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) 2013 by Delphix. All rights reserved.
  24  * Copyright (c) 2013 Martin Matuska. All rights reserved.
  25  */
  26 
  27 #include <sys/dmu.h>
  28 #include <sys/dmu_objset.h>
  29 #include <sys/dmu_tx.h>
  30 #include <sys/dsl_dataset.h>
  31 #include <sys/dsl_dir.h>
  32 #include <sys/dsl_prop.h>
  33 #include <sys/dsl_synctask.h>
  34 #include <sys/dsl_deleg.h>
  35 #include <sys/spa.h>
  36 #include <sys/metaslab.h>
  37 #include <sys/zap.h>
  38 #include <sys/zio.h>
  39 #include <sys/arc.h>
  40 #include <sys/sunddi.h>
  41 #include "zfs_namecheck.h"
  42 
  43 static uint64_t dsl_dir_space_towrite(dsl_dir_t *dd);
  44 
  45 /* ARGSUSED */
  46 static void
  47 dsl_dir_evict(dmu_buf_t *db, void *arg)
  48 {
  49         dsl_dir_t *dd = arg;
  50         dsl_pool_t *dp = dd->dd_pool;
  51         int t;
  52 
  53         for (t = 0; t < TXG_SIZE; t++) {
  54                 ASSERT(!txg_list_member(&dp->dp_dirty_dirs, dd, t));
  55                 ASSERT(dd->dd_tempreserved[t] == 0);
  56                 ASSERT(dd->dd_space_towrite[t] == 0);
  57         }
  58 
  59         if (dd->dd_parent)
  60                 dsl_dir_rele(dd->dd_parent, dd);
  61 
  62         spa_close(dd->dd_pool->dp_spa, dd);
  63 
  64         /*
  65          * The props callback list should have been cleaned up by
  66          * objset_evict().
  67          */
  68         list_destroy(&dd->dd_prop_cbs);
  69         mutex_destroy(&dd->dd_lock);
  70         kmem_free(dd, sizeof (dsl_dir_t));
  71 }
  72 
  73 int
  74 dsl_dir_hold_obj(dsl_pool_t *dp, uint64_t ddobj,
  75     const char *tail, void *tag, dsl_dir_t **ddp)
  76 {
  77         dmu_buf_t *dbuf;
  78         dsl_dir_t *dd;
  79         int err;
  80 
  81         ASSERT(dsl_pool_config_held(dp));
  82 
  83         err = dmu_bonus_hold(dp->dp_meta_objset, ddobj, tag, &dbuf);
  84         if (err != 0)
  85                 return (err);
  86         dd = dmu_buf_get_user(dbuf);
  87 #ifdef ZFS_DEBUG
  88         {
  89                 dmu_object_info_t doi;
  90                 dmu_object_info_from_db(dbuf, &doi);
  91                 ASSERT3U(doi.doi_type, ==, DMU_OT_DSL_DIR);
  92                 ASSERT3U(doi.doi_bonus_size, >=, sizeof (dsl_dir_phys_t));
  93         }
  94 #endif
  95         if (dd == NULL) {
  96                 dsl_dir_t *winner;
  97 
  98                 dd = kmem_zalloc(sizeof (dsl_dir_t), KM_SLEEP);
  99                 dd->dd_object = ddobj;
 100                 dd->dd_dbuf = dbuf;
 101                 dd->dd_pool = dp;
 102                 dd->dd_phys = dbuf->db_data;
 103                 mutex_init(&dd->dd_lock, NULL, MUTEX_DEFAULT, NULL);
 104 
 105                 list_create(&dd->dd_prop_cbs, sizeof (dsl_prop_cb_record_t),
 106                     offsetof(dsl_prop_cb_record_t, cbr_node));
 107 
 108                 dsl_dir_snap_cmtime_update(dd);
 109 
 110                 if (dd->dd_phys->dd_parent_obj) {
 111                         err = dsl_dir_hold_obj(dp, dd->dd_phys->dd_parent_obj,
 112                             NULL, dd, &dd->dd_parent);
 113                         if (err != 0)
 114                                 goto errout;
 115                         if (tail) {
 116 #ifdef ZFS_DEBUG
 117                                 uint64_t foundobj;
 118 
 119                                 err = zap_lookup(dp->dp_meta_objset,
 120                                     dd->dd_parent->dd_phys->dd_child_dir_zapobj,
 121                                     tail, sizeof (foundobj), 1, &foundobj);
 122                                 ASSERT(err || foundobj == ddobj);
 123 #endif
 124                                 (void) strcpy(dd->dd_myname, tail);
 125                         } else {
 126                                 err = zap_value_search(dp->dp_meta_objset,
 127                                     dd->dd_parent->dd_phys->dd_child_dir_zapobj,
 128                                     ddobj, 0, dd->dd_myname);
 129                         }
 130                         if (err != 0)
 131                                 goto errout;
 132                 } else {
 133                         (void) strcpy(dd->dd_myname, spa_name(dp->dp_spa));
 134                 }
 135 
 136                 if (dsl_dir_is_clone(dd)) {
 137                         dmu_buf_t *origin_bonus;
 138                         dsl_dataset_phys_t *origin_phys;
 139 
 140                         /*
 141                          * We can't open the origin dataset, because
 142                          * that would require opening this dsl_dir.
 143                          * Just look at its phys directly instead.
 144                          */
 145                         err = dmu_bonus_hold(dp->dp_meta_objset,
 146                             dd->dd_phys->dd_origin_obj, FTAG, &origin_bonus);
 147                         if (err != 0)
 148                                 goto errout;
 149                         origin_phys = origin_bonus->db_data;
 150                         dd->dd_origin_txg =
 151                             origin_phys->ds_creation_txg;
 152                         dmu_buf_rele(origin_bonus, FTAG);
 153                 }
 154 
 155                 winner = dmu_buf_set_user_ie(dbuf, dd, &dd->dd_phys,
 156                     dsl_dir_evict);
 157                 if (winner) {
 158                         if (dd->dd_parent)
 159                                 dsl_dir_rele(dd->dd_parent, dd);
 160                         mutex_destroy(&dd->dd_lock);
 161                         kmem_free(dd, sizeof (dsl_dir_t));
 162                         dd = winner;
 163                 } else {
 164                         spa_open_ref(dp->dp_spa, dd);
 165                 }
 166         }
 167 
 168         /*
 169          * The dsl_dir_t has both open-to-close and instantiate-to-evict
 170          * holds on the spa.  We need the open-to-close holds because
 171          * otherwise the spa_refcnt wouldn't change when we open a
 172          * dir which the spa also has open, so we could incorrectly
 173          * think it was OK to unload/export/destroy the pool.  We need
 174          * the instantiate-to-evict hold because the dsl_dir_t has a
 175          * pointer to the dd_pool, which has a pointer to the spa_t.
 176          */
 177         spa_open_ref(dp->dp_spa, tag);
 178         ASSERT3P(dd->dd_pool, ==, dp);
 179         ASSERT3U(dd->dd_object, ==, ddobj);
 180         ASSERT3P(dd->dd_dbuf, ==, dbuf);
 181         *ddp = dd;
 182         return (0);
 183 
 184 errout:
 185         if (dd->dd_parent)
 186                 dsl_dir_rele(dd->dd_parent, dd);
 187         mutex_destroy(&dd->dd_lock);
 188         kmem_free(dd, sizeof (dsl_dir_t));
 189         dmu_buf_rele(dbuf, tag);
 190         return (err);
 191 }
 192 
 193 void
 194 dsl_dir_rele(dsl_dir_t *dd, void *tag)
 195 {
 196         dprintf_dd(dd, "%s\n", "");
 197         spa_close(dd->dd_pool->dp_spa, tag);
 198         dmu_buf_rele(dd->dd_dbuf, tag);
 199 }
 200 
 201 /* buf must be long enough (MAXNAMELEN + strlen(MOS_DIR_NAME) + 1 should do) */
 202 void
 203 dsl_dir_name(dsl_dir_t *dd, char *buf)
 204 {
 205         if (dd->dd_parent) {
 206                 dsl_dir_name(dd->dd_parent, buf);
 207                 (void) strcat(buf, "/");
 208         } else {
 209                 buf[0] = '\0';
 210         }
 211         if (!MUTEX_HELD(&dd->dd_lock)) {
 212                 /*
 213                  * recursive mutex so that we can use
 214                  * dprintf_dd() with dd_lock held
 215                  */
 216                 mutex_enter(&dd->dd_lock);
 217                 (void) strcat(buf, dd->dd_myname);
 218                 mutex_exit(&dd->dd_lock);
 219         } else {
 220                 (void) strcat(buf, dd->dd_myname);
 221         }
 222 }
 223 
 224 /* Calculate name length, avoiding all the strcat calls of dsl_dir_name */
 225 int
 226 dsl_dir_namelen(dsl_dir_t *dd)
 227 {
 228         int result = 0;
 229 
 230         if (dd->dd_parent) {
 231                 /* parent's name + 1 for the "/" */
 232                 result = dsl_dir_namelen(dd->dd_parent) + 1;
 233         }
 234 
 235         if (!MUTEX_HELD(&dd->dd_lock)) {
 236                 /* see dsl_dir_name */
 237                 mutex_enter(&dd->dd_lock);
 238                 result += strlen(dd->dd_myname);
 239                 mutex_exit(&dd->dd_lock);
 240         } else {
 241                 result += strlen(dd->dd_myname);
 242         }
 243 
 244         return (result);
 245 }
 246 
 247 static int
 248 getcomponent(const char *path, char *component, const char **nextp)
 249 {
 250         char *p;
 251 
 252         if ((path == NULL) || (path[0] == '\0'))
 253                 return (SET_ERROR(ENOENT));
 254         /* This would be a good place to reserve some namespace... */
 255         p = strpbrk(path, "/@");
 256         if (p && (p[1] == '/' || p[1] == '@')) {
 257                 /* two separators in a row */
 258                 return (SET_ERROR(EINVAL));
 259         }
 260         if (p == NULL || p == path) {
 261                 /*
 262                  * if the first thing is an @ or /, it had better be an
 263                  * @ and it had better not have any more ats or slashes,
 264                  * and it had better have something after the @.
 265                  */
 266                 if (p != NULL &&
 267                     (p[0] != '@' || strpbrk(path+1, "/@") || p[1] == '\0'))
 268                         return (SET_ERROR(EINVAL));
 269                 if (strlen(path) >= MAXNAMELEN)
 270                         return (SET_ERROR(ENAMETOOLONG));
 271                 (void) strcpy(component, path);
 272                 p = NULL;
 273         } else if (p[0] == '/') {
 274                 if (p - path >= MAXNAMELEN)
 275                         return (SET_ERROR(ENAMETOOLONG));
 276                 (void) strncpy(component, path, p - path);
 277                 component[p - path] = '\0';
 278                 p++;
 279         } else if (p[0] == '@') {
 280                 /*
 281                  * if the next separator is an @, there better not be
 282                  * any more slashes.
 283                  */
 284                 if (strchr(path, '/'))
 285                         return (SET_ERROR(EINVAL));
 286                 if (p - path >= MAXNAMELEN)
 287                         return (SET_ERROR(ENAMETOOLONG));
 288                 (void) strncpy(component, path, p - path);
 289                 component[p - path] = '\0';
 290         } else {
 291                 panic("invalid p=%p", (void *)p);
 292         }
 293         *nextp = p;
 294         return (0);
 295 }
 296 
 297 /*
 298  * Return the dsl_dir_t, and possibly the last component which couldn't
 299  * be found in *tail.  The name must be in the specified dsl_pool_t.  This
 300  * thread must hold the dp_config_rwlock for the pool.  Returns NULL if the
 301  * path is bogus, or if tail==NULL and we couldn't parse the whole name.
 302  * (*tail)[0] == '@' means that the last component is a snapshot.
 303  */
 304 int
 305 dsl_dir_hold(dsl_pool_t *dp, const char *name, void *tag,
 306     dsl_dir_t **ddp, const char **tailp)
 307 {
 308         char buf[MAXNAMELEN];
 309         const char *spaname, *next, *nextnext = NULL;
 310         int err;
 311         dsl_dir_t *dd;
 312         uint64_t ddobj;
 313 
 314         err = getcomponent(name, buf, &next);
 315         if (err != 0)
 316                 return (err);
 317 
 318         /* Make sure the name is in the specified pool. */
 319         spaname = spa_name(dp->dp_spa);
 320         if (strcmp(buf, spaname) != 0)
 321                 return (SET_ERROR(EINVAL));
 322 
 323         ASSERT(dsl_pool_config_held(dp));
 324 
 325         err = dsl_dir_hold_obj(dp, dp->dp_root_dir_obj, NULL, tag, &dd);
 326         if (err != 0) {
 327                 return (err);
 328         }
 329 
 330         while (next != NULL) {
 331                 dsl_dir_t *child_ds;
 332                 err = getcomponent(next, buf, &nextnext);
 333                 if (err != 0)
 334                         break;
 335                 ASSERT(next[0] != '\0');
 336                 if (next[0] == '@')
 337                         break;
 338                 dprintf("looking up %s in obj%lld\n",
 339                     buf, dd->dd_phys->dd_child_dir_zapobj);
 340 
 341                 err = zap_lookup(dp->dp_meta_objset,
 342                     dd->dd_phys->dd_child_dir_zapobj,
 343                     buf, sizeof (ddobj), 1, &ddobj);
 344                 if (err != 0) {
 345                         if (err == ENOENT)
 346                                 err = 0;
 347                         break;
 348                 }
 349 
 350                 err = dsl_dir_hold_obj(dp, ddobj, buf, tag, &child_ds);
 351                 if (err != 0)
 352                         break;
 353                 dsl_dir_rele(dd, tag);
 354                 dd = child_ds;
 355                 next = nextnext;
 356         }
 357 
 358         if (err != 0) {
 359                 dsl_dir_rele(dd, tag);
 360                 return (err);
 361         }
 362 
 363         /*
 364          * It's an error if there's more than one component left, or
 365          * tailp==NULL and there's any component left.
 366          */
 367         if (next != NULL &&
 368             (tailp == NULL || (nextnext && nextnext[0] != '\0'))) {
 369                 /* bad path name */
 370                 dsl_dir_rele(dd, tag);
 371                 dprintf("next=%p (%s) tail=%p\n", next, next?next:"", tailp);
 372                 err = SET_ERROR(ENOENT);
 373         }
 374         if (tailp != NULL)
 375                 *tailp = next;
 376         *ddp = dd;
 377         return (err);
 378 }
 379 
 380 uint64_t
 381 dsl_dir_create_sync(dsl_pool_t *dp, dsl_dir_t *pds, const char *name,
 382     dmu_tx_t *tx)
 383 {
 384         objset_t *mos = dp->dp_meta_objset;
 385         uint64_t ddobj;
 386         dsl_dir_phys_t *ddphys;
 387         dmu_buf_t *dbuf;
 388 
 389         ddobj = dmu_object_alloc(mos, DMU_OT_DSL_DIR, 0,
 390             DMU_OT_DSL_DIR, sizeof (dsl_dir_phys_t), tx);
 391         if (pds) {
 392                 VERIFY(0 == zap_add(mos, pds->dd_phys->dd_child_dir_zapobj,
 393                     name, sizeof (uint64_t), 1, &ddobj, tx));
 394         } else {
 395                 /* it's the root dir */
 396                 VERIFY(0 == zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
 397                     DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, &ddobj, tx));
 398         }
 399         VERIFY(0 == dmu_bonus_hold(mos, ddobj, FTAG, &dbuf));
 400         dmu_buf_will_dirty(dbuf, tx);
 401         ddphys = dbuf->db_data;
 402 
 403         ddphys->dd_creation_time = gethrestime_sec();
 404         if (pds)
 405                 ddphys->dd_parent_obj = pds->dd_object;
 406         ddphys->dd_props_zapobj = zap_create(mos,
 407             DMU_OT_DSL_PROPS, DMU_OT_NONE, 0, tx);
 408         ddphys->dd_child_dir_zapobj = zap_create(mos,
 409             DMU_OT_DSL_DIR_CHILD_MAP, DMU_OT_NONE, 0, tx);
 410         if (spa_version(dp->dp_spa) >= SPA_VERSION_USED_BREAKDOWN)
 411                 ddphys->dd_flags |= DD_FLAG_USED_BREAKDOWN;
 412         dmu_buf_rele(dbuf, FTAG);
 413 
 414         return (ddobj);
 415 }
 416 
 417 boolean_t
 418 dsl_dir_is_clone(dsl_dir_t *dd)
 419 {
 420         return (dd->dd_phys->dd_origin_obj &&
 421             (dd->dd_pool->dp_origin_snap == NULL ||
 422             dd->dd_phys->dd_origin_obj !=
 423             dd->dd_pool->dp_origin_snap->ds_object));
 424 }
 425 
 426 void
 427 dsl_dir_stats(dsl_dir_t *dd, nvlist_t *nv)
 428 {
 429         mutex_enter(&dd->dd_lock);
 430         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
 431             dd->dd_phys->dd_used_bytes);
 432         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_QUOTA, dd->dd_phys->dd_quota);
 433         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_RESERVATION,
 434             dd->dd_phys->dd_reserved);
 435         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
 436             dd->dd_phys->dd_compressed_bytes == 0 ? 100 :
 437             (dd->dd_phys->dd_uncompressed_bytes * 100 /
 438             dd->dd_phys->dd_compressed_bytes));
 439         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALUSED,
 440             dd->dd_phys->dd_uncompressed_bytes);
 441         if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
 442                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDSNAP,
 443                     dd->dd_phys->dd_used_breakdown[DD_USED_SNAP]);
 444                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDDS,
 445                     dd->dd_phys->dd_used_breakdown[DD_USED_HEAD]);
 446                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDREFRESERV,
 447                     dd->dd_phys->dd_used_breakdown[DD_USED_REFRSRV]);
 448                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDCHILD,
 449                     dd->dd_phys->dd_used_breakdown[DD_USED_CHILD] +
 450                     dd->dd_phys->dd_used_breakdown[DD_USED_CHILD_RSRV]);
 451         }
 452         mutex_exit(&dd->dd_lock);
 453 
 454         if (dsl_dir_is_clone(dd)) {
 455                 dsl_dataset_t *ds;
 456                 char buf[MAXNAMELEN];
 457 
 458                 VERIFY0(dsl_dataset_hold_obj(dd->dd_pool,
 459                     dd->dd_phys->dd_origin_obj, FTAG, &ds));
 460                 dsl_dataset_name(ds, buf);
 461                 dsl_dataset_rele(ds, FTAG);
 462                 dsl_prop_nvlist_add_string(nv, ZFS_PROP_ORIGIN, buf);
 463         }
 464 }
 465 
 466 void
 467 dsl_dir_dirty(dsl_dir_t *dd, dmu_tx_t *tx)
 468 {
 469         dsl_pool_t *dp = dd->dd_pool;
 470 
 471         ASSERT(dd->dd_phys);
 472 
 473         if (txg_list_add(&dp->dp_dirty_dirs, dd, tx->tx_txg)) {
 474                 /* up the hold count until we can be written out */
 475                 dmu_buf_add_ref(dd->dd_dbuf, dd);
 476         }
 477 }
 478 
 479 static int64_t
 480 parent_delta(dsl_dir_t *dd, uint64_t used, int64_t delta)
 481 {
 482         uint64_t old_accounted = MAX(used, dd->dd_phys->dd_reserved);
 483         uint64_t new_accounted = MAX(used + delta, dd->dd_phys->dd_reserved);
 484         return (new_accounted - old_accounted);
 485 }
 486 
 487 void
 488 dsl_dir_sync(dsl_dir_t *dd, dmu_tx_t *tx)
 489 {
 490         ASSERT(dmu_tx_is_syncing(tx));
 491 
 492         mutex_enter(&dd->dd_lock);
 493         ASSERT0(dd->dd_tempreserved[tx->tx_txg&TXG_MASK]);
 494         dprintf_dd(dd, "txg=%llu towrite=%lluK\n", tx->tx_txg,
 495             dd->dd_space_towrite[tx->tx_txg&TXG_MASK] / 1024);
 496         dd->dd_space_towrite[tx->tx_txg&TXG_MASK] = 0;
 497         mutex_exit(&dd->dd_lock);
 498 
 499         /* release the hold from dsl_dir_dirty */
 500         dmu_buf_rele(dd->dd_dbuf, dd);
 501 }
 502 
 503 static uint64_t
 504 dsl_dir_space_towrite(dsl_dir_t *dd)
 505 {
 506         uint64_t space = 0;
 507         int i;
 508 
 509         ASSERT(MUTEX_HELD(&dd->dd_lock));
 510 
 511         for (i = 0; i < TXG_SIZE; i++) {
 512                 space += dd->dd_space_towrite[i&TXG_MASK];
 513                 ASSERT3U(dd->dd_space_towrite[i&TXG_MASK], >=, 0);
 514         }
 515         return (space);
 516 }
 517 
 518 /*
 519  * How much space would dd have available if ancestor had delta applied
 520  * to it?  If ondiskonly is set, we're only interested in what's
 521  * on-disk, not estimated pending changes.
 522  */
 523 uint64_t
 524 dsl_dir_space_available(dsl_dir_t *dd,
 525     dsl_dir_t *ancestor, int64_t delta, int ondiskonly)
 526 {
 527         uint64_t parentspace, myspace, quota, used;
 528 
 529         /*
 530          * If there are no restrictions otherwise, assume we have
 531          * unlimited space available.
 532          */
 533         quota = UINT64_MAX;
 534         parentspace = UINT64_MAX;
 535 
 536         if (dd->dd_parent != NULL) {
 537                 parentspace = dsl_dir_space_available(dd->dd_parent,
 538                     ancestor, delta, ondiskonly);
 539         }
 540 
 541         mutex_enter(&dd->dd_lock);
 542         if (dd->dd_phys->dd_quota != 0)
 543                 quota = dd->dd_phys->dd_quota;
 544         used = dd->dd_phys->dd_used_bytes;
 545         if (!ondiskonly)
 546                 used += dsl_dir_space_towrite(dd);
 547 
 548         if (dd->dd_parent == NULL) {
 549                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, FALSE);
 550                 quota = MIN(quota, poolsize);
 551         }
 552 
 553         if (dd->dd_phys->dd_reserved > used && parentspace != UINT64_MAX) {
 554                 /*
 555                  * We have some space reserved, in addition to what our
 556                  * parent gave us.
 557                  */
 558                 parentspace += dd->dd_phys->dd_reserved - used;
 559         }
 560 
 561         if (dd == ancestor) {
 562                 ASSERT(delta <= 0);
 563                 ASSERT(used >= -delta);
 564                 used += delta;
 565                 if (parentspace != UINT64_MAX)
 566                         parentspace -= delta;
 567         }
 568 
 569         if (used > quota) {
 570                 /* over quota */
 571                 myspace = 0;
 572         } else {
 573                 /*
 574                  * the lesser of the space provided by our parent and
 575                  * the space left in our quota
 576                  */
 577                 myspace = MIN(parentspace, quota - used);
 578         }
 579 
 580         mutex_exit(&dd->dd_lock);
 581 
 582         return (myspace);
 583 }
 584 
 585 struct tempreserve {
 586         list_node_t tr_node;
 587         dsl_dir_t *tr_ds;
 588         uint64_t tr_size;
 589 };
 590 
 591 static int
 592 dsl_dir_tempreserve_impl(dsl_dir_t *dd, uint64_t asize, boolean_t netfree,
 593     boolean_t ignorequota, boolean_t checkrefquota, list_t *tr_list,
 594     dmu_tx_t *tx, boolean_t first)
 595 {
 596         uint64_t txg = tx->tx_txg;
 597         uint64_t est_inflight, used_on_disk, quota, parent_rsrv;
 598         uint64_t deferred = 0;
 599         struct tempreserve *tr;
 600         int retval = EDQUOT;
 601         int txgidx = txg & TXG_MASK;
 602         int i;
 603         uint64_t ref_rsrv = 0;
 604 
 605         ASSERT3U(txg, !=, 0);
 606         ASSERT3S(asize, >, 0);
 607 
 608         mutex_enter(&dd->dd_lock);
 609 
 610         /*
 611          * Check against the dsl_dir's quota.  We don't add in the delta
 612          * when checking for over-quota because they get one free hit.
 613          */
 614         est_inflight = dsl_dir_space_towrite(dd);
 615         for (i = 0; i < TXG_SIZE; i++)
 616                 est_inflight += dd->dd_tempreserved[i];
 617         used_on_disk = dd->dd_phys->dd_used_bytes;
 618 
 619         /*
 620          * On the first iteration, fetch the dataset's used-on-disk and
 621          * refreservation values. Also, if checkrefquota is set, test if
 622          * allocating this space would exceed the dataset's refquota.
 623          */
 624         if (first && tx->tx_objset) {
 625                 int error;
 626                 dsl_dataset_t *ds = tx->tx_objset->os_dsl_dataset;
 627 
 628                 error = dsl_dataset_check_quota(ds, checkrefquota,
 629                     asize, est_inflight, &used_on_disk, &ref_rsrv);
 630                 if (error) {
 631                         mutex_exit(&dd->dd_lock);
 632                         return (error);
 633                 }
 634         }
 635 
 636         /*
 637          * If this transaction will result in a net free of space,
 638          * we want to let it through.
 639          */
 640         if (ignorequota || netfree || dd->dd_phys->dd_quota == 0)
 641                 quota = UINT64_MAX;
 642         else
 643                 quota = dd->dd_phys->dd_quota;
 644 
 645         /*
 646          * Adjust the quota against the actual pool size at the root
 647          * minus any outstanding deferred frees.
 648          * To ensure that it's possible to remove files from a full
 649          * pool without inducing transient overcommits, we throttle
 650          * netfree transactions against a quota that is slightly larger,
 651          * but still within the pool's allocation slop.  In cases where
 652          * we're very close to full, this will allow a steady trickle of
 653          * removes to get through.
 654          */
 655         if (dd->dd_parent == NULL) {
 656                 spa_t *spa = dd->dd_pool->dp_spa;
 657                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, netfree);
 658                 deferred = metaslab_class_get_deferred(spa_normal_class(spa));
 659                 if (poolsize - deferred < quota) {
 660                         quota = poolsize - deferred;
 661                         retval = ENOSPC;
 662                 }
 663         }
 664 
 665         /*
 666          * If they are requesting more space, and our current estimate
 667          * is over quota, they get to try again unless the actual
 668          * on-disk is over quota and there are no pending changes (which
 669          * may free up space for us).
 670          */
 671         if (used_on_disk + est_inflight >= quota) {
 672                 if (est_inflight > 0 || used_on_disk < quota ||
 673                     (retval == ENOSPC && used_on_disk < quota + deferred))
 674                         retval = ERESTART;
 675                 dprintf_dd(dd, "failing: used=%lluK inflight = %lluK "
 676                     "quota=%lluK tr=%lluK err=%d\n",
 677                     used_on_disk>>10, est_inflight>>10,
 678                     quota>>10, asize>>10, retval);
 679                 mutex_exit(&dd->dd_lock);
 680                 return (SET_ERROR(retval));
 681         }
 682 
 683         /* We need to up our estimated delta before dropping dd_lock */
 684         dd->dd_tempreserved[txgidx] += asize;
 685 
 686         parent_rsrv = parent_delta(dd, used_on_disk + est_inflight,
 687             asize - ref_rsrv);
 688         mutex_exit(&dd->dd_lock);
 689 
 690         tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 691         tr->tr_ds = dd;
 692         tr->tr_size = asize;
 693         list_insert_tail(tr_list, tr);
 694 
 695         /* see if it's OK with our parent */
 696         if (dd->dd_parent && parent_rsrv) {
 697                 boolean_t ismos = (dd->dd_phys->dd_head_dataset_obj == 0);
 698 
 699                 return (dsl_dir_tempreserve_impl(dd->dd_parent,
 700                     parent_rsrv, netfree, ismos, TRUE, tr_list, tx, FALSE));
 701         } else {
 702                 return (0);
 703         }
 704 }
 705 
 706 /*
 707  * Reserve space in this dsl_dir, to be used in this tx's txg.
 708  * After the space has been dirtied (and dsl_dir_willuse_space()
 709  * has been called), the reservation should be canceled, using
 710  * dsl_dir_tempreserve_clear().
 711  */
 712 int
 713 dsl_dir_tempreserve_space(dsl_dir_t *dd, uint64_t lsize, uint64_t asize,
 714     uint64_t fsize, uint64_t usize, void **tr_cookiep, dmu_tx_t *tx)
 715 {
 716         int err;
 717         list_t *tr_list;
 718 
 719         if (asize == 0) {
 720                 *tr_cookiep = NULL;
 721                 return (0);
 722         }
 723 
 724         tr_list = kmem_alloc(sizeof (list_t), KM_SLEEP);
 725         list_create(tr_list, sizeof (struct tempreserve),
 726             offsetof(struct tempreserve, tr_node));
 727         ASSERT3S(asize, >, 0);
 728         ASSERT3S(fsize, >=, 0);
 729 
 730         err = arc_tempreserve_space(lsize, tx->tx_txg);
 731         if (err == 0) {
 732                 struct tempreserve *tr;
 733 
 734                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 735                 tr->tr_size = lsize;
 736                 list_insert_tail(tr_list, tr);
 737         } else {
 738                 if (err == EAGAIN) {
 739                         /*
 740                          * If arc_memory_throttle() detected that pageout
 741                          * is running and we are low on memory, we delay new
 742                          * non-pageout transactions to give pageout an
 743                          * advantage.
 744                          *
 745                          * It is unfortunate to be delaying while the caller's
 746                          * locks are held.
 747                          */
 748                         txg_delay(dd->dd_pool, tx->tx_txg,
 749                             MSEC2NSEC(10), MSEC2NSEC(10));
 750                         err = SET_ERROR(ERESTART);
 751                 }
 752         }
 753 
 754         if (err == 0) {
 755                 err = dsl_dir_tempreserve_impl(dd, asize, fsize >= asize,
 756                     FALSE, asize > usize, tr_list, tx, TRUE);
 757         }
 758 
 759         if (err != 0)
 760                 dsl_dir_tempreserve_clear(tr_list, tx);
 761         else
 762                 *tr_cookiep = tr_list;
 763 
 764         return (err);
 765 }
 766 
 767 /*
 768  * Clear a temporary reservation that we previously made with
 769  * dsl_dir_tempreserve_space().
 770  */
 771 void
 772 dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
 773 {
 774         int txgidx = tx->tx_txg & TXG_MASK;
 775         list_t *tr_list = tr_cookie;
 776         struct tempreserve *tr;
 777 
 778         ASSERT3U(tx->tx_txg, !=, 0);
 779 
 780         if (tr_cookie == NULL)
 781                 return;
 782 
 783         while ((tr = list_head(tr_list)) != NULL) {
 784                 if (tr->tr_ds) {
 785                         mutex_enter(&tr->tr_ds->dd_lock);
 786                         ASSERT3U(tr->tr_ds->dd_tempreserved[txgidx], >=,
 787                             tr->tr_size);
 788                         tr->tr_ds->dd_tempreserved[txgidx] -= tr->tr_size;
 789                         mutex_exit(&tr->tr_ds->dd_lock);
 790                 } else {
 791                         arc_tempreserve_clear(tr->tr_size);
 792                 }
 793                 list_remove(tr_list, tr);
 794                 kmem_free(tr, sizeof (struct tempreserve));
 795         }
 796 
 797         kmem_free(tr_list, sizeof (list_t));
 798 }
 799 
 800 /*
 801  * This should be called from open context when we think we're going to write
 802  * or free space, for example when dirtying data. Be conservative; it's okay
 803  * to write less space or free more, but we don't want to write more or free
 804  * less than the amount specified.
 805  */
 806 void
 807 dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
 808 {
 809         int64_t parent_space;
 810         uint64_t est_used;
 811 
 812         mutex_enter(&dd->dd_lock);
 813         if (space > 0)
 814                 dd->dd_space_towrite[tx->tx_txg & TXG_MASK] += space;
 815 
 816         est_used = dsl_dir_space_towrite(dd) + dd->dd_phys->dd_used_bytes;
 817         parent_space = parent_delta(dd, est_used, space);
 818         mutex_exit(&dd->dd_lock);
 819 
 820         /* Make sure that we clean up dd_space_to* */
 821         dsl_dir_dirty(dd, tx);
 822 
 823         /* XXX this is potentially expensive and unnecessary... */
 824         if (parent_space && dd->dd_parent)
 825                 dsl_dir_willuse_space(dd->dd_parent, parent_space, tx);
 826 }
 827 
 828 /* call from syncing context when we actually write/free space for this dd */
 829 void
 830 dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
 831     int64_t used, int64_t compressed, int64_t uncompressed, dmu_tx_t *tx)
 832 {
 833         int64_t accounted_delta;
 834 
 835         /*
 836          * dsl_dataset_set_refreservation_sync_impl() calls this with
 837          * dd_lock held, so that it can atomically update
 838          * ds->ds_reserved and the dsl_dir accounting, so that
 839          * dsl_dataset_check_quota() can see dataset and dir accounting
 840          * consistently.
 841          */
 842         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
 843 
 844         ASSERT(dmu_tx_is_syncing(tx));
 845         ASSERT(type < DD_USED_NUM);
 846 
 847         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 848 
 849         if (needlock)
 850                 mutex_enter(&dd->dd_lock);
 851         accounted_delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, used);
 852         ASSERT(used >= 0 || dd->dd_phys->dd_used_bytes >= -used);
 853         ASSERT(compressed >= 0 ||
 854             dd->dd_phys->dd_compressed_bytes >= -compressed);
 855         ASSERT(uncompressed >= 0 ||
 856             dd->dd_phys->dd_uncompressed_bytes >= -uncompressed);
 857         dd->dd_phys->dd_used_bytes += used;
 858         dd->dd_phys->dd_uncompressed_bytes += uncompressed;
 859         dd->dd_phys->dd_compressed_bytes += compressed;
 860 
 861         if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
 862                 ASSERT(used > 0 ||
 863                     dd->dd_phys->dd_used_breakdown[type] >= -used);
 864                 dd->dd_phys->dd_used_breakdown[type] += used;
 865 #ifdef DEBUG
 866                 dd_used_t t;
 867                 uint64_t u = 0;
 868                 for (t = 0; t < DD_USED_NUM; t++)
 869                         u += dd->dd_phys->dd_used_breakdown[t];
 870                 ASSERT3U(u, ==, dd->dd_phys->dd_used_bytes);
 871 #endif
 872         }
 873         if (needlock)
 874                 mutex_exit(&dd->dd_lock);
 875 
 876         if (dd->dd_parent != NULL) {
 877                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
 878                     accounted_delta, compressed, uncompressed, tx);
 879                 dsl_dir_transfer_space(dd->dd_parent,
 880                     used - accounted_delta,
 881                     DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
 882         }
 883 }
 884 
 885 void
 886 dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
 887     dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
 888 {
 889         ASSERT(dmu_tx_is_syncing(tx));
 890         ASSERT(oldtype < DD_USED_NUM);
 891         ASSERT(newtype < DD_USED_NUM);
 892 
 893         if (delta == 0 || !(dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN))
 894                 return;
 895 
 896         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 897         mutex_enter(&dd->dd_lock);
 898         ASSERT(delta > 0 ?
 899             dd->dd_phys->dd_used_breakdown[oldtype] >= delta :
 900             dd->dd_phys->dd_used_breakdown[newtype] >= -delta);
 901         ASSERT(dd->dd_phys->dd_used_bytes >= ABS(delta));
 902         dd->dd_phys->dd_used_breakdown[oldtype] -= delta;
 903         dd->dd_phys->dd_used_breakdown[newtype] += delta;
 904         mutex_exit(&dd->dd_lock);
 905 }
 906 
 907 typedef struct dsl_dir_set_qr_arg {
 908         const char *ddsqra_name;
 909         zprop_source_t ddsqra_source;
 910         uint64_t ddsqra_value;
 911 } dsl_dir_set_qr_arg_t;
 912 
 913 static int
 914 dsl_dir_set_quota_check(void *arg, dmu_tx_t *tx)
 915 {
 916         dsl_dir_set_qr_arg_t *ddsqra = arg;
 917         dsl_pool_t *dp = dmu_tx_pool(tx);
 918         dsl_dataset_t *ds;
 919         int error;
 920         uint64_t towrite, newval;
 921 
 922         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
 923         if (error != 0)
 924                 return (error);
 925 
 926         error = dsl_prop_predict(ds->ds_dir, "quota",
 927             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
 928         if (error != 0) {
 929                 dsl_dataset_rele(ds, FTAG);
 930                 return (error);
 931         }
 932 
 933         if (newval == 0) {
 934                 dsl_dataset_rele(ds, FTAG);
 935                 return (0);
 936         }
 937 
 938         mutex_enter(&ds->ds_dir->dd_lock);
 939         /*
 940          * If we are doing the preliminary check in open context, and
 941          * there are pending changes, then don't fail it, since the
 942          * pending changes could under-estimate the amount of space to be
 943          * freed up.
 944          */
 945         towrite = dsl_dir_space_towrite(ds->ds_dir);
 946         if ((dmu_tx_is_syncing(tx) || towrite == 0) &&
 947             (newval < ds->ds_dir->dd_phys->dd_reserved ||
 948             newval < ds->ds_dir->dd_phys->dd_used_bytes + towrite)) {
 949                 error = SET_ERROR(ENOSPC);
 950         }
 951         mutex_exit(&ds->ds_dir->dd_lock);
 952         dsl_dataset_rele(ds, FTAG);
 953         return (error);
 954 }
 955 
 956 static void
 957 dsl_dir_set_quota_sync(void *arg, dmu_tx_t *tx)
 958 {
 959         dsl_dir_set_qr_arg_t *ddsqra = arg;
 960         dsl_pool_t *dp = dmu_tx_pool(tx);
 961         dsl_dataset_t *ds;
 962         uint64_t newval;
 963 
 964         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
 965 
 966         if (spa_version(dp->dp_spa) >= SPA_VERSION_RECVD_PROPS) {
 967                 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_QUOTA),
 968                     ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
 969                     &ddsqra->ddsqra_value, tx);
 970 
 971                 VERIFY0(dsl_prop_get_int_ds(ds,
 972                     zfs_prop_to_name(ZFS_PROP_QUOTA), &newval));
 973         } else {
 974                 newval = ddsqra->ddsqra_value;
 975                 spa_history_log_internal_ds(ds, "set", tx, "%s=%lld",
 976                     zfs_prop_to_name(ZFS_PROP_QUOTA), (longlong_t)newval);
 977         }
 978 
 979         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 980         mutex_enter(&ds->ds_dir->dd_lock);
 981         ds->ds_dir->dd_phys->dd_quota = newval;
 982         mutex_exit(&ds->ds_dir->dd_lock);
 983         dsl_dataset_rele(ds, FTAG);
 984 }
 985 
 986 int
 987 dsl_dir_set_quota(const char *ddname, zprop_source_t source, uint64_t quota)
 988 {
 989         dsl_dir_set_qr_arg_t ddsqra;
 990 
 991         ddsqra.ddsqra_name = ddname;
 992         ddsqra.ddsqra_source = source;
 993         ddsqra.ddsqra_value = quota;
 994 
 995         return (dsl_sync_task(ddname, dsl_dir_set_quota_check,
 996             dsl_dir_set_quota_sync, &ddsqra, 0));
 997 }
 998 
 999 int
1000 dsl_dir_set_reservation_check(void *arg, dmu_tx_t *tx)
1001 {
1002         dsl_dir_set_qr_arg_t *ddsqra = arg;
1003         dsl_pool_t *dp = dmu_tx_pool(tx);
1004         dsl_dataset_t *ds;
1005         dsl_dir_t *dd;
1006         uint64_t newval, used, avail;
1007         int error;
1008 
1009         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
1010         if (error != 0)
1011                 return (error);
1012         dd = ds->ds_dir;
1013 
1014         /*
1015          * If we are doing the preliminary check in open context, the
1016          * space estimates may be inaccurate.
1017          */
1018         if (!dmu_tx_is_syncing(tx)) {
1019                 dsl_dataset_rele(ds, FTAG);
1020                 return (0);
1021         }
1022 
1023         error = dsl_prop_predict(ds->ds_dir,
1024             zfs_prop_to_name(ZFS_PROP_RESERVATION),
1025             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
1026         if (error != 0) {
1027                 dsl_dataset_rele(ds, FTAG);
1028                 return (error);
1029         }
1030 
1031         mutex_enter(&dd->dd_lock);
1032         used = dd->dd_phys->dd_used_bytes;
1033         mutex_exit(&dd->dd_lock);
1034 
1035         if (dd->dd_parent) {
1036                 avail = dsl_dir_space_available(dd->dd_parent,
1037                     NULL, 0, FALSE);
1038         } else {
1039                 avail = dsl_pool_adjustedsize(dd->dd_pool, B_FALSE) - used;
1040         }
1041 
1042         if (MAX(used, newval) > MAX(used, dd->dd_phys->dd_reserved)) {
1043                 uint64_t delta = MAX(used, newval) -
1044                     MAX(used, dd->dd_phys->dd_reserved);
1045 
1046                 if (delta > avail ||
1047                     (dd->dd_phys->dd_quota > 0 &&
1048                     newval > dd->dd_phys->dd_quota))
1049                         error = SET_ERROR(ENOSPC);
1050         }
1051 
1052         dsl_dataset_rele(ds, FTAG);
1053         return (error);
1054 }
1055 
1056 void
1057 dsl_dir_set_reservation_sync_impl(dsl_dir_t *dd, uint64_t value, dmu_tx_t *tx)
1058 {
1059         uint64_t used;
1060         int64_t delta;
1061 
1062         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1063 
1064         mutex_enter(&dd->dd_lock);
1065         used = dd->dd_phys->dd_used_bytes;
1066         delta = MAX(used, value) - MAX(used, dd->dd_phys->dd_reserved);
1067         dd->dd_phys->dd_reserved = value;
1068 
1069         if (dd->dd_parent != NULL) {
1070                 /* Roll up this additional usage into our ancestors */
1071                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1072                     delta, 0, 0, tx);
1073         }
1074         mutex_exit(&dd->dd_lock);
1075 }
1076 
1077 
1078 static void
1079 dsl_dir_set_reservation_sync(void *arg, dmu_tx_t *tx)
1080 {
1081         dsl_dir_set_qr_arg_t *ddsqra = arg;
1082         dsl_pool_t *dp = dmu_tx_pool(tx);
1083         dsl_dataset_t *ds;
1084         uint64_t newval;
1085 
1086         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
1087 
1088         if (spa_version(dp->dp_spa) >= SPA_VERSION_RECVD_PROPS) {
1089                 dsl_prop_set_sync_impl(ds,
1090                     zfs_prop_to_name(ZFS_PROP_RESERVATION),
1091                     ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
1092                     &ddsqra->ddsqra_value, tx);
1093 
1094                 VERIFY0(dsl_prop_get_int_ds(ds,
1095                     zfs_prop_to_name(ZFS_PROP_RESERVATION), &newval));
1096         } else {
1097                 newval = ddsqra->ddsqra_value;
1098                 spa_history_log_internal_ds(ds, "set", tx, "%s=%lld",
1099                     zfs_prop_to_name(ZFS_PROP_RESERVATION),
1100                     (longlong_t)newval);
1101         }
1102 
1103         dsl_dir_set_reservation_sync_impl(ds->ds_dir, newval, tx);
1104         dsl_dataset_rele(ds, FTAG);
1105 }
1106 
1107 int
1108 dsl_dir_set_reservation(const char *ddname, zprop_source_t source,
1109     uint64_t reservation)
1110 {
1111         dsl_dir_set_qr_arg_t ddsqra;
1112 
1113         ddsqra.ddsqra_name = ddname;
1114         ddsqra.ddsqra_source = source;
1115         ddsqra.ddsqra_value = reservation;
1116 
1117         return (dsl_sync_task(ddname, dsl_dir_set_reservation_check,
1118             dsl_dir_set_reservation_sync, &ddsqra, 0));
1119 }
1120 
1121 static dsl_dir_t *
1122 closest_common_ancestor(dsl_dir_t *ds1, dsl_dir_t *ds2)
1123 {
1124         for (; ds1; ds1 = ds1->dd_parent) {
1125                 dsl_dir_t *dd;
1126                 for (dd = ds2; dd; dd = dd->dd_parent) {
1127                         if (ds1 == dd)
1128                                 return (dd);
1129                 }
1130         }
1131         return (NULL);
1132 }
1133 
1134 /*
1135  * If delta is applied to dd, how much of that delta would be applied to
1136  * ancestor?  Syncing context only.
1137  */
1138 static int64_t
1139 would_change(dsl_dir_t *dd, int64_t delta, dsl_dir_t *ancestor)
1140 {
1141         if (dd == ancestor)
1142                 return (delta);
1143 
1144         mutex_enter(&dd->dd_lock);
1145         delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, delta);
1146         mutex_exit(&dd->dd_lock);
1147         return (would_change(dd->dd_parent, delta, ancestor));
1148 }
1149 
1150 typedef struct dsl_dir_rename_arg {
1151         const char *ddra_oldname;
1152         const char *ddra_newname;
1153 } dsl_dir_rename_arg_t;
1154 
1155 /* ARGSUSED */
1156 static int
1157 dsl_valid_rename(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
1158 {
1159         int *deltap = arg;
1160         char namebuf[MAXNAMELEN];
1161 
1162         dsl_dataset_name(ds, namebuf);
1163 
1164         if (strlen(namebuf) + *deltap >= MAXNAMELEN)
1165                 return (SET_ERROR(ENAMETOOLONG));
1166         return (0);
1167 }
1168 
1169 static int
1170 dsl_dir_rename_check(void *arg, dmu_tx_t *tx)
1171 {
1172         dsl_dir_rename_arg_t *ddra = arg;
1173         dsl_pool_t *dp = dmu_tx_pool(tx);
1174         dsl_dir_t *dd, *newparent;
1175         const char *mynewname;
1176         int error;
1177         int delta = strlen(ddra->ddra_newname) - strlen(ddra->ddra_oldname);
1178 
1179         /* target dir should exist */
1180         error = dsl_dir_hold(dp, ddra->ddra_oldname, FTAG, &dd, NULL);
1181         if (error != 0)
1182                 return (error);
1183 
1184         /* new parent should exist */
1185         error = dsl_dir_hold(dp, ddra->ddra_newname, FTAG,
1186             &newparent, &mynewname);
1187         if (error != 0) {
1188                 dsl_dir_rele(dd, FTAG);
1189                 return (error);
1190         }
1191 
1192         /* can't rename to different pool */
1193         if (dd->dd_pool != newparent->dd_pool) {
1194                 dsl_dir_rele(newparent, FTAG);
1195                 dsl_dir_rele(dd, FTAG);
1196                 return (SET_ERROR(ENXIO));
1197         }
1198 
1199         /* new name should not already exist */
1200         if (mynewname == NULL) {
1201                 dsl_dir_rele(newparent, FTAG);
1202                 dsl_dir_rele(dd, FTAG);
1203                 return (SET_ERROR(EEXIST));
1204         }
1205 
1206         /* if the name length is growing, validate child name lengths */
1207         if (delta > 0) {
1208                 error = dmu_objset_find_dp(dp, dd->dd_object, dsl_valid_rename,
1209                     &delta, DS_FIND_CHILDREN | DS_FIND_SNAPSHOTS);
1210                 if (error != 0) {
1211                         dsl_dir_rele(newparent, FTAG);
1212                         dsl_dir_rele(dd, FTAG);
1213                         return (error);
1214                 }
1215         }
1216 
1217         if (newparent != dd->dd_parent) {
1218                 /* is there enough space? */
1219                 uint64_t myspace =
1220                     MAX(dd->dd_phys->dd_used_bytes, dd->dd_phys->dd_reserved);
1221 
1222                 /* no rename into our descendant */
1223                 if (closest_common_ancestor(dd, newparent) == dd) {
1224                         dsl_dir_rele(newparent, FTAG);
1225                         dsl_dir_rele(dd, FTAG);
1226                         return (SET_ERROR(EINVAL));
1227                 }
1228 
1229                 error = dsl_dir_transfer_possible(dd->dd_parent,
1230                     newparent, myspace);
1231                 if (error != 0) {
1232                         dsl_dir_rele(newparent, FTAG);
1233                         dsl_dir_rele(dd, FTAG);
1234                         return (error);
1235                 }
1236         }
1237 
1238         dsl_dir_rele(newparent, FTAG);
1239         dsl_dir_rele(dd, FTAG);
1240         return (0);
1241 }
1242 
1243 static void
1244 dsl_dir_rename_sync(void *arg, dmu_tx_t *tx)
1245 {
1246         dsl_dir_rename_arg_t *ddra = arg;
1247         dsl_pool_t *dp = dmu_tx_pool(tx);
1248         dsl_dir_t *dd, *newparent;
1249         const char *mynewname;
1250         int error;
1251         objset_t *mos = dp->dp_meta_objset;
1252 
1253         VERIFY0(dsl_dir_hold(dp, ddra->ddra_oldname, FTAG, &dd, NULL));
1254         VERIFY0(dsl_dir_hold(dp, ddra->ddra_newname, FTAG, &newparent,
1255             &mynewname));
1256 
1257         /* Log this before we change the name. */
1258         spa_history_log_internal_dd(dd, "rename", tx,
1259             "-> %s", ddra->ddra_newname);
1260 
1261         if (newparent != dd->dd_parent) {
1262                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
1263                     -dd->dd_phys->dd_used_bytes,
1264                     -dd->dd_phys->dd_compressed_bytes,
1265                     -dd->dd_phys->dd_uncompressed_bytes, tx);
1266                 dsl_dir_diduse_space(newparent, DD_USED_CHILD,
1267                     dd->dd_phys->dd_used_bytes,
1268                     dd->dd_phys->dd_compressed_bytes,
1269                     dd->dd_phys->dd_uncompressed_bytes, tx);
1270 
1271                 if (dd->dd_phys->dd_reserved > dd->dd_phys->dd_used_bytes) {
1272                         uint64_t unused_rsrv = dd->dd_phys->dd_reserved -
1273                             dd->dd_phys->dd_used_bytes;
1274 
1275                         dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1276                             -unused_rsrv, 0, 0, tx);
1277                         dsl_dir_diduse_space(newparent, DD_USED_CHILD_RSRV,
1278                             unused_rsrv, 0, 0, tx);
1279                 }
1280         }
1281 
1282         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1283 
1284         /* remove from old parent zapobj */
1285         error = zap_remove(mos, dd->dd_parent->dd_phys->dd_child_dir_zapobj,
1286             dd->dd_myname, tx);
1287         ASSERT0(error);
1288 
1289         (void) strcpy(dd->dd_myname, mynewname);
1290         dsl_dir_rele(dd->dd_parent, dd);
1291         dd->dd_phys->dd_parent_obj = newparent->dd_object;
1292         VERIFY0(dsl_dir_hold_obj(dp,
1293             newparent->dd_object, NULL, dd, &dd->dd_parent));
1294 
1295         /* add to new parent zapobj */
1296         VERIFY0(zap_add(mos, newparent->dd_phys->dd_child_dir_zapobj,
1297             dd->dd_myname, 8, 1, &dd->dd_object, tx));
1298 
1299         dsl_prop_notify_all(dd);
1300 
1301         dsl_dir_rele(newparent, FTAG);
1302         dsl_dir_rele(dd, FTAG);
1303 }
1304 
1305 int
1306 dsl_dir_rename(const char *oldname, const char *newname)
1307 {
1308         dsl_dir_rename_arg_t ddra;
1309 
1310         ddra.ddra_oldname = oldname;
1311         ddra.ddra_newname = newname;
1312 
1313         return (dsl_sync_task(oldname,
1314             dsl_dir_rename_check, dsl_dir_rename_sync, &ddra, 3));
1315 }
1316 
1317 int
1318 dsl_dir_transfer_possible(dsl_dir_t *sdd, dsl_dir_t *tdd, uint64_t space)
1319 {
1320         dsl_dir_t *ancestor;
1321         int64_t adelta;
1322         uint64_t avail;
1323 
1324         ancestor = closest_common_ancestor(sdd, tdd);
1325         adelta = would_change(sdd, -space, ancestor);
1326         avail = dsl_dir_space_available(tdd, ancestor, adelta, FALSE);
1327         if (avail < space)
1328                 return (SET_ERROR(ENOSPC));
1329 
1330         return (0);
1331 }
1332 
1333 timestruc_t
1334 dsl_dir_snap_cmtime(dsl_dir_t *dd)
1335 {
1336         timestruc_t t;
1337 
1338         mutex_enter(&dd->dd_lock);
1339         t = dd->dd_snap_cmtime;
1340         mutex_exit(&dd->dd_lock);
1341 
1342         return (t);
1343 }
1344 
1345 void
1346 dsl_dir_snap_cmtime_update(dsl_dir_t *dd)
1347 {
1348         timestruc_t t;
1349 
1350         gethrestime(&t);
1351         mutex_enter(&dd->dd_lock);
1352         dd->dd_snap_cmtime = t;
1353         mutex_exit(&dd->dd_lock);
1354 }