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  */
  27 
  28 /* Portions Copyright 2010 Robert Milkowski */
  29 
  30 #include <sys/cred.h>
  31 #include <sys/zfs_context.h>
  32 #include <sys/dmu_objset.h>
  33 #include <sys/dsl_dir.h>
  34 #include <sys/dsl_dataset.h>
  35 #include <sys/dsl_prop.h>
  36 #include <sys/dsl_pool.h>
  37 #include <sys/dsl_synctask.h>
  38 #include <sys/dsl_deleg.h>
  39 #include <sys/dnode.h>
  40 #include <sys/dbuf.h>
  41 #include <sys/zvol.h>
  42 #include <sys/dmu_tx.h>
  43 #include <sys/zap.h>
  44 #include <sys/zil.h>
  45 #include <sys/dmu_impl.h>
  46 #include <sys/zfs_ioctl.h>
  47 #include <sys/sa.h>
  48 #include <sys/zfs_onexit.h>
  49 #include <sys/dsl_destroy.h>
  50 #include <sys/vdev.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 void
 260 dmu_objset_byteswap(void *buf, size_t size)
 261 {
 262         objset_phys_t *osp = buf;
 263 
 264         ASSERT(size == OBJSET_OLD_PHYS_SIZE || size == sizeof (objset_phys_t));
 265         dnode_byteswap(&osp->os_meta_dnode);
 266         byteswap_uint64_array(&osp->os_zil_header, sizeof (zil_header_t));
 267         osp->os_type = BSWAP_64(osp->os_type);
 268         osp->os_flags = BSWAP_64(osp->os_flags);
 269         if (size == sizeof (objset_phys_t)) {
 270                 dnode_byteswap(&osp->os_userused_dnode);
 271                 dnode_byteswap(&osp->os_groupused_dnode);
 272         }
 273 }
 274 
 275 int
 276 dmu_objset_open_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 277     objset_t **osp)
 278 {
 279         objset_t *os;
 280         int i, err;
 281 
 282         ASSERT(ds == NULL || MUTEX_HELD(&ds->ds_opening_lock));
 283 
 284         os = kmem_zalloc(sizeof (objset_t), KM_SLEEP);
 285         os->os_dsl_dataset = ds;
 286         os->os_spa = spa;
 287         os->os_rootbp = bp;
 288         if (!BP_IS_HOLE(os->os_rootbp)) {
 289                 uint32_t aflags = ARC_WAIT;
 290                 zbookmark_t zb;
 291                 SET_BOOKMARK(&zb, ds ? ds->ds_object : DMU_META_OBJSET,
 292                     ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
 293 
 294                 if (DMU_OS_IS_L2CACHEABLE(os))
 295                         aflags |= ARC_L2CACHE;
 296                 if (DMU_OS_IS_L2COMPRESSIBLE(os))
 297                         aflags |= ARC_L2COMPRESS;
 298 
 299                 dprintf_bp(os->os_rootbp, "reading %s", "");
 300                 err = arc_read(NULL, spa, os->os_rootbp,
 301                     arc_getbuf_func, &os->os_phys_buf,
 302                     ZIO_PRIORITY_SYNC_READ, ZIO_FLAG_CANFAIL, &aflags, &zb);
 303                 if (err != 0) {
 304                         kmem_free(os, sizeof (objset_t));
 305                         /* convert checksum errors into IO errors */
 306                         if (err == ECKSUM)
 307                                 err = SET_ERROR(EIO);
 308                         return (err);
 309                 }
 310 
 311                 /* Increase the blocksize if we are permitted. */
 312                 if (spa_version(spa) >= SPA_VERSION_USERSPACE &&
 313                     arc_buf_size(os->os_phys_buf) < sizeof (objset_phys_t)) {
 314                         arc_buf_t *buf = arc_buf_alloc(spa,
 315                             sizeof (objset_phys_t), &os->os_phys_buf,
 316                             ARC_BUFC_METADATA);
 317                         bzero(buf->b_data, sizeof (objset_phys_t));
 318                         bcopy(os->os_phys_buf->b_data, buf->b_data,
 319                             arc_buf_size(os->os_phys_buf));
 320                         (void) arc_buf_remove_ref(os->os_phys_buf,
 321                             &os->os_phys_buf);
 322                         os->os_phys_buf = buf;
 323                 }
 324 
 325                 os->os_phys = os->os_phys_buf->b_data;
 326                 os->os_flags = os->os_phys->os_flags;
 327         } else {
 328                 int size = spa_version(spa) >= SPA_VERSION_USERSPACE ?
 329                     sizeof (objset_phys_t) : OBJSET_OLD_PHYS_SIZE;
 330                 os->os_phys_buf = arc_buf_alloc(spa, size,
 331                     &os->os_phys_buf, ARC_BUFC_METADATA);
 332                 os->os_phys = os->os_phys_buf->b_data;
 333                 bzero(os->os_phys, size);
 334         }
 335 
 336         /*
 337          * Note: the changed_cb will be called once before the register
 338          * func returns, thus changing the checksum/compression from the
 339          * default (fletcher2/off).  Snapshots don't need to know about
 340          * checksum/compression/copies.
 341          */
 342         if (ds != NULL) {
 343                 err = dsl_prop_register(ds,
 344                     zfs_prop_to_name(ZFS_PROP_PRIMARYCACHE),
 345                     primary_cache_changed_cb, os);
 346                 if (err == 0) {
 347                         err = dsl_prop_register(ds,
 348                             zfs_prop_to_name(ZFS_PROP_SECONDARYCACHE),
 349                             secondary_cache_changed_cb, os);
 350                 }
 351                 if (!dsl_dataset_is_snapshot(ds)) {
 352                         if (err == 0) {
 353                                 err = dsl_prop_register(ds,
 354                                     zfs_prop_to_name(ZFS_PROP_CHECKSUM),
 355                                     checksum_changed_cb, os);
 356                         }
 357                         if (err == 0) {
 358                                 err = dsl_prop_register(ds,
 359                                     zfs_prop_to_name(ZFS_PROP_COMPRESSION),
 360                                     compression_changed_cb, os);
 361                         }
 362                         if (err == 0) {
 363                                 err = dsl_prop_register(ds,
 364                                     zfs_prop_to_name(ZFS_PROP_COPIES),
 365                                     copies_changed_cb, os);
 366                         }
 367                         if (err == 0) {
 368                                 err = dsl_prop_register(ds,
 369                                     zfs_prop_to_name(ZFS_PROP_DEDUP),
 370                                     dedup_changed_cb, os);
 371                         }
 372                         if (err == 0) {
 373                                 err = dsl_prop_register(ds,
 374                                     zfs_prop_to_name(ZFS_PROP_LOGBIAS),
 375                                     logbias_changed_cb, os);
 376                         }
 377                         if (err == 0) {
 378                                 err = dsl_prop_register(ds,
 379                                     zfs_prop_to_name(ZFS_PROP_SYNC),
 380                                     sync_changed_cb, os);
 381                         }
 382                         if (err == 0) {
 383                                 err = dsl_prop_register(ds,
 384                                     zfs_prop_to_name(
 385                                     ZFS_PROP_REDUNDANT_METADATA),
 386                                     redundant_metadata_changed_cb, os);
 387                         }
 388                 }
 389                 if (err != 0) {
 390                         VERIFY(arc_buf_remove_ref(os->os_phys_buf,
 391                             &os->os_phys_buf));
 392                         kmem_free(os, sizeof (objset_t));
 393                         return (err);
 394                 }
 395         } else {
 396                 /* It's the meta-objset. */
 397                 os->os_checksum = ZIO_CHECKSUM_FLETCHER_4;
 398                 os->os_compress = ZIO_COMPRESS_LZJB;
 399                 os->os_copies = spa_max_replication(spa);
 400                 os->os_dedup_checksum = ZIO_CHECKSUM_OFF;
 401                 os->os_dedup_verify = B_FALSE;
 402                 os->os_logbias = ZFS_LOGBIAS_LATENCY;
 403                 os->os_sync = ZFS_SYNC_STANDARD;
 404                 os->os_primary_cache = ZFS_CACHE_ALL;
 405                 os->os_secondary_cache = ZFS_CACHE_ALL;
 406         }
 407 
 408         if (ds == NULL || !dsl_dataset_is_snapshot(ds))
 409                 os->os_zil_header = os->os_phys->os_zil_header;
 410         os->os_zil = zil_alloc(os, &os->os_zil_header);
 411 
 412         for (i = 0; i < TXG_SIZE; i++) {
 413                 list_create(&os->os_dirty_dnodes[i], sizeof (dnode_t),
 414                     offsetof(dnode_t, dn_dirty_link[i]));
 415                 list_create(&os->os_free_dnodes[i], sizeof (dnode_t),
 416                     offsetof(dnode_t, dn_dirty_link[i]));
 417         }
 418         list_create(&os->os_dnodes, sizeof (dnode_t),
 419             offsetof(dnode_t, dn_link));
 420         list_create(&os->os_downgraded_dbufs, sizeof (dmu_buf_impl_t),
 421             offsetof(dmu_buf_impl_t, db_link));
 422 
 423         mutex_init(&os->os_lock, NULL, MUTEX_DEFAULT, NULL);
 424         mutex_init(&os->os_obj_lock, NULL, MUTEX_DEFAULT, NULL);
 425         mutex_init(&os->os_user_ptr_lock, NULL, MUTEX_DEFAULT, NULL);
 426 
 427         DMU_META_DNODE(os) = dnode_special_open(os,
 428             &os->os_phys->os_meta_dnode, DMU_META_DNODE_OBJECT,
 429             &os->os_meta_dnode);
 430         if (arc_buf_size(os->os_phys_buf) >= sizeof (objset_phys_t)) {
 431                 DMU_USERUSED_DNODE(os) = dnode_special_open(os,
 432                     &os->os_phys->os_userused_dnode, DMU_USERUSED_OBJECT,
 433                     &os->os_userused_dnode);
 434                 DMU_GROUPUSED_DNODE(os) = dnode_special_open(os,
 435                     &os->os_phys->os_groupused_dnode, DMU_GROUPUSED_OBJECT,
 436                     &os->os_groupused_dnode);
 437         }
 438 
 439         *osp = os;
 440         return (0);
 441 }
 442 
 443 int
 444 dmu_objset_from_ds(dsl_dataset_t *ds, objset_t **osp)
 445 {
 446         int err = 0;
 447 
 448         mutex_enter(&ds->ds_opening_lock);
 449         if (ds->ds_objset == NULL) {
 450                 objset_t *os;
 451                 err = dmu_objset_open_impl(dsl_dataset_get_spa(ds),
 452                     ds, dsl_dataset_get_blkptr(ds), &os);
 453 
 454                 if (err == 0) {
 455                         mutex_enter(&ds->ds_lock);
 456                         ASSERT(ds->ds_objset == NULL);
 457                         ds->ds_objset = os;
 458                         mutex_exit(&ds->ds_lock);
 459                 }
 460         }
 461         *osp = ds->ds_objset;
 462         mutex_exit(&ds->ds_opening_lock);
 463         return (err);
 464 }
 465 
 466 /*
 467  * Holds the pool while the objset is held.  Therefore only one objset
 468  * can be held at a time.
 469  */
 470 static int
 471 dmu_objset_hold_impl(const char *name, void *tag, objset_t **osp, int lock)
 472 {
 473         dsl_pool_t *dp;
 474         dsl_dataset_t *ds;
 475         int err;
 476 
 477         err = dsl_pool_hold_lock(name, tag, &dp, lock);
 478         if (err != 0)
 479                 return (err);
 480         err = dsl_dataset_hold(dp, name, tag, &ds);
 481         if (err != 0) {
 482                 dsl_pool_rele(dp, tag);
 483                 return (err);
 484         }
 485 
 486         err = dmu_objset_from_ds(ds, osp);
 487         if (err != 0) {
 488                 dsl_dataset_rele(ds, tag);
 489                 dsl_pool_rele(dp, tag);
 490         }
 491 
 492         return (err);
 493 }
 494 
 495 int
 496 dmu_objset_hold(const char *name, void *tag, objset_t **osp)
 497 {
 498         return (dmu_objset_hold_impl(name, tag, osp, 1));
 499 }
 500 
 501 int
 502 dmu_objset_hold_nolock(const char *name, void *tag, objset_t **osp)
 503 {
 504         return (dmu_objset_hold_impl(name, tag, osp, 0));
 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 static int
 513 dmu_objset_own_impl(const char *name, dmu_objset_type_t type,
 514     boolean_t readonly, void *tag, objset_t **osp, int lock)
 515 {
 516         dsl_pool_t *dp;
 517         dsl_dataset_t *ds;
 518         int err;
 519 
 520         err = dsl_pool_hold_lock(name, FTAG, &dp, lock);
 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 && dsl_dataset_is_snapshot(ds)) {
 537                 dsl_dataset_disown(ds, tag);
 538                 return (SET_ERROR(EROFS));
 539         }
 540         return (err);
 541 }
 542 
 543 int
 544 dmu_objset_own(const char *name, dmu_objset_type_t type,
 545     boolean_t readonly, void *tag, objset_t **osp)
 546 {
 547         return (dmu_objset_own_impl(name, type, readonly, tag, osp, 1));
 548 }
 549 
 550 int
 551 dmu_objset_own_nolock(const char *name, dmu_objset_type_t type,
 552     boolean_t readonly, void *tag, objset_t **osp)
 553 {
 554         return (dmu_objset_own_impl(name, type, readonly, tag, osp, 0));
 555 }
 556 
 557 void
 558 dmu_objset_rele(objset_t *os, void *tag)
 559 {
 560         dsl_pool_t *dp = dmu_objset_pool(os);
 561         dsl_dataset_rele(os->os_dsl_dataset, tag);
 562         dsl_pool_rele(dp, tag);
 563 }
 564 
 565 /*
 566  * When we are called, os MUST refer to an objset associated with a dataset
 567  * that is owned by 'tag'; that is, is held and long held by 'tag' and ds_owner
 568  * == tag.  We will then release and reacquire ownership of the dataset while
 569  * holding the pool config_rwlock to avoid intervening namespace or ownership
 570  * changes may occur.
 571  *
 572  * This exists solely to accommodate zfs_ioc_userspace_upgrade()'s desire to
 573  * release the hold on its dataset and acquire a new one on the dataset of the
 574  * same name so that it can be partially torn down and reconstructed.
 575  */
 576 void
 577 dmu_objset_refresh_ownership(objset_t *os, void *tag)
 578 {
 579         dsl_pool_t *dp;
 580         dsl_dataset_t *ds, *newds;
 581         char name[MAXNAMELEN];
 582 
 583         ds = os->os_dsl_dataset;
 584         VERIFY3P(ds, !=, NULL);
 585         VERIFY3P(ds->ds_owner, ==, tag);
 586         VERIFY(dsl_dataset_long_held(ds));
 587 
 588         dsl_dataset_name(ds, name);
 589         dp = dmu_objset_pool(os);
 590         dsl_pool_config_enter(dp, FTAG);
 591         dmu_objset_disown(os, tag);
 592         VERIFY0(dsl_dataset_own(dp, name, tag, &newds));
 593         VERIFY3P(newds, ==, os->os_dsl_dataset);
 594         dsl_pool_config_exit(dp, FTAG);
 595 }
 596 
 597 void
 598 dmu_objset_disown(objset_t *os, void *tag)
 599 {
 600         dsl_dataset_disown(os->os_dsl_dataset, tag);
 601 }
 602 
 603 void
 604 dmu_objset_evict_dbufs(objset_t *os)
 605 {
 606         dnode_t *dn;
 607 
 608         mutex_enter(&os->os_lock);
 609 
 610         /* process the mdn last, since the other dnodes have holds on it */
 611         list_remove(&os->os_dnodes, DMU_META_DNODE(os));
 612         list_insert_tail(&os->os_dnodes, DMU_META_DNODE(os));
 613 
 614         /*
 615          * Find the first dnode with holds.  We have to do this dance
 616          * because dnode_add_ref() only works if you already have a
 617          * hold.  If there are no holds then it has no dbufs so OK to
 618          * skip.
 619          */
 620         for (dn = list_head(&os->os_dnodes);
 621             dn && !dnode_add_ref(dn, FTAG);
 622             dn = list_next(&os->os_dnodes, dn))
 623                 continue;
 624 
 625         while (dn) {
 626                 dnode_t *next_dn = dn;
 627 
 628                 do {
 629                         next_dn = list_next(&os->os_dnodes, next_dn);
 630                 } while (next_dn && !dnode_add_ref(next_dn, FTAG));
 631 
 632                 mutex_exit(&os->os_lock);
 633                 dnode_evict_dbufs(dn);
 634                 dnode_rele(dn, FTAG);
 635                 mutex_enter(&os->os_lock);
 636                 dn = next_dn;
 637         }
 638         mutex_exit(&os->os_lock);
 639 }
 640 
 641 void
 642 dmu_objset_evict(objset_t *os)
 643 {
 644         dsl_dataset_t *ds = os->os_dsl_dataset;
 645 
 646         for (int t = 0; t < TXG_SIZE; t++)
 647                 ASSERT(!dmu_objset_is_dirty(os, t));
 648 
 649         if (ds) {
 650                 if (!dsl_dataset_is_snapshot(ds)) {
 651                         VERIFY0(dsl_prop_unregister(ds,
 652                             zfs_prop_to_name(ZFS_PROP_CHECKSUM),
 653                             checksum_changed_cb, os));
 654                         VERIFY0(dsl_prop_unregister(ds,
 655                             zfs_prop_to_name(ZFS_PROP_COMPRESSION),
 656                             compression_changed_cb, os));
 657                         VERIFY0(dsl_prop_unregister(ds,
 658                             zfs_prop_to_name(ZFS_PROP_COPIES),
 659                             copies_changed_cb, os));
 660                         VERIFY0(dsl_prop_unregister(ds,
 661                             zfs_prop_to_name(ZFS_PROP_DEDUP),
 662                             dedup_changed_cb, os));
 663                         VERIFY0(dsl_prop_unregister(ds,
 664                             zfs_prop_to_name(ZFS_PROP_LOGBIAS),
 665                             logbias_changed_cb, os));
 666                         VERIFY0(dsl_prop_unregister(ds,
 667                             zfs_prop_to_name(ZFS_PROP_SYNC),
 668                             sync_changed_cb, os));
 669                         VERIFY0(dsl_prop_unregister(ds,
 670                             zfs_prop_to_name(ZFS_PROP_REDUNDANT_METADATA),
 671                             redundant_metadata_changed_cb, os));
 672                 }
 673                 VERIFY0(dsl_prop_unregister(ds,
 674                     zfs_prop_to_name(ZFS_PROP_PRIMARYCACHE),
 675                     primary_cache_changed_cb, os));
 676                 VERIFY0(dsl_prop_unregister(ds,
 677                     zfs_prop_to_name(ZFS_PROP_SECONDARYCACHE),
 678                     secondary_cache_changed_cb, os));
 679         }
 680 
 681         if (os->os_sa)
 682                 sa_tear_down(os);
 683 
 684         dmu_objset_evict_dbufs(os);
 685 
 686         dnode_special_close(&os->os_meta_dnode);
 687         if (DMU_USERUSED_DNODE(os)) {
 688                 dnode_special_close(&os->os_userused_dnode);
 689                 dnode_special_close(&os->os_groupused_dnode);
 690         }
 691         zil_free(os->os_zil);
 692 
 693         ASSERT3P(list_head(&os->os_dnodes), ==, NULL);
 694 
 695         VERIFY(arc_buf_remove_ref(os->os_phys_buf, &os->os_phys_buf));
 696 
 697         /*
 698          * This is a barrier to prevent the objset from going away in
 699          * dnode_move() until we can safely ensure that the objset is still in
 700          * use. We consider the objset valid before the barrier and invalid
 701          * after the barrier.
 702          */
 703         rw_enter(&os_lock, RW_READER);
 704         rw_exit(&os_lock);
 705 
 706         mutex_destroy(&os->os_lock);
 707         mutex_destroy(&os->os_obj_lock);
 708         mutex_destroy(&os->os_user_ptr_lock);
 709         kmem_free(os, sizeof (objset_t));
 710 }
 711 
 712 timestruc_t
 713 dmu_objset_snap_cmtime(objset_t *os)
 714 {
 715         return (dsl_dir_snap_cmtime(os->os_dsl_dataset->ds_dir));
 716 }
 717 
 718 /* called from dsl for meta-objset */
 719 objset_t *
 720 dmu_objset_create_impl(spa_t *spa, dsl_dataset_t *ds, blkptr_t *bp,
 721     dmu_objset_type_t type, dmu_tx_t *tx)
 722 {
 723         objset_t *os;
 724         dnode_t *mdn;
 725 
 726         ASSERT(dmu_tx_is_syncing(tx));
 727 
 728         if (ds != NULL)
 729                 VERIFY0(dmu_objset_from_ds(ds, &os));
 730         else
 731                 VERIFY0(dmu_objset_open_impl(spa, NULL, bp, &os));
 732 
 733         mdn = DMU_META_DNODE(os);
 734 
 735         dnode_allocate(mdn, DMU_OT_DNODE, 1 << DNODE_BLOCK_SHIFT,
 736             DN_MAX_INDBLKSHIFT, DMU_OT_NONE, 0, tx);
 737 
 738         /*
 739          * We don't want to have to increase the meta-dnode's nlevels
 740          * later, because then we could do it in quescing context while
 741          * we are also accessing it in open context.
 742          *
 743          * This precaution is not necessary for the MOS (ds == NULL),
 744          * because the MOS is only updated in syncing context.
 745          * This is most fortunate: the MOS is the only objset that
 746          * needs to be synced multiple times as spa_sync() iterates
 747          * to convergence, so minimizing its dn_nlevels matters.
 748          */
 749         if (ds != NULL) {
 750                 int levels = 1;
 751 
 752                 /*
 753                  * Determine the number of levels necessary for the meta-dnode
 754                  * to contain DN_MAX_OBJECT dnodes.
 755                  */
 756                 while ((uint64_t)mdn->dn_nblkptr << (mdn->dn_datablkshift +
 757                     (levels - 1) * (mdn->dn_indblkshift - SPA_BLKPTRSHIFT)) <
 758                     DN_MAX_OBJECT * sizeof (dnode_phys_t))
 759                         levels++;
 760 
 761                 mdn->dn_next_nlevels[tx->tx_txg & TXG_MASK] =
 762                     mdn->dn_nlevels = levels;
 763         }
 764 
 765         ASSERT(type != DMU_OST_NONE);
 766         ASSERT(type != DMU_OST_ANY);
 767         ASSERT(type < DMU_OST_NUMTYPES);
 768         os->os_phys->os_type = type;
 769         if (dmu_objset_userused_enabled(os)) {
 770                 os->os_phys->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
 771                 os->os_flags = os->os_phys->os_flags;
 772         }
 773 
 774         dsl_dataset_dirty(ds, tx);
 775 
 776         return (os);
 777 }
 778 
 779 typedef struct dmu_objset_create_arg {
 780         const char *doca_name;
 781         cred_t *doca_cred;
 782         void (*doca_userfunc)(objset_t *os, void *arg,
 783             cred_t *cr, dmu_tx_t *tx);
 784         void *doca_userarg;
 785         dmu_objset_type_t doca_type;
 786         uint64_t doca_flags;
 787 } dmu_objset_create_arg_t;
 788 
 789 /*ARGSUSED*/
 790 static int
 791 dmu_objset_create_check(void *arg, dmu_tx_t *tx)
 792 {
 793         dmu_objset_create_arg_t *doca = arg;
 794         dsl_pool_t *dp = dmu_tx_pool(tx);
 795         dsl_dir_t *pdd;
 796         const char *tail;
 797         int error;
 798 
 799         if (strchr(doca->doca_name, '@') != NULL)
 800                 return (SET_ERROR(EINVAL));
 801 
 802         error = dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail);
 803         if (error != 0)
 804                 return (error);
 805         if (tail == NULL) {
 806                 dsl_dir_rele(pdd, FTAG);
 807                 return (SET_ERROR(EEXIST));
 808         }
 809         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 810             doca->doca_cred);
 811         dsl_dir_rele(pdd, FTAG);
 812 
 813         return (error);
 814 }
 815 
 816 static void
 817 dmu_objset_create_sync(void *arg, dmu_tx_t *tx)
 818 {
 819         dmu_objset_create_arg_t *doca = arg;
 820         dsl_pool_t *dp = dmu_tx_pool(tx);
 821         dsl_dir_t *pdd;
 822         const char *tail;
 823         dsl_dataset_t *ds;
 824         uint64_t obj;
 825         blkptr_t *bp;
 826         objset_t *os;
 827 
 828         VERIFY0(dsl_dir_hold(dp, doca->doca_name, FTAG, &pdd, &tail));
 829 
 830         obj = dsl_dataset_create_sync(pdd, tail, NULL, doca->doca_flags,
 831             doca->doca_cred, tx);
 832 
 833         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 834         bp = dsl_dataset_get_blkptr(ds);
 835         os = dmu_objset_create_impl(pdd->dd_pool->dp_spa,
 836             ds, bp, doca->doca_type, tx);
 837 
 838         if (doca->doca_userfunc != NULL) {
 839                 doca->doca_userfunc(os, doca->doca_userarg,
 840                     doca->doca_cred, tx);
 841         }
 842 
 843         spa_history_log_internal_ds(ds, "create", tx, "");
 844         dsl_dataset_rele(ds, FTAG);
 845         dsl_dir_rele(pdd, FTAG);
 846 }
 847 
 848 int
 849 dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
 850     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg)
 851 {
 852         dmu_objset_create_arg_t doca;
 853 
 854         doca.doca_name = name;
 855         doca.doca_cred = CRED();
 856         doca.doca_flags = flags;
 857         doca.doca_userfunc = func;
 858         doca.doca_userarg = arg;
 859         doca.doca_type = type;
 860 
 861         return (dsl_sync_task(name,
 862             dmu_objset_create_check, dmu_objset_create_sync, &doca, 5));
 863 }
 864 
 865 typedef struct dmu_objset_clone_arg {
 866         const char *doca_clone;
 867         const char *doca_origin;
 868         cred_t *doca_cred;
 869 } dmu_objset_clone_arg_t;
 870 
 871 /*ARGSUSED*/
 872 static int
 873 dmu_objset_clone_check(void *arg, dmu_tx_t *tx)
 874 {
 875         dmu_objset_clone_arg_t *doca = arg;
 876         dsl_dir_t *pdd;
 877         const char *tail;
 878         int error;
 879         dsl_dataset_t *origin;
 880         dsl_pool_t *dp = dmu_tx_pool(tx);
 881 
 882         if (strchr(doca->doca_clone, '@') != NULL)
 883                 return (SET_ERROR(EINVAL));
 884 
 885         error = dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail);
 886         if (error != 0)
 887                 return (error);
 888         if (tail == NULL) {
 889                 dsl_dir_rele(pdd, FTAG);
 890                 return (SET_ERROR(EEXIST));
 891         }
 892         /* You can't clone across pools. */
 893         if (pdd->dd_pool != dp) {
 894                 dsl_dir_rele(pdd, FTAG);
 895                 return (SET_ERROR(EXDEV));
 896         }
 897         error = dsl_fs_ss_limit_check(pdd, 1, ZFS_PROP_FILESYSTEM_LIMIT, NULL,
 898             doca->doca_cred);
 899         if (error != 0) {
 900                 dsl_dir_rele(pdd, FTAG);
 901                 return (SET_ERROR(EDQUOT));
 902         }
 903         dsl_dir_rele(pdd, FTAG);
 904 
 905         error = dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin);
 906         if (error != 0)
 907                 return (error);
 908 
 909         /* You can't clone across pools. */
 910         if (origin->ds_dir->dd_pool != dp) {
 911                 dsl_dataset_rele(origin, FTAG);
 912                 return (SET_ERROR(EXDEV));
 913         }
 914 
 915         /* You can only clone snapshots, not the head datasets. */
 916         if (!dsl_dataset_is_snapshot(origin)) {
 917                 dsl_dataset_rele(origin, FTAG);
 918                 return (SET_ERROR(EINVAL));
 919         }
 920         dsl_dataset_rele(origin, FTAG);
 921 
 922         return (0);
 923 }
 924 
 925 static void
 926 dmu_objset_clone_sync(void *arg, dmu_tx_t *tx)
 927 {
 928         dmu_objset_clone_arg_t *doca = arg;
 929         dsl_pool_t *dp = dmu_tx_pool(tx);
 930         dsl_dir_t *pdd;
 931         const char *tail;
 932         dsl_dataset_t *origin, *ds;
 933         uint64_t obj;
 934         char namebuf[MAXNAMELEN];
 935 
 936         VERIFY0(dsl_dir_hold(dp, doca->doca_clone, FTAG, &pdd, &tail));
 937         VERIFY0(dsl_dataset_hold(dp, doca->doca_origin, FTAG, &origin));
 938 
 939         obj = dsl_dataset_create_sync(pdd, tail, origin, 0,
 940             doca->doca_cred, tx);
 941 
 942         VERIFY0(dsl_dataset_hold_obj(pdd->dd_pool, obj, FTAG, &ds));
 943         dsl_dataset_name(origin, namebuf);
 944         spa_history_log_internal_ds(ds, "clone", tx,
 945             "origin=%s (%llu)", namebuf, origin->ds_object);
 946         dsl_dataset_rele(ds, FTAG);
 947         dsl_dataset_rele(origin, FTAG);
 948         dsl_dir_rele(pdd, FTAG);
 949 }
 950 
 951 int
 952 dmu_objset_clone(const char *clone, const char *origin)
 953 {
 954         dmu_objset_clone_arg_t doca;
 955 
 956         doca.doca_clone = clone;
 957         doca.doca_origin = origin;
 958         doca.doca_cred = CRED();
 959 
 960         return (dsl_sync_task(clone,
 961             dmu_objset_clone_check, dmu_objset_clone_sync, &doca, 5));
 962 }
 963 
 964 int
 965 dmu_objset_snapshot_one(const char *fsname, const char *snapname)
 966 {
 967         int err;
 968         char *longsnap = kmem_asprintf("%s@%s", fsname, snapname);
 969         nvlist_t *snaps = fnvlist_alloc();
 970 
 971         fnvlist_add_boolean(snaps, longsnap);
 972         strfree(longsnap);
 973         err = dsl_dataset_snapshot(snaps, NULL, NULL);
 974         fnvlist_free(snaps);
 975         return (err);
 976 }
 977 
 978 static void
 979 dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
 980 {
 981         dnode_t *dn;
 982 
 983         while (dn = list_head(list)) {
 984                 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT);
 985                 ASSERT(dn->dn_dbuf->db_data_pending);
 986                 /*
 987                  * Initialize dn_zio outside dnode_sync() because the
 988                  * meta-dnode needs to set it ouside dnode_sync().
 989                  */
 990                 dn->dn_zio = dn->dn_dbuf->db_data_pending->dr_zio;
 991                 ASSERT(dn->dn_zio);
 992 
 993                 ASSERT3U(dn->dn_nlevels, <=, DN_MAX_LEVELS);
 994                 list_remove(list, dn);
 995 
 996                 if (newlist) {
 997                         (void) dnode_add_ref(dn, newlist);
 998                         list_insert_tail(newlist, dn);
 999                 }
1000 
1001                 dnode_sync(dn, tx);
1002         }
1003 }
1004 
1005 /* ARGSUSED */
1006 static void
1007 dmu_objset_write_ready(zio_t *zio, arc_buf_t *abuf, void *arg)
1008 {
1009         blkptr_t *bp = zio->io_bp;
1010         objset_t *os = arg;
1011         dnode_phys_t *dnp = &os->os_phys->os_meta_dnode;
1012 
1013         ASSERT(!BP_IS_EMBEDDED(bp));
1014         ASSERT3P(bp, ==, os->os_rootbp);
1015         ASSERT3U(BP_GET_TYPE(bp), ==, DMU_OT_OBJSET);
1016         ASSERT0(BP_GET_LEVEL(bp));
1017 
1018         /*
1019          * Update rootbp fill count: it should be the number of objects
1020          * allocated in the object set (not counting the "special"
1021          * objects that are stored in the objset_phys_t -- the meta
1022          * dnode and user/group accounting objects).
1023          */
1024         bp->blk_fill = 0;
1025         for (int i = 0; i < dnp->dn_nblkptr; i++)
1026                 bp->blk_fill += BP_GET_FILL(&dnp->dn_blkptr[i]);
1027 }
1028 
1029 /* ARGSUSED */
1030 static void
1031 dmu_objset_write_done(zio_t *zio, arc_buf_t *abuf, void *arg)
1032 {
1033         blkptr_t *bp = zio->io_bp;
1034         blkptr_t *bp_orig = &zio->io_bp_orig;
1035         objset_t *os = arg;
1036 
1037         if (zio->io_flags & ZIO_FLAG_IO_REWRITE) {
1038                 ASSERT(BP_EQUAL(bp, bp_orig));
1039         } else {
1040                 dsl_dataset_t *ds = os->os_dsl_dataset;
1041                 dmu_tx_t *tx = os->os_synctx;
1042 
1043                 (void) dsl_dataset_block_kill(ds, bp_orig, tx, B_TRUE);
1044                 dsl_dataset_block_born(ds, bp, tx);
1045         }
1046 }
1047 
1048 /* called from dsl */
1049 void
1050 dmu_objset_sync(objset_t *os, zio_t *pio, dmu_tx_t *tx)
1051 {
1052         int txgoff;
1053         zbookmark_t zb;
1054         zio_prop_t zp;
1055         zio_t *zio;
1056         list_t *list;
1057         list_t *newlist = NULL;
1058         dbuf_dirty_record_t *dr;
1059 
1060         dprintf_ds(os->os_dsl_dataset, "txg=%llu\n", tx->tx_txg);
1061 
1062         ASSERT(dmu_tx_is_syncing(tx));
1063         /* XXX the write_done callback should really give us the tx... */
1064         os->os_synctx = tx;
1065 
1066         if (os->os_dsl_dataset == NULL) {
1067                 /*
1068                  * This is the MOS.  If we have upgraded,
1069                  * spa_max_replication() could change, so reset
1070                  * os_copies here.
1071                  */
1072                 os->os_copies = spa_max_replication(os->os_spa);
1073         }
1074 
1075         /*
1076          * Create the root block IO
1077          */
1078         SET_BOOKMARK(&zb, os->os_dsl_dataset ?
1079             os->os_dsl_dataset->ds_object : DMU_META_OBJSET,
1080             ZB_ROOT_OBJECT, ZB_ROOT_LEVEL, ZB_ROOT_BLKID);
1081         arc_release(os->os_phys_buf, &os->os_phys_buf);
1082 
1083         dmu_write_policy(os, NULL, 0, 0, &zp);
1084 
1085         zio = arc_write(pio, os->os_spa, tx->tx_txg,
1086             os->os_rootbp, os->os_phys_buf, DMU_OS_IS_L2CACHEABLE(os),
1087             DMU_OS_IS_L2COMPRESSIBLE(os), &zp, dmu_objset_write_ready,
1088             NULL, dmu_objset_write_done, os, ZIO_PRIORITY_ASYNC_WRITE,
1089             ZIO_FLAG_MUSTSUCCEED, &zb);
1090 
1091         /*
1092          * Sync special dnodes - the parent IO for the sync is the root block
1093          */
1094         DMU_META_DNODE(os)->dn_zio = zio;
1095         dnode_sync(DMU_META_DNODE(os), tx);
1096 
1097         os->os_phys->os_flags = os->os_flags;
1098 
1099         if (DMU_USERUSED_DNODE(os) &&
1100             DMU_USERUSED_DNODE(os)->dn_type != DMU_OT_NONE) {
1101                 DMU_USERUSED_DNODE(os)->dn_zio = zio;
1102                 dnode_sync(DMU_USERUSED_DNODE(os), tx);
1103                 DMU_GROUPUSED_DNODE(os)->dn_zio = zio;
1104                 dnode_sync(DMU_GROUPUSED_DNODE(os), tx);
1105         }
1106 
1107         txgoff = tx->tx_txg & TXG_MASK;
1108 
1109         if (dmu_objset_userused_enabled(os)) {
1110                 newlist = &os->os_synced_dnodes;
1111                 /*
1112                  * We must create the list here because it uses the
1113                  * dn_dirty_link[] of this txg.
1114                  */
1115                 list_create(newlist, sizeof (dnode_t),
1116                     offsetof(dnode_t, dn_dirty_link[txgoff]));
1117         }
1118 
1119         dmu_objset_sync_dnodes(&os->os_free_dnodes[txgoff], newlist, tx);
1120         dmu_objset_sync_dnodes(&os->os_dirty_dnodes[txgoff], newlist, tx);
1121 
1122         list = &DMU_META_DNODE(os)->dn_dirty_records[txgoff];
1123         while (dr = list_head(list)) {
1124                 ASSERT0(dr->dr_dbuf->db_level);
1125                 list_remove(list, dr);
1126                 if (dr->dr_zio)
1127                         zio_nowait(dr->dr_zio);
1128         }
1129         /*
1130          * Free intent log blocks up to this tx.
1131          */
1132         zil_sync(os->os_zil, tx);
1133         os->os_phys->os_zil_header = os->os_zil_header;
1134         zio_nowait(zio);
1135 }
1136 
1137 boolean_t
1138 dmu_objset_is_dirty(objset_t *os, uint64_t txg)
1139 {
1140         return (!list_is_empty(&os->os_dirty_dnodes[txg & TXG_MASK]) ||
1141             !list_is_empty(&os->os_free_dnodes[txg & TXG_MASK]));
1142 }
1143 
1144 static objset_used_cb_t *used_cbs[DMU_OST_NUMTYPES];
1145 
1146 void
1147 dmu_objset_register_type(dmu_objset_type_t ost, objset_used_cb_t *cb)
1148 {
1149         used_cbs[ost] = cb;
1150 }
1151 
1152 boolean_t
1153 dmu_objset_userused_enabled(objset_t *os)
1154 {
1155         return (spa_version(os->os_spa) >= SPA_VERSION_USERSPACE &&
1156             used_cbs[os->os_phys->os_type] != NULL &&
1157             DMU_USERUSED_DNODE(os) != NULL);
1158 }
1159 
1160 static void
1161 do_userquota_update(objset_t *os, uint64_t used, uint64_t flags,
1162     uint64_t user, uint64_t group, boolean_t subtract, dmu_tx_t *tx)
1163 {
1164         if ((flags & DNODE_FLAG_USERUSED_ACCOUNTED)) {
1165                 int64_t delta = DNODE_SIZE + used;
1166                 if (subtract)
1167                         delta = -delta;
1168                 VERIFY3U(0, ==, zap_increment_int(os, DMU_USERUSED_OBJECT,
1169                     user, delta, tx));
1170                 VERIFY3U(0, ==, zap_increment_int(os, DMU_GROUPUSED_OBJECT,
1171                     group, delta, tx));
1172         }
1173 }
1174 
1175 void
1176 dmu_objset_do_userquota_updates(objset_t *os, dmu_tx_t *tx)
1177 {
1178         dnode_t *dn;
1179         list_t *list = &os->os_synced_dnodes;
1180 
1181         ASSERT(list_head(list) == NULL || dmu_objset_userused_enabled(os));
1182 
1183         while (dn = list_head(list)) {
1184                 int flags;
1185                 ASSERT(!DMU_OBJECT_IS_SPECIAL(dn->dn_object));
1186                 ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE ||
1187                     dn->dn_phys->dn_flags &
1188                     DNODE_FLAG_USERUSED_ACCOUNTED);
1189 
1190                 /* Allocate the user/groupused objects if necessary. */
1191                 if (DMU_USERUSED_DNODE(os)->dn_type == DMU_OT_NONE) {
1192                         VERIFY(0 == zap_create_claim(os,
1193                             DMU_USERUSED_OBJECT,
1194                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1195                         VERIFY(0 == zap_create_claim(os,
1196                             DMU_GROUPUSED_OBJECT,
1197                             DMU_OT_USERGROUP_USED, DMU_OT_NONE, 0, tx));
1198                 }
1199 
1200                 /*
1201                  * We intentionally modify the zap object even if the
1202                  * net delta is zero.  Otherwise
1203                  * the block of the zap obj could be shared between
1204                  * datasets but need to be different between them after
1205                  * a bprewrite.
1206                  */
1207 
1208                 flags = dn->dn_id_flags;
1209                 ASSERT(flags);
1210                 if (flags & DN_ID_OLD_EXIST)  {
1211                         do_userquota_update(os, dn->dn_oldused, dn->dn_oldflags,
1212                             dn->dn_olduid, dn->dn_oldgid, B_TRUE, tx);
1213                 }
1214                 if (flags & DN_ID_NEW_EXIST) {
1215                         do_userquota_update(os, DN_USED_BYTES(dn->dn_phys),
1216                             dn->dn_phys->dn_flags,  dn->dn_newuid,
1217                             dn->dn_newgid, B_FALSE, tx);
1218                 }
1219 
1220                 mutex_enter(&dn->dn_mtx);
1221                 dn->dn_oldused = 0;
1222                 dn->dn_oldflags = 0;
1223                 if (dn->dn_id_flags & DN_ID_NEW_EXIST) {
1224                         dn->dn_olduid = dn->dn_newuid;
1225                         dn->dn_oldgid = dn->dn_newgid;
1226                         dn->dn_id_flags |= DN_ID_OLD_EXIST;
1227                         if (dn->dn_bonuslen == 0)
1228                                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1229                         else
1230                                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1231                 }
1232                 dn->dn_id_flags &= ~(DN_ID_NEW_EXIST);
1233                 mutex_exit(&dn->dn_mtx);
1234 
1235                 list_remove(list, dn);
1236                 dnode_rele(dn, list);
1237         }
1238 }
1239 
1240 /*
1241  * Returns a pointer to data to find uid/gid from
1242  *
1243  * If a dirty record for transaction group that is syncing can't
1244  * be found then NULL is returned.  In the NULL case it is assumed
1245  * the uid/gid aren't changing.
1246  */
1247 static void *
1248 dmu_objset_userquota_find_data(dmu_buf_impl_t *db, dmu_tx_t *tx)
1249 {
1250         dbuf_dirty_record_t *dr, **drp;
1251         void *data;
1252 
1253         if (db->db_dirtycnt == 0)
1254                 return (db->db.db_data);  /* Nothing is changing */
1255 
1256         for (drp = &db->db_last_dirty; (dr = *drp) != NULL; drp = &dr->dr_next)
1257                 if (dr->dr_txg == tx->tx_txg)
1258                         break;
1259 
1260         if (dr == NULL) {
1261                 data = NULL;
1262         } else {
1263                 dnode_t *dn;
1264 
1265                 DB_DNODE_ENTER(dr->dr_dbuf);
1266                 dn = DB_DNODE(dr->dr_dbuf);
1267 
1268                 if (dn->dn_bonuslen == 0 &&
1269                     dr->dr_dbuf->db_blkid == DMU_SPILL_BLKID)
1270                         data = dr->dt.dl.dr_data->b_data;
1271                 else
1272                         data = dr->dt.dl.dr_data;
1273 
1274                 DB_DNODE_EXIT(dr->dr_dbuf);
1275         }
1276 
1277         return (data);
1278 }
1279 
1280 void
1281 dmu_objset_userquota_get_ids(dnode_t *dn, boolean_t before, dmu_tx_t *tx)
1282 {
1283         objset_t *os = dn->dn_objset;
1284         void *data = NULL;
1285         dmu_buf_impl_t *db = NULL;
1286         uint64_t *user = NULL;
1287         uint64_t *group = NULL;
1288         int flags = dn->dn_id_flags;
1289         int error;
1290         boolean_t have_spill = B_FALSE;
1291 
1292         if (!dmu_objset_userused_enabled(dn->dn_objset))
1293                 return;
1294 
1295         if (before && (flags & (DN_ID_CHKED_BONUS|DN_ID_OLD_EXIST|
1296             DN_ID_CHKED_SPILL)))
1297                 return;
1298 
1299         if (before && dn->dn_bonuslen != 0)
1300                 data = DN_BONUS(dn->dn_phys);
1301         else if (!before && dn->dn_bonuslen != 0) {
1302                 if (dn->dn_bonus) {
1303                         db = dn->dn_bonus;
1304                         mutex_enter(&db->db_mtx);
1305                         data = dmu_objset_userquota_find_data(db, tx);
1306                 } else {
1307                         data = DN_BONUS(dn->dn_phys);
1308                 }
1309         } else if (dn->dn_bonuslen == 0 && dn->dn_bonustype == DMU_OT_SA) {
1310                         int rf = 0;
1311 
1312                         if (RW_WRITE_HELD(&dn->dn_struct_rwlock))
1313                                 rf |= DB_RF_HAVESTRUCT;
1314                         error = dmu_spill_hold_by_dnode(dn,
1315                             rf | DB_RF_MUST_SUCCEED,
1316                             FTAG, (dmu_buf_t **)&db);
1317                         ASSERT(error == 0);
1318                         mutex_enter(&db->db_mtx);
1319                         data = (before) ? db->db.db_data :
1320                             dmu_objset_userquota_find_data(db, tx);
1321                         have_spill = B_TRUE;
1322         } else {
1323                 mutex_enter(&dn->dn_mtx);
1324                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1325                 mutex_exit(&dn->dn_mtx);
1326                 return;
1327         }
1328 
1329         if (before) {
1330                 ASSERT(data);
1331                 user = &dn->dn_olduid;
1332                 group = &dn->dn_oldgid;
1333         } else if (data) {
1334                 user = &dn->dn_newuid;
1335                 group = &dn->dn_newgid;
1336         }
1337 
1338         /*
1339          * Must always call the callback in case the object
1340          * type has changed and that type isn't an object type to track
1341          */
1342         error = used_cbs[os->os_phys->os_type](dn->dn_bonustype, data,
1343             user, group);
1344 
1345         /*
1346          * Preserve existing uid/gid when the callback can't determine
1347          * what the new uid/gid are and the callback returned EEXIST.
1348          * The EEXIST error tells us to just use the existing uid/gid.
1349          * If we don't know what the old values are then just assign
1350          * them to 0, since that is a new file  being created.
1351          */
1352         if (!before && data == NULL && error == EEXIST) {
1353                 if (flags & DN_ID_OLD_EXIST) {
1354                         dn->dn_newuid = dn->dn_olduid;
1355                         dn->dn_newgid = dn->dn_oldgid;
1356                 } else {
1357                         dn->dn_newuid = 0;
1358                         dn->dn_newgid = 0;
1359                 }
1360                 error = 0;
1361         }
1362 
1363         if (db)
1364                 mutex_exit(&db->db_mtx);
1365 
1366         mutex_enter(&dn->dn_mtx);
1367         if (error == 0 && before)
1368                 dn->dn_id_flags |= DN_ID_OLD_EXIST;
1369         if (error == 0 && !before)
1370                 dn->dn_id_flags |= DN_ID_NEW_EXIST;
1371 
1372         if (have_spill) {
1373                 dn->dn_id_flags |= DN_ID_CHKED_SPILL;
1374         } else {
1375                 dn->dn_id_flags |= DN_ID_CHKED_BONUS;
1376         }
1377         mutex_exit(&dn->dn_mtx);
1378         if (have_spill)
1379                 dmu_buf_rele((dmu_buf_t *)db, FTAG);
1380 }
1381 
1382 boolean_t
1383 dmu_objset_userspace_present(objset_t *os)
1384 {
1385         return (os->os_phys->os_flags &
1386             OBJSET_FLAG_USERACCOUNTING_COMPLETE);
1387 }
1388 
1389 int
1390 dmu_objset_userspace_upgrade(objset_t *os)
1391 {
1392         uint64_t obj;
1393         int err = 0;
1394 
1395         if (dmu_objset_userspace_present(os))
1396                 return (0);
1397         if (!dmu_objset_userused_enabled(os))
1398                 return (SET_ERROR(ENOTSUP));
1399         if (dmu_objset_is_snapshot(os))
1400                 return (SET_ERROR(EINVAL));
1401 
1402         /*
1403          * We simply need to mark every object dirty, so that it will be
1404          * synced out and now accounted.  If this is called
1405          * concurrently, or if we already did some work before crashing,
1406          * that's fine, since we track each object's accounted state
1407          * independently.
1408          */
1409 
1410         for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE, 0)) {
1411                 dmu_tx_t *tx;
1412                 dmu_buf_t *db;
1413                 int objerr;
1414 
1415                 if (issig(JUSTLOOKING) && issig(FORREAL))
1416                         return (SET_ERROR(EINTR));
1417 
1418                 objerr = dmu_bonus_hold(os, obj, FTAG, &db);
1419                 if (objerr != 0)
1420                         continue;
1421                 tx = dmu_tx_create(os);
1422                 dmu_tx_hold_bonus(tx, obj);
1423                 objerr = dmu_tx_assign(tx, TXG_WAIT);
1424                 if (objerr != 0) {
1425                         dmu_tx_abort(tx);
1426                         continue;
1427                 }
1428                 dmu_buf_will_dirty(db, tx);
1429                 dmu_buf_rele(db, FTAG);
1430                 dmu_tx_commit(tx);
1431         }
1432 
1433         os->os_flags |= OBJSET_FLAG_USERACCOUNTING_COMPLETE;
1434         txg_wait_synced(dmu_objset_pool(os), 0);
1435         return (0);
1436 }
1437 
1438 void
1439 dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
1440     uint64_t *usedobjsp, uint64_t *availobjsp)
1441 {
1442         dsl_dataset_space(os->os_dsl_dataset, refdbytesp, availbytesp,
1443             usedobjsp, availobjsp);
1444 }
1445 
1446 uint64_t
1447 dmu_objset_fsid_guid(objset_t *os)
1448 {
1449         return (dsl_dataset_fsid_guid(os->os_dsl_dataset));
1450 }
1451 
1452 void
1453 dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat)
1454 {
1455         stat->dds_type = os->os_phys->os_type;
1456         if (os->os_dsl_dataset)
1457                 dsl_dataset_fast_stat(os->os_dsl_dataset, stat);
1458 }
1459 
1460 void
1461 dmu_objset_stats(objset_t *os, nvlist_t *nv)
1462 {
1463         ASSERT(os->os_dsl_dataset ||
1464             os->os_phys->os_type == DMU_OST_META);
1465 
1466         if (os->os_dsl_dataset != NULL)
1467                 dsl_dataset_stats(os->os_dsl_dataset, nv);
1468 
1469         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_TYPE,
1470             os->os_phys->os_type);
1471         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERACCOUNTING,
1472             dmu_objset_userspace_present(os));
1473 }
1474 
1475 int
1476 dmu_objset_is_snapshot(objset_t *os)
1477 {
1478         if (os->os_dsl_dataset != NULL)
1479                 return (dsl_dataset_is_snapshot(os->os_dsl_dataset));
1480         else
1481                 return (B_FALSE);
1482 }
1483 
1484 int
1485 dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen,
1486     boolean_t *conflict)
1487 {
1488         dsl_dataset_t *ds = os->os_dsl_dataset;
1489         uint64_t ignored;
1490 
1491         if (ds->ds_phys->ds_snapnames_zapobj == 0)
1492                 return (SET_ERROR(ENOENT));
1493 
1494         return (zap_lookup_norm(ds->ds_dir->dd_pool->dp_meta_objset,
1495             ds->ds_phys->ds_snapnames_zapobj, name, 8, 1, &ignored, MT_FIRST,
1496             real, maxlen, conflict));
1497 }
1498 
1499 int
1500 dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
1501     uint64_t *idp, uint64_t *offp, boolean_t *case_conflict)
1502 {
1503         dsl_dataset_t *ds = os->os_dsl_dataset;
1504         zap_cursor_t cursor;
1505         zap_attribute_t attr;
1506 
1507         ASSERT(dsl_pool_config_held(dmu_objset_pool(os)));
1508 
1509         if (ds->ds_phys->ds_snapnames_zapobj == 0)
1510                 return (SET_ERROR(ENOENT));
1511 
1512         zap_cursor_init_serialized(&cursor,
1513             ds->ds_dir->dd_pool->dp_meta_objset,
1514             ds->ds_phys->ds_snapnames_zapobj, *offp);
1515 
1516         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1517                 zap_cursor_fini(&cursor);
1518                 return (SET_ERROR(ENOENT));
1519         }
1520 
1521         if (strlen(attr.za_name) + 1 > namelen) {
1522                 zap_cursor_fini(&cursor);
1523                 return (SET_ERROR(ENAMETOOLONG));
1524         }
1525 
1526         (void) strcpy(name, attr.za_name);
1527         if (idp)
1528                 *idp = attr.za_first_integer;
1529         if (case_conflict)
1530                 *case_conflict = attr.za_normalization_conflict;
1531         zap_cursor_advance(&cursor);
1532         *offp = zap_cursor_serialize(&cursor);
1533         zap_cursor_fini(&cursor);
1534 
1535         return (0);
1536 }
1537 
1538 int
1539 dmu_dir_list_next(objset_t *os, int namelen, char *name,
1540     uint64_t *idp, uint64_t *offp)
1541 {
1542         dsl_dir_t *dd = os->os_dsl_dataset->ds_dir;
1543         zap_cursor_t cursor;
1544         zap_attribute_t attr;
1545 
1546         /* there is no next dir on a snapshot! */
1547         if (os->os_dsl_dataset->ds_object !=
1548             dd->dd_phys->dd_head_dataset_obj)
1549                 return (SET_ERROR(ENOENT));
1550 
1551         zap_cursor_init_serialized(&cursor,
1552             dd->dd_pool->dp_meta_objset,
1553             dd->dd_phys->dd_child_dir_zapobj, *offp);
1554 
1555         if (zap_cursor_retrieve(&cursor, &attr) != 0) {
1556                 zap_cursor_fini(&cursor);
1557                 return (SET_ERROR(ENOENT));
1558         }
1559 
1560         if (strlen(attr.za_name) + 1 > namelen) {
1561                 zap_cursor_fini(&cursor);
1562                 return (SET_ERROR(ENAMETOOLONG));
1563         }
1564 
1565         (void) strcpy(name, attr.za_name);
1566         if (idp)
1567                 *idp = attr.za_first_integer;
1568         zap_cursor_advance(&cursor);
1569         *offp = zap_cursor_serialize(&cursor);
1570         zap_cursor_fini(&cursor);
1571 
1572         return (0);
1573 }
1574 
1575 /*
1576  * Find objsets under and including ddobj, call func(ds) on each.
1577  */
1578 int
1579 dmu_objset_find_dp(dsl_pool_t *dp, uint64_t ddobj,
1580     int func(dsl_pool_t *, dsl_dataset_t *, void *), void *arg, int flags)
1581 {
1582         dsl_dir_t *dd;
1583         dsl_dataset_t *ds;
1584         zap_cursor_t zc;
1585         zap_attribute_t *attr;
1586         uint64_t thisobj;
1587         int err;
1588 
1589         ASSERT(dsl_pool_config_held(dp));
1590 
1591         err = dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd);
1592         if (err != 0)
1593                 return (err);
1594 
1595         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1596         if (dd->dd_myname[0] == '$') {
1597                 dsl_dir_rele(dd, FTAG);
1598                 return (0);
1599         }
1600 
1601         thisobj = dd->dd_phys->dd_head_dataset_obj;
1602         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1603 
1604         /*
1605          * Iterate over all children.
1606          */
1607         if (flags & DS_FIND_CHILDREN) {
1608                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1609                     dd->dd_phys->dd_child_dir_zapobj);
1610                     zap_cursor_retrieve(&zc, attr) == 0;
1611                     (void) zap_cursor_advance(&zc)) {
1612                         ASSERT3U(attr->za_integer_length, ==,
1613                             sizeof (uint64_t));
1614                         ASSERT3U(attr->za_num_integers, ==, 1);
1615 
1616                         err = dmu_objset_find_dp(dp, attr->za_first_integer,
1617                             func, arg, flags);
1618                         if (err != 0)
1619                                 break;
1620                 }
1621                 zap_cursor_fini(&zc);
1622 
1623                 if (err != 0) {
1624                         dsl_dir_rele(dd, FTAG);
1625                         kmem_free(attr, sizeof (zap_attribute_t));
1626                         return (err);
1627                 }
1628         }
1629 
1630         /*
1631          * Iterate over all snapshots.
1632          */
1633         if (flags & DS_FIND_SNAPSHOTS) {
1634                 dsl_dataset_t *ds;
1635                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1636 
1637                 if (err == 0) {
1638                         uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
1639                         dsl_dataset_rele(ds, FTAG);
1640 
1641                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1642                             zap_cursor_retrieve(&zc, attr) == 0;
1643                             (void) zap_cursor_advance(&zc)) {
1644                                 ASSERT3U(attr->za_integer_length, ==,
1645                                     sizeof (uint64_t));
1646                                 ASSERT3U(attr->za_num_integers, ==, 1);
1647 
1648                                 err = dsl_dataset_hold_obj(dp,
1649                                     attr->za_first_integer, FTAG, &ds);
1650                                 if (err != 0)
1651                                         break;
1652                                 err = func(dp, ds, arg);
1653                                 dsl_dataset_rele(ds, FTAG);
1654                                 if (err != 0)
1655                                         break;
1656                         }
1657                         zap_cursor_fini(&zc);
1658                 }
1659         }
1660 
1661         dsl_dir_rele(dd, FTAG);
1662         kmem_free(attr, sizeof (zap_attribute_t));
1663 
1664         if (err != 0)
1665                 return (err);
1666 
1667         /*
1668          * Apply to self.
1669          */
1670         err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1671         if (err != 0)
1672                 return (err);
1673         err = func(dp, ds, arg);
1674         dsl_dataset_rele(ds, FTAG);
1675         return (err);
1676 }
1677 
1678 /*
1679  * Find all objsets under name, and for each, call 'func(child_name, arg)'.
1680  * The dp_config_rwlock must not be held when this is called, and it
1681  * will not be held when the callback is called.
1682  * Therefore this function should only be used when the pool is not changing
1683  * (e.g. in syncing context), or the callback can deal with the possible races.
1684  */
1685 static int
1686 dmu_objset_find_impl(spa_t *spa, const char *name,
1687     int func(const char *, void *), void *arg, int flags)
1688 {
1689         dsl_dir_t *dd;
1690         dsl_pool_t *dp = spa_get_dsl(spa);
1691         dsl_dataset_t *ds;
1692         zap_cursor_t zc;
1693         zap_attribute_t *attr;
1694         char *child;
1695         uint64_t thisobj;
1696         int err;
1697 
1698         dsl_pool_config_enter(dp, FTAG);
1699 
1700         err = dsl_dir_hold(dp, name, FTAG, &dd, NULL);
1701         if (err != 0) {
1702                 dsl_pool_config_exit(dp, FTAG);
1703                 return (err);
1704         }
1705 
1706         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1707         if (dd->dd_myname[0] == '$') {
1708                 dsl_dir_rele(dd, FTAG);
1709                 dsl_pool_config_exit(dp, FTAG);
1710                 return (0);
1711         }
1712 
1713         thisobj = dd->dd_phys->dd_head_dataset_obj;
1714         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1715 
1716         /*
1717          * Iterate over all children.
1718          */
1719         if (flags & DS_FIND_CHILDREN) {
1720                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1721                     dd->dd_phys->dd_child_dir_zapobj);
1722                     zap_cursor_retrieve(&zc, attr) == 0;
1723                     (void) zap_cursor_advance(&zc)) {
1724                         ASSERT3U(attr->za_integer_length, ==,
1725                             sizeof (uint64_t));
1726                         ASSERT3U(attr->za_num_integers, ==, 1);
1727 
1728                         child = kmem_asprintf("%s/%s", name, attr->za_name);
1729                         dsl_pool_config_exit(dp, FTAG);
1730                         err = dmu_objset_find_impl(spa, child,
1731                             func, arg, flags);
1732                         dsl_pool_config_enter(dp, FTAG);
1733                         strfree(child);
1734                         if (err != 0)
1735                                 break;
1736                 }
1737                 zap_cursor_fini(&zc);
1738 
1739                 if (err != 0) {
1740                         dsl_dir_rele(dd, FTAG);
1741                         dsl_pool_config_exit(dp, FTAG);
1742                         kmem_free(attr, sizeof (zap_attribute_t));
1743                         return (err);
1744                 }
1745         }
1746 
1747         /*
1748          * Iterate over all snapshots.
1749          */
1750         if (flags & DS_FIND_SNAPSHOTS) {
1751                 err = dsl_dataset_hold_obj(dp, thisobj, FTAG, &ds);
1752 
1753                 if (err == 0) {
1754                         uint64_t snapobj = ds->ds_phys->ds_snapnames_zapobj;
1755                         dsl_dataset_rele(ds, FTAG);
1756 
1757                         for (zap_cursor_init(&zc, dp->dp_meta_objset, snapobj);
1758                             zap_cursor_retrieve(&zc, attr) == 0;
1759                             (void) zap_cursor_advance(&zc)) {
1760                                 ASSERT3U(attr->za_integer_length, ==,
1761                                     sizeof (uint64_t));
1762                                 ASSERT3U(attr->za_num_integers, ==, 1);
1763 
1764                                 child = kmem_asprintf("%s@%s",
1765                                     name, attr->za_name);
1766                                 dsl_pool_config_exit(dp, FTAG);
1767                                 err = func(child, arg);
1768                                 dsl_pool_config_enter(dp, FTAG);
1769                                 strfree(child);
1770                                 if (err != 0)
1771                                         break;
1772                         }
1773                         zap_cursor_fini(&zc);
1774                 }
1775         }
1776 
1777         dsl_dir_rele(dd, FTAG);
1778         kmem_free(attr, sizeof (zap_attribute_t));
1779         dsl_pool_config_exit(dp, FTAG);
1780 
1781         if (err != 0)
1782                 return (err);
1783 
1784         /* Apply to self. */
1785         return (func(name, arg));
1786 }
1787 
1788 /*
1789  * See comment above dmu_objset_find_impl().
1790  */
1791 int
1792 dmu_objset_find(char *name, int func(const char *, void *), void *arg,
1793     int flags)
1794 {
1795         spa_t *spa;
1796         int error;
1797 
1798         error = spa_open(name, &spa, FTAG);
1799         if (error != 0)
1800                 return (error);
1801         error = dmu_objset_find_impl(spa, name, func, arg, flags);
1802         spa_close(spa, FTAG);
1803 
1804         return (error);
1805 }
1806 
1807 typedef struct dmu_objset_find_ctx {
1808         taskq_t         *dc_tq;
1809         spa_t           *dc_spa;
1810         char            *dc_name;
1811         int             (*dc_func)(const char *, void *);
1812         void            *dc_arg;
1813         int             dc_flags;
1814         kmutex_t        *dc_error_lock;
1815         int             *dc_error;
1816 } dmu_objset_find_ctx_t;
1817 
1818 static void
1819 dmu_objset_find_parallel_impl(void *arg)
1820 {
1821         dmu_objset_find_ctx_t *dcp = arg;
1822         dsl_dir_t *dd;
1823         dsl_pool_t *dp = spa_get_dsl(dcp->dc_spa);
1824         dsl_dataset_t *ds;
1825         zap_cursor_t zc;
1826         zap_attribute_t *attr;
1827         char *child;
1828         dmu_objset_find_ctx_t *child_dcp;
1829         uint64_t thisobj;
1830         int err;
1831 
1832         /* don't process if there already was an error */
1833         if (*dcp->dc_error)
1834                 goto out;
1835 
1836         dsl_pool_config_enter(dp, FTAG);
1837 
1838         err = dsl_dir_hold(dp, dcp->dc_name, FTAG, &dd, NULL);
1839         if (err != 0) {
1840                 dsl_pool_config_exit(dp, FTAG);
1841                 goto fail;
1842         }
1843 
1844         /* Don't visit hidden ($MOS & $ORIGIN) objsets. */
1845         if (dd->dd_myname[0] == '$') {
1846                 dsl_dir_rele(dd, FTAG);
1847                 dsl_pool_config_exit(dp, FTAG);
1848                 goto out;
1849         }
1850 
1851         thisobj = dd->dd_phys->dd_head_dataset_obj;
1852         attr = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
1853 
1854         /*
1855          * Iterate over all children.
1856          */
1857         if (dcp->dc_flags & DS_FIND_CHILDREN) {
1858                 for (zap_cursor_init(&zc, dp->dp_meta_objset,
1859                     dd->dd_phys->dd_child_dir_zapobj);
1860                     zap_cursor_retrieve(&zc, attr) == 0;
1861                     (void) zap_cursor_advance(&zc)) {
1862                         ASSERT3U(attr->za_integer_length, ==,
1863                             sizeof (uint64_t));
1864                         ASSERT3U(attr->za_num_integers, ==, 1);
1865 
1866                         child = kmem_asprintf("%s/%s", dcp->dc_name,
1867                             attr->za_name);
1868                         dsl_pool_config_exit(dp, FTAG);
1869                         child_dcp = kmem_alloc(sizeof(*child_dcp), KM_SLEEP);
1870                         *child_dcp = *dcp;
1871                         child_dcp->dc_name = child;
1872                         taskq_dispatch(dcp->dc_tq,
1873                             dmu_objset_find_parallel_impl, child_dcp, TQ_SLEEP);
1874                         dsl_pool_config_enter(dp, FTAG);
1875                 }
1876                 zap_cursor_fini(&zc);
1877         }
1878 
1879         dsl_dir_rele(dd, FTAG);
1880         kmem_free(attr, sizeof (zap_attribute_t));
1881         dsl_pool_config_exit(dp, FTAG);
1882 
1883         err = dcp->dc_func(dcp->dc_name, dcp->dc_arg);
1884 
1885 fail:
1886         if (err) {
1887                 mutex_enter(dcp->dc_error_lock);
1888                 /* only keep first error */
1889                 if (*dcp->dc_error == 0)
1890                         *dcp->dc_error = err;
1891                 mutex_exit(dcp->dc_error_lock);
1892         }
1893 
1894 out:
1895         strfree(dcp->dc_name);
1896         kmem_free(dcp, sizeof(*dcp));
1897 }
1898 
1899 int
1900 dmu_objset_find_parallel(char *name, int func(const char *, void *), void *arg,
1901     int flags)
1902 {
1903         spa_t *spa;
1904         int error;
1905         taskq_t *tq = NULL;
1906         int ntasks;
1907         dmu_objset_find_ctx_t *dcp;
1908         kmutex_t err_lock;
1909 
1910         error = spa_open(name, &spa, FTAG);
1911         if (error != 0)
1912                 return (error);
1913 
1914         ntasks = vdev_count_leaves(spa) * 4;
1915         tq = taskq_create("dmu_objset_find", ntasks, minclsyspri, ntasks,
1916             INT_MAX, 0);
1917         if (!tq) {
1918                 spa_close(spa, FTAG);
1919                 return (dmu_objset_find(name, func, arg, flags));
1920         }
1921 
1922         mutex_init(&err_lock, NULL, MUTEX_DEFAULT, NULL);
1923         dcp = kmem_alloc(sizeof(*dcp), KM_SLEEP);
1924         dcp->dc_tq = tq;
1925         dcp->dc_spa = spa;
1926         dcp->dc_name = strdup(name);
1927         dcp->dc_func = func;
1928         dcp->dc_arg = arg;
1929         dcp->dc_flags = flags;
1930         dcp->dc_error_lock = &err_lock;
1931         dcp->dc_error = &error;
1932         /* dcp and dc_name will be freed by task */
1933         taskq_dispatch(tq, dmu_objset_find_parallel_impl, dcp, TQ_SLEEP);
1934 
1935         taskq_wait(tq);
1936         taskq_destroy(tq);
1937         mutex_destroy(&err_lock);
1938 
1939         spa_close(spa, FTAG);
1940 
1941         return (error);
1942 }
1943 
1944 void
1945 dmu_objset_set_user(objset_t *os, void *user_ptr)
1946 {
1947         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1948         os->os_user_ptr = user_ptr;
1949 }
1950 
1951 void *
1952 dmu_objset_get_user(objset_t *os)
1953 {
1954         ASSERT(MUTEX_HELD(&os->os_user_ptr_lock));
1955         return (os->os_user_ptr);
1956 }
1957 
1958 /*
1959  * Determine name of filesystem, given name of snapshot.
1960  * buf must be at least MAXNAMELEN bytes
1961  */
1962 int
1963 dmu_fsname(const char *snapname, char *buf)
1964 {
1965         char *atp = strchr(snapname, '@');
1966         if (atp == NULL)
1967                 return (SET_ERROR(EINVAL));
1968         if (atp - snapname >= MAXNAMELEN)
1969                 return (SET_ERROR(ENAMETOOLONG));
1970         (void) strlcpy(buf, snapname, atp - snapname + 1);
1971         return (0);
1972 }