xref: /illumos-gate/usr/src/uts/common/fs/zfs/dsl_dataset.c (revision edb901aab9c738b5eb15aa55933e82b0f2f9d9a2)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2011, 2016 by Delphix. All rights reserved.
24  * Copyright (c) 2014, Joyent, Inc. All rights reserved.
25  * Copyright (c) 2014 RackTop Systems.
26  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
27  * Copyright (c) 2014 Integros [integros.com]
28  * Copyright 2016, OmniTI Computer Consulting, Inc. All rights reserved.
29  */
30 
31 #include <sys/dmu_objset.h>
32 #include <sys/dsl_dataset.h>
33 #include <sys/dsl_dir.h>
34 #include <sys/dsl_prop.h>
35 #include <sys/dsl_synctask.h>
36 #include <sys/dmu_traverse.h>
37 #include <sys/dmu_impl.h>
38 #include <sys/dmu_tx.h>
39 #include <sys/arc.h>
40 #include <sys/zio.h>
41 #include <sys/zap.h>
42 #include <sys/zfeature.h>
43 #include <sys/unique.h>
44 #include <sys/zfs_context.h>
45 #include <sys/zfs_ioctl.h>
46 #include <sys/spa.h>
47 #include <sys/zfs_znode.h>
48 #include <sys/zfs_onexit.h>
49 #include <sys/zvol.h>
50 #include <sys/dsl_scan.h>
51 #include <sys/dsl_deadlist.h>
52 #include <sys/dsl_destroy.h>
53 #include <sys/dsl_userhold.h>
54 #include <sys/dsl_bookmark.h>
55 #include <sys/dmu_send.h>
56 #include <sys/zio_checksum.h>
57 #include <sys/zio_compress.h>
58 #include <zfs_fletcher.h>
59 
60 /*
61  * The SPA supports block sizes up to 16MB.  However, very large blocks
62  * can have an impact on i/o latency (e.g. tying up a spinning disk for
63  * ~300ms), and also potentially on the memory allocator.  Therefore,
64  * we do not allow the recordsize to be set larger than zfs_max_recordsize
65  * (default 1MB).  Larger blocks can be created by changing this tunable,
66  * and pools with larger blocks can always be imported and used, regardless
67  * of this setting.
68  */
69 int zfs_max_recordsize = 1 * 1024 * 1024;
70 
71 #define	SWITCH64(x, y) \
72 	{ \
73 		uint64_t __tmp = (x); \
74 		(x) = (y); \
75 		(y) = __tmp; \
76 	}
77 
78 #define	DS_REF_MAX	(1ULL << 62)
79 
80 extern inline dsl_dataset_phys_t *dsl_dataset_phys(dsl_dataset_t *ds);
81 
82 extern int spa_asize_inflation;
83 
84 /*
85  * Figure out how much of this delta should be propogated to the dsl_dir
86  * layer.  If there's a refreservation, that space has already been
87  * partially accounted for in our ancestors.
88  */
89 static int64_t
90 parent_delta(dsl_dataset_t *ds, int64_t delta)
91 {
92 	dsl_dataset_phys_t *ds_phys;
93 	uint64_t old_bytes, new_bytes;
94 
95 	if (ds->ds_reserved == 0)
96 		return (delta);
97 
98 	ds_phys = dsl_dataset_phys(ds);
99 	old_bytes = MAX(ds_phys->ds_unique_bytes, ds->ds_reserved);
100 	new_bytes = MAX(ds_phys->ds_unique_bytes + delta, ds->ds_reserved);
101 
102 	ASSERT3U(ABS((int64_t)(new_bytes - old_bytes)), <=, ABS(delta));
103 	return (new_bytes - old_bytes);
104 }
105 
106 void
107 dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
108 {
109 	int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
110 	int compressed = BP_GET_PSIZE(bp);
111 	int uncompressed = BP_GET_UCSIZE(bp);
112 	int64_t delta;
113 
114 	dprintf_bp(bp, "ds=%p", ds);
115 
116 	ASSERT(dmu_tx_is_syncing(tx));
117 	/* It could have been compressed away to nothing */
118 	if (BP_IS_HOLE(bp))
119 		return;
120 	ASSERT(BP_GET_TYPE(bp) != DMU_OT_NONE);
121 	ASSERT(DMU_OT_IS_VALID(BP_GET_TYPE(bp)));
122 	if (ds == NULL) {
123 		dsl_pool_mos_diduse_space(tx->tx_pool,
124 		    used, compressed, uncompressed);
125 		return;
126 	}
127 
128 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
129 	mutex_enter(&ds->ds_lock);
130 	delta = parent_delta(ds, used);
131 	dsl_dataset_phys(ds)->ds_referenced_bytes += used;
132 	dsl_dataset_phys(ds)->ds_compressed_bytes += compressed;
133 	dsl_dataset_phys(ds)->ds_uncompressed_bytes += uncompressed;
134 	dsl_dataset_phys(ds)->ds_unique_bytes += used;
135 
136 	if (BP_GET_LSIZE(bp) > SPA_OLD_MAXBLOCKSIZE) {
137 		ds->ds_feature_activation_needed[SPA_FEATURE_LARGE_BLOCKS] =
138 		    B_TRUE;
139 	}
140 
141 	spa_feature_t f = zio_checksum_to_feature(BP_GET_CHECKSUM(bp));
142 	if (f != SPA_FEATURE_NONE)
143 		ds->ds_feature_activation_needed[f] = B_TRUE;
144 
145 	mutex_exit(&ds->ds_lock);
146 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD, delta,
147 	    compressed, uncompressed, tx);
148 	dsl_dir_transfer_space(ds->ds_dir, used - delta,
149 	    DD_USED_REFRSRV, DD_USED_HEAD, tx);
150 }
151 
152 int
153 dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
154     boolean_t async)
155 {
156 	int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
157 	int compressed = BP_GET_PSIZE(bp);
158 	int uncompressed = BP_GET_UCSIZE(bp);
159 
160 	if (BP_IS_HOLE(bp))
161 		return (0);
162 
163 	ASSERT(dmu_tx_is_syncing(tx));
164 	ASSERT(bp->blk_birth <= tx->tx_txg);
165 
166 	if (ds == NULL) {
167 		dsl_free(tx->tx_pool, tx->tx_txg, bp);
168 		dsl_pool_mos_diduse_space(tx->tx_pool,
169 		    -used, -compressed, -uncompressed);
170 		return (used);
171 	}
172 	ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool);
173 
174 	ASSERT(!ds->ds_is_snapshot);
175 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
176 
177 	if (bp->blk_birth > dsl_dataset_phys(ds)->ds_prev_snap_txg) {
178 		int64_t delta;
179 
180 		dprintf_bp(bp, "freeing ds=%llu", ds->ds_object);
181 		dsl_free(tx->tx_pool, tx->tx_txg, bp);
182 
183 		mutex_enter(&ds->ds_lock);
184 		ASSERT(dsl_dataset_phys(ds)->ds_unique_bytes >= used ||
185 		    !DS_UNIQUE_IS_ACCURATE(ds));
186 		delta = parent_delta(ds, -used);
187 		dsl_dataset_phys(ds)->ds_unique_bytes -= used;
188 		mutex_exit(&ds->ds_lock);
189 		dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
190 		    delta, -compressed, -uncompressed, tx);
191 		dsl_dir_transfer_space(ds->ds_dir, -used - delta,
192 		    DD_USED_REFRSRV, DD_USED_HEAD, tx);
193 	} else {
194 		dprintf_bp(bp, "putting on dead list: %s", "");
195 		if (async) {
196 			/*
197 			 * We are here as part of zio's write done callback,
198 			 * which means we're a zio interrupt thread.  We can't
199 			 * call dsl_deadlist_insert() now because it may block
200 			 * waiting for I/O.  Instead, put bp on the deferred
201 			 * queue and let dsl_pool_sync() finish the job.
202 			 */
203 			bplist_append(&ds->ds_pending_deadlist, bp);
204 		} else {
205 			dsl_deadlist_insert(&ds->ds_deadlist, bp, tx);
206 		}
207 		ASSERT3U(ds->ds_prev->ds_object, ==,
208 		    dsl_dataset_phys(ds)->ds_prev_snap_obj);
209 		ASSERT(dsl_dataset_phys(ds->ds_prev)->ds_num_children > 0);
210 		/* if (bp->blk_birth > prev prev snap txg) prev unique += bs */
211 		if (dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
212 		    ds->ds_object && bp->blk_birth >
213 		    dsl_dataset_phys(ds->ds_prev)->ds_prev_snap_txg) {
214 			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
215 			mutex_enter(&ds->ds_prev->ds_lock);
216 			dsl_dataset_phys(ds->ds_prev)->ds_unique_bytes += used;
217 			mutex_exit(&ds->ds_prev->ds_lock);
218 		}
219 		if (bp->blk_birth > ds->ds_dir->dd_origin_txg) {
220 			dsl_dir_transfer_space(ds->ds_dir, used,
221 			    DD_USED_HEAD, DD_USED_SNAP, tx);
222 		}
223 	}
224 	mutex_enter(&ds->ds_lock);
225 	ASSERT3U(dsl_dataset_phys(ds)->ds_referenced_bytes, >=, used);
226 	dsl_dataset_phys(ds)->ds_referenced_bytes -= used;
227 	ASSERT3U(dsl_dataset_phys(ds)->ds_compressed_bytes, >=, compressed);
228 	dsl_dataset_phys(ds)->ds_compressed_bytes -= compressed;
229 	ASSERT3U(dsl_dataset_phys(ds)->ds_uncompressed_bytes, >=, uncompressed);
230 	dsl_dataset_phys(ds)->ds_uncompressed_bytes -= uncompressed;
231 	mutex_exit(&ds->ds_lock);
232 
233 	return (used);
234 }
235 
236 uint64_t
237 dsl_dataset_prev_snap_txg(dsl_dataset_t *ds)
238 {
239 	uint64_t trysnap = 0;
240 
241 	if (ds == NULL)
242 		return (0);
243 	/*
244 	 * The snapshot creation could fail, but that would cause an
245 	 * incorrect FALSE return, which would only result in an
246 	 * overestimation of the amount of space that an operation would
247 	 * consume, which is OK.
248 	 *
249 	 * There's also a small window where we could miss a pending
250 	 * snapshot, because we could set the sync task in the quiescing
251 	 * phase.  So this should only be used as a guess.
252 	 */
253 	if (ds->ds_trysnap_txg >
254 	    spa_last_synced_txg(ds->ds_dir->dd_pool->dp_spa))
255 		trysnap = ds->ds_trysnap_txg;
256 	return (MAX(dsl_dataset_phys(ds)->ds_prev_snap_txg, trysnap));
257 }
258 
259 boolean_t
260 dsl_dataset_block_freeable(dsl_dataset_t *ds, const blkptr_t *bp,
261     uint64_t blk_birth)
262 {
263 	if (blk_birth <= dsl_dataset_prev_snap_txg(ds) ||
264 	    (bp != NULL && BP_IS_HOLE(bp)))
265 		return (B_FALSE);
266 
267 	ddt_prefetch(dsl_dataset_get_spa(ds), bp);
268 
269 	return (B_TRUE);
270 }
271 
272 /*
273  * We have to release the fsid syncronously or we risk that a subsequent
274  * mount of the same dataset will fail to unique_insert the fsid.  This
275  * failure would manifest itself as the fsid of this dataset changing
276  * between mounts which makes NFS clients quite unhappy.
277  */
278 static void
279 dsl_dataset_evict_sync(void *dbu)
280 {
281 	dsl_dataset_t *ds = dbu;
282 
283 	ASSERT(ds->ds_owner == NULL);
284 
285 	unique_remove(ds->ds_fsid_guid);
286 }
287 
288 static void
289 dsl_dataset_evict_async(void *dbu)
290 {
291 	dsl_dataset_t *ds = dbu;
292 
293 	ASSERT(ds->ds_owner == NULL);
294 
295 	ds->ds_dbuf = NULL;
296 
297 	if (ds->ds_objset != NULL)
298 		dmu_objset_evict(ds->ds_objset);
299 
300 	if (ds->ds_prev) {
301 		dsl_dataset_rele(ds->ds_prev, ds);
302 		ds->ds_prev = NULL;
303 	}
304 
305 	bplist_destroy(&ds->ds_pending_deadlist);
306 	if (ds->ds_deadlist.dl_os != NULL)
307 		dsl_deadlist_close(&ds->ds_deadlist);
308 	if (ds->ds_dir)
309 		dsl_dir_async_rele(ds->ds_dir, ds);
310 
311 	ASSERT(!list_link_active(&ds->ds_synced_link));
312 
313 	list_destroy(&ds->ds_prop_cbs);
314 	mutex_destroy(&ds->ds_lock);
315 	mutex_destroy(&ds->ds_opening_lock);
316 	mutex_destroy(&ds->ds_sendstream_lock);
317 	refcount_destroy(&ds->ds_longholds);
318 	rrw_destroy(&ds->ds_bp_rwlock);
319 
320 	kmem_free(ds, sizeof (dsl_dataset_t));
321 }
322 
323 int
324 dsl_dataset_get_snapname(dsl_dataset_t *ds)
325 {
326 	dsl_dataset_phys_t *headphys;
327 	int err;
328 	dmu_buf_t *headdbuf;
329 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
330 	objset_t *mos = dp->dp_meta_objset;
331 
332 	if (ds->ds_snapname[0])
333 		return (0);
334 	if (dsl_dataset_phys(ds)->ds_next_snap_obj == 0)
335 		return (0);
336 
337 	err = dmu_bonus_hold(mos, dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj,
338 	    FTAG, &headdbuf);
339 	if (err != 0)
340 		return (err);
341 	headphys = headdbuf->db_data;
342 	err = zap_value_search(dp->dp_meta_objset,
343 	    headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
344 	dmu_buf_rele(headdbuf, FTAG);
345 	return (err);
346 }
347 
348 int
349 dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value)
350 {
351 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
352 	uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
353 	matchtype_t mt;
354 	int err;
355 
356 	if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
357 		mt = MT_FIRST;
358 	else
359 		mt = MT_EXACT;
360 
361 	err = zap_lookup_norm(mos, snapobj, name, 8, 1,
362 	    value, mt, NULL, 0, NULL);
363 	if (err == ENOTSUP && mt == MT_FIRST)
364 		err = zap_lookup(mos, snapobj, name, 8, 1, value);
365 	return (err);
366 }
367 
368 int
369 dsl_dataset_snap_remove(dsl_dataset_t *ds, const char *name, dmu_tx_t *tx,
370     boolean_t adj_cnt)
371 {
372 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
373 	uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
374 	matchtype_t mt;
375 	int err;
376 
377 	dsl_dir_snap_cmtime_update(ds->ds_dir);
378 
379 	if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
380 		mt = MT_FIRST;
381 	else
382 		mt = MT_EXACT;
383 
384 	err = zap_remove_norm(mos, snapobj, name, mt, tx);
385 	if (err == ENOTSUP && mt == MT_FIRST)
386 		err = zap_remove(mos, snapobj, name, tx);
387 
388 	if (err == 0 && adj_cnt)
389 		dsl_fs_ss_count_adjust(ds->ds_dir, -1,
390 		    DD_FIELD_SNAPSHOT_COUNT, tx);
391 
392 	return (err);
393 }
394 
395 boolean_t
396 dsl_dataset_try_add_ref(dsl_pool_t *dp, dsl_dataset_t *ds, void *tag)
397 {
398 	dmu_buf_t *dbuf = ds->ds_dbuf;
399 	boolean_t result = B_FALSE;
400 
401 	if (dbuf != NULL && dmu_buf_try_add_ref(dbuf, dp->dp_meta_objset,
402 	    ds->ds_object, DMU_BONUS_BLKID, tag)) {
403 
404 		if (ds == dmu_buf_get_user(dbuf))
405 			result = B_TRUE;
406 		else
407 			dmu_buf_rele(dbuf, tag);
408 	}
409 
410 	return (result);
411 }
412 
413 int
414 dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
415     dsl_dataset_t **dsp)
416 {
417 	objset_t *mos = dp->dp_meta_objset;
418 	dmu_buf_t *dbuf;
419 	dsl_dataset_t *ds;
420 	int err;
421 	dmu_object_info_t doi;
422 
423 	ASSERT(dsl_pool_config_held(dp));
424 
425 	err = dmu_bonus_hold(mos, dsobj, tag, &dbuf);
426 	if (err != 0)
427 		return (err);
428 
429 	/* Make sure dsobj has the correct object type. */
430 	dmu_object_info_from_db(dbuf, &doi);
431 	if (doi.doi_bonus_type != DMU_OT_DSL_DATASET) {
432 		dmu_buf_rele(dbuf, tag);
433 		return (SET_ERROR(EINVAL));
434 	}
435 
436 	ds = dmu_buf_get_user(dbuf);
437 	if (ds == NULL) {
438 		dsl_dataset_t *winner = NULL;
439 
440 		ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP);
441 		ds->ds_dbuf = dbuf;
442 		ds->ds_object = dsobj;
443 		ds->ds_is_snapshot = dsl_dataset_phys(ds)->ds_num_children != 0;
444 
445 		mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
446 		mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
447 		mutex_init(&ds->ds_sendstream_lock, NULL, MUTEX_DEFAULT, NULL);
448 		rrw_init(&ds->ds_bp_rwlock, B_FALSE);
449 		refcount_create(&ds->ds_longholds);
450 
451 		bplist_create(&ds->ds_pending_deadlist);
452 		dsl_deadlist_open(&ds->ds_deadlist,
453 		    mos, dsl_dataset_phys(ds)->ds_deadlist_obj);
454 
455 		list_create(&ds->ds_sendstreams, sizeof (dmu_sendarg_t),
456 		    offsetof(dmu_sendarg_t, dsa_link));
457 
458 		list_create(&ds->ds_prop_cbs, sizeof (dsl_prop_cb_record_t),
459 		    offsetof(dsl_prop_cb_record_t, cbr_ds_node));
460 
461 		if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
462 			for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
463 				if (!(spa_feature_table[f].fi_flags &
464 				    ZFEATURE_FLAG_PER_DATASET))
465 					continue;
466 				err = zap_contains(mos, dsobj,
467 				    spa_feature_table[f].fi_guid);
468 				if (err == 0) {
469 					ds->ds_feature_inuse[f] = B_TRUE;
470 				} else {
471 					ASSERT3U(err, ==, ENOENT);
472 					err = 0;
473 				}
474 			}
475 		}
476 
477 		err = dsl_dir_hold_obj(dp,
478 		    dsl_dataset_phys(ds)->ds_dir_obj, NULL, ds, &ds->ds_dir);
479 		if (err != 0) {
480 			mutex_destroy(&ds->ds_lock);
481 			mutex_destroy(&ds->ds_opening_lock);
482 			mutex_destroy(&ds->ds_sendstream_lock);
483 			refcount_destroy(&ds->ds_longholds);
484 			bplist_destroy(&ds->ds_pending_deadlist);
485 			dsl_deadlist_close(&ds->ds_deadlist);
486 			kmem_free(ds, sizeof (dsl_dataset_t));
487 			dmu_buf_rele(dbuf, tag);
488 			return (err);
489 		}
490 
491 		if (!ds->ds_is_snapshot) {
492 			ds->ds_snapname[0] = '\0';
493 			if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
494 				err = dsl_dataset_hold_obj(dp,
495 				    dsl_dataset_phys(ds)->ds_prev_snap_obj,
496 				    ds, &ds->ds_prev);
497 			}
498 			if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
499 				int zaperr = zap_lookup(mos, ds->ds_object,
500 				    DS_FIELD_BOOKMARK_NAMES,
501 				    sizeof (ds->ds_bookmarks), 1,
502 				    &ds->ds_bookmarks);
503 				if (zaperr != ENOENT)
504 					VERIFY0(zaperr);
505 			}
506 		} else {
507 			if (zfs_flags & ZFS_DEBUG_SNAPNAMES)
508 				err = dsl_dataset_get_snapname(ds);
509 			if (err == 0 &&
510 			    dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
511 				err = zap_count(
512 				    ds->ds_dir->dd_pool->dp_meta_objset,
513 				    dsl_dataset_phys(ds)->ds_userrefs_obj,
514 				    &ds->ds_userrefs);
515 			}
516 		}
517 
518 		if (err == 0 && !ds->ds_is_snapshot) {
519 			err = dsl_prop_get_int_ds(ds,
520 			    zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
521 			    &ds->ds_reserved);
522 			if (err == 0) {
523 				err = dsl_prop_get_int_ds(ds,
524 				    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
525 				    &ds->ds_quota);
526 			}
527 		} else {
528 			ds->ds_reserved = ds->ds_quota = 0;
529 		}
530 
531 		dmu_buf_init_user(&ds->ds_dbu, dsl_dataset_evict_sync,
532 		    dsl_dataset_evict_async, &ds->ds_dbuf);
533 		if (err == 0)
534 			winner = dmu_buf_set_user_ie(dbuf, &ds->ds_dbu);
535 
536 		if (err != 0 || winner != NULL) {
537 			bplist_destroy(&ds->ds_pending_deadlist);
538 			dsl_deadlist_close(&ds->ds_deadlist);
539 			if (ds->ds_prev)
540 				dsl_dataset_rele(ds->ds_prev, ds);
541 			dsl_dir_rele(ds->ds_dir, ds);
542 			mutex_destroy(&ds->ds_lock);
543 			mutex_destroy(&ds->ds_opening_lock);
544 			mutex_destroy(&ds->ds_sendstream_lock);
545 			refcount_destroy(&ds->ds_longholds);
546 			kmem_free(ds, sizeof (dsl_dataset_t));
547 			if (err != 0) {
548 				dmu_buf_rele(dbuf, tag);
549 				return (err);
550 			}
551 			ds = winner;
552 		} else {
553 			ds->ds_fsid_guid =
554 			    unique_insert(dsl_dataset_phys(ds)->ds_fsid_guid);
555 			if (ds->ds_fsid_guid !=
556 			    dsl_dataset_phys(ds)->ds_fsid_guid) {
557 				zfs_dbgmsg("ds_fsid_guid changed from "
558 				    "%llx to %llx for pool %s dataset id %llu",
559 				    (long long)
560 				    dsl_dataset_phys(ds)->ds_fsid_guid,
561 				    (long long)ds->ds_fsid_guid,
562 				    spa_name(dp->dp_spa),
563 				    dsobj);
564 			}
565 		}
566 	}
567 	ASSERT3P(ds->ds_dbuf, ==, dbuf);
568 	ASSERT3P(dsl_dataset_phys(ds), ==, dbuf->db_data);
569 	ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0 ||
570 	    spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
571 	    dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
572 	*dsp = ds;
573 	return (0);
574 }
575 
576 int
577 dsl_dataset_hold(dsl_pool_t *dp, const char *name,
578     void *tag, dsl_dataset_t **dsp)
579 {
580 	dsl_dir_t *dd;
581 	const char *snapname;
582 	uint64_t obj;
583 	int err = 0;
584 	dsl_dataset_t *ds;
585 
586 	err = dsl_dir_hold(dp, name, FTAG, &dd, &snapname);
587 	if (err != 0)
588 		return (err);
589 
590 	ASSERT(dsl_pool_config_held(dp));
591 	obj = dsl_dir_phys(dd)->dd_head_dataset_obj;
592 	if (obj != 0)
593 		err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
594 	else
595 		err = SET_ERROR(ENOENT);
596 
597 	/* we may be looking for a snapshot */
598 	if (err == 0 && snapname != NULL) {
599 		dsl_dataset_t *snap_ds;
600 
601 		if (*snapname++ != '@') {
602 			dsl_dataset_rele(ds, tag);
603 			dsl_dir_rele(dd, FTAG);
604 			return (SET_ERROR(ENOENT));
605 		}
606 
607 		dprintf("looking for snapshot '%s'\n", snapname);
608 		err = dsl_dataset_snap_lookup(ds, snapname, &obj);
609 		if (err == 0)
610 			err = dsl_dataset_hold_obj(dp, obj, tag, &snap_ds);
611 		dsl_dataset_rele(ds, tag);
612 
613 		if (err == 0) {
614 			mutex_enter(&snap_ds->ds_lock);
615 			if (snap_ds->ds_snapname[0] == 0)
616 				(void) strlcpy(snap_ds->ds_snapname, snapname,
617 				    sizeof (snap_ds->ds_snapname));
618 			mutex_exit(&snap_ds->ds_lock);
619 			ds = snap_ds;
620 		}
621 	}
622 	if (err == 0)
623 		*dsp = ds;
624 	dsl_dir_rele(dd, FTAG);
625 	return (err);
626 }
627 
628 int
629 dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj,
630     void *tag, dsl_dataset_t **dsp)
631 {
632 	int err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp);
633 	if (err != 0)
634 		return (err);
635 	if (!dsl_dataset_tryown(*dsp, tag)) {
636 		dsl_dataset_rele(*dsp, tag);
637 		*dsp = NULL;
638 		return (SET_ERROR(EBUSY));
639 	}
640 	return (0);
641 }
642 
643 int
644 dsl_dataset_own(dsl_pool_t *dp, const char *name,
645     void *tag, dsl_dataset_t **dsp)
646 {
647 	int err = dsl_dataset_hold(dp, name, tag, dsp);
648 	if (err != 0)
649 		return (err);
650 	if (!dsl_dataset_tryown(*dsp, tag)) {
651 		dsl_dataset_rele(*dsp, tag);
652 		return (SET_ERROR(EBUSY));
653 	}
654 	return (0);
655 }
656 
657 /*
658  * See the comment above dsl_pool_hold() for details.  In summary, a long
659  * hold is used to prevent destruction of a dataset while the pool hold
660  * is dropped, allowing other concurrent operations (e.g. spa_sync()).
661  *
662  * The dataset and pool must be held when this function is called.  After it
663  * is called, the pool hold may be released while the dataset is still held
664  * and accessed.
665  */
666 void
667 dsl_dataset_long_hold(dsl_dataset_t *ds, void *tag)
668 {
669 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
670 	(void) refcount_add(&ds->ds_longholds, tag);
671 }
672 
673 void
674 dsl_dataset_long_rele(dsl_dataset_t *ds, void *tag)
675 {
676 	(void) refcount_remove(&ds->ds_longholds, tag);
677 }
678 
679 /* Return B_TRUE if there are any long holds on this dataset. */
680 boolean_t
681 dsl_dataset_long_held(dsl_dataset_t *ds)
682 {
683 	return (!refcount_is_zero(&ds->ds_longholds));
684 }
685 
686 void
687 dsl_dataset_name(dsl_dataset_t *ds, char *name)
688 {
689 	if (ds == NULL) {
690 		(void) strcpy(name, "mos");
691 	} else {
692 		dsl_dir_name(ds->ds_dir, name);
693 		VERIFY0(dsl_dataset_get_snapname(ds));
694 		if (ds->ds_snapname[0]) {
695 			VERIFY3U(strlcat(name, "@", ZFS_MAX_DATASET_NAME_LEN),
696 			    <, ZFS_MAX_DATASET_NAME_LEN);
697 			/*
698 			 * We use a "recursive" mutex so that we
699 			 * can call dprintf_ds() with ds_lock held.
700 			 */
701 			if (!MUTEX_HELD(&ds->ds_lock)) {
702 				mutex_enter(&ds->ds_lock);
703 				VERIFY3U(strlcat(name, ds->ds_snapname,
704 				    ZFS_MAX_DATASET_NAME_LEN), <,
705 				    ZFS_MAX_DATASET_NAME_LEN);
706 				mutex_exit(&ds->ds_lock);
707 			} else {
708 				VERIFY3U(strlcat(name, ds->ds_snapname,
709 				    ZFS_MAX_DATASET_NAME_LEN), <,
710 				    ZFS_MAX_DATASET_NAME_LEN);
711 			}
712 		}
713 	}
714 }
715 
716 int
717 dsl_dataset_namelen(dsl_dataset_t *ds)
718 {
719 	VERIFY0(dsl_dataset_get_snapname(ds));
720 	mutex_enter(&ds->ds_lock);
721 	int len = dsl_dir_namelen(ds->ds_dir) + 1 + strlen(ds->ds_snapname);
722 	mutex_exit(&ds->ds_lock);
723 	return (len);
724 }
725 
726 void
727 dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
728 {
729 	dmu_buf_rele(ds->ds_dbuf, tag);
730 }
731 
732 void
733 dsl_dataset_disown(dsl_dataset_t *ds, void *tag)
734 {
735 	ASSERT3P(ds->ds_owner, ==, tag);
736 	ASSERT(ds->ds_dbuf != NULL);
737 
738 	mutex_enter(&ds->ds_lock);
739 	ds->ds_owner = NULL;
740 	mutex_exit(&ds->ds_lock);
741 	dsl_dataset_long_rele(ds, tag);
742 	dsl_dataset_rele(ds, tag);
743 }
744 
745 boolean_t
746 dsl_dataset_tryown(dsl_dataset_t *ds, void *tag)
747 {
748 	boolean_t gotit = FALSE;
749 
750 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
751 	mutex_enter(&ds->ds_lock);
752 	if (ds->ds_owner == NULL && !DS_IS_INCONSISTENT(ds)) {
753 		ds->ds_owner = tag;
754 		dsl_dataset_long_hold(ds, tag);
755 		gotit = TRUE;
756 	}
757 	mutex_exit(&ds->ds_lock);
758 	return (gotit);
759 }
760 
761 boolean_t
762 dsl_dataset_has_owner(dsl_dataset_t *ds)
763 {
764 	boolean_t rv;
765 	mutex_enter(&ds->ds_lock);
766 	rv = (ds->ds_owner != NULL);
767 	mutex_exit(&ds->ds_lock);
768 	return (rv);
769 }
770 
771 static void
772 dsl_dataset_activate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
773 {
774 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
775 	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
776 	uint64_t zero = 0;
777 
778 	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
779 
780 	spa_feature_incr(spa, f, tx);
781 	dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
782 
783 	VERIFY0(zap_add(mos, dsobj, spa_feature_table[f].fi_guid,
784 	    sizeof (zero), 1, &zero, tx));
785 }
786 
787 void
788 dsl_dataset_deactivate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
789 {
790 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
791 	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
792 
793 	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
794 
795 	VERIFY0(zap_remove(mos, dsobj, spa_feature_table[f].fi_guid, tx));
796 	spa_feature_decr(spa, f, tx);
797 }
798 
799 uint64_t
800 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
801     uint64_t flags, dmu_tx_t *tx)
802 {
803 	dsl_pool_t *dp = dd->dd_pool;
804 	dmu_buf_t *dbuf;
805 	dsl_dataset_phys_t *dsphys;
806 	uint64_t dsobj;
807 	objset_t *mos = dp->dp_meta_objset;
808 
809 	if (origin == NULL)
810 		origin = dp->dp_origin_snap;
811 
812 	ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
813 	ASSERT(origin == NULL || dsl_dataset_phys(origin)->ds_num_children > 0);
814 	ASSERT(dmu_tx_is_syncing(tx));
815 	ASSERT(dsl_dir_phys(dd)->dd_head_dataset_obj == 0);
816 
817 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
818 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
819 	VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
820 	dmu_buf_will_dirty(dbuf, tx);
821 	dsphys = dbuf->db_data;
822 	bzero(dsphys, sizeof (dsl_dataset_phys_t));
823 	dsphys->ds_dir_obj = dd->dd_object;
824 	dsphys->ds_flags = flags;
825 	dsphys->ds_fsid_guid = unique_create();
826 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
827 	    sizeof (dsphys->ds_guid));
828 	dsphys->ds_snapnames_zapobj =
829 	    zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP,
830 	    DMU_OT_NONE, 0, tx);
831 	dsphys->ds_creation_time = gethrestime_sec();
832 	dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg;
833 
834 	if (origin == NULL) {
835 		dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx);
836 	} else {
837 		dsl_dataset_t *ohds; /* head of the origin snapshot */
838 
839 		dsphys->ds_prev_snap_obj = origin->ds_object;
840 		dsphys->ds_prev_snap_txg =
841 		    dsl_dataset_phys(origin)->ds_creation_txg;
842 		dsphys->ds_referenced_bytes =
843 		    dsl_dataset_phys(origin)->ds_referenced_bytes;
844 		dsphys->ds_compressed_bytes =
845 		    dsl_dataset_phys(origin)->ds_compressed_bytes;
846 		dsphys->ds_uncompressed_bytes =
847 		    dsl_dataset_phys(origin)->ds_uncompressed_bytes;
848 		rrw_enter(&origin->ds_bp_rwlock, RW_READER, FTAG);
849 		dsphys->ds_bp = dsl_dataset_phys(origin)->ds_bp;
850 		rrw_exit(&origin->ds_bp_rwlock, FTAG);
851 
852 		/*
853 		 * Inherit flags that describe the dataset's contents
854 		 * (INCONSISTENT) or properties (Case Insensitive).
855 		 */
856 		dsphys->ds_flags |= dsl_dataset_phys(origin)->ds_flags &
857 		    (DS_FLAG_INCONSISTENT | DS_FLAG_CI_DATASET);
858 
859 		for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
860 			if (origin->ds_feature_inuse[f])
861 				dsl_dataset_activate_feature(dsobj, f, tx);
862 		}
863 
864 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
865 		dsl_dataset_phys(origin)->ds_num_children++;
866 
867 		VERIFY0(dsl_dataset_hold_obj(dp,
868 		    dsl_dir_phys(origin->ds_dir)->dd_head_dataset_obj,
869 		    FTAG, &ohds));
870 		dsphys->ds_deadlist_obj = dsl_deadlist_clone(&ohds->ds_deadlist,
871 		    dsphys->ds_prev_snap_txg, dsphys->ds_prev_snap_obj, tx);
872 		dsl_dataset_rele(ohds, FTAG);
873 
874 		if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) {
875 			if (dsl_dataset_phys(origin)->ds_next_clones_obj == 0) {
876 				dsl_dataset_phys(origin)->ds_next_clones_obj =
877 				    zap_create(mos,
878 				    DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
879 			}
880 			VERIFY0(zap_add_int(mos,
881 			    dsl_dataset_phys(origin)->ds_next_clones_obj,
882 			    dsobj, tx));
883 		}
884 
885 		dmu_buf_will_dirty(dd->dd_dbuf, tx);
886 		dsl_dir_phys(dd)->dd_origin_obj = origin->ds_object;
887 		if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
888 			if (dsl_dir_phys(origin->ds_dir)->dd_clones == 0) {
889 				dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
890 				dsl_dir_phys(origin->ds_dir)->dd_clones =
891 				    zap_create(mos,
892 				    DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
893 			}
894 			VERIFY0(zap_add_int(mos,
895 			    dsl_dir_phys(origin->ds_dir)->dd_clones,
896 			    dsobj, tx));
897 		}
898 	}
899 
900 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
901 		dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
902 
903 	dmu_buf_rele(dbuf, FTAG);
904 
905 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
906 	dsl_dir_phys(dd)->dd_head_dataset_obj = dsobj;
907 
908 	return (dsobj);
909 }
910 
911 static void
912 dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
913 {
914 	objset_t *os;
915 
916 	VERIFY0(dmu_objset_from_ds(ds, &os));
917 	bzero(&os->os_zil_header, sizeof (os->os_zil_header));
918 	dsl_dataset_dirty(ds, tx);
919 }
920 
921 uint64_t
922 dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
923     dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx)
924 {
925 	dsl_pool_t *dp = pdd->dd_pool;
926 	uint64_t dsobj, ddobj;
927 	dsl_dir_t *dd;
928 
929 	ASSERT(dmu_tx_is_syncing(tx));
930 	ASSERT(lastname[0] != '@');
931 
932 	ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
933 	VERIFY0(dsl_dir_hold_obj(dp, ddobj, lastname, FTAG, &dd));
934 
935 	dsobj = dsl_dataset_create_sync_dd(dd, origin,
936 	    flags & ~DS_CREATE_FLAG_NODIRTY, tx);
937 
938 	dsl_deleg_set_create_perms(dd, tx, cr);
939 
940 	/*
941 	 * Since we're creating a new node we know it's a leaf, so we can
942 	 * initialize the counts if the limit feature is active.
943 	 */
944 	if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT)) {
945 		uint64_t cnt = 0;
946 		objset_t *os = dd->dd_pool->dp_meta_objset;
947 
948 		dsl_dir_zapify(dd, tx);
949 		VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_FILESYSTEM_COUNT,
950 		    sizeof (cnt), 1, &cnt, tx));
951 		VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_SNAPSHOT_COUNT,
952 		    sizeof (cnt), 1, &cnt, tx));
953 	}
954 
955 	dsl_dir_rele(dd, FTAG);
956 
957 	/*
958 	 * If we are creating a clone, make sure we zero out any stale
959 	 * data from the origin snapshots zil header.
960 	 */
961 	if (origin != NULL && !(flags & DS_CREATE_FLAG_NODIRTY)) {
962 		dsl_dataset_t *ds;
963 
964 		VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
965 		dsl_dataset_zero_zil(ds, tx);
966 		dsl_dataset_rele(ds, FTAG);
967 	}
968 
969 	return (dsobj);
970 }
971 
972 /*
973  * The unique space in the head dataset can be calculated by subtracting
974  * the space used in the most recent snapshot, that is still being used
975  * in this file system, from the space currently in use.  To figure out
976  * the space in the most recent snapshot still in use, we need to take
977  * the total space used in the snapshot and subtract out the space that
978  * has been freed up since the snapshot was taken.
979  */
980 void
981 dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
982 {
983 	uint64_t mrs_used;
984 	uint64_t dlused, dlcomp, dluncomp;
985 
986 	ASSERT(!ds->ds_is_snapshot);
987 
988 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0)
989 		mrs_used = dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes;
990 	else
991 		mrs_used = 0;
992 
993 	dsl_deadlist_space(&ds->ds_deadlist, &dlused, &dlcomp, &dluncomp);
994 
995 	ASSERT3U(dlused, <=, mrs_used);
996 	dsl_dataset_phys(ds)->ds_unique_bytes =
997 	    dsl_dataset_phys(ds)->ds_referenced_bytes - (mrs_used - dlused);
998 
999 	if (spa_version(ds->ds_dir->dd_pool->dp_spa) >=
1000 	    SPA_VERSION_UNIQUE_ACCURATE)
1001 		dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1002 }
1003 
1004 void
1005 dsl_dataset_remove_from_next_clones(dsl_dataset_t *ds, uint64_t obj,
1006     dmu_tx_t *tx)
1007 {
1008 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1009 	uint64_t count;
1010 	int err;
1011 
1012 	ASSERT(dsl_dataset_phys(ds)->ds_num_children >= 2);
1013 	err = zap_remove_int(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
1014 	    obj, tx);
1015 	/*
1016 	 * The err should not be ENOENT, but a bug in a previous version
1017 	 * of the code could cause upgrade_clones_cb() to not set
1018 	 * ds_next_snap_obj when it should, leading to a missing entry.
1019 	 * If we knew that the pool was created after
1020 	 * SPA_VERSION_NEXT_CLONES, we could assert that it isn't
1021 	 * ENOENT.  However, at least we can check that we don't have
1022 	 * too many entries in the next_clones_obj even after failing to
1023 	 * remove this one.
1024 	 */
1025 	if (err != ENOENT)
1026 		VERIFY0(err);
1027 	ASSERT0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
1028 	    &count));
1029 	ASSERT3U(count, <=, dsl_dataset_phys(ds)->ds_num_children - 2);
1030 }
1031 
1032 
1033 blkptr_t *
1034 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
1035 {
1036 	return (&dsl_dataset_phys(ds)->ds_bp);
1037 }
1038 
1039 spa_t *
1040 dsl_dataset_get_spa(dsl_dataset_t *ds)
1041 {
1042 	return (ds->ds_dir->dd_pool->dp_spa);
1043 }
1044 
1045 void
1046 dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
1047 {
1048 	dsl_pool_t *dp;
1049 
1050 	if (ds == NULL) /* this is the meta-objset */
1051 		return;
1052 
1053 	ASSERT(ds->ds_objset != NULL);
1054 
1055 	if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0)
1056 		panic("dirtying snapshot!");
1057 
1058 	dp = ds->ds_dir->dd_pool;
1059 
1060 	if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg)) {
1061 		/* up the hold count until we can be written out */
1062 		dmu_buf_add_ref(ds->ds_dbuf, ds);
1063 	}
1064 }
1065 
1066 boolean_t
1067 dsl_dataset_is_dirty(dsl_dataset_t *ds)
1068 {
1069 	for (int t = 0; t < TXG_SIZE; t++) {
1070 		if (txg_list_member(&ds->ds_dir->dd_pool->dp_dirty_datasets,
1071 		    ds, t))
1072 			return (B_TRUE);
1073 	}
1074 	return (B_FALSE);
1075 }
1076 
1077 static int
1078 dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx)
1079 {
1080 	uint64_t asize;
1081 
1082 	if (!dmu_tx_is_syncing(tx))
1083 		return (0);
1084 
1085 	/*
1086 	 * If there's an fs-only reservation, any blocks that might become
1087 	 * owned by the snapshot dataset must be accommodated by space
1088 	 * outside of the reservation.
1089 	 */
1090 	ASSERT(ds->ds_reserved == 0 || DS_UNIQUE_IS_ACCURATE(ds));
1091 	asize = MIN(dsl_dataset_phys(ds)->ds_unique_bytes, ds->ds_reserved);
1092 	if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE))
1093 		return (SET_ERROR(ENOSPC));
1094 
1095 	/*
1096 	 * Propagate any reserved space for this snapshot to other
1097 	 * snapshot checks in this sync group.
1098 	 */
1099 	if (asize > 0)
1100 		dsl_dir_willuse_space(ds->ds_dir, asize, tx);
1101 
1102 	return (0);
1103 }
1104 
1105 typedef struct dsl_dataset_snapshot_arg {
1106 	nvlist_t *ddsa_snaps;
1107 	nvlist_t *ddsa_props;
1108 	nvlist_t *ddsa_errors;
1109 	cred_t *ddsa_cr;
1110 } dsl_dataset_snapshot_arg_t;
1111 
1112 int
1113 dsl_dataset_snapshot_check_impl(dsl_dataset_t *ds, const char *snapname,
1114     dmu_tx_t *tx, boolean_t recv, uint64_t cnt, cred_t *cr)
1115 {
1116 	int error;
1117 	uint64_t value;
1118 
1119 	ds->ds_trysnap_txg = tx->tx_txg;
1120 
1121 	if (!dmu_tx_is_syncing(tx))
1122 		return (0);
1123 
1124 	/*
1125 	 * We don't allow multiple snapshots of the same txg.  If there
1126 	 * is already one, try again.
1127 	 */
1128 	if (dsl_dataset_phys(ds)->ds_prev_snap_txg >= tx->tx_txg)
1129 		return (SET_ERROR(EAGAIN));
1130 
1131 	/*
1132 	 * Check for conflicting snapshot name.
1133 	 */
1134 	error = dsl_dataset_snap_lookup(ds, snapname, &value);
1135 	if (error == 0)
1136 		return (SET_ERROR(EEXIST));
1137 	if (error != ENOENT)
1138 		return (error);
1139 
1140 	/*
1141 	 * We don't allow taking snapshots of inconsistent datasets, such as
1142 	 * those into which we are currently receiving.  However, if we are
1143 	 * creating this snapshot as part of a receive, this check will be
1144 	 * executed atomically with respect to the completion of the receive
1145 	 * itself but prior to the clearing of DS_FLAG_INCONSISTENT; in this
1146 	 * case we ignore this, knowing it will be fixed up for us shortly in
1147 	 * dmu_recv_end_sync().
1148 	 */
1149 	if (!recv && DS_IS_INCONSISTENT(ds))
1150 		return (SET_ERROR(EBUSY));
1151 
1152 	/*
1153 	 * Skip the check for temporary snapshots or if we have already checked
1154 	 * the counts in dsl_dataset_snapshot_check. This means we really only
1155 	 * check the count here when we're receiving a stream.
1156 	 */
1157 	if (cnt != 0 && cr != NULL) {
1158 		error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1159 		    ZFS_PROP_SNAPSHOT_LIMIT, NULL, cr);
1160 		if (error != 0)
1161 			return (error);
1162 	}
1163 
1164 	error = dsl_dataset_snapshot_reserve_space(ds, tx);
1165 	if (error != 0)
1166 		return (error);
1167 
1168 	return (0);
1169 }
1170 
1171 static int
1172 dsl_dataset_snapshot_check(void *arg, dmu_tx_t *tx)
1173 {
1174 	dsl_dataset_snapshot_arg_t *ddsa = arg;
1175 	dsl_pool_t *dp = dmu_tx_pool(tx);
1176 	nvpair_t *pair;
1177 	int rv = 0;
1178 
1179 	/*
1180 	 * Pre-compute how many total new snapshots will be created for each
1181 	 * level in the tree and below. This is needed for validating the
1182 	 * snapshot limit when either taking a recursive snapshot or when
1183 	 * taking multiple snapshots.
1184 	 *
1185 	 * The problem is that the counts are not actually adjusted when
1186 	 * we are checking, only when we finally sync. For a single snapshot,
1187 	 * this is easy, the count will increase by 1 at each node up the tree,
1188 	 * but its more complicated for the recursive/multiple snapshot case.
1189 	 *
1190 	 * The dsl_fs_ss_limit_check function does recursively check the count
1191 	 * at each level up the tree but since it is validating each snapshot
1192 	 * independently we need to be sure that we are validating the complete
1193 	 * count for the entire set of snapshots. We do this by rolling up the
1194 	 * counts for each component of the name into an nvlist and then
1195 	 * checking each of those cases with the aggregated count.
1196 	 *
1197 	 * This approach properly handles not only the recursive snapshot
1198 	 * case (where we get all of those on the ddsa_snaps list) but also
1199 	 * the sibling case (e.g. snapshot a/b and a/c so that we will also
1200 	 * validate the limit on 'a' using a count of 2).
1201 	 *
1202 	 * We validate the snapshot names in the third loop and only report
1203 	 * name errors once.
1204 	 */
1205 	if (dmu_tx_is_syncing(tx)) {
1206 		nvlist_t *cnt_track = NULL;
1207 		cnt_track = fnvlist_alloc();
1208 
1209 		/* Rollup aggregated counts into the cnt_track list */
1210 		for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1211 		    pair != NULL;
1212 		    pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1213 			char *pdelim;
1214 			uint64_t val;
1215 			char nm[MAXPATHLEN];
1216 
1217 			(void) strlcpy(nm, nvpair_name(pair), sizeof (nm));
1218 			pdelim = strchr(nm, '@');
1219 			if (pdelim == NULL)
1220 				continue;
1221 			*pdelim = '\0';
1222 
1223 			do {
1224 				if (nvlist_lookup_uint64(cnt_track, nm,
1225 				    &val) == 0) {
1226 					/* update existing entry */
1227 					fnvlist_add_uint64(cnt_track, nm,
1228 					    val + 1);
1229 				} else {
1230 					/* add to list */
1231 					fnvlist_add_uint64(cnt_track, nm, 1);
1232 				}
1233 
1234 				pdelim = strrchr(nm, '/');
1235 				if (pdelim != NULL)
1236 					*pdelim = '\0';
1237 			} while (pdelim != NULL);
1238 		}
1239 
1240 		/* Check aggregated counts at each level */
1241 		for (pair = nvlist_next_nvpair(cnt_track, NULL);
1242 		    pair != NULL; pair = nvlist_next_nvpair(cnt_track, pair)) {
1243 			int error = 0;
1244 			char *name;
1245 			uint64_t cnt = 0;
1246 			dsl_dataset_t *ds;
1247 
1248 			name = nvpair_name(pair);
1249 			cnt = fnvpair_value_uint64(pair);
1250 			ASSERT(cnt > 0);
1251 
1252 			error = dsl_dataset_hold(dp, name, FTAG, &ds);
1253 			if (error == 0) {
1254 				error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1255 				    ZFS_PROP_SNAPSHOT_LIMIT, NULL,
1256 				    ddsa->ddsa_cr);
1257 				dsl_dataset_rele(ds, FTAG);
1258 			}
1259 
1260 			if (error != 0) {
1261 				if (ddsa->ddsa_errors != NULL)
1262 					fnvlist_add_int32(ddsa->ddsa_errors,
1263 					    name, error);
1264 				rv = error;
1265 				/* only report one error for this check */
1266 				break;
1267 			}
1268 		}
1269 		nvlist_free(cnt_track);
1270 	}
1271 
1272 	for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1273 	    pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1274 		int error = 0;
1275 		dsl_dataset_t *ds;
1276 		char *name, *atp;
1277 		char dsname[ZFS_MAX_DATASET_NAME_LEN];
1278 
1279 		name = nvpair_name(pair);
1280 		if (strlen(name) >= ZFS_MAX_DATASET_NAME_LEN)
1281 			error = SET_ERROR(ENAMETOOLONG);
1282 		if (error == 0) {
1283 			atp = strchr(name, '@');
1284 			if (atp == NULL)
1285 				error = SET_ERROR(EINVAL);
1286 			if (error == 0)
1287 				(void) strlcpy(dsname, name, atp - name + 1);
1288 		}
1289 		if (error == 0)
1290 			error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
1291 		if (error == 0) {
1292 			/* passing 0/NULL skips dsl_fs_ss_limit_check */
1293 			error = dsl_dataset_snapshot_check_impl(ds,
1294 			    atp + 1, tx, B_FALSE, 0, NULL);
1295 			dsl_dataset_rele(ds, FTAG);
1296 		}
1297 
1298 		if (error != 0) {
1299 			if (ddsa->ddsa_errors != NULL) {
1300 				fnvlist_add_int32(ddsa->ddsa_errors,
1301 				    name, error);
1302 			}
1303 			rv = error;
1304 		}
1305 	}
1306 
1307 	return (rv);
1308 }
1309 
1310 void
1311 dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
1312     dmu_tx_t *tx)
1313 {
1314 	static zil_header_t zero_zil;
1315 
1316 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1317 	dmu_buf_t *dbuf;
1318 	dsl_dataset_phys_t *dsphys;
1319 	uint64_t dsobj, crtxg;
1320 	objset_t *mos = dp->dp_meta_objset;
1321 	objset_t *os;
1322 
1323 	ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
1324 
1325 	/*
1326 	 * If we are on an old pool, the zil must not be active, in which
1327 	 * case it will be zeroed.  Usually zil_suspend() accomplishes this.
1328 	 */
1329 	ASSERT(spa_version(dmu_tx_pool(tx)->dp_spa) >= SPA_VERSION_FAST_SNAP ||
1330 	    dmu_objset_from_ds(ds, &os) != 0 ||
1331 	    bcmp(&os->os_phys->os_zil_header, &zero_zil,
1332 	    sizeof (zero_zil)) == 0);
1333 
1334 	dsl_fs_ss_count_adjust(ds->ds_dir, 1, DD_FIELD_SNAPSHOT_COUNT, tx);
1335 
1336 	/*
1337 	 * The origin's ds_creation_txg has to be < TXG_INITIAL
1338 	 */
1339 	if (strcmp(snapname, ORIGIN_DIR_NAME) == 0)
1340 		crtxg = 1;
1341 	else
1342 		crtxg = tx->tx_txg;
1343 
1344 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1345 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1346 	VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1347 	dmu_buf_will_dirty(dbuf, tx);
1348 	dsphys = dbuf->db_data;
1349 	bzero(dsphys, sizeof (dsl_dataset_phys_t));
1350 	dsphys->ds_dir_obj = ds->ds_dir->dd_object;
1351 	dsphys->ds_fsid_guid = unique_create();
1352 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1353 	    sizeof (dsphys->ds_guid));
1354 	dsphys->ds_prev_snap_obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
1355 	dsphys->ds_prev_snap_txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
1356 	dsphys->ds_next_snap_obj = ds->ds_object;
1357 	dsphys->ds_num_children = 1;
1358 	dsphys->ds_creation_time = gethrestime_sec();
1359 	dsphys->ds_creation_txg = crtxg;
1360 	dsphys->ds_deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
1361 	dsphys->ds_referenced_bytes = dsl_dataset_phys(ds)->ds_referenced_bytes;
1362 	dsphys->ds_compressed_bytes = dsl_dataset_phys(ds)->ds_compressed_bytes;
1363 	dsphys->ds_uncompressed_bytes =
1364 	    dsl_dataset_phys(ds)->ds_uncompressed_bytes;
1365 	dsphys->ds_flags = dsl_dataset_phys(ds)->ds_flags;
1366 	rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1367 	dsphys->ds_bp = dsl_dataset_phys(ds)->ds_bp;
1368 	rrw_exit(&ds->ds_bp_rwlock, FTAG);
1369 	dmu_buf_rele(dbuf, FTAG);
1370 
1371 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1372 		if (ds->ds_feature_inuse[f])
1373 			dsl_dataset_activate_feature(dsobj, f, tx);
1374 	}
1375 
1376 	ASSERT3U(ds->ds_prev != 0, ==,
1377 	    dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
1378 	if (ds->ds_prev) {
1379 		uint64_t next_clones_obj =
1380 		    dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj;
1381 		ASSERT(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1382 		    ds->ds_object ||
1383 		    dsl_dataset_phys(ds->ds_prev)->ds_num_children > 1);
1384 		if (dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1385 		    ds->ds_object) {
1386 			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1387 			ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
1388 			    dsl_dataset_phys(ds->ds_prev)->ds_creation_txg);
1389 			dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj = dsobj;
1390 		} else if (next_clones_obj != 0) {
1391 			dsl_dataset_remove_from_next_clones(ds->ds_prev,
1392 			    dsphys->ds_next_snap_obj, tx);
1393 			VERIFY0(zap_add_int(mos,
1394 			    next_clones_obj, dsobj, tx));
1395 		}
1396 	}
1397 
1398 	/*
1399 	 * If we have a reference-reservation on this dataset, we will
1400 	 * need to increase the amount of refreservation being charged
1401 	 * since our unique space is going to zero.
1402 	 */
1403 	if (ds->ds_reserved) {
1404 		int64_t delta;
1405 		ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
1406 		delta = MIN(dsl_dataset_phys(ds)->ds_unique_bytes,
1407 		    ds->ds_reserved);
1408 		dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV,
1409 		    delta, 0, 0, tx);
1410 	}
1411 
1412 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1413 	dsl_dataset_phys(ds)->ds_deadlist_obj =
1414 	    dsl_deadlist_clone(&ds->ds_deadlist, UINT64_MAX,
1415 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, tx);
1416 	dsl_deadlist_close(&ds->ds_deadlist);
1417 	dsl_deadlist_open(&ds->ds_deadlist, mos,
1418 	    dsl_dataset_phys(ds)->ds_deadlist_obj);
1419 	dsl_deadlist_add_key(&ds->ds_deadlist,
1420 	    dsl_dataset_phys(ds)->ds_prev_snap_txg, tx);
1421 
1422 	ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, <, tx->tx_txg);
1423 	dsl_dataset_phys(ds)->ds_prev_snap_obj = dsobj;
1424 	dsl_dataset_phys(ds)->ds_prev_snap_txg = crtxg;
1425 	dsl_dataset_phys(ds)->ds_unique_bytes = 0;
1426 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1427 		dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1428 
1429 	VERIFY0(zap_add(mos, dsl_dataset_phys(ds)->ds_snapnames_zapobj,
1430 	    snapname, 8, 1, &dsobj, tx));
1431 
1432 	if (ds->ds_prev)
1433 		dsl_dataset_rele(ds->ds_prev, ds);
1434 	VERIFY0(dsl_dataset_hold_obj(dp,
1435 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, ds, &ds->ds_prev));
1436 
1437 	dsl_scan_ds_snapshotted(ds, tx);
1438 
1439 	dsl_dir_snap_cmtime_update(ds->ds_dir);
1440 
1441 	spa_history_log_internal_ds(ds->ds_prev, "snapshot", tx, "");
1442 }
1443 
1444 static void
1445 dsl_dataset_snapshot_sync(void *arg, dmu_tx_t *tx)
1446 {
1447 	dsl_dataset_snapshot_arg_t *ddsa = arg;
1448 	dsl_pool_t *dp = dmu_tx_pool(tx);
1449 	nvpair_t *pair;
1450 
1451 	for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1452 	    pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1453 		dsl_dataset_t *ds;
1454 		char *name, *atp;
1455 		char dsname[ZFS_MAX_DATASET_NAME_LEN];
1456 
1457 		name = nvpair_name(pair);
1458 		atp = strchr(name, '@');
1459 		(void) strlcpy(dsname, name, atp - name + 1);
1460 		VERIFY0(dsl_dataset_hold(dp, dsname, FTAG, &ds));
1461 
1462 		dsl_dataset_snapshot_sync_impl(ds, atp + 1, tx);
1463 		if (ddsa->ddsa_props != NULL) {
1464 			dsl_props_set_sync_impl(ds->ds_prev,
1465 			    ZPROP_SRC_LOCAL, ddsa->ddsa_props, tx);
1466 		}
1467 		dsl_dataset_rele(ds, FTAG);
1468 	}
1469 }
1470 
1471 /*
1472  * The snapshots must all be in the same pool.
1473  * All-or-nothing: if there are any failures, nothing will be modified.
1474  */
1475 int
1476 dsl_dataset_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t *errors)
1477 {
1478 	dsl_dataset_snapshot_arg_t ddsa;
1479 	nvpair_t *pair;
1480 	boolean_t needsuspend;
1481 	int error;
1482 	spa_t *spa;
1483 	char *firstname;
1484 	nvlist_t *suspended = NULL;
1485 
1486 	pair = nvlist_next_nvpair(snaps, NULL);
1487 	if (pair == NULL)
1488 		return (0);
1489 	firstname = nvpair_name(pair);
1490 
1491 	error = spa_open(firstname, &spa, FTAG);
1492 	if (error != 0)
1493 		return (error);
1494 	needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1495 	spa_close(spa, FTAG);
1496 
1497 	if (needsuspend) {
1498 		suspended = fnvlist_alloc();
1499 		for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
1500 		    pair = nvlist_next_nvpair(snaps, pair)) {
1501 			char fsname[ZFS_MAX_DATASET_NAME_LEN];
1502 			char *snapname = nvpair_name(pair);
1503 			char *atp;
1504 			void *cookie;
1505 
1506 			atp = strchr(snapname, '@');
1507 			if (atp == NULL) {
1508 				error = SET_ERROR(EINVAL);
1509 				break;
1510 			}
1511 			(void) strlcpy(fsname, snapname, atp - snapname + 1);
1512 
1513 			error = zil_suspend(fsname, &cookie);
1514 			if (error != 0)
1515 				break;
1516 			fnvlist_add_uint64(suspended, fsname,
1517 			    (uintptr_t)cookie);
1518 		}
1519 	}
1520 
1521 	ddsa.ddsa_snaps = snaps;
1522 	ddsa.ddsa_props = props;
1523 	ddsa.ddsa_errors = errors;
1524 	ddsa.ddsa_cr = CRED();
1525 
1526 	if (error == 0) {
1527 		error = dsl_sync_task(firstname, dsl_dataset_snapshot_check,
1528 		    dsl_dataset_snapshot_sync, &ddsa,
1529 		    fnvlist_num_pairs(snaps) * 3, ZFS_SPACE_CHECK_NORMAL);
1530 	}
1531 
1532 	if (suspended != NULL) {
1533 		for (pair = nvlist_next_nvpair(suspended, NULL); pair != NULL;
1534 		    pair = nvlist_next_nvpair(suspended, pair)) {
1535 			zil_resume((void *)(uintptr_t)
1536 			    fnvpair_value_uint64(pair));
1537 		}
1538 		fnvlist_free(suspended);
1539 	}
1540 
1541 	return (error);
1542 }
1543 
1544 typedef struct dsl_dataset_snapshot_tmp_arg {
1545 	const char *ddsta_fsname;
1546 	const char *ddsta_snapname;
1547 	minor_t ddsta_cleanup_minor;
1548 	const char *ddsta_htag;
1549 } dsl_dataset_snapshot_tmp_arg_t;
1550 
1551 static int
1552 dsl_dataset_snapshot_tmp_check(void *arg, dmu_tx_t *tx)
1553 {
1554 	dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1555 	dsl_pool_t *dp = dmu_tx_pool(tx);
1556 	dsl_dataset_t *ds;
1557 	int error;
1558 
1559 	error = dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds);
1560 	if (error != 0)
1561 		return (error);
1562 
1563 	/* NULL cred means no limit check for tmp snapshot */
1564 	error = dsl_dataset_snapshot_check_impl(ds, ddsta->ddsta_snapname,
1565 	    tx, B_FALSE, 0, NULL);
1566 	if (error != 0) {
1567 		dsl_dataset_rele(ds, FTAG);
1568 		return (error);
1569 	}
1570 
1571 	if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS) {
1572 		dsl_dataset_rele(ds, FTAG);
1573 		return (SET_ERROR(ENOTSUP));
1574 	}
1575 	error = dsl_dataset_user_hold_check_one(NULL, ddsta->ddsta_htag,
1576 	    B_TRUE, tx);
1577 	if (error != 0) {
1578 		dsl_dataset_rele(ds, FTAG);
1579 		return (error);
1580 	}
1581 
1582 	dsl_dataset_rele(ds, FTAG);
1583 	return (0);
1584 }
1585 
1586 static void
1587 dsl_dataset_snapshot_tmp_sync(void *arg, dmu_tx_t *tx)
1588 {
1589 	dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1590 	dsl_pool_t *dp = dmu_tx_pool(tx);
1591 	dsl_dataset_t *ds;
1592 
1593 	VERIFY0(dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds));
1594 
1595 	dsl_dataset_snapshot_sync_impl(ds, ddsta->ddsta_snapname, tx);
1596 	dsl_dataset_user_hold_sync_one(ds->ds_prev, ddsta->ddsta_htag,
1597 	    ddsta->ddsta_cleanup_minor, gethrestime_sec(), tx);
1598 	dsl_destroy_snapshot_sync_impl(ds->ds_prev, B_TRUE, tx);
1599 
1600 	dsl_dataset_rele(ds, FTAG);
1601 }
1602 
1603 int
1604 dsl_dataset_snapshot_tmp(const char *fsname, const char *snapname,
1605     minor_t cleanup_minor, const char *htag)
1606 {
1607 	dsl_dataset_snapshot_tmp_arg_t ddsta;
1608 	int error;
1609 	spa_t *spa;
1610 	boolean_t needsuspend;
1611 	void *cookie;
1612 
1613 	ddsta.ddsta_fsname = fsname;
1614 	ddsta.ddsta_snapname = snapname;
1615 	ddsta.ddsta_cleanup_minor = cleanup_minor;
1616 	ddsta.ddsta_htag = htag;
1617 
1618 	error = spa_open(fsname, &spa, FTAG);
1619 	if (error != 0)
1620 		return (error);
1621 	needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1622 	spa_close(spa, FTAG);
1623 
1624 	if (needsuspend) {
1625 		error = zil_suspend(fsname, &cookie);
1626 		if (error != 0)
1627 			return (error);
1628 	}
1629 
1630 	error = dsl_sync_task(fsname, dsl_dataset_snapshot_tmp_check,
1631 	    dsl_dataset_snapshot_tmp_sync, &ddsta, 3, ZFS_SPACE_CHECK_RESERVED);
1632 
1633 	if (needsuspend)
1634 		zil_resume(cookie);
1635 	return (error);
1636 }
1637 
1638 
1639 void
1640 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
1641 {
1642 	ASSERT(dmu_tx_is_syncing(tx));
1643 	ASSERT(ds->ds_objset != NULL);
1644 	ASSERT(dsl_dataset_phys(ds)->ds_next_snap_obj == 0);
1645 
1646 	/*
1647 	 * in case we had to change ds_fsid_guid when we opened it,
1648 	 * sync it out now.
1649 	 */
1650 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1651 	dsl_dataset_phys(ds)->ds_fsid_guid = ds->ds_fsid_guid;
1652 
1653 	if (ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] != 0) {
1654 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1655 		    ds->ds_object, DS_FIELD_RESUME_OBJECT, 8, 1,
1656 		    &ds->ds_resume_object[tx->tx_txg & TXG_MASK], tx));
1657 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1658 		    ds->ds_object, DS_FIELD_RESUME_OFFSET, 8, 1,
1659 		    &ds->ds_resume_offset[tx->tx_txg & TXG_MASK], tx));
1660 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1661 		    ds->ds_object, DS_FIELD_RESUME_BYTES, 8, 1,
1662 		    &ds->ds_resume_bytes[tx->tx_txg & TXG_MASK], tx));
1663 		ds->ds_resume_object[tx->tx_txg & TXG_MASK] = 0;
1664 		ds->ds_resume_offset[tx->tx_txg & TXG_MASK] = 0;
1665 		ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] = 0;
1666 	}
1667 
1668 	dmu_objset_sync(ds->ds_objset, zio, tx);
1669 
1670 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1671 		if (ds->ds_feature_activation_needed[f]) {
1672 			if (ds->ds_feature_inuse[f])
1673 				continue;
1674 			dsl_dataset_activate_feature(ds->ds_object, f, tx);
1675 			ds->ds_feature_inuse[f] = B_TRUE;
1676 		}
1677 	}
1678 }
1679 
1680 static void
1681 get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
1682 {
1683 	uint64_t count = 0;
1684 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1685 	zap_cursor_t zc;
1686 	zap_attribute_t za;
1687 	nvlist_t *propval = fnvlist_alloc();
1688 	nvlist_t *val = fnvlist_alloc();
1689 
1690 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
1691 
1692 	/*
1693 	 * There may be missing entries in ds_next_clones_obj
1694 	 * due to a bug in a previous version of the code.
1695 	 * Only trust it if it has the right number of entries.
1696 	 */
1697 	if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
1698 		VERIFY0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
1699 		    &count));
1700 	}
1701 	if (count != dsl_dataset_phys(ds)->ds_num_children - 1)
1702 		goto fail;
1703 	for (zap_cursor_init(&zc, mos,
1704 	    dsl_dataset_phys(ds)->ds_next_clones_obj);
1705 	    zap_cursor_retrieve(&zc, &za) == 0;
1706 	    zap_cursor_advance(&zc)) {
1707 		dsl_dataset_t *clone;
1708 		char buf[ZFS_MAX_DATASET_NAME_LEN];
1709 		VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
1710 		    za.za_first_integer, FTAG, &clone));
1711 		dsl_dir_name(clone->ds_dir, buf);
1712 		fnvlist_add_boolean(val, buf);
1713 		dsl_dataset_rele(clone, FTAG);
1714 	}
1715 	zap_cursor_fini(&zc);
1716 	fnvlist_add_nvlist(propval, ZPROP_VALUE, val);
1717 	fnvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES), propval);
1718 fail:
1719 	nvlist_free(val);
1720 	nvlist_free(propval);
1721 }
1722 
1723 static void
1724 get_receive_resume_stats(dsl_dataset_t *ds, nvlist_t *nv)
1725 {
1726 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1727 
1728 	if (dsl_dataset_has_resume_receive_state(ds)) {
1729 		char *str;
1730 		void *packed;
1731 		uint8_t *compressed;
1732 		uint64_t val;
1733 		nvlist_t *token_nv = fnvlist_alloc();
1734 		size_t packed_size, compressed_size;
1735 
1736 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1737 		    DS_FIELD_RESUME_FROMGUID, sizeof (val), 1, &val) == 0) {
1738 			fnvlist_add_uint64(token_nv, "fromguid", val);
1739 		}
1740 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1741 		    DS_FIELD_RESUME_OBJECT, sizeof (val), 1, &val) == 0) {
1742 			fnvlist_add_uint64(token_nv, "object", val);
1743 		}
1744 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1745 		    DS_FIELD_RESUME_OFFSET, sizeof (val), 1, &val) == 0) {
1746 			fnvlist_add_uint64(token_nv, "offset", val);
1747 		}
1748 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1749 		    DS_FIELD_RESUME_BYTES, sizeof (val), 1, &val) == 0) {
1750 			fnvlist_add_uint64(token_nv, "bytes", val);
1751 		}
1752 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1753 		    DS_FIELD_RESUME_TOGUID, sizeof (val), 1, &val) == 0) {
1754 			fnvlist_add_uint64(token_nv, "toguid", val);
1755 		}
1756 		char buf[256];
1757 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1758 		    DS_FIELD_RESUME_TONAME, 1, sizeof (buf), buf) == 0) {
1759 			fnvlist_add_string(token_nv, "toname", buf);
1760 		}
1761 		if (zap_contains(dp->dp_meta_objset, ds->ds_object,
1762 		    DS_FIELD_RESUME_EMBEDOK) == 0) {
1763 			fnvlist_add_boolean(token_nv, "embedok");
1764 		}
1765 		packed = fnvlist_pack(token_nv, &packed_size);
1766 		fnvlist_free(token_nv);
1767 		compressed = kmem_alloc(packed_size, KM_SLEEP);
1768 
1769 		compressed_size = gzip_compress(packed, compressed,
1770 		    packed_size, packed_size, 6);
1771 
1772 		zio_cksum_t cksum;
1773 		fletcher_4_native(compressed, compressed_size, NULL, &cksum);
1774 
1775 		str = kmem_alloc(compressed_size * 2 + 1, KM_SLEEP);
1776 		for (int i = 0; i < compressed_size; i++) {
1777 			(void) sprintf(str + i * 2, "%02x", compressed[i]);
1778 		}
1779 		str[compressed_size * 2] = '\0';
1780 		char *propval = kmem_asprintf("%u-%llx-%llx-%s",
1781 		    ZFS_SEND_RESUME_TOKEN_VERSION,
1782 		    (longlong_t)cksum.zc_word[0],
1783 		    (longlong_t)packed_size, str);
1784 		dsl_prop_nvlist_add_string(nv,
1785 		    ZFS_PROP_RECEIVE_RESUME_TOKEN, propval);
1786 		kmem_free(packed, packed_size);
1787 		kmem_free(str, compressed_size * 2 + 1);
1788 		kmem_free(compressed, packed_size);
1789 		strfree(propval);
1790 	}
1791 }
1792 
1793 void
1794 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
1795 {
1796 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1797 	uint64_t refd, avail, uobjs, aobjs, ratio;
1798 
1799 	ASSERT(dsl_pool_config_held(dp));
1800 
1801 	ratio = dsl_dataset_phys(ds)->ds_compressed_bytes == 0 ? 100 :
1802 	    (dsl_dataset_phys(ds)->ds_uncompressed_bytes * 100 /
1803 	    dsl_dataset_phys(ds)->ds_compressed_bytes);
1804 
1805 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRATIO, ratio);
1806 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALREFERENCED,
1807 	    dsl_dataset_phys(ds)->ds_uncompressed_bytes);
1808 
1809 	if (ds->ds_is_snapshot) {
1810 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
1811 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
1812 		    dsl_dataset_phys(ds)->ds_unique_bytes);
1813 		get_clones_stat(ds, nv);
1814 	} else {
1815 		if (ds->ds_prev != NULL && ds->ds_prev != dp->dp_origin_snap) {
1816 			char buf[ZFS_MAX_DATASET_NAME_LEN];
1817 			dsl_dataset_name(ds->ds_prev, buf);
1818 			dsl_prop_nvlist_add_string(nv, ZFS_PROP_PREV_SNAP, buf);
1819 		}
1820 
1821 		dsl_dir_stats(ds->ds_dir, nv);
1822 	}
1823 
1824 	dsl_dataset_space(ds, &refd, &avail, &uobjs, &aobjs);
1825 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE, avail);
1826 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED, refd);
1827 
1828 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION,
1829 	    dsl_dataset_phys(ds)->ds_creation_time);
1830 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG,
1831 	    dsl_dataset_phys(ds)->ds_creation_txg);
1832 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA,
1833 	    ds->ds_quota);
1834 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION,
1835 	    ds->ds_reserved);
1836 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_GUID,
1837 	    dsl_dataset_phys(ds)->ds_guid);
1838 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_UNIQUE,
1839 	    dsl_dataset_phys(ds)->ds_unique_bytes);
1840 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_OBJSETID,
1841 	    ds->ds_object);
1842 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERREFS,
1843 	    ds->ds_userrefs);
1844 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
1845 	    DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
1846 
1847 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1848 		uint64_t written, comp, uncomp;
1849 		dsl_pool_t *dp = ds->ds_dir->dd_pool;
1850 		dsl_dataset_t *prev;
1851 
1852 		int err = dsl_dataset_hold_obj(dp,
1853 		    dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1854 		if (err == 0) {
1855 			err = dsl_dataset_space_written(prev, ds, &written,
1856 			    &comp, &uncomp);
1857 			dsl_dataset_rele(prev, FTAG);
1858 			if (err == 0) {
1859 				dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
1860 				    written);
1861 			}
1862 		}
1863 	}
1864 
1865 	if (!dsl_dataset_is_snapshot(ds)) {
1866 		/*
1867 		 * A failed "newfs" (e.g. full) resumable receive leaves
1868 		 * the stats set on this dataset.  Check here for the prop.
1869 		 */
1870 		get_receive_resume_stats(ds, nv);
1871 
1872 		/*
1873 		 * A failed incremental resumable receive leaves the
1874 		 * stats set on our child named "%recv".  Check the child
1875 		 * for the prop.
1876 		 */
1877 		/* 6 extra bytes for /%recv */
1878 		char recvname[ZFS_MAX_DATASET_NAME_LEN + 6];
1879 		dsl_dataset_t *recv_ds;
1880 		dsl_dataset_name(ds, recvname);
1881 		if (strlcat(recvname, "/", sizeof (recvname)) <
1882 		    sizeof (recvname) &&
1883 		    strlcat(recvname, recv_clone_name, sizeof (recvname)) <
1884 		    sizeof (recvname) &&
1885 		    dsl_dataset_hold(dp, recvname, FTAG, &recv_ds) == 0) {
1886 			get_receive_resume_stats(recv_ds, nv);
1887 			dsl_dataset_rele(recv_ds, FTAG);
1888 		}
1889 	}
1890 }
1891 
1892 void
1893 dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat)
1894 {
1895 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1896 	ASSERT(dsl_pool_config_held(dp));
1897 
1898 	stat->dds_creation_txg = dsl_dataset_phys(ds)->ds_creation_txg;
1899 	stat->dds_inconsistent =
1900 	    dsl_dataset_phys(ds)->ds_flags & DS_FLAG_INCONSISTENT;
1901 	stat->dds_guid = dsl_dataset_phys(ds)->ds_guid;
1902 	stat->dds_origin[0] = '\0';
1903 	if (ds->ds_is_snapshot) {
1904 		stat->dds_is_snapshot = B_TRUE;
1905 		stat->dds_num_clones =
1906 		    dsl_dataset_phys(ds)->ds_num_children - 1;
1907 	} else {
1908 		stat->dds_is_snapshot = B_FALSE;
1909 		stat->dds_num_clones = 0;
1910 
1911 		if (dsl_dir_is_clone(ds->ds_dir)) {
1912 			dsl_dataset_t *ods;
1913 
1914 			VERIFY0(dsl_dataset_hold_obj(dp,
1915 			    dsl_dir_phys(ds->ds_dir)->dd_origin_obj,
1916 			    FTAG, &ods));
1917 			dsl_dataset_name(ods, stat->dds_origin);
1918 			dsl_dataset_rele(ods, FTAG);
1919 		}
1920 	}
1921 }
1922 
1923 uint64_t
1924 dsl_dataset_fsid_guid(dsl_dataset_t *ds)
1925 {
1926 	return (ds->ds_fsid_guid);
1927 }
1928 
1929 void
1930 dsl_dataset_space(dsl_dataset_t *ds,
1931     uint64_t *refdbytesp, uint64_t *availbytesp,
1932     uint64_t *usedobjsp, uint64_t *availobjsp)
1933 {
1934 	*refdbytesp = dsl_dataset_phys(ds)->ds_referenced_bytes;
1935 	*availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE);
1936 	if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes)
1937 		*availbytesp +=
1938 		    ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes;
1939 	if (ds->ds_quota != 0) {
1940 		/*
1941 		 * Adjust available bytes according to refquota
1942 		 */
1943 		if (*refdbytesp < ds->ds_quota)
1944 			*availbytesp = MIN(*availbytesp,
1945 			    ds->ds_quota - *refdbytesp);
1946 		else
1947 			*availbytesp = 0;
1948 	}
1949 	rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1950 	*usedobjsp = BP_GET_FILL(&dsl_dataset_phys(ds)->ds_bp);
1951 	rrw_exit(&ds->ds_bp_rwlock, FTAG);
1952 	*availobjsp = DN_MAX_OBJECT - *usedobjsp;
1953 }
1954 
1955 boolean_t
1956 dsl_dataset_modified_since_snap(dsl_dataset_t *ds, dsl_dataset_t *snap)
1957 {
1958 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1959 	uint64_t birth;
1960 
1961 	ASSERT(dsl_pool_config_held(dp));
1962 	if (snap == NULL)
1963 		return (B_FALSE);
1964 	rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1965 	birth = dsl_dataset_get_blkptr(ds)->blk_birth;
1966 	rrw_exit(&ds->ds_bp_rwlock, FTAG);
1967 	if (birth > dsl_dataset_phys(snap)->ds_creation_txg) {
1968 		objset_t *os, *os_snap;
1969 		/*
1970 		 * It may be that only the ZIL differs, because it was
1971 		 * reset in the head.  Don't count that as being
1972 		 * modified.
1973 		 */
1974 		if (dmu_objset_from_ds(ds, &os) != 0)
1975 			return (B_TRUE);
1976 		if (dmu_objset_from_ds(snap, &os_snap) != 0)
1977 			return (B_TRUE);
1978 		return (bcmp(&os->os_phys->os_meta_dnode,
1979 		    &os_snap->os_phys->os_meta_dnode,
1980 		    sizeof (os->os_phys->os_meta_dnode)) != 0);
1981 	}
1982 	return (B_FALSE);
1983 }
1984 
1985 typedef struct dsl_dataset_rename_snapshot_arg {
1986 	const char *ddrsa_fsname;
1987 	const char *ddrsa_oldsnapname;
1988 	const char *ddrsa_newsnapname;
1989 	boolean_t ddrsa_recursive;
1990 	dmu_tx_t *ddrsa_tx;
1991 } dsl_dataset_rename_snapshot_arg_t;
1992 
1993 /* ARGSUSED */
1994 static int
1995 dsl_dataset_rename_snapshot_check_impl(dsl_pool_t *dp,
1996     dsl_dataset_t *hds, void *arg)
1997 {
1998 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1999 	int error;
2000 	uint64_t val;
2001 
2002 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
2003 	if (error != 0) {
2004 		/* ignore nonexistent snapshots */
2005 		return (error == ENOENT ? 0 : error);
2006 	}
2007 
2008 	/* new name should not exist */
2009 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_newsnapname, &val);
2010 	if (error == 0)
2011 		error = SET_ERROR(EEXIST);
2012 	else if (error == ENOENT)
2013 		error = 0;
2014 
2015 	/* dataset name + 1 for the "@" + the new snapshot name must fit */
2016 	if (dsl_dir_namelen(hds->ds_dir) + 1 +
2017 	    strlen(ddrsa->ddrsa_newsnapname) >= ZFS_MAX_DATASET_NAME_LEN)
2018 		error = SET_ERROR(ENAMETOOLONG);
2019 
2020 	return (error);
2021 }
2022 
2023 static int
2024 dsl_dataset_rename_snapshot_check(void *arg, dmu_tx_t *tx)
2025 {
2026 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2027 	dsl_pool_t *dp = dmu_tx_pool(tx);
2028 	dsl_dataset_t *hds;
2029 	int error;
2030 
2031 	error = dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds);
2032 	if (error != 0)
2033 		return (error);
2034 
2035 	if (ddrsa->ddrsa_recursive) {
2036 		error = dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
2037 		    dsl_dataset_rename_snapshot_check_impl, ddrsa,
2038 		    DS_FIND_CHILDREN);
2039 	} else {
2040 		error = dsl_dataset_rename_snapshot_check_impl(dp, hds, ddrsa);
2041 	}
2042 	dsl_dataset_rele(hds, FTAG);
2043 	return (error);
2044 }
2045 
2046 static int
2047 dsl_dataset_rename_snapshot_sync_impl(dsl_pool_t *dp,
2048     dsl_dataset_t *hds, void *arg)
2049 {
2050 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2051 	dsl_dataset_t *ds;
2052 	uint64_t val;
2053 	dmu_tx_t *tx = ddrsa->ddrsa_tx;
2054 	int error;
2055 
2056 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
2057 	ASSERT(error == 0 || error == ENOENT);
2058 	if (error == ENOENT) {
2059 		/* ignore nonexistent snapshots */
2060 		return (0);
2061 	}
2062 
2063 	VERIFY0(dsl_dataset_hold_obj(dp, val, FTAG, &ds));
2064 
2065 	/* log before we change the name */
2066 	spa_history_log_internal_ds(ds, "rename", tx,
2067 	    "-> @%s", ddrsa->ddrsa_newsnapname);
2068 
2069 	VERIFY0(dsl_dataset_snap_remove(hds, ddrsa->ddrsa_oldsnapname, tx,
2070 	    B_FALSE));
2071 	mutex_enter(&ds->ds_lock);
2072 	(void) strcpy(ds->ds_snapname, ddrsa->ddrsa_newsnapname);
2073 	mutex_exit(&ds->ds_lock);
2074 	VERIFY0(zap_add(dp->dp_meta_objset,
2075 	    dsl_dataset_phys(hds)->ds_snapnames_zapobj,
2076 	    ds->ds_snapname, 8, 1, &ds->ds_object, tx));
2077 
2078 	dsl_dataset_rele(ds, FTAG);
2079 	return (0);
2080 }
2081 
2082 static void
2083 dsl_dataset_rename_snapshot_sync(void *arg, dmu_tx_t *tx)
2084 {
2085 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2086 	dsl_pool_t *dp = dmu_tx_pool(tx);
2087 	dsl_dataset_t *hds;
2088 
2089 	VERIFY0(dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds));
2090 	ddrsa->ddrsa_tx = tx;
2091 	if (ddrsa->ddrsa_recursive) {
2092 		VERIFY0(dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
2093 		    dsl_dataset_rename_snapshot_sync_impl, ddrsa,
2094 		    DS_FIND_CHILDREN));
2095 	} else {
2096 		VERIFY0(dsl_dataset_rename_snapshot_sync_impl(dp, hds, ddrsa));
2097 	}
2098 	dsl_dataset_rele(hds, FTAG);
2099 }
2100 
2101 int
2102 dsl_dataset_rename_snapshot(const char *fsname,
2103     const char *oldsnapname, const char *newsnapname, boolean_t recursive)
2104 {
2105 	dsl_dataset_rename_snapshot_arg_t ddrsa;
2106 
2107 	ddrsa.ddrsa_fsname = fsname;
2108 	ddrsa.ddrsa_oldsnapname = oldsnapname;
2109 	ddrsa.ddrsa_newsnapname = newsnapname;
2110 	ddrsa.ddrsa_recursive = recursive;
2111 
2112 	return (dsl_sync_task(fsname, dsl_dataset_rename_snapshot_check,
2113 	    dsl_dataset_rename_snapshot_sync, &ddrsa,
2114 	    1, ZFS_SPACE_CHECK_RESERVED));
2115 }
2116 
2117 /*
2118  * If we're doing an ownership handoff, we need to make sure that there is
2119  * only one long hold on the dataset.  We're not allowed to change anything here
2120  * so we don't permanently release the long hold or regular hold here.  We want
2121  * to do this only when syncing to avoid the dataset unexpectedly going away
2122  * when we release the long hold.
2123  */
2124 static int
2125 dsl_dataset_handoff_check(dsl_dataset_t *ds, void *owner, dmu_tx_t *tx)
2126 {
2127 	boolean_t held;
2128 
2129 	if (!dmu_tx_is_syncing(tx))
2130 		return (0);
2131 
2132 	if (owner != NULL) {
2133 		VERIFY3P(ds->ds_owner, ==, owner);
2134 		dsl_dataset_long_rele(ds, owner);
2135 	}
2136 
2137 	held = dsl_dataset_long_held(ds);
2138 
2139 	if (owner != NULL)
2140 		dsl_dataset_long_hold(ds, owner);
2141 
2142 	if (held)
2143 		return (SET_ERROR(EBUSY));
2144 
2145 	return (0);
2146 }
2147 
2148 typedef struct dsl_dataset_rollback_arg {
2149 	const char *ddra_fsname;
2150 	void *ddra_owner;
2151 	nvlist_t *ddra_result;
2152 } dsl_dataset_rollback_arg_t;
2153 
2154 static int
2155 dsl_dataset_rollback_check(void *arg, dmu_tx_t *tx)
2156 {
2157 	dsl_dataset_rollback_arg_t *ddra = arg;
2158 	dsl_pool_t *dp = dmu_tx_pool(tx);
2159 	dsl_dataset_t *ds;
2160 	int64_t unused_refres_delta;
2161 	int error;
2162 
2163 	error = dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds);
2164 	if (error != 0)
2165 		return (error);
2166 
2167 	/* must not be a snapshot */
2168 	if (ds->ds_is_snapshot) {
2169 		dsl_dataset_rele(ds, FTAG);
2170 		return (SET_ERROR(EINVAL));
2171 	}
2172 
2173 	/* must have a most recent snapshot */
2174 	if (dsl_dataset_phys(ds)->ds_prev_snap_txg < TXG_INITIAL) {
2175 		dsl_dataset_rele(ds, FTAG);
2176 		return (SET_ERROR(EINVAL));
2177 	}
2178 
2179 	/* must not have any bookmarks after the most recent snapshot */
2180 	nvlist_t *proprequest = fnvlist_alloc();
2181 	fnvlist_add_boolean(proprequest, zfs_prop_to_name(ZFS_PROP_CREATETXG));
2182 	nvlist_t *bookmarks = fnvlist_alloc();
2183 	error = dsl_get_bookmarks_impl(ds, proprequest, bookmarks);
2184 	fnvlist_free(proprequest);
2185 	if (error != 0)
2186 		return (error);
2187 	for (nvpair_t *pair = nvlist_next_nvpair(bookmarks, NULL);
2188 	    pair != NULL; pair = nvlist_next_nvpair(bookmarks, pair)) {
2189 		nvlist_t *valuenv =
2190 		    fnvlist_lookup_nvlist(fnvpair_value_nvlist(pair),
2191 		    zfs_prop_to_name(ZFS_PROP_CREATETXG));
2192 		uint64_t createtxg = fnvlist_lookup_uint64(valuenv, "value");
2193 		if (createtxg > dsl_dataset_phys(ds)->ds_prev_snap_txg) {
2194 			fnvlist_free(bookmarks);
2195 			dsl_dataset_rele(ds, FTAG);
2196 			return (SET_ERROR(EEXIST));
2197 		}
2198 	}
2199 	fnvlist_free(bookmarks);
2200 
2201 	error = dsl_dataset_handoff_check(ds, ddra->ddra_owner, tx);
2202 	if (error != 0) {
2203 		dsl_dataset_rele(ds, FTAG);
2204 		return (error);
2205 	}
2206 
2207 	/*
2208 	 * Check if the snap we are rolling back to uses more than
2209 	 * the refquota.
2210 	 */
2211 	if (ds->ds_quota != 0 &&
2212 	    dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes > ds->ds_quota) {
2213 		dsl_dataset_rele(ds, FTAG);
2214 		return (SET_ERROR(EDQUOT));
2215 	}
2216 
2217 	/*
2218 	 * When we do the clone swap, we will temporarily use more space
2219 	 * due to the refreservation (the head will no longer have any
2220 	 * unique space, so the entire amount of the refreservation will need
2221 	 * to be free).  We will immediately destroy the clone, freeing
2222 	 * this space, but the freeing happens over many txg's.
2223 	 */
2224 	unused_refres_delta = (int64_t)MIN(ds->ds_reserved,
2225 	    dsl_dataset_phys(ds)->ds_unique_bytes);
2226 
2227 	if (unused_refres_delta > 0 &&
2228 	    unused_refres_delta >
2229 	    dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) {
2230 		dsl_dataset_rele(ds, FTAG);
2231 		return (SET_ERROR(ENOSPC));
2232 	}
2233 
2234 	dsl_dataset_rele(ds, FTAG);
2235 	return (0);
2236 }
2237 
2238 static void
2239 dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
2240 {
2241 	dsl_dataset_rollback_arg_t *ddra = arg;
2242 	dsl_pool_t *dp = dmu_tx_pool(tx);
2243 	dsl_dataset_t *ds, *clone;
2244 	uint64_t cloneobj;
2245 	char namebuf[ZFS_MAX_DATASET_NAME_LEN];
2246 
2247 	VERIFY0(dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds));
2248 
2249 	dsl_dataset_name(ds->ds_prev, namebuf);
2250 	fnvlist_add_string(ddra->ddra_result, "target", namebuf);
2251 
2252 	cloneobj = dsl_dataset_create_sync(ds->ds_dir, "%rollback",
2253 	    ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, tx);
2254 
2255 	VERIFY0(dsl_dataset_hold_obj(dp, cloneobj, FTAG, &clone));
2256 
2257 	dsl_dataset_clone_swap_sync_impl(clone, ds, tx);
2258 	dsl_dataset_zero_zil(ds, tx);
2259 
2260 	dsl_destroy_head_sync_impl(clone, tx);
2261 
2262 	dsl_dataset_rele(clone, FTAG);
2263 	dsl_dataset_rele(ds, FTAG);
2264 }
2265 
2266 /*
2267  * Rolls back the given filesystem or volume to the most recent snapshot.
2268  * The name of the most recent snapshot will be returned under key "target"
2269  * in the result nvlist.
2270  *
2271  * If owner != NULL:
2272  * - The existing dataset MUST be owned by the specified owner at entry
2273  * - Upon return, dataset will still be held by the same owner, whether we
2274  *   succeed or not.
2275  *
2276  * This mode is required any time the existing filesystem is mounted.  See
2277  * notes above zfs_suspend_fs() for further details.
2278  */
2279 int
2280 dsl_dataset_rollback(const char *fsname, void *owner, nvlist_t *result)
2281 {
2282 	dsl_dataset_rollback_arg_t ddra;
2283 
2284 	ddra.ddra_fsname = fsname;
2285 	ddra.ddra_owner = owner;
2286 	ddra.ddra_result = result;
2287 
2288 	return (dsl_sync_task(fsname, dsl_dataset_rollback_check,
2289 	    dsl_dataset_rollback_sync, &ddra,
2290 	    1, ZFS_SPACE_CHECK_RESERVED));
2291 }
2292 
2293 struct promotenode {
2294 	list_node_t link;
2295 	dsl_dataset_t *ds;
2296 };
2297 
2298 typedef struct dsl_dataset_promote_arg {
2299 	const char *ddpa_clonename;
2300 	dsl_dataset_t *ddpa_clone;
2301 	list_t shared_snaps, origin_snaps, clone_snaps;
2302 	dsl_dataset_t *origin_origin; /* origin of the origin */
2303 	uint64_t used, comp, uncomp, unique, cloneusedsnap, originusedsnap;
2304 	char *err_ds;
2305 	cred_t *cr;
2306 } dsl_dataset_promote_arg_t;
2307 
2308 static int snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep);
2309 static int promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp,
2310     void *tag);
2311 static void promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag);
2312 
2313 static int
2314 dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
2315 {
2316 	dsl_dataset_promote_arg_t *ddpa = arg;
2317 	dsl_pool_t *dp = dmu_tx_pool(tx);
2318 	dsl_dataset_t *hds;
2319 	struct promotenode *snap;
2320 	dsl_dataset_t *origin_ds;
2321 	int err;
2322 	uint64_t unused;
2323 	uint64_t ss_mv_cnt;
2324 	size_t max_snap_len;
2325 
2326 	err = promote_hold(ddpa, dp, FTAG);
2327 	if (err != 0)
2328 		return (err);
2329 
2330 	hds = ddpa->ddpa_clone;
2331 	max_snap_len = MAXNAMELEN - strlen(ddpa->ddpa_clonename) - 1;
2332 
2333 	if (dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE) {
2334 		promote_rele(ddpa, FTAG);
2335 		return (SET_ERROR(EXDEV));
2336 	}
2337 
2338 	/*
2339 	 * Compute and check the amount of space to transfer.  Since this is
2340 	 * so expensive, don't do the preliminary check.
2341 	 */
2342 	if (!dmu_tx_is_syncing(tx)) {
2343 		promote_rele(ddpa, FTAG);
2344 		return (0);
2345 	}
2346 
2347 	snap = list_head(&ddpa->shared_snaps);
2348 	origin_ds = snap->ds;
2349 
2350 	/* compute origin's new unique space */
2351 	snap = list_tail(&ddpa->clone_snaps);
2352 	ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
2353 	    origin_ds->ds_object);
2354 	dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2355 	    dsl_dataset_phys(origin_ds)->ds_prev_snap_txg, UINT64_MAX,
2356 	    &ddpa->unique, &unused, &unused);
2357 
2358 	/*
2359 	 * Walk the snapshots that we are moving
2360 	 *
2361 	 * Compute space to transfer.  Consider the incremental changes
2362 	 * to used by each snapshot:
2363 	 * (my used) = (prev's used) + (blocks born) - (blocks killed)
2364 	 * So each snapshot gave birth to:
2365 	 * (blocks born) = (my used) - (prev's used) + (blocks killed)
2366 	 * So a sequence would look like:
2367 	 * (uN - u(N-1) + kN) + ... + (u1 - u0 + k1) + (u0 - 0 + k0)
2368 	 * Which simplifies to:
2369 	 * uN + kN + kN-1 + ... + k1 + k0
2370 	 * Note however, if we stop before we reach the ORIGIN we get:
2371 	 * uN + kN + kN-1 + ... + kM - uM-1
2372 	 */
2373 	ss_mv_cnt = 0;
2374 	ddpa->used = dsl_dataset_phys(origin_ds)->ds_referenced_bytes;
2375 	ddpa->comp = dsl_dataset_phys(origin_ds)->ds_compressed_bytes;
2376 	ddpa->uncomp = dsl_dataset_phys(origin_ds)->ds_uncompressed_bytes;
2377 	for (snap = list_head(&ddpa->shared_snaps); snap;
2378 	    snap = list_next(&ddpa->shared_snaps, snap)) {
2379 		uint64_t val, dlused, dlcomp, dluncomp;
2380 		dsl_dataset_t *ds = snap->ds;
2381 
2382 		ss_mv_cnt++;
2383 
2384 		/*
2385 		 * If there are long holds, we won't be able to evict
2386 		 * the objset.
2387 		 */
2388 		if (dsl_dataset_long_held(ds)) {
2389 			err = SET_ERROR(EBUSY);
2390 			goto out;
2391 		}
2392 
2393 		/* Check that the snapshot name does not conflict */
2394 		VERIFY0(dsl_dataset_get_snapname(ds));
2395 		if (strlen(ds->ds_snapname) >= max_snap_len) {
2396 			err = SET_ERROR(ENAMETOOLONG);
2397 			goto out;
2398 		}
2399 		err = dsl_dataset_snap_lookup(hds, ds->ds_snapname, &val);
2400 		if (err == 0) {
2401 			(void) strcpy(ddpa->err_ds, snap->ds->ds_snapname);
2402 			err = SET_ERROR(EEXIST);
2403 			goto out;
2404 		}
2405 		if (err != ENOENT)
2406 			goto out;
2407 
2408 		/* The very first snapshot does not have a deadlist */
2409 		if (dsl_dataset_phys(ds)->ds_prev_snap_obj == 0)
2410 			continue;
2411 
2412 		dsl_deadlist_space(&ds->ds_deadlist,
2413 		    &dlused, &dlcomp, &dluncomp);
2414 		ddpa->used += dlused;
2415 		ddpa->comp += dlcomp;
2416 		ddpa->uncomp += dluncomp;
2417 	}
2418 
2419 	/*
2420 	 * If we are a clone of a clone then we never reached ORIGIN,
2421 	 * so we need to subtract out the clone origin's used space.
2422 	 */
2423 	if (ddpa->origin_origin) {
2424 		ddpa->used -=
2425 		    dsl_dataset_phys(ddpa->origin_origin)->ds_referenced_bytes;
2426 		ddpa->comp -=
2427 		    dsl_dataset_phys(ddpa->origin_origin)->ds_compressed_bytes;
2428 		ddpa->uncomp -=
2429 		    dsl_dataset_phys(ddpa->origin_origin)->
2430 		    ds_uncompressed_bytes;
2431 	}
2432 
2433 	/* Check that there is enough space and limit headroom here */
2434 	err = dsl_dir_transfer_possible(origin_ds->ds_dir, hds->ds_dir,
2435 	    0, ss_mv_cnt, ddpa->used, ddpa->cr);
2436 	if (err != 0)
2437 		goto out;
2438 
2439 	/*
2440 	 * Compute the amounts of space that will be used by snapshots
2441 	 * after the promotion (for both origin and clone).  For each,
2442 	 * it is the amount of space that will be on all of their
2443 	 * deadlists (that was not born before their new origin).
2444 	 */
2445 	if (dsl_dir_phys(hds->ds_dir)->dd_flags & DD_FLAG_USED_BREAKDOWN) {
2446 		uint64_t space;
2447 
2448 		/*
2449 		 * Note, typically this will not be a clone of a clone,
2450 		 * so dd_origin_txg will be < TXG_INITIAL, so
2451 		 * these snaplist_space() -> dsl_deadlist_space_range()
2452 		 * calls will be fast because they do not have to
2453 		 * iterate over all bps.
2454 		 */
2455 		snap = list_head(&ddpa->origin_snaps);
2456 		err = snaplist_space(&ddpa->shared_snaps,
2457 		    snap->ds->ds_dir->dd_origin_txg, &ddpa->cloneusedsnap);
2458 		if (err != 0)
2459 			goto out;
2460 
2461 		err = snaplist_space(&ddpa->clone_snaps,
2462 		    snap->ds->ds_dir->dd_origin_txg, &space);
2463 		if (err != 0)
2464 			goto out;
2465 		ddpa->cloneusedsnap += space;
2466 	}
2467 	if (dsl_dir_phys(origin_ds->ds_dir)->dd_flags &
2468 	    DD_FLAG_USED_BREAKDOWN) {
2469 		err = snaplist_space(&ddpa->origin_snaps,
2470 		    dsl_dataset_phys(origin_ds)->ds_creation_txg,
2471 		    &ddpa->originusedsnap);
2472 		if (err != 0)
2473 			goto out;
2474 	}
2475 
2476 out:
2477 	promote_rele(ddpa, FTAG);
2478 	return (err);
2479 }
2480 
2481 static void
2482 dsl_dataset_promote_sync(void *arg, dmu_tx_t *tx)
2483 {
2484 	dsl_dataset_promote_arg_t *ddpa = arg;
2485 	dsl_pool_t *dp = dmu_tx_pool(tx);
2486 	dsl_dataset_t *hds;
2487 	struct promotenode *snap;
2488 	dsl_dataset_t *origin_ds;
2489 	dsl_dataset_t *origin_head;
2490 	dsl_dir_t *dd;
2491 	dsl_dir_t *odd = NULL;
2492 	uint64_t oldnext_obj;
2493 	int64_t delta;
2494 
2495 	VERIFY0(promote_hold(ddpa, dp, FTAG));
2496 	hds = ddpa->ddpa_clone;
2497 
2498 	ASSERT0(dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE);
2499 
2500 	snap = list_head(&ddpa->shared_snaps);
2501 	origin_ds = snap->ds;
2502 	dd = hds->ds_dir;
2503 
2504 	snap = list_head(&ddpa->origin_snaps);
2505 	origin_head = snap->ds;
2506 
2507 	/*
2508 	 * We need to explicitly open odd, since origin_ds's dd will be
2509 	 * changing.
2510 	 */
2511 	VERIFY0(dsl_dir_hold_obj(dp, origin_ds->ds_dir->dd_object,
2512 	    NULL, FTAG, &odd));
2513 
2514 	/* change origin's next snap */
2515 	dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
2516 	oldnext_obj = dsl_dataset_phys(origin_ds)->ds_next_snap_obj;
2517 	snap = list_tail(&ddpa->clone_snaps);
2518 	ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
2519 	    origin_ds->ds_object);
2520 	dsl_dataset_phys(origin_ds)->ds_next_snap_obj = snap->ds->ds_object;
2521 
2522 	/* change the origin's next clone */
2523 	if (dsl_dataset_phys(origin_ds)->ds_next_clones_obj) {
2524 		dsl_dataset_remove_from_next_clones(origin_ds,
2525 		    snap->ds->ds_object, tx);
2526 		VERIFY0(zap_add_int(dp->dp_meta_objset,
2527 		    dsl_dataset_phys(origin_ds)->ds_next_clones_obj,
2528 		    oldnext_obj, tx));
2529 	}
2530 
2531 	/* change origin */
2532 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
2533 	ASSERT3U(dsl_dir_phys(dd)->dd_origin_obj, ==, origin_ds->ds_object);
2534 	dsl_dir_phys(dd)->dd_origin_obj = dsl_dir_phys(odd)->dd_origin_obj;
2535 	dd->dd_origin_txg = origin_head->ds_dir->dd_origin_txg;
2536 	dmu_buf_will_dirty(odd->dd_dbuf, tx);
2537 	dsl_dir_phys(odd)->dd_origin_obj = origin_ds->ds_object;
2538 	origin_head->ds_dir->dd_origin_txg =
2539 	    dsl_dataset_phys(origin_ds)->ds_creation_txg;
2540 
2541 	/* change dd_clone entries */
2542 	if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2543 		VERIFY0(zap_remove_int(dp->dp_meta_objset,
2544 		    dsl_dir_phys(odd)->dd_clones, hds->ds_object, tx));
2545 		VERIFY0(zap_add_int(dp->dp_meta_objset,
2546 		    dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
2547 		    hds->ds_object, tx));
2548 
2549 		VERIFY0(zap_remove_int(dp->dp_meta_objset,
2550 		    dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
2551 		    origin_head->ds_object, tx));
2552 		if (dsl_dir_phys(dd)->dd_clones == 0) {
2553 			dsl_dir_phys(dd)->dd_clones =
2554 			    zap_create(dp->dp_meta_objset, DMU_OT_DSL_CLONES,
2555 			    DMU_OT_NONE, 0, tx);
2556 		}
2557 		VERIFY0(zap_add_int(dp->dp_meta_objset,
2558 		    dsl_dir_phys(dd)->dd_clones, origin_head->ds_object, tx));
2559 	}
2560 
2561 	/* move snapshots to this dir */
2562 	for (snap = list_head(&ddpa->shared_snaps); snap;
2563 	    snap = list_next(&ddpa->shared_snaps, snap)) {
2564 		dsl_dataset_t *ds = snap->ds;
2565 
2566 		/*
2567 		 * Property callbacks are registered to a particular
2568 		 * dsl_dir.  Since ours is changing, evict the objset
2569 		 * so that they will be unregistered from the old dsl_dir.
2570 		 */
2571 		if (ds->ds_objset) {
2572 			dmu_objset_evict(ds->ds_objset);
2573 			ds->ds_objset = NULL;
2574 		}
2575 
2576 		/* move snap name entry */
2577 		VERIFY0(dsl_dataset_get_snapname(ds));
2578 		VERIFY0(dsl_dataset_snap_remove(origin_head,
2579 		    ds->ds_snapname, tx, B_TRUE));
2580 		VERIFY0(zap_add(dp->dp_meta_objset,
2581 		    dsl_dataset_phys(hds)->ds_snapnames_zapobj, ds->ds_snapname,
2582 		    8, 1, &ds->ds_object, tx));
2583 		dsl_fs_ss_count_adjust(hds->ds_dir, 1,
2584 		    DD_FIELD_SNAPSHOT_COUNT, tx);
2585 
2586 		/* change containing dsl_dir */
2587 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
2588 		ASSERT3U(dsl_dataset_phys(ds)->ds_dir_obj, ==, odd->dd_object);
2589 		dsl_dataset_phys(ds)->ds_dir_obj = dd->dd_object;
2590 		ASSERT3P(ds->ds_dir, ==, odd);
2591 		dsl_dir_rele(ds->ds_dir, ds);
2592 		VERIFY0(dsl_dir_hold_obj(dp, dd->dd_object,
2593 		    NULL, ds, &ds->ds_dir));
2594 
2595 		/* move any clone references */
2596 		if (dsl_dataset_phys(ds)->ds_next_clones_obj &&
2597 		    spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2598 			zap_cursor_t zc;
2599 			zap_attribute_t za;
2600 
2601 			for (zap_cursor_init(&zc, dp->dp_meta_objset,
2602 			    dsl_dataset_phys(ds)->ds_next_clones_obj);
2603 			    zap_cursor_retrieve(&zc, &za) == 0;
2604 			    zap_cursor_advance(&zc)) {
2605 				dsl_dataset_t *cnds;
2606 				uint64_t o;
2607 
2608 				if (za.za_first_integer == oldnext_obj) {
2609 					/*
2610 					 * We've already moved the
2611 					 * origin's reference.
2612 					 */
2613 					continue;
2614 				}
2615 
2616 				VERIFY0(dsl_dataset_hold_obj(dp,
2617 				    za.za_first_integer, FTAG, &cnds));
2618 				o = dsl_dir_phys(cnds->ds_dir)->
2619 				    dd_head_dataset_obj;
2620 
2621 				VERIFY0(zap_remove_int(dp->dp_meta_objset,
2622 				    dsl_dir_phys(odd)->dd_clones, o, tx));
2623 				VERIFY0(zap_add_int(dp->dp_meta_objset,
2624 				    dsl_dir_phys(dd)->dd_clones, o, tx));
2625 				dsl_dataset_rele(cnds, FTAG);
2626 			}
2627 			zap_cursor_fini(&zc);
2628 		}
2629 
2630 		ASSERT(!dsl_prop_hascb(ds));
2631 	}
2632 
2633 	/*
2634 	 * Change space accounting.
2635 	 * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either
2636 	 * both be valid, or both be 0 (resulting in delta == 0).  This
2637 	 * is true for each of {clone,origin} independently.
2638 	 */
2639 
2640 	delta = ddpa->cloneusedsnap -
2641 	    dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_SNAP];
2642 	ASSERT3S(delta, >=, 0);
2643 	ASSERT3U(ddpa->used, >=, delta);
2644 	dsl_dir_diduse_space(dd, DD_USED_SNAP, delta, 0, 0, tx);
2645 	dsl_dir_diduse_space(dd, DD_USED_HEAD,
2646 	    ddpa->used - delta, ddpa->comp, ddpa->uncomp, tx);
2647 
2648 	delta = ddpa->originusedsnap -
2649 	    dsl_dir_phys(odd)->dd_used_breakdown[DD_USED_SNAP];
2650 	ASSERT3S(delta, <=, 0);
2651 	ASSERT3U(ddpa->used, >=, -delta);
2652 	dsl_dir_diduse_space(odd, DD_USED_SNAP, delta, 0, 0, tx);
2653 	dsl_dir_diduse_space(odd, DD_USED_HEAD,
2654 	    -ddpa->used - delta, -ddpa->comp, -ddpa->uncomp, tx);
2655 
2656 	dsl_dataset_phys(origin_ds)->ds_unique_bytes = ddpa->unique;
2657 
2658 	/* log history record */
2659 	spa_history_log_internal_ds(hds, "promote", tx, "");
2660 
2661 	dsl_dir_rele(odd, FTAG);
2662 	promote_rele(ddpa, FTAG);
2663 }
2664 
2665 /*
2666  * Make a list of dsl_dataset_t's for the snapshots between first_obj
2667  * (exclusive) and last_obj (inclusive).  The list will be in reverse
2668  * order (last_obj will be the list_head()).  If first_obj == 0, do all
2669  * snapshots back to this dataset's origin.
2670  */
2671 static int
2672 snaplist_make(dsl_pool_t *dp,
2673     uint64_t first_obj, uint64_t last_obj, list_t *l, void *tag)
2674 {
2675 	uint64_t obj = last_obj;
2676 
2677 	list_create(l, sizeof (struct promotenode),
2678 	    offsetof(struct promotenode, link));
2679 
2680 	while (obj != first_obj) {
2681 		dsl_dataset_t *ds;
2682 		struct promotenode *snap;
2683 		int err;
2684 
2685 		err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
2686 		ASSERT(err != ENOENT);
2687 		if (err != 0)
2688 			return (err);
2689 
2690 		if (first_obj == 0)
2691 			first_obj = dsl_dir_phys(ds->ds_dir)->dd_origin_obj;
2692 
2693 		snap = kmem_alloc(sizeof (*snap), KM_SLEEP);
2694 		snap->ds = ds;
2695 		list_insert_tail(l, snap);
2696 		obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
2697 	}
2698 
2699 	return (0);
2700 }
2701 
2702 static int
2703 snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep)
2704 {
2705 	struct promotenode *snap;
2706 
2707 	*spacep = 0;
2708 	for (snap = list_head(l); snap; snap = list_next(l, snap)) {
2709 		uint64_t used, comp, uncomp;
2710 		dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2711 		    mintxg, UINT64_MAX, &used, &comp, &uncomp);
2712 		*spacep += used;
2713 	}
2714 	return (0);
2715 }
2716 
2717 static void
2718 snaplist_destroy(list_t *l, void *tag)
2719 {
2720 	struct promotenode *snap;
2721 
2722 	if (l == NULL || !list_link_active(&l->list_head))
2723 		return;
2724 
2725 	while ((snap = list_tail(l)) != NULL) {
2726 		list_remove(l, snap);
2727 		dsl_dataset_rele(snap->ds, tag);
2728 		kmem_free(snap, sizeof (*snap));
2729 	}
2730 	list_destroy(l);
2731 }
2732 
2733 static int
2734 promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp, void *tag)
2735 {
2736 	int error;
2737 	dsl_dir_t *dd;
2738 	struct promotenode *snap;
2739 
2740 	error = dsl_dataset_hold(dp, ddpa->ddpa_clonename, tag,
2741 	    &ddpa->ddpa_clone);
2742 	if (error != 0)
2743 		return (error);
2744 	dd = ddpa->ddpa_clone->ds_dir;
2745 
2746 	if (ddpa->ddpa_clone->ds_is_snapshot ||
2747 	    !dsl_dir_is_clone(dd)) {
2748 		dsl_dataset_rele(ddpa->ddpa_clone, tag);
2749 		return (SET_ERROR(EINVAL));
2750 	}
2751 
2752 	error = snaplist_make(dp, 0, dsl_dir_phys(dd)->dd_origin_obj,
2753 	    &ddpa->shared_snaps, tag);
2754 	if (error != 0)
2755 		goto out;
2756 
2757 	error = snaplist_make(dp, 0, ddpa->ddpa_clone->ds_object,
2758 	    &ddpa->clone_snaps, tag);
2759 	if (error != 0)
2760 		goto out;
2761 
2762 	snap = list_head(&ddpa->shared_snaps);
2763 	ASSERT3U(snap->ds->ds_object, ==, dsl_dir_phys(dd)->dd_origin_obj);
2764 	error = snaplist_make(dp, dsl_dir_phys(dd)->dd_origin_obj,
2765 	    dsl_dir_phys(snap->ds->ds_dir)->dd_head_dataset_obj,
2766 	    &ddpa->origin_snaps, tag);
2767 	if (error != 0)
2768 		goto out;
2769 
2770 	if (dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj != 0) {
2771 		error = dsl_dataset_hold_obj(dp,
2772 		    dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj,
2773 		    tag, &ddpa->origin_origin);
2774 		if (error != 0)
2775 			goto out;
2776 	}
2777 out:
2778 	if (error != 0)
2779 		promote_rele(ddpa, tag);
2780 	return (error);
2781 }
2782 
2783 static void
2784 promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag)
2785 {
2786 	snaplist_destroy(&ddpa->shared_snaps, tag);
2787 	snaplist_destroy(&ddpa->clone_snaps, tag);
2788 	snaplist_destroy(&ddpa->origin_snaps, tag);
2789 	if (ddpa->origin_origin != NULL)
2790 		dsl_dataset_rele(ddpa->origin_origin, tag);
2791 	dsl_dataset_rele(ddpa->ddpa_clone, tag);
2792 }
2793 
2794 /*
2795  * Promote a clone.
2796  *
2797  * If it fails due to a conflicting snapshot name, "conflsnap" will be filled
2798  * in with the name.  (It must be at least ZFS_MAX_DATASET_NAME_LEN bytes long.)
2799  */
2800 int
2801 dsl_dataset_promote(const char *name, char *conflsnap)
2802 {
2803 	dsl_dataset_promote_arg_t ddpa = { 0 };
2804 	uint64_t numsnaps;
2805 	int error;
2806 	objset_t *os;
2807 
2808 	/*
2809 	 * We will modify space proportional to the number of
2810 	 * snapshots.  Compute numsnaps.
2811 	 */
2812 	error = dmu_objset_hold(name, FTAG, &os);
2813 	if (error != 0)
2814 		return (error);
2815 	error = zap_count(dmu_objset_pool(os)->dp_meta_objset,
2816 	    dsl_dataset_phys(dmu_objset_ds(os))->ds_snapnames_zapobj,
2817 	    &numsnaps);
2818 	dmu_objset_rele(os, FTAG);
2819 	if (error != 0)
2820 		return (error);
2821 
2822 	ddpa.ddpa_clonename = name;
2823 	ddpa.err_ds = conflsnap;
2824 	ddpa.cr = CRED();
2825 
2826 	return (dsl_sync_task(name, dsl_dataset_promote_check,
2827 	    dsl_dataset_promote_sync, &ddpa,
2828 	    2 + numsnaps, ZFS_SPACE_CHECK_RESERVED));
2829 }
2830 
2831 int
2832 dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
2833     dsl_dataset_t *origin_head, boolean_t force, void *owner, dmu_tx_t *tx)
2834 {
2835 	/*
2836 	 * "slack" factor for received datasets with refquota set on them.
2837 	 * See the bottom of this function for details on its use.
2838 	 */
2839 	uint64_t refquota_slack = DMU_MAX_ACCESS * spa_asize_inflation;
2840 	int64_t unused_refres_delta;
2841 
2842 	/* they should both be heads */
2843 	if (clone->ds_is_snapshot ||
2844 	    origin_head->ds_is_snapshot)
2845 		return (SET_ERROR(EINVAL));
2846 
2847 	/* if we are not forcing, the branch point should be just before them */
2848 	if (!force && clone->ds_prev != origin_head->ds_prev)
2849 		return (SET_ERROR(EINVAL));
2850 
2851 	/* clone should be the clone (unless they are unrelated) */
2852 	if (clone->ds_prev != NULL &&
2853 	    clone->ds_prev != clone->ds_dir->dd_pool->dp_origin_snap &&
2854 	    origin_head->ds_dir != clone->ds_prev->ds_dir)
2855 		return (SET_ERROR(EINVAL));
2856 
2857 	/* the clone should be a child of the origin */
2858 	if (clone->ds_dir->dd_parent != origin_head->ds_dir)
2859 		return (SET_ERROR(EINVAL));
2860 
2861 	/* origin_head shouldn't be modified unless 'force' */
2862 	if (!force &&
2863 	    dsl_dataset_modified_since_snap(origin_head, origin_head->ds_prev))
2864 		return (SET_ERROR(ETXTBSY));
2865 
2866 	/* origin_head should have no long holds (e.g. is not mounted) */
2867 	if (dsl_dataset_handoff_check(origin_head, owner, tx))
2868 		return (SET_ERROR(EBUSY));
2869 
2870 	/* check amount of any unconsumed refreservation */
2871 	unused_refres_delta =
2872 	    (int64_t)MIN(origin_head->ds_reserved,
2873 	    dsl_dataset_phys(origin_head)->ds_unique_bytes) -
2874 	    (int64_t)MIN(origin_head->ds_reserved,
2875 	    dsl_dataset_phys(clone)->ds_unique_bytes);
2876 
2877 	if (unused_refres_delta > 0 &&
2878 	    unused_refres_delta >
2879 	    dsl_dir_space_available(origin_head->ds_dir, NULL, 0, TRUE))
2880 		return (SET_ERROR(ENOSPC));
2881 
2882 	/*
2883 	 * The clone can't be too much over the head's refquota.
2884 	 *
2885 	 * To ensure that the entire refquota can be used, we allow one
2886 	 * transaction to exceed the the refquota.  Therefore, this check
2887 	 * needs to also allow for the space referenced to be more than the
2888 	 * refquota.  The maximum amount of space that one transaction can use
2889 	 * on disk is DMU_MAX_ACCESS * spa_asize_inflation.  Allowing this
2890 	 * overage ensures that we are able to receive a filesystem that
2891 	 * exceeds the refquota on the source system.
2892 	 *
2893 	 * So that overage is the refquota_slack we use below.
2894 	 */
2895 	if (origin_head->ds_quota != 0 &&
2896 	    dsl_dataset_phys(clone)->ds_referenced_bytes >
2897 	    origin_head->ds_quota + refquota_slack)
2898 		return (SET_ERROR(EDQUOT));
2899 
2900 	return (0);
2901 }
2902 
2903 void
2904 dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
2905     dsl_dataset_t *origin_head, dmu_tx_t *tx)
2906 {
2907 	dsl_pool_t *dp = dmu_tx_pool(tx);
2908 	int64_t unused_refres_delta;
2909 
2910 	ASSERT(clone->ds_reserved == 0);
2911 	/*
2912 	 * NOTE: On DEBUG kernels there could be a race between this and
2913 	 * the check function if spa_asize_inflation is adjusted...
2914 	 */
2915 	ASSERT(origin_head->ds_quota == 0 ||
2916 	    dsl_dataset_phys(clone)->ds_unique_bytes <= origin_head->ds_quota +
2917 	    DMU_MAX_ACCESS * spa_asize_inflation);
2918 	ASSERT3P(clone->ds_prev, ==, origin_head->ds_prev);
2919 
2920 	/*
2921 	 * Swap per-dataset feature flags.
2922 	 */
2923 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
2924 		if (!(spa_feature_table[f].fi_flags &
2925 		    ZFEATURE_FLAG_PER_DATASET)) {
2926 			ASSERT(!clone->ds_feature_inuse[f]);
2927 			ASSERT(!origin_head->ds_feature_inuse[f]);
2928 			continue;
2929 		}
2930 
2931 		boolean_t clone_inuse = clone->ds_feature_inuse[f];
2932 		boolean_t origin_head_inuse = origin_head->ds_feature_inuse[f];
2933 
2934 		if (clone_inuse) {
2935 			dsl_dataset_deactivate_feature(clone->ds_object, f, tx);
2936 			clone->ds_feature_inuse[f] = B_FALSE;
2937 		}
2938 		if (origin_head_inuse) {
2939 			dsl_dataset_deactivate_feature(origin_head->ds_object,
2940 			    f, tx);
2941 			origin_head->ds_feature_inuse[f] = B_FALSE;
2942 		}
2943 		if (clone_inuse) {
2944 			dsl_dataset_activate_feature(origin_head->ds_object,
2945 			    f, tx);
2946 			origin_head->ds_feature_inuse[f] = B_TRUE;
2947 		}
2948 		if (origin_head_inuse) {
2949 			dsl_dataset_activate_feature(clone->ds_object, f, tx);
2950 			clone->ds_feature_inuse[f] = B_TRUE;
2951 		}
2952 	}
2953 
2954 	dmu_buf_will_dirty(clone->ds_dbuf, tx);
2955 	dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
2956 
2957 	if (clone->ds_objset != NULL) {
2958 		dmu_objset_evict(clone->ds_objset);
2959 		clone->ds_objset = NULL;
2960 	}
2961 
2962 	if (origin_head->ds_objset != NULL) {
2963 		dmu_objset_evict(origin_head->ds_objset);
2964 		origin_head->ds_objset = NULL;
2965 	}
2966 
2967 	unused_refres_delta =
2968 	    (int64_t)MIN(origin_head->ds_reserved,
2969 	    dsl_dataset_phys(origin_head)->ds_unique_bytes) -
2970 	    (int64_t)MIN(origin_head->ds_reserved,
2971 	    dsl_dataset_phys(clone)->ds_unique_bytes);
2972 
2973 	/*
2974 	 * Reset origin's unique bytes, if it exists.
2975 	 */
2976 	if (clone->ds_prev) {
2977 		dsl_dataset_t *origin = clone->ds_prev;
2978 		uint64_t comp, uncomp;
2979 
2980 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
2981 		dsl_deadlist_space_range(&clone->ds_deadlist,
2982 		    dsl_dataset_phys(origin)->ds_prev_snap_txg, UINT64_MAX,
2983 		    &dsl_dataset_phys(origin)->ds_unique_bytes, &comp, &uncomp);
2984 	}
2985 
2986 	/* swap blkptrs */
2987 	{
2988 		rrw_enter(&clone->ds_bp_rwlock, RW_WRITER, FTAG);
2989 		rrw_enter(&origin_head->ds_bp_rwlock, RW_WRITER, FTAG);
2990 		blkptr_t tmp;
2991 		tmp = dsl_dataset_phys(origin_head)->ds_bp;
2992 		dsl_dataset_phys(origin_head)->ds_bp =
2993 		    dsl_dataset_phys(clone)->ds_bp;
2994 		dsl_dataset_phys(clone)->ds_bp = tmp;
2995 		rrw_exit(&origin_head->ds_bp_rwlock, FTAG);
2996 		rrw_exit(&clone->ds_bp_rwlock, FTAG);
2997 	}
2998 
2999 	/* set dd_*_bytes */
3000 	{
3001 		int64_t dused, dcomp, duncomp;
3002 		uint64_t cdl_used, cdl_comp, cdl_uncomp;
3003 		uint64_t odl_used, odl_comp, odl_uncomp;
3004 
3005 		ASSERT3U(dsl_dir_phys(clone->ds_dir)->
3006 		    dd_used_breakdown[DD_USED_SNAP], ==, 0);
3007 
3008 		dsl_deadlist_space(&clone->ds_deadlist,
3009 		    &cdl_used, &cdl_comp, &cdl_uncomp);
3010 		dsl_deadlist_space(&origin_head->ds_deadlist,
3011 		    &odl_used, &odl_comp, &odl_uncomp);
3012 
3013 		dused = dsl_dataset_phys(clone)->ds_referenced_bytes +
3014 		    cdl_used -
3015 		    (dsl_dataset_phys(origin_head)->ds_referenced_bytes +
3016 		    odl_used);
3017 		dcomp = dsl_dataset_phys(clone)->ds_compressed_bytes +
3018 		    cdl_comp -
3019 		    (dsl_dataset_phys(origin_head)->ds_compressed_bytes +
3020 		    odl_comp);
3021 		duncomp = dsl_dataset_phys(clone)->ds_uncompressed_bytes +
3022 		    cdl_uncomp -
3023 		    (dsl_dataset_phys(origin_head)->ds_uncompressed_bytes +
3024 		    odl_uncomp);
3025 
3026 		dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_HEAD,
3027 		    dused, dcomp, duncomp, tx);
3028 		dsl_dir_diduse_space(clone->ds_dir, DD_USED_HEAD,
3029 		    -dused, -dcomp, -duncomp, tx);
3030 
3031 		/*
3032 		 * The difference in the space used by snapshots is the
3033 		 * difference in snapshot space due to the head's
3034 		 * deadlist (since that's the only thing that's
3035 		 * changing that affects the snapused).
3036 		 */
3037 		dsl_deadlist_space_range(&clone->ds_deadlist,
3038 		    origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
3039 		    &cdl_used, &cdl_comp, &cdl_uncomp);
3040 		dsl_deadlist_space_range(&origin_head->ds_deadlist,
3041 		    origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
3042 		    &odl_used, &odl_comp, &odl_uncomp);
3043 		dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
3044 		    DD_USED_HEAD, DD_USED_SNAP, tx);
3045 	}
3046 
3047 	/* swap ds_*_bytes */
3048 	SWITCH64(dsl_dataset_phys(origin_head)->ds_referenced_bytes,
3049 	    dsl_dataset_phys(clone)->ds_referenced_bytes);
3050 	SWITCH64(dsl_dataset_phys(origin_head)->ds_compressed_bytes,
3051 	    dsl_dataset_phys(clone)->ds_compressed_bytes);
3052 	SWITCH64(dsl_dataset_phys(origin_head)->ds_uncompressed_bytes,
3053 	    dsl_dataset_phys(clone)->ds_uncompressed_bytes);
3054 	SWITCH64(dsl_dataset_phys(origin_head)->ds_unique_bytes,
3055 	    dsl_dataset_phys(clone)->ds_unique_bytes);
3056 
3057 	/* apply any parent delta for change in unconsumed refreservation */
3058 	dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_REFRSRV,
3059 	    unused_refres_delta, 0, 0, tx);
3060 
3061 	/*
3062 	 * Swap deadlists.
3063 	 */
3064 	dsl_deadlist_close(&clone->ds_deadlist);
3065 	dsl_deadlist_close(&origin_head->ds_deadlist);
3066 	SWITCH64(dsl_dataset_phys(origin_head)->ds_deadlist_obj,
3067 	    dsl_dataset_phys(clone)->ds_deadlist_obj);
3068 	dsl_deadlist_open(&clone->ds_deadlist, dp->dp_meta_objset,
3069 	    dsl_dataset_phys(clone)->ds_deadlist_obj);
3070 	dsl_deadlist_open(&origin_head->ds_deadlist, dp->dp_meta_objset,
3071 	    dsl_dataset_phys(origin_head)->ds_deadlist_obj);
3072 
3073 	dsl_scan_ds_clone_swapped(origin_head, clone, tx);
3074 
3075 	spa_history_log_internal_ds(clone, "clone swap", tx,
3076 	    "parent=%s", origin_head->ds_dir->dd_myname);
3077 }
3078 
3079 /*
3080  * Given a pool name and a dataset object number in that pool,
3081  * return the name of that dataset.
3082  */
3083 int
3084 dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf)
3085 {
3086 	dsl_pool_t *dp;
3087 	dsl_dataset_t *ds;
3088 	int error;
3089 
3090 	error = dsl_pool_hold(pname, FTAG, &dp);
3091 	if (error != 0)
3092 		return (error);
3093 
3094 	error = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
3095 	if (error == 0) {
3096 		dsl_dataset_name(ds, buf);
3097 		dsl_dataset_rele(ds, FTAG);
3098 	}
3099 	dsl_pool_rele(dp, FTAG);
3100 
3101 	return (error);
3102 }
3103 
3104 int
3105 dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota,
3106     uint64_t asize, uint64_t inflight, uint64_t *used, uint64_t *ref_rsrv)
3107 {
3108 	int error = 0;
3109 
3110 	ASSERT3S(asize, >, 0);
3111 
3112 	/*
3113 	 * *ref_rsrv is the portion of asize that will come from any
3114 	 * unconsumed refreservation space.
3115 	 */
3116 	*ref_rsrv = 0;
3117 
3118 	mutex_enter(&ds->ds_lock);
3119 	/*
3120 	 * Make a space adjustment for reserved bytes.
3121 	 */
3122 	if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes) {
3123 		ASSERT3U(*used, >=,
3124 		    ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
3125 		*used -=
3126 		    (ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
3127 		*ref_rsrv =
3128 		    asize - MIN(asize, parent_delta(ds, asize + inflight));
3129 	}
3130 
3131 	if (!check_quota || ds->ds_quota == 0) {
3132 		mutex_exit(&ds->ds_lock);
3133 		return (0);
3134 	}
3135 	/*
3136 	 * If they are requesting more space, and our current estimate
3137 	 * is over quota, they get to try again unless the actual
3138 	 * on-disk is over quota and there are no pending changes (which
3139 	 * may free up space for us).
3140 	 */
3141 	if (dsl_dataset_phys(ds)->ds_referenced_bytes + inflight >=
3142 	    ds->ds_quota) {
3143 		if (inflight > 0 ||
3144 		    dsl_dataset_phys(ds)->ds_referenced_bytes < ds->ds_quota)
3145 			error = SET_ERROR(ERESTART);
3146 		else
3147 			error = SET_ERROR(EDQUOT);
3148 	}
3149 	mutex_exit(&ds->ds_lock);
3150 
3151 	return (error);
3152 }
3153 
3154 typedef struct dsl_dataset_set_qr_arg {
3155 	const char *ddsqra_name;
3156 	zprop_source_t ddsqra_source;
3157 	uint64_t ddsqra_value;
3158 } dsl_dataset_set_qr_arg_t;
3159 
3160 
3161 /* ARGSUSED */
3162 static int
3163 dsl_dataset_set_refquota_check(void *arg, dmu_tx_t *tx)
3164 {
3165 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3166 	dsl_pool_t *dp = dmu_tx_pool(tx);
3167 	dsl_dataset_t *ds;
3168 	int error;
3169 	uint64_t newval;
3170 
3171 	if (spa_version(dp->dp_spa) < SPA_VERSION_REFQUOTA)
3172 		return (SET_ERROR(ENOTSUP));
3173 
3174 	error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
3175 	if (error != 0)
3176 		return (error);
3177 
3178 	if (ds->ds_is_snapshot) {
3179 		dsl_dataset_rele(ds, FTAG);
3180 		return (SET_ERROR(EINVAL));
3181 	}
3182 
3183 	error = dsl_prop_predict(ds->ds_dir,
3184 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
3185 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
3186 	if (error != 0) {
3187 		dsl_dataset_rele(ds, FTAG);
3188 		return (error);
3189 	}
3190 
3191 	if (newval == 0) {
3192 		dsl_dataset_rele(ds, FTAG);
3193 		return (0);
3194 	}
3195 
3196 	if (newval < dsl_dataset_phys(ds)->ds_referenced_bytes ||
3197 	    newval < ds->ds_reserved) {
3198 		dsl_dataset_rele(ds, FTAG);
3199 		return (SET_ERROR(ENOSPC));
3200 	}
3201 
3202 	dsl_dataset_rele(ds, FTAG);
3203 	return (0);
3204 }
3205 
3206 static void
3207 dsl_dataset_set_refquota_sync(void *arg, dmu_tx_t *tx)
3208 {
3209 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3210 	dsl_pool_t *dp = dmu_tx_pool(tx);
3211 	dsl_dataset_t *ds;
3212 	uint64_t newval;
3213 
3214 	VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
3215 
3216 	dsl_prop_set_sync_impl(ds,
3217 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
3218 	    ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
3219 	    &ddsqra->ddsqra_value, tx);
3220 
3221 	VERIFY0(dsl_prop_get_int_ds(ds,
3222 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA), &newval));
3223 
3224 	if (ds->ds_quota != newval) {
3225 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
3226 		ds->ds_quota = newval;
3227 	}
3228 	dsl_dataset_rele(ds, FTAG);
3229 }
3230 
3231 int
3232 dsl_dataset_set_refquota(const char *dsname, zprop_source_t source,
3233     uint64_t refquota)
3234 {
3235 	dsl_dataset_set_qr_arg_t ddsqra;
3236 
3237 	ddsqra.ddsqra_name = dsname;
3238 	ddsqra.ddsqra_source = source;
3239 	ddsqra.ddsqra_value = refquota;
3240 
3241 	return (dsl_sync_task(dsname, dsl_dataset_set_refquota_check,
3242 	    dsl_dataset_set_refquota_sync, &ddsqra, 0, ZFS_SPACE_CHECK_NONE));
3243 }
3244 
3245 static int
3246 dsl_dataset_set_refreservation_check(void *arg, dmu_tx_t *tx)
3247 {
3248 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3249 	dsl_pool_t *dp = dmu_tx_pool(tx);
3250 	dsl_dataset_t *ds;
3251 	int error;
3252 	uint64_t newval, unique;
3253 
3254 	if (spa_version(dp->dp_spa) < SPA_VERSION_REFRESERVATION)
3255 		return (SET_ERROR(ENOTSUP));
3256 
3257 	error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
3258 	if (error != 0)
3259 		return (error);
3260 
3261 	if (ds->ds_is_snapshot) {
3262 		dsl_dataset_rele(ds, FTAG);
3263 		return (SET_ERROR(EINVAL));
3264 	}
3265 
3266 	error = dsl_prop_predict(ds->ds_dir,
3267 	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
3268 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
3269 	if (error != 0) {
3270 		dsl_dataset_rele(ds, FTAG);
3271 		return (error);
3272 	}
3273 
3274 	/*
3275 	 * If we are doing the preliminary check in open context, the
3276 	 * space estimates may be inaccurate.
3277 	 */
3278 	if (!dmu_tx_is_syncing(tx)) {
3279 		dsl_dataset_rele(ds, FTAG);
3280 		return (0);
3281 	}
3282 
3283 	mutex_enter(&ds->ds_lock);
3284 	if (!DS_UNIQUE_IS_ACCURATE(ds))
3285 		dsl_dataset_recalc_head_uniq(ds);
3286 	unique = dsl_dataset_phys(ds)->ds_unique_bytes;
3287 	mutex_exit(&ds->ds_lock);
3288 
3289 	if (MAX(unique, newval) > MAX(unique, ds->ds_reserved)) {
3290 		uint64_t delta = MAX(unique, newval) -
3291 		    MAX(unique, ds->ds_reserved);
3292 
3293 		if (delta >
3294 		    dsl_dir_space_available(ds->ds_dir, NULL, 0, B_TRUE) ||
3295 		    (ds->ds_quota > 0 && newval > ds->ds_quota)) {
3296 			dsl_dataset_rele(ds, FTAG);
3297 			return (SET_ERROR(ENOSPC));
3298 		}
3299 	}
3300 
3301 	dsl_dataset_rele(ds, FTAG);
3302 	return (0);
3303 }
3304 
3305 void
3306 dsl_dataset_set_refreservation_sync_impl(dsl_dataset_t *ds,
3307     zprop_source_t source, uint64_t value, dmu_tx_t *tx)
3308 {
3309 	uint64_t newval;
3310 	uint64_t unique;
3311 	int64_t delta;
3312 
3313 	dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
3314 	    source, sizeof (value), 1, &value, tx);
3315 
3316 	VERIFY0(dsl_prop_get_int_ds(ds,
3317 	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &newval));
3318 
3319 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
3320 	mutex_enter(&ds->ds_dir->dd_lock);
3321 	mutex_enter(&ds->ds_lock);
3322 	ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
3323 	unique = dsl_dataset_phys(ds)->ds_unique_bytes;
3324 	delta = MAX(0, (int64_t)(newval - unique)) -
3325 	    MAX(0, (int64_t)(ds->ds_reserved - unique));
3326 	ds->ds_reserved = newval;
3327 	mutex_exit(&ds->ds_lock);
3328 
3329 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx);
3330 	mutex_exit(&ds->ds_dir->dd_lock);
3331 }
3332 
3333 static void
3334 dsl_dataset_set_refreservation_sync(void *arg, dmu_tx_t *tx)
3335 {
3336 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3337 	dsl_pool_t *dp = dmu_tx_pool(tx);
3338 	dsl_dataset_t *ds;
3339 
3340 	VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
3341 	dsl_dataset_set_refreservation_sync_impl(ds,
3342 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, tx);
3343 	dsl_dataset_rele(ds, FTAG);
3344 }
3345 
3346 int
3347 dsl_dataset_set_refreservation(const char *dsname, zprop_source_t source,
3348     uint64_t refreservation)
3349 {
3350 	dsl_dataset_set_qr_arg_t ddsqra;
3351 
3352 	ddsqra.ddsqra_name = dsname;
3353 	ddsqra.ddsqra_source = source;
3354 	ddsqra.ddsqra_value = refreservation;
3355 
3356 	return (dsl_sync_task(dsname, dsl_dataset_set_refreservation_check,
3357 	    dsl_dataset_set_refreservation_sync, &ddsqra,
3358 	    0, ZFS_SPACE_CHECK_NONE));
3359 }
3360 
3361 /*
3362  * Return (in *usedp) the amount of space written in new that is not
3363  * present in oldsnap.  New may be a snapshot or the head.  Old must be
3364  * a snapshot before new, in new's filesystem (or its origin).  If not then
3365  * fail and return EINVAL.
3366  *
3367  * The written space is calculated by considering two components:  First, we
3368  * ignore any freed space, and calculate the written as new's used space
3369  * minus old's used space.  Next, we add in the amount of space that was freed
3370  * between the two snapshots, thus reducing new's used space relative to old's.
3371  * Specifically, this is the space that was born before old->ds_creation_txg,
3372  * and freed before new (ie. on new's deadlist or a previous deadlist).
3373  *
3374  * space freed                         [---------------------]
3375  * snapshots                       ---O-------O--------O-------O------
3376  *                                         oldsnap            new
3377  */
3378 int
3379 dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
3380     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
3381 {
3382 	int err = 0;
3383 	uint64_t snapobj;
3384 	dsl_pool_t *dp = new->ds_dir->dd_pool;
3385 
3386 	ASSERT(dsl_pool_config_held(dp));
3387 
3388 	*usedp = 0;
3389 	*usedp += dsl_dataset_phys(new)->ds_referenced_bytes;
3390 	*usedp -= dsl_dataset_phys(oldsnap)->ds_referenced_bytes;
3391 
3392 	*compp = 0;
3393 	*compp += dsl_dataset_phys(new)->ds_compressed_bytes;
3394 	*compp -= dsl_dataset_phys(oldsnap)->ds_compressed_bytes;
3395 
3396 	*uncompp = 0;
3397 	*uncompp += dsl_dataset_phys(new)->ds_uncompressed_bytes;
3398 	*uncompp -= dsl_dataset_phys(oldsnap)->ds_uncompressed_bytes;
3399 
3400 	snapobj = new->ds_object;
3401 	while (snapobj != oldsnap->ds_object) {
3402 		dsl_dataset_t *snap;
3403 		uint64_t used, comp, uncomp;
3404 
3405 		if (snapobj == new->ds_object) {
3406 			snap = new;
3407 		} else {
3408 			err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
3409 			if (err != 0)
3410 				break;
3411 		}
3412 
3413 		if (dsl_dataset_phys(snap)->ds_prev_snap_txg ==
3414 		    dsl_dataset_phys(oldsnap)->ds_creation_txg) {
3415 			/*
3416 			 * The blocks in the deadlist can not be born after
3417 			 * ds_prev_snap_txg, so get the whole deadlist space,
3418 			 * which is more efficient (especially for old-format
3419 			 * deadlists).  Unfortunately the deadlist code
3420 			 * doesn't have enough information to make this
3421 			 * optimization itself.
3422 			 */
3423 			dsl_deadlist_space(&snap->ds_deadlist,
3424 			    &used, &comp, &uncomp);
3425 		} else {
3426 			dsl_deadlist_space_range(&snap->ds_deadlist,
3427 			    0, dsl_dataset_phys(oldsnap)->ds_creation_txg,
3428 			    &used, &comp, &uncomp);
3429 		}
3430 		*usedp += used;
3431 		*compp += comp;
3432 		*uncompp += uncomp;
3433 
3434 		/*
3435 		 * If we get to the beginning of the chain of snapshots
3436 		 * (ds_prev_snap_obj == 0) before oldsnap, then oldsnap
3437 		 * was not a snapshot of/before new.
3438 		 */
3439 		snapobj = dsl_dataset_phys(snap)->ds_prev_snap_obj;
3440 		if (snap != new)
3441 			dsl_dataset_rele(snap, FTAG);
3442 		if (snapobj == 0) {
3443 			err = SET_ERROR(EINVAL);
3444 			break;
3445 		}
3446 
3447 	}
3448 	return (err);
3449 }
3450 
3451 /*
3452  * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
3453  * lastsnap, and all snapshots in between are deleted.
3454  *
3455  * blocks that would be freed            [---------------------------]
3456  * snapshots                       ---O-------O--------O-------O--------O
3457  *                                        firstsnap        lastsnap
3458  *
3459  * This is the set of blocks that were born after the snap before firstsnap,
3460  * (birth > firstsnap->prev_snap_txg) and died before the snap after the
3461  * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
3462  * We calculate this by iterating over the relevant deadlists (from the snap
3463  * after lastsnap, backward to the snap after firstsnap), summing up the
3464  * space on the deadlist that was born after the snap before firstsnap.
3465  */
3466 int
3467 dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
3468     dsl_dataset_t *lastsnap,
3469     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
3470 {
3471 	int err = 0;
3472 	uint64_t snapobj;
3473 	dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
3474 
3475 	ASSERT(firstsnap->ds_is_snapshot);
3476 	ASSERT(lastsnap->ds_is_snapshot);
3477 
3478 	/*
3479 	 * Check that the snapshots are in the same dsl_dir, and firstsnap
3480 	 * is before lastsnap.
3481 	 */
3482 	if (firstsnap->ds_dir != lastsnap->ds_dir ||
3483 	    dsl_dataset_phys(firstsnap)->ds_creation_txg >
3484 	    dsl_dataset_phys(lastsnap)->ds_creation_txg)
3485 		return (SET_ERROR(EINVAL));
3486 
3487 	*usedp = *compp = *uncompp = 0;
3488 
3489 	snapobj = dsl_dataset_phys(lastsnap)->ds_next_snap_obj;
3490 	while (snapobj != firstsnap->ds_object) {
3491 		dsl_dataset_t *ds;
3492 		uint64_t used, comp, uncomp;
3493 
3494 		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
3495 		if (err != 0)
3496 			break;
3497 
3498 		dsl_deadlist_space_range(&ds->ds_deadlist,
3499 		    dsl_dataset_phys(firstsnap)->ds_prev_snap_txg, UINT64_MAX,
3500 		    &used, &comp, &uncomp);
3501 		*usedp += used;
3502 		*compp += comp;
3503 		*uncompp += uncomp;
3504 
3505 		snapobj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
3506 		ASSERT3U(snapobj, !=, 0);
3507 		dsl_dataset_rele(ds, FTAG);
3508 	}
3509 	return (err);
3510 }
3511 
3512 /*
3513  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
3514  * For example, they could both be snapshots of the same filesystem, and
3515  * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
3516  * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
3517  * filesystem.  Or 'earlier' could be the origin's origin.
3518  *
3519  * If non-zero, earlier_txg is used instead of earlier's ds_creation_txg.
3520  */
3521 boolean_t
3522 dsl_dataset_is_before(dsl_dataset_t *later, dsl_dataset_t *earlier,
3523     uint64_t earlier_txg)
3524 {
3525 	dsl_pool_t *dp = later->ds_dir->dd_pool;
3526 	int error;
3527 	boolean_t ret;
3528 
3529 	ASSERT(dsl_pool_config_held(dp));
3530 	ASSERT(earlier->ds_is_snapshot || earlier_txg != 0);
3531 
3532 	if (earlier_txg == 0)
3533 		earlier_txg = dsl_dataset_phys(earlier)->ds_creation_txg;
3534 
3535 	if (later->ds_is_snapshot &&
3536 	    earlier_txg >= dsl_dataset_phys(later)->ds_creation_txg)
3537 		return (B_FALSE);
3538 
3539 	if (later->ds_dir == earlier->ds_dir)
3540 		return (B_TRUE);
3541 	if (!dsl_dir_is_clone(later->ds_dir))
3542 		return (B_FALSE);
3543 
3544 	if (dsl_dir_phys(later->ds_dir)->dd_origin_obj == earlier->ds_object)
3545 		return (B_TRUE);
3546 	dsl_dataset_t *origin;
3547 	error = dsl_dataset_hold_obj(dp,
3548 	    dsl_dir_phys(later->ds_dir)->dd_origin_obj, FTAG, &origin);
3549 	if (error != 0)
3550 		return (B_FALSE);
3551 	ret = dsl_dataset_is_before(origin, earlier, earlier_txg);
3552 	dsl_dataset_rele(origin, FTAG);
3553 	return (ret);
3554 }
3555 
3556 void
3557 dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx)
3558 {
3559 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
3560 	dmu_object_zapify(mos, ds->ds_object, DMU_OT_DSL_DATASET, tx);
3561 }
3562 
3563 boolean_t
3564 dsl_dataset_is_zapified(dsl_dataset_t *ds)
3565 {
3566 	dmu_object_info_t doi;
3567 
3568 	dmu_object_info_from_db(ds->ds_dbuf, &doi);
3569 	return (doi.doi_type == DMU_OTN_ZAP_METADATA);
3570 }
3571 
3572 boolean_t
3573 dsl_dataset_has_resume_receive_state(dsl_dataset_t *ds)
3574 {
3575 	return (dsl_dataset_is_zapified(ds) &&
3576 	    zap_contains(ds->ds_dir->dd_pool->dp_meta_objset,
3577 	    ds->ds_object, DS_FIELD_RESUME_TOGUID) == 0);
3578 }
3579