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 
 104         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 105         mutex_enter(&ds->ds_lock);
 106         delta = parent_delta(ds, used);
 107         ds->ds_phys->ds_referenced_bytes += used;
 108         ds->ds_phys->ds_compressed_bytes += compressed;
 109         ds->ds_phys->ds_uncompressed_bytes += uncompressed;
 110         ds->ds_phys->ds_unique_bytes += used;
 111         mutex_exit(&ds->ds_lock);
 112         dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
 113             compressed, uncompressed, tx);
 114         dsl_dir_transfer_space(ds->ds_dir, used - delta,
 115             DD_USED_REFRSRV, DD_USED_HEAD, tx);
 116 }
 117 
 118 int
 119 dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
 120     boolean_t async)
 121 {
 122         if (BP_IS_HOLE(bp))
 123                 return (0);
 124 
 125         ASSERT(dmu_tx_is_syncing(tx));
 126         ASSERT(bp->blk_birth <= tx->tx_txg);
 127 
 128         int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
 129         int compressed = BP_GET_PSIZE(bp);
 130         int uncompressed = BP_GET_UCSIZE(bp);
 131 
 132         ASSERT(used > 0);
 133         if (ds == NULL) {
 134                 dsl_free(tx->tx_pool, tx->tx_txg, bp);
 135                 dsl_pool_mos_diduse_space(tx->tx_pool,
 136                     -used, -compressed, -uncompressed);
 137                 return (used);
 138         }
 139         ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool);
 140 
 141         ASSERT(!dsl_dataset_is_snapshot(ds));
 142         dmu_buf_will_dirty(ds->ds_dbuf, tx);
 143 
 144         if (bp->blk_birth > ds->ds_phys->ds_prev_snap_txg) {
 145                 int64_t delta;
 146 
 147                 dprintf_bp(bp, "freeing ds=%llu", ds->ds_object);
 148                 dsl_free(tx->tx_pool, tx->tx_txg, bp);
 149 
 150                 mutex_enter(&ds->ds_lock);
 151                 ASSERT(ds->ds_phys->ds_unique_bytes >= used ||
 152                     !DS_UNIQUE_IS_ACCURATE(ds));
 153                 delta = parent_delta(ds, -used);
 154                 ds->ds_phys->ds_unique_bytes -= used;
 155                 mutex_exit(&ds->ds_lock);
 156                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
 157                     delta, -compressed, -uncompressed, tx);
 158                 dsl_dir_transfer_space(ds->ds_dir, -used - delta,
 159                     DD_USED_REFRSRV, DD_USED_HEAD, tx);
 160         } else {
 161                 dprintf_bp(bp, "putting on dead list: %s", "");
 162                 if (async) {
 163                         /*
 164                          * We are here as part of zio's write done callback,
 165                          * which means we're a zio interrupt thread.  We can't
 166                          * call dsl_deadlist_insert() now because it may block
 167                          * waiting for I/O.  Instead, put bp on the deferred
 168                          * queue and let dsl_pool_sync() finish the job.
 169                          */
 170                         bplist_append(&ds->ds_pending_deadlist, bp);
 171                 } else {
 172                         dsl_deadlist_insert(&ds->ds_deadlist, bp, tx);
 173                 }
 174                 ASSERT3U(ds->ds_prev->ds_object, ==,
 175                     ds->ds_phys->ds_prev_snap_obj);
 176                 ASSERT(ds->ds_prev->ds_phys->ds_num_children > 0);
 177                 /* if (bp->blk_birth > prev prev snap txg) prev unique += bs */
 178                 if (ds->ds_prev->ds_phys->ds_next_snap_obj ==
 179                     ds->ds_object && bp->blk_birth >
 180                     ds->ds_prev->ds_phys->ds_prev_snap_txg) {
 181                         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
 182                         mutex_enter(&ds->ds_prev->ds_lock);
 183                         ds->ds_prev->ds_phys->ds_unique_bytes += used;
 184                         mutex_exit(&ds->ds_prev->ds_lock);
 185                 }
 186                 if (bp->blk_birth > ds->ds_dir->dd_origin_txg) {
 187                         dsl_dir_transfer_space(ds->ds_dir, used,
 188                             DD_USED_HEAD, DD_USED_SNAP, tx);
 189                 }
 190         }
 191         mutex_enter(&ds->ds_lock);
 192         ASSERT3U(ds->ds_phys->ds_referenced_bytes, >=, used);
 193         ds->ds_phys->ds_referenced_bytes -= used;
 194         ASSERT3U(ds->ds_phys->ds_compressed_bytes, >=, compressed);
 195         ds->ds_phys->ds_compressed_bytes -= compressed;
 196         ASSERT3U(ds->ds_phys->ds_uncompressed_bytes, >=, uncompressed);
 197         ds->ds_phys->ds_uncompressed_bytes -= uncompressed;
 198         mutex_exit(&ds->ds_lock);
 199 
 200         return (used);
 201 }
 202 
 203 uint64_t
 204 dsl_dataset_prev_snap_txg(dsl_dataset_t *ds)
 205 {
 206         uint64_t trysnap = 0;
 207 
 208         if (ds == NULL)
 209                 return (0);
 210         /*
 211          * The snapshot creation could fail, but that would cause an
 212          * incorrect FALSE return, which would only result in an
 213          * overestimation of the amount of space that an operation would
 214          * consume, which is OK.
 215          *
 216          * There's also a small window where we could miss a pending
 217          * snapshot, because we could set the sync task in the quiescing
 218          * phase.  So this should only be used as a guess.
 219          */
 220         if (ds->ds_trysnap_txg >
 221             spa_last_synced_txg(ds->ds_dir->dd_pool->dp_spa))
 222                 trysnap = ds->ds_trysnap_txg;
 223         return (MAX(ds->ds_phys->ds_prev_snap_txg, trysnap));
 224 }
 225 
 226 boolean_t
 227 dsl_dataset_block_freeable(dsl_dataset_t *ds, const blkptr_t *bp,
 228     uint64_t blk_birth)
 229 {
 230         if (blk_birth <= dsl_dataset_prev_snap_txg(ds))
 231                 return (B_FALSE);
 232 
 233         ddt_prefetch(dsl_dataset_get_spa(ds), bp);
 234 
 235         return (B_TRUE);
 236 }
 237 
 238 /* ARGSUSED */
 239 static void
 240 dsl_dataset_evict(dmu_buf_t *db, void *dsv)
 241 {
 242         dsl_dataset_t *ds = dsv;
 243 
 244         ASSERT(ds->ds_owner == NULL);
 245 
 246         unique_remove(ds->ds_fsid_guid);
 247 
 248         if (ds->ds_objset != NULL)
 249                 dmu_objset_evict(ds->ds_objset);
 250 
 251         if (ds->ds_prev) {
 252                 dsl_dataset_rele(ds->ds_prev, ds);
 253                 ds->ds_prev = NULL;
 254         }
 255 
 256         bplist_destroy(&ds->ds_pending_deadlist);
 257         if (ds->ds_phys->ds_deadlist_obj != 0)
 258                 dsl_deadlist_close(&ds->ds_deadlist);
 259         if (ds->ds_dir)
 260                 dsl_dir_rele(ds->ds_dir, ds);
 261 
 262         ASSERT(!list_link_active(&ds->ds_synced_link));
 263 
 264         mutex_destroy(&ds->ds_lock);
 265         mutex_destroy(&ds->ds_opening_lock);
 266         refcount_destroy(&ds->ds_longholds);
 267 
 268         kmem_free(ds, sizeof (dsl_dataset_t));
 269 }
 270 
 271 int
 272 dsl_dataset_get_snapname(dsl_dataset_t *ds)
 273 {
 274         dsl_dataset_phys_t *headphys;
 275         int err;
 276         dmu_buf_t *headdbuf;
 277         dsl_pool_t *dp = ds->ds_dir->dd_pool;
 278         objset_t *mos = dp->dp_meta_objset;
 279 
 280         if (ds->ds_snapname[0])
 281                 return (0);
 282         if (ds->ds_phys->ds_next_snap_obj == 0)
 283                 return (0);
 284 
 285         err = dmu_bonus_hold(mos, ds->ds_dir->dd_phys->dd_head_dataset_obj,
 286             FTAG, &headdbuf);
 287         if (err != 0)
 288                 return (err);
 289         headphys = headdbuf->db_data;
 290         err = zap_value_search(dp->dp_meta_objset,
 291             headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
 292         dmu_buf_rele(headdbuf, FTAG);
 293         return (err);
 294 }
 295 
 296 int
 297 dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value)
 298 {
 299         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 300         uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
 301         matchtype_t mt;
 302         int err;
 303 
 304         if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
 305                 mt = MT_FIRST;
 306         else
 307                 mt = MT_EXACT;
 308 
 309         err = zap_lookup_norm(mos, snapobj, name, 8, 1,
 310             value, mt, NULL, 0, NULL);
 311         if (err == ENOTSUP && mt == MT_FIRST)
 312                 err = zap_lookup(mos, snapobj, name, 8, 1, value);
 313         return (err);
 314 }
 315 
 316 int
 317 dsl_dataset_snap_remove(dsl_dataset_t *ds, const char *name, dmu_tx_t *tx)
 318 {
 319         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 320         uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
 321         matchtype_t mt;
 322         int err;
 323 
 324         dsl_dir_snap_cmtime_update(ds->ds_dir);
 325 
 326         if (ds->ds_phys->ds_flags & DS_FLAG_CI_DATASET)
 327                 mt = MT_FIRST;
 328         else
 329                 mt = MT_EXACT;
 330 
 331         err = zap_remove_norm(mos, snapobj, name, mt, tx);
 332         if (err == ENOTSUP && mt == MT_FIRST)
 333                 err = zap_remove(mos, snapobj, name, tx);
 334         return (err);
 335 }
 336 
 337 int
 338 dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
 339     dsl_dataset_t **dsp)
 340 {
 341         objset_t *mos = dp->dp_meta_objset;
 342         dmu_buf_t *dbuf;
 343         dsl_dataset_t *ds;
 344         int err;
 345         dmu_object_info_t doi;
 346 
 347         ASSERT(dsl_pool_config_held(dp));
 348 
 349         err = dmu_bonus_hold(mos, dsobj, tag, &dbuf);
 350         if (err != 0)
 351                 return (err);
 352 
 353         /* Make sure dsobj has the correct object type. */
 354         dmu_object_info_from_db(dbuf, &doi);
 355         if (doi.doi_bonus_type != DMU_OT_DSL_DATASET) {
 356                 dmu_buf_rele(dbuf, tag);
 357                 return (SET_ERROR(EINVAL));
 358         }
 359 
 360         ds = dmu_buf_get_user(dbuf);
 361         if (ds == NULL) {
 362                 dsl_dataset_t *winner = NULL;
 363 
 364                 ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP);
 365                 ds->ds_dbuf = dbuf;
 366                 ds->ds_object = dsobj;
 367                 ds->ds_phys = dbuf->db_data;
 368 
 369                 mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
 370                 mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
 371                 mutex_init(&ds->ds_sendstream_lock, NULL, MUTEX_DEFAULT, NULL);
 372                 refcount_create(&ds->ds_longholds);
 373 
 374                 bplist_create(&ds->ds_pending_deadlist);
 375                 dsl_deadlist_open(&ds->ds_deadlist,
 376                     mos, ds->ds_phys->ds_deadlist_obj);
 377 
 378                 list_create(&ds->ds_sendstreams, sizeof (dmu_sendarg_t),
 379                     offsetof(dmu_sendarg_t, dsa_link));
 380 
 381                 if (err == 0) {
 382                         err = dsl_dir_hold_obj(dp,
 383                             ds->ds_phys->ds_dir_obj, NULL, ds, &ds->ds_dir);
 384                 }
 385                 if (err != 0) {
 386                         mutex_destroy(&ds->ds_lock);
 387                         mutex_destroy(&ds->ds_opening_lock);
 388                         refcount_destroy(&ds->ds_longholds);
 389                         bplist_destroy(&ds->ds_pending_deadlist);
 390                         dsl_deadlist_close(&ds->ds_deadlist);
 391                         kmem_free(ds, sizeof (dsl_dataset_t));
 392                         dmu_buf_rele(dbuf, tag);
 393                         return (err);
 394                 }
 395 
 396                 if (!dsl_dataset_is_snapshot(ds)) {
 397                         ds->ds_snapname[0] = '\0';
 398                         if (ds->ds_phys->ds_prev_snap_obj != 0) {
 399                                 err = dsl_dataset_hold_obj(dp,
 400                                     ds->ds_phys->ds_prev_snap_obj,
 401                                     ds, &ds->ds_prev);
 402                         }
 403                 } else {
 404                         if (zfs_flags & ZFS_DEBUG_SNAPNAMES)
 405                                 err = dsl_dataset_get_snapname(ds);
 406                         if (err == 0 && ds->ds_phys->ds_userrefs_obj != 0) {
 407                                 err = zap_count(
 408                                     ds->ds_dir->dd_pool->dp_meta_objset,
 409                                     ds->ds_phys->ds_userrefs_obj,
 410                                     &ds->ds_userrefs);
 411                         }
 412                 }
 413 
 414                 if (err == 0 && !dsl_dataset_is_snapshot(ds)) {
 415                         err = dsl_prop_get_int_ds(ds,
 416                             zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
 417                             &ds->ds_reserved);
 418                         if (err == 0) {
 419                                 err = dsl_prop_get_int_ds(ds,
 420                                     zfs_prop_to_name(ZFS_PROP_REFQUOTA),
 421                                     &ds->ds_quota);
 422                         }
 423                 } else {
 424                         ds->ds_reserved = ds->ds_quota = 0;
 425                 }
 426 
 427                 if (err != 0 || (winner = dmu_buf_set_user_ie(dbuf, ds,
 428                     &ds->ds_phys, dsl_dataset_evict)) != NULL) {
 429                         bplist_destroy(&ds->ds_pending_deadlist);
 430                         dsl_deadlist_close(&ds->ds_deadlist);
 431                         if (ds->ds_prev)
 432                                 dsl_dataset_rele(ds->ds_prev, ds);
 433                         dsl_dir_rele(ds->ds_dir, ds);
 434                         mutex_destroy(&ds->ds_lock);
 435                         mutex_destroy(&ds->ds_opening_lock);
 436                         refcount_destroy(&ds->ds_longholds);
 437                         kmem_free(ds, sizeof (dsl_dataset_t));
 438                         if (err != 0) {
 439                                 dmu_buf_rele(dbuf, tag);
 440                                 return (err);
 441                         }
 442                         ds = winner;
 443                 } else {
 444                         ds->ds_fsid_guid =
 445                             unique_insert(ds->ds_phys->ds_fsid_guid);
 446                 }
 447         }
 448         ASSERT3P(ds->ds_dbuf, ==, dbuf);
 449         ASSERT3P(ds->ds_phys, ==, dbuf->db_data);
 450         ASSERT(ds->ds_phys->ds_prev_snap_obj != 0 ||
 451             spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
 452             dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
 453         *dsp = ds;
 454         return (0);
 455 }
 456 
 457 int
 458 dsl_dataset_hold(dsl_pool_t *dp, const char *name,
 459     void *tag, dsl_dataset_t **dsp)
 460 {
 461         dsl_dir_t *dd;
 462         const char *snapname;
 463         uint64_t obj;
 464         int err = 0;
 465 
 466         err = dsl_dir_hold(dp, name, FTAG, &dd, &snapname);
 467         if (err != 0)
 468                 return (err);
 469 
 470         ASSERT(dsl_pool_config_held(dp));
 471         obj = dd->dd_phys->dd_head_dataset_obj;
 472         if (obj != 0)
 473                 err = dsl_dataset_hold_obj(dp, obj, tag, dsp);
 474         else
 475                 err = SET_ERROR(ENOENT);
 476 
 477         /* we may be looking for a snapshot */
 478         if (err == 0 && snapname != NULL) {
 479                 dsl_dataset_t *ds;
 480 
 481                 if (*snapname++ != '@') {
 482                         dsl_dataset_rele(*dsp, tag);
 483                         dsl_dir_rele(dd, FTAG);
 484                         return (SET_ERROR(ENOENT));
 485                 }
 486 
 487                 dprintf("looking for snapshot '%s'\n", snapname);
 488                 err = dsl_dataset_snap_lookup(*dsp, snapname, &obj);
 489                 if (err == 0)
 490                         err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
 491                 dsl_dataset_rele(*dsp, tag);
 492 
 493                 if (err == 0) {
 494                         mutex_enter(&ds->ds_lock);
 495                         if (ds->ds_snapname[0] == 0)
 496                                 (void) strlcpy(ds->ds_snapname, snapname,
 497                                     sizeof (ds->ds_snapname));
 498                         mutex_exit(&ds->ds_lock);
 499                         *dsp = ds;
 500                 }
 501         }
 502 
 503         dsl_dir_rele(dd, FTAG);
 504         return (err);
 505 }
 506 
 507 int
 508 dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj,
 509     void *tag, dsl_dataset_t **dsp)
 510 {
 511         int err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp);
 512         if (err != 0)
 513                 return (err);
 514         if (!dsl_dataset_tryown(*dsp, tag)) {
 515                 dsl_dataset_rele(*dsp, tag);
 516                 *dsp = NULL;
 517                 return (SET_ERROR(EBUSY));
 518         }
 519         return (0);
 520 }
 521 
 522 int
 523 dsl_dataset_own(dsl_pool_t *dp, const char *name,
 524     void *tag, dsl_dataset_t **dsp)
 525 {
 526         int err = dsl_dataset_hold(dp, name, tag, dsp);
 527         if (err != 0)
 528                 return (err);
 529         if (!dsl_dataset_tryown(*dsp, tag)) {
 530                 dsl_dataset_rele(*dsp, tag);
 531                 return (SET_ERROR(EBUSY));
 532         }
 533         return (0);
 534 }
 535 
 536 /*
 537  * See the comment above dsl_pool_hold() for details.  In summary, a long
 538  * hold is used to prevent destruction of a dataset while the pool hold
 539  * is dropped, allowing other concurrent operations (e.g. spa_sync()).
 540  *
 541  * The dataset and pool must be held when this function is called.  After it
 542  * is called, the pool hold may be released while the dataset is still held
 543  * and accessed.
 544  */
 545 void
 546 dsl_dataset_long_hold(dsl_dataset_t *ds, void *tag)
 547 {
 548         ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
 549         (void) refcount_add(&ds->ds_longholds, tag);
 550 }
 551 
 552 void
 553 dsl_dataset_long_rele(dsl_dataset_t *ds, void *tag)
 554 {
 555         (void) refcount_remove(&ds->ds_longholds, tag);
 556 }
 557 
 558 /* Return B_TRUE if there are any long holds on this dataset. */
 559 boolean_t
 560 dsl_dataset_long_held(dsl_dataset_t *ds)
 561 {
 562         return (!refcount_is_zero(&ds->ds_longholds));
 563 }
 564 
 565 void
 566 dsl_dataset_name(dsl_dataset_t *ds, char *name)
 567 {
 568         if (ds == NULL) {
 569                 (void) strcpy(name, "mos");
 570         } else {
 571                 dsl_dir_name(ds->ds_dir, name);
 572                 VERIFY0(dsl_dataset_get_snapname(ds));
 573                 if (ds->ds_snapname[0]) {
 574                         (void) strcat(name, "@");
 575                         /*
 576                          * We use a "recursive" mutex so that we
 577                          * can call dprintf_ds() with ds_lock held.
 578                          */
 579                         if (!MUTEX_HELD(&ds->ds_lock)) {
 580                                 mutex_enter(&ds->ds_lock);
 581                                 (void) strcat(name, ds->ds_snapname);
 582                                 mutex_exit(&ds->ds_lock);
 583                         } else {
 584                                 (void) strcat(name, ds->ds_snapname);
 585                         }
 586                 }
 587         }
 588 }
 589 
 590 void
 591 dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
 592 {
 593         dmu_buf_rele(ds->ds_dbuf, tag);
 594 }
 595 
 596 void
 597 dsl_dataset_disown(dsl_dataset_t *ds, void *tag)
 598 {
 599         ASSERT(ds->ds_owner == tag && ds->ds_dbuf != NULL);
 600 
 601         mutex_enter(&ds->ds_lock);
 602         ds->ds_owner = NULL;
 603         mutex_exit(&ds->ds_lock);
 604         dsl_dataset_long_rele(ds, tag);
 605         if (ds->ds_dbuf != NULL)
 606                 dsl_dataset_rele(ds, tag);
 607         else
 608                 dsl_dataset_evict(NULL, ds);
 609 }
 610 
 611 boolean_t
 612 dsl_dataset_tryown(dsl_dataset_t *ds, void *tag)
 613 {
 614         boolean_t gotit = FALSE;
 615 
 616         mutex_enter(&ds->ds_lock);
 617         if (ds->ds_owner == NULL && !DS_IS_INCONSISTENT(ds)) {
 618                 ds->ds_owner = tag;
 619                 dsl_dataset_long_hold(ds, tag);
 620                 gotit = TRUE;
 621         }
 622         mutex_exit(&ds->ds_lock);
 623         return (gotit);
 624 }
 625 
 626 uint64_t
 627 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
 628     uint64_t flags, dmu_tx_t *tx)
 629 {
 630         dsl_pool_t *dp = dd->dd_pool;
 631         dmu_buf_t *dbuf;
 632         dsl_dataset_phys_t *dsphys;
 633         uint64_t dsobj;
 634         objset_t *mos = dp->dp_meta_objset;
 635 
 636         if (origin == NULL)
 637                 origin = dp->dp_origin_snap;
 638 
 639         ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
 640         ASSERT(origin == NULL || origin->ds_phys->ds_num_children > 0);
 641         ASSERT(dmu_tx_is_syncing(tx));
 642         ASSERT(dd->dd_phys->dd_head_dataset_obj == 0);
 643 
 644         dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
 645             DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
 646         VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
 647         dmu_buf_will_dirty(dbuf, tx);
 648         dsphys = dbuf->db_data;
 649         bzero(dsphys, sizeof (dsl_dataset_phys_t));
 650         dsphys->ds_dir_obj = dd->dd_object;
 651         dsphys->ds_flags = flags;
 652         dsphys->ds_fsid_guid = unique_create();
 653         (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
 654             sizeof (dsphys->ds_guid));
 655         dsphys->ds_snapnames_zapobj =
 656             zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP,
 657             DMU_OT_NONE, 0, tx);
 658         dsphys->ds_creation_time = gethrestime_sec();
 659         dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg;
 660 
 661         if (origin == NULL) {
 662                 dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx);
 663         } else {
 664                 dsl_dataset_t *ohds; /* head of the origin snapshot */
 665 
 666                 dsphys->ds_prev_snap_obj = origin->ds_object;
 667                 dsphys->ds_prev_snap_txg =
 668                     origin->ds_phys->ds_creation_txg;
 669                 dsphys->ds_referenced_bytes =
 670                     origin->ds_phys->ds_referenced_bytes;
 671                 dsphys->ds_compressed_bytes =
 672                     origin->ds_phys->ds_compressed_bytes;
 673                 dsphys->ds_uncompressed_bytes =
 674                     origin->ds_phys->ds_uncompressed_bytes;
 675                 dsphys->ds_bp = origin->ds_phys->ds_bp;
 676                 dsphys->ds_flags |= origin->ds_phys->ds_flags;
 677 
 678                 dmu_buf_will_dirty(origin->ds_dbuf, tx);
 679                 origin->ds_phys->ds_num_children++;
 680 
 681                 VERIFY0(dsl_dataset_hold_obj(dp,
 682                     origin->ds_dir->dd_phys->dd_head_dataset_obj, FTAG, &ohds));
 683                 dsphys->ds_deadlist_obj = dsl_deadlist_clone(&ohds->ds_deadlist,
 684                     dsphys->ds_prev_snap_txg, dsphys->ds_prev_snap_obj, tx);
 685                 dsl_dataset_rele(ohds, FTAG);
 686 
 687                 if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) {
 688                         if (origin->ds_phys->ds_next_clones_obj == 0) {
 689                                 origin->ds_phys->ds_next_clones_obj =
 690                                     zap_create(mos,
 691                                     DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
 692                         }
 693                         VERIFY0(zap_add_int(mos,
 694                             origin->ds_phys->ds_next_clones_obj, dsobj, tx));
 695                 }
 696 
 697                 dmu_buf_will_dirty(dd->dd_dbuf, tx);
 698                 dd->dd_phys->dd_origin_obj = origin->ds_object;
 699                 if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
 700                         if (origin->ds_dir->dd_phys->dd_clones == 0) {
 701                                 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
 702                                 origin->ds_dir->dd_phys->dd_clones =
 703                                     zap_create(mos,
 704                                     DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
 705                         }
 706                         VERIFY0(zap_add_int(mos,
 707                             origin->ds_dir->dd_phys->dd_clones, dsobj, tx));
 708                 }
 709         }
 710 
 711         if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
 712                 dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
 713 
 714         dmu_buf_rele(dbuf, FTAG);
 715 
 716         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 717         dd->dd_phys->dd_head_dataset_obj = dsobj;
 718 
 719         return (dsobj);
 720 }
 721 
 722 static void
 723 dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
 724 {
 725         objset_t *os;
 726 
 727         VERIFY0(dmu_objset_from_ds(ds, &os));
 728         bzero(&os->os_zil_header, sizeof (os->os_zil_header));
 729         dsl_dataset_dirty(ds, tx);
 730 }
 731 
 732 uint64_t
 733 dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
 734     dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx)
 735 {
 736         dsl_pool_t *dp = pdd->dd_pool;
 737         uint64_t dsobj, ddobj;
 738         dsl_dir_t *dd;
 739 
 740         ASSERT(dmu_tx_is_syncing(tx));
 741         ASSERT(lastname[0] != '@');
 742 
 743         ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
 744         VERIFY0(dsl_dir_hold_obj(dp, ddobj, lastname, FTAG, &dd));
 745 
 746         dsobj = dsl_dataset_create_sync_dd(dd, origin,
 747             flags & ~DS_CREATE_FLAG_NODIRTY, tx);
 748 
 749         dsl_deleg_set_create_perms(dd, tx, cr);
 750 
 751         dsl_dir_rele(dd, FTAG);
 752 
 753         /*
 754          * If we are creating a clone, make sure we zero out any stale
 755          * data from the origin snapshots zil header.
 756          */
 757         if (origin != NULL && !(flags & DS_CREATE_FLAG_NODIRTY)) {
 758                 dsl_dataset_t *ds;
 759 
 760                 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
 761                 dsl_dataset_zero_zil(ds, tx);
 762                 dsl_dataset_rele(ds, FTAG);
 763         }
 764 
 765         return (dsobj);
 766 }
 767 
 768 /*
 769  * The unique space in the head dataset can be calculated by subtracting
 770  * the space used in the most recent snapshot, that is still being used
 771  * in this file system, from the space currently in use.  To figure out
 772  * the space in the most recent snapshot still in use, we need to take
 773  * the total space used in the snapshot and subtract out the space that
 774  * has been freed up since the snapshot was taken.
 775  */
 776 void
 777 dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
 778 {
 779         uint64_t mrs_used;
 780         uint64_t dlused, dlcomp, dluncomp;
 781 
 782         ASSERT(!dsl_dataset_is_snapshot(ds));
 783 
 784         if (ds->ds_phys->ds_prev_snap_obj != 0)
 785                 mrs_used = ds->ds_prev->ds_phys->ds_referenced_bytes;
 786         else
 787                 mrs_used = 0;
 788 
 789         dsl_deadlist_space(&ds->ds_deadlist, &dlused, &dlcomp, &dluncomp);
 790 
 791         ASSERT3U(dlused, <=, mrs_used);
 792         ds->ds_phys->ds_unique_bytes =
 793             ds->ds_phys->ds_referenced_bytes - (mrs_used - dlused);
 794 
 795         if (spa_version(ds->ds_dir->dd_pool->dp_spa) >=
 796             SPA_VERSION_UNIQUE_ACCURATE)
 797                 ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
 798 }
 799 
 800 void
 801 dsl_dataset_remove_from_next_clones(dsl_dataset_t *ds, uint64_t obj,
 802     dmu_tx_t *tx)
 803 {
 804         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
 805         uint64_t count;
 806         int err;
 807 
 808         ASSERT(ds->ds_phys->ds_num_children >= 2);
 809         err = zap_remove_int(mos, ds->ds_phys->ds_next_clones_obj, obj, tx);
 810         /*
 811          * The err should not be ENOENT, but a bug in a previous version
 812          * of the code could cause upgrade_clones_cb() to not set
 813          * ds_next_snap_obj when it should, leading to a missing entry.
 814          * If we knew that the pool was created after
 815          * SPA_VERSION_NEXT_CLONES, we could assert that it isn't
 816          * ENOENT.  However, at least we can check that we don't have
 817          * too many entries in the next_clones_obj even after failing to
 818          * remove this one.
 819          */
 820         if (err != ENOENT)
 821                 VERIFY0(err);
 822         ASSERT0(zap_count(mos, ds->ds_phys->ds_next_clones_obj,
 823             &count));
 824         ASSERT3U(count, <=, ds->ds_phys->ds_num_children - 2);
 825 }
 826 
 827 
 828 blkptr_t *
 829 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
 830 {
 831         return (&ds->ds_phys->ds_bp);
 832 }
 833 
 834 void
 835 dsl_dataset_set_blkptr(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
 836 {
 837         ASSERT(dmu_tx_is_syncing(tx));
 838         /* If it's the meta-objset, set dp_meta_rootbp */
 839         if (ds == NULL) {
 840                 tx->tx_pool->dp_meta_rootbp = *bp;
 841         } else {
 842                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
 843                 ds->ds_phys->ds_bp = *bp;
 844         }
 845 }
 846 
 847 spa_t *
 848 dsl_dataset_get_spa(dsl_dataset_t *ds)
 849 {
 850         return (ds->ds_dir->dd_pool->dp_spa);
 851 }
 852 
 853 void
 854 dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
 855 {
 856         dsl_pool_t *dp;
 857 
 858         if (ds == NULL) /* this is the meta-objset */
 859                 return;
 860 
 861         ASSERT(ds->ds_objset != NULL);
 862 
 863         if (ds->ds_phys->ds_next_snap_obj != 0)
 864                 panic("dirtying snapshot!");
 865 
 866         dp = ds->ds_dir->dd_pool;
 867 
 868         if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg)) {
 869                 /* up the hold count until we can be written out */
 870                 dmu_buf_add_ref(ds->ds_dbuf, ds);
 871         }
 872 }
 873 
 874 boolean_t
 875 dsl_dataset_is_dirty(dsl_dataset_t *ds)
 876 {
 877         for (int t = 0; t < TXG_SIZE; t++) {
 878                 if (txg_list_member(&ds->ds_dir->dd_pool->dp_dirty_datasets,
 879                     ds, t))
 880                         return (B_TRUE);
 881         }
 882         return (B_FALSE);
 883 }
 884 
 885 static int
 886 dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx)
 887 {
 888         uint64_t asize;
 889 
 890         if (!dmu_tx_is_syncing(tx))
 891                 return (0);
 892 
 893         /*
 894          * If there's an fs-only reservation, any blocks that might become
 895          * owned by the snapshot dataset must be accommodated by space
 896          * outside of the reservation.
 897          */
 898         ASSERT(ds->ds_reserved == 0 || DS_UNIQUE_IS_ACCURATE(ds));
 899         asize = MIN(ds->ds_phys->ds_unique_bytes, ds->ds_reserved);
 900         if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE))
 901                 return (SET_ERROR(ENOSPC));
 902 
 903         /*
 904          * Propagate any reserved space for this snapshot to other
 905          * snapshot checks in this sync group.
 906          */
 907         if (asize > 0)
 908                 dsl_dir_willuse_space(ds->ds_dir, asize, tx);
 909 
 910         return (0);
 911 }
 912 
 913 typedef struct dsl_dataset_snapshot_arg {
 914         nvlist_t *ddsa_snaps;
 915         nvlist_t *ddsa_props;
 916         nvlist_t *ddsa_errors;
 917 } dsl_dataset_snapshot_arg_t;
 918 
 919 int
 920 dsl_dataset_snapshot_check_impl(dsl_dataset_t *ds, const char *snapname,
 921     dmu_tx_t *tx, boolean_t recv)
 922 {
 923         int error;
 924         uint64_t value;
 925 
 926         ds->ds_trysnap_txg = tx->tx_txg;
 927 
 928         if (!dmu_tx_is_syncing(tx))
 929                 return (0);
 930 
 931         /*
 932          * We don't allow multiple snapshots of the same txg.  If there
 933          * is already one, try again.
 934          */
 935         if (ds->ds_phys->ds_prev_snap_txg >= tx->tx_txg)
 936                 return (SET_ERROR(EAGAIN));
 937 
 938         /*
 939          * Check for conflicting snapshot name.
 940          */
 941         error = dsl_dataset_snap_lookup(ds, snapname, &value);
 942         if (error == 0)
 943                 return (SET_ERROR(EEXIST));
 944         if (error != ENOENT)
 945                 return (error);
 946 
 947         /*
 948          * We don't allow taking snapshots of inconsistent datasets, such as
 949          * those into which we are currently receiving.  However, if we are
 950          * creating this snapshot as part of a receive, this check will be
 951          * executed atomically with respect to the completion of the receive
 952          * itself but prior to the clearing of DS_FLAG_INCONSISTENT; in this
 953          * case we ignore this, knowing it will be fixed up for us shortly in
 954          * dmu_recv_end_sync().
 955          */
 956         if (!recv && DS_IS_INCONSISTENT(ds))
 957                 return (SET_ERROR(EBUSY));
 958 
 959         error = dsl_dataset_snapshot_reserve_space(ds, tx);
 960         if (error != 0)
 961                 return (error);
 962 
 963         return (0);
 964 }
 965 
 966 static int
 967 dsl_dataset_snapshot_check(void *arg, dmu_tx_t *tx)
 968 {
 969         dsl_dataset_snapshot_arg_t *ddsa = arg;
 970         dsl_pool_t *dp = dmu_tx_pool(tx);
 971         nvpair_t *pair;
 972         int rv = 0;
 973 
 974         for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
 975             pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
 976                 int error = 0;
 977                 dsl_dataset_t *ds;
 978                 char *name, *atp;
 979                 char dsname[MAXNAMELEN];
 980 
 981                 name = nvpair_name(pair);
 982                 if (strlen(name) >= MAXNAMELEN)
 983                         error = SET_ERROR(ENAMETOOLONG);
 984                 if (error == 0) {
 985                         atp = strchr(name, '@');
 986                         if (atp == NULL)
 987                                 error = SET_ERROR(EINVAL);
 988                         if (error == 0)
 989                                 (void) strlcpy(dsname, name, atp - name + 1);
 990                 }
 991                 if (error == 0)
 992                         error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
 993                 if (error == 0) {
 994                         error = dsl_dataset_snapshot_check_impl(ds,
 995                             atp + 1, tx, B_FALSE);
 996                         dsl_dataset_rele(ds, FTAG);
 997                 }
 998 
 999                 if (error != 0) {
1000                         if (ddsa->ddsa_errors != NULL) {
1001                                 fnvlist_add_int32(ddsa->ddsa_errors,
1002                                     name, error);
1003                         }
1004                         rv = error;
1005                 }
1006         }
1007         return (rv);
1008 }
1009 
1010 void
1011 dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
1012     dmu_tx_t *tx)
1013 {
1014         static zil_header_t zero_zil;
1015 
1016         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1017         dmu_buf_t *dbuf;
1018         dsl_dataset_phys_t *dsphys;
1019         uint64_t dsobj, crtxg;
1020         objset_t *mos = dp->dp_meta_objset;
1021         objset_t *os;
1022 
1023         ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
1024 
1025         /*
1026          * If we are on an old pool, the zil must not be active, in which
1027          * case it will be zeroed.  Usually zil_suspend() accomplishes this.
1028          */
1029         ASSERT(spa_version(dmu_tx_pool(tx)->dp_spa) >= SPA_VERSION_FAST_SNAP ||
1030             dmu_objset_from_ds(ds, &os) != 0 ||
1031             bcmp(&os->os_phys->os_zil_header, &zero_zil,
1032             sizeof (zero_zil)) == 0);
1033 
1034 
1035         /*
1036          * The origin's ds_creation_txg has to be < TXG_INITIAL
1037          */
1038         if (strcmp(snapname, ORIGIN_DIR_NAME) == 0)
1039                 crtxg = 1;
1040         else
1041                 crtxg = tx->tx_txg;
1042 
1043         dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1044             DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1045         VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1046         dmu_buf_will_dirty(dbuf, tx);
1047         dsphys = dbuf->db_data;
1048         bzero(dsphys, sizeof (dsl_dataset_phys_t));
1049         dsphys->ds_dir_obj = ds->ds_dir->dd_object;
1050         dsphys->ds_fsid_guid = unique_create();
1051         (void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1052             sizeof (dsphys->ds_guid));
1053         dsphys->ds_prev_snap_obj = ds->ds_phys->ds_prev_snap_obj;
1054         dsphys->ds_prev_snap_txg = ds->ds_phys->ds_prev_snap_txg;
1055         dsphys->ds_next_snap_obj = ds->ds_object;
1056         dsphys->ds_num_children = 1;
1057         dsphys->ds_creation_time = gethrestime_sec();
1058         dsphys->ds_creation_txg = crtxg;
1059         dsphys->ds_deadlist_obj = ds->ds_phys->ds_deadlist_obj;
1060         dsphys->ds_referenced_bytes = ds->ds_phys->ds_referenced_bytes;
1061         dsphys->ds_compressed_bytes = ds->ds_phys->ds_compressed_bytes;
1062         dsphys->ds_uncompressed_bytes = ds->ds_phys->ds_uncompressed_bytes;
1063         dsphys->ds_flags = ds->ds_phys->ds_flags;
1064         dsphys->ds_bp = ds->ds_phys->ds_bp;
1065         dmu_buf_rele(dbuf, FTAG);
1066 
1067         ASSERT3U(ds->ds_prev != 0, ==, ds->ds_phys->ds_prev_snap_obj != 0);
1068         if (ds->ds_prev) {
1069                 uint64_t next_clones_obj =
1070                     ds->ds_prev->ds_phys->ds_next_clones_obj;
1071                 ASSERT(ds->ds_prev->ds_phys->ds_next_snap_obj ==
1072                     ds->ds_object ||
1073                     ds->ds_prev->ds_phys->ds_num_children > 1);
1074                 if (ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) {
1075                         dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1076                         ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==,
1077                             ds->ds_prev->ds_phys->ds_creation_txg);
1078                         ds->ds_prev->ds_phys->ds_next_snap_obj = dsobj;
1079                 } else if (next_clones_obj != 0) {
1080                         dsl_dataset_remove_from_next_clones(ds->ds_prev,
1081                             dsphys->ds_next_snap_obj, tx);
1082                         VERIFY0(zap_add_int(mos,
1083                             next_clones_obj, dsobj, tx));
1084                 }
1085         }
1086 
1087         /*
1088          * If we have a reference-reservation on this dataset, we will
1089          * need to increase the amount of refreservation being charged
1090          * since our unique space is going to zero.
1091          */
1092         if (ds->ds_reserved) {
1093                 int64_t delta;
1094                 ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
1095                 delta = MIN(ds->ds_phys->ds_unique_bytes, ds->ds_reserved);
1096                 dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV,
1097                     delta, 0, 0, tx);
1098         }
1099 
1100         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1101         ds->ds_phys->ds_deadlist_obj = dsl_deadlist_clone(&ds->ds_deadlist,
1102             UINT64_MAX, ds->ds_phys->ds_prev_snap_obj, tx);
1103         dsl_deadlist_close(&ds->ds_deadlist);
1104         dsl_deadlist_open(&ds->ds_deadlist, mos, ds->ds_phys->ds_deadlist_obj);
1105         dsl_deadlist_add_key(&ds->ds_deadlist,
1106             ds->ds_phys->ds_prev_snap_txg, tx);
1107 
1108         ASSERT3U(ds->ds_phys->ds_prev_snap_txg, <, tx->tx_txg);
1109         ds->ds_phys->ds_prev_snap_obj = dsobj;
1110         ds->ds_phys->ds_prev_snap_txg = crtxg;
1111         ds->ds_phys->ds_unique_bytes = 0;
1112         if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1113                 ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1114 
1115         VERIFY0(zap_add(mos, ds->ds_phys->ds_snapnames_zapobj,
1116             snapname, 8, 1, &dsobj, tx));
1117 
1118         if (ds->ds_prev)
1119                 dsl_dataset_rele(ds->ds_prev, ds);
1120         VERIFY0(dsl_dataset_hold_obj(dp,
1121             ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev));
1122 
1123         dsl_scan_ds_snapshotted(ds, tx);
1124 
1125         dsl_dir_snap_cmtime_update(ds->ds_dir);
1126 
1127         spa_history_log_internal_ds(ds->ds_prev, "snapshot", tx, "");
1128 }
1129 
1130 static void
1131 dsl_dataset_snapshot_sync(void *arg, dmu_tx_t *tx)
1132 {
1133         dsl_dataset_snapshot_arg_t *ddsa = arg;
1134         dsl_pool_t *dp = dmu_tx_pool(tx);
1135         nvpair_t *pair;
1136 
1137         for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1138             pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1139                 dsl_dataset_t *ds;
1140                 char *name, *atp;
1141                 char dsname[MAXNAMELEN];
1142 
1143                 name = nvpair_name(pair);
1144                 atp = strchr(name, '@');
1145                 (void) strlcpy(dsname, name, atp - name + 1);
1146                 VERIFY0(dsl_dataset_hold(dp, dsname, FTAG, &ds));
1147 
1148                 dsl_dataset_snapshot_sync_impl(ds, atp + 1, tx);
1149                 if (ddsa->ddsa_props != NULL) {
1150                         dsl_props_set_sync_impl(ds->ds_prev,
1151                             ZPROP_SRC_LOCAL, ddsa->ddsa_props, tx);
1152                 }
1153                 dsl_dataset_rele(ds, FTAG);
1154         }
1155 }
1156 
1157 /*
1158  * The snapshots must all be in the same pool.
1159  * All-or-nothing: if there are any failures, nothing will be modified.
1160  */
1161 int
1162 dsl_dataset_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t *errors)
1163 {
1164         dsl_dataset_snapshot_arg_t ddsa;
1165         nvpair_t *pair;
1166         boolean_t needsuspend;
1167         int error;
1168         spa_t *spa;
1169         char *firstname;
1170         nvlist_t *suspended = NULL;
1171 
1172         pair = nvlist_next_nvpair(snaps, NULL);
1173         if (pair == NULL)
1174                 return (0);
1175         firstname = nvpair_name(pair);
1176 
1177         error = spa_open(firstname, &spa, FTAG);
1178         if (error != 0)
1179                 return (error);
1180         needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1181         spa_close(spa, FTAG);
1182 
1183         if (needsuspend) {
1184                 suspended = fnvlist_alloc();
1185                 for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
1186                     pair = nvlist_next_nvpair(snaps, pair)) {
1187                         char fsname[MAXNAMELEN];
1188                         char *snapname = nvpair_name(pair);
1189                         char *atp;
1190                         void *cookie;
1191 
1192                         atp = strchr(snapname, '@');
1193                         if (atp == NULL) {
1194                                 error = SET_ERROR(EINVAL);
1195                                 break;
1196                         }
1197                         (void) strlcpy(fsname, snapname, atp - snapname + 1);
1198 
1199                         error = zil_suspend(fsname, &cookie);
1200                         if (error != 0)
1201                                 break;
1202                         fnvlist_add_uint64(suspended, fsname,
1203                             (uintptr_t)cookie);
1204                 }
1205         }
1206 
1207         ddsa.ddsa_snaps = snaps;
1208         ddsa.ddsa_props = props;
1209         ddsa.ddsa_errors = errors;
1210 
1211         if (error == 0) {
1212                 error = dsl_sync_task(firstname, dsl_dataset_snapshot_check,
1213                     dsl_dataset_snapshot_sync, &ddsa,
1214                     fnvlist_num_pairs(snaps) * 3);
1215         }
1216 
1217         if (suspended != NULL) {
1218                 for (pair = nvlist_next_nvpair(suspended, NULL); pair != NULL;
1219                     pair = nvlist_next_nvpair(suspended, pair)) {
1220                         zil_resume((void *)(uintptr_t)
1221                             fnvpair_value_uint64(pair));
1222                 }
1223                 fnvlist_free(suspended);
1224         }
1225 
1226         return (error);
1227 }
1228 
1229 typedef struct dsl_dataset_snapshot_tmp_arg {
1230         const char *ddsta_fsname;
1231         const char *ddsta_snapname;
1232         minor_t ddsta_cleanup_minor;
1233         const char *ddsta_htag;
1234 } dsl_dataset_snapshot_tmp_arg_t;
1235 
1236 static int
1237 dsl_dataset_snapshot_tmp_check(void *arg, dmu_tx_t *tx)
1238 {
1239         dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1240         dsl_pool_t *dp = dmu_tx_pool(tx);
1241         dsl_dataset_t *ds;
1242         int error;
1243 
1244         error = dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds);
1245         if (error != 0)
1246                 return (error);
1247 
1248         error = dsl_dataset_snapshot_check_impl(ds, ddsta->ddsta_snapname,
1249             tx, B_FALSE);
1250         if (error != 0) {
1251                 dsl_dataset_rele(ds, FTAG);
1252                 return (error);
1253         }
1254 
1255         if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS) {
1256                 dsl_dataset_rele(ds, FTAG);
1257                 return (SET_ERROR(ENOTSUP));
1258         }
1259         error = dsl_dataset_user_hold_check_one(NULL, ddsta->ddsta_htag,
1260             B_TRUE, tx);
1261         if (error != 0) {
1262                 dsl_dataset_rele(ds, FTAG);
1263                 return (error);
1264         }
1265 
1266         dsl_dataset_rele(ds, FTAG);
1267         return (0);
1268 }
1269 
1270 static void
1271 dsl_dataset_snapshot_tmp_sync(void *arg, dmu_tx_t *tx)
1272 {
1273         dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1274         dsl_pool_t *dp = dmu_tx_pool(tx);
1275         dsl_dataset_t *ds;
1276 
1277         VERIFY0(dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds));
1278 
1279         dsl_dataset_snapshot_sync_impl(ds, ddsta->ddsta_snapname, tx);
1280         dsl_dataset_user_hold_sync_one(ds->ds_prev, ddsta->ddsta_htag,
1281             ddsta->ddsta_cleanup_minor, gethrestime_sec(), tx);
1282         dsl_destroy_snapshot_sync_impl(ds->ds_prev, B_TRUE, tx);
1283 
1284         dsl_dataset_rele(ds, FTAG);
1285 }
1286 
1287 int
1288 dsl_dataset_snapshot_tmp(const char *fsname, const char *snapname,
1289     minor_t cleanup_minor, const char *htag)
1290 {
1291         dsl_dataset_snapshot_tmp_arg_t ddsta;
1292         int error;
1293         spa_t *spa;
1294         boolean_t needsuspend;
1295         void *cookie;
1296 
1297         ddsta.ddsta_fsname = fsname;
1298         ddsta.ddsta_snapname = snapname;
1299         ddsta.ddsta_cleanup_minor = cleanup_minor;
1300         ddsta.ddsta_htag = htag;
1301 
1302         error = spa_open(fsname, &spa, FTAG);
1303         if (error != 0)
1304                 return (error);
1305         needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1306         spa_close(spa, FTAG);
1307 
1308         if (needsuspend) {
1309                 error = zil_suspend(fsname, &cookie);
1310                 if (error != 0)
1311                         return (error);
1312         }
1313 
1314         error = dsl_sync_task(fsname, dsl_dataset_snapshot_tmp_check,
1315             dsl_dataset_snapshot_tmp_sync, &ddsta, 3);
1316 
1317         if (needsuspend)
1318                 zil_resume(cookie);
1319         return (error);
1320 }
1321 
1322 
1323 void
1324 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
1325 {
1326         ASSERT(dmu_tx_is_syncing(tx));
1327         ASSERT(ds->ds_objset != NULL);
1328         ASSERT(ds->ds_phys->ds_next_snap_obj == 0);
1329 
1330         /*
1331          * in case we had to change ds_fsid_guid when we opened it,
1332          * sync it out now.
1333          */
1334         dmu_buf_will_dirty(ds->ds_dbuf, tx);
1335         ds->ds_phys->ds_fsid_guid = ds->ds_fsid_guid;
1336 
1337         dmu_objset_sync(ds->ds_objset, zio, tx);
1338 }
1339 
1340 static void
1341 get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
1342 {
1343         uint64_t count = 0;
1344         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1345         zap_cursor_t zc;
1346         zap_attribute_t za;
1347         nvlist_t *propval = fnvlist_alloc();
1348         nvlist_t *val = fnvlist_alloc();
1349 
1350         ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
1351 
1352         /*
1353          * There may be missing entries in ds_next_clones_obj
1354          * due to a bug in a previous version of the code.
1355          * Only trust it if it has the right number of entries.
1356          */
1357         if (ds->ds_phys->ds_next_clones_obj != 0) {
1358                 ASSERT0(zap_count(mos, ds->ds_phys->ds_next_clones_obj,
1359                     &count));
1360         }
1361         if (count != ds->ds_phys->ds_num_children - 1)
1362                 goto fail;
1363         for (zap_cursor_init(&zc, mos, ds->ds_phys->ds_next_clones_obj);
1364             zap_cursor_retrieve(&zc, &za) == 0;
1365             zap_cursor_advance(&zc)) {
1366                 dsl_dataset_t *clone;
1367                 char buf[ZFS_MAXNAMELEN];
1368                 VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
1369                     za.za_first_integer, FTAG, &clone));
1370                 dsl_dir_name(clone->ds_dir, buf);
1371                 fnvlist_add_boolean(val, buf);
1372                 dsl_dataset_rele(clone, FTAG);
1373         }
1374         zap_cursor_fini(&zc);
1375         fnvlist_add_nvlist(propval, ZPROP_VALUE, val);
1376         fnvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES), propval);
1377 fail:
1378         nvlist_free(val);
1379         nvlist_free(propval);
1380 }
1381 
1382 void
1383 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
1384 {
1385         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1386         uint64_t refd, avail, uobjs, aobjs, ratio;
1387 
1388         ASSERT(dsl_pool_config_held(dp));
1389 
1390         ratio = ds->ds_phys->ds_compressed_bytes == 0 ? 100 :
1391             (ds->ds_phys->ds_uncompressed_bytes * 100 /
1392             ds->ds_phys->ds_compressed_bytes);
1393 
1394         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRATIO, ratio);
1395         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALREFERENCED,
1396             ds->ds_phys->ds_uncompressed_bytes);
1397 
1398         if (dsl_dataset_is_snapshot(ds)) {
1399                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
1400                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
1401                     ds->ds_phys->ds_unique_bytes);
1402                 get_clones_stat(ds, nv);
1403         } else {
1404                 dsl_dir_stats(ds->ds_dir, nv);
1405         }
1406 
1407         dsl_dataset_space(ds, &refd, &avail, &uobjs, &aobjs);
1408         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE, avail);
1409         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED, refd);
1410 
1411         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION,
1412             ds->ds_phys->ds_creation_time);
1413         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG,
1414             ds->ds_phys->ds_creation_txg);
1415         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA,
1416             ds->ds_quota);
1417         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION,
1418             ds->ds_reserved);
1419         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_GUID,
1420             ds->ds_phys->ds_guid);
1421         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_UNIQUE,
1422             ds->ds_phys->ds_unique_bytes);
1423         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_OBJSETID,
1424             ds->ds_object);
1425         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERREFS,
1426             ds->ds_userrefs);
1427         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
1428             DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
1429 
1430         if (ds->ds_phys->ds_prev_snap_obj != 0) {
1431                 uint64_t written, comp, uncomp;
1432                 dsl_pool_t *dp = ds->ds_dir->dd_pool;
1433                 dsl_dataset_t *prev;
1434 
1435                 int err = dsl_dataset_hold_obj(dp,
1436                     ds->ds_phys->ds_prev_snap_obj, FTAG, &prev);
1437                 if (err == 0) {
1438                         err = dsl_dataset_space_written(prev, ds, &written,
1439                             &comp, &uncomp);
1440                         dsl_dataset_rele(prev, FTAG);
1441                         if (err == 0) {
1442                                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
1443                                     written);
1444                         }
1445                 }
1446         }
1447 }
1448 
1449 void
1450 dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat)
1451 {
1452         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1453         ASSERT(dsl_pool_config_held(dp));
1454 
1455         stat->dds_creation_txg = ds->ds_phys->ds_creation_txg;
1456         stat->dds_inconsistent = ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT;
1457         stat->dds_guid = ds->ds_phys->ds_guid;
1458         stat->dds_origin[0] = '\0';
1459         if (dsl_dataset_is_snapshot(ds)) {
1460                 stat->dds_is_snapshot = B_TRUE;
1461                 stat->dds_num_clones = ds->ds_phys->ds_num_children - 1;
1462         } else {
1463                 stat->dds_is_snapshot = B_FALSE;
1464                 stat->dds_num_clones = 0;
1465 
1466                 if (dsl_dir_is_clone(ds->ds_dir)) {
1467                         dsl_dataset_t *ods;
1468 
1469                         VERIFY0(dsl_dataset_hold_obj(dp,
1470                             ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &ods));
1471                         dsl_dataset_name(ods, stat->dds_origin);
1472                         dsl_dataset_rele(ods, FTAG);
1473                 }
1474         }
1475 }
1476 
1477 uint64_t
1478 dsl_dataset_fsid_guid(dsl_dataset_t *ds)
1479 {
1480         return (ds->ds_fsid_guid);
1481 }
1482 
1483 void
1484 dsl_dataset_space(dsl_dataset_t *ds,
1485     uint64_t *refdbytesp, uint64_t *availbytesp,
1486     uint64_t *usedobjsp, uint64_t *availobjsp)
1487 {
1488         *refdbytesp = ds->ds_phys->ds_referenced_bytes;
1489         *availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE);
1490         if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes)
1491                 *availbytesp += ds->ds_reserved - ds->ds_phys->ds_unique_bytes;
1492         if (ds->ds_quota != 0) {
1493                 /*
1494                  * Adjust available bytes according to refquota
1495                  */
1496                 if (*refdbytesp < ds->ds_quota)
1497                         *availbytesp = MIN(*availbytesp,
1498                             ds->ds_quota - *refdbytesp);
1499                 else
1500                         *availbytesp = 0;
1501         }
1502         *usedobjsp = ds->ds_phys->ds_bp.blk_fill;
1503         *availobjsp = DN_MAX_OBJECT - *usedobjsp;
1504 }
1505 
1506 boolean_t
1507 dsl_dataset_modified_since_snap(dsl_dataset_t *ds, dsl_dataset_t *snap)
1508 {
1509         dsl_pool_t *dp = ds->ds_dir->dd_pool;
1510 
1511         ASSERT(dsl_pool_config_held(dp));
1512         if (snap == NULL)
1513                 return (B_FALSE);
1514         if (ds->ds_phys->ds_bp.blk_birth >
1515             snap->ds_phys->ds_creation_txg) {
1516                 objset_t *os, *os_snap;
1517                 /*
1518                  * It may be that only the ZIL differs, because it was
1519                  * reset in the head.  Don't count that as being
1520                  * modified.
1521                  */
1522                 if (dmu_objset_from_ds(ds, &os) != 0)
1523                         return (B_TRUE);
1524                 if (dmu_objset_from_ds(snap, &os_snap) != 0)
1525                         return (B_TRUE);
1526                 return (bcmp(&os->os_phys->os_meta_dnode,
1527                     &os_snap->os_phys->os_meta_dnode,
1528                     sizeof (os->os_phys->os_meta_dnode)) != 0);
1529         }
1530         return (B_FALSE);
1531 }
1532 
1533 typedef struct dsl_dataset_rename_snapshot_arg {
1534         const char *ddrsa_fsname;
1535         const char *ddrsa_oldsnapname;
1536         const char *ddrsa_newsnapname;
1537         boolean_t ddrsa_recursive;
1538         dmu_tx_t *ddrsa_tx;
1539 } dsl_dataset_rename_snapshot_arg_t;
1540 
1541 /* ARGSUSED */
1542 static int
1543 dsl_dataset_rename_snapshot_check_impl(dsl_pool_t *dp,
1544     dsl_dataset_t *hds, void *arg)
1545 {
1546         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1547         int error;
1548         uint64_t val;
1549 
1550         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
1551         if (error != 0) {
1552                 /* ignore nonexistent snapshots */
1553                 return (error == ENOENT ? 0 : error);
1554         }
1555 
1556         /* new name should not exist */
1557         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_newsnapname, &val);
1558         if (error == 0)
1559                 error = SET_ERROR(EEXIST);
1560         else if (error == ENOENT)
1561                 error = 0;
1562 
1563         /* dataset name + 1 for the "@" + the new snapshot name must fit */
1564         if (dsl_dir_namelen(hds->ds_dir) + 1 +
1565             strlen(ddrsa->ddrsa_newsnapname) >= MAXNAMELEN)
1566                 error = SET_ERROR(ENAMETOOLONG);
1567 
1568         return (error);
1569 }
1570 
1571 static int
1572 dsl_dataset_rename_snapshot_check(void *arg, dmu_tx_t *tx)
1573 {
1574         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1575         dsl_pool_t *dp = dmu_tx_pool(tx);
1576         dsl_dataset_t *hds;
1577         int error;
1578 
1579         error = dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds);
1580         if (error != 0)
1581                 return (error);
1582 
1583         if (ddrsa->ddrsa_recursive) {
1584                 error = dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
1585                     dsl_dataset_rename_snapshot_check_impl, ddrsa,
1586                     DS_FIND_CHILDREN);
1587         } else {
1588                 error = dsl_dataset_rename_snapshot_check_impl(dp, hds, ddrsa);
1589         }
1590         dsl_dataset_rele(hds, FTAG);
1591         return (error);
1592 }
1593 
1594 static int
1595 dsl_dataset_rename_snapshot_sync_impl(dsl_pool_t *dp,
1596     dsl_dataset_t *hds, void *arg)
1597 {
1598         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1599         dsl_dataset_t *ds;
1600         uint64_t val;
1601         dmu_tx_t *tx = ddrsa->ddrsa_tx;
1602         int error;
1603 
1604         error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
1605         ASSERT(error == 0 || error == ENOENT);
1606         if (error == ENOENT) {
1607                 /* ignore nonexistent snapshots */
1608                 return (0);
1609         }
1610 
1611         VERIFY0(dsl_dataset_hold_obj(dp, val, FTAG, &ds));
1612 
1613         /* log before we change the name */
1614         spa_history_log_internal_ds(ds, "rename", tx,
1615             "-> @%s", ddrsa->ddrsa_newsnapname);
1616 
1617         VERIFY0(dsl_dataset_snap_remove(hds, ddrsa->ddrsa_oldsnapname, tx));
1618         mutex_enter(&ds->ds_lock);
1619         (void) strcpy(ds->ds_snapname, ddrsa->ddrsa_newsnapname);
1620         mutex_exit(&ds->ds_lock);
1621         VERIFY0(zap_add(dp->dp_meta_objset, hds->ds_phys->ds_snapnames_zapobj,
1622             ds->ds_snapname, 8, 1, &ds->ds_object, tx));
1623 
1624         dsl_dataset_rele(ds, FTAG);
1625         return (0);
1626 }
1627 
1628 static void
1629 dsl_dataset_rename_snapshot_sync(void *arg, dmu_tx_t *tx)
1630 {
1631         dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1632         dsl_pool_t *dp = dmu_tx_pool(tx);
1633         dsl_dataset_t *hds;
1634 
1635         VERIFY0(dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds));
1636         ddrsa->ddrsa_tx = tx;
1637         if (ddrsa->ddrsa_recursive) {
1638                 VERIFY0(dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
1639                     dsl_dataset_rename_snapshot_sync_impl, ddrsa,
1640                     DS_FIND_CHILDREN));
1641         } else {
1642                 VERIFY0(dsl_dataset_rename_snapshot_sync_impl(dp, hds, ddrsa));
1643         }
1644         dsl_dataset_rele(hds, FTAG);
1645 }
1646 
1647 int
1648 dsl_dataset_rename_snapshot(const char *fsname,
1649     const char *oldsnapname, const char *newsnapname, boolean_t recursive)
1650 {
1651         dsl_dataset_rename_snapshot_arg_t ddrsa;
1652 
1653         ddrsa.ddrsa_fsname = fsname;
1654         ddrsa.ddrsa_oldsnapname = oldsnapname;
1655         ddrsa.ddrsa_newsnapname = newsnapname;
1656         ddrsa.ddrsa_recursive = recursive;
1657 
1658         return (dsl_sync_task(fsname, dsl_dataset_rename_snapshot_check,
1659             dsl_dataset_rename_snapshot_sync, &ddrsa, 1));
1660 }
1661 
1662 /*
1663  * If we're doing an ownership handoff, we need to make sure that there is
1664  * only one long hold on the dataset.  We're not allowed to change anything here
1665  * so we don't permanently release the long hold or regular hold here.  We want
1666  * to do this only when syncing to avoid the dataset unexpectedly going away
1667  * when we release the long hold.
1668  */
1669 static int
1670 dsl_dataset_handoff_check(dsl_dataset_t *ds, void *owner, dmu_tx_t *tx)
1671 {
1672         boolean_t held;
1673 
1674         if (!dmu_tx_is_syncing(tx))
1675                 return (0);
1676 
1677         if (owner != NULL) {
1678                 VERIFY3P(ds->ds_owner, ==, owner);
1679                 dsl_dataset_long_rele(ds, owner);
1680         }
1681 
1682         held = dsl_dataset_long_held(ds);
1683 
1684         if (owner != NULL)
1685                 dsl_dataset_long_hold(ds, owner);
1686 
1687         if (held)
1688                 return (SET_ERROR(EBUSY));
1689 
1690         return (0);
1691 }
1692 
1693 typedef struct dsl_dataset_rollback_arg {
1694         const char *ddra_fsname;
1695         void *ddra_owner;
1696         nvlist_t *ddra_result;
1697 } dsl_dataset_rollback_arg_t;
1698 
1699 static int
1700 dsl_dataset_rollback_check(void *arg, dmu_tx_t *tx)
1701 {
1702         dsl_dataset_rollback_arg_t *ddra = arg;
1703         dsl_pool_t *dp = dmu_tx_pool(tx);
1704         dsl_dataset_t *ds;
1705         int64_t unused_refres_delta;
1706         int error;
1707 
1708         error = dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds);
1709         if (error != 0)
1710                 return (error);
1711 
1712         /* must not be a snapshot */
1713         if (dsl_dataset_is_snapshot(ds)) {
1714                 dsl_dataset_rele(ds, FTAG);
1715                 return (SET_ERROR(EINVAL));
1716         }
1717 
1718         /* must have a most recent snapshot */
1719         if (ds->ds_phys->ds_prev_snap_txg < TXG_INITIAL) {
1720                 dsl_dataset_rele(ds, FTAG);
1721                 return (SET_ERROR(EINVAL));
1722         }
1723 
1724         error = dsl_dataset_handoff_check(ds, ddra->ddra_owner, tx);
1725         if (error != 0) {
1726                 dsl_dataset_rele(ds, FTAG);
1727                 return (error);
1728         }
1729 
1730         /*
1731          * Check if the snap we are rolling back to uses more than
1732          * the refquota.
1733          */
1734         if (ds->ds_quota != 0 &&
1735             ds->ds_prev->ds_phys->ds_referenced_bytes > ds->ds_quota) {
1736                 dsl_dataset_rele(ds, FTAG);
1737                 return (SET_ERROR(EDQUOT));
1738         }
1739 
1740         /*
1741          * When we do the clone swap, we will temporarily use more space
1742          * due to the refreservation (the head will no longer have any
1743          * unique space, so the entire amount of the refreservation will need
1744          * to be free).  We will immediately destroy the clone, freeing
1745          * this space, but the freeing happens over many txg's.
1746          */
1747         unused_refres_delta = (int64_t)MIN(ds->ds_reserved,
1748             ds->ds_phys->ds_unique_bytes);
1749 
1750         if (unused_refres_delta > 0 &&
1751             unused_refres_delta >
1752             dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) {
1753                 dsl_dataset_rele(ds, FTAG);
1754                 return (SET_ERROR(ENOSPC));
1755         }
1756 
1757         dsl_dataset_rele(ds, FTAG);
1758         return (0);
1759 }
1760 
1761 static void
1762 dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
1763 {
1764         dsl_dataset_rollback_arg_t *ddra = arg;
1765         dsl_pool_t *dp = dmu_tx_pool(tx);
1766         dsl_dataset_t *ds, *clone;
1767         uint64_t cloneobj;
1768         char namebuf[ZFS_MAXNAMELEN];
1769 
1770         VERIFY0(dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds));
1771 
1772         dsl_dataset_name(ds->ds_prev, namebuf);
1773         fnvlist_add_string(ddra->ddra_result, "target", namebuf);
1774 
1775         cloneobj = dsl_dataset_create_sync(ds->ds_dir, "%rollback",
1776             ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, tx);
1777 
1778         VERIFY0(dsl_dataset_hold_obj(dp, cloneobj, FTAG, &clone));
1779 
1780         dsl_dataset_clone_swap_sync_impl(clone, ds, tx);
1781         dsl_dataset_zero_zil(ds, tx);
1782 
1783         dsl_destroy_head_sync_impl(clone, tx);
1784 
1785         dsl_dataset_rele(clone, FTAG);
1786         dsl_dataset_rele(ds, FTAG);
1787 }
1788 
1789 /*
1790  * Rolls back the given filesystem or volume to the most recent snapshot.
1791  * The name of the most recent snapshot will be returned under key "target"
1792  * in the result nvlist.
1793  *
1794  * If owner != NULL:
1795  * - The existing dataset MUST be owned by the specified owner at entry
1796  * - Upon return, dataset will still be held by the same owner, whether we
1797  *   succeed or not.
1798  *
1799  * This mode is required any time the existing filesystem is mounted.  See
1800  * notes above zfs_suspend_fs() for further details.
1801  */
1802 int
1803 dsl_dataset_rollback(const char *fsname, void *owner, nvlist_t *result)
1804 {
1805         dsl_dataset_rollback_arg_t ddra;
1806 
1807         ddra.ddra_fsname = fsname;
1808         ddra.ddra_owner = owner;
1809         ddra.ddra_result = result;
1810 
1811         return (dsl_sync_task(fsname, dsl_dataset_rollback_check,
1812             dsl_dataset_rollback_sync, &ddra, 1));
1813 }
1814 
1815 struct promotenode {
1816         list_node_t link;
1817         dsl_dataset_t *ds;
1818 };
1819 
1820 typedef struct dsl_dataset_promote_arg {
1821         const char *ddpa_clonename;
1822         dsl_dataset_t *ddpa_clone;
1823         list_t shared_snaps, origin_snaps, clone_snaps;
1824         dsl_dataset_t *origin_origin; /* origin of the origin */
1825         uint64_t used, comp, uncomp, unique, cloneusedsnap, originusedsnap;
1826         char *err_ds;
1827 } dsl_dataset_promote_arg_t;
1828 
1829 static int snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep);
1830 static int promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp,
1831     void *tag);
1832 static void promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag);
1833 
1834 static int
1835 dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
1836 {
1837         dsl_dataset_promote_arg_t *ddpa = arg;
1838         dsl_pool_t *dp = dmu_tx_pool(tx);
1839         dsl_dataset_t *hds;
1840         struct promotenode *snap;
1841         dsl_dataset_t *origin_ds;
1842         int err;
1843         uint64_t unused;
1844 
1845         err = promote_hold(ddpa, dp, FTAG);
1846         if (err != 0)
1847                 return (err);
1848 
1849         hds = ddpa->ddpa_clone;
1850 
1851         if (hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE) {
1852                 promote_rele(ddpa, FTAG);
1853                 return (SET_ERROR(EXDEV));
1854         }
1855 
1856         /*
1857          * Compute and check the amount of space to transfer.  Since this is
1858          * so expensive, don't do the preliminary check.
1859          */
1860         if (!dmu_tx_is_syncing(tx)) {
1861                 promote_rele(ddpa, FTAG);
1862                 return (0);
1863         }
1864 
1865         snap = list_head(&ddpa->shared_snaps);
1866         origin_ds = snap->ds;
1867 
1868         /* compute origin's new unique space */
1869         snap = list_tail(&ddpa->clone_snaps);
1870         ASSERT3U(snap->ds->ds_phys->ds_prev_snap_obj, ==, origin_ds->ds_object);
1871         dsl_deadlist_space_range(&snap->ds->ds_deadlist,
1872             origin_ds->ds_phys->ds_prev_snap_txg, UINT64_MAX,
1873             &ddpa->unique, &unused, &unused);
1874 
1875         /*
1876          * Walk the snapshots that we are moving
1877          *
1878          * Compute space to transfer.  Consider the incremental changes
1879          * to used by each snapshot:
1880          * (my used) = (prev's used) + (blocks born) - (blocks killed)
1881          * So each snapshot gave birth to:
1882          * (blocks born) = (my used) - (prev's used) + (blocks killed)
1883          * So a sequence would look like:
1884          * (uN - u(N-1) + kN) + ... + (u1 - u0 + k1) + (u0 - 0 + k0)
1885          * Which simplifies to:
1886          * uN + kN + kN-1 + ... + k1 + k0
1887          * Note however, if we stop before we reach the ORIGIN we get:
1888          * uN + kN + kN-1 + ... + kM - uM-1
1889          */
1890         ddpa->used = origin_ds->ds_phys->ds_referenced_bytes;
1891         ddpa->comp = origin_ds->ds_phys->ds_compressed_bytes;
1892         ddpa->uncomp = origin_ds->ds_phys->ds_uncompressed_bytes;
1893         for (snap = list_head(&ddpa->shared_snaps); snap;
1894             snap = list_next(&ddpa->shared_snaps, snap)) {
1895                 uint64_t val, dlused, dlcomp, dluncomp;
1896                 dsl_dataset_t *ds = snap->ds;
1897 
1898                 /*
1899                  * If there are long holds, we won't be able to evict
1900                  * the objset.
1901                  */
1902                 if (dsl_dataset_long_held(ds)) {
1903                         err = SET_ERROR(EBUSY);
1904                         goto out;
1905                 }
1906 
1907                 /* Check that the snapshot name does not conflict */
1908                 VERIFY0(dsl_dataset_get_snapname(ds));
1909                 err = dsl_dataset_snap_lookup(hds, ds->ds_snapname, &val);
1910                 if (err == 0) {
1911                         (void) strcpy(ddpa->err_ds, snap->ds->ds_snapname);
1912                         err = SET_ERROR(EEXIST);
1913                         goto out;
1914                 }
1915                 if (err != ENOENT)
1916                         goto out;
1917 
1918                 /* The very first snapshot does not have a deadlist */
1919                 if (ds->ds_phys->ds_prev_snap_obj == 0)
1920                         continue;
1921 
1922                 dsl_deadlist_space(&ds->ds_deadlist,
1923                     &dlused, &dlcomp, &dluncomp);
1924                 ddpa->used += dlused;
1925                 ddpa->comp += dlcomp;
1926                 ddpa->uncomp += dluncomp;
1927         }
1928 
1929         /*
1930          * If we are a clone of a clone then we never reached ORIGIN,
1931          * so we need to subtract out the clone origin's used space.
1932          */
1933         if (ddpa->origin_origin) {
1934                 ddpa->used -= ddpa->origin_origin->ds_phys->ds_referenced_bytes;
1935                 ddpa->comp -= ddpa->origin_origin->ds_phys->ds_compressed_bytes;
1936                 ddpa->uncomp -=
1937                     ddpa->origin_origin->ds_phys->ds_uncompressed_bytes;
1938         }
1939 
1940         /* Check that there is enough space here */
1941         err = dsl_dir_transfer_possible(origin_ds->ds_dir, hds->ds_dir,
1942             ddpa->used);
1943         if (err != 0)
1944                 goto out;
1945 
1946         /*
1947          * Compute the amounts of space that will be used by snapshots
1948          * after the promotion (for both origin and clone).  For each,
1949          * it is the amount of space that will be on all of their
1950          * deadlists (that was not born before their new origin).
1951          */
1952         if (hds->ds_dir->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
1953                 uint64_t space;
1954 
1955                 /*
1956                  * Note, typically this will not be a clone of a clone,
1957                  * so dd_origin_txg will be < TXG_INITIAL, so
1958                  * these snaplist_space() -> dsl_deadlist_space_range()
1959                  * calls will be fast because they do not have to
1960                  * iterate over all bps.
1961                  */
1962                 snap = list_head(&ddpa->origin_snaps);
1963                 err = snaplist_space(&ddpa->shared_snaps,
1964                     snap->ds->ds_dir->dd_origin_txg, &ddpa->cloneusedsnap);
1965                 if (err != 0)
1966                         goto out;
1967 
1968                 err = snaplist_space(&ddpa->clone_snaps,
1969                     snap->ds->ds_dir->dd_origin_txg, &space);
1970                 if (err != 0)
1971                         goto out;
1972                 ddpa->cloneusedsnap += space;
1973         }
1974         if (origin_ds->ds_dir->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
1975                 err = snaplist_space(&ddpa->origin_snaps,
1976                     origin_ds->ds_phys->ds_creation_txg, &ddpa->originusedsnap);
1977                 if (err != 0)
1978                         goto out;
1979         }
1980 
1981 out:
1982         promote_rele(ddpa, FTAG);
1983         return (err);
1984 }
1985 
1986 static void
1987 dsl_dataset_promote_sync(void *arg, dmu_tx_t *tx)
1988 {
1989         dsl_dataset_promote_arg_t *ddpa = arg;
1990         dsl_pool_t *dp = dmu_tx_pool(tx);
1991         dsl_dataset_t *hds;
1992         struct promotenode *snap;
1993         dsl_dataset_t *origin_ds;
1994         dsl_dataset_t *origin_head;
1995         dsl_dir_t *dd;
1996         dsl_dir_t *odd = NULL;
1997         uint64_t oldnext_obj;
1998         int64_t delta;
1999 
2000         VERIFY0(promote_hold(ddpa, dp, FTAG));
2001         hds = ddpa->ddpa_clone;
2002 
2003         ASSERT0(hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE);
2004 
2005         snap = list_head(&ddpa->shared_snaps);
2006         origin_ds = snap->ds;
2007         dd = hds->ds_dir;
2008 
2009         snap = list_head(&ddpa->origin_snaps);
2010         origin_head = snap->ds;
2011 
2012         /*
2013          * We need to explicitly open odd, since origin_ds's dd will be
2014          * changing.
2015          */
2016         VERIFY0(dsl_dir_hold_obj(dp, origin_ds->ds_dir->dd_object,
2017             NULL, FTAG, &odd));
2018 
2019         /* change origin's next snap */
2020         dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
2021         oldnext_obj = origin_ds->ds_phys->ds_next_snap_obj;
2022         snap = list_tail(&ddpa->clone_snaps);
2023         ASSERT3U(snap->ds->ds_phys->ds_prev_snap_obj, ==, origin_ds->ds_object);
2024         origin_ds->ds_phys->ds_next_snap_obj = snap->ds->ds_object;
2025 
2026         /* change the origin's next clone */
2027         if (origin_ds->ds_phys->ds_next_clones_obj) {
2028                 dsl_dataset_remove_from_next_clones(origin_ds,
2029                     snap->ds->ds_object, tx);
2030                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2031                     origin_ds->ds_phys->ds_next_clones_obj,
2032                     oldnext_obj, tx));
2033         }
2034 
2035         /* change origin */
2036         dmu_buf_will_dirty(dd->dd_dbuf, tx);
2037         ASSERT3U(dd->dd_phys->dd_origin_obj, ==, origin_ds->ds_object);
2038         dd->dd_phys->dd_origin_obj = odd->dd_phys->dd_origin_obj;
2039         dd->dd_origin_txg = origin_head->ds_dir->dd_origin_txg;
2040         dmu_buf_will_dirty(odd->dd_dbuf, tx);
2041         odd->dd_phys->dd_origin_obj = origin_ds->ds_object;
2042         origin_head->ds_dir->dd_origin_txg =
2043             origin_ds->ds_phys->ds_creation_txg;
2044 
2045         /* change dd_clone entries */
2046         if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2047                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2048                     odd->dd_phys->dd_clones, hds->ds_object, tx));
2049                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2050                     ddpa->origin_origin->ds_dir->dd_phys->dd_clones,
2051                     hds->ds_object, tx));
2052 
2053                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2054                     ddpa->origin_origin->ds_dir->dd_phys->dd_clones,
2055                     origin_head->ds_object, tx));
2056                 if (dd->dd_phys->dd_clones == 0) {
2057                         dd->dd_phys->dd_clones = zap_create(dp->dp_meta_objset,
2058                             DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
2059                 }
2060                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2061                     dd->dd_phys->dd_clones, origin_head->ds_object, tx));
2062         }
2063 
2064         /* move snapshots to this dir */
2065         for (snap = list_head(&ddpa->shared_snaps); snap;
2066             snap = list_next(&ddpa->shared_snaps, snap)) {
2067                 dsl_dataset_t *ds = snap->ds;
2068 
2069                 /*
2070                  * Property callbacks are registered to a particular
2071                  * dsl_dir.  Since ours is changing, evict the objset
2072                  * so that they will be unregistered from the old dsl_dir.
2073                  */
2074                 if (ds->ds_objset) {
2075                         dmu_objset_evict(ds->ds_objset);
2076                         ds->ds_objset = NULL;
2077                 }
2078 
2079                 /* move snap name entry */
2080                 VERIFY0(dsl_dataset_get_snapname(ds));
2081                 VERIFY0(dsl_dataset_snap_remove(origin_head,
2082                     ds->ds_snapname, tx));
2083                 VERIFY0(zap_add(dp->dp_meta_objset,
2084                     hds->ds_phys->ds_snapnames_zapobj, ds->ds_snapname,
2085                     8, 1, &ds->ds_object, tx));
2086 
2087                 /* change containing dsl_dir */
2088                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
2089                 ASSERT3U(ds->ds_phys->ds_dir_obj, ==, odd->dd_object);
2090                 ds->ds_phys->ds_dir_obj = dd->dd_object;
2091                 ASSERT3P(ds->ds_dir, ==, odd);
2092                 dsl_dir_rele(ds->ds_dir, ds);
2093                 VERIFY0(dsl_dir_hold_obj(dp, dd->dd_object,
2094                     NULL, ds, &ds->ds_dir));
2095 
2096                 /* move any clone references */
2097                 if (ds->ds_phys->ds_next_clones_obj &&
2098                     spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2099                         zap_cursor_t zc;
2100                         zap_attribute_t za;
2101 
2102                         for (zap_cursor_init(&zc, dp->dp_meta_objset,
2103                             ds->ds_phys->ds_next_clones_obj);
2104                             zap_cursor_retrieve(&zc, &za) == 0;
2105                             zap_cursor_advance(&zc)) {
2106                                 dsl_dataset_t *cnds;
2107                                 uint64_t o;
2108 
2109                                 if (za.za_first_integer == oldnext_obj) {
2110                                         /*
2111                                          * We've already moved the
2112                                          * origin's reference.
2113                                          */
2114                                         continue;
2115                                 }
2116 
2117                                 VERIFY0(dsl_dataset_hold_obj(dp,
2118                                     za.za_first_integer, FTAG, &cnds));
2119                                 o = cnds->ds_dir->dd_phys->dd_head_dataset_obj;
2120 
2121                                 VERIFY0(zap_remove_int(dp->dp_meta_objset,
2122                                     odd->dd_phys->dd_clones, o, tx));
2123                                 VERIFY0(zap_add_int(dp->dp_meta_objset,
2124                                     dd->dd_phys->dd_clones, o, tx));
2125                                 dsl_dataset_rele(cnds, FTAG);
2126                         }
2127                         zap_cursor_fini(&zc);
2128                 }
2129 
2130                 ASSERT(!dsl_prop_hascb(ds));
2131         }
2132 
2133         /*
2134          * Change space accounting.
2135          * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either
2136          * both be valid, or both be 0 (resulting in delta == 0).  This
2137          * is true for each of {clone,origin} independently.
2138          */
2139 
2140         delta = ddpa->cloneusedsnap -
2141             dd->dd_phys->dd_used_breakdown[DD_USED_SNAP];
2142         ASSERT3S(delta, >=, 0);
2143         ASSERT3U(ddpa->used, >=, delta);
2144         dsl_dir_diduse_space(dd, DD_USED_SNAP, delta, 0, 0, tx);
2145         dsl_dir_diduse_space(dd, DD_USED_HEAD,
2146             ddpa->used - delta, ddpa->comp, ddpa->uncomp, tx);
2147 
2148         delta = ddpa->originusedsnap -
2149             odd->dd_phys->dd_used_breakdown[DD_USED_SNAP];
2150         ASSERT3S(delta, <=, 0);
2151         ASSERT3U(ddpa->used, >=, -delta);
2152         dsl_dir_diduse_space(odd, DD_USED_SNAP, delta, 0, 0, tx);
2153         dsl_dir_diduse_space(odd, DD_USED_HEAD,
2154             -ddpa->used - delta, -ddpa->comp, -ddpa->uncomp, tx);
2155 
2156         origin_ds->ds_phys->ds_unique_bytes = ddpa->unique;
2157 
2158         /* log history record */
2159         spa_history_log_internal_ds(hds, "promote", tx, "");
2160 
2161         dsl_dir_rele(odd, FTAG);
2162         promote_rele(ddpa, FTAG);
2163 }
2164 
2165 /*
2166  * Make a list of dsl_dataset_t's for the snapshots between first_obj
2167  * (exclusive) and last_obj (inclusive).  The list will be in reverse
2168  * order (last_obj will be the list_head()).  If first_obj == 0, do all
2169  * snapshots back to this dataset's origin.
2170  */
2171 static int
2172 snaplist_make(dsl_pool_t *dp,
2173     uint64_t first_obj, uint64_t last_obj, list_t *l, void *tag)
2174 {
2175         uint64_t obj = last_obj;
2176 
2177         list_create(l, sizeof (struct promotenode),
2178             offsetof(struct promotenode, link));
2179 
2180         while (obj != first_obj) {
2181                 dsl_dataset_t *ds;
2182                 struct promotenode *snap;
2183                 int err;
2184 
2185                 err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
2186                 ASSERT(err != ENOENT);
2187                 if (err != 0)
2188                         return (err);
2189 
2190                 if (first_obj == 0)
2191                         first_obj = ds->ds_dir->dd_phys->dd_origin_obj;
2192 
2193                 snap = kmem_alloc(sizeof (*snap), KM_SLEEP);
2194                 snap->ds = ds;
2195                 list_insert_tail(l, snap);
2196                 obj = ds->ds_phys->ds_prev_snap_obj;
2197         }
2198 
2199         return (0);
2200 }
2201 
2202 static int
2203 snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep)
2204 {
2205         struct promotenode *snap;
2206 
2207         *spacep = 0;
2208         for (snap = list_head(l); snap; snap = list_next(l, snap)) {
2209                 uint64_t used, comp, uncomp;
2210                 dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2211                     mintxg, UINT64_MAX, &used, &comp, &uncomp);
2212                 *spacep += used;
2213         }
2214         return (0);
2215 }
2216 
2217 static void
2218 snaplist_destroy(list_t *l, void *tag)
2219 {
2220         struct promotenode *snap;
2221 
2222         if (l == NULL || !list_link_active(&l->list_head))
2223                 return;
2224 
2225         while ((snap = list_tail(l)) != NULL) {
2226                 list_remove(l, snap);
2227                 dsl_dataset_rele(snap->ds, tag);
2228                 kmem_free(snap, sizeof (*snap));
2229         }
2230         list_destroy(l);
2231 }
2232 
2233 static int
2234 promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp, void *tag)
2235 {
2236         int error;
2237         dsl_dir_t *dd;
2238         struct promotenode *snap;
2239 
2240         error = dsl_dataset_hold(dp, ddpa->ddpa_clonename, tag,
2241             &ddpa->ddpa_clone);
2242         if (error != 0)
2243                 return (error);
2244         dd = ddpa->ddpa_clone->ds_dir;
2245 
2246         if (dsl_dataset_is_snapshot(ddpa->ddpa_clone) ||
2247             !dsl_dir_is_clone(dd)) {
2248                 dsl_dataset_rele(ddpa->ddpa_clone, tag);
2249                 return (SET_ERROR(EINVAL));
2250         }
2251 
2252         error = snaplist_make(dp, 0, dd->dd_phys->dd_origin_obj,
2253             &ddpa->shared_snaps, tag);
2254         if (error != 0)
2255                 goto out;
2256 
2257         error = snaplist_make(dp, 0, ddpa->ddpa_clone->ds_object,
2258             &ddpa->clone_snaps, tag);
2259         if (error != 0)
2260                 goto out;
2261 
2262         snap = list_head(&ddpa->shared_snaps);
2263         ASSERT3U(snap->ds->ds_object, ==, dd->dd_phys->dd_origin_obj);
2264         error = snaplist_make(dp, dd->dd_phys->dd_origin_obj,
2265             snap->ds->ds_dir->dd_phys->dd_head_dataset_obj,
2266             &ddpa->origin_snaps, tag);
2267         if (error != 0)
2268                 goto out;
2269 
2270         if (snap->ds->ds_dir->dd_phys->dd_origin_obj != 0) {
2271                 error = dsl_dataset_hold_obj(dp,
2272                     snap->ds->ds_dir->dd_phys->dd_origin_obj,
2273                     tag, &ddpa->origin_origin);
2274                 if (error != 0)
2275                         goto out;
2276         }
2277 out:
2278         if (error != 0)
2279                 promote_rele(ddpa, tag);
2280         return (error);
2281 }
2282 
2283 static void
2284 promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag)
2285 {
2286         snaplist_destroy(&ddpa->shared_snaps, tag);
2287         snaplist_destroy(&ddpa->clone_snaps, tag);
2288         snaplist_destroy(&ddpa->origin_snaps, tag);
2289         if (ddpa->origin_origin != NULL)
2290                 dsl_dataset_rele(ddpa->origin_origin, tag);
2291         dsl_dataset_rele(ddpa->ddpa_clone, tag);
2292 }
2293 
2294 /*
2295  * Promote a clone.
2296  *
2297  * If it fails due to a conflicting snapshot name, "conflsnap" will be filled
2298  * in with the name.  (It must be at least MAXNAMELEN bytes long.)
2299  */
2300 int
2301 dsl_dataset_promote(const char *name, char *conflsnap)
2302 {
2303         dsl_dataset_promote_arg_t ddpa = { 0 };
2304         uint64_t numsnaps;
2305         int error;
2306         objset_t *os;
2307 
2308         /*
2309          * We will modify space proportional to the number of
2310          * snapshots.  Compute numsnaps.
2311          */
2312         error = dmu_objset_hold(name, FTAG, &os);
2313         if (error != 0)
2314                 return (error);
2315         error = zap_count(dmu_objset_pool(os)->dp_meta_objset,
2316             dmu_objset_ds(os)->ds_phys->ds_snapnames_zapobj, &numsnaps);
2317         dmu_objset_rele(os, FTAG);
2318         if (error != 0)
2319                 return (error);
2320 
2321         ddpa.ddpa_clonename = name;
2322         ddpa.err_ds = conflsnap;
2323 
2324         return (dsl_sync_task(name, dsl_dataset_promote_check,
2325             dsl_dataset_promote_sync, &ddpa, 2 + numsnaps));
2326 }
2327 
2328 int
2329 dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
2330     dsl_dataset_t *origin_head, boolean_t force, void *owner, dmu_tx_t *tx)
2331 {
2332         int64_t unused_refres_delta;
2333 
2334         /* they should both be heads */
2335         if (dsl_dataset_is_snapshot(clone) ||
2336             dsl_dataset_is_snapshot(origin_head))
2337                 return (SET_ERROR(EINVAL));
2338 
2339         /* if we are not forcing, the branch point should be just before them */
2340         if (!force && clone->ds_prev != origin_head->ds_prev)
2341                 return (SET_ERROR(EINVAL));
2342 
2343         /* clone should be the clone (unless they are unrelated) */
2344         if (clone->ds_prev != NULL &&
2345             clone->ds_prev != clone->ds_dir->dd_pool->dp_origin_snap &&
2346             origin_head->ds_dir != clone->ds_prev->ds_dir)
2347                 return (SET_ERROR(EINVAL));
2348 
2349         /* the clone should be a child of the origin */
2350         if (clone->ds_dir->dd_parent != origin_head->ds_dir)
2351                 return (SET_ERROR(EINVAL));
2352 
2353         /* origin_head shouldn't be modified unless 'force' */
2354         if (!force &&
2355             dsl_dataset_modified_since_snap(origin_head, origin_head->ds_prev))
2356                 return (SET_ERROR(ETXTBSY));
2357 
2358         /* origin_head should have no long holds (e.g. is not mounted) */
2359         if (dsl_dataset_handoff_check(origin_head, owner, tx))
2360                 return (SET_ERROR(EBUSY));
2361 
2362         /* check amount of any unconsumed refreservation */
2363         unused_refres_delta =
2364             (int64_t)MIN(origin_head->ds_reserved,
2365             origin_head->ds_phys->ds_unique_bytes) -
2366             (int64_t)MIN(origin_head->ds_reserved,
2367             clone->ds_phys->ds_unique_bytes);
2368 
2369         if (unused_refres_delta > 0 &&
2370             unused_refres_delta >
2371             dsl_dir_space_available(origin_head->ds_dir, NULL, 0, TRUE))
2372                 return (SET_ERROR(ENOSPC));
2373 
2374         /* clone can't be over the head's refquota */
2375         if (origin_head->ds_quota != 0 &&
2376             clone->ds_phys->ds_referenced_bytes > origin_head->ds_quota)
2377                 return (SET_ERROR(EDQUOT));
2378 
2379         return (0);
2380 }
2381 
2382 void
2383 dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
2384     dsl_dataset_t *origin_head, dmu_tx_t *tx)
2385 {
2386         dsl_pool_t *dp = dmu_tx_pool(tx);
2387         int64_t unused_refres_delta;
2388 
2389         ASSERT(clone->ds_reserved == 0);
2390         ASSERT(origin_head->ds_quota == 0 ||
2391             clone->ds_phys->ds_unique_bytes <= origin_head->ds_quota);
2392         ASSERT3P(clone->ds_prev, ==, origin_head->ds_prev);
2393 
2394         dmu_buf_will_dirty(clone->ds_dbuf, tx);
2395         dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
2396 
2397         if (clone->ds_objset != NULL) {
2398                 dmu_objset_evict(clone->ds_objset);
2399                 clone->ds_objset = NULL;
2400         }
2401 
2402         if (origin_head->ds_objset != NULL) {
2403                 dmu_objset_evict(origin_head->ds_objset);
2404                 origin_head->ds_objset = NULL;
2405         }
2406 
2407         unused_refres_delta =
2408             (int64_t)MIN(origin_head->ds_reserved,
2409             origin_head->ds_phys->ds_unique_bytes) -
2410             (int64_t)MIN(origin_head->ds_reserved,
2411             clone->ds_phys->ds_unique_bytes);
2412 
2413         /*
2414          * Reset origin's unique bytes, if it exists.
2415          */
2416         if (clone->ds_prev) {
2417                 dsl_dataset_t *origin = clone->ds_prev;
2418                 uint64_t comp, uncomp;
2419 
2420                 dmu_buf_will_dirty(origin->ds_dbuf, tx);
2421                 dsl_deadlist_space_range(&clone->ds_deadlist,
2422                     origin->ds_phys->ds_prev_snap_txg, UINT64_MAX,
2423                     &origin->ds_phys->ds_unique_bytes, &comp, &uncomp);
2424         }
2425 
2426         /* swap blkptrs */
2427         {
2428                 blkptr_t tmp;
2429                 tmp = origin_head->ds_phys->ds_bp;
2430                 origin_head->ds_phys->ds_bp = clone->ds_phys->ds_bp;
2431                 clone->ds_phys->ds_bp = tmp;
2432         }
2433 
2434         /* set dd_*_bytes */
2435         {
2436                 int64_t dused, dcomp, duncomp;
2437                 uint64_t cdl_used, cdl_comp, cdl_uncomp;
2438                 uint64_t odl_used, odl_comp, odl_uncomp;
2439 
2440                 ASSERT3U(clone->ds_dir->dd_phys->
2441                     dd_used_breakdown[DD_USED_SNAP], ==, 0);
2442 
2443                 dsl_deadlist_space(&clone->ds_deadlist,
2444                     &cdl_used, &cdl_comp, &cdl_uncomp);
2445                 dsl_deadlist_space(&origin_head->ds_deadlist,
2446                     &odl_used, &odl_comp, &odl_uncomp);
2447 
2448                 dused = clone->ds_phys->ds_referenced_bytes + cdl_used -
2449                     (origin_head->ds_phys->ds_referenced_bytes + odl_used);
2450                 dcomp = clone->ds_phys->ds_compressed_bytes + cdl_comp -
2451                     (origin_head->ds_phys->ds_compressed_bytes + odl_comp);
2452                 duncomp = clone->ds_phys->ds_uncompressed_bytes +
2453                     cdl_uncomp -
2454                     (origin_head->ds_phys->ds_uncompressed_bytes + odl_uncomp);
2455 
2456                 dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_HEAD,
2457                     dused, dcomp, duncomp, tx);
2458                 dsl_dir_diduse_space(clone->ds_dir, DD_USED_HEAD,
2459                     -dused, -dcomp, -duncomp, tx);
2460 
2461                 /*
2462                  * The difference in the space used by snapshots is the
2463                  * difference in snapshot space due to the head's
2464                  * deadlist (since that's the only thing that's
2465                  * changing that affects the snapused).
2466                  */
2467                 dsl_deadlist_space_range(&clone->ds_deadlist,
2468                     origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2469                     &cdl_used, &cdl_comp, &cdl_uncomp);
2470                 dsl_deadlist_space_range(&origin_head->ds_deadlist,
2471                     origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2472                     &odl_used, &odl_comp, &odl_uncomp);
2473                 dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
2474                     DD_USED_HEAD, DD_USED_SNAP, tx);
2475         }
2476 
2477         /* swap ds_*_bytes */
2478         SWITCH64(origin_head->ds_phys->ds_referenced_bytes,
2479             clone->ds_phys->ds_referenced_bytes);
2480         SWITCH64(origin_head->ds_phys->ds_compressed_bytes,
2481             clone->ds_phys->ds_compressed_bytes);
2482         SWITCH64(origin_head->ds_phys->ds_uncompressed_bytes,
2483             clone->ds_phys->ds_uncompressed_bytes);
2484         SWITCH64(origin_head->ds_phys->ds_unique_bytes,
2485             clone->ds_phys->ds_unique_bytes);
2486 
2487         /* apply any parent delta for change in unconsumed refreservation */
2488         dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_REFRSRV,
2489             unused_refres_delta, 0, 0, tx);
2490 
2491         /*
2492          * Swap deadlists.
2493          */
2494         dsl_deadlist_close(&clone->ds_deadlist);
2495         dsl_deadlist_close(&origin_head->ds_deadlist);
2496         SWITCH64(origin_head->ds_phys->ds_deadlist_obj,
2497             clone->ds_phys->ds_deadlist_obj);
2498         dsl_deadlist_open(&clone->ds_deadlist, dp->dp_meta_objset,
2499             clone->ds_phys->ds_deadlist_obj);
2500         dsl_deadlist_open(&origin_head->ds_deadlist, dp->dp_meta_objset,
2501             origin_head->ds_phys->ds_deadlist_obj);
2502 
2503         dsl_scan_ds_clone_swapped(origin_head, clone, tx);
2504 
2505         spa_history_log_internal_ds(clone, "clone swap", tx,
2506             "parent=%s", origin_head->ds_dir->dd_myname);
2507 }
2508 
2509 /*
2510  * Given a pool name and a dataset object number in that pool,
2511  * return the name of that dataset.
2512  */
2513 int
2514 dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf)
2515 {
2516         dsl_pool_t *dp;
2517         dsl_dataset_t *ds;
2518         int error;
2519 
2520         error = dsl_pool_hold(pname, FTAG, &dp);
2521         if (error != 0)
2522                 return (error);
2523 
2524         error = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
2525         if (error == 0) {
2526                 dsl_dataset_name(ds, buf);
2527                 dsl_dataset_rele(ds, FTAG);
2528         }
2529         dsl_pool_rele(dp, FTAG);
2530 
2531         return (error);
2532 }
2533 
2534 int
2535 dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota,
2536     uint64_t asize, uint64_t inflight, uint64_t *used, uint64_t *ref_rsrv)
2537 {
2538         int error = 0;
2539 
2540         ASSERT3S(asize, >, 0);
2541 
2542         /*
2543          * *ref_rsrv is the portion of asize that will come from any
2544          * unconsumed refreservation space.
2545          */
2546         *ref_rsrv = 0;
2547 
2548         mutex_enter(&ds->ds_lock);
2549         /*
2550          * Make a space adjustment for reserved bytes.
2551          */
2552         if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes) {
2553                 ASSERT3U(*used, >=,
2554                     ds->ds_reserved - ds->ds_phys->ds_unique_bytes);
2555                 *used -= (ds->ds_reserved - ds->ds_phys->ds_unique_bytes);
2556                 *ref_rsrv =
2557                     asize - MIN(asize, parent_delta(ds, asize + inflight));
2558         }
2559 
2560         if (!check_quota || ds->ds_quota == 0) {
2561                 mutex_exit(&ds->ds_lock);
2562                 return (0);
2563         }
2564         /*
2565          * If they are requesting more space, and our current estimate
2566          * is over quota, they get to try again unless the actual
2567          * on-disk is over quota and there are no pending changes (which
2568          * may free up space for us).
2569          */
2570         if (ds->ds_phys->ds_referenced_bytes + inflight >= ds->ds_quota) {
2571                 if (inflight > 0 ||
2572                     ds->ds_phys->ds_referenced_bytes < ds->ds_quota)
2573                         error = SET_ERROR(ERESTART);
2574                 else
2575                         error = SET_ERROR(EDQUOT);
2576         }
2577         mutex_exit(&ds->ds_lock);
2578 
2579         return (error);
2580 }
2581 
2582 typedef struct dsl_dataset_set_qr_arg {
2583         const char *ddsqra_name;
2584         zprop_source_t ddsqra_source;
2585         uint64_t ddsqra_value;
2586 } dsl_dataset_set_qr_arg_t;
2587 
2588 
2589 /* ARGSUSED */
2590 static int
2591 dsl_dataset_set_refquota_check(void *arg, dmu_tx_t *tx)
2592 {
2593         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2594         dsl_pool_t *dp = dmu_tx_pool(tx);
2595         dsl_dataset_t *ds;
2596         int error;
2597         uint64_t newval;
2598 
2599         if (spa_version(dp->dp_spa) < SPA_VERSION_REFQUOTA)
2600                 return (SET_ERROR(ENOTSUP));
2601 
2602         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
2603         if (error != 0)
2604                 return (error);
2605 
2606         if (dsl_dataset_is_snapshot(ds)) {
2607                 dsl_dataset_rele(ds, FTAG);
2608                 return (SET_ERROR(EINVAL));
2609         }
2610 
2611         error = dsl_prop_predict(ds->ds_dir,
2612             zfs_prop_to_name(ZFS_PROP_REFQUOTA),
2613             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
2614         if (error != 0) {
2615                 dsl_dataset_rele(ds, FTAG);
2616                 return (error);
2617         }
2618 
2619         if (newval == 0) {
2620                 dsl_dataset_rele(ds, FTAG);
2621                 return (0);
2622         }
2623 
2624         if (newval < ds->ds_phys->ds_referenced_bytes ||
2625             newval < ds->ds_reserved) {
2626                 dsl_dataset_rele(ds, FTAG);
2627                 return (SET_ERROR(ENOSPC));
2628         }
2629 
2630         dsl_dataset_rele(ds, FTAG);
2631         return (0);
2632 }
2633 
2634 static void
2635 dsl_dataset_set_refquota_sync(void *arg, dmu_tx_t *tx)
2636 {
2637         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2638         dsl_pool_t *dp = dmu_tx_pool(tx);
2639         dsl_dataset_t *ds;
2640         uint64_t newval;
2641 
2642         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
2643 
2644         dsl_prop_set_sync_impl(ds,
2645             zfs_prop_to_name(ZFS_PROP_REFQUOTA),
2646             ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
2647             &ddsqra->ddsqra_value, tx);
2648 
2649         VERIFY0(dsl_prop_get_int_ds(ds,
2650             zfs_prop_to_name(ZFS_PROP_REFQUOTA), &newval));
2651 
2652         if (ds->ds_quota != newval) {
2653                 dmu_buf_will_dirty(ds->ds_dbuf, tx);
2654                 ds->ds_quota = newval;
2655         }
2656         dsl_dataset_rele(ds, FTAG);
2657 }
2658 
2659 int
2660 dsl_dataset_set_refquota(const char *dsname, zprop_source_t source,
2661     uint64_t refquota)
2662 {
2663         dsl_dataset_set_qr_arg_t ddsqra;
2664 
2665         ddsqra.ddsqra_name = dsname;
2666         ddsqra.ddsqra_source = source;
2667         ddsqra.ddsqra_value = refquota;
2668 
2669         return (dsl_sync_task(dsname, dsl_dataset_set_refquota_check,
2670             dsl_dataset_set_refquota_sync, &ddsqra, 0));
2671 }
2672 
2673 static int
2674 dsl_dataset_set_refreservation_check(void *arg, dmu_tx_t *tx)
2675 {
2676         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2677         dsl_pool_t *dp = dmu_tx_pool(tx);
2678         dsl_dataset_t *ds;
2679         int error;
2680         uint64_t newval, unique;
2681 
2682         if (spa_version(dp->dp_spa) < SPA_VERSION_REFRESERVATION)
2683                 return (SET_ERROR(ENOTSUP));
2684 
2685         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
2686         if (error != 0)
2687                 return (error);
2688 
2689         if (dsl_dataset_is_snapshot(ds)) {
2690                 dsl_dataset_rele(ds, FTAG);
2691                 return (SET_ERROR(EINVAL));
2692         }
2693 
2694         error = dsl_prop_predict(ds->ds_dir,
2695             zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
2696             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
2697         if (error != 0) {
2698                 dsl_dataset_rele(ds, FTAG);
2699                 return (error);
2700         }
2701 
2702         /*
2703          * If we are doing the preliminary check in open context, the
2704          * space estimates may be inaccurate.
2705          */
2706         if (!dmu_tx_is_syncing(tx)) {
2707                 dsl_dataset_rele(ds, FTAG);
2708                 return (0);
2709         }
2710 
2711         mutex_enter(&ds->ds_lock);
2712         if (!DS_UNIQUE_IS_ACCURATE(ds))
2713                 dsl_dataset_recalc_head_uniq(ds);
2714         unique = ds->ds_phys->ds_unique_bytes;
2715         mutex_exit(&ds->ds_lock);
2716 
2717         if (MAX(unique, newval) > MAX(unique, ds->ds_reserved)) {
2718                 uint64_t delta = MAX(unique, newval) -
2719                     MAX(unique, ds->ds_reserved);
2720 
2721                 if (delta >
2722                     dsl_dir_space_available(ds->ds_dir, NULL, 0, B_TRUE) ||
2723                     (ds->ds_quota > 0 && newval > ds->ds_quota)) {
2724                         dsl_dataset_rele(ds, FTAG);
2725                         return (SET_ERROR(ENOSPC));
2726                 }
2727         }
2728 
2729         dsl_dataset_rele(ds, FTAG);
2730         return (0);
2731 }
2732 
2733 void
2734 dsl_dataset_set_refreservation_sync_impl(dsl_dataset_t *ds,
2735     zprop_source_t source, uint64_t value, dmu_tx_t *tx)
2736 {
2737         uint64_t newval;
2738         uint64_t unique;
2739         int64_t delta;
2740 
2741         dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
2742             source, sizeof (value), 1, &value, tx);
2743 
2744         VERIFY0(dsl_prop_get_int_ds(ds,
2745             zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &newval));
2746 
2747         dmu_buf_will_dirty(ds->ds_dbuf, tx);
2748         mutex_enter(&ds->ds_dir->dd_lock);
2749         mutex_enter(&ds->ds_lock);
2750         ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
2751         unique = ds->ds_phys->ds_unique_bytes;
2752         delta = MAX(0, (int64_t)(newval - unique)) -
2753             MAX(0, (int64_t)(ds->ds_reserved - unique));
2754         ds->ds_reserved = newval;
2755         mutex_exit(&ds->ds_lock);
2756 
2757         dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx);
2758         mutex_exit(&ds->ds_dir->dd_lock);
2759 }
2760 
2761 static void
2762 dsl_dataset_set_refreservation_sync(void *arg, dmu_tx_t *tx)
2763 {
2764         dsl_dataset_set_qr_arg_t *ddsqra = arg;
2765         dsl_pool_t *dp = dmu_tx_pool(tx);
2766         dsl_dataset_t *ds;
2767 
2768         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
2769         dsl_dataset_set_refreservation_sync_impl(ds,
2770             ddsqra->ddsqra_source, ddsqra->ddsqra_value, tx);
2771         dsl_dataset_rele(ds, FTAG);
2772 }
2773 
2774 int
2775 dsl_dataset_set_refreservation(const char *dsname, zprop_source_t source,
2776     uint64_t refreservation)
2777 {
2778         dsl_dataset_set_qr_arg_t ddsqra;
2779 
2780         ddsqra.ddsqra_name = dsname;
2781         ddsqra.ddsqra_source = source;
2782         ddsqra.ddsqra_value = refreservation;
2783 
2784         return (dsl_sync_task(dsname, dsl_dataset_set_refreservation_check,
2785             dsl_dataset_set_refreservation_sync, &ddsqra, 0));
2786 }
2787 
2788 /*
2789  * Return (in *usedp) the amount of space written in new that is not
2790  * present in oldsnap.  New may be a snapshot or the head.  Old must be
2791  * a snapshot before new, in new's filesystem (or its origin).  If not then
2792  * fail and return EINVAL.
2793  *
2794  * The written space is calculated by considering two components:  First, we
2795  * ignore any freed space, and calculate the written as new's used space
2796  * minus old's used space.  Next, we add in the amount of space that was freed
2797  * between the two snapshots, thus reducing new's used space relative to old's.
2798  * Specifically, this is the space that was born before old->ds_creation_txg,
2799  * and freed before new (ie. on new's deadlist or a previous deadlist).
2800  *
2801  * space freed                         [---------------------]
2802  * snapshots                       ---O-------O--------O-------O------
2803  *                                         oldsnap            new
2804  */
2805 int
2806 dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
2807     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
2808 {
2809         int err = 0;
2810         uint64_t snapobj;
2811         dsl_pool_t *dp = new->ds_dir->dd_pool;
2812 
2813         ASSERT(dsl_pool_config_held(dp));
2814 
2815         *usedp = 0;
2816         *usedp += new->ds_phys->ds_referenced_bytes;
2817         *usedp -= oldsnap->ds_phys->ds_referenced_bytes;
2818 
2819         *compp = 0;
2820         *compp += new->ds_phys->ds_compressed_bytes;
2821         *compp -= oldsnap->ds_phys->ds_compressed_bytes;
2822 
2823         *uncompp = 0;
2824         *uncompp += new->ds_phys->ds_uncompressed_bytes;
2825         *uncompp -= oldsnap->ds_phys->ds_uncompressed_bytes;
2826 
2827         snapobj = new->ds_object;
2828         while (snapobj != oldsnap->ds_object) {
2829                 dsl_dataset_t *snap;
2830                 uint64_t used, comp, uncomp;
2831 
2832                 if (snapobj == new->ds_object) {
2833                         snap = new;
2834                 } else {
2835                         err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
2836                         if (err != 0)
2837                                 break;
2838                 }
2839 
2840                 if (snap->ds_phys->ds_prev_snap_txg ==
2841                     oldsnap->ds_phys->ds_creation_txg) {
2842                         /*
2843                          * The blocks in the deadlist can not be born after
2844                          * ds_prev_snap_txg, so get the whole deadlist space,
2845                          * which is more efficient (especially for old-format
2846                          * deadlists).  Unfortunately the deadlist code
2847                          * doesn't have enough information to make this
2848                          * optimization itself.
2849                          */
2850                         dsl_deadlist_space(&snap->ds_deadlist,
2851                             &used, &comp, &uncomp);
2852                 } else {
2853                         dsl_deadlist_space_range(&snap->ds_deadlist,
2854                             0, oldsnap->ds_phys->ds_creation_txg,
2855                             &used, &comp, &uncomp);
2856                 }
2857                 *usedp += used;
2858                 *compp += comp;
2859                 *uncompp += uncomp;
2860 
2861                 /*
2862                  * If we get to the beginning of the chain of snapshots
2863                  * (ds_prev_snap_obj == 0) before oldsnap, then oldsnap
2864                  * was not a snapshot of/before new.
2865                  */
2866                 snapobj = snap->ds_phys->ds_prev_snap_obj;
2867                 if (snap != new)
2868                         dsl_dataset_rele(snap, FTAG);
2869                 if (snapobj == 0) {
2870                         err = SET_ERROR(EINVAL);
2871                         break;
2872                 }
2873 
2874         }
2875         return (err);
2876 }
2877 
2878 /*
2879  * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
2880  * lastsnap, and all snapshots in between are deleted.
2881  *
2882  * blocks that would be freed            [---------------------------]
2883  * snapshots                       ---O-------O--------O-------O--------O
2884  *                                        firstsnap        lastsnap
2885  *
2886  * This is the set of blocks that were born after the snap before firstsnap,
2887  * (birth > firstsnap->prev_snap_txg) and died before the snap after the
2888  * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
2889  * We calculate this by iterating over the relevant deadlists (from the snap
2890  * after lastsnap, backward to the snap after firstsnap), summing up the
2891  * space on the deadlist that was born after the snap before firstsnap.
2892  */
2893 int
2894 dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
2895     dsl_dataset_t *lastsnap,
2896     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
2897 {
2898         int err = 0;
2899         uint64_t snapobj;
2900         dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
2901 
2902         ASSERT(dsl_dataset_is_snapshot(firstsnap));
2903         ASSERT(dsl_dataset_is_snapshot(lastsnap));
2904 
2905         /*
2906          * Check that the snapshots are in the same dsl_dir, and firstsnap
2907          * is before lastsnap.
2908          */
2909         if (firstsnap->ds_dir != lastsnap->ds_dir ||
2910             firstsnap->ds_phys->ds_creation_txg >
2911             lastsnap->ds_phys->ds_creation_txg)
2912                 return (SET_ERROR(EINVAL));
2913 
2914         *usedp = *compp = *uncompp = 0;
2915 
2916         snapobj = lastsnap->ds_phys->ds_next_snap_obj;
2917         while (snapobj != firstsnap->ds_object) {
2918                 dsl_dataset_t *ds;
2919                 uint64_t used, comp, uncomp;
2920 
2921                 err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
2922                 if (err != 0)
2923                         break;
2924 
2925                 dsl_deadlist_space_range(&ds->ds_deadlist,
2926                     firstsnap->ds_phys->ds_prev_snap_txg, UINT64_MAX,
2927                     &used, &comp, &uncomp);
2928                 *usedp += used;
2929                 *compp += comp;
2930                 *uncompp += uncomp;
2931 
2932                 snapobj = ds->ds_phys->ds_prev_snap_obj;
2933                 ASSERT3U(snapobj, !=, 0);
2934                 dsl_dataset_rele(ds, FTAG);
2935         }
2936         return (err);
2937 }
2938 
2939 /*
2940  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
2941  * For example, they could both be snapshots of the same filesystem, and
2942  * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
2943  * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
2944  * filesystem.  Or 'earlier' could be the origin's origin.
2945  */
2946 boolean_t
2947 dsl_dataset_is_before(dsl_dataset_t *later, dsl_dataset_t *earlier)
2948 {
2949         dsl_pool_t *dp = later->ds_dir->dd_pool;
2950         int error;
2951         boolean_t ret;
2952 
2953         ASSERT(dsl_pool_config_held(dp));
2954 
2955         if (earlier->ds_phys->ds_creation_txg >=
2956             later->ds_phys->ds_creation_txg)
2957                 return (B_FALSE);
2958 
2959         if (later->ds_dir == earlier->ds_dir)
2960                 return (B_TRUE);
2961         if (!dsl_dir_is_clone(later->ds_dir))
2962                 return (B_FALSE);
2963 
2964         if (later->ds_dir->dd_phys->dd_origin_obj == earlier->ds_object)
2965                 return (B_TRUE);
2966         dsl_dataset_t *origin;
2967         error = dsl_dataset_hold_obj(dp,
2968             later->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin);
2969         if (error != 0)
2970                 return (B_FALSE);
2971         ret = dsl_dataset_is_before(origin, earlier);
2972         dsl_dataset_rele(origin, FTAG);
2973         return (ret);
2974 }
2975 
2976 
2977 void
2978 dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx)
2979 {
2980         objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
2981         dmu_object_zapify(mos, ds->ds_object, DMU_OT_DSL_DATASET, tx);
2982 }