xref: /illumos-gate/usr/src/uts/common/fs/zfs/dsl_dataset.c (revision 5f7a8e6d750cb070a3347f045201c6206caee6aa)
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, 2015 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 static void
273 dsl_dataset_evict(void *dbu)
274 {
275 	dsl_dataset_t *ds = dbu;
276 
277 	ASSERT(ds->ds_owner == NULL);
278 
279 	ds->ds_dbuf = NULL;
280 
281 	unique_remove(ds->ds_fsid_guid);
282 
283 	if (ds->ds_objset != NULL)
284 		dmu_objset_evict(ds->ds_objset);
285 
286 	if (ds->ds_prev) {
287 		dsl_dataset_rele(ds->ds_prev, ds);
288 		ds->ds_prev = NULL;
289 	}
290 
291 	bplist_destroy(&ds->ds_pending_deadlist);
292 	if (ds->ds_deadlist.dl_os != NULL)
293 		dsl_deadlist_close(&ds->ds_deadlist);
294 	if (ds->ds_dir)
295 		dsl_dir_async_rele(ds->ds_dir, ds);
296 
297 	ASSERT(!list_link_active(&ds->ds_synced_link));
298 
299 	list_destroy(&ds->ds_prop_cbs);
300 	mutex_destroy(&ds->ds_lock);
301 	mutex_destroy(&ds->ds_opening_lock);
302 	mutex_destroy(&ds->ds_sendstream_lock);
303 	refcount_destroy(&ds->ds_longholds);
304 
305 	kmem_free(ds, sizeof (dsl_dataset_t));
306 }
307 
308 int
309 dsl_dataset_get_snapname(dsl_dataset_t *ds)
310 {
311 	dsl_dataset_phys_t *headphys;
312 	int err;
313 	dmu_buf_t *headdbuf;
314 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
315 	objset_t *mos = dp->dp_meta_objset;
316 
317 	if (ds->ds_snapname[0])
318 		return (0);
319 	if (dsl_dataset_phys(ds)->ds_next_snap_obj == 0)
320 		return (0);
321 
322 	err = dmu_bonus_hold(mos, dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj,
323 	    FTAG, &headdbuf);
324 	if (err != 0)
325 		return (err);
326 	headphys = headdbuf->db_data;
327 	err = zap_value_search(dp->dp_meta_objset,
328 	    headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
329 	dmu_buf_rele(headdbuf, FTAG);
330 	return (err);
331 }
332 
333 int
334 dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value)
335 {
336 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
337 	uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
338 	matchtype_t mt;
339 	int err;
340 
341 	if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
342 		mt = MT_FIRST;
343 	else
344 		mt = MT_EXACT;
345 
346 	err = zap_lookup_norm(mos, snapobj, name, 8, 1,
347 	    value, mt, NULL, 0, NULL);
348 	if (err == ENOTSUP && mt == MT_FIRST)
349 		err = zap_lookup(mos, snapobj, name, 8, 1, value);
350 	return (err);
351 }
352 
353 int
354 dsl_dataset_snap_remove(dsl_dataset_t *ds, const char *name, dmu_tx_t *tx,
355     boolean_t adj_cnt)
356 {
357 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
358 	uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
359 	matchtype_t mt;
360 	int err;
361 
362 	dsl_dir_snap_cmtime_update(ds->ds_dir);
363 
364 	if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
365 		mt = MT_FIRST;
366 	else
367 		mt = MT_EXACT;
368 
369 	err = zap_remove_norm(mos, snapobj, name, mt, tx);
370 	if (err == ENOTSUP && mt == MT_FIRST)
371 		err = zap_remove(mos, snapobj, name, tx);
372 
373 	if (err == 0 && adj_cnt)
374 		dsl_fs_ss_count_adjust(ds->ds_dir, -1,
375 		    DD_FIELD_SNAPSHOT_COUNT, tx);
376 
377 	return (err);
378 }
379 
380 boolean_t
381 dsl_dataset_try_add_ref(dsl_pool_t *dp, dsl_dataset_t *ds, void *tag)
382 {
383 	dmu_buf_t *dbuf = ds->ds_dbuf;
384 	boolean_t result = B_FALSE;
385 
386 	if (dbuf != NULL && dmu_buf_try_add_ref(dbuf, dp->dp_meta_objset,
387 	    ds->ds_object, DMU_BONUS_BLKID, tag)) {
388 
389 		if (ds == dmu_buf_get_user(dbuf))
390 			result = B_TRUE;
391 		else
392 			dmu_buf_rele(dbuf, tag);
393 	}
394 
395 	return (result);
396 }
397 
398 int
399 dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, void *tag,
400     dsl_dataset_t **dsp)
401 {
402 	objset_t *mos = dp->dp_meta_objset;
403 	dmu_buf_t *dbuf;
404 	dsl_dataset_t *ds;
405 	int err;
406 	dmu_object_info_t doi;
407 
408 	ASSERT(dsl_pool_config_held(dp));
409 
410 	err = dmu_bonus_hold(mos, dsobj, tag, &dbuf);
411 	if (err != 0)
412 		return (err);
413 
414 	/* Make sure dsobj has the correct object type. */
415 	dmu_object_info_from_db(dbuf, &doi);
416 	if (doi.doi_bonus_type != DMU_OT_DSL_DATASET) {
417 		dmu_buf_rele(dbuf, tag);
418 		return (SET_ERROR(EINVAL));
419 	}
420 
421 	ds = dmu_buf_get_user(dbuf);
422 	if (ds == NULL) {
423 		dsl_dataset_t *winner = NULL;
424 
425 		ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP);
426 		ds->ds_dbuf = dbuf;
427 		ds->ds_object = dsobj;
428 		ds->ds_is_snapshot = dsl_dataset_phys(ds)->ds_num_children != 0;
429 
430 		mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
431 		mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
432 		mutex_init(&ds->ds_sendstream_lock, NULL, MUTEX_DEFAULT, NULL);
433 		refcount_create(&ds->ds_longholds);
434 
435 		bplist_create(&ds->ds_pending_deadlist);
436 		dsl_deadlist_open(&ds->ds_deadlist,
437 		    mos, dsl_dataset_phys(ds)->ds_deadlist_obj);
438 
439 		list_create(&ds->ds_sendstreams, sizeof (dmu_sendarg_t),
440 		    offsetof(dmu_sendarg_t, dsa_link));
441 
442 		list_create(&ds->ds_prop_cbs, sizeof (dsl_prop_cb_record_t),
443 		    offsetof(dsl_prop_cb_record_t, cbr_ds_node));
444 
445 		if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
446 			for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
447 				if (!(spa_feature_table[f].fi_flags &
448 				    ZFEATURE_FLAG_PER_DATASET))
449 					continue;
450 				err = zap_contains(mos, dsobj,
451 				    spa_feature_table[f].fi_guid);
452 				if (err == 0) {
453 					ds->ds_feature_inuse[f] = B_TRUE;
454 				} else {
455 					ASSERT3U(err, ==, ENOENT);
456 					err = 0;
457 				}
458 			}
459 		}
460 
461 		err = dsl_dir_hold_obj(dp,
462 		    dsl_dataset_phys(ds)->ds_dir_obj, NULL, ds, &ds->ds_dir);
463 		if (err != 0) {
464 			mutex_destroy(&ds->ds_lock);
465 			mutex_destroy(&ds->ds_opening_lock);
466 			mutex_destroy(&ds->ds_sendstream_lock);
467 			refcount_destroy(&ds->ds_longholds);
468 			bplist_destroy(&ds->ds_pending_deadlist);
469 			dsl_deadlist_close(&ds->ds_deadlist);
470 			kmem_free(ds, sizeof (dsl_dataset_t));
471 			dmu_buf_rele(dbuf, tag);
472 			return (err);
473 		}
474 
475 		if (!ds->ds_is_snapshot) {
476 			ds->ds_snapname[0] = '\0';
477 			if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
478 				err = dsl_dataset_hold_obj(dp,
479 				    dsl_dataset_phys(ds)->ds_prev_snap_obj,
480 				    ds, &ds->ds_prev);
481 			}
482 			if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
483 				int zaperr = zap_lookup(mos, ds->ds_object,
484 				    DS_FIELD_BOOKMARK_NAMES,
485 				    sizeof (ds->ds_bookmarks), 1,
486 				    &ds->ds_bookmarks);
487 				if (zaperr != ENOENT)
488 					VERIFY0(zaperr);
489 			}
490 		} else {
491 			if (zfs_flags & ZFS_DEBUG_SNAPNAMES)
492 				err = dsl_dataset_get_snapname(ds);
493 			if (err == 0 &&
494 			    dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
495 				err = zap_count(
496 				    ds->ds_dir->dd_pool->dp_meta_objset,
497 				    dsl_dataset_phys(ds)->ds_userrefs_obj,
498 				    &ds->ds_userrefs);
499 			}
500 		}
501 
502 		if (err == 0 && !ds->ds_is_snapshot) {
503 			err = dsl_prop_get_int_ds(ds,
504 			    zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
505 			    &ds->ds_reserved);
506 			if (err == 0) {
507 				err = dsl_prop_get_int_ds(ds,
508 				    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
509 				    &ds->ds_quota);
510 			}
511 		} else {
512 			ds->ds_reserved = ds->ds_quota = 0;
513 		}
514 
515 		dmu_buf_init_user(&ds->ds_dbu, dsl_dataset_evict, &ds->ds_dbuf);
516 		if (err == 0)
517 			winner = dmu_buf_set_user_ie(dbuf, &ds->ds_dbu);
518 
519 		if (err != 0 || winner != NULL) {
520 			bplist_destroy(&ds->ds_pending_deadlist);
521 			dsl_deadlist_close(&ds->ds_deadlist);
522 			if (ds->ds_prev)
523 				dsl_dataset_rele(ds->ds_prev, ds);
524 			dsl_dir_rele(ds->ds_dir, ds);
525 			mutex_destroy(&ds->ds_lock);
526 			mutex_destroy(&ds->ds_opening_lock);
527 			mutex_destroy(&ds->ds_sendstream_lock);
528 			refcount_destroy(&ds->ds_longholds);
529 			kmem_free(ds, sizeof (dsl_dataset_t));
530 			if (err != 0) {
531 				dmu_buf_rele(dbuf, tag);
532 				return (err);
533 			}
534 			ds = winner;
535 		} else {
536 			ds->ds_fsid_guid =
537 			    unique_insert(dsl_dataset_phys(ds)->ds_fsid_guid);
538 		}
539 	}
540 	ASSERT3P(ds->ds_dbuf, ==, dbuf);
541 	ASSERT3P(dsl_dataset_phys(ds), ==, dbuf->db_data);
542 	ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0 ||
543 	    spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
544 	    dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
545 	*dsp = ds;
546 	return (0);
547 }
548 
549 int
550 dsl_dataset_hold(dsl_pool_t *dp, const char *name,
551     void *tag, dsl_dataset_t **dsp)
552 {
553 	dsl_dir_t *dd;
554 	const char *snapname;
555 	uint64_t obj;
556 	int err = 0;
557 	dsl_dataset_t *ds;
558 
559 	err = dsl_dir_hold(dp, name, FTAG, &dd, &snapname);
560 	if (err != 0)
561 		return (err);
562 
563 	ASSERT(dsl_pool_config_held(dp));
564 	obj = dsl_dir_phys(dd)->dd_head_dataset_obj;
565 	if (obj != 0)
566 		err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
567 	else
568 		err = SET_ERROR(ENOENT);
569 
570 	/* we may be looking for a snapshot */
571 	if (err == 0 && snapname != NULL) {
572 		dsl_dataset_t *snap_ds;
573 
574 		if (*snapname++ != '@') {
575 			dsl_dataset_rele(ds, tag);
576 			dsl_dir_rele(dd, FTAG);
577 			return (SET_ERROR(ENOENT));
578 		}
579 
580 		dprintf("looking for snapshot '%s'\n", snapname);
581 		err = dsl_dataset_snap_lookup(ds, snapname, &obj);
582 		if (err == 0)
583 			err = dsl_dataset_hold_obj(dp, obj, tag, &snap_ds);
584 		dsl_dataset_rele(ds, tag);
585 
586 		if (err == 0) {
587 			mutex_enter(&snap_ds->ds_lock);
588 			if (snap_ds->ds_snapname[0] == 0)
589 				(void) strlcpy(snap_ds->ds_snapname, snapname,
590 				    sizeof (snap_ds->ds_snapname));
591 			mutex_exit(&snap_ds->ds_lock);
592 			ds = snap_ds;
593 		}
594 	}
595 	if (err == 0)
596 		*dsp = ds;
597 	dsl_dir_rele(dd, FTAG);
598 	return (err);
599 }
600 
601 int
602 dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj,
603     void *tag, dsl_dataset_t **dsp)
604 {
605 	int err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp);
606 	if (err != 0)
607 		return (err);
608 	if (!dsl_dataset_tryown(*dsp, tag)) {
609 		dsl_dataset_rele(*dsp, tag);
610 		*dsp = NULL;
611 		return (SET_ERROR(EBUSY));
612 	}
613 	return (0);
614 }
615 
616 int
617 dsl_dataset_own(dsl_pool_t *dp, const char *name,
618     void *tag, dsl_dataset_t **dsp)
619 {
620 	int err = dsl_dataset_hold(dp, name, tag, dsp);
621 	if (err != 0)
622 		return (err);
623 	if (!dsl_dataset_tryown(*dsp, tag)) {
624 		dsl_dataset_rele(*dsp, tag);
625 		return (SET_ERROR(EBUSY));
626 	}
627 	return (0);
628 }
629 
630 /*
631  * See the comment above dsl_pool_hold() for details.  In summary, a long
632  * hold is used to prevent destruction of a dataset while the pool hold
633  * is dropped, allowing other concurrent operations (e.g. spa_sync()).
634  *
635  * The dataset and pool must be held when this function is called.  After it
636  * is called, the pool hold may be released while the dataset is still held
637  * and accessed.
638  */
639 void
640 dsl_dataset_long_hold(dsl_dataset_t *ds, void *tag)
641 {
642 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
643 	(void) refcount_add(&ds->ds_longholds, tag);
644 }
645 
646 void
647 dsl_dataset_long_rele(dsl_dataset_t *ds, void *tag)
648 {
649 	(void) refcount_remove(&ds->ds_longholds, tag);
650 }
651 
652 /* Return B_TRUE if there are any long holds on this dataset. */
653 boolean_t
654 dsl_dataset_long_held(dsl_dataset_t *ds)
655 {
656 	return (!refcount_is_zero(&ds->ds_longholds));
657 }
658 
659 void
660 dsl_dataset_name(dsl_dataset_t *ds, char *name)
661 {
662 	if (ds == NULL) {
663 		(void) strcpy(name, "mos");
664 	} else {
665 		dsl_dir_name(ds->ds_dir, name);
666 		VERIFY0(dsl_dataset_get_snapname(ds));
667 		if (ds->ds_snapname[0]) {
668 			(void) strcat(name, "@");
669 			/*
670 			 * We use a "recursive" mutex so that we
671 			 * can call dprintf_ds() with ds_lock held.
672 			 */
673 			if (!MUTEX_HELD(&ds->ds_lock)) {
674 				mutex_enter(&ds->ds_lock);
675 				(void) strcat(name, ds->ds_snapname);
676 				mutex_exit(&ds->ds_lock);
677 			} else {
678 				(void) strcat(name, ds->ds_snapname);
679 			}
680 		}
681 	}
682 }
683 
684 void
685 dsl_dataset_rele(dsl_dataset_t *ds, void *tag)
686 {
687 	dmu_buf_rele(ds->ds_dbuf, tag);
688 }
689 
690 void
691 dsl_dataset_disown(dsl_dataset_t *ds, void *tag)
692 {
693 	ASSERT3P(ds->ds_owner, ==, tag);
694 	ASSERT(ds->ds_dbuf != NULL);
695 
696 	mutex_enter(&ds->ds_lock);
697 	ds->ds_owner = NULL;
698 	mutex_exit(&ds->ds_lock);
699 	dsl_dataset_long_rele(ds, tag);
700 	dsl_dataset_rele(ds, tag);
701 }
702 
703 boolean_t
704 dsl_dataset_tryown(dsl_dataset_t *ds, void *tag)
705 {
706 	boolean_t gotit = FALSE;
707 
708 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
709 	mutex_enter(&ds->ds_lock);
710 	if (ds->ds_owner == NULL && !DS_IS_INCONSISTENT(ds)) {
711 		ds->ds_owner = tag;
712 		dsl_dataset_long_hold(ds, tag);
713 		gotit = TRUE;
714 	}
715 	mutex_exit(&ds->ds_lock);
716 	return (gotit);
717 }
718 
719 boolean_t
720 dsl_dataset_has_owner(dsl_dataset_t *ds)
721 {
722 	boolean_t rv;
723 	mutex_enter(&ds->ds_lock);
724 	rv = (ds->ds_owner != NULL);
725 	mutex_exit(&ds->ds_lock);
726 	return (rv);
727 }
728 
729 static void
730 dsl_dataset_activate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
731 {
732 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
733 	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
734 	uint64_t zero = 0;
735 
736 	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
737 
738 	spa_feature_incr(spa, f, tx);
739 	dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
740 
741 	VERIFY0(zap_add(mos, dsobj, spa_feature_table[f].fi_guid,
742 	    sizeof (zero), 1, &zero, tx));
743 }
744 
745 void
746 dsl_dataset_deactivate_feature(uint64_t dsobj, spa_feature_t f, dmu_tx_t *tx)
747 {
748 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
749 	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
750 
751 	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
752 
753 	VERIFY0(zap_remove(mos, dsobj, spa_feature_table[f].fi_guid, tx));
754 	spa_feature_decr(spa, f, tx);
755 }
756 
757 uint64_t
758 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
759     uint64_t flags, dmu_tx_t *tx)
760 {
761 	dsl_pool_t *dp = dd->dd_pool;
762 	dmu_buf_t *dbuf;
763 	dsl_dataset_phys_t *dsphys;
764 	uint64_t dsobj;
765 	objset_t *mos = dp->dp_meta_objset;
766 
767 	if (origin == NULL)
768 		origin = dp->dp_origin_snap;
769 
770 	ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
771 	ASSERT(origin == NULL || dsl_dataset_phys(origin)->ds_num_children > 0);
772 	ASSERT(dmu_tx_is_syncing(tx));
773 	ASSERT(dsl_dir_phys(dd)->dd_head_dataset_obj == 0);
774 
775 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
776 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
777 	VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
778 	dmu_buf_will_dirty(dbuf, tx);
779 	dsphys = dbuf->db_data;
780 	bzero(dsphys, sizeof (dsl_dataset_phys_t));
781 	dsphys->ds_dir_obj = dd->dd_object;
782 	dsphys->ds_flags = flags;
783 	dsphys->ds_fsid_guid = unique_create();
784 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
785 	    sizeof (dsphys->ds_guid));
786 	dsphys->ds_snapnames_zapobj =
787 	    zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP,
788 	    DMU_OT_NONE, 0, tx);
789 	dsphys->ds_creation_time = gethrestime_sec();
790 	dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg;
791 
792 	if (origin == NULL) {
793 		dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx);
794 	} else {
795 		dsl_dataset_t *ohds; /* head of the origin snapshot */
796 
797 		dsphys->ds_prev_snap_obj = origin->ds_object;
798 		dsphys->ds_prev_snap_txg =
799 		    dsl_dataset_phys(origin)->ds_creation_txg;
800 		dsphys->ds_referenced_bytes =
801 		    dsl_dataset_phys(origin)->ds_referenced_bytes;
802 		dsphys->ds_compressed_bytes =
803 		    dsl_dataset_phys(origin)->ds_compressed_bytes;
804 		dsphys->ds_uncompressed_bytes =
805 		    dsl_dataset_phys(origin)->ds_uncompressed_bytes;
806 		dsphys->ds_bp = dsl_dataset_phys(origin)->ds_bp;
807 
808 		/*
809 		 * Inherit flags that describe the dataset's contents
810 		 * (INCONSISTENT) or properties (Case Insensitive).
811 		 */
812 		dsphys->ds_flags |= dsl_dataset_phys(origin)->ds_flags &
813 		    (DS_FLAG_INCONSISTENT | DS_FLAG_CI_DATASET);
814 
815 		for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
816 			if (origin->ds_feature_inuse[f])
817 				dsl_dataset_activate_feature(dsobj, f, tx);
818 		}
819 
820 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
821 		dsl_dataset_phys(origin)->ds_num_children++;
822 
823 		VERIFY0(dsl_dataset_hold_obj(dp,
824 		    dsl_dir_phys(origin->ds_dir)->dd_head_dataset_obj,
825 		    FTAG, &ohds));
826 		dsphys->ds_deadlist_obj = dsl_deadlist_clone(&ohds->ds_deadlist,
827 		    dsphys->ds_prev_snap_txg, dsphys->ds_prev_snap_obj, tx);
828 		dsl_dataset_rele(ohds, FTAG);
829 
830 		if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) {
831 			if (dsl_dataset_phys(origin)->ds_next_clones_obj == 0) {
832 				dsl_dataset_phys(origin)->ds_next_clones_obj =
833 				    zap_create(mos,
834 				    DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
835 			}
836 			VERIFY0(zap_add_int(mos,
837 			    dsl_dataset_phys(origin)->ds_next_clones_obj,
838 			    dsobj, tx));
839 		}
840 
841 		dmu_buf_will_dirty(dd->dd_dbuf, tx);
842 		dsl_dir_phys(dd)->dd_origin_obj = origin->ds_object;
843 		if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
844 			if (dsl_dir_phys(origin->ds_dir)->dd_clones == 0) {
845 				dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
846 				dsl_dir_phys(origin->ds_dir)->dd_clones =
847 				    zap_create(mos,
848 				    DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
849 			}
850 			VERIFY0(zap_add_int(mos,
851 			    dsl_dir_phys(origin->ds_dir)->dd_clones,
852 			    dsobj, tx));
853 		}
854 	}
855 
856 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
857 		dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
858 
859 	dmu_buf_rele(dbuf, FTAG);
860 
861 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
862 	dsl_dir_phys(dd)->dd_head_dataset_obj = dsobj;
863 
864 	return (dsobj);
865 }
866 
867 static void
868 dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
869 {
870 	objset_t *os;
871 
872 	VERIFY0(dmu_objset_from_ds(ds, &os));
873 	bzero(&os->os_zil_header, sizeof (os->os_zil_header));
874 	dsl_dataset_dirty(ds, tx);
875 }
876 
877 uint64_t
878 dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
879     dsl_dataset_t *origin, uint64_t flags, cred_t *cr, dmu_tx_t *tx)
880 {
881 	dsl_pool_t *dp = pdd->dd_pool;
882 	uint64_t dsobj, ddobj;
883 	dsl_dir_t *dd;
884 
885 	ASSERT(dmu_tx_is_syncing(tx));
886 	ASSERT(lastname[0] != '@');
887 
888 	ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
889 	VERIFY0(dsl_dir_hold_obj(dp, ddobj, lastname, FTAG, &dd));
890 
891 	dsobj = dsl_dataset_create_sync_dd(dd, origin,
892 	    flags & ~DS_CREATE_FLAG_NODIRTY, tx);
893 
894 	dsl_deleg_set_create_perms(dd, tx, cr);
895 
896 	/*
897 	 * Since we're creating a new node we know it's a leaf, so we can
898 	 * initialize the counts if the limit feature is active.
899 	 */
900 	if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT)) {
901 		uint64_t cnt = 0;
902 		objset_t *os = dd->dd_pool->dp_meta_objset;
903 
904 		dsl_dir_zapify(dd, tx);
905 		VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_FILESYSTEM_COUNT,
906 		    sizeof (cnt), 1, &cnt, tx));
907 		VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_SNAPSHOT_COUNT,
908 		    sizeof (cnt), 1, &cnt, tx));
909 	}
910 
911 	dsl_dir_rele(dd, FTAG);
912 
913 	/*
914 	 * If we are creating a clone, make sure we zero out any stale
915 	 * data from the origin snapshots zil header.
916 	 */
917 	if (origin != NULL && !(flags & DS_CREATE_FLAG_NODIRTY)) {
918 		dsl_dataset_t *ds;
919 
920 		VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
921 		dsl_dataset_zero_zil(ds, tx);
922 		dsl_dataset_rele(ds, FTAG);
923 	}
924 
925 	return (dsobj);
926 }
927 
928 /*
929  * The unique space in the head dataset can be calculated by subtracting
930  * the space used in the most recent snapshot, that is still being used
931  * in this file system, from the space currently in use.  To figure out
932  * the space in the most recent snapshot still in use, we need to take
933  * the total space used in the snapshot and subtract out the space that
934  * has been freed up since the snapshot was taken.
935  */
936 void
937 dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
938 {
939 	uint64_t mrs_used;
940 	uint64_t dlused, dlcomp, dluncomp;
941 
942 	ASSERT(!ds->ds_is_snapshot);
943 
944 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0)
945 		mrs_used = dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes;
946 	else
947 		mrs_used = 0;
948 
949 	dsl_deadlist_space(&ds->ds_deadlist, &dlused, &dlcomp, &dluncomp);
950 
951 	ASSERT3U(dlused, <=, mrs_used);
952 	dsl_dataset_phys(ds)->ds_unique_bytes =
953 	    dsl_dataset_phys(ds)->ds_referenced_bytes - (mrs_used - dlused);
954 
955 	if (spa_version(ds->ds_dir->dd_pool->dp_spa) >=
956 	    SPA_VERSION_UNIQUE_ACCURATE)
957 		dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
958 }
959 
960 void
961 dsl_dataset_remove_from_next_clones(dsl_dataset_t *ds, uint64_t obj,
962     dmu_tx_t *tx)
963 {
964 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
965 	uint64_t count;
966 	int err;
967 
968 	ASSERT(dsl_dataset_phys(ds)->ds_num_children >= 2);
969 	err = zap_remove_int(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
970 	    obj, tx);
971 	/*
972 	 * The err should not be ENOENT, but a bug in a previous version
973 	 * of the code could cause upgrade_clones_cb() to not set
974 	 * ds_next_snap_obj when it should, leading to a missing entry.
975 	 * If we knew that the pool was created after
976 	 * SPA_VERSION_NEXT_CLONES, we could assert that it isn't
977 	 * ENOENT.  However, at least we can check that we don't have
978 	 * too many entries in the next_clones_obj even after failing to
979 	 * remove this one.
980 	 */
981 	if (err != ENOENT)
982 		VERIFY0(err);
983 	ASSERT0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
984 	    &count));
985 	ASSERT3U(count, <=, dsl_dataset_phys(ds)->ds_num_children - 2);
986 }
987 
988 
989 blkptr_t *
990 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
991 {
992 	return (&dsl_dataset_phys(ds)->ds_bp);
993 }
994 
995 void
996 dsl_dataset_set_blkptr(dsl_dataset_t *ds, blkptr_t *bp, dmu_tx_t *tx)
997 {
998 	ASSERT(dmu_tx_is_syncing(tx));
999 	/* If it's the meta-objset, set dp_meta_rootbp */
1000 	if (ds == NULL) {
1001 		tx->tx_pool->dp_meta_rootbp = *bp;
1002 	} else {
1003 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
1004 		dsl_dataset_phys(ds)->ds_bp = *bp;
1005 	}
1006 }
1007 
1008 spa_t *
1009 dsl_dataset_get_spa(dsl_dataset_t *ds)
1010 {
1011 	return (ds->ds_dir->dd_pool->dp_spa);
1012 }
1013 
1014 void
1015 dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
1016 {
1017 	dsl_pool_t *dp;
1018 
1019 	if (ds == NULL) /* this is the meta-objset */
1020 		return;
1021 
1022 	ASSERT(ds->ds_objset != NULL);
1023 
1024 	if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0)
1025 		panic("dirtying snapshot!");
1026 
1027 	dp = ds->ds_dir->dd_pool;
1028 
1029 	if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg)) {
1030 		/* up the hold count until we can be written out */
1031 		dmu_buf_add_ref(ds->ds_dbuf, ds);
1032 	}
1033 }
1034 
1035 boolean_t
1036 dsl_dataset_is_dirty(dsl_dataset_t *ds)
1037 {
1038 	for (int t = 0; t < TXG_SIZE; t++) {
1039 		if (txg_list_member(&ds->ds_dir->dd_pool->dp_dirty_datasets,
1040 		    ds, t))
1041 			return (B_TRUE);
1042 	}
1043 	return (B_FALSE);
1044 }
1045 
1046 static int
1047 dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx)
1048 {
1049 	uint64_t asize;
1050 
1051 	if (!dmu_tx_is_syncing(tx))
1052 		return (0);
1053 
1054 	/*
1055 	 * If there's an fs-only reservation, any blocks that might become
1056 	 * owned by the snapshot dataset must be accommodated by space
1057 	 * outside of the reservation.
1058 	 */
1059 	ASSERT(ds->ds_reserved == 0 || DS_UNIQUE_IS_ACCURATE(ds));
1060 	asize = MIN(dsl_dataset_phys(ds)->ds_unique_bytes, ds->ds_reserved);
1061 	if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE))
1062 		return (SET_ERROR(ENOSPC));
1063 
1064 	/*
1065 	 * Propagate any reserved space for this snapshot to other
1066 	 * snapshot checks in this sync group.
1067 	 */
1068 	if (asize > 0)
1069 		dsl_dir_willuse_space(ds->ds_dir, asize, tx);
1070 
1071 	return (0);
1072 }
1073 
1074 typedef struct dsl_dataset_snapshot_arg {
1075 	nvlist_t *ddsa_snaps;
1076 	nvlist_t *ddsa_props;
1077 	nvlist_t *ddsa_errors;
1078 	cred_t *ddsa_cr;
1079 } dsl_dataset_snapshot_arg_t;
1080 
1081 int
1082 dsl_dataset_snapshot_check_impl(dsl_dataset_t *ds, const char *snapname,
1083     dmu_tx_t *tx, boolean_t recv, uint64_t cnt, cred_t *cr)
1084 {
1085 	int error;
1086 	uint64_t value;
1087 
1088 	ds->ds_trysnap_txg = tx->tx_txg;
1089 
1090 	if (!dmu_tx_is_syncing(tx))
1091 		return (0);
1092 
1093 	/*
1094 	 * We don't allow multiple snapshots of the same txg.  If there
1095 	 * is already one, try again.
1096 	 */
1097 	if (dsl_dataset_phys(ds)->ds_prev_snap_txg >= tx->tx_txg)
1098 		return (SET_ERROR(EAGAIN));
1099 
1100 	/*
1101 	 * Check for conflicting snapshot name.
1102 	 */
1103 	error = dsl_dataset_snap_lookup(ds, snapname, &value);
1104 	if (error == 0)
1105 		return (SET_ERROR(EEXIST));
1106 	if (error != ENOENT)
1107 		return (error);
1108 
1109 	/*
1110 	 * We don't allow taking snapshots of inconsistent datasets, such as
1111 	 * those into which we are currently receiving.  However, if we are
1112 	 * creating this snapshot as part of a receive, this check will be
1113 	 * executed atomically with respect to the completion of the receive
1114 	 * itself but prior to the clearing of DS_FLAG_INCONSISTENT; in this
1115 	 * case we ignore this, knowing it will be fixed up for us shortly in
1116 	 * dmu_recv_end_sync().
1117 	 */
1118 	if (!recv && DS_IS_INCONSISTENT(ds))
1119 		return (SET_ERROR(EBUSY));
1120 
1121 	/*
1122 	 * Skip the check for temporary snapshots or if we have already checked
1123 	 * the counts in dsl_dataset_snapshot_check. This means we really only
1124 	 * check the count here when we're receiving a stream.
1125 	 */
1126 	if (cnt != 0 && cr != NULL) {
1127 		error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1128 		    ZFS_PROP_SNAPSHOT_LIMIT, NULL, cr);
1129 		if (error != 0)
1130 			return (error);
1131 	}
1132 
1133 	error = dsl_dataset_snapshot_reserve_space(ds, tx);
1134 	if (error != 0)
1135 		return (error);
1136 
1137 	return (0);
1138 }
1139 
1140 static int
1141 dsl_dataset_snapshot_check(void *arg, dmu_tx_t *tx)
1142 {
1143 	dsl_dataset_snapshot_arg_t *ddsa = arg;
1144 	dsl_pool_t *dp = dmu_tx_pool(tx);
1145 	nvpair_t *pair;
1146 	int rv = 0;
1147 
1148 	/*
1149 	 * Pre-compute how many total new snapshots will be created for each
1150 	 * level in the tree and below. This is needed for validating the
1151 	 * snapshot limit when either taking a recursive snapshot or when
1152 	 * taking multiple snapshots.
1153 	 *
1154 	 * The problem is that the counts are not actually adjusted when
1155 	 * we are checking, only when we finally sync. For a single snapshot,
1156 	 * this is easy, the count will increase by 1 at each node up the tree,
1157 	 * but its more complicated for the recursive/multiple snapshot case.
1158 	 *
1159 	 * The dsl_fs_ss_limit_check function does recursively check the count
1160 	 * at each level up the tree but since it is validating each snapshot
1161 	 * independently we need to be sure that we are validating the complete
1162 	 * count for the entire set of snapshots. We do this by rolling up the
1163 	 * counts for each component of the name into an nvlist and then
1164 	 * checking each of those cases with the aggregated count.
1165 	 *
1166 	 * This approach properly handles not only the recursive snapshot
1167 	 * case (where we get all of those on the ddsa_snaps list) but also
1168 	 * the sibling case (e.g. snapshot a/b and a/c so that we will also
1169 	 * validate the limit on 'a' using a count of 2).
1170 	 *
1171 	 * We validate the snapshot names in the third loop and only report
1172 	 * name errors once.
1173 	 */
1174 	if (dmu_tx_is_syncing(tx)) {
1175 		nvlist_t *cnt_track = NULL;
1176 		cnt_track = fnvlist_alloc();
1177 
1178 		/* Rollup aggregated counts into the cnt_track list */
1179 		for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1180 		    pair != NULL;
1181 		    pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1182 			char *pdelim;
1183 			uint64_t val;
1184 			char nm[MAXPATHLEN];
1185 
1186 			(void) strlcpy(nm, nvpair_name(pair), sizeof (nm));
1187 			pdelim = strchr(nm, '@');
1188 			if (pdelim == NULL)
1189 				continue;
1190 			*pdelim = '\0';
1191 
1192 			do {
1193 				if (nvlist_lookup_uint64(cnt_track, nm,
1194 				    &val) == 0) {
1195 					/* update existing entry */
1196 					fnvlist_add_uint64(cnt_track, nm,
1197 					    val + 1);
1198 				} else {
1199 					/* add to list */
1200 					fnvlist_add_uint64(cnt_track, nm, 1);
1201 				}
1202 
1203 				pdelim = strrchr(nm, '/');
1204 				if (pdelim != NULL)
1205 					*pdelim = '\0';
1206 			} while (pdelim != NULL);
1207 		}
1208 
1209 		/* Check aggregated counts at each level */
1210 		for (pair = nvlist_next_nvpair(cnt_track, NULL);
1211 		    pair != NULL; pair = nvlist_next_nvpair(cnt_track, pair)) {
1212 			int error = 0;
1213 			char *name;
1214 			uint64_t cnt = 0;
1215 			dsl_dataset_t *ds;
1216 
1217 			name = nvpair_name(pair);
1218 			cnt = fnvpair_value_uint64(pair);
1219 			ASSERT(cnt > 0);
1220 
1221 			error = dsl_dataset_hold(dp, name, FTAG, &ds);
1222 			if (error == 0) {
1223 				error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1224 				    ZFS_PROP_SNAPSHOT_LIMIT, NULL,
1225 				    ddsa->ddsa_cr);
1226 				dsl_dataset_rele(ds, FTAG);
1227 			}
1228 
1229 			if (error != 0) {
1230 				if (ddsa->ddsa_errors != NULL)
1231 					fnvlist_add_int32(ddsa->ddsa_errors,
1232 					    name, error);
1233 				rv = error;
1234 				/* only report one error for this check */
1235 				break;
1236 			}
1237 		}
1238 		nvlist_free(cnt_track);
1239 	}
1240 
1241 	for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1242 	    pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1243 		int error = 0;
1244 		dsl_dataset_t *ds;
1245 		char *name, *atp;
1246 		char dsname[MAXNAMELEN];
1247 
1248 		name = nvpair_name(pair);
1249 		if (strlen(name) >= MAXNAMELEN)
1250 			error = SET_ERROR(ENAMETOOLONG);
1251 		if (error == 0) {
1252 			atp = strchr(name, '@');
1253 			if (atp == NULL)
1254 				error = SET_ERROR(EINVAL);
1255 			if (error == 0)
1256 				(void) strlcpy(dsname, name, atp - name + 1);
1257 		}
1258 		if (error == 0)
1259 			error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
1260 		if (error == 0) {
1261 			/* passing 0/NULL skips dsl_fs_ss_limit_check */
1262 			error = dsl_dataset_snapshot_check_impl(ds,
1263 			    atp + 1, tx, B_FALSE, 0, NULL);
1264 			dsl_dataset_rele(ds, FTAG);
1265 		}
1266 
1267 		if (error != 0) {
1268 			if (ddsa->ddsa_errors != NULL) {
1269 				fnvlist_add_int32(ddsa->ddsa_errors,
1270 				    name, error);
1271 			}
1272 			rv = error;
1273 		}
1274 	}
1275 
1276 	return (rv);
1277 }
1278 
1279 void
1280 dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
1281     dmu_tx_t *tx)
1282 {
1283 	static zil_header_t zero_zil;
1284 
1285 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1286 	dmu_buf_t *dbuf;
1287 	dsl_dataset_phys_t *dsphys;
1288 	uint64_t dsobj, crtxg;
1289 	objset_t *mos = dp->dp_meta_objset;
1290 	objset_t *os;
1291 
1292 	ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
1293 
1294 	/*
1295 	 * If we are on an old pool, the zil must not be active, in which
1296 	 * case it will be zeroed.  Usually zil_suspend() accomplishes this.
1297 	 */
1298 	ASSERT(spa_version(dmu_tx_pool(tx)->dp_spa) >= SPA_VERSION_FAST_SNAP ||
1299 	    dmu_objset_from_ds(ds, &os) != 0 ||
1300 	    bcmp(&os->os_phys->os_zil_header, &zero_zil,
1301 	    sizeof (zero_zil)) == 0);
1302 
1303 	dsl_fs_ss_count_adjust(ds->ds_dir, 1, DD_FIELD_SNAPSHOT_COUNT, tx);
1304 
1305 	/*
1306 	 * The origin's ds_creation_txg has to be < TXG_INITIAL
1307 	 */
1308 	if (strcmp(snapname, ORIGIN_DIR_NAME) == 0)
1309 		crtxg = 1;
1310 	else
1311 		crtxg = tx->tx_txg;
1312 
1313 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1314 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1315 	VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1316 	dmu_buf_will_dirty(dbuf, tx);
1317 	dsphys = dbuf->db_data;
1318 	bzero(dsphys, sizeof (dsl_dataset_phys_t));
1319 	dsphys->ds_dir_obj = ds->ds_dir->dd_object;
1320 	dsphys->ds_fsid_guid = unique_create();
1321 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1322 	    sizeof (dsphys->ds_guid));
1323 	dsphys->ds_prev_snap_obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
1324 	dsphys->ds_prev_snap_txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
1325 	dsphys->ds_next_snap_obj = ds->ds_object;
1326 	dsphys->ds_num_children = 1;
1327 	dsphys->ds_creation_time = gethrestime_sec();
1328 	dsphys->ds_creation_txg = crtxg;
1329 	dsphys->ds_deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
1330 	dsphys->ds_referenced_bytes = dsl_dataset_phys(ds)->ds_referenced_bytes;
1331 	dsphys->ds_compressed_bytes = dsl_dataset_phys(ds)->ds_compressed_bytes;
1332 	dsphys->ds_uncompressed_bytes =
1333 	    dsl_dataset_phys(ds)->ds_uncompressed_bytes;
1334 	dsphys->ds_flags = dsl_dataset_phys(ds)->ds_flags;
1335 	dsphys->ds_bp = dsl_dataset_phys(ds)->ds_bp;
1336 	dmu_buf_rele(dbuf, FTAG);
1337 
1338 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1339 		if (ds->ds_feature_inuse[f])
1340 			dsl_dataset_activate_feature(dsobj, f, tx);
1341 	}
1342 
1343 	ASSERT3U(ds->ds_prev != 0, ==,
1344 	    dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
1345 	if (ds->ds_prev) {
1346 		uint64_t next_clones_obj =
1347 		    dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj;
1348 		ASSERT(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1349 		    ds->ds_object ||
1350 		    dsl_dataset_phys(ds->ds_prev)->ds_num_children > 1);
1351 		if (dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1352 		    ds->ds_object) {
1353 			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1354 			ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
1355 			    dsl_dataset_phys(ds->ds_prev)->ds_creation_txg);
1356 			dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj = dsobj;
1357 		} else if (next_clones_obj != 0) {
1358 			dsl_dataset_remove_from_next_clones(ds->ds_prev,
1359 			    dsphys->ds_next_snap_obj, tx);
1360 			VERIFY0(zap_add_int(mos,
1361 			    next_clones_obj, dsobj, tx));
1362 		}
1363 	}
1364 
1365 	/*
1366 	 * If we have a reference-reservation on this dataset, we will
1367 	 * need to increase the amount of refreservation being charged
1368 	 * since our unique space is going to zero.
1369 	 */
1370 	if (ds->ds_reserved) {
1371 		int64_t delta;
1372 		ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
1373 		delta = MIN(dsl_dataset_phys(ds)->ds_unique_bytes,
1374 		    ds->ds_reserved);
1375 		dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV,
1376 		    delta, 0, 0, tx);
1377 	}
1378 
1379 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1380 	dsl_dataset_phys(ds)->ds_deadlist_obj =
1381 	    dsl_deadlist_clone(&ds->ds_deadlist, UINT64_MAX,
1382 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, tx);
1383 	dsl_deadlist_close(&ds->ds_deadlist);
1384 	dsl_deadlist_open(&ds->ds_deadlist, mos,
1385 	    dsl_dataset_phys(ds)->ds_deadlist_obj);
1386 	dsl_deadlist_add_key(&ds->ds_deadlist,
1387 	    dsl_dataset_phys(ds)->ds_prev_snap_txg, tx);
1388 
1389 	ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, <, tx->tx_txg);
1390 	dsl_dataset_phys(ds)->ds_prev_snap_obj = dsobj;
1391 	dsl_dataset_phys(ds)->ds_prev_snap_txg = crtxg;
1392 	dsl_dataset_phys(ds)->ds_unique_bytes = 0;
1393 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1394 		dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1395 
1396 	VERIFY0(zap_add(mos, dsl_dataset_phys(ds)->ds_snapnames_zapobj,
1397 	    snapname, 8, 1, &dsobj, tx));
1398 
1399 	if (ds->ds_prev)
1400 		dsl_dataset_rele(ds->ds_prev, ds);
1401 	VERIFY0(dsl_dataset_hold_obj(dp,
1402 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, ds, &ds->ds_prev));
1403 
1404 	dsl_scan_ds_snapshotted(ds, tx);
1405 
1406 	dsl_dir_snap_cmtime_update(ds->ds_dir);
1407 
1408 	spa_history_log_internal_ds(ds->ds_prev, "snapshot", tx, "");
1409 }
1410 
1411 static void
1412 dsl_dataset_snapshot_sync(void *arg, dmu_tx_t *tx)
1413 {
1414 	dsl_dataset_snapshot_arg_t *ddsa = arg;
1415 	dsl_pool_t *dp = dmu_tx_pool(tx);
1416 	nvpair_t *pair;
1417 
1418 	for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1419 	    pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1420 		dsl_dataset_t *ds;
1421 		char *name, *atp;
1422 		char dsname[MAXNAMELEN];
1423 
1424 		name = nvpair_name(pair);
1425 		atp = strchr(name, '@');
1426 		(void) strlcpy(dsname, name, atp - name + 1);
1427 		VERIFY0(dsl_dataset_hold(dp, dsname, FTAG, &ds));
1428 
1429 		dsl_dataset_snapshot_sync_impl(ds, atp + 1, tx);
1430 		if (ddsa->ddsa_props != NULL) {
1431 			dsl_props_set_sync_impl(ds->ds_prev,
1432 			    ZPROP_SRC_LOCAL, ddsa->ddsa_props, tx);
1433 		}
1434 		dsl_dataset_rele(ds, FTAG);
1435 	}
1436 }
1437 
1438 /*
1439  * The snapshots must all be in the same pool.
1440  * All-or-nothing: if there are any failures, nothing will be modified.
1441  */
1442 int
1443 dsl_dataset_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t *errors)
1444 {
1445 	dsl_dataset_snapshot_arg_t ddsa;
1446 	nvpair_t *pair;
1447 	boolean_t needsuspend;
1448 	int error;
1449 	spa_t *spa;
1450 	char *firstname;
1451 	nvlist_t *suspended = NULL;
1452 
1453 	pair = nvlist_next_nvpair(snaps, NULL);
1454 	if (pair == NULL)
1455 		return (0);
1456 	firstname = nvpair_name(pair);
1457 
1458 	error = spa_open(firstname, &spa, FTAG);
1459 	if (error != 0)
1460 		return (error);
1461 	needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1462 	spa_close(spa, FTAG);
1463 
1464 	if (needsuspend) {
1465 		suspended = fnvlist_alloc();
1466 		for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
1467 		    pair = nvlist_next_nvpair(snaps, pair)) {
1468 			char fsname[MAXNAMELEN];
1469 			char *snapname = nvpair_name(pair);
1470 			char *atp;
1471 			void *cookie;
1472 
1473 			atp = strchr(snapname, '@');
1474 			if (atp == NULL) {
1475 				error = SET_ERROR(EINVAL);
1476 				break;
1477 			}
1478 			(void) strlcpy(fsname, snapname, atp - snapname + 1);
1479 
1480 			error = zil_suspend(fsname, &cookie);
1481 			if (error != 0)
1482 				break;
1483 			fnvlist_add_uint64(suspended, fsname,
1484 			    (uintptr_t)cookie);
1485 		}
1486 	}
1487 
1488 	ddsa.ddsa_snaps = snaps;
1489 	ddsa.ddsa_props = props;
1490 	ddsa.ddsa_errors = errors;
1491 	ddsa.ddsa_cr = CRED();
1492 
1493 	if (error == 0) {
1494 		error = dsl_sync_task(firstname, dsl_dataset_snapshot_check,
1495 		    dsl_dataset_snapshot_sync, &ddsa,
1496 		    fnvlist_num_pairs(snaps) * 3, ZFS_SPACE_CHECK_NORMAL);
1497 	}
1498 
1499 	if (suspended != NULL) {
1500 		for (pair = nvlist_next_nvpair(suspended, NULL); pair != NULL;
1501 		    pair = nvlist_next_nvpair(suspended, pair)) {
1502 			zil_resume((void *)(uintptr_t)
1503 			    fnvpair_value_uint64(pair));
1504 		}
1505 		fnvlist_free(suspended);
1506 	}
1507 
1508 	return (error);
1509 }
1510 
1511 typedef struct dsl_dataset_snapshot_tmp_arg {
1512 	const char *ddsta_fsname;
1513 	const char *ddsta_snapname;
1514 	minor_t ddsta_cleanup_minor;
1515 	const char *ddsta_htag;
1516 } dsl_dataset_snapshot_tmp_arg_t;
1517 
1518 static int
1519 dsl_dataset_snapshot_tmp_check(void *arg, dmu_tx_t *tx)
1520 {
1521 	dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1522 	dsl_pool_t *dp = dmu_tx_pool(tx);
1523 	dsl_dataset_t *ds;
1524 	int error;
1525 
1526 	error = dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds);
1527 	if (error != 0)
1528 		return (error);
1529 
1530 	/* NULL cred means no limit check for tmp snapshot */
1531 	error = dsl_dataset_snapshot_check_impl(ds, ddsta->ddsta_snapname,
1532 	    tx, B_FALSE, 0, NULL);
1533 	if (error != 0) {
1534 		dsl_dataset_rele(ds, FTAG);
1535 		return (error);
1536 	}
1537 
1538 	if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS) {
1539 		dsl_dataset_rele(ds, FTAG);
1540 		return (SET_ERROR(ENOTSUP));
1541 	}
1542 	error = dsl_dataset_user_hold_check_one(NULL, ddsta->ddsta_htag,
1543 	    B_TRUE, tx);
1544 	if (error != 0) {
1545 		dsl_dataset_rele(ds, FTAG);
1546 		return (error);
1547 	}
1548 
1549 	dsl_dataset_rele(ds, FTAG);
1550 	return (0);
1551 }
1552 
1553 static void
1554 dsl_dataset_snapshot_tmp_sync(void *arg, dmu_tx_t *tx)
1555 {
1556 	dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1557 	dsl_pool_t *dp = dmu_tx_pool(tx);
1558 	dsl_dataset_t *ds;
1559 
1560 	VERIFY0(dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds));
1561 
1562 	dsl_dataset_snapshot_sync_impl(ds, ddsta->ddsta_snapname, tx);
1563 	dsl_dataset_user_hold_sync_one(ds->ds_prev, ddsta->ddsta_htag,
1564 	    ddsta->ddsta_cleanup_minor, gethrestime_sec(), tx);
1565 	dsl_destroy_snapshot_sync_impl(ds->ds_prev, B_TRUE, tx);
1566 
1567 	dsl_dataset_rele(ds, FTAG);
1568 }
1569 
1570 int
1571 dsl_dataset_snapshot_tmp(const char *fsname, const char *snapname,
1572     minor_t cleanup_minor, const char *htag)
1573 {
1574 	dsl_dataset_snapshot_tmp_arg_t ddsta;
1575 	int error;
1576 	spa_t *spa;
1577 	boolean_t needsuspend;
1578 	void *cookie;
1579 
1580 	ddsta.ddsta_fsname = fsname;
1581 	ddsta.ddsta_snapname = snapname;
1582 	ddsta.ddsta_cleanup_minor = cleanup_minor;
1583 	ddsta.ddsta_htag = htag;
1584 
1585 	error = spa_open(fsname, &spa, FTAG);
1586 	if (error != 0)
1587 		return (error);
1588 	needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1589 	spa_close(spa, FTAG);
1590 
1591 	if (needsuspend) {
1592 		error = zil_suspend(fsname, &cookie);
1593 		if (error != 0)
1594 			return (error);
1595 	}
1596 
1597 	error = dsl_sync_task(fsname, dsl_dataset_snapshot_tmp_check,
1598 	    dsl_dataset_snapshot_tmp_sync, &ddsta, 3, ZFS_SPACE_CHECK_RESERVED);
1599 
1600 	if (needsuspend)
1601 		zil_resume(cookie);
1602 	return (error);
1603 }
1604 
1605 
1606 void
1607 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
1608 {
1609 	ASSERT(dmu_tx_is_syncing(tx));
1610 	ASSERT(ds->ds_objset != NULL);
1611 	ASSERT(dsl_dataset_phys(ds)->ds_next_snap_obj == 0);
1612 
1613 	/*
1614 	 * in case we had to change ds_fsid_guid when we opened it,
1615 	 * sync it out now.
1616 	 */
1617 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1618 	dsl_dataset_phys(ds)->ds_fsid_guid = ds->ds_fsid_guid;
1619 
1620 	if (ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] != 0) {
1621 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1622 		    ds->ds_object, DS_FIELD_RESUME_OBJECT, 8, 1,
1623 		    &ds->ds_resume_object[tx->tx_txg & TXG_MASK], tx));
1624 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1625 		    ds->ds_object, DS_FIELD_RESUME_OFFSET, 8, 1,
1626 		    &ds->ds_resume_offset[tx->tx_txg & TXG_MASK], tx));
1627 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
1628 		    ds->ds_object, DS_FIELD_RESUME_BYTES, 8, 1,
1629 		    &ds->ds_resume_bytes[tx->tx_txg & TXG_MASK], tx));
1630 		ds->ds_resume_object[tx->tx_txg & TXG_MASK] = 0;
1631 		ds->ds_resume_offset[tx->tx_txg & TXG_MASK] = 0;
1632 		ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] = 0;
1633 	}
1634 
1635 	dmu_objset_sync(ds->ds_objset, zio, tx);
1636 
1637 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1638 		if (ds->ds_feature_activation_needed[f]) {
1639 			if (ds->ds_feature_inuse[f])
1640 				continue;
1641 			dsl_dataset_activate_feature(ds->ds_object, f, tx);
1642 			ds->ds_feature_inuse[f] = B_TRUE;
1643 		}
1644 	}
1645 }
1646 
1647 static void
1648 get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
1649 {
1650 	uint64_t count = 0;
1651 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1652 	zap_cursor_t zc;
1653 	zap_attribute_t za;
1654 	nvlist_t *propval = fnvlist_alloc();
1655 	nvlist_t *val = fnvlist_alloc();
1656 
1657 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
1658 
1659 	/*
1660 	 * There may be missing entries in ds_next_clones_obj
1661 	 * due to a bug in a previous version of the code.
1662 	 * Only trust it if it has the right number of entries.
1663 	 */
1664 	if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
1665 		VERIFY0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
1666 		    &count));
1667 	}
1668 	if (count != dsl_dataset_phys(ds)->ds_num_children - 1)
1669 		goto fail;
1670 	for (zap_cursor_init(&zc, mos,
1671 	    dsl_dataset_phys(ds)->ds_next_clones_obj);
1672 	    zap_cursor_retrieve(&zc, &za) == 0;
1673 	    zap_cursor_advance(&zc)) {
1674 		dsl_dataset_t *clone;
1675 		char buf[ZFS_MAXNAMELEN];
1676 		VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
1677 		    za.za_first_integer, FTAG, &clone));
1678 		dsl_dir_name(clone->ds_dir, buf);
1679 		fnvlist_add_boolean(val, buf);
1680 		dsl_dataset_rele(clone, FTAG);
1681 	}
1682 	zap_cursor_fini(&zc);
1683 	fnvlist_add_nvlist(propval, ZPROP_VALUE, val);
1684 	fnvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES), propval);
1685 fail:
1686 	nvlist_free(val);
1687 	nvlist_free(propval);
1688 }
1689 
1690 static void
1691 get_receive_resume_stats(dsl_dataset_t *ds, nvlist_t *nv)
1692 {
1693 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1694 
1695 	if (dsl_dataset_has_resume_receive_state(ds)) {
1696 		char *str;
1697 		void *packed;
1698 		uint8_t *compressed;
1699 		uint64_t val;
1700 		nvlist_t *token_nv = fnvlist_alloc();
1701 		size_t packed_size, compressed_size;
1702 
1703 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1704 		    DS_FIELD_RESUME_FROMGUID, sizeof (val), 1, &val) == 0) {
1705 			fnvlist_add_uint64(token_nv, "fromguid", val);
1706 		}
1707 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1708 		    DS_FIELD_RESUME_OBJECT, sizeof (val), 1, &val) == 0) {
1709 			fnvlist_add_uint64(token_nv, "object", val);
1710 		}
1711 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1712 		    DS_FIELD_RESUME_OFFSET, sizeof (val), 1, &val) == 0) {
1713 			fnvlist_add_uint64(token_nv, "offset", val);
1714 		}
1715 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1716 		    DS_FIELD_RESUME_BYTES, sizeof (val), 1, &val) == 0) {
1717 			fnvlist_add_uint64(token_nv, "bytes", val);
1718 		}
1719 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1720 		    DS_FIELD_RESUME_TOGUID, sizeof (val), 1, &val) == 0) {
1721 			fnvlist_add_uint64(token_nv, "toguid", val);
1722 		}
1723 		char buf[256];
1724 		if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
1725 		    DS_FIELD_RESUME_TONAME, 1, sizeof (buf), buf) == 0) {
1726 			fnvlist_add_string(token_nv, "toname", buf);
1727 		}
1728 		if (zap_contains(dp->dp_meta_objset, ds->ds_object,
1729 		    DS_FIELD_RESUME_EMBEDOK) == 0) {
1730 			fnvlist_add_boolean(token_nv, "embedok");
1731 		}
1732 		packed = fnvlist_pack(token_nv, &packed_size);
1733 		fnvlist_free(token_nv);
1734 		compressed = kmem_alloc(packed_size, KM_SLEEP);
1735 
1736 		compressed_size = gzip_compress(packed, compressed,
1737 		    packed_size, packed_size, 6);
1738 
1739 		zio_cksum_t cksum;
1740 		fletcher_4_native(compressed, compressed_size, NULL, &cksum);
1741 
1742 		str = kmem_alloc(compressed_size * 2 + 1, KM_SLEEP);
1743 		for (int i = 0; i < compressed_size; i++) {
1744 			(void) sprintf(str + i * 2, "%02x", compressed[i]);
1745 		}
1746 		str[compressed_size * 2] = '\0';
1747 		char *propval = kmem_asprintf("%u-%llx-%llx-%s",
1748 		    ZFS_SEND_RESUME_TOKEN_VERSION,
1749 		    (longlong_t)cksum.zc_word[0],
1750 		    (longlong_t)packed_size, str);
1751 		dsl_prop_nvlist_add_string(nv,
1752 		    ZFS_PROP_RECEIVE_RESUME_TOKEN, propval);
1753 		kmem_free(packed, packed_size);
1754 		kmem_free(str, compressed_size * 2 + 1);
1755 		kmem_free(compressed, packed_size);
1756 		strfree(propval);
1757 	}
1758 }
1759 
1760 void
1761 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
1762 {
1763 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1764 	uint64_t refd, avail, uobjs, aobjs, ratio;
1765 
1766 	ASSERT(dsl_pool_config_held(dp));
1767 
1768 	ratio = dsl_dataset_phys(ds)->ds_compressed_bytes == 0 ? 100 :
1769 	    (dsl_dataset_phys(ds)->ds_uncompressed_bytes * 100 /
1770 	    dsl_dataset_phys(ds)->ds_compressed_bytes);
1771 
1772 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRATIO, ratio);
1773 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALREFERENCED,
1774 	    dsl_dataset_phys(ds)->ds_uncompressed_bytes);
1775 
1776 	if (ds->ds_is_snapshot) {
1777 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO, ratio);
1778 		dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
1779 		    dsl_dataset_phys(ds)->ds_unique_bytes);
1780 		get_clones_stat(ds, nv);
1781 	} else {
1782 		if (ds->ds_prev != NULL && ds->ds_prev != dp->dp_origin_snap) {
1783 			char buf[MAXNAMELEN];
1784 			dsl_dataset_name(ds->ds_prev, buf);
1785 			dsl_prop_nvlist_add_string(nv, ZFS_PROP_PREV_SNAP, buf);
1786 		}
1787 
1788 		dsl_dir_stats(ds->ds_dir, nv);
1789 	}
1790 
1791 	dsl_dataset_space(ds, &refd, &avail, &uobjs, &aobjs);
1792 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE, avail);
1793 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED, refd);
1794 
1795 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION,
1796 	    dsl_dataset_phys(ds)->ds_creation_time);
1797 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG,
1798 	    dsl_dataset_phys(ds)->ds_creation_txg);
1799 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA,
1800 	    ds->ds_quota);
1801 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION,
1802 	    ds->ds_reserved);
1803 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_GUID,
1804 	    dsl_dataset_phys(ds)->ds_guid);
1805 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_UNIQUE,
1806 	    dsl_dataset_phys(ds)->ds_unique_bytes);
1807 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_OBJSETID,
1808 	    ds->ds_object);
1809 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERREFS,
1810 	    ds->ds_userrefs);
1811 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
1812 	    DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
1813 
1814 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
1815 		uint64_t written, comp, uncomp;
1816 		dsl_pool_t *dp = ds->ds_dir->dd_pool;
1817 		dsl_dataset_t *prev;
1818 
1819 		int err = dsl_dataset_hold_obj(dp,
1820 		    dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
1821 		if (err == 0) {
1822 			err = dsl_dataset_space_written(prev, ds, &written,
1823 			    &comp, &uncomp);
1824 			dsl_dataset_rele(prev, FTAG);
1825 			if (err == 0) {
1826 				dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
1827 				    written);
1828 			}
1829 		}
1830 	}
1831 
1832 	if (!dsl_dataset_is_snapshot(ds)) {
1833 		/*
1834 		 * A failed "newfs" (e.g. full) resumable receive leaves
1835 		 * the stats set on this dataset.  Check here for the prop.
1836 		 */
1837 		get_receive_resume_stats(ds, nv);
1838 
1839 		/*
1840 		 * A failed incremental resumable receive leaves the
1841 		 * stats set on our child named "%recv".  Check the child
1842 		 * for the prop.
1843 		 */
1844 		char recvname[ZFS_MAXNAMELEN];
1845 		dsl_dataset_t *recv_ds;
1846 		dsl_dataset_name(ds, recvname);
1847 		(void) strcat(recvname, "/");
1848 		(void) strcat(recvname, recv_clone_name);
1849 		if (dsl_dataset_hold(dp, recvname, FTAG, &recv_ds) == 0) {
1850 			get_receive_resume_stats(recv_ds, nv);
1851 			dsl_dataset_rele(recv_ds, FTAG);
1852 		}
1853 	}
1854 }
1855 
1856 void
1857 dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat)
1858 {
1859 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1860 	ASSERT(dsl_pool_config_held(dp));
1861 
1862 	stat->dds_creation_txg = dsl_dataset_phys(ds)->ds_creation_txg;
1863 	stat->dds_inconsistent =
1864 	    dsl_dataset_phys(ds)->ds_flags & DS_FLAG_INCONSISTENT;
1865 	stat->dds_guid = dsl_dataset_phys(ds)->ds_guid;
1866 	stat->dds_origin[0] = '\0';
1867 	if (ds->ds_is_snapshot) {
1868 		stat->dds_is_snapshot = B_TRUE;
1869 		stat->dds_num_clones =
1870 		    dsl_dataset_phys(ds)->ds_num_children - 1;
1871 	} else {
1872 		stat->dds_is_snapshot = B_FALSE;
1873 		stat->dds_num_clones = 0;
1874 
1875 		if (dsl_dir_is_clone(ds->ds_dir)) {
1876 			dsl_dataset_t *ods;
1877 
1878 			VERIFY0(dsl_dataset_hold_obj(dp,
1879 			    dsl_dir_phys(ds->ds_dir)->dd_origin_obj,
1880 			    FTAG, &ods));
1881 			dsl_dataset_name(ods, stat->dds_origin);
1882 			dsl_dataset_rele(ods, FTAG);
1883 		}
1884 	}
1885 }
1886 
1887 uint64_t
1888 dsl_dataset_fsid_guid(dsl_dataset_t *ds)
1889 {
1890 	return (ds->ds_fsid_guid);
1891 }
1892 
1893 void
1894 dsl_dataset_space(dsl_dataset_t *ds,
1895     uint64_t *refdbytesp, uint64_t *availbytesp,
1896     uint64_t *usedobjsp, uint64_t *availobjsp)
1897 {
1898 	*refdbytesp = dsl_dataset_phys(ds)->ds_referenced_bytes;
1899 	*availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE);
1900 	if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes)
1901 		*availbytesp +=
1902 		    ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes;
1903 	if (ds->ds_quota != 0) {
1904 		/*
1905 		 * Adjust available bytes according to refquota
1906 		 */
1907 		if (*refdbytesp < ds->ds_quota)
1908 			*availbytesp = MIN(*availbytesp,
1909 			    ds->ds_quota - *refdbytesp);
1910 		else
1911 			*availbytesp = 0;
1912 	}
1913 	*usedobjsp = BP_GET_FILL(&dsl_dataset_phys(ds)->ds_bp);
1914 	*availobjsp = DN_MAX_OBJECT - *usedobjsp;
1915 }
1916 
1917 boolean_t
1918 dsl_dataset_modified_since_snap(dsl_dataset_t *ds, dsl_dataset_t *snap)
1919 {
1920 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1921 
1922 	ASSERT(dsl_pool_config_held(dp));
1923 	if (snap == NULL)
1924 		return (B_FALSE);
1925 	if (dsl_dataset_phys(ds)->ds_bp.blk_birth >
1926 	    dsl_dataset_phys(snap)->ds_creation_txg) {
1927 		objset_t *os, *os_snap;
1928 		/*
1929 		 * It may be that only the ZIL differs, because it was
1930 		 * reset in the head.  Don't count that as being
1931 		 * modified.
1932 		 */
1933 		if (dmu_objset_from_ds(ds, &os) != 0)
1934 			return (B_TRUE);
1935 		if (dmu_objset_from_ds(snap, &os_snap) != 0)
1936 			return (B_TRUE);
1937 		return (bcmp(&os->os_phys->os_meta_dnode,
1938 		    &os_snap->os_phys->os_meta_dnode,
1939 		    sizeof (os->os_phys->os_meta_dnode)) != 0);
1940 	}
1941 	return (B_FALSE);
1942 }
1943 
1944 typedef struct dsl_dataset_rename_snapshot_arg {
1945 	const char *ddrsa_fsname;
1946 	const char *ddrsa_oldsnapname;
1947 	const char *ddrsa_newsnapname;
1948 	boolean_t ddrsa_recursive;
1949 	dmu_tx_t *ddrsa_tx;
1950 } dsl_dataset_rename_snapshot_arg_t;
1951 
1952 /* ARGSUSED */
1953 static int
1954 dsl_dataset_rename_snapshot_check_impl(dsl_pool_t *dp,
1955     dsl_dataset_t *hds, void *arg)
1956 {
1957 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1958 	int error;
1959 	uint64_t val;
1960 
1961 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
1962 	if (error != 0) {
1963 		/* ignore nonexistent snapshots */
1964 		return (error == ENOENT ? 0 : error);
1965 	}
1966 
1967 	/* new name should not exist */
1968 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_newsnapname, &val);
1969 	if (error == 0)
1970 		error = SET_ERROR(EEXIST);
1971 	else if (error == ENOENT)
1972 		error = 0;
1973 
1974 	/* dataset name + 1 for the "@" + the new snapshot name must fit */
1975 	if (dsl_dir_namelen(hds->ds_dir) + 1 +
1976 	    strlen(ddrsa->ddrsa_newsnapname) >= MAXNAMELEN)
1977 		error = SET_ERROR(ENAMETOOLONG);
1978 
1979 	return (error);
1980 }
1981 
1982 static int
1983 dsl_dataset_rename_snapshot_check(void *arg, dmu_tx_t *tx)
1984 {
1985 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
1986 	dsl_pool_t *dp = dmu_tx_pool(tx);
1987 	dsl_dataset_t *hds;
1988 	int error;
1989 
1990 	error = dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds);
1991 	if (error != 0)
1992 		return (error);
1993 
1994 	if (ddrsa->ddrsa_recursive) {
1995 		error = dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
1996 		    dsl_dataset_rename_snapshot_check_impl, ddrsa,
1997 		    DS_FIND_CHILDREN);
1998 	} else {
1999 		error = dsl_dataset_rename_snapshot_check_impl(dp, hds, ddrsa);
2000 	}
2001 	dsl_dataset_rele(hds, FTAG);
2002 	return (error);
2003 }
2004 
2005 static int
2006 dsl_dataset_rename_snapshot_sync_impl(dsl_pool_t *dp,
2007     dsl_dataset_t *hds, void *arg)
2008 {
2009 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2010 	dsl_dataset_t *ds;
2011 	uint64_t val;
2012 	dmu_tx_t *tx = ddrsa->ddrsa_tx;
2013 	int error;
2014 
2015 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
2016 	ASSERT(error == 0 || error == ENOENT);
2017 	if (error == ENOENT) {
2018 		/* ignore nonexistent snapshots */
2019 		return (0);
2020 	}
2021 
2022 	VERIFY0(dsl_dataset_hold_obj(dp, val, FTAG, &ds));
2023 
2024 	/* log before we change the name */
2025 	spa_history_log_internal_ds(ds, "rename", tx,
2026 	    "-> @%s", ddrsa->ddrsa_newsnapname);
2027 
2028 	VERIFY0(dsl_dataset_snap_remove(hds, ddrsa->ddrsa_oldsnapname, tx,
2029 	    B_FALSE));
2030 	mutex_enter(&ds->ds_lock);
2031 	(void) strcpy(ds->ds_snapname, ddrsa->ddrsa_newsnapname);
2032 	mutex_exit(&ds->ds_lock);
2033 	VERIFY0(zap_add(dp->dp_meta_objset,
2034 	    dsl_dataset_phys(hds)->ds_snapnames_zapobj,
2035 	    ds->ds_snapname, 8, 1, &ds->ds_object, tx));
2036 
2037 	dsl_dataset_rele(ds, FTAG);
2038 	return (0);
2039 }
2040 
2041 static void
2042 dsl_dataset_rename_snapshot_sync(void *arg, dmu_tx_t *tx)
2043 {
2044 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2045 	dsl_pool_t *dp = dmu_tx_pool(tx);
2046 	dsl_dataset_t *hds;
2047 
2048 	VERIFY0(dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds));
2049 	ddrsa->ddrsa_tx = tx;
2050 	if (ddrsa->ddrsa_recursive) {
2051 		VERIFY0(dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
2052 		    dsl_dataset_rename_snapshot_sync_impl, ddrsa,
2053 		    DS_FIND_CHILDREN));
2054 	} else {
2055 		VERIFY0(dsl_dataset_rename_snapshot_sync_impl(dp, hds, ddrsa));
2056 	}
2057 	dsl_dataset_rele(hds, FTAG);
2058 }
2059 
2060 int
2061 dsl_dataset_rename_snapshot(const char *fsname,
2062     const char *oldsnapname, const char *newsnapname, boolean_t recursive)
2063 {
2064 	dsl_dataset_rename_snapshot_arg_t ddrsa;
2065 
2066 	ddrsa.ddrsa_fsname = fsname;
2067 	ddrsa.ddrsa_oldsnapname = oldsnapname;
2068 	ddrsa.ddrsa_newsnapname = newsnapname;
2069 	ddrsa.ddrsa_recursive = recursive;
2070 
2071 	return (dsl_sync_task(fsname, dsl_dataset_rename_snapshot_check,
2072 	    dsl_dataset_rename_snapshot_sync, &ddrsa,
2073 	    1, ZFS_SPACE_CHECK_RESERVED));
2074 }
2075 
2076 /*
2077  * If we're doing an ownership handoff, we need to make sure that there is
2078  * only one long hold on the dataset.  We're not allowed to change anything here
2079  * so we don't permanently release the long hold or regular hold here.  We want
2080  * to do this only when syncing to avoid the dataset unexpectedly going away
2081  * when we release the long hold.
2082  */
2083 static int
2084 dsl_dataset_handoff_check(dsl_dataset_t *ds, void *owner, dmu_tx_t *tx)
2085 {
2086 	boolean_t held;
2087 
2088 	if (!dmu_tx_is_syncing(tx))
2089 		return (0);
2090 
2091 	if (owner != NULL) {
2092 		VERIFY3P(ds->ds_owner, ==, owner);
2093 		dsl_dataset_long_rele(ds, owner);
2094 	}
2095 
2096 	held = dsl_dataset_long_held(ds);
2097 
2098 	if (owner != NULL)
2099 		dsl_dataset_long_hold(ds, owner);
2100 
2101 	if (held)
2102 		return (SET_ERROR(EBUSY));
2103 
2104 	return (0);
2105 }
2106 
2107 typedef struct dsl_dataset_rollback_arg {
2108 	const char *ddra_fsname;
2109 	void *ddra_owner;
2110 	nvlist_t *ddra_result;
2111 } dsl_dataset_rollback_arg_t;
2112 
2113 static int
2114 dsl_dataset_rollback_check(void *arg, dmu_tx_t *tx)
2115 {
2116 	dsl_dataset_rollback_arg_t *ddra = arg;
2117 	dsl_pool_t *dp = dmu_tx_pool(tx);
2118 	dsl_dataset_t *ds;
2119 	int64_t unused_refres_delta;
2120 	int error;
2121 
2122 	error = dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds);
2123 	if (error != 0)
2124 		return (error);
2125 
2126 	/* must not be a snapshot */
2127 	if (ds->ds_is_snapshot) {
2128 		dsl_dataset_rele(ds, FTAG);
2129 		return (SET_ERROR(EINVAL));
2130 	}
2131 
2132 	/* must have a most recent snapshot */
2133 	if (dsl_dataset_phys(ds)->ds_prev_snap_txg < TXG_INITIAL) {
2134 		dsl_dataset_rele(ds, FTAG);
2135 		return (SET_ERROR(EINVAL));
2136 	}
2137 
2138 	/* must not have any bookmarks after the most recent snapshot */
2139 	nvlist_t *proprequest = fnvlist_alloc();
2140 	fnvlist_add_boolean(proprequest, zfs_prop_to_name(ZFS_PROP_CREATETXG));
2141 	nvlist_t *bookmarks = fnvlist_alloc();
2142 	error = dsl_get_bookmarks_impl(ds, proprequest, bookmarks);
2143 	fnvlist_free(proprequest);
2144 	if (error != 0)
2145 		return (error);
2146 	for (nvpair_t *pair = nvlist_next_nvpair(bookmarks, NULL);
2147 	    pair != NULL; pair = nvlist_next_nvpair(bookmarks, pair)) {
2148 		nvlist_t *valuenv =
2149 		    fnvlist_lookup_nvlist(fnvpair_value_nvlist(pair),
2150 		    zfs_prop_to_name(ZFS_PROP_CREATETXG));
2151 		uint64_t createtxg = fnvlist_lookup_uint64(valuenv, "value");
2152 		if (createtxg > dsl_dataset_phys(ds)->ds_prev_snap_txg) {
2153 			fnvlist_free(bookmarks);
2154 			dsl_dataset_rele(ds, FTAG);
2155 			return (SET_ERROR(EEXIST));
2156 		}
2157 	}
2158 	fnvlist_free(bookmarks);
2159 
2160 	error = dsl_dataset_handoff_check(ds, ddra->ddra_owner, tx);
2161 	if (error != 0) {
2162 		dsl_dataset_rele(ds, FTAG);
2163 		return (error);
2164 	}
2165 
2166 	/*
2167 	 * Check if the snap we are rolling back to uses more than
2168 	 * the refquota.
2169 	 */
2170 	if (ds->ds_quota != 0 &&
2171 	    dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes > ds->ds_quota) {
2172 		dsl_dataset_rele(ds, FTAG);
2173 		return (SET_ERROR(EDQUOT));
2174 	}
2175 
2176 	/*
2177 	 * When we do the clone swap, we will temporarily use more space
2178 	 * due to the refreservation (the head will no longer have any
2179 	 * unique space, so the entire amount of the refreservation will need
2180 	 * to be free).  We will immediately destroy the clone, freeing
2181 	 * this space, but the freeing happens over many txg's.
2182 	 */
2183 	unused_refres_delta = (int64_t)MIN(ds->ds_reserved,
2184 	    dsl_dataset_phys(ds)->ds_unique_bytes);
2185 
2186 	if (unused_refres_delta > 0 &&
2187 	    unused_refres_delta >
2188 	    dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) {
2189 		dsl_dataset_rele(ds, FTAG);
2190 		return (SET_ERROR(ENOSPC));
2191 	}
2192 
2193 	dsl_dataset_rele(ds, FTAG);
2194 	return (0);
2195 }
2196 
2197 static void
2198 dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
2199 {
2200 	dsl_dataset_rollback_arg_t *ddra = arg;
2201 	dsl_pool_t *dp = dmu_tx_pool(tx);
2202 	dsl_dataset_t *ds, *clone;
2203 	uint64_t cloneobj;
2204 	char namebuf[ZFS_MAXNAMELEN];
2205 
2206 	VERIFY0(dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds));
2207 
2208 	dsl_dataset_name(ds->ds_prev, namebuf);
2209 	fnvlist_add_string(ddra->ddra_result, "target", namebuf);
2210 
2211 	cloneobj = dsl_dataset_create_sync(ds->ds_dir, "%rollback",
2212 	    ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, tx);
2213 
2214 	VERIFY0(dsl_dataset_hold_obj(dp, cloneobj, FTAG, &clone));
2215 
2216 	dsl_dataset_clone_swap_sync_impl(clone, ds, tx);
2217 	dsl_dataset_zero_zil(ds, tx);
2218 
2219 	dsl_destroy_head_sync_impl(clone, tx);
2220 
2221 	dsl_dataset_rele(clone, FTAG);
2222 	dsl_dataset_rele(ds, FTAG);
2223 }
2224 
2225 /*
2226  * Rolls back the given filesystem or volume to the most recent snapshot.
2227  * The name of the most recent snapshot will be returned under key "target"
2228  * in the result nvlist.
2229  *
2230  * If owner != NULL:
2231  * - The existing dataset MUST be owned by the specified owner at entry
2232  * - Upon return, dataset will still be held by the same owner, whether we
2233  *   succeed or not.
2234  *
2235  * This mode is required any time the existing filesystem is mounted.  See
2236  * notes above zfs_suspend_fs() for further details.
2237  */
2238 int
2239 dsl_dataset_rollback(const char *fsname, void *owner, nvlist_t *result)
2240 {
2241 	dsl_dataset_rollback_arg_t ddra;
2242 
2243 	ddra.ddra_fsname = fsname;
2244 	ddra.ddra_owner = owner;
2245 	ddra.ddra_result = result;
2246 
2247 	return (dsl_sync_task(fsname, dsl_dataset_rollback_check,
2248 	    dsl_dataset_rollback_sync, &ddra,
2249 	    1, ZFS_SPACE_CHECK_RESERVED));
2250 }
2251 
2252 struct promotenode {
2253 	list_node_t link;
2254 	dsl_dataset_t *ds;
2255 };
2256 
2257 typedef struct dsl_dataset_promote_arg {
2258 	const char *ddpa_clonename;
2259 	dsl_dataset_t *ddpa_clone;
2260 	list_t shared_snaps, origin_snaps, clone_snaps;
2261 	dsl_dataset_t *origin_origin; /* origin of the origin */
2262 	uint64_t used, comp, uncomp, unique, cloneusedsnap, originusedsnap;
2263 	char *err_ds;
2264 	cred_t *cr;
2265 } dsl_dataset_promote_arg_t;
2266 
2267 static int snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep);
2268 static int promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp,
2269     void *tag);
2270 static void promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag);
2271 
2272 static int
2273 dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
2274 {
2275 	dsl_dataset_promote_arg_t *ddpa = arg;
2276 	dsl_pool_t *dp = dmu_tx_pool(tx);
2277 	dsl_dataset_t *hds;
2278 	struct promotenode *snap;
2279 	dsl_dataset_t *origin_ds;
2280 	int err;
2281 	uint64_t unused;
2282 	uint64_t ss_mv_cnt;
2283 	size_t max_snap_len;
2284 
2285 	err = promote_hold(ddpa, dp, FTAG);
2286 	if (err != 0)
2287 		return (err);
2288 
2289 	hds = ddpa->ddpa_clone;
2290 	max_snap_len = MAXNAMELEN - strlen(ddpa->ddpa_clonename) - 1;
2291 
2292 	if (dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE) {
2293 		promote_rele(ddpa, FTAG);
2294 		return (SET_ERROR(EXDEV));
2295 	}
2296 
2297 	/*
2298 	 * Compute and check the amount of space to transfer.  Since this is
2299 	 * so expensive, don't do the preliminary check.
2300 	 */
2301 	if (!dmu_tx_is_syncing(tx)) {
2302 		promote_rele(ddpa, FTAG);
2303 		return (0);
2304 	}
2305 
2306 	snap = list_head(&ddpa->shared_snaps);
2307 	origin_ds = snap->ds;
2308 
2309 	/* compute origin's new unique space */
2310 	snap = list_tail(&ddpa->clone_snaps);
2311 	ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
2312 	    origin_ds->ds_object);
2313 	dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2314 	    dsl_dataset_phys(origin_ds)->ds_prev_snap_txg, UINT64_MAX,
2315 	    &ddpa->unique, &unused, &unused);
2316 
2317 	/*
2318 	 * Walk the snapshots that we are moving
2319 	 *
2320 	 * Compute space to transfer.  Consider the incremental changes
2321 	 * to used by each snapshot:
2322 	 * (my used) = (prev's used) + (blocks born) - (blocks killed)
2323 	 * So each snapshot gave birth to:
2324 	 * (blocks born) = (my used) - (prev's used) + (blocks killed)
2325 	 * So a sequence would look like:
2326 	 * (uN - u(N-1) + kN) + ... + (u1 - u0 + k1) + (u0 - 0 + k0)
2327 	 * Which simplifies to:
2328 	 * uN + kN + kN-1 + ... + k1 + k0
2329 	 * Note however, if we stop before we reach the ORIGIN we get:
2330 	 * uN + kN + kN-1 + ... + kM - uM-1
2331 	 */
2332 	ss_mv_cnt = 0;
2333 	ddpa->used = dsl_dataset_phys(origin_ds)->ds_referenced_bytes;
2334 	ddpa->comp = dsl_dataset_phys(origin_ds)->ds_compressed_bytes;
2335 	ddpa->uncomp = dsl_dataset_phys(origin_ds)->ds_uncompressed_bytes;
2336 	for (snap = list_head(&ddpa->shared_snaps); snap;
2337 	    snap = list_next(&ddpa->shared_snaps, snap)) {
2338 		uint64_t val, dlused, dlcomp, dluncomp;
2339 		dsl_dataset_t *ds = snap->ds;
2340 
2341 		ss_mv_cnt++;
2342 
2343 		/*
2344 		 * If there are long holds, we won't be able to evict
2345 		 * the objset.
2346 		 */
2347 		if (dsl_dataset_long_held(ds)) {
2348 			err = SET_ERROR(EBUSY);
2349 			goto out;
2350 		}
2351 
2352 		/* Check that the snapshot name does not conflict */
2353 		VERIFY0(dsl_dataset_get_snapname(ds));
2354 		if (strlen(ds->ds_snapname) >= max_snap_len) {
2355 			err = SET_ERROR(ENAMETOOLONG);
2356 			goto out;
2357 		}
2358 		err = dsl_dataset_snap_lookup(hds, ds->ds_snapname, &val);
2359 		if (err == 0) {
2360 			(void) strcpy(ddpa->err_ds, snap->ds->ds_snapname);
2361 			err = SET_ERROR(EEXIST);
2362 			goto out;
2363 		}
2364 		if (err != ENOENT)
2365 			goto out;
2366 
2367 		/* The very first snapshot does not have a deadlist */
2368 		if (dsl_dataset_phys(ds)->ds_prev_snap_obj == 0)
2369 			continue;
2370 
2371 		dsl_deadlist_space(&ds->ds_deadlist,
2372 		    &dlused, &dlcomp, &dluncomp);
2373 		ddpa->used += dlused;
2374 		ddpa->comp += dlcomp;
2375 		ddpa->uncomp += dluncomp;
2376 	}
2377 
2378 	/*
2379 	 * If we are a clone of a clone then we never reached ORIGIN,
2380 	 * so we need to subtract out the clone origin's used space.
2381 	 */
2382 	if (ddpa->origin_origin) {
2383 		ddpa->used -=
2384 		    dsl_dataset_phys(ddpa->origin_origin)->ds_referenced_bytes;
2385 		ddpa->comp -=
2386 		    dsl_dataset_phys(ddpa->origin_origin)->ds_compressed_bytes;
2387 		ddpa->uncomp -=
2388 		    dsl_dataset_phys(ddpa->origin_origin)->
2389 		    ds_uncompressed_bytes;
2390 	}
2391 
2392 	/* Check that there is enough space and limit headroom here */
2393 	err = dsl_dir_transfer_possible(origin_ds->ds_dir, hds->ds_dir,
2394 	    0, ss_mv_cnt, ddpa->used, ddpa->cr);
2395 	if (err != 0)
2396 		goto out;
2397 
2398 	/*
2399 	 * Compute the amounts of space that will be used by snapshots
2400 	 * after the promotion (for both origin and clone).  For each,
2401 	 * it is the amount of space that will be on all of their
2402 	 * deadlists (that was not born before their new origin).
2403 	 */
2404 	if (dsl_dir_phys(hds->ds_dir)->dd_flags & DD_FLAG_USED_BREAKDOWN) {
2405 		uint64_t space;
2406 
2407 		/*
2408 		 * Note, typically this will not be a clone of a clone,
2409 		 * so dd_origin_txg will be < TXG_INITIAL, so
2410 		 * these snaplist_space() -> dsl_deadlist_space_range()
2411 		 * calls will be fast because they do not have to
2412 		 * iterate over all bps.
2413 		 */
2414 		snap = list_head(&ddpa->origin_snaps);
2415 		err = snaplist_space(&ddpa->shared_snaps,
2416 		    snap->ds->ds_dir->dd_origin_txg, &ddpa->cloneusedsnap);
2417 		if (err != 0)
2418 			goto out;
2419 
2420 		err = snaplist_space(&ddpa->clone_snaps,
2421 		    snap->ds->ds_dir->dd_origin_txg, &space);
2422 		if (err != 0)
2423 			goto out;
2424 		ddpa->cloneusedsnap += space;
2425 	}
2426 	if (dsl_dir_phys(origin_ds->ds_dir)->dd_flags &
2427 	    DD_FLAG_USED_BREAKDOWN) {
2428 		err = snaplist_space(&ddpa->origin_snaps,
2429 		    dsl_dataset_phys(origin_ds)->ds_creation_txg,
2430 		    &ddpa->originusedsnap);
2431 		if (err != 0)
2432 			goto out;
2433 	}
2434 
2435 out:
2436 	promote_rele(ddpa, FTAG);
2437 	return (err);
2438 }
2439 
2440 static void
2441 dsl_dataset_promote_sync(void *arg, dmu_tx_t *tx)
2442 {
2443 	dsl_dataset_promote_arg_t *ddpa = arg;
2444 	dsl_pool_t *dp = dmu_tx_pool(tx);
2445 	dsl_dataset_t *hds;
2446 	struct promotenode *snap;
2447 	dsl_dataset_t *origin_ds;
2448 	dsl_dataset_t *origin_head;
2449 	dsl_dir_t *dd;
2450 	dsl_dir_t *odd = NULL;
2451 	uint64_t oldnext_obj;
2452 	int64_t delta;
2453 
2454 	VERIFY0(promote_hold(ddpa, dp, FTAG));
2455 	hds = ddpa->ddpa_clone;
2456 
2457 	ASSERT0(dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE);
2458 
2459 	snap = list_head(&ddpa->shared_snaps);
2460 	origin_ds = snap->ds;
2461 	dd = hds->ds_dir;
2462 
2463 	snap = list_head(&ddpa->origin_snaps);
2464 	origin_head = snap->ds;
2465 
2466 	/*
2467 	 * We need to explicitly open odd, since origin_ds's dd will be
2468 	 * changing.
2469 	 */
2470 	VERIFY0(dsl_dir_hold_obj(dp, origin_ds->ds_dir->dd_object,
2471 	    NULL, FTAG, &odd));
2472 
2473 	/* change origin's next snap */
2474 	dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
2475 	oldnext_obj = dsl_dataset_phys(origin_ds)->ds_next_snap_obj;
2476 	snap = list_tail(&ddpa->clone_snaps);
2477 	ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
2478 	    origin_ds->ds_object);
2479 	dsl_dataset_phys(origin_ds)->ds_next_snap_obj = snap->ds->ds_object;
2480 
2481 	/* change the origin's next clone */
2482 	if (dsl_dataset_phys(origin_ds)->ds_next_clones_obj) {
2483 		dsl_dataset_remove_from_next_clones(origin_ds,
2484 		    snap->ds->ds_object, tx);
2485 		VERIFY0(zap_add_int(dp->dp_meta_objset,
2486 		    dsl_dataset_phys(origin_ds)->ds_next_clones_obj,
2487 		    oldnext_obj, tx));
2488 	}
2489 
2490 	/* change origin */
2491 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
2492 	ASSERT3U(dsl_dir_phys(dd)->dd_origin_obj, ==, origin_ds->ds_object);
2493 	dsl_dir_phys(dd)->dd_origin_obj = dsl_dir_phys(odd)->dd_origin_obj;
2494 	dd->dd_origin_txg = origin_head->ds_dir->dd_origin_txg;
2495 	dmu_buf_will_dirty(odd->dd_dbuf, tx);
2496 	dsl_dir_phys(odd)->dd_origin_obj = origin_ds->ds_object;
2497 	origin_head->ds_dir->dd_origin_txg =
2498 	    dsl_dataset_phys(origin_ds)->ds_creation_txg;
2499 
2500 	/* change dd_clone entries */
2501 	if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2502 		VERIFY0(zap_remove_int(dp->dp_meta_objset,
2503 		    dsl_dir_phys(odd)->dd_clones, hds->ds_object, tx));
2504 		VERIFY0(zap_add_int(dp->dp_meta_objset,
2505 		    dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
2506 		    hds->ds_object, tx));
2507 
2508 		VERIFY0(zap_remove_int(dp->dp_meta_objset,
2509 		    dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
2510 		    origin_head->ds_object, tx));
2511 		if (dsl_dir_phys(dd)->dd_clones == 0) {
2512 			dsl_dir_phys(dd)->dd_clones =
2513 			    zap_create(dp->dp_meta_objset, DMU_OT_DSL_CLONES,
2514 			    DMU_OT_NONE, 0, tx);
2515 		}
2516 		VERIFY0(zap_add_int(dp->dp_meta_objset,
2517 		    dsl_dir_phys(dd)->dd_clones, origin_head->ds_object, tx));
2518 	}
2519 
2520 	/* move snapshots to this dir */
2521 	for (snap = list_head(&ddpa->shared_snaps); snap;
2522 	    snap = list_next(&ddpa->shared_snaps, snap)) {
2523 		dsl_dataset_t *ds = snap->ds;
2524 
2525 		/*
2526 		 * Property callbacks are registered to a particular
2527 		 * dsl_dir.  Since ours is changing, evict the objset
2528 		 * so that they will be unregistered from the old dsl_dir.
2529 		 */
2530 		if (ds->ds_objset) {
2531 			dmu_objset_evict(ds->ds_objset);
2532 			ds->ds_objset = NULL;
2533 		}
2534 
2535 		/* move snap name entry */
2536 		VERIFY0(dsl_dataset_get_snapname(ds));
2537 		VERIFY0(dsl_dataset_snap_remove(origin_head,
2538 		    ds->ds_snapname, tx, B_TRUE));
2539 		VERIFY0(zap_add(dp->dp_meta_objset,
2540 		    dsl_dataset_phys(hds)->ds_snapnames_zapobj, ds->ds_snapname,
2541 		    8, 1, &ds->ds_object, tx));
2542 		dsl_fs_ss_count_adjust(hds->ds_dir, 1,
2543 		    DD_FIELD_SNAPSHOT_COUNT, tx);
2544 
2545 		/* change containing dsl_dir */
2546 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
2547 		ASSERT3U(dsl_dataset_phys(ds)->ds_dir_obj, ==, odd->dd_object);
2548 		dsl_dataset_phys(ds)->ds_dir_obj = dd->dd_object;
2549 		ASSERT3P(ds->ds_dir, ==, odd);
2550 		dsl_dir_rele(ds->ds_dir, ds);
2551 		VERIFY0(dsl_dir_hold_obj(dp, dd->dd_object,
2552 		    NULL, ds, &ds->ds_dir));
2553 
2554 		/* move any clone references */
2555 		if (dsl_dataset_phys(ds)->ds_next_clones_obj &&
2556 		    spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
2557 			zap_cursor_t zc;
2558 			zap_attribute_t za;
2559 
2560 			for (zap_cursor_init(&zc, dp->dp_meta_objset,
2561 			    dsl_dataset_phys(ds)->ds_next_clones_obj);
2562 			    zap_cursor_retrieve(&zc, &za) == 0;
2563 			    zap_cursor_advance(&zc)) {
2564 				dsl_dataset_t *cnds;
2565 				uint64_t o;
2566 
2567 				if (za.za_first_integer == oldnext_obj) {
2568 					/*
2569 					 * We've already moved the
2570 					 * origin's reference.
2571 					 */
2572 					continue;
2573 				}
2574 
2575 				VERIFY0(dsl_dataset_hold_obj(dp,
2576 				    za.za_first_integer, FTAG, &cnds));
2577 				o = dsl_dir_phys(cnds->ds_dir)->
2578 				    dd_head_dataset_obj;
2579 
2580 				VERIFY0(zap_remove_int(dp->dp_meta_objset,
2581 				    dsl_dir_phys(odd)->dd_clones, o, tx));
2582 				VERIFY0(zap_add_int(dp->dp_meta_objset,
2583 				    dsl_dir_phys(dd)->dd_clones, o, tx));
2584 				dsl_dataset_rele(cnds, FTAG);
2585 			}
2586 			zap_cursor_fini(&zc);
2587 		}
2588 
2589 		ASSERT(!dsl_prop_hascb(ds));
2590 	}
2591 
2592 	/*
2593 	 * Change space accounting.
2594 	 * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either
2595 	 * both be valid, or both be 0 (resulting in delta == 0).  This
2596 	 * is true for each of {clone,origin} independently.
2597 	 */
2598 
2599 	delta = ddpa->cloneusedsnap -
2600 	    dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_SNAP];
2601 	ASSERT3S(delta, >=, 0);
2602 	ASSERT3U(ddpa->used, >=, delta);
2603 	dsl_dir_diduse_space(dd, DD_USED_SNAP, delta, 0, 0, tx);
2604 	dsl_dir_diduse_space(dd, DD_USED_HEAD,
2605 	    ddpa->used - delta, ddpa->comp, ddpa->uncomp, tx);
2606 
2607 	delta = ddpa->originusedsnap -
2608 	    dsl_dir_phys(odd)->dd_used_breakdown[DD_USED_SNAP];
2609 	ASSERT3S(delta, <=, 0);
2610 	ASSERT3U(ddpa->used, >=, -delta);
2611 	dsl_dir_diduse_space(odd, DD_USED_SNAP, delta, 0, 0, tx);
2612 	dsl_dir_diduse_space(odd, DD_USED_HEAD,
2613 	    -ddpa->used - delta, -ddpa->comp, -ddpa->uncomp, tx);
2614 
2615 	dsl_dataset_phys(origin_ds)->ds_unique_bytes = ddpa->unique;
2616 
2617 	/* log history record */
2618 	spa_history_log_internal_ds(hds, "promote", tx, "");
2619 
2620 	dsl_dir_rele(odd, FTAG);
2621 	promote_rele(ddpa, FTAG);
2622 }
2623 
2624 /*
2625  * Make a list of dsl_dataset_t's for the snapshots between first_obj
2626  * (exclusive) and last_obj (inclusive).  The list will be in reverse
2627  * order (last_obj will be the list_head()).  If first_obj == 0, do all
2628  * snapshots back to this dataset's origin.
2629  */
2630 static int
2631 snaplist_make(dsl_pool_t *dp,
2632     uint64_t first_obj, uint64_t last_obj, list_t *l, void *tag)
2633 {
2634 	uint64_t obj = last_obj;
2635 
2636 	list_create(l, sizeof (struct promotenode),
2637 	    offsetof(struct promotenode, link));
2638 
2639 	while (obj != first_obj) {
2640 		dsl_dataset_t *ds;
2641 		struct promotenode *snap;
2642 		int err;
2643 
2644 		err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
2645 		ASSERT(err != ENOENT);
2646 		if (err != 0)
2647 			return (err);
2648 
2649 		if (first_obj == 0)
2650 			first_obj = dsl_dir_phys(ds->ds_dir)->dd_origin_obj;
2651 
2652 		snap = kmem_alloc(sizeof (*snap), KM_SLEEP);
2653 		snap->ds = ds;
2654 		list_insert_tail(l, snap);
2655 		obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
2656 	}
2657 
2658 	return (0);
2659 }
2660 
2661 static int
2662 snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep)
2663 {
2664 	struct promotenode *snap;
2665 
2666 	*spacep = 0;
2667 	for (snap = list_head(l); snap; snap = list_next(l, snap)) {
2668 		uint64_t used, comp, uncomp;
2669 		dsl_deadlist_space_range(&snap->ds->ds_deadlist,
2670 		    mintxg, UINT64_MAX, &used, &comp, &uncomp);
2671 		*spacep += used;
2672 	}
2673 	return (0);
2674 }
2675 
2676 static void
2677 snaplist_destroy(list_t *l, void *tag)
2678 {
2679 	struct promotenode *snap;
2680 
2681 	if (l == NULL || !list_link_active(&l->list_head))
2682 		return;
2683 
2684 	while ((snap = list_tail(l)) != NULL) {
2685 		list_remove(l, snap);
2686 		dsl_dataset_rele(snap->ds, tag);
2687 		kmem_free(snap, sizeof (*snap));
2688 	}
2689 	list_destroy(l);
2690 }
2691 
2692 static int
2693 promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp, void *tag)
2694 {
2695 	int error;
2696 	dsl_dir_t *dd;
2697 	struct promotenode *snap;
2698 
2699 	error = dsl_dataset_hold(dp, ddpa->ddpa_clonename, tag,
2700 	    &ddpa->ddpa_clone);
2701 	if (error != 0)
2702 		return (error);
2703 	dd = ddpa->ddpa_clone->ds_dir;
2704 
2705 	if (ddpa->ddpa_clone->ds_is_snapshot ||
2706 	    !dsl_dir_is_clone(dd)) {
2707 		dsl_dataset_rele(ddpa->ddpa_clone, tag);
2708 		return (SET_ERROR(EINVAL));
2709 	}
2710 
2711 	error = snaplist_make(dp, 0, dsl_dir_phys(dd)->dd_origin_obj,
2712 	    &ddpa->shared_snaps, tag);
2713 	if (error != 0)
2714 		goto out;
2715 
2716 	error = snaplist_make(dp, 0, ddpa->ddpa_clone->ds_object,
2717 	    &ddpa->clone_snaps, tag);
2718 	if (error != 0)
2719 		goto out;
2720 
2721 	snap = list_head(&ddpa->shared_snaps);
2722 	ASSERT3U(snap->ds->ds_object, ==, dsl_dir_phys(dd)->dd_origin_obj);
2723 	error = snaplist_make(dp, dsl_dir_phys(dd)->dd_origin_obj,
2724 	    dsl_dir_phys(snap->ds->ds_dir)->dd_head_dataset_obj,
2725 	    &ddpa->origin_snaps, tag);
2726 	if (error != 0)
2727 		goto out;
2728 
2729 	if (dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj != 0) {
2730 		error = dsl_dataset_hold_obj(dp,
2731 		    dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj,
2732 		    tag, &ddpa->origin_origin);
2733 		if (error != 0)
2734 			goto out;
2735 	}
2736 out:
2737 	if (error != 0)
2738 		promote_rele(ddpa, tag);
2739 	return (error);
2740 }
2741 
2742 static void
2743 promote_rele(dsl_dataset_promote_arg_t *ddpa, void *tag)
2744 {
2745 	snaplist_destroy(&ddpa->shared_snaps, tag);
2746 	snaplist_destroy(&ddpa->clone_snaps, tag);
2747 	snaplist_destroy(&ddpa->origin_snaps, tag);
2748 	if (ddpa->origin_origin != NULL)
2749 		dsl_dataset_rele(ddpa->origin_origin, tag);
2750 	dsl_dataset_rele(ddpa->ddpa_clone, tag);
2751 }
2752 
2753 /*
2754  * Promote a clone.
2755  *
2756  * If it fails due to a conflicting snapshot name, "conflsnap" will be filled
2757  * in with the name.  (It must be at least MAXNAMELEN bytes long.)
2758  */
2759 int
2760 dsl_dataset_promote(const char *name, char *conflsnap)
2761 {
2762 	dsl_dataset_promote_arg_t ddpa = { 0 };
2763 	uint64_t numsnaps;
2764 	int error;
2765 	objset_t *os;
2766 
2767 	/*
2768 	 * We will modify space proportional to the number of
2769 	 * snapshots.  Compute numsnaps.
2770 	 */
2771 	error = dmu_objset_hold(name, FTAG, &os);
2772 	if (error != 0)
2773 		return (error);
2774 	error = zap_count(dmu_objset_pool(os)->dp_meta_objset,
2775 	    dsl_dataset_phys(dmu_objset_ds(os))->ds_snapnames_zapobj,
2776 	    &numsnaps);
2777 	dmu_objset_rele(os, FTAG);
2778 	if (error != 0)
2779 		return (error);
2780 
2781 	ddpa.ddpa_clonename = name;
2782 	ddpa.err_ds = conflsnap;
2783 	ddpa.cr = CRED();
2784 
2785 	return (dsl_sync_task(name, dsl_dataset_promote_check,
2786 	    dsl_dataset_promote_sync, &ddpa,
2787 	    2 + numsnaps, ZFS_SPACE_CHECK_RESERVED));
2788 }
2789 
2790 int
2791 dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
2792     dsl_dataset_t *origin_head, boolean_t force, void *owner, dmu_tx_t *tx)
2793 {
2794 	/*
2795 	 * "slack" factor for received datasets with refquota set on them.
2796 	 * See the bottom of this function for details on its use.
2797 	 */
2798 	uint64_t refquota_slack = DMU_MAX_ACCESS * spa_asize_inflation;
2799 	int64_t unused_refres_delta;
2800 
2801 	/* they should both be heads */
2802 	if (clone->ds_is_snapshot ||
2803 	    origin_head->ds_is_snapshot)
2804 		return (SET_ERROR(EINVAL));
2805 
2806 	/* if we are not forcing, the branch point should be just before them */
2807 	if (!force && clone->ds_prev != origin_head->ds_prev)
2808 		return (SET_ERROR(EINVAL));
2809 
2810 	/* clone should be the clone (unless they are unrelated) */
2811 	if (clone->ds_prev != NULL &&
2812 	    clone->ds_prev != clone->ds_dir->dd_pool->dp_origin_snap &&
2813 	    origin_head->ds_dir != clone->ds_prev->ds_dir)
2814 		return (SET_ERROR(EINVAL));
2815 
2816 	/* the clone should be a child of the origin */
2817 	if (clone->ds_dir->dd_parent != origin_head->ds_dir)
2818 		return (SET_ERROR(EINVAL));
2819 
2820 	/* origin_head shouldn't be modified unless 'force' */
2821 	if (!force &&
2822 	    dsl_dataset_modified_since_snap(origin_head, origin_head->ds_prev))
2823 		return (SET_ERROR(ETXTBSY));
2824 
2825 	/* origin_head should have no long holds (e.g. is not mounted) */
2826 	if (dsl_dataset_handoff_check(origin_head, owner, tx))
2827 		return (SET_ERROR(EBUSY));
2828 
2829 	/* check amount of any unconsumed refreservation */
2830 	unused_refres_delta =
2831 	    (int64_t)MIN(origin_head->ds_reserved,
2832 	    dsl_dataset_phys(origin_head)->ds_unique_bytes) -
2833 	    (int64_t)MIN(origin_head->ds_reserved,
2834 	    dsl_dataset_phys(clone)->ds_unique_bytes);
2835 
2836 	if (unused_refres_delta > 0 &&
2837 	    unused_refres_delta >
2838 	    dsl_dir_space_available(origin_head->ds_dir, NULL, 0, TRUE))
2839 		return (SET_ERROR(ENOSPC));
2840 
2841 	/*
2842 	 * The clone can't be too much over the head's refquota.
2843 	 *
2844 	 * To ensure that the entire refquota can be used, we allow one
2845 	 * transaction to exceed the the refquota.  Therefore, this check
2846 	 * needs to also allow for the space referenced to be more than the
2847 	 * refquota.  The maximum amount of space that one transaction can use
2848 	 * on disk is DMU_MAX_ACCESS * spa_asize_inflation.  Allowing this
2849 	 * overage ensures that we are able to receive a filesystem that
2850 	 * exceeds the refquota on the source system.
2851 	 *
2852 	 * So that overage is the refquota_slack we use below.
2853 	 */
2854 	if (origin_head->ds_quota != 0 &&
2855 	    dsl_dataset_phys(clone)->ds_referenced_bytes >
2856 	    origin_head->ds_quota + refquota_slack)
2857 		return (SET_ERROR(EDQUOT));
2858 
2859 	return (0);
2860 }
2861 
2862 void
2863 dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
2864     dsl_dataset_t *origin_head, dmu_tx_t *tx)
2865 {
2866 	dsl_pool_t *dp = dmu_tx_pool(tx);
2867 	int64_t unused_refres_delta;
2868 
2869 	ASSERT(clone->ds_reserved == 0);
2870 	/*
2871 	 * NOTE: On DEBUG kernels there could be a race between this and
2872 	 * the check function if spa_asize_inflation is adjusted...
2873 	 */
2874 	ASSERT(origin_head->ds_quota == 0 ||
2875 	    dsl_dataset_phys(clone)->ds_unique_bytes <= origin_head->ds_quota +
2876 	    DMU_MAX_ACCESS * spa_asize_inflation);
2877 	ASSERT3P(clone->ds_prev, ==, origin_head->ds_prev);
2878 
2879 	/*
2880 	 * Swap per-dataset feature flags.
2881 	 */
2882 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
2883 		if (!(spa_feature_table[f].fi_flags &
2884 		    ZFEATURE_FLAG_PER_DATASET)) {
2885 			ASSERT(!clone->ds_feature_inuse[f]);
2886 			ASSERT(!origin_head->ds_feature_inuse[f]);
2887 			continue;
2888 		}
2889 
2890 		boolean_t clone_inuse = clone->ds_feature_inuse[f];
2891 		boolean_t origin_head_inuse = origin_head->ds_feature_inuse[f];
2892 
2893 		if (clone_inuse) {
2894 			dsl_dataset_deactivate_feature(clone->ds_object, f, tx);
2895 			clone->ds_feature_inuse[f] = B_FALSE;
2896 		}
2897 		if (origin_head_inuse) {
2898 			dsl_dataset_deactivate_feature(origin_head->ds_object,
2899 			    f, tx);
2900 			origin_head->ds_feature_inuse[f] = B_FALSE;
2901 		}
2902 		if (clone_inuse) {
2903 			dsl_dataset_activate_feature(origin_head->ds_object,
2904 			    f, tx);
2905 			origin_head->ds_feature_inuse[f] = B_TRUE;
2906 		}
2907 		if (origin_head_inuse) {
2908 			dsl_dataset_activate_feature(clone->ds_object, f, tx);
2909 			clone->ds_feature_inuse[f] = B_TRUE;
2910 		}
2911 	}
2912 
2913 	dmu_buf_will_dirty(clone->ds_dbuf, tx);
2914 	dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
2915 
2916 	if (clone->ds_objset != NULL) {
2917 		dmu_objset_evict(clone->ds_objset);
2918 		clone->ds_objset = NULL;
2919 	}
2920 
2921 	if (origin_head->ds_objset != NULL) {
2922 		dmu_objset_evict(origin_head->ds_objset);
2923 		origin_head->ds_objset = NULL;
2924 	}
2925 
2926 	unused_refres_delta =
2927 	    (int64_t)MIN(origin_head->ds_reserved,
2928 	    dsl_dataset_phys(origin_head)->ds_unique_bytes) -
2929 	    (int64_t)MIN(origin_head->ds_reserved,
2930 	    dsl_dataset_phys(clone)->ds_unique_bytes);
2931 
2932 	/*
2933 	 * Reset origin's unique bytes, if it exists.
2934 	 */
2935 	if (clone->ds_prev) {
2936 		dsl_dataset_t *origin = clone->ds_prev;
2937 		uint64_t comp, uncomp;
2938 
2939 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
2940 		dsl_deadlist_space_range(&clone->ds_deadlist,
2941 		    dsl_dataset_phys(origin)->ds_prev_snap_txg, UINT64_MAX,
2942 		    &dsl_dataset_phys(origin)->ds_unique_bytes, &comp, &uncomp);
2943 	}
2944 
2945 	/* swap blkptrs */
2946 	{
2947 		blkptr_t tmp;
2948 		tmp = dsl_dataset_phys(origin_head)->ds_bp;
2949 		dsl_dataset_phys(origin_head)->ds_bp =
2950 		    dsl_dataset_phys(clone)->ds_bp;
2951 		dsl_dataset_phys(clone)->ds_bp = tmp;
2952 	}
2953 
2954 	/* set dd_*_bytes */
2955 	{
2956 		int64_t dused, dcomp, duncomp;
2957 		uint64_t cdl_used, cdl_comp, cdl_uncomp;
2958 		uint64_t odl_used, odl_comp, odl_uncomp;
2959 
2960 		ASSERT3U(dsl_dir_phys(clone->ds_dir)->
2961 		    dd_used_breakdown[DD_USED_SNAP], ==, 0);
2962 
2963 		dsl_deadlist_space(&clone->ds_deadlist,
2964 		    &cdl_used, &cdl_comp, &cdl_uncomp);
2965 		dsl_deadlist_space(&origin_head->ds_deadlist,
2966 		    &odl_used, &odl_comp, &odl_uncomp);
2967 
2968 		dused = dsl_dataset_phys(clone)->ds_referenced_bytes +
2969 		    cdl_used -
2970 		    (dsl_dataset_phys(origin_head)->ds_referenced_bytes +
2971 		    odl_used);
2972 		dcomp = dsl_dataset_phys(clone)->ds_compressed_bytes +
2973 		    cdl_comp -
2974 		    (dsl_dataset_phys(origin_head)->ds_compressed_bytes +
2975 		    odl_comp);
2976 		duncomp = dsl_dataset_phys(clone)->ds_uncompressed_bytes +
2977 		    cdl_uncomp -
2978 		    (dsl_dataset_phys(origin_head)->ds_uncompressed_bytes +
2979 		    odl_uncomp);
2980 
2981 		dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_HEAD,
2982 		    dused, dcomp, duncomp, tx);
2983 		dsl_dir_diduse_space(clone->ds_dir, DD_USED_HEAD,
2984 		    -dused, -dcomp, -duncomp, tx);
2985 
2986 		/*
2987 		 * The difference in the space used by snapshots is the
2988 		 * difference in snapshot space due to the head's
2989 		 * deadlist (since that's the only thing that's
2990 		 * changing that affects the snapused).
2991 		 */
2992 		dsl_deadlist_space_range(&clone->ds_deadlist,
2993 		    origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2994 		    &cdl_used, &cdl_comp, &cdl_uncomp);
2995 		dsl_deadlist_space_range(&origin_head->ds_deadlist,
2996 		    origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
2997 		    &odl_used, &odl_comp, &odl_uncomp);
2998 		dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
2999 		    DD_USED_HEAD, DD_USED_SNAP, tx);
3000 	}
3001 
3002 	/* swap ds_*_bytes */
3003 	SWITCH64(dsl_dataset_phys(origin_head)->ds_referenced_bytes,
3004 	    dsl_dataset_phys(clone)->ds_referenced_bytes);
3005 	SWITCH64(dsl_dataset_phys(origin_head)->ds_compressed_bytes,
3006 	    dsl_dataset_phys(clone)->ds_compressed_bytes);
3007 	SWITCH64(dsl_dataset_phys(origin_head)->ds_uncompressed_bytes,
3008 	    dsl_dataset_phys(clone)->ds_uncompressed_bytes);
3009 	SWITCH64(dsl_dataset_phys(origin_head)->ds_unique_bytes,
3010 	    dsl_dataset_phys(clone)->ds_unique_bytes);
3011 
3012 	/* apply any parent delta for change in unconsumed refreservation */
3013 	dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_REFRSRV,
3014 	    unused_refres_delta, 0, 0, tx);
3015 
3016 	/*
3017 	 * Swap deadlists.
3018 	 */
3019 	dsl_deadlist_close(&clone->ds_deadlist);
3020 	dsl_deadlist_close(&origin_head->ds_deadlist);
3021 	SWITCH64(dsl_dataset_phys(origin_head)->ds_deadlist_obj,
3022 	    dsl_dataset_phys(clone)->ds_deadlist_obj);
3023 	dsl_deadlist_open(&clone->ds_deadlist, dp->dp_meta_objset,
3024 	    dsl_dataset_phys(clone)->ds_deadlist_obj);
3025 	dsl_deadlist_open(&origin_head->ds_deadlist, dp->dp_meta_objset,
3026 	    dsl_dataset_phys(origin_head)->ds_deadlist_obj);
3027 
3028 	dsl_scan_ds_clone_swapped(origin_head, clone, tx);
3029 
3030 	spa_history_log_internal_ds(clone, "clone swap", tx,
3031 	    "parent=%s", origin_head->ds_dir->dd_myname);
3032 }
3033 
3034 /*
3035  * Given a pool name and a dataset object number in that pool,
3036  * return the name of that dataset.
3037  */
3038 int
3039 dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf)
3040 {
3041 	dsl_pool_t *dp;
3042 	dsl_dataset_t *ds;
3043 	int error;
3044 
3045 	error = dsl_pool_hold(pname, FTAG, &dp);
3046 	if (error != 0)
3047 		return (error);
3048 
3049 	error = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
3050 	if (error == 0) {
3051 		dsl_dataset_name(ds, buf);
3052 		dsl_dataset_rele(ds, FTAG);
3053 	}
3054 	dsl_pool_rele(dp, FTAG);
3055 
3056 	return (error);
3057 }
3058 
3059 int
3060 dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota,
3061     uint64_t asize, uint64_t inflight, uint64_t *used, uint64_t *ref_rsrv)
3062 {
3063 	int error = 0;
3064 
3065 	ASSERT3S(asize, >, 0);
3066 
3067 	/*
3068 	 * *ref_rsrv is the portion of asize that will come from any
3069 	 * unconsumed refreservation space.
3070 	 */
3071 	*ref_rsrv = 0;
3072 
3073 	mutex_enter(&ds->ds_lock);
3074 	/*
3075 	 * Make a space adjustment for reserved bytes.
3076 	 */
3077 	if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes) {
3078 		ASSERT3U(*used, >=,
3079 		    ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
3080 		*used -=
3081 		    (ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
3082 		*ref_rsrv =
3083 		    asize - MIN(asize, parent_delta(ds, asize + inflight));
3084 	}
3085 
3086 	if (!check_quota || ds->ds_quota == 0) {
3087 		mutex_exit(&ds->ds_lock);
3088 		return (0);
3089 	}
3090 	/*
3091 	 * If they are requesting more space, and our current estimate
3092 	 * is over quota, they get to try again unless the actual
3093 	 * on-disk is over quota and there are no pending changes (which
3094 	 * may free up space for us).
3095 	 */
3096 	if (dsl_dataset_phys(ds)->ds_referenced_bytes + inflight >=
3097 	    ds->ds_quota) {
3098 		if (inflight > 0 ||
3099 		    dsl_dataset_phys(ds)->ds_referenced_bytes < ds->ds_quota)
3100 			error = SET_ERROR(ERESTART);
3101 		else
3102 			error = SET_ERROR(EDQUOT);
3103 	}
3104 	mutex_exit(&ds->ds_lock);
3105 
3106 	return (error);
3107 }
3108 
3109 typedef struct dsl_dataset_set_qr_arg {
3110 	const char *ddsqra_name;
3111 	zprop_source_t ddsqra_source;
3112 	uint64_t ddsqra_value;
3113 } dsl_dataset_set_qr_arg_t;
3114 
3115 
3116 /* ARGSUSED */
3117 static int
3118 dsl_dataset_set_refquota_check(void *arg, dmu_tx_t *tx)
3119 {
3120 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3121 	dsl_pool_t *dp = dmu_tx_pool(tx);
3122 	dsl_dataset_t *ds;
3123 	int error;
3124 	uint64_t newval;
3125 
3126 	if (spa_version(dp->dp_spa) < SPA_VERSION_REFQUOTA)
3127 		return (SET_ERROR(ENOTSUP));
3128 
3129 	error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
3130 	if (error != 0)
3131 		return (error);
3132 
3133 	if (ds->ds_is_snapshot) {
3134 		dsl_dataset_rele(ds, FTAG);
3135 		return (SET_ERROR(EINVAL));
3136 	}
3137 
3138 	error = dsl_prop_predict(ds->ds_dir,
3139 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
3140 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
3141 	if (error != 0) {
3142 		dsl_dataset_rele(ds, FTAG);
3143 		return (error);
3144 	}
3145 
3146 	if (newval == 0) {
3147 		dsl_dataset_rele(ds, FTAG);
3148 		return (0);
3149 	}
3150 
3151 	if (newval < dsl_dataset_phys(ds)->ds_referenced_bytes ||
3152 	    newval < ds->ds_reserved) {
3153 		dsl_dataset_rele(ds, FTAG);
3154 		return (SET_ERROR(ENOSPC));
3155 	}
3156 
3157 	dsl_dataset_rele(ds, FTAG);
3158 	return (0);
3159 }
3160 
3161 static void
3162 dsl_dataset_set_refquota_sync(void *arg, dmu_tx_t *tx)
3163 {
3164 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3165 	dsl_pool_t *dp = dmu_tx_pool(tx);
3166 	dsl_dataset_t *ds;
3167 	uint64_t newval;
3168 
3169 	VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
3170 
3171 	dsl_prop_set_sync_impl(ds,
3172 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
3173 	    ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
3174 	    &ddsqra->ddsqra_value, tx);
3175 
3176 	VERIFY0(dsl_prop_get_int_ds(ds,
3177 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA), &newval));
3178 
3179 	if (ds->ds_quota != newval) {
3180 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
3181 		ds->ds_quota = newval;
3182 	}
3183 	dsl_dataset_rele(ds, FTAG);
3184 }
3185 
3186 int
3187 dsl_dataset_set_refquota(const char *dsname, zprop_source_t source,
3188     uint64_t refquota)
3189 {
3190 	dsl_dataset_set_qr_arg_t ddsqra;
3191 
3192 	ddsqra.ddsqra_name = dsname;
3193 	ddsqra.ddsqra_source = source;
3194 	ddsqra.ddsqra_value = refquota;
3195 
3196 	return (dsl_sync_task(dsname, dsl_dataset_set_refquota_check,
3197 	    dsl_dataset_set_refquota_sync, &ddsqra, 0, ZFS_SPACE_CHECK_NONE));
3198 }
3199 
3200 static int
3201 dsl_dataset_set_refreservation_check(void *arg, dmu_tx_t *tx)
3202 {
3203 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3204 	dsl_pool_t *dp = dmu_tx_pool(tx);
3205 	dsl_dataset_t *ds;
3206 	int error;
3207 	uint64_t newval, unique;
3208 
3209 	if (spa_version(dp->dp_spa) < SPA_VERSION_REFRESERVATION)
3210 		return (SET_ERROR(ENOTSUP));
3211 
3212 	error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
3213 	if (error != 0)
3214 		return (error);
3215 
3216 	if (ds->ds_is_snapshot) {
3217 		dsl_dataset_rele(ds, FTAG);
3218 		return (SET_ERROR(EINVAL));
3219 	}
3220 
3221 	error = dsl_prop_predict(ds->ds_dir,
3222 	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
3223 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
3224 	if (error != 0) {
3225 		dsl_dataset_rele(ds, FTAG);
3226 		return (error);
3227 	}
3228 
3229 	/*
3230 	 * If we are doing the preliminary check in open context, the
3231 	 * space estimates may be inaccurate.
3232 	 */
3233 	if (!dmu_tx_is_syncing(tx)) {
3234 		dsl_dataset_rele(ds, FTAG);
3235 		return (0);
3236 	}
3237 
3238 	mutex_enter(&ds->ds_lock);
3239 	if (!DS_UNIQUE_IS_ACCURATE(ds))
3240 		dsl_dataset_recalc_head_uniq(ds);
3241 	unique = dsl_dataset_phys(ds)->ds_unique_bytes;
3242 	mutex_exit(&ds->ds_lock);
3243 
3244 	if (MAX(unique, newval) > MAX(unique, ds->ds_reserved)) {
3245 		uint64_t delta = MAX(unique, newval) -
3246 		    MAX(unique, ds->ds_reserved);
3247 
3248 		if (delta >
3249 		    dsl_dir_space_available(ds->ds_dir, NULL, 0, B_TRUE) ||
3250 		    (ds->ds_quota > 0 && newval > ds->ds_quota)) {
3251 			dsl_dataset_rele(ds, FTAG);
3252 			return (SET_ERROR(ENOSPC));
3253 		}
3254 	}
3255 
3256 	dsl_dataset_rele(ds, FTAG);
3257 	return (0);
3258 }
3259 
3260 void
3261 dsl_dataset_set_refreservation_sync_impl(dsl_dataset_t *ds,
3262     zprop_source_t source, uint64_t value, dmu_tx_t *tx)
3263 {
3264 	uint64_t newval;
3265 	uint64_t unique;
3266 	int64_t delta;
3267 
3268 	dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
3269 	    source, sizeof (value), 1, &value, tx);
3270 
3271 	VERIFY0(dsl_prop_get_int_ds(ds,
3272 	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &newval));
3273 
3274 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
3275 	mutex_enter(&ds->ds_dir->dd_lock);
3276 	mutex_enter(&ds->ds_lock);
3277 	ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
3278 	unique = dsl_dataset_phys(ds)->ds_unique_bytes;
3279 	delta = MAX(0, (int64_t)(newval - unique)) -
3280 	    MAX(0, (int64_t)(ds->ds_reserved - unique));
3281 	ds->ds_reserved = newval;
3282 	mutex_exit(&ds->ds_lock);
3283 
3284 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx);
3285 	mutex_exit(&ds->ds_dir->dd_lock);
3286 }
3287 
3288 static void
3289 dsl_dataset_set_refreservation_sync(void *arg, dmu_tx_t *tx)
3290 {
3291 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
3292 	dsl_pool_t *dp = dmu_tx_pool(tx);
3293 	dsl_dataset_t *ds;
3294 
3295 	VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
3296 	dsl_dataset_set_refreservation_sync_impl(ds,
3297 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, tx);
3298 	dsl_dataset_rele(ds, FTAG);
3299 }
3300 
3301 int
3302 dsl_dataset_set_refreservation(const char *dsname, zprop_source_t source,
3303     uint64_t refreservation)
3304 {
3305 	dsl_dataset_set_qr_arg_t ddsqra;
3306 
3307 	ddsqra.ddsqra_name = dsname;
3308 	ddsqra.ddsqra_source = source;
3309 	ddsqra.ddsqra_value = refreservation;
3310 
3311 	return (dsl_sync_task(dsname, dsl_dataset_set_refreservation_check,
3312 	    dsl_dataset_set_refreservation_sync, &ddsqra,
3313 	    0, ZFS_SPACE_CHECK_NONE));
3314 }
3315 
3316 /*
3317  * Return (in *usedp) the amount of space written in new that is not
3318  * present in oldsnap.  New may be a snapshot or the head.  Old must be
3319  * a snapshot before new, in new's filesystem (or its origin).  If not then
3320  * fail and return EINVAL.
3321  *
3322  * The written space is calculated by considering two components:  First, we
3323  * ignore any freed space, and calculate the written as new's used space
3324  * minus old's used space.  Next, we add in the amount of space that was freed
3325  * between the two snapshots, thus reducing new's used space relative to old's.
3326  * Specifically, this is the space that was born before old->ds_creation_txg,
3327  * and freed before new (ie. on new's deadlist or a previous deadlist).
3328  *
3329  * space freed                         [---------------------]
3330  * snapshots                       ---O-------O--------O-------O------
3331  *                                         oldsnap            new
3332  */
3333 int
3334 dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
3335     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
3336 {
3337 	int err = 0;
3338 	uint64_t snapobj;
3339 	dsl_pool_t *dp = new->ds_dir->dd_pool;
3340 
3341 	ASSERT(dsl_pool_config_held(dp));
3342 
3343 	*usedp = 0;
3344 	*usedp += dsl_dataset_phys(new)->ds_referenced_bytes;
3345 	*usedp -= dsl_dataset_phys(oldsnap)->ds_referenced_bytes;
3346 
3347 	*compp = 0;
3348 	*compp += dsl_dataset_phys(new)->ds_compressed_bytes;
3349 	*compp -= dsl_dataset_phys(oldsnap)->ds_compressed_bytes;
3350 
3351 	*uncompp = 0;
3352 	*uncompp += dsl_dataset_phys(new)->ds_uncompressed_bytes;
3353 	*uncompp -= dsl_dataset_phys(oldsnap)->ds_uncompressed_bytes;
3354 
3355 	snapobj = new->ds_object;
3356 	while (snapobj != oldsnap->ds_object) {
3357 		dsl_dataset_t *snap;
3358 		uint64_t used, comp, uncomp;
3359 
3360 		if (snapobj == new->ds_object) {
3361 			snap = new;
3362 		} else {
3363 			err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
3364 			if (err != 0)
3365 				break;
3366 		}
3367 
3368 		if (dsl_dataset_phys(snap)->ds_prev_snap_txg ==
3369 		    dsl_dataset_phys(oldsnap)->ds_creation_txg) {
3370 			/*
3371 			 * The blocks in the deadlist can not be born after
3372 			 * ds_prev_snap_txg, so get the whole deadlist space,
3373 			 * which is more efficient (especially for old-format
3374 			 * deadlists).  Unfortunately the deadlist code
3375 			 * doesn't have enough information to make this
3376 			 * optimization itself.
3377 			 */
3378 			dsl_deadlist_space(&snap->ds_deadlist,
3379 			    &used, &comp, &uncomp);
3380 		} else {
3381 			dsl_deadlist_space_range(&snap->ds_deadlist,
3382 			    0, dsl_dataset_phys(oldsnap)->ds_creation_txg,
3383 			    &used, &comp, &uncomp);
3384 		}
3385 		*usedp += used;
3386 		*compp += comp;
3387 		*uncompp += uncomp;
3388 
3389 		/*
3390 		 * If we get to the beginning of the chain of snapshots
3391 		 * (ds_prev_snap_obj == 0) before oldsnap, then oldsnap
3392 		 * was not a snapshot of/before new.
3393 		 */
3394 		snapobj = dsl_dataset_phys(snap)->ds_prev_snap_obj;
3395 		if (snap != new)
3396 			dsl_dataset_rele(snap, FTAG);
3397 		if (snapobj == 0) {
3398 			err = SET_ERROR(EINVAL);
3399 			break;
3400 		}
3401 
3402 	}
3403 	return (err);
3404 }
3405 
3406 /*
3407  * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
3408  * lastsnap, and all snapshots in between are deleted.
3409  *
3410  * blocks that would be freed            [---------------------------]
3411  * snapshots                       ---O-------O--------O-------O--------O
3412  *                                        firstsnap        lastsnap
3413  *
3414  * This is the set of blocks that were born after the snap before firstsnap,
3415  * (birth > firstsnap->prev_snap_txg) and died before the snap after the
3416  * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
3417  * We calculate this by iterating over the relevant deadlists (from the snap
3418  * after lastsnap, backward to the snap after firstsnap), summing up the
3419  * space on the deadlist that was born after the snap before firstsnap.
3420  */
3421 int
3422 dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
3423     dsl_dataset_t *lastsnap,
3424     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
3425 {
3426 	int err = 0;
3427 	uint64_t snapobj;
3428 	dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
3429 
3430 	ASSERT(firstsnap->ds_is_snapshot);
3431 	ASSERT(lastsnap->ds_is_snapshot);
3432 
3433 	/*
3434 	 * Check that the snapshots are in the same dsl_dir, and firstsnap
3435 	 * is before lastsnap.
3436 	 */
3437 	if (firstsnap->ds_dir != lastsnap->ds_dir ||
3438 	    dsl_dataset_phys(firstsnap)->ds_creation_txg >
3439 	    dsl_dataset_phys(lastsnap)->ds_creation_txg)
3440 		return (SET_ERROR(EINVAL));
3441 
3442 	*usedp = *compp = *uncompp = 0;
3443 
3444 	snapobj = dsl_dataset_phys(lastsnap)->ds_next_snap_obj;
3445 	while (snapobj != firstsnap->ds_object) {
3446 		dsl_dataset_t *ds;
3447 		uint64_t used, comp, uncomp;
3448 
3449 		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
3450 		if (err != 0)
3451 			break;
3452 
3453 		dsl_deadlist_space_range(&ds->ds_deadlist,
3454 		    dsl_dataset_phys(firstsnap)->ds_prev_snap_txg, UINT64_MAX,
3455 		    &used, &comp, &uncomp);
3456 		*usedp += used;
3457 		*compp += comp;
3458 		*uncompp += uncomp;
3459 
3460 		snapobj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
3461 		ASSERT3U(snapobj, !=, 0);
3462 		dsl_dataset_rele(ds, FTAG);
3463 	}
3464 	return (err);
3465 }
3466 
3467 /*
3468  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
3469  * For example, they could both be snapshots of the same filesystem, and
3470  * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
3471  * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
3472  * filesystem.  Or 'earlier' could be the origin's origin.
3473  *
3474  * If non-zero, earlier_txg is used instead of earlier's ds_creation_txg.
3475  */
3476 boolean_t
3477 dsl_dataset_is_before(dsl_dataset_t *later, dsl_dataset_t *earlier,
3478     uint64_t earlier_txg)
3479 {
3480 	dsl_pool_t *dp = later->ds_dir->dd_pool;
3481 	int error;
3482 	boolean_t ret;
3483 
3484 	ASSERT(dsl_pool_config_held(dp));
3485 	ASSERT(earlier->ds_is_snapshot || earlier_txg != 0);
3486 
3487 	if (earlier_txg == 0)
3488 		earlier_txg = dsl_dataset_phys(earlier)->ds_creation_txg;
3489 
3490 	if (later->ds_is_snapshot &&
3491 	    earlier_txg >= dsl_dataset_phys(later)->ds_creation_txg)
3492 		return (B_FALSE);
3493 
3494 	if (later->ds_dir == earlier->ds_dir)
3495 		return (B_TRUE);
3496 	if (!dsl_dir_is_clone(later->ds_dir))
3497 		return (B_FALSE);
3498 
3499 	if (dsl_dir_phys(later->ds_dir)->dd_origin_obj == earlier->ds_object)
3500 		return (B_TRUE);
3501 	dsl_dataset_t *origin;
3502 	error = dsl_dataset_hold_obj(dp,
3503 	    dsl_dir_phys(later->ds_dir)->dd_origin_obj, FTAG, &origin);
3504 	if (error != 0)
3505 		return (B_FALSE);
3506 	ret = dsl_dataset_is_before(origin, earlier, earlier_txg);
3507 	dsl_dataset_rele(origin, FTAG);
3508 	return (ret);
3509 }
3510 
3511 void
3512 dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx)
3513 {
3514 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
3515 	dmu_object_zapify(mos, ds->ds_object, DMU_OT_DSL_DATASET, tx);
3516 }
3517 
3518 boolean_t
3519 dsl_dataset_is_zapified(dsl_dataset_t *ds)
3520 {
3521 	dmu_object_info_t doi;
3522 
3523 	dmu_object_info_from_db(ds->ds_dbuf, &doi);
3524 	return (doi.doi_type == DMU_OTN_ZAP_METADATA);
3525 }
3526 
3527 boolean_t
3528 dsl_dataset_has_resume_receive_state(dsl_dataset_t *ds)
3529 {
3530 	return (dsl_dataset_is_zapified(ds) &&
3531 	    zap_contains(ds->ds_dir->dd_pool->dp_meta_objset,
3532 	    ds->ds_object, DS_FIELD_RESUME_TOGUID) == 0);
3533 }
3534