initial commit
[freebsd-arm:freebsd-arm.git] / 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 2008 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                 int err;
100
101                 dd = kmem_zalloc(sizeof (dsl_dir_t), KM_SLEEP);
102                 dd->dd_object = ddobj;
103                 dd->dd_dbuf = dbuf;
104                 dd->dd_pool = dp;
105                 dd->dd_phys = dbuf->db_data;
106                 mutex_init(&dd->dd_lock, NULL, MUTEX_DEFAULT, NULL);
107
108                 list_create(&dd->dd_prop_cbs, sizeof (dsl_prop_cb_record_t),
109                     offsetof(dsl_prop_cb_record_t, cbr_node));
110
111                 if (dd->dd_phys->dd_parent_obj) {
112                         err = dsl_dir_open_obj(dp, dd->dd_phys->dd_parent_obj,
113                             NULL, dd, &dd->dd_parent);
114                         if (err)
115                                 goto errout;
116                         if (tail) {
117 #ifdef ZFS_DEBUG
118                                 uint64_t foundobj;
119
120                                 err = zap_lookup(dp->dp_meta_objset,
121                                     dd->dd_parent->dd_phys->dd_child_dir_zapobj,
122                                     tail, sizeof (foundobj), 1, &foundobj);
123                                 ASSERT(err || foundobj == ddobj);
124 #endif
125                                 (void) strcpy(dd->dd_myname, tail);
126                         } else {
127                                 err = zap_value_search(dp->dp_meta_objset,
128                                     dd->dd_parent->dd_phys->dd_child_dir_zapobj,
129                                     ddobj, 0, dd->dd_myname);
130                         }
131                         if (err)
132                                 goto errout;
133                 } else {
134                         (void) strcpy(dd->dd_myname, spa_name(dp->dp_spa));
135                 }
136
137                 winner = dmu_buf_set_user_ie(dbuf, dd, &dd->dd_phys,
138                     dsl_dir_evict);
139                 if (winner) {
140                         if (dd->dd_parent)
141                                 dsl_dir_close(dd->dd_parent, dd);
142                         mutex_destroy(&dd->dd_lock);
143                         kmem_free(dd, sizeof (dsl_dir_t));
144                         dd = winner;
145                 } else {
146                         spa_open_ref(dp->dp_spa, dd);
147                 }
148         }
149
150         /*
151          * The dsl_dir_t has both open-to-close and instantiate-to-evict
152          * holds on the spa.  We need the open-to-close holds because
153          * otherwise the spa_refcnt wouldn't change when we open a
154          * dir which the spa also has open, so we could incorrectly
155          * think it was OK to unload/export/destroy the pool.  We need
156          * the instantiate-to-evict hold because the dsl_dir_t has a
157          * pointer to the dd_pool, which has a pointer to the spa_t.
158          */
159         spa_open_ref(dp->dp_spa, tag);
160         ASSERT3P(dd->dd_pool, ==, dp);
161         ASSERT3U(dd->dd_object, ==, ddobj);
162         ASSERT3P(dd->dd_dbuf, ==, dbuf);
163         *ddp = dd;
164         return (0);
165
166 errout:
167         if (dd->dd_parent)
168                 dsl_dir_close(dd->dd_parent, dd);
169         mutex_destroy(&dd->dd_lock);
170         kmem_free(dd, sizeof (dsl_dir_t));
171         dmu_buf_rele(dbuf, tag);
172         return (err);
173
174 }
175
176 void
177 dsl_dir_close(dsl_dir_t *dd, void *tag)
178 {
179         dprintf_dd(dd, "%s\n", "");
180         spa_close(dd->dd_pool->dp_spa, tag);
181         dmu_buf_rele(dd->dd_dbuf, tag);
182 }
183
184 /* buf must be long enough (MAXNAMELEN + strlen(MOS_DIR_NAME) + 1 should do) */
185 void
186 dsl_dir_name(dsl_dir_t *dd, char *buf)
187 {
188         if (dd->dd_parent) {
189                 dsl_dir_name(dd->dd_parent, buf);
190                 (void) strcat(buf, "/");
191         } else {
192                 buf[0] = '\0';
193         }
194         if (!MUTEX_HELD(&dd->dd_lock)) {
195                 /*
196                  * recursive mutex so that we can use
197                  * dprintf_dd() with dd_lock held
198                  */
199                 mutex_enter(&dd->dd_lock);
200                 (void) strcat(buf, dd->dd_myname);
201                 mutex_exit(&dd->dd_lock);
202         } else {
203                 (void) strcat(buf, dd->dd_myname);
204         }
205 }
206
207 /* Calculate name legnth, avoiding all the strcat calls of dsl_dir_name */
208 int
209 dsl_dir_namelen(dsl_dir_t *dd)
210 {
211         int result = 0;
212
213         if (dd->dd_parent) {
214                 /* parent's name + 1 for the "/" */
215                 result = dsl_dir_namelen(dd->dd_parent) + 1;
216         }
217
218         if (!MUTEX_HELD(&dd->dd_lock)) {
219                 /* see dsl_dir_name */
220                 mutex_enter(&dd->dd_lock);
221                 result += strlen(dd->dd_myname);
222                 mutex_exit(&dd->dd_lock);
223         } else {
224                 result += strlen(dd->dd_myname);
225         }
226
227         return (result);
228 }
229
230 int
231 dsl_dir_is_private(dsl_dir_t *dd)
232 {
233         int rv = FALSE;
234
235         if (dd->dd_parent && dsl_dir_is_private(dd->dd_parent))
236                 rv = TRUE;
237         if (dataset_name_hidden(dd->dd_myname))
238                 rv = TRUE;
239         return (rv);
240 }
241
242
243 static int
244 getcomponent(const char *path, char *component, const char **nextp)
245 {
246         char *p;
247         if (path == NULL)
248                 return (ENOENT);
249         /* This would be a good place to reserve some namespace... */
250         p = strpbrk(path, "/@");
251         if (p && (p[1] == '/' || p[1] == '@')) {
252                 /* two separators in a row */
253                 return (EINVAL);
254         }
255         if (p == NULL || p == path) {
256                 /*
257                  * if the first thing is an @ or /, it had better be an
258                  * @ and it had better not have any more ats or slashes,
259                  * and it had better have something after the @.
260                  */
261                 if (p != NULL &&
262                     (p[0] != '@' || strpbrk(path+1, "/@") || p[1] == '\0'))
263                         return (EINVAL);
264                 if (strlen(path) >= MAXNAMELEN)
265                         return (ENAMETOOLONG);
266                 (void) strcpy(component, path);
267                 p = NULL;
268         } else if (p[0] == '/') {
269                 if (p-path >= MAXNAMELEN)
270                         return (ENAMETOOLONG);
271                 (void) strncpy(component, path, p - path);
272                 component[p-path] = '\0';
273                 p++;
274         } else if (p[0] == '@') {
275                 /*
276                  * if the next separator is an @, there better not be
277                  * any more slashes.
278                  */
279                 if (strchr(path, '/'))
280                         return (EINVAL);
281                 if (p-path >= MAXNAMELEN)
282                         return (ENAMETOOLONG);
283                 (void) strncpy(component, path, p - path);
284                 component[p-path] = '\0';
285         } else {
286                 ASSERT(!"invalid p");
287         }
288         *nextp = p;
289         return (0);
290 }
291
292 /*
293  * same as dsl_open_dir, ignore the first component of name and use the
294  * spa instead
295  */
296 int
297 dsl_dir_open_spa(spa_t *spa, const char *name, void *tag,
298     dsl_dir_t **ddp, const char **tailp)
299 {
300         char buf[MAXNAMELEN];
301         const char *next, *nextnext = NULL;
302         int err;
303         dsl_dir_t *dd;
304         dsl_pool_t *dp;
305         uint64_t ddobj;
306         int openedspa = FALSE;
307
308         dprintf("%s\n", name);
309
310         err = getcomponent(name, buf, &next);
311         if (err)
312                 return (err);
313         if (spa == NULL) {
314                 err = spa_open(buf, &spa, FTAG);
315                 if (err) {
316                         dprintf("spa_open(%s) failed\n", buf);
317                         return (err);
318                 }
319                 openedspa = TRUE;
320
321                 /* XXX this assertion belongs in spa_open */
322                 ASSERT(!dsl_pool_sync_context(spa_get_dsl(spa)));
323         }
324
325         dp = spa_get_dsl(spa);
326
327         rw_enter(&dp->dp_config_rwlock, RW_READER);
328         err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj, NULL, tag, &dd);
329         if (err) {
330                 rw_exit(&dp->dp_config_rwlock);
331                 if (openedspa)
332                         spa_close(spa, FTAG);
333                 return (err);
334         }
335
336         while (next != NULL) {
337                 dsl_dir_t *child_ds;
338                 err = getcomponent(next, buf, &nextnext);
339                 if (err)
340                         break;
341                 ASSERT(next[0] != '\0');
342                 if (next[0] == '@')
343                         break;
344                 dprintf("looking up %s in obj%lld\n",
345                     buf, dd->dd_phys->dd_child_dir_zapobj);
346
347                 err = zap_lookup(dp->dp_meta_objset,
348                     dd->dd_phys->dd_child_dir_zapobj,
349                     buf, sizeof (ddobj), 1, &ddobj);
350                 if (err) {
351                         if (err == ENOENT)
352                                 err = 0;
353                         break;
354                 }
355
356                 err = dsl_dir_open_obj(dp, ddobj, buf, tag, &child_ds);
357                 if (err)
358                         break;
359                 dsl_dir_close(dd, tag);
360                 dd = child_ds;
361                 next = nextnext;
362         }
363         rw_exit(&dp->dp_config_rwlock);
364
365         if (err) {
366                 dsl_dir_close(dd, tag);
367                 if (openedspa)
368                         spa_close(spa, FTAG);
369                 return (err);
370         }
371
372         /*
373          * It's an error if there's more than one component left, or
374          * tailp==NULL and there's any component left.
375          */
376         if (next != NULL &&
377             (tailp == NULL || (nextnext && nextnext[0] != '\0'))) {
378                 /* bad path name */
379                 dsl_dir_close(dd, tag);
380                 dprintf("next=%p (%s) tail=%p\n", next, next?next:"", tailp);
381                 err = ENOENT;
382         }
383         if (tailp)
384                 *tailp = next;
385         if (openedspa)
386                 spa_close(spa, FTAG);
387         *ddp = dd;
388         return (err);
389 }
390
391 /*
392  * Return the dsl_dir_t, and possibly the last component which couldn't
393  * be found in *tail.  Return NULL if the path is bogus, or if
394  * tail==NULL and we couldn't parse the whole name.  (*tail)[0] == '@'
395  * means that the last component is a snapshot.
396  */
397 int
398 dsl_dir_open(const char *name, void *tag, dsl_dir_t **ddp, const char **tailp)
399 {
400         return (dsl_dir_open_spa(NULL, name, tag, ddp, tailp));
401 }
402
403 uint64_t
404 dsl_dir_create_sync(dsl_pool_t *dp, dsl_dir_t *pds, const char *name,
405     dmu_tx_t *tx)
406 {
407         objset_t *mos = dp->dp_meta_objset;
408         uint64_t ddobj;
409         dsl_dir_phys_t *dsphys;
410         dmu_buf_t *dbuf;
411
412         ddobj = dmu_object_alloc(mos, DMU_OT_DSL_DIR, 0,
413             DMU_OT_DSL_DIR, sizeof (dsl_dir_phys_t), tx);
414         if (pds) {
415                 VERIFY(0 == zap_add(mos, pds->dd_phys->dd_child_dir_zapobj,
416                     name, sizeof (uint64_t), 1, &ddobj, tx));
417         } else {
418                 /* it's the root dir */
419                 VERIFY(0 == zap_add(mos, DMU_POOL_DIRECTORY_OBJECT,
420                     DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1, &ddobj, tx));
421         }
422         VERIFY(0 == dmu_bonus_hold(mos, ddobj, FTAG, &dbuf));
423         dmu_buf_will_dirty(dbuf, tx);
424         dsphys = dbuf->db_data;
425
426         dsphys->dd_creation_time = gethrestime_sec();
427         if (pds)
428                 dsphys->dd_parent_obj = pds->dd_object;
429         dsphys->dd_props_zapobj = zap_create(mos,
430             DMU_OT_DSL_PROPS, DMU_OT_NONE, 0, tx);
431         dsphys->dd_child_dir_zapobj = zap_create(mos,
432             DMU_OT_DSL_DIR_CHILD_MAP, DMU_OT_NONE, 0, tx);
433         if (spa_version(dp->dp_spa) >= SPA_VERSION_USED_BREAKDOWN)
434                 dsphys->dd_flags |= DD_FLAG_USED_BREAKDOWN;
435         dmu_buf_rele(dbuf, FTAG);
436
437         return (ddobj);
438 }
439
440 /* ARGSUSED */
441 int
442 dsl_dir_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx)
443 {
444         dsl_dir_t *dd = arg1;
445         dsl_pool_t *dp = dd->dd_pool;
446         objset_t *mos = dp->dp_meta_objset;
447         int err;
448         uint64_t count;
449
450         /*
451          * There should be exactly two holds, both from
452          * dsl_dataset_destroy: one on the dd directory, and one on its
453          * head ds.  Otherwise, someone is trying to lookup something
454          * inside this dir while we want to destroy it.  The
455          * config_rwlock ensures that nobody else opens it after we
456          * check.
457          */
458         if (dmu_buf_refcount(dd->dd_dbuf) > 2)
459                 return (EBUSY);
460
461         err = zap_count(mos, dd->dd_phys->dd_child_dir_zapobj, &count);
462         if (err)
463                 return (err);
464         if (count != 0)
465                 return (EEXIST);
466
467         return (0);
468 }
469
470 void
471 dsl_dir_destroy_sync(void *arg1, void *tag, cred_t *cr, dmu_tx_t *tx)
472 {
473         dsl_dir_t *dd = arg1;
474         objset_t *mos = dd->dd_pool->dp_meta_objset;
475         uint64_t val, obj;
476         dd_used_t t;
477
478         ASSERT(RW_WRITE_HELD(&dd->dd_pool->dp_config_rwlock));
479         ASSERT(dd->dd_phys->dd_head_dataset_obj == 0);
480
481         /* Remove our reservation. */
482         val = 0;
483         dsl_dir_set_reservation_sync(dd, &val, cr, tx);
484         ASSERT3U(dd->dd_phys->dd_used_bytes, ==, 0);
485         ASSERT3U(dd->dd_phys->dd_reserved, ==, 0);
486         for (t = 0; t < DD_USED_NUM; t++)
487                 ASSERT3U(dd->dd_phys->dd_used_breakdown[t], ==, 0);
488
489         VERIFY(0 == zap_destroy(mos, dd->dd_phys->dd_child_dir_zapobj, tx));
490         VERIFY(0 == zap_destroy(mos, dd->dd_phys->dd_props_zapobj, tx));
491         VERIFY(0 == dsl_deleg_destroy(mos, dd->dd_phys->dd_deleg_zapobj, tx));
492         VERIFY(0 == zap_remove(mos,
493             dd->dd_parent->dd_phys->dd_child_dir_zapobj, dd->dd_myname, tx));
494
495         obj = dd->dd_object;
496         dsl_dir_close(dd, tag);
497         VERIFY(0 == dmu_object_free(mos, obj, tx));
498 }
499
500 boolean_t
501 dsl_dir_is_clone(dsl_dir_t *dd)
502 {
503         return (dd->dd_phys->dd_origin_obj &&
504             (dd->dd_pool->dp_origin_snap == NULL ||
505             dd->dd_phys->dd_origin_obj !=
506             dd->dd_pool->dp_origin_snap->ds_object));
507 }
508
509 void
510 dsl_dir_stats(dsl_dir_t *dd, nvlist_t *nv)
511 {
512         mutex_enter(&dd->dd_lock);
513         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
514             dd->dd_phys->dd_used_bytes);
515         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_QUOTA, dd->dd_phys->dd_quota);
516         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_RESERVATION,
517             dd->dd_phys->dd_reserved);
518         dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
519             dd->dd_phys->dd_compressed_bytes == 0 ? 100 :
520             (dd->dd_phys->dd_uncompressed_bytes * 100 /
521             dd->dd_phys->dd_compressed_bytes));
522         if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
523                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDSNAP,
524                     dd->dd_phys->dd_used_breakdown[DD_USED_SNAP]);
525                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDDS,
526                     dd->dd_phys->dd_used_breakdown[DD_USED_HEAD]);
527                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDREFRESERV,
528                     dd->dd_phys->dd_used_breakdown[DD_USED_REFRSRV]);
529                 dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USEDCHILD,
530                     dd->dd_phys->dd_used_breakdown[DD_USED_CHILD] +
531                     dd->dd_phys->dd_used_breakdown[DD_USED_CHILD_RSRV]);
532         }
533         mutex_exit(&dd->dd_lock);
534
535         rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
536         if (dsl_dir_is_clone(dd)) {
537                 dsl_dataset_t *ds;
538                 char buf[MAXNAMELEN];
539
540                 VERIFY(0 == dsl_dataset_hold_obj(dd->dd_pool,
541                     dd->dd_phys->dd_origin_obj, FTAG, &ds));
542                 dsl_dataset_name(ds, buf);
543                 dsl_dataset_rele(ds, FTAG);
544                 dsl_prop_nvlist_add_string(nv, ZFS_PROP_ORIGIN, buf);
545         }
546         rw_exit(&dd->dd_pool->dp_config_rwlock);
547 }
548
549 void
550 dsl_dir_dirty(dsl_dir_t *dd, dmu_tx_t *tx)
551 {
552         dsl_pool_t *dp = dd->dd_pool;
553
554         ASSERT(dd->dd_phys);
555
556         if (txg_list_add(&dp->dp_dirty_dirs, dd, tx->tx_txg) == 0) {
557                 /* up the hold count until we can be written out */
558                 dmu_buf_add_ref(dd->dd_dbuf, dd);
559         }
560 }
561
562 static int64_t
563 parent_delta(dsl_dir_t *dd, uint64_t used, int64_t delta)
564 {
565         uint64_t old_accounted = MAX(used, dd->dd_phys->dd_reserved);
566         uint64_t new_accounted = MAX(used + delta, dd->dd_phys->dd_reserved);
567         return (new_accounted - old_accounted);
568 }
569
570 void
571 dsl_dir_sync(dsl_dir_t *dd, dmu_tx_t *tx)
572 {
573         ASSERT(dmu_tx_is_syncing(tx));
574
575         dmu_buf_will_dirty(dd->dd_dbuf, tx);
576
577         mutex_enter(&dd->dd_lock);
578         ASSERT3U(dd->dd_tempreserved[tx->tx_txg&TXG_MASK], ==, 0);
579         dprintf_dd(dd, "txg=%llu towrite=%lluK\n", tx->tx_txg,
580             dd->dd_space_towrite[tx->tx_txg&TXG_MASK] / 1024);
581         dd->dd_space_towrite[tx->tx_txg&TXG_MASK] = 0;
582         mutex_exit(&dd->dd_lock);
583
584         /* release the hold from dsl_dir_dirty */
585         dmu_buf_rele(dd->dd_dbuf, dd);
586 }
587
588 static uint64_t
589 dsl_dir_space_towrite(dsl_dir_t *dd)
590 {
591         uint64_t space = 0;
592         int i;
593
594         ASSERT(MUTEX_HELD(&dd->dd_lock));
595
596         for (i = 0; i < TXG_SIZE; i++) {
597                 space += dd->dd_space_towrite[i&TXG_MASK];
598                 ASSERT3U(dd->dd_space_towrite[i&TXG_MASK], >=, 0);
599         }
600         return (space);
601 }
602
603 /*
604  * How much space would dd have available if ancestor had delta applied
605  * to it?  If ondiskonly is set, we're only interested in what's
606  * on-disk, not estimated pending changes.
607  */
608 uint64_t
609 dsl_dir_space_available(dsl_dir_t *dd,
610     dsl_dir_t *ancestor, int64_t delta, int ondiskonly)
611 {
612         uint64_t parentspace, myspace, quota, used;
613
614         /*
615          * If there are no restrictions otherwise, assume we have
616          * unlimited space available.
617          */
618         quota = UINT64_MAX;
619         parentspace = UINT64_MAX;
620
621         if (dd->dd_parent != NULL) {
622                 parentspace = dsl_dir_space_available(dd->dd_parent,
623                     ancestor, delta, ondiskonly);
624         }
625
626         mutex_enter(&dd->dd_lock);
627         if (dd->dd_phys->dd_quota != 0)
628                 quota = dd->dd_phys->dd_quota;
629         used = dd->dd_phys->dd_used_bytes;
630         if (!ondiskonly)
631                 used += dsl_dir_space_towrite(dd);
632
633         if (dd->dd_parent == NULL) {
634                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, FALSE);
635                 quota = MIN(quota, poolsize);
636         }
637
638         if (dd->dd_phys->dd_reserved > used && parentspace != UINT64_MAX) {
639                 /*
640                  * We have some space reserved, in addition to what our
641                  * parent gave us.
642                  */
643                 parentspace += dd->dd_phys->dd_reserved - used;
644         }
645
646         if (dd == ancestor) {
647                 ASSERT(delta <= 0);
648                 ASSERT(used >= -delta);
649                 used += delta;
650                 if (parentspace != UINT64_MAX)
651                         parentspace -= delta;
652         }
653
654         if (used > quota) {
655                 /* over quota */
656                 myspace = 0;
657
658                 /*
659                  * While it's OK to be a little over quota, if
660                  * we think we are using more space than there
661                  * is in the pool (which is already 1.6% more than
662                  * dsl_pool_adjustedsize()), something is very
663                  * wrong.
664                  */
665                 ASSERT3U(used, <=, spa_get_space(dd->dd_pool->dp_spa));
666         } else {
667                 /*
668                  * the lesser of the space provided by our parent and
669                  * the space left in our quota
670                  */
671                 myspace = MIN(parentspace, quota - used);
672         }
673
674         mutex_exit(&dd->dd_lock);
675
676         return (myspace);
677 }
678
679 struct tempreserve {
680         list_node_t tr_node;
681         dsl_pool_t *tr_dp;
682         dsl_dir_t *tr_ds;
683         uint64_t tr_size;
684 };
685
686 static int
687 dsl_dir_tempreserve_impl(dsl_dir_t *dd, uint64_t asize, boolean_t netfree,
688     boolean_t ignorequota, boolean_t checkrefquota, list_t *tr_list,
689     dmu_tx_t *tx, boolean_t first)
690 {
691         uint64_t txg = tx->tx_txg;
692         uint64_t est_inflight, used_on_disk, quota, parent_rsrv;
693         struct tempreserve *tr;
694         int enospc = EDQUOT;
695         int txgidx = txg & TXG_MASK;
696         int i;
697         uint64_t ref_rsrv = 0;
698
699         ASSERT3U(txg, !=, 0);
700         ASSERT3S(asize, >, 0);
701
702         mutex_enter(&dd->dd_lock);
703
704         /*
705          * Check against the dsl_dir's quota.  We don't add in the delta
706          * when checking for over-quota because they get one free hit.
707          */
708         est_inflight = dsl_dir_space_towrite(dd);
709         for (i = 0; i < TXG_SIZE; i++)
710                 est_inflight += dd->dd_tempreserved[i];
711         used_on_disk = dd->dd_phys->dd_used_bytes;
712
713         /*
714          * On the first iteration, fetch the dataset's used-on-disk and
715          * refreservation values. Also, if checkrefquota is set, test if
716          * allocating this space would exceed the dataset's refquota.
717          */
718         if (first && tx->tx_objset) {
719                 int error;
720                 dsl_dataset_t *ds = tx->tx_objset->os->os_dsl_dataset;
721
722                 error = dsl_dataset_check_quota(ds, checkrefquota,
723                     asize, est_inflight, &used_on_disk, &ref_rsrv);
724                 if (error) {
725                         mutex_exit(&dd->dd_lock);
726                         return (error);
727                 }
728         }
729
730         /*
731          * If this transaction will result in a net free of space,
732          * we want to let it through.
733          */
734         if (ignorequota || netfree || dd->dd_phys->dd_quota == 0)
735                 quota = UINT64_MAX;
736         else
737                 quota = dd->dd_phys->dd_quota;
738
739         /*
740          * Adjust the quota against the actual pool size at the root.
741          * To ensure that it's possible to remove files from a full
742          * pool without inducing transient overcommits, we throttle
743          * netfree transactions against a quota that is slightly larger,
744          * but still within the pool's allocation slop.  In cases where
745          * we're very close to full, this will allow a steady trickle of
746          * removes to get through.
747          */
748         if (dd->dd_parent == NULL) {
749                 uint64_t poolsize = dsl_pool_adjustedsize(dd->dd_pool, netfree);
750                 if (poolsize < quota) {
751                         quota = poolsize;
752                         enospc = ENOSPC;
753                 }
754         }
755
756         /*
757          * If they are requesting more space, and our current estimate
758          * is over quota, they get to try again unless the actual
759          * on-disk is over quota and there are no pending changes (which
760          * may free up space for us).
761          */
762         if (used_on_disk + est_inflight > quota) {
763                 if (est_inflight > 0 || used_on_disk < quota)
764                         enospc = ERESTART;
765                 dprintf_dd(dd, "failing: used=%lluK inflight = %lluK "
766                     "quota=%lluK tr=%lluK err=%d\n",
767                     used_on_disk>>10, est_inflight>>10,
768                     quota>>10, asize>>10, enospc);
769                 mutex_exit(&dd->dd_lock);
770                 return (enospc);
771         }
772
773         /* We need to up our estimated delta before dropping dd_lock */
774         dd->dd_tempreserved[txgidx] += asize;
775
776         parent_rsrv = parent_delta(dd, used_on_disk + est_inflight,
777             asize - ref_rsrv);
778         mutex_exit(&dd->dd_lock);
779
780         tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
781         tr->tr_ds = dd;
782         tr->tr_size = asize;
783         list_insert_tail(tr_list, tr);
784
785         /* see if it's OK with our parent */
786         if (dd->dd_parent && parent_rsrv) {
787                 boolean_t ismos = (dd->dd_phys->dd_head_dataset_obj == 0);
788
789                 return (dsl_dir_tempreserve_impl(dd->dd_parent,
790                     parent_rsrv, netfree, ismos, TRUE, tr_list, tx, FALSE));
791         } else {
792                 return (0);
793         }
794 }
795
796 /*
797  * Reserve space in this dsl_dir, to be used in this tx's txg.
798  * After the space has been dirtied (and dsl_dir_willuse_space()
799  * has been called), the reservation should be canceled, using
800  * dsl_dir_tempreserve_clear().
801  */
802 int
803 dsl_dir_tempreserve_space(dsl_dir_t *dd, uint64_t lsize, uint64_t asize,
804     uint64_t fsize, uint64_t usize, void **tr_cookiep, dmu_tx_t *tx)
805 {
806         int err;
807         list_t *tr_list;
808
809         if (asize == 0) {
810                 *tr_cookiep = NULL;
811                 return (0);
812         }
813
814         tr_list = kmem_alloc(sizeof (list_t), KM_SLEEP);
815         list_create(tr_list, sizeof (struct tempreserve),
816             offsetof(struct tempreserve, tr_node));
817         ASSERT3S(asize, >, 0);
818         ASSERT3S(fsize, >=, 0);
819
820         err = arc_tempreserve_space(lsize, tx->tx_txg);
821         if (err == 0) {
822                 struct tempreserve *tr;
823
824                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
825                 tr->tr_size = lsize;
826                 list_insert_tail(tr_list, tr);
827
828                 err = dsl_pool_tempreserve_space(dd->dd_pool, asize, tx);
829         } else {
830                 if (err == EAGAIN) {
831                         txg_delay(dd->dd_pool, tx->tx_txg, 1);
832                         err = ERESTART;
833                 }
834                 dsl_pool_memory_pressure(dd->dd_pool);
835         }
836
837         if (err == 0) {
838                 struct tempreserve *tr;
839
840                 tr = kmem_zalloc(sizeof (struct tempreserve), KM_SLEEP);
841                 tr->tr_dp = dd->dd_pool;
842                 tr->tr_size = asize;
843                 list_insert_tail(tr_list, tr);
844
845                 err = dsl_dir_tempreserve_impl(dd, asize, fsize >= asize,
846                     FALSE, asize > usize, tr_list, tx, TRUE);
847         }
848
849         if (err)
850                 dsl_dir_tempreserve_clear(tr_list, tx);
851         else
852                 *tr_cookiep = tr_list;
853
854         return (err);
855 }
856
857 /*
858  * Clear a temporary reservation that we previously made with
859  * dsl_dir_tempreserve_space().
860  */
861 void
862 dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
863 {
864         int txgidx = tx->tx_txg & TXG_MASK;
865         list_t *tr_list = tr_cookie;
866         struct tempreserve *tr;
867
868         ASSERT3U(tx->tx_txg, !=, 0);
869
870         if (tr_cookie == NULL)
871                 return;
872
873         while (tr = list_head(tr_list)) {
874                 if (tr->tr_dp) {
875                         dsl_pool_tempreserve_clear(tr->tr_dp, tr->tr_size, tx);
876                 } else if (tr->tr_ds) {
877                         mutex_enter(&tr->tr_ds->dd_lock);
878                         ASSERT3U(tr->tr_ds->dd_tempreserved[txgidx], >=,
879                             tr->tr_size);
880                         tr->tr_ds->dd_tempreserved[txgidx] -= tr->tr_size;
881                         mutex_exit(&tr->tr_ds->dd_lock);
882                 } else {
883                         arc_tempreserve_clear(tr->tr_size);
884                 }
885                 list_remove(tr_list, tr);
886                 kmem_free(tr, sizeof (struct tempreserve));
887         }
888
889         kmem_free(tr_list, sizeof (list_t));
890 }
891
892 static void
893 dsl_dir_willuse_space_impl(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
894 {
895         int64_t parent_space;
896         uint64_t est_used;
897
898         mutex_enter(&dd->dd_lock);
899         if (space > 0)
900                 dd->dd_space_towrite[tx->tx_txg & TXG_MASK] += space;
901
902         est_used = dsl_dir_space_towrite(dd) + dd->dd_phys->dd_used_bytes;
903         parent_space = parent_delta(dd, est_used, space);
904         mutex_exit(&dd->dd_lock);
905
906         /* Make sure that we clean up dd_space_to* */
907         dsl_dir_dirty(dd, tx);
908
909         /* XXX this is potentially expensive and unnecessary... */
910         if (parent_space && dd->dd_parent)
911                 dsl_dir_willuse_space_impl(dd->dd_parent, parent_space, tx);
912 }
913
914 /*
915  * Call in open context when we think we're going to write/free space,
916  * eg. when dirtying data.  Be conservative (ie. OK to write less than
917  * this or free more than this, but don't write more or free less).
918  */
919 void
920 dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
921 {
922         dsl_pool_willuse_space(dd->dd_pool, space, tx);
923         dsl_dir_willuse_space_impl(dd, space, tx);
924 }
925
926 /* call from syncing context when we actually write/free space for this dd */
927 void
928 dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
929     int64_t used, int64_t compressed, int64_t uncompressed, dmu_tx_t *tx)
930 {
931         int64_t accounted_delta;
932         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
933
934         ASSERT(dmu_tx_is_syncing(tx));
935         ASSERT(type < DD_USED_NUM);
936
937         dsl_dir_dirty(dd, tx);
938
939         if (needlock)
940                 mutex_enter(&dd->dd_lock);
941         accounted_delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, used);
942         ASSERT(used >= 0 || dd->dd_phys->dd_used_bytes >= -used);
943         ASSERT(compressed >= 0 ||
944             dd->dd_phys->dd_compressed_bytes >= -compressed);
945         ASSERT(uncompressed >= 0 ||
946             dd->dd_phys->dd_uncompressed_bytes >= -uncompressed);
947         dd->dd_phys->dd_used_bytes += used;
948         dd->dd_phys->dd_uncompressed_bytes += uncompressed;
949         dd->dd_phys->dd_compressed_bytes += compressed;
950
951         if (dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN) {
952                 ASSERT(used > 0 ||
953                     dd->dd_phys->dd_used_breakdown[type] >= -used);
954                 dd->dd_phys->dd_used_breakdown[type] += used;
955 #ifdef DEBUG
956                 dd_used_t t;
957                 uint64_t u = 0;
958                 for (t = 0; t < DD_USED_NUM; t++)
959                         u += dd->dd_phys->dd_used_breakdown[t];
960                 ASSERT3U(u, ==, dd->dd_phys->dd_used_bytes);
961 #endif
962         }
963         if (needlock)
964                 mutex_exit(&dd->dd_lock);
965
966         if (dd->dd_parent != NULL) {
967                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
968                     accounted_delta, compressed, uncompressed, tx);
969                 dsl_dir_transfer_space(dd->dd_parent,
970                     used - accounted_delta,
971                     DD_USED_CHILD_RSRV, DD_USED_CHILD, tx);
972         }
973 }
974
975 void
976 dsl_dir_transfer_space(dsl_dir_t *dd, int64_t delta,
977     dd_used_t oldtype, dd_used_t newtype, dmu_tx_t *tx)
978 {
979         boolean_t needlock = !MUTEX_HELD(&dd->dd_lock);
980
981         ASSERT(dmu_tx_is_syncing(tx));
982         ASSERT(oldtype < DD_USED_NUM);
983         ASSERT(newtype < DD_USED_NUM);
984
985         if (delta == 0 || !(dd->dd_phys->dd_flags & DD_FLAG_USED_BREAKDOWN))
986                 return;
987
988         dsl_dir_dirty(dd, tx);
989         if (needlock)
990                 mutex_enter(&dd->dd_lock);
991         ASSERT(delta > 0 ?
992             dd->dd_phys->dd_used_breakdown[oldtype] >= delta :
993             dd->dd_phys->dd_used_breakdown[newtype] >= -delta);
994         ASSERT(dd->dd_phys->dd_used_bytes >= ABS(delta));
995         dd->dd_phys->dd_used_breakdown[oldtype] -= delta;
996         dd->dd_phys->dd_used_breakdown[newtype] += delta;
997         if (needlock)
998                 mutex_exit(&dd->dd_lock);
999 }
1000
1001 static int
1002 dsl_dir_set_quota_check(void *arg1, void *arg2, dmu_tx_t *tx)
1003 {
1004         dsl_dir_t *dd = arg1;
1005         uint64_t *quotap = arg2;
1006         uint64_t new_quota = *quotap;
1007         int err = 0;
1008         uint64_t towrite;
1009
1010         if (new_quota == 0)
1011                 return (0);
1012
1013         mutex_enter(&dd->dd_lock);
1014         /*
1015          * If we are doing the preliminary check in open context, and
1016          * there are pending changes, then don't fail it, since the
1017          * pending changes could under-estimate the amount of space to be
1018          * freed up.
1019          */
1020         towrite = dsl_dir_space_towrite(dd);
1021         if ((dmu_tx_is_syncing(tx) || towrite == 0) &&
1022             (new_quota < dd->dd_phys->dd_reserved ||
1023             new_quota < dd->dd_phys->dd_used_bytes + towrite)) {
1024                 err = ENOSPC;
1025         }
1026         mutex_exit(&dd->dd_lock);
1027         return (err);
1028 }
1029
1030 /* ARGSUSED */
1031 static void
1032 dsl_dir_set_quota_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1033 {
1034         dsl_dir_t *dd = arg1;
1035         uint64_t *quotap = arg2;
1036         uint64_t new_quota = *quotap;
1037
1038         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1039
1040         mutex_enter(&dd->dd_lock);
1041         dd->dd_phys->dd_quota = new_quota;
1042         mutex_exit(&dd->dd_lock);
1043
1044         spa_history_internal_log(LOG_DS_QUOTA, dd->dd_pool->dp_spa,
1045             tx, cr, "%lld dataset = %llu ",
1046             (longlong_t)new_quota, dd->dd_phys->dd_head_dataset_obj);
1047 }
1048
1049 int
1050 dsl_dir_set_quota(const char *ddname, uint64_t quota)
1051 {
1052         dsl_dir_t *dd;
1053         int err;
1054
1055         err = dsl_dir_open(ddname, FTAG, &dd, NULL);
1056         if (err)
1057                 return (err);
1058
1059         if (quota != dd->dd_phys->dd_quota) {
1060                 /*
1061                  * If someone removes a file, then tries to set the quota, we
1062                  * want to make sure the file freeing takes effect.
1063                  */
1064                 txg_wait_open(dd->dd_pool, 0);
1065
1066                 err = dsl_sync_task_do(dd->dd_pool, dsl_dir_set_quota_check,
1067                     dsl_dir_set_quota_sync, dd, &quota, 0);
1068         }
1069         dsl_dir_close(dd, FTAG);
1070         return (err);
1071 }
1072
1073 int
1074 dsl_dir_set_reservation_check(void *arg1, void *arg2, dmu_tx_t *tx)
1075 {
1076         dsl_dir_t *dd = arg1;
1077         uint64_t *reservationp = arg2;
1078         uint64_t new_reservation = *reservationp;
1079         uint64_t used, avail;
1080         int64_t delta;
1081
1082         if (new_reservation > INT64_MAX)
1083                 return (EOVERFLOW);
1084
1085         /*
1086          * If we are doing the preliminary check in open context, the
1087          * space estimates may be inaccurate.
1088          */
1089         if (!dmu_tx_is_syncing(tx))
1090                 return (0);
1091
1092         mutex_enter(&dd->dd_lock);
1093         used = dd->dd_phys->dd_used_bytes;
1094         delta = MAX(used, new_reservation) -
1095             MAX(used, dd->dd_phys->dd_reserved);
1096         mutex_exit(&dd->dd_lock);
1097
1098         if (dd->dd_parent) {
1099                 avail = dsl_dir_space_available(dd->dd_parent,
1100                     NULL, 0, FALSE);
1101         } else {
1102                 avail = dsl_pool_adjustedsize(dd->dd_pool, B_FALSE) - used;
1103         }
1104
1105         if (delta > 0 && delta > avail)
1106                 return (ENOSPC);
1107         if (delta > 0 && dd->dd_phys->dd_quota > 0 &&
1108             new_reservation > dd->dd_phys->dd_quota)
1109                 return (ENOSPC);
1110         return (0);
1111 }
1112
1113 /* ARGSUSED */
1114 static void
1115 dsl_dir_set_reservation_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1116 {
1117         dsl_dir_t *dd = arg1;
1118         uint64_t *reservationp = arg2;
1119         uint64_t new_reservation = *reservationp;
1120         uint64_t used;
1121         int64_t delta;
1122
1123         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1124
1125         mutex_enter(&dd->dd_lock);
1126         used = dd->dd_phys->dd_used_bytes;
1127         delta = MAX(used, new_reservation) -
1128             MAX(used, dd->dd_phys->dd_reserved);
1129         dd->dd_phys->dd_reserved = new_reservation;
1130
1131         if (dd->dd_parent != NULL) {
1132                 /* Roll up this additional usage into our ancestors */
1133                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1134                     delta, 0, 0, tx);
1135         }
1136         mutex_exit(&dd->dd_lock);
1137
1138         spa_history_internal_log(LOG_DS_RESERVATION, dd->dd_pool->dp_spa,
1139             tx, cr, "%lld dataset = %llu",
1140             (longlong_t)new_reservation, dd->dd_phys->dd_head_dataset_obj);
1141 }
1142
1143 int
1144 dsl_dir_set_reservation(const char *ddname, uint64_t reservation)
1145 {
1146         dsl_dir_t *dd;
1147         int err;
1148
1149         err = dsl_dir_open(ddname, FTAG, &dd, NULL);
1150         if (err)
1151                 return (err);
1152         err = dsl_sync_task_do(dd->dd_pool, dsl_dir_set_reservation_check,
1153             dsl_dir_set_reservation_sync, dd, &reservation, 0);
1154         dsl_dir_close(dd, FTAG);
1155         return (err);
1156 }
1157
1158 static dsl_dir_t *
1159 closest_common_ancestor(dsl_dir_t *ds1, dsl_dir_t *ds2)
1160 {
1161         for (; ds1; ds1 = ds1->dd_parent) {
1162                 dsl_dir_t *dd;
1163                 for (dd = ds2; dd; dd = dd->dd_parent) {
1164                         if (ds1 == dd)
1165                                 return (dd);
1166                 }
1167         }
1168         return (NULL);
1169 }
1170
1171 /*
1172  * If delta is applied to dd, how much of that delta would be applied to
1173  * ancestor?  Syncing context only.
1174  */
1175 static int64_t
1176 would_change(dsl_dir_t *dd, int64_t delta, dsl_dir_t *ancestor)
1177 {
1178         if (dd == ancestor)
1179                 return (delta);
1180
1181         mutex_enter(&dd->dd_lock);
1182         delta = parent_delta(dd, dd->dd_phys->dd_used_bytes, delta);
1183         mutex_exit(&dd->dd_lock);
1184         return (would_change(dd->dd_parent, delta, ancestor));
1185 }
1186
1187 struct renamearg {
1188         dsl_dir_t *newparent;
1189         const char *mynewname;
1190 };
1191
1192 /*ARGSUSED*/
1193 static int
1194 dsl_dir_rename_check(void *arg1, void *arg2, dmu_tx_t *tx)
1195 {
1196         dsl_dir_t *dd = arg1;
1197         struct renamearg *ra = arg2;
1198         dsl_pool_t *dp = dd->dd_pool;
1199         objset_t *mos = dp->dp_meta_objset;
1200         int err;
1201         uint64_t val;
1202
1203         /* There should be 2 references: the open and the dirty */
1204         if (dmu_buf_refcount(dd->dd_dbuf) > 2)
1205                 return (EBUSY);
1206
1207         /* check for existing name */
1208         err = zap_lookup(mos, ra->newparent->dd_phys->dd_child_dir_zapobj,
1209             ra->mynewname, 8, 1, &val);
1210         if (err == 0)
1211                 return (EEXIST);
1212         if (err != ENOENT)
1213                 return (err);
1214
1215         if (ra->newparent != dd->dd_parent) {
1216                 /* is there enough space? */
1217                 uint64_t myspace =
1218                     MAX(dd->dd_phys->dd_used_bytes, dd->dd_phys->dd_reserved);
1219
1220                 /* no rename into our descendant */
1221                 if (closest_common_ancestor(dd, ra->newparent) == dd)
1222                         return (EINVAL);
1223
1224                 if (err = dsl_dir_transfer_possible(dd->dd_parent,
1225                     ra->newparent, myspace))
1226                         return (err);
1227         }
1228
1229         return (0);
1230 }
1231
1232 static void
1233 dsl_dir_rename_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1234 {
1235         dsl_dir_t *dd = arg1;
1236         struct renamearg *ra = arg2;
1237         dsl_pool_t *dp = dd->dd_pool;
1238         objset_t *mos = dp->dp_meta_objset;
1239         int err;
1240
1241         ASSERT(dmu_buf_refcount(dd->dd_dbuf) <= 2);
1242
1243         if (ra->newparent != dd->dd_parent) {
1244                 dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD,
1245                     -dd->dd_phys->dd_used_bytes,
1246                     -dd->dd_phys->dd_compressed_bytes,
1247                     -dd->dd_phys->dd_uncompressed_bytes, tx);
1248                 dsl_dir_diduse_space(ra->newparent, DD_USED_CHILD,
1249                     dd->dd_phys->dd_used_bytes,
1250                     dd->dd_phys->dd_compressed_bytes,
1251                     dd->dd_phys->dd_uncompressed_bytes, tx);
1252
1253                 if (dd->dd_phys->dd_reserved > dd->dd_phys->dd_used_bytes) {
1254                         uint64_t unused_rsrv = dd->dd_phys->dd_reserved -
1255                             dd->dd_phys->dd_used_bytes;
1256
1257                         dsl_dir_diduse_space(dd->dd_parent, DD_USED_CHILD_RSRV,
1258                             -unused_rsrv, 0, 0, tx);
1259                         dsl_dir_diduse_space(ra->newparent, DD_USED_CHILD_RSRV,
1260                             unused_rsrv, 0, 0, tx);
1261                 }
1262         }
1263
1264         dmu_buf_will_dirty(dd->dd_dbuf, tx);
1265
1266         /* remove from old parent zapobj */
1267         err = zap_remove(mos, dd->dd_parent->dd_phys->dd_child_dir_zapobj,
1268             dd->dd_myname, tx);
1269         ASSERT3U(err, ==, 0);
1270
1271         (void) strcpy(dd->dd_myname, ra->mynewname);
1272         dsl_dir_close(dd->dd_parent, dd);
1273         dd->dd_phys->dd_parent_obj = ra->newparent->dd_object;
1274         VERIFY(0 == dsl_dir_open_obj(dd->dd_pool,
1275             ra->newparent->dd_object, NULL, dd, &dd->dd_parent));
1276
1277         /* add to new parent zapobj */
1278         err = zap_add(mos, ra->newparent->dd_phys->dd_child_dir_zapobj,
1279             dd->dd_myname, 8, 1, &dd->dd_object, tx);
1280         ASSERT3U(err, ==, 0);
1281
1282         spa_history_internal_log(LOG_DS_RENAME, dd->dd_pool->dp_spa,
1283             tx, cr, "dataset = %llu", dd->dd_phys->dd_head_dataset_obj);
1284 }
1285
1286 int
1287 dsl_dir_rename(dsl_dir_t *dd, const char *newname)
1288 {
1289         struct renamearg ra;
1290         int err;
1291
1292         /* new parent should exist */
1293         err = dsl_dir_open(newname, FTAG, &ra.newparent, &ra.mynewname);
1294         if (err)
1295                 return (err);
1296
1297         /* can't rename to different pool */
1298         if (dd->dd_pool != ra.newparent->dd_pool) {
1299                 err = ENXIO;
1300                 goto out;
1301         }
1302
1303         /* new name should not already exist */
1304         if (ra.mynewname == NULL) {
1305                 err = EEXIST;
1306                 goto out;
1307         }
1308
1309         err = dsl_sync_task_do(dd->dd_pool,
1310             dsl_dir_rename_check, dsl_dir_rename_sync, dd, &ra, 3);
1311
1312 out:
1313         dsl_dir_close(ra.newparent, FTAG);
1314         return (err);
1315 }
1316
1317 int
1318 dsl_dir_transfer_possible(dsl_dir_t *sdd, dsl_dir_t *tdd, uint64_t space)
1319 {
1320         dsl_dir_t *ancestor;
1321         int64_t adelta;
1322         uint64_t avail;
1323
1324         ancestor = closest_common_ancestor(sdd, tdd);
1325         adelta = would_change(sdd, -space, ancestor);
1326         avail = dsl_dir_space_available(tdd, ancestor, adelta, FALSE);
1327         if (avail < space)
1328                 return (ENOSPC);
1329
1330         return (0);
1331 }