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) 2012, Joyent, Inc. All rights reserved.
  25  */
  26 
  27 #include <sys/dmu_objset.h>
  28 #include <sys/dsl_dataset.h>
  29 #include <sys/dsl_dir.h>
  30 #include <sys/dsl_prop.h>
  31 #include <sys/dsl_synctask.h>
  32 #include <sys/dmu_traverse.h>
  33 #include <sys/dmu_impl.h>
  34 #include <sys/dmu_tx.h>
  35 #include <sys/arc.h>
  36 #include <sys/zio.h>
  37 #include <sys/zap.h>
  38 #include <sys/zfeature.h>
  39 #include <sys/unique.h>
  40 #include <sys/zfs_context.h>
  41 #include <sys/zfs_ioctl.h>
  42 #include <sys/spa.h>
  43 #include <sys/zfs_znode.h>
  44 #include <sys/zfs_onexit.h>
  45 #include <sys/zvol.h>
  46 #include <sys/dsl_scan.h>
  47 #include <sys/dsl_deadlist.h>
  48 #include <sys/dsl_destroy.h>
  49 #include <sys/dsl_userhold.h>
  50 
  51 #define SWITCH64(x, y) \
  52         { \
  53                 uint64_t __tmp = (x); \
  54                 (x) = (y); \
  55                 (y) = __tmp; \
  56         }
  57 
  58 #define DS_REF_MAX      (1ULL << 62)
  59 
  60 #define DSL_DEADLIST_BLOCKSIZE  SPA_MAXBLOCKSIZE
  61 
  62 /*
  63  * Figure out how much of this delta should be propogated to the dsl_dir
  64  * layer.  If there's a refreservation, that space has already been
  65  * partially accounted for in our ancestors.
  66  */
  67 static int64_t
  68 parent_delta(dsl_dataset_t *ds, int64_t delta)
  69 {
  70         uint64_t old_bytes, new_bytes;
  71 
  72         if (ds->ds_reserved == 0)
  73                 return (delta);
  74 
  75         old_bytes = MAX(ds->ds_phys->ds_unique_bytes, ds->ds_reserved);
  76         new_bytes = MAX(ds->ds_phys->ds_unique_bytes + delta, ds->ds_reserved);
  77 
  78         ASSERT3U(ABS((int64_t)(new_bytes - old_bytes)), <=, ABS(delta));
  79         return (new_bytes - old_bytes);
  80 }
  81 
  82 void
  83 dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
  84 {
  85         int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
  86         int compressed = BP_GET_PSIZE(bp);
  87         int uncompressed = BP_GET_UCSIZE(bp);
  88         int64_t delta;
  89 
  90         dprintf_bp(bp, "ds=%p", ds);
  91 
  92         ASSERT(dmu_tx_is_syncing(tx));
  93         /* It could have been compressed away to nothing */
  94         if (BP_IS_HOLE(bp))
  95                 return;
  96         ASSERT(BP_GET_TYPE(bp) != DMU_OT_NONE);
  97         ASSERT(DMU_OT_IS_VALID(BP_GET_TYPE(bp)));
  98         if (ds == NULL) {
  99                 dsl_pool_mos_diduse_space(tx->tx_pool,
 100                     used, compressed, uncompressed);
 101                 return;
 102         }
 103         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 104 
 105         mutex_enter(&ds->ds_dir->dd_lock);
 106         mutex_enter(&ds->ds_lock);
 107         delta = parent_delta(ds, used);
 108         ds->ds_phys->ds_referenced_bytes += used;
 109         ds->ds_phys->ds_compressed_bytes += compressed;
 110         ds->ds_phys->ds_uncompressed_bytes += uncompressed;
 111         ds->ds_phys->ds_unique_bytes += used;
 112         mutex_exit(&ds->ds_lock);
 113         dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
 114             compressed, uncompressed, tx);
 115         dsl_dir_transfer_space(ds->ds_dir, used - delta,
 116             DD_USED_REFRSRV, DD_USED_HEAD, tx);
 117         mutex_exit(&ds->ds_dir->dd_lock);
 118 }
 119 
 120 int
 121 dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
 122     boolean_t async)
 123 {
 124         if (BP_IS_HOLE(bp))
 125                 return (0);
 126 
 127         ASSERT(dmu_tx_is_syncing(tx));
 128         ASSERT(bp->blk_birth <= tx->tx_txg);
 129 
 130         int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
 131         int compressed = BP_GET_PSIZE(bp);
 132         int uncompressed = BP_GET_UCSIZE(bp);
 133 
 134         ASSERT(used > 0);
 135         if (ds == NULL) {
 136                 dsl_free(tx->tx_pool, tx->tx_txg, bp);
 137                 dsl_pool_mos_diduse_space(tx->tx_pool,
 138                     -used, -compressed, -uncompressed);
 139                 return (used);
 140         }
 141         ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool);
 142 
 143         ASSERT(!dsl_dataset_is_snapshot(ds));
 144         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 145 
 146         if (bp->blk_birth > ds->ds_phys->ds_prev_snap_txg) {
 147                 int64_t delta;
 148 
 149                 dprintf_bp(bp, "freeing ds=%llu", ds->ds_object);
 150                 dsl_free(tx->tx_pool, tx->tx_txg, bp);
 151 
 152                 mutex_enter(&ds->ds_dir->dd_lock);
 153                 mutex_enter(&ds->ds_lock);
 154                 ASSERT(ds->ds_phys->ds_unique_bytes >= used ||
 155                     !DS_UNIQUE_IS_ACCURATE(ds));
 156                 delta = parent_delta(ds, -used);
 157                 ds->ds_phys->ds_unique_bytes -= used;
 158                 mutex_exit(&ds->ds_lock);
 159                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 160                     delta, -compressed, -uncompressed, tx);
 161                 dsl_dir_transfer_space(ds->ds_dir, -used - delta,
 162                     DD_USED_REFRSRV, DD_USED_HEAD, tx);
 163                 mutex_exit(&ds->ds_dir->dd_lock);
 164         } else {
 165                 dprintf_bp(bp, "putting on dead list: %s", "");
 166                 if (async) {
 167                         /*
 168                          * We are here as part of zio's write done callback,
 169                          * which means we're a zio interrupt thread.  We can't
 170                          * call dsl_deadlist_insert() now because it may block
 171                          * waiting for I/O.  Instead, put bp on the deferred
 172                          * queue and let dsl_pool_sync() finish the job.
 173                          */
 174                         bplist_append(&ds->ds_pending_deadlist, bp);
 175                 } else {
 176                         dsl_deadlist_insert(&ds->ds_deadlist, bp, tx);
 177                 }
 178                 ASSERT3U(ds->ds_prev->ds_object, ==,
 179                     ds->ds_phys->ds_prev_snap_obj);
 180                 ASSERT(ds->ds_prev->ds_phys->ds_num_children > 0);
 181                 /* if (bp->blk_birth > prev prev snap txg) prev unique += bs */
 182                 if (ds->ds_prev->ds_phys->ds_next_snap_obj ==
 183                     ds->ds_object && bp->blk_birth >
 184                     ds->ds_prev->ds_phys->ds_prev_snap_txg) {
 185                         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 186                         mutex_enter(&ds->ds_prev->ds_lock);
 187                         ds->ds_prev->ds_phys->ds_unique_bytes += used;
 188                         mutex_exit(&ds->ds_prev->ds_lock);
 189                 }
 190                 if (bp->blk_birth > ds->ds_dir->dd_origin_txg) {
 191                         dsl_dir_transfer_space(ds->ds_dir, used,
 192                             DD_USED_HEAD, DD_USED_SNAP, tx);
 193                 }
 194         }
 195         mutex_enter(&ds->ds_lock);
 196         ASSERT3U(ds->ds_phys->ds_referenced_bytes, >=, used);
 197         ds->ds_phys->ds_referenced_bytes -= used;
 198         ASSERT3U(ds->ds_phys->ds_compressed_bytes, >=, compressed);
 199         ds->ds_phys->ds_compressed_bytes -= compressed;
 200         ASSERT3U(ds->ds_phys->ds_uncompressed_bytes, >=, uncompressed);
 201         ds->ds_phys->ds_uncompressed_bytes -= uncompressed;
 202         mutex_exit(&ds->ds_lock);
 203 
 204         return (used);
 205 }
 206 
 207 uint64_t
 208 dsl_dataset_prev_snap_txg(dsl_dataset_t *ds)
 209 {
 210         uint64_t trysnap = 0;
 211 
 212         if (ds == NULL)
 213                 return (0);
 214         /*
 215          * The snapshot creation could fail, but that would cause an
 216          * incorrect FALSE return, which would only result in an
 217          * overestimation of the amount of space that an operation would
 218          * consume, which is OK.
 219          *
 220          * There's also a small window where we could miss a pending
 221          * snapshot, because we could set the sync task in the quiescing
 222          * phase.  So this should only be used as a guess.
 223          */
 224         if (ds->ds_trysnap_txg >
 225             spa_last_synced_txg(ds->ds_dir->dd_pool->dp_spa))
 226                 trysnap = ds->ds_trysnap_txg;
 227         return (MAX(ds->ds_phys->ds_prev_snap_txg, trysnap));
 228 }
 229 
 230 boolean_t
 231 dsl_dataset_block_freeable(dsl_dataset_t *ds, const blkptr_t *bp,
 232     uint64_t blk_birth)
 233 {
 234         if (blk_birth <= dsl_dataset_prev_snap_txg(ds))
 235                 return (B_FALSE);
 236 
 237         ddt_prefetch(dsl_dataset_get_spa(ds), bp);
 238 
 239         return (B_TRUE);
 240 }
 241 
 242 /* ARGSUSED */
 243 static void
 244 dsl_dataset_evict(dmu_buf_t *db, void *dsv)
 245 {
 246         dsl_dataset_t *ds = dsv;
 247 
 248         ASSERT(ds->ds_owner == NULL);
 249 
 250         unique_remove(ds->ds_fsid_guid);
 251 
 252         if (ds->ds_objset != NULL)
 253                 dmu_objset_evict(ds->ds_objset);
 254 
 255         if (ds->ds_prev) {
 256                 dsl_dataset_rele(ds->ds_prev, ds);
 257                 ds->ds_prev = NULL;
 258         }
 259 
 260         bplist_destroy(&ds->ds_pending_deadlist);
 261         if (ds->ds_phys->ds_deadlist_obj != 0)
 262                 dsl_deadlist_close(&ds->ds_deadlist);
 263         if (ds->ds_dir)
 264                 dsl_dir_rele(ds->ds_dir, ds);
 265 
 266         ASSERT(!list_link_active(&ds->ds_synced_link));
 267 
 268         mutex_destroy(&ds->ds_lock);
 269         mutex_destroy(&ds->ds_opening_lock);
 270         refcount_destroy(&ds->ds_longholds);
 271 
 272         kmem_free(ds, sizeof (dsl_dataset_t));
 273 }
 274 
 275 int
 276 dsl_dataset_get_snapname(dsl_dataset_t *ds)
 277 {
 278         dsl_dataset_phys_t *headphys;
 279         int err;
 280         dmu_buf_t *headdbuf;
 281         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 282         objset_t *mos = dp->dp_meta_objset;
 283 
 284         if (ds->ds_snapname[0])
 285                 return (0);
 286         if (ds->ds_phys->ds_next_snap_obj == 0)
 287                 return (0);
 288 
 289         err = dmu_bonus_hold(mos, ds->ds_dir->dd_phys->dd_head_dataset_obj,
 290             FTAG, &headdbuf);
 291         if (err != 0)
 292                 return (err);
 293         headphys = headdbuf->db_data;
 294         err = zap_value_search(dp->dp_meta_objset,
 295             headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
 296         dmu_buf_rele(headdbuf, FTAG);
 297         return (err);
 298 }
 299 
 300 int
 301 dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value)
 302 {
 303         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 304         uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
 305         matchtype_t mt;
 306         int err;
 307 
 308         if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
 309                 mt = MT_FIRST;
 310         else
 311                 mt = MT_EXACT;
 312 
 313         err = zap_lookup_norm(mos, snapobj, name, 8, 1,
 314             value, mt, NULL, 0, NULL);
 315         if (err == ENOTSUP && mt == MT_FIRST)
 316                 err = zap_lookup(mos, snapobj, name, 8, 1, value);
 317         return (err);
 318 }
 319 
 320 int
 321 dsl_dataset_snap_remove(dsl_dataset_t *ds, const char *name, dmu_tx_t *tx)
 322 {
 323         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 324         uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
 325         matchtype_t mt;
 326         int err;
 327 
 328         dsl_dir_snap_cmtime_update(ds->ds_dir);
 329 
 330         if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
 331                 mt = MT_FIRST;
 332         else
 333                 mt = MT_EXACT;
 334 
 335         err = zap_remove_norm(mos, snapobj, name, mt, tx);
 336         if (err == ENOTSUP && mt == MT_FIRST)
 337                 err = zap_remove(mos, snapobj, name, tx);
 338         return (err);
 339 }
 340 
 341 int
 342 dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
 343     dsl_dataset_t **dsp)
 344 {
 345         objset_t *mos = dp->dp_meta_objset;
 346         dmu_buf_t *dbuf;
 347         dsl_dataset_t *ds;
 348         int err;
 349         dmu_object_info_t doi;
 350 
 351         ASSERT(dsl_pool_config_held(dp));
 352 
 353         err = dmu_bonus_hold(mos, dsobj, tag, &dbuf);
 354         if (err != 0)
 355                 return (err);
 356 
 357         /* Make sure dsobj has the correct object type. */
 358         dmu_object_info_from_db(dbuf, &doi);
 359         if (doi.doi_type != DMU_OT_DSL_DATASET)
 360                 return (SET_ERROR(EINVAL));
 361 
 362         ds = dmu_buf_get_user(dbuf);
 363         if (ds == NULL) {
 364                 dsl_dataset_t *winner = NULL;
 365 
 366                 ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP);
 367                 ds->ds_dbuf = dbuf;
 368                 ds->ds_object = dsobj;
 369                 ds->ds_phys = dbuf->db_data;
 370 
 371                 mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
 372                 mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
 373                 mutex_init(&ds->ds_sendstream_lock, NULL, MUTEX_DEFAULT, NULL);
 374                 refcount_create(&ds->ds_longholds);
 375 
 376                 bplist_create(&ds->ds_pending_deadlist);
 377                 dsl_deadlist_open(&ds->ds_deadlist,
 378                     mos, ds->ds_phys->ds_deadlist_obj);
 379 
 380                 list_create(&ds->ds_sendstreams, sizeof (dmu_sendarg_t),
 381                     offsetof(dmu_sendarg_t, dsa_link));
 382 
 383                 if (err == 0) {
 384                         err = dsl_dir_hold_obj(dp,
 385                             ds->ds_phys->ds_dir_obj, NULL, ds, &ds->ds_dir);
 386                 }
 387                 if (err != 0) {
 388                         mutex_destroy(&ds->ds_lock);
 389                         mutex_destroy(&ds->ds_opening_lock);
 390                         refcount_destroy(&ds->ds_longholds);
 391                         bplist_destroy(&ds->ds_pending_deadlist);
 392                         dsl_deadlist_close(&ds->ds_deadlist);
 393                         kmem_free(ds, sizeof (dsl_dataset_t));
 394                         dmu_buf_rele(dbuf, tag);
 395                         return (err);
 396                 }
 397 
 398                 if (!dsl_dataset_is_snapshot(ds)) {
 399                         ds->ds_snapname[0] = '\0';
 400                         if (ds->ds_phys->ds_prev_snap_obj != 0) {
 401                                 err = dsl_dataset_hold_obj(dp,
 402                                     ds->ds_phys->ds_prev_snap_obj,
 403                                     ds, &ds->ds_prev);
 404                         }
 405                 } else {
 406                         if (zfs_flags & ZFS_DEBUG_SNAPNAMES)
 407                                 err = dsl_dataset_get_snapname(ds);
 408                         if (err == 0 && ds->ds_phys->ds_userrefs_obj != 0) {
 409                                 err = zap_count(
 410                                     ds->ds_dir->dd_pool->dp_meta_objset,
 411                                     ds->ds_phys->ds_userrefs_obj,
 412                                     &ds->ds_userrefs);
 413                         }
 414                 }
 415 
 416                 if (err == 0 && !dsl_dataset_is_snapshot(ds)) {
 417                         err = dsl_prop_get_int_ds(ds,
 418                             zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
 419                             &ds->ds_reserved);
 420                         if (err == 0) {
 421                                 err = dsl_prop_get_int_ds(ds,
 422                                     zfs_prop_to_name(ZFS_PROP_REFQUOTA),
 423                                     &ds->ds_quota);
 424                         }
 425                 } else {
 426                         ds->ds_reserved = ds->ds_quota = 0;
 427                 }
 428 
 429                 if (err != 0 || (winner = dmu_buf_set_user_ie(dbuf, ds,
 430                     &ds->ds_phys, dsl_dataset_evict)) != NULL) {
 431                         bplist_destroy(&ds->ds_pending_deadlist);
 432                         dsl_deadlist_close(&ds->ds_deadlist);
 433                         if (ds->ds_prev)
 434                                 dsl_dataset_rele(ds->ds_prev, ds);
 435                         dsl_dir_rele(ds->ds_dir, ds);
 436                         mutex_destroy(&ds->ds_lock);
 437                         mutex_destroy(&ds->ds_opening_lock);
 438                         refcount_destroy(&ds->ds_longholds);
 439                         kmem_free(ds, sizeof (dsl_dataset_t));
 440                         if (err != 0) {
 441                                 dmu_buf_rele(dbuf, tag);
 442                                 return (err);
 443                         }
 444                         ds = winner;
 445                 } else {
 446                         ds->ds_fsid_guid =
 447                             unique_insert(ds->ds_phys->ds_fsid_guid);
 448                 }
 449         }
 450         ASSERT3P(ds->ds_dbuf, ==, dbuf);
 451         ASSERT3P(ds->ds_phys, ==, dbuf->db_data);
 452         ASSERT(ds->ds_phys->ds_prev_snap_obj != 0 ||
 453             spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
 454             dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
 455         *dsp = ds;
 456         return (0);
 457 }
 458 
 459 int
 460 dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 461     void *tag, dsl_dataset_t **dsp)
 462 {
 463         dsl_dir_t *dd;
 464         const char *snapname;
 465         uint64_t obj;
 466         int err = 0;
 467 
 468         err = dsl_dir_hold(dp, name, FTAG, &dd, &snapname);
 469         if (err != 0)
 470                 return (err);
 471 
 472         ASSERT(dsl_pool_config_held(dp));
 473         obj = dd->dd_phys->dd_head_dataset_obj;
 474         if (obj != 0)
 475                 err = dsl_dataset_hold_obj(dp, obj, tag, dsp);
 476         else
 477                 err = SET_ERROR(ENOENT);
 478 
 479         /* we may be looking for a snapshot */
 480         if (err == 0 && snapname != NULL) {
 481                 dsl_dataset_t *ds;
 482 
 483                 if (*snapname++ != '@') {
 484                         dsl_dataset_rele(*dsp, tag);
 485                         dsl_dir_rele(dd, FTAG);
 486                         return (SET_ERROR(ENOENT));
 487                 }
 488 
 489                 dprintf("looking for snapshot '%s'\n", snapname);
 490                 err = dsl_dataset_snap_lookup(*dsp, snapname, &obj);
 491                 if (err == 0)
 492                         err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
 493                 dsl_dataset_rele(*dsp, tag);
 494 
 495                 if (err == 0) {
 496                         mutex_enter(&ds->ds_lock);
 497                         if (ds->ds_snapname[0] == 0)
 498                                 (void) strlcpy(ds->ds_snapname, snapname,
 499                                     sizeof (ds->ds_snapname));
 500                         mutex_exit(&ds->ds_lock);
 501                         *dsp = ds;
 502                 }
 503         }
 504 
 505         dsl_dir_rele(dd, FTAG);
 506         return (err);
 507 }
 508 
 509 int
 510 dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj,
 511     void *tag, dsl_dataset_t **dsp)
 512 {
 513         int err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp);
 514         if (err != 0)
 515                 return (err);
 516         if (!dsl_dataset_tryown(*dsp, tag)) {
 517                 dsl_dataset_rele(*dsp, tag);
 518                 *dsp = NULL;
 519                 return (SET_ERROR(EBUSY));
 520         }
 521         return (0);
 522 }
 523 
 524 int
 525 dsl_dataset_own(dsl_pool_t *dp, const char *name,
 526     void *tag, dsl_dataset_t **dsp)
 527 {
 528         int err = dsl_dataset_hold(dp, name, tag, dsp);
 529         if (err != 0)
 530                 return (err);
 531         if (!dsl_dataset_tryown(*dsp, tag)) {
 532                 dsl_dataset_rele(*dsp, tag);
 533                 return (SET_ERROR(EBUSY));
 534         }
 535         return (0);
 536 }
 537 
 538 /*
 539  * See the comment above dsl_pool_hold() for details.  In summary, a long
 540  * hold is used to prevent destruction of a dataset while the pool hold
 541  * is dropped, allowing other concurrent operations (e.g. spa_sync()).
 542  *
 543  * The dataset and pool must be held when this function is called.  After it
 544  * is called, the pool hold may be released while the dataset is still held
 545  * and accessed.
 546  */
 547 void
 548 dsl_dataset_long_hold(dsl_dataset_t *ds, void *tag)
 549 {
 550         ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
 551         (void) refcount_add(&ds->ds_longholds, tag);
 552 }
 553 
 554 void
 555 dsl_dataset_long_rele(dsl_dataset_t *ds, void *tag)
 556 {
 557         (void) refcount_remove(&ds->ds_longholds, tag);
 558 }
 559 
 560 /* Return B_TRUE if there are any long holds on this dataset. */
 561 boolean_t
 562 dsl_dataset_long_held(dsl_dataset_t *ds)
 563 {
 564         return (!refcount_is_zero(&ds->ds_longholds));
 565 }
 566 
 567 void
 568 dsl_dataset_name(dsl_dataset_t *ds, char *name)
 569 {
 570         if (ds == NULL) {
 571                 (void) strcpy(name, "mos");
 572         } else {
 573                 dsl_dir_name(ds->ds_dir, name);
 574                 VERIFY0(dsl_dataset_get_snapname(ds));
 575                 if (ds->ds_snapname[0]) {
 576                         (void) strcat(name, "@");
 577                         /*
 578                          * We use a "recursive" mutex so that we
 579                          * can call dprintf_ds() with ds_lock held.
 580                          */
 581                         if (!MUTEX_HELD(&ds->ds_lock)) {
 582                                 mutex_enter(&ds->ds_lock);
 583                                 (void) strcat(name, ds->ds_snapname);
 584                                 mutex_exit(&ds->ds_lock);
 585                         } else {
 586                                 (void) strcat(name, ds->ds_snapname);
 587                         }
 588                 }
 589         }
 590 }
 591 
 592 static int
 593 dsl_dataset_namelen(dsl_dataset_t *ds)
 594 {
 595         int result;
 596 
 597         if (ds == NULL) {
 598                 result = 3;     /* "mos" */
 599         } else {
 600                 result = dsl_dir_namelen(ds->ds_dir);
 601                 VERIFY0(dsl_dataset_get_snapname(ds));
 602                 if (ds->ds_snapname[0]) {
 603                         ++result;       /* adding one for the @-sign */
 604                         if (!MUTEX_HELD(&ds->ds_lock)) {
 605                                 mutex_enter(&ds->ds_lock);
 606                                 result += strlen(ds->ds_snapname);
 607                                 mutex_exit(&ds->ds_lock);
 608                         } else {
 609                                 result += strlen(ds->ds_snapname);
 610                         }
 611                 }
 612         }
 613 
 614         return (result);
 615 }
 616 
 617 void
 618 dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
 619 {
 620         dmu_buf_rele(ds->ds_dbuf, tag);
 621 }
 622 
 623 void
 624 dsl_dataset_disown(dsl_dataset_t *ds, void *tag)
 625 {
 626         ASSERT(ds->ds_owner == tag && ds->ds_dbuf != NULL);
 627 
 628         mutex_enter(&ds->ds_lock);
 629         ds->ds_owner = NULL;
 630         mutex_exit(&ds->ds_lock);
 631         dsl_dataset_long_rele(ds, tag);
 632         if (ds->ds_dbuf != NULL)
 633                 dsl_dataset_rele(ds, tag);
 634         else
 635                 dsl_dataset_evict(NULL, ds);
 636 }
 637 
 638 boolean_t
 639 dsl_dataset_tryown(dsl_dataset_t *ds, void *tag)
 640 {
 641         boolean_t gotit = FALSE;
 642 
 643         mutex_enter(&ds->ds_lock);
 644         if (ds->ds_owner == NULL && !DS_IS_INCONSISTENT(ds)) {
 645                 ds->ds_owner = tag;
 646                 dsl_dataset_long_hold(ds, tag);
 647                 gotit = TRUE;
 648         }
 649         mutex_exit(&ds->ds_lock);
 650         return (gotit);
 651 }
 652 
 653 uint64_t
 654 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
 655     uint64_t flags, dmu_tx_t *tx)
 656 {
 657         dsl_pool_t *dp = dd->dd_pool;
 658         dmu_buf_t *dbuf;
 659         dsl_dataset_phys_t *dsphys;
 660         uint64_t dsobj;
 661         objset_t *mos = dp->dp_meta_objset;
 662 
 663         if (origin == NULL)
 664                 origin = dp->dp_origin_snap;
 665 
 666         ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
 667         ASSERT(origin == NULL || origin->ds_phys->ds_num_children > 0);
 668         ASSERT(dmu_tx_is_syncing(tx));
 669         ASSERT(dd->dd_phys->dd_head_dataset_obj == 0);
 670 
 671         dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
 672             DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
 673         VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
 674         dmu_buf_will_dirty(dbuf, tx);
 675         dsphys = dbuf->db_data;
 676         bzero(dsphys, sizeof (dsl_dataset_phys_t));
 677         dsphys->ds_dir_obj = dd->dd_object;
 678         dsphys->ds_flags = flags;
 679         dsphys->ds_fsid_guid = unique_create();
 680         (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
 681             sizeof (dsphys->ds_guid));
 682         dsphys->ds_snapnames_zapobj =
 683             zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP,
 684             DMU_OT_NONE, 0, tx);
 685         dsphys->ds_creation_time = gethrestime_sec();
 686         dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg;
 687 
 688         if (origin == NULL) {
 689                 dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx);
 690         } else {
 691                 dsl_dataset_t *ohds; /* head of the origin snapshot */
 692 
 693                 dsphys->ds_prev_snap_obj = origin->ds_object;
 694                 dsphys->ds_prev_snap_txg =
 695                     origin->ds_phys->ds_creation_txg;
 696                 dsphys->ds_referenced_bytes =
 697                     origin->ds_phys->ds_referenced_bytes;
 698                 dsphys->ds_compressed_bytes =
 699                     origin->ds_phys->ds_compressed_bytes;
 700                 dsphys->ds_uncompressed_bytes =
 701                     origin->ds_phys->ds_uncompressed_bytes;
 702                 dsphys->ds_bp = origin->ds_phys->ds_bp;
 703                 dsphys->ds_flags |= origin->ds_phys->ds_flags;
 704 
 705                 dmu_buf_will_dirty(origin->ds_dbuf, tx);
 706                 origin->ds_phys->ds_num_children++;
 707 
 708                 VERIFY0(dsl_dataset_hold_obj(dp,
 709                     origin->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &ohds));
 710                 dsphys->ds_deadlist_obj = dsl_deadlist_clone(&ohds->ds_deadlist,
 711                     dsphys->ds_prev_snap_txg, dsphys->ds_prev_snap_obj, tx);
 712                 dsl_dataset_rele(ohds, FTAG);
 713 
 714                 if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) {
 715                         if (origin->ds_phys->ds_next_clones_obj == 0) {
 716                                 origin->ds_phys->ds_next_clones_obj =
 717                                     zap_create(mos,
 718                                     DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
 719                         }
 720                         VERIFY0(zap_add_int(mos,
 721                             origin->ds_phys->ds_next_clones_obj, dsobj, tx));
 722                 }
 723 
 724                 dmu_buf_will_dirty(dd->dd_dbuf, tx);
 725                 dd->dd_phys->dd_origin_obj = origin->ds_object;
 726                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 727                         if (origin->ds_dir->dd_phys->dd_clones == 0) {
 728                                 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
 729                                 origin->ds_dir->dd_phys->dd_clones =
 730                                     zap_create(mos,
 731                                     DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
 732                         }
 733                         VERIFY0(zap_add_int(mos,
 734                             origin->ds_dir->dd_phys->dd_clones, dsobj, tx));
 735                 }
 736         }
 737 
 738         if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
 739                 dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
 740 
 741         dmu_buf_rele(dbuf, FTAG);
 742 
 743         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 744         dd->dd_phys->dd_head_dataset_obj = dsobj;
 745 
 746         return (dsobj);
 747 }
 748 
 749 static void
 750 dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
 751 {
 752         objset_t *os;
 753 
 754         VERIFY0(dmu_objset_from_ds(ds, &os));
 755         bzero(&os->os_zil_header, sizeof (os->os_zil_header));
 756         dsl_dataset_dirty(ds, tx);
 757 }
 758 
 759 uint64_t
 760 dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
 761     dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx)
 762 {
 763         dsl_pool_t *dp = pdd->dd_pool;
 764         uint64_t dsobj, ddobj;
 765         dsl_dir_t *dd;
 766 
 767         ASSERT(dmu_tx_is_syncing(tx));
 768         ASSERT(lastname[0] != '@');
 769 
 770         ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
 771         VERIFY0(dsl_dir_hold_obj(dp, ddobj, lastname, FTAG, &dd));
 772 
 773         dsobj = dsl_dataset_create_sync_dd(dd, origin,
 774             flags & ~DS_CREATE_FLAG_NODIRTY, tx);
 775 
 776         dsl_deleg_set_create_perms(dd, tx, cr);
 777 
 778         dsl_dir_rele(dd, FTAG);
 779 
 780         /*
 781          * If we are creating a clone, make sure we zero out any stale
 782          * data from the origin snapshots zil header.
 783          */
 784         if (origin != NULL && !(flags & DS_CREATE_FLAG_NODIRTY)) {
 785                 dsl_dataset_t *ds;
 786 
 787                 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
 788                 dsl_dataset_zero_zil(ds, tx);
 789                 dsl_dataset_rele(ds, FTAG);
 790         }
 791 
 792         return (dsobj);
 793 }
 794 
 795 /*
 796  * The unique space in the head dataset can be calculated by subtracting
 797  * the space used in the most recent snapshot, that is still being used
 798  * in this file system, from the space currently in use.  To figure out
 799  * the space in the most recent snapshot still in use, we need to take
 800  * the total space used in the snapshot and subtract out the space that
 801  * has been freed up since the snapshot was taken.
 802  */
 803 void
 804 dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
 805 {
 806         uint64_t mrs_used;
 807         uint64_t dlused, dlcomp, dluncomp;
 808 
 809         ASSERT(!dsl_dataset_is_snapshot(ds));
 810 
 811         if (ds->ds_phys->ds_prev_snap_obj != 0)
 812                 mrs_used = ds->ds_prev->ds_phys->ds_referenced_bytes;
 813         else
 814                 mrs_used = 0;
 815 
 816         dsl_deadlist_space(&ds->ds_deadlist, &dlused, &dlcomp, &dluncomp);
 817 
 818         ASSERT3U(dlused, <=, mrs_used);
 819         ds->ds_phys->ds_unique_bytes =
 820             ds->ds_phys->ds_referenced_bytes - (mrs_used - dlused);
 821 
 822         if (spa_version(ds->ds_dir->dd_pool->dp_spa) >=
 823             SPA_VERSION_UNIQUE_ACCURATE)
 824                 ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
 825 }
 826 
 827 void
 828 dsl_dataset_remove_from_next_clones(dsl_dataset_t *ds, uint64_t obj,
 829     dmu_tx_t *tx)
 830 {
 831         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 832         uint64_t count;
 833         int err;
 834 
 835         ASSERT(ds->ds_phys->ds_num_children >= 2);
 836         err = zap_remove_int(mos, ds->ds_phys->ds_next_clones_obj, obj, tx);
 837         /*
 838          * The err should not be ENOENT, but a bug in a previous version
 839          * of the code could cause upgrade_clones_cb() to not set
 840          * ds_next_snap_obj when it should, leading to a missing entry.
 841          * If we knew that the pool was created after
 842          * SPA_VERSION_NEXT_CLONES, we could assert that it isn't
 843          * ENOENT.  However, at least we can check that we don't have
 844          * too many entries in the next_clones_obj even after failing to
 845          * remove this one.
 846          */
 847         if (err != ENOENT)
 848                 VERIFY0(err);
 849         ASSERT0(zap_count(mos, ds->ds_phys->ds_next_clones_obj,
 850             &count));
 851         ASSERT3U(count, <=, ds->ds_phys->ds_num_children - 2);
 852 }
 853 
 854 
 855 blkptr_t *
 856 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
 857 {
 858         return (&ds->ds_phys->ds_bp);
 859 }
 860 
 861 void
 862 dsl_dataset_set_blkptr(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
 863 {
 864         ASSERT(dmu_tx_is_syncing(tx));
 865         /* If it's the meta-objset, set dp_meta_rootbp */
 866         if (ds == NULL) {
 867                 tx->tx_pool->dp_meta_rootbp = *bp;
 868         } else {
 869                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 870                 ds->ds_phys->ds_bp = *bp;
 871         }
 872 }
 873 
 874 spa_t *
 875 dsl_dataset_get_spa(dsl_dataset_t *ds)
 876 {
 877         return (ds->ds_dir->dd_pool->dp_spa);
 878 }
 879 
 880 void
 881 dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
 882 {
 883         dsl_pool_t *dp;
 884 
 885         if (ds == NULL) /* this is the meta-objset */
 886                 return;
 887 
 888         ASSERT(ds->ds_objset != NULL);
 889 
 890         if (ds->ds_phys->ds_next_snap_obj != 0)
 891                 panic("dirtying snapshot!");
 892 
 893         dp = ds->ds_dir->dd_pool;
 894 
 895         if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg)) {
 896                 /* up the hold count until we can be written out */
 897                 dmu_buf_add_ref(ds->ds_dbuf, ds);
 898         }
 899 }
 900 
 901 boolean_t
 902 dsl_dataset_is_dirty(dsl_dataset_t *ds)
 903 {
 904         for (int t = 0; t < TXG_SIZE; t++) {
 905                 if (txg_list_member(&ds->ds_dir->dd_pool->dp_dirty_datasets,
 906                     ds, t))
 907                         return (B_TRUE);
 908         }
 909         return (B_FALSE);
 910 }
 911 
 912 static int
 913 dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx)
 914 {
 915         uint64_t asize;
 916 
 917         if (!dmu_tx_is_syncing(tx))
 918                 return (0);
 919 
 920         /*
 921          * If there's an fs-only reservation, any blocks that might become
 922          * owned by the snapshot dataset must be accommodated by space
 923          * outside of the reservation.
 924          */
 925         ASSERT(ds->ds_reserved == 0 || DS_UNIQUE_IS_ACCURATE(ds));
 926         asize = MIN(ds->ds_phys->ds_unique_bytes, ds->ds_reserved);
 927         if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE))
 928                 return (SET_ERROR(ENOSPC));
 929 
 930         /*
 931          * Propagate any reserved space for this snapshot to other
 932          * snapshot checks in this sync group.
 933          */
 934         if (asize > 0)
 935                 dsl_dir_willuse_space(ds->ds_dir, asize, tx);
 936 
 937         return (0);
 938 }
 939 
 940 typedef struct dsl_dataset_snapshot_arg {
 941         nvlist_t *ddsa_snaps;
 942         nvlist_t *ddsa_props;
 943         nvlist_t *ddsa_errors;
 944 } dsl_dataset_snapshot_arg_t;
 945 
 946 int
 947 dsl_dataset_snapshot_check_impl(dsl_dataset_t *ds, const char *snapname,
 948     dmu_tx_t *tx)
 949 {
 950         int error;
 951         uint64_t value;
 952 
 953         ds->ds_trysnap_txg = tx->tx_txg;
 954 
 955         if (!dmu_tx_is_syncing(tx))
 956                 return (0);
 957 
 958         /*
 959          * We don't allow multiple snapshots of the same txg.  If there
 960          * is already one, try again.
 961          */
 962         if (ds->ds_phys->ds_prev_snap_txg >= tx->tx_txg)
 963                 return (SET_ERROR(EAGAIN));
 964 
 965         /*
 966          * Check for conflicting snapshot name.
 967          */
 968         error = dsl_dataset_snap_lookup(ds, snapname, &value);
 969         if (error == 0)
 970                 return (SET_ERROR(EEXIST));
 971         if (error != ENOENT)
 972                 return (error);
 973 
 974         error = dsl_dataset_snapshot_reserve_space(ds, tx);
 975         if (error != 0)
 976                 return (error);
 977 
 978         return (0);
 979 }
 980 
 981 static int
 982 dsl_dataset_snapshot_check(void *arg, dmu_tx_t *tx)
 983 {
 984         dsl_dataset_snapshot_arg_t *ddsa = arg;
 985         dsl_pool_t *dp = dmu_tx_pool(tx);
 986         nvpair_t *pair;
 987         int rv = 0;
 988 
 989         for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
 990             pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
 991                 int error = 0;
 992                 dsl_dataset_t *ds;
 993                 char *name, *atp;
 994                 char dsname[MAXNAMELEN];
 995 
 996                 name = nvpair_name(pair);
 997                 if (strlen(name) >= MAXNAMELEN)
 998                         error = SET_ERROR(ENAMETOOLONG);
 999                 if (error == 0) {
1000                         atp = strchr(name, '@');
1001                         if (atp == NULL)
1002                                 error = SET_ERROR(EINVAL);
1003                         if (error == 0)
1004                                 (void) strlcpy(dsname, name, atp - name + 1);
1005                 }
1006                 if (error == 0)
1007                         error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
1008                 if (error == 0) {
1009                         error = dsl_dataset_snapshot_check_impl(ds,
1010                             atp + 1, tx);
1011                         dsl_dataset_rele(ds, FTAG);
1012                 }
1013 
1014                 if (error != 0) {
1015                         if (ddsa->ddsa_errors != NULL) {
1016                                 fnvlist_add_int32(ddsa->ddsa_errors,
1017                                     name, error);
1018                         }
1019                         rv = error;
1020                 }
1021         }
1022         return (rv);
1023 }
1024 
1025 void
1026 dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
1027     dmu_tx_t *tx)
1028 {
1029         static zil_header_t zero_zil;
1030 
1031         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1032         dmu_buf_t *dbuf;
1033         dsl_dataset_phys_t *dsphys;
1034         uint64_t dsobj, crtxg;
1035         objset_t *mos = dp->dp_meta_objset;
1036         objset_t *os;
1037 
1038         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
1039 
1040         /*
1041          * If we are on an old pool, the zil must not be active, in which
1042          * case it will be zeroed.  Usually zil_suspend() accomplishes this.
1043          */
1044         ASSERT(spa_version(dmu_tx_pool(tx)->dp_spa) >= SPA_VERSION_FAST_SNAP ||
1045             dmu_objset_from_ds(ds, &os) != 0 ||
1046             bcmp(&os->os_phys->os_zil_header, &zero_zil,
1047             sizeof (zero_zil)) == 0);
1048 
1049 
1050         /*
1051          * The origin's ds_creation_txg has to be < TXG_INITIAL
1052          */
1053         if (strcmp(snapname, ORIGIN_DIR_NAME) == 0)
1054                 crtxg = 1;
1055         else
1056                 crtxg = tx->tx_txg;
1057 
1058         dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1059             DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1060         VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1061         dmu_buf_will_dirty(dbuf, tx);
1062         dsphys = dbuf->db_data;
1063         bzero(dsphys, sizeof (dsl_dataset_phys_t));
1064         dsphys->ds_dir_obj = ds->ds_dir->dd_object;
1065         dsphys->ds_fsid_guid = unique_create();
1066         (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1067             sizeof (dsphys->ds_guid));
1068         dsphys->ds_prev_snap_obj = ds->ds_phys->ds_prev_snap_obj;
1069         dsphys->ds_prev_snap_txg = ds->ds_phys->ds_prev_snap_txg;
1070         dsphys->ds_next_snap_obj = ds->ds_object;
1071         dsphys->ds_num_children = 1;
1072         dsphys->ds_creation_time = gethrestime_sec();
1073         dsphys->ds_creation_txg = crtxg;
1074         dsphys->ds_deadlist_obj = ds->ds_phys->ds_deadlist_obj;
1075         dsphys->ds_referenced_bytes = ds->ds_phys->ds_referenced_bytes;
1076         dsphys->ds_compressed_bytes = ds->ds_phys->ds_compressed_bytes;
1077         dsphys->ds_uncompressed_bytes = ds->ds_phys->ds_uncompressed_bytes;
1078         dsphys->ds_flags = ds->ds_phys->ds_flags;
1079         dsphys->ds_bp = ds->ds_phys->ds_bp;
1080         dmu_buf_rele(dbuf, FTAG);
1081 
1082         ASSERT3U(ds->ds_prev != 0, ==, ds->ds_phys->ds_prev_snap_obj != 0);
1083         if (ds->ds_prev) {
1084                 uint64_t next_clones_obj =
1085                     ds->ds_prev->ds_phys->ds_next_clones_obj;
1086                 ASSERT(ds->ds_prev->ds_phys->ds_next_snap_obj ==
1087                     ds->ds_object ||
1088                     ds->ds_prev->ds_phys->ds_num_children > 1);
1089                 if (ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) {
1090                         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1091                         ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==,
1092                             ds->ds_prev->ds_phys->ds_creation_txg);
1093                         ds->ds_prev->ds_phys->ds_next_snap_obj = dsobj;
1094                 } else if (next_clones_obj != 0) {
1095                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
1096                             dsphys->ds_next_snap_obj, tx);
1097                         VERIFY0(zap_add_int(mos,
1098                             next_clones_obj, dsobj, tx));
1099                 }
1100         }
1101 
1102         /*
1103          * If we have a reference-reservation on this dataset, we will
1104          * need to increase the amount of refreservation being charged
1105          * since our unique space is going to zero.
1106          */
1107         if (ds->ds_reserved) {
1108                 int64_t delta;
1109                 ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
1110                 delta = MIN(ds->ds_phys->ds_unique_bytes, ds->ds_reserved);
1111                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV,
1112                     delta, 0, 0, tx);
1113         }
1114 
1115         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1116         ds->ds_phys->ds_deadlist_obj = dsl_deadlist_clone(&ds->ds_deadlist,
1117             UINT64_MAX, ds->ds_phys->ds_prev_snap_obj, tx);
1118         dsl_deadlist_close(&ds->ds_deadlist);
1119         dsl_deadlist_open(&ds->ds_deadlist, mos, ds->ds_phys->ds_deadlist_obj);
1120         dsl_deadlist_add_key(&ds->ds_deadlist,
1121             ds->ds_phys->ds_prev_snap_txg, tx);
1122 
1123         ASSERT3U(ds->ds_phys->ds_prev_snap_txg, <, tx->tx_txg);
1124         ds->ds_phys->ds_prev_snap_obj = dsobj;
1125         ds->ds_phys->ds_prev_snap_txg = crtxg;
1126         ds->ds_phys->ds_unique_bytes = 0;
1127         if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1128                 ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1129 
1130         VERIFY0(zap_add(mos, ds->ds_phys->ds_snapnames_zapobj,
1131             snapname, 8, 1, &dsobj, tx));
1132 
1133         if (ds->ds_prev)
1134                 dsl_dataset_rele(ds->ds_prev, ds);
1135         VERIFY0(dsl_dataset_hold_obj(dp,
1136             ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev));
1137 
1138         dsl_scan_ds_snapshotted(ds, tx);
1139 
1140         dsl_dir_snap_cmtime_update(ds->ds_dir);
1141 
1142         spa_history_log_internal_ds(ds->ds_prev, "snapshot", tx, "");
1143 }
1144 
1145 static void
1146 dsl_dataset_snapshot_sync(void *arg, dmu_tx_t *tx)
1147 {
1148         dsl_dataset_snapshot_arg_t *ddsa = arg;
1149         dsl_pool_t *dp = dmu_tx_pool(tx);
1150         nvpair_t *pair;
1151 
1152         for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1153             pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1154                 dsl_dataset_t *ds;
1155                 char *name, *atp;
1156                 char dsname[MAXNAMELEN];
1157 
1158                 name = nvpair_name(pair);
1159                 atp = strchr(name, '@');
1160                 (void) strlcpy(dsname, name, atp - name + 1);
1161                 VERIFY0(dsl_dataset_hold(dp, dsname, FTAG, &ds));
1162 
1163                 dsl_dataset_snapshot_sync_impl(ds, atp + 1, tx);
1164                 if (ddsa->ddsa_props != NULL) {
1165                         dsl_props_set_sync_impl(ds->ds_prev,
1166                             ZPROP_SRC_LOCAL, ddsa->ddsa_props, tx);
1167                 }
1168                 dsl_dataset_rele(ds, FTAG);
1169         }
1170 }
1171 
1172 /*
1173  * The snapshots must all be in the same pool.
1174  * All-or-nothing: if there are any failures, nothing will be modified.
1175  */
1176 int
1177 dsl_dataset_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t *errors)
1178 {
1179         dsl_dataset_snapshot_arg_t ddsa;
1180         nvpair_t *pair;
1181         boolean_t needsuspend;
1182         int error;
1183         spa_t *spa;
1184         char *firstname;
1185         nvlist_t *suspended = NULL;
1186 
1187         pair = nvlist_next_nvpair(snaps, NULL);
1188         if (pair == NULL)
1189                 return (0);
1190         firstname = nvpair_name(pair);
1191 
1192         error = spa_open(firstname, &spa, FTAG);
1193         if (error != 0)
1194                 return (error);
1195         needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1196         spa_close(spa, FTAG);
1197 
1198         if (needsuspend) {
1199                 suspended = fnvlist_alloc();
1200                 for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
1201                     pair = nvlist_next_nvpair(snaps, pair)) {
1202                         char fsname[MAXNAMELEN];
1203                         char *snapname = nvpair_name(pair);
1204                         char *atp;
1205                         void *cookie;
1206 
1207                         atp = strchr(snapname, '@');
1208                         if (atp == NULL) {
1209                                 error = SET_ERROR(EINVAL);
1210                                 break;
1211                         }
1212                         (void) strlcpy(fsname, snapname, atp - snapname + 1);
1213 
1214                         error = zil_suspend(fsname, &cookie);
1215                         if (error != 0)
1216                                 break;
1217                         fnvlist_add_uint64(suspended, fsname,
1218                             (uintptr_t)cookie);
1219                 }
1220         }
1221 
1222         ddsa.ddsa_snaps = snaps;
1223         ddsa.ddsa_props = props;
1224         ddsa.ddsa_errors = errors;
1225 
1226         if (error == 0) {
1227                 error = dsl_sync_task(firstname, dsl_dataset_snapshot_check,
1228                     dsl_dataset_snapshot_sync, &ddsa,
1229                     fnvlist_num_pairs(snaps) * 3);
1230         }
1231 
1232         if (suspended != NULL) {
1233                 for (pair = nvlist_next_nvpair(suspended, NULL); pair != NULL;
1234                     pair = nvlist_next_nvpair(suspended, pair)) {
1235                         zil_resume((void *)(uintptr_t)
1236                             fnvpair_value_uint64(pair));
1237                 }
1238                 fnvlist_free(suspended);
1239         }
1240 
1241         return (error);
1242 }
1243 
1244 typedef struct dsl_dataset_snapshot_tmp_arg {
1245         const char *ddsta_fsname;
1246         const char *ddsta_snapname;
1247         minor_t ddsta_cleanup_minor;
1248         const char *ddsta_htag;
1249 } dsl_dataset_snapshot_tmp_arg_t;
1250 
1251 static int
1252 dsl_dataset_snapshot_tmp_check(void *arg, dmu_tx_t *tx)
1253 {
1254         dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1255         dsl_pool_t *dp = dmu_tx_pool(tx);
1256         dsl_dataset_t *ds;
1257         int error;
1258 
1259         error = dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds);
1260         if (error != 0)
1261                 return (error);
1262 
1263         error = dsl_dataset_snapshot_check_impl(ds, ddsta->ddsta_snapname, tx);
1264         if (error != 0) {
1265                 dsl_dataset_rele(ds, FTAG);
1266                 return (error);
1267         }
1268 
1269         if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS) {
1270                 dsl_dataset_rele(ds, FTAG);
1271                 return (SET_ERROR(ENOTSUP));
1272         }
1273         error = dsl_dataset_user_hold_check_one(NULL, ddsta->ddsta_htag,
1274             B_TRUE, tx);
1275         if (error != 0) {
1276                 dsl_dataset_rele(ds, FTAG);
1277                 return (error);
1278         }
1279 
1280         dsl_dataset_rele(ds, FTAG);
1281         return (0);
1282 }
1283 
1284 static void
1285 dsl_dataset_snapshot_tmp_sync(void *arg, dmu_tx_t *tx)
1286 {
1287         dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1288         dsl_pool_t *dp = dmu_tx_pool(tx);
1289         dsl_dataset_t *ds;
1290 
1291         VERIFY0(dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds));
1292 
1293         dsl_dataset_snapshot_sync_impl(ds, ddsta->ddsta_snapname, tx);
1294         dsl_dataset_user_hold_sync_one(ds->ds_prev, ddsta->ddsta_htag,
1295             ddsta->ddsta_cleanup_minor, gethrestime_sec(), tx);
1296         dsl_destroy_snapshot_sync_impl(ds->ds_prev, B_TRUE, tx);
1297 
1298         dsl_dataset_rele(ds, FTAG);
1299 }
1300 
1301 int
1302 dsl_dataset_snapshot_tmp(const char *fsname, const char *snapname,
1303     minor_t cleanup_minor, const char *htag)
1304 {
1305         dsl_dataset_snapshot_tmp_arg_t ddsta;
1306         int error;
1307         spa_t *spa;
1308         boolean_t needsuspend;
1309         void *cookie;
1310 
1311         ddsta.ddsta_fsname = fsname;
1312         ddsta.ddsta_snapname = snapname;
1313         ddsta.ddsta_cleanup_minor = cleanup_minor;
1314         ddsta.ddsta_htag = htag;
1315 
1316         error = spa_open(fsname, &spa, FTAG);
1317         if (error != 0)
1318                 return (error);
1319         needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1320         spa_close(spa, FTAG);
1321 
1322         if (needsuspend) {
1323                 error = zil_suspend(fsname, &cookie);
1324                 if (error != 0)
1325                         return (error);
1326         }
1327 
1328         error = dsl_sync_task(fsname, dsl_dataset_snapshot_tmp_check,
1329             dsl_dataset_snapshot_tmp_sync, &ddsta, 3);
1330 
1331         if (needsuspend)
1332                 zil_resume(cookie);
1333         return (error);
1334 }
1335 
1336 
1337 void
1338 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
1339 {
1340         ASSERT(dmu_tx_is_syncing(tx));
1341         ASSERT(ds->ds_objset != NULL);
1342         ASSERT(ds->ds_phys->ds_next_snap_obj == 0);
1343 
1344         /*
1345          * in case we had to change ds_fsid_guid when we opened it,
1346          * sync it out now.
1347          */
1348         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1349         ds->ds_phys->ds_fsid_guid = ds->ds_fsid_guid;
1350 
1351         dmu_objset_sync(ds->ds_objset, zio, tx);
1352 }
1353 
1354 static void
1355 get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
1356 {
1357         uint64_t count = 0;
1358         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1359         zap_cursor_t zc;
1360         zap_attribute_t za;
1361         nvlist_t *propval = fnvlist_alloc();
1362         nvlist_t *val = fnvlist_alloc();
1363 
1364         ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
1365 
1366         /*
1367          * There may be missing entries in ds_next_clones_obj
1368          * due to a bug in a previous version of the code.
1369          * Only trust it if it has the right number of entries.
1370          */
1371         if (ds->ds_phys->ds_next_clones_obj != 0) {
1372                 ASSERT0(zap_count(mos, ds->ds_phys->ds_next_clones_obj,
1373                     &count));
1374         }
1375         if (count != ds->ds_phys->ds_num_children - 1)
1376                 goto fail;
1377         for (zap_cursor_init(&zc, mos, ds->ds_phys->ds_next_clones_obj);
1378             zap_cursor_retrieve(&zc, &za) == 0;
1379             zap_cursor_advance(&zc)) {
1380                 dsl_dataset_t *clone;
1381                 char buf[ZFS_MAXNAMELEN];
1382                 VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
1383                     za.za_first_integer, FTAG, &clone));
1384                 dsl_dir_name(clone->ds_dir, buf);
1385                 fnvlist_add_boolean(val, buf);
1386                 dsl_dataset_rele(clone, FTAG);
1387         }
1388         zap_cursor_fini(&zc);
1389         fnvlist_add_nvlist(propval, ZPROP_VALUE, val);
1390         fnvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES), propval);
1391 fail:
1392         nvlist_free(val);
1393         nvlist_free(propval);
1394 }
1395 
1396 void
1397 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
1398 {
1399         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1400         uint64_t refd, avail, uobjs, aobjs, ratio;
1401 
1402         ASSERT(dsl_pool_config_held(dp));
1403 
1404         ratio = ds->ds_phys->ds_compressed_bytes == 0 ? 100 :
1405             (ds->ds_phys->ds_uncompressed_bytes * 100 /
1406             ds->ds_phys->ds_compressed_bytes);
1407 
1408         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRATIO, ratio);
1409         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALREFERENCED,
1410             ds->ds_phys->ds_uncompressed_bytes);
1411 
1412         if (dsl_dataset_is_snapshot(ds)) {
1413                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
1414                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
1415                     ds->ds_phys->ds_unique_bytes);
1416                 get_clones_stat(ds, nv);
1417         } else {
1418                 dsl_dir_stats(ds->ds_dir, nv);
1419         }
1420 
1421         dsl_dataset_space(ds, &refd, &avail, &uobjs, &aobjs);
1422         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE, avail);
1423         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED, refd);
1424 
1425         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION,
1426             ds->ds_phys->ds_creation_time);
1427         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG,
1428             ds->ds_phys->ds_creation_txg);
1429         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA,
1430             ds->ds_quota);
1431         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION,
1432             ds->ds_reserved);
1433         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_GUID,
1434             ds->ds_phys->ds_guid);
1435         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_UNIQUE,
1436             ds->ds_phys->ds_unique_bytes);
1437         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_OBJSETID,
1438             ds->ds_object);
1439         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERREFS,
1440             ds->ds_userrefs);
1441         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
1442             DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
1443 
1444         if (ds->ds_phys->ds_prev_snap_obj != 0) {
1445                 uint64_t written, comp, uncomp;
1446                 dsl_pool_t *dp = ds->ds_dir->dd_pool;
1447                 dsl_dataset_t *prev;
1448 
1449                 int err = dsl_dataset_hold_obj(dp,
1450                     ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
1451                 if (err == 0) {
1452                         err = dsl_dataset_space_written(prev, ds, &written,
1453                             &comp, &uncomp);
1454                         dsl_dataset_rele(prev, FTAG);
1455                         if (err == 0) {
1456                                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
1457                                     written);
1458                         }
1459                 }
1460         }
1461 }
1462 
1463 void
1464 dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat)
1465 {
1466         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1467         ASSERT(dsl_pool_config_held(dp));
1468 
1469         stat->dds_creation_txg = ds->ds_phys->ds_creation_txg;
1470         stat->dds_inconsistent = ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT;
1471         stat->dds_guid = ds->ds_phys->ds_guid;
1472         stat->dds_origin[0] = '\0';
1473         if (dsl_dataset_is_snapshot(ds)) {
1474                 stat->dds_is_snapshot = B_TRUE;
1475                 stat->dds_num_clones = ds->ds_phys->ds_num_children - 1;
1476         } else {
1477                 stat->dds_is_snapshot = B_FALSE;
1478                 stat->dds_num_clones = 0;
1479 
1480                 if (dsl_dir_is_clone(ds->ds_dir)) {
1481                         dsl_dataset_t *ods;
1482 
1483                         VERIFY0(dsl_dataset_hold_obj(dp,
1484                             ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &ods));
1485                         dsl_dataset_name(ods, stat->dds_origin);
1486                         dsl_dataset_rele(ods, FTAG);
1487                 }
1488         }
1489 }
1490 
1491 uint64_t
1492 dsl_dataset_fsid_guid(dsl_dataset_t *ds)
1493 {
1494         return (ds->ds_fsid_guid);
1495 }
1496 
1497 void
1498 dsl_dataset_space(dsl_dataset_t *ds,
1499     uint64_t *refdbytesp, uint64_t *availbytesp,
1500     uint64_t *usedobjsp, uint64_t *availobjsp)
1501 {
1502         *refdbytesp = ds->ds_phys->ds_referenced_bytes;
1503         *availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE);
1504         if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes)
1505                 *availbytesp += ds->ds_reserved - ds->ds_phys->ds_unique_bytes;
1506         if (ds->ds_quota != 0) {
1507                 /*
1508                  * Adjust available bytes according to refquota
1509                  */
1510                 if (*refdbytesp < ds->ds_quota)
1511                         *availbytesp = MIN(*availbytesp,
1512                             ds->ds_quota - *refdbytesp);
1513                 else
1514                         *availbytesp = 0;
1515         }
1516         *usedobjsp = ds->ds_phys->ds_bp.blk_fill;
1517         *availobjsp = DN_MAX_OBJECT - *usedobjsp;
1518 }
1519 
1520 boolean_t
1521 dsl_dataset_modified_since_lastsnap(dsl_dataset_t *ds)
1522 {
1523         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1524 
1525         ASSERT(dsl_pool_config_held(dp));
1526         if (ds->ds_prev == NULL)
1527                 return (B_FALSE);
1528         if (ds->ds_phys->ds_bp.blk_birth >
1529             ds->ds_prev->ds_phys->ds_creation_txg) {
1530                 objset_t *os, *os_prev;
1531                 /*
1532                  * It may be that only the ZIL differs, because it was
1533                  * reset in the head.  Don't count that as being
1534                  * modified.
1535                  */
1536                 if (dmu_objset_from_ds(ds, &os) != 0)
1537                         return (B_TRUE);
1538                 if (dmu_objset_from_ds(ds->ds_prev, &os_prev) != 0)
1539                         return (B_TRUE);
1540                 return (bcmp(&os->os_phys->os_meta_dnode,
1541                     &os_prev->os_phys->os_meta_dnode,
1542                     sizeof (os->os_phys->os_meta_dnode)) != 0);
1543         }
1544         return (B_FALSE);
1545 }
1546 
1547 typedef struct dsl_dataset_rename_snapshot_arg {
1548         const char *ddrsa_fsname;
1549         const char *ddrsa_oldsnapname;
1550         const char *ddrsa_newsnapname;
1551         boolean_t ddrsa_recursive;
1552         dmu_tx_t *ddrsa_tx;
1553 } dsl_dataset_rename_snapshot_arg_t;
1554 
1555 /* ARGSUSED */
1556 static int
1557 dsl_dataset_rename_snapshot_check_impl(dsl_pool_t *dp,
1558     dsl_dataset_t *hds, void *arg)
1559 {
1560         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1561         int error;
1562         uint64_t val;
1563 
1564         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
1565         if (error != 0) {
1566                 /* ignore nonexistent snapshots */
1567                 return (error == ENOENT ? 0 : error);
1568         }
1569 
1570         /* new name should not exist */
1571         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_newsnapname, &val);
1572         if (error == 0)
1573                 error = SET_ERROR(EEXIST);
1574         else if (error == ENOENT)
1575                 error = 0;
1576 
1577         /* dataset name + 1 for the "@" + the new snapshot name must fit */
1578         if (dsl_dir_namelen(hds->ds_dir) + 1 +
1579             strlen(ddrsa->ddrsa_newsnapname) >= MAXNAMELEN)
1580                 error = SET_ERROR(ENAMETOOLONG);
1581 
1582         return (error);
1583 }
1584 
1585 static int
1586 dsl_dataset_rename_snapshot_check(void *arg, dmu_tx_t *tx)
1587 {
1588         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1589         dsl_pool_t *dp = dmu_tx_pool(tx);
1590         dsl_dataset_t *hds;
1591         int error;
1592 
1593         error = dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds);
1594         if (error != 0)
1595                 return (error);
1596 
1597         if (ddrsa->ddrsa_recursive) {
1598                 error = dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
1599                     dsl_dataset_rename_snapshot_check_impl, ddrsa,
1600                     DS_FIND_CHILDREN);
1601         } else {
1602                 error = dsl_dataset_rename_snapshot_check_impl(dp, hds, ddrsa);
1603         }
1604         dsl_dataset_rele(hds, FTAG);
1605         return (error);
1606 }
1607 
1608 static int
1609 dsl_dataset_rename_snapshot_sync_impl(dsl_pool_t *dp,
1610     dsl_dataset_t *hds, void *arg)
1611 {
1612         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1613         dsl_dataset_t *ds;
1614         uint64_t val;
1615         dmu_tx_t *tx = ddrsa->ddrsa_tx;
1616         int error;
1617 
1618         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
1619         ASSERT(error == 0 || error == ENOENT);
1620         if (error == ENOENT) {
1621                 /* ignore nonexistent snapshots */
1622                 return (0);
1623         }
1624 
1625         VERIFY0(dsl_dataset_hold_obj(dp, val, FTAG, &ds));
1626 
1627         /* log before we change the name */
1628         spa_history_log_internal_ds(ds, "rename", tx,
1629             "-> @%s", ddrsa->ddrsa_newsnapname);
1630 
1631         VERIFY0(dsl_dataset_snap_remove(hds, ddrsa->ddrsa_oldsnapname, tx));
1632         mutex_enter(&ds->ds_lock);
1633         (void) strcpy(ds->ds_snapname, ddrsa->ddrsa_newsnapname);
1634         mutex_exit(&ds->ds_lock);
1635         VERIFY0(zap_add(dp->dp_meta_objset, hds->ds_phys->ds_snapnames_zapobj,
1636             ds->ds_snapname, 8, 1, &ds->ds_object, tx));
1637 
1638         dsl_dataset_rele(ds, FTAG);
1639         return (0);
1640 }
1641 
1642 static void
1643 dsl_dataset_rename_snapshot_sync(void *arg, dmu_tx_t *tx)
1644 {
1645         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1646         dsl_pool_t *dp = dmu_tx_pool(tx);
1647         dsl_dataset_t *hds;
1648 
1649         VERIFY0(dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds));
1650         ddrsa->ddrsa_tx = tx;
1651         if (ddrsa->ddrsa_recursive) {
1652                 VERIFY0(dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
1653                     dsl_dataset_rename_snapshot_sync_impl, ddrsa,
1654                     DS_FIND_CHILDREN));
1655         } else {
1656                 VERIFY0(dsl_dataset_rename_snapshot_sync_impl(dp, hds, ddrsa));
1657         }
1658         dsl_dataset_rele(hds, FTAG);
1659 }
1660 
1661 int
1662 dsl_dataset_rename_snapshot(const char *fsname,
1663     const char *oldsnapname, const char *newsnapname, boolean_t recursive)
1664 {
1665         dsl_dataset_rename_snapshot_arg_t ddrsa;
1666 
1667         ddrsa.ddrsa_fsname = fsname;
1668         ddrsa.ddrsa_oldsnapname = oldsnapname;
1669         ddrsa.ddrsa_newsnapname = newsnapname;
1670         ddrsa.ddrsa_recursive = recursive;
1671 
1672         return (dsl_sync_task(fsname, dsl_dataset_rename_snapshot_check,
1673             dsl_dataset_rename_snapshot_sync, &ddrsa, 1));
1674 }
1675 
1676 static int
1677 dsl_dataset_rollback_check(void *arg, dmu_tx_t *tx)
1678 {
1679         const char *fsname = arg;
1680         dsl_pool_t *dp = dmu_tx_pool(tx);
1681         dsl_dataset_t *ds;
1682         int64_t unused_refres_delta;
1683         int error;
1684 
1685         error = dsl_dataset_hold(dp, fsname, FTAG, &ds);
1686         if (error != 0)
1687                 return (error);
1688 
1689         /* must not be a snapshot */
1690         if (dsl_dataset_is_snapshot(ds)) {
1691                 dsl_dataset_rele(ds, FTAG);
1692                 return (SET_ERROR(EINVAL));
1693         }
1694 
1695         /* must have a most recent snapshot */
1696         if (ds->ds_phys->ds_prev_snap_txg < TXG_INITIAL) {
1697                 dsl_dataset_rele(ds, FTAG);
1698                 return (SET_ERROR(EINVAL));
1699         }
1700 
1701         if (dsl_dataset_long_held(ds)) {
1702                 dsl_dataset_rele(ds, FTAG);
1703                 return (SET_ERROR(EBUSY));
1704         }
1705 
1706         /*
1707          * Check if the snap we are rolling back to uses more than
1708          * the refquota.
1709          */
1710         if (ds->ds_quota != 0 &&
1711             ds->ds_prev->ds_phys->ds_referenced_bytes > ds->ds_quota) {
1712                 dsl_dataset_rele(ds, FTAG);
1713                 return (SET_ERROR(EDQUOT));
1714         }
1715 
1716         /*
1717          * When we do the clone swap, we will temporarily use more space
1718          * due to the refreservation (the head will no longer have any
1719          * unique space, so the entire amount of the refreservation will need
1720          * to be free).  We will immediately destroy the clone, freeing
1721          * this space, but the freeing happens over many txg's.
1722          */
1723         unused_refres_delta = (int64_t)MIN(ds->ds_reserved,
1724             ds->ds_phys->ds_unique_bytes);
1725 
1726         if (unused_refres_delta > 0 &&
1727             unused_refres_delta >
1728             dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) {
1729                 dsl_dataset_rele(ds, FTAG);
1730                 return (SET_ERROR(ENOSPC));
1731         }
1732 
1733         dsl_dataset_rele(ds, FTAG);
1734         return (0);
1735 }
1736 
1737 static void
1738 dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
1739 {
1740         const char *fsname = arg;
1741         dsl_pool_t *dp = dmu_tx_pool(tx);
1742         dsl_dataset_t *ds, *clone;
1743         uint64_t cloneobj;
1744 
1745         VERIFY0(dsl_dataset_hold(dp, fsname, FTAG, &ds));
1746 
1747         cloneobj = dsl_dataset_create_sync(ds->ds_dir, "%rollback",
1748             ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, tx);
1749 
1750         VERIFY0(dsl_dataset_hold_obj(dp, cloneobj, FTAG, &clone));
1751 
1752         dsl_dataset_clone_swap_sync_impl(clone, ds, tx);
1753         dsl_dataset_zero_zil(ds, tx);
1754 
1755         dsl_destroy_head_sync_impl(clone, tx);
1756 
1757         dsl_dataset_rele(clone, FTAG);
1758         dsl_dataset_rele(ds, FTAG);
1759 }
1760 
1761 int
1762 dsl_dataset_rollback(const char *fsname)
1763 {
1764         return (dsl_sync_task(fsname, dsl_dataset_rollback_check,
1765             dsl_dataset_rollback_sync, (void *)fsname, 1));
1766 }
1767 
1768 struct promotenode {
1769         list_node_t link;
1770         dsl_dataset_t *ds;
1771 };
1772 
1773 typedef struct dsl_dataset_promote_arg {
1774         const char *ddpa_clonename;
1775         dsl_dataset_t *ddpa_clone;
1776         list_t shared_snaps, origin_snaps, clone_snaps;
1777         dsl_dataset_t *origin_origin; /* origin of the origin */
1778         uint64_t used, comp, uncomp, unique, cloneusedsnap, originusedsnap;
1779         char *err_ds;
1780 } dsl_dataset_promote_arg_t;
1781 
1782 static int snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep);
1783 static int promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp,
1784     void *tag);
1785 static void promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag);
1786 
1787 static int
1788 dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
1789 {
1790         dsl_dataset_promote_arg_t *ddpa = arg;
1791         dsl_pool_t *dp = dmu_tx_pool(tx);
1792         dsl_dataset_t *hds;
1793         struct promotenode *snap;
1794         dsl_dataset_t *origin_ds;
1795         int err;
1796         uint64_t unused;
1797 
1798         err = promote_hold(ddpa, dp, FTAG);
1799         if (err != 0)
1800                 return (err);
1801 
1802         hds = ddpa->ddpa_clone;
1803 
1804         if (hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE) {
1805                 promote_rele(ddpa, FTAG);
1806                 return (SET_ERROR(EXDEV));
1807         }
1808 
1809         /*
1810          * Compute and check the amount of space to transfer.  Since this is
1811          * so expensive, don't do the preliminary check.
1812          */
1813         if (!dmu_tx_is_syncing(tx)) {
1814                 promote_rele(ddpa, FTAG);
1815                 return (0);
1816         }
1817 
1818         snap = list_head(&ddpa->shared_snaps);
1819         origin_ds = snap->ds;
1820 
1821         /* compute origin's new unique space */
1822         snap = list_tail(&ddpa->clone_snaps);
1823         ASSERT3U(snap->ds->ds_phys->ds_prev_snap_obj, ==, origin_ds->ds_object);
1824         dsl_deadlist_space_range(&snap->ds->ds_deadlist,
1825             origin_ds->ds_phys->ds_prev_snap_txg, UINT64_MAX,
1826             &ddpa->unique, &unused, &unused);
1827 
1828         /*
1829          * Walk the snapshots that we are moving
1830          *
1831          * Compute space to transfer.  Consider the incremental changes
1832          * to used by each snapshot:
1833          * (my used) = (prev's used) + (blocks born) - (blocks killed)
1834          * So each snapshot gave birth to:
1835          * (blocks born) = (my used) - (prev's used) + (blocks killed)
1836          * So a sequence would look like:
1837          * (uN - u(N-1) + kN) + ... + (u1 - u0 + k1) + (u0 - 0 + k0)
1838          * Which simplifies to:
1839          * uN + kN + kN-1 + ... + k1 + k0
1840          * Note however, if we stop before we reach the ORIGIN we get:
1841          * uN + kN + kN-1 + ... + kM - uM-1
1842          */
1843         ddpa->used = origin_ds->ds_phys->ds_referenced_bytes;
1844         ddpa->comp = origin_ds->ds_phys->ds_compressed_bytes;
1845         ddpa->uncomp = origin_ds->ds_phys->ds_uncompressed_bytes;
1846         for (snap = list_head(&ddpa->shared_snaps); snap;
1847             snap = list_next(&ddpa->shared_snaps, snap)) {
1848                 uint64_t val, dlused, dlcomp, dluncomp;
1849                 dsl_dataset_t *ds = snap->ds;
1850 
1851                 /*
1852                  * If there are long holds, we won't be able to evict
1853                  * the objset.
1854                  */
1855                 if (dsl_dataset_long_held(ds)) {
1856                         err = SET_ERROR(EBUSY);
1857                         goto out;
1858                 }
1859 
1860                 /* Check that the snapshot name does not conflict */
1861                 VERIFY0(dsl_dataset_get_snapname(ds));
1862                 err = dsl_dataset_snap_lookup(hds, ds->ds_snapname, &val);
1863                 if (err == 0) {
1864                         (void) strcpy(ddpa->err_ds, snap->ds->ds_snapname);
1865                         err = SET_ERROR(EEXIST);
1866                         goto out;
1867                 }
1868                 if (err != ENOENT)
1869                         goto out;
1870 
1871                 /* The very first snapshot does not have a deadlist */
1872                 if (ds->ds_phys->ds_prev_snap_obj == 0)
1873                         continue;
1874 
1875                 dsl_deadlist_space(&ds->ds_deadlist,
1876                     &dlused, &dlcomp, &dluncomp);
1877                 ddpa->used += dlused;
1878                 ddpa->comp += dlcomp;
1879                 ddpa->uncomp += dluncomp;
1880         }
1881 
1882         /*
1883          * If we are a clone of a clone then we never reached ORIGIN,
1884          * so we need to subtract out the clone origin's used space.
1885          */
1886         if (ddpa->origin_origin) {
1887                 ddpa->used -= ddpa->origin_origin->ds_phys->ds_referenced_bytes;
1888                 ddpa->comp -= ddpa->origin_origin->ds_phys->ds_compressed_bytes;
1889                 ddpa->uncomp -=
1890                     ddpa->origin_origin->ds_phys->ds_uncompressed_bytes;
1891         }
1892 
1893         /* Check that there is enough space here */
1894         err = dsl_dir_transfer_possible(origin_ds->ds_dir, hds->ds_dir,
1895             ddpa->used);
1896         if (err != 0)
1897                 goto out;
1898 
1899         /*
1900          * Compute the amounts of space that will be used by snapshots
1901          * after the promotion (for both origin and clone).  For each,
1902          * it is the amount of space that will be on all of their
1903          * deadlists (that was not born before their new origin).
1904          */
1905         if (hds->ds_dir->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
1906                 uint64_t space;
1907 
1908                 /*
1909                  * Note, typically this will not be a clone of a clone,
1910                  * so dd_origin_txg will be < TXG_INITIAL, so
1911                  * these snaplist_space() -> dsl_deadlist_space_range()
1912                  * calls will be fast because they do not have to
1913                  * iterate over all bps.
1914                  */
1915                 snap = list_head(&ddpa->origin_snaps);
1916                 err = snaplist_space(&ddpa->shared_snaps,
1917                     snap->ds->ds_dir->dd_origin_txg, &ddpa->cloneusedsnap);
1918                 if (err != 0)
1919                         goto out;
1920 
1921                 err = snaplist_space(&ddpa->clone_snaps,
1922                     snap->ds->ds_dir->dd_origin_txg, &space);
1923                 if (err != 0)
1924                         goto out;
1925                 ddpa->cloneusedsnap += space;
1926         }
1927         if (origin_ds->ds_dir->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
1928                 err = snaplist_space(&ddpa->origin_snaps,
1929                     origin_ds->ds_phys->ds_creation_txg, &ddpa->originusedsnap);
1930                 if (err != 0)
1931                         goto out;
1932         }
1933 
1934 out:
1935         promote_rele(ddpa, FTAG);
1936         return (err);
1937 }
1938 
1939 static void
1940 dsl_dataset_promote_sync(void *arg, dmu_tx_t *tx)
1941 {
1942         dsl_dataset_promote_arg_t *ddpa = arg;
1943         dsl_pool_t *dp = dmu_tx_pool(tx);
1944         dsl_dataset_t *hds;
1945         struct promotenode *snap;
1946         dsl_dataset_t *origin_ds;
1947         dsl_dataset_t *origin_head;
1948         dsl_dir_t *dd;
1949         dsl_dir_t *odd = NULL;
1950         uint64_t oldnext_obj;
1951         int64_t delta;
1952 
1953         VERIFY0(promote_hold(ddpa, dp, FTAG));
1954         hds = ddpa->ddpa_clone;
1955 
1956         ASSERT0(hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE);
1957 
1958         snap = list_head(&ddpa->shared_snaps);
1959         origin_ds = snap->ds;
1960         dd = hds->ds_dir;
1961 
1962         snap = list_head(&ddpa->origin_snaps);
1963         origin_head = snap->ds;
1964 
1965         /*
1966          * We need to explicitly open odd, since origin_ds's dd will be
1967          * changing.
1968          */
1969         VERIFY0(dsl_dir_hold_obj(dp, origin_ds->ds_dir->dd_object,
1970             NULL, FTAG, &odd));
1971 
1972         /* change origin's next snap */
1973         dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
1974         oldnext_obj = origin_ds->ds_phys->ds_next_snap_obj;
1975         snap = list_tail(&ddpa->clone_snaps);
1976         ASSERT3U(snap->ds->ds_phys->ds_prev_snap_obj, ==, origin_ds->ds_object);
1977         origin_ds->ds_phys->ds_next_snap_obj = snap->ds->ds_object;
1978 
1979         /* change the origin's next clone */
1980         if (origin_ds->ds_phys->ds_next_clones_obj) {
1981                 dsl_dataset_remove_from_next_clones(origin_ds,
1982                     snap->ds->ds_object, tx);
1983                 VERIFY0(zap_add_int(dp->dp_meta_objset,
1984                     origin_ds->ds_phys->ds_next_clones_obj,
1985                     oldnext_obj, tx));
1986         }
1987 
1988         /* change origin */
1989         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1990         ASSERT3U(dd->dd_phys->dd_origin_obj, ==, origin_ds->ds_object);
1991         dd->dd_phys->dd_origin_obj = odd->dd_phys->dd_origin_obj;
1992         dd->dd_origin_txg = origin_head->ds_dir->dd_origin_txg;
1993         dmu_buf_will_dirty(odd->dd_dbuf, tx);
1994         odd->dd_phys->dd_origin_obj = origin_ds->ds_object;
1995         origin_head->ds_dir->dd_origin_txg =
1996             origin_ds->ds_phys->ds_creation_txg;
1997 
1998         /* change dd_clone entries */
1999         if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2000                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2001                     odd->dd_phys->dd_clones, hds->ds_object, tx));
2002                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2003                     ddpa->origin_origin->ds_dir->dd_phys->dd_clones,
2004                     hds->ds_object, tx));
2005 
2006                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2007                     ddpa->origin_origin->ds_dir->dd_phys->dd_clones,
2008                     origin_head->ds_object, tx));
2009                 if (dd->dd_phys->dd_clones == 0) {
2010                         dd->dd_phys->dd_clones = zap_create(dp->dp_meta_objset,
2011                             DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
2012                 }
2013                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2014                     dd->dd_phys->dd_clones, origin_head->ds_object, tx));
2015         }
2016 
2017         /* move snapshots to this dir */
2018         for (snap = list_head(&ddpa->shared_snaps); snap;
2019             snap = list_next(&ddpa->shared_snaps, snap)) {
2020                 dsl_dataset_t *ds = snap->ds;
2021 
2022                 /*
2023                  * Property callbacks are registered to a particular
2024                  * dsl_dir.  Since ours is changing, evict the objset
2025                  * so that they will be unregistered from the old dsl_dir.
2026                  */
2027                 if (ds->ds_objset) {
2028                         dmu_objset_evict(ds->ds_objset);
2029                         ds->ds_objset = NULL;
2030                 }
2031 
2032                 /* move snap name entry */
2033                 VERIFY0(dsl_dataset_get_snapname(ds));
2034                 VERIFY0(dsl_dataset_snap_remove(origin_head,
2035                     ds->ds_snapname, tx));
2036                 VERIFY0(zap_add(dp->dp_meta_objset,
2037                     hds->ds_phys->ds_snapnames_zapobj, ds->ds_snapname,
2038                     8, 1, &ds->ds_object, tx));
2039 
2040                 /* change containing dsl_dir */
2041                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
2042                 ASSERT3U(ds->ds_phys->ds_dir_obj, ==, odd->dd_object);
2043                 ds->ds_phys->ds_dir_obj = dd->dd_object;
2044                 ASSERT3P(ds->ds_dir, ==, odd);
2045                 dsl_dir_rele(ds->ds_dir, ds);
2046                 VERIFY0(dsl_dir_hold_obj(dp, dd->dd_object,
2047                     NULL, ds, &ds->ds_dir));
2048 
2049                 /* move any clone references */
2050                 if (ds->ds_phys->ds_next_clones_obj &&
2051                     spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2052                         zap_cursor_t zc;
2053                         zap_attribute_t za;
2054 
2055                         for (zap_cursor_init(&zc, dp->dp_meta_objset,
2056                             ds->ds_phys->ds_next_clones_obj);
2057                             zap_cursor_retrieve(&zc, &za) == 0;
2058                             zap_cursor_advance(&zc)) {
2059                                 dsl_dataset_t *cnds;
2060                                 uint64_t o;
2061 
2062                                 if (za.za_first_integer == oldnext_obj) {
2063                                         /*
2064                                          * We've already moved the
2065                                          * origin's reference.
2066                                          */
2067                                         continue;
2068                                 }
2069 
2070                                 VERIFY0(dsl_dataset_hold_obj(dp,
2071                                     za.za_first_integer, FTAG, &cnds));
2072                                 o = cnds->ds_dir->dd_phys->dd_head_dataset_obj;
2073 
2074                                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2075                                     odd->dd_phys->dd_clones, o, tx));
2076                                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2077                                     dd->dd_phys->dd_clones, o, tx));
2078                                 dsl_dataset_rele(cnds, FTAG);
2079                         }
2080                         zap_cursor_fini(&zc);
2081                 }
2082 
2083                 ASSERT(!dsl_prop_hascb(ds));
2084         }
2085 
2086         /*
2087          * Change space accounting.
2088          * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either
2089          * both be valid, or both be 0 (resulting in delta == 0).  This
2090          * is true for each of {clone,origin} independently.
2091          */
2092 
2093         delta = ddpa->cloneusedsnap -
2094             dd->dd_phys->dd_used_breakdown[DD_USED_SNAP];
2095         ASSERT3S(delta, >=, 0);
2096         ASSERT3U(ddpa->used, >=, delta);
2097         dsl_dir_diduse_space(dd, DD_USED_SNAP, delta, 0, 0, tx);
2098         dsl_dir_diduse_space(dd, DD_USED_HEAD,
2099             ddpa->used - delta, ddpa->comp, ddpa->uncomp, tx);
2100 
2101         delta = ddpa->originusedsnap -
2102             odd->dd_phys->dd_used_breakdown[DD_USED_SNAP];
2103         ASSERT3S(delta, <=, 0);
2104         ASSERT3U(ddpa->used, >=, -delta);
2105         dsl_dir_diduse_space(odd, DD_USED_SNAP, delta, 0, 0, tx);
2106         dsl_dir_diduse_space(odd, DD_USED_HEAD,
2107             -ddpa->used - delta, -ddpa->comp, -ddpa->uncomp, tx);
2108 
2109         origin_ds->ds_phys->ds_unique_bytes = ddpa->unique;
2110 
2111         /* log history record */
2112         spa_history_log_internal_ds(hds, "promote", tx, "");
2113 
2114         dsl_dir_rele(odd, FTAG);
2115         promote_rele(ddpa, FTAG);
2116 }
2117 
2118 /*
2119  * Make a list of dsl_dataset_t's for the snapshots between first_obj
2120  * (exclusive) and last_obj (inclusive).  The list will be in reverse
2121  * order (last_obj will be the list_head()).  If first_obj == 0, do all
2122  * snapshots back to this dataset's origin.
2123  */
2124 static int
2125 snaplist_make(dsl_pool_t *dp,
2126     uint64_t first_obj, uint64_t last_obj, list_t *l, void *tag)
2127 {
2128         uint64_t obj = last_obj;
2129 
2130         list_create(l, sizeof (struct promotenode),
2131             offsetof(struct promotenode, link));
2132 
2133         while (obj != first_obj) {
2134                 dsl_dataset_t *ds;
2135                 struct promotenode *snap;
2136                 int err;
2137 
2138                 err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
2139                 ASSERT(err != ENOENT);
2140                 if (err != 0)
2141                         return (err);
2142 
2143                 if (first_obj == 0)
2144                         first_obj = ds->ds_dir->dd_phys->dd_origin_obj;
2145 
2146                 snap = kmem_alloc(sizeof (*snap), KM_SLEEP);
2147                 snap->ds = ds;
2148                 list_insert_tail(l, snap);
2149                 obj = ds->ds_phys->ds_prev_snap_obj;
2150         }
2151 
2152         return (0);
2153 }
2154 
2155 static int
2156 snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep)
2157 {
2158         struct promotenode *snap;
2159 
2160         *spacep = 0;
2161         for (snap = list_head(l); snap; snap = list_next(l, snap)) {
2162                 uint64_t used, comp, uncomp;
2163                 dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2164                     mintxg, UINT64_MAX, &used, &comp, &uncomp);
2165                 *spacep += used;
2166         }
2167         return (0);
2168 }
2169 
2170 static void
2171 snaplist_destroy(list_t *l, void *tag)
2172 {
2173         struct promotenode *snap;
2174 
2175         if (l == NULL || !list_link_active(&l->list_head))
2176                 return;
2177 
2178         while ((snap = list_tail(l)) != NULL) {
2179                 list_remove(l, snap);
2180                 dsl_dataset_rele(snap->ds, tag);
2181                 kmem_free(snap, sizeof (*snap));
2182         }
2183         list_destroy(l);
2184 }
2185 
2186 static int
2187 promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp, void *tag)
2188 {
2189         int error;
2190         dsl_dir_t *dd;
2191         struct promotenode *snap;
2192 
2193         error = dsl_dataset_hold(dp, ddpa->ddpa_clonename, tag,
2194             &ddpa->ddpa_clone);
2195         if (error != 0)
2196                 return (error);
2197         dd = ddpa->ddpa_clone->ds_dir;
2198 
2199         if (dsl_dataset_is_snapshot(ddpa->ddpa_clone) ||
2200             !dsl_dir_is_clone(dd)) {
2201                 dsl_dataset_rele(ddpa->ddpa_clone, tag);
2202                 return (SET_ERROR(EINVAL));
2203         }
2204 
2205         error = snaplist_make(dp, 0, dd->dd_phys->dd_origin_obj,
2206             &ddpa->shared_snaps, tag);
2207         if (error != 0)
2208                 goto out;
2209 
2210         error = snaplist_make(dp, 0, ddpa->ddpa_clone->ds_object,
2211             &ddpa->clone_snaps, tag);
2212         if (error != 0)
2213                 goto out;
2214 
2215         snap = list_head(&ddpa->shared_snaps);
2216         ASSERT3U(snap->ds->ds_object, ==, dd->dd_phys->dd_origin_obj);
2217         error = snaplist_make(dp, dd->dd_phys->dd_origin_obj,
2218             snap->ds->ds_dir->dd_phys->dd_head_dataset_obj,
2219             &ddpa->origin_snaps, tag);
2220         if (error != 0)
2221                 goto out;
2222 
2223         if (snap->ds->ds_dir->dd_phys->dd_origin_obj != 0) {
2224                 error = dsl_dataset_hold_obj(dp,
2225                     snap->ds->ds_dir->dd_phys->dd_origin_obj,
2226                     tag, &ddpa->origin_origin);
2227                 if (error != 0)
2228                         goto out;
2229         }
2230 out:
2231         if (error != 0)
2232                 promote_rele(ddpa, tag);
2233         return (error);
2234 }
2235 
2236 static void
2237 promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag)
2238 {
2239         snaplist_destroy(&ddpa->shared_snaps, tag);
2240         snaplist_destroy(&ddpa->clone_snaps, tag);
2241         snaplist_destroy(&ddpa->origin_snaps, tag);
2242         if (ddpa->origin_origin != NULL)
2243                 dsl_dataset_rele(ddpa->origin_origin, tag);
2244         dsl_dataset_rele(ddpa->ddpa_clone, tag);
2245 }
2246 
2247 /*
2248  * Promote a clone.
2249  *
2250  * If it fails due to a conflicting snapshot name, "conflsnap" will be filled
2251  * in with the name.  (It must be at least MAXNAMELEN bytes long.)
2252  */
2253 int
2254 dsl_dataset_promote(const char *name, char *conflsnap)
2255 {
2256         dsl_dataset_promote_arg_t ddpa = { 0 };
2257         uint64_t numsnaps;
2258         int error;
2259         objset_t *os;
2260 
2261         /*
2262          * We will modify space proportional to the number of
2263          * snapshots.  Compute numsnaps.
2264          */
2265         error = dmu_objset_hold(name, FTAG, &os);
2266         if (error != 0)
2267                 return (error);
2268         error = zap_count(dmu_objset_pool(os)->dp_meta_objset,
2269             dmu_objset_ds(os)->ds_phys->ds_snapnames_zapobj, &numsnaps);
2270         dmu_objset_rele(os, FTAG);
2271         if (error != 0)
2272                 return (error);
2273 
2274         ddpa.ddpa_clonename = name;
2275         ddpa.err_ds = conflsnap;
2276 
2277         return (dsl_sync_task(name, dsl_dataset_promote_check,
2278             dsl_dataset_promote_sync, &ddpa, 2 + numsnaps));
2279 }
2280 
2281 int
2282 dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
2283     dsl_dataset_t *origin_head, boolean_t force)
2284 {
2285         int64_t unused_refres_delta;
2286 
2287         /* they should both be heads */
2288         if (dsl_dataset_is_snapshot(clone) ||
2289             dsl_dataset_is_snapshot(origin_head))
2290                 return (SET_ERROR(EINVAL));
2291 
2292         /* the branch point should be just before them */
2293         if (clone->ds_prev != origin_head->ds_prev)
2294                 return (SET_ERROR(EINVAL));
2295 
2296         /* clone should be the clone (unless they are unrelated) */
2297         if (clone->ds_prev != NULL &&
2298             clone->ds_prev != clone->ds_dir->dd_pool->dp_origin_snap &&
2299             origin_head->ds_object !=
2300             clone->ds_prev->ds_phys->ds_next_snap_obj)
2301                 return (SET_ERROR(EINVAL));
2302 
2303         /* the clone should be a child of the origin */
2304         if (clone->ds_dir->dd_parent != origin_head->ds_dir)
2305                 return (SET_ERROR(EINVAL));
2306 
2307         /* origin_head shouldn't be modified unless 'force' */
2308         if (!force && dsl_dataset_modified_since_lastsnap(origin_head))
2309                 return (SET_ERROR(ETXTBSY));
2310 
2311         /* origin_head should have no long holds (e.g. is not mounted) */
2312         if (dsl_dataset_long_held(origin_head))
2313                 return (SET_ERROR(EBUSY));
2314 
2315         /* check amount of any unconsumed refreservation */
2316         unused_refres_delta =
2317             (int64_t)MIN(origin_head->ds_reserved,
2318             origin_head->ds_phys->ds_unique_bytes) -
2319             (int64_t)MIN(origin_head->ds_reserved,
2320             clone->ds_phys->ds_unique_bytes);
2321 
2322         if (unused_refres_delta > 0 &&
2323             unused_refres_delta >
2324             dsl_dir_space_available(origin_head->ds_dir, NULL, 0, TRUE))
2325                 return (SET_ERROR(ENOSPC));
2326 
2327         /* clone can't be over the head's refquota */
2328         if (origin_head->ds_quota != 0 &&
2329             clone->ds_phys->ds_referenced_bytes > origin_head->ds_quota)
2330                 return (SET_ERROR(EDQUOT));
2331 
2332         return (0);
2333 }
2334 
2335 void
2336 dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
2337     dsl_dataset_t *origin_head, dmu_tx_t *tx)
2338 {
2339         dsl_pool_t *dp = dmu_tx_pool(tx);
2340         int64_t unused_refres_delta;
2341 
2342         ASSERT(clone->ds_reserved == 0);
2343         ASSERT(origin_head->ds_quota == 0 ||
2344             clone->ds_phys->ds_unique_bytes <= origin_head->ds_quota);
2345 
2346         dmu_buf_will_dirty(clone->ds_dbuf, tx);
2347         dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
2348 
2349         if (clone->ds_objset != NULL) {
2350                 dmu_objset_evict(clone->ds_objset);
2351                 clone->ds_objset = NULL;
2352         }
2353 
2354         if (origin_head->ds_objset != NULL) {
2355                 dmu_objset_evict(origin_head->ds_objset);
2356                 origin_head->ds_objset = NULL;
2357         }
2358 
2359         unused_refres_delta =
2360             (int64_t)MIN(origin_head->ds_reserved,
2361             origin_head->ds_phys->ds_unique_bytes) -
2362             (int64_t)MIN(origin_head->ds_reserved,
2363             clone->ds_phys->ds_unique_bytes);
2364 
2365         /*
2366          * Reset origin's unique bytes, if it exists.
2367          */
2368         if (clone->ds_prev) {
2369                 dsl_dataset_t *origin = clone->ds_prev;
2370                 uint64_t comp, uncomp;
2371 
2372                 dmu_buf_will_dirty(origin->ds_dbuf, tx);
2373                 dsl_deadlist_space_range(&clone->ds_deadlist,
2374                     origin->ds_phys->ds_prev_snap_txg, UINT64_MAX,
2375                     &origin->ds_phys->ds_unique_bytes, &comp, &uncomp);
2376         }
2377 
2378         /* swap blkptrs */
2379         {
2380                 blkptr_t tmp;
2381                 tmp = origin_head->ds_phys->ds_bp;
2382                 origin_head->ds_phys->ds_bp = clone->ds_phys->ds_bp;
2383                 clone->ds_phys->ds_bp = tmp;
2384         }
2385 
2386         /* set dd_*_bytes */
2387         {
2388                 int64_t dused, dcomp, duncomp;
2389                 uint64_t cdl_used, cdl_comp, cdl_uncomp;
2390                 uint64_t odl_used, odl_comp, odl_uncomp;
2391 
2392                 ASSERT3U(clone->ds_dir->dd_phys->
2393                     dd_used_breakdown[DD_USED_SNAP], ==, 0);
2394 
2395                 dsl_deadlist_space(&clone->ds_deadlist,
2396                     &cdl_used, &cdl_comp, &cdl_uncomp);
2397                 dsl_deadlist_space(&origin_head->ds_deadlist,
2398                     &odl_used, &odl_comp, &odl_uncomp);
2399 
2400                 dused = clone->ds_phys->ds_referenced_bytes + cdl_used -
2401                     (origin_head->ds_phys->ds_referenced_bytes + odl_used);
2402                 dcomp = clone->ds_phys->ds_compressed_bytes + cdl_comp -
2403                     (origin_head->ds_phys->ds_compressed_bytes + odl_comp);
2404                 duncomp = clone->ds_phys->ds_uncompressed_bytes +
2405                     cdl_uncomp -
2406                     (origin_head->ds_phys->ds_uncompressed_bytes + odl_uncomp);
2407 
2408                 dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_HEAD,
2409                     dused, dcomp, duncomp, tx);
2410                 dsl_dir_diduse_space(clone->ds_dir, DD_USED_HEAD,
2411                     -dused, -dcomp, -duncomp, tx);
2412 
2413                 /*
2414                  * The difference in the space used by snapshots is the
2415                  * difference in snapshot space due to the head's
2416                  * deadlist (since that's the only thing that's
2417                  * changing that affects the snapused).
2418                  */
2419                 dsl_deadlist_space_range(&clone->ds_deadlist,
2420                     origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2421                     &cdl_used, &cdl_comp, &cdl_uncomp);
2422                 dsl_deadlist_space_range(&origin_head->ds_deadlist,
2423                     origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2424                     &odl_used, &odl_comp, &odl_uncomp);
2425                 dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
2426                     DD_USED_HEAD, DD_USED_SNAP, tx);
2427         }
2428 
2429         /* swap ds_*_bytes */
2430         SWITCH64(origin_head->ds_phys->ds_referenced_bytes,
2431             clone->ds_phys->ds_referenced_bytes);
2432         SWITCH64(origin_head->ds_phys->ds_compressed_bytes,
2433             clone->ds_phys->ds_compressed_bytes);
2434         SWITCH64(origin_head->ds_phys->ds_uncompressed_bytes,
2435             clone->ds_phys->ds_uncompressed_bytes);
2436         SWITCH64(origin_head->ds_phys->ds_unique_bytes,
2437             clone->ds_phys->ds_unique_bytes);
2438 
2439         /* apply any parent delta for change in unconsumed refreservation */
2440         dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_REFRSRV,
2441             unused_refres_delta, 0, 0, tx);
2442 
2443         /*
2444          * Swap deadlists.
2445          */
2446         dsl_deadlist_close(&clone->ds_deadlist);
2447         dsl_deadlist_close(&origin_head->ds_deadlist);
2448         SWITCH64(origin_head->ds_phys->ds_deadlist_obj,
2449             clone->ds_phys->ds_deadlist_obj);
2450         dsl_deadlist_open(&clone->ds_deadlist, dp->dp_meta_objset,
2451             clone->ds_phys->ds_deadlist_obj);
2452         dsl_deadlist_open(&origin_head->ds_deadlist, dp->dp_meta_objset,
2453             origin_head->ds_phys->ds_deadlist_obj);
2454 
2455         dsl_scan_ds_clone_swapped(origin_head, clone, tx);
2456 
2457         spa_history_log_internal_ds(clone, "clone swap", tx,
2458             "parent=%s", origin_head->ds_dir->dd_myname);
2459 }
2460 
2461 /*
2462  * Given a pool name and a dataset object number in that pool,
2463  * return the name of that dataset.
2464  */
2465 int
2466 dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf)
2467 {
2468         dsl_pool_t *dp;
2469         dsl_dataset_t *ds;
2470         int error;
2471 
2472         error = dsl_pool_hold(pname, FTAG, &dp);
2473         if (error != 0)
2474                 return (error);
2475 
2476         error = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
2477         if (error == 0) {
2478                 dsl_dataset_name(ds, buf);
2479                 dsl_dataset_rele(ds, FTAG);
2480         }
2481         dsl_pool_rele(dp, FTAG);
2482 
2483         return (error);
2484 }
2485 
2486 int
2487 dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota,
2488     uint64_t asize, uint64_t inflight, uint64_t *used, uint64_t *ref_rsrv)
2489 {
2490         int error = 0;
2491 
2492         ASSERT3S(asize, >, 0);
2493 
2494         /*
2495          * *ref_rsrv is the portion of asize that will come from any
2496          * unconsumed refreservation space.
2497          */
2498         *ref_rsrv = 0;
2499 
2500         mutex_enter(&ds->ds_lock);
2501         /*
2502          * Make a space adjustment for reserved bytes.
2503          */
2504         if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes) {
2505                 ASSERT3U(*used, >=,
2506                     ds->ds_reserved - ds->ds_phys->ds_unique_bytes);
2507                 *used -= (ds->ds_reserved - ds->ds_phys->ds_unique_bytes);
2508                 *ref_rsrv =
2509                     asize - MIN(asize, parent_delta(ds, asize + inflight));
2510         }
2511 
2512         if (!check_quota || ds->ds_quota == 0) {
2513                 mutex_exit(&ds->ds_lock);
2514                 return (0);
2515         }
2516         /*
2517          * If they are requesting more space, and our current estimate
2518          * is over quota, they get to try again unless the actual
2519          * on-disk is over quota and there are no pending changes (which
2520          * may free up space for us).
2521          */
2522         if (ds->ds_phys->ds_referenced_bytes + inflight >= ds->ds_quota) {
2523                 if (inflight > 0 ||
2524                     ds->ds_phys->ds_referenced_bytes < ds->ds_quota)
2525                         error = SET_ERROR(ERESTART);
2526                 else
2527                         error = SET_ERROR(EDQUOT);
2528         }
2529         mutex_exit(&ds->ds_lock);
2530 
2531         return (error);
2532 }
2533 
2534 typedef struct dsl_dataset_set_qr_arg {
2535         const char *ddsqra_name;
2536         zprop_source_t ddsqra_source;
2537         uint64_t ddsqra_value;
2538 } dsl_dataset_set_qr_arg_t;
2539 
2540 
2541 /* ARGSUSED */
2542 static int
2543 dsl_dataset_set_refquota_check(void *arg, dmu_tx_t *tx)
2544 {
2545         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2546         dsl_pool_t *dp = dmu_tx_pool(tx);
2547         dsl_dataset_t *ds;
2548         int error;
2549         uint64_t newval;
2550 
2551         if (spa_version(dp->dp_spa) < SPA_VERSION_REFQUOTA)
2552                 return (SET_ERROR(ENOTSUP));
2553 
2554         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
2555         if (error != 0)
2556                 return (error);
2557 
2558         if (dsl_dataset_is_snapshot(ds)) {
2559                 dsl_dataset_rele(ds, FTAG);
2560                 return (SET_ERROR(EINVAL));
2561         }
2562 
2563         error = dsl_prop_predict(ds->ds_dir,
2564             zfs_prop_to_name(ZFS_PROP_REFQUOTA),
2565             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
2566         if (error != 0) {
2567                 dsl_dataset_rele(ds, FTAG);
2568                 return (error);
2569         }
2570 
2571         if (newval == 0) {
2572                 dsl_dataset_rele(ds, FTAG);
2573                 return (0);
2574         }
2575 
2576         if (newval < ds->ds_phys->ds_referenced_bytes ||
2577             newval < ds->ds_reserved) {
2578                 dsl_dataset_rele(ds, FTAG);
2579                 return (SET_ERROR(ENOSPC));
2580         }
2581 
2582         dsl_dataset_rele(ds, FTAG);
2583         return (0);
2584 }
2585 
2586 static void
2587 dsl_dataset_set_refquota_sync(void *arg, dmu_tx_t *tx)
2588 {
2589         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2590         dsl_pool_t *dp = dmu_tx_pool(tx);
2591         dsl_dataset_t *ds;
2592         uint64_t newval;
2593 
2594         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
2595 
2596         dsl_prop_set_sync_impl(ds,
2597             zfs_prop_to_name(ZFS_PROP_REFQUOTA),
2598             ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
2599             &ddsqra->ddsqra_value, tx);
2600 
2601         VERIFY0(dsl_prop_get_int_ds(ds,
2602             zfs_prop_to_name(ZFS_PROP_REFQUOTA), &newval));
2603 
2604         if (ds->ds_quota != newval) {
2605                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
2606                 ds->ds_quota = newval;
2607         }
2608         dsl_dataset_rele(ds, FTAG);
2609 }
2610 
2611 int
2612 dsl_dataset_set_refquota(const char *dsname, zprop_source_t source,
2613     uint64_t refquota)
2614 {
2615         dsl_dataset_set_qr_arg_t ddsqra;
2616 
2617         ddsqra.ddsqra_name = dsname;
2618         ddsqra.ddsqra_source = source;
2619         ddsqra.ddsqra_value = refquota;
2620 
2621         return (dsl_sync_task(dsname, dsl_dataset_set_refquota_check,
2622             dsl_dataset_set_refquota_sync, &ddsqra, 0));
2623 }
2624 
2625 static int
2626 dsl_dataset_set_refreservation_check(void *arg, dmu_tx_t *tx)
2627 {
2628         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2629         dsl_pool_t *dp = dmu_tx_pool(tx);
2630         dsl_dataset_t *ds;
2631         int error;
2632         uint64_t newval, unique;
2633 
2634         if (spa_version(dp->dp_spa) < SPA_VERSION_REFRESERVATION)
2635                 return (SET_ERROR(ENOTSUP));
2636 
2637         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
2638         if (error != 0)
2639                 return (error);
2640 
2641         if (dsl_dataset_is_snapshot(ds)) {
2642                 dsl_dataset_rele(ds, FTAG);
2643                 return (SET_ERROR(EINVAL));
2644         }
2645 
2646         error = dsl_prop_predict(ds->ds_dir,
2647             zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
2648             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
2649         if (error != 0) {
2650                 dsl_dataset_rele(ds, FTAG);
2651                 return (error);
2652         }
2653 
2654         /*
2655          * If we are doing the preliminary check in open context, the
2656          * space estimates may be inaccurate.
2657          */
2658         if (!dmu_tx_is_syncing(tx)) {
2659                 dsl_dataset_rele(ds, FTAG);
2660                 return (0);
2661         }
2662 
2663         mutex_enter(&ds->ds_lock);
2664         if (!DS_UNIQUE_IS_ACCURATE(ds))
2665                 dsl_dataset_recalc_head_uniq(ds);
2666         unique = ds->ds_phys->ds_unique_bytes;
2667         mutex_exit(&ds->ds_lock);
2668 
2669         if (MAX(unique, newval) > MAX(unique, ds->ds_reserved)) {
2670                 uint64_t delta = MAX(unique, newval) -
2671                     MAX(unique, ds->ds_reserved);
2672 
2673                 if (delta >
2674                     dsl_dir_space_available(ds->ds_dir, NULL, 0, B_TRUE) ||
2675                     (ds->ds_quota > 0 && newval > ds->ds_quota)) {
2676                         dsl_dataset_rele(ds, FTAG);
2677                         return (SET_ERROR(ENOSPC));
2678                 }
2679         }
2680 
2681         dsl_dataset_rele(ds, FTAG);
2682         return (0);
2683 }
2684 
2685 void
2686 dsl_dataset_set_refreservation_sync_impl(dsl_dataset_t *ds,
2687     zprop_source_t source, uint64_t value, dmu_tx_t *tx)
2688 {
2689         uint64_t newval;
2690         uint64_t unique;
2691         int64_t delta;
2692 
2693         dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
2694             source, sizeof (value), 1, &value, tx);
2695 
2696         VERIFY0(dsl_prop_get_int_ds(ds,
2697             zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &newval));
2698 
2699         dmu_buf_will_dirty(ds->ds_dbuf, tx);
2700         mutex_enter(&ds->ds_dir->dd_lock);
2701         mutex_enter(&ds->ds_lock);
2702         ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
2703         unique = ds->ds_phys->ds_unique_bytes;
2704         delta = MAX(0, (int64_t)(newval - unique)) -
2705             MAX(0, (int64_t)(ds->ds_reserved - unique));
2706         ds->ds_reserved = newval;
2707         mutex_exit(&ds->ds_lock);
2708 
2709         dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx);
2710         mutex_exit(&ds->ds_dir->dd_lock);
2711 }
2712 
2713 static void
2714 dsl_dataset_set_refreservation_sync(void *arg, dmu_tx_t *tx)
2715 {
2716         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2717         dsl_pool_t *dp = dmu_tx_pool(tx);
2718         dsl_dataset_t *ds;
2719 
2720         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
2721         dsl_dataset_set_refreservation_sync_impl(ds,
2722             ddsqra->ddsqra_source, ddsqra->ddsqra_value, tx);
2723         dsl_dataset_rele(ds, FTAG);
2724 }
2725 
2726 int
2727 dsl_dataset_set_refreservation(const char *dsname, zprop_source_t source,
2728     uint64_t refreservation)
2729 {
2730         dsl_dataset_set_qr_arg_t ddsqra;
2731 
2732         ddsqra.ddsqra_name = dsname;
2733         ddsqra.ddsqra_source = source;
2734         ddsqra.ddsqra_value = refreservation;
2735 
2736         return (dsl_sync_task(dsname, dsl_dataset_set_refreservation_check,
2737             dsl_dataset_set_refreservation_sync, &ddsqra, 0));
2738 }
2739 
2740 /*
2741  * Return (in *usedp) the amount of space written in new that is not
2742  * present in oldsnap.  New may be a snapshot or the head.  Old must be
2743  * a snapshot before new, in new's filesystem (or its origin).  If not then
2744  * fail and return EINVAL.
2745  *
2746  * The written space is calculated by considering two components:  First, we
2747  * ignore any freed space, and calculate the written as new's used space
2748  * minus old's used space.  Next, we add in the amount of space that was freed
2749  * between the two snapshots, thus reducing new's used space relative to old's.
2750  * Specifically, this is the space that was born before old->ds_creation_txg,
2751  * and freed before new (ie. on new's deadlist or a previous deadlist).
2752  *
2753  * space freed                         [---------------------]
2754  * snapshots                       ---O-------O--------O-------O------
2755  *                                         oldsnap            new
2756  */
2757 int
2758 dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
2759     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
2760 {
2761         int err = 0;
2762         uint64_t snapobj;
2763         dsl_pool_t *dp = new->ds_dir->dd_pool;
2764 
2765         ASSERT(dsl_pool_config_held(dp));
2766 
2767         *usedp = 0;
2768         *usedp += new->ds_phys->ds_referenced_bytes;
2769         *usedp -= oldsnap->ds_phys->ds_referenced_bytes;
2770 
2771         *compp = 0;
2772         *compp += new->ds_phys->ds_compressed_bytes;
2773         *compp -= oldsnap->ds_phys->ds_compressed_bytes;
2774 
2775         *uncompp = 0;
2776         *uncompp += new->ds_phys->ds_uncompressed_bytes;
2777         *uncompp -= oldsnap->ds_phys->ds_uncompressed_bytes;
2778 
2779         snapobj = new->ds_object;
2780         while (snapobj != oldsnap->ds_object) {
2781                 dsl_dataset_t *snap;
2782                 uint64_t used, comp, uncomp;
2783 
2784                 if (snapobj == new->ds_object) {
2785                         snap = new;
2786                 } else {
2787                         err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
2788                         if (err != 0)
2789                                 break;
2790                 }
2791 
2792                 if (snap->ds_phys->ds_prev_snap_txg ==
2793                     oldsnap->ds_phys->ds_creation_txg) {
2794                         /*
2795                          * The blocks in the deadlist can not be born after
2796                          * ds_prev_snap_txg, so get the whole deadlist space,
2797                          * which is more efficient (especially for old-format
2798                          * deadlists).  Unfortunately the deadlist code
2799                          * doesn't have enough information to make this
2800                          * optimization itself.
2801                          */
2802                         dsl_deadlist_space(&snap->ds_deadlist,
2803                             &used, &comp, &uncomp);
2804                 } else {
2805                         dsl_deadlist_space_range(&snap->ds_deadlist,
2806                             0, oldsnap->ds_phys->ds_creation_txg,
2807                             &used, &comp, &uncomp);
2808                 }
2809                 *usedp += used;
2810                 *compp += comp;
2811                 *uncompp += uncomp;
2812 
2813                 /*
2814                  * If we get to the beginning of the chain of snapshots
2815                  * (ds_prev_snap_obj == 0) before oldsnap, then oldsnap
2816                  * was not a snapshot of/before new.
2817                  */
2818                 snapobj = snap->ds_phys->ds_prev_snap_obj;
2819                 if (snap != new)
2820                         dsl_dataset_rele(snap, FTAG);
2821                 if (snapobj == 0) {
2822                         err = SET_ERROR(EINVAL);
2823                         break;
2824                 }
2825 
2826         }
2827         return (err);
2828 }
2829 
2830 /*
2831  * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
2832  * lastsnap, and all snapshots in between are deleted.
2833  *
2834  * blocks that would be freed            [---------------------------]
2835  * snapshots                       ---O-------O--------O-------O--------O
2836  *                                        firstsnap        lastsnap
2837  *
2838  * This is the set of blocks that were born after the snap before firstsnap,
2839  * (birth > firstsnap->prev_snap_txg) and died before the snap after the
2840  * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
2841  * We calculate this by iterating over the relevant deadlists (from the snap
2842  * after lastsnap, backward to the snap after firstsnap), summing up the
2843  * space on the deadlist that was born after the snap before firstsnap.
2844  */
2845 int
2846 dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
2847     dsl_dataset_t *lastsnap,
2848     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
2849 {
2850         int err = 0;
2851         uint64_t snapobj;
2852         dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
2853 
2854         ASSERT(dsl_dataset_is_snapshot(firstsnap));
2855         ASSERT(dsl_dataset_is_snapshot(lastsnap));
2856 
2857         /*
2858          * Check that the snapshots are in the same dsl_dir, and firstsnap
2859          * is before lastsnap.
2860          */
2861         if (firstsnap->ds_dir != lastsnap->ds_dir ||
2862             firstsnap->ds_phys->ds_creation_txg >
2863             lastsnap->ds_phys->ds_creation_txg)
2864                 return (SET_ERROR(EINVAL));
2865 
2866         *usedp = *compp = *uncompp = 0;
2867 
2868         snapobj = lastsnap->ds_phys->ds_next_snap_obj;
2869         while (snapobj != firstsnap->ds_object) {
2870                 dsl_dataset_t *ds;
2871                 uint64_t used, comp, uncomp;
2872 
2873                 err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
2874                 if (err != 0)
2875                         break;
2876 
2877                 dsl_deadlist_space_range(&ds->ds_deadlist,
2878                     firstsnap->ds_phys->ds_prev_snap_txg, UINT64_MAX,
2879                     &used, &comp, &uncomp);
2880                 *usedp += used;
2881                 *compp += comp;
2882                 *uncompp += uncomp;
2883 
2884                 snapobj = ds->ds_phys->ds_prev_snap_obj;
2885                 ASSERT3U(snapobj, !=, 0);
2886                 dsl_dataset_rele(ds, FTAG);
2887         }
2888         return (err);
2889 }
2890 
2891 /*
2892  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
2893  * For example, they could both be snapshots of the same filesystem, and
2894  * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
2895  * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
2896  * filesystem.  Or 'earlier' could be the origin's origin.
2897  */
2898 boolean_t
2899 dsl_dataset_is_before(dsl_dataset_t *later, dsl_dataset_t *earlier)
2900 {
2901         dsl_pool_t *dp = later->ds_dir->dd_pool;
2902         int error;
2903         boolean_t ret;
2904 
2905         ASSERT(dsl_pool_config_held(dp));
2906 
2907         if (earlier->ds_phys->ds_creation_txg >=
2908             later->ds_phys->ds_creation_txg)
2909                 return (B_FALSE);
2910 
2911         if (later->ds_dir == earlier->ds_dir)
2912                 return (B_TRUE);
2913         if (!dsl_dir_is_clone(later->ds_dir))
2914                 return (B_FALSE);
2915 
2916         if (later->ds_dir->dd_phys->dd_origin_obj == earlier->ds_object)
2917                 return (B_TRUE);
2918         dsl_dataset_t *origin;
2919         error = dsl_dataset_hold_obj(dp,
2920             later->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin);
2921         if (error != 0)
2922                 return (B_FALSE);
2923         ret = dsl_dataset_is_before(origin, earlier);
2924         dsl_dataset_rele(origin, FTAG);
2925         return (ret);
2926 }