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  */
  28 
  29 /* Portions Copyright 2010 Robert Milkowski */
  30 
  31 #include <sys/cred.h>
  32 #include <sys/zfs_context.h>
  33 #include <sys/dmu_objset.h>
  34 #include <sys/dsl_dir.h>
  35 #include <sys/dsl_dataset.h>
  36 #include <sys/dsl_prop.h>
  37 #include <sys/dsl_pool.h>
  38 #include <sys/dsl_synctask.h>
  39 #include <sys/dsl_deleg.h>
  40 #include <sys/dnode.h>
  41 #include <sys/dbuf.h>
  42 #include <sys/zvol.h>
  43 #include <sys/dmu_tx.h>
  44 #include <sys/zap.h>
  45 #include <sys/zil.h>
  46 #include <sys/dmu_impl.h>
  47 #include <sys/zfs_ioctl.h>
  48 #include <sys/sa.h>
  49 #include <sys/zfs_onexit.h>
  50 #include <sys/dsl_destroy.h>
  51 
  52 /*
  53  * Needed to close a window in dnode_move() that allows the objset to be freed
  54  * before it can be safely accessed.
  55  */
  56 krwlock_t os_lock;
  57 
  58 void
  59 dmu_objset_init(void)
  60 {
  61         rw_init(&os_lock, NULL, RW_DEFAULT, NULL);
  62 }
  63 
  64 void
  65 dmu_objset_fini(void)
  66 {
  67         rw_destroy(&os_lock);
  68 }
  69 
  70 spa_t *
  71 dmu_objset_spa(objset_t *os)
  72 {
  73         return (os->os_spa);
  74 }
  75 
  76 zilog_t *
  77 dmu_objset_zil(objset_t *os)
  78 {
  79         return (os->os_zil);
  80 }
  81 
  82 dsl_pool_t *
  83 dmu_objset_pool(objset_t *os)
  84 {
  85         dsl_dataset_t *ds;
  86 
  87         if ((ds = os->os_dsl_dataset) != NULL && ds->ds_dir)
  88                 return (ds->ds_dir->dd_pool);
  89         else
  90                 return (spa_get_dsl(os->os_spa));
  91 }
  92 
  93 dsl_dataset_t *
  94 dmu_objset_ds(objset_t *os)
  95 {
  96         return (os->os_dsl_dataset);
  97 }
  98 
  99 dmu_objset_type_t
 100 dmu_objset_type(objset_t *os)
 101 {
 102         return (os->os_phys->os_type);
 103 }
 104 
 105 void
 106 dmu_objset_name(objset_t *os, char *buf)
 107 {
 108         dsl_dataset_name(os->os_dsl_dataset, buf);
 109 }
 110 
 111 uint64_t
 112 dmu_objset_id(objset_t *os)
 113 {
 114         dsl_dataset_t *ds = os->os_dsl_dataset;
 115 
 116         return (ds ? ds->ds_object : 0);
 117 }
 118 
 119 zfs_sync_type_t
 120 dmu_objset_syncprop(objset_t *os)
 121 {
 122         return (os->os_sync);
 123 }
 124 
 125 zfs_logbias_op_t
 126 dmu_objset_logbias(objset_t *os)
 127 {
 128         return (os->os_logbias);
 129 }
 130 
 131 static void
 132 checksum_changed_cb(void *arg, uint64_t newval)
 133 {
 134         objset_t *os = arg;
 135 
 136         /*
 137          * Inheritance should have been done by now.
 138          */
 139         ASSERT(newval != ZIO_CHECKSUM_INHERIT);
 140 
 141         os->os_checksum = zio_checksum_select(newval, ZIO_CHECKSUM_ON_VALUE);
 142 }
 143 
 144 static void
 145 compression_changed_cb(void *arg, uint64_t newval)
 146 {
 147         objset_t *os = arg;
 148 
 149         /*
 150          * Inheritance and range checking should have been done by now.
 151          */
 152         ASSERT(newval != ZIO_COMPRESS_INHERIT);
 153 
 154         os->os_compress = zio_compress_select(newval, ZIO_COMPRESS_ON_VALUE);
 155 }
 156 
 157 static void
 158 copies_changed_cb(void *arg, uint64_t newval)
 159 {
 160         objset_t *os = arg;
 161 
 162         /*
 163          * Inheritance and range checking should have been done by now.
 164          */
 165         ASSERT(newval > 0);
 166         ASSERT(newval <= spa_max_replication(os->os_spa));
 167 
 168         os->os_copies = newval;
 169 }
 170 
 171 static void
 172 dedup_changed_cb(void *arg, uint64_t newval)
 173 {
 174         objset_t *os = arg;
 175         spa_t *spa = os->os_spa;
 176         enum zio_checksum checksum;
 177 
 178         /*
 179          * Inheritance should have been done by now.
 180          */
 181         ASSERT(newval != ZIO_CHECKSUM_INHERIT);
 182 
 183         checksum = zio_checksum_dedup_select(spa, newval, ZIO_CHECKSUM_OFF);
 184 
 185         os->os_dedup_checksum = checksum & ZIO_CHECKSUM_MASK;
 186         os->os_dedup_verify = !!(checksum & ZIO_CHECKSUM_VERIFY);
 187 }
 188 
 189 static void
 190 primary_cache_changed_cb(void *arg, uint64_t newval)
 191 {
 192         objset_t *os = arg;
 193 
 194         /*
 195          * Inheritance and range checking should have been done by now.
 196          */
 197         ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
 198             newval == ZFS_CACHE_METADATA);
 199 
 200         os->os_primary_cache = newval;
 201 }
 202 
 203 static void
 204 secondary_cache_changed_cb(void *arg, uint64_t newval)
 205 {
 206         objset_t *os = arg;
 207 
 208         /*
 209          * Inheritance and range checking should have been done by now.
 210          */
 211         ASSERT(newval == ZFS_CACHE_ALL || newval == ZFS_CACHE_NONE ||
 212             newval == ZFS_CACHE_METADATA);
 213 
 214         os->os_secondary_cache = newval;
 215 }
 216 
 217 static void
 218 sync_changed_cb(void *arg, uint64_t newval)
 219 {
 220         objset_t *os = arg;
 221 
 222         /*
 223          * Inheritance and range checking should have been done by now.
 224          */
 225         ASSERT(newval == ZFS_SYNC_STANDARD || newval == ZFS_SYNC_ALWAYS ||
 226             newval == ZFS_SYNC_DISABLED);
 227 
 228         os->os_sync = newval;
 229         if (os->os_zil)
 230                 zil_set_sync(os->os_zil, newval);
 231 }
 232 
 233 static void
 234 redundant_metadata_changed_cb(void *arg, uint64_t newval)
 235 {
 236         objset_t *os = arg;
 237 
 238         /*
 239          * Inheritance and range checking should have been done by now.
 240          */
 241         ASSERT(newval == ZFS_REDUNDANT_METADATA_ALL ||
 242             newval == ZFS_REDUNDANT_METADATA_MOST);
 243 
 244         os->os_redundant_metadata = newval;
 245 }
 246 
 247 static void
 248 logbias_changed_cb(void *arg, uint64_t newval)
 249 {
 250         objset_t *os = arg;
 251 
 252         ASSERT(newval == ZFS_LOGBIAS_LATENCY ||
 253             newval == ZFS_LOGBIAS_THROUGHPUT);
 254         os->os_logbias = newval;
 255         if (os->os_zil)
 256                 zil_set_logbias(os->os_zil, newval);
 257 }
 258 
 259 static void
 260 recordsize_changed_cb(void *arg, uint64_t newval)
 261 {
 262         objset_t *os = arg;
 263 
 264         os->os_recordsize = newval;
 265 }
 266 
 267 void
 268 dmu_objset_byteswap(void *buf, size_t size)
 269 {
 270         objset_phys_t *osp = buf;
 271 
 272         ASSERT(size == OBJSET_OLD_PHYS_SIZE || size == sizeof (objset_phys_t));
 273         dnode_byteswap(&osp->os_meta_dnode);
 274         byteswap_uint64_array(&osp->os_zil_header, sizeof (zil_header_t));
 275         osp->os_type = BSWAP_64(osp->os_type);
 276         osp->os_flags = BSWAP_64(osp->os_flags);
 277         if (size == sizeof (objset_phys_t)) {
 278                 dnode_byteswap(&osp->os_userused_dnode);
 279                 dnode_byteswap(&osp->os_groupused_dnode);
 280         }
 281 }
 282 
 283 int
 284 dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 285     objset_t **osp)
 286 {
 287         objset_t *os;
 288         int i, err;
 289 
 290         ASSERT(ds == NULL || MUTEX_HELD(&ds->ds_opening_lock));
 291 
 292         os = kmem_zalloc(sizeof (objset_t), KM_SLEEP);
 293         os->os_dsl_dataset = ds;
 294         os->os_spa = spa;
 295         os->os_rootbp = bp;
 296         if (!BP_IS_HOLE(os->os_rootbp)) {
 297                 arc_flags_t aflags = ARC_FLAG_WAIT;
 298                 zbookmark_phys_t zb;
 299                 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
 300                     ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
 301 
 302                 if (DMU_OS_IS_L2CACHEABLE(os))
 303                         aflags |= ARC_FLAG_L2CACHE;
 304                 if (DMU_OS_IS_L2COMPRESSIBLE(os))
 305                         aflags |= ARC_FLAG_L2COMPRESS;
 306 
 307                 dprintf_bp(os->os_rootbp, "reading %s", "");
 308                 err = arc_read(NULL, spa, os->os_rootbp,
 309                     arc_getbuf_func, &os->os_phys_buf,
 310                     ZIO_PRIORITY_SYNC_READ, ZIO_FLAG_CANFAIL, &aflags, &zb);
 311                 if (err != 0) {
 312                         kmem_free(os, sizeof (objset_t));
 313                         /* convert checksum errors into IO errors */
 314                         if (err == ECKSUM)
 315                                 err = SET_ERROR(EIO);
 316                         return (err);
 317                 }
 318 
 319                 /* Increase the blocksize if we are permitted. */
 320                 if (spa_version(spa) >= SPA_VERSION_USERSPACE &&
 321                     arc_buf_size(os->os_phys_buf) < sizeof (objset_phys_t)) {
 322                         arc_buf_t *buf = arc_buf_alloc(spa,
 323                             sizeof (objset_phys_t), &os->os_phys_buf,
 324                             ARC_BUFC_METADATA);
 325                         bzero(buf->b_data, sizeof (objset_phys_t));
 326                         bcopy(os->os_phys_buf->b_data, buf->b_data,
 327                             arc_buf_size(os->os_phys_buf));
 328                         (void) arc_buf_remove_ref(os->os_phys_buf,
 329                             &os->os_phys_buf);
 330                         os->os_phys_buf = buf;
 331                 }
 332 
 333                 os->os_phys = os->os_phys_buf->b_data;
 334                 os->os_flags = os->os_phys->os_flags;
 335         } else {
 336                 int size = spa_version(spa) >= SPA_VERSION_USERSPACE ?
 337                     sizeof (objset_phys_t) : OBJSET_OLD_PHYS_SIZE;
 338                 os->os_phys_buf = arc_buf_alloc(spa, size,
 339                     &os->os_phys_buf, ARC_BUFC_METADATA);
 340                 os->os_phys = os->os_phys_buf->b_data;
 341                 bzero(os->os_phys, size);
 342         }
 343 
 344         /*
 345          * Note: the changed_cb will be called once before the register
 346          * func returns, thus changing the checksum/compression from the
 347          * default (fletcher2/off).  Snapshots don't need to know about
 348          * checksum/compression/copies.
 349          */
 350         if (ds != NULL) {
 351                 err = dsl_prop_register(ds,
 352                     zfs_prop_to_name(ZFS_PROP_PRIMARYCACHE),
 353                     primary_cache_changed_cb, os);
 354                 if (err == 0) {
 355                         err = dsl_prop_register(ds,
 356                             zfs_prop_to_name(ZFS_PROP_SECONDARYCACHE),
 357                             secondary_cache_changed_cb, os);
 358                 }
 359                 if (!ds->ds_is_snapshot) {
 360                         if (err == 0) {
 361                                 err = dsl_prop_register(ds,
 362                                     zfs_prop_to_name(ZFS_PROP_CHECKSUM),
 363                                     checksum_changed_cb, os);
 364                         }
 365                         if (err == 0) {
 366                                 err = dsl_prop_register(ds,
 367                                     zfs_prop_to_name(ZFS_PROP_COMPRESSION),
 368                                     compression_changed_cb, os);
 369                         }
 370                         if (err == 0) {
 371                                 err = dsl_prop_register(ds,
 372                                     zfs_prop_to_name(ZFS_PROP_COPIES),
 373                                     copies_changed_cb, os);
 374                         }
 375                         if (err == 0) {
 376                                 err = dsl_prop_register(ds,
 377                                     zfs_prop_to_name(ZFS_PROP_DEDUP),
 378                                     dedup_changed_cb, os);
 379                         }
 380                         if (err == 0) {
 381                                 err = dsl_prop_register(ds,
 382                                     zfs_prop_to_name(ZFS_PROP_LOGBIAS),
 383                                     logbias_changed_cb, os);
 384                         }
 385                         if (err == 0) {
 386                                 err = dsl_prop_register(ds,
 387                                     zfs_prop_to_name(ZFS_PROP_SYNC),
 388                                     sync_changed_cb, os);
 389                         }
 390                         if (err == 0) {
 391                                 err = dsl_prop_register(ds,
 392                                     zfs_prop_to_name(
 393                                     ZFS_PROP_REDUNDANT_METADATA),
 394                                     redundant_metadata_changed_cb, os);
 395                         }
 396                         if (err == 0) {
 397                                 err = dsl_prop_register(ds,
 398                                     zfs_prop_to_name(ZFS_PROP_RECORDSIZE),
 399                                     recordsize_changed_cb, os);
 400                         }
 401                 }
 402                 if (err != 0) {
 403                         VERIFY(arc_buf_remove_ref(os->os_phys_buf,
 404                             &os->os_phys_buf));
 405                         kmem_free(os, sizeof (objset_t));
 406                         return (err);
 407                 }
 408         } else {
 409                 /* It's the meta-objset. */
 410                 os->os_checksum = ZIO_CHECKSUM_FLETCHER_4;
 411                 os->os_compress = ZIO_COMPRESS_LZJB;
 412                 os->os_copies = spa_max_replication(spa);
 413                 os->os_dedup_checksum = ZIO_CHECKSUM_OFF;
 414                 os->os_dedup_verify = B_FALSE;
 415                 os->os_logbias = ZFS_LOGBIAS_LATENCY;
 416                 os->os_sync = ZFS_SYNC_STANDARD;
 417                 os->os_primary_cache = ZFS_CACHE_ALL;
 418                 os->os_secondary_cache = ZFS_CACHE_ALL;
 419         }
 420 
 421         if (ds == NULL || !ds->ds_is_snapshot)
 422                 os->os_zil_header = os->os_phys->os_zil_header;
 423         os->os_zil = zil_alloc(os, &os->os_zil_header);
 424 
 425         for (i = 0; i < TXG_SIZE; i++) {
 426                 list_create(&os->os_dirty_dnodes[i], sizeof (dnode_t),
 427                     offsetof(dnode_t, dn_dirty_link[i]));
 428                 list_create(&os->os_free_dnodes[i], sizeof (dnode_t),
 429                     offsetof(dnode_t, dn_dirty_link[i]));
 430         }
 431         list_create(&os->os_dnodes, sizeof (dnode_t),
 432             offsetof(dnode_t, dn_link));
 433         list_create(&os->os_downgraded_dbufs, sizeof (dmu_buf_impl_t),
 434             offsetof(dmu_buf_impl_t, db_link));
 435 
 436         mutex_init(&os->os_lock, NULL, MUTEX_DEFAULT, NULL);
 437         mutex_init(&os->os_obj_lock, NULL, MUTEX_DEFAULT, NULL);
 438         mutex_init(&os->os_user_ptr_lock, NULL, MUTEX_DEFAULT, NULL);
 439 
 440         dnode_special_open(os, &os->os_phys->os_meta_dnode,
 441             DMU_META_DNODE_OBJECT, &os->os_meta_dnode);
 442         if (arc_buf_size(os->os_phys_buf) >= sizeof (objset_phys_t)) {
 443                 dnode_special_open(os, &os->os_phys->os_userused_dnode,
 444                     DMU_USERUSED_OBJECT, &os->os_userused_dnode);
 445                 dnode_special_open(os, &os->os_phys->os_groupused_dnode,
 446                     DMU_GROUPUSED_OBJECT, &os->os_groupused_dnode);
 447         }
 448 
 449         *osp = os;
 450         return (0);
 451 }
 452 
 453 int
 454 dmu_objset_from_ds(dsl_dataset_t *ds, objset_t **osp)
 455 {
 456         int err = 0;
 457 
 458         mutex_enter(&ds->ds_opening_lock);
 459         if (ds->ds_objset == NULL) {
 460                 objset_t *os;
 461                 err = dmu_objset_open_impl(dsl_dataset_get_spa(ds),
 462                     ds, dsl_dataset_get_blkptr(ds), &os);
 463 
 464                 if (err == 0) {
 465                         mutex_enter(&ds->ds_lock);
 466                         ASSERT(ds->ds_objset == NULL);
 467                         ds->ds_objset = os;
 468                         mutex_exit(&ds->ds_lock);
 469                 }
 470         }
 471         *osp = ds->ds_objset;
 472         mutex_exit(&ds->ds_opening_lock);
 473         return (err);
 474 }
 475 
 476 /*
 477  * Holds the pool while the objset is held.  Therefore only one objset
 478  * can be held at a time.
 479  */
 480 int
 481 dmu_objset_hold(const char *name, void *tag, objset_t **osp)
 482 {
 483         dsl_pool_t *dp;
 484         dsl_dataset_t *ds;
 485         int err;
 486 
 487         err = dsl_pool_hold(name, tag, &dp);
 488         if (err != 0)
 489                 return (err);
 490         err = dsl_dataset_hold(dp, name, tag, &ds);
 491         if (err != 0) {
 492                 dsl_pool_rele(dp, tag);
 493                 return (err);
 494         }
 495 
 496         err = dmu_objset_from_ds(ds, osp);
 497         if (err != 0) {
 498                 dsl_dataset_rele(ds, tag);
 499                 dsl_pool_rele(dp, tag);
 500         }
 501 
 502         return (err);
 503 }
 504 
 505 /*
 506  * dsl_pool must not be held when this is called.
 507  * Upon successful return, there will be a longhold on the dataset,
 508  * and the dsl_pool will not be held.
 509  */
 510 int
 511 dmu_objset_own(const char *name, dmu_objset_type_t type,
 512     boolean_t readonly, void *tag, objset_t **osp)
 513 {
 514         dsl_pool_t *dp;
 515         dsl_dataset_t *ds;
 516         int err;
 517 
 518         err = dsl_pool_hold(name, FTAG, &dp);
 519         if (err != 0)
 520                 return (err);
 521         err = dsl_dataset_own(dp, name, tag, &ds);
 522         if (err != 0) {
 523                 dsl_pool_rele(dp, FTAG);
 524                 return (err);
 525         }
 526 
 527         err = dmu_objset_from_ds(ds, osp);
 528         dsl_pool_rele(dp, FTAG);
 529         if (err != 0) {
 530                 dsl_dataset_disown(ds, tag);
 531         } else if (type != DMU_OST_ANY && type != (*osp)->os_phys->os_type) {
 532                 dsl_dataset_disown(ds, tag);
 533                 return (SET_ERROR(EINVAL));
 534         } else if (!readonly && ds->ds_is_snapshot) {
 535                 dsl_dataset_disown(ds, tag);
 536                 return (SET_ERROR(EROFS));
 537         }
 538         return (err);
 539 }
 540 
 541 void
 542 dmu_objset_rele(objset_t *os, void *tag)
 543 {
 544         dsl_pool_t *dp = dmu_objset_pool(os);
 545         dsl_dataset_rele(os->os_dsl_dataset, tag);
 546         dsl_pool_rele(dp, tag);
 547 }
 548 
 549 /*
 550  * When we are called, os MUST refer to an objset associated with a dataset
 551  * that is owned by 'tag'; that is, is held and long held by 'tag' and ds_owner
 552  * == tag.  We will then release and reacquire ownership of the dataset while
 553  * holding the pool config_rwlock to avoid intervening namespace or ownership
 554  * changes may occur.
 555  *
 556  * This exists solely to accommodate zfs_ioc_userspace_upgrade()'s desire to
 557  * release the hold on its dataset and acquire a new one on the dataset of the
 558  * same name so that it can be partially torn down and reconstructed.
 559  */
 560 void
 561 dmu_objset_refresh_ownership(objset_t *os, void *tag)
 562 {
 563         dsl_pool_t *dp;
 564         dsl_dataset_t *ds, *newds;
 565         char name[MAXNAMELEN];
 566 
 567         ds = os->os_dsl_dataset;
 568         VERIFY3P(ds, !=, NULL);
 569         VERIFY3P(ds->ds_owner, ==, tag);
 570         VERIFY(dsl_dataset_long_held(ds));
 571 
 572         dsl_dataset_name(ds, name);
 573         dp = dmu_objset_pool(os);
 574         dsl_pool_config_enter(dp, FTAG);
 575         dmu_objset_disown(os, tag);
 576         VERIFY0(dsl_dataset_own(dp, name, tag, &newds));
 577         VERIFY3P(newds, ==, os->os_dsl_dataset);
 578         dsl_pool_config_exit(dp, FTAG);
 579 }
 580 
 581 void
 582 dmu_objset_disown(objset_t *os, void *tag)
 583 {
 584         dsl_dataset_disown(os->os_dsl_dataset, tag);
 585 }
 586 
 587 void
 588 dmu_objset_evict_dbufs(objset_t *os)
 589 {
 590         dnode_t dn_marker;
 591         dnode_t *dn;
 592 
 593         mutex_enter(&os->os_lock);
 594         dn = list_head(&os->os_dnodes);
 595         while (dn != NULL) {
 596                 /*
 597                  * Skip dnodes without holds.  We have to do this dance
 598                  * because dnode_add_ref() only works if there is already a
 599                  * hold.  If the dnode has no holds, then it has no dbufs.
 600                  */
 601                 if (dnode_add_ref(dn, FTAG)) {
 602                         list_insert_after(&os->os_dnodes, dn, &dn_marker);
 603                         mutex_exit(&os->os_lock);
 604 
 605                         dnode_evict_dbufs(dn);
 606                         dnode_rele(dn, FTAG);
 607 
 608                         mutex_enter(&os->os_lock);
 609                         dn = list_next(&os->os_dnodes, &dn_marker);
 610                         list_remove(&os->os_dnodes, &dn_marker);
 611                 } else {
 612                         dn = list_next(&os->os_dnodes, dn);
 613                 }
 614         }
 615         mutex_exit(&os->os_lock);
 616 
 617         if (DMU_USERUSED_DNODE(os) != NULL) {
 618                 dnode_evict_dbufs(DMU_GROUPUSED_DNODE(os));
 619                 dnode_evict_dbufs(DMU_USERUSED_DNODE(os));
 620         }
 621         dnode_evict_dbufs(DMU_META_DNODE(os));
 622 }
 623 
 624 /*
 625  * Objset eviction processing is split into into two pieces.
 626  * The first marks the objset as evicting, evicts any dbufs that
 627  * have a refcount of zero, and then queues up the objset for the
 628  * second phase of eviction.  Once os->os_dnodes has been cleared by
 629  * dnode_buf_pageout()->dnode_destroy(), the second phase is executed.
 630  * The second phase closes the special dnodes, dequeues the objset from
 631  * the list of those undergoing eviction, and finally frees the objset.
 632  *
 633  * NOTE: Due to asynchronous eviction processing (invocation of
 634  *       dnode_buf_pageout()), it is possible for the meta dnode for the
 635  *       objset to have no holds even though os->os_dnodes is not empty.
 636  */
 637 void
 638 dmu_objset_evict(objset_t *os)
 639 {
 640         dsl_dataset_t *ds = os->os_dsl_dataset;
 641 
 642         for (int t = 0; t < TXG_SIZE; t++)
 643                 ASSERT(!dmu_objset_is_dirty(os, t));
 644 
 645         if (ds) {
 646                 if (!ds->ds_is_snapshot) {
 647                         VERIFY0(dsl_prop_unregister(ds,
 648                             zfs_prop_to_name(ZFS_PROP_CHECKSUM),
 649                             checksum_changed_cb, os));
 650                         VERIFY0(dsl_prop_unregister(ds,
 651                             zfs_prop_to_name(ZFS_PROP_COMPRESSION),
 652                             compression_changed_cb, os));
 653                         VERIFY0(dsl_prop_unregister(ds,
 654                             zfs_prop_to_name(ZFS_PROP_COPIES),
 655                             copies_changed_cb, os));
 656                         VERIFY0(dsl_prop_unregister(ds,
 657                             zfs_prop_to_name(ZFS_PROP_DEDUP),
 658                             dedup_changed_cb, os));
 659                         VERIFY0(dsl_prop_unregister(ds,
 660                             zfs_prop_to_name(ZFS_PROP_LOGBIAS),
 661                             logbias_changed_cb, os));
 662                         VERIFY0(dsl_prop_unregister(ds,
 663                             zfs_prop_to_name(ZFS_PROP_SYNC),
 664                             sync_changed_cb, os));
 665                         VERIFY0(dsl_prop_unregister(ds,
 666                             zfs_prop_to_name(ZFS_PROP_REDUNDANT_METADATA),
 667                             redundant_metadata_changed_cb, os));
 668                         VERIFY0(dsl_prop_unregister(ds,
 669                             zfs_prop_to_name(ZFS_PROP_RECORDSIZE),
 670                             recordsize_changed_cb, os));
 671                 }
 672                 VERIFY0(dsl_prop_unregister(ds,
 673                     zfs_prop_to_name(ZFS_PROP_PRIMARYCACHE),
 674                     primary_cache_changed_cb, os));
 675                 VERIFY0(dsl_prop_unregister(ds,
 676                     zfs_prop_to_name(ZFS_PROP_SECONDARYCACHE),
 677                     secondary_cache_changed_cb, os));
 678         }
 679 
 680         if (os->os_sa)
 681                 sa_tear_down(os);
 682 
 683         os->os_evicting = B_TRUE;
 684         dmu_objset_evict_dbufs(os);
 685 
 686         mutex_enter(&os->os_lock);
 687         spa_evicting_os_register(os->os_spa, os);
 688         if (list_is_empty(&os->os_dnodes)) {
 689                 mutex_exit(&os->os_lock);
 690                 dmu_objset_evict_done(os);
 691         } else {
 692                 mutex_exit(&os->os_lock);
 693         }
 694 }
 695 
 696 void
 697 dmu_objset_evict_done(objset_t *os)
 698 {
 699         ASSERT3P(list_head(&os->os_dnodes), ==, NULL);
 700 
 701         dnode_special_close(&os->os_meta_dnode);
 702         if (DMU_USERUSED_DNODE(os)) {
 703                 dnode_special_close(&os->os_userused_dnode);
 704                 dnode_special_close(&os->os_groupused_dnode);
 705         }
 706         zil_free(os->os_zil);
 707 
 708         VERIFY(arc_buf_remove_ref(os->os_phys_buf, &os->os_phys_buf));
 709 
 710         /*
 711          * This is a barrier to prevent the objset from going away in
 712          * dnode_move() until we can safely ensure that the objset is still in
 713          * use. We consider the objset valid before the barrier and invalid
 714          * after the barrier.
 715          */
 716         rw_enter(&os_lock, RW_READER);
 717         rw_exit(&os_lock);
 718 
 719         mutex_destroy(&os->os_lock);
 720         mutex_destroy(&os->os_obj_lock);
 721         mutex_destroy(&os->os_user_ptr_lock);
 722         spa_evicting_os_deregister(os->os_spa, os);
 723         kmem_free(os, sizeof (objset_t));
 724 }
 725 
 726 timestruc_t
 727 dmu_objset_snap_cmtime(objset_t *os)
 728 {
 729         return (dsl_dir_snap_cmtime(os->os_dsl_dataset->ds_dir));
 730 }
 731 
 732 /* called from dsl for meta-objset */
 733 objset_t *
 734 dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 735     dmu_objset_type_t type, dmu_tx_t *tx)
 736 {
 737         objset_t *os;
 738         dnode_t *mdn;
 739 
 740         ASSERT(dmu_tx_is_syncing(tx));
 741 
 742         if (ds != NULL)
 743                 VERIFY0(dmu_objset_from_ds(ds, &os));
 744         else
 745                 VERIFY0(dmu_objset_open_impl(spa, NULL, bp, &os));
 746 
 747         mdn = DMU_META_DNODE(os);
 748 
 749         dnode_allocate(mdn, DMU_OT_DNODE, 1 << DNODE_BLOCK_SHIFT,
 750             DN_MAX_INDBLKSHIFT, DMU_OT_NONE, 0, tx);
 751 
 752         /*
 753          * We don't want to have to increase the meta-dnode's nlevels
 754          * later, because then we could do it in quescing context while
 755          * we are also accessing it in open context.
 756          *
 757          * This precaution is not necessary for the MOS (ds == NULL),
 758          * because the MOS is only updated in syncing context.
 759          * This is most fortunate: the MOS is the only objset that
 760          * needs to be synced multiple times as spa_sync() iterates
 761          * to convergence, so minimizing its dn_nlevels matters.
 762          */
 763         if (ds != NULL) {
 764                 int levels = 1;
 765 
 766                 /*
 767                  * Determine the number of levels necessary for the meta-dnode
 768                  * to contain DN_MAX_OBJECT dnodes.
 769                  */
 770                 while ((uint64_t)mdn->dn_nblkptr << (mdn->dn_datablkshift +
 771                     (levels - 1) * (mdn->dn_indblkshift - SPA_BLKPTRSHIFT)) <
 772                     DN_MAX_OBJECT * sizeof (dnode_phys_t))
 773                         levels++;
 774 
 775                 mdn->dn_next_nlevels[tx->tx_txg & TXG_MASK] =
 776                     mdn->dn_nlevels = levels;
 777         }
 778 
 779         ASSERT(type != DMU_OST_NONE);
 780         ASSERT(type != DMU_OST_ANY);
 781         ASSERT(type < DMU_OST_NUMTYPES);
 782         os->os_phys->os_type = type;
 783         if (dmu_objset_userused_enabled(os)) {
 784                 os->os_phys->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
 785                 os->os_flags = os->os_phys->os_flags;
 786         }
 787 
 788         dsl_dataset_dirty(ds, tx);
 789 
 790         return (os);
 791 }
 792 
 793 typedef struct dmu_objset_create_arg {
 794         const char *doca_name;
 795         cred_t *doca_cred;
 796         void (*doca_userfunc)(objset_t *os, void *arg,
 797             cred_t *cr, dmu_tx_t *tx);
 798         void *doca_userarg;
 799         dmu_objset_type_t doca_type;
 800         uint64_t doca_flags;
 801 } dmu_objset_create_arg_t;
 802 
 803 /*ARGSUSED*/
 804 static int
 805 dmu_objset_create_check(void *arg, dmu_tx_t *tx)
 806 {
 807         dmu_objset_create_arg_t *doca = arg;
 808         dsl_pool_t *dp = dmu_tx_pool(tx);
 809         dsl_dir_t *pdd;
 810         const char *tail;
 811         int error;
 812 
 813         if (strchr(doca->doca_name, '@') != NULL)
 814                 return (SET_ERROR(EINVAL));
 815 
 816         error = dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail);
 817         if (error != 0)
 818                 return (error);
 819         if (tail == NULL) {
 820                 dsl_dir_rele(pdd, FTAG);
 821                 return (SET_ERROR(EEXIST));
 822         }
 823         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 824             doca->doca_cred);
 825         dsl_dir_rele(pdd, FTAG);
 826 
 827         return (error);
 828 }
 829 
 830 static void
 831 dmu_objset_create_sync(void *arg, dmu_tx_t *tx)
 832 {
 833         dmu_objset_create_arg_t *doca = arg;
 834         dsl_pool_t *dp = dmu_tx_pool(tx);
 835         dsl_dir_t *pdd;
 836         const char *tail;
 837         dsl_dataset_t *ds;
 838         uint64_t obj;
 839         blkptr_t *bp;
 840         objset_t *os;
 841 
 842         VERIFY0(dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail));
 843 
 844         obj = dsl_dataset_create_sync(pdd, tail, NULL, doca->doca_flags,
 845             doca->doca_cred, tx);
 846 
 847         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 848         bp = dsl_dataset_get_blkptr(ds);
 849         os = dmu_objset_create_impl(pdd->dd_pool->dp_spa,
 850             ds, bp, doca->doca_type, tx);
 851 
 852         if (doca->doca_userfunc != NULL) {
 853                 doca->doca_userfunc(os, doca->doca_userarg,
 854                     doca->doca_cred, tx);
 855         }
 856 
 857         spa_history_log_internal_ds(ds, "create", tx, "");
 858         dsl_dataset_rele(ds, FTAG);
 859         dsl_dir_rele(pdd, FTAG);
 860 }
 861 
 862 int
 863 dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
 864     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg)
 865 {
 866         dmu_objset_create_arg_t doca;
 867 
 868         doca.doca_name = name;
 869         doca.doca_cred = CRED();
 870         doca.doca_flags = flags;
 871         doca.doca_userfunc = func;
 872         doca.doca_userarg = arg;
 873         doca.doca_type = type;
 874 
 875         return (dsl_sync_task(name,
 876             dmu_objset_create_check, dmu_objset_create_sync, &doca,
 877             5, ZFS_SPACE_CHECK_NORMAL));
 878 }
 879 
 880 typedef struct dmu_objset_clone_arg {
 881         const char *doca_clone;
 882         const char *doca_origin;
 883         cred_t *doca_cred;
 884 } dmu_objset_clone_arg_t;
 885 
 886 /*ARGSUSED*/
 887 static int
 888 dmu_objset_clone_check(void *arg, dmu_tx_t *tx)
 889 {
 890         dmu_objset_clone_arg_t *doca = arg;
 891         dsl_dir_t *pdd;
 892         const char *tail;
 893         int error;
 894         dsl_dataset_t *origin;
 895         dsl_pool_t *dp = dmu_tx_pool(tx);
 896 
 897         if (strchr(doca->doca_clone, '@') != NULL)
 898                 return (SET_ERROR(EINVAL));
 899 
 900         error = dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail);
 901         if (error != 0)
 902                 return (error);
 903         if (tail == NULL) {
 904                 dsl_dir_rele(pdd, FTAG);
 905                 return (SET_ERROR(EEXIST));
 906         }
 907         /* You can't clone across pools. */
 908         if (pdd->dd_pool != dp) {
 909                 dsl_dir_rele(pdd, FTAG);
 910                 return (SET_ERROR(EXDEV));
 911         }
 912         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 913             doca->doca_cred);
 914         if (error != 0) {
 915                 dsl_dir_rele(pdd, FTAG);
 916                 return (SET_ERROR(EDQUOT));
 917         }
 918         dsl_dir_rele(pdd, FTAG);
 919 
 920         error = dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin);
 921         if (error != 0)
 922                 return (error);
 923 
 924         /* You can't clone across pools. */
 925         if (origin->ds_dir->dd_pool != dp) {
 926                 dsl_dataset_rele(origin, FTAG);
 927                 return (SET_ERROR(EXDEV));
 928         }
 929 
 930         /* You can only clone snapshots, not the head datasets. */
 931         if (!origin->ds_is_snapshot) {
 932                 dsl_dataset_rele(origin, FTAG);
 933                 return (SET_ERROR(EINVAL));
 934         }
 935         dsl_dataset_rele(origin, FTAG);
 936 
 937         return (0);
 938 }
 939 
 940 static void
 941 dmu_objset_clone_sync(void *arg, dmu_tx_t *tx)
 942 {
 943         dmu_objset_clone_arg_t *doca = arg;
 944         dsl_pool_t *dp = dmu_tx_pool(tx);
 945         dsl_dir_t *pdd;
 946         const char *tail;
 947         dsl_dataset_t *origin, *ds;
 948         uint64_t obj;
 949         char namebuf[MAXNAMELEN];
 950 
 951         VERIFY0(dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail));
 952         VERIFY0(dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin));
 953 
 954         obj = dsl_dataset_create_sync(pdd, tail, origin, 0,
 955             doca->doca_cred, tx);
 956 
 957         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 958         dsl_dataset_name(origin, namebuf);
 959         spa_history_log_internal_ds(ds, "clone", tx,
 960             "origin=%s (%llu)", namebuf, origin->ds_object);
 961         dsl_dataset_rele(ds, FTAG);
 962         dsl_dataset_rele(origin, FTAG);
 963         dsl_dir_rele(pdd, FTAG);
 964 }
 965 
 966 int
 967 dmu_objset_clone(const char *clone, const char *origin)
 968 {
 969         dmu_objset_clone_arg_t doca;
 970 
 971         doca.doca_clone = clone;
 972         doca.doca_origin = origin;
 973         doca.doca_cred = CRED();
 974 
 975         return (dsl_sync_task(clone,
 976             dmu_objset_clone_check, dmu_objset_clone_sync, &doca,
 977             5, ZFS_SPACE_CHECK_NORMAL));
 978 }
 979 
 980 int
 981 dmu_objset_snapshot_one(const char *fsname, const char *snapname)
 982 {
 983         int err;
 984         char *longsnap = kmem_asprintf("%s@%s", fsname, snapname);
 985         nvlist_t *snaps = fnvlist_alloc();
 986 
 987         fnvlist_add_boolean(snaps, longsnap);
 988         strfree(longsnap);
 989         err = dsl_dataset_snapshot(snaps, NULL, NULL);
 990         fnvlist_free(snaps);
 991         return (err);
 992 }
 993 
 994 static void
 995 dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
 996 {
 997         dnode_t *dn;
 998 
 999         while (dn = list_head(list)) {
1000                 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
1001                 ASSERT(dn->dn_dbuf->db_data_pending);
1002                 /*
1003                  * Initialize dn_zio outside dnode_sync() because the
1004                  * meta-dnode needs to set it ouside dnode_sync().
1005                  */
1006                 dn->dn_zio = dn->dn_dbuf->db_data_pending->dr_zio;
1007                 ASSERT(dn->dn_zio);
1008 
1009                 ASSERT3U(dn->dn_nlevels, <=, DN_MAX_LEVELS);
1010                 list_remove(list, dn);
1011 
1012                 if (newlist) {
1013                         (void) dnode_add_ref(dn, newlist);
1014                         list_insert_tail(newlist, dn);
1015                 }
1016 
1017                 dnode_sync(dn, tx);
1018         }
1019 }
1020 
1021 /* ARGSUSED */
1022 static void
1023 dmu_objset_write_ready(zio_t *zio, arc_buf_t *abuf, void *arg)
1024 {
1025         blkptr_t *bp = zio->io_bp;
1026         objset_t *os = arg;
1027         dnode_phys_t *dnp = &os->os_phys->os_meta_dnode;
1028 
1029         ASSERT(!BP_IS_EMBEDDED(bp));
1030         ASSERT3P(bp, ==, os->os_rootbp);
1031         ASSERT3U(BP_GET_TYPE(bp), ==, DMU_OT_OBJSET);
1032         ASSERT0(BP_GET_LEVEL(bp));
1033 
1034         /*
1035          * Update rootbp fill count: it should be the number of objects
1036          * allocated in the object set (not counting the "special"
1037          * objects that are stored in the objset_phys_t -- the meta
1038          * dnode and user/group accounting objects).
1039          */
1040         bp->blk_fill = 0;
1041         for (int i = 0; i < dnp->dn_nblkptr; i++)
1042                 bp->blk_fill += BP_GET_FILL(&dnp->dn_blkptr[i]);
1043 }
1044 
1045 /* ARGSUSED */
1046 static void
1047 dmu_objset_write_done(zio_t *zio, arc_buf_t *abuf, void *arg)
1048 {
1049         blkptr_t *bp = zio->io_bp;
1050         blkptr_t *bp_orig = &zio->io_bp_orig;
1051         objset_t *os = arg;
1052 
1053         if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
1054                 ASSERT(BP_EQUAL(bp, bp_orig));
1055         } else {
1056                 dsl_dataset_t *ds = os->os_dsl_dataset;
1057                 dmu_tx_t *tx = os->os_synctx;
1058 
1059                 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
1060                 dsl_dataset_block_born(ds, bp, tx);
1061         }
1062 }
1063 
1064 /* called from dsl */
1065 void
1066 dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
1067 {
1068         int txgoff;
1069         zbookmark_phys_t zb;
1070         zio_prop_t zp;
1071         zio_t *zio;
1072         list_t *list;
1073         list_t *newlist = NULL;
1074         dbuf_dirty_record_t *dr;
1075 
1076         dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
1077 
1078         ASSERT(dmu_tx_is_syncing(tx));
1079         /* XXX the write_done callback should really give us the tx... */
1080         os->os_synctx = tx;
1081 
1082         if (os->os_dsl_dataset == NULL) {
1083                 /*
1084                  * This is the MOS.  If we have upgraded,
1085                  * spa_max_replication() could change, so reset
1086                  * os_copies here.
1087                  */
1088                 os->os_copies = spa_max_replication(os->os_spa);
1089         }
1090 
1091         /*
1092          * Create the root block IO
1093          */
1094         SET_BOOKMARK(&zb, os->os_dsl_dataset ?
1095             os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
1096             ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
1097         arc_release(os->os_phys_buf, &os->os_phys_buf);
1098 
1099         dmu_write_policy(os, NULL, 0, 0, &zp);
1100 
1101         zio = arc_write(pio, os->os_spa, tx->tx_txg,
1102             os->os_rootbp, os->os_phys_buf, DMU_OS_IS_L2CACHEABLE(os),
1103             DMU_OS_IS_L2COMPRESSIBLE(os), &zp, dmu_objset_write_ready,
1104             NULL, dmu_objset_write_done, os, ZIO_PRIORITY_ASYNC_WRITE,
1105             ZIO_FLAG_MUSTSUCCEED, &zb);
1106 
1107         /*
1108          * Sync special dnodes - the parent IO for the sync is the root block
1109          */
1110         DMU_META_DNODE(os)->dn_zio = zio;
1111         dnode_sync(DMU_META_DNODE(os), tx);
1112 
1113         os->os_phys->os_flags = os->os_flags;
1114 
1115         if (DMU_USERUSED_DNODE(os) &&
1116             DMU_USERUSED_DNODE(os)->dn_type != DMU_OT_NONE) {
1117                 DMU_USERUSED_DNODE(os)->dn_zio = zio;
1118                 dnode_sync(DMU_USERUSED_DNODE(os), tx);
1119                 DMU_GROUPUSED_DNODE(os)->dn_zio = zio;
1120                 dnode_sync(DMU_GROUPUSED_DNODE(os), tx);
1121         }
1122 
1123         txgoff = tx->tx_txg & TXG_MASK;
1124 
1125         if (dmu_objset_userused_enabled(os)) {
1126                 newlist = &os->os_synced_dnodes;
1127                 /*
1128                  * We must create the list here because it uses the
1129                  * dn_dirty_link[] of this txg.
1130                  */
1131                 list_create(newlist, sizeof (dnode_t),
1132                     offsetof(dnode_t, dn_dirty_link[txgoff]));
1133         }
1134 
1135         dmu_objset_sync_dnodes(&os->os_free_dnodes[txgoff], newlist, tx);
1136         dmu_objset_sync_dnodes(&os->os_dirty_dnodes[txgoff], newlist, tx);
1137 
1138         list = &DMU_META_DNODE(os)->dn_dirty_records[txgoff];
1139         while (dr = list_head(list)) {
1140                 ASSERT0(dr->dr_dbuf->db_level);
1141                 list_remove(list, dr);
1142                 if (dr->dr_zio)
1143                         zio_nowait(dr->dr_zio);
1144         }
1145         /*
1146          * Free intent log blocks up to this tx.
1147          */
1148         zil_sync(os->os_zil, tx);
1149         os->os_phys->os_zil_header = os->os_zil_header;
1150         zio_nowait(zio);
1151 }
1152 
1153 boolean_t
1154 dmu_objset_is_dirty(objset_t *os, uint64_t txg)
1155 {
1156         return (!list_is_empty(&os->os_dirty_dnodes[txg & TXG_MASK]) ||
1157             !list_is_empty(&os->os_free_dnodes[txg & TXG_MASK]));
1158 }
1159 
1160 static objset_used_cb_t *used_cbs[DMU_OST_NUMTYPES];
1161 
1162 void
1163 dmu_objset_register_type(dmu_objset_type_t ost, objset_used_cb_t *cb)
1164 {
1165         used_cbs[ost] = cb;
1166 }
1167 
1168 boolean_t
1169 dmu_objset_userused_enabled(objset_t *os)
1170 {
1171         return (spa_version(os->os_spa) >= SPA_VERSION_USERSPACE &&
1172             used_cbs[os->os_phys->os_type] != NULL &&
1173             DMU_USERUSED_DNODE(os) != NULL);
1174 }
1175 
1176 static void
1177 do_userquota_update(objset_t *os, uint64_t used, uint64_t flags,
1178     uint64_t user, uint64_t group, boolean_t subtract, dmu_tx_t *tx)
1179 {
1180         if ((flags & DNODE_FLAG_USERUSED_ACCOUNTED)) {
1181                 int64_t delta = DNODE_SIZE + used;
1182                 if (subtract)
1183                         delta = -delta;
1184                 VERIFY3U(0, ==, zap_increment_int(os, DMU_USERUSED_OBJECT,
1185                     user, delta, tx));
1186                 VERIFY3U(0, ==, zap_increment_int(os, DMU_GROUPUSED_OBJECT,
1187                     group, delta, tx));
1188         }
1189 }
1190 
1191 void
1192 dmu_objset_do_userquota_updates(objset_t *os, dmu_tx_t *tx)
1193 {
1194         dnode_t *dn;
1195         list_t *list = &os->os_synced_dnodes;
1196 
1197         ASSERT(list_head(list) == NULL || dmu_objset_userused_enabled(os));
1198 
1199         while (dn = list_head(list)) {
1200                 int flags;
1201                 ASSERT(!DMU_OBJECT_IS_SPECIAL(dn->dn_object));
1202                 ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE ||
1203                     dn->dn_phys->dn_flags &
1204                     DNODE_FLAG_USERUSED_ACCOUNTED);
1205 
1206                 /* Allocate the user/groupused objects if necessary. */
1207                 if (DMU_USERUSED_DNODE(os)->dn_type == DMU_OT_NONE) {
1208                         VERIFY(0 == zap_create_claim(os,
1209                             DMU_USERUSED_OBJECT,
1210                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1211                         VERIFY(0 == zap_create_claim(os,
1212                             DMU_GROUPUSED_OBJECT,
1213                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1214                 }
1215 
1216                 /*
1217                  * We intentionally modify the zap object even if the
1218                  * net delta is zero.  Otherwise
1219                  * the block of the zap obj could be shared between
1220                  * datasets but need to be different between them after
1221                  * a bprewrite.
1222                  */
1223 
1224                 flags = dn->dn_id_flags;
1225                 ASSERT(flags);
1226                 if (flags & DN_ID_OLD_EXIST)  {
1227                         do_userquota_update(os, dn->dn_oldused, dn->dn_oldflags,
1228                             dn->dn_olduid, dn->dn_oldgid, B_TRUE, tx);
1229                 }
1230                 if (flags & DN_ID_NEW_EXIST) {
1231                         do_userquota_update(os, DN_USED_BYTES(dn->dn_phys),
1232                             dn->dn_phys->dn_flags,  dn->dn_newuid,
1233                             dn->dn_newgid, B_FALSE, tx);
1234                 }
1235 
1236                 mutex_enter(&dn->dn_mtx);
1237                 dn->dn_oldused = 0;
1238                 dn->dn_oldflags = 0;
1239                 if (dn->dn_id_flags & DN_ID_NEW_EXIST) {
1240                         dn->dn_olduid = dn->dn_newuid;
1241                         dn->dn_oldgid = dn->dn_newgid;
1242                         dn->dn_id_flags |= DN_ID_OLD_EXIST;
1243                         if (dn->dn_bonuslen == 0)
1244                                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1245                         else
1246                                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1247                 }
1248                 dn->dn_id_flags &= ~(DN_ID_NEW_EXIST);
1249                 mutex_exit(&dn->dn_mtx);
1250 
1251                 list_remove(list, dn);
1252                 dnode_rele(dn, list);
1253         }
1254 }
1255 
1256 /*
1257  * Returns a pointer to data to find uid/gid from
1258  *
1259  * If a dirty record for transaction group that is syncing can't
1260  * be found then NULL is returned.  In the NULL case it is assumed
1261  * the uid/gid aren't changing.
1262  */
1263 static void *
1264 dmu_objset_userquota_find_data(dmu_buf_impl_t *db, dmu_tx_t *tx)
1265 {
1266         dbuf_dirty_record_t *dr, **drp;
1267         void *data;
1268 
1269         if (db->db_dirtycnt == 0)
1270                 return (db->db.db_data);  /* Nothing is changing */
1271 
1272         for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1273                 if (dr->dr_txg == tx->tx_txg)
1274                         break;
1275 
1276         if (dr == NULL) {
1277                 data = NULL;
1278         } else {
1279                 dnode_t *dn;
1280 
1281                 DB_DNODE_ENTER(dr->dr_dbuf);
1282                 dn = DB_DNODE(dr->dr_dbuf);
1283 
1284                 if (dn->dn_bonuslen == 0 &&
1285                     dr->dr_dbuf->db_blkid == DMU_SPILL_BLKID)
1286                         data = dr->dt.dl.dr_data->b_data;
1287                 else
1288                         data = dr->dt.dl.dr_data;
1289 
1290                 DB_DNODE_EXIT(dr->dr_dbuf);
1291         }
1292 
1293         return (data);
1294 }
1295 
1296 void
1297 dmu_objset_userquota_get_ids(dnode_t *dn, boolean_t before, dmu_tx_t *tx)
1298 {
1299         objset_t *os = dn->dn_objset;
1300         void *data = NULL;
1301         dmu_buf_impl_t *db = NULL;
1302         uint64_t *user = NULL;
1303         uint64_t *group = NULL;
1304         int flags = dn->dn_id_flags;
1305         int error;
1306         boolean_t have_spill = B_FALSE;
1307 
1308         if (!dmu_objset_userused_enabled(dn->dn_objset))
1309                 return;
1310 
1311         if (before && (flags & (DN_ID_CHKED_BONUS|DN_ID_OLD_EXIST|
1312             DN_ID_CHKED_SPILL)))
1313                 return;
1314 
1315         if (before && dn->dn_bonuslen != 0)
1316                 data = DN_BONUS(dn->dn_phys);
1317         else if (!before && dn->dn_bonuslen != 0) {
1318                 if (dn->dn_bonus) {
1319                         db = dn->dn_bonus;
1320                         mutex_enter(&db->db_mtx);
1321                         data = dmu_objset_userquota_find_data(db, tx);
1322                 } else {
1323                         data = DN_BONUS(dn->dn_phys);
1324                 }
1325         } else if (dn->dn_bonuslen == 0 && dn->dn_bonustype == DMU_OT_SA) {
1326                         int rf = 0;
1327 
1328                         if (RW_WRITE_HELD(&dn->dn_struct_rwlock))
1329                                 rf |= DB_RF_HAVESTRUCT;
1330                         error = dmu_spill_hold_by_dnode(dn,
1331                             rf | DB_RF_MUST_SUCCEED,
1332                             FTAG, (dmu_buf_t **)&db);
1333                         ASSERT(error == 0);
1334                         mutex_enter(&db->db_mtx);
1335                         data = (before) ? db->db.db_data :
1336                             dmu_objset_userquota_find_data(db, tx);
1337                         have_spill = B_TRUE;
1338         } else {
1339                 mutex_enter(&dn->dn_mtx);
1340                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1341                 mutex_exit(&dn->dn_mtx);
1342                 return;
1343         }
1344 
1345         if (before) {
1346                 ASSERT(data);
1347                 user = &dn->dn_olduid;
1348                 group = &dn->dn_oldgid;
1349         } else if (data) {
1350                 user = &dn->dn_newuid;
1351                 group = &dn->dn_newgid;
1352         }
1353 
1354         /*
1355          * Must always call the callback in case the object
1356          * type has changed and that type isn't an object type to track
1357          */
1358         error = used_cbs[os->os_phys->os_type](dn->dn_bonustype, data,
1359             user, group);
1360 
1361         /*
1362          * Preserve existing uid/gid when the callback can't determine
1363          * what the new uid/gid are and the callback returned EEXIST.
1364          * The EEXIST error tells us to just use the existing uid/gid.
1365          * If we don't know what the old values are then just assign
1366          * them to 0, since that is a new file  being created.
1367          */
1368         if (!before && data == NULL && error == EEXIST) {
1369                 if (flags & DN_ID_OLD_EXIST) {
1370                         dn->dn_newuid = dn->dn_olduid;
1371                         dn->dn_newgid = dn->dn_oldgid;
1372                 } else {
1373                         dn->dn_newuid = 0;
1374                         dn->dn_newgid = 0;
1375                 }
1376                 error = 0;
1377         }
1378 
1379         if (db)
1380                 mutex_exit(&db->db_mtx);
1381 
1382         mutex_enter(&dn->dn_mtx);
1383         if (error == 0 && before)
1384                 dn->dn_id_flags |= DN_ID_OLD_EXIST;
1385         if (error == 0 && !before)
1386                 dn->dn_id_flags |= DN_ID_NEW_EXIST;
1387 
1388         if (have_spill) {
1389                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1390         } else {
1391                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1392         }
1393         mutex_exit(&dn->dn_mtx);
1394         if (have_spill)
1395                 dmu_buf_rele((dmu_buf_t *)db, FTAG);
1396 }
1397 
1398 boolean_t
1399 dmu_objset_userspace_present(objset_t *os)
1400 {
1401         return (os->os_phys->os_flags &
1402             OBJSET_FLAG_USERACCOUNTING_COMPLETE);
1403 }
1404 
1405 int
1406 dmu_objset_userspace_upgrade(objset_t *os)
1407 {
1408         uint64_t obj;
1409         int err = 0;
1410 
1411         if (dmu_objset_userspace_present(os))
1412                 return (0);
1413         if (!dmu_objset_userused_enabled(os))
1414                 return (SET_ERROR(ENOTSUP));
1415         if (dmu_objset_is_snapshot(os))
1416                 return (SET_ERROR(EINVAL));
1417 
1418         /*
1419          * We simply need to mark every object dirty, so that it will be
1420          * synced out and now accounted.  If this is called
1421          * concurrently, or if we already did some work before crashing,
1422          * that's fine, since we track each object's accounted state
1423          * independently.
1424          */
1425 
1426         for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, 0)) {
1427                 dmu_tx_t *tx;
1428                 dmu_buf_t *db;
1429                 int objerr;
1430 
1431                 if (issig(JUSTLOOKING) && issig(FORREAL))
1432                         return (SET_ERROR(EINTR));
1433 
1434                 objerr = dmu_bonus_hold(os, obj, FTAG, &db);
1435                 if (objerr != 0)
1436                         continue;
1437                 tx = dmu_tx_create(os);
1438                 dmu_tx_hold_bonus(tx, obj);
1439                 objerr = dmu_tx_assign(tx, TXG_WAIT);
1440                 if (objerr != 0) {
1441                         dmu_tx_abort(tx);
1442                         continue;
1443                 }
1444                 dmu_buf_will_dirty(db, tx);
1445                 dmu_buf_rele(db, FTAG);
1446                 dmu_tx_commit(tx);
1447         }
1448 
1449         os->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
1450         txg_wait_synced(dmu_objset_pool(os), 0);
1451         return (0);
1452 }
1453 
1454 void
1455 dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
1456     uint64_t *usedobjsp, uint64_t *availobjsp)
1457 {
1458         dsl_dataset_space(os->os_dsl_dataset, refdbytesp, availbytesp,
1459             usedobjsp, availobjsp);
1460 }
1461 
1462 uint64_t
1463 dmu_objset_fsid_guid(objset_t *os)
1464 {
1465         return (dsl_dataset_fsid_guid(os->os_dsl_dataset));
1466 }
1467 
1468 void
1469 dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat)
1470 {
1471         stat->dds_type = os->os_phys->os_type;
1472         if (os->os_dsl_dataset)
1473                 dsl_dataset_fast_stat(os->os_dsl_dataset, stat);
1474 }
1475 
1476 void
1477 dmu_objset_stats(objset_t *os, nvlist_t *nv)
1478 {
1479         ASSERT(os->os_dsl_dataset ||
1480             os->os_phys->os_type == DMU_OST_META);
1481 
1482         if (os->os_dsl_dataset != NULL)
1483                 dsl_dataset_stats(os->os_dsl_dataset, nv);
1484 
1485         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_TYPE,
1486             os->os_phys->os_type);
1487         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERACCOUNTING,
1488             dmu_objset_userspace_present(os));
1489 }
1490 
1491 int
1492 dmu_objset_is_snapshot(objset_t *os)
1493 {
1494         if (os->os_dsl_dataset != NULL)
1495                 return (os->os_dsl_dataset->ds_is_snapshot);
1496         else
1497                 return (B_FALSE);
1498 }
1499 
1500 int
1501 dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen,
1502     boolean_t *conflict)
1503 {
1504         dsl_dataset_t *ds = os->os_dsl_dataset;
1505         uint64_t ignored;
1506 
1507         if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
1508                 return (SET_ERROR(ENOENT));
1509 
1510         return (zap_lookup_norm(ds->ds_dir->dd_pool->dp_meta_objset,
1511             dsl_dataset_phys(ds)->ds_snapnames_zapobj, name, 8, 1, &ignored,
1512             MT_FIRST, real, maxlen, conflict));
1513 }
1514 
1515 int
1516 dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
1517     uint64_t *idp, uint64_t *offp, boolean_t *case_conflict)
1518 {
1519         dsl_dataset_t *ds = os->os_dsl_dataset;
1520         zap_cursor_t cursor;
1521         zap_attribute_t attr;
1522 
1523         ASSERT(dsl_pool_config_held(dmu_objset_pool(os)));
1524 
1525         if (dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0)
1526                 return (SET_ERROR(ENOENT));
1527 
1528         zap_cursor_init_serialized(&cursor,
1529             ds->ds_dir->dd_pool->dp_meta_objset,
1530             dsl_dataset_phys(ds)->ds_snapnames_zapobj, *offp);
1531 
1532         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1533                 zap_cursor_fini(&cursor);
1534                 return (SET_ERROR(ENOENT));
1535         }
1536 
1537         if (strlen(attr.za_name) + 1 > namelen) {
1538                 zap_cursor_fini(&cursor);
1539                 return (SET_ERROR(ENAMETOOLONG));
1540         }
1541 
1542         (void) strcpy(name, attr.za_name);
1543         if (idp)
1544                 *idp = attr.za_first_integer;
1545         if (case_conflict)
1546                 *case_conflict = attr.za_normalization_conflict;
1547         zap_cursor_advance(&cursor);
1548         *offp = zap_cursor_serialize(&cursor);
1549         zap_cursor_fini(&cursor);
1550 
1551         return (0);
1552 }
1553 
1554 int
1555 dmu_dir_list_next(objset_t *os, int namelen, char *name,
1556     uint64_t *idp, uint64_t *offp)
1557 {
1558         dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
1559         zap_cursor_t cursor;
1560         zap_attribute_t attr;
1561 
1562         /* there is no next dir on a snapshot! */
1563         if (os->os_dsl_dataset->ds_object !=
1564             dsl_dir_phys(dd)->dd_head_dataset_obj)
1565                 return (SET_ERROR(ENOENT));
1566 
1567         zap_cursor_init_serialized(&cursor,
1568             dd->dd_pool->dp_meta_objset,
1569             dsl_dir_phys(dd)->dd_child_dir_zapobj, *offp);
1570 
1571         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1572                 zap_cursor_fini(&cursor);
1573                 return (SET_ERROR(ENOENT));
1574         }
1575 
1576         if (strlen(attr.za_name) + 1 > namelen) {
1577                 zap_cursor_fini(&cursor);
1578                 return (SET_ERROR(ENAMETOOLONG));
1579         }
1580 
1581         (void) strcpy(name, attr.za_name);
1582         if (idp)
1583                 *idp = attr.za_first_integer;
1584         zap_cursor_advance(&cursor);
1585         *offp = zap_cursor_serialize(&cursor);
1586         zap_cursor_fini(&cursor);
1587 
1588         return (0);
1589 }
1590 
1591 /*
1592  * Find objsets under and including ddobj, call func(ds) on each.
1593  */
1594 int
1595 dmu_objset_find_dp(dsl_pool_t *dp, uint64_t ddobj,
1596     int func(dsl_pool_t *, dsl_dataset_t *, void *), void *arg, int flags)
1597 {
1598         dsl_dir_t *dd;
1599         dsl_dataset_t *ds;
1600         zap_cursor_t zc;
1601         zap_attribute_t *attr;
1602         uint64_t thisobj;
1603         int err;
1604 
1605         ASSERT(dsl_pool_config_held(dp));
1606 
1607         err = dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd);
1608         if (err != 0)
1609                 return (err);
1610 
1611         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1612         if (dd->dd_myname[0] == '$') {
1613                 dsl_dir_rele(dd, FTAG);
1614                 return (0);
1615         }
1616 
1617         thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
1618         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1619 
1620         /*
1621          * Iterate over all children.
1622          */
1623         if (flags & DS_FIND_CHILDREN) {
1624                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1625                     dsl_dir_phys(dd)->dd_child_dir_zapobj);
1626                     zap_cursor_retrieve(&zc, attr) == 0;
1627                     (void) zap_cursor_advance(&zc)) {
1628                         ASSERT3U(attr->za_integer_length, ==,
1629                             sizeof (uint64_t));
1630                         ASSERT3U(attr->za_num_integers, ==, 1);
1631 
1632                         err = dmu_objset_find_dp(dp, attr->za_first_integer,
1633                             func, arg, flags);
1634                         if (err != 0)
1635                                 break;
1636                 }
1637                 zap_cursor_fini(&zc);
1638 
1639                 if (err != 0) {
1640                         dsl_dir_rele(dd, FTAG);
1641                         kmem_free(attr, sizeof (zap_attribute_t));
1642                         return (err);
1643                 }
1644         }
1645 
1646         /*
1647          * Iterate over all snapshots.
1648          */
1649         if (flags & DS_FIND_SNAPSHOTS) {
1650                 dsl_dataset_t *ds;
1651                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1652 
1653                 if (err == 0) {
1654                         uint64_t snapobj;
1655 
1656                         snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
1657                         dsl_dataset_rele(ds, FTAG);
1658 
1659                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1660                             zap_cursor_retrieve(&zc, attr) == 0;
1661                             (void) zap_cursor_advance(&zc)) {
1662                                 ASSERT3U(attr->za_integer_length, ==,
1663                                     sizeof (uint64_t));
1664                                 ASSERT3U(attr->za_num_integers, ==, 1);
1665 
1666                                 err = dsl_dataset_hold_obj(dp,
1667                                     attr->za_first_integer, FTAG, &ds);
1668                                 if (err != 0)
1669                                         break;
1670                                 err = func(dp, ds, arg);
1671                                 dsl_dataset_rele(ds, FTAG);
1672                                 if (err != 0)
1673                                         break;
1674                         }
1675                         zap_cursor_fini(&zc);
1676                 }
1677         }
1678 
1679         dsl_dir_rele(dd, FTAG);
1680         kmem_free(attr, sizeof (zap_attribute_t));
1681 
1682         if (err != 0)
1683                 return (err);
1684 
1685         /*
1686          * Apply to self.
1687          */
1688         err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1689         if (err != 0)
1690                 return (err);
1691         err = func(dp, ds, arg);
1692         dsl_dataset_rele(ds, FTAG);
1693         return (err);
1694 }
1695 
1696 /*
1697  * Find all objsets under name, and for each, call 'func(child_name, arg)'.
1698  * The dp_config_rwlock must not be held when this is called, and it
1699  * will not be held when the callback is called.
1700  * Therefore this function should only be used when the pool is not changing
1701  * (e.g. in syncing context), or the callback can deal with the possible races.
1702  */
1703 static int
1704 dmu_objset_find_impl(spa_t *spa, const char *name,
1705     int func(const char *, void *), void *arg, int flags)
1706 {
1707         dsl_dir_t *dd;
1708         dsl_pool_t *dp = spa_get_dsl(spa);
1709         dsl_dataset_t *ds;
1710         zap_cursor_t zc;
1711         zap_attribute_t *attr;
1712         char *child;
1713         uint64_t thisobj;
1714         int err;
1715 
1716         dsl_pool_config_enter(dp, FTAG);
1717 
1718         err = dsl_dir_hold(dp, name, FTAG, &dd, NULL);
1719         if (err != 0) {
1720                 dsl_pool_config_exit(dp, FTAG);
1721                 return (err);
1722         }
1723 
1724         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1725         if (dd->dd_myname[0] == '$') {
1726                 dsl_dir_rele(dd, FTAG);
1727                 dsl_pool_config_exit(dp, FTAG);
1728                 return (0);
1729         }
1730 
1731         thisobj = dsl_dir_phys(dd)->dd_head_dataset_obj;
1732         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1733 
1734         /*
1735          * Iterate over all children.
1736          */
1737         if (flags & DS_FIND_CHILDREN) {
1738                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1739                     dsl_dir_phys(dd)->dd_child_dir_zapobj);
1740                     zap_cursor_retrieve(&zc, attr) == 0;
1741                     (void) zap_cursor_advance(&zc)) {
1742                         ASSERT3U(attr->za_integer_length, ==,
1743                             sizeof (uint64_t));
1744                         ASSERT3U(attr->za_num_integers, ==, 1);
1745 
1746                         child = kmem_asprintf("%s/%s", name, attr->za_name);
1747                         dsl_pool_config_exit(dp, FTAG);
1748                         err = dmu_objset_find_impl(spa, child,
1749                             func, arg, flags);
1750                         dsl_pool_config_enter(dp, FTAG);
1751                         strfree(child);
1752                         if (err != 0)
1753                                 break;
1754                 }
1755                 zap_cursor_fini(&zc);
1756 
1757                 if (err != 0) {
1758                         dsl_dir_rele(dd, FTAG);
1759                         dsl_pool_config_exit(dp, FTAG);
1760                         kmem_free(attr, sizeof (zap_attribute_t));
1761                         return (err);
1762                 }
1763         }
1764 
1765         /*
1766          * Iterate over all snapshots.
1767          */
1768         if (flags & DS_FIND_SNAPSHOTS) {
1769                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1770 
1771                 if (err == 0) {
1772                         uint64_t snapobj;
1773 
1774                         snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
1775                         dsl_dataset_rele(ds, FTAG);
1776 
1777                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1778                             zap_cursor_retrieve(&zc, attr) == 0;
1779                             (void) zap_cursor_advance(&zc)) {
1780                                 ASSERT3U(attr->za_integer_length, ==,
1781                                     sizeof (uint64_t));
1782                                 ASSERT3U(attr->za_num_integers, ==, 1);
1783 
1784                                 child = kmem_asprintf("%s@%s",
1785                                     name, attr->za_name);
1786                                 dsl_pool_config_exit(dp, FTAG);
1787                                 err = func(child, arg);
1788                                 dsl_pool_config_enter(dp, FTAG);
1789                                 strfree(child);
1790                                 if (err != 0)
1791                                         break;
1792                         }
1793                         zap_cursor_fini(&zc);
1794                 }
1795         }
1796 
1797         dsl_dir_rele(dd, FTAG);
1798         kmem_free(attr, sizeof (zap_attribute_t));
1799         dsl_pool_config_exit(dp, FTAG);
1800 
1801         if (err != 0)
1802                 return (err);
1803 
1804         /* Apply to self. */
1805         return (func(name, arg));
1806 }
1807 
1808 /*
1809  * See comment above dmu_objset_find_impl().
1810  */
1811 int
1812 dmu_objset_find(char *name, int func(const char *, void *), void *arg,
1813     int flags)
1814 {
1815         spa_t *spa;
1816         int error;
1817 
1818         error = spa_open(name, &spa, FTAG);
1819         if (error != 0)
1820                 return (error);
1821         error = dmu_objset_find_impl(spa, name, func, arg, flags);
1822         spa_close(spa, FTAG);
1823         return (error);
1824 }
1825 
1826 void
1827 dmu_objset_set_user(objset_t *os, void *user_ptr)
1828 {
1829         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1830         os->os_user_ptr = user_ptr;
1831 }
1832 
1833 void *
1834 dmu_objset_get_user(objset_t *os)
1835 {
1836         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1837         return (os->os_user_ptr);
1838 }
1839 
1840 /*
1841  * Determine name of filesystem, given name of snapshot.
1842  * buf must be at least MAXNAMELEN bytes
1843  */
1844 int
1845 dmu_fsname(const char *snapname, char *buf)
1846 {
1847         char *atp = strchr(snapname, '@');
1848         if (atp == NULL)
1849                 return (SET_ERROR(EINVAL));
1850         if (atp - snapname >= MAXNAMELEN)
1851                 return (SET_ERROR(ENAMETOOLONG));
1852         (void) strlcpy(buf, snapname, atp - snapname + 1);
1853         return (0);
1854 }