sys/cddl/contrib/opensolaris/uts/common/fs/zfs/dsl_dir.c

   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 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #include <sys/dmu.h>
  27 #include <sys/dmu_objset.h>
  28 #include <sys/dmu_tx.h>
  29 #include <sys/dsl_dataset.h>
  30 #include <sys/dsl_dir.h>
  31 #include <sys/dsl_prop.h>
  32 #include <sys/dsl_synctask.h>
  33 #include <sys/dsl_deleg.h>
  34 #include <sys/spa.h>
  35 #include <sys/zap.h>
  36 #include <sys/zio.h>
  37 #include <sys/arc.h>
  38 #include <sys/sunddi.h>
  39 #include "zfs_namecheck.h"
  40
  41 static uint64_t dsl_dir_space_towrite(dsl_dir_t *dd);
  42 static void dsl_dir_set_reservation_sync(void *arg1, void *arg2,
  43     cred_t *cr, dmu_tx_t *tx);
  44
  45
  46 /* ARGSUSED */
  47 static void
  48 dsl_dir_evict(dmu_buf_t *db, void *arg)
  49 {
  50         dsl_dir_t *dd = arg;
  51         dsl_pool_t *dp = dd->dd_pool;
  52         int t;
  53
  54         for (t = 0; t < TXG_SIZE; t++) {
  55                 ASSERT(!txg_list_member(&dp->dp_dirty_dirs, dd, t));
  56                 ASSERT(dd->dd_tempreserved[t] == 0);
  57                 ASSERT(dd->dd_space_towrite[t] == 0);
  58         }
  59
  60         if (dd->dd_parent)
  61                 dsl_dir_close(dd->dd_parent, dd);
  62
  63         spa_close(dd->dd_pool->dp_spa, dd);
  64
  65         /*
  66          * The props callback list should be empty since they hold the
  67          * dir open.
  68          */
  69         list_destroy(&dd->dd_prop_cbs);
  70         mutex_destroy(&dd->dd_lock);
  71         kmem_free(dd, sizeof (dsl_dir_t));
  72 }
  73
  74 int
  75 dsl_dir_open_obj(dsl_pool_t *dp, uint64_t ddobj,
  76     const char *tail, void *tag, dsl_dir_t **ddp)
  77 {
  78         dmu_buf_t *dbuf;
  79         dsl_dir_t *dd;
  80         int err;
  81
  82         ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock) ||
  83             dsl_pool_sync_context(dp));
  84
  85         err = dmu_bonus_hold(dp->dp_meta_objset, ddobj, tag, &dbuf);
  86         if (err)
  87                 return (err);
  88         dd = dmu_buf_get_user(dbuf);
  89 #ifdef ZFS_DEBUG
  90         {
  91                 dmu_object_info_t doi;
  92                 dmu_object_info_from_db(dbuf, &doi);
  93                 ASSERT3U(doi.doi_type, ==, DMU_OT_DSL_DIR);
  94                 ASSERT3U(doi.doi_bonus_size, >=, sizeof (dsl_dir_phys_t));
  95         }
  96 #endif
  97         if (dd == NULL) {
  98                 dsl_dir_t *winner;
  99
 100                 dd = kmem_zalloc(sizeof (dsl_dir_t), KM_SLEEP);
 101                 dd->dd_object = ddobj;
 102                 dd->dd_dbuf = dbuf;
 103                 dd->dd_pool = dp;
 104                 dd->dd_phys = dbuf->db_data;
 105                 mutex_init(&dd->dd_lock, NULL, MUTEX_DEFAULT, NULL);
 106
 107                 list_create(&dd->dd_prop_cbs, sizeof (dsl_prop_cb_record_t),
 108                     offsetof(dsl_prop_cb_record_t, cbr_node));
 109
 110                 if (dd->dd_phys->dd_parent_obj) {
 111                         err = dsl_dir_open_obj(dp, dd->dd_phys->dd_parent_obj,
 112                             NULL, dd, &dd->dd_parent);
 113                         if (err)
 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)
 131                                 goto errout;
 132                 } else {
 133                         (void) strcpy(dd->dd_myname, spa_name(dp->dp_spa));
 134                 }
 135
 136                 winner = dmu_buf_set_user_ie(dbuf, dd, &dd->dd_phys,
 137                     dsl_dir_evict);
 138                 if (winner) {
 139                         if (dd->dd_parent)
 140                                 dsl_dir_close(dd->dd_parent, dd);
 141                         mutex_destroy(&dd->dd_lock);
 142                         kmem_free(dd, sizeof (dsl_dir_t));
 143                         dd = winner;
 144                 } else {
 145                         spa_open_ref(dp->dp_spa, dd);
 146                 }
 147         }
 148
 149         /*
 150          * The dsl_dir_t has both open-to-close and instantiate-to-evict
 151          * holds on the spa.  We need the open-to-close holds because
 152          * otherwise the spa_refcnt wouldn't change when we open a
 153          * dir which the spa also has open, so we could incorrectly
 154          * think it was OK to unload/export/destroy the pool.  We need
 155          * the instantiate-to-evict hold because the dsl_dir_t has a
 156          * pointer to the dd_pool, which has a pointer to the spa_t.
 157          */
 158         spa_open_ref(dp->dp_spa, tag);
 159         ASSERT3P(dd->dd_pool, ==, dp);
 160         ASSERT3U(dd->dd_object, ==, ddobj);
 161         ASSERT3P(dd->dd_dbuf, ==, dbuf);
 162         *ddp = dd;
 163         return (0);
 164
 165 errout:
 166         if (dd->dd_parent)
 167                 dsl_dir_close(dd->dd_parent, dd);
 168         mutex_destroy(&dd->dd_lock);
 169         kmem_free(dd, sizeof (dsl_dir_t));
 170         dmu_buf_rele(dbuf, tag);
 171         return (err);
 172
 173 }
 174
 175 void
 176 dsl_dir_close(dsl_dir_t *dd, void *tag)
 177 {
 178         dprintf_dd(dd, "%s\n", "");
 179         spa_close(dd->dd_pool->dp_spa, tag);
 180         dmu_buf_rele(dd->dd_dbuf, tag);
 181 }
 182
 183 /* buf must be long enough (MAXNAMELEN + strlen(MOS_DIR_NAME) + 1 should do) */
 184 void
 185 dsl_dir_name(dsl_dir_t *dd, char *buf)
 186 {
 187         if (dd->dd_parent) {
 188                 dsl_dir_name(dd->dd_parent, buf);
 189                 (void) strcat(buf, "/");
 190         } else {
 191                 buf[0] = '\0';
 192         }
 193         if (!MUTEX_HELD(&dd->dd_lock)) {
 194                 /*
 195                  * recursive mutex so that we can use
 196                  * dprintf_dd() with dd_lock held
 197                  */
 198                 mutex_enter(&dd->dd_lock);
 199                 (void) strcat(buf, dd->dd_myname);
 200                 mutex_exit(&dd->dd_lock);
 201         } else {
 202                 (void) strcat(buf, dd->dd_myname);
 203         }
 204 }
 205
 206 /* Calculate name legnth, avoiding all the strcat calls of dsl_dir_name */
 207 int
 208 dsl_dir_namelen(dsl_dir_t *dd)
 209 {
 210         int result = 0;
 211
 212         if (dd->dd_parent) {
 213                 /* parent's name + 1 for the "/" */
 214                 result = dsl_dir_namelen(dd->dd_parent) + 1;
 215         }
 216
 217         if (!MUTEX_HELD(&dd->dd_lock)) {
 218                 /* see dsl_dir_name */
 219                 mutex_enter(&dd->dd_lock);
 220                 result += strlen(dd->dd_myname);
 221                 mutex_exit(&dd->dd_lock);
 222         } else {
 223                 result += strlen(dd->dd_myname);
 224         }
 225
 226         return (result);
 227 }
 228
 229 static int
 230 getcomponent(const char *path, char *component, const char **nextp)
 231 {
 232         char *p;
 233         if ((path == NULL) || (path[0] == '\0'))
 234                 return (ENOENT);
 235         /* This would be a good place to reserve some namespace... */
 236         p = strpbrk(path, "/@");
 237         if (p && (p[1] == '/' || p[1] == '@')) {
 238                 /* two separators in a row */
 239                 return (EINVAL);
 240         }
 241         if (p == NULL || p == path) {
 242                 /*
 243                  * if the first thing is an @ or /, it had better be an
 244                  * @ and it had better not have any more ats or slashes,
 245                  * and it had better have something after the @.
 246                  */
 247                 if (p != NULL &&
 248                     (p[0] != '@' || strpbrk(path+1, "/@") || p[1] == '\0'))
 249                         return (EINVAL);
 250                 if (strlen(path) >= MAXNAMELEN)
 251                         return (ENAMETOOLONG);
 252                 (void) strcpy(component, path);
 253                 p = NULL;
 254         } else if (p[0] == '/') {
 255                 if (p-path >= MAXNAMELEN)
 256                         return (ENAMETOOLONG);
 257                 (void) strncpy(component, path, p - path);
 258                 component[p-path] = '\0';
 259                 p++;
 260         } else if (p[0] == '@') {
 261                 /*
 262                  * if the next separator is an @, there better not be
 263                  * any more slashes.
 264                  */
 265                 if (strchr(path, '/'))
 266                         return (EINVAL);
 267                 if (p-path >= MAXNAMELEN)
 268                         return (ENAMETOOLONG);
 269                 (void) strncpy(component, path, p - path);
 270                 component[p-path] = '\0';
 271         } else {
 272                 ASSERT(!"invalid p");
 273         }
 274         *nextp = p;
 275         return (0);
 276 }
 277
 278 /*
 279  * same as dsl_open_dir, ignore the first component of name and use the
 280  * spa instead
 281  */
 282 int
 283 dsl_dir_open_spa(spa_t *spa, const char *name, void *tag,
 284     dsl_dir_t **ddp, const char **tailp)
 285 {
 286         char buf[MAXNAMELEN];
 287         const char *next, *nextnext = NULL;
 288         int err;
 289         dsl_dir_t *dd;
 290         dsl_pool_t *dp;
 291         uint64_t ddobj;
 292         int openedspa = FALSE;
 293
 294         dprintf("%s\n", name);
 295
 296         err = getcomponent(name, buf, &next);
 297         if (err)
 298                 return (err);
 299         if (spa == NULL) {
 300                 err = spa_open(buf, &spa, FTAG);
 301                 if (err) {
 302                         dprintf("spa_open(%s) failed\n", buf);
 303                         return (err);
 304                 }
 305                 openedspa = TRUE;
 306
 307                 /* XXX this assertion belongs in spa_open */
 308                 ASSERT(!dsl_pool_sync_context(spa_get_dsl(spa)));
 309         }
 310
 311         dp = spa_get_dsl(spa);
 312
 313         rw_enter(&dp->dp_config_rwlock, RW_READER);
 314         err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj, NULL, tag, &dd);
 315         if (err) {
 316                 rw_exit(&dp->dp_config_rwlock);
 317                 if (openedspa)
 318                         spa_close(spa, FTAG);
 319                 return (err);
 320         }
 321
 322         while (next != NULL) {
 323                 dsl_dir_t *child_ds;
 324                 err = getcomponent(next, buf, &nextnext);
 325                 if (err)
 326                         break;
 327                 ASSERT(next[0] != '\0');
 328                 if (next[0] == '@')
 329                         break;
 330                 dprintf("looking up %s in obj%lld\n",
 331                     buf, dd->dd_phys->dd_child_dir_zapobj);
 332
 333                 err = zap_lookup(dp->dp_meta_objset,
 334                     dd->dd_phys->dd_child_dir_zapobj,
 335                     buf, sizeof (ddobj), 1, &ddobj);
 336                 if (err) {
 337                         if (err == ENOENT)
 338                                 err = 0;
 339                         break;
 340                 }
 341
 342                 err = dsl_dir_open_obj(dp, ddobj, buf, tag, &child_ds);
 343                 if (err)
 344                         break;
 345                 dsl_dir_close(dd, tag);
 346                 dd = child_ds;
 347                 next = nextnext;
 348         }
 349         rw_exit(&dp->dp_config_rwlock);
 350
 351         if (err) {
 352                 dsl_dir_close(dd, tag);
 353                 if (openedspa)
 354                         spa_close(spa, FTAG);
 355                 return (err);
 356         }
 357
 358         /*
 359          * It's an error if there's more than one component left, or
 360          * tailp==NULL and there's any component left.
 361          */
 362         if (next != NULL &&
 363             (tailp == NULL || (nextnext && nextnext[0] != '\0'))) {
 364                 /* bad path name */
 365                 dsl_dir_close(dd, tag);
 366                 dprintf("next=%p (%s) tail=%p\n", next, next?next:"", tailp);
 367                 err = ENOENT;
 368         }
 369         if (tailp)
 370                 *tailp = next;
 371         if (openedspa)
 372                 spa_close(spa, FTAG);
 373         *ddp = dd;
 374         return (err);
 375 }
 376
 377 /*
 378  * Return the dsl_dir_t, and possibly the last component which couldn't
 379  * be found in *tail.  Return NULL if the path is bogus, or if
 380  * tail==NULL and we couldn't parse the whole name.  (*tail)[0] == '@'
 381  * means that the last component is a snapshot.
 382  */
 383 int
 384 dsl_dir_open(const char *name, void *tag, dsl_dir_t **ddp, const char **tailp)
 385 {
 386         return (dsl_dir_open_spa(NULL, name, tag, ddp, tailp));
 387 }
 388
 389 uint64_t
 390 dsl_dir_create_sync(dsl_pool_t *dp, dsl_dir_t *pds, const char *name,
 391     dmu_tx_t *tx)
 392 {
 393         objset_t *mos = dp->dp_meta_objset;
 394         uint64_t ddobj;
 395         dsl_dir_phys_t *dsphys;
 396         dmu_buf_t *dbuf;
 397
 398         ddobj = dmu_object_alloc(mos, DMU_OT_DSL_DIR, 0,
 399             DMU_OT_DSL_DIR, sizeof (dsl_dir_phys_t), tx);
 400         if (pds) {
 401                 VERIFY(0 == zap_add(mos, pds->dd_phys->dd_child_dir_zapobj,
 402                     name, sizeof (uint64_t), 1, &ddobj, tx));
 403         } else {
 404                 /* it's the root dir */
 405                 VERIFY(0 == zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
 406                     DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, &ddobj, tx));
 407         }
 408         VERIFY(0 == dmu_bonus_hold(mos, ddobj, FTAG, &dbuf));
 409         dmu_buf_will_dirty(dbuf, tx);
 410         dsphys = dbuf->db_data;
 411
 412         dsphys->dd_creation_time = gethrestime_sec();
 413         if (pds)
 414                 dsphys->dd_parent_obj = pds->dd_object;
 415         dsphys->dd_props_zapobj = zap_create(mos,
 416             DMU_OT_DSL_PROPS, DMU_OT_NONE, 0, tx);
 417         dsphys->dd_child_dir_zapobj = zap_create(mos,
 418             DMU_OT_DSL_DIR_CHILD_MAP, DMU_OT_NONE, 0, tx);
 419         if (spa_version(dp->dp_spa) >= SPA_VERSION_USED_BREAKDOWN)
 420                 dsphys->dd_flags |= DD_FLAG_USED_BREAKDOWN;
 421         dmu_buf_rele(dbuf, FTAG);
 422
 423         return (ddobj);
 424 }
 425
 426 /* ARGSUSED */
 427 int
 428 dsl_dir_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx)
 429 {
 430         dsl_dir_t *dd = arg1;
 431         dsl_pool_t *dp = dd->dd_pool;
 432         objset_t *mos = dp->dp_meta_objset;
 433         int err;
 434         uint64_t count;
 435
 436         /*
 437          * There should be exactly two holds, both from
 438          * dsl_dataset_destroy: one on the dd directory, and one on its
 439          * head ds.  Otherwise, someone is trying to lookup something
 440          * inside this dir while we want to destroy it.  The
 441          * config_rwlock ensures that nobody else opens it after we
 442          * check.
 443          */
 444         if (dmu_buf_refcount(dd->dd_dbuf) > 2)
 445                 return (EBUSY);
 446
 447         err = zap_count(mos, dd->dd_phys->dd_child_dir_zapobj, &count);
 448         if (err)
 449                 return (err);
 450         if (count != 0)
 451                 return (EEXIST);
 452
 453         return (0);
 454 }
 455
 456 void
 457 dsl_dir_destroy_sync(void *arg1, void *tag, cred_t *cr, dmu_tx_t *tx)
 458 {
 459         dsl_dir_t *dd = arg1;
 460         objset_t *mos = dd->dd_pool->dp_meta_objset;
 461         uint64_t val, obj;
 462         dd_used_t t;
 463
 464         ASSERT(RW_WRITE_HELD(&dd->dd_pool->dp_config_rwlock));
 465         ASSERT(dd->dd_phys->dd_head_dataset_obj == 0);
 466
 467         /* Remove our reservation. */
 468         val = 0;
 469         dsl_dir_set_reservation_sync(dd, &val, cr, tx);
 470         ASSERT3U(dd->dd_phys->dd_used_bytes, ==, 0);
 471         ASSERT3U(dd->dd_phys->dd_reserved, ==, 0);
 472         for (t = 0; t < DD_USED_NUM; t++)
 473                 ASSERT3U(dd->dd_phys->dd_used_breakdown[t], ==, 0);
 474
 475         VERIFY(0 == zap_destroy(mos, dd->dd_phys->dd_child_dir_zapobj, tx));
 476         VERIFY(0 == zap_destroy(mos, dd->dd_phys->dd_props_zapobj, tx));
 477         VERIFY(0 == dsl_deleg_destroy(mos, dd->dd_phys->dd_deleg_zapobj, tx));
 478         VERIFY(0 == zap_remove(mos,
 479             dd->dd_parent->dd_phys->dd_child_dir_zapobj, dd->dd_myname, tx));
 480
 481         obj = dd->dd_object;
 482         dsl_dir_close(dd, tag);
 483         VERIFY(0 == dmu_object_free(mos, obj, tx));
 484 }
 485
 486 boolean_t
 487 dsl_dir_is_clone(dsl_dir_t *dd)
 488 {
 489         return (dd->dd_phys->dd_origin_obj &&
 490             (dd->dd_pool->dp_origin_snap == NULL ||
 491             dd->dd_phys->dd_origin_obj !=
 492             dd->dd_pool->dp_origin_snap->ds_object));
 493 }
 494
 495 void
 496 dsl_dir_stats(dsl_dir_t *dd, nvlist_t *nv)
 497 {
 498         mutex_enter(&dd->dd_lock);
 499         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
 500             dd->dd_phys->dd_used_bytes);
 501         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_QUOTA, dd->dd_phys->dd_quota);
 502         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_RESERVATION,
 503             dd->dd_phys->dd_reserved);
 504         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
 505             dd->dd_phys->dd_compressed_bytes == 0 ? 100 :
 506             (dd->dd_phys->dd_uncompressed_bytes * 100 /
 507             dd->dd_phys->dd_compressed_bytes));
 508         if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
 509                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDSNAP,
 510                     dd->dd_phys->dd_used_breakdown[DD_USED_SNAP]);
 511                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDDS,
 512                     dd->dd_phys->dd_used_breakdown[DD_USED_HEAD]);
 513                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDREFRESERV,
 514                     dd->dd_phys->dd_used_breakdown[DD_USED_REFRSRV]);
 515                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDCHILD,
 516                     dd->dd_phys->dd_used_breakdown[DD_USED_CHILD] +
 517                     dd->dd_phys->dd_used_breakdown[DD_USED_CHILD_RSRV]);
 518         }
 519         mutex_exit(&dd->dd_lock);
 520
 521         rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
 522         if (dsl_dir_is_clone(dd)) {
 523                 dsl_dataset_t *ds;
 524                 char buf[MAXNAMELEN];
 525
 526                 VERIFY(0 == dsl_dataset_hold_obj(dd->dd_pool,
 527                     dd->dd_phys->dd_origin_obj, FTAG, &ds));
 528                 dsl_dataset_name(ds, buf);
 529                 dsl_dataset_rele(ds, FTAG);
 530                 dsl_prop_nvlist_add_string(nv, ZFS_PROP_ORIGIN, buf);
 531         }
 532         rw_exit(&dd->dd_pool->dp_config_rwlock);
 533 }
 534
 535 void
 536 dsl_dir_dirty(dsl_dir_t *dd, dmu_tx_t *tx)
 537 {
 538         dsl_pool_t *dp = dd->dd_pool;
 539
 540         ASSERT(dd->dd_phys);
 541
 542         if (txg_list_add(&dp->dp_dirty_dirs, dd, tx->tx_txg) == 0) {
 543                 /* up the hold count until we can be written out */
 544                 dmu_buf_add_ref(dd->dd_dbuf, dd);
 545         }
 546 }
 547
 548 static int64_t
 549 parent_delta(dsl_dir_t *dd, uint64_t used, int64_t delta)
 550 {
 551         uint64_t old_accounted = MAX(used, dd->dd_phys->dd_reserved);
 552         uint64_t new_accounted = MAX(used + delta, dd->dd_phys->dd_reserved);
 553         return (new_accounted - old_accounted);
 554 }
 555
 556 void
 557 dsl_dir_sync(dsl_dir_t *dd, dmu_tx_t *tx)
 558 {
 559         ASSERT(dmu_tx_is_syncing(tx));
 560
 561         dmu_buf_will_dirty(dd->dd_dbuf, tx);
 562
 563         mutex_enter(&dd->dd_lock);
 564         ASSERT3U(dd->dd_tempreserved[tx->tx_txg&TXG_MASK], ==, 0);
 565         dprintf_dd(dd, "txg=%llu towrite=%lluK\n", tx->tx_txg,
 566             dd->dd_space_towrite[tx->tx_txg&TXG_MASK] / 1024);
 567         dd->dd_space_towrite[tx->tx_txg&TXG_MASK] = 0;
 568         mutex_exit(&dd->dd_lock);
 569
 570         /* release the hold from dsl_dir_dirty */
 571         dmu_buf_rele(dd->dd_dbuf, dd);
 572 }
 573
 574 static uint64_t
 575 dsl_dir_space_towrite(dsl_dir_t *dd)
 576 {
 577         uint64_t space = 0;
 578         int i;
 579
 580         ASSERT(MUTEX_HELD(&dd->dd_lock));
 581
 582         for (i = 0; i < TXG_SIZE; i++) {
 583                 space += dd->dd_space_towrite[i&TXG_MASK];
 584                 ASSERT3U(dd->dd_space_towrite[i&TXG_MASK], >=, 0);
 585         }
 586         return (space);
 587 }
 588
 589 /*
 590  * How much space would dd have available if ancestor had delta applied
 591  * to it?  If ondiskonly is set, we're only interested in what's
 592  * on-disk, not estimated pending changes.
 593  */
 594 uint64_t
 595 dsl_dir_space_available(dsl_dir_t *dd,
 596     dsl_dir_t *ancestor, int64_t delta, int ondiskonly)
 597 {
 598         uint64_t parentspace, myspace, quota, used;
 599
 600         /*
 601          * If there are no restrictions otherwise, assume we have
 602          * unlimited space available.
 603          */
 604         quota = UINT64_MAX;
 605         parentspace = UINT64_MAX;
 606
 607         if (dd->dd_parent != NULL) {
 608                 parentspace = dsl_dir_space_available(dd->dd_parent,
 609                     ancestor, delta, ondiskonly);
 610         }
 611
 612         mutex_enter(&dd->dd_lock);
 613         if (dd->dd_phys->dd_quota != 0)
 614                 quota = dd->dd_phys->dd_quota;
 615         used = dd->dd_phys->dd_used_bytes;
 616         if (!ondiskonly)
 617                 used += dsl_dir_space_towrite(dd);
 618
 619         if (dd->dd_parent == NULL) {
 620                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, FALSE);
 621                 quota = MIN(quota, poolsize);
 622         }
 623
 624         if (dd->dd_phys->dd_reserved > used && parentspace != UINT64_MAX) {
 625                 /*
 626                  * We have some space reserved, in addition to what our
 627                  * parent gave us.
 628                  */
 629                 parentspace += dd->dd_phys->dd_reserved - used;
 630         }
 631
 632         if (dd == ancestor) {
 633                 ASSERT(delta <= 0);
 634                 ASSERT(used >= -delta);
 635                 used += delta;
 636                 if (parentspace != UINT64_MAX)
 637                         parentspace -= delta;
 638         }
 639
 640         if (used > quota) {
 641                 /* over quota */
 642                 myspace = 0;
 643
 644                 /*
 645                  * While it's OK to be a little over quota, if
 646                  * we think we are using more space than there
 647                  * is in the pool (which is already 1.6% more than
 648                  * dsl_pool_adjustedsize()), something is very
 649                  * wrong.
 650                  */
 651                 ASSERT3U(used, <=, spa_get_space(dd->dd_pool->dp_spa));
 652         } else {
 653                 /*
 654                  * the lesser of the space provided by our parent and
 655                  * the space left in our quota
 656                  */
 657                 myspace = MIN(parentspace, quota - used);
 658         }
 659
 660         mutex_exit(&dd->dd_lock);
 661
 662         return (myspace);
 663 }
 664
 665 struct tempreserve {
 666         list_node_t tr_node;
 667         dsl_pool_t *tr_dp;
 668         dsl_dir_t *tr_ds;
 669         uint64_t tr_size;
 670 };
 671
 672 static int
 673 dsl_dir_tempreserve_impl(dsl_dir_t *dd, uint64_t asize, boolean_t netfree,
 674     boolean_t ignorequota, boolean_t checkrefquota, list_t *tr_list,
 675     dmu_tx_t *tx, boolean_t first)
 676 {
 677         uint64_t txg = tx->tx_txg;
 678         uint64_t est_inflight, used_on_disk, quota, parent_rsrv;
 679         struct tempreserve *tr;
 680         int enospc = EDQUOT;
 681         int txgidx = txg & TXG_MASK;
 682         int i;
 683         uint64_t ref_rsrv = 0;
 684
 685         ASSERT3U(txg, !=, 0);
 686         ASSERT3S(asize, >, 0);
 687
 688         mutex_enter(&dd->dd_lock);
 689
 690         /*
 691          * Check against the dsl_dir's quota.  We don't add in the delta
 692          * when checking for over-quota because they get one free hit.
 693          */
 694         est_inflight = dsl_dir_space_towrite(dd);
 695         for (i = 0; i < TXG_SIZE; i++)
 696                 est_inflight += dd->dd_tempreserved[i];
 697         used_on_disk = dd->dd_phys->dd_used_bytes;
 698
 699         /*
 700          * On the first iteration, fetch the dataset's used-on-disk and
 701          * refreservation values. Also, if checkrefquota is set, test if
 702          * allocating this space would exceed the dataset's refquota.
 703          */
 704         if (first && tx->tx_objset) {
 705                 int error;
 706                 dsl_dataset_t *ds = tx->tx_objset->os->os_dsl_dataset;
 707
 708                 error = dsl_dataset_check_quota(ds, checkrefquota,
 709                     asize, est_inflight, &used_on_disk, &ref_rsrv);
 710                 if (error) {
 711                         mutex_exit(&dd->dd_lock);
 712                         return (error);
 713                 }
 714         }
 715
 716         /*
 717          * If this transaction will result in a net free of space,
 718          * we want to let it through.
 719          */
 720         if (ignorequota || netfree || dd->dd_phys->dd_quota == 0)
 721                 quota = UINT64_MAX;
 722         else
 723                 quota = dd->dd_phys->dd_quota;
 724
 725         /*
 726          * Adjust the quota against the actual pool size at the root.
 727          * To ensure that it's possible to remove files from a full
 728          * pool without inducing transient overcommits, we throttle
 729          * netfree transactions against a quota that is slightly larger,
 730          * but still within the pool's allocation slop.  In cases where
 731          * we're very close to full, this will allow a steady trickle of
 732          * removes to get through.
 733          */
 734         if (dd->dd_parent == NULL) {
 735                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, netfree);
 736                 if (poolsize < quota) {
 737                         quota = poolsize;
 738                         enospc = ENOSPC;
 739                 }
 740         }
 741
 742         /*
 743          * If they are requesting more space, and our current estimate
 744          * is over quota, they get to try again unless the actual
 745          * on-disk is over quota and there are no pending changes (which
 746          * may free up space for us).
 747          */
 748         if (used_on_disk + est_inflight > quota) {
 749                 if (est_inflight > 0 || used_on_disk < quota)
 750                         enospc = ERESTART;
 751                 dprintf_dd(dd, "failing: used=%lluK inflight = %lluK "
 752                     "quota=%lluK tr=%lluK err=%d\n",
 753                     used_on_disk>>10, est_inflight>>10,
 754                     quota>>10, asize>>10, enospc);
 755                 mutex_exit(&dd->dd_lock);
 756                 return (enospc);
 757         }
 758
 759         /* We need to up our estimated delta before dropping dd_lock */
 760         dd->dd_tempreserved[txgidx] += asize;
 761
 762         parent_rsrv = parent_delta(dd, used_on_disk + est_inflight,
 763             asize - ref_rsrv);
 764         mutex_exit(&dd->dd_lock);
 765
 766         tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 767         tr->tr_ds = dd;
 768         tr->tr_size = asize;
 769         list_insert_tail(tr_list, tr);
 770
 771         /* see if it's OK with our parent */
 772         if (dd->dd_parent && parent_rsrv) {
 773                 boolean_t ismos = (dd->dd_phys->dd_head_dataset_obj == 0);
 774
 775                 return (dsl_dir_tempreserve_impl(dd->dd_parent,
 776                     parent_rsrv, netfree, ismos, TRUE, tr_list, tx, FALSE));
 777         } else {
 778                 return (0);
 779         }
 780 }
 781
 782 /*
 783  * Reserve space in this dsl_dir, to be used in this tx's txg.
 784  * After the space has been dirtied (and dsl_dir_willuse_space()
 785  * has been called), the reservation should be canceled, using
 786  * dsl_dir_tempreserve_clear().
 787  */
 788 int
 789 dsl_dir_tempreserve_space(dsl_dir_t *dd, uint64_t lsize, uint64_t asize,
 790     uint64_t fsize, uint64_t usize, void **tr_cookiep, dmu_tx_t *tx)
 791 {
 792         int err;
 793         list_t *tr_list;
 794
 795         if (asize == 0) {
 796                 *tr_cookiep = NULL;
 797                 return (0);
 798         }
 799
 800         tr_list = kmem_alloc(sizeof (list_t), KM_SLEEP);
 801         list_create(tr_list, sizeof (struct tempreserve),
 802             offsetof(struct tempreserve, tr_node));
 803         ASSERT3S(asize, >, 0);
 804         ASSERT3S(fsize, >=, 0);
 805
 806         err = arc_tempreserve_space(lsize, tx->tx_txg);
 807         if (err == 0) {
 808                 struct tempreserve *tr;
 809
 810                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 811                 tr->tr_size = lsize;
 812                 list_insert_tail(tr_list, tr);
 813
 814                 err = dsl_pool_tempreserve_space(dd->dd_pool, asize, tx);
 815         } else {
 816                 if (err == EAGAIN) {
 817                         txg_delay(dd->dd_pool, tx->tx_txg, 1);
 818                         err = ERESTART;
 819                 }
 820                 dsl_pool_memory_pressure(dd->dd_pool);
 821         }
 822
 823         if (err == 0) {
 824                 struct tempreserve *tr;
 825
 826                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
 827                 tr->tr_dp = dd->dd_pool;
 828                 tr->tr_size = asize;
 829                 list_insert_tail(tr_list, tr);
 830
 831                 err = dsl_dir_tempreserve_impl(dd, asize, fsize >= asize,
 832                     FALSE, asize > usize, tr_list, tx, TRUE);
 833         }
 834
 835         if (err)
 836                 dsl_dir_tempreserve_clear(tr_list, tx);
 837         else
 838                 *tr_cookiep = tr_list;
 839
 840         return (err);
 841 }
 842
 843 /*
 844  * Clear a temporary reservation that we previously made with
 845  * dsl_dir_tempreserve_space().
 846  */
 847 void
 848 dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
 849 {
 850         int txgidx = tx->tx_txg & TXG_MASK;
 851         list_t *tr_list = tr_cookie;
 852         struct tempreserve *tr;
 853
 854         ASSERT3U(tx->tx_txg, !=, 0);
 855
 856         if (tr_cookie == NULL)
 857                 return;
 858
 859         while (tr = list_head(tr_list)) {
 860                 if (tr->tr_dp) {
 861                         dsl_pool_tempreserve_clear(tr->tr_dp, tr->tr_size, tx);
 862                 } else if (tr->tr_ds) {
 863                         mutex_enter(&tr->tr_ds->dd_lock);
 864                         ASSERT3U(tr->tr_ds->dd_tempreserved[txgidx], >=,
 865                             tr->tr_size);
 866                         tr->tr_ds->dd_tempreserved[txgidx] -= tr->tr_size;
 867                         mutex_exit(&tr->tr_ds->dd_lock);
 868                 } else {
 869                         arc_tempreserve_clear(tr->tr_size);
 870                 }
 871                 list_remove(tr_list, tr);
 872                 kmem_free(tr, sizeof (struct tempreserve));
 873         }
 874
 875         kmem_free(tr_list, sizeof (list_t));
 876 }
 877
 878 static void
 879 dsl_dir_willuse_space_impl(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
 880 {
 881         int64_t parent_space;
 882         uint64_t est_used;
 883
 884         mutex_enter(&dd->dd_lock);
 885         if (space > 0)
 886                 dd->dd_space_towrite[tx->tx_txg & TXG_MASK] += space;
 887
 888         est_used = dsl_dir_space_towrite(dd) + dd->dd_phys->dd_used_bytes;
 889         parent_space = parent_delta(dd, est_used, space);
 890         mutex_exit(&dd->dd_lock);
 891
 892         /* Make sure that we clean up dd_space_to* */
 893         dsl_dir_dirty(dd, tx);
 894
 895         /* XXX this is potentially expensive and unnecessary... */
 896         if (parent_space && dd->dd_parent)
 897                 dsl_dir_willuse_space_impl(dd->dd_parent, parent_space, tx);
 898 }
 899
 900 /*
 901  * Call in open context when we think we're going to write/free space,
 902  * eg. when dirtying data.  Be conservative (ie. OK to write less than
 903  * this or free more than this, but don't write more or free less).
 904  */
 905 void
 906 dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
 907 {
 908         dsl_pool_willuse_space(dd->dd_pool, space, tx);
 909         dsl_dir_willuse_space_impl(dd, space, tx);
 910 }
 911
 912 /* call from syncing context when we actually write/free space for this dd */
 913 void
 914 dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
 915     int64_t used, int64_t compressed, int64_t uncompressed, dmu_tx_t *tx)
 916 {
 917         int64_t accounted_delta;
 918         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
 919
 920         ASSERT(dmu_tx_is_syncing(tx));
 921         ASSERT(type < DD_USED_NUM);
 922
 923         dsl_dir_dirty(dd, tx);
 924
 925         if (needlock)
 926                 mutex_enter(&dd->dd_lock);
 927         accounted_delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, used);
 928         ASSERT(used >= 0 || dd->dd_phys->dd_used_bytes >= -used);
 929         ASSERT(compressed >= 0 ||
 930             dd->dd_phys->dd_compressed_bytes >= -compressed);
 931         ASSERT(uncompressed >= 0 ||
 932             dd->dd_phys->dd_uncompressed_bytes >= -uncompressed);
 933         dd->dd_phys->dd_used_bytes += used;
 934         dd->dd_phys->dd_uncompressed_bytes += uncompressed;
 935         dd->dd_phys->dd_compressed_bytes += compressed;
 936
 937         if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
 938                 ASSERT(used > 0 ||
 939                     dd->dd_phys->dd_used_breakdown[type] >= -used);
 940                 dd->dd_phys->dd_used_breakdown[type] += used;
 941 #ifdef DEBUG
 942                 dd_used_t t;
 943                 uint64_t u = 0;
 944                 for (t = 0; t < DD_USED_NUM; t++)
 945                         u += dd->dd_phys->dd_used_breakdown[t];
 946                 ASSERT3U(u, ==, dd->dd_phys->dd_used_bytes);
 947 #endif
 948         }
 949         if (needlock)
 950                 mutex_exit(&dd->dd_lock);
 951
 952         if (dd->dd_parent != NULL) {
 953                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
 954                     accounted_delta, compressed, uncompressed, tx);
 955                 dsl_dir_transfer_space(dd->dd_parent,
 956                     used - accounted_delta,
 957                     DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
 958         }
 959 }
 960
 961 void
 962 dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
 963     dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
 964 {
 965         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
 966
 967         ASSERT(dmu_tx_is_syncing(tx));
 968         ASSERT(oldtype < DD_USED_NUM);
 969         ASSERT(newtype < DD_USED_NUM);
 970
 971         if (delta == 0 || !(dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN))
 972                 return;
 973
 974         dsl_dir_dirty(dd, tx);
 975         if (needlock)
 976                 mutex_enter(&dd->dd_lock);
 977         ASSERT(delta > 0 ?
 978             dd->dd_phys->dd_used_breakdown[oldtype] >= delta :
 979             dd->dd_phys->dd_used_breakdown[newtype] >= -delta);
 980         ASSERT(dd->dd_phys->dd_used_bytes >= ABS(delta));
 981         dd->dd_phys->dd_used_breakdown[oldtype] -= delta;
 982         dd->dd_phys->dd_used_breakdown[newtype] += delta;
 983         if (needlock)
 984                 mutex_exit(&dd->dd_lock);
 985 }
 986
 987 static int
 988 dsl_dir_set_quota_check(void *arg1, void *arg2, dmu_tx_t *tx)
 989 {
 990         dsl_dir_t *dd = arg1;
 991         uint64_t *quotap = arg2;
 992         uint64_t new_quota = *quotap;
 993         int err = 0;
 994         uint64_t towrite;
 995
 996         if (new_quota == 0)
 997                 return (0);
 998
 999         mutex_enter(&dd->dd_lock);
1000         /*
1001          * If we are doing the preliminary check in open context, and
1002          * there are pending changes, then don't fail it, since the
1003          * pending changes could under-estimate the amount of space to be
1004          * freed up.
1005          */
1006         towrite = dsl_dir_space_towrite(dd);
1007         if ((dmu_tx_is_syncing(tx) || towrite == 0) &&
1008             (new_quota < dd->dd_phys->dd_reserved ||
1009             new_quota < dd->dd_phys->dd_used_bytes + towrite)) {
1010                 err = ENOSPC;
1011         }
1012         mutex_exit(&dd->dd_lock);
1013         return (err);
1014 }
1015
1016 /* ARGSUSED */
1017 static void
1018 dsl_dir_set_quota_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1019 {
1020         dsl_dir_t *dd = arg1;
1021         uint64_t *quotap = arg2;
1022         uint64_t new_quota = *quotap;
1023
1024         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1025
1026         mutex_enter(&dd->dd_lock);
1027         dd->dd_phys->dd_quota = new_quota;
1028         mutex_exit(&dd->dd_lock);
1029
1030         spa_history_internal_log(LOG_DS_QUOTA, dd->dd_pool->dp_spa,
1031             tx, cr, "%lld dataset = %llu ",
1032             (longlong_t)new_quota, dd->dd_phys->dd_head_dataset_obj);
1033 }
1034
1035 int
1036 dsl_dir_set_quota(const char *ddname, uint64_t quota)
1037 {
1038         dsl_dir_t *dd;
1039         int err;
1040
1041         err = dsl_dir_open(ddname, FTAG, &dd, NULL);
1042         if (err)
1043                 return (err);
1044
1045         if (quota != dd->dd_phys->dd_quota) {
1046                 /*
1047                  * If someone removes a file, then tries to set the quota, we
1048                  * want to make sure the file freeing takes effect.
1049                  */
1050                 txg_wait_open(dd->dd_pool, 0);
1051
1052                 err = dsl_sync_task_do(dd->dd_pool, dsl_dir_set_quota_check,
1053                     dsl_dir_set_quota_sync, dd, &quota, 0);
1054         }
1055         dsl_dir_close(dd, FTAG);
1056         return (err);
1057 }
1058
1059 int
1060 dsl_dir_set_reservation_check(void *arg1, void *arg2, dmu_tx_t *tx)
1061 {
1062         dsl_dir_t *dd = arg1;
1063         uint64_t *reservationp = arg2;
1064         uint64_t new_reservation = *reservationp;
1065         uint64_t used, avail;
1066
1067         /*
1068          * If we are doing the preliminary check in open context, the
1069          * space estimates may be inaccurate.
1070          */
1071         if (!dmu_tx_is_syncing(tx))
1072                 return (0);
1073
1074         mutex_enter(&dd->dd_lock);
1075         used = dd->dd_phys->dd_used_bytes;
1076         mutex_exit(&dd->dd_lock);
1077
1078         if (dd->dd_parent) {
1079                 avail = dsl_dir_space_available(dd->dd_parent,
1080                     NULL, 0, FALSE);
1081         } else {
1082                 avail = dsl_pool_adjustedsize(dd->dd_pool, B_FALSE) - used;
1083         }
1084
1085         if (MAX(used, new_reservation) > MAX(used, dd->dd_phys->dd_reserved)) {
1086                 uint64_t delta = MAX(used, new_reservation) -
1087                     MAX(used, dd->dd_phys->dd_reserved);
1088
1089                 if (delta > avail)
1090                         return (ENOSPC);
1091                 if (dd->dd_phys->dd_quota > 0 &&
1092                     new_reservation > dd->dd_phys->dd_quota)
1093                         return (ENOSPC);
1094         }
1095
1096         return (0);
1097 }
1098
1099 /* ARGSUSED */
1100 static void
1101 dsl_dir_set_reservation_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1102 {
1103         dsl_dir_t *dd = arg1;
1104         uint64_t *reservationp = arg2;
1105         uint64_t new_reservation = *reservationp;
1106         uint64_t used;
1107         int64_t delta;
1108
1109         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1110
1111         mutex_enter(&dd->dd_lock);
1112         used = dd->dd_phys->dd_used_bytes;
1113         delta = MAX(used, new_reservation) -
1114             MAX(used, dd->dd_phys->dd_reserved);
1115         dd->dd_phys->dd_reserved = new_reservation;
1116
1117         if (dd->dd_parent != NULL) {
1118                 /* Roll up this additional usage into our ancestors */
1119                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1120                     delta, 0, 0, tx);
1121         }
1122         mutex_exit(&dd->dd_lock);
1123
1124         spa_history_internal_log(LOG_DS_RESERVATION, dd->dd_pool->dp_spa,
1125             tx, cr, "%lld dataset = %llu",
1126             (longlong_t)new_reservation, dd->dd_phys->dd_head_dataset_obj);
1127 }
1128
1129 int
1130 dsl_dir_set_reservation(const char *ddname, uint64_t reservation)
1131 {
1132         dsl_dir_t *dd;
1133         int err;
1134
1135         err = dsl_dir_open(ddname, FTAG, &dd, NULL);
1136         if (err)
1137                 return (err);
1138         err = dsl_sync_task_do(dd->dd_pool, dsl_dir_set_reservation_check,
1139             dsl_dir_set_reservation_sync, dd, &reservation, 0);
1140         dsl_dir_close(dd, FTAG);
1141         return (err);
1142 }
1143
1144 static dsl_dir_t *
1145 closest_common_ancestor(dsl_dir_t *ds1, dsl_dir_t *ds2)
1146 {
1147         for (; ds1; ds1 = ds1->dd_parent) {
1148                 dsl_dir_t *dd;
1149                 for (dd = ds2; dd; dd = dd->dd_parent) {
1150                         if (ds1 == dd)
1151                                 return (dd);
1152                 }
1153         }
1154         return (NULL);
1155 }
1156
1157 /*
1158  * If delta is applied to dd, how much of that delta would be applied to
1159  * ancestor?  Syncing context only.
1160  */
1161 static int64_t
1162 would_change(dsl_dir_t *dd, int64_t delta, dsl_dir_t *ancestor)
1163 {
1164         if (dd == ancestor)
1165                 return (delta);
1166
1167         mutex_enter(&dd->dd_lock);
1168         delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, delta);
1169         mutex_exit(&dd->dd_lock);
1170         return (would_change(dd->dd_parent, delta, ancestor));
1171 }
1172
1173 struct renamearg {
1174         dsl_dir_t *newparent;
1175         const char *mynewname;
1176 };
1177
1178 /*ARGSUSED*/
1179 static int
1180 dsl_dir_rename_check(void *arg1, void *arg2, dmu_tx_t *tx)
1181 {
1182         dsl_dir_t *dd = arg1;
1183         struct renamearg *ra = arg2;
1184         dsl_pool_t *dp = dd->dd_pool;
1185         objset_t *mos = dp->dp_meta_objset;
1186         int err;
1187         uint64_t val;
1188
1189         /* There should be 2 references: the open and the dirty */
1190         if (dmu_buf_refcount(dd->dd_dbuf) > 2)
1191                 return (EBUSY);
1192
1193         /* check for existing name */
1194         err = zap_lookup(mos, ra->newparent->dd_phys->dd_child_dir_zapobj,
1195             ra->mynewname, 8, 1, &val);
1196         if (err == 0)
1197                 return (EEXIST);
1198         if (err != ENOENT)
1199                 return (err);
1200
1201         if (ra->newparent != dd->dd_parent) {
1202                 /* is there enough space? */
1203                 uint64_t myspace =
1204                     MAX(dd->dd_phys->dd_used_bytes, dd->dd_phys->dd_reserved);
1205
1206                 /* no rename into our descendant */
1207                 if (closest_common_ancestor(dd, ra->newparent) == dd)
1208                         return (EINVAL);
1209
1210                 if (err = dsl_dir_transfer_possible(dd->dd_parent,
1211                     ra->newparent, myspace))
1212                         return (err);
1213         }
1214
1215         return (0);
1216 }
1217
1218 static void
1219 dsl_dir_rename_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1220 {
1221         dsl_dir_t *dd = arg1;
1222         struct renamearg *ra = arg2;
1223         dsl_pool_t *dp = dd->dd_pool;
1224         objset_t *mos = dp->dp_meta_objset;
1225         int err;
1226
1227         ASSERT(dmu_buf_refcount(dd->dd_dbuf) <= 2);
1228
1229         if (ra->newparent != dd->dd_parent) {
1230                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
1231                     -dd->dd_phys->dd_used_bytes,
1232                     -dd->dd_phys->dd_compressed_bytes,
1233                     -dd->dd_phys->dd_uncompressed_bytes, tx);
1234                 dsl_dir_diduse_space(ra->newparent, DD_USED_CHILD,
1235                     dd->dd_phys->dd_used_bytes,
1236                     dd->dd_phys->dd_compressed_bytes,
1237                     dd->dd_phys->dd_uncompressed_bytes, tx);
1238
1239                 if (dd->dd_phys->dd_reserved > dd->dd_phys->dd_used_bytes) {
1240                         uint64_t unused_rsrv = dd->dd_phys->dd_reserved -
1241                             dd->dd_phys->dd_used_bytes;
1242
1243                         dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1244                             -unused_rsrv, 0, 0, tx);
1245                         dsl_dir_diduse_space(ra->newparent, DD_USED_CHILD_RSRV,
1246                             unused_rsrv, 0, 0, tx);
1247                 }
1248         }
1249
1250         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1251
1252         /* remove from old parent zapobj */
1253         err = zap_remove(mos, dd->dd_parent->dd_phys->dd_child_dir_zapobj,
1254             dd->dd_myname, tx);
1255         ASSERT3U(err, ==, 0);
1256
1257         (void) strcpy(dd->dd_myname, ra->mynewname);
1258         dsl_dir_close(dd->dd_parent, dd);
1259         dd->dd_phys->dd_parent_obj = ra->newparent->dd_object;
1260         VERIFY(0 == dsl_dir_open_obj(dd->dd_pool,
1261             ra->newparent->dd_object, NULL, dd, &dd->dd_parent));
1262
1263         /* add to new parent zapobj */
1264         err = zap_add(mos, ra->newparent->dd_phys->dd_child_dir_zapobj,
1265             dd->dd_myname, 8, 1, &dd->dd_object, tx);
1266         ASSERT3U(err, ==, 0);
1267
1268         spa_history_internal_log(LOG_DS_RENAME, dd->dd_pool->dp_spa,
1269             tx, cr, "dataset = %llu", dd->dd_phys->dd_head_dataset_obj);
1270 }
1271
1272 int
1273 dsl_dir_rename(dsl_dir_t *dd, const char *newname)
1274 {
1275         struct renamearg ra;
1276         int err;
1277
1278         /* new parent should exist */
1279         err = dsl_dir_open(newname, FTAG, &ra.newparent, &ra.mynewname);
1280         if (err)
1281                 return (err);
1282
1283         /* can't rename to different pool */
1284         if (dd->dd_pool != ra.newparent->dd_pool) {
1285                 err = ENXIO;
1286                 goto out;
1287         }
1288
1289         /* new name should not already exist */
1290         if (ra.mynewname == NULL) {
1291                 err = EEXIST;
1292                 goto out;
1293         }
1294
1295         err = dsl_sync_task_do(dd->dd_pool,
1296             dsl_dir_rename_check, dsl_dir_rename_sync, dd, &ra, 3);
1297
1298 out:
1299         dsl_dir_close(ra.newparent, FTAG);
1300         return (err);
1301 }
1302
1303 int
1304 dsl_dir_transfer_possible(dsl_dir_t *sdd, dsl_dir_t *tdd, uint64_t space)
1305 {
1306         dsl_dir_t *ancestor;
1307         int64_t adelta;
1308         uint64_t avail;
1309
1310         ancestor = closest_common_ancestor(sdd, tdd);
1311         adelta = would_change(sdd, -space, ancestor);
1312         avail = dsl_dir_space_available(tdd, ancestor, adelta, FALSE);
1313         if (avail < space)
1314                 return (ENOSPC);
1315
1316         return (0);
1317 }