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 Martin Matuska. All rights reserved.
  25  * Copyright (c) 2014 Joyent, Inc. All rights reserved.
  26  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  27  * Copyright 2015 Nexenta Systems, Inc. All rights reserved.
  28  */
  29 
  30 #include <sys/dmu.h>
  31 #include <sys/dmu_objset.h>
  32 #include <sys/dmu_tx.h>
  33 #include <sys/dsl_dataset.h>
  34 #include <sys/dsl_dir.h>
  35 #include <sys/dsl_prop.h>
  36 #include <sys/dsl_synctask.h>
  37 #include <sys/dsl_deleg.h>
  38 #include <sys/dmu_impl.h>
  39 #include <sys/spa.h>
  40 #include <sys/metaslab.h>
  41 #include <sys/zap.h>
  42 #include <sys/zio.h>
  43 #include <sys/arc.h>
  44 #include <sys/sunddi.h>
  45 #include <sys/zfeature.h>
  46 #include <sys/policy.h>
  47 #include <sys/zfs_znode.h>
  48 #include "zfs_namecheck.h"
  49 #include "zfs_prop.h"
  50 
  51 /*
  52  * Filesystem and Snapshot Limits
  53  * ------------------------------
  54  *
  55  * These limits are used to restrict the number of filesystems and/or snapshots
  56  * that can be created at a given level in the tree or below. A typical
  57  * use-case is with a delegated dataset where the administrator wants to ensure
  58  * that a user within the zone is not creating too many additional filesystems
  59  * or snapshots, even though they're not exceeding their space quota.
  60  *
  61  * The filesystem and snapshot counts are stored as extensible properties. This
  62  * capability is controlled by a feature flag and must be enabled to be used.
  63  * Once enabled, the feature is not active until the first limit is set. At
  64  * that point, future operations to create/destroy filesystems or snapshots
  65  * will validate and update the counts.
  66  *
  67  * Because the count properties will not exist before the feature is active,
  68  * the counts are updated when a limit is first set on an uninitialized
  69  * dsl_dir node in the tree (The filesystem/snapshot count on a node includes
  70  * all of the nested filesystems/snapshots. Thus, a new leaf node has a
  71  * filesystem count of 0 and a snapshot count of 0. Non-existent filesystem and
  72  * snapshot count properties on a node indicate uninitialized counts on that
  73  * node.) When first setting a limit on an uninitialized node, the code starts
  74  * at the filesystem with the new limit and descends into all sub-filesystems
  75  * to add the count properties.
  76  *
  77  * In practice this is lightweight since a limit is typically set when the
  78  * filesystem is created and thus has no children. Once valid, changing the
  79  * limit value won't require a re-traversal since the counts are already valid.
  80  * When recursively fixing the counts, if a node with a limit is encountered
  81  * during the descent, the counts are known to be valid and there is no need to
  82  * descend into that filesystem's children. The counts on filesystems above the
  83  * one with the new limit will still be uninitialized, unless a limit is
  84  * eventually set on one of those filesystems. The counts are always recursively
  85  * updated when a limit is set on a dataset, unless there is already a limit.
  86  * When a new limit value is set on a filesystem with an existing limit, it is
  87  * possible for the new limit to be less than the current count at that level
  88  * since a user who can change the limit is also allowed to exceed the limit.
  89  *
  90  * Once the feature is active, then whenever a filesystem or snapshot is
  91  * created, the code recurses up the tree, validating the new count against the
  92  * limit at each initialized level. In practice, most levels will not have a
  93  * limit set. If there is a limit at any initialized level up the tree, the
  94  * check must pass or the creation will fail. Likewise, when a filesystem or
  95  * snapshot is destroyed, the counts are recursively adjusted all the way up
  96  * the initizized nodes in the tree. Renaming a filesystem into different point
  97  * in the tree will first validate, then update the counts on each branch up to
  98  * the common ancestor. A receive will also validate the counts and then update
  99  * them.
 100  *
 101  * An exception to the above behavior is that the limit is not enforced if the
 102  * user has permission to modify the limit. This is primarily so that
 103  * recursive snapshots in the global zone always work. We want to prevent a
 104  * denial-of-service in which a lower level delegated dataset could max out its
 105  * limit and thus block recursive snapshots from being taken in the global zone.
 106  * Because of this, it is possible for the snapshot count to be over the limit
 107  * and snapshots taken in the global zone could cause a lower level dataset to
 108  * hit or exceed its limit. The administrator taking the global zone recursive
 109  * snapshot should be aware of this side-effect and behave accordingly.
 110  * For consistency, the filesystem limit is also not enforced if the user can
 111  * modify the limit.
 112  *
 113  * The filesystem and snapshot limits are validated by dsl_fs_ss_limit_check()
 114  * and updated by dsl_fs_ss_count_adjust(). A new limit value is setup in
 115  * dsl_dir_activate_fs_ss_limit() and the counts are adjusted, if necessary, by
 116  * dsl_dir_init_fs_ss_count().
 117  *
 118  * There is a special case when we receive a filesystem that already exists. In
 119  * this case a temporary clone name of %X is created (see dmu_recv_begin). We
 120  * never update the filesystem counts for temporary clones.
 121  *
 122  * Likewise, we do not update the snapshot counts for temporary snapshots,
 123  * such as those created by zfs diff.
 124  */
 125 
 126 extern inline dsl_dir_phys_t *dsl_dir_phys(dsl_dir_t *dd);
 127 
 128 static uint64_t dsl_dir_space_towrite(dsl_dir_t *dd);
 129 
 130 static void
 131 dsl_dir_evict(void *dbu)
 132 {
 133         dsl_dir_t *dd = dbu;
 134         dsl_pool_t *dp = dd->dd_pool;
 135         int t;
 136 
 137         dd->dd_dbuf = NULL;
 138 
 139         for (t = 0; t < TXG_SIZE; t++) {
 140                 ASSERT(!txg_list_member(&dp->dp_dirty_dirs, dd, t));
 141                 ASSERT(dd->dd_tempreserved[t] == 0);
 142                 ASSERT(dd->dd_space_towrite[t] == 0);
 143         }
 144 
 145         if (dd->dd_parent)
 146                 dsl_dir_async_rele(dd->dd_parent, dd);
 147 
 148         spa_async_close(dd->dd_pool->dp_spa, dd);
 149 
 150         dsl_prop_fini(dd);
 151         mutex_destroy(&dd->dd_lock);
 152         kmem_free(dd, sizeof (dsl_dir_t));
 153 }
 154 
 155 int
 156 dsl_dir_hold_obj(dsl_pool_t *dp, uint64_t ddobj,
 157     const char *tail, void *tag, dsl_dir_t **ddp)
 158 {
 159         dmu_buf_t *dbuf;
 160         dsl_dir_t *dd;
 161         int err;
 162 
 163         ASSERT(dsl_pool_config_held(dp));
 164 
 165         err = dmu_bonus_hold(dp->dp_meta_objset, ddobj, tag, &dbuf);
 166         if (err != 0)
 167                 return (err);
 168         dd = dmu_buf_get_user(dbuf);
 169 #ifdef ZFS_DEBUG
 170         {
 171                 dmu_object_info_t doi;
 172                 dmu_object_info_from_db(dbuf, &doi);
 173                 ASSERT3U(doi.doi_bonus_type, ==, DMU_OT_DSL_DIR);
 174                 ASSERT3U(doi.doi_bonus_size, >=, sizeof (dsl_dir_phys_t));
 175         }
 176 #endif
 177         if (dd == NULL) {
 178                 dsl_dir_t *winner;
 179 
 180                 dd = kmem_zalloc(sizeof (dsl_dir_t), KM_SLEEP);
 181                 dd->dd_object = ddobj;
 182                 dd->dd_dbuf = dbuf;
 183                 dd->dd_pool = dp;
 184                 mutex_init(&dd->dd_lock, NULL, MUTEX_DEFAULT, NULL);
 185                 dsl_prop_init(dd);
 186 
 187                 dsl_dir_snap_cmtime_update(dd);
 188 
 189                 if (dsl_dir_phys(dd)->dd_parent_obj) {
 190                         err = dsl_dir_hold_obj(dp,
 191                             dsl_dir_phys(dd)->dd_parent_obj, NULL, dd,
 192                             &dd->dd_parent);
 193                         if (err != 0)
 194                                 goto errout;
 195                         if (tail) {
 196 #ifdef ZFS_DEBUG
 197                                 uint64_t foundobj;
 198 
 199                                 err = zap_lookup(dp->dp_meta_objset,
 200                                     dsl_dir_phys(dd->dd_parent)->
 201                                     dd_child_dir_zapobj, tail,
 202                                     sizeof (foundobj), 1, &foundobj);
 203                                 ASSERT(err || foundobj == ddobj);
 204 #endif
 205                                 (void) strcpy(dd->dd_myname, tail);
 206                         } else {
 207                                 err = zap_value_search(dp->dp_meta_objset,
 208                                     dsl_dir_phys(dd->dd_parent)->
 209                                     dd_child_dir_zapobj,
 210                                     ddobj, 0, dd->dd_myname);
 211                         }
 212                         if (err != 0)
 213                                 goto errout;
 214                 } else {
 215                         (void) strcpy(dd->dd_myname, spa_name(dp->dp_spa));
 216                 }
 217 
 218                 if (dsl_dir_is_clone(dd)) {
 219                         dmu_buf_t *origin_bonus;
 220                         dsl_dataset_phys_t *origin_phys;
 221 
 222                         /*
 223                          * We can't open the origin dataset, because
 224                          * that would require opening this dsl_dir.
 225                          * Just look at its phys directly instead.
 226                          */
 227                         err = dmu_bonus_hold(dp->dp_meta_objset,
 228                             dsl_dir_phys(dd)->dd_origin_obj, FTAG,
 229                             &origin_bonus);
 230                         if (err != 0)
 231                                 goto errout;
 232                         origin_phys = origin_bonus->db_data;
 233                         dd->dd_origin_txg =
 234                             origin_phys->ds_creation_txg;
 235                         dmu_buf_rele(origin_bonus, FTAG);
 236                 }
 237 
 238                 dmu_buf_init_user(&dd->dd_dbu, dsl_dir_evict, &dd->dd_dbuf);
 239                 winner = dmu_buf_set_user_ie(dbuf, &dd->dd_dbu);
 240                 if (winner != NULL) {
 241                         if (dd->dd_parent)
 242                                 dsl_dir_rele(dd->dd_parent, dd);
 243                         dsl_prop_fini(dd);
 244                         mutex_destroy(&dd->dd_lock);
 245                         kmem_free(dd, sizeof (dsl_dir_t));
 246                         dd = winner;
 247                 } else {
 248                         spa_open_ref(dp->dp_spa, dd);
 249                 }
 250         }
 251 
 252         /*
 253          * The dsl_dir_t has both open-to-close and instantiate-to-evict
 254          * holds on the spa.  We need the open-to-close holds because
 255          * otherwise the spa_refcnt wouldn't change when we open a
 256          * dir which the spa also has open, so we could incorrectly
 257          * think it was OK to unload/export/destroy the pool.  We need
 258          * the instantiate-to-evict hold because the dsl_dir_t has a
 259          * pointer to the dd_pool, which has a pointer to the spa_t.
 260          */
 261         spa_open_ref(dp->dp_spa, tag);
 262         ASSERT3P(dd->dd_pool, ==, dp);
 263         ASSERT3U(dd->dd_object, ==, ddobj);
 264         ASSERT3P(dd->dd_dbuf, ==, dbuf);
 265         *ddp = dd;
 266         return (0);
 267 
 268 errout:
 269         if (dd->dd_parent)
 270                 dsl_dir_rele(dd->dd_parent, dd);
 271         dsl_prop_fini(dd);
 272         mutex_destroy(&dd->dd_lock);
 273         kmem_free(dd, sizeof (dsl_dir_t));
 274         dmu_buf_rele(dbuf, tag);
 275         return (err);
 276 }
 277 
 278 void
 279 dsl_dir_rele(dsl_dir_t *dd, void *tag)
 280 {
 281         dprintf_dd(dd, "%s\n", "");
 282         spa_close(dd->dd_pool->dp_spa, tag);
 283         dmu_buf_rele(dd->dd_dbuf, tag);
 284 }
 285 
 286 /*
 287  * Remove a reference to the given dsl dir that is being asynchronously
 288  * released.  Async releases occur from a taskq performing eviction of
 289  * dsl datasets and dirs.  This process is identical to a normal release
 290  * with the exception of using the async API for releasing the reference on
 291  * the spa.
 292  */
 293 void
 294 dsl_dir_async_rele(dsl_dir_t *dd, void *tag)
 295 {
 296         dprintf_dd(dd, "%s\n", "");
 297         spa_async_close(dd->dd_pool->dp_spa, tag);
 298         dmu_buf_rele(dd->dd_dbuf, tag);
 299 }
 300 
 301 /* buf must be long enough (MAXNAMELEN + strlen(MOS_DIR_NAME) + 1 should do) */
 302 void
 303 dsl_dir_name(dsl_dir_t *dd, char *buf)
 304 {
 305         if (dd->dd_parent) {
 306                 dsl_dir_name(dd->dd_parent, buf);
 307                 (void) strcat(buf, "/");
 308         } else {
 309                 buf[0] = '\0';
 310         }
 311         if (!MUTEX_HELD(&dd->dd_lock)) {
 312                 /*
 313                  * recursive mutex so that we can use
 314                  * dprintf_dd() with dd_lock held
 315                  */
 316                 mutex_enter(&dd->dd_lock);
 317                 (void) strcat(buf, dd->dd_myname);
 318                 mutex_exit(&dd->dd_lock);
 319         } else {
 320                 (void) strcat(buf, dd->dd_myname);
 321         }
 322 }
 323 
 324 /* Calculate name length, avoiding all the strcat calls of dsl_dir_name */
 325 int
 326 dsl_dir_namelen(dsl_dir_t *dd)
 327 {
 328         int result = 0;
 329 
 330         if (dd->dd_parent) {
 331                 /* parent's name + 1 for the "/" */
 332                 result = dsl_dir_namelen(dd->dd_parent) + 1;
 333         }
 334 
 335         if (!MUTEX_HELD(&dd->dd_lock)) {
 336                 /* see dsl_dir_name */
 337                 mutex_enter(&dd->dd_lock);
 338                 result += strlen(dd->dd_myname);
 339                 mutex_exit(&dd->dd_lock);
 340         } else {
 341                 result += strlen(dd->dd_myname);
 342         }
 343 
 344         return (result);
 345 }
 346 
 347 static int
 348 getcomponent(const char *path, char *component, const char **nextp)
 349 {
 350         char *p;
 351 
 352         if ((path == NULL) || (path[0] == '\0'))
 353                 return (SET_ERROR(ENOENT));
 354         /* This would be a good place to reserve some namespace... */
 355         p = strpbrk(path, "/@");
 356         if (p && (p[1] == '/' || p[1] == '@')) {
 357                 /* two separators in a row */
 358                 return (SET_ERROR(EINVAL));
 359         }
 360         if (p == NULL || p == path) {
 361                 /*
 362                  * if the first thing is an @ or /, it had better be an
 363                  * @ and it had better not have any more ats or slashes,
 364                  * and it had better have something after the @.
 365                  */
 366                 if (p != NULL &&
 367                     (p[0] != '@' || strpbrk(path+1, "/@") || p[1] == '\0'))
 368                         return (SET_ERROR(EINVAL));
 369                 if (strlen(path) >= MAXNAMELEN)
 370                         return (SET_ERROR(ENAMETOOLONG));
 371                 (void) strcpy(component, path);
 372                 p = NULL;
 373         } else if (p[0] == '/') {
 374                 if (p - path >= MAXNAMELEN)
 375                         return (SET_ERROR(ENAMETOOLONG));
 376                 (void) strncpy(component, path, p - path);
 377                 component[p - path] = '\0';
 378                 p++;
 379         } else if (p[0] == '@') {
 380                 /*
 381                  * if the next separator is an @, there better not be
 382                  * any more slashes.
 383                  */
 384                 if (strchr(path, '/'))
 385                         return (SET_ERROR(EINVAL));
 386                 if (p - path >= MAXNAMELEN)
 387                         return (SET_ERROR(ENAMETOOLONG));
 388                 (void) strncpy(component, path, p - path);
 389                 component[p - path] = '\0';
 390         } else {
 391                 panic("invalid p=%p", (void *)p);
 392         }
 393         *nextp = p;
 394         return (0);
 395 }
 396 
 397 /*
 398  * Return the dsl_dir_t, and possibly the last component which couldn't
 399  * be found in *tail.  The name must be in the specified dsl_pool_t.  This
 400  * thread must hold the dp_config_rwlock for the pool.  Returns NULL if the
 401  * path is bogus, or if tail==NULL and we couldn't parse the whole name.
 402  * (*tail)[0] == '@' means that the last component is a snapshot.
 403  */
 404 int
 405 dsl_dir_hold(dsl_pool_t *dp, const char *name, void *tag,
 406     dsl_dir_t **ddp, const char **tailp)
 407 {
 408         char buf[MAXNAMELEN];
 409         const char *spaname, *next, *nextnext = NULL;
 410         int err;
 411         dsl_dir_t *dd;
 412         uint64_t ddobj;
 413 
 414         err = getcomponent(name, buf, &next);
 415         if (err != 0)
 416                 return (err);
 417 
 418         /* Make sure the name is in the specified pool. */
 419         spaname = spa_name(dp->dp_spa);
 420         if (strcmp(buf, spaname) != 0)
 421                 return (SET_ERROR(EXDEV));
 422 
 423         ASSERT(dsl_pool_config_held(dp));
 424 
 425         err = dsl_dir_hold_obj(dp, dp->dp_root_dir_obj, NULL, tag, &dd);
 426         if (err != 0) {
 427                 return (err);
 428         }
 429 
 430         while (next != NULL) {
 431                 dsl_dir_t *child_dd;
 432                 err = getcomponent(next, buf, &nextnext);
 433                 if (err != 0)
 434                         break;
 435                 ASSERT(next[0] != '\0');
 436                 if (next[0] == '@')
 437                         break;
 438                 dprintf("looking up %s in obj%lld\n",
 439                     buf, dsl_dir_phys(dd)->dd_child_dir_zapobj);
 440 
 441                 err = zap_lookup(dp->dp_meta_objset,
 442                     dsl_dir_phys(dd)->dd_child_dir_zapobj,
 443                     buf, sizeof (ddobj), 1, &ddobj);
 444                 if (err != 0) {
 445                         if (err == ENOENT)
 446                                 err = 0;
 447                         break;
 448                 }
 449 
 450                 err = dsl_dir_hold_obj(dp, ddobj, buf, tag, &child_dd);
 451                 if (err != 0)
 452                         break;
 453                 dsl_dir_rele(dd, tag);
 454                 dd = child_dd;
 455                 next = nextnext;
 456         }
 457 
 458         if (err != 0) {
 459                 dsl_dir_rele(dd, tag);
 460                 return (err);
 461         }
 462 
 463         /*
 464          * It's an error if there's more than one component left, or
 465          * tailp==NULL and there's any component left.
 466          */
 467         if (next != NULL &&
 468             (tailp == NULL || (nextnext && nextnext[0] != '\0'))) {
 469                 /* bad path name */
 470                 dsl_dir_rele(dd, tag);
 471                 dprintf("next=%p (%s) tail=%p\n", next, next?next:"", tailp);
 472                 err = SET_ERROR(ENOENT);
 473         }
 474         if (tailp != NULL)
 475                 *tailp = next;
 476         *ddp = dd;
 477         return (err);
 478 }
 479 
 480 /*
 481  * If the counts are already initialized for this filesystem and its
 482  * descendants then do nothing, otherwise initialize the counts.
 483  *
 484  * The counts on this filesystem, and those below, may be uninitialized due to
 485  * either the use of a pre-existing pool which did not support the
 486  * filesystem/snapshot limit feature, or one in which the feature had not yet
 487  * been enabled.
 488  *
 489  * Recursively descend the filesystem tree and update the filesystem/snapshot
 490  * counts on each filesystem below, then update the cumulative count on the
 491  * current filesystem. If the filesystem already has a count set on it,
 492  * then we know that its counts, and the counts on the filesystems below it,
 493  * are already correct, so we don't have to update this filesystem.
 494  */
 495 static void
 496 dsl_dir_init_fs_ss_count(dsl_dir_t *dd, dmu_tx_t *tx)
 497 {
 498         uint64_t my_fs_cnt = 0;
 499         uint64_t my_ss_cnt = 0;
 500         dsl_pool_t *dp = dd->dd_pool;
 501         objset_t *os = dp->dp_meta_objset;
 502         zap_cursor_t *zc;
 503         zap_attribute_t *za;
 504         dsl_dataset_t *ds;
 505 
 506         ASSERT(spa_feature_is_active(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT));
 507         ASSERT(dsl_pool_config_held(dp));
 508         ASSERT(dmu_tx_is_syncing(tx));
 509 
 510         dsl_dir_zapify(dd, tx);
 511 
 512         /*
 513          * If the filesystem count has already been initialized then we
 514          * don't need to recurse down any further.
 515          */
 516         if (zap_contains(os, dd->dd_object, DD_FIELD_FILESYSTEM_COUNT) == 0)
 517                 return;
 518 
 519         zc = kmem_alloc(sizeof (zap_cursor_t), KM_SLEEP);
 520         za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
 521 
 522         /* Iterate my child dirs */
 523         for (zap_cursor_init(zc, os, dsl_dir_phys(dd)->dd_child_dir_zapobj);
 524             zap_cursor_retrieve(zc, za) == 0; zap_cursor_advance(zc)) {
 525                 dsl_dir_t *chld_dd;
 526                 uint64_t count;
 527 
 528                 VERIFY0(dsl_dir_hold_obj(dp, za->za_first_integer, NULL, FTAG,
 529                     &chld_dd));
 530 
 531                 /*
 532                  * Ignore hidden ($FREE, $MOS & $ORIGIN) objsets and
 533                  * temporary datasets.
 534                  */
 535                 if (chld_dd->dd_myname[0] == '$' ||
 536                     chld_dd->dd_myname[0] == '%') {
 537                         dsl_dir_rele(chld_dd, FTAG);
 538                         continue;
 539                 }
 540 
 541                 my_fs_cnt++;    /* count this child */
 542 
 543                 dsl_dir_init_fs_ss_count(chld_dd, tx);
 544 
 545                 VERIFY0(zap_lookup(os, chld_dd->dd_object,
 546                     DD_FIELD_FILESYSTEM_COUNT, sizeof (count), 1, &count));
 547                 my_fs_cnt += count;
 548                 VERIFY0(zap_lookup(os, chld_dd->dd_object,
 549                     DD_FIELD_SNAPSHOT_COUNT, sizeof (count), 1, &count));
 550                 my_ss_cnt += count;
 551 
 552                 dsl_dir_rele(chld_dd, FTAG);
 553         }
 554         zap_cursor_fini(zc);
 555         /* Count my snapshots (we counted children's snapshots above) */
 556         VERIFY0(dsl_dataset_hold_obj(dd->dd_pool,
 557             dsl_dir_phys(dd)->dd_head_dataset_obj, FTAG, &ds));
 558 
 559         for (zap_cursor_init(zc, os, dsl_dataset_phys(ds)->ds_snapnames_zapobj);
 560             zap_cursor_retrieve(zc, za) == 0;
 561             zap_cursor_advance(zc)) {
 562                 /* Don't count temporary snapshots */
 563                 if (za->za_name[0] != '%')
 564                         my_ss_cnt++;
 565         }
 566         zap_cursor_fini(zc);
 567 
 568         dsl_dataset_rele(ds, FTAG);
 569 
 570         kmem_free(zc, sizeof (zap_cursor_t));
 571         kmem_free(za, sizeof (zap_attribute_t));
 572 
 573         /* we're in a sync task, update counts */
 574         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 575         VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_FILESYSTEM_COUNT,
 576             sizeof (my_fs_cnt), 1, &my_fs_cnt, tx));
 577         VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_SNAPSHOT_COUNT,
 578             sizeof (my_ss_cnt), 1, &my_ss_cnt, tx));
 579 }
 580 
 581 static int
 582 dsl_dir_actv_fs_ss_limit_check(void *arg, dmu_tx_t *tx)
 583 {
 584         char *ddname = (char *)arg;
 585         dsl_pool_t *dp = dmu_tx_pool(tx);
 586         dsl_dataset_t *ds;
 587         dsl_dir_t *dd;
 588         int error;
 589 
 590         error = dsl_dataset_hold(dp, ddname, FTAG, &ds);
 591         if (error != 0)
 592                 return (error);
 593 
 594         if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT)) {
 595                 dsl_dataset_rele(ds, FTAG);
 596                 return (SET_ERROR(ENOTSUP));
 597         }
 598 
 599         dd = ds->ds_dir;
 600         if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT) &&
 601             dsl_dir_is_zapified(dd) &&
 602             zap_contains(dp->dp_meta_objset, dd->dd_object,
 603             DD_FIELD_FILESYSTEM_COUNT) == 0) {
 604                 dsl_dataset_rele(ds, FTAG);
 605                 return (SET_ERROR(EALREADY));
 606         }
 607 
 608         dsl_dataset_rele(ds, FTAG);
 609         return (0);
 610 }
 611 
 612 static void
 613 dsl_dir_actv_fs_ss_limit_sync(void *arg, dmu_tx_t *tx)
 614 {
 615         char *ddname = (char *)arg;
 616         dsl_pool_t *dp = dmu_tx_pool(tx);
 617         dsl_dataset_t *ds;
 618         spa_t *spa;
 619 
 620         VERIFY0(dsl_dataset_hold(dp, ddname, FTAG, &ds));
 621 
 622         spa = dsl_dataset_get_spa(ds);
 623 
 624         if (!spa_feature_is_active(spa, SPA_FEATURE_FS_SS_LIMIT)) {
 625                 /*
 626                  * Since the feature was not active and we're now setting a
 627                  * limit, increment the feature-active counter so that the
 628                  * feature becomes active for the first time.
 629                  *
 630                  * We are already in a sync task so we can update the MOS.
 631                  */
 632                 spa_feature_incr(spa, SPA_FEATURE_FS_SS_LIMIT, tx);
 633         }
 634 
 635         /*
 636          * Since we are now setting a non-UINT64_MAX limit on the filesystem,
 637          * we need to ensure the counts are correct. Descend down the tree from
 638          * this point and update all of the counts to be accurate.
 639          */
 640         dsl_dir_init_fs_ss_count(ds->ds_dir, tx);
 641 
 642         dsl_dataset_rele(ds, FTAG);
 643 }
 644 
 645 /*
 646  * Make sure the feature is enabled and activate it if necessary.
 647  * Since we're setting a limit, ensure the on-disk counts are valid.
 648  * This is only called by the ioctl path when setting a limit value.
 649  *
 650  * We do not need to validate the new limit, since users who can change the
 651  * limit are also allowed to exceed the limit.
 652  */
 653 int
 654 dsl_dir_activate_fs_ss_limit(const char *ddname)
 655 {
 656         int error;
 657 
 658         error = dsl_sync_task(ddname, dsl_dir_actv_fs_ss_limit_check,
 659             dsl_dir_actv_fs_ss_limit_sync, (void *)ddname, 0,
 660             ZFS_SPACE_CHECK_RESERVED);
 661 
 662         if (error == EALREADY)
 663                 error = 0;
 664 
 665         return (error);
 666 }
 667 
 668 /*
 669  * Used to determine if the filesystem_limit or snapshot_limit should be
 670  * enforced. We allow the limit to be exceeded if the user has permission to
 671  * write the property value. We pass in the creds that we got in the open
 672  * context since we will always be the GZ root in syncing context. We also have
 673  * to handle the case where we are allowed to change the limit on the current
 674  * dataset, but there may be another limit in the tree above.
 675  *
 676  * We can never modify these two properties within a non-global zone. In
 677  * addition, the other checks are modeled on zfs_secpolicy_write_perms. We
 678  * can't use that function since we are already holding the dp_config_rwlock.
 679  * In addition, we already have the dd and dealing with snapshots is simplified
 680  * in this code.
 681  */
 682 
 683 typedef enum {
 684         ENFORCE_ALWAYS,
 685         ENFORCE_NEVER,
 686         ENFORCE_ABOVE
 687 } enforce_res_t;
 688 
 689 static enforce_res_t
 690 dsl_enforce_ds_ss_limits(dsl_dir_t *dd, zfs_prop_t prop, cred_t *cr)
 691 {
 692         enforce_res_t enforce = ENFORCE_ALWAYS;
 693         uint64_t obj;
 694         dsl_dataset_t *ds;
 695         uint64_t zoned;
 696 
 697         ASSERT(prop == ZFS_PROP_FILESYSTEM_LIMIT ||
 698             prop == ZFS_PROP_SNAPSHOT_LIMIT);
 699 
 700 #ifdef _KERNEL
 701         if (crgetzoneid(cr) != GLOBAL_ZONEID)
 702                 return (ENFORCE_ALWAYS);
 703 
 704         if (secpolicy_zfs(cr) == 0)
 705                 return (ENFORCE_NEVER);
 706 #endif
 707 
 708         if ((obj = dsl_dir_phys(dd)->dd_head_dataset_obj) == 0)
 709                 return (ENFORCE_ALWAYS);
 710 
 711         ASSERT(dsl_pool_config_held(dd->dd_pool));
 712 
 713         if (dsl_dataset_hold_obj(dd->dd_pool, obj, FTAG, &ds) != 0)
 714                 return (ENFORCE_ALWAYS);
 715 
 716         if (dsl_prop_get_ds(ds, "zoned", 8, 1, &zoned, NULL) || zoned) {
 717                 /* Only root can access zoned fs's from the GZ */
 718                 enforce = ENFORCE_ALWAYS;
 719         } else {
 720                 if (dsl_deleg_access_impl(ds, zfs_prop_to_name(prop), cr) == 0)
 721                         enforce = ENFORCE_ABOVE;
 722         }
 723 
 724         dsl_dataset_rele(ds, FTAG);
 725         return (enforce);
 726 }
 727 
 728 /*
 729  * Check if adding additional child filesystem(s) would exceed any filesystem
 730  * limits or adding additional snapshot(s) would exceed any snapshot limits.
 731  * The prop argument indicates which limit to check.
 732  *
 733  * Note that all filesystem limits up to the root (or the highest
 734  * initialized) filesystem or the given ancestor must be satisfied.
 735  */
 736 int
 737 dsl_fs_ss_limit_check(dsl_dir_t *dd, uint64_t delta, zfs_prop_t prop,
 738     dsl_dir_t *ancestor, cred_t *cr)
 739 {
 740         objset_t *os = dd->dd_pool->dp_meta_objset;
 741         uint64_t limit, count;
 742         char *count_prop;
 743         enforce_res_t enforce;
 744         int err = 0;
 745 
 746         ASSERT(dsl_pool_config_held(dd->dd_pool));
 747         ASSERT(prop == ZFS_PROP_FILESYSTEM_LIMIT ||
 748             prop == ZFS_PROP_SNAPSHOT_LIMIT);
 749 
 750         /*
 751          * If we're allowed to change the limit, don't enforce the limit
 752          * e.g. this can happen if a snapshot is taken by an administrative
 753          * user in the global zone (i.e. a recursive snapshot by root).
 754          * However, we must handle the case of delegated permissions where we
 755          * are allowed to change the limit on the current dataset, but there
 756          * is another limit in the tree above.
 757          */
 758         enforce = dsl_enforce_ds_ss_limits(dd, prop, cr);
 759         if (enforce == ENFORCE_NEVER)
 760                 return (0);
 761 
 762         /*
 763          * e.g. if renaming a dataset with no snapshots, count adjustment
 764          * is 0.
 765          */
 766         if (delta == 0)
 767                 return (0);
 768 
 769         if (prop == ZFS_PROP_SNAPSHOT_LIMIT) {
 770                 /*
 771                  * We don't enforce the limit for temporary snapshots. This is
 772                  * indicated by a NULL cred_t argument.
 773                  */
 774                 if (cr == NULL)
 775                         return (0);
 776 
 777                 count_prop = DD_FIELD_SNAPSHOT_COUNT;
 778         } else {
 779                 count_prop = DD_FIELD_FILESYSTEM_COUNT;
 780         }
 781 
 782         /*
 783          * If an ancestor has been provided, stop checking the limit once we
 784          * hit that dir. We need this during rename so that we don't overcount
 785          * the check once we recurse up to the common ancestor.
 786          */
 787         if (ancestor == dd)
 788                 return (0);
 789 
 790         /*
 791          * If we hit an uninitialized node while recursing up the tree, we can
 792          * stop since we know there is no limit here (or above). The counts are
 793          * not valid on this node and we know we won't touch this node's counts.
 794          */
 795         if (!dsl_dir_is_zapified(dd) || zap_lookup(os, dd->dd_object,
 796             count_prop, sizeof (count), 1, &count) == ENOENT)
 797                 return (0);
 798 
 799         err = dsl_prop_get_dd(dd, zfs_prop_to_name(prop), 8, 1, &limit, NULL,
 800             B_FALSE);
 801         if (err != 0)
 802                 return (err);
 803 
 804         /* Is there a limit which we've hit? */
 805         if (enforce == ENFORCE_ALWAYS && (count + delta) > limit)
 806                 return (SET_ERROR(EDQUOT));
 807 
 808         if (dd->dd_parent != NULL)
 809                 err = dsl_fs_ss_limit_check(dd->dd_parent, delta, prop,
 810                     ancestor, cr);
 811 
 812         return (err);
 813 }
 814 
 815 /*
 816  * Adjust the filesystem or snapshot count for the specified dsl_dir_t and all
 817  * parents. When a new filesystem/snapshot is created, increment the count on
 818  * all parents, and when a filesystem/snapshot is destroyed, decrement the
 819  * count.
 820  */
 821 void
 822 dsl_fs_ss_count_adjust(dsl_dir_t *dd, int64_t delta, const char *prop,
 823     dmu_tx_t *tx)
 824 {
 825         int err;
 826         objset_t *os = dd->dd_pool->dp_meta_objset;
 827         uint64_t count;
 828 
 829         ASSERT(dsl_pool_config_held(dd->dd_pool));
 830         ASSERT(dmu_tx_is_syncing(tx));
 831         ASSERT(strcmp(prop, DD_FIELD_FILESYSTEM_COUNT) == 0 ||
 832             strcmp(prop, DD_FIELD_SNAPSHOT_COUNT) == 0);
 833 
 834         /*
 835          * When we receive an incremental stream into a filesystem that already
 836          * exists, a temporary clone is created.  We don't count this temporary
 837          * clone, whose name begins with a '%'. We also ignore hidden ($FREE,
 838          * $MOS & $ORIGIN) objsets.
 839          */
 840         if ((dd->dd_myname[0] == '%' || dd->dd_myname[0] == '$') &&
 841             strcmp(prop, DD_FIELD_FILESYSTEM_COUNT) == 0)
 842                 return;
 843 
 844         /*
 845          * e.g. if renaming a dataset with no snapshots, count adjustment is 0
 846          */
 847         if (delta == 0)
 848                 return;
 849 
 850         /*
 851          * If we hit an uninitialized node while recursing up the tree, we can
 852          * stop since we know the counts are not valid on this node and we
 853          * know we shouldn't touch this node's counts. An uninitialized count
 854          * on the node indicates that either the feature has not yet been
 855          * activated or there are no limits on this part of the tree.
 856          */
 857         if (!dsl_dir_is_zapified(dd) || (err = zap_lookup(os, dd->dd_object,
 858             prop, sizeof (count), 1, &count)) == ENOENT)
 859                 return;
 860         VERIFY0(err);
 861 
 862         count += delta;
 863         /* Use a signed verify to make sure we're not neg. */
 864         VERIFY3S(count, >=, 0);
 865 
 866         VERIFY0(zap_update(os, dd->dd_object, prop, sizeof (count), 1, &count,
 867             tx));
 868 
 869         /* Roll up this additional count into our ancestors */
 870         if (dd->dd_parent != NULL)
 871                 dsl_fs_ss_count_adjust(dd->dd_parent, delta, prop, tx);
 872 }
 873 
 874 uint64_t
 875 dsl_dir_create_sync(dsl_pool_t *dp, dsl_dir_t *pds, const char *name,
 876     dmu_tx_t *tx)
 877 {
 878         objset_t *mos = dp->dp_meta_objset;
 879         uint64_t ddobj;
 880         dsl_dir_phys_t *ddphys;
 881         dmu_buf_t *dbuf;
 882 
 883         ddobj = dmu_object_alloc(mos, DMU_OT_DSL_DIR, 0,
 884             DMU_OT_DSL_DIR, sizeof (dsl_dir_phys_t), tx);
 885         if (pds) {
 886                 VERIFY(0 == zap_add(mos, dsl_dir_phys(pds)->dd_child_dir_zapobj,
 887                     name, sizeof (uint64_t), 1, &ddobj, tx));
 888         } else {
 889                 /* it's the root dir */
 890                 VERIFY(0 == zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
 891                     DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, &ddobj, tx));
 892         }
 893         VERIFY(0 == dmu_bonus_hold(mos, ddobj, FTAG, &dbuf));
 894         dmu_buf_will_dirty(dbuf, tx);
 895         ddphys = dbuf->db_data;
 896 
 897         ddphys->dd_creation_time = gethrestime_sec();
 898         if (pds) {
 899                 ddphys->dd_parent_obj = pds->dd_object;
 900 
 901                 /* update the filesystem counts */
 902                 dsl_fs_ss_count_adjust(pds, 1, DD_FIELD_FILESYSTEM_COUNT, tx);
 903         }
 904         ddphys->dd_props_zapobj = zap_create(mos,
 905             DMU_OT_DSL_PROPS, DMU_OT_NONE, 0, tx);
 906         ddphys->dd_child_dir_zapobj = zap_create(mos,
 907             DMU_OT_DSL_DIR_CHILD_MAP, DMU_OT_NONE, 0, tx);
 908         if (spa_version(dp->dp_spa) >= SPA_VERSION_USED_BREAKDOWN)
 909                 ddphys->dd_flags |= DD_FLAG_USED_BREAKDOWN;
 910         dmu_buf_rele(dbuf, FTAG);
 911 
 912         return (ddobj);
 913 }
 914 
 915 boolean_t
 916 dsl_dir_is_clone(dsl_dir_t *dd)
 917 {
 918         return (dsl_dir_phys(dd)->dd_origin_obj &&
 919             (dd->dd_pool->dp_origin_snap == NULL ||
 920             dsl_dir_phys(dd)->dd_origin_obj !=
 921             dd->dd_pool->dp_origin_snap->ds_object));
 922 }
 923 
 924 void
 925 dsl_dir_stats(dsl_dir_t *dd, nvlist_t *nv)
 926 {
 927         mutex_enter(&dd->dd_lock);
 928         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
 929             dsl_dir_phys(dd)->dd_used_bytes);
 930         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_QUOTA,
 931             dsl_dir_phys(dd)->dd_quota);
 932         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_RESERVATION,
 933             dsl_dir_phys(dd)->dd_reserved);
 934         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
 935             dsl_dir_phys(dd)->dd_compressed_bytes == 0 ? 100 :
 936             (dsl_dir_phys(dd)->dd_uncompressed_bytes * 100 /
 937             dsl_dir_phys(dd)->dd_compressed_bytes));
 938         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALUSED,
 939             dsl_dir_phys(dd)->dd_uncompressed_bytes);
 940         if (dsl_dir_phys(dd)->dd_flags & DD_FLAG_USED_BREAKDOWN) {
 941                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDSNAP,
 942                     dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_SNAP]);
 943                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDDS,
 944                     dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_HEAD]);
 945                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDREFRESERV,
 946                     dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_REFRSRV]);
 947                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDCHILD,
 948                     dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_CHILD] +
 949                     dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_CHILD_RSRV]);
 950         }
 951         mutex_exit(&dd->dd_lock);
 952 
 953         if (dsl_dir_is_zapified(dd)) {
 954                 uint64_t count;
 955                 objset_t *os = dd->dd_pool->dp_meta_objset;
 956 
 957                 if (zap_lookup(os, dd->dd_object, DD_FIELD_FILESYSTEM_COUNT,
 958                     sizeof (count), 1, &count) == 0) {
 959                         dsl_prop_nvlist_add_uint64(nv,
 960                             ZFS_PROP_FILESYSTEM_COUNT, count);
 961                 }
 962                 if (zap_lookup(os, dd->dd_object, DD_FIELD_SNAPSHOT_COUNT,
 963                     sizeof (count), 1, &count) == 0) {
 964                         dsl_prop_nvlist_add_uint64(nv,
 965                             ZFS_PROP_SNAPSHOT_COUNT, count);
 966                 }
 967         }
 968 
 969         if (dsl_dir_is_clone(dd)) {
 970                 dsl_dataset_t *ds;
 971                 char buf[MAXNAMELEN];
 972 
 973                 VERIFY0(dsl_dataset_hold_obj(dd->dd_pool,
 974                     dsl_dir_phys(dd)->dd_origin_obj, FTAG, &ds));
 975                 dsl_dataset_name(ds, buf);
 976                 dsl_dataset_rele(ds, FTAG);
 977                 dsl_prop_nvlist_add_string(nv, ZFS_PROP_ORIGIN, buf);
 978         }
 979 }
 980 
 981 void
 982 dsl_dir_dirty(dsl_dir_t *dd, dmu_tx_t *tx)
 983 {
 984         dsl_pool_t *dp = dd->dd_pool;
 985 
 986         ASSERT(dsl_dir_phys(dd));
 987 
 988         if (txg_list_add(&dp->dp_dirty_dirs, dd, tx->tx_txg)) {
 989                 /* up the hold count until we can be written out */
 990                 dmu_buf_add_ref(dd->dd_dbuf, dd);
 991         }
 992 }
 993 
 994 static int64_t
 995 parent_delta(dsl_dir_t *dd, uint64_t used, int64_t delta)
 996 {
 997         uint64_t old_accounted = MAX(used, dsl_dir_phys(dd)->dd_reserved);
 998         uint64_t new_accounted =
 999             MAX(used + delta, dsl_dir_phys(dd)->dd_reserved);
1000         return (new_accounted - old_accounted);
1001 }
1002 
1003 void
1004 dsl_dir_sync(dsl_dir_t *dd, dmu_tx_t *tx)
1005 {
1006         ASSERT(dmu_tx_is_syncing(tx));
1007 
1008         mutex_enter(&dd->dd_lock);
1009         ASSERT0(dd->dd_tempreserved[tx->tx_txg&TXG_MASK]);
1010         dprintf_dd(dd, "txg=%llu towrite=%lluK\n", tx->tx_txg,
1011             dd->dd_space_towrite[tx->tx_txg&TXG_MASK] / 1024);
1012         dd->dd_space_towrite[tx->tx_txg&TXG_MASK] = 0;
1013         mutex_exit(&dd->dd_lock);
1014 
1015         /* release the hold from dsl_dir_dirty */
1016         dmu_buf_rele(dd->dd_dbuf, dd);
1017 }
1018 
1019 static uint64_t
1020 dsl_dir_space_towrite(dsl_dir_t *dd)
1021 {
1022         uint64_t space = 0;
1023         int i;
1024 
1025         ASSERT(MUTEX_HELD(&dd->dd_lock));
1026 
1027         for (i = 0; i < TXG_SIZE; i++) {
1028                 space += dd->dd_space_towrite[i&TXG_MASK];
1029                 ASSERT3U(dd->dd_space_towrite[i&TXG_MASK], >=, 0);
1030         }
1031         return (space);
1032 }
1033 
1034 /*
1035  * How much space would dd have available if ancestor had delta applied
1036  * to it?  If ondiskonly is set, we're only interested in what's
1037  * on-disk, not estimated pending changes.
1038  */
1039 uint64_t
1040 dsl_dir_space_available(dsl_dir_t *dd,
1041     dsl_dir_t *ancestor, int64_t delta, int ondiskonly)
1042 {
1043         uint64_t parentspace, myspace, quota, used;
1044 
1045         /*
1046          * If there are no restrictions otherwise, assume we have
1047          * unlimited space available.
1048          */
1049         quota = UINT64_MAX;
1050         parentspace = UINT64_MAX;
1051 
1052         if (dd->dd_parent != NULL) {
1053                 parentspace = dsl_dir_space_available(dd->dd_parent,
1054                     ancestor, delta, ondiskonly);
1055         }
1056 
1057         mutex_enter(&dd->dd_lock);
1058         if (dsl_dir_phys(dd)->dd_quota != 0)
1059                 quota = dsl_dir_phys(dd)->dd_quota;
1060         used = dsl_dir_phys(dd)->dd_used_bytes;
1061         if (!ondiskonly)
1062                 used += dsl_dir_space_towrite(dd);
1063 
1064         if (dd->dd_parent == NULL) {
1065                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, FALSE);
1066                 quota = MIN(quota, poolsize);
1067         }
1068 
1069         if (dsl_dir_phys(dd)->dd_reserved > used && parentspace != UINT64_MAX) {
1070                 /*
1071                  * We have some space reserved, in addition to what our
1072                  * parent gave us.
1073                  */
1074                 parentspace += dsl_dir_phys(dd)->dd_reserved - used;
1075         }
1076 
1077         if (dd == ancestor) {
1078                 ASSERT(delta <= 0);
1079                 ASSERT(used >= -delta);
1080                 used += delta;
1081                 if (parentspace != UINT64_MAX)
1082                         parentspace -= delta;
1083         }
1084 
1085         if (used > quota) {
1086                 /* over quota */
1087                 myspace = 0;
1088         } else {
1089                 /*
1090                  * the lesser of the space provided by our parent and
1091                  * the space left in our quota
1092                  */
1093                 myspace = MIN(parentspace, quota - used);
1094         }
1095 
1096         mutex_exit(&dd->dd_lock);
1097 
1098         return (myspace);
1099 }
1100 
1101 struct tempreserve {
1102         list_node_t tr_node;
1103         dsl_dir_t *tr_ds;
1104         uint64_t tr_size;
1105 };
1106 
1107 static int
1108 dsl_dir_tempreserve_impl(dsl_dir_t *dd, uint64_t asize, boolean_t netfree,
1109     boolean_t ignorequota, boolean_t checkrefquota, list_t *tr_list,
1110     dmu_tx_t *tx, boolean_t first)
1111 {
1112         uint64_t txg = tx->tx_txg;
1113         uint64_t est_inflight, used_on_disk, quota, parent_rsrv;
1114         uint64_t deferred = 0;
1115         struct tempreserve *tr;
1116         int retval = EDQUOT;
1117         int txgidx = txg & TXG_MASK;
1118         int i;
1119         uint64_t ref_rsrv = 0;
1120 
1121         ASSERT3U(txg, !=, 0);
1122         ASSERT3S(asize, >, 0);
1123 
1124         mutex_enter(&dd->dd_lock);
1125 
1126         /*
1127          * Check against the dsl_dir's quota.  We don't add in the delta
1128          * when checking for over-quota because they get one free hit.
1129          */
1130         est_inflight = dsl_dir_space_towrite(dd);
1131         for (i = 0; i < TXG_SIZE; i++)
1132                 est_inflight += dd->dd_tempreserved[i];
1133         used_on_disk = dsl_dir_phys(dd)->dd_used_bytes;
1134 
1135         /*
1136          * On the first iteration, fetch the dataset's used-on-disk and
1137          * refreservation values. Also, if checkrefquota is set, test if
1138          * allocating this space would exceed the dataset's refquota.
1139          */
1140         if (first && tx->tx_objset) {
1141                 int error;
1142                 dsl_dataset_t *ds = tx->tx_objset->os_dsl_dataset;
1143 
1144                 error = dsl_dataset_check_quota(ds, checkrefquota,
1145                     asize, est_inflight, &used_on_disk, &ref_rsrv);
1146                 if (error) {
1147                         mutex_exit(&dd->dd_lock);
1148                         return (error);
1149                 }
1150         }
1151 
1152         /*
1153          * If this transaction will result in a net free of space,
1154          * we want to let it through.
1155          */
1156         if (ignorequota || netfree || dsl_dir_phys(dd)->dd_quota == 0)
1157                 quota = UINT64_MAX;
1158         else
1159                 quota = dsl_dir_phys(dd)->dd_quota;
1160 
1161         /*
1162          * Adjust the quota against the actual pool size at the root
1163          * minus any outstanding deferred frees.
1164          * To ensure that it's possible to remove files from a full
1165          * pool without inducing transient overcommits, we throttle
1166          * netfree transactions against a quota that is slightly larger,
1167          * but still within the pool's allocation slop.  In cases where
1168          * we're very close to full, this will allow a steady trickle of
1169          * removes to get through.
1170          */
1171         if (dd->dd_parent == NULL) {
1172                 spa_t *spa = dd->dd_pool->dp_spa;
1173                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, netfree);
1174                 deferred = metaslab_class_get_deferred(spa_normal_class(spa));
1175                 if (poolsize - deferred < quota) {
1176                         quota = poolsize - deferred;
1177                         retval = ENOSPC;
1178                 }
1179         }
1180 
1181         /*
1182          * If they are requesting more space, and our current estimate
1183          * is over quota, they get to try again unless the actual
1184          * on-disk is over quota and there are no pending changes (which
1185          * may free up space for us).
1186          */
1187         if (used_on_disk + est_inflight >= quota) {
1188                 if (est_inflight > 0 || used_on_disk < quota ||
1189                     (retval == ENOSPC && used_on_disk < quota + deferred))
1190                         retval = ERESTART;
1191                 dprintf_dd(dd, "failing: used=%lluK inflight = %lluK "
1192                     "quota=%lluK tr=%lluK err=%d\n",
1193                     used_on_disk>>10, est_inflight>>10,
1194                     quota>>10, asize>>10, retval);
1195                 mutex_exit(&dd->dd_lock);
1196                 return (SET_ERROR(retval));
1197         }
1198 
1199         /* We need to up our estimated delta before dropping dd_lock */
1200         dd->dd_tempreserved[txgidx] += asize;
1201 
1202         parent_rsrv = parent_delta(dd, used_on_disk + est_inflight,
1203             asize - ref_rsrv);
1204         mutex_exit(&dd->dd_lock);
1205 
1206         tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
1207         tr->tr_ds = dd;
1208         tr->tr_size = asize;
1209         list_insert_tail(tr_list, tr);
1210 
1211         /* see if it's OK with our parent */
1212         if (dd->dd_parent && parent_rsrv) {
1213                 boolean_t ismos = (dsl_dir_phys(dd)->dd_head_dataset_obj == 0);
1214 
1215                 return (dsl_dir_tempreserve_impl(dd->dd_parent,
1216                     parent_rsrv, netfree, ismos, TRUE, tr_list, tx, FALSE));
1217         } else {
1218                 return (0);
1219         }
1220 }
1221 
1222 /*
1223  * Reserve space in this dsl_dir, to be used in this tx's txg.
1224  * After the space has been dirtied (and dsl_dir_willuse_space()
1225  * has been called), the reservation should be canceled, using
1226  * dsl_dir_tempreserve_clear().
1227  */
1228 int
1229 dsl_dir_tempreserve_space(dsl_dir_t *dd, uint64_t lsize, uint64_t asize,
1230     uint64_t fsize, uint64_t usize, void **tr_cookiep, dmu_tx_t *tx)
1231 {
1232         int err;
1233         list_t *tr_list;
1234 
1235         if (asize == 0) {
1236                 *tr_cookiep = NULL;
1237                 return (0);
1238         }
1239 
1240         tr_list = kmem_alloc(sizeof (list_t), KM_SLEEP);
1241         list_create(tr_list, sizeof (struct tempreserve),
1242             offsetof(struct tempreserve, tr_node));
1243         ASSERT3S(asize, >, 0);
1244         ASSERT3S(fsize, >=, 0);
1245 
1246         err = arc_tempreserve_space(lsize, tx->tx_txg);
1247         if (err == 0) {
1248                 struct tempreserve *tr;
1249 
1250                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
1251                 tr->tr_size = lsize;
1252                 list_insert_tail(tr_list, tr);
1253         } else {
1254                 if (err == EAGAIN) {
1255                         /*
1256                          * If arc_memory_throttle() detected that pageout
1257                          * is running and we are low on memory, we delay new
1258                          * non-pageout transactions to give pageout an
1259                          * advantage.
1260                          *
1261                          * It is unfortunate to be delaying while the caller's
1262                          * locks are held.
1263                          */
1264                         txg_delay(dd->dd_pool, tx->tx_txg,
1265                             MSEC2NSEC(10), MSEC2NSEC(10));
1266                         err = SET_ERROR(ERESTART);
1267                 }
1268         }
1269 
1270         if (err == 0) {
1271                 err = dsl_dir_tempreserve_impl(dd, asize, fsize >= asize,
1272                     FALSE, asize > usize, tr_list, tx, TRUE);
1273         }
1274 
1275         if (err != 0)
1276                 dsl_dir_tempreserve_clear(tr_list, tx);
1277         else
1278                 *tr_cookiep = tr_list;
1279 
1280         return (err);
1281 }
1282 
1283 /*
1284  * Clear a temporary reservation that we previously made with
1285  * dsl_dir_tempreserve_space().
1286  */
1287 void
1288 dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
1289 {
1290         int txgidx = tx->tx_txg & TXG_MASK;
1291         list_t *tr_list = tr_cookie;
1292         struct tempreserve *tr;
1293 
1294         ASSERT3U(tx->tx_txg, !=, 0);
1295 
1296         if (tr_cookie == NULL)
1297                 return;
1298 
1299         while ((tr = list_head(tr_list)) != NULL) {
1300                 if (tr->tr_ds) {
1301                         mutex_enter(&tr->tr_ds->dd_lock);
1302                         ASSERT3U(tr->tr_ds->dd_tempreserved[txgidx], >=,
1303                             tr->tr_size);
1304                         tr->tr_ds->dd_tempreserved[txgidx] -= tr->tr_size;
1305                         mutex_exit(&tr->tr_ds->dd_lock);
1306                 } else {
1307                         arc_tempreserve_clear(tr->tr_size);
1308                 }
1309                 list_remove(tr_list, tr);
1310                 kmem_free(tr, sizeof (struct tempreserve));
1311         }
1312 
1313         kmem_free(tr_list, sizeof (list_t));
1314 }
1315 
1316 /*
1317  * This should be called from open context when we think we're going to write
1318  * or free space, for example when dirtying data. Be conservative; it's okay
1319  * to write less space or free more, but we don't want to write more or free
1320  * less than the amount specified.
1321  */
1322 void
1323 dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
1324 {
1325         int64_t parent_space;
1326         uint64_t est_used;
1327 
1328         mutex_enter(&dd->dd_lock);
1329         if (space > 0)
1330                 dd->dd_space_towrite[tx->tx_txg & TXG_MASK] += space;
1331 
1332         est_used = dsl_dir_space_towrite(dd) + dsl_dir_phys(dd)->dd_used_bytes;
1333         parent_space = parent_delta(dd, est_used, space);
1334         mutex_exit(&dd->dd_lock);
1335 
1336         /* Make sure that we clean up dd_space_to* */
1337         dsl_dir_dirty(dd, tx);
1338 
1339         /* XXX this is potentially expensive and unnecessary... */
1340         if (parent_space && dd->dd_parent)
1341                 dsl_dir_willuse_space(dd->dd_parent, parent_space, tx);
1342 }
1343 
1344 /* call from syncing context when we actually write/free space for this dd */
1345 void
1346 dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
1347     int64_t used, int64_t compressed, int64_t uncompressed, dmu_tx_t *tx)
1348 {
1349         int64_t accounted_delta;
1350 
1351         /*
1352          * dsl_dataset_set_refreservation_sync_impl() calls this with
1353          * dd_lock held, so that it can atomically update
1354          * ds->ds_reserved and the dsl_dir accounting, so that
1355          * dsl_dataset_check_quota() can see dataset and dir accounting
1356          * consistently.
1357          */
1358         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
1359 
1360         ASSERT(dmu_tx_is_syncing(tx));
1361         ASSERT(type < DD_USED_NUM);
1362 
1363         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1364 
1365         if (needlock)
1366                 mutex_enter(&dd->dd_lock);
1367         accounted_delta =
1368             parent_delta(dd, dsl_dir_phys(dd)->dd_used_bytes, used);
1369         ASSERT(used >= 0 || dsl_dir_phys(dd)->dd_used_bytes >= -used);
1370         ASSERT(compressed >= 0 ||
1371             dsl_dir_phys(dd)->dd_compressed_bytes >= -compressed);
1372         ASSERT(uncompressed >= 0 ||
1373             dsl_dir_phys(dd)->dd_uncompressed_bytes >= -uncompressed);
1374         dsl_dir_phys(dd)->dd_used_bytes += used;
1375         dsl_dir_phys(dd)->dd_uncompressed_bytes += uncompressed;
1376         dsl_dir_phys(dd)->dd_compressed_bytes += compressed;
1377 
1378         if (dsl_dir_phys(dd)->dd_flags & DD_FLAG_USED_BREAKDOWN) {
1379                 ASSERT(used > 0 ||
1380                     dsl_dir_phys(dd)->dd_used_breakdown[type] >= -used);
1381                 dsl_dir_phys(dd)->dd_used_breakdown[type] += used;
1382 #ifdef DEBUG
1383                 dd_used_t t;
1384                 uint64_t u = 0;
1385                 for (t = 0; t < DD_USED_NUM; t++)
1386                         u += dsl_dir_phys(dd)->dd_used_breakdown[t];
1387                 ASSERT3U(u, ==, dsl_dir_phys(dd)->dd_used_bytes);
1388 #endif
1389         }
1390         if (needlock)
1391                 mutex_exit(&dd->dd_lock);
1392 
1393         if (dd->dd_parent != NULL) {
1394                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
1395                     accounted_delta, compressed, uncompressed, tx);
1396                 dsl_dir_transfer_space(dd->dd_parent,
1397                     used - accounted_delta,
1398                     DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
1399         }
1400 }
1401 
1402 void
1403 dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
1404     dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
1405 {
1406         ASSERT(dmu_tx_is_syncing(tx));
1407         ASSERT(oldtype < DD_USED_NUM);
1408         ASSERT(newtype < DD_USED_NUM);
1409 
1410         if (delta == 0 ||
1411             !(dsl_dir_phys(dd)->dd_flags & DD_FLAG_USED_BREAKDOWN))
1412                 return;
1413 
1414         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1415         mutex_enter(&dd->dd_lock);
1416         ASSERT(delta > 0 ?
1417             dsl_dir_phys(dd)->dd_used_breakdown[oldtype] >= delta :
1418             dsl_dir_phys(dd)->dd_used_breakdown[newtype] >= -delta);
1419         ASSERT(dsl_dir_phys(dd)->dd_used_bytes >= ABS(delta));
1420         dsl_dir_phys(dd)->dd_used_breakdown[oldtype] -= delta;
1421         dsl_dir_phys(dd)->dd_used_breakdown[newtype] += delta;
1422         mutex_exit(&dd->dd_lock);
1423 }
1424 
1425 typedef struct dsl_dir_set_qr_arg {
1426         const char *ddsqra_name;
1427         zprop_source_t ddsqra_source;
1428         uint64_t ddsqra_value;
1429 } dsl_dir_set_qr_arg_t;
1430 
1431 static int
1432 dsl_dir_set_quota_check(void *arg, dmu_tx_t *tx)
1433 {
1434         dsl_dir_set_qr_arg_t *ddsqra = arg;
1435         dsl_pool_t *dp = dmu_tx_pool(tx);
1436         dsl_dataset_t *ds;
1437         int error;
1438         uint64_t towrite, newval;
1439 
1440         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
1441         if (error != 0)
1442                 return (error);
1443 
1444         error = dsl_prop_predict(ds->ds_dir, "quota",
1445             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
1446         if (error != 0) {
1447                 dsl_dataset_rele(ds, FTAG);
1448                 return (error);
1449         }
1450 
1451         if (newval == 0) {
1452                 dsl_dataset_rele(ds, FTAG);
1453                 return (0);
1454         }
1455 
1456         mutex_enter(&ds->ds_dir->dd_lock);
1457         /*
1458          * If we are doing the preliminary check in open context, and
1459          * there are pending changes, then don't fail it, since the
1460          * pending changes could under-estimate the amount of space to be
1461          * freed up.
1462          */
1463         towrite = dsl_dir_space_towrite(ds->ds_dir);
1464         if ((dmu_tx_is_syncing(tx) || towrite == 0) &&
1465             (newval < dsl_dir_phys(ds->ds_dir)->dd_reserved ||
1466             newval < dsl_dir_phys(ds->ds_dir)->dd_used_bytes + towrite)) {
1467                 error = SET_ERROR(ENOSPC);
1468         }
1469         mutex_exit(&ds->ds_dir->dd_lock);
1470         dsl_dataset_rele(ds, FTAG);
1471         return (error);
1472 }
1473 
1474 static void
1475 dsl_dir_set_quota_sync(void *arg, dmu_tx_t *tx)
1476 {
1477         dsl_dir_set_qr_arg_t *ddsqra = arg;
1478         dsl_pool_t *dp = dmu_tx_pool(tx);
1479         dsl_dataset_t *ds;
1480         uint64_t newval;
1481 
1482         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
1483 
1484         if (spa_version(dp->dp_spa) >= SPA_VERSION_RECVD_PROPS) {
1485                 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_QUOTA),
1486                     ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
1487                     &ddsqra->ddsqra_value, tx);
1488 
1489                 VERIFY0(dsl_prop_get_int_ds(ds,
1490                     zfs_prop_to_name(ZFS_PROP_QUOTA), &newval));
1491         } else {
1492                 newval = ddsqra->ddsqra_value;
1493                 spa_history_log_internal_ds(ds, "set", tx, "%s=%lld",
1494                     zfs_prop_to_name(ZFS_PROP_QUOTA), (longlong_t)newval);
1495         }
1496 
1497         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
1498         mutex_enter(&ds->ds_dir->dd_lock);
1499         dsl_dir_phys(ds->ds_dir)->dd_quota = newval;
1500         mutex_exit(&ds->ds_dir->dd_lock);
1501         dsl_dataset_rele(ds, FTAG);
1502 }
1503 
1504 int
1505 dsl_dir_set_quota(const char *ddname, zprop_source_t source, uint64_t quota)
1506 {
1507         dsl_dir_set_qr_arg_t ddsqra;
1508 
1509         ddsqra.ddsqra_name = ddname;
1510         ddsqra.ddsqra_source = source;
1511         ddsqra.ddsqra_value = quota;
1512 
1513         return (dsl_sync_task(ddname, dsl_dir_set_quota_check,
1514             dsl_dir_set_quota_sync, &ddsqra, 0, ZFS_SPACE_CHECK_NONE));
1515 }
1516 
1517 int
1518 dsl_dir_set_reservation_check(void *arg, dmu_tx_t *tx)
1519 {
1520         dsl_dir_set_qr_arg_t *ddsqra = arg;
1521         dsl_pool_t *dp = dmu_tx_pool(tx);
1522         dsl_dataset_t *ds;
1523         dsl_dir_t *dd;
1524         uint64_t newval, used, avail;
1525         int error;
1526 
1527         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
1528         if (error != 0)
1529                 return (error);
1530         dd = ds->ds_dir;
1531 
1532         /*
1533          * If we are doing the preliminary check in open context, the
1534          * space estimates may be inaccurate.
1535          */
1536         if (!dmu_tx_is_syncing(tx)) {
1537                 dsl_dataset_rele(ds, FTAG);
1538                 return (0);
1539         }
1540 
1541         error = dsl_prop_predict(ds->ds_dir,
1542             zfs_prop_to_name(ZFS_PROP_RESERVATION),
1543             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
1544         if (error != 0) {
1545                 dsl_dataset_rele(ds, FTAG);
1546                 return (error);
1547         }
1548 
1549         mutex_enter(&dd->dd_lock);
1550         used = dsl_dir_phys(dd)->dd_used_bytes;
1551         mutex_exit(&dd->dd_lock);
1552 
1553         if (dd->dd_parent) {
1554                 avail = dsl_dir_space_available(dd->dd_parent,
1555                     NULL, 0, FALSE);
1556         } else {
1557                 avail = dsl_pool_adjustedsize(dd->dd_pool, B_FALSE) - used;
1558         }
1559 
1560         if (MAX(used, newval) > MAX(used, dsl_dir_phys(dd)->dd_reserved)) {
1561                 uint64_t delta = MAX(used, newval) -
1562                     MAX(used, dsl_dir_phys(dd)->dd_reserved);
1563 
1564                 if (delta > avail ||
1565                     (dsl_dir_phys(dd)->dd_quota > 0 &&
1566                     newval > dsl_dir_phys(dd)->dd_quota))
1567                         error = SET_ERROR(ENOSPC);
1568         }
1569 
1570         dsl_dataset_rele(ds, FTAG);
1571         return (error);
1572 }
1573 
1574 void
1575 dsl_dir_set_reservation_sync_impl(dsl_dir_t *dd, uint64_t value, dmu_tx_t *tx)
1576 {
1577         uint64_t used;
1578         int64_t delta;
1579 
1580         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1581 
1582         mutex_enter(&dd->dd_lock);
1583         used = dsl_dir_phys(dd)->dd_used_bytes;
1584         delta = MAX(used, value) - MAX(used, dsl_dir_phys(dd)->dd_reserved);
1585         dsl_dir_phys(dd)->dd_reserved = value;
1586 
1587         if (dd->dd_parent != NULL) {
1588                 /* Roll up this additional usage into our ancestors */
1589                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1590                     delta, 0, 0, tx);
1591         }
1592         mutex_exit(&dd->dd_lock);
1593 }
1594 
1595 
1596 static void
1597 dsl_dir_set_reservation_sync(void *arg, dmu_tx_t *tx)
1598 {
1599         dsl_dir_set_qr_arg_t *ddsqra = arg;
1600         dsl_pool_t *dp = dmu_tx_pool(tx);
1601         dsl_dataset_t *ds;
1602         uint64_t newval;
1603 
1604         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
1605 
1606         if (spa_version(dp->dp_spa) >= SPA_VERSION_RECVD_PROPS) {
1607                 dsl_prop_set_sync_impl(ds,
1608                     zfs_prop_to_name(ZFS_PROP_RESERVATION),
1609                     ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
1610                     &ddsqra->ddsqra_value, tx);
1611 
1612                 VERIFY0(dsl_prop_get_int_ds(ds,
1613                     zfs_prop_to_name(ZFS_PROP_RESERVATION), &newval));
1614         } else {
1615                 newval = ddsqra->ddsqra_value;
1616                 spa_history_log_internal_ds(ds, "set", tx, "%s=%lld",
1617                     zfs_prop_to_name(ZFS_PROP_RESERVATION),
1618                     (longlong_t)newval);
1619         }
1620 
1621         dsl_dir_set_reservation_sync_impl(ds->ds_dir, newval, tx);
1622         dsl_dataset_rele(ds, FTAG);
1623 }
1624 
1625 int
1626 dsl_dir_set_reservation(const char *ddname, zprop_source_t source,
1627     uint64_t reservation)
1628 {
1629         dsl_dir_set_qr_arg_t ddsqra;
1630 
1631         ddsqra.ddsqra_name = ddname;
1632         ddsqra.ddsqra_source = source;
1633         ddsqra.ddsqra_value = reservation;
1634 
1635         return (dsl_sync_task(ddname, dsl_dir_set_reservation_check,
1636             dsl_dir_set_reservation_sync, &ddsqra, 0, ZFS_SPACE_CHECK_NONE));
1637 }
1638 
1639 static dsl_dir_t *
1640 closest_common_ancestor(dsl_dir_t *ds1, dsl_dir_t *ds2)
1641 {
1642         for (; ds1; ds1 = ds1->dd_parent) {
1643                 dsl_dir_t *dd;
1644                 for (dd = ds2; dd; dd = dd->dd_parent) {
1645                         if (ds1 == dd)
1646                                 return (dd);
1647                 }
1648         }
1649         return (NULL);
1650 }
1651 
1652 /*
1653  * If delta is applied to dd, how much of that delta would be applied to
1654  * ancestor?  Syncing context only.
1655  */
1656 static int64_t
1657 would_change(dsl_dir_t *dd, int64_t delta, dsl_dir_t *ancestor)
1658 {
1659         if (dd == ancestor)
1660                 return (delta);
1661 
1662         mutex_enter(&dd->dd_lock);
1663         delta = parent_delta(dd, dsl_dir_phys(dd)->dd_used_bytes, delta);
1664         mutex_exit(&dd->dd_lock);
1665         return (would_change(dd->dd_parent, delta, ancestor));
1666 }
1667 
1668 typedef struct dsl_dir_rename_arg {
1669         const char *ddra_oldname;
1670         const char *ddra_newname;
1671         cred_t *ddra_cred;
1672 } dsl_dir_rename_arg_t;
1673 
1674 /* ARGSUSED */
1675 static int
1676 dsl_valid_rename(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
1677 {
1678         int *deltap = arg;
1679         char namebuf[MAXNAMELEN];
1680 
1681         dsl_dataset_name(ds, namebuf);
1682 
1683         if (strlen(namebuf) + *deltap >= MAXNAMELEN)
1684                 return (SET_ERROR(ENAMETOOLONG));
1685         return (0);
1686 }
1687 
1688 static int
1689 dsl_dir_rename_check(void *arg, dmu_tx_t *tx)
1690 {
1691         dsl_dir_rename_arg_t *ddra = arg;
1692         dsl_pool_t *dp = dmu_tx_pool(tx);
1693         dsl_dir_t *dd, *newparent;
1694         const char *mynewname;
1695         int error;
1696         int delta = strlen(ddra->ddra_newname) - strlen(ddra->ddra_oldname);
1697 
1698         /* target dir should exist */
1699         error = dsl_dir_hold(dp, ddra->ddra_oldname, FTAG, &dd, NULL);
1700         if (error != 0)
1701                 return (error);
1702 
1703         /* new parent should exist */
1704         error = dsl_dir_hold(dp, ddra->ddra_newname, FTAG,
1705             &newparent, &mynewname);
1706         if (error != 0) {
1707                 dsl_dir_rele(dd, FTAG);
1708                 return (error);
1709         }
1710 
1711         /* can't rename to different pool */
1712         if (dd->dd_pool != newparent->dd_pool) {
1713                 dsl_dir_rele(newparent, FTAG);
1714                 dsl_dir_rele(dd, FTAG);
1715                 return (SET_ERROR(ENXIO));
1716         }
1717 
1718         /* new name should not already exist */
1719         if (mynewname == NULL) {
1720                 dsl_dir_rele(newparent, FTAG);
1721                 dsl_dir_rele(dd, FTAG);
1722                 return (SET_ERROR(EEXIST));
1723         }
1724 
1725         /* if the name length is growing, validate child name lengths */
1726         if (delta > 0) {
1727                 error = dmu_objset_find_dp(dp, dd->dd_object, dsl_valid_rename,
1728                     &delta, DS_FIND_CHILDREN | DS_FIND_SNAPSHOTS);
1729                 if (error != 0) {
1730                         dsl_dir_rele(newparent, FTAG);
1731                         dsl_dir_rele(dd, FTAG);
1732                         return (error);
1733                 }
1734         }
1735 
1736         if (dmu_tx_is_syncing(tx)) {
1737                 if (spa_feature_is_active(dp->dp_spa,
1738                     SPA_FEATURE_FS_SS_LIMIT)) {
1739                         /*
1740                          * Although this is the check function and we don't
1741                          * normally make on-disk changes in check functions,
1742                          * we need to do that here.
1743                          *
1744                          * Ensure this portion of the tree's counts have been
1745                          * initialized in case the new parent has limits set.
1746                          */
1747                         dsl_dir_init_fs_ss_count(dd, tx);
1748                 }
1749         }
1750 
1751         if (newparent != dd->dd_parent) {
1752                 /* is there enough space? */
1753                 uint64_t myspace =
1754                     MAX(dsl_dir_phys(dd)->dd_used_bytes,
1755                     dsl_dir_phys(dd)->dd_reserved);
1756                 objset_t *os = dd->dd_pool->dp_meta_objset;
1757                 uint64_t fs_cnt = 0;
1758                 uint64_t ss_cnt = 0;
1759 
1760                 if (dsl_dir_is_zapified(dd)) {
1761                         int err;
1762 
1763                         err = zap_lookup(os, dd->dd_object,
1764                             DD_FIELD_FILESYSTEM_COUNT, sizeof (fs_cnt), 1,
1765                             &fs_cnt);
1766                         if (err != ENOENT && err != 0) {
1767                                 dsl_dir_rele(newparent, FTAG);
1768                                 dsl_dir_rele(dd, FTAG);
1769                                 return (err);
1770                         }
1771 
1772                         /*
1773                          * have to add 1 for the filesystem itself that we're
1774                          * moving
1775                          */
1776                         fs_cnt++;
1777 
1778                         err = zap_lookup(os, dd->dd_object,
1779                             DD_FIELD_SNAPSHOT_COUNT, sizeof (ss_cnt), 1,
1780                             &ss_cnt);
1781                         if (err != ENOENT && err != 0) {
1782                                 dsl_dir_rele(newparent, FTAG);
1783                                 dsl_dir_rele(dd, FTAG);
1784                                 return (err);
1785                         }
1786                 }
1787 
1788                 /* no rename into our descendant */
1789                 if (closest_common_ancestor(dd, newparent) == dd) {
1790                         dsl_dir_rele(newparent, FTAG);
1791                         dsl_dir_rele(dd, FTAG);
1792                         return (SET_ERROR(EINVAL));
1793                 }
1794 
1795                 error = dsl_dir_transfer_possible(dd->dd_parent,
1796                     newparent, fs_cnt, ss_cnt, myspace, ddra->ddra_cred);
1797                 if (error != 0) {
1798                         dsl_dir_rele(newparent, FTAG);
1799                         dsl_dir_rele(dd, FTAG);
1800                         return (error);
1801                 }
1802         }
1803 
1804         dsl_dir_rele(newparent, FTAG);
1805         dsl_dir_rele(dd, FTAG);
1806         return (0);
1807 }
1808 
1809 static void
1810 dsl_dir_rename_sync(void *arg, dmu_tx_t *tx)
1811 {
1812         dsl_dir_rename_arg_t *ddra = arg;
1813         dsl_pool_t *dp = dmu_tx_pool(tx);
1814         dsl_dir_t *dd, *newparent;
1815         const char *mynewname;
1816         int error;
1817         objset_t *mos = dp->dp_meta_objset;
1818 
1819         VERIFY0(dsl_dir_hold(dp, ddra->ddra_oldname, FTAG, &dd, NULL));
1820         VERIFY0(dsl_dir_hold(dp, ddra->ddra_newname, FTAG, &newparent,
1821             &mynewname));
1822 
1823         /* Log this before we change the name. */
1824         spa_history_log_internal_dd(dd, "rename", tx,
1825             "-> %s", ddra->ddra_newname);
1826 
1827         if (newparent != dd->dd_parent) {
1828                 objset_t *os = dd->dd_pool->dp_meta_objset;
1829                 uint64_t fs_cnt = 0;
1830                 uint64_t ss_cnt = 0;
1831 
1832                 /*
1833                  * We already made sure the dd counts were initialized in the
1834                  * check function.
1835                  */
1836                 if (spa_feature_is_active(dp->dp_spa,
1837                     SPA_FEATURE_FS_SS_LIMIT)) {
1838                         VERIFY0(zap_lookup(os, dd->dd_object,
1839                             DD_FIELD_FILESYSTEM_COUNT, sizeof (fs_cnt), 1,
1840                             &fs_cnt));
1841                         /* add 1 for the filesystem itself that we're moving */
1842                         fs_cnt++;
1843 
1844                         VERIFY0(zap_lookup(os, dd->dd_object,
1845                             DD_FIELD_SNAPSHOT_COUNT, sizeof (ss_cnt), 1,
1846                             &ss_cnt));
1847                 }
1848 
1849                 dsl_fs_ss_count_adjust(dd->dd_parent, -fs_cnt,
1850                     DD_FIELD_FILESYSTEM_COUNT, tx);
1851                 dsl_fs_ss_count_adjust(newparent, fs_cnt,
1852                     DD_FIELD_FILESYSTEM_COUNT, tx);
1853 
1854                 dsl_fs_ss_count_adjust(dd->dd_parent, -ss_cnt,
1855                     DD_FIELD_SNAPSHOT_COUNT, tx);
1856                 dsl_fs_ss_count_adjust(newparent, ss_cnt,
1857                     DD_FIELD_SNAPSHOT_COUNT, tx);
1858 
1859                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
1860                     -dsl_dir_phys(dd)->dd_used_bytes,
1861                     -dsl_dir_phys(dd)->dd_compressed_bytes,
1862                     -dsl_dir_phys(dd)->dd_uncompressed_bytes, tx);
1863                 dsl_dir_diduse_space(newparent, DD_USED_CHILD,
1864                     dsl_dir_phys(dd)->dd_used_bytes,
1865                     dsl_dir_phys(dd)->dd_compressed_bytes,
1866                     dsl_dir_phys(dd)->dd_uncompressed_bytes, tx);
1867 
1868                 if (dsl_dir_phys(dd)->dd_reserved >
1869                     dsl_dir_phys(dd)->dd_used_bytes) {
1870                         uint64_t unused_rsrv = dsl_dir_phys(dd)->dd_reserved -
1871                             dsl_dir_phys(dd)->dd_used_bytes;
1872 
1873                         dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1874                             -unused_rsrv, 0, 0, tx);
1875                         dsl_dir_diduse_space(newparent, DD_USED_CHILD_RSRV,
1876                             unused_rsrv, 0, 0, tx);
1877                 }
1878         }
1879 
1880         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1881 
1882         /* remove from old parent zapobj */
1883         error = zap_remove(mos,
1884             dsl_dir_phys(dd->dd_parent)->dd_child_dir_zapobj,
1885             dd->dd_myname, tx);
1886         ASSERT0(error);
1887 
1888         (void) strcpy(dd->dd_myname, mynewname);
1889         dsl_dir_rele(dd->dd_parent, dd);
1890         dsl_dir_phys(dd)->dd_parent_obj = newparent->dd_object;
1891         VERIFY0(dsl_dir_hold_obj(dp,
1892             newparent->dd_object, NULL, dd, &dd->dd_parent));
1893 
1894         /* add to new parent zapobj */
1895         VERIFY0(zap_add(mos, dsl_dir_phys(newparent)->dd_child_dir_zapobj,
1896             dd->dd_myname, 8, 1, &dd->dd_object, tx));
1897 
1898         dsl_prop_notify_all(dd);
1899 
1900         dsl_dir_rele(newparent, FTAG);
1901         dsl_dir_rele(dd, FTAG);
1902 }
1903 
1904 int
1905 dsl_dir_rename(const char *oldname, const char *newname)
1906 {
1907         dsl_dir_rename_arg_t ddra;
1908 
1909         ddra.ddra_oldname = oldname;
1910         ddra.ddra_newname = newname;
1911         ddra.ddra_cred = CRED();
1912 
1913         return (dsl_sync_task(oldname,
1914             dsl_dir_rename_check, dsl_dir_rename_sync, &ddra,
1915             3, ZFS_SPACE_CHECK_RESERVED));
1916 }
1917 
1918 int
1919 dsl_dir_transfer_possible(dsl_dir_t *sdd, dsl_dir_t *tdd,
1920     uint64_t fs_cnt, uint64_t ss_cnt, uint64_t space, cred_t *cr)
1921 {
1922         dsl_dir_t *ancestor;
1923         int64_t adelta;
1924         uint64_t avail;
1925         int err;
1926 
1927         ancestor = closest_common_ancestor(sdd, tdd);
1928         adelta = would_change(sdd, -space, ancestor);
1929         avail = dsl_dir_space_available(tdd, ancestor, adelta, FALSE);
1930         if (avail < space)
1931                 return (SET_ERROR(ENOSPC));
1932 
1933         err = dsl_fs_ss_limit_check(tdd, fs_cnt, ZFS_PROP_FILESYSTEM_LIMIT,
1934             ancestor, cr);
1935         if (err != 0)
1936                 return (err);
1937         err = dsl_fs_ss_limit_check(tdd, ss_cnt, ZFS_PROP_SNAPSHOT_LIMIT,
1938             ancestor, cr);
1939         if (err != 0)
1940                 return (err);
1941 
1942         return (0);
1943 }
1944 
1945 timestruc_t
1946 dsl_dir_snap_cmtime(dsl_dir_t *dd)
1947 {
1948         timestruc_t t;
1949 
1950         mutex_enter(&dd->dd_lock);
1951         t = dd->dd_snap_cmtime;
1952         mutex_exit(&dd->dd_lock);
1953 
1954         return (t);
1955 }
1956 
1957 void
1958 dsl_dir_snap_cmtime_update(dsl_dir_t *dd)
1959 {
1960         timestruc_t t;
1961 
1962         gethrestime(&t);
1963         mutex_enter(&dd->dd_lock);
1964         dd->dd_snap_cmtime = t;
1965         mutex_exit(&dd->dd_lock);
1966 }
1967 
1968 void
1969 dsl_dir_zapify(dsl_dir_t *dd, dmu_tx_t *tx)
1970 {
1971         objset_t *mos = dd->dd_pool->dp_meta_objset;
1972         dmu_object_zapify(mos, dd->dd_object, DMU_OT_DSL_DIR, tx);
1973 }
1974 
1975 boolean_t
1976 dsl_dir_is_zapified(dsl_dir_t *dd)
1977 {
1978         dmu_object_info_t doi;
1979 
1980         dmu_object_info_from_db(dd->dd_dbuf, &doi);
1981         return (doi.doi_type == DMU_OTN_ZAP_METADATA);
1982 }