1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
  24  * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
  25  * Copyright (c) 2013, Joyent, Inc. All rights reserved.
  26  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  27  * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
  28  */
  29 
  30 /* Portions Copyright 2010 Robert Milkowski */
  31 
  32 #include <sys/cred.h>
  33 #include <sys/zfs_context.h>
  34 #include <sys/dmu_objset.h>
  35 #include <sys/dsl_dir.h>
  36 #include <sys/dsl_dataset.h>
  37 #include <sys/dsl_prop.h>
  38 #include <sys/dsl_pool.h>
  39 #include <sys/dsl_synctask.h>
  40 #include <sys/dsl_deleg.h>
  41 #include <sys/dnode.h>
  42 #include <sys/dbuf.h>
  43 #include <sys/zvol.h>
  44 #include <sys/dmu_tx.h>
  45 #include <sys/zap.h>
  46 #include <sys/zil.h>
  47 #include <sys/dmu_impl.h>
  48 #include <sys/zfs_ioctl.h>
  49 #include <sys/sa.h>
  50 #include <sys/zfs_onexit.h>
  51 #include <sys/dsl_destroy.h>
  52 
  53 /*
  54  * Needed to close a window in dnode_move() that allows the objset to be freed
  55  * before it can be safely accessed.
  56  */
  57 krwlock_t os_lock;
  58 
  59 void
  60 dmu_objset_init(void)
  61 {
  62         rw_init(&os_lock, NULL, RW_DEFAULT, NULL);
  63 }
  64 
  65 void
  66 dmu_objset_fini(void)
  67 {
  68         rw_destroy(&os_lock);
  69 }
  70 
  71 spa_t *
  72 dmu_objset_spa(objset_t *os)
  73 {
  74         return (os->os_spa);
  75 }
  76 
  77 zilog_t *
  78 dmu_objset_zil(objset_t *os)
  79 {
  80         return (os->os_zil);
  81 }
  82 
  83 dsl_pool_t *
  84 dmu_objset_pool(objset_t *os)
  85 {
  86         dsl_dataset_t *ds;
  87 
  88         if ((ds = os->os_dsl_dataset) != NULL && ds->ds_dir)
  89                 return (ds->ds_dir->dd_pool);
  90         else
  91                 return (spa_get_dsl(os->os_spa));
  92 }
  93 
  94 dsl_dataset_t *
  95 dmu_objset_ds(objset_t *os)
  96 {
  97         return (os->os_dsl_dataset);
  98 }
  99 
 100 dmu_objset_type_t
 101 dmu_objset_type(objset_t *os)
 102 {
 103         return (os->os_phys->os_type);
 104 }
 105 
 106 void
 107 dmu_objset_name(objset_t *os, char *buf)
 108 {
 109         dsl_dataset_name(os->os_dsl_dataset, buf);
 110 }
 111 
 112 uint64_t
 113 dmu_objset_id(objset_t *os)
 114 {
 115         dsl_dataset_t *ds = os->os_dsl_dataset;
 116 
 117         return (ds ? ds->ds_object : 0);
 118 }
 119 
 120 zfs_sync_type_t
 121 dmu_objset_syncprop(objset_t *os)
 122 {
 123         return (os->os_sync);
 124 }
 125 
 126 zfs_logbias_op_t
 127 dmu_objset_logbias(objset_t *os)
 128 {
 129         return (os->os_logbias);
 130 }
 131 
 132 static void
 133 checksum_changed_cb(void *arg, uint64_t newval)
 134 {
 135         objset_t *os = arg;
 136 
 137         /*
 138          * Inheritance should have been done by now.
 139          */
 140         ASSERT(newval != ZIO_CHECKSUM_INHERIT);
 141 
 142         os->os_checksum = zio_checksum_select(newval, ZIO_CHECKSUM_ON_VALUE);
 143 }
 144 
 145 static void
 146 compression_changed_cb(void *arg, uint64_t newval)
 147 {
 148         objset_t *os = arg;
 149 
 150         /*
 151          * Inheritance and range checking should have been done by now.
 152          */
 153         ASSERT(newval != ZIO_COMPRESS_INHERIT);
 154 
 155         os->os_compress = zio_compress_select(os->os_spa, newval,
 156             ZIO_COMPRESS_ON);
 157 }
 158 
 159 static void
 160 copies_changed_cb(void *arg, uint64_t newval)
 161 {
 162         objset_t *os = arg;
 163 
 164         /*
 165          * Inheritance and range checking should have been done by now.
 166          */
 167         ASSERT(newval > 0);
 168         ASSERT(newval <= spa_max_replication(os->os_spa));
 169 
 170         os->os_copies = newval;
 171 }
 172 
 173 static void
 174 dedup_changed_cb(void *arg, uint64_t newval)
 175 {
 176         objset_t *os = arg;
 177         spa_t *spa = os->os_spa;
 178         enum zio_checksum checksum;
 179 
 180         /*
 181          * Inheritance should have been done by now.
 182          */
 183         ASSERT(newval != ZIO_CHECKSUM_INHERIT);
 184 
 185         checksum = zio_checksum_dedup_select(spa, newval, ZIO_CHECKSUM_OFF);
 186 
 187         os->os_dedup_checksum = checksum & ZIO_CHECKSUM_MASK;
 188         os->os_dedup_verify = !!(checksum & ZIO_CHECKSUM_VERIFY);
 189 }
 190 
 191 static void
 192 primary_cache_changed_cb(void *arg, uint64_t newval)
 193 {
 194         objset_t *os = arg;
 195 
 196         /*
 197          * Inheritance and range checking should have been done by now.
 198          */
 199         ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
 200             newval == ZFS_CACHE_METADATA);
 201 
 202         os->os_primary_cache = newval;
 203 }
 204 
 205 static void
 206 secondary_cache_changed_cb(void *arg, uint64_t newval)
 207 {
 208         objset_t *os = arg;
 209 
 210         /*
 211          * Inheritance and range checking should have been done by now.
 212          */
 213         ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
 214             newval == ZFS_CACHE_METADATA);
 215 
 216         os->os_secondary_cache = newval;
 217 }
 218 
 219 static void
 220 sync_changed_cb(void *arg, uint64_t newval)
 221 {
 222         objset_t *os = arg;
 223 
 224         /*
 225          * Inheritance and range checking should have been done by now.
 226          */
 227         ASSERT(newval == ZFS_SYNC_STANDARD || newval == ZFS_SYNC_ALWAYS ||
 228             newval == ZFS_SYNC_DISABLED);
 229 
 230         os->os_sync = newval;
 231         if (os->os_zil)
 232                 zil_set_sync(os->os_zil, newval);
 233 }
 234 
 235 static void
 236 redundant_metadata_changed_cb(void *arg, uint64_t newval)
 237 {
 238         objset_t *os = arg;
 239 
 240         /*
 241          * Inheritance and range checking should have been done by now.
 242          */
 243         ASSERT(newval == ZFS_REDUNDANT_METADATA_ALL ||
 244             newval == ZFS_REDUNDANT_METADATA_MOST);
 245 
 246         os->os_redundant_metadata = newval;
 247 }
 248 
 249 static void
 250 logbias_changed_cb(void *arg, uint64_t newval)
 251 {
 252         objset_t *os = arg;
 253 
 254         ASSERT(newval == ZFS_LOGBIAS_LATENCY ||
 255             newval == ZFS_LOGBIAS_THROUGHPUT);
 256         os->os_logbias = newval;
 257         if (os->os_zil)
 258                 zil_set_logbias(os->os_zil, newval);
 259 }
 260 
 261 static void
 262 recordsize_changed_cb(void *arg, uint64_t newval)
 263 {
 264         objset_t *os = arg;
 265 
 266         os->os_recordsize = newval;
 267 }
 268 
 269 void
 270 dmu_objset_byteswap(void *buf, size_t size)
 271 {
 272         objset_phys_t *osp = buf;
 273 
 274         ASSERT(size == OBJSET_OLD_PHYS_SIZE || size == sizeof (objset_phys_t));
 275         dnode_byteswap(&osp->os_meta_dnode);
 276         byteswap_uint64_array(&osp->os_zil_header, sizeof (zil_header_t));
 277         osp->os_type = BSWAP_64(osp->os_type);
 278         osp->os_flags = BSWAP_64(osp->os_flags);
 279         if (size == sizeof (objset_phys_t)) {
 280                 dnode_byteswap(&osp->os_userused_dnode);
 281                 dnode_byteswap(&osp->os_groupused_dnode);
 282         }
 283 }
 284 
 285 int
 286 dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 287     objset_t **osp)
 288 {
 289         objset_t *os;
 290         int i, err;
 291 
 292         ASSERT(ds == NULL || MUTEX_HELD(&ds->ds_opening_lock));
 293 
 294         os = kmem_zalloc(sizeof (objset_t), KM_SLEEP);
 295         os->os_dsl_dataset = ds;
 296         os->os_spa = spa;
 297         os->os_rootbp = bp;
 298         if (!BP_IS_HOLE(os->os_rootbp)) {
 299                 arc_flags_t aflags = ARC_FLAG_WAIT;
 300                 zbookmark_phys_t zb;
 301                 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
 302                     ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
 303 
 304                 if (DMU_OS_IS_L2CACHEABLE(os))
 305                         aflags |= ARC_FLAG_L2CACHE;
 306                 if (DMU_OS_IS_L2COMPRESSIBLE(os))
 307                         aflags |= ARC_FLAG_L2COMPRESS;
 308 
 309                 dprintf_bp(os->os_rootbp, "reading %s", "");
 310                 err = arc_read(NULL, spa, os->os_rootbp,
 311                     arc_getbuf_func, &os->os_phys_buf,
 312                     ZIO_PRIORITY_SYNC_READ, ZIO_FLAG_CANFAIL, &aflags, &zb);
 313                 if (err != 0) {
 314                         kmem_free(os, sizeof (objset_t));
 315                         /* convert checksum errors into IO errors */
 316                         if (err == ECKSUM)
 317                                 err = SET_ERROR(EIO);
 318                         return (err);
 319                 }
 320 
 321                 /* Increase the blocksize if we are permitted. */
 322                 if (spa_version(spa) >= SPA_VERSION_USERSPACE &&
 323                     arc_buf_size(os->os_phys_buf) < sizeof (objset_phys_t)) {
 324                         arc_buf_t *buf = arc_buf_alloc(spa,
 325                             sizeof (objset_phys_t), &os->os_phys_buf,
 326                             ARC_BUFC_METADATA);
 327                         bzero(buf->b_data, sizeof (objset_phys_t));
 328                         bcopy(os->os_phys_buf->b_data, buf->b_data,
 329                             arc_buf_size(os->os_phys_buf));
 330                         (void) arc_buf_remove_ref(os->os_phys_buf,
 331                             &os->os_phys_buf);
 332                         os->os_phys_buf = buf;
 333                 }
 334 
 335                 os->os_phys = os->os_phys_buf->b_data;
 336                 os->os_flags = os->os_phys->os_flags;
 337         } else {
 338                 int size = spa_version(spa) >= SPA_VERSION_USERSPACE ?
 339                     sizeof (objset_phys_t) : OBJSET_OLD_PHYS_SIZE;
 340                 os->os_phys_buf = arc_buf_alloc(spa, size,
 341                     &os->os_phys_buf, ARC_BUFC_METADATA);
 342                 os->os_phys = os->os_phys_buf->b_data;
 343                 bzero(os->os_phys, size);
 344         }
 345 
 346         /*
 347          * Note: the changed_cb will be called once before the register
 348          * func returns, thus changing the checksum/compression from the
 349          * default (fletcher2/off).  Snapshots don't need to know about
 350          * checksum/compression/copies.
 351          */
 352         if (ds != NULL) {
 353                 err = dsl_prop_register(ds,
 354                     zfs_prop_to_name(ZFS_PROP_PRIMARYCACHE),
 355                     primary_cache_changed_cb, os);
 356                 if (err == 0) {
 357                         err = dsl_prop_register(ds,
 358                             zfs_prop_to_name(ZFS_PROP_SECONDARYCACHE),
 359                             secondary_cache_changed_cb, os);
 360                 }
 361                 if (!ds->ds_is_snapshot) {
 362                         if (err == 0) {
 363                                 err = dsl_prop_register(ds,
 364                                     zfs_prop_to_name(ZFS_PROP_CHECKSUM),
 365                                     checksum_changed_cb, os);
 366                         }
 367                         if (err == 0) {
 368                                 err = dsl_prop_register(ds,
 369                                     zfs_prop_to_name(ZFS_PROP_COMPRESSION),
 370                                     compression_changed_cb, os);
 371                         }
 372                         if (err == 0) {
 373                                 err = dsl_prop_register(ds,
 374                                     zfs_prop_to_name(ZFS_PROP_COPIES),
 375                                     copies_changed_cb, os);
 376                         }
 377                         if (err == 0) {
 378                                 err = dsl_prop_register(ds,
 379                                     zfs_prop_to_name(ZFS_PROP_DEDUP),
 380                                     dedup_changed_cb, os);
 381                         }
 382                         if (err == 0) {
 383                                 err = dsl_prop_register(ds,
 384                                     zfs_prop_to_name(ZFS_PROP_LOGBIAS),
 385                                     logbias_changed_cb, os);
 386                         }
 387                         if (err == 0) {
 388                                 err = dsl_prop_register(ds,
 389                                     zfs_prop_to_name(ZFS_PROP_SYNC),
 390                                     sync_changed_cb, os);
 391                         }
 392                         if (err == 0) {
 393                                 err = dsl_prop_register(ds,
 394                                     zfs_prop_to_name(
 395                                     ZFS_PROP_REDUNDANT_METADATA),
 396                                     redundant_metadata_changed_cb, os);
 397                         }
 398                         if (err == 0) {
 399                                 err = dsl_prop_register(ds,
 400                                     zfs_prop_to_name(ZFS_PROP_RECORDSIZE),
 401                                     recordsize_changed_cb, os);
 402                         }
 403                 }
 404                 if (err != 0) {
 405                         VERIFY(arc_buf_remove_ref(os->os_phys_buf,
 406                             &os->os_phys_buf));
 407                         kmem_free(os, sizeof (objset_t));
 408                         return (err);
 409                 }
 410         } else {
 411                 /* It's the meta-objset. */
 412                 os->os_checksum = ZIO_CHECKSUM_FLETCHER_4;
 413                 os->os_compress = ZIO_COMPRESS_ON;
 414                 os->os_copies = spa_max_replication(spa);
 415                 os->os_dedup_checksum = ZIO_CHECKSUM_OFF;
 416                 os->os_dedup_verify = B_FALSE;
 417                 os->os_logbias = ZFS_LOGBIAS_LATENCY;
 418                 os->os_sync = ZFS_SYNC_STANDARD;
 419                 os->os_primary_cache = ZFS_CACHE_ALL;
 420                 os->os_secondary_cache = ZFS_CACHE_ALL;
 421         }
 422 
 423         if (ds == NULL || !ds->ds_is_snapshot)
 424                 os->os_zil_header = os->os_phys->os_zil_header;
 425         os->os_zil = zil_alloc(os, &os->os_zil_header);
 426 
 427         for (i = 0; i < TXG_SIZE; i++) {
 428                 list_create(&os->os_dirty_dnodes[i], sizeof (dnode_t),
 429                     offsetof(dnode_t, dn_dirty_link[i]));
 430                 list_create(&os->os_free_dnodes[i], sizeof (dnode_t),
 431                     offsetof(dnode_t, dn_dirty_link[i]));
 432         }
 433         list_create(&os->os_dnodes, sizeof (dnode_t),
 434             offsetof(dnode_t, dn_link));
 435         list_create(&os->os_downgraded_dbufs, sizeof (dmu_buf_impl_t),
 436             offsetof(dmu_buf_impl_t, db_link));
 437 
 438         mutex_init(&os->os_lock, NULL, MUTEX_DEFAULT, NULL);
 439         mutex_init(&os->os_obj_lock, NULL, MUTEX_DEFAULT, NULL);
 440         mutex_init(&os->os_user_ptr_lock, NULL, MUTEX_DEFAULT, NULL);
 441 
 442         dnode_special_open(os, &os->os_phys->os_meta_dnode,
 443             DMU_META_DNODE_OBJECT, &os->os_meta_dnode);
 444         if (arc_buf_size(os->os_phys_buf) >= sizeof (objset_phys_t)) {
 445                 dnode_special_open(os, &os->os_phys->os_userused_dnode,
 446                     DMU_USERUSED_OBJECT, &os->os_userused_dnode);
 447                 dnode_special_open(os, &os->os_phys->os_groupused_dnode,
 448                     DMU_GROUPUSED_OBJECT, &os->os_groupused_dnode);
 449         }
 450 
 451         *osp = os;
 452         return (0);
 453 }
 454 
 455 int
 456 dmu_objset_from_ds(dsl_dataset_t *ds, objset_t **osp)
 457 {
 458         int err = 0;
 459 
 460         mutex_enter(&ds->ds_opening_lock);
 461         if (ds->ds_objset == NULL) {
 462                 objset_t *os;
 463                 err = dmu_objset_open_impl(dsl_dataset_get_spa(ds),
 464                     ds, dsl_dataset_get_blkptr(ds), &os);
 465 
 466                 if (err == 0) {
 467                         mutex_enter(&ds->ds_lock);
 468                         ASSERT(ds->ds_objset == NULL);
 469                         ds->ds_objset = os;
 470                         mutex_exit(&ds->ds_lock);
 471                 }
 472         }
 473         *osp = ds->ds_objset;
 474         mutex_exit(&ds->ds_opening_lock);
 475         return (err);
 476 }
 477 
 478 /*
 479  * Holds the pool while the objset is held.  Therefore only one objset
 480  * can be held at a time.
 481  */
 482 int
 483 dmu_objset_hold(const char *name, void *tag, objset_t **osp)
 484 {
 485         dsl_pool_t *dp;
 486         dsl_dataset_t *ds;
 487         int err;
 488 
 489         err = dsl_pool_hold(name, tag, &dp);
 490         if (err != 0)
 491                 return (err);
 492         err = dsl_dataset_hold(dp, name, tag, &ds);
 493         if (err != 0) {
 494                 dsl_pool_rele(dp, tag);
 495                 return (err);
 496         }
 497 
 498         err = dmu_objset_from_ds(ds, osp);
 499         if (err != 0) {
 500                 dsl_dataset_rele(ds, tag);
 501                 dsl_pool_rele(dp, tag);
 502         }
 503 
 504         return (err);
 505 }
 506 
 507 /*
 508  * dsl_pool must not be held when this is called.
 509  * Upon successful return, there will be a longhold on the dataset,
 510  * and the dsl_pool will not be held.
 511  */
 512 int
 513 dmu_objset_own(const char *name, dmu_objset_type_t type,
 514     boolean_t readonly, void *tag, objset_t **osp)
 515 {
 516         dsl_pool_t *dp;
 517         dsl_dataset_t *ds;
 518         int err;
 519 
 520         err = dsl_pool_hold(name, FTAG, &dp);
 521         if (err != 0)
 522                 return (err);
 523         err = dsl_dataset_own(dp, name, tag, &ds);
 524         if (err != 0) {
 525                 dsl_pool_rele(dp, FTAG);
 526                 return (err);
 527         }
 528 
 529         err = dmu_objset_from_ds(ds, osp);
 530         dsl_pool_rele(dp, FTAG);
 531         if (err != 0) {
 532                 dsl_dataset_disown(ds, tag);
 533         } else if (type != DMU_OST_ANY && type != (*osp)->os_phys->os_type) {
 534                 dsl_dataset_disown(ds, tag);
 535                 return (SET_ERROR(EINVAL));
 536         } else if (!readonly && ds->ds_is_snapshot) {
 537                 dsl_dataset_disown(ds, tag);
 538                 return (SET_ERROR(EROFS));
 539         }
 540         return (err);
 541 }
 542 
 543 void
 544 dmu_objset_rele(objset_t *os, void *tag)
 545 {
 546         dsl_pool_t *dp = dmu_objset_pool(os);
 547         dsl_dataset_rele(os->os_dsl_dataset, tag);
 548         dsl_pool_rele(dp, tag);
 549 }
 550 
 551 /*
 552  * When we are called, os MUST refer to an objset associated with a dataset
 553  * that is owned by 'tag'; that is, is held and long held by 'tag' and ds_owner
 554  * == tag.  We will then release and reacquire ownership of the dataset while
 555  * holding the pool config_rwlock to avoid intervening namespace or ownership
 556  * changes may occur.
 557  *
 558  * This exists solely to accommodate zfs_ioc_userspace_upgrade()'s desire to
 559  * release the hold on its dataset and acquire a new one on the dataset of the
 560  * same name so that it can be partially torn down and reconstructed.
 561  */
 562 void
 563 dmu_objset_refresh_ownership(objset_t *os, void *tag)
 564 {
 565         dsl_pool_t *dp;
 566         dsl_dataset_t *ds, *newds;
 567         char name[MAXNAMELEN];
 568 
 569         ds = os->os_dsl_dataset;
 570         VERIFY3P(ds, !=, NULL);
 571         VERIFY3P(ds->ds_owner, ==, tag);
 572         VERIFY(dsl_dataset_long_held(ds));
 573 
 574         dsl_dataset_name(ds, name);
 575         dp = dmu_objset_pool(os);
 576         dsl_pool_config_enter(dp, FTAG);
 577         dmu_objset_disown(os, tag);
 578         VERIFY0(dsl_dataset_own(dp, name, tag, &newds));
 579         VERIFY3P(newds, ==, os->os_dsl_dataset);
 580         dsl_pool_config_exit(dp, FTAG);
 581 }
 582 
 583 void
 584 dmu_objset_disown(objset_t *os, void *tag)
 585 {
 586         dsl_dataset_disown(os->os_dsl_dataset, tag);
 587 }
 588 
 589 void
 590 dmu_objset_evict_dbufs(objset_t *os)
 591 {
 592         dnode_t dn_marker;
 593         dnode_t *dn;
 594 
 595         mutex_enter(&os->os_lock);
 596         dn = list_head(&os->os_dnodes);
 597         while (dn != NULL) {
 598                 /*
 599                  * Skip dnodes without holds.  We have to do this dance
 600                  * because dnode_add_ref() only works if there is already a
 601                  * hold.  If the dnode has no holds, then it has no dbufs.
 602                  */
 603                 if (dnode_add_ref(dn, FTAG)) {
 604                         list_insert_after(&os->os_dnodes, dn, &dn_marker);
 605                         mutex_exit(&os->os_lock);
 606 
 607                         dnode_evict_dbufs(dn);
 608                         dnode_rele(dn, FTAG);
 609 
 610                         mutex_enter(&os->os_lock);
 611                         dn = list_next(&os->os_dnodes, &dn_marker);
 612                         list_remove(&os->os_dnodes, &dn_marker);
 613                 } else {
 614                         dn = list_next(&os->os_dnodes, dn);
 615                 }
 616         }
 617         mutex_exit(&os->os_lock);
 618 
 619         if (DMU_USERUSED_DNODE(os) != NULL) {
 620                 dnode_evict_dbufs(DMU_GROUPUSED_DNODE(os));
 621                 dnode_evict_dbufs(DMU_USERUSED_DNODE(os));
 622         }
 623         dnode_evict_dbufs(DMU_META_DNODE(os));
 624 }
 625 
 626 /*
 627  * Objset eviction processing is split into into two pieces.
 628  * The first marks the objset as evicting, evicts any dbufs that
 629  * have a refcount of zero, and then queues up the objset for the
 630  * second phase of eviction.  Once os->os_dnodes has been cleared by
 631  * dnode_buf_pageout()->dnode_destroy(), the second phase is executed.
 632  * The second phase closes the special dnodes, dequeues the objset from
 633  * the list of those undergoing eviction, and finally frees the objset.
 634  *
 635  * NOTE: Due to asynchronous eviction processing (invocation of
 636  *       dnode_buf_pageout()), it is possible for the meta dnode for the
 637  *       objset to have no holds even though os->os_dnodes is not empty.
 638  */
 639 void
 640 dmu_objset_evict(objset_t *os)
 641 {
 642         dsl_dataset_t *ds = os->os_dsl_dataset;
 643 
 644         for (int t = 0; t < TXG_SIZE; t++)
 645                 ASSERT(!dmu_objset_is_dirty(os, t));
 646 
 647         if (ds) {
 648                 if (!ds->ds_is_snapshot) {
 649                         VERIFY0(dsl_prop_unregister(ds,
 650                             zfs_prop_to_name(ZFS_PROP_CHECKSUM),
 651                             checksum_changed_cb, os));
 652                         VERIFY0(dsl_prop_unregister(ds,
 653                             zfs_prop_to_name(ZFS_PROP_COMPRESSION),
 654                             compression_changed_cb, os));
 655                         VERIFY0(dsl_prop_unregister(ds,
 656                             zfs_prop_to_name(ZFS_PROP_COPIES),
 657                             copies_changed_cb, os));
 658                         VERIFY0(dsl_prop_unregister(ds,
 659                             zfs_prop_to_name(ZFS_PROP_DEDUP),
 660                             dedup_changed_cb, os));
 661                         VERIFY0(dsl_prop_unregister(ds,
 662                             zfs_prop_to_name(ZFS_PROP_LOGBIAS),
 663                             logbias_changed_cb, os));
 664                         VERIFY0(dsl_prop_unregister(ds,
 665                             zfs_prop_to_name(ZFS_PROP_SYNC),
 666                             sync_changed_cb, os));
 667                         VERIFY0(dsl_prop_unregister(ds,
 668                             zfs_prop_to_name(ZFS_PROP_REDUNDANT_METADATA),
 669                             redundant_metadata_changed_cb, os));
 670                         VERIFY0(dsl_prop_unregister(ds,
 671                             zfs_prop_to_name(ZFS_PROP_RECORDSIZE),
 672                             recordsize_changed_cb, os));
 673                 }
 674                 VERIFY0(dsl_prop_unregister(ds,
 675                     zfs_prop_to_name(ZFS_PROP_PRIMARYCACHE),
 676                     primary_cache_changed_cb, os));
 677                 VERIFY0(dsl_prop_unregister(ds,
 678                     zfs_prop_to_name(ZFS_PROP_SECONDARYCACHE),
 679                     secondary_cache_changed_cb, os));
 680         }
 681 
 682         if (os->os_sa)
 683                 sa_tear_down(os);
 684 
 685         os->os_evicting = B_TRUE;
 686         dmu_objset_evict_dbufs(os);
 687 
 688         mutex_enter(&os->os_lock);
 689         spa_evicting_os_register(os->os_spa, os);
 690         if (list_is_empty(&os->os_dnodes)) {
 691                 mutex_exit(&os->os_lock);
 692                 dmu_objset_evict_done(os);
 693         } else {
 694                 mutex_exit(&os->os_lock);
 695         }
 696 }
 697 
 698 void
 699 dmu_objset_evict_done(objset_t *os)
 700 {
 701         ASSERT3P(list_head(&os->os_dnodes), ==, NULL);
 702 
 703         dnode_special_close(&os->os_meta_dnode);
 704         if (DMU_USERUSED_DNODE(os)) {
 705                 dnode_special_close(&os->os_userused_dnode);
 706                 dnode_special_close(&os->os_groupused_dnode);
 707         }
 708         zil_free(os->os_zil);
 709 
 710         VERIFY(arc_buf_remove_ref(os->os_phys_buf, &os->os_phys_buf));
 711 
 712         /*
 713          * This is a barrier to prevent the objset from going away in
 714          * dnode_move() until we can safely ensure that the objset is still in
 715          * use. We consider the objset valid before the barrier and invalid
 716          * after the barrier.
 717          */
 718         rw_enter(&os_lock, RW_READER);
 719         rw_exit(&os_lock);
 720 
 721         mutex_destroy(&os->os_lock);
 722         mutex_destroy(&os->os_obj_lock);
 723         mutex_destroy(&os->os_user_ptr_lock);
 724         spa_evicting_os_deregister(os->os_spa, os);
 725         kmem_free(os, sizeof (objset_t));
 726 }
 727 
 728 timestruc_t
 729 dmu_objset_snap_cmtime(objset_t *os)
 730 {
 731         return (dsl_dir_snap_cmtime(os->os_dsl_dataset->ds_dir));
 732 }
 733 
 734 /* called from dsl for meta-objset */
 735 objset_t *
 736 dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 737     dmu_objset_type_t type, dmu_tx_t *tx)
 738 {
 739         objset_t *os;
 740         dnode_t *mdn;
 741 
 742         ASSERT(dmu_tx_is_syncing(tx));
 743 
 744         if (ds != NULL)
 745                 VERIFY0(dmu_objset_from_ds(ds, &os));
 746         else
 747                 VERIFY0(dmu_objset_open_impl(spa, NULL, bp, &os));
 748 
 749         mdn = DMU_META_DNODE(os);
 750 
 751         dnode_allocate(mdn, DMU_OT_DNODE, 1 << DNODE_BLOCK_SHIFT,
 752             DN_MAX_INDBLKSHIFT, DMU_OT_NONE, 0, tx);
 753 
 754         /*
 755          * We don't want to have to increase the meta-dnode's nlevels
 756          * later, because then we could do it in quescing context while
 757          * we are also accessing it in open context.
 758          *
 759          * This precaution is not necessary for the MOS (ds == NULL),
 760          * because the MOS is only updated in syncing context.
 761          * This is most fortunate: the MOS is the only objset that
 762          * needs to be synced multiple times as spa_sync() iterates
 763          * to convergence, so minimizing its dn_nlevels matters.
 764          */
 765         if (ds != NULL) {
 766                 int levels = 1;
 767 
 768                 /*
 769                  * Determine the number of levels necessary for the meta-dnode
 770                  * to contain DN_MAX_OBJECT dnodes.
 771                  */
 772                 while ((uint64_t)mdn->dn_nblkptr << (mdn->dn_datablkshift +
 773                     (levels - 1) * (mdn->dn_indblkshift - SPA_BLKPTRSHIFT)) <
 774                     DN_MAX_OBJECT * sizeof (dnode_phys_t))
 775                         levels++;
 776 
 777                 mdn->dn_next_nlevels[tx->tx_txg & TXG_MASK] =
 778                     mdn->dn_nlevels = levels;
 779         }
 780 
 781         ASSERT(type != DMU_OST_NONE);
 782         ASSERT(type != DMU_OST_ANY);
 783         ASSERT(type < DMU_OST_NUMTYPES);
 784         os->os_phys->os_type = type;
 785         if (dmu_objset_userused_enabled(os)) {
 786                 os->os_phys->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
 787                 os->os_flags = os->os_phys->os_flags;
 788         }
 789 
 790         dsl_dataset_dirty(ds, tx);
 791 
 792         return (os);
 793 }
 794 
 795 typedef struct dmu_objset_create_arg {
 796         const char *doca_name;
 797         cred_t *doca_cred;
 798         void (*doca_userfunc)(objset_t *os, void *arg,
 799             cred_t *cr, dmu_tx_t *tx);
 800         void *doca_userarg;
 801         dmu_objset_type_t doca_type;
 802         uint64_t doca_flags;
 803 } dmu_objset_create_arg_t;
 804 
 805 /*ARGSUSED*/
 806 static int
 807 dmu_objset_create_check(void *arg, dmu_tx_t *tx)
 808 {
 809         dmu_objset_create_arg_t *doca = arg;
 810         dsl_pool_t *dp = dmu_tx_pool(tx);
 811         dsl_dir_t *pdd;
 812         const char *tail;
 813         int error;
 814 
 815         if (strchr(doca->doca_name, '@') != NULL)
 816                 return (SET_ERROR(EINVAL));
 817 
 818         error = dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail);
 819         if (error != 0)
 820                 return (error);
 821         if (tail == NULL) {
 822                 dsl_dir_rele(pdd, FTAG);
 823                 return (SET_ERROR(EEXIST));
 824         }
 825         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 826             doca->doca_cred);
 827         dsl_dir_rele(pdd, FTAG);
 828 
 829         return (error);
 830 }
 831 
 832 static void
 833 dmu_objset_create_sync(void *arg, dmu_tx_t *tx)
 834 {
 835         dmu_objset_create_arg_t *doca = arg;
 836         dsl_pool_t *dp = dmu_tx_pool(tx);
 837         dsl_dir_t *pdd;
 838         const char *tail;
 839         dsl_dataset_t *ds;
 840         uint64_t obj;
 841         blkptr_t *bp;
 842         objset_t *os;
 843 
 844         VERIFY0(dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail));
 845 
 846         obj = dsl_dataset_create_sync(pdd, tail, NULL, doca->doca_flags,
 847             doca->doca_cred, tx);
 848 
 849         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 850         bp = dsl_dataset_get_blkptr(ds);
 851         os = dmu_objset_create_impl(pdd->dd_pool->dp_spa,
 852             ds, bp, doca->doca_type, tx);
 853 
 854         if (doca->doca_userfunc != NULL) {
 855                 doca->doca_userfunc(os, doca->doca_userarg,
 856                     doca->doca_cred, tx);
 857         }
 858 
 859         spa_history_log_internal_ds(ds, "create", tx, "");
 860         dsl_dataset_rele(ds, FTAG);
 861         dsl_dir_rele(pdd, FTAG);
 862 }
 863 
 864 int
 865 dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
 866     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg)
 867 {
 868         dmu_objset_create_arg_t doca;
 869 
 870         doca.doca_name = name;
 871         doca.doca_cred = CRED();
 872         doca.doca_flags = flags;
 873         doca.doca_userfunc = func;
 874         doca.doca_userarg = arg;
 875         doca.doca_type = type;
 876 
 877         return (dsl_sync_task(name,
 878             dmu_objset_create_check, dmu_objset_create_sync, &doca,
 879             5, ZFS_SPACE_CHECK_NORMAL));
 880 }
 881 
 882 typedef struct dmu_objset_clone_arg {
 883         const char *doca_clone;
 884         const char *doca_origin;
 885         cred_t *doca_cred;
 886 } dmu_objset_clone_arg_t;
 887 
 888 /*ARGSUSED*/
 889 static int
 890 dmu_objset_clone_check(void *arg, dmu_tx_t *tx)
 891 {
 892         dmu_objset_clone_arg_t *doca = arg;
 893         dsl_dir_t *pdd;
 894         const char *tail;
 895         int error;
 896         dsl_dataset_t *origin;
 897         dsl_pool_t *dp = dmu_tx_pool(tx);
 898 
 899         if (strchr(doca->doca_clone, '@') != NULL)
 900                 return (SET_ERROR(EINVAL));
 901 
 902         error = dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail);
 903         if (error != 0)
 904                 return (error);
 905         if (tail == NULL) {
 906                 dsl_dir_rele(pdd, FTAG);
 907                 return (SET_ERROR(EEXIST));
 908         }
 909 
 910         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 911             doca->doca_cred);
 912         if (error != 0) {
 913                 dsl_dir_rele(pdd, FTAG);
 914                 return (SET_ERROR(EDQUOT));
 915         }
 916         dsl_dir_rele(pdd, FTAG);
 917 
 918         error = dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin);
 919         if (error != 0)
 920                 return (error);
 921 
 922         /* You can only clone snapshots, not the head datasets. */
 923         if (!origin->ds_is_snapshot) {
 924                 dsl_dataset_rele(origin, FTAG);
 925                 return (SET_ERROR(EINVAL));
 926         }
 927         dsl_dataset_rele(origin, FTAG);
 928 
 929         return (0);
 930 }
 931 
 932 static void
 933 dmu_objset_clone_sync(void *arg, dmu_tx_t *tx)
 934 {
 935         dmu_objset_clone_arg_t *doca = arg;
 936         dsl_pool_t *dp = dmu_tx_pool(tx);
 937         dsl_dir_t *pdd;
 938         const char *tail;
 939         dsl_dataset_t *origin, *ds;
 940         uint64_t obj;
 941         char namebuf[MAXNAMELEN];
 942 
 943         VERIFY0(dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail));
 944         VERIFY0(dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin));
 945 
 946         obj = dsl_dataset_create_sync(pdd, tail, origin, 0,
 947             doca->doca_cred, tx);
 948 
 949         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 950         dsl_dataset_name(origin, namebuf);
 951         spa_history_log_internal_ds(ds, "clone", tx,
 952             "origin=%s (%llu)", namebuf, origin->ds_object);
 953         dsl_dataset_rele(ds, FTAG);
 954         dsl_dataset_rele(origin, FTAG);
 955         dsl_dir_rele(pdd, FTAG);
 956 }
 957 
 958 int
 959 dmu_objset_clone(const char *clone, const char *origin)
 960 {
 961         dmu_objset_clone_arg_t doca;
 962 
 963         doca.doca_clone = clone;
 964         doca.doca_origin = origin;
 965         doca.doca_cred = CRED();
 966 
 967         return (dsl_sync_task(clone,
 968             dmu_objset_clone_check, dmu_objset_clone_sync, &doca,
 969             5, ZFS_SPACE_CHECK_NORMAL));
 970 }
 971 
 972 int
 973 dmu_objset_snapshot_one(const char *fsname, const char *snapname)
 974 {
 975         int err;
 976         char *longsnap = kmem_asprintf("%s@%s", fsname, snapname);
 977         nvlist_t *snaps = fnvlist_alloc();
 978 
 979         fnvlist_add_boolean(snaps, longsnap);
 980         strfree(longsnap);
 981         err = dsl_dataset_snapshot(snaps, NULL, NULL);
 982         fnvlist_free(snaps);
 983         return (err);
 984 }
 985 
 986 static void
 987 dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
 988 {
 989         dnode_t *dn;
 990 
 991         while (dn = list_head(list)) {
 992                 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
 993                 ASSERT(dn->dn_dbuf->db_data_pending);
 994                 /*
 995                  * Initialize dn_zio outside dnode_sync() because the
 996                  * meta-dnode needs to set it ouside dnode_sync().
 997                  */
 998                 dn->dn_zio = dn->dn_dbuf->db_data_pending->dr_zio;
 999                 ASSERT(dn->dn_zio);
1000 
1001                 ASSERT3U(dn->dn_nlevels, <=, DN_MAX_LEVELS);
1002                 list_remove(list, dn);
1003 
1004                 if (newlist) {
1005                         (void) dnode_add_ref(dn, newlist);
1006                         list_insert_tail(newlist, dn);
1007                 }
1008 
1009                 dnode_sync(dn, tx);
1010         }
1011 }
1012 
1013 /* ARGSUSED */
1014 static void
1015 dmu_objset_write_ready(zio_t *zio, arc_buf_t *abuf, void *arg)
1016 {
1017         blkptr_t *bp = zio->io_bp;
1018         objset_t *os = arg;
1019         dnode_phys_t *dnp = &os->os_phys->os_meta_dnode;
1020 
1021         ASSERT(!BP_IS_EMBEDDED(bp));
1022         ASSERT3P(bp, ==, os->os_rootbp);
1023         ASSERT3U(BP_GET_TYPE(bp), ==, DMU_OT_OBJSET);
1024         ASSERT0(BP_GET_LEVEL(bp));
1025 
1026         /*
1027          * Update rootbp fill count: it should be the number of objects
1028          * allocated in the object set (not counting the "special"
1029          * objects that are stored in the objset_phys_t -- the meta
1030          * dnode and user/group accounting objects).
1031          */
1032         bp->blk_fill = 0;
1033         for (int i = 0; i < dnp->dn_nblkptr; i++)
1034                 bp->blk_fill += BP_GET_FILL(&dnp->dn_blkptr[i]);
1035 }
1036 
1037 /* ARGSUSED */
1038 static void
1039 dmu_objset_write_done(zio_t *zio, arc_buf_t *abuf, void *arg)
1040 {
1041         blkptr_t *bp = zio->io_bp;
1042         blkptr_t *bp_orig = &zio->io_bp_orig;
1043         objset_t *os = arg;
1044 
1045         if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
1046                 ASSERT(BP_EQUAL(bp, bp_orig));
1047         } else {
1048                 dsl_dataset_t *ds = os->os_dsl_dataset;
1049                 dmu_tx_t *tx = os->os_synctx;
1050 
1051                 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
1052                 dsl_dataset_block_born(ds, bp, tx);
1053         }
1054 }
1055 
1056 /* called from dsl */
1057 void
1058 dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
1059 {
1060         int txgoff;
1061         zbookmark_phys_t zb;
1062         zio_prop_t zp;
1063         zio_t *zio;
1064         list_t *list;
1065         list_t *newlist = NULL;
1066         dbuf_dirty_record_t *dr;
1067 
1068         dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
1069 
1070         ASSERT(dmu_tx_is_syncing(tx));
1071         /* XXX the write_done callback should really give us the tx... */
1072         os->os_synctx = tx;
1073 
1074         if (os->os_dsl_dataset == NULL) {
1075                 /*
1076                  * This is the MOS.  If we have upgraded,
1077                  * spa_max_replication() could change, so reset
1078                  * os_copies here.
1079                  */
1080                 os->os_copies = spa_max_replication(os->os_spa);
1081         }
1082 
1083         /*
1084          * Create the root block IO
1085          */
1086         SET_BOOKMARK(&zb, os->os_dsl_dataset ?
1087             os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
1088             ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
1089         arc_release(os->os_phys_buf, &os->os_phys_buf);
1090 
1091         dmu_write_policy(os, NULL, 0, 0, &zp);
1092 
1093         zio = arc_write(pio, os->os_spa, tx->tx_txg,
1094             os->os_rootbp, os->os_phys_buf, DMU_OS_IS_L2CACHEABLE(os),
1095             DMU_OS_IS_L2COMPRESSIBLE(os), &zp, dmu_objset_write_ready,
1096             NULL, dmu_objset_write_done, os, ZIO_PRIORITY_ASYNC_WRITE,
1097             ZIO_FLAG_MUSTSUCCEED, &zb);
1098 
1099         /*
1100          * Sync special dnodes - the parent IO for the sync is the root block
1101          */
1102         DMU_META_DNODE(os)->dn_zio = zio;
1103         dnode_sync(DMU_META_DNODE(os), tx);
1104 
1105         os->os_phys->os_flags = os->os_flags;
1106 
1107         if (DMU_USERUSED_DNODE(os) &&
1108             DMU_USERUSED_DNODE(os)->dn_type != DMU_OT_NONE) {
1109                 DMU_USERUSED_DNODE(os)->dn_zio = zio;
1110                 dnode_sync(DMU_USERUSED_DNODE(os), tx);
1111                 DMU_GROUPUSED_DNODE(os)->dn_zio = zio;
1112                 dnode_sync(DMU_GROUPUSED_DNODE(os), tx);
1113         }
1114 
1115         txgoff = tx->tx_txg & TXG_MASK;
1116 
1117         if (dmu_objset_userused_enabled(os)) {
1118                 newlist = &os->os_synced_dnodes;
1119                 /*
1120                  * We must create the list here because it uses the
1121                  * dn_dirty_link[] of this txg.
1122                  */
1123                 list_create(newlist, sizeof (dnode_t),
1124                     offsetof(dnode_t, dn_dirty_link[txgoff]));
1125         }
1126 
1127         dmu_objset_sync_dnodes(&os->os_free_dnodes[txgoff], newlist, tx);
1128         dmu_objset_sync_dnodes(&os->os_dirty_dnodes[txgoff], newlist, tx);
1129 
1130         list = &DMU_META_DNODE(os)->dn_dirty_records[txgoff];
1131         while (dr = list_head(list)) {
1132                 ASSERT0(dr->dr_dbuf->db_level);
1133                 list_remove(list, dr);
1134                 if (dr->dr_zio)
1135                         zio_nowait(dr->dr_zio);
1136         }
1137         /*
1138          * Free intent log blocks up to this tx.
1139          */
1140         zil_sync(os->os_zil, tx);
1141         os->os_phys->os_zil_header = os->os_zil_header;
1142         zio_nowait(zio);
1143 }
1144 
1145 boolean_t
1146 dmu_objset_is_dirty(objset_t *os, uint64_t txg)
1147 {
1148         return (!list_is_empty(&os->os_dirty_dnodes[txg & TXG_MASK]) ||
1149             !list_is_empty(&os->os_free_dnodes[txg & TXG_MASK]));
1150 }
1151 
1152 static objset_used_cb_t *used_cbs[DMU_OST_NUMTYPES];
1153 
1154 void
1155 dmu_objset_register_type(dmu_objset_type_t ost, objset_used_cb_t *cb)
1156 {
1157         used_cbs[ost] = cb;
1158 }
1159 
1160 boolean_t
1161 dmu_objset_userused_enabled(objset_t *os)
1162 {
1163         return (spa_version(os->os_spa) >= SPA_VERSION_USERSPACE &&
1164             used_cbs[os->os_phys->os_type] != NULL &&
1165             DMU_USERUSED_DNODE(os) != NULL);
1166 }
1167 
1168 static void
1169 do_userquota_update(objset_t *os, uint64_t used, uint64_t flags,
1170     uint64_t user, uint64_t group, boolean_t subtract, dmu_tx_t *tx)
1171 {
1172         if ((flags & DNODE_FLAG_USERUSED_ACCOUNTED)) {
1173                 int64_t delta = DNODE_SIZE + used;
1174                 if (subtract)
1175                         delta = -delta;
1176                 VERIFY3U(0, ==, zap_increment_int(os, DMU_USERUSED_OBJECT,
1177                     user, delta, tx));
1178                 VERIFY3U(0, ==, zap_increment_int(os, DMU_GROUPUSED_OBJECT,
1179                     group, delta, tx));
1180         }
1181 }
1182 
1183 void
1184 dmu_objset_do_userquota_updates(objset_t *os, dmu_tx_t *tx)
1185 {
1186         dnode_t *dn;
1187         list_t *list = &os->os_synced_dnodes;
1188 
1189         ASSERT(list_head(list) == NULL || dmu_objset_userused_enabled(os));
1190 
1191         while (dn = list_head(list)) {
1192                 int flags;
1193                 ASSERT(!DMU_OBJECT_IS_SPECIAL(dn->dn_object));
1194                 ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE ||
1195                     dn->dn_phys->dn_flags &
1196                     DNODE_FLAG_USERUSED_ACCOUNTED);
1197 
1198                 /* Allocate the user/groupused objects if necessary. */
1199                 if (DMU_USERUSED_DNODE(os)->dn_type == DMU_OT_NONE) {
1200                         VERIFY(0 == zap_create_claim(os,
1201                             DMU_USERUSED_OBJECT,
1202                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1203                         VERIFY(0 == zap_create_claim(os,
1204                             DMU_GROUPUSED_OBJECT,
1205                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1206                 }
1207 
1208                 /*
1209                  * We intentionally modify the zap object even if the
1210                  * net delta is zero.  Otherwise
1211                  * the block of the zap obj could be shared between
1212                  * datasets but need to be different between them after
1213                  * a bprewrite.
1214                  */
1215 
1216                 flags = dn->dn_id_flags;
1217                 ASSERT(flags);
1218                 if (flags & DN_ID_OLD_EXIST)  {
1219                         do_userquota_update(os, dn->dn_oldused, dn->dn_oldflags,
1220                             dn->dn_olduid, dn->dn_oldgid, B_TRUE, tx);
1221                 }
1222                 if (flags & DN_ID_NEW_EXIST) {
1223                         do_userquota_update(os, DN_USED_BYTES(dn->dn_phys),
1224                             dn->dn_phys->dn_flags,  dn->dn_newuid,
1225                             dn->dn_newgid, B_FALSE, tx);
1226                 }
1227 
1228                 mutex_enter(&dn->dn_mtx);
1229                 dn->dn_oldused = 0;
1230                 dn->dn_oldflags = 0;
1231                 if (dn->dn_id_flags & DN_ID_NEW_EXIST) {
1232                         dn->dn_olduid = dn->dn_newuid;
1233                         dn->dn_oldgid = dn->dn_newgid;
1234                         dn->dn_id_flags |= DN_ID_OLD_EXIST;
1235                         if (dn->dn_bonuslen == 0)
1236                                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1237                         else
1238                                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1239                 }
1240                 dn->dn_id_flags &= ~(DN_ID_NEW_EXIST);
1241                 mutex_exit(&dn->dn_mtx);
1242 
1243                 list_remove(list, dn);
1244                 dnode_rele(dn, list);
1245         }
1246 }
1247 
1248 /*
1249  * Returns a pointer to data to find uid/gid from
1250  *
1251  * If a dirty record for transaction group that is syncing can't
1252  * be found then NULL is returned.  In the NULL case it is assumed
1253  * the uid/gid aren't changing.
1254  */
1255 static void *
1256 dmu_objset_userquota_find_data(dmu_buf_impl_t *db, dmu_tx_t *tx)
1257 {
1258         dbuf_dirty_record_t *dr, **drp;
1259         void *data;
1260 
1261         if (db->db_dirtycnt == 0)
1262                 return (db->db.db_data);  /* Nothing is changing */
1263 
1264         for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1265                 if (dr->dr_txg == tx->tx_txg)
1266                         break;
1267 
1268         if (dr == NULL) {
1269                 data = NULL;
1270         } else {
1271                 dnode_t *dn;
1272 
1273                 DB_DNODE_ENTER(dr->dr_dbuf);
1274                 dn = DB_DNODE(dr->dr_dbuf);
1275 
1276                 if (dn->dn_bonuslen == 0 &&
1277                     dr->dr_dbuf->db_blkid == DMU_SPILL_BLKID)
1278                         data = dr->dt.dl.dr_data->b_data;
1279                 else
1280                         data = dr->dt.dl.dr_data;
1281 
1282                 DB_DNODE_EXIT(dr->dr_dbuf);
1283         }
1284 
1285         return (data);
1286 }
1287 
1288 void
1289 dmu_objset_userquota_get_ids(dnode_t *dn, boolean_t before, dmu_tx_t *tx)
1290 {
1291         objset_t *os = dn->dn_objset;
1292         void *data = NULL;
1293         dmu_buf_impl_t *db = NULL;
1294         uint64_t *user = NULL;
1295         uint64_t *group = NULL;
1296         int flags = dn->dn_id_flags;
1297         int error;
1298         boolean_t have_spill = B_FALSE;
1299 
1300         if (!dmu_objset_userused_enabled(dn->dn_objset))
1301                 return;
1302 
1303         if (before && (flags & (DN_ID_CHKED_BONUS|DN_ID_OLD_EXIST|
1304             DN_ID_CHKED_SPILL)))
1305                 return;
1306 
1307         if (before && dn->dn_bonuslen != 0)
1308                 data = DN_BONUS(dn->dn_phys);
1309         else if (!before && dn->dn_bonuslen != 0) {
1310                 if (dn->dn_bonus) {
1311                         db = dn->dn_bonus;
1312                         mutex_enter(&db->db_mtx);
1313                         data = dmu_objset_userquota_find_data(db, tx);
1314                 } else {
1315                         data = DN_BONUS(dn->dn_phys);
1316                 }
1317         } else if (dn->dn_bonuslen == 0 && dn->dn_bonustype == DMU_OT_SA) {
1318                         int rf = 0;
1319 
1320                         if (RW_WRITE_HELD(&dn->dn_struct_rwlock))
1321                                 rf |= DB_RF_HAVESTRUCT;
1322                         error = dmu_spill_hold_by_dnode(dn,
1323                             rf | DB_RF_MUST_SUCCEED,
1324                             FTAG, (dmu_buf_t **)&db);
1325                         ASSERT(error == 0);
1326                         mutex_enter(&db->db_mtx);
1327                         data = (before) ? db->db.db_data :
1328                             dmu_objset_userquota_find_data(db, tx);
1329                         have_spill = B_TRUE;
1330         } else {
1331                 mutex_enter(&dn->dn_mtx);
1332                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1333                 mutex_exit(&dn->dn_mtx);
1334                 return;
1335         }
1336 
1337         if (before) {
1338                 ASSERT(data);
1339                 user = &dn->dn_olduid;
1340                 group = &dn->dn_oldgid;
1341         } else if (data) {
1342                 user = &dn->dn_newuid;
1343                 group = &dn->dn_newgid;
1344         }
1345 
1346         /*
1347          * Must always call the callback in case the object
1348          * type has changed and that type isn't an object type to track
1349          */
1350         error = used_cbs[os->os_phys->os_type](dn->dn_bonustype, data,
1351             user, group);
1352 
1353         /*
1354          * Preserve existing uid/gid when the callback can't determine
1355          * what the new uid/gid are and the callback returned EEXIST.
1356          * The EEXIST error tells us to just use the existing uid/gid.
1357          * If we don't know what the old values are then just assign
1358          * them to 0, since that is a new file  being created.
1359          */
1360         if (!before && data == NULL && error == EEXIST) {
1361                 if (flags & DN_ID_OLD_EXIST) {
1362                         dn->dn_newuid = dn->dn_olduid;
1363                         dn->dn_newgid = dn->dn_oldgid;
1364                 } else {
1365                         dn->dn_newuid = 0;
1366                         dn->dn_newgid = 0;
1367                 }
1368                 error = 0;
1369         }
1370 
1371         if (db)
1372                 mutex_exit(&db->db_mtx);
1373 
1374         mutex_enter(&dn->dn_mtx);
1375         if (error == 0 && before)
1376                 dn->dn_id_flags |= DN_ID_OLD_EXIST;
1377         if (error == 0 && !before)
1378                 dn->dn_id_flags |= DN_ID_NEW_EXIST;
1379 
1380         if (have_spill) {
1381                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1382         } else {
1383                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1384         }
1385         mutex_exit(&dn->dn_mtx);
1386         if (have_spill)
1387                 dmu_buf_rele((dmu_buf_t *)db, FTAG);
1388 }
1389 
1390 boolean_t
1391 dmu_objset_userspace_present(objset_t *os)
1392 {
1393         return (os->os_phys->os_flags &
1394             OBJSET_FLAG_USERACCOUNTING_COMPLETE);
1395 }
1396 
1397 int
1398 dmu_objset_userspace_upgrade(objset_t *os)
1399 {
1400         uint64_t obj;
1401         int err = 0;
1402 
1403         if (dmu_objset_userspace_present(os))
1404                 return (0);
1405         if (!dmu_objset_userused_enabled(os))
1406                 return (SET_ERROR(ENOTSUP));
1407         if (dmu_objset_is_snapshot(os))
1408                 return (SET_ERROR(EINVAL));
1409 
1410         /*
1411          * We simply need to mark every object dirty, so that it will be
1412          * synced out and now accounted.  If this is called
1413          * concurrently, or if we already did some work before crashing,
1414          * that's fine, since we track each object's accounted state
1415          * independently.
1416          */
1417 
1418         for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, 0)) {
1419                 dmu_tx_t *tx;
1420                 dmu_buf_t *db;
1421                 int objerr;
1422 
1423                 if (issig(JUSTLOOKING) && issig(FORREAL))
1424                         return (SET_ERROR(EINTR));
1425 
1426                 objerr = dmu_bonus_hold(os, obj, FTAG, &db);
1427                 if (objerr != 0)
1428                         continue;
1429                 tx = dmu_tx_create(os);
1430                 dmu_tx_hold_bonus(tx, obj);
1431                 objerr = dmu_tx_assign(tx, TXG_WAIT);
1432                 if (objerr != 0) {
1433                         dmu_tx_abort(tx);
1434                         continue;
1435                 }
1436                 dmu_buf_will_dirty(db, tx);
1437                 dmu_buf_rele(db, FTAG);
1438                 dmu_tx_commit(tx);
1439         }
1440 
1441         os->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
1442         txg_wait_synced(dmu_objset_pool(os), 0);
1443         return (0);
1444 }
1445 
1446 void
1447 dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
1448     uint64_t *usedobjsp, uint64_t *availobjsp)
1449 {
1450         dsl_dataset_space(os->os_dsl_dataset, refdbytesp, availbytesp,
1451             usedobjsp, availobjsp);
1452 }
1453 
1454 uint64_t
1455 dmu_objset_fsid_guid(objset_t *os)
1456 {
1457         return (dsl_dataset_fsid_guid(os->os_dsl_dataset));
1458 }
1459 
1460 void
1461 dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat)
1462 {
1463         stat->dds_type = os->os_phys->os_type;
1464         if (os->os_dsl_dataset)
1465                 dsl_dataset_fast_stat(os->os_dsl_dataset, stat);
1466 }
1467 
1468 void
1469 dmu_objset_stats(objset_t *os, nvlist_t *nv)
1470 {
1471         ASSERT(os->os_dsl_dataset ||
1472             os->os_phys->os_type == DMU_OST_META);
1473 
1474         if (os->os_dsl_dataset != NULL)
1475                 dsl_dataset_stats(os->os_dsl_dataset, nv);
1476 
1477         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_TYPE,
1478             os->os_phys->os_type);
1479         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERACCOUNTING,
1480             dmu_objset_userspace_present(os));
1481 }
1482 
1483 int
1484 dmu_objset_is_snapshot(objset_t *os)
1485 {
1486         if (os->os_dsl_dataset != NULL)
1487                 return (os->os_dsl_dataset->ds_is_snapshot);
1488         else
1489                 return (B_FALSE);
1490 }
1491 
1492 int
1493 dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen,
1494     boolean_t *conflict)
1495 {
1496         dsl_dataset_t *ds = os->os_dsl_dataset;
1497         uint64_t ignored;
1498 
1499         if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
1500                 return (SET_ERROR(ENOENT));
1501 
1502         return (zap_lookup_norm(ds->ds_dir->dd_pool->dp_meta_objset,
1503             dsl_dataset_phys(ds)->ds_snapnames_zapobj, name, 8, 1, &ignored,
1504             MT_FIRST, real, maxlen, conflict));
1505 }
1506 
1507 int
1508 dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
1509     uint64_t *idp, uint64_t *offp, boolean_t *case_conflict)
1510 {
1511         dsl_dataset_t *ds = os->os_dsl_dataset;
1512         zap_cursor_t cursor;
1513         zap_attribute_t attr;
1514 
1515         ASSERT(dsl_pool_config_held(dmu_objset_pool(os)));
1516 
1517         if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
1518                 return (SET_ERROR(ENOENT));
1519 
1520         zap_cursor_init_serialized(&cursor,
1521             ds->ds_dir->dd_pool->dp_meta_objset,
1522             dsl_dataset_phys(ds)->ds_snapnames_zapobj, *offp);
1523 
1524         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1525                 zap_cursor_fini(&cursor);
1526                 return (SET_ERROR(ENOENT));
1527         }
1528 
1529         if (strlen(attr.za_name) + 1 > namelen) {
1530                 zap_cursor_fini(&cursor);
1531                 return (SET_ERROR(ENAMETOOLONG));
1532         }
1533 
1534         (void) strcpy(name, attr.za_name);
1535         if (idp)
1536                 *idp = attr.za_first_integer;
1537         if (case_conflict)
1538                 *case_conflict = attr.za_normalization_conflict;
1539         zap_cursor_advance(&cursor);
1540         *offp = zap_cursor_serialize(&cursor);
1541         zap_cursor_fini(&cursor);
1542 
1543         return (0);
1544 }
1545 
1546 int
1547 dmu_dir_list_next(objset_t *os, int namelen, char *name,
1548     uint64_t *idp, uint64_t *offp)
1549 {
1550         dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
1551         zap_cursor_t cursor;
1552         zap_attribute_t attr;
1553 
1554         /* there is no next dir on a snapshot! */
1555         if (os->os_dsl_dataset->ds_object !=
1556             dsl_dir_phys(dd)->dd_head_dataset_obj)
1557                 return (SET_ERROR(ENOENT));
1558 
1559         zap_cursor_init_serialized(&cursor,
1560             dd->dd_pool->dp_meta_objset,
1561             dsl_dir_phys(dd)->dd_child_dir_zapobj, *offp);
1562 
1563         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1564                 zap_cursor_fini(&cursor);
1565                 return (SET_ERROR(ENOENT));
1566         }
1567 
1568         if (strlen(attr.za_name) + 1 > namelen) {
1569                 zap_cursor_fini(&cursor);
1570                 return (SET_ERROR(ENAMETOOLONG));
1571         }
1572 
1573         (void) strcpy(name, attr.za_name);
1574         if (idp)
1575                 *idp = attr.za_first_integer;
1576         zap_cursor_advance(&cursor);
1577         *offp = zap_cursor_serialize(&cursor);
1578         zap_cursor_fini(&cursor);
1579 
1580         return (0);
1581 }
1582 
1583 /*
1584  * Find objsets under and including ddobj, call func(ds) on each.
1585  */
1586 int
1587 dmu_objset_find_dp(dsl_pool_t *dp, uint64_t ddobj,
1588     int func(dsl_pool_t *, dsl_dataset_t *, void *), void *arg, int flags)
1589 {
1590         dsl_dir_t *dd;
1591         dsl_dataset_t *ds;
1592         zap_cursor_t zc;
1593         zap_attribute_t *attr;
1594         uint64_t thisobj;
1595         int err;
1596 
1597         ASSERT(dsl_pool_config_held(dp));
1598 
1599         err = dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd);
1600         if (err != 0)
1601                 return (err);
1602 
1603         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1604         if (dd->dd_myname[0] == '$') {
1605                 dsl_dir_rele(dd, FTAG);
1606                 return (0);
1607         }
1608 
1609         thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
1610         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1611 
1612         /*
1613          * Iterate over all children.
1614          */
1615         if (flags & DS_FIND_CHILDREN) {
1616                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1617                     dsl_dir_phys(dd)->dd_child_dir_zapobj);
1618                     zap_cursor_retrieve(&zc, attr) == 0;
1619                     (void) zap_cursor_advance(&zc)) {
1620                         ASSERT3U(attr->za_integer_length, ==,
1621                             sizeof (uint64_t));
1622                         ASSERT3U(attr->za_num_integers, ==, 1);
1623 
1624                         err = dmu_objset_find_dp(dp, attr->za_first_integer,
1625                             func, arg, flags);
1626                         if (err != 0)
1627                                 break;
1628                 }
1629                 zap_cursor_fini(&zc);
1630 
1631                 if (err != 0) {
1632                         dsl_dir_rele(dd, FTAG);
1633                         kmem_free(attr, sizeof (zap_attribute_t));
1634                         return (err);
1635                 }
1636         }
1637 
1638         /*
1639          * Iterate over all snapshots.
1640          */
1641         if (flags & DS_FIND_SNAPSHOTS) {
1642                 dsl_dataset_t *ds;
1643                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1644 
1645                 if (err == 0) {
1646                         uint64_t snapobj;
1647 
1648                         snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
1649                         dsl_dataset_rele(ds, FTAG);
1650 
1651                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1652                             zap_cursor_retrieve(&zc, attr) == 0;
1653                             (void) zap_cursor_advance(&zc)) {
1654                                 ASSERT3U(attr->za_integer_length, ==,
1655                                     sizeof (uint64_t));
1656                                 ASSERT3U(attr->za_num_integers, ==, 1);
1657 
1658                                 err = dsl_dataset_hold_obj(dp,
1659                                     attr->za_first_integer, FTAG, &ds);
1660                                 if (err != 0)
1661                                         break;
1662                                 err = func(dp, ds, arg);
1663                                 dsl_dataset_rele(ds, FTAG);
1664                                 if (err != 0)
1665                                         break;
1666                         }
1667                         zap_cursor_fini(&zc);
1668                 }
1669         }
1670 
1671         dsl_dir_rele(dd, FTAG);
1672         kmem_free(attr, sizeof (zap_attribute_t));
1673 
1674         if (err != 0)
1675                 return (err);
1676 
1677         /*
1678          * Apply to self.
1679          */
1680         err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1681         if (err != 0)
1682                 return (err);
1683         err = func(dp, ds, arg);
1684         dsl_dataset_rele(ds, FTAG);
1685         return (err);
1686 }
1687 
1688 /*
1689  * Find all objsets under name, and for each, call 'func(child_name, arg)'.
1690  * The dp_config_rwlock must not be held when this is called, and it
1691  * will not be held when the callback is called.
1692  * Therefore this function should only be used when the pool is not changing
1693  * (e.g. in syncing context), or the callback can deal with the possible races.
1694  */
1695 static int
1696 dmu_objset_find_impl(spa_t *spa, const char *name,
1697     int func(const char *, void *), void *arg, int flags)
1698 {
1699         dsl_dir_t *dd;
1700         dsl_pool_t *dp = spa_get_dsl(spa);
1701         dsl_dataset_t *ds;
1702         zap_cursor_t zc;
1703         zap_attribute_t *attr;
1704         char *child;
1705         uint64_t thisobj;
1706         int err;
1707 
1708         dsl_pool_config_enter(dp, FTAG);
1709 
1710         err = dsl_dir_hold(dp, name, FTAG, &dd, NULL);
1711         if (err != 0) {
1712                 dsl_pool_config_exit(dp, FTAG);
1713                 return (err);
1714         }
1715 
1716         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1717         if (dd->dd_myname[0] == '$') {
1718                 dsl_dir_rele(dd, FTAG);
1719                 dsl_pool_config_exit(dp, FTAG);
1720                 return (0);
1721         }
1722 
1723         thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
1724         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1725 
1726         /*
1727          * Iterate over all children.
1728          */
1729         if (flags & DS_FIND_CHILDREN) {
1730                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1731                     dsl_dir_phys(dd)->dd_child_dir_zapobj);
1732                     zap_cursor_retrieve(&zc, attr) == 0;
1733                     (void) zap_cursor_advance(&zc)) {
1734                         ASSERT3U(attr->za_integer_length, ==,
1735                             sizeof (uint64_t));
1736                         ASSERT3U(attr->za_num_integers, ==, 1);
1737 
1738                         child = kmem_asprintf("%s/%s", name, attr->za_name);
1739                         dsl_pool_config_exit(dp, FTAG);
1740                         err = dmu_objset_find_impl(spa, child,
1741                             func, arg, flags);
1742                         dsl_pool_config_enter(dp, FTAG);
1743                         strfree(child);
1744                         if (err != 0)
1745                                 break;
1746                 }
1747                 zap_cursor_fini(&zc);
1748 
1749                 if (err != 0) {
1750                         dsl_dir_rele(dd, FTAG);
1751                         dsl_pool_config_exit(dp, FTAG);
1752                         kmem_free(attr, sizeof (zap_attribute_t));
1753                         return (err);
1754                 }
1755         }
1756 
1757         /*
1758          * Iterate over all snapshots.
1759          */
1760         if (flags & DS_FIND_SNAPSHOTS) {
1761                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1762 
1763                 if (err == 0) {
1764                         uint64_t snapobj;
1765 
1766                         snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
1767                         dsl_dataset_rele(ds, FTAG);
1768 
1769                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1770                             zap_cursor_retrieve(&zc, attr) == 0;
1771                             (void) zap_cursor_advance(&zc)) {
1772                                 ASSERT3U(attr->za_integer_length, ==,
1773                                     sizeof (uint64_t));
1774                                 ASSERT3U(attr->za_num_integers, ==, 1);
1775 
1776                                 child = kmem_asprintf("%s@%s",
1777                                     name, attr->za_name);
1778                                 dsl_pool_config_exit(dp, FTAG);
1779                                 err = func(child, arg);
1780                                 dsl_pool_config_enter(dp, FTAG);
1781                                 strfree(child);
1782                                 if (err != 0)
1783                                         break;
1784                         }
1785                         zap_cursor_fini(&zc);
1786                 }
1787         }
1788 
1789         dsl_dir_rele(dd, FTAG);
1790         kmem_free(attr, sizeof (zap_attribute_t));
1791         dsl_pool_config_exit(dp, FTAG);
1792 
1793         if (err != 0)
1794                 return (err);
1795 
1796         /* Apply to self. */
1797         return (func(name, arg));
1798 }
1799 
1800 /*
1801  * See comment above dmu_objset_find_impl().
1802  */
1803 int
1804 dmu_objset_find(char *name, int func(const char *, void *), void *arg,
1805     int flags)
1806 {
1807         spa_t *spa;
1808         int error;
1809 
1810         error = spa_open(name, &spa, FTAG);
1811         if (error != 0)
1812                 return (error);
1813         error = dmu_objset_find_impl(spa, name, func, arg, flags);
1814         spa_close(spa, FTAG);
1815         return (error);
1816 }
1817 
1818 void
1819 dmu_objset_set_user(objset_t *os, void *user_ptr)
1820 {
1821         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1822         os->os_user_ptr = user_ptr;
1823 }
1824 
1825 void *
1826 dmu_objset_get_user(objset_t *os)
1827 {
1828         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1829         return (os->os_user_ptr);
1830 }
1831 
1832 /*
1833  * Determine name of filesystem, given name of snapshot.
1834  * buf must be at least MAXNAMELEN bytes
1835  */
1836 int
1837 dmu_fsname(const char *snapname, char *buf)
1838 {
1839         char *atp = strchr(snapname, '@');
1840         if (atp == NULL)
1841                 return (SET_ERROR(EINVAL));
1842         if (atp - snapname >= MAXNAMELEN)
1843                 return (SET_ERROR(ENAMETOOLONG));
1844         (void) strlcpy(buf, snapname, atp - snapname + 1);
1845         return (0);
1846 }