xref: /illumos-gate/usr/src/uts/common/fs/zfs/dsl_dataset.c (revision a194faf8907a6722dcf10ad16c6ca72c9b7bd0ba)
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 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include <sys/dmu_objset.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/dmu_traverse.h>
34 #include <sys/dmu_tx.h>
35 #include <sys/arc.h>
36 #include <sys/zio.h>
37 #include <sys/zap.h>
38 #include <sys/unique.h>
39 #include <sys/zfs_context.h>
40 #include <sys/zfs_ioctl.h>
41 #include <sys/spa.h>
42 #include <sys/sunddi.h>
43 
44 static dsl_checkfunc_t dsl_dataset_destroy_begin_check;
45 static dsl_syncfunc_t dsl_dataset_destroy_begin_sync;
46 static dsl_checkfunc_t dsl_dataset_rollback_check;
47 static dsl_syncfunc_t dsl_dataset_rollback_sync;
48 static dsl_syncfunc_t dsl_dataset_set_reservation_sync;
49 
50 #define	DS_REF_MAX	(1ULL << 62)
51 
52 #define	DSL_DEADLIST_BLOCKSIZE	SPA_MAXBLOCKSIZE
53 
54 /*
55  * We use weighted reference counts to express the various forms of exclusion
56  * between different open modes.  A STANDARD open is 1 point, an EXCLUSIVE open
57  * is DS_REF_MAX, and a PRIMARY open is little more than half of an EXCLUSIVE.
58  * This makes the exclusion logic simple: the total refcnt for all opens cannot
59  * exceed DS_REF_MAX.  For example, EXCLUSIVE opens are exclusive because their
60  * weight (DS_REF_MAX) consumes the entire refcnt space.  PRIMARY opens consume
61  * just over half of the refcnt space, so there can't be more than one, but it
62  * can peacefully coexist with any number of STANDARD opens.
63  */
64 static uint64_t ds_refcnt_weight[DS_MODE_LEVELS] = {
65 	0,			/* DS_MODE_NONE - invalid		*/
66 	1,			/* DS_MODE_STANDARD - unlimited number	*/
67 	(DS_REF_MAX >> 1) + 1,	/* DS_MODE_PRIMARY - only one of these	*/
68 	DS_REF_MAX		/* DS_MODE_EXCLUSIVE - no other opens	*/
69 };
70 
71 /*
72  * Figure out how much of this delta should be propogated to the dsl_dir
73  * layer.  If there's a refreservation, that space has already been
74  * partially accounted for in our ancestors.
75  */
76 static int64_t
77 parent_delta(dsl_dataset_t *ds, int64_t delta)
78 {
79 	uint64_t old_bytes, new_bytes;
80 
81 	if (ds->ds_reserved == 0)
82 		return (delta);
83 
84 	old_bytes = MAX(ds->ds_phys->ds_unique_bytes, ds->ds_reserved);
85 	new_bytes = MAX(ds->ds_phys->ds_unique_bytes + delta, ds->ds_reserved);
86 
87 	ASSERT3U(ABS((int64_t)(new_bytes - old_bytes)), <=, ABS(delta));
88 	return (new_bytes - old_bytes);
89 }
90 
91 void
92 dsl_dataset_block_born(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
93 {
94 	int used = bp_get_dasize(tx->tx_pool->dp_spa, bp);
95 	int compressed = BP_GET_PSIZE(bp);
96 	int uncompressed = BP_GET_UCSIZE(bp);
97 	int64_t delta;
98 
99 	dprintf_bp(bp, "born, ds=%p\n", ds);
100 
101 	ASSERT(dmu_tx_is_syncing(tx));
102 	/* It could have been compressed away to nothing */
103 	if (BP_IS_HOLE(bp))
104 		return;
105 	ASSERT(BP_GET_TYPE(bp) != DMU_OT_NONE);
106 	ASSERT3U(BP_GET_TYPE(bp), <, DMU_OT_NUMTYPES);
107 	if (ds == NULL) {
108 		/*
109 		 * Account for the meta-objset space in its placeholder
110 		 * dsl_dir.
111 		 */
112 		ASSERT3U(compressed, ==, uncompressed); /* it's all metadata */
113 		dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir,
114 		    used, compressed, uncompressed, tx);
115 		dsl_dir_dirty(tx->tx_pool->dp_mos_dir, tx);
116 		return;
117 	}
118 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
119 	mutex_enter(&ds->ds_lock);
120 	delta = parent_delta(ds, used);
121 	ds->ds_phys->ds_used_bytes += used;
122 	ds->ds_phys->ds_compressed_bytes += compressed;
123 	ds->ds_phys->ds_uncompressed_bytes += uncompressed;
124 	ds->ds_phys->ds_unique_bytes += used;
125 	mutex_exit(&ds->ds_lock);
126 	dsl_dir_diduse_space(ds->ds_dir, delta, compressed, uncompressed, tx);
127 }
128 
129 void
130 dsl_dataset_block_kill(dsl_dataset_t *ds, blkptr_t *bp, zio_t *pio,
131     dmu_tx_t *tx)
132 {
133 	int used = bp_get_dasize(tx->tx_pool->dp_spa, bp);
134 	int compressed = BP_GET_PSIZE(bp);
135 	int uncompressed = BP_GET_UCSIZE(bp);
136 
137 	ASSERT(dmu_tx_is_syncing(tx));
138 	/* No block pointer => nothing to free */
139 	if (BP_IS_HOLE(bp))
140 		return;
141 
142 	ASSERT(used > 0);
143 	if (ds == NULL) {
144 		int err;
145 		/*
146 		 * Account for the meta-objset space in its placeholder
147 		 * dataset.
148 		 */
149 		err = arc_free(pio, tx->tx_pool->dp_spa,
150 		    tx->tx_txg, bp, NULL, NULL, pio ? ARC_NOWAIT: ARC_WAIT);
151 		ASSERT(err == 0);
152 
153 		dsl_dir_diduse_space(tx->tx_pool->dp_mos_dir,
154 		    -used, -compressed, -uncompressed, tx);
155 		dsl_dir_dirty(tx->tx_pool->dp_mos_dir, tx);
156 		return;
157 	}
158 	ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool);
159 
160 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
161 
162 	if (bp->blk_birth > ds->ds_phys->ds_prev_snap_txg) {
163 		int err;
164 		int64_t delta;
165 
166 		dprintf_bp(bp, "freeing: %s", "");
167 		err = arc_free(pio, tx->tx_pool->dp_spa,
168 		    tx->tx_txg, bp, NULL, NULL, pio ? ARC_NOWAIT: ARC_WAIT);
169 		ASSERT(err == 0);
170 
171 		mutex_enter(&ds->ds_lock);
172 		ASSERT(ds->ds_phys->ds_unique_bytes >= used ||
173 		    !DS_UNIQUE_IS_ACCURATE(ds));
174 		delta = parent_delta(ds, -used);
175 		ds->ds_phys->ds_unique_bytes -= used;
176 		mutex_exit(&ds->ds_lock);
177 		dsl_dir_diduse_space(ds->ds_dir,
178 		    delta, -compressed, -uncompressed, tx);
179 	} else {
180 		dprintf_bp(bp, "putting on dead list: %s", "");
181 		VERIFY(0 == bplist_enqueue(&ds->ds_deadlist, bp, tx));
182 		/* if (bp->blk_birth > prev prev snap txg) prev unique += bs */
183 		if (ds->ds_phys->ds_prev_snap_obj != 0) {
184 			ASSERT3U(ds->ds_prev->ds_object, ==,
185 			    ds->ds_phys->ds_prev_snap_obj);
186 			ASSERT(ds->ds_prev->ds_phys->ds_num_children > 0);
187 			if (ds->ds_prev->ds_phys->ds_next_snap_obj ==
188 			    ds->ds_object && bp->blk_birth >
189 			    ds->ds_prev->ds_phys->ds_prev_snap_txg) {
190 				dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
191 				mutex_enter(&ds->ds_prev->ds_lock);
192 				ds->ds_prev->ds_phys->ds_unique_bytes +=
193 				    used;
194 				mutex_exit(&ds->ds_prev->ds_lock);
195 			}
196 		}
197 	}
198 	mutex_enter(&ds->ds_lock);
199 	ASSERT3U(ds->ds_phys->ds_used_bytes, >=, used);
200 	ds->ds_phys->ds_used_bytes -= used;
201 	ASSERT3U(ds->ds_phys->ds_compressed_bytes, >=, compressed);
202 	ds->ds_phys->ds_compressed_bytes -= compressed;
203 	ASSERT3U(ds->ds_phys->ds_uncompressed_bytes, >=, uncompressed);
204 	ds->ds_phys->ds_uncompressed_bytes -= uncompressed;
205 	mutex_exit(&ds->ds_lock);
206 }
207 
208 uint64_t
209 dsl_dataset_prev_snap_txg(dsl_dataset_t *ds)
210 {
211 	uint64_t trysnap = 0;
212 
213 	if (ds == NULL)
214 		return (0);
215 	/*
216 	 * The snapshot creation could fail, but that would cause an
217 	 * incorrect FALSE return, which would only result in an
218 	 * overestimation of the amount of space that an operation would
219 	 * consume, which is OK.
220 	 *
221 	 * There's also a small window where we could miss a pending
222 	 * snapshot, because we could set the sync task in the quiescing
223 	 * phase.  So this should only be used as a guess.
224 	 */
225 	if (ds->ds_trysnap_txg >
226 	    spa_last_synced_txg(ds->ds_dir->dd_pool->dp_spa))
227 		trysnap = ds->ds_trysnap_txg;
228 	return (MAX(ds->ds_phys->ds_prev_snap_txg, trysnap));
229 }
230 
231 int
232 dsl_dataset_block_freeable(dsl_dataset_t *ds, uint64_t blk_birth)
233 {
234 	return (blk_birth > dsl_dataset_prev_snap_txg(ds));
235 }
236 
237 /* ARGSUSED */
238 static void
239 dsl_dataset_evict(dmu_buf_t *db, void *dsv)
240 {
241 	dsl_dataset_t *ds = dsv;
242 
243 	/* open_refcount == DS_REF_MAX when deleting */
244 	ASSERT(ds->ds_open_refcount == 0 ||
245 	    ds->ds_open_refcount == DS_REF_MAX);
246 
247 	dprintf_ds(ds, "evicting %s\n", "");
248 
249 	unique_remove(ds->ds_fsid_guid);
250 
251 	if (ds->ds_user_ptr != NULL)
252 		ds->ds_user_evict_func(ds, ds->ds_user_ptr);
253 
254 	if (ds->ds_prev) {
255 		dsl_dataset_close(ds->ds_prev, DS_MODE_NONE, ds);
256 		ds->ds_prev = NULL;
257 	}
258 
259 	bplist_close(&ds->ds_deadlist);
260 	dsl_dir_close(ds->ds_dir, ds);
261 
262 	ASSERT(!list_link_active(&ds->ds_synced_link));
263 
264 	mutex_destroy(&ds->ds_lock);
265 	mutex_destroy(&ds->ds_opening_lock);
266 	mutex_destroy(&ds->ds_deadlist.bpl_lock);
267 
268 	kmem_free(ds, sizeof (dsl_dataset_t));
269 }
270 
271 static int
272 dsl_dataset_get_snapname(dsl_dataset_t *ds)
273 {
274 	dsl_dataset_phys_t *headphys;
275 	int err;
276 	dmu_buf_t *headdbuf;
277 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
278 	objset_t *mos = dp->dp_meta_objset;
279 
280 	if (ds->ds_snapname[0])
281 		return (0);
282 	if (ds->ds_phys->ds_next_snap_obj == 0)
283 		return (0);
284 
285 	err = dmu_bonus_hold(mos, ds->ds_dir->dd_phys->dd_head_dataset_obj,
286 	    FTAG, &headdbuf);
287 	if (err)
288 		return (err);
289 	headphys = headdbuf->db_data;
290 	err = zap_value_search(dp->dp_meta_objset,
291 	    headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
292 	dmu_buf_rele(headdbuf, FTAG);
293 	return (err);
294 }
295 
296 int
297 dsl_dataset_open_obj(dsl_pool_t *dp, uint64_t dsobj, const char *snapname,
298     int mode, void *tag, dsl_dataset_t **dsp)
299 {
300 	uint64_t weight = ds_refcnt_weight[DS_MODE_LEVEL(mode)];
301 	objset_t *mos = dp->dp_meta_objset;
302 	dmu_buf_t *dbuf;
303 	dsl_dataset_t *ds;
304 	int err;
305 
306 	ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock) ||
307 	    dsl_pool_sync_context(dp));
308 
309 	err = dmu_bonus_hold(mos, dsobj, tag, &dbuf);
310 	if (err)
311 		return (err);
312 	ds = dmu_buf_get_user(dbuf);
313 	if (ds == NULL) {
314 		dsl_dataset_t *winner;
315 
316 		ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP);
317 		ds->ds_dbuf = dbuf;
318 		ds->ds_object = dsobj;
319 		ds->ds_phys = dbuf->db_data;
320 
321 		mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
322 		mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
323 		mutex_init(&ds->ds_deadlist.bpl_lock, NULL, MUTEX_DEFAULT,
324 		    NULL);
325 
326 		err = bplist_open(&ds->ds_deadlist,
327 		    mos, ds->ds_phys->ds_deadlist_obj);
328 		if (err == 0) {
329 			err = dsl_dir_open_obj(dp,
330 			    ds->ds_phys->ds_dir_obj, NULL, ds, &ds->ds_dir);
331 		}
332 		if (err) {
333 			/*
334 			 * we don't really need to close the blist if we
335 			 * just opened it.
336 			 */
337 			mutex_destroy(&ds->ds_lock);
338 			mutex_destroy(&ds->ds_opening_lock);
339 			mutex_destroy(&ds->ds_deadlist.bpl_lock);
340 			kmem_free(ds, sizeof (dsl_dataset_t));
341 			dmu_buf_rele(dbuf, tag);
342 			return (err);
343 		}
344 
345 		if (ds->ds_dir->dd_phys->dd_head_dataset_obj == dsobj) {
346 			ds->ds_snapname[0] = '\0';
347 			if (ds->ds_phys->ds_prev_snap_obj) {
348 				err = dsl_dataset_open_obj(dp,
349 				    ds->ds_phys->ds_prev_snap_obj, NULL,
350 				    DS_MODE_NONE, ds, &ds->ds_prev);
351 			}
352 		} else {
353 			if (snapname) {
354 #ifdef ZFS_DEBUG
355 				dsl_dataset_phys_t *headphys;
356 				dmu_buf_t *headdbuf;
357 				err = dmu_bonus_hold(mos,
358 				    ds->ds_dir->dd_phys->dd_head_dataset_obj,
359 				    FTAG, &headdbuf);
360 				if (err == 0) {
361 					headphys = headdbuf->db_data;
362 					uint64_t foundobj;
363 					err = zap_lookup(dp->dp_meta_objset,
364 					    headphys->ds_snapnames_zapobj,
365 					    snapname, sizeof (foundobj), 1,
366 					    &foundobj);
367 					ASSERT3U(foundobj, ==, dsobj);
368 					dmu_buf_rele(headdbuf, FTAG);
369 				}
370 #endif
371 				(void) strcat(ds->ds_snapname, snapname);
372 			} else if (zfs_flags & ZFS_DEBUG_SNAPNAMES) {
373 				err = dsl_dataset_get_snapname(ds);
374 			}
375 		}
376 
377 		if (!dsl_dataset_is_snapshot(ds)) {
378 			boolean_t need_lock =
379 			    !RW_LOCK_HELD(&dp->dp_config_rwlock);
380 
381 			if (need_lock)
382 				rw_enter(&dp->dp_config_rwlock, RW_READER);
383 
384 			err = dsl_prop_get_ds_locked(ds->ds_dir,
385 			    "refreservation", sizeof (uint64_t), 1,
386 			    &ds->ds_reserved, NULL);
387 			if (err == 0) {
388 				err = dsl_prop_get_ds_locked(ds->ds_dir,
389 				    "refquota", sizeof (uint64_t), 1,
390 				    &ds->ds_quota, NULL);
391 			}
392 
393 			if (need_lock)
394 				rw_exit(&dp->dp_config_rwlock);
395 		} else {
396 			ds->ds_reserved = ds->ds_quota = 0;
397 		}
398 
399 		if (err == 0) {
400 			winner = dmu_buf_set_user_ie(dbuf, ds, &ds->ds_phys,
401 			    dsl_dataset_evict);
402 		}
403 		if (err || winner) {
404 			bplist_close(&ds->ds_deadlist);
405 			if (ds->ds_prev) {
406 				dsl_dataset_close(ds->ds_prev,
407 				    DS_MODE_NONE, ds);
408 			}
409 			dsl_dir_close(ds->ds_dir, ds);
410 			mutex_destroy(&ds->ds_lock);
411 			mutex_destroy(&ds->ds_opening_lock);
412 			mutex_destroy(&ds->ds_deadlist.bpl_lock);
413 			kmem_free(ds, sizeof (dsl_dataset_t));
414 			if (err) {
415 				dmu_buf_rele(dbuf, tag);
416 				return (err);
417 			}
418 			ds = winner;
419 		} else {
420 			ds->ds_fsid_guid =
421 			    unique_insert(ds->ds_phys->ds_fsid_guid);
422 		}
423 	}
424 	ASSERT3P(ds->ds_dbuf, ==, dbuf);
425 	ASSERT3P(ds->ds_phys, ==, dbuf->db_data);
426 
427 	mutex_enter(&ds->ds_lock);
428 	if ((DS_MODE_LEVEL(mode) == DS_MODE_PRIMARY &&
429 	    (ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT) &&
430 	    !DS_MODE_IS_INCONSISTENT(mode)) ||
431 	    (ds->ds_open_refcount + weight > DS_REF_MAX)) {
432 		mutex_exit(&ds->ds_lock);
433 		dsl_dataset_close(ds, DS_MODE_NONE, tag);
434 		return (EBUSY);
435 	}
436 	ds->ds_open_refcount += weight;
437 	mutex_exit(&ds->ds_lock);
438 
439 	*dsp = ds;
440 	return (0);
441 }
442 
443 int
444 dsl_dataset_open_spa(spa_t *spa, const char *name, int mode,
445     void *tag, dsl_dataset_t **dsp)
446 {
447 	dsl_dir_t *dd;
448 	dsl_pool_t *dp;
449 	const char *tail;
450 	uint64_t obj;
451 	dsl_dataset_t *ds = NULL;
452 	int err = 0;
453 
454 	err = dsl_dir_open_spa(spa, name, FTAG, &dd, &tail);
455 	if (err)
456 		return (err);
457 
458 	dp = dd->dd_pool;
459 	obj = dd->dd_phys->dd_head_dataset_obj;
460 	rw_enter(&dp->dp_config_rwlock, RW_READER);
461 	if (obj == 0) {
462 		/* A dataset with no associated objset */
463 		err = ENOENT;
464 		goto out;
465 	}
466 
467 	if (tail != NULL) {
468 		objset_t *mos = dp->dp_meta_objset;
469 
470 		err = dsl_dataset_open_obj(dp, obj, NULL,
471 		    DS_MODE_NONE, tag, &ds);
472 		if (err)
473 			goto out;
474 		obj = ds->ds_phys->ds_snapnames_zapobj;
475 		dsl_dataset_close(ds, DS_MODE_NONE, tag);
476 		ds = NULL;
477 
478 		if (tail[0] != '@') {
479 			err = ENOENT;
480 			goto out;
481 		}
482 		tail++;
483 
484 		/* Look for a snapshot */
485 		if (!DS_MODE_IS_READONLY(mode)) {
486 			err = EROFS;
487 			goto out;
488 		}
489 		dprintf("looking for snapshot '%s'\n", tail);
490 		err = zap_lookup(mos, obj, tail, 8, 1, &obj);
491 		if (err)
492 			goto out;
493 	}
494 	err = dsl_dataset_open_obj(dp, obj, tail, mode, tag, &ds);
495 
496 out:
497 	rw_exit(&dp->dp_config_rwlock);
498 	dsl_dir_close(dd, FTAG);
499 
500 	ASSERT3U((err == 0), ==, (ds != NULL));
501 	/* ASSERT(ds == NULL || strcmp(name, ds->ds_name) == 0); */
502 
503 	*dsp = ds;
504 	return (err);
505 }
506 
507 int
508 dsl_dataset_open(const char *name, int mode, void *tag, dsl_dataset_t **dsp)
509 {
510 	return (dsl_dataset_open_spa(NULL, name, mode, tag, dsp));
511 }
512 
513 void
514 dsl_dataset_name(dsl_dataset_t *ds, char *name)
515 {
516 	if (ds == NULL) {
517 		(void) strcpy(name, "mos");
518 	} else {
519 		dsl_dir_name(ds->ds_dir, name);
520 		VERIFY(0 == dsl_dataset_get_snapname(ds));
521 		if (ds->ds_snapname[0]) {
522 			(void) strcat(name, "@");
523 			if (!MUTEX_HELD(&ds->ds_lock)) {
524 				/*
525 				 * We use a "recursive" mutex so that we
526 				 * can call dprintf_ds() with ds_lock held.
527 				 */
528 				mutex_enter(&ds->ds_lock);
529 				(void) strcat(name, ds->ds_snapname);
530 				mutex_exit(&ds->ds_lock);
531 			} else {
532 				(void) strcat(name, ds->ds_snapname);
533 			}
534 		}
535 	}
536 }
537 
538 static int
539 dsl_dataset_namelen(dsl_dataset_t *ds)
540 {
541 	int result;
542 
543 	if (ds == NULL) {
544 		result = 3;	/* "mos" */
545 	} else {
546 		result = dsl_dir_namelen(ds->ds_dir);
547 		VERIFY(0 == dsl_dataset_get_snapname(ds));
548 		if (ds->ds_snapname[0]) {
549 			++result;	/* adding one for the @-sign */
550 			if (!MUTEX_HELD(&ds->ds_lock)) {
551 				/* see dsl_datset_name */
552 				mutex_enter(&ds->ds_lock);
553 				result += strlen(ds->ds_snapname);
554 				mutex_exit(&ds->ds_lock);
555 			} else {
556 				result += strlen(ds->ds_snapname);
557 			}
558 		}
559 	}
560 
561 	return (result);
562 }
563 
564 void
565 dsl_dataset_close(dsl_dataset_t *ds, int mode, void *tag)
566 {
567 	uint64_t weight = ds_refcnt_weight[DS_MODE_LEVEL(mode)];
568 	mutex_enter(&ds->ds_lock);
569 	ASSERT3U(ds->ds_open_refcount, >=, weight);
570 	ds->ds_open_refcount -= weight;
571 	dprintf_ds(ds, "closing mode %u refcount now 0x%llx\n",
572 	    mode, ds->ds_open_refcount);
573 	mutex_exit(&ds->ds_lock);
574 
575 	dmu_buf_rele(ds->ds_dbuf, tag);
576 }
577 
578 void
579 dsl_dataset_downgrade(dsl_dataset_t *ds, int oldmode, int newmode)
580 {
581 	uint64_t oldweight = ds_refcnt_weight[DS_MODE_LEVEL(oldmode)];
582 	uint64_t newweight = ds_refcnt_weight[DS_MODE_LEVEL(newmode)];
583 	mutex_enter(&ds->ds_lock);
584 	ASSERT3U(ds->ds_open_refcount, >=, oldweight);
585 	ASSERT3U(oldweight, >=, newweight);
586 	ds->ds_open_refcount -= oldweight;
587 	ds->ds_open_refcount += newweight;
588 	mutex_exit(&ds->ds_lock);
589 }
590 
591 boolean_t
592 dsl_dataset_tryupgrade(dsl_dataset_t *ds, int oldmode, int newmode)
593 {
594 	boolean_t rv;
595 	uint64_t oldweight = ds_refcnt_weight[DS_MODE_LEVEL(oldmode)];
596 	uint64_t newweight = ds_refcnt_weight[DS_MODE_LEVEL(newmode)];
597 	mutex_enter(&ds->ds_lock);
598 	ASSERT3U(ds->ds_open_refcount, >=, oldweight);
599 	ASSERT3U(newweight, >=, oldweight);
600 	if (ds->ds_open_refcount - oldweight + newweight > DS_REF_MAX) {
601 		rv = B_FALSE;
602 	} else {
603 		ds->ds_open_refcount -= oldweight;
604 		ds->ds_open_refcount += newweight;
605 		rv = B_TRUE;
606 	}
607 	mutex_exit(&ds->ds_lock);
608 	return (rv);
609 }
610 
611 void
612 dsl_dataset_create_root(dsl_pool_t *dp, uint64_t *ddobjp, dmu_tx_t *tx)
613 {
614 	objset_t *mos = dp->dp_meta_objset;
615 	dmu_buf_t *dbuf;
616 	dsl_dataset_phys_t *dsphys;
617 	dsl_dataset_t *ds;
618 	uint64_t dsobj;
619 	dsl_dir_t *dd;
620 
621 	dsl_dir_create_root(mos, ddobjp, tx);
622 	VERIFY(0 == dsl_dir_open_obj(dp, *ddobjp, NULL, FTAG, &dd));
623 
624 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
625 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
626 	VERIFY(0 == dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
627 	dmu_buf_will_dirty(dbuf, tx);
628 	dsphys = dbuf->db_data;
629 	dsphys->ds_dir_obj = dd->dd_object;
630 	dsphys->ds_fsid_guid = unique_create();
631 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
632 	    sizeof (dsphys->ds_guid));
633 	dsphys->ds_snapnames_zapobj =
634 	    zap_create(mos, DMU_OT_DSL_DS_SNAP_MAP, DMU_OT_NONE, 0, tx);
635 	dsphys->ds_creation_time = gethrestime_sec();
636 	dsphys->ds_creation_txg = tx->tx_txg;
637 	dsphys->ds_deadlist_obj =
638 	    bplist_create(mos, DSL_DEADLIST_BLOCKSIZE, tx);
639 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
640 		dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
641 	dmu_buf_rele(dbuf, FTAG);
642 
643 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
644 	dd->dd_phys->dd_head_dataset_obj = dsobj;
645 	dsl_dir_close(dd, FTAG);
646 
647 	VERIFY(0 ==
648 	    dsl_dataset_open_obj(dp, dsobj, NULL, DS_MODE_NONE, FTAG, &ds));
649 	(void) dmu_objset_create_impl(dp->dp_spa, ds,
650 	    &ds->ds_phys->ds_bp, DMU_OST_ZFS, tx);
651 	dsl_dataset_close(ds, DS_MODE_NONE, FTAG);
652 }
653 
654 uint64_t
655 dsl_dataset_create_sync_impl(dsl_dir_t *dd, dsl_dataset_t *origin, dmu_tx_t *tx)
656 {
657 	dsl_pool_t *dp = dd->dd_pool;
658 	dmu_buf_t *dbuf;
659 	dsl_dataset_phys_t *dsphys;
660 	uint64_t dsobj;
661 	objset_t *mos = dp->dp_meta_objset;
662 
663 	ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
664 	ASSERT(origin == NULL || origin->ds_phys->ds_num_children > 0);
665 	ASSERT(dmu_tx_is_syncing(tx));
666 	ASSERT(dd->dd_phys->dd_head_dataset_obj == 0);
667 
668 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
669 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
670 	VERIFY(0 == dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
671 	dmu_buf_will_dirty(dbuf, tx);
672 	dsphys = dbuf->db_data;
673 	dsphys->ds_dir_obj = dd->dd_object;
674 	dsphys->ds_fsid_guid = unique_create();
675 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
676 	    sizeof (dsphys->ds_guid));
677 	dsphys->ds_snapnames_zapobj =
678 	    zap_create(mos, DMU_OT_DSL_DS_SNAP_MAP, DMU_OT_NONE, 0, tx);
679 	dsphys->ds_creation_time = gethrestime_sec();
680 	dsphys->ds_creation_txg = tx->tx_txg;
681 	dsphys->ds_deadlist_obj =
682 	    bplist_create(mos, DSL_DEADLIST_BLOCKSIZE, tx);
683 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
684 		dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
685 
686 	if (origin) {
687 		dsphys->ds_prev_snap_obj = origin->ds_object;
688 		dsphys->ds_prev_snap_txg =
689 		    origin->ds_phys->ds_creation_txg;
690 		dsphys->ds_used_bytes =
691 		    origin->ds_phys->ds_used_bytes;
692 		dsphys->ds_compressed_bytes =
693 		    origin->ds_phys->ds_compressed_bytes;
694 		dsphys->ds_uncompressed_bytes =
695 		    origin->ds_phys->ds_uncompressed_bytes;
696 		dsphys->ds_bp = origin->ds_phys->ds_bp;
697 
698 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
699 		origin->ds_phys->ds_num_children++;
700 
701 		dmu_buf_will_dirty(dd->dd_dbuf, tx);
702 		dd->dd_phys->dd_origin_obj = origin->ds_object;
703 	}
704 	dmu_buf_rele(dbuf, FTAG);
705 
706 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
707 	dd->dd_phys->dd_head_dataset_obj = dsobj;
708 
709 	return (dsobj);
710 }
711 
712 uint64_t
713 dsl_dataset_create_sync(dsl_dir_t *pdd,
714     const char *lastname, dsl_dataset_t *origin, cred_t *cr, dmu_tx_t *tx)
715 {
716 	dsl_pool_t *dp = pdd->dd_pool;
717 	uint64_t dsobj, ddobj;
718 	dsl_dir_t *dd;
719 
720 	ASSERT(lastname[0] != '@');
721 
722 	ddobj = dsl_dir_create_sync(pdd, lastname, tx);
723 	VERIFY(0 == dsl_dir_open_obj(dp, ddobj, lastname, FTAG, &dd));
724 
725 	dsobj = dsl_dataset_create_sync_impl(dd, origin, tx);
726 
727 	dsl_deleg_set_create_perms(dd, tx, cr);
728 
729 	dsl_dir_close(dd, FTAG);
730 
731 	return (dsobj);
732 }
733 
734 struct destroyarg {
735 	dsl_sync_task_group_t *dstg;
736 	char *snapname;
737 	char *failed;
738 };
739 
740 static int
741 dsl_snapshot_destroy_one(char *name, void *arg)
742 {
743 	struct destroyarg *da = arg;
744 	dsl_dataset_t *ds;
745 	char *cp;
746 	int err;
747 
748 	(void) strcat(name, "@");
749 	(void) strcat(name, da->snapname);
750 	err = dsl_dataset_open(name,
751 	    DS_MODE_EXCLUSIVE | DS_MODE_READONLY | DS_MODE_INCONSISTENT,
752 	    da->dstg, &ds);
753 	cp = strchr(name, '@');
754 	*cp = '\0';
755 	if (err == ENOENT)
756 		return (0);
757 	if (err) {
758 		(void) strcpy(da->failed, name);
759 		return (err);
760 	}
761 
762 	dsl_sync_task_create(da->dstg, dsl_dataset_destroy_check,
763 	    dsl_dataset_destroy_sync, ds, da->dstg, 0);
764 	return (0);
765 }
766 
767 /*
768  * Destroy 'snapname' in all descendants of 'fsname'.
769  */
770 #pragma weak dmu_snapshots_destroy = dsl_snapshots_destroy
771 int
772 dsl_snapshots_destroy(char *fsname, char *snapname)
773 {
774 	int err;
775 	struct destroyarg da;
776 	dsl_sync_task_t *dst;
777 	spa_t *spa;
778 
779 	err = spa_open(fsname, &spa, FTAG);
780 	if (err)
781 		return (err);
782 	da.dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
783 	da.snapname = snapname;
784 	da.failed = fsname;
785 
786 	err = dmu_objset_find(fsname,
787 	    dsl_snapshot_destroy_one, &da, DS_FIND_CHILDREN);
788 
789 	if (err == 0)
790 		err = dsl_sync_task_group_wait(da.dstg);
791 
792 	for (dst = list_head(&da.dstg->dstg_tasks); dst;
793 	    dst = list_next(&da.dstg->dstg_tasks, dst)) {
794 		dsl_dataset_t *ds = dst->dst_arg1;
795 		if (dst->dst_err) {
796 			dsl_dataset_name(ds, fsname);
797 			*strchr(fsname, '@') = '\0';
798 		}
799 		/*
800 		 * If it was successful, destroy_sync would have
801 		 * closed the ds
802 		 */
803 		if (err)
804 			dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, da.dstg);
805 	}
806 
807 	dsl_sync_task_group_destroy(da.dstg);
808 	spa_close(spa, FTAG);
809 	return (err);
810 }
811 
812 /*
813  * ds must be opened EXCLUSIVE or PRIMARY.  on return (whether
814  * successful or not), ds will be closed and caller can no longer
815  * dereference it.
816  */
817 int
818 dsl_dataset_destroy(dsl_dataset_t *ds, void *tag)
819 {
820 	int err;
821 	dsl_sync_task_group_t *dstg;
822 	objset_t *os;
823 	dsl_dir_t *dd;
824 	uint64_t obj;
825 
826 	if (ds->ds_open_refcount != DS_REF_MAX) {
827 		if (dsl_dataset_tryupgrade(ds, DS_MODE_PRIMARY,
828 		    DS_MODE_EXCLUSIVE) == 0) {
829 			dsl_dataset_close(ds, DS_MODE_PRIMARY, tag);
830 			return (EBUSY);
831 		}
832 	}
833 
834 	if (dsl_dataset_is_snapshot(ds)) {
835 		/* Destroying a snapshot is simpler */
836 		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
837 		    dsl_dataset_destroy_check, dsl_dataset_destroy_sync,
838 		    ds, tag, 0);
839 		goto out;
840 	}
841 
842 	dd = ds->ds_dir;
843 
844 	/*
845 	 * Check for errors and mark this ds as inconsistent, in
846 	 * case we crash while freeing the objects.
847 	 */
848 	err = dsl_sync_task_do(dd->dd_pool, dsl_dataset_destroy_begin_check,
849 	    dsl_dataset_destroy_begin_sync, ds, NULL, 0);
850 	if (err)
851 		goto out;
852 
853 	err = dmu_objset_open_ds(ds, DMU_OST_ANY, &os);
854 	if (err)
855 		goto out;
856 
857 	/*
858 	 * remove the objects in open context, so that we won't
859 	 * have too much to do in syncing context.
860 	 */
861 	for (obj = 0; err == 0; err = dmu_object_next(os, &obj, FALSE,
862 	    ds->ds_phys->ds_prev_snap_txg)) {
863 		dmu_tx_t *tx = dmu_tx_create(os);
864 		dmu_tx_hold_free(tx, obj, 0, DMU_OBJECT_END);
865 		dmu_tx_hold_bonus(tx, obj);
866 		err = dmu_tx_assign(tx, TXG_WAIT);
867 		if (err) {
868 			/*
869 			 * Perhaps there is not enough disk
870 			 * space.  Just deal with it from
871 			 * dsl_dataset_destroy_sync().
872 			 */
873 			dmu_tx_abort(tx);
874 			continue;
875 		}
876 		VERIFY(0 == dmu_object_free(os, obj, tx));
877 		dmu_tx_commit(tx);
878 	}
879 	/* Make sure it's not dirty before we finish destroying it. */
880 	txg_wait_synced(dd->dd_pool, 0);
881 
882 	dmu_objset_close(os);
883 	if (err != ESRCH)
884 		goto out;
885 
886 	if (ds->ds_user_ptr) {
887 		ds->ds_user_evict_func(ds, ds->ds_user_ptr);
888 		ds->ds_user_ptr = NULL;
889 	}
890 
891 	rw_enter(&dd->dd_pool->dp_config_rwlock, RW_READER);
892 	err = dsl_dir_open_obj(dd->dd_pool, dd->dd_object, NULL, FTAG, &dd);
893 	rw_exit(&dd->dd_pool->dp_config_rwlock);
894 
895 	if (err)
896 		goto out;
897 
898 	/*
899 	 * Blow away the dsl_dir + head dataset.
900 	 */
901 	dstg = dsl_sync_task_group_create(ds->ds_dir->dd_pool);
902 	dsl_sync_task_create(dstg, dsl_dataset_destroy_check,
903 	    dsl_dataset_destroy_sync, ds, tag, 0);
904 	dsl_sync_task_create(dstg, dsl_dir_destroy_check,
905 	    dsl_dir_destroy_sync, dd, FTAG, 0);
906 	err = dsl_sync_task_group_wait(dstg);
907 	dsl_sync_task_group_destroy(dstg);
908 	/* if it is successful, *destroy_sync will close the ds+dd */
909 	if (err)
910 		dsl_dir_close(dd, FTAG);
911 out:
912 	if (err)
913 		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, tag);
914 	return (err);
915 }
916 
917 int
918 dsl_dataset_rollback(dsl_dataset_t *ds, dmu_objset_type_t ost)
919 {
920 	ASSERT3U(ds->ds_open_refcount, ==, DS_REF_MAX);
921 
922 	return (dsl_sync_task_do(ds->ds_dir->dd_pool,
923 	    dsl_dataset_rollback_check, dsl_dataset_rollback_sync,
924 	    ds, &ost, 0));
925 }
926 
927 void *
928 dsl_dataset_set_user_ptr(dsl_dataset_t *ds,
929     void *p, dsl_dataset_evict_func_t func)
930 {
931 	void *old;
932 
933 	mutex_enter(&ds->ds_lock);
934 	old = ds->ds_user_ptr;
935 	if (old == NULL) {
936 		ds->ds_user_ptr = p;
937 		ds->ds_user_evict_func = func;
938 	}
939 	mutex_exit(&ds->ds_lock);
940 	return (old);
941 }
942 
943 void *
944 dsl_dataset_get_user_ptr(dsl_dataset_t *ds)
945 {
946 	return (ds->ds_user_ptr);
947 }
948 
949 
950 blkptr_t *
951 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
952 {
953 	return (&ds->ds_phys->ds_bp);
954 }
955 
956 void
957 dsl_dataset_set_blkptr(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
958 {
959 	ASSERT(dmu_tx_is_syncing(tx));
960 	/* If it's the meta-objset, set dp_meta_rootbp */
961 	if (ds == NULL) {
962 		tx->tx_pool->dp_meta_rootbp = *bp;
963 	} else {
964 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
965 		ds->ds_phys->ds_bp = *bp;
966 	}
967 }
968 
969 spa_t *
970 dsl_dataset_get_spa(dsl_dataset_t *ds)
971 {
972 	return (ds->ds_dir->dd_pool->dp_spa);
973 }
974 
975 void
976 dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
977 {
978 	dsl_pool_t *dp;
979 
980 	if (ds == NULL) /* this is the meta-objset */
981 		return;
982 
983 	ASSERT(ds->ds_user_ptr != NULL);
984 
985 	if (ds->ds_phys->ds_next_snap_obj != 0)
986 		panic("dirtying snapshot!");
987 
988 	dp = ds->ds_dir->dd_pool;
989 
990 	if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg) == 0) {
991 		/* up the hold count until we can be written out */
992 		dmu_buf_add_ref(ds->ds_dbuf, ds);
993 	}
994 }
995 
996 /*
997  * The unique space in the head dataset can be calculated by subtracting
998  * the space used in the most recent snapshot, that is still being used
999  * in this file system, from the space currently in use.  To figure out
1000  * the space in the most recent snapshot still in use, we need to take
1001  * the total space used in the snapshot and subtract out the space that
1002  * has been freed up since the snapshot was taken.
1003  */
1004 static void
1005 dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
1006 {
1007 	uint64_t mrs_used;
1008 	uint64_t dlused, dlcomp, dluncomp;
1009 
1010 	ASSERT(ds->ds_object == ds->ds_dir->dd_phys->dd_head_dataset_obj);
1011 
1012 	if (ds->ds_phys->ds_prev_snap_obj != 0)
1013 		mrs_used = ds->ds_prev->ds_phys->ds_used_bytes;
1014 	else
1015 		mrs_used = 0;
1016 
1017 	VERIFY(0 == bplist_space(&ds->ds_deadlist, &dlused, &dlcomp,
1018 	    &dluncomp));
1019 
1020 	ASSERT3U(dlused, <=, mrs_used);
1021 	ds->ds_phys->ds_unique_bytes =
1022 	    ds->ds_phys->ds_used_bytes - (mrs_used - dlused);
1023 
1024 	if (!DS_UNIQUE_IS_ACCURATE(ds) &&
1025 	    spa_version(ds->ds_dir->dd_pool->dp_spa) >=
1026 	    SPA_VERSION_UNIQUE_ACCURATE)
1027 		ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1028 }
1029 
1030 static uint64_t
1031 dsl_dataset_unique(dsl_dataset_t *ds)
1032 {
1033 	if (!DS_UNIQUE_IS_ACCURATE(ds) && !dsl_dataset_is_snapshot(ds))
1034 		dsl_dataset_recalc_head_uniq(ds);
1035 
1036 	return (ds->ds_phys->ds_unique_bytes);
1037 }
1038 
1039 struct killarg {
1040 	int64_t *usedp;
1041 	int64_t *compressedp;
1042 	int64_t *uncompressedp;
1043 	zio_t *zio;
1044 	dmu_tx_t *tx;
1045 };
1046 
1047 static int
1048 kill_blkptr(traverse_blk_cache_t *bc, spa_t *spa, void *arg)
1049 {
1050 	struct killarg *ka = arg;
1051 	blkptr_t *bp = &bc->bc_blkptr;
1052 
1053 	ASSERT3U(bc->bc_errno, ==, 0);
1054 
1055 	/*
1056 	 * Since this callback is not called concurrently, no lock is
1057 	 * needed on the accounting values.
1058 	 */
1059 	*ka->usedp += bp_get_dasize(spa, bp);
1060 	*ka->compressedp += BP_GET_PSIZE(bp);
1061 	*ka->uncompressedp += BP_GET_UCSIZE(bp);
1062 	/* XXX check for EIO? */
1063 	(void) arc_free(ka->zio, spa, ka->tx->tx_txg, bp, NULL, NULL,
1064 	    ARC_NOWAIT);
1065 	return (0);
1066 }
1067 
1068 /* ARGSUSED */
1069 static int
1070 dsl_dataset_rollback_check(void *arg1, void *arg2, dmu_tx_t *tx)
1071 {
1072 	dsl_dataset_t *ds = arg1;
1073 	dmu_objset_type_t *ost = arg2;
1074 
1075 	/*
1076 	 * We can only roll back to emptyness if it is a ZPL objset.
1077 	 */
1078 	if (*ost != DMU_OST_ZFS && ds->ds_phys->ds_prev_snap_txg == 0)
1079 		return (EINVAL);
1080 
1081 	/*
1082 	 * This must not be a snapshot.
1083 	 */
1084 	if (ds->ds_phys->ds_next_snap_obj != 0)
1085 		return (EINVAL);
1086 
1087 	/*
1088 	 * If we made changes this txg, traverse_dsl_dataset won't find
1089 	 * them.  Try again.
1090 	 */
1091 	if (ds->ds_phys->ds_bp.blk_birth >= tx->tx_txg)
1092 		return (EAGAIN);
1093 
1094 	return (0);
1095 }
1096 
1097 /* ARGSUSED */
1098 static void
1099 dsl_dataset_rollback_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1100 {
1101 	dsl_dataset_t *ds = arg1;
1102 	dmu_objset_type_t *ost = arg2;
1103 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1104 
1105 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1106 
1107 	/*
1108 	 * Before the roll back destroy the zil.
1109 	 */
1110 	if (ds->ds_user_ptr != NULL) {
1111 		zil_rollback_destroy(
1112 		    ((objset_impl_t *)ds->ds_user_ptr)->os_zil, tx);
1113 
1114 		/*
1115 		 * We need to make sure that the objset_impl_t is reopened after
1116 		 * we do the rollback, otherwise it will have the wrong
1117 		 * objset_phys_t.  Normally this would happen when this
1118 		 * DS_MODE_EXCLUSIVE dataset-open is closed, thus causing the
1119 		 * dataset to be immediately evicted.  But when doing "zfs recv
1120 		 * -F", we reopen the objset before that, so that there is no
1121 		 * window where the dataset is closed and inconsistent.
1122 		 */
1123 		ds->ds_user_evict_func(ds, ds->ds_user_ptr);
1124 		ds->ds_user_ptr = NULL;
1125 	}
1126 
1127 	/* Zero out the deadlist. */
1128 	bplist_close(&ds->ds_deadlist);
1129 	bplist_destroy(mos, ds->ds_phys->ds_deadlist_obj, tx);
1130 	ds->ds_phys->ds_deadlist_obj =
1131 	    bplist_create(mos, DSL_DEADLIST_BLOCKSIZE, tx);
1132 	VERIFY(0 == bplist_open(&ds->ds_deadlist, mos,
1133 	    ds->ds_phys->ds_deadlist_obj));
1134 
1135 	{
1136 		/* Free blkptrs that we gave birth to */
1137 		zio_t *zio;
1138 		int64_t used = 0, compressed = 0, uncompressed = 0;
1139 		struct killarg ka;
1140 		int64_t delta;
1141 
1142 		zio = zio_root(tx->tx_pool->dp_spa, NULL, NULL,
1143 		    ZIO_FLAG_MUSTSUCCEED);
1144 		ka.usedp = &used;
1145 		ka.compressedp = &compressed;
1146 		ka.uncompressedp = &uncompressed;
1147 		ka.zio = zio;
1148 		ka.tx = tx;
1149 		(void) traverse_dsl_dataset(ds, ds->ds_phys->ds_prev_snap_txg,
1150 		    ADVANCE_POST, kill_blkptr, &ka);
1151 		(void) zio_wait(zio);
1152 
1153 		/* only deduct space beyond any refreservation */
1154 		delta = parent_delta(ds, -used);
1155 		dsl_dir_diduse_space(ds->ds_dir,
1156 		    delta, -compressed, -uncompressed, tx);
1157 	}
1158 
1159 	if (ds->ds_prev) {
1160 		/* Change our contents to that of the prev snapshot */
1161 		ASSERT3U(ds->ds_prev->ds_object, ==,
1162 		    ds->ds_phys->ds_prev_snap_obj);
1163 		ds->ds_phys->ds_bp = ds->ds_prev->ds_phys->ds_bp;
1164 		ds->ds_phys->ds_used_bytes =
1165 		    ds->ds_prev->ds_phys->ds_used_bytes;
1166 		ds->ds_phys->ds_compressed_bytes =
1167 		    ds->ds_prev->ds_phys->ds_compressed_bytes;
1168 		ds->ds_phys->ds_uncompressed_bytes =
1169 		    ds->ds_prev->ds_phys->ds_uncompressed_bytes;
1170 		ds->ds_phys->ds_flags = ds->ds_prev->ds_phys->ds_flags;
1171 		ds->ds_phys->ds_unique_bytes = 0;
1172 
1173 		if (ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) {
1174 			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1175 			ds->ds_prev->ds_phys->ds_unique_bytes = 0;
1176 		}
1177 	} else {
1178 		/* Zero out our contents, recreate objset */
1179 		bzero(&ds->ds_phys->ds_bp, sizeof (blkptr_t));
1180 		ds->ds_phys->ds_used_bytes = 0;
1181 		ds->ds_phys->ds_compressed_bytes = 0;
1182 		ds->ds_phys->ds_uncompressed_bytes = 0;
1183 		ds->ds_phys->ds_flags = 0;
1184 		ds->ds_phys->ds_unique_bytes = 0;
1185 		(void) dmu_objset_create_impl(ds->ds_dir->dd_pool->dp_spa, ds,
1186 		    &ds->ds_phys->ds_bp, *ost, tx);
1187 	}
1188 
1189 	spa_history_internal_log(LOG_DS_ROLLBACK, ds->ds_dir->dd_pool->dp_spa,
1190 	    tx, cr, "dataset = %llu", ds->ds_object);
1191 }
1192 
1193 /* ARGSUSED */
1194 static int
1195 dsl_dataset_destroy_begin_check(void *arg1, void *arg2, dmu_tx_t *tx)
1196 {
1197 	dsl_dataset_t *ds = arg1;
1198 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1199 	uint64_t count;
1200 	int err;
1201 
1202 	/*
1203 	 * Can't delete a head dataset if there are snapshots of it.
1204 	 * (Except if the only snapshots are from the branch we cloned
1205 	 * from.)
1206 	 */
1207 	if (ds->ds_prev != NULL &&
1208 	    ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object)
1209 		return (EINVAL);
1210 
1211 	/*
1212 	 * This is really a dsl_dir thing, but check it here so that
1213 	 * we'll be less likely to leave this dataset inconsistent &
1214 	 * nearly destroyed.
1215 	 */
1216 	err = zap_count(mos, ds->ds_dir->dd_phys->dd_child_dir_zapobj, &count);
1217 	if (err)
1218 		return (err);
1219 	if (count != 0)
1220 		return (EEXIST);
1221 
1222 	return (0);
1223 }
1224 
1225 /* ARGSUSED */
1226 static void
1227 dsl_dataset_destroy_begin_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1228 {
1229 	dsl_dataset_t *ds = arg1;
1230 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1231 
1232 	/* Mark it as inconsistent on-disk, in case we crash */
1233 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1234 	ds->ds_phys->ds_flags |= DS_FLAG_INCONSISTENT;
1235 
1236 	spa_history_internal_log(LOG_DS_DESTROY_BEGIN, dp->dp_spa, tx,
1237 	    cr, "dataset = %llu", ds->ds_object);
1238 }
1239 
1240 /* ARGSUSED */
1241 int
1242 dsl_dataset_destroy_check(void *arg1, void *arg2, dmu_tx_t *tx)
1243 {
1244 	dsl_dataset_t *ds = arg1;
1245 
1246 	/* Can't delete a branch point. */
1247 	if (ds->ds_phys->ds_num_children > 1)
1248 		return (EEXIST);
1249 
1250 	/*
1251 	 * Can't delete a head dataset if there are snapshots of it.
1252 	 * (Except if the only snapshots are from the branch we cloned
1253 	 * from.)
1254 	 */
1255 	if (ds->ds_prev != NULL &&
1256 	    ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object)
1257 		return (EINVAL);
1258 
1259 	/*
1260 	 * If we made changes this txg, traverse_dsl_dataset won't find
1261 	 * them.  Try again.
1262 	 */
1263 	if (ds->ds_phys->ds_bp.blk_birth >= tx->tx_txg)
1264 		return (EAGAIN);
1265 
1266 	/* XXX we should do some i/o error checking... */
1267 	return (0);
1268 }
1269 
1270 void
1271 dsl_dataset_destroy_sync(void *arg1, void *tag, cred_t *cr, dmu_tx_t *tx)
1272 {
1273 	dsl_dataset_t *ds = arg1;
1274 	int64_t used = 0, compressed = 0, uncompressed = 0;
1275 	zio_t *zio;
1276 	int err;
1277 	int after_branch_point = FALSE;
1278 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1279 	objset_t *mos = dp->dp_meta_objset;
1280 	dsl_dataset_t *ds_prev = NULL;
1281 	uint64_t obj;
1282 
1283 	ASSERT3U(ds->ds_open_refcount, ==, DS_REF_MAX);
1284 	ASSERT3U(ds->ds_phys->ds_num_children, <=, 1);
1285 	ASSERT(ds->ds_prev == NULL ||
1286 	    ds->ds_prev->ds_phys->ds_next_snap_obj != ds->ds_object);
1287 	ASSERT3U(ds->ds_phys->ds_bp.blk_birth, <=, tx->tx_txg);
1288 
1289 	/* Remove our reservation */
1290 	if (ds->ds_reserved != 0) {
1291 		uint64_t val = 0;
1292 		dsl_dataset_set_reservation_sync(ds, &val, cr, tx);
1293 		ASSERT3U(ds->ds_reserved, ==, 0);
1294 	}
1295 
1296 	ASSERT(RW_WRITE_HELD(&dp->dp_config_rwlock));
1297 
1298 	obj = ds->ds_object;
1299 
1300 	if (ds->ds_phys->ds_prev_snap_obj != 0) {
1301 		if (ds->ds_prev) {
1302 			ds_prev = ds->ds_prev;
1303 		} else {
1304 			VERIFY(0 == dsl_dataset_open_obj(dp,
1305 			    ds->ds_phys->ds_prev_snap_obj, NULL,
1306 			    DS_MODE_NONE, FTAG, &ds_prev));
1307 		}
1308 		after_branch_point =
1309 		    (ds_prev->ds_phys->ds_next_snap_obj != obj);
1310 
1311 		dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
1312 		if (after_branch_point &&
1313 		    ds->ds_phys->ds_next_snap_obj == 0) {
1314 			/* This clone is toast. */
1315 			ASSERT(ds_prev->ds_phys->ds_num_children > 1);
1316 			ds_prev->ds_phys->ds_num_children--;
1317 		} else if (!after_branch_point) {
1318 			ds_prev->ds_phys->ds_next_snap_obj =
1319 			    ds->ds_phys->ds_next_snap_obj;
1320 		}
1321 	}
1322 
1323 	zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
1324 
1325 	if (ds->ds_phys->ds_next_snap_obj != 0) {
1326 		blkptr_t bp;
1327 		dsl_dataset_t *ds_next;
1328 		uint64_t itor = 0;
1329 		uint64_t old_unique;
1330 
1331 		spa_scrub_restart(dp->dp_spa, tx->tx_txg);
1332 
1333 		VERIFY(0 == dsl_dataset_open_obj(dp,
1334 		    ds->ds_phys->ds_next_snap_obj, NULL,
1335 		    DS_MODE_NONE, FTAG, &ds_next));
1336 		ASSERT3U(ds_next->ds_phys->ds_prev_snap_obj, ==, obj);
1337 
1338 		old_unique = dsl_dataset_unique(ds_next);
1339 
1340 		dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
1341 		ds_next->ds_phys->ds_prev_snap_obj =
1342 		    ds->ds_phys->ds_prev_snap_obj;
1343 		ds_next->ds_phys->ds_prev_snap_txg =
1344 		    ds->ds_phys->ds_prev_snap_txg;
1345 		ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==,
1346 		    ds_prev ? ds_prev->ds_phys->ds_creation_txg : 0);
1347 
1348 		/*
1349 		 * Transfer to our deadlist (which will become next's
1350 		 * new deadlist) any entries from next's current
1351 		 * deadlist which were born before prev, and free the
1352 		 * other entries.
1353 		 *
1354 		 * XXX we're doing this long task with the config lock held
1355 		 */
1356 		while (bplist_iterate(&ds_next->ds_deadlist, &itor,
1357 		    &bp) == 0) {
1358 			if (bp.blk_birth <= ds->ds_phys->ds_prev_snap_txg) {
1359 				VERIFY(0 == bplist_enqueue(&ds->ds_deadlist,
1360 				    &bp, tx));
1361 				if (ds_prev && !after_branch_point &&
1362 				    bp.blk_birth >
1363 				    ds_prev->ds_phys->ds_prev_snap_txg) {
1364 					ds_prev->ds_phys->ds_unique_bytes +=
1365 					    bp_get_dasize(dp->dp_spa, &bp);
1366 				}
1367 			} else {
1368 				used += bp_get_dasize(dp->dp_spa, &bp);
1369 				compressed += BP_GET_PSIZE(&bp);
1370 				uncompressed += BP_GET_UCSIZE(&bp);
1371 				/* XXX check return value? */
1372 				(void) arc_free(zio, dp->dp_spa, tx->tx_txg,
1373 				    &bp, NULL, NULL, ARC_NOWAIT);
1374 			}
1375 		}
1376 
1377 		/* free next's deadlist */
1378 		bplist_close(&ds_next->ds_deadlist);
1379 		bplist_destroy(mos, ds_next->ds_phys->ds_deadlist_obj, tx);
1380 
1381 		/* set next's deadlist to our deadlist */
1382 		ds_next->ds_phys->ds_deadlist_obj =
1383 		    ds->ds_phys->ds_deadlist_obj;
1384 		VERIFY(0 == bplist_open(&ds_next->ds_deadlist, mos,
1385 		    ds_next->ds_phys->ds_deadlist_obj));
1386 		ds->ds_phys->ds_deadlist_obj = 0;
1387 
1388 		if (ds_next->ds_phys->ds_next_snap_obj != 0) {
1389 			/*
1390 			 * Update next's unique to include blocks which
1391 			 * were previously shared by only this snapshot
1392 			 * and it.  Those blocks will be born after the
1393 			 * prev snap and before this snap, and will have
1394 			 * died after the next snap and before the one
1395 			 * after that (ie. be on the snap after next's
1396 			 * deadlist).
1397 			 *
1398 			 * XXX we're doing this long task with the
1399 			 * config lock held
1400 			 */
1401 			dsl_dataset_t *ds_after_next;
1402 
1403 			VERIFY(0 == dsl_dataset_open_obj(dp,
1404 			    ds_next->ds_phys->ds_next_snap_obj, NULL,
1405 			    DS_MODE_NONE, FTAG, &ds_after_next));
1406 			itor = 0;
1407 			while (bplist_iterate(&ds_after_next->ds_deadlist,
1408 			    &itor, &bp) == 0) {
1409 				if (bp.blk_birth >
1410 				    ds->ds_phys->ds_prev_snap_txg &&
1411 				    bp.blk_birth <=
1412 				    ds->ds_phys->ds_creation_txg) {
1413 					ds_next->ds_phys->ds_unique_bytes +=
1414 					    bp_get_dasize(dp->dp_spa, &bp);
1415 				}
1416 			}
1417 
1418 			dsl_dataset_close(ds_after_next, DS_MODE_NONE, FTAG);
1419 			ASSERT3P(ds_next->ds_prev, ==, NULL);
1420 		} else {
1421 			ASSERT3P(ds_next->ds_prev, ==, ds);
1422 			dsl_dataset_close(ds_next->ds_prev, DS_MODE_NONE,
1423 			    ds_next);
1424 			if (ds_prev) {
1425 				VERIFY(0 == dsl_dataset_open_obj(dp,
1426 				    ds->ds_phys->ds_prev_snap_obj, NULL,
1427 				    DS_MODE_NONE, ds_next, &ds_next->ds_prev));
1428 			} else {
1429 				ds_next->ds_prev = NULL;
1430 			}
1431 
1432 			dsl_dataset_recalc_head_uniq(ds_next);
1433 
1434 			/*
1435 			 * Reduce the amount of our unconsmed refreservation
1436 			 * being charged to our parent by the amount of
1437 			 * new unique data we have gained.
1438 			 */
1439 			if (old_unique < ds_next->ds_reserved) {
1440 				int64_t mrsdelta;
1441 				uint64_t new_unique =
1442 				    ds_next->ds_phys->ds_unique_bytes;
1443 
1444 				ASSERT(old_unique <= new_unique);
1445 				mrsdelta = MIN(new_unique - old_unique,
1446 				    ds_next->ds_reserved - old_unique);
1447 				dsl_dir_diduse_space(ds->ds_dir, -mrsdelta,
1448 				    0, 0, tx);
1449 			}
1450 		}
1451 		dsl_dataset_close(ds_next, DS_MODE_NONE, FTAG);
1452 
1453 		/*
1454 		 * NB: unique_bytes might not be accurate for the head objset.
1455 		 * Before SPA_VERSION 9, we didn't update its value when we
1456 		 * deleted the most recent snapshot.
1457 		 */
1458 		ASSERT3U(used, ==, ds->ds_phys->ds_unique_bytes);
1459 	} else {
1460 		/*
1461 		 * There's no next snapshot, so this is a head dataset.
1462 		 * Destroy the deadlist.  Unless it's a clone, the
1463 		 * deadlist should be empty.  (If it's a clone, it's
1464 		 * safe to ignore the deadlist contents.)
1465 		 */
1466 		struct killarg ka;
1467 
1468 		ASSERT(after_branch_point || bplist_empty(&ds->ds_deadlist));
1469 		bplist_close(&ds->ds_deadlist);
1470 		bplist_destroy(mos, ds->ds_phys->ds_deadlist_obj, tx);
1471 		ds->ds_phys->ds_deadlist_obj = 0;
1472 
1473 		/*
1474 		 * Free everything that we point to (that's born after
1475 		 * the previous snapshot, if we are a clone)
1476 		 *
1477 		 * XXX we're doing this long task with the config lock held
1478 		 */
1479 		ka.usedp = &used;
1480 		ka.compressedp = &compressed;
1481 		ka.uncompressedp = &uncompressed;
1482 		ka.zio = zio;
1483 		ka.tx = tx;
1484 		err = traverse_dsl_dataset(ds, ds->ds_phys->ds_prev_snap_txg,
1485 		    ADVANCE_POST, kill_blkptr, &ka);
1486 		ASSERT3U(err, ==, 0);
1487 		ASSERT(spa_version(dp->dp_spa) <
1488 		    SPA_VERSION_UNIQUE_ACCURATE ||
1489 		    used == ds->ds_phys->ds_unique_bytes);
1490 	}
1491 
1492 	err = zio_wait(zio);
1493 	ASSERT3U(err, ==, 0);
1494 
1495 	dsl_dir_diduse_space(ds->ds_dir, -used, -compressed, -uncompressed, tx);
1496 
1497 	if (ds->ds_phys->ds_snapnames_zapobj) {
1498 		err = zap_destroy(mos, ds->ds_phys->ds_snapnames_zapobj, tx);
1499 		ASSERT(err == 0);
1500 	}
1501 
1502 	if (ds->ds_dir->dd_phys->dd_head_dataset_obj == ds->ds_object) {
1503 		/* Erase the link in the dataset */
1504 		dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
1505 		ds->ds_dir->dd_phys->dd_head_dataset_obj = 0;
1506 		/*
1507 		 * dsl_dir_sync_destroy() called us, they'll destroy
1508 		 * the dataset.
1509 		 */
1510 	} else {
1511 		/* remove from snapshot namespace */
1512 		dsl_dataset_t *ds_head;
1513 		VERIFY(0 == dsl_dataset_open_obj(dp,
1514 		    ds->ds_dir->dd_phys->dd_head_dataset_obj, NULL,
1515 		    DS_MODE_NONE, FTAG, &ds_head));
1516 		VERIFY(0 == dsl_dataset_get_snapname(ds));
1517 #ifdef ZFS_DEBUG
1518 		{
1519 			uint64_t val;
1520 			err = zap_lookup(mos,
1521 			    ds_head->ds_phys->ds_snapnames_zapobj,
1522 			    ds->ds_snapname, 8, 1, &val);
1523 			ASSERT3U(err, ==, 0);
1524 			ASSERT3U(val, ==, obj);
1525 		}
1526 #endif
1527 		err = zap_remove(mos, ds_head->ds_phys->ds_snapnames_zapobj,
1528 		    ds->ds_snapname, tx);
1529 		ASSERT(err == 0);
1530 		dsl_dataset_close(ds_head, DS_MODE_NONE, FTAG);
1531 	}
1532 
1533 	if (ds_prev && ds->ds_prev != ds_prev)
1534 		dsl_dataset_close(ds_prev, DS_MODE_NONE, FTAG);
1535 
1536 	spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
1537 	spa_history_internal_log(LOG_DS_DESTROY, dp->dp_spa, tx,
1538 	    cr, "dataset = %llu", ds->ds_object);
1539 
1540 	dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, tag);
1541 	VERIFY(0 == dmu_object_free(mos, obj, tx));
1542 
1543 }
1544 
1545 static int
1546 dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx)
1547 {
1548 	uint64_t asize;
1549 
1550 	if (!dmu_tx_is_syncing(tx))
1551 		return (0);
1552 
1553 	/*
1554 	 * If there's an fs-only reservation, any blocks that might become
1555 	 * owned by the snapshot dataset must be accommodated by space
1556 	 * outside of the reservation.
1557 	 */
1558 	asize = MIN(dsl_dataset_unique(ds), ds->ds_reserved);
1559 	if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, FALSE))
1560 		return (ENOSPC);
1561 
1562 	/*
1563 	 * Propogate any reserved space for this snapshot to other
1564 	 * snapshot checks in this sync group.
1565 	 */
1566 	if (asize > 0)
1567 		dsl_dir_willuse_space(ds->ds_dir, asize, tx);
1568 
1569 	return (0);
1570 }
1571 
1572 /* ARGSUSED */
1573 int
1574 dsl_dataset_snapshot_check(void *arg1, void *arg2, dmu_tx_t *tx)
1575 {
1576 	dsl_dataset_t *ds = arg1;
1577 	const char *snapname = arg2;
1578 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1579 	int err;
1580 	uint64_t value;
1581 
1582 	/*
1583 	 * We don't allow multiple snapshots of the same txg.  If there
1584 	 * is already one, try again.
1585 	 */
1586 	if (ds->ds_phys->ds_prev_snap_txg >= tx->tx_txg)
1587 		return (EAGAIN);
1588 
1589 	/*
1590 	 * Check for conflicting name snapshot name.
1591 	 */
1592 	err = zap_lookup(mos, ds->ds_phys->ds_snapnames_zapobj,
1593 	    snapname, 8, 1, &value);
1594 	if (err == 0)
1595 		return (EEXIST);
1596 	if (err != ENOENT)
1597 		return (err);
1598 
1599 	/*
1600 	 * Check that the dataset's name is not too long.  Name consists
1601 	 * of the dataset's length + 1 for the @-sign + snapshot name's length
1602 	 */
1603 	if (dsl_dataset_namelen(ds) + 1 + strlen(snapname) >= MAXNAMELEN)
1604 		return (ENAMETOOLONG);
1605 
1606 	err = dsl_dataset_snapshot_reserve_space(ds, tx);
1607 	if (err)
1608 		return (err);
1609 
1610 	ds->ds_trysnap_txg = tx->tx_txg;
1611 	return (0);
1612 }
1613 
1614 void
1615 dsl_dataset_snapshot_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
1616 {
1617 	dsl_dataset_t *ds = arg1;
1618 	const char *snapname = arg2;
1619 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1620 	dmu_buf_t *dbuf;
1621 	dsl_dataset_phys_t *dsphys;
1622 	uint64_t dsobj;
1623 	objset_t *mos = dp->dp_meta_objset;
1624 	int err;
1625 
1626 	spa_scrub_restart(dp->dp_spa, tx->tx_txg);
1627 	ASSERT(RW_WRITE_HELD(&dp->dp_config_rwlock));
1628 
1629 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1630 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1631 	VERIFY(0 == dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1632 	dmu_buf_will_dirty(dbuf, tx);
1633 	dsphys = dbuf->db_data;
1634 	dsphys->ds_dir_obj = ds->ds_dir->dd_object;
1635 	dsphys->ds_fsid_guid = unique_create();
1636 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1637 	    sizeof (dsphys->ds_guid));
1638 	dsphys->ds_prev_snap_obj = ds->ds_phys->ds_prev_snap_obj;
1639 	dsphys->ds_prev_snap_txg = ds->ds_phys->ds_prev_snap_txg;
1640 	dsphys->ds_next_snap_obj = ds->ds_object;
1641 	dsphys->ds_num_children = 1;
1642 	dsphys->ds_creation_time = gethrestime_sec();
1643 	dsphys->ds_creation_txg = tx->tx_txg;
1644 	dsphys->ds_deadlist_obj = ds->ds_phys->ds_deadlist_obj;
1645 	dsphys->ds_used_bytes = ds->ds_phys->ds_used_bytes;
1646 	dsphys->ds_compressed_bytes = ds->ds_phys->ds_compressed_bytes;
1647 	dsphys->ds_uncompressed_bytes = ds->ds_phys->ds_uncompressed_bytes;
1648 	dsphys->ds_flags = ds->ds_phys->ds_flags;
1649 	dsphys->ds_bp = ds->ds_phys->ds_bp;
1650 	dmu_buf_rele(dbuf, FTAG);
1651 
1652 	ASSERT3U(ds->ds_prev != 0, ==, ds->ds_phys->ds_prev_snap_obj != 0);
1653 	if (ds->ds_prev) {
1654 		ASSERT(ds->ds_prev->ds_phys->ds_next_snap_obj ==
1655 		    ds->ds_object ||
1656 		    ds->ds_prev->ds_phys->ds_num_children > 1);
1657 		if (ds->ds_prev->ds_phys->ds_next_snap_obj == ds->ds_object) {
1658 			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1659 			ASSERT3U(ds->ds_phys->ds_prev_snap_txg, ==,
1660 			    ds->ds_prev->ds_phys->ds_creation_txg);
1661 			ds->ds_prev->ds_phys->ds_next_snap_obj = dsobj;
1662 		}
1663 	}
1664 
1665 	/*
1666 	 * If we have a reference-reservation on this dataset, we will
1667 	 * need to increase the amount of refreservation being charged
1668 	 * since our unique space is going to zero.
1669 	 */
1670 	if (ds->ds_reserved) {
1671 		int64_t add = MIN(dsl_dataset_unique(ds), ds->ds_reserved);
1672 		dsl_dir_diduse_space(ds->ds_dir, add, 0, 0, tx);
1673 	}
1674 
1675 	bplist_close(&ds->ds_deadlist);
1676 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1677 	ASSERT3U(ds->ds_phys->ds_prev_snap_txg, <, dsphys->ds_creation_txg);
1678 	ds->ds_phys->ds_prev_snap_obj = dsobj;
1679 	ds->ds_phys->ds_prev_snap_txg = dsphys->ds_creation_txg;
1680 	ds->ds_phys->ds_unique_bytes = 0;
1681 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1682 		ds->ds_phys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1683 	ds->ds_phys->ds_deadlist_obj =
1684 	    bplist_create(mos, DSL_DEADLIST_BLOCKSIZE, tx);
1685 	VERIFY(0 == bplist_open(&ds->ds_deadlist, mos,
1686 	    ds->ds_phys->ds_deadlist_obj));
1687 
1688 	dprintf("snap '%s' -> obj %llu\n", snapname, dsobj);
1689 	err = zap_add(mos, ds->ds_phys->ds_snapnames_zapobj,
1690 	    snapname, 8, 1, &dsobj, tx);
1691 	ASSERT(err == 0);
1692 
1693 	if (ds->ds_prev)
1694 		dsl_dataset_close(ds->ds_prev, DS_MODE_NONE, ds);
1695 	VERIFY(0 == dsl_dataset_open_obj(dp,
1696 	    ds->ds_phys->ds_prev_snap_obj, snapname,
1697 	    DS_MODE_NONE, ds, &ds->ds_prev));
1698 
1699 	spa_history_internal_log(LOG_DS_SNAPSHOT, dp->dp_spa, tx, cr,
1700 	    "dataset = %llu", dsobj);
1701 }
1702 
1703 void
1704 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
1705 {
1706 	ASSERT(dmu_tx_is_syncing(tx));
1707 	ASSERT(ds->ds_user_ptr != NULL);
1708 	ASSERT(ds->ds_phys->ds_next_snap_obj == 0);
1709 
1710 	/*
1711 	 * in case we had to change ds_fsid_guid when we opened it,
1712 	 * sync it out now.
1713 	 */
1714 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1715 	ds->ds_phys->ds_fsid_guid = ds->ds_fsid_guid;
1716 
1717 	dsl_dir_dirty(ds->ds_dir, tx);
1718 	dmu_objset_sync(ds->ds_user_ptr, zio, tx);
1719 }
1720 
1721 void
1722 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
1723 {
1724 	uint64_t refd, avail, uobjs, aobjs;
1725 
1726 	dsl_dir_stats(ds->ds_dir, nv);
1727 
1728 	dsl_dataset_space(ds, &refd, &avail, &uobjs, &aobjs);
1729 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE, avail);
1730 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED, refd);
1731 
1732 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION,
1733 	    ds->ds_phys->ds_creation_time);
1734 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG,
1735 	    ds->ds_phys->ds_creation_txg);
1736 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA,
1737 	    ds->ds_quota);
1738 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION,
1739 	    ds->ds_reserved);
1740 
1741 	if (ds->ds_phys->ds_next_snap_obj) {
1742 		/*
1743 		 * This is a snapshot; override the dd's space used with
1744 		 * our unique space and compression ratio.
1745 		 */
1746 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
1747 		    ds->ds_phys->ds_unique_bytes);
1748 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
1749 		    ds->ds_phys->ds_compressed_bytes == 0 ? 100 :
1750 		    (ds->ds_phys->ds_uncompressed_bytes * 100 /
1751 		    ds->ds_phys->ds_compressed_bytes));
1752 	}
1753 }
1754 
1755 void
1756 dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat)
1757 {
1758 	stat->dds_creation_txg = ds->ds_phys->ds_creation_txg;
1759 	stat->dds_inconsistent = ds->ds_phys->ds_flags & DS_FLAG_INCONSISTENT;
1760 	stat->dds_guid = ds->ds_phys->ds_guid;
1761 	if (ds->ds_phys->ds_next_snap_obj) {
1762 		stat->dds_is_snapshot = B_TRUE;
1763 		stat->dds_num_clones = ds->ds_phys->ds_num_children - 1;
1764 	}
1765 
1766 	/* clone origin is really a dsl_dir thing... */
1767 	rw_enter(&ds->ds_dir->dd_pool->dp_config_rwlock, RW_READER);
1768 	if (ds->ds_dir->dd_phys->dd_origin_obj) {
1769 		dsl_dataset_t *ods;
1770 
1771 		VERIFY(0 == dsl_dataset_open_obj(ds->ds_dir->dd_pool,
1772 		    ds->ds_dir->dd_phys->dd_origin_obj,
1773 		    NULL, DS_MODE_NONE, FTAG, &ods));
1774 		dsl_dataset_name(ods, stat->dds_origin);
1775 		dsl_dataset_close(ods, DS_MODE_NONE, FTAG);
1776 	}
1777 	rw_exit(&ds->ds_dir->dd_pool->dp_config_rwlock);
1778 }
1779 
1780 uint64_t
1781 dsl_dataset_fsid_guid(dsl_dataset_t *ds)
1782 {
1783 	return (ds->ds_fsid_guid);
1784 }
1785 
1786 void
1787 dsl_dataset_space(dsl_dataset_t *ds,
1788     uint64_t *refdbytesp, uint64_t *availbytesp,
1789     uint64_t *usedobjsp, uint64_t *availobjsp)
1790 {
1791 	*refdbytesp = ds->ds_phys->ds_used_bytes;
1792 	*availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE);
1793 	if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes)
1794 		*availbytesp += ds->ds_reserved - ds->ds_phys->ds_unique_bytes;
1795 	if (ds->ds_quota != 0) {
1796 		/*
1797 		 * Adjust available bytes according to refquota
1798 		 */
1799 		if (*refdbytesp < ds->ds_quota)
1800 			*availbytesp = MIN(*availbytesp,
1801 			    ds->ds_quota - *refdbytesp);
1802 		else
1803 			*availbytesp = 0;
1804 	}
1805 	*usedobjsp = ds->ds_phys->ds_bp.blk_fill;
1806 	*availobjsp = DN_MAX_OBJECT - *usedobjsp;
1807 }
1808 
1809 boolean_t
1810 dsl_dataset_modified_since_lastsnap(dsl_dataset_t *ds)
1811 {
1812 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1813 
1814 	ASSERT(RW_LOCK_HELD(&dp->dp_config_rwlock) ||
1815 	    dsl_pool_sync_context(dp));
1816 	if (ds->ds_prev == NULL)
1817 		return (B_FALSE);
1818 	if (ds->ds_phys->ds_bp.blk_birth >
1819 	    ds->ds_prev->ds_phys->ds_creation_txg)
1820 		return (B_TRUE);
1821 	return (B_FALSE);
1822 }
1823 
1824 /* ARGSUSED */
1825 static int
1826 dsl_dataset_snapshot_rename_check(void *arg1, void *arg2, dmu_tx_t *tx)
1827 {
1828 	dsl_dataset_t *ds = arg1;
1829 	char *newsnapname = arg2;
1830 	dsl_dir_t *dd = ds->ds_dir;
1831 	objset_t *mos = dd->dd_pool->dp_meta_objset;
1832 	dsl_dataset_t *hds;
1833 	uint64_t val;
1834 	int err;
1835 
1836 	err = dsl_dataset_open_obj(dd->dd_pool,
1837 	    dd->dd_phys->dd_head_dataset_obj, NULL, DS_MODE_NONE, FTAG, &hds);
1838 	if (err)
1839 		return (err);
1840 
1841 	/* new name better not be in use */
1842 	err = zap_lookup(mos, hds->ds_phys->ds_snapnames_zapobj,
1843 	    newsnapname, 8, 1, &val);
1844 	dsl_dataset_close(hds, DS_MODE_NONE, FTAG);
1845 
1846 	if (err == 0)
1847 		err = EEXIST;
1848 	else if (err == ENOENT)
1849 		err = 0;
1850 
1851 	/* dataset name + 1 for the "@" + the new snapshot name must fit */
1852 	if (dsl_dir_namelen(ds->ds_dir) + 1 + strlen(newsnapname) >= MAXNAMELEN)
1853 		err = ENAMETOOLONG;
1854 
1855 	return (err);
1856 }
1857 
1858 static void
1859 dsl_dataset_snapshot_rename_sync(void *arg1, void *arg2,
1860     cred_t *cr, dmu_tx_t *tx)
1861 {
1862 	dsl_dataset_t *ds = arg1;
1863 	const char *newsnapname = arg2;
1864 	dsl_dir_t *dd = ds->ds_dir;
1865 	objset_t *mos = dd->dd_pool->dp_meta_objset;
1866 	dsl_dataset_t *hds;
1867 	int err;
1868 
1869 	ASSERT(ds->ds_phys->ds_next_snap_obj != 0);
1870 
1871 	VERIFY(0 == dsl_dataset_open_obj(dd->dd_pool,
1872 	    dd->dd_phys->dd_head_dataset_obj, NULL, DS_MODE_NONE, FTAG, &hds));
1873 
1874 	VERIFY(0 == dsl_dataset_get_snapname(ds));
1875 	err = zap_remove(mos, hds->ds_phys->ds_snapnames_zapobj,
1876 	    ds->ds_snapname, tx);
1877 	ASSERT3U(err, ==, 0);
1878 	mutex_enter(&ds->ds_lock);
1879 	(void) strcpy(ds->ds_snapname, newsnapname);
1880 	mutex_exit(&ds->ds_lock);
1881 	err = zap_add(mos, hds->ds_phys->ds_snapnames_zapobj,
1882 	    ds->ds_snapname, 8, 1, &ds->ds_object, tx);
1883 	ASSERT3U(err, ==, 0);
1884 
1885 	spa_history_internal_log(LOG_DS_RENAME, dd->dd_pool->dp_spa, tx,
1886 	    cr, "dataset = %llu", ds->ds_object);
1887 	dsl_dataset_close(hds, DS_MODE_NONE, FTAG);
1888 }
1889 
1890 struct renamesnaparg {
1891 	dsl_sync_task_group_t *dstg;
1892 	char failed[MAXPATHLEN];
1893 	char *oldsnap;
1894 	char *newsnap;
1895 };
1896 
1897 static int
1898 dsl_snapshot_rename_one(char *name, void *arg)
1899 {
1900 	struct renamesnaparg *ra = arg;
1901 	dsl_dataset_t *ds = NULL;
1902 	char *cp;
1903 	int err;
1904 
1905 	cp = name + strlen(name);
1906 	*cp = '@';
1907 	(void) strcpy(cp + 1, ra->oldsnap);
1908 
1909 	/*
1910 	 * For recursive snapshot renames the parent won't be changing
1911 	 * so we just pass name for both the to/from argument.
1912 	 */
1913 	if (err = zfs_secpolicy_rename_perms(name, name, CRED())) {
1914 		(void) strcpy(ra->failed, name);
1915 		return (err);
1916 	}
1917 
1918 	err = dsl_dataset_open(name, DS_MODE_READONLY | DS_MODE_STANDARD,
1919 	    ra->dstg, &ds);
1920 	if (err == ENOENT) {
1921 		*cp = '\0';
1922 		return (0);
1923 	}
1924 	if (err) {
1925 		(void) strcpy(ra->failed, name);
1926 		*cp = '\0';
1927 		dsl_dataset_close(ds, DS_MODE_STANDARD, ra->dstg);
1928 		return (err);
1929 	}
1930 
1931 #ifdef _KERNEL
1932 	/* for all filesystems undergoing rename, we'll need to unmount it */
1933 	(void) zfs_unmount_snap(name, NULL);
1934 #endif
1935 
1936 	*cp = '\0';
1937 
1938 	dsl_sync_task_create(ra->dstg, dsl_dataset_snapshot_rename_check,
1939 	    dsl_dataset_snapshot_rename_sync, ds, ra->newsnap, 0);
1940 
1941 	return (0);
1942 }
1943 
1944 static int
1945 dsl_recursive_rename(char *oldname, const char *newname)
1946 {
1947 	int err;
1948 	struct renamesnaparg *ra;
1949 	dsl_sync_task_t *dst;
1950 	spa_t *spa;
1951 	char *cp, *fsname = spa_strdup(oldname);
1952 	int len = strlen(oldname);
1953 
1954 	/* truncate the snapshot name to get the fsname */
1955 	cp = strchr(fsname, '@');
1956 	*cp = '\0';
1957 
1958 	err = spa_open(fsname, &spa, FTAG);
1959 	if (err) {
1960 		kmem_free(fsname, len + 1);
1961 		return (err);
1962 	}
1963 	ra = kmem_alloc(sizeof (struct renamesnaparg), KM_SLEEP);
1964 	ra->dstg = dsl_sync_task_group_create(spa_get_dsl(spa));
1965 
1966 	ra->oldsnap = strchr(oldname, '@') + 1;
1967 	ra->newsnap = strchr(newname, '@') + 1;
1968 	*ra->failed = '\0';
1969 
1970 	err = dmu_objset_find(fsname, dsl_snapshot_rename_one, ra,
1971 	    DS_FIND_CHILDREN);
1972 	kmem_free(fsname, len + 1);
1973 
1974 	if (err == 0) {
1975 		err = dsl_sync_task_group_wait(ra->dstg);
1976 	}
1977 
1978 	for (dst = list_head(&ra->dstg->dstg_tasks); dst;
1979 	    dst = list_next(&ra->dstg->dstg_tasks, dst)) {
1980 		dsl_dataset_t *ds = dst->dst_arg1;
1981 		if (dst->dst_err) {
1982 			dsl_dir_name(ds->ds_dir, ra->failed);
1983 			(void) strcat(ra->failed, "@");
1984 			(void) strcat(ra->failed, ra->newsnap);
1985 		}
1986 		dsl_dataset_close(ds, DS_MODE_STANDARD, ra->dstg);
1987 	}
1988 
1989 	if (err)
1990 		(void) strcpy(oldname, ra->failed);
1991 
1992 	dsl_sync_task_group_destroy(ra->dstg);
1993 	kmem_free(ra, sizeof (struct renamesnaparg));
1994 	spa_close(spa, FTAG);
1995 	return (err);
1996 }
1997 
1998 static int
1999 dsl_valid_rename(char *oldname, void *arg)
2000 {
2001 	int delta = *(int *)arg;
2002 
2003 	if (strlen(oldname) + delta >= MAXNAMELEN)
2004 		return (ENAMETOOLONG);
2005 
2006 	return (0);
2007 }
2008 
2009 #pragma weak dmu_objset_rename = dsl_dataset_rename
2010 int
2011 dsl_dataset_rename(char *oldname, const char *newname,
2012     boolean_t recursive)
2013 {
2014 	dsl_dir_t *dd;
2015 	dsl_dataset_t *ds;
2016 	const char *tail;
2017 	int err;
2018 
2019 	err = dsl_dir_open(oldname, FTAG, &dd, &tail);
2020 	if (err)
2021 		return (err);
2022 	if (tail == NULL) {
2023 		int delta = strlen(newname) - strlen(oldname);
2024 
2025 		/* if we're growing, validate child size lengths */
2026 		if (delta > 0)
2027 			err = dmu_objset_find(oldname, dsl_valid_rename,
2028 			    &delta, DS_FIND_CHILDREN | DS_FIND_SNAPSHOTS);
2029 
2030 		if (!err)
2031 			err = dsl_dir_rename(dd, newname);
2032 		dsl_dir_close(dd, FTAG);
2033 		return (err);
2034 	}
2035 	if (tail[0] != '@') {
2036 		/* the name ended in a nonexistant component */
2037 		dsl_dir_close(dd, FTAG);
2038 		return (ENOENT);
2039 	}
2040 
2041 	dsl_dir_close(dd, FTAG);
2042 
2043 	/* new name must be snapshot in same filesystem */
2044 	tail = strchr(newname, '@');
2045 	if (tail == NULL)
2046 		return (EINVAL);
2047 	tail++;
2048 	if (strncmp(oldname, newname, tail - newname) != 0)
2049 		return (EXDEV);
2050 
2051 	if (recursive) {
2052 		err = dsl_recursive_rename(oldname, newname);
2053 	} else {
2054 		err = dsl_dataset_open(oldname,
2055 		    DS_MODE_READONLY | DS_MODE_STANDARD, FTAG, &ds);
2056 		if (err)
2057 			return (err);
2058 
2059 		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
2060 		    dsl_dataset_snapshot_rename_check,
2061 		    dsl_dataset_snapshot_rename_sync, ds, (char *)tail, 1);
2062 
2063 		dsl_dataset_close(ds, DS_MODE_STANDARD, FTAG);
2064 	}
2065 
2066 	return (err);
2067 }
2068 
2069 struct promotearg {
2070 	uint64_t used, comp, uncomp, unique;
2071 	uint64_t newnext_obj, snapnames_obj;
2072 };
2073 
2074 /* ARGSUSED */
2075 static int
2076 dsl_dataset_promote_check(void *arg1, void *arg2, dmu_tx_t *tx)
2077 {
2078 	dsl_dataset_t *hds = arg1;
2079 	struct promotearg *pa = arg2;
2080 	dsl_dir_t *dd = hds->ds_dir;
2081 	dsl_pool_t *dp = hds->ds_dir->dd_pool;
2082 	dsl_dir_t *odd = NULL;
2083 	dsl_dataset_t *ds = NULL;
2084 	dsl_dataset_t *origin_ds = NULL;
2085 	dsl_dataset_t *newnext_ds = NULL;
2086 	int err;
2087 	char *name = NULL;
2088 	uint64_t itor = 0;
2089 	blkptr_t bp;
2090 
2091 	bzero(pa, sizeof (*pa));
2092 
2093 	/* Check that it is a clone */
2094 	if (dd->dd_phys->dd_origin_obj == 0)
2095 		return (EINVAL);
2096 
2097 	/* Since this is so expensive, don't do the preliminary check */
2098 	if (!dmu_tx_is_syncing(tx))
2099 		return (0);
2100 
2101 	if (err = dsl_dataset_open_obj(dp, dd->dd_phys->dd_origin_obj,
2102 	    NULL, DS_MODE_EXCLUSIVE, FTAG, &origin_ds))
2103 		goto out;
2104 	odd = origin_ds->ds_dir;
2105 
2106 	{
2107 		dsl_dataset_t *phds;
2108 		if (err = dsl_dataset_open_obj(dd->dd_pool,
2109 		    odd->dd_phys->dd_head_dataset_obj,
2110 		    NULL, DS_MODE_NONE, FTAG, &phds))
2111 			goto out;
2112 		pa->snapnames_obj = phds->ds_phys->ds_snapnames_zapobj;
2113 		dsl_dataset_close(phds, DS_MODE_NONE, FTAG);
2114 	}
2115 
2116 	if (hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE) {
2117 		err = EXDEV;
2118 		goto out;
2119 	}
2120 
2121 	/* find origin's new next ds */
2122 	VERIFY(0 == dsl_dataset_open_obj(dd->dd_pool, hds->ds_object,
2123 	    NULL, DS_MODE_NONE, FTAG, &newnext_ds));
2124 	while (newnext_ds->ds_phys->ds_prev_snap_obj != origin_ds->ds_object) {
2125 		dsl_dataset_t *prev;
2126 
2127 		if (err = dsl_dataset_open_obj(dd->dd_pool,
2128 		    newnext_ds->ds_phys->ds_prev_snap_obj,
2129 		    NULL, DS_MODE_NONE, FTAG, &prev))
2130 			goto out;
2131 		dsl_dataset_close(newnext_ds, DS_MODE_NONE, FTAG);
2132 		newnext_ds = prev;
2133 	}
2134 	pa->newnext_obj = newnext_ds->ds_object;
2135 
2136 	/* compute origin's new unique space */
2137 	while ((err = bplist_iterate(&newnext_ds->ds_deadlist,
2138 	    &itor, &bp)) == 0) {
2139 		if (bp.blk_birth > origin_ds->ds_phys->ds_prev_snap_txg)
2140 			pa->unique += bp_get_dasize(dd->dd_pool->dp_spa, &bp);
2141 	}
2142 	if (err != ENOENT)
2143 		goto out;
2144 
2145 	/* Walk the snapshots that we are moving */
2146 	name = kmem_alloc(MAXPATHLEN, KM_SLEEP);
2147 	ds = origin_ds;
2148 	/* CONSTCOND */
2149 	while (TRUE) {
2150 		uint64_t val, dlused, dlcomp, dluncomp;
2151 		dsl_dataset_t *prev;
2152 
2153 		/* Check that the snapshot name does not conflict */
2154 		dsl_dataset_name(ds, name);
2155 		err = zap_lookup(dd->dd_pool->dp_meta_objset,
2156 		    hds->ds_phys->ds_snapnames_zapobj, ds->ds_snapname,
2157 		    8, 1, &val);
2158 		if (err != ENOENT) {
2159 			if (err == 0)
2160 				err = EEXIST;
2161 			goto out;
2162 		}
2163 
2164 		/*
2165 		 * compute space to transfer.  Each snapshot gave birth to:
2166 		 * (my used) - (prev's used) + (deadlist's used)
2167 		 */
2168 		pa->used += ds->ds_phys->ds_used_bytes;
2169 		pa->comp += ds->ds_phys->ds_compressed_bytes;
2170 		pa->uncomp += ds->ds_phys->ds_uncompressed_bytes;
2171 
2172 		/* If we reach the first snapshot, we're done. */
2173 		if (ds->ds_phys->ds_prev_snap_obj == 0)
2174 			break;
2175 
2176 		if (err = bplist_space(&ds->ds_deadlist,
2177 		    &dlused, &dlcomp, &dluncomp))
2178 			goto out;
2179 		if (err = dsl_dataset_open_obj(dd->dd_pool,
2180 		    ds->ds_phys->ds_prev_snap_obj, NULL, DS_MODE_EXCLUSIVE,
2181 		    FTAG, &prev))
2182 			goto out;
2183 		pa->used += dlused - prev->ds_phys->ds_used_bytes;
2184 		pa->comp += dlcomp - prev->ds_phys->ds_compressed_bytes;
2185 		pa->uncomp += dluncomp - prev->ds_phys->ds_uncompressed_bytes;
2186 
2187 		/*
2188 		 * We could be a clone of a clone.  If we reach our
2189 		 * parent's branch point, we're done.
2190 		 */
2191 		if (prev->ds_phys->ds_next_snap_obj != ds->ds_object) {
2192 			dsl_dataset_close(prev, DS_MODE_EXCLUSIVE, FTAG);
2193 			break;
2194 		}
2195 		if (ds != origin_ds)
2196 			dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
2197 		ds = prev;
2198 	}
2199 
2200 	/* Check that there is enough space here */
2201 	err = dsl_dir_transfer_possible(odd, dd, pa->used);
2202 
2203 out:
2204 	if (ds && ds != origin_ds)
2205 		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
2206 	if (origin_ds)
2207 		dsl_dataset_close(origin_ds, DS_MODE_EXCLUSIVE, FTAG);
2208 	if (newnext_ds)
2209 		dsl_dataset_close(newnext_ds, DS_MODE_NONE, FTAG);
2210 	if (name)
2211 		kmem_free(name, MAXPATHLEN);
2212 	return (err);
2213 }
2214 
2215 static void
2216 dsl_dataset_promote_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
2217 {
2218 	dsl_dataset_t *hds = arg1;
2219 	struct promotearg *pa = arg2;
2220 	dsl_dir_t *dd = hds->ds_dir;
2221 	dsl_pool_t *dp = hds->ds_dir->dd_pool;
2222 	dsl_dir_t *odd = NULL;
2223 	dsl_dataset_t *ds, *origin_ds;
2224 	char *name;
2225 
2226 	ASSERT(dd->dd_phys->dd_origin_obj != 0);
2227 	ASSERT(0 == (hds->ds_phys->ds_flags & DS_FLAG_NOPROMOTE));
2228 
2229 	VERIFY(0 == dsl_dataset_open_obj(dp, dd->dd_phys->dd_origin_obj,
2230 	    NULL, DS_MODE_EXCLUSIVE, FTAG, &origin_ds));
2231 	/*
2232 	 * We need to explicitly open odd, since origin_ds's dd will be
2233 	 * changing.
2234 	 */
2235 	VERIFY(0 == dsl_dir_open_obj(dp, origin_ds->ds_dir->dd_object,
2236 	    NULL, FTAG, &odd));
2237 
2238 	/* move snapshots to this dir */
2239 	name = kmem_alloc(MAXPATHLEN, KM_SLEEP);
2240 	ds = origin_ds;
2241 	/* CONSTCOND */
2242 	while (TRUE) {
2243 		dsl_dataset_t *prev;
2244 
2245 		/* move snap name entry */
2246 		dsl_dataset_name(ds, name);
2247 		VERIFY(0 == zap_remove(dp->dp_meta_objset,
2248 		    pa->snapnames_obj, ds->ds_snapname, tx));
2249 		VERIFY(0 == zap_add(dp->dp_meta_objset,
2250 		    hds->ds_phys->ds_snapnames_zapobj, ds->ds_snapname,
2251 		    8, 1, &ds->ds_object, tx));
2252 
2253 		/* change containing dsl_dir */
2254 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
2255 		ASSERT3U(ds->ds_phys->ds_dir_obj, ==, odd->dd_object);
2256 		ds->ds_phys->ds_dir_obj = dd->dd_object;
2257 		ASSERT3P(ds->ds_dir, ==, odd);
2258 		dsl_dir_close(ds->ds_dir, ds);
2259 		VERIFY(0 == dsl_dir_open_obj(dp, dd->dd_object,
2260 		    NULL, ds, &ds->ds_dir));
2261 
2262 		ASSERT3U(dsl_prop_numcb(ds), ==, 0);
2263 
2264 		if (ds->ds_phys->ds_prev_snap_obj == 0)
2265 			break;
2266 
2267 		VERIFY(0 == dsl_dataset_open_obj(dp,
2268 		    ds->ds_phys->ds_prev_snap_obj, NULL, DS_MODE_EXCLUSIVE,
2269 		    FTAG, &prev));
2270 
2271 		if (prev->ds_phys->ds_next_snap_obj != ds->ds_object) {
2272 			dsl_dataset_close(prev, DS_MODE_EXCLUSIVE, FTAG);
2273 			break;
2274 		}
2275 		if (ds != origin_ds)
2276 			dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
2277 		ds = prev;
2278 	}
2279 	if (ds != origin_ds)
2280 		dsl_dataset_close(ds, DS_MODE_EXCLUSIVE, FTAG);
2281 
2282 	/* change origin's next snap */
2283 	dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
2284 	origin_ds->ds_phys->ds_next_snap_obj = pa->newnext_obj;
2285 
2286 	/* change origin */
2287 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
2288 	ASSERT3U(dd->dd_phys->dd_origin_obj, ==, origin_ds->ds_object);
2289 	dd->dd_phys->dd_origin_obj = odd->dd_phys->dd_origin_obj;
2290 	dmu_buf_will_dirty(odd->dd_dbuf, tx);
2291 	odd->dd_phys->dd_origin_obj = origin_ds->ds_object;
2292 
2293 	/* change space accounting */
2294 	dsl_dir_diduse_space(odd, -pa->used, -pa->comp, -pa->uncomp, tx);
2295 	dsl_dir_diduse_space(dd, pa->used, pa->comp, pa->uncomp, tx);
2296 	origin_ds->ds_phys->ds_unique_bytes = pa->unique;
2297 
2298 	/* log history record */
2299 	spa_history_internal_log(LOG_DS_PROMOTE, dd->dd_pool->dp_spa, tx,
2300 	    cr, "dataset = %llu", ds->ds_object);
2301 
2302 	dsl_dir_close(odd, FTAG);
2303 	dsl_dataset_close(origin_ds, DS_MODE_EXCLUSIVE, FTAG);
2304 	kmem_free(name, MAXPATHLEN);
2305 }
2306 
2307 int
2308 dsl_dataset_promote(const char *name)
2309 {
2310 	dsl_dataset_t *ds;
2311 	int err;
2312 	dmu_object_info_t doi;
2313 	struct promotearg pa;
2314 
2315 	err = dsl_dataset_open(name, DS_MODE_NONE, FTAG, &ds);
2316 	if (err)
2317 		return (err);
2318 
2319 	err = dmu_object_info(ds->ds_dir->dd_pool->dp_meta_objset,
2320 	    ds->ds_phys->ds_snapnames_zapobj, &doi);
2321 	if (err) {
2322 		dsl_dataset_close(ds, DS_MODE_NONE, FTAG);
2323 		return (err);
2324 	}
2325 
2326 	/*
2327 	 * Add in 128x the snapnames zapobj size, since we will be moving
2328 	 * a bunch of snapnames to the promoted ds, and dirtying their
2329 	 * bonus buffers.
2330 	 */
2331 	err = dsl_sync_task_do(ds->ds_dir->dd_pool,
2332 	    dsl_dataset_promote_check,
2333 	    dsl_dataset_promote_sync, ds, &pa, 2 + 2 * doi.doi_physical_blks);
2334 	dsl_dataset_close(ds, DS_MODE_NONE, FTAG);
2335 	return (err);
2336 }
2337 
2338 struct cloneswaparg {
2339 	dsl_dataset_t *cds; /* clone dataset */
2340 	dsl_dataset_t *ohds; /* origin's head dataset */
2341 	boolean_t force;
2342 	int64_t unused_refres_delta; /* change in unconsumed refreservation */
2343 };
2344 
2345 /* ARGSUSED */
2346 static int
2347 dsl_dataset_clone_swap_check(void *arg1, void *arg2, dmu_tx_t *tx)
2348 {
2349 	struct cloneswaparg *csa = arg1;
2350 
2351 	/* they should both be heads */
2352 	if (dsl_dataset_is_snapshot(csa->cds) ||
2353 	    dsl_dataset_is_snapshot(csa->ohds))
2354 		return (EINVAL);
2355 
2356 	/* the branch point should be just before them */
2357 	if (csa->cds->ds_prev != csa->ohds->ds_prev)
2358 		return (EINVAL);
2359 
2360 	/* cds should be the clone */
2361 	if (csa->cds->ds_prev->ds_phys->ds_next_snap_obj !=
2362 	    csa->ohds->ds_object)
2363 		return (EINVAL);
2364 
2365 	/* the clone should be a child of the origin */
2366 	if (csa->cds->ds_dir->dd_parent != csa->ohds->ds_dir)
2367 		return (EINVAL);
2368 
2369 	/* ohds shouldn't be modified unless 'force' */
2370 	if (!csa->force && dsl_dataset_modified_since_lastsnap(csa->ohds))
2371 		return (ETXTBSY);
2372 
2373 	/* adjust amount of any unconsumed refreservation */
2374 	csa->unused_refres_delta =
2375 	    (int64_t)MIN(csa->ohds->ds_reserved,
2376 	    csa->ohds->ds_phys->ds_unique_bytes) -
2377 	    (int64_t)MIN(csa->ohds->ds_reserved,
2378 	    csa->cds->ds_phys->ds_unique_bytes);
2379 
2380 	if (csa->unused_refres_delta > 0 &&
2381 	    csa->unused_refres_delta >
2382 	    dsl_dir_space_available(csa->ohds->ds_dir, NULL, 0, TRUE))
2383 		return (ENOSPC);
2384 
2385 	return (0);
2386 }
2387 
2388 /* ARGSUSED */
2389 static void
2390 dsl_dataset_clone_swap_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
2391 {
2392 	struct cloneswaparg *csa = arg1;
2393 	dsl_pool_t *dp = csa->cds->ds_dir->dd_pool;
2394 	uint64_t itor = 0;
2395 	blkptr_t bp;
2396 	uint64_t unique = 0;
2397 	int err;
2398 
2399 	ASSERT(csa->cds->ds_reserved == 0);
2400 	ASSERT(csa->cds->ds_quota == csa->ohds->ds_quota);
2401 
2402 	dmu_buf_will_dirty(csa->cds->ds_dbuf, tx);
2403 	dmu_buf_will_dirty(csa->ohds->ds_dbuf, tx);
2404 	dmu_buf_will_dirty(csa->cds->ds_prev->ds_dbuf, tx);
2405 
2406 	if (csa->cds->ds_user_ptr != NULL) {
2407 		csa->cds->ds_user_evict_func(csa->cds, csa->cds->ds_user_ptr);
2408 		csa->cds->ds_user_ptr = NULL;
2409 	}
2410 
2411 	if (csa->ohds->ds_user_ptr != NULL) {
2412 		csa->ohds->ds_user_evict_func(csa->ohds,
2413 		    csa->ohds->ds_user_ptr);
2414 		csa->ohds->ds_user_ptr = NULL;
2415 	}
2416 
2417 	/* compute unique space */
2418 	while ((err = bplist_iterate(&csa->cds->ds_deadlist,
2419 	    &itor, &bp)) == 0) {
2420 		if (bp.blk_birth > csa->cds->ds_prev->ds_phys->ds_prev_snap_txg)
2421 			unique += bp_get_dasize(dp->dp_spa, &bp);
2422 	}
2423 	VERIFY(err == ENOENT);
2424 
2425 	/* reset origin's unique bytes */
2426 	csa->cds->ds_prev->ds_phys->ds_unique_bytes = unique;
2427 
2428 	/* swap blkptrs */
2429 	{
2430 		blkptr_t tmp;
2431 		tmp = csa->ohds->ds_phys->ds_bp;
2432 		csa->ohds->ds_phys->ds_bp = csa->cds->ds_phys->ds_bp;
2433 		csa->cds->ds_phys->ds_bp = tmp;
2434 	}
2435 
2436 	/* set dd_*_bytes */
2437 	{
2438 		int64_t dused, dcomp, duncomp;
2439 		uint64_t cdl_used, cdl_comp, cdl_uncomp;
2440 		uint64_t odl_used, odl_comp, odl_uncomp;
2441 
2442 		VERIFY(0 == bplist_space(&csa->cds->ds_deadlist, &cdl_used,
2443 		    &cdl_comp, &cdl_uncomp));
2444 		VERIFY(0 == bplist_space(&csa->ohds->ds_deadlist, &odl_used,
2445 		    &odl_comp, &odl_uncomp));
2446 		dused = csa->cds->ds_phys->ds_used_bytes + cdl_used -
2447 		    (csa->ohds->ds_phys->ds_used_bytes + odl_used);
2448 		dcomp = csa->cds->ds_phys->ds_compressed_bytes + cdl_comp -
2449 		    (csa->ohds->ds_phys->ds_compressed_bytes + odl_comp);
2450 		duncomp = csa->cds->ds_phys->ds_uncompressed_bytes +
2451 		    cdl_uncomp -
2452 		    (csa->ohds->ds_phys->ds_uncompressed_bytes + odl_uncomp);
2453 
2454 		dsl_dir_diduse_space(csa->ohds->ds_dir,
2455 		    dused, dcomp, duncomp, tx);
2456 		dsl_dir_diduse_space(csa->cds->ds_dir,
2457 		    -dused, -dcomp, -duncomp, tx);
2458 	}
2459 
2460 #define	SWITCH64(x, y) \
2461 	{ \
2462 		uint64_t __tmp = (x); \
2463 		(x) = (y); \
2464 		(y) = __tmp; \
2465 	}
2466 
2467 	/* swap ds_*_bytes */
2468 	SWITCH64(csa->ohds->ds_phys->ds_used_bytes,
2469 	    csa->cds->ds_phys->ds_used_bytes);
2470 	SWITCH64(csa->ohds->ds_phys->ds_compressed_bytes,
2471 	    csa->cds->ds_phys->ds_compressed_bytes);
2472 	SWITCH64(csa->ohds->ds_phys->ds_uncompressed_bytes,
2473 	    csa->cds->ds_phys->ds_uncompressed_bytes);
2474 	SWITCH64(csa->ohds->ds_phys->ds_unique_bytes,
2475 	    csa->cds->ds_phys->ds_unique_bytes);
2476 
2477 	/* apply any parent delta for change in unconsumed refreservation */
2478 	dsl_dir_diduse_space(csa->ohds->ds_dir, csa->unused_refres_delta,
2479 	    0, 0, tx);
2480 
2481 	/* swap deadlists */
2482 	bplist_close(&csa->cds->ds_deadlist);
2483 	bplist_close(&csa->ohds->ds_deadlist);
2484 	SWITCH64(csa->ohds->ds_phys->ds_deadlist_obj,
2485 	    csa->cds->ds_phys->ds_deadlist_obj);
2486 	VERIFY(0 == bplist_open(&csa->cds->ds_deadlist, dp->dp_meta_objset,
2487 	    csa->cds->ds_phys->ds_deadlist_obj));
2488 	VERIFY(0 == bplist_open(&csa->ohds->ds_deadlist, dp->dp_meta_objset,
2489 	    csa->ohds->ds_phys->ds_deadlist_obj));
2490 }
2491 
2492 /*
2493  * Swap 'clone' with its origin head file system.
2494  */
2495 int
2496 dsl_dataset_clone_swap(dsl_dataset_t *clone, dsl_dataset_t *origin_head,
2497     boolean_t force)
2498 {
2499 	struct cloneswaparg csa;
2500 
2501 	ASSERT(clone->ds_open_refcount == DS_REF_MAX);
2502 	ASSERT(origin_head->ds_open_refcount == DS_REF_MAX);
2503 
2504 	csa.cds = clone;
2505 	csa.ohds = origin_head;
2506 	csa.force = force;
2507 	return (dsl_sync_task_do(clone->ds_dir->dd_pool,
2508 	    dsl_dataset_clone_swap_check,
2509 	    dsl_dataset_clone_swap_sync, &csa, NULL, 9));
2510 }
2511 
2512 /*
2513  * Given a pool name and a dataset object number in that pool,
2514  * return the name of that dataset.
2515  */
2516 int
2517 dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf)
2518 {
2519 	spa_t *spa;
2520 	dsl_pool_t *dp;
2521 	dsl_dataset_t *ds = NULL;
2522 	int error;
2523 
2524 	if ((error = spa_open(pname, &spa, FTAG)) != 0)
2525 		return (error);
2526 	dp = spa_get_dsl(spa);
2527 	rw_enter(&dp->dp_config_rwlock, RW_READER);
2528 	if ((error = dsl_dataset_open_obj(dp, obj,
2529 	    NULL, DS_MODE_NONE, FTAG, &ds)) != 0) {
2530 		rw_exit(&dp->dp_config_rwlock);
2531 		spa_close(spa, FTAG);
2532 		return (error);
2533 	}
2534 	dsl_dataset_name(ds, buf);
2535 	dsl_dataset_close(ds, DS_MODE_NONE, FTAG);
2536 	rw_exit(&dp->dp_config_rwlock);
2537 	spa_close(spa, FTAG);
2538 
2539 	return (0);
2540 }
2541 
2542 int
2543 dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota,
2544     uint64_t asize, uint64_t inflight, uint64_t *used)
2545 {
2546 	int error = 0;
2547 
2548 	ASSERT3S(asize, >, 0);
2549 
2550 	mutex_enter(&ds->ds_lock);
2551 	/*
2552 	 * Make a space adjustment for reserved bytes.
2553 	 */
2554 	if (ds->ds_reserved > ds->ds_phys->ds_unique_bytes) {
2555 		ASSERT3U(*used, >=,
2556 		    ds->ds_reserved - ds->ds_phys->ds_unique_bytes);
2557 		*used -= (ds->ds_reserved - ds->ds_phys->ds_unique_bytes);
2558 	}
2559 
2560 	if (!check_quota || ds->ds_quota == 0) {
2561 		mutex_exit(&ds->ds_lock);
2562 		return (0);
2563 	}
2564 	/*
2565 	 * If they are requesting more space, and our current estimate
2566 	 * is over quota, they get to try again unless the actual
2567 	 * on-disk is over quota and there are no pending changes (which
2568 	 * may free up space for us).
2569 	 */
2570 	if (ds->ds_phys->ds_used_bytes + inflight >= ds->ds_quota) {
2571 		if (inflight > 0 || ds->ds_phys->ds_used_bytes < ds->ds_quota)
2572 			error = ERESTART;
2573 		else
2574 			error = EDQUOT;
2575 	}
2576 	mutex_exit(&ds->ds_lock);
2577 
2578 	return (error);
2579 }
2580 
2581 /* ARGSUSED */
2582 static int
2583 dsl_dataset_set_quota_check(void *arg1, void *arg2, dmu_tx_t *tx)
2584 {
2585 	dsl_dataset_t *ds = arg1;
2586 	uint64_t *quotap = arg2;
2587 	uint64_t new_quota = *quotap;
2588 
2589 	if (spa_version(ds->ds_dir->dd_pool->dp_spa) < SPA_VERSION_REFQUOTA)
2590 		return (ENOTSUP);
2591 
2592 	if (new_quota == 0)
2593 		return (0);
2594 
2595 	if (new_quota < ds->ds_phys->ds_used_bytes ||
2596 	    new_quota < ds->ds_reserved)
2597 		return (ENOSPC);
2598 
2599 	return (0);
2600 }
2601 
2602 /* ARGSUSED */
2603 void
2604 dsl_dataset_set_quota_sync(void *arg1, void *arg2, cred_t *cr, dmu_tx_t *tx)
2605 {
2606 	dsl_dataset_t *ds = arg1;
2607 	uint64_t *quotap = arg2;
2608 	uint64_t new_quota = *quotap;
2609 
2610 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
2611 
2612 	mutex_enter(&ds->ds_lock);
2613 	ds->ds_quota = new_quota;
2614 	mutex_exit(&ds->ds_lock);
2615 
2616 	dsl_prop_set_uint64_sync(ds->ds_dir, "refquota", new_quota, cr, tx);
2617 
2618 	spa_history_internal_log(LOG_DS_REFQUOTA, ds->ds_dir->dd_pool->dp_spa,
2619 	    tx, cr, "%lld dataset = %llu ",
2620 	    (longlong_t)new_quota, ds->ds_dir->dd_phys->dd_head_dataset_obj);
2621 }
2622 
2623 int
2624 dsl_dataset_set_quota(const char *dsname, uint64_t quota)
2625 {
2626 	dsl_dataset_t *ds;
2627 	int err;
2628 
2629 	err = dsl_dataset_open(dsname, DS_MODE_STANDARD, FTAG, &ds);
2630 	if (err)
2631 		return (err);
2632 
2633 	if (quota != ds->ds_quota) {
2634 		/*
2635 		 * If someone removes a file, then tries to set the quota, we
2636 		 * want to make sure the file freeing takes effect.
2637 		 */
2638 		txg_wait_open(ds->ds_dir->dd_pool, 0);
2639 
2640 		err = dsl_sync_task_do(ds->ds_dir->dd_pool,
2641 		    dsl_dataset_set_quota_check, dsl_dataset_set_quota_sync,
2642 		    ds, &quota, 0);
2643 	}
2644 	dsl_dataset_close(ds, DS_MODE_STANDARD, FTAG);
2645 	return (err);
2646 }
2647 
2648 static int
2649 dsl_dataset_set_reservation_check(void *arg1, void *arg2, dmu_tx_t *tx)
2650 {
2651 	dsl_dataset_t *ds = arg1;
2652 	uint64_t *reservationp = arg2;
2653 	uint64_t new_reservation = *reservationp;
2654 	int64_t delta;
2655 	uint64_t unique;
2656 
2657 	if (new_reservation > INT64_MAX)
2658 		return (EOVERFLOW);
2659 
2660 	if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
2661 	    SPA_VERSION_REFRESERVATION)
2662 		return (ENOTSUP);
2663 
2664 	if (dsl_dataset_is_snapshot(ds))
2665 		return (EINVAL);
2666 
2667 	/*
2668 	 * If we are doing the preliminary check in open context, the
2669 	 * space estimates may be inaccurate.
2670 	 */
2671 	if (!dmu_tx_is_syncing(tx))
2672 		return (0);
2673 
2674 	mutex_enter(&ds->ds_lock);
2675 	unique = dsl_dataset_unique(ds);
2676 	delta = MAX(unique, new_reservation) - MAX(unique, ds->ds_reserved);
2677 	mutex_exit(&ds->ds_lock);
2678 
2679 	if (delta > 0 &&
2680 	    delta > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE))
2681 		return (ENOSPC);
2682 	if (delta > 0 && ds->ds_quota > 0 &&
2683 	    new_reservation > ds->ds_quota)
2684 		return (ENOSPC);
2685 
2686 	return (0);
2687 }
2688 
2689 /* ARGSUSED */
2690 static void
2691 dsl_dataset_set_reservation_sync(void *arg1, void *arg2, cred_t *cr,
2692     dmu_tx_t *tx)
2693 {
2694 	dsl_dataset_t *ds = arg1;
2695 	uint64_t *reservationp = arg2;
2696 	uint64_t new_reservation = *reservationp;
2697 	uint64_t unique;
2698 	int64_t delta;
2699 
2700 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
2701 
2702 	mutex_enter(&ds->ds_lock);
2703 	unique = dsl_dataset_unique(ds);
2704 	delta = MAX(0, (int64_t)(new_reservation - unique)) -
2705 	    MAX(0, (int64_t)(ds->ds_reserved - unique));
2706 	ds->ds_reserved = new_reservation;
2707 	mutex_exit(&ds->ds_lock);
2708 
2709 	dsl_prop_set_uint64_sync(ds->ds_dir, "refreservation",
2710 	    new_reservation, cr, tx);
2711 
2712 	dsl_dir_diduse_space(ds->ds_dir, delta, 0, 0, tx);
2713 
2714 	spa_history_internal_log(LOG_DS_REFRESERV,
2715 	    ds->ds_dir->dd_pool->dp_spa, tx, cr, "%lld dataset = %llu",
2716 	    (longlong_t)new_reservation,
2717 	    ds->ds_dir->dd_phys->dd_head_dataset_obj);
2718 }
2719 
2720 int
2721 dsl_dataset_set_reservation(const char *dsname, uint64_t reservation)
2722 {
2723 	dsl_dataset_t *ds;
2724 	int err;
2725 
2726 	err = dsl_dataset_open(dsname, DS_MODE_STANDARD, FTAG, &ds);
2727 	if (err)
2728 		return (err);
2729 
2730 	err = dsl_sync_task_do(ds->ds_dir->dd_pool,
2731 	    dsl_dataset_set_reservation_check,
2732 	    dsl_dataset_set_reservation_sync, ds, &reservation, 0);
2733 	dsl_dataset_close(ds, DS_MODE_STANDARD, FTAG);
2734 	return (err);
2735 }
2736