
 445         }
 446         if (ds->ds_phys->ds_props_obj != 0)
 447                 VERIFY0(zap_destroy(mos, ds->ds_phys->ds_props_obj, tx));
 448         if (ds->ds_phys->ds_userrefs_obj != 0)
 449                 VERIFY0(zap_destroy(mos, ds->ds_phys->ds_userrefs_obj, tx));
 450         dsl_dir_rele(ds->ds_dir, ds);
 451         ds->ds_dir = NULL;
 452         dmu_object_free_zapified(mos, obj, tx);
 453 }
 454
 455 static void
 456 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
 457 {
 458         dmu_snapshots_destroy_arg_t *dsda = arg;
 459         dsl_pool_t *dp = dmu_tx_pool(tx);
 460         nvpair_t *pair;
 461
 462         for (pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, NULL);
 463             pair != NULL;
 464             pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, pair)) {
 465                 dsl_dataset_t *ds;
 466
 467                 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
 468
 469                 dsl_destroy_snapshot_sync_impl(ds, dsda->dsda_defer, tx);
 470                 dsl_dataset_rele(ds, FTAG);
 471         }
 472 }
 473
 474 /*
 475  * The semantics of this function are described in the comment above
 476  * lzc_destroy_snaps().  To summarize:
 477  *
 478  * The snapshots must all be in the same pool.
 479  *
 480  * Snapshots that don't exist will be silently ignored (considered to be
 481  * "already deleted").
 482  *
 483  * On success, all snaps will be destroyed and this will return 0.
 484  * On failure, no snaps will be destroyed, the errlist will be filled in,
 485  * and this will return an errno.
 486  */
 487 int
 488 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
 489     nvlist_t *errlist)
 490 {
 491         dmu_snapshots_destroy_arg_t dsda;
 492         int error;
 493         nvpair_t *pair;
 494
 495         pair = nvlist_next_nvpair(snaps, NULL);
 496         if (pair == NULL)
 497                 return (0);
 498
 499         dsda.dsda_snaps = snaps;
 500         dsda.dsda_successful_snaps = fnvlist_alloc();
 501         dsda.dsda_defer = defer;
 502         dsda.dsda_errlist = errlist;
 503
 504         error = dsl_sync_task(nvpair_name(pair),
 505             dsl_destroy_snapshot_check, dsl_destroy_snapshot_sync,
 506             &dsda, 0);
 507         fnvlist_free(dsda.dsda_successful_snaps);
 508
 509         return (error);
 510 }
 511
 512 int
 513 dsl_destroy_snapshot(const char *name, boolean_t defer)
 514 {
 515         int error;
 516         nvlist_t *nvl = fnvlist_alloc();
 517         nvlist_t *errlist = fnvlist_alloc();
 518
 519         fnvlist_add_boolean(nvl, name);
 520         error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
 521         fnvlist_free(errlist);
 522         fnvlist_free(nvl);
 523         return (error);
 524 }
 525
 526 struct killarg {
 527         dsl_dataset_t *ds;
 528         dmu_tx_t *tx;
 529 };
 530
 531 /* ARGSUSED */
 532 static int
 533 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
 534     const zbookmark_t *zb, const dnode_phys_t *dnp, void *arg)
 535 {
 536         struct killarg *ka = arg;
 537         dmu_tx_t *tx = ka->tx;
 538
 539         if (bp == NULL)
 540                 return (0);
 541
 542         if (zb->zb_level == ZB_ZIL_LEVEL) {
 543                 ASSERT(zilog != NULL);
 544                 /*
 545                  * It's a block in the intent log.  It has no
 546                  * accounting, so just free it.
 547                  */
 548                 dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
 549         } else {
 550                 ASSERT(zilog == NULL);
 551                 ASSERT3U(bp->blk_birth, >, ka->ds->ds_phys->ds_prev_snap_txg);
 552                 (void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
 553         }
 554
 555         return (0);
 556 }
 557
 558 static void
 559 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
 560 {
 561         struct killarg ka;
 562
 563         /*
 564          * Free everything that we point to (that's born after
 565          * the previous snapshot, if we are a clone)
 566          *
 567          * NB: this should be very quick, because we already
 568          * freed all the objects in open context.
 569          */
 570         ka.ds = ds;
 571         ka.tx = tx;
 572         VERIFY0(traverse_dataset(ds,
 573             ds->ds_phys->ds_prev_snap_txg, TRAVERSE_POST,
 574             kill_blkptr, &ka));
 575         ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) || ds->ds_phys->ds_unique_bytes == 0);
 576 }
 577
 578 typedef struct dsl_destroy_head_arg {
 579         const char *ddha_name;
 580 } dsl_destroy_head_arg_t;
 581
 582 int
 583 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
 584 {
 585         int error;
 586         uint64_t count;
 587         objset_t *mos;
 588
 589         if (dsl_dataset_is_snapshot(ds))
 590                 return (SET_ERROR(EINVAL));
 591
 592         if (refcount_count(&ds->ds_longholds) != expected_holds)
 593                 return (SET_ERROR(EBUSY));
 594
 595         mos = ds->ds_dir->dd_pool->dp_meta_objset;
 596
 597         /*
 598          * Can't delete a head dataset if there are snapshots of it.
 599          * (Except if the only snapshots are from the branch we cloned
 600          * from.)
 601          */
 602         if (ds->ds_prev != NULL &&
 603             ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object)
 604                 return (SET_ERROR(EBUSY));
 605
 606         /*
 607          * Can't delete if there are children of this fs.
 608          */
 609         error = zap_count(mos,
 610             ds->ds_dir->dd_phys->dd_child_dir_zapobj, &count);
 611         if (error != 0)
 612                 return (error);
 613         if (count != 0)
 614                 return (SET_ERROR(EEXIST));
 615
 616         if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 617             ds->ds_prev->ds_phys->ds_num_children == 2 &&
 618             ds->ds_prev->ds_userrefs == 0) {
 619                 /* We need to remove the origin snapshot as well. */
 620                 if (!refcount_is_zero(&ds->ds_prev->ds_longholds))
 621                         return (SET_ERROR(EBUSY));
 622         }
 623         return (0);
 624 }
 625
 626 static int
 627 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
 628 {
 629         dsl_destroy_head_arg_t *ddha = arg;
 630         dsl_pool_t *dp = dmu_tx_pool(tx);
 631         dsl_dataset_t *ds;
 632         int error;
 633
 634         error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
 635         if (error != 0)
 636                 return (error);
 637
 638         error = dsl_destroy_head_check_impl(ds, 0);
 639         dsl_dataset_rele(ds, FTAG);
 640         return (error);
 641 }
 642
 643 static void
 644 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
 645 {
 646         dsl_dir_t *dd;
 647         dsl_pool_t *dp = dmu_tx_pool(tx);
 648         objset_t *mos = dp->dp_meta_objset;
 649         dd_used_t t;
 650
 651         ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
 652
 653         VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
 654
 655         ASSERT0(dd->dd_phys->dd_head_dataset_obj);
 656
 657         /*
 658          * Remove our reservation. The impl() routine avoids setting the
 659          * actual property, which would require the (already destroyed) ds.
 660          */
 661         dsl_dir_set_reservation_sync_impl(dd, 0, tx);
 662
 663         ASSERT0(dd->dd_phys->dd_used_bytes);
 664         ASSERT0(dd->dd_phys->dd_reserved);
 665         for (t = 0; t < DD_USED_NUM; t++)
 666                 ASSERT0(dd->dd_phys->dd_used_breakdown[t]);
 667
 668         VERIFY0(zap_destroy(mos, dd->dd_phys->dd_child_dir_zapobj, tx));
 669         VERIFY0(zap_destroy(mos, dd->dd_phys->dd_props_zapobj, tx));
 670         VERIFY0(dsl_deleg_destroy(mos, dd->dd_phys->dd_deleg_zapobj, tx));
 671         VERIFY0(zap_remove(mos,
 672             dd->dd_parent->dd_phys->dd_child_dir_zapobj, dd->dd_myname, tx));
 673
 674         dsl_dir_rele(dd, FTAG);
 675         dmu_object_free_zapified(mos, ddobj, tx);
 676 }
 677
 678 void
 679 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
 680 {
 681         dsl_pool_t *dp = dmu_tx_pool(tx);
 682         objset_t *mos = dp->dp_meta_objset;
 683         uint64_t obj, ddobj, prevobj = 0;
 684         boolean_t rmorigin;
 685
 686         ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
 687         ASSERT(ds->ds_prev == NULL ||
 688             ds->ds_prev->ds_phys->ds_next_snap_obj != ds->ds_object);
 689         ASSERT3U(ds->ds_phys->ds_bp.blk_birth, <=, tx->tx_txg);
 690         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
 691
 692         /* We need to log before removing it from the namespace. */
 693         spa_history_log_internal_ds(ds, "destroy", tx, "");
 694
 695         rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
 696             DS_IS_DEFER_DESTROY(ds->ds_prev) &&
 697             ds->ds_prev->ds_phys->ds_num_children == 2 &&
 698             ds->ds_prev->ds_userrefs == 0);
 699
 700         /* Remove our reservation */
 701         if (ds->ds_reserved != 0) {
 702                 dsl_dataset_set_refreservation_sync_impl(ds,
 703                     (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
 704                     0, tx);
 705                 ASSERT0(ds->ds_reserved);
 706         }
 707
 708         dsl_scan_ds_destroyed(ds, tx);
 709
 710         obj = ds->ds_object;
 711
 712         if (ds->ds_phys->ds_prev_snap_obj != 0) {
 713                 /* This is a clone */
 714                 ASSERT(ds->ds_prev != NULL);
 715                 ASSERT3U(ds->ds_prev->ds_phys->ds_next_snap_obj, !=, obj);
 716                 ASSERT0(ds->ds_phys->ds_next_snap_obj);
 717
 718                 dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 719                 if (ds->ds_prev->ds_phys->ds_next_clones_obj != 0) {
 720                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
 721                             obj, tx);
 722                 }
 723
 724                 ASSERT3U(ds->ds_prev->ds_phys->ds_num_children, >, 1);
 725                 ds->ds_prev->ds_phys->ds_num_children--;
 726         }
 727
 728         /*
 729          * Destroy the deadlist.  Unless it's a clone, the
 730          * deadlist should be empty.  (If it's a clone, it's
 731          * safe to ignore the deadlist contents.)
 732          */
 733         dsl_deadlist_close(&ds->ds_deadlist);
 734         dsl_deadlist_free(mos, ds->ds_phys->ds_deadlist_obj, tx);
 735         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 736         ds->ds_phys->ds_deadlist_obj = 0;
 737
 738         objset_t *os;
 739         VERIFY0(dmu_objset_from_ds(ds, &os));
 740
 741         if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
 742                 old_synchronous_dataset_destroy(ds, tx);
 743         } else {
 744                 /*
 745                  * Move the bptree into the pool's list of trees to
 746                  * clean up and update space accounting information.
 747                  */
 748                 uint64_t used, comp, uncomp;
 749
 750                 zil_destroy_sync(dmu_objset_zil(os), tx);
 751
 752                 if (!spa_feature_is_active(dp->dp_spa,
 753                     SPA_FEATURE_ASYNC_DESTROY)) {
 754                         dsl_scan_t *scn = dp->dp_scan;
 755                         spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
 756                             tx);
 757                         dp->dp_bptree_obj = bptree_alloc(mos, tx);
 758                         VERIFY0(zap_add(mos,
 759                             DMU_POOL_DIRECTORY_OBJECT,
 760                             DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
 761                             &dp->dp_bptree_obj, tx));
 762                         ASSERT(!scn->scn_async_destroying);
 763                         scn->scn_async_destroying = B_TRUE;
 764                 }
 765
 766                 used = ds->ds_dir->dd_phys->dd_used_bytes;
 767                 comp = ds->ds_dir->dd_phys->dd_compressed_bytes;
 768                 uncomp = ds->ds_dir->dd_phys->dd_uncompressed_bytes;
 769
 770                 ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
 771                     ds->ds_phys->ds_unique_bytes == used);
 772
 773                 bptree_add(mos, dp->dp_bptree_obj,
 774                     &ds->ds_phys->ds_bp, ds->ds_phys->ds_prev_snap_txg,
 775                     used, comp, uncomp, tx);
 776                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 777                     -used, -comp, -uncomp, tx);
 778                 dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
 779                     used, comp, uncomp, tx);
 780         }
 781
 782         if (ds->ds_prev != NULL) {
 783                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 784                         VERIFY0(zap_remove_int(mos,
 785                             ds->ds_prev->ds_dir->dd_phys->dd_clones,
 786                             ds->ds_object, tx));
 787                 }
 788                 prevobj = ds->ds_prev->ds_object;
 789                 dsl_dataset_rele(ds->ds_prev, ds);
 790                 ds->ds_prev = NULL;
 791         }
 792
 793         /*
 794          * This must be done after the dsl_traverse(), because it will
 795          * re-open the objset.
 796          */
 797         if (ds->ds_objset) {
 798                 dmu_objset_evict(ds->ds_objset);
 799                 ds->ds_objset = NULL;
 800         }
 801
 802         /* Erase the link in the dir */
 803         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 804         ds->ds_dir->dd_phys->dd_head_dataset_obj = 0;
 805         ddobj = ds->ds_dir->dd_object;
 806         ASSERT(ds->ds_phys->ds_snapnames_zapobj != 0);
 807         VERIFY0(zap_destroy(mos, ds->ds_phys->ds_snapnames_zapobj, tx));
 808
 809         spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
 810
 811         ASSERT0(ds->ds_phys->ds_next_clones_obj);
 812         ASSERT0(ds->ds_phys->ds_props_obj);
 813         ASSERT0(ds->ds_phys->ds_userrefs_obj);
 814         dsl_dir_rele(ds->ds_dir, ds);
 815         ds->ds_dir = NULL;
 816         dmu_object_free_zapified(mos, obj, tx);
 817
 818         dsl_dir_destroy_sync(ddobj, tx);
 819
 820         if (rmorigin) {
 821                 dsl_dataset_t *prev;
 822                 VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
 823                 dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
 824                 dsl_dataset_rele(prev, FTAG);
 825         }
 826 }
 827
 828 static void
 829 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
 830 {
 831         dsl_destroy_head_arg_t *ddha = arg;
 832         dsl_pool_t *dp = dmu_tx_pool(tx);
 833         dsl_dataset_t *ds;
 834
 835         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 836         dsl_destroy_head_sync_impl(ds, tx);
 837         dsl_dataset_rele(ds, FTAG);
 838 }
 839
 840 static void
 841 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
 842 {
 843         dsl_destroy_head_arg_t *ddha = arg;
 844         dsl_pool_t *dp = dmu_tx_pool(tx);
 845         dsl_dataset_t *ds;
 846
 847         VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
 848
 849         /* Mark it as inconsistent on-disk, in case we crash */
 850         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 851         ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
 852
 853         spa_history_log_internal_ds(ds, "destroy begin", tx, "");
 854         dsl_dataset_rele(ds, FTAG);
 855 }
 856
 857 int
 858 dsl_destroy_head(const char *name)
 859 {
 860         dsl_destroy_head_arg_t ddha;
 861         int error;
 862         spa_t *spa;
 863         boolean_t isenabled;
 864
 865 #ifdef _KERNEL
 866         zfs_destroy_unmount_origin(name);
 867 #endif
 868
 869         error = spa_open(name, &spa, FTAG);
 870         if (error != 0)
 871                 return (error);
 872         isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
 873         spa_close(spa, FTAG);
 874
 875         ddha.ddha_name = name;
 876
 877         if (!isenabled) {
 878                 objset_t *os;
 879
 880                 error = dsl_sync_task(name, dsl_destroy_head_check,
 881                     dsl_destroy_head_begin_sync, &ddha, 0);
 882                 if (error != 0)
 883                         return (error);
 884
 885                 /*
 886                  * Head deletion is processed in one txg on old pools;
 887                  * remove the objects from open context so that the txg sync
 888                  * is not too long.
 889                  */
 890                 error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, FTAG, &os);
 891                 if (error == 0) {
 892                         uint64_t prev_snap_txg =
 893                             dmu_objset_ds(os)->ds_phys->ds_prev_snap_txg;
 894                         for (uint64_t obj = 0; error == 0;
 895                             error = dmu_object_next(os, &obj, FALSE,
 896                             prev_snap_txg))
 897                                 (void) dmu_free_long_object(os, obj);
 898                         /* sync out all frees */
 899                         txg_wait_synced(dmu_objset_pool(os), 0);
 900                         dmu_objset_disown(os, FTAG);
 901                 }
 902         }
 903
 904         return (dsl_sync_task(name, dsl_destroy_head_check,
 905             dsl_destroy_head_sync, &ddha, 0));
 906 }
 907
 908 /*
 909  * Note, this function is used as the callback for dmu_objset_find().  We
 910  * always return 0 so that we will continue to find and process
 911  * inconsistent datasets, even if we encounter an error trying to
 912  * process one of them.
 913  */
 914 /* ARGSUSED */
 915 int
 916 dsl_destroy_inconsistent(const char *dsname, void *arg)
 917 {
 918         objset_t *os;
 919
 920         if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
 921                 boolean_t inconsistent = DS_IS_INCONSISTENT(dmu_objset_ds(os));
 922                 dmu_objset_rele(os, FTAG);
 923                 if (inconsistent)
 924                         (void) dsl_destroy_head(dsname);
 925         }
 926         return (0);
 927 }