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_pool_t *tr_dp;
 588         dsl_dir_t *tr_ds;
 589         uint64_t tr_size;
 590 };
 591 
 592 static int
 593 dsl_dir_tempreserve_impl(dsl_dir_t *dd, uint64_t asize, boolean_t netfree,
 594     boolean_t ignorequota, boolean_t checkrefquota, list_t *tr_list,
 595     dmu_tx_t *tx, boolean_t first)
 596 {
 597         uint64_t txg = tx->tx_txg;
 598         uint64_t est_inflight, used_on_disk, quota, parent_rsrv;
 599         uint64_t deferred = 0;
 600         struct tempreserve *tr;
 601         int retval = EDQUOT;
 602         int txgidx = txg & TXG_MASK;
 603         int i;
 604         uint64_t ref_rsrv = 0;
 605 
 606         ASSERT3U(txg, !=, 0);
 607         ASSERT3S(asize, >, 0);
 608 
 609         mutex_enter(&dd->dd_lock);
 610 
 611         /*
 612          * Check against the dsl_dir's quota.  We don't add in the delta
 613          * when checking for over-quota because they get one free hit.
 614          */
 615         est_inflight = dsl_dir_space_towrite(dd);
 616         for (i = 0; i < TXG_SIZE; i++)
 617                 est_inflight += dd->dd_tempreserved[i];
 618         used_on_disk = dd->dd_phys->dd_used_bytes;
 619 
 620         /*
 621          * On the first iteration, fetch the dataset's used-on-disk and
 622          * refreservation values. Also, if checkrefquota is set, test if
 623          * allocating this space would exceed the dataset's refquota.
 624          */
 625         if (first && tx->tx_objset) {
 626                 int error;
 627                 dsl_dataset_t *ds = tx->tx_objset->os_dsl_dataset;
 628 
 629                 error = dsl_dataset_check_quota(ds, checkrefquota,
 630                     asize, est_inflight, &used_on_disk, &ref_rsrv);
 631                 if (error) {
 632                         mutex_exit(&dd->dd_lock);
 633                         return (error);
 634                 }
 635         }
 636 
 637         /*
 638          * If this transaction will result in a net free of space,
 639          * we want to let it through.
 640          */
 641         if (ignorequota || netfree || dd->dd_phys->dd_quota == 0)
 642                 quota = UINT64_MAX;
 643         else
 644                 quota = dd->dd_phys->dd_quota;
 645 
 646         /*
 647          * Adjust the quota against the actual pool size at the root
 648          * minus any outstanding deferred frees.
 649          * To ensure that it's possible to remove files from a full
 650          * pool without inducing transient overcommits, we throttle
 651          * netfree transactions against a quota that is slightly larger,
 652          * but still within the pool's allocation slop.  In cases where
 653          * we're very close to full, this will allow a steady trickle of
 654          * removes to get through.
 655          */
 656         if (dd->dd_parent == NULL) {
 657                 spa_t *spa = dd->dd_pool->dp_spa;
 658                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, netfree);
 659                 deferred = metaslab_class_get_deferred(spa_normal_class(spa));
 660                 if (poolsize - deferred < quota) {
 661                         quota = poolsize - deferred;
 662                         retval = ENOSPC;
 663                 }
 664         }
 665 
 666         /*
 667          * If they are requesting more space, and our current estimate
 668          * is over quota, they get to try again unless the actual
 669          * on-disk is over quota and there are no pending changes (which
 670          * may free up space for us).
 671          */
 672         if (used_on_disk + est_inflight >= quota) {
 673                 if (est_inflight > 0 || used_on_disk < quota ||
 674                     (retval == ENOSPC && used_on_disk < quota + deferred))
 675                         retval = ERESTART;
 676                 dprintf_dd(dd, "failing: used=%lluK inflight = %lluK "
 677                     "quota=%lluK tr=%lluK err=%d\n",
 678                     used_on_disk>>10, est_inflight>>10,
 679                     quota>>10, asize>>10, retval);
 680                 mutex_exit(&dd->dd_lock);
 681                 return (SET_ERROR(retval));
 682         }
 683 
 684         /* We need to up our estimated delta before dropping dd_lock */
 685         dd->dd_tempreserved[txgidx] += asize;
 686 
 687         parent_rsrv = parent_delta(dd, used_on_disk + est_inflight,
 688             asize - ref_rsrv);
 689         mutex_exit(&dd->dd_lock);
 690 
 691         tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 692         tr->tr_ds = dd;
 693         tr->tr_size = asize;
 694         list_insert_tail(tr_list, tr);
 695 
 696         /* see if it's OK with our parent */
 697         if (dd->dd_parent && parent_rsrv) {
 698                 boolean_t ismos = (dd->dd_phys->dd_head_dataset_obj == 0);
 699 
 700                 return (dsl_dir_tempreserve_impl(dd->dd_parent,
 701                     parent_rsrv, netfree, ismos, TRUE, tr_list, tx, FALSE));
 702         } else {
 703                 return (0);
 704         }
 705 }
 706 
 707 /*
 708  * Reserve space in this dsl_dir, to be used in this tx's txg.
 709  * After the space has been dirtied (and dsl_dir_willuse_space()
 710  * has been called), the reservation should be canceled, using
 711  * dsl_dir_tempreserve_clear().
 712  */
 713 int
 714 dsl_dir_tempreserve_space(dsl_dir_t *dd, uint64_t lsize, uint64_t asize,
 715     uint64_t fsize, uint64_t usize, void **tr_cookiep, dmu_tx_t *tx)
 716 {
 717         int err;
 718         list_t *tr_list;
 719 
 720         if (asize == 0) {
 721                 *tr_cookiep = NULL;
 722                 return (0);
 723         }
 724 
 725         tr_list = kmem_alloc(sizeof (list_t), KM_SLEEP);
 726         list_create(tr_list, sizeof (struct tempreserve),
 727             offsetof(struct tempreserve, tr_node));
 728         ASSERT3S(asize, >, 0);
 729         ASSERT3S(fsize, >=, 0);
 730 
 731         err = arc_tempreserve_space(lsize, tx->tx_txg);
 732         if (err == 0) {
 733                 struct tempreserve *tr;
 734 
 735                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 736                 tr->tr_size = lsize;
 737                 list_insert_tail(tr_list, tr);
 738 
 739                 err = dsl_pool_tempreserve_space(dd->dd_pool, asize, tx);
 740         } else {
 741                 if (err == EAGAIN) {
 742                         txg_delay(dd->dd_pool, tx->tx_txg,
 743                             MSEC2NSEC(10), MSEC2NSEC(10));
 744                         err = SET_ERROR(ERESTART);
 745                 }
 746                 dsl_pool_memory_pressure(dd->dd_pool);
 747         }
 748 
 749         if (err == 0) {
 750                 struct tempreserve *tr;
 751 
 752                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 753                 tr->tr_dp = dd->dd_pool;
 754                 tr->tr_size = asize;
 755                 list_insert_tail(tr_list, tr);
 756 
 757                 err = dsl_dir_tempreserve_impl(dd, asize, fsize >= asize,
 758                     FALSE, asize > usize, tr_list, tx, TRUE);
 759         }
 760 
 761         if (err != 0)
 762                 dsl_dir_tempreserve_clear(tr_list, tx);
 763         else
 764                 *tr_cookiep = tr_list;
 765 
 766         return (err);
 767 }
 768 
 769 /*
 770  * Clear a temporary reservation that we previously made with
 771  * dsl_dir_tempreserve_space().
 772  */
 773 void
 774 dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
 775 {
 776         int txgidx = tx->tx_txg & TXG_MASK;
 777         list_t *tr_list = tr_cookie;
 778         struct tempreserve *tr;
 779 
 780         ASSERT3U(tx->tx_txg, !=, 0);
 781 
 782         if (tr_cookie == NULL)
 783                 return;
 784 
 785         while (tr = list_head(tr_list)) {
 786                 if (tr->tr_dp) {
 787                         dsl_pool_tempreserve_clear(tr->tr_dp, tr->tr_size, tx);
 788                 } else if (tr->tr_ds) {
 789                         mutex_enter(&tr->tr_ds->dd_lock);
 790                         ASSERT3U(tr->tr_ds->dd_tempreserved[txgidx], >=,
 791                             tr->tr_size);
 792                         tr->tr_ds->dd_tempreserved[txgidx] -= tr->tr_size;
 793                         mutex_exit(&tr->tr_ds->dd_lock);
 794                 } else {
 795                         arc_tempreserve_clear(tr->tr_size);
 796                 }
 797                 list_remove(tr_list, tr);
 798                 kmem_free(tr, sizeof (struct tempreserve));
 799         }
 800 
 801         kmem_free(tr_list, sizeof (list_t));
 802 }
 803 
 804 static void
 805 dsl_dir_willuse_space_impl(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
 806 {
 807         int64_t parent_space;
 808         uint64_t est_used;
 809 
 810         mutex_enter(&dd->dd_lock);
 811         if (space > 0)
 812                 dd->dd_space_towrite[tx->tx_txg & TXG_MASK] += space;
 813 
 814         est_used = dsl_dir_space_towrite(dd) + dd->dd_phys->dd_used_bytes;
 815         parent_space = parent_delta(dd, est_used, space);
 816         mutex_exit(&dd->dd_lock);
 817 
 818         /* Make sure that we clean up dd_space_to* */
 819         dsl_dir_dirty(dd, tx);
 820 
 821         /* XXX this is potentially expensive and unnecessary... */
 822         if (parent_space && dd->dd_parent)
 823                 dsl_dir_willuse_space_impl(dd->dd_parent, parent_space, tx);
 824 }
 825 
 826 /*
 827  * Call in open context when we think we're going to write/free space,
 828  * eg. when dirtying data.  Be conservative (ie. OK to write less than
 829  * this or free more than this, but don't write more or free less).
 830  */
 831 void
 832 dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
 833 {
 834         dsl_pool_willuse_space(dd->dd_pool, space, tx);
 835         dsl_dir_willuse_space_impl(dd, space, tx);
 836 }
 837 
 838 /* call from syncing context when we actually write/free space for this dd */
 839 void
 840 dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
 841     int64_t used, int64_t compressed, int64_t uncompressed, dmu_tx_t *tx)
 842 {
 843         int64_t accounted_delta;
 844         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
 845 
 846         ASSERT(dmu_tx_is_syncing(tx));
 847         ASSERT(type < DD_USED_NUM);
 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         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 858         dd->dd_phys->dd_used_bytes += used;
 859         dd->dd_phys->dd_uncompressed_bytes += uncompressed;
 860         dd->dd_phys->dd_compressed_bytes += compressed;
 861 
 862         if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
 863                 ASSERT(used > 0 ||
 864                     dd->dd_phys->dd_used_breakdown[type] >= -used);
 865                 dd->dd_phys->dd_used_breakdown[type] += used;
 866 #ifdef DEBUG
 867                 dd_used_t t;
 868                 uint64_t u = 0;
 869                 for (t = 0; t < DD_USED_NUM; t++)
 870                         u += dd->dd_phys->dd_used_breakdown[t];
 871                 ASSERT3U(u, ==, dd->dd_phys->dd_used_bytes);
 872 #endif
 873         }
 874         if (needlock)
 875                 mutex_exit(&dd->dd_lock);
 876 
 877         if (dd->dd_parent != NULL) {
 878                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
 879                     accounted_delta, compressed, uncompressed, tx);
 880                 dsl_dir_transfer_space(dd->dd_parent,
 881                     used - accounted_delta,
 882                     DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
 883         }
 884 }
 885 
 886 void
 887 dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
 888     dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
 889 {
 890         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
 891 
 892         ASSERT(dmu_tx_is_syncing(tx));
 893         ASSERT(oldtype < DD_USED_NUM);
 894         ASSERT(newtype < DD_USED_NUM);
 895 
 896         if (delta == 0 || !(dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN))
 897                 return;
 898 
 899         if (needlock)
 900                 mutex_enter(&dd->dd_lock);
 901         ASSERT(delta > 0 ?
 902             dd->dd_phys->dd_used_breakdown[oldtype] >= delta :
 903             dd->dd_phys->dd_used_breakdown[newtype] >= -delta);
 904         ASSERT(dd->dd_phys->dd_used_bytes >= ABS(delta));
 905         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 906         dd->dd_phys->dd_used_breakdown[oldtype] -= delta;
 907         dd->dd_phys->dd_used_breakdown[newtype] += delta;
 908         if (needlock)
 909                 mutex_exit(&dd->dd_lock);
 910 }
 911 
 912 typedef struct dsl_dir_set_qr_arg {
 913         const char *ddsqra_name;
 914         zprop_source_t ddsqra_source;
 915         uint64_t ddsqra_value;
 916 } dsl_dir_set_qr_arg_t;
 917 
 918 static int
 919 dsl_dir_set_quota_check(void *arg, dmu_tx_t *tx)
 920 {
 921         dsl_dir_set_qr_arg_t *ddsqra = arg;
 922         dsl_pool_t *dp = dmu_tx_pool(tx);
 923         dsl_dataset_t *ds;
 924         int error;
 925         uint64_t towrite, newval;
 926 
 927         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
 928         if (error != 0)
 929                 return (error);
 930 
 931         error = dsl_prop_predict(ds->ds_dir, "quota",
 932             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
 933         if (error != 0) {
 934                 dsl_dataset_rele(ds, FTAG);
 935                 return (error);
 936         }
 937 
 938         if (newval == 0) {
 939                 dsl_dataset_rele(ds, FTAG);
 940                 return (0);
 941         }
 942 
 943         mutex_enter(&ds->ds_dir->dd_lock);
 944         /*
 945          * If we are doing the preliminary check in open context, and
 946          * there are pending changes, then don't fail it, since the
 947          * pending changes could under-estimate the amount of space to be
 948          * freed up.
 949          */
 950         towrite = dsl_dir_space_towrite(ds->ds_dir);
 951         if ((dmu_tx_is_syncing(tx) || towrite == 0) &&
 952             (newval < ds->ds_dir->dd_phys->dd_reserved ||
 953             newval < ds->ds_dir->dd_phys->dd_used_bytes + towrite)) {
 954                 error = SET_ERROR(ENOSPC);
 955         }
 956         mutex_exit(&ds->ds_dir->dd_lock);
 957         dsl_dataset_rele(ds, FTAG);
 958         return (error);
 959 }
 960 
 961 static void
 962 dsl_dir_set_quota_sync(void *arg, dmu_tx_t *tx)
 963 {
 964         dsl_dir_set_qr_arg_t *ddsqra = arg;
 965         dsl_pool_t *dp = dmu_tx_pool(tx);
 966         dsl_dataset_t *ds;
 967         uint64_t newval;
 968 
 969         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
 970 
 971         if (spa_version(dp->dp_spa) >= SPA_VERSION_RECVD_PROPS) {
 972                 dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_QUOTA),
 973                     ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
 974                     &ddsqra->ddsqra_value, tx);
 975 
 976                 VERIFY0(dsl_prop_get_int_ds(ds,
 977                     zfs_prop_to_name(ZFS_PROP_QUOTA), &newval));
 978         } else {
 979                 newval = ddsqra->ddsqra_value;
 980                 spa_history_log_internal_ds(ds, "set", tx, "%s=%lld",
 981                     zfs_prop_to_name(ZFS_PROP_QUOTA), (longlong_t)newval);
 982         }
 983 
 984         dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
 985         mutex_enter(&ds->ds_dir->dd_lock);
 986         ds->ds_dir->dd_phys->dd_quota = newval;
 987         mutex_exit(&ds->ds_dir->dd_lock);
 988         dsl_dataset_rele(ds, FTAG);
 989 }
 990 
 991 int
 992 dsl_dir_set_quota(const char *ddname, zprop_source_t source, uint64_t quota)
 993 {
 994         dsl_dir_set_qr_arg_t ddsqra;
 995 
 996         ddsqra.ddsqra_name = ddname;
 997         ddsqra.ddsqra_source = source;
 998         ddsqra.ddsqra_value = quota;
 999 
1000         return (dsl_sync_task(ddname, dsl_dir_set_quota_check,
1001             dsl_dir_set_quota_sync, &ddsqra, 0));
1002 }
1003 
1004 int
1005 dsl_dir_set_reservation_check(void *arg, dmu_tx_t *tx)
1006 {
1007         dsl_dir_set_qr_arg_t *ddsqra = arg;
1008         dsl_pool_t *dp = dmu_tx_pool(tx);
1009         dsl_dataset_t *ds;
1010         dsl_dir_t *dd;
1011         uint64_t newval, used, avail;
1012         int error;
1013 
1014         error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
1015         if (error != 0)
1016                 return (error);
1017         dd = ds->ds_dir;
1018 
1019         /*
1020          * If we are doing the preliminary check in open context, the
1021          * space estimates may be inaccurate.
1022          */
1023         if (!dmu_tx_is_syncing(tx)) {
1024                 dsl_dataset_rele(ds, FTAG);
1025                 return (0);
1026         }
1027 
1028         error = dsl_prop_predict(ds->ds_dir,
1029             zfs_prop_to_name(ZFS_PROP_RESERVATION),
1030             ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
1031         if (error != 0) {
1032                 dsl_dataset_rele(ds, FTAG);
1033                 return (error);
1034         }
1035 
1036         mutex_enter(&dd->dd_lock);
1037         used = dd->dd_phys->dd_used_bytes;
1038         mutex_exit(&dd->dd_lock);
1039 
1040         if (dd->dd_parent) {
1041                 avail = dsl_dir_space_available(dd->dd_parent,
1042                     NULL, 0, FALSE);
1043         } else {
1044                 avail = dsl_pool_adjustedsize(dd->dd_pool, B_FALSE) - used;
1045         }
1046 
1047         if (MAX(used, newval) > MAX(used, dd->dd_phys->dd_reserved)) {
1048                 uint64_t delta = MAX(used, newval) -
1049                     MAX(used, dd->dd_phys->dd_reserved);
1050 
1051                 if (delta > avail ||
1052                     (dd->dd_phys->dd_quota > 0 &&
1053                     newval > dd->dd_phys->dd_quota))
1054                         error = SET_ERROR(ENOSPC);
1055         }
1056 
1057         dsl_dataset_rele(ds, FTAG);
1058         return (error);
1059 }
1060 
1061 void
1062 dsl_dir_set_reservation_sync_impl(dsl_dir_t *dd, uint64_t value, dmu_tx_t *tx)
1063 {
1064         uint64_t used;
1065         int64_t delta;
1066 
1067         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1068 
1069         mutex_enter(&dd->dd_lock);
1070         used = dd->dd_phys->dd_used_bytes;
1071         delta = MAX(used, value) - MAX(used, dd->dd_phys->dd_reserved);
1072         dd->dd_phys->dd_reserved = value;
1073 
1074         if (dd->dd_parent != NULL) {
1075                 /* Roll up this additional usage into our ancestors */
1076                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1077                     delta, 0, 0, tx);
1078         }
1079         mutex_exit(&dd->dd_lock);
1080 }
1081 
1082 
1083 static void
1084 dsl_dir_set_reservation_sync(void *arg, dmu_tx_t *tx)
1085 {
1086         dsl_dir_set_qr_arg_t *ddsqra = arg;
1087         dsl_pool_t *dp = dmu_tx_pool(tx);
1088         dsl_dataset_t *ds;
1089         uint64_t newval;
1090 
1091         VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
1092 
1093         if (spa_version(dp->dp_spa) >= SPA_VERSION_RECVD_PROPS) {
1094                 dsl_prop_set_sync_impl(ds,
1095                     zfs_prop_to_name(ZFS_PROP_RESERVATION),
1096                     ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
1097                     &ddsqra->ddsqra_value, tx);
1098 
1099                 VERIFY0(dsl_prop_get_int_ds(ds,
1100                     zfs_prop_to_name(ZFS_PROP_RESERVATION), &newval));
1101         } else {
1102                 newval = ddsqra->ddsqra_value;
1103                 spa_history_log_internal_ds(ds, "set", tx, "%s=%lld",
1104                     zfs_prop_to_name(ZFS_PROP_RESERVATION),
1105                     (longlong_t)newval);
1106         }
1107 
1108         dsl_dir_set_reservation_sync_impl(ds->ds_dir, newval, tx);
1109         dsl_dataset_rele(ds, FTAG);
1110 }
1111 
1112 int
1113 dsl_dir_set_reservation(const char *ddname, zprop_source_t source,
1114     uint64_t reservation)
1115 {
1116         dsl_dir_set_qr_arg_t ddsqra;
1117 
1118         ddsqra.ddsqra_name = ddname;
1119         ddsqra.ddsqra_source = source;
1120         ddsqra.ddsqra_value = reservation;
1121 
1122         return (dsl_sync_task(ddname, dsl_dir_set_reservation_check,
1123             dsl_dir_set_reservation_sync, &ddsqra, 0));
1124 }
1125 
1126 static dsl_dir_t *
1127 closest_common_ancestor(dsl_dir_t *ds1, dsl_dir_t *ds2)
1128 {
1129         for (; ds1; ds1 = ds1->dd_parent) {
1130                 dsl_dir_t *dd;
1131                 for (dd = ds2; dd; dd = dd->dd_parent) {
1132                         if (ds1 == dd)
1133                                 return (dd);
1134                 }
1135         }
1136         return (NULL);
1137 }
1138 
1139 /*
1140  * If delta is applied to dd, how much of that delta would be applied to
1141  * ancestor?  Syncing context only.
1142  */
1143 static int64_t
1144 would_change(dsl_dir_t *dd, int64_t delta, dsl_dir_t *ancestor)
1145 {
1146         if (dd == ancestor)
1147                 return (delta);
1148 
1149         mutex_enter(&dd->dd_lock);
1150         delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, delta);
1151         mutex_exit(&dd->dd_lock);
1152         return (would_change(dd->dd_parent, delta, ancestor));
1153 }
1154 
1155 typedef struct dsl_dir_rename_arg {
1156         const char *ddra_oldname;
1157         const char *ddra_newname;
1158 } dsl_dir_rename_arg_t;
1159 
1160 /* ARGSUSED */
1161 static int
1162 dsl_valid_rename(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
1163 {
1164         int *deltap = arg;
1165         char namebuf[MAXNAMELEN];
1166 
1167         dsl_dataset_name(ds, namebuf);
1168 
1169         if (strlen(namebuf) + *deltap >= MAXNAMELEN)
1170                 return (SET_ERROR(ENAMETOOLONG));
1171         return (0);
1172 }
1173 
1174 static int
1175 dsl_dir_rename_check(void *arg, dmu_tx_t *tx)
1176 {
1177         dsl_dir_rename_arg_t *ddra = arg;
1178         dsl_pool_t *dp = dmu_tx_pool(tx);
1179         dsl_dir_t *dd, *newparent;
1180         const char *mynewname;
1181         int error;
1182         int delta = strlen(ddra->ddra_newname) - strlen(ddra->ddra_oldname);
1183 
1184         /* target dir should exist */
1185         error = dsl_dir_hold(dp, ddra->ddra_oldname, FTAG, &dd, NULL);
1186         if (error != 0)
1187                 return (error);
1188 
1189         /* new parent should exist */
1190         error = dsl_dir_hold(dp, ddra->ddra_newname, FTAG,
1191             &newparent, &mynewname);
1192         if (error != 0) {
1193                 dsl_dir_rele(dd, FTAG);
1194                 return (error);
1195         }
1196 
1197         /* can't rename to different pool */
1198         if (dd->dd_pool != newparent->dd_pool) {
1199                 dsl_dir_rele(newparent, FTAG);
1200                 dsl_dir_rele(dd, FTAG);
1201                 return (SET_ERROR(ENXIO));
1202         }
1203 
1204         /* new name should not already exist */
1205         if (mynewname == NULL) {
1206                 dsl_dir_rele(newparent, FTAG);
1207                 dsl_dir_rele(dd, FTAG);
1208                 return (SET_ERROR(EEXIST));
1209         }
1210 
1211         /* if the name length is growing, validate child name lengths */
1212         if (delta > 0) {
1213                 error = dmu_objset_find_dp(dp, dd->dd_object, dsl_valid_rename,
1214                     &delta, DS_FIND_CHILDREN | DS_FIND_SNAPSHOTS);
1215                 if (error != 0) {
1216                         dsl_dir_rele(newparent, FTAG);
1217                         dsl_dir_rele(dd, FTAG);
1218                         return (error);
1219                 }
1220         }
1221 
1222         if (newparent != dd->dd_parent) {
1223                 /* is there enough space? */
1224                 uint64_t myspace =
1225                     MAX(dd->dd_phys->dd_used_bytes, dd->dd_phys->dd_reserved);
1226 
1227                 /* no rename into our descendant */
1228                 if (closest_common_ancestor(dd, newparent) == dd) {
1229                         dsl_dir_rele(newparent, FTAG);
1230                         dsl_dir_rele(dd, FTAG);
1231                         return (SET_ERROR(EINVAL));
1232                 }
1233 
1234                 error = dsl_dir_transfer_possible(dd->dd_parent,
1235                     newparent, myspace);
1236                 if (error != 0) {
1237                         dsl_dir_rele(newparent, FTAG);
1238                         dsl_dir_rele(dd, FTAG);
1239                         return (error);
1240                 }
1241         }
1242 
1243         dsl_dir_rele(newparent, FTAG);
1244         dsl_dir_rele(dd, FTAG);
1245         return (0);
1246 }
1247 
1248 static void
1249 dsl_dir_rename_sync(void *arg, dmu_tx_t *tx)
1250 {
1251         dsl_dir_rename_arg_t *ddra = arg;
1252         dsl_pool_t *dp = dmu_tx_pool(tx);
1253         dsl_dir_t *dd, *newparent;
1254         const char *mynewname;
1255         int error;
1256         objset_t *mos = dp->dp_meta_objset;
1257 
1258         VERIFY0(dsl_dir_hold(dp, ddra->ddra_oldname, FTAG, &dd, NULL));
1259         VERIFY0(dsl_dir_hold(dp, ddra->ddra_newname, FTAG, &newparent,
1260             &mynewname));
1261 
1262         /* Log this before we change the name. */
1263         spa_history_log_internal_dd(dd, "rename", tx,
1264             "-> %s", ddra->ddra_newname);
1265 
1266         if (newparent != dd->dd_parent) {
1267                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
1268                     -dd->dd_phys->dd_used_bytes,
1269                     -dd->dd_phys->dd_compressed_bytes,
1270                     -dd->dd_phys->dd_uncompressed_bytes, tx);
1271                 dsl_dir_diduse_space(newparent, DD_USED_CHILD,
1272                     dd->dd_phys->dd_used_bytes,
1273                     dd->dd_phys->dd_compressed_bytes,
1274                     dd->dd_phys->dd_uncompressed_bytes, tx);
1275 
1276                 if (dd->dd_phys->dd_reserved > dd->dd_phys->dd_used_bytes) {
1277                         uint64_t unused_rsrv = dd->dd_phys->dd_reserved -
1278                             dd->dd_phys->dd_used_bytes;
1279 
1280                         dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1281                             -unused_rsrv, 0, 0, tx);
1282                         dsl_dir_diduse_space(newparent, DD_USED_CHILD_RSRV,
1283                             unused_rsrv, 0, 0, tx);
1284                 }
1285         }
1286 
1287         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1288 
1289         /* remove from old parent zapobj */
1290         error = zap_remove(mos, dd->dd_parent->dd_phys->dd_child_dir_zapobj,
1291             dd->dd_myname, tx);
1292         ASSERT0(error);
1293 
1294         (void) strcpy(dd->dd_myname, mynewname);
1295         dsl_dir_rele(dd->dd_parent, dd);
1296         dd->dd_phys->dd_parent_obj = newparent->dd_object;
1297         VERIFY0(dsl_dir_hold_obj(dp,
1298             newparent->dd_object, NULL, dd, &dd->dd_parent));
1299 
1300         /* add to new parent zapobj */
1301         VERIFY0(zap_add(mos, newparent->dd_phys->dd_child_dir_zapobj,
1302             dd->dd_myname, 8, 1, &dd->dd_object, tx));
1303 
1304         dsl_prop_notify_all(dd);
1305 
1306         dsl_dir_rele(newparent, FTAG);
1307         dsl_dir_rele(dd, FTAG);
1308 }
1309 
1310 int
1311 dsl_dir_rename(const char *oldname, const char *newname)
1312 {
1313         dsl_dir_rename_arg_t ddra;
1314 
1315         ddra.ddra_oldname = oldname;
1316         ddra.ddra_newname = newname;
1317 
1318         return (dsl_sync_task(oldname,
1319             dsl_dir_rename_check, dsl_dir_rename_sync, &ddra, 3));
1320 }
1321 
1322 int
1323 dsl_dir_transfer_possible(dsl_dir_t *sdd, dsl_dir_t *tdd, uint64_t space)
1324 {
1325         dsl_dir_t *ancestor;
1326         int64_t adelta;
1327         uint64_t avail;
1328 
1329         ancestor = closest_common_ancestor(sdd, tdd);
1330         adelta = would_change(sdd, -space, ancestor);
1331         avail = dsl_dir_space_available(tdd, ancestor, adelta, FALSE);
1332         if (avail < space)
1333                 return (SET_ERROR(ENOSPC));
1334 
1335         return (0);
1336 }
1337 
1338 timestruc_t
1339 dsl_dir_snap_cmtime(dsl_dir_t *dd)
1340 {
1341         timestruc_t t;
1342 
1343         mutex_enter(&dd->dd_lock);
1344         t = dd->dd_snap_cmtime;
1345         mutex_exit(&dd->dd_lock);
1346 
1347         return (t);
1348 }
1349 
1350 void
1351 dsl_dir_snap_cmtime_update(dsl_dir_t *dd)
1352 {
1353         timestruc_t t;
1354 
1355         gethrestime(&t);
1356         mutex_enter(&dd->dd_lock);
1357         dd->dd_snap_cmtime = t;
1358         mutex_exit(&dd->dd_lock);
1359 }