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         dmu_objset_evict_dbufs(os);
 686 
 687         mutex_enter(&os->os_lock);
 688         spa_evicting_os_register(os->os_spa, os);
 689         if (list_is_empty(&os->os_dnodes)) {
 690                 mutex_exit(&os->os_lock);
 691                 dmu_objset_evict_done(os);
 692         } else {
 693                 mutex_exit(&os->os_lock);
 694         }
 695 }
 696 
 697 void
 698 dmu_objset_evict_done(objset_t *os)
 699 {
 700         ASSERT3P(list_head(&os->os_dnodes), ==, NULL);
 701 
 702         dnode_special_close(&os->os_meta_dnode);
 703         if (DMU_USERUSED_DNODE(os)) {
 704                 dnode_special_close(&os->os_userused_dnode);
 705                 dnode_special_close(&os->os_groupused_dnode);
 706         }
 707         zil_free(os->os_zil);
 708 
 709         VERIFY(arc_buf_remove_ref(os->os_phys_buf, &os->os_phys_buf));
 710 
 711         /*
 712          * This is a barrier to prevent the objset from going away in
 713          * dnode_move() until we can safely ensure that the objset is still in
 714          * use. We consider the objset valid before the barrier and invalid
 715          * after the barrier.
 716          */
 717         rw_enter(&os_lock, RW_READER);
 718         rw_exit(&os_lock);
 719 
 720         mutex_destroy(&os->os_lock);
 721         mutex_destroy(&os->os_obj_lock);
 722         mutex_destroy(&os->os_user_ptr_lock);
 723         spa_evicting_os_deregister(os->os_spa, os);
 724         kmem_free(os, sizeof (objset_t));
 725 }
 726 
 727 timestruc_t
 728 dmu_objset_snap_cmtime(objset_t *os)
 729 {
 730         return (dsl_dir_snap_cmtime(os->os_dsl_dataset->ds_dir));
 731 }
 732 
 733 /* called from dsl for meta-objset */
 734 objset_t *
 735 dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 736     dmu_objset_type_t type, dmu_tx_t *tx)
 737 {
 738         objset_t *os;
 739         dnode_t *mdn;
 740 
 741         ASSERT(dmu_tx_is_syncing(tx));
 742 
 743         if (ds != NULL)
 744                 VERIFY0(dmu_objset_from_ds(ds, &os));
 745         else
 746                 VERIFY0(dmu_objset_open_impl(spa, NULL, bp, &os));
 747 
 748         mdn = DMU_META_DNODE(os);
 749 
 750         dnode_allocate(mdn, DMU_OT_DNODE, 1 << DNODE_BLOCK_SHIFT,
 751             DN_MAX_INDBLKSHIFT, DMU_OT_NONE, 0, tx);
 752 
 753         /*
 754          * We don't want to have to increase the meta-dnode's nlevels
 755          * later, because then we could do it in quescing context while
 756          * we are also accessing it in open context.
 757          *
 758          * This precaution is not necessary for the MOS (ds == NULL),
 759          * because the MOS is only updated in syncing context.
 760          * This is most fortunate: the MOS is the only objset that
 761          * needs to be synced multiple times as spa_sync() iterates
 762          * to convergence, so minimizing its dn_nlevels matters.
 763          */
 764         if (ds != NULL) {
 765                 int levels = 1;
 766 
 767                 /*
 768                  * Determine the number of levels necessary for the meta-dnode
 769                  * to contain DN_MAX_OBJECT dnodes.
 770                  */
 771                 while ((uint64_t)mdn->dn_nblkptr << (mdn->dn_datablkshift +
 772                     (levels - 1) * (mdn->dn_indblkshift - SPA_BLKPTRSHIFT)) <
 773                     DN_MAX_OBJECT * sizeof (dnode_phys_t))
 774                         levels++;
 775 
 776                 mdn->dn_next_nlevels[tx->tx_txg & TXG_MASK] =
 777                     mdn->dn_nlevels = levels;
 778         }
 779 
 780         ASSERT(type != DMU_OST_NONE);
 781         ASSERT(type != DMU_OST_ANY);
 782         ASSERT(type < DMU_OST_NUMTYPES);
 783         os->os_phys->os_type = type;
 784         if (dmu_objset_userused_enabled(os)) {
 785                 os->os_phys->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
 786                 os->os_flags = os->os_phys->os_flags;
 787         }
 788 
 789         dsl_dataset_dirty(ds, tx);
 790 
 791         return (os);
 792 }
 793 
 794 typedef struct dmu_objset_create_arg {
 795         const char *doca_name;
 796         cred_t *doca_cred;
 797         void (*doca_userfunc)(objset_t *os, void *arg,
 798             cred_t *cr, dmu_tx_t *tx);
 799         void *doca_userarg;
 800         dmu_objset_type_t doca_type;
 801         uint64_t doca_flags;
 802 } dmu_objset_create_arg_t;
 803 
 804 /*ARGSUSED*/
 805 static int
 806 dmu_objset_create_check(void *arg, dmu_tx_t *tx)
 807 {
 808         dmu_objset_create_arg_t *doca = arg;
 809         dsl_pool_t *dp = dmu_tx_pool(tx);
 810         dsl_dir_t *pdd;
 811         const char *tail;
 812         int error;
 813 
 814         if (strchr(doca->doca_name, '@') != NULL)
 815                 return (SET_ERROR(EINVAL));
 816 
 817         error = dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail);
 818         if (error != 0)
 819                 return (error);
 820         if (tail == NULL) {
 821                 dsl_dir_rele(pdd, FTAG);
 822                 return (SET_ERROR(EEXIST));
 823         }
 824         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 825             doca->doca_cred);
 826         dsl_dir_rele(pdd, FTAG);
 827 
 828         return (error);
 829 }
 830 
 831 static void
 832 dmu_objset_create_sync(void *arg, dmu_tx_t *tx)
 833 {
 834         dmu_objset_create_arg_t *doca = arg;
 835         dsl_pool_t *dp = dmu_tx_pool(tx);
 836         dsl_dir_t *pdd;
 837         const char *tail;
 838         dsl_dataset_t *ds;
 839         uint64_t obj;
 840         blkptr_t *bp;
 841         objset_t *os;
 842 
 843         VERIFY0(dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail));
 844 
 845         obj = dsl_dataset_create_sync(pdd, tail, NULL, doca->doca_flags,
 846             doca->doca_cred, tx);
 847 
 848         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 849         bp = dsl_dataset_get_blkptr(ds);
 850         os = dmu_objset_create_impl(pdd->dd_pool->dp_spa,
 851             ds, bp, doca->doca_type, tx);
 852 
 853         if (doca->doca_userfunc != NULL) {
 854                 doca->doca_userfunc(os, doca->doca_userarg,
 855                     doca->doca_cred, tx);
 856         }
 857 
 858         spa_history_log_internal_ds(ds, "create", tx, "");
 859         dsl_dataset_rele(ds, FTAG);
 860         dsl_dir_rele(pdd, FTAG);
 861 }
 862 
 863 int
 864 dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
 865     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg)
 866 {
 867         dmu_objset_create_arg_t doca;
 868 
 869         doca.doca_name = name;
 870         doca.doca_cred = CRED();
 871         doca.doca_flags = flags;
 872         doca.doca_userfunc = func;
 873         doca.doca_userarg = arg;
 874         doca.doca_type = type;
 875 
 876         return (dsl_sync_task(name,
 877             dmu_objset_create_check, dmu_objset_create_sync, &doca,
 878             5, ZFS_SPACE_CHECK_NORMAL));
 879 }
 880 
 881 typedef struct dmu_objset_clone_arg {
 882         const char *doca_clone;
 883         const char *doca_origin;
 884         cred_t *doca_cred;
 885 } dmu_objset_clone_arg_t;
 886 
 887 /*ARGSUSED*/
 888 static int
 889 dmu_objset_clone_check(void *arg, dmu_tx_t *tx)
 890 {
 891         dmu_objset_clone_arg_t *doca = arg;
 892         dsl_dir_t *pdd;
 893         const char *tail;
 894         int error;
 895         dsl_dataset_t *origin;
 896         dsl_pool_t *dp = dmu_tx_pool(tx);
 897 
 898         if (strchr(doca->doca_clone, '@') != NULL)
 899                 return (SET_ERROR(EINVAL));
 900 
 901         error = dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail);
 902         if (error != 0)
 903                 return (error);
 904         if (tail == NULL) {
 905                 dsl_dir_rele(pdd, FTAG);
 906                 return (SET_ERROR(EEXIST));
 907         }
 908 
 909         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 910             doca->doca_cred);
 911         if (error != 0) {
 912                 dsl_dir_rele(pdd, FTAG);
 913                 return (SET_ERROR(EDQUOT));
 914         }
 915         dsl_dir_rele(pdd, FTAG);
 916 
 917         error = dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin);
 918         if (error != 0)
 919                 return (error);
 920 
 921         /* You can only clone snapshots, not the head datasets. */
 922         if (!origin->ds_is_snapshot) {
 923                 dsl_dataset_rele(origin, FTAG);
 924                 return (SET_ERROR(EINVAL));
 925         }
 926         dsl_dataset_rele(origin, FTAG);
 927 
 928         return (0);
 929 }
 930 
 931 static void
 932 dmu_objset_clone_sync(void *arg, dmu_tx_t *tx)
 933 {
 934         dmu_objset_clone_arg_t *doca = arg;
 935         dsl_pool_t *dp = dmu_tx_pool(tx);
 936         dsl_dir_t *pdd;
 937         const char *tail;
 938         dsl_dataset_t *origin, *ds;
 939         uint64_t obj;
 940         char namebuf[MAXNAMELEN];
 941 
 942         VERIFY0(dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail));
 943         VERIFY0(dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin));
 944 
 945         obj = dsl_dataset_create_sync(pdd, tail, origin, 0,
 946             doca->doca_cred, tx);
 947 
 948         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 949         dsl_dataset_name(origin, namebuf);
 950         spa_history_log_internal_ds(ds, "clone", tx,
 951             "origin=%s (%llu)", namebuf, origin->ds_object);
 952         dsl_dataset_rele(ds, FTAG);
 953         dsl_dataset_rele(origin, FTAG);
 954         dsl_dir_rele(pdd, FTAG);
 955 }
 956 
 957 int
 958 dmu_objset_clone(const char *clone, const char *origin)
 959 {
 960         dmu_objset_clone_arg_t doca;
 961 
 962         doca.doca_clone = clone;
 963         doca.doca_origin = origin;
 964         doca.doca_cred = CRED();
 965 
 966         return (dsl_sync_task(clone,
 967             dmu_objset_clone_check, dmu_objset_clone_sync, &doca,
 968             5, ZFS_SPACE_CHECK_NORMAL));
 969 }
 970 
 971 int
 972 dmu_objset_snapshot_one(const char *fsname, const char *snapname)
 973 {
 974         int err;
 975         char *longsnap = kmem_asprintf("%s@%s", fsname, snapname);
 976         nvlist_t *snaps = fnvlist_alloc();
 977 
 978         fnvlist_add_boolean(snaps, longsnap);
 979         strfree(longsnap);
 980         err = dsl_dataset_snapshot(snaps, NULL, NULL);
 981         fnvlist_free(snaps);
 982         return (err);
 983 }
 984 
 985 static void
 986 dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
 987 {
 988         dnode_t *dn;
 989 
 990         while (dn = list_head(list)) {
 991                 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
 992                 ASSERT(dn->dn_dbuf->db_data_pending);
 993                 /*
 994                  * Initialize dn_zio outside dnode_sync() because the
 995                  * meta-dnode needs to set it ouside dnode_sync().
 996                  */
 997                 dn->dn_zio = dn->dn_dbuf->db_data_pending->dr_zio;
 998                 ASSERT(dn->dn_zio);
 999 
1000                 ASSERT3U(dn->dn_nlevels, <=, DN_MAX_LEVELS);
1001                 list_remove(list, dn);
1002 
1003                 if (newlist) {
1004                         (void) dnode_add_ref(dn, newlist);
1005                         list_insert_tail(newlist, dn);
1006                 }
1007 
1008                 dnode_sync(dn, tx);
1009         }
1010 }
1011 
1012 /* ARGSUSED */
1013 static void
1014 dmu_objset_write_ready(zio_t *zio, arc_buf_t *abuf, void *arg)
1015 {
1016         blkptr_t *bp = zio->io_bp;
1017         objset_t *os = arg;
1018         dnode_phys_t *dnp = &os->os_phys->os_meta_dnode;
1019 
1020         ASSERT(!BP_IS_EMBEDDED(bp));
1021         ASSERT3P(bp, ==, os->os_rootbp);
1022         ASSERT3U(BP_GET_TYPE(bp), ==, DMU_OT_OBJSET);
1023         ASSERT0(BP_GET_LEVEL(bp));
1024 
1025         /*
1026          * Update rootbp fill count: it should be the number of objects
1027          * allocated in the object set (not counting the "special"
1028          * objects that are stored in the objset_phys_t -- the meta
1029          * dnode and user/group accounting objects).
1030          */
1031         bp->blk_fill = 0;
1032         for (int i = 0; i < dnp->dn_nblkptr; i++)
1033                 bp->blk_fill += BP_GET_FILL(&dnp->dn_blkptr[i]);
1034 }
1035 
1036 /* ARGSUSED */
1037 static void
1038 dmu_objset_write_done(zio_t *zio, arc_buf_t *abuf, void *arg)
1039 {
1040         blkptr_t *bp = zio->io_bp;
1041         blkptr_t *bp_orig = &zio->io_bp_orig;
1042         objset_t *os = arg;
1043 
1044         if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
1045                 ASSERT(BP_EQUAL(bp, bp_orig));
1046         } else {
1047                 dsl_dataset_t *ds = os->os_dsl_dataset;
1048                 dmu_tx_t *tx = os->os_synctx;
1049 
1050                 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
1051                 dsl_dataset_block_born(ds, bp, tx);
1052         }
1053 }
1054 
1055 /* called from dsl */
1056 void
1057 dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
1058 {
1059         int txgoff;
1060         zbookmark_phys_t zb;
1061         zio_prop_t zp;
1062         zio_t *zio;
1063         list_t *list;
1064         list_t *newlist = NULL;
1065         dbuf_dirty_record_t *dr;
1066 
1067         dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
1068 
1069         ASSERT(dmu_tx_is_syncing(tx));
1070         /* XXX the write_done callback should really give us the tx... */
1071         os->os_synctx = tx;
1072 
1073         if (os->os_dsl_dataset == NULL) {
1074                 /*
1075                  * This is the MOS.  If we have upgraded,
1076                  * spa_max_replication() could change, so reset
1077                  * os_copies here.
1078                  */
1079                 os->os_copies = spa_max_replication(os->os_spa);
1080         }
1081 
1082         /*
1083          * Create the root block IO
1084          */
1085         SET_BOOKMARK(&zb, os->os_dsl_dataset ?
1086             os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
1087             ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
1088         arc_release(os->os_phys_buf, &os->os_phys_buf);
1089 
1090         dmu_write_policy(os, NULL, 0, 0, &zp);
1091 
1092         zio = arc_write(pio, os->os_spa, tx->tx_txg,
1093             os->os_rootbp, os->os_phys_buf, DMU_OS_IS_L2CACHEABLE(os),
1094             DMU_OS_IS_L2COMPRESSIBLE(os), &zp, dmu_objset_write_ready,
1095             NULL, dmu_objset_write_done, os, ZIO_PRIORITY_ASYNC_WRITE,
1096             ZIO_FLAG_MUSTSUCCEED, &zb);
1097 
1098         /*
1099          * Sync special dnodes - the parent IO for the sync is the root block
1100          */
1101         DMU_META_DNODE(os)->dn_zio = zio;
1102         dnode_sync(DMU_META_DNODE(os), tx);
1103 
1104         os->os_phys->os_flags = os->os_flags;
1105 
1106         if (DMU_USERUSED_DNODE(os) &&
1107             DMU_USERUSED_DNODE(os)->dn_type != DMU_OT_NONE) {
1108                 DMU_USERUSED_DNODE(os)->dn_zio = zio;
1109                 dnode_sync(DMU_USERUSED_DNODE(os), tx);
1110                 DMU_GROUPUSED_DNODE(os)->dn_zio = zio;
1111                 dnode_sync(DMU_GROUPUSED_DNODE(os), tx);
1112         }
1113 
1114         txgoff = tx->tx_txg & TXG_MASK;
1115 
1116         if (dmu_objset_userused_enabled(os)) {
1117                 newlist = &os->os_synced_dnodes;
1118                 /*
1119                  * We must create the list here because it uses the
1120                  * dn_dirty_link[] of this txg.
1121                  */
1122                 list_create(newlist, sizeof (dnode_t),
1123                     offsetof(dnode_t, dn_dirty_link[txgoff]));
1124         }
1125 
1126         dmu_objset_sync_dnodes(&os->os_free_dnodes[txgoff], newlist, tx);
1127         dmu_objset_sync_dnodes(&os->os_dirty_dnodes[txgoff], newlist, tx);
1128 
1129         list = &DMU_META_DNODE(os)->dn_dirty_records[txgoff];
1130         while (dr = list_head(list)) {
1131                 ASSERT0(dr->dr_dbuf->db_level);
1132                 list_remove(list, dr);
1133                 if (dr->dr_zio)
1134                         zio_nowait(dr->dr_zio);
1135         }
1136         /*
1137          * Free intent log blocks up to this tx.
1138          */
1139         zil_sync(os->os_zil, tx);
1140         os->os_phys->os_zil_header = os->os_zil_header;
1141         zio_nowait(zio);
1142 }
1143 
1144 boolean_t
1145 dmu_objset_is_dirty(objset_t *os, uint64_t txg)
1146 {
1147         return (!list_is_empty(&os->os_dirty_dnodes[txg & TXG_MASK]) ||
1148             !list_is_empty(&os->os_free_dnodes[txg & TXG_MASK]));
1149 }
1150 
1151 static objset_used_cb_t *used_cbs[DMU_OST_NUMTYPES];
1152 
1153 void
1154 dmu_objset_register_type(dmu_objset_type_t ost, objset_used_cb_t *cb)
1155 {
1156         used_cbs[ost] = cb;
1157 }
1158 
1159 boolean_t
1160 dmu_objset_userused_enabled(objset_t *os)
1161 {
1162         return (spa_version(os->os_spa) >= SPA_VERSION_USERSPACE &&
1163             used_cbs[os->os_phys->os_type] != NULL &&
1164             DMU_USERUSED_DNODE(os) != NULL);
1165 }
1166 
1167 static void
1168 do_userquota_update(objset_t *os, uint64_t used, uint64_t flags,
1169     uint64_t user, uint64_t group, boolean_t subtract, dmu_tx_t *tx)
1170 {
1171         if ((flags & DNODE_FLAG_USERUSED_ACCOUNTED)) {
1172                 int64_t delta = DNODE_SIZE + used;
1173                 if (subtract)
1174                         delta = -delta;
1175                 VERIFY3U(0, ==, zap_increment_int(os, DMU_USERUSED_OBJECT,
1176                     user, delta, tx));
1177                 VERIFY3U(0, ==, zap_increment_int(os, DMU_GROUPUSED_OBJECT,
1178                     group, delta, tx));
1179         }
1180 }
1181 
1182 void
1183 dmu_objset_do_userquota_updates(objset_t *os, dmu_tx_t *tx)
1184 {
1185         dnode_t *dn;
1186         list_t *list = &os->os_synced_dnodes;
1187 
1188         ASSERT(list_head(list) == NULL || dmu_objset_userused_enabled(os));
1189 
1190         while (dn = list_head(list)) {
1191                 int flags;
1192                 ASSERT(!DMU_OBJECT_IS_SPECIAL(dn->dn_object));
1193                 ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE ||
1194                     dn->dn_phys->dn_flags &
1195                     DNODE_FLAG_USERUSED_ACCOUNTED);
1196 
1197                 /* Allocate the user/groupused objects if necessary. */
1198                 if (DMU_USERUSED_DNODE(os)->dn_type == DMU_OT_NONE) {
1199                         VERIFY(0 == zap_create_claim(os,
1200                             DMU_USERUSED_OBJECT,
1201                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1202                         VERIFY(0 == zap_create_claim(os,
1203                             DMU_GROUPUSED_OBJECT,
1204                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1205                 }
1206 
1207                 /*
1208                  * We intentionally modify the zap object even if the
1209                  * net delta is zero.  Otherwise
1210                  * the block of the zap obj could be shared between
1211                  * datasets but need to be different between them after
1212                  * a bprewrite.
1213                  */
1214 
1215                 flags = dn->dn_id_flags;
1216                 ASSERT(flags);
1217                 if (flags & DN_ID_OLD_EXIST)  {
1218                         do_userquota_update(os, dn->dn_oldused, dn->dn_oldflags,
1219                             dn->dn_olduid, dn->dn_oldgid, B_TRUE, tx);
1220                 }
1221                 if (flags & DN_ID_NEW_EXIST) {
1222                         do_userquota_update(os, DN_USED_BYTES(dn->dn_phys),
1223                             dn->dn_phys->dn_flags,  dn->dn_newuid,
1224                             dn->dn_newgid, B_FALSE, tx);
1225                 }
1226 
1227                 mutex_enter(&dn->dn_mtx);
1228                 dn->dn_oldused = 0;
1229                 dn->dn_oldflags = 0;
1230                 if (dn->dn_id_flags & DN_ID_NEW_EXIST) {
1231                         dn->dn_olduid = dn->dn_newuid;
1232                         dn->dn_oldgid = dn->dn_newgid;
1233                         dn->dn_id_flags |= DN_ID_OLD_EXIST;
1234                         if (dn->dn_bonuslen == 0)
1235                                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1236                         else
1237                                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1238                 }
1239                 dn->dn_id_flags &= ~(DN_ID_NEW_EXIST);
1240                 mutex_exit(&dn->dn_mtx);
1241 
1242                 list_remove(list, dn);
1243                 dnode_rele(dn, list);
1244         }
1245 }
1246 
1247 /*
1248  * Returns a pointer to data to find uid/gid from
1249  *
1250  * If a dirty record for transaction group that is syncing can't
1251  * be found then NULL is returned.  In the NULL case it is assumed
1252  * the uid/gid aren't changing.
1253  */
1254 static void *
1255 dmu_objset_userquota_find_data(dmu_buf_impl_t *db, dmu_tx_t *tx)
1256 {
1257         dbuf_dirty_record_t *dr, **drp;
1258         void *data;
1259 
1260         if (db->db_dirtycnt == 0)
1261                 return (db->db.db_data);  /* Nothing is changing */
1262 
1263         for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1264                 if (dr->dr_txg == tx->tx_txg)
1265                         break;
1266 
1267         if (dr == NULL) {
1268                 data = NULL;
1269         } else {
1270                 dnode_t *dn;
1271 
1272                 DB_DNODE_ENTER(dr->dr_dbuf);
1273                 dn = DB_DNODE(dr->dr_dbuf);
1274 
1275                 if (dn->dn_bonuslen == 0 &&
1276                     dr->dr_dbuf->db_blkid == DMU_SPILL_BLKID)
1277                         data = dr->dt.dl.dr_data->b_data;
1278                 else
1279                         data = dr->dt.dl.dr_data;
1280 
1281                 DB_DNODE_EXIT(dr->dr_dbuf);
1282         }
1283 
1284         return (data);
1285 }
1286 
1287 void
1288 dmu_objset_userquota_get_ids(dnode_t *dn, boolean_t before, dmu_tx_t *tx)
1289 {
1290         objset_t *os = dn->dn_objset;
1291         void *data = NULL;
1292         dmu_buf_impl_t *db = NULL;
1293         uint64_t *user = NULL;
1294         uint64_t *group = NULL;
1295         int flags = dn->dn_id_flags;
1296         int error;
1297         boolean_t have_spill = B_FALSE;
1298 
1299         if (!dmu_objset_userused_enabled(dn->dn_objset))
1300                 return;
1301 
1302         if (before && (flags & (DN_ID_CHKED_BONUS|DN_ID_OLD_EXIST|
1303             DN_ID_CHKED_SPILL)))
1304                 return;
1305 
1306         if (before && dn->dn_bonuslen != 0)
1307                 data = DN_BONUS(dn->dn_phys);
1308         else if (!before && dn->dn_bonuslen != 0) {
1309                 if (dn->dn_bonus) {
1310                         db = dn->dn_bonus;
1311                         mutex_enter(&db->db_mtx);
1312                         data = dmu_objset_userquota_find_data(db, tx);
1313                 } else {
1314                         data = DN_BONUS(dn->dn_phys);
1315                 }
1316         } else if (dn->dn_bonuslen == 0 && dn->dn_bonustype == DMU_OT_SA) {
1317                         int rf = 0;
1318 
1319                         if (RW_WRITE_HELD(&dn->dn_struct_rwlock))
1320                                 rf |= DB_RF_HAVESTRUCT;
1321                         error = dmu_spill_hold_by_dnode(dn,
1322                             rf | DB_RF_MUST_SUCCEED,
1323                             FTAG, (dmu_buf_t **)&db);
1324                         ASSERT(error == 0);
1325                         mutex_enter(&db->db_mtx);
1326                         data = (before) ? db->db.db_data :
1327                             dmu_objset_userquota_find_data(db, tx);
1328                         have_spill = B_TRUE;
1329         } else {
1330                 mutex_enter(&dn->dn_mtx);
1331                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1332                 mutex_exit(&dn->dn_mtx);
1333                 return;
1334         }
1335 
1336         if (before) {
1337                 ASSERT(data);
1338                 user = &dn->dn_olduid;
1339                 group = &dn->dn_oldgid;
1340         } else if (data) {
1341                 user = &dn->dn_newuid;
1342                 group = &dn->dn_newgid;
1343         }
1344 
1345         /*
1346          * Must always call the callback in case the object
1347          * type has changed and that type isn't an object type to track
1348          */
1349         error = used_cbs[os->os_phys->os_type](dn->dn_bonustype, data,
1350             user, group);
1351 
1352         /*
1353          * Preserve existing uid/gid when the callback can't determine
1354          * what the new uid/gid are and the callback returned EEXIST.
1355          * The EEXIST error tells us to just use the existing uid/gid.
1356          * If we don't know what the old values are then just assign
1357          * them to 0, since that is a new file  being created.
1358          */
1359         if (!before && data == NULL && error == EEXIST) {
1360                 if (flags & DN_ID_OLD_EXIST) {
1361                         dn->dn_newuid = dn->dn_olduid;
1362                         dn->dn_newgid = dn->dn_oldgid;
1363                 } else {
1364                         dn->dn_newuid = 0;
1365                         dn->dn_newgid = 0;
1366                 }
1367                 error = 0;
1368         }
1369 
1370         if (db)
1371                 mutex_exit(&db->db_mtx);
1372 
1373         mutex_enter(&dn->dn_mtx);
1374         if (error == 0 && before)
1375                 dn->dn_id_flags |= DN_ID_OLD_EXIST;
1376         if (error == 0 && !before)
1377                 dn->dn_id_flags |= DN_ID_NEW_EXIST;
1378 
1379         if (have_spill) {
1380                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1381         } else {
1382                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1383         }
1384         mutex_exit(&dn->dn_mtx);
1385         if (have_spill)
1386                 dmu_buf_rele((dmu_buf_t *)db, FTAG);
1387 }
1388 
1389 boolean_t
1390 dmu_objset_userspace_present(objset_t *os)
1391 {
1392         return (os->os_phys->os_flags &
1393             OBJSET_FLAG_USERACCOUNTING_COMPLETE);
1394 }
1395 
1396 int
1397 dmu_objset_userspace_upgrade(objset_t *os)
1398 {
1399         uint64_t obj;
1400         int err = 0;
1401 
1402         if (dmu_objset_userspace_present(os))
1403                 return (0);
1404         if (!dmu_objset_userused_enabled(os))
1405                 return (SET_ERROR(ENOTSUP));
1406         if (dmu_objset_is_snapshot(os))
1407                 return (SET_ERROR(EINVAL));
1408 
1409         /*
1410          * We simply need to mark every object dirty, so that it will be
1411          * synced out and now accounted.  If this is called
1412          * concurrently, or if we already did some work before crashing,
1413          * that's fine, since we track each object's accounted state
1414          * independently.
1415          */
1416 
1417         for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, 0)) {
1418                 dmu_tx_t *tx;
1419                 dmu_buf_t *db;
1420                 int objerr;
1421 
1422                 if (issig(JUSTLOOKING) && issig(FORREAL))
1423                         return (SET_ERROR(EINTR));
1424 
1425                 objerr = dmu_bonus_hold(os, obj, FTAG, &db);
1426                 if (objerr != 0)
1427                         continue;
1428                 tx = dmu_tx_create(os);
1429                 dmu_tx_hold_bonus(tx, obj);
1430                 objerr = dmu_tx_assign(tx, TXG_WAIT);
1431                 if (objerr != 0) {
1432                         dmu_tx_abort(tx);
1433                         continue;
1434                 }
1435                 dmu_buf_will_dirty(db, tx);
1436                 dmu_buf_rele(db, FTAG);
1437                 dmu_tx_commit(tx);
1438         }
1439 
1440         os->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
1441         txg_wait_synced(dmu_objset_pool(os), 0);
1442         return (0);
1443 }
1444 
1445 void
1446 dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
1447     uint64_t *usedobjsp, uint64_t *availobjsp)
1448 {
1449         dsl_dataset_space(os->os_dsl_dataset, refdbytesp, availbytesp,
1450             usedobjsp, availobjsp);
1451 }
1452 
1453 uint64_t
1454 dmu_objset_fsid_guid(objset_t *os)
1455 {
1456         return (dsl_dataset_fsid_guid(os->os_dsl_dataset));
1457 }
1458 
1459 void
1460 dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat)
1461 {
1462         stat->dds_type = os->os_phys->os_type;
1463         if (os->os_dsl_dataset)
1464                 dsl_dataset_fast_stat(os->os_dsl_dataset, stat);
1465 }
1466 
1467 void
1468 dmu_objset_stats(objset_t *os, nvlist_t *nv)
1469 {
1470         ASSERT(os->os_dsl_dataset ||
1471             os->os_phys->os_type == DMU_OST_META);
1472 
1473         if (os->os_dsl_dataset != NULL)
1474                 dsl_dataset_stats(os->os_dsl_dataset, nv);
1475 
1476         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_TYPE,
1477             os->os_phys->os_type);
1478         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERACCOUNTING,
1479             dmu_objset_userspace_present(os));
1480 }
1481 
1482 int
1483 dmu_objset_is_snapshot(objset_t *os)
1484 {
1485         if (os->os_dsl_dataset != NULL)
1486                 return (os->os_dsl_dataset->ds_is_snapshot);
1487         else
1488                 return (B_FALSE);
1489 }
1490 
1491 int
1492 dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen,
1493     boolean_t *conflict)
1494 {
1495         dsl_dataset_t *ds = os->os_dsl_dataset;
1496         uint64_t ignored;
1497 
1498         if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
1499                 return (SET_ERROR(ENOENT));
1500 
1501         return (zap_lookup_norm(ds->ds_dir->dd_pool->dp_meta_objset,
1502             dsl_dataset_phys(ds)->ds_snapnames_zapobj, name, 8, 1, &ignored,
1503             MT_FIRST, real, maxlen, conflict));
1504 }
1505 
1506 int
1507 dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
1508     uint64_t *idp, uint64_t *offp, boolean_t *case_conflict)
1509 {
1510         dsl_dataset_t *ds = os->os_dsl_dataset;
1511         zap_cursor_t cursor;
1512         zap_attribute_t attr;
1513 
1514         ASSERT(dsl_pool_config_held(dmu_objset_pool(os)));
1515 
1516         if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
1517                 return (SET_ERROR(ENOENT));
1518 
1519         zap_cursor_init_serialized(&cursor,
1520             ds->ds_dir->dd_pool->dp_meta_objset,
1521             dsl_dataset_phys(ds)->ds_snapnames_zapobj, *offp);
1522 
1523         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1524                 zap_cursor_fini(&cursor);
1525                 return (SET_ERROR(ENOENT));
1526         }
1527 
1528         if (strlen(attr.za_name) + 1 > namelen) {
1529                 zap_cursor_fini(&cursor);
1530                 return (SET_ERROR(ENAMETOOLONG));
1531         }
1532 
1533         (void) strcpy(name, attr.za_name);
1534         if (idp)
1535                 *idp = attr.za_first_integer;
1536         if (case_conflict)
1537                 *case_conflict = attr.za_normalization_conflict;
1538         zap_cursor_advance(&cursor);
1539         *offp = zap_cursor_serialize(&cursor);
1540         zap_cursor_fini(&cursor);
1541 
1542         return (0);
1543 }
1544 
1545 int
1546 dmu_dir_list_next(objset_t *os, int namelen, char *name,
1547     uint64_t *idp, uint64_t *offp)
1548 {
1549         dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
1550         zap_cursor_t cursor;
1551         zap_attribute_t attr;
1552 
1553         /* there is no next dir on a snapshot! */
1554         if (os->os_dsl_dataset->ds_object !=
1555             dsl_dir_phys(dd)->dd_head_dataset_obj)
1556                 return (SET_ERROR(ENOENT));
1557 
1558         zap_cursor_init_serialized(&cursor,
1559             dd->dd_pool->dp_meta_objset,
1560             dsl_dir_phys(dd)->dd_child_dir_zapobj, *offp);
1561 
1562         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1563                 zap_cursor_fini(&cursor);
1564                 return (SET_ERROR(ENOENT));
1565         }
1566 
1567         if (strlen(attr.za_name) + 1 > namelen) {
1568                 zap_cursor_fini(&cursor);
1569                 return (SET_ERROR(ENAMETOOLONG));
1570         }
1571 
1572         (void) strcpy(name, attr.za_name);
1573         if (idp)
1574                 *idp = attr.za_first_integer;
1575         zap_cursor_advance(&cursor);
1576         *offp = zap_cursor_serialize(&cursor);
1577         zap_cursor_fini(&cursor);
1578 
1579         return (0);
1580 }
1581 
1582 /*
1583  * Find objsets under and including ddobj, call func(ds) on each.
1584  */
1585 int
1586 dmu_objset_find_dp(dsl_pool_t *dp, uint64_t ddobj,
1587     int func(dsl_pool_t *, dsl_dataset_t *, void *), void *arg, int flags)
1588 {
1589         dsl_dir_t *dd;
1590         dsl_dataset_t *ds;
1591         zap_cursor_t zc;
1592         zap_attribute_t *attr;
1593         uint64_t thisobj;
1594         int err;
1595 
1596         ASSERT(dsl_pool_config_held(dp));
1597 
1598         err = dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd);
1599         if (err != 0)
1600                 return (err);
1601 
1602         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1603         if (dd->dd_myname[0] == '$') {
1604                 dsl_dir_rele(dd, FTAG);
1605                 return (0);
1606         }
1607 
1608         thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
1609         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1610 
1611         /*
1612          * Iterate over all children.
1613          */
1614         if (flags & DS_FIND_CHILDREN) {
1615                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1616                     dsl_dir_phys(dd)->dd_child_dir_zapobj);
1617                     zap_cursor_retrieve(&zc, attr) == 0;
1618                     (void) zap_cursor_advance(&zc)) {
1619                         ASSERT3U(attr->za_integer_length, ==,
1620                             sizeof (uint64_t));
1621                         ASSERT3U(attr->za_num_integers, ==, 1);
1622 
1623                         err = dmu_objset_find_dp(dp, attr->za_first_integer,
1624                             func, arg, flags);
1625                         if (err != 0)
1626                                 break;
1627                 }
1628                 zap_cursor_fini(&zc);
1629 
1630                 if (err != 0) {
1631                         dsl_dir_rele(dd, FTAG);
1632                         kmem_free(attr, sizeof (zap_attribute_t));
1633                         return (err);
1634                 }
1635         }
1636 
1637         /*
1638          * Iterate over all snapshots.
1639          */
1640         if (flags & DS_FIND_SNAPSHOTS) {
1641                 dsl_dataset_t *ds;
1642                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1643 
1644                 if (err == 0) {
1645                         uint64_t snapobj;
1646 
1647                         snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
1648                         dsl_dataset_rele(ds, FTAG);
1649 
1650                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1651                             zap_cursor_retrieve(&zc, attr) == 0;
1652                             (void) zap_cursor_advance(&zc)) {
1653                                 ASSERT3U(attr->za_integer_length, ==,
1654                                     sizeof (uint64_t));
1655                                 ASSERT3U(attr->za_num_integers, ==, 1);
1656 
1657                                 err = dsl_dataset_hold_obj(dp,
1658                                     attr->za_first_integer, FTAG, &ds);
1659                                 if (err != 0)
1660                                         break;
1661                                 err = func(dp, ds, arg);
1662                                 dsl_dataset_rele(ds, FTAG);
1663                                 if (err != 0)
1664                                         break;
1665                         }
1666                         zap_cursor_fini(&zc);
1667                 }
1668         }
1669 
1670         dsl_dir_rele(dd, FTAG);
1671         kmem_free(attr, sizeof (zap_attribute_t));
1672 
1673         if (err != 0)
1674                 return (err);
1675 
1676         /*
1677          * Apply to self.
1678          */
1679         err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1680         if (err != 0)
1681                 return (err);
1682         err = func(dp, ds, arg);
1683         dsl_dataset_rele(ds, FTAG);
1684         return (err);
1685 }
1686 
1687 /*
1688  * Find all objsets under name, and for each, call 'func(child_name, arg)'.
1689  * The dp_config_rwlock must not be held when this is called, and it
1690  * will not be held when the callback is called.
1691  * Therefore this function should only be used when the pool is not changing
1692  * (e.g. in syncing context), or the callback can deal with the possible races.
1693  */
1694 static int
1695 dmu_objset_find_impl(spa_t *spa, const char *name,
1696     int func(const char *, void *), void *arg, int flags)
1697 {
1698         dsl_dir_t *dd;
1699         dsl_pool_t *dp = spa_get_dsl(spa);
1700         dsl_dataset_t *ds;
1701         zap_cursor_t zc;
1702         zap_attribute_t *attr;
1703         char *child;
1704         uint64_t thisobj;
1705         int err;
1706 
1707         dsl_pool_config_enter(dp, FTAG);
1708 
1709         err = dsl_dir_hold(dp, name, FTAG, &dd, NULL);
1710         if (err != 0) {
1711                 dsl_pool_config_exit(dp, FTAG);
1712                 return (err);
1713         }
1714 
1715         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1716         if (dd->dd_myname[0] == '$') {
1717                 dsl_dir_rele(dd, FTAG);
1718                 dsl_pool_config_exit(dp, FTAG);
1719                 return (0);
1720         }
1721 
1722         thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
1723         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1724 
1725         /*
1726          * Iterate over all children.
1727          */
1728         if (flags & DS_FIND_CHILDREN) {
1729                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1730                     dsl_dir_phys(dd)->dd_child_dir_zapobj);
1731                     zap_cursor_retrieve(&zc, attr) == 0;
1732                     (void) zap_cursor_advance(&zc)) {
1733                         ASSERT3U(attr->za_integer_length, ==,
1734                             sizeof (uint64_t));
1735                         ASSERT3U(attr->za_num_integers, ==, 1);
1736 
1737                         child = kmem_asprintf("%s/%s", name, attr->za_name);
1738                         dsl_pool_config_exit(dp, FTAG);
1739                         err = dmu_objset_find_impl(spa, child,
1740                             func, arg, flags);
1741                         dsl_pool_config_enter(dp, FTAG);
1742                         strfree(child);
1743                         if (err != 0)
1744                                 break;
1745                 }
1746                 zap_cursor_fini(&zc);
1747 
1748                 if (err != 0) {
1749                         dsl_dir_rele(dd, FTAG);
1750                         dsl_pool_config_exit(dp, FTAG);
1751                         kmem_free(attr, sizeof (zap_attribute_t));
1752                         return (err);
1753                 }
1754         }
1755 
1756         /*
1757          * Iterate over all snapshots.
1758          */
1759         if (flags & DS_FIND_SNAPSHOTS) {
1760                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1761 
1762                 if (err == 0) {
1763                         uint64_t snapobj;
1764 
1765                         snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
1766                         dsl_dataset_rele(ds, FTAG);
1767 
1768                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1769                             zap_cursor_retrieve(&zc, attr) == 0;
1770                             (void) zap_cursor_advance(&zc)) {
1771                                 ASSERT3U(attr->za_integer_length, ==,
1772                                     sizeof (uint64_t));
1773                                 ASSERT3U(attr->za_num_integers, ==, 1);
1774 
1775                                 child = kmem_asprintf("%s@%s",
1776                                     name, attr->za_name);
1777                                 dsl_pool_config_exit(dp, FTAG);
1778                                 err = func(child, arg);
1779                                 dsl_pool_config_enter(dp, FTAG);
1780                                 strfree(child);
1781                                 if (err != 0)
1782                                         break;
1783                         }
1784                         zap_cursor_fini(&zc);
1785                 }
1786         }
1787 
1788         dsl_dir_rele(dd, FTAG);
1789         kmem_free(attr, sizeof (zap_attribute_t));
1790         dsl_pool_config_exit(dp, FTAG);
1791 
1792         if (err != 0)
1793                 return (err);
1794 
1795         /* Apply to self. */
1796         return (func(name, arg));
1797 }
1798 
1799 /*
1800  * See comment above dmu_objset_find_impl().
1801  */
1802 int
1803 dmu_objset_find(char *name, int func(const char *, void *), void *arg,
1804     int flags)
1805 {
1806         spa_t *spa;
1807         int error;
1808 
1809         error = spa_open(name, &spa, FTAG);
1810         if (error != 0)
1811                 return (error);
1812         error = dmu_objset_find_impl(spa, name, func, arg, flags);
1813         spa_close(spa, FTAG);
1814         return (error);
1815 }
1816 
1817 void
1818 dmu_objset_set_user(objset_t *os, void *user_ptr)
1819 {
1820         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1821         os->os_user_ptr = user_ptr;
1822 }
1823 
1824 void *
1825 dmu_objset_get_user(objset_t *os)
1826 {
1827         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1828         return (os->os_user_ptr);
1829 }
1830 
1831 /*
1832  * Determine name of filesystem, given name of snapshot.
1833  * buf must be at least MAXNAMELEN bytes
1834  */
1835 int
1836 dmu_fsname(const char *snapname, char *buf)
1837 {
1838         char *atp = strchr(snapname, '@');
1839         if (atp == NULL)
1840                 return (SET_ERROR(EINVAL));
1841         if (atp - snapname >= MAXNAMELEN)
1842                 return (SET_ERROR(ENAMETOOLONG));
1843         (void) strlcpy(buf, snapname, atp - snapname + 1);
1844         return (0);
1845 }