xref: /freebsd/sys/contrib/openzfs/module/zfs/dsl_dataset.c (revision 744bfb213144c63cbaf38d91a1c4f7aebb9b9fbc)
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 https://opensource.org/licenses/CDDL-1.0.
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 /*
23  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Copyright (c) 2011, 2020 by Delphix. All rights reserved.
25  * Copyright (c) 2014, Joyent, Inc. All rights reserved.
26  * Copyright (c) 2014 RackTop Systems.
27  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
28  * Copyright (c) 2016 Actifio, Inc. All rights reserved.
29  * Copyright 2016, OmniTI Computer Consulting, Inc. All rights reserved.
30  * Copyright 2017 Nexenta Systems, Inc.
31  * Copyright (c) 2019, Klara Inc.
32  * Copyright (c) 2019, Allan Jude
33  * Copyright (c) 2020 The FreeBSD Foundation [1]
34  *
35  * [1] Portions of this software were developed by Allan Jude
36  *     under sponsorship from the FreeBSD Foundation.
37  */
38 
39 #include <sys/dmu_objset.h>
40 #include <sys/dsl_dataset.h>
41 #include <sys/dsl_dir.h>
42 #include <sys/dsl_prop.h>
43 #include <sys/dsl_synctask.h>
44 #include <sys/dmu_traverse.h>
45 #include <sys/dmu_impl.h>
46 #include <sys/dmu_tx.h>
47 #include <sys/arc.h>
48 #include <sys/zio.h>
49 #include <sys/zap.h>
50 #include <sys/zfeature.h>
51 #include <sys/unique.h>
52 #include <sys/zfs_context.h>
53 #include <sys/zfs_ioctl.h>
54 #include <sys/spa.h>
55 #include <sys/spa_impl.h>
56 #include <sys/vdev.h>
57 #include <sys/zfs_znode.h>
58 #include <sys/zfs_onexit.h>
59 #include <sys/zvol.h>
60 #include <sys/dsl_scan.h>
61 #include <sys/dsl_deadlist.h>
62 #include <sys/dsl_destroy.h>
63 #include <sys/dsl_userhold.h>
64 #include <sys/dsl_bookmark.h>
65 #include <sys/policy.h>
66 #include <sys/dmu_send.h>
67 #include <sys/dmu_recv.h>
68 #include <sys/zio_compress.h>
69 #include <zfs_fletcher.h>
70 #include <sys/zio_checksum.h>
71 
72 /*
73  * The SPA supports block sizes up to 16MB.  However, very large blocks
74  * can have an impact on i/o latency (e.g. tying up a spinning disk for
75  * ~300ms), and also potentially on the memory allocator.  Therefore,
76  * we did not allow the recordsize to be set larger than zfs_max_recordsize
77  * (former default: 1MB).  Larger blocks could be created by changing this
78  * tunable, and pools with larger blocks could always be imported and used,
79  * regardless of this setting.
80  *
81  * We do, however, still limit it by default to 1M on x86_32, because Linux's
82  * 3/1 memory split doesn't leave much room for 16M chunks.
83  */
84 #ifdef _ILP32
85 uint_t zfs_max_recordsize =  1 * 1024 * 1024;
86 #else
87 uint_t zfs_max_recordsize = 16 * 1024 * 1024;
88 #endif
89 static int zfs_allow_redacted_dataset_mount = 0;
90 
91 int zfs_snapshot_history_enabled = 1;
92 
93 #define	SWITCH64(x, y) \
94 	{ \
95 		uint64_t __tmp = (x); \
96 		(x) = (y); \
97 		(y) = __tmp; \
98 	}
99 
100 #define	DS_REF_MAX	(1ULL << 62)
101 
102 static void dsl_dataset_set_remap_deadlist_object(dsl_dataset_t *ds,
103     uint64_t obj, dmu_tx_t *tx);
104 static void dsl_dataset_unset_remap_deadlist_object(dsl_dataset_t *ds,
105     dmu_tx_t *tx);
106 
107 static void unload_zfeature(dsl_dataset_t *ds, spa_feature_t f);
108 
109 extern uint_t spa_asize_inflation;
110 
111 static zil_header_t zero_zil;
112 
113 /*
114  * Figure out how much of this delta should be propagated to the dsl_dir
115  * layer.  If there's a refreservation, that space has already been
116  * partially accounted for in our ancestors.
117  */
118 static int64_t
119 parent_delta(dsl_dataset_t *ds, int64_t delta)
120 {
121 	dsl_dataset_phys_t *ds_phys;
122 	uint64_t old_bytes, new_bytes;
123 
124 	if (ds->ds_reserved == 0)
125 		return (delta);
126 
127 	ds_phys = dsl_dataset_phys(ds);
128 	old_bytes = MAX(ds_phys->ds_unique_bytes, ds->ds_reserved);
129 	new_bytes = MAX(ds_phys->ds_unique_bytes + delta, ds->ds_reserved);
130 
131 	ASSERT3U(ABS((int64_t)(new_bytes - old_bytes)), <=, ABS(delta));
132 	return (new_bytes - old_bytes);
133 }
134 
135 void
136 dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
137 {
138 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
139 	int used = bp_get_dsize_sync(spa, bp);
140 	int compressed = BP_GET_PSIZE(bp);
141 	int uncompressed = BP_GET_UCSIZE(bp);
142 	int64_t delta;
143 	spa_feature_t f;
144 
145 	dprintf_bp(bp, "ds=%p", ds);
146 
147 	ASSERT(dmu_tx_is_syncing(tx));
148 	/* It could have been compressed away to nothing */
149 	if (BP_IS_HOLE(bp) || BP_IS_REDACTED(bp))
150 		return;
151 	ASSERT(BP_GET_TYPE(bp) != DMU_OT_NONE);
152 	ASSERT(DMU_OT_IS_VALID(BP_GET_TYPE(bp)));
153 	if (ds == NULL) {
154 		dsl_pool_mos_diduse_space(tx->tx_pool,
155 		    used, compressed, uncompressed);
156 		return;
157 	}
158 
159 	ASSERT3U(bp->blk_birth, >, dsl_dataset_phys(ds)->ds_prev_snap_txg);
160 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
161 	mutex_enter(&ds->ds_lock);
162 	delta = parent_delta(ds, used);
163 	dsl_dataset_phys(ds)->ds_referenced_bytes += used;
164 	dsl_dataset_phys(ds)->ds_compressed_bytes += compressed;
165 	dsl_dataset_phys(ds)->ds_uncompressed_bytes += uncompressed;
166 	dsl_dataset_phys(ds)->ds_unique_bytes += used;
167 
168 	if (BP_GET_LSIZE(bp) > SPA_OLD_MAXBLOCKSIZE) {
169 		ds->ds_feature_activation[SPA_FEATURE_LARGE_BLOCKS] =
170 		    (void *)B_TRUE;
171 	}
172 
173 
174 	f = zio_checksum_to_feature(BP_GET_CHECKSUM(bp));
175 	if (f != SPA_FEATURE_NONE) {
176 		ASSERT3S(spa_feature_table[f].fi_type, ==,
177 		    ZFEATURE_TYPE_BOOLEAN);
178 		ds->ds_feature_activation[f] = (void *)B_TRUE;
179 	}
180 
181 	f = zio_compress_to_feature(BP_GET_COMPRESS(bp));
182 	if (f != SPA_FEATURE_NONE) {
183 		ASSERT3S(spa_feature_table[f].fi_type, ==,
184 		    ZFEATURE_TYPE_BOOLEAN);
185 		ds->ds_feature_activation[f] = (void *)B_TRUE;
186 	}
187 
188 	/*
189 	 * Track block for livelist, but ignore embedded blocks because
190 	 * they do not need to be freed.
191 	 */
192 	if (dsl_deadlist_is_open(&ds->ds_dir->dd_livelist) &&
193 	    bp->blk_birth > ds->ds_dir->dd_origin_txg &&
194 	    !(BP_IS_EMBEDDED(bp))) {
195 		ASSERT(dsl_dir_is_clone(ds->ds_dir));
196 		ASSERT(spa_feature_is_enabled(spa,
197 		    SPA_FEATURE_LIVELIST));
198 		bplist_append(&ds->ds_dir->dd_pending_allocs, bp);
199 	}
200 
201 	mutex_exit(&ds->ds_lock);
202 	dsl_dir_diduse_transfer_space(ds->ds_dir, delta,
203 	    compressed, uncompressed, used,
204 	    DD_USED_REFRSRV, DD_USED_HEAD, tx);
205 }
206 
207 /*
208  * Called when the specified segment has been remapped, and is thus no
209  * longer referenced in the head dataset.  The vdev must be indirect.
210  *
211  * If the segment is referenced by a snapshot, put it on the remap deadlist.
212  * Otherwise, add this segment to the obsolete spacemap.
213  */
214 void
215 dsl_dataset_block_remapped(dsl_dataset_t *ds, uint64_t vdev, uint64_t offset,
216     uint64_t size, uint64_t birth, dmu_tx_t *tx)
217 {
218 	spa_t *spa = ds->ds_dir->dd_pool->dp_spa;
219 
220 	ASSERT(dmu_tx_is_syncing(tx));
221 	ASSERT(birth <= tx->tx_txg);
222 	ASSERT(!ds->ds_is_snapshot);
223 
224 	if (birth > dsl_dataset_phys(ds)->ds_prev_snap_txg) {
225 		spa_vdev_indirect_mark_obsolete(spa, vdev, offset, size, tx);
226 	} else {
227 		blkptr_t fakebp;
228 		dva_t *dva = &fakebp.blk_dva[0];
229 
230 		ASSERT(ds != NULL);
231 
232 		mutex_enter(&ds->ds_remap_deadlist_lock);
233 		if (!dsl_dataset_remap_deadlist_exists(ds)) {
234 			dsl_dataset_create_remap_deadlist(ds, tx);
235 		}
236 		mutex_exit(&ds->ds_remap_deadlist_lock);
237 
238 		BP_ZERO(&fakebp);
239 		fakebp.blk_birth = birth;
240 		DVA_SET_VDEV(dva, vdev);
241 		DVA_SET_OFFSET(dva, offset);
242 		DVA_SET_ASIZE(dva, size);
243 		dsl_deadlist_insert(&ds->ds_remap_deadlist, &fakebp, B_FALSE,
244 		    tx);
245 	}
246 }
247 
248 int
249 dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
250     boolean_t async)
251 {
252 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
253 
254 	int used = bp_get_dsize_sync(spa, bp);
255 	int compressed = BP_GET_PSIZE(bp);
256 	int uncompressed = BP_GET_UCSIZE(bp);
257 
258 	if (BP_IS_HOLE(bp) || BP_IS_REDACTED(bp))
259 		return (0);
260 
261 	ASSERT(dmu_tx_is_syncing(tx));
262 	ASSERT(bp->blk_birth <= tx->tx_txg);
263 
264 	if (ds == NULL) {
265 		dsl_free(tx->tx_pool, tx->tx_txg, bp);
266 		dsl_pool_mos_diduse_space(tx->tx_pool,
267 		    -used, -compressed, -uncompressed);
268 		return (used);
269 	}
270 	ASSERT3P(tx->tx_pool, ==, ds->ds_dir->dd_pool);
271 
272 	ASSERT(!ds->ds_is_snapshot);
273 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
274 
275 	/*
276 	 * Track block for livelist, but ignore embedded blocks because
277 	 * they do not need to be freed.
278 	 */
279 	if (dsl_deadlist_is_open(&ds->ds_dir->dd_livelist) &&
280 	    bp->blk_birth > ds->ds_dir->dd_origin_txg &&
281 	    !(BP_IS_EMBEDDED(bp))) {
282 		ASSERT(dsl_dir_is_clone(ds->ds_dir));
283 		ASSERT(spa_feature_is_enabled(spa,
284 		    SPA_FEATURE_LIVELIST));
285 		bplist_append(&ds->ds_dir->dd_pending_frees, bp);
286 	}
287 
288 	if (bp->blk_birth > dsl_dataset_phys(ds)->ds_prev_snap_txg) {
289 		int64_t delta;
290 
291 		dprintf_bp(bp, "freeing ds=%llu", (u_longlong_t)ds->ds_object);
292 		dsl_free(tx->tx_pool, tx->tx_txg, bp);
293 
294 		mutex_enter(&ds->ds_lock);
295 		ASSERT(dsl_dataset_phys(ds)->ds_unique_bytes >= used ||
296 		    !DS_UNIQUE_IS_ACCURATE(ds));
297 		delta = parent_delta(ds, -used);
298 		dsl_dataset_phys(ds)->ds_unique_bytes -= used;
299 		mutex_exit(&ds->ds_lock);
300 		dsl_dir_diduse_transfer_space(ds->ds_dir,
301 		    delta, -compressed, -uncompressed, -used,
302 		    DD_USED_REFRSRV, DD_USED_HEAD, tx);
303 	} else {
304 		dprintf_bp(bp, "putting on dead list: %s", "");
305 		if (async) {
306 			/*
307 			 * We are here as part of zio's write done callback,
308 			 * which means we're a zio interrupt thread.  We can't
309 			 * call dsl_deadlist_insert() now because it may block
310 			 * waiting for I/O.  Instead, put bp on the deferred
311 			 * queue and let dsl_pool_sync() finish the job.
312 			 */
313 			bplist_append(&ds->ds_pending_deadlist, bp);
314 		} else {
315 			dsl_deadlist_insert(&ds->ds_deadlist, bp, B_FALSE, tx);
316 		}
317 		ASSERT3U(ds->ds_prev->ds_object, ==,
318 		    dsl_dataset_phys(ds)->ds_prev_snap_obj);
319 		ASSERT(dsl_dataset_phys(ds->ds_prev)->ds_num_children > 0);
320 		/* if (bp->blk_birth > prev prev snap txg) prev unique += bs */
321 		if (dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
322 		    ds->ds_object && bp->blk_birth >
323 		    dsl_dataset_phys(ds->ds_prev)->ds_prev_snap_txg) {
324 			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
325 			mutex_enter(&ds->ds_prev->ds_lock);
326 			dsl_dataset_phys(ds->ds_prev)->ds_unique_bytes += used;
327 			mutex_exit(&ds->ds_prev->ds_lock);
328 		}
329 		if (bp->blk_birth > ds->ds_dir->dd_origin_txg) {
330 			dsl_dir_transfer_space(ds->ds_dir, used,
331 			    DD_USED_HEAD, DD_USED_SNAP, tx);
332 		}
333 	}
334 
335 	dsl_bookmark_block_killed(ds, bp, tx);
336 
337 	mutex_enter(&ds->ds_lock);
338 	ASSERT3U(dsl_dataset_phys(ds)->ds_referenced_bytes, >=, used);
339 	dsl_dataset_phys(ds)->ds_referenced_bytes -= used;
340 	ASSERT3U(dsl_dataset_phys(ds)->ds_compressed_bytes, >=, compressed);
341 	dsl_dataset_phys(ds)->ds_compressed_bytes -= compressed;
342 	ASSERT3U(dsl_dataset_phys(ds)->ds_uncompressed_bytes, >=, uncompressed);
343 	dsl_dataset_phys(ds)->ds_uncompressed_bytes -= uncompressed;
344 	mutex_exit(&ds->ds_lock);
345 
346 	return (used);
347 }
348 
349 struct feature_type_uint64_array_arg {
350 	uint64_t length;
351 	uint64_t *array;
352 };
353 
354 static void
355 unload_zfeature(dsl_dataset_t *ds, spa_feature_t f)
356 {
357 	switch (spa_feature_table[f].fi_type) {
358 	case ZFEATURE_TYPE_BOOLEAN:
359 		break;
360 	case ZFEATURE_TYPE_UINT64_ARRAY:
361 	{
362 		struct feature_type_uint64_array_arg *ftuaa = ds->ds_feature[f];
363 		kmem_free(ftuaa->array, ftuaa->length * sizeof (uint64_t));
364 		kmem_free(ftuaa, sizeof (*ftuaa));
365 		break;
366 	}
367 	default:
368 		panic("Invalid zfeature type %d", spa_feature_table[f].fi_type);
369 	}
370 }
371 
372 static int
373 load_zfeature(objset_t *mos, dsl_dataset_t *ds, spa_feature_t f)
374 {
375 	int err = 0;
376 	switch (spa_feature_table[f].fi_type) {
377 	case ZFEATURE_TYPE_BOOLEAN:
378 		err = zap_contains(mos, ds->ds_object,
379 		    spa_feature_table[f].fi_guid);
380 		if (err == 0) {
381 			ds->ds_feature[f] = (void *)B_TRUE;
382 		} else {
383 			ASSERT3U(err, ==, ENOENT);
384 			err = 0;
385 		}
386 		break;
387 	case ZFEATURE_TYPE_UINT64_ARRAY:
388 	{
389 		uint64_t int_size, num_int;
390 		uint64_t *data;
391 		err = zap_length(mos, ds->ds_object,
392 		    spa_feature_table[f].fi_guid, &int_size, &num_int);
393 		if (err != 0) {
394 			ASSERT3U(err, ==, ENOENT);
395 			err = 0;
396 			break;
397 		}
398 		ASSERT3U(int_size, ==, sizeof (uint64_t));
399 		data = kmem_alloc(int_size * num_int, KM_SLEEP);
400 		VERIFY0(zap_lookup(mos, ds->ds_object,
401 		    spa_feature_table[f].fi_guid, int_size, num_int, data));
402 		struct feature_type_uint64_array_arg *ftuaa =
403 		    kmem_alloc(sizeof (*ftuaa), KM_SLEEP);
404 		ftuaa->length = num_int;
405 		ftuaa->array = data;
406 		ds->ds_feature[f] = ftuaa;
407 		break;
408 	}
409 	default:
410 		panic("Invalid zfeature type %d", spa_feature_table[f].fi_type);
411 	}
412 	return (err);
413 }
414 
415 /*
416  * We have to release the fsid synchronously or we risk that a subsequent
417  * mount of the same dataset will fail to unique_insert the fsid.  This
418  * failure would manifest itself as the fsid of this dataset changing
419  * between mounts which makes NFS clients quite unhappy.
420  */
421 static void
422 dsl_dataset_evict_sync(void *dbu)
423 {
424 	dsl_dataset_t *ds = dbu;
425 
426 	ASSERT(ds->ds_owner == NULL);
427 
428 	unique_remove(ds->ds_fsid_guid);
429 }
430 
431 static void
432 dsl_dataset_evict_async(void *dbu)
433 {
434 	dsl_dataset_t *ds = dbu;
435 
436 	ASSERT(ds->ds_owner == NULL);
437 
438 	ds->ds_dbuf = NULL;
439 
440 	if (ds->ds_objset != NULL)
441 		dmu_objset_evict(ds->ds_objset);
442 
443 	if (ds->ds_prev) {
444 		dsl_dataset_rele(ds->ds_prev, ds);
445 		ds->ds_prev = NULL;
446 	}
447 
448 	dsl_bookmark_fini_ds(ds);
449 
450 	bplist_destroy(&ds->ds_pending_deadlist);
451 	if (dsl_deadlist_is_open(&ds->ds_deadlist))
452 		dsl_deadlist_close(&ds->ds_deadlist);
453 	if (dsl_deadlist_is_open(&ds->ds_remap_deadlist))
454 		dsl_deadlist_close(&ds->ds_remap_deadlist);
455 	if (ds->ds_dir)
456 		dsl_dir_async_rele(ds->ds_dir, ds);
457 
458 	ASSERT(!list_link_active(&ds->ds_synced_link));
459 
460 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
461 		if (dsl_dataset_feature_is_active(ds, f))
462 			unload_zfeature(ds, f);
463 	}
464 
465 	list_destroy(&ds->ds_prop_cbs);
466 	mutex_destroy(&ds->ds_lock);
467 	mutex_destroy(&ds->ds_opening_lock);
468 	mutex_destroy(&ds->ds_sendstream_lock);
469 	mutex_destroy(&ds->ds_remap_deadlist_lock);
470 	zfs_refcount_destroy(&ds->ds_longholds);
471 	rrw_destroy(&ds->ds_bp_rwlock);
472 
473 	kmem_free(ds, sizeof (dsl_dataset_t));
474 }
475 
476 int
477 dsl_dataset_get_snapname(dsl_dataset_t *ds)
478 {
479 	dsl_dataset_phys_t *headphys;
480 	int err;
481 	dmu_buf_t *headdbuf;
482 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
483 	objset_t *mos = dp->dp_meta_objset;
484 
485 	if (ds->ds_snapname[0])
486 		return (0);
487 	if (dsl_dataset_phys(ds)->ds_next_snap_obj == 0)
488 		return (0);
489 
490 	err = dmu_bonus_hold(mos, dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj,
491 	    FTAG, &headdbuf);
492 	if (err != 0)
493 		return (err);
494 	headphys = headdbuf->db_data;
495 	err = zap_value_search(dp->dp_meta_objset,
496 	    headphys->ds_snapnames_zapobj, ds->ds_object, 0, ds->ds_snapname);
497 	if (err != 0 && zfs_recover == B_TRUE) {
498 		err = 0;
499 		(void) snprintf(ds->ds_snapname, sizeof (ds->ds_snapname),
500 		    "SNAPOBJ=%llu-ERR=%d",
501 		    (unsigned long long)ds->ds_object, err);
502 	}
503 	dmu_buf_rele(headdbuf, FTAG);
504 	return (err);
505 }
506 
507 int
508 dsl_dataset_snap_lookup(dsl_dataset_t *ds, const char *name, uint64_t *value)
509 {
510 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
511 	uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
512 	matchtype_t mt = 0;
513 	int err;
514 
515 	if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
516 		mt = MT_NORMALIZE;
517 
518 	err = zap_lookup_norm(mos, snapobj, name, 8, 1,
519 	    value, mt, NULL, 0, NULL);
520 	if (err == ENOTSUP && (mt & MT_NORMALIZE))
521 		err = zap_lookup(mos, snapobj, name, 8, 1, value);
522 	return (err);
523 }
524 
525 int
526 dsl_dataset_snap_remove(dsl_dataset_t *ds, const char *name, dmu_tx_t *tx,
527     boolean_t adj_cnt)
528 {
529 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
530 	uint64_t snapobj = dsl_dataset_phys(ds)->ds_snapnames_zapobj;
531 	matchtype_t mt = 0;
532 	int err;
533 
534 	dsl_dir_snap_cmtime_update(ds->ds_dir, tx);
535 
536 	if (dsl_dataset_phys(ds)->ds_flags & DS_FLAG_CI_DATASET)
537 		mt = MT_NORMALIZE;
538 
539 	err = zap_remove_norm(mos, snapobj, name, mt, tx);
540 	if (err == ENOTSUP && (mt & MT_NORMALIZE))
541 		err = zap_remove(mos, snapobj, name, tx);
542 
543 	if (err == 0 && adj_cnt)
544 		dsl_fs_ss_count_adjust(ds->ds_dir, -1,
545 		    DD_FIELD_SNAPSHOT_COUNT, tx);
546 
547 	return (err);
548 }
549 
550 boolean_t
551 dsl_dataset_try_add_ref(dsl_pool_t *dp, dsl_dataset_t *ds, const void *tag)
552 {
553 	dmu_buf_t *dbuf = ds->ds_dbuf;
554 	boolean_t result = B_FALSE;
555 
556 	if (dbuf != NULL && dmu_buf_try_add_ref(dbuf, dp->dp_meta_objset,
557 	    ds->ds_object, DMU_BONUS_BLKID, tag)) {
558 
559 		if (ds == dmu_buf_get_user(dbuf))
560 			result = B_TRUE;
561 		else
562 			dmu_buf_rele(dbuf, tag);
563 	}
564 
565 	return (result);
566 }
567 
568 int
569 dsl_dataset_hold_obj(dsl_pool_t *dp, uint64_t dsobj, const void *tag,
570     dsl_dataset_t **dsp)
571 {
572 	objset_t *mos = dp->dp_meta_objset;
573 	dmu_buf_t *dbuf;
574 	dsl_dataset_t *ds;
575 	int err;
576 	dmu_object_info_t doi;
577 
578 	ASSERT(dsl_pool_config_held(dp));
579 
580 	err = dmu_bonus_hold(mos, dsobj, tag, &dbuf);
581 	if (err != 0)
582 		return (err);
583 
584 	/* Make sure dsobj has the correct object type. */
585 	dmu_object_info_from_db(dbuf, &doi);
586 	if (doi.doi_bonus_type != DMU_OT_DSL_DATASET) {
587 		dmu_buf_rele(dbuf, tag);
588 		return (SET_ERROR(EINVAL));
589 	}
590 
591 	ds = dmu_buf_get_user(dbuf);
592 	if (ds == NULL) {
593 		dsl_dataset_t *winner = NULL;
594 
595 		ds = kmem_zalloc(sizeof (dsl_dataset_t), KM_SLEEP);
596 		ds->ds_dbuf = dbuf;
597 		ds->ds_object = dsobj;
598 		ds->ds_is_snapshot = dsl_dataset_phys(ds)->ds_num_children != 0;
599 		list_link_init(&ds->ds_synced_link);
600 
601 		err = dsl_dir_hold_obj(dp, dsl_dataset_phys(ds)->ds_dir_obj,
602 		    NULL, ds, &ds->ds_dir);
603 		if (err != 0) {
604 			kmem_free(ds, sizeof (dsl_dataset_t));
605 			dmu_buf_rele(dbuf, tag);
606 			return (err);
607 		}
608 
609 		mutex_init(&ds->ds_lock, NULL, MUTEX_DEFAULT, NULL);
610 		mutex_init(&ds->ds_opening_lock, NULL, MUTEX_DEFAULT, NULL);
611 		mutex_init(&ds->ds_sendstream_lock, NULL, MUTEX_DEFAULT, NULL);
612 		mutex_init(&ds->ds_remap_deadlist_lock,
613 		    NULL, MUTEX_DEFAULT, NULL);
614 		rrw_init(&ds->ds_bp_rwlock, B_FALSE);
615 		zfs_refcount_create(&ds->ds_longholds);
616 
617 		bplist_create(&ds->ds_pending_deadlist);
618 
619 		list_create(&ds->ds_sendstreams, sizeof (dmu_sendstatus_t),
620 		    offsetof(dmu_sendstatus_t, dss_link));
621 
622 		list_create(&ds->ds_prop_cbs, sizeof (dsl_prop_cb_record_t),
623 		    offsetof(dsl_prop_cb_record_t, cbr_ds_node));
624 
625 		if (doi.doi_type == DMU_OTN_ZAP_METADATA) {
626 			spa_feature_t f;
627 
628 			for (f = 0; f < SPA_FEATURES; f++) {
629 				if (!(spa_feature_table[f].fi_flags &
630 				    ZFEATURE_FLAG_PER_DATASET))
631 					continue;
632 				err = load_zfeature(mos, ds, f);
633 			}
634 		}
635 
636 		if (!ds->ds_is_snapshot) {
637 			ds->ds_snapname[0] = '\0';
638 			if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
639 				err = dsl_dataset_hold_obj(dp,
640 				    dsl_dataset_phys(ds)->ds_prev_snap_obj,
641 				    ds, &ds->ds_prev);
642 			}
643 			if (err != 0)
644 				goto after_dsl_bookmark_fini;
645 			err = dsl_bookmark_init_ds(ds);
646 		} else {
647 			if (zfs_flags & ZFS_DEBUG_SNAPNAMES)
648 				err = dsl_dataset_get_snapname(ds);
649 			if (err == 0 &&
650 			    dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
651 				err = zap_count(
652 				    ds->ds_dir->dd_pool->dp_meta_objset,
653 				    dsl_dataset_phys(ds)->ds_userrefs_obj,
654 				    &ds->ds_userrefs);
655 			}
656 		}
657 
658 		if (err == 0 && !ds->ds_is_snapshot) {
659 			err = dsl_prop_get_int_ds(ds,
660 			    zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
661 			    &ds->ds_reserved);
662 			if (err == 0) {
663 				err = dsl_prop_get_int_ds(ds,
664 				    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
665 				    &ds->ds_quota);
666 			}
667 		} else {
668 			ds->ds_reserved = ds->ds_quota = 0;
669 		}
670 
671 		if (err == 0 && ds->ds_dir->dd_crypto_obj != 0 &&
672 		    ds->ds_is_snapshot &&
673 		    zap_contains(mos, dsobj, DS_FIELD_IVSET_GUID) != 0) {
674 			dp->dp_spa->spa_errata =
675 			    ZPOOL_ERRATA_ZOL_8308_ENCRYPTION;
676 		}
677 
678 		dsl_deadlist_open(&ds->ds_deadlist,
679 		    mos, dsl_dataset_phys(ds)->ds_deadlist_obj);
680 		uint64_t remap_deadlist_obj =
681 		    dsl_dataset_get_remap_deadlist_object(ds);
682 		if (remap_deadlist_obj != 0) {
683 			dsl_deadlist_open(&ds->ds_remap_deadlist, mos,
684 			    remap_deadlist_obj);
685 		}
686 
687 		dmu_buf_init_user(&ds->ds_dbu, dsl_dataset_evict_sync,
688 		    dsl_dataset_evict_async, &ds->ds_dbuf);
689 		if (err == 0)
690 			winner = dmu_buf_set_user_ie(dbuf, &ds->ds_dbu);
691 
692 		if (err != 0 || winner != NULL) {
693 			dsl_deadlist_close(&ds->ds_deadlist);
694 			if (dsl_deadlist_is_open(&ds->ds_remap_deadlist))
695 				dsl_deadlist_close(&ds->ds_remap_deadlist);
696 			dsl_bookmark_fini_ds(ds);
697 after_dsl_bookmark_fini:
698 			if (ds->ds_prev)
699 				dsl_dataset_rele(ds->ds_prev, ds);
700 			dsl_dir_rele(ds->ds_dir, ds);
701 			for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
702 				if (dsl_dataset_feature_is_active(ds, f))
703 					unload_zfeature(ds, f);
704 			}
705 
706 			list_destroy(&ds->ds_prop_cbs);
707 			list_destroy(&ds->ds_sendstreams);
708 			bplist_destroy(&ds->ds_pending_deadlist);
709 			mutex_destroy(&ds->ds_lock);
710 			mutex_destroy(&ds->ds_opening_lock);
711 			mutex_destroy(&ds->ds_sendstream_lock);
712 			mutex_destroy(&ds->ds_remap_deadlist_lock);
713 			zfs_refcount_destroy(&ds->ds_longholds);
714 			rrw_destroy(&ds->ds_bp_rwlock);
715 			kmem_free(ds, sizeof (dsl_dataset_t));
716 			if (err != 0) {
717 				dmu_buf_rele(dbuf, tag);
718 				return (err);
719 			}
720 			ds = winner;
721 		} else {
722 			ds->ds_fsid_guid =
723 			    unique_insert(dsl_dataset_phys(ds)->ds_fsid_guid);
724 			if (ds->ds_fsid_guid !=
725 			    dsl_dataset_phys(ds)->ds_fsid_guid) {
726 				zfs_dbgmsg("ds_fsid_guid changed from "
727 				    "%llx to %llx for pool %s dataset id %llu",
728 				    (long long)
729 				    dsl_dataset_phys(ds)->ds_fsid_guid,
730 				    (long long)ds->ds_fsid_guid,
731 				    spa_name(dp->dp_spa),
732 				    (u_longlong_t)dsobj);
733 			}
734 		}
735 	}
736 
737 	ASSERT3P(ds->ds_dbuf, ==, dbuf);
738 	ASSERT3P(dsl_dataset_phys(ds), ==, dbuf->db_data);
739 	ASSERT(dsl_dataset_phys(ds)->ds_prev_snap_obj != 0 ||
740 	    spa_version(dp->dp_spa) < SPA_VERSION_ORIGIN ||
741 	    dp->dp_origin_snap == NULL || ds == dp->dp_origin_snap);
742 	*dsp = ds;
743 
744 	return (0);
745 }
746 
747 int
748 dsl_dataset_create_key_mapping(dsl_dataset_t *ds)
749 {
750 	dsl_dir_t *dd = ds->ds_dir;
751 
752 	if (dd->dd_crypto_obj == 0)
753 		return (0);
754 
755 	return (spa_keystore_create_mapping(dd->dd_pool->dp_spa,
756 	    ds, ds, &ds->ds_key_mapping));
757 }
758 
759 int
760 dsl_dataset_hold_obj_flags(dsl_pool_t *dp, uint64_t dsobj,
761     ds_hold_flags_t flags, const void *tag, dsl_dataset_t **dsp)
762 {
763 	int err;
764 
765 	err = dsl_dataset_hold_obj(dp, dsobj, tag, dsp);
766 	if (err != 0)
767 		return (err);
768 
769 	ASSERT3P(*dsp, !=, NULL);
770 
771 	if (flags & DS_HOLD_FLAG_DECRYPT) {
772 		err = dsl_dataset_create_key_mapping(*dsp);
773 		if (err != 0)
774 			dsl_dataset_rele(*dsp, tag);
775 	}
776 
777 	return (err);
778 }
779 
780 int
781 dsl_dataset_hold_flags(dsl_pool_t *dp, const char *name, ds_hold_flags_t flags,
782     const void *tag, dsl_dataset_t **dsp)
783 {
784 	dsl_dir_t *dd;
785 	const char *snapname;
786 	uint64_t obj;
787 	int err = 0;
788 	dsl_dataset_t *ds;
789 
790 	err = dsl_dir_hold(dp, name, FTAG, &dd, &snapname);
791 	if (err != 0)
792 		return (err);
793 
794 	ASSERT(dsl_pool_config_held(dp));
795 	obj = dsl_dir_phys(dd)->dd_head_dataset_obj;
796 	if (obj != 0)
797 		err = dsl_dataset_hold_obj_flags(dp, obj, flags, tag, &ds);
798 	else
799 		err = SET_ERROR(ENOENT);
800 
801 	/* we may be looking for a snapshot */
802 	if (err == 0 && snapname != NULL) {
803 		dsl_dataset_t *snap_ds;
804 
805 		if (*snapname++ != '@') {
806 			dsl_dataset_rele_flags(ds, flags, tag);
807 			dsl_dir_rele(dd, FTAG);
808 			return (SET_ERROR(ENOENT));
809 		}
810 
811 		dprintf("looking for snapshot '%s'\n", snapname);
812 		err = dsl_dataset_snap_lookup(ds, snapname, &obj);
813 		if (err == 0) {
814 			err = dsl_dataset_hold_obj_flags(dp, obj, flags, tag,
815 			    &snap_ds);
816 		}
817 		dsl_dataset_rele_flags(ds, flags, tag);
818 
819 		if (err == 0) {
820 			mutex_enter(&snap_ds->ds_lock);
821 			if (snap_ds->ds_snapname[0] == 0)
822 				(void) strlcpy(snap_ds->ds_snapname, snapname,
823 				    sizeof (snap_ds->ds_snapname));
824 			mutex_exit(&snap_ds->ds_lock);
825 			ds = snap_ds;
826 		}
827 	}
828 	if (err == 0)
829 		*dsp = ds;
830 	dsl_dir_rele(dd, FTAG);
831 	return (err);
832 }
833 
834 int
835 dsl_dataset_hold(dsl_pool_t *dp, const char *name, const void *tag,
836     dsl_dataset_t **dsp)
837 {
838 	return (dsl_dataset_hold_flags(dp, name, 0, tag, dsp));
839 }
840 
841 static int
842 dsl_dataset_own_obj_impl(dsl_pool_t *dp, uint64_t dsobj, ds_hold_flags_t flags,
843     const void *tag, boolean_t override, dsl_dataset_t **dsp)
844 {
845 	int err = dsl_dataset_hold_obj_flags(dp, dsobj, flags, tag, dsp);
846 	if (err != 0)
847 		return (err);
848 	if (!dsl_dataset_tryown(*dsp, tag, override)) {
849 		dsl_dataset_rele_flags(*dsp, flags, tag);
850 		*dsp = NULL;
851 		return (SET_ERROR(EBUSY));
852 	}
853 	return (0);
854 }
855 
856 
857 int
858 dsl_dataset_own_obj(dsl_pool_t *dp, uint64_t dsobj, ds_hold_flags_t flags,
859     const void *tag, dsl_dataset_t **dsp)
860 {
861 	return (dsl_dataset_own_obj_impl(dp, dsobj, flags, tag, B_FALSE, dsp));
862 }
863 
864 int
865 dsl_dataset_own_obj_force(dsl_pool_t *dp, uint64_t dsobj,
866     ds_hold_flags_t flags, const void *tag, dsl_dataset_t **dsp)
867 {
868 	return (dsl_dataset_own_obj_impl(dp, dsobj, flags, tag, B_TRUE, dsp));
869 }
870 
871 static int
872 dsl_dataset_own_impl(dsl_pool_t *dp, const char *name, ds_hold_flags_t flags,
873     const void *tag, boolean_t override, dsl_dataset_t **dsp)
874 {
875 	int err = dsl_dataset_hold_flags(dp, name, flags, tag, dsp);
876 	if (err != 0)
877 		return (err);
878 	if (!dsl_dataset_tryown(*dsp, tag, override)) {
879 		dsl_dataset_rele_flags(*dsp, flags, tag);
880 		return (SET_ERROR(EBUSY));
881 	}
882 	return (0);
883 }
884 
885 int
886 dsl_dataset_own_force(dsl_pool_t *dp, const char *name, ds_hold_flags_t flags,
887     const void *tag, dsl_dataset_t **dsp)
888 {
889 	return (dsl_dataset_own_impl(dp, name, flags, tag, B_TRUE, dsp));
890 }
891 
892 int
893 dsl_dataset_own(dsl_pool_t *dp, const char *name, ds_hold_flags_t flags,
894     const void *tag, dsl_dataset_t **dsp)
895 {
896 	return (dsl_dataset_own_impl(dp, name, flags, tag, B_FALSE, dsp));
897 }
898 
899 /*
900  * See the comment above dsl_pool_hold() for details.  In summary, a long
901  * hold is used to prevent destruction of a dataset while the pool hold
902  * is dropped, allowing other concurrent operations (e.g. spa_sync()).
903  *
904  * The dataset and pool must be held when this function is called.  After it
905  * is called, the pool hold may be released while the dataset is still held
906  * and accessed.
907  */
908 void
909 dsl_dataset_long_hold(dsl_dataset_t *ds, const void *tag)
910 {
911 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
912 	(void) zfs_refcount_add(&ds->ds_longholds, tag);
913 }
914 
915 void
916 dsl_dataset_long_rele(dsl_dataset_t *ds, const void *tag)
917 {
918 	(void) zfs_refcount_remove(&ds->ds_longholds, tag);
919 }
920 
921 /* Return B_TRUE if there are any long holds on this dataset. */
922 boolean_t
923 dsl_dataset_long_held(dsl_dataset_t *ds)
924 {
925 	return (!zfs_refcount_is_zero(&ds->ds_longholds));
926 }
927 
928 void
929 dsl_dataset_name(dsl_dataset_t *ds, char *name)
930 {
931 	if (ds == NULL) {
932 		(void) strlcpy(name, "mos", ZFS_MAX_DATASET_NAME_LEN);
933 	} else {
934 		dsl_dir_name(ds->ds_dir, name);
935 		VERIFY0(dsl_dataset_get_snapname(ds));
936 		if (ds->ds_snapname[0]) {
937 			VERIFY3U(strlcat(name, "@", ZFS_MAX_DATASET_NAME_LEN),
938 			    <, ZFS_MAX_DATASET_NAME_LEN);
939 			/*
940 			 * We use a "recursive" mutex so that we
941 			 * can call dprintf_ds() with ds_lock held.
942 			 */
943 			if (!MUTEX_HELD(&ds->ds_lock)) {
944 				mutex_enter(&ds->ds_lock);
945 				VERIFY3U(strlcat(name, ds->ds_snapname,
946 				    ZFS_MAX_DATASET_NAME_LEN), <,
947 				    ZFS_MAX_DATASET_NAME_LEN);
948 				mutex_exit(&ds->ds_lock);
949 			} else {
950 				VERIFY3U(strlcat(name, ds->ds_snapname,
951 				    ZFS_MAX_DATASET_NAME_LEN), <,
952 				    ZFS_MAX_DATASET_NAME_LEN);
953 			}
954 		}
955 	}
956 }
957 
958 int
959 dsl_dataset_namelen(dsl_dataset_t *ds)
960 {
961 	VERIFY0(dsl_dataset_get_snapname(ds));
962 	mutex_enter(&ds->ds_lock);
963 	int len = strlen(ds->ds_snapname);
964 	mutex_exit(&ds->ds_lock);
965 	/* add '@' if ds is a snap */
966 	if (len > 0)
967 		len++;
968 	len += dsl_dir_namelen(ds->ds_dir);
969 	return (len);
970 }
971 
972 void
973 dsl_dataset_rele(dsl_dataset_t *ds, const void *tag)
974 {
975 	dmu_buf_rele(ds->ds_dbuf, tag);
976 }
977 
978 void
979 dsl_dataset_remove_key_mapping(dsl_dataset_t *ds)
980 {
981 	dsl_dir_t *dd = ds->ds_dir;
982 
983 	if (dd == NULL || dd->dd_crypto_obj == 0)
984 		return;
985 
986 	(void) spa_keystore_remove_mapping(dd->dd_pool->dp_spa,
987 	    ds->ds_object, ds);
988 }
989 
990 void
991 dsl_dataset_rele_flags(dsl_dataset_t *ds, ds_hold_flags_t flags,
992     const void *tag)
993 {
994 	if (flags & DS_HOLD_FLAG_DECRYPT)
995 		dsl_dataset_remove_key_mapping(ds);
996 
997 	dsl_dataset_rele(ds, tag);
998 }
999 
1000 void
1001 dsl_dataset_disown(dsl_dataset_t *ds, ds_hold_flags_t flags, const void *tag)
1002 {
1003 	ASSERT3P(ds->ds_owner, ==, tag);
1004 	ASSERT(ds->ds_dbuf != NULL);
1005 
1006 	mutex_enter(&ds->ds_lock);
1007 	ds->ds_owner = NULL;
1008 	mutex_exit(&ds->ds_lock);
1009 	dsl_dataset_long_rele(ds, tag);
1010 	dsl_dataset_rele_flags(ds, flags, tag);
1011 }
1012 
1013 boolean_t
1014 dsl_dataset_tryown(dsl_dataset_t *ds, const void *tag, boolean_t override)
1015 {
1016 	boolean_t gotit = FALSE;
1017 
1018 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
1019 	mutex_enter(&ds->ds_lock);
1020 	if (ds->ds_owner == NULL && (override || !(DS_IS_INCONSISTENT(ds) ||
1021 	    (dsl_dataset_feature_is_active(ds,
1022 	    SPA_FEATURE_REDACTED_DATASETS) &&
1023 	    !zfs_allow_redacted_dataset_mount)))) {
1024 		ds->ds_owner = tag;
1025 		dsl_dataset_long_hold(ds, tag);
1026 		gotit = TRUE;
1027 	}
1028 	mutex_exit(&ds->ds_lock);
1029 	return (gotit);
1030 }
1031 
1032 boolean_t
1033 dsl_dataset_has_owner(dsl_dataset_t *ds)
1034 {
1035 	boolean_t rv;
1036 	mutex_enter(&ds->ds_lock);
1037 	rv = (ds->ds_owner != NULL);
1038 	mutex_exit(&ds->ds_lock);
1039 	return (rv);
1040 }
1041 
1042 static boolean_t
1043 zfeature_active(spa_feature_t f, void *arg)
1044 {
1045 	switch (spa_feature_table[f].fi_type) {
1046 	case ZFEATURE_TYPE_BOOLEAN: {
1047 		boolean_t val = (boolean_t)(uintptr_t)arg;
1048 		ASSERT(val == B_FALSE || val == B_TRUE);
1049 		return (val);
1050 	}
1051 	case ZFEATURE_TYPE_UINT64_ARRAY:
1052 		/*
1053 		 * In this case, arg is a uint64_t array.  The feature is active
1054 		 * if the array is non-null.
1055 		 */
1056 		return (arg != NULL);
1057 	default:
1058 		panic("Invalid zfeature type %d", spa_feature_table[f].fi_type);
1059 		return (B_FALSE);
1060 	}
1061 }
1062 
1063 boolean_t
1064 dsl_dataset_feature_is_active(dsl_dataset_t *ds, spa_feature_t f)
1065 {
1066 	return (zfeature_active(f, ds->ds_feature[f]));
1067 }
1068 
1069 /*
1070  * The buffers passed out by this function are references to internal buffers;
1071  * they should not be freed by callers of this function, and they should not be
1072  * used after the dataset has been released.
1073  */
1074 boolean_t
1075 dsl_dataset_get_uint64_array_feature(dsl_dataset_t *ds, spa_feature_t f,
1076     uint64_t *outlength, uint64_t **outp)
1077 {
1078 	VERIFY(spa_feature_table[f].fi_type & ZFEATURE_TYPE_UINT64_ARRAY);
1079 	if (!dsl_dataset_feature_is_active(ds, f)) {
1080 		return (B_FALSE);
1081 	}
1082 	struct feature_type_uint64_array_arg *ftuaa = ds->ds_feature[f];
1083 	*outp = ftuaa->array;
1084 	*outlength = ftuaa->length;
1085 	return (B_TRUE);
1086 }
1087 
1088 void
1089 dsl_dataset_activate_feature(uint64_t dsobj, spa_feature_t f, void *arg,
1090     dmu_tx_t *tx)
1091 {
1092 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
1093 	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
1094 	uint64_t zero = 0;
1095 
1096 	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
1097 
1098 	spa_feature_incr(spa, f, tx);
1099 	dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
1100 
1101 	switch (spa_feature_table[f].fi_type) {
1102 	case ZFEATURE_TYPE_BOOLEAN:
1103 		ASSERT3S((boolean_t)(uintptr_t)arg, ==, B_TRUE);
1104 		VERIFY0(zap_add(mos, dsobj, spa_feature_table[f].fi_guid,
1105 		    sizeof (zero), 1, &zero, tx));
1106 		break;
1107 	case ZFEATURE_TYPE_UINT64_ARRAY:
1108 	{
1109 		struct feature_type_uint64_array_arg *ftuaa = arg;
1110 		VERIFY0(zap_add(mos, dsobj, spa_feature_table[f].fi_guid,
1111 		    sizeof (uint64_t), ftuaa->length, ftuaa->array, tx));
1112 		break;
1113 	}
1114 	default:
1115 		panic("Invalid zfeature type %d", spa_feature_table[f].fi_type);
1116 	}
1117 }
1118 
1119 static void
1120 dsl_dataset_deactivate_feature_impl(dsl_dataset_t *ds, spa_feature_t f,
1121     dmu_tx_t *tx)
1122 {
1123 	spa_t *spa = dmu_tx_pool(tx)->dp_spa;
1124 	objset_t *mos = dmu_tx_pool(tx)->dp_meta_objset;
1125 	uint64_t dsobj = ds->ds_object;
1126 
1127 	VERIFY(spa_feature_table[f].fi_flags & ZFEATURE_FLAG_PER_DATASET);
1128 
1129 	VERIFY0(zap_remove(mos, dsobj, spa_feature_table[f].fi_guid, tx));
1130 	spa_feature_decr(spa, f, tx);
1131 	ds->ds_feature[f] = NULL;
1132 }
1133 
1134 void
1135 dsl_dataset_deactivate_feature(dsl_dataset_t *ds, spa_feature_t f, dmu_tx_t *tx)
1136 {
1137 	unload_zfeature(ds, f);
1138 	dsl_dataset_deactivate_feature_impl(ds, f, tx);
1139 }
1140 
1141 uint64_t
1142 dsl_dataset_create_sync_dd(dsl_dir_t *dd, dsl_dataset_t *origin,
1143     dsl_crypto_params_t *dcp, uint64_t flags, dmu_tx_t *tx)
1144 {
1145 	dsl_pool_t *dp = dd->dd_pool;
1146 	dmu_buf_t *dbuf;
1147 	dsl_dataset_phys_t *dsphys;
1148 	uint64_t dsobj;
1149 	objset_t *mos = dp->dp_meta_objset;
1150 
1151 	if (origin == NULL)
1152 		origin = dp->dp_origin_snap;
1153 
1154 	ASSERT(origin == NULL || origin->ds_dir->dd_pool == dp);
1155 	ASSERT(origin == NULL || dsl_dataset_phys(origin)->ds_num_children > 0);
1156 	ASSERT(dmu_tx_is_syncing(tx));
1157 	ASSERT(dsl_dir_phys(dd)->dd_head_dataset_obj == 0);
1158 
1159 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1160 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1161 	VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1162 	dmu_buf_will_dirty(dbuf, tx);
1163 	dsphys = dbuf->db_data;
1164 	memset(dsphys, 0, sizeof (dsl_dataset_phys_t));
1165 	dsphys->ds_dir_obj = dd->dd_object;
1166 	dsphys->ds_flags = flags;
1167 	dsphys->ds_fsid_guid = unique_create();
1168 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1169 	    sizeof (dsphys->ds_guid));
1170 	dsphys->ds_snapnames_zapobj =
1171 	    zap_create_norm(mos, U8_TEXTPREP_TOUPPER, DMU_OT_DSL_DS_SNAP_MAP,
1172 	    DMU_OT_NONE, 0, tx);
1173 	dsphys->ds_creation_time = gethrestime_sec();
1174 	dsphys->ds_creation_txg = tx->tx_txg == TXG_INITIAL ? 1 : tx->tx_txg;
1175 
1176 	if (origin == NULL) {
1177 		dsphys->ds_deadlist_obj = dsl_deadlist_alloc(mos, tx);
1178 	} else {
1179 		dsl_dataset_t *ohds; /* head of the origin snapshot */
1180 
1181 		dsphys->ds_prev_snap_obj = origin->ds_object;
1182 		dsphys->ds_prev_snap_txg =
1183 		    dsl_dataset_phys(origin)->ds_creation_txg;
1184 		dsphys->ds_referenced_bytes =
1185 		    dsl_dataset_phys(origin)->ds_referenced_bytes;
1186 		dsphys->ds_compressed_bytes =
1187 		    dsl_dataset_phys(origin)->ds_compressed_bytes;
1188 		dsphys->ds_uncompressed_bytes =
1189 		    dsl_dataset_phys(origin)->ds_uncompressed_bytes;
1190 		rrw_enter(&origin->ds_bp_rwlock, RW_READER, FTAG);
1191 		dsphys->ds_bp = dsl_dataset_phys(origin)->ds_bp;
1192 		rrw_exit(&origin->ds_bp_rwlock, FTAG);
1193 
1194 		/*
1195 		 * Inherit flags that describe the dataset's contents
1196 		 * (INCONSISTENT) or properties (Case Insensitive).
1197 		 */
1198 		dsphys->ds_flags |= dsl_dataset_phys(origin)->ds_flags &
1199 		    (DS_FLAG_INCONSISTENT | DS_FLAG_CI_DATASET);
1200 
1201 		for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1202 			if (zfeature_active(f, origin->ds_feature[f])) {
1203 				dsl_dataset_activate_feature(dsobj, f,
1204 				    origin->ds_feature[f], tx);
1205 			}
1206 		}
1207 
1208 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
1209 		dsl_dataset_phys(origin)->ds_num_children++;
1210 
1211 		VERIFY0(dsl_dataset_hold_obj(dp,
1212 		    dsl_dir_phys(origin->ds_dir)->dd_head_dataset_obj,
1213 		    FTAG, &ohds));
1214 		dsphys->ds_deadlist_obj = dsl_deadlist_clone(&ohds->ds_deadlist,
1215 		    dsphys->ds_prev_snap_txg, dsphys->ds_prev_snap_obj, tx);
1216 		dsl_dataset_rele(ohds, FTAG);
1217 
1218 		if (spa_version(dp->dp_spa) >= SPA_VERSION_NEXT_CLONES) {
1219 			if (dsl_dataset_phys(origin)->ds_next_clones_obj == 0) {
1220 				dsl_dataset_phys(origin)->ds_next_clones_obj =
1221 				    zap_create(mos,
1222 				    DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
1223 			}
1224 			VERIFY0(zap_add_int(mos,
1225 			    dsl_dataset_phys(origin)->ds_next_clones_obj,
1226 			    dsobj, tx));
1227 		}
1228 
1229 		dmu_buf_will_dirty(dd->dd_dbuf, tx);
1230 		dsl_dir_phys(dd)->dd_origin_obj = origin->ds_object;
1231 		if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
1232 			if (dsl_dir_phys(origin->ds_dir)->dd_clones == 0) {
1233 				dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
1234 				dsl_dir_phys(origin->ds_dir)->dd_clones =
1235 				    zap_create(mos,
1236 				    DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
1237 			}
1238 			VERIFY0(zap_add_int(mos,
1239 			    dsl_dir_phys(origin->ds_dir)->dd_clones,
1240 			    dsobj, tx));
1241 		}
1242 	}
1243 
1244 	/* handle encryption */
1245 	dsl_dataset_create_crypt_sync(dsobj, dd, origin, dcp, tx);
1246 
1247 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1248 		dsphys->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1249 
1250 	dmu_buf_rele(dbuf, FTAG);
1251 
1252 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
1253 	dsl_dir_phys(dd)->dd_head_dataset_obj = dsobj;
1254 
1255 	return (dsobj);
1256 }
1257 
1258 static void
1259 dsl_dataset_zero_zil(dsl_dataset_t *ds, dmu_tx_t *tx)
1260 {
1261 	objset_t *os;
1262 
1263 	VERIFY0(dmu_objset_from_ds(ds, &os));
1264 	if (memcmp(&os->os_zil_header, &zero_zil, sizeof (zero_zil)) != 0) {
1265 		dsl_pool_t *dp = ds->ds_dir->dd_pool;
1266 		zio_t *zio;
1267 
1268 		memset(&os->os_zil_header, 0, sizeof (os->os_zil_header));
1269 		if (os->os_encrypted)
1270 			os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_TRUE;
1271 
1272 		zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
1273 		dsl_dataset_sync(ds, zio, tx);
1274 		VERIFY0(zio_wait(zio));
1275 
1276 		/* dsl_dataset_sync_done will drop this reference. */
1277 		dmu_buf_add_ref(ds->ds_dbuf, ds);
1278 		dsl_dataset_sync_done(ds, tx);
1279 	}
1280 }
1281 
1282 uint64_t
1283 dsl_dataset_create_sync(dsl_dir_t *pdd, const char *lastname,
1284     dsl_dataset_t *origin, uint64_t flags, cred_t *cr,
1285     dsl_crypto_params_t *dcp, dmu_tx_t *tx)
1286 {
1287 	dsl_pool_t *dp = pdd->dd_pool;
1288 	uint64_t dsobj, ddobj;
1289 	dsl_dir_t *dd;
1290 
1291 	ASSERT(dmu_tx_is_syncing(tx));
1292 	ASSERT(lastname[0] != '@');
1293 	/*
1294 	 * Filesystems will eventually have their origin set to dp_origin_snap,
1295 	 * but that's taken care of in dsl_dataset_create_sync_dd. When
1296 	 * creating a filesystem, this function is called with origin equal to
1297 	 * NULL.
1298 	 */
1299 	if (origin != NULL)
1300 		ASSERT3P(origin, !=, dp->dp_origin_snap);
1301 
1302 	ddobj = dsl_dir_create_sync(dp, pdd, lastname, tx);
1303 	VERIFY0(dsl_dir_hold_obj(dp, ddobj, lastname, FTAG, &dd));
1304 
1305 	dsobj = dsl_dataset_create_sync_dd(dd, origin, dcp,
1306 	    flags & ~DS_CREATE_FLAG_NODIRTY, tx);
1307 
1308 	dsl_deleg_set_create_perms(dd, tx, cr);
1309 
1310 	/*
1311 	 * If we are creating a clone and the livelist feature is enabled,
1312 	 * add the entry DD_FIELD_LIVELIST to ZAP.
1313 	 */
1314 	if (origin != NULL &&
1315 	    spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_LIVELIST)) {
1316 		objset_t *mos = dd->dd_pool->dp_meta_objset;
1317 		dsl_dir_zapify(dd, tx);
1318 		uint64_t obj = dsl_deadlist_alloc(mos, tx);
1319 		VERIFY0(zap_add(mos, dd->dd_object, DD_FIELD_LIVELIST,
1320 		    sizeof (uint64_t), 1, &obj, tx));
1321 		spa_feature_incr(dp->dp_spa, SPA_FEATURE_LIVELIST, tx);
1322 	}
1323 
1324 	/*
1325 	 * Since we're creating a new node we know it's a leaf, so we can
1326 	 * initialize the counts if the limit feature is active.
1327 	 */
1328 	if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_FS_SS_LIMIT)) {
1329 		uint64_t cnt = 0;
1330 		objset_t *os = dd->dd_pool->dp_meta_objset;
1331 
1332 		dsl_dir_zapify(dd, tx);
1333 		VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_FILESYSTEM_COUNT,
1334 		    sizeof (cnt), 1, &cnt, tx));
1335 		VERIFY0(zap_add(os, dd->dd_object, DD_FIELD_SNAPSHOT_COUNT,
1336 		    sizeof (cnt), 1, &cnt, tx));
1337 	}
1338 
1339 	dsl_dir_rele(dd, FTAG);
1340 
1341 	/*
1342 	 * If we are creating a clone, make sure we zero out any stale
1343 	 * data from the origin snapshots zil header.
1344 	 */
1345 	if (origin != NULL && !(flags & DS_CREATE_FLAG_NODIRTY)) {
1346 		dsl_dataset_t *ds;
1347 
1348 		VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1349 		dsl_dataset_zero_zil(ds, tx);
1350 		dsl_dataset_rele(ds, FTAG);
1351 	}
1352 
1353 	return (dsobj);
1354 }
1355 
1356 /*
1357  * The unique space in the head dataset can be calculated by subtracting
1358  * the space used in the most recent snapshot, that is still being used
1359  * in this file system, from the space currently in use.  To figure out
1360  * the space in the most recent snapshot still in use, we need to take
1361  * the total space used in the snapshot and subtract out the space that
1362  * has been freed up since the snapshot was taken.
1363  */
1364 void
1365 dsl_dataset_recalc_head_uniq(dsl_dataset_t *ds)
1366 {
1367 	uint64_t mrs_used;
1368 	uint64_t dlused, dlcomp, dluncomp;
1369 
1370 	ASSERT(!ds->ds_is_snapshot);
1371 
1372 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0)
1373 		mrs_used = dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes;
1374 	else
1375 		mrs_used = 0;
1376 
1377 	dsl_deadlist_space(&ds->ds_deadlist, &dlused, &dlcomp, &dluncomp);
1378 
1379 	ASSERT3U(dlused, <=, mrs_used);
1380 	dsl_dataset_phys(ds)->ds_unique_bytes =
1381 	    dsl_dataset_phys(ds)->ds_referenced_bytes - (mrs_used - dlused);
1382 
1383 	if (spa_version(ds->ds_dir->dd_pool->dp_spa) >=
1384 	    SPA_VERSION_UNIQUE_ACCURATE)
1385 		dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1386 }
1387 
1388 void
1389 dsl_dataset_remove_from_next_clones(dsl_dataset_t *ds, uint64_t obj,
1390     dmu_tx_t *tx)
1391 {
1392 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
1393 	uint64_t count __maybe_unused;
1394 	int err;
1395 
1396 	ASSERT(dsl_dataset_phys(ds)->ds_num_children >= 2);
1397 	err = zap_remove_int(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
1398 	    obj, tx);
1399 	/*
1400 	 * The err should not be ENOENT, but a bug in a previous version
1401 	 * of the code could cause upgrade_clones_cb() to not set
1402 	 * ds_next_snap_obj when it should, leading to a missing entry.
1403 	 * If we knew that the pool was created after
1404 	 * SPA_VERSION_NEXT_CLONES, we could assert that it isn't
1405 	 * ENOENT.  However, at least we can check that we don't have
1406 	 * too many entries in the next_clones_obj even after failing to
1407 	 * remove this one.
1408 	 */
1409 	if (err != ENOENT)
1410 		VERIFY0(err);
1411 	ASSERT0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
1412 	    &count));
1413 	ASSERT3U(count, <=, dsl_dataset_phys(ds)->ds_num_children - 2);
1414 }
1415 
1416 
1417 blkptr_t *
1418 dsl_dataset_get_blkptr(dsl_dataset_t *ds)
1419 {
1420 	return (&dsl_dataset_phys(ds)->ds_bp);
1421 }
1422 
1423 spa_t *
1424 dsl_dataset_get_spa(dsl_dataset_t *ds)
1425 {
1426 	return (ds->ds_dir->dd_pool->dp_spa);
1427 }
1428 
1429 void
1430 dsl_dataset_dirty(dsl_dataset_t *ds, dmu_tx_t *tx)
1431 {
1432 	dsl_pool_t *dp;
1433 
1434 	if (ds == NULL) /* this is the meta-objset */
1435 		return;
1436 
1437 	ASSERT(ds->ds_objset != NULL);
1438 
1439 	if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0)
1440 		panic("dirtying snapshot!");
1441 
1442 	/* Must not dirty a dataset in the same txg where it got snapshotted. */
1443 	ASSERT3U(tx->tx_txg, >, dsl_dataset_phys(ds)->ds_prev_snap_txg);
1444 
1445 	dp = ds->ds_dir->dd_pool;
1446 	if (txg_list_add(&dp->dp_dirty_datasets, ds, tx->tx_txg)) {
1447 		objset_t *os = ds->ds_objset;
1448 
1449 		/* up the hold count until we can be written out */
1450 		dmu_buf_add_ref(ds->ds_dbuf, ds);
1451 
1452 		/* if this dataset is encrypted, grab a reference to the DCK */
1453 		if (ds->ds_dir->dd_crypto_obj != 0 &&
1454 		    !os->os_raw_receive &&
1455 		    !os->os_next_write_raw[tx->tx_txg & TXG_MASK]) {
1456 			ASSERT3P(ds->ds_key_mapping, !=, NULL);
1457 			key_mapping_add_ref(ds->ds_key_mapping, ds);
1458 		}
1459 	}
1460 }
1461 
1462 static int
1463 dsl_dataset_snapshot_reserve_space(dsl_dataset_t *ds, dmu_tx_t *tx)
1464 {
1465 	uint64_t asize;
1466 
1467 	if (!dmu_tx_is_syncing(tx))
1468 		return (0);
1469 
1470 	/*
1471 	 * If there's an fs-only reservation, any blocks that might become
1472 	 * owned by the snapshot dataset must be accommodated by space
1473 	 * outside of the reservation.
1474 	 */
1475 	ASSERT(ds->ds_reserved == 0 || DS_UNIQUE_IS_ACCURATE(ds));
1476 	asize = MIN(dsl_dataset_phys(ds)->ds_unique_bytes, ds->ds_reserved);
1477 	if (asize > dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE))
1478 		return (SET_ERROR(ENOSPC));
1479 
1480 	/*
1481 	 * Propagate any reserved space for this snapshot to other
1482 	 * snapshot checks in this sync group.
1483 	 */
1484 	if (asize > 0)
1485 		dsl_dir_willuse_space(ds->ds_dir, asize, tx);
1486 
1487 	return (0);
1488 }
1489 
1490 int
1491 dsl_dataset_snapshot_check_impl(dsl_dataset_t *ds, const char *snapname,
1492     dmu_tx_t *tx, boolean_t recv, uint64_t cnt, cred_t *cr, proc_t *proc)
1493 {
1494 	int error;
1495 	uint64_t value;
1496 
1497 	ds->ds_trysnap_txg = tx->tx_txg;
1498 
1499 	if (!dmu_tx_is_syncing(tx))
1500 		return (0);
1501 
1502 	/*
1503 	 * We don't allow multiple snapshots of the same txg.  If there
1504 	 * is already one, try again.
1505 	 */
1506 	if (dsl_dataset_phys(ds)->ds_prev_snap_txg >= tx->tx_txg)
1507 		return (SET_ERROR(EAGAIN));
1508 
1509 	/*
1510 	 * Check for conflicting snapshot name.
1511 	 */
1512 	error = dsl_dataset_snap_lookup(ds, snapname, &value);
1513 	if (error == 0)
1514 		return (SET_ERROR(EEXIST));
1515 	if (error != ENOENT)
1516 		return (error);
1517 
1518 	/*
1519 	 * We don't allow taking snapshots of inconsistent datasets, such as
1520 	 * those into which we are currently receiving.  However, if we are
1521 	 * creating this snapshot as part of a receive, this check will be
1522 	 * executed atomically with respect to the completion of the receive
1523 	 * itself but prior to the clearing of DS_FLAG_INCONSISTENT; in this
1524 	 * case we ignore this, knowing it will be fixed up for us shortly in
1525 	 * dmu_recv_end_sync().
1526 	 */
1527 	if (!recv && DS_IS_INCONSISTENT(ds))
1528 		return (SET_ERROR(EBUSY));
1529 
1530 	/*
1531 	 * Skip the check for temporary snapshots or if we have already checked
1532 	 * the counts in dsl_dataset_snapshot_check. This means we really only
1533 	 * check the count here when we're receiving a stream.
1534 	 */
1535 	if (cnt != 0 && cr != NULL) {
1536 		error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1537 		    ZFS_PROP_SNAPSHOT_LIMIT, NULL, cr, proc);
1538 		if (error != 0)
1539 			return (error);
1540 	}
1541 
1542 	error = dsl_dataset_snapshot_reserve_space(ds, tx);
1543 	if (error != 0)
1544 		return (error);
1545 
1546 	return (0);
1547 }
1548 
1549 int
1550 dsl_dataset_snapshot_check(void *arg, dmu_tx_t *tx)
1551 {
1552 	dsl_dataset_snapshot_arg_t *ddsa = arg;
1553 	dsl_pool_t *dp = dmu_tx_pool(tx);
1554 	nvpair_t *pair;
1555 	int rv = 0;
1556 
1557 	/*
1558 	 * Pre-compute how many total new snapshots will be created for each
1559 	 * level in the tree and below. This is needed for validating the
1560 	 * snapshot limit when either taking a recursive snapshot or when
1561 	 * taking multiple snapshots.
1562 	 *
1563 	 * The problem is that the counts are not actually adjusted when
1564 	 * we are checking, only when we finally sync. For a single snapshot,
1565 	 * this is easy, the count will increase by 1 at each node up the tree,
1566 	 * but its more complicated for the recursive/multiple snapshot case.
1567 	 *
1568 	 * The dsl_fs_ss_limit_check function does recursively check the count
1569 	 * at each level up the tree but since it is validating each snapshot
1570 	 * independently we need to be sure that we are validating the complete
1571 	 * count for the entire set of snapshots. We do this by rolling up the
1572 	 * counts for each component of the name into an nvlist and then
1573 	 * checking each of those cases with the aggregated count.
1574 	 *
1575 	 * This approach properly handles not only the recursive snapshot
1576 	 * case (where we get all of those on the ddsa_snaps list) but also
1577 	 * the sibling case (e.g. snapshot a/b and a/c so that we will also
1578 	 * validate the limit on 'a' using a count of 2).
1579 	 *
1580 	 * We validate the snapshot names in the third loop and only report
1581 	 * name errors once.
1582 	 */
1583 	if (dmu_tx_is_syncing(tx)) {
1584 		char *nm;
1585 		nvlist_t *cnt_track = NULL;
1586 		cnt_track = fnvlist_alloc();
1587 
1588 		nm = kmem_alloc(MAXPATHLEN, KM_SLEEP);
1589 
1590 		/* Rollup aggregated counts into the cnt_track list */
1591 		for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1592 		    pair != NULL;
1593 		    pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1594 			char *pdelim;
1595 			uint64_t val;
1596 
1597 			(void) strlcpy(nm, nvpair_name(pair), MAXPATHLEN);
1598 			pdelim = strchr(nm, '@');
1599 			if (pdelim == NULL)
1600 				continue;
1601 			*pdelim = '\0';
1602 
1603 			do {
1604 				if (nvlist_lookup_uint64(cnt_track, nm,
1605 				    &val) == 0) {
1606 					/* update existing entry */
1607 					fnvlist_add_uint64(cnt_track, nm,
1608 					    val + 1);
1609 				} else {
1610 					/* add to list */
1611 					fnvlist_add_uint64(cnt_track, nm, 1);
1612 				}
1613 
1614 				pdelim = strrchr(nm, '/');
1615 				if (pdelim != NULL)
1616 					*pdelim = '\0';
1617 			} while (pdelim != NULL);
1618 		}
1619 
1620 		kmem_free(nm, MAXPATHLEN);
1621 
1622 		/* Check aggregated counts at each level */
1623 		for (pair = nvlist_next_nvpair(cnt_track, NULL);
1624 		    pair != NULL; pair = nvlist_next_nvpair(cnt_track, pair)) {
1625 			int error = 0;
1626 			char *name;
1627 			uint64_t cnt = 0;
1628 			dsl_dataset_t *ds;
1629 
1630 			name = nvpair_name(pair);
1631 			cnt = fnvpair_value_uint64(pair);
1632 			ASSERT(cnt > 0);
1633 
1634 			error = dsl_dataset_hold(dp, name, FTAG, &ds);
1635 			if (error == 0) {
1636 				error = dsl_fs_ss_limit_check(ds->ds_dir, cnt,
1637 				    ZFS_PROP_SNAPSHOT_LIMIT, NULL,
1638 				    ddsa->ddsa_cr, ddsa->ddsa_proc);
1639 				dsl_dataset_rele(ds, FTAG);
1640 			}
1641 
1642 			if (error != 0) {
1643 				if (ddsa->ddsa_errors != NULL)
1644 					fnvlist_add_int32(ddsa->ddsa_errors,
1645 					    name, error);
1646 				rv = error;
1647 				/* only report one error for this check */
1648 				break;
1649 			}
1650 		}
1651 		nvlist_free(cnt_track);
1652 	}
1653 
1654 	for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1655 	    pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1656 		int error = 0;
1657 		dsl_dataset_t *ds;
1658 		char *name, *atp = NULL;
1659 		char dsname[ZFS_MAX_DATASET_NAME_LEN];
1660 
1661 		name = nvpair_name(pair);
1662 		if (strlen(name) >= ZFS_MAX_DATASET_NAME_LEN)
1663 			error = SET_ERROR(ENAMETOOLONG);
1664 		if (error == 0) {
1665 			atp = strchr(name, '@');
1666 			if (atp == NULL)
1667 				error = SET_ERROR(EINVAL);
1668 			if (error == 0)
1669 				(void) strlcpy(dsname, name, atp - name + 1);
1670 		}
1671 		if (error == 0)
1672 			error = dsl_dataset_hold(dp, dsname, FTAG, &ds);
1673 		if (error == 0) {
1674 			/* passing 0/NULL skips dsl_fs_ss_limit_check */
1675 			error = dsl_dataset_snapshot_check_impl(ds,
1676 			    atp + 1, tx, B_FALSE, 0, NULL, NULL);
1677 			dsl_dataset_rele(ds, FTAG);
1678 		}
1679 
1680 		if (error != 0) {
1681 			if (ddsa->ddsa_errors != NULL) {
1682 				fnvlist_add_int32(ddsa->ddsa_errors,
1683 				    name, error);
1684 			}
1685 			rv = error;
1686 		}
1687 	}
1688 
1689 	return (rv);
1690 }
1691 
1692 void
1693 dsl_dataset_snapshot_sync_impl(dsl_dataset_t *ds, const char *snapname,
1694     dmu_tx_t *tx)
1695 {
1696 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
1697 	dmu_buf_t *dbuf;
1698 	dsl_dataset_phys_t *dsphys;
1699 	uint64_t dsobj, crtxg;
1700 	objset_t *mos = dp->dp_meta_objset;
1701 	static zil_header_t zero_zil __maybe_unused;
1702 	objset_t *os __maybe_unused;
1703 
1704 	ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
1705 
1706 	/*
1707 	 * If we are on an old pool, the zil must not be active, in which
1708 	 * case it will be zeroed.  Usually zil_suspend() accomplishes this.
1709 	 */
1710 	ASSERT(spa_version(dmu_tx_pool(tx)->dp_spa) >= SPA_VERSION_FAST_SNAP ||
1711 	    dmu_objset_from_ds(ds, &os) != 0 ||
1712 	    memcmp(&os->os_phys->os_zil_header, &zero_zil,
1713 	    sizeof (zero_zil)) == 0);
1714 
1715 	/* Should not snapshot a dirty dataset. */
1716 	ASSERT(!txg_list_member(&ds->ds_dir->dd_pool->dp_dirty_datasets,
1717 	    ds, tx->tx_txg));
1718 
1719 	dsl_fs_ss_count_adjust(ds->ds_dir, 1, DD_FIELD_SNAPSHOT_COUNT, tx);
1720 
1721 	/*
1722 	 * The origin's ds_creation_txg has to be < TXG_INITIAL
1723 	 */
1724 	if (strcmp(snapname, ORIGIN_DIR_NAME) == 0)
1725 		crtxg = 1;
1726 	else
1727 		crtxg = tx->tx_txg;
1728 
1729 	dsobj = dmu_object_alloc(mos, DMU_OT_DSL_DATASET, 0,
1730 	    DMU_OT_DSL_DATASET, sizeof (dsl_dataset_phys_t), tx);
1731 	VERIFY0(dmu_bonus_hold(mos, dsobj, FTAG, &dbuf));
1732 	dmu_buf_will_dirty(dbuf, tx);
1733 	dsphys = dbuf->db_data;
1734 	memset(dsphys, 0, sizeof (dsl_dataset_phys_t));
1735 	dsphys->ds_dir_obj = ds->ds_dir->dd_object;
1736 	dsphys->ds_fsid_guid = unique_create();
1737 	(void) random_get_pseudo_bytes((void*)&dsphys->ds_guid,
1738 	    sizeof (dsphys->ds_guid));
1739 	dsphys->ds_prev_snap_obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
1740 	dsphys->ds_prev_snap_txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
1741 	dsphys->ds_next_snap_obj = ds->ds_object;
1742 	dsphys->ds_num_children = 1;
1743 	dsphys->ds_creation_time = gethrestime_sec();
1744 	dsphys->ds_creation_txg = crtxg;
1745 	dsphys->ds_deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
1746 	dsphys->ds_referenced_bytes = dsl_dataset_phys(ds)->ds_referenced_bytes;
1747 	dsphys->ds_compressed_bytes = dsl_dataset_phys(ds)->ds_compressed_bytes;
1748 	dsphys->ds_uncompressed_bytes =
1749 	    dsl_dataset_phys(ds)->ds_uncompressed_bytes;
1750 	dsphys->ds_flags = dsl_dataset_phys(ds)->ds_flags;
1751 	rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
1752 	dsphys->ds_bp = dsl_dataset_phys(ds)->ds_bp;
1753 	rrw_exit(&ds->ds_bp_rwlock, FTAG);
1754 	dmu_buf_rele(dbuf, FTAG);
1755 
1756 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
1757 		if (zfeature_active(f, ds->ds_feature[f])) {
1758 			dsl_dataset_activate_feature(dsobj, f,
1759 			    ds->ds_feature[f], tx);
1760 		}
1761 	}
1762 
1763 	ASSERT3U(ds->ds_prev != 0, ==,
1764 	    dsl_dataset_phys(ds)->ds_prev_snap_obj != 0);
1765 	if (ds->ds_prev) {
1766 		uint64_t next_clones_obj =
1767 		    dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj;
1768 		ASSERT(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1769 		    ds->ds_object ||
1770 		    dsl_dataset_phys(ds->ds_prev)->ds_num_children > 1);
1771 		if (dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj ==
1772 		    ds->ds_object) {
1773 			dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
1774 			ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
1775 			    dsl_dataset_phys(ds->ds_prev)->ds_creation_txg);
1776 			dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj = dsobj;
1777 		} else if (next_clones_obj != 0) {
1778 			dsl_dataset_remove_from_next_clones(ds->ds_prev,
1779 			    dsphys->ds_next_snap_obj, tx);
1780 			VERIFY0(zap_add_int(mos,
1781 			    next_clones_obj, dsobj, tx));
1782 		}
1783 	}
1784 
1785 	/*
1786 	 * If we have a reference-reservation on this dataset, we will
1787 	 * need to increase the amount of refreservation being charged
1788 	 * since our unique space is going to zero.
1789 	 */
1790 	if (ds->ds_reserved) {
1791 		int64_t delta;
1792 		ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
1793 		delta = MIN(dsl_dataset_phys(ds)->ds_unique_bytes,
1794 		    ds->ds_reserved);
1795 		dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV,
1796 		    delta, 0, 0, tx);
1797 	}
1798 
1799 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
1800 	dsl_dataset_phys(ds)->ds_deadlist_obj =
1801 	    dsl_deadlist_clone(&ds->ds_deadlist, UINT64_MAX,
1802 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, tx);
1803 	dsl_deadlist_close(&ds->ds_deadlist);
1804 	dsl_deadlist_open(&ds->ds_deadlist, mos,
1805 	    dsl_dataset_phys(ds)->ds_deadlist_obj);
1806 	dsl_deadlist_add_key(&ds->ds_deadlist,
1807 	    dsl_dataset_phys(ds)->ds_prev_snap_txg, tx);
1808 	dsl_bookmark_snapshotted(ds, tx);
1809 
1810 	if (dsl_dataset_remap_deadlist_exists(ds)) {
1811 		uint64_t remap_deadlist_obj =
1812 		    dsl_dataset_get_remap_deadlist_object(ds);
1813 		/*
1814 		 * Move the remap_deadlist to the snapshot.  The head
1815 		 * will create a new remap deadlist on demand, from
1816 		 * dsl_dataset_block_remapped().
1817 		 */
1818 		dsl_dataset_unset_remap_deadlist_object(ds, tx);
1819 		dsl_deadlist_close(&ds->ds_remap_deadlist);
1820 
1821 		dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
1822 		VERIFY0(zap_add(mos, dsobj, DS_FIELD_REMAP_DEADLIST,
1823 		    sizeof (remap_deadlist_obj), 1, &remap_deadlist_obj, tx));
1824 	}
1825 
1826 	/*
1827 	 * Create a ivset guid for this snapshot if the dataset is
1828 	 * encrypted. This may be overridden by a raw receive. A
1829 	 * previous implementation of this code did not have this
1830 	 * field as part of the on-disk format for ZFS encryption
1831 	 * (see errata #4). As part of the remediation for this
1832 	 * issue, we ask the user to enable the bookmark_v2 feature
1833 	 * which is now a dependency of the encryption feature. We
1834 	 * use this as a heuristic to determine when the user has
1835 	 * elected to correct any datasets created with the old code.
1836 	 * As a result, we only do this step if the bookmark_v2
1837 	 * feature is enabled, which limits the number of states a
1838 	 * given pool / dataset can be in with regards to terms of
1839 	 * correcting the issue.
1840 	 */
1841 	if (ds->ds_dir->dd_crypto_obj != 0 &&
1842 	    spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_BOOKMARK_V2)) {
1843 		uint64_t ivset_guid = unique_create();
1844 
1845 		dmu_object_zapify(mos, dsobj, DMU_OT_DSL_DATASET, tx);
1846 		VERIFY0(zap_add(mos, dsobj, DS_FIELD_IVSET_GUID,
1847 		    sizeof (ivset_guid), 1, &ivset_guid, tx));
1848 	}
1849 
1850 	ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, <, tx->tx_txg);
1851 	dsl_dataset_phys(ds)->ds_prev_snap_obj = dsobj;
1852 	dsl_dataset_phys(ds)->ds_prev_snap_txg = crtxg;
1853 	dsl_dataset_phys(ds)->ds_unique_bytes = 0;
1854 
1855 	if (spa_version(dp->dp_spa) >= SPA_VERSION_UNIQUE_ACCURATE)
1856 		dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_UNIQUE_ACCURATE;
1857 
1858 	VERIFY0(zap_add(mos, dsl_dataset_phys(ds)->ds_snapnames_zapobj,
1859 	    snapname, 8, 1, &dsobj, tx));
1860 
1861 	if (ds->ds_prev)
1862 		dsl_dataset_rele(ds->ds_prev, ds);
1863 	VERIFY0(dsl_dataset_hold_obj(dp,
1864 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, ds, &ds->ds_prev));
1865 
1866 	dsl_scan_ds_snapshotted(ds, tx);
1867 
1868 	dsl_dir_snap_cmtime_update(ds->ds_dir, tx);
1869 
1870 	if (zfs_snapshot_history_enabled)
1871 		spa_history_log_internal_ds(ds->ds_prev, "snapshot", tx, " ");
1872 }
1873 
1874 void
1875 dsl_dataset_snapshot_sync(void *arg, dmu_tx_t *tx)
1876 {
1877 	dsl_dataset_snapshot_arg_t *ddsa = arg;
1878 	dsl_pool_t *dp = dmu_tx_pool(tx);
1879 	nvpair_t *pair;
1880 
1881 	for (pair = nvlist_next_nvpair(ddsa->ddsa_snaps, NULL);
1882 	    pair != NULL; pair = nvlist_next_nvpair(ddsa->ddsa_snaps, pair)) {
1883 		dsl_dataset_t *ds;
1884 		char *name, *atp;
1885 		char dsname[ZFS_MAX_DATASET_NAME_LEN];
1886 
1887 		name = nvpair_name(pair);
1888 		atp = strchr(name, '@');
1889 		(void) strlcpy(dsname, name, atp - name + 1);
1890 		VERIFY0(dsl_dataset_hold(dp, dsname, FTAG, &ds));
1891 
1892 		dsl_dataset_snapshot_sync_impl(ds, atp + 1, tx);
1893 		if (ddsa->ddsa_props != NULL) {
1894 			dsl_props_set_sync_impl(ds->ds_prev,
1895 			    ZPROP_SRC_LOCAL, ddsa->ddsa_props, tx);
1896 		}
1897 		dsl_dataset_rele(ds, FTAG);
1898 	}
1899 }
1900 
1901 /*
1902  * The snapshots must all be in the same pool.
1903  * All-or-nothing: if there are any failures, nothing will be modified.
1904  */
1905 int
1906 dsl_dataset_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t *errors)
1907 {
1908 	dsl_dataset_snapshot_arg_t ddsa;
1909 	nvpair_t *pair;
1910 	boolean_t needsuspend;
1911 	int error;
1912 	spa_t *spa;
1913 	char *firstname;
1914 	nvlist_t *suspended = NULL;
1915 
1916 	pair = nvlist_next_nvpair(snaps, NULL);
1917 	if (pair == NULL)
1918 		return (0);
1919 	firstname = nvpair_name(pair);
1920 
1921 	error = spa_open(firstname, &spa, FTAG);
1922 	if (error != 0)
1923 		return (error);
1924 	needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
1925 	spa_close(spa, FTAG);
1926 
1927 	if (needsuspend) {
1928 		suspended = fnvlist_alloc();
1929 		for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
1930 		    pair = nvlist_next_nvpair(snaps, pair)) {
1931 			char fsname[ZFS_MAX_DATASET_NAME_LEN];
1932 			char *snapname = nvpair_name(pair);
1933 			char *atp;
1934 			void *cookie;
1935 
1936 			atp = strchr(snapname, '@');
1937 			if (atp == NULL) {
1938 				error = SET_ERROR(EINVAL);
1939 				break;
1940 			}
1941 			(void) strlcpy(fsname, snapname, atp - snapname + 1);
1942 
1943 			error = zil_suspend(fsname, &cookie);
1944 			if (error != 0)
1945 				break;
1946 			fnvlist_add_uint64(suspended, fsname,
1947 			    (uintptr_t)cookie);
1948 		}
1949 	}
1950 
1951 	ddsa.ddsa_snaps = snaps;
1952 	ddsa.ddsa_props = props;
1953 	ddsa.ddsa_errors = errors;
1954 	ddsa.ddsa_cr = CRED();
1955 	ddsa.ddsa_proc = curproc;
1956 
1957 	if (error == 0) {
1958 		error = dsl_sync_task(firstname, dsl_dataset_snapshot_check,
1959 		    dsl_dataset_snapshot_sync, &ddsa,
1960 		    fnvlist_num_pairs(snaps) * 3, ZFS_SPACE_CHECK_NORMAL);
1961 	}
1962 
1963 	if (suspended != NULL) {
1964 		for (pair = nvlist_next_nvpair(suspended, NULL); pair != NULL;
1965 		    pair = nvlist_next_nvpair(suspended, pair)) {
1966 			zil_resume((void *)(uintptr_t)
1967 			    fnvpair_value_uint64(pair));
1968 		}
1969 		fnvlist_free(suspended);
1970 	}
1971 
1972 	if (error == 0) {
1973 		for (pair = nvlist_next_nvpair(snaps, NULL); pair != NULL;
1974 		    pair = nvlist_next_nvpair(snaps, pair)) {
1975 			zvol_create_minor(nvpair_name(pair));
1976 		}
1977 	}
1978 
1979 	return (error);
1980 }
1981 
1982 typedef struct dsl_dataset_snapshot_tmp_arg {
1983 	const char *ddsta_fsname;
1984 	const char *ddsta_snapname;
1985 	minor_t ddsta_cleanup_minor;
1986 	const char *ddsta_htag;
1987 } dsl_dataset_snapshot_tmp_arg_t;
1988 
1989 static int
1990 dsl_dataset_snapshot_tmp_check(void *arg, dmu_tx_t *tx)
1991 {
1992 	dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
1993 	dsl_pool_t *dp = dmu_tx_pool(tx);
1994 	dsl_dataset_t *ds;
1995 	int error;
1996 
1997 	error = dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds);
1998 	if (error != 0)
1999 		return (error);
2000 
2001 	/* NULL cred means no limit check for tmp snapshot */
2002 	error = dsl_dataset_snapshot_check_impl(ds, ddsta->ddsta_snapname,
2003 	    tx, B_FALSE, 0, NULL, NULL);
2004 	if (error != 0) {
2005 		dsl_dataset_rele(ds, FTAG);
2006 		return (error);
2007 	}
2008 
2009 	if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS) {
2010 		dsl_dataset_rele(ds, FTAG);
2011 		return (SET_ERROR(ENOTSUP));
2012 	}
2013 	error = dsl_dataset_user_hold_check_one(NULL, ddsta->ddsta_htag,
2014 	    B_TRUE, tx);
2015 	if (error != 0) {
2016 		dsl_dataset_rele(ds, FTAG);
2017 		return (error);
2018 	}
2019 
2020 	dsl_dataset_rele(ds, FTAG);
2021 	return (0);
2022 }
2023 
2024 static void
2025 dsl_dataset_snapshot_tmp_sync(void *arg, dmu_tx_t *tx)
2026 {
2027 	dsl_dataset_snapshot_tmp_arg_t *ddsta = arg;
2028 	dsl_pool_t *dp = dmu_tx_pool(tx);
2029 	dsl_dataset_t *ds = NULL;
2030 
2031 	VERIFY0(dsl_dataset_hold(dp, ddsta->ddsta_fsname, FTAG, &ds));
2032 
2033 	dsl_dataset_snapshot_sync_impl(ds, ddsta->ddsta_snapname, tx);
2034 	dsl_dataset_user_hold_sync_one(ds->ds_prev, ddsta->ddsta_htag,
2035 	    ddsta->ddsta_cleanup_minor, gethrestime_sec(), tx);
2036 	dsl_destroy_snapshot_sync_impl(ds->ds_prev, B_TRUE, tx);
2037 
2038 	dsl_dataset_rele(ds, FTAG);
2039 }
2040 
2041 int
2042 dsl_dataset_snapshot_tmp(const char *fsname, const char *snapname,
2043     minor_t cleanup_minor, const char *htag)
2044 {
2045 	dsl_dataset_snapshot_tmp_arg_t ddsta;
2046 	int error;
2047 	spa_t *spa;
2048 	boolean_t needsuspend;
2049 	void *cookie;
2050 
2051 	ddsta.ddsta_fsname = fsname;
2052 	ddsta.ddsta_snapname = snapname;
2053 	ddsta.ddsta_cleanup_minor = cleanup_minor;
2054 	ddsta.ddsta_htag = htag;
2055 
2056 	error = spa_open(fsname, &spa, FTAG);
2057 	if (error != 0)
2058 		return (error);
2059 	needsuspend = (spa_version(spa) < SPA_VERSION_FAST_SNAP);
2060 	spa_close(spa, FTAG);
2061 
2062 	if (needsuspend) {
2063 		error = zil_suspend(fsname, &cookie);
2064 		if (error != 0)
2065 			return (error);
2066 	}
2067 
2068 	error = dsl_sync_task(fsname, dsl_dataset_snapshot_tmp_check,
2069 	    dsl_dataset_snapshot_tmp_sync, &ddsta, 3, ZFS_SPACE_CHECK_RESERVED);
2070 
2071 	if (needsuspend)
2072 		zil_resume(cookie);
2073 	return (error);
2074 }
2075 
2076 void
2077 dsl_dataset_sync(dsl_dataset_t *ds, zio_t *zio, dmu_tx_t *tx)
2078 {
2079 	ASSERT(dmu_tx_is_syncing(tx));
2080 	ASSERT(ds->ds_objset != NULL);
2081 	ASSERT(dsl_dataset_phys(ds)->ds_next_snap_obj == 0);
2082 
2083 	/*
2084 	 * in case we had to change ds_fsid_guid when we opened it,
2085 	 * sync it out now.
2086 	 */
2087 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
2088 	dsl_dataset_phys(ds)->ds_fsid_guid = ds->ds_fsid_guid;
2089 
2090 	if (ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] != 0) {
2091 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
2092 		    ds->ds_object, DS_FIELD_RESUME_OBJECT, 8, 1,
2093 		    &ds->ds_resume_object[tx->tx_txg & TXG_MASK], tx));
2094 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
2095 		    ds->ds_object, DS_FIELD_RESUME_OFFSET, 8, 1,
2096 		    &ds->ds_resume_offset[tx->tx_txg & TXG_MASK], tx));
2097 		VERIFY0(zap_update(tx->tx_pool->dp_meta_objset,
2098 		    ds->ds_object, DS_FIELD_RESUME_BYTES, 8, 1,
2099 		    &ds->ds_resume_bytes[tx->tx_txg & TXG_MASK], tx));
2100 		ds->ds_resume_object[tx->tx_txg & TXG_MASK] = 0;
2101 		ds->ds_resume_offset[tx->tx_txg & TXG_MASK] = 0;
2102 		ds->ds_resume_bytes[tx->tx_txg & TXG_MASK] = 0;
2103 	}
2104 
2105 	dmu_objset_sync(ds->ds_objset, zio, tx);
2106 
2107 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
2108 		if (zfeature_active(f, ds->ds_feature_activation[f])) {
2109 			if (zfeature_active(f, ds->ds_feature[f]))
2110 				continue;
2111 			dsl_dataset_activate_feature(ds->ds_object, f,
2112 			    ds->ds_feature_activation[f], tx);
2113 			ds->ds_feature[f] = ds->ds_feature_activation[f];
2114 		}
2115 	}
2116 }
2117 
2118 /*
2119  * Check if the percentage of blocks shared between the clone and the
2120  * snapshot (as opposed to those that are clone only) is below a certain
2121  * threshold
2122  */
2123 static boolean_t
2124 dsl_livelist_should_disable(dsl_dataset_t *ds)
2125 {
2126 	uint64_t used, referenced;
2127 	int percent_shared;
2128 
2129 	used = dsl_dir_get_usedds(ds->ds_dir);
2130 	referenced = dsl_get_referenced(ds);
2131 	if (referenced == 0)
2132 		return (B_FALSE);
2133 	percent_shared = (100 * (referenced - used)) / referenced;
2134 	if (percent_shared <= zfs_livelist_min_percent_shared)
2135 		return (B_TRUE);
2136 	return (B_FALSE);
2137 }
2138 
2139 /*
2140  *  Check if it is possible to combine two livelist entries into one.
2141  *  This is the case if the combined number of 'live' blkptrs (ALLOCs that
2142  *  don't have a matching FREE) is under the maximum sublist size.
2143  *  We check this by subtracting twice the total number of frees from the total
2144  *  number of blkptrs. FREEs are counted twice because each FREE blkptr
2145  *  will cancel out an ALLOC blkptr when the livelist is processed.
2146  */
2147 static boolean_t
2148 dsl_livelist_should_condense(dsl_deadlist_entry_t *first,
2149     dsl_deadlist_entry_t *next)
2150 {
2151 	uint64_t total_free = first->dle_bpobj.bpo_phys->bpo_num_freed +
2152 	    next->dle_bpobj.bpo_phys->bpo_num_freed;
2153 	uint64_t total_entries = first->dle_bpobj.bpo_phys->bpo_num_blkptrs +
2154 	    next->dle_bpobj.bpo_phys->bpo_num_blkptrs;
2155 	if ((total_entries - (2 * total_free)) < zfs_livelist_max_entries)
2156 		return (B_TRUE);
2157 	return (B_FALSE);
2158 }
2159 
2160 typedef struct try_condense_arg {
2161 	spa_t *spa;
2162 	dsl_dataset_t *ds;
2163 } try_condense_arg_t;
2164 
2165 /*
2166  * Iterate over the livelist entries, searching for a pair to condense.
2167  * A nonzero return value means stop, 0 means keep looking.
2168  */
2169 static int
2170 dsl_livelist_try_condense(void *arg, dsl_deadlist_entry_t *first)
2171 {
2172 	try_condense_arg_t *tca = arg;
2173 	spa_t *spa = tca->spa;
2174 	dsl_dataset_t *ds = tca->ds;
2175 	dsl_deadlist_t *ll = &ds->ds_dir->dd_livelist;
2176 	dsl_deadlist_entry_t *next;
2177 
2178 	/* The condense thread has not yet been created at import */
2179 	if (spa->spa_livelist_condense_zthr == NULL)
2180 		return (1);
2181 
2182 	/* A condense is already in progress */
2183 	if (spa->spa_to_condense.ds != NULL)
2184 		return (1);
2185 
2186 	next = AVL_NEXT(&ll->dl_tree, &first->dle_node);
2187 	/* The livelist has only one entry - don't condense it */
2188 	if (next == NULL)
2189 		return (1);
2190 
2191 	/* Next is the newest entry - don't condense it */
2192 	if (AVL_NEXT(&ll->dl_tree, &next->dle_node) == NULL)
2193 		return (1);
2194 
2195 	/* This pair is not ready to condense but keep looking */
2196 	if (!dsl_livelist_should_condense(first, next))
2197 		return (0);
2198 
2199 	/*
2200 	 * Add a ref to prevent the dataset from being evicted while
2201 	 * the condense zthr or synctask are running. Ref will be
2202 	 * released at the end of the condense synctask
2203 	 */
2204 	dmu_buf_add_ref(ds->ds_dbuf, spa);
2205 
2206 	spa->spa_to_condense.ds = ds;
2207 	spa->spa_to_condense.first = first;
2208 	spa->spa_to_condense.next = next;
2209 	spa->spa_to_condense.syncing = B_FALSE;
2210 	spa->spa_to_condense.cancelled = B_FALSE;
2211 
2212 	zthr_wakeup(spa->spa_livelist_condense_zthr);
2213 	return (1);
2214 }
2215 
2216 static void
2217 dsl_flush_pending_livelist(dsl_dataset_t *ds, dmu_tx_t *tx)
2218 {
2219 	dsl_dir_t *dd = ds->ds_dir;
2220 	spa_t *spa = ds->ds_dir->dd_pool->dp_spa;
2221 	dsl_deadlist_entry_t *last = dsl_deadlist_last(&dd->dd_livelist);
2222 
2223 	/* Check if we need to add a new sub-livelist */
2224 	if (last == NULL) {
2225 		/* The livelist is empty */
2226 		dsl_deadlist_add_key(&dd->dd_livelist,
2227 		    tx->tx_txg - 1, tx);
2228 	} else if (spa_sync_pass(spa) == 1) {
2229 		/*
2230 		 * Check if the newest entry is full. If it is, make a new one.
2231 		 * We only do this once per sync because we could overfill a
2232 		 * sublist in one sync pass and don't want to add another entry
2233 		 * for a txg that is already represented. This ensures that
2234 		 * blkptrs born in the same txg are stored in the same sublist.
2235 		 */
2236 		bpobj_t bpobj = last->dle_bpobj;
2237 		uint64_t all = bpobj.bpo_phys->bpo_num_blkptrs;
2238 		uint64_t free = bpobj.bpo_phys->bpo_num_freed;
2239 		uint64_t alloc = all - free;
2240 		if (alloc > zfs_livelist_max_entries) {
2241 			dsl_deadlist_add_key(&dd->dd_livelist,
2242 			    tx->tx_txg - 1, tx);
2243 		}
2244 	}
2245 
2246 	/* Insert each entry into the on-disk livelist */
2247 	bplist_iterate(&dd->dd_pending_allocs,
2248 	    dsl_deadlist_insert_alloc_cb, &dd->dd_livelist, tx);
2249 	bplist_iterate(&dd->dd_pending_frees,
2250 	    dsl_deadlist_insert_free_cb, &dd->dd_livelist, tx);
2251 
2252 	/* Attempt to condense every pair of adjacent entries */
2253 	try_condense_arg_t arg = {
2254 	    .spa = spa,
2255 	    .ds = ds
2256 	};
2257 	dsl_deadlist_iterate(&dd->dd_livelist, dsl_livelist_try_condense,
2258 	    &arg);
2259 }
2260 
2261 void
2262 dsl_dataset_sync_done(dsl_dataset_t *ds, dmu_tx_t *tx)
2263 {
2264 	objset_t *os = ds->ds_objset;
2265 
2266 	bplist_iterate(&ds->ds_pending_deadlist,
2267 	    dsl_deadlist_insert_alloc_cb, &ds->ds_deadlist, tx);
2268 
2269 	if (dsl_deadlist_is_open(&ds->ds_dir->dd_livelist)) {
2270 		dsl_flush_pending_livelist(ds, tx);
2271 		if (dsl_livelist_should_disable(ds)) {
2272 			dsl_dir_remove_livelist(ds->ds_dir, tx, B_TRUE);
2273 		}
2274 	}
2275 
2276 	dsl_bookmark_sync_done(ds, tx);
2277 
2278 	multilist_destroy(&os->os_synced_dnodes);
2279 
2280 	if (os->os_encrypted)
2281 		os->os_next_write_raw[tx->tx_txg & TXG_MASK] = B_FALSE;
2282 	else
2283 		ASSERT0(os->os_next_write_raw[tx->tx_txg & TXG_MASK]);
2284 
2285 	ASSERT(!dmu_objset_is_dirty(os, dmu_tx_get_txg(tx)));
2286 
2287 	dmu_buf_rele(ds->ds_dbuf, ds);
2288 }
2289 
2290 int
2291 get_clones_stat_impl(dsl_dataset_t *ds, nvlist_t *val)
2292 {
2293 	uint64_t count = 0;
2294 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
2295 	zap_cursor_t zc;
2296 	zap_attribute_t za;
2297 
2298 	ASSERT(dsl_pool_config_held(ds->ds_dir->dd_pool));
2299 
2300 	/*
2301 	 * There may be missing entries in ds_next_clones_obj
2302 	 * due to a bug in a previous version of the code.
2303 	 * Only trust it if it has the right number of entries.
2304 	 */
2305 	if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
2306 		VERIFY0(zap_count(mos, dsl_dataset_phys(ds)->ds_next_clones_obj,
2307 		    &count));
2308 	}
2309 	if (count != dsl_dataset_phys(ds)->ds_num_children - 1) {
2310 		return (SET_ERROR(ENOENT));
2311 	}
2312 	for (zap_cursor_init(&zc, mos,
2313 	    dsl_dataset_phys(ds)->ds_next_clones_obj);
2314 	    zap_cursor_retrieve(&zc, &za) == 0;
2315 	    zap_cursor_advance(&zc)) {
2316 		dsl_dataset_t *clone;
2317 		char buf[ZFS_MAX_DATASET_NAME_LEN];
2318 		VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
2319 		    za.za_first_integer, FTAG, &clone));
2320 		dsl_dir_name(clone->ds_dir, buf);
2321 		fnvlist_add_boolean(val, buf);
2322 		dsl_dataset_rele(clone, FTAG);
2323 	}
2324 	zap_cursor_fini(&zc);
2325 	return (0);
2326 }
2327 
2328 void
2329 get_clones_stat(dsl_dataset_t *ds, nvlist_t *nv)
2330 {
2331 	nvlist_t *propval = fnvlist_alloc();
2332 	nvlist_t *val = fnvlist_alloc();
2333 
2334 	if (get_clones_stat_impl(ds, val) == 0) {
2335 		fnvlist_add_nvlist(propval, ZPROP_VALUE, val);
2336 		fnvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_CLONES),
2337 		    propval);
2338 	}
2339 
2340 	nvlist_free(val);
2341 	nvlist_free(propval);
2342 }
2343 
2344 static char *
2345 get_receive_resume_token_impl(dsl_dataset_t *ds)
2346 {
2347 	if (!dsl_dataset_has_resume_receive_state(ds))
2348 		return (NULL);
2349 
2350 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
2351 	char *str;
2352 	void *packed;
2353 	uint8_t *compressed;
2354 	uint64_t val;
2355 	nvlist_t *token_nv = fnvlist_alloc();
2356 	size_t packed_size, compressed_size;
2357 
2358 	if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
2359 	    DS_FIELD_RESUME_FROMGUID, sizeof (val), 1, &val) == 0) {
2360 		fnvlist_add_uint64(token_nv, "fromguid", val);
2361 	}
2362 	if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
2363 	    DS_FIELD_RESUME_OBJECT, sizeof (val), 1, &val) == 0) {
2364 		fnvlist_add_uint64(token_nv, "object", val);
2365 	}
2366 	if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
2367 	    DS_FIELD_RESUME_OFFSET, sizeof (val), 1, &val) == 0) {
2368 		fnvlist_add_uint64(token_nv, "offset", val);
2369 	}
2370 	if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
2371 	    DS_FIELD_RESUME_BYTES, sizeof (val), 1, &val) == 0) {
2372 		fnvlist_add_uint64(token_nv, "bytes", val);
2373 	}
2374 	if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
2375 	    DS_FIELD_RESUME_TOGUID, sizeof (val), 1, &val) == 0) {
2376 		fnvlist_add_uint64(token_nv, "toguid", val);
2377 	}
2378 	char buf[MAXNAMELEN];
2379 	if (zap_lookup(dp->dp_meta_objset, ds->ds_object,
2380 	    DS_FIELD_RESUME_TONAME, 1, sizeof (buf), buf) == 0) {
2381 		fnvlist_add_string(token_nv, "toname", buf);
2382 	}
2383 	if (zap_contains(dp->dp_meta_objset, ds->ds_object,
2384 	    DS_FIELD_RESUME_LARGEBLOCK) == 0) {
2385 		fnvlist_add_boolean(token_nv, "largeblockok");
2386 	}
2387 	if (zap_contains(dp->dp_meta_objset, ds->ds_object,
2388 	    DS_FIELD_RESUME_EMBEDOK) == 0) {
2389 		fnvlist_add_boolean(token_nv, "embedok");
2390 	}
2391 	if (zap_contains(dp->dp_meta_objset, ds->ds_object,
2392 	    DS_FIELD_RESUME_COMPRESSOK) == 0) {
2393 		fnvlist_add_boolean(token_nv, "compressok");
2394 	}
2395 	if (zap_contains(dp->dp_meta_objset, ds->ds_object,
2396 	    DS_FIELD_RESUME_RAWOK) == 0) {
2397 		fnvlist_add_boolean(token_nv, "rawok");
2398 	}
2399 	if (dsl_dataset_feature_is_active(ds,
2400 	    SPA_FEATURE_REDACTED_DATASETS)) {
2401 		uint64_t num_redact_snaps = 0;
2402 		uint64_t *redact_snaps = NULL;
2403 		VERIFY3B(dsl_dataset_get_uint64_array_feature(ds,
2404 		    SPA_FEATURE_REDACTED_DATASETS, &num_redact_snaps,
2405 		    &redact_snaps), ==, B_TRUE);
2406 		fnvlist_add_uint64_array(token_nv, "redact_snaps",
2407 		    redact_snaps, num_redact_snaps);
2408 	}
2409 	if (zap_contains(dp->dp_meta_objset, ds->ds_object,
2410 	    DS_FIELD_RESUME_REDACT_BOOKMARK_SNAPS) == 0) {
2411 		uint64_t num_redact_snaps = 0, int_size = 0;
2412 		uint64_t *redact_snaps = NULL;
2413 		VERIFY0(zap_length(dp->dp_meta_objset, ds->ds_object,
2414 		    DS_FIELD_RESUME_REDACT_BOOKMARK_SNAPS, &int_size,
2415 		    &num_redact_snaps));
2416 		ASSERT3U(int_size, ==, sizeof (uint64_t));
2417 
2418 		redact_snaps = kmem_alloc(int_size * num_redact_snaps,
2419 		    KM_SLEEP);
2420 		VERIFY0(zap_lookup(dp->dp_meta_objset, ds->ds_object,
2421 		    DS_FIELD_RESUME_REDACT_BOOKMARK_SNAPS, int_size,
2422 		    num_redact_snaps, redact_snaps));
2423 		fnvlist_add_uint64_array(token_nv, "book_redact_snaps",
2424 		    redact_snaps, num_redact_snaps);
2425 		kmem_free(redact_snaps, int_size * num_redact_snaps);
2426 	}
2427 	packed = fnvlist_pack(token_nv, &packed_size);
2428 	fnvlist_free(token_nv);
2429 	compressed = kmem_alloc(packed_size, KM_SLEEP);
2430 
2431 	compressed_size = gzip_compress(packed, compressed,
2432 	    packed_size, packed_size, 6);
2433 
2434 	zio_cksum_t cksum;
2435 	fletcher_4_native_varsize(compressed, compressed_size, &cksum);
2436 
2437 	size_t alloc_size = compressed_size * 2 + 1;
2438 	str = kmem_alloc(alloc_size, KM_SLEEP);
2439 	for (int i = 0; i < compressed_size; i++) {
2440 		size_t offset = i * 2;
2441 		(void) snprintf(str + offset, alloc_size - offset,
2442 	    "%02x", compressed[i]);
2443 	}
2444 	str[compressed_size * 2] = '\0';
2445 	char *propval = kmem_asprintf("%u-%llx-%llx-%s",
2446 	    ZFS_SEND_RESUME_TOKEN_VERSION,
2447 	    (longlong_t)cksum.zc_word[0],
2448 	    (longlong_t)packed_size, str);
2449 	kmem_free(packed, packed_size);
2450 	kmem_free(str, alloc_size);
2451 	kmem_free(compressed, packed_size);
2452 	return (propval);
2453 }
2454 
2455 /*
2456  * Returns a string that represents the receive resume state token. It should
2457  * be freed with strfree(). NULL is returned if no resume state is present.
2458  */
2459 char *
2460 get_receive_resume_token(dsl_dataset_t *ds)
2461 {
2462 	/*
2463 	 * A failed "newfs" (e.g. full) resumable receive leaves
2464 	 * the stats set on this dataset.  Check here for the prop.
2465 	 */
2466 	char *token = get_receive_resume_token_impl(ds);
2467 	if (token != NULL)
2468 		return (token);
2469 	/*
2470 	 * A failed incremental resumable receive leaves the
2471 	 * stats set on our child named "%recv".  Check the child
2472 	 * for the prop.
2473 	 */
2474 	/* 6 extra bytes for /%recv */
2475 	char name[ZFS_MAX_DATASET_NAME_LEN + 6];
2476 	dsl_dataset_t *recv_ds;
2477 	dsl_dataset_name(ds, name);
2478 	if (strlcat(name, "/", sizeof (name)) < sizeof (name) &&
2479 	    strlcat(name, recv_clone_name, sizeof (name)) < sizeof (name) &&
2480 	    dsl_dataset_hold(ds->ds_dir->dd_pool, name, FTAG, &recv_ds) == 0) {
2481 		token = get_receive_resume_token_impl(recv_ds);
2482 		dsl_dataset_rele(recv_ds, FTAG);
2483 	}
2484 	return (token);
2485 }
2486 
2487 uint64_t
2488 dsl_get_refratio(dsl_dataset_t *ds)
2489 {
2490 	uint64_t ratio = dsl_dataset_phys(ds)->ds_compressed_bytes == 0 ? 100 :
2491 	    (dsl_dataset_phys(ds)->ds_uncompressed_bytes * 100 /
2492 	    dsl_dataset_phys(ds)->ds_compressed_bytes);
2493 	return (ratio);
2494 }
2495 
2496 uint64_t
2497 dsl_get_logicalreferenced(dsl_dataset_t *ds)
2498 {
2499 	return (dsl_dataset_phys(ds)->ds_uncompressed_bytes);
2500 }
2501 
2502 uint64_t
2503 dsl_get_compressratio(dsl_dataset_t *ds)
2504 {
2505 	if (ds->ds_is_snapshot) {
2506 		return (dsl_get_refratio(ds));
2507 	} else {
2508 		dsl_dir_t *dd = ds->ds_dir;
2509 		mutex_enter(&dd->dd_lock);
2510 		uint64_t val = dsl_dir_get_compressratio(dd);
2511 		mutex_exit(&dd->dd_lock);
2512 		return (val);
2513 	}
2514 }
2515 
2516 uint64_t
2517 dsl_get_used(dsl_dataset_t *ds)
2518 {
2519 	if (ds->ds_is_snapshot) {
2520 		return (dsl_dataset_phys(ds)->ds_unique_bytes);
2521 	} else {
2522 		dsl_dir_t *dd = ds->ds_dir;
2523 		mutex_enter(&dd->dd_lock);
2524 		uint64_t val = dsl_dir_get_used(dd);
2525 		mutex_exit(&dd->dd_lock);
2526 		return (val);
2527 	}
2528 }
2529 
2530 uint64_t
2531 dsl_get_creation(dsl_dataset_t *ds)
2532 {
2533 	return (dsl_dataset_phys(ds)->ds_creation_time);
2534 }
2535 
2536 uint64_t
2537 dsl_get_creationtxg(dsl_dataset_t *ds)
2538 {
2539 	return (dsl_dataset_phys(ds)->ds_creation_txg);
2540 }
2541 
2542 uint64_t
2543 dsl_get_refquota(dsl_dataset_t *ds)
2544 {
2545 	return (ds->ds_quota);
2546 }
2547 
2548 uint64_t
2549 dsl_get_refreservation(dsl_dataset_t *ds)
2550 {
2551 	return (ds->ds_reserved);
2552 }
2553 
2554 uint64_t
2555 dsl_get_guid(dsl_dataset_t *ds)
2556 {
2557 	return (dsl_dataset_phys(ds)->ds_guid);
2558 }
2559 
2560 uint64_t
2561 dsl_get_unique(dsl_dataset_t *ds)
2562 {
2563 	return (dsl_dataset_phys(ds)->ds_unique_bytes);
2564 }
2565 
2566 uint64_t
2567 dsl_get_objsetid(dsl_dataset_t *ds)
2568 {
2569 	return (ds->ds_object);
2570 }
2571 
2572 uint64_t
2573 dsl_get_userrefs(dsl_dataset_t *ds)
2574 {
2575 	return (ds->ds_userrefs);
2576 }
2577 
2578 uint64_t
2579 dsl_get_defer_destroy(dsl_dataset_t *ds)
2580 {
2581 	return (DS_IS_DEFER_DESTROY(ds) ? 1 : 0);
2582 }
2583 
2584 uint64_t
2585 dsl_get_referenced(dsl_dataset_t *ds)
2586 {
2587 	return (dsl_dataset_phys(ds)->ds_referenced_bytes);
2588 }
2589 
2590 uint64_t
2591 dsl_get_numclones(dsl_dataset_t *ds)
2592 {
2593 	ASSERT(ds->ds_is_snapshot);
2594 	return (dsl_dataset_phys(ds)->ds_num_children - 1);
2595 }
2596 
2597 uint64_t
2598 dsl_get_inconsistent(dsl_dataset_t *ds)
2599 {
2600 	return ((dsl_dataset_phys(ds)->ds_flags & DS_FLAG_INCONSISTENT) ?
2601 	    1 : 0);
2602 }
2603 
2604 uint64_t
2605 dsl_get_redacted(dsl_dataset_t *ds)
2606 {
2607 	return (dsl_dataset_feature_is_active(ds,
2608 	    SPA_FEATURE_REDACTED_DATASETS));
2609 }
2610 
2611 uint64_t
2612 dsl_get_available(dsl_dataset_t *ds)
2613 {
2614 	uint64_t refdbytes = dsl_get_referenced(ds);
2615 	uint64_t availbytes = dsl_dir_space_available(ds->ds_dir,
2616 	    NULL, 0, TRUE);
2617 	if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes) {
2618 		availbytes +=
2619 		    ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes;
2620 	}
2621 	if (ds->ds_quota != 0) {
2622 		/*
2623 		 * Adjust available bytes according to refquota
2624 		 */
2625 		if (refdbytes < ds->ds_quota) {
2626 			availbytes = MIN(availbytes,
2627 			    ds->ds_quota - refdbytes);
2628 		} else {
2629 			availbytes = 0;
2630 		}
2631 	}
2632 	return (availbytes);
2633 }
2634 
2635 int
2636 dsl_get_written(dsl_dataset_t *ds, uint64_t *written)
2637 {
2638 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
2639 	dsl_dataset_t *prev;
2640 	int err = dsl_dataset_hold_obj(dp,
2641 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
2642 	if (err == 0) {
2643 		uint64_t comp, uncomp;
2644 		err = dsl_dataset_space_written(prev, ds, written,
2645 		    &comp, &uncomp);
2646 		dsl_dataset_rele(prev, FTAG);
2647 	}
2648 	return (err);
2649 }
2650 
2651 /*
2652  * 'snap' should be a buffer of size ZFS_MAX_DATASET_NAME_LEN.
2653  */
2654 int
2655 dsl_get_prev_snap(dsl_dataset_t *ds, char *snap)
2656 {
2657 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
2658 	if (ds->ds_prev != NULL && ds->ds_prev != dp->dp_origin_snap) {
2659 		dsl_dataset_name(ds->ds_prev, snap);
2660 		return (0);
2661 	} else {
2662 		return (SET_ERROR(ENOENT));
2663 	}
2664 }
2665 
2666 void
2667 dsl_get_redact_snaps(dsl_dataset_t *ds, nvlist_t *propval)
2668 {
2669 	uint64_t nsnaps;
2670 	uint64_t *snaps;
2671 	if (dsl_dataset_get_uint64_array_feature(ds,
2672 	    SPA_FEATURE_REDACTED_DATASETS, &nsnaps, &snaps)) {
2673 		fnvlist_add_uint64_array(propval, ZPROP_VALUE, snaps,
2674 		    nsnaps);
2675 	}
2676 }
2677 
2678 /*
2679  * Returns the mountpoint property and source for the given dataset in the value
2680  * and source buffers. The value buffer must be at least as large as MAXPATHLEN
2681  * and the source buffer as least as large a ZFS_MAX_DATASET_NAME_LEN.
2682  * Returns 0 on success and an error on failure.
2683  */
2684 int
2685 dsl_get_mountpoint(dsl_dataset_t *ds, const char *dsname, char *value,
2686     char *source)
2687 {
2688 	int error;
2689 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
2690 
2691 	/* Retrieve the mountpoint value stored in the zap object */
2692 	error = dsl_prop_get_ds(ds, zfs_prop_to_name(ZFS_PROP_MOUNTPOINT), 1,
2693 	    ZAP_MAXVALUELEN, value, source);
2694 	if (error != 0) {
2695 		return (error);
2696 	}
2697 
2698 	/*
2699 	 * Process the dsname and source to find the full mountpoint string.
2700 	 * Can be skipped for 'legacy' or 'none'.
2701 	 */
2702 	if (value[0] == '/') {
2703 		char *buf = kmem_alloc(ZAP_MAXVALUELEN, KM_SLEEP);
2704 		char *root = buf;
2705 		const char *relpath;
2706 
2707 		/*
2708 		 * If we inherit the mountpoint, even from a dataset
2709 		 * with a received value, the source will be the path of
2710 		 * the dataset we inherit from. If source is
2711 		 * ZPROP_SOURCE_VAL_RECVD, the received value is not
2712 		 * inherited.
2713 		 */
2714 		if (strcmp(source, ZPROP_SOURCE_VAL_RECVD) == 0) {
2715 			relpath = "";
2716 		} else {
2717 			ASSERT0(strncmp(dsname, source, strlen(source)));
2718 			relpath = dsname + strlen(source);
2719 			if (relpath[0] == '/')
2720 				relpath++;
2721 		}
2722 
2723 		spa_altroot(dp->dp_spa, root, ZAP_MAXVALUELEN);
2724 
2725 		/*
2726 		 * Special case an alternate root of '/'. This will
2727 		 * avoid having multiple leading slashes in the
2728 		 * mountpoint path.
2729 		 */
2730 		if (strcmp(root, "/") == 0)
2731 			root++;
2732 
2733 		/*
2734 		 * If the mountpoint is '/' then skip over this
2735 		 * if we are obtaining either an alternate root or
2736 		 * an inherited mountpoint.
2737 		 */
2738 		char *mnt = value;
2739 		if (value[1] == '\0' && (root[0] != '\0' ||
2740 		    relpath[0] != '\0'))
2741 			mnt = value + 1;
2742 
2743 		mnt = kmem_strdup(mnt);
2744 
2745 		if (relpath[0] == '\0') {
2746 			(void) snprintf(value, ZAP_MAXVALUELEN, "%s%s",
2747 			    root, mnt);
2748 		} else {
2749 			(void) snprintf(value, ZAP_MAXVALUELEN, "%s%s%s%s",
2750 			    root, mnt, relpath[0] == '@' ? "" : "/",
2751 			    relpath);
2752 		}
2753 		kmem_free(buf, ZAP_MAXVALUELEN);
2754 		kmem_strfree(mnt);
2755 	}
2756 
2757 	return (0);
2758 }
2759 
2760 void
2761 dsl_dataset_stats(dsl_dataset_t *ds, nvlist_t *nv)
2762 {
2763 	dsl_pool_t *dp __maybe_unused = ds->ds_dir->dd_pool;
2764 
2765 	ASSERT(dsl_pool_config_held(dp));
2766 
2767 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRATIO,
2768 	    dsl_get_refratio(ds));
2769 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_LOGICALREFERENCED,
2770 	    dsl_get_logicalreferenced(ds));
2771 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_COMPRESSRATIO,
2772 	    dsl_get_compressratio(ds));
2773 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USED,
2774 	    dsl_get_used(ds));
2775 
2776 	if (ds->ds_is_snapshot) {
2777 		get_clones_stat(ds, nv);
2778 	} else {
2779 		char buf[ZFS_MAX_DATASET_NAME_LEN];
2780 		if (dsl_get_prev_snap(ds, buf) == 0)
2781 			dsl_prop_nvlist_add_string(nv, ZFS_PROP_PREV_SNAP,
2782 			    buf);
2783 		dsl_dir_stats(ds->ds_dir, nv);
2784 	}
2785 
2786 	nvlist_t *propval = fnvlist_alloc();
2787 	dsl_get_redact_snaps(ds, propval);
2788 	fnvlist_add_nvlist(nv, zfs_prop_to_name(ZFS_PROP_REDACT_SNAPS),
2789 	    propval);
2790 	nvlist_free(propval);
2791 
2792 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_AVAILABLE,
2793 	    dsl_get_available(ds));
2794 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFERENCED,
2795 	    dsl_get_referenced(ds));
2796 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATION,
2797 	    dsl_get_creation(ds));
2798 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_CREATETXG,
2799 	    dsl_get_creationtxg(ds));
2800 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFQUOTA,
2801 	    dsl_get_refquota(ds));
2802 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_REFRESERVATION,
2803 	    dsl_get_refreservation(ds));
2804 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_GUID,
2805 	    dsl_get_guid(ds));
2806 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_UNIQUE,
2807 	    dsl_get_unique(ds));
2808 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_OBJSETID,
2809 	    dsl_get_objsetid(ds));
2810 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_USERREFS,
2811 	    dsl_get_userrefs(ds));
2812 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_DEFER_DESTROY,
2813 	    dsl_get_defer_destroy(ds));
2814 	dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_SNAPSHOTS_CHANGED,
2815 	    dsl_dir_snap_cmtime(ds->ds_dir).tv_sec);
2816 	dsl_dataset_crypt_stats(ds, nv);
2817 
2818 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
2819 		uint64_t written;
2820 		if (dsl_get_written(ds, &written) == 0) {
2821 			dsl_prop_nvlist_add_uint64(nv, ZFS_PROP_WRITTEN,
2822 			    written);
2823 		}
2824 	}
2825 
2826 	if (!dsl_dataset_is_snapshot(ds)) {
2827 		char *token = get_receive_resume_token(ds);
2828 		if (token != NULL) {
2829 			dsl_prop_nvlist_add_string(nv,
2830 			    ZFS_PROP_RECEIVE_RESUME_TOKEN, token);
2831 			kmem_strfree(token);
2832 		}
2833 	}
2834 }
2835 
2836 void
2837 dsl_dataset_fast_stat(dsl_dataset_t *ds, dmu_objset_stats_t *stat)
2838 {
2839 	dsl_pool_t *dp __maybe_unused = ds->ds_dir->dd_pool;
2840 	ASSERT(dsl_pool_config_held(dp));
2841 
2842 	stat->dds_creation_txg = dsl_get_creationtxg(ds);
2843 	stat->dds_inconsistent = dsl_get_inconsistent(ds);
2844 	stat->dds_guid = dsl_get_guid(ds);
2845 	stat->dds_redacted = dsl_get_redacted(ds);
2846 	stat->dds_origin[0] = '\0';
2847 	if (ds->ds_is_snapshot) {
2848 		stat->dds_is_snapshot = B_TRUE;
2849 		stat->dds_num_clones = dsl_get_numclones(ds);
2850 	} else {
2851 		stat->dds_is_snapshot = B_FALSE;
2852 		stat->dds_num_clones = 0;
2853 
2854 		if (dsl_dir_is_clone(ds->ds_dir)) {
2855 			dsl_dir_get_origin(ds->ds_dir, stat->dds_origin);
2856 		}
2857 	}
2858 }
2859 
2860 uint64_t
2861 dsl_dataset_fsid_guid(dsl_dataset_t *ds)
2862 {
2863 	return (ds->ds_fsid_guid);
2864 }
2865 
2866 void
2867 dsl_dataset_space(dsl_dataset_t *ds,
2868     uint64_t *refdbytesp, uint64_t *availbytesp,
2869     uint64_t *usedobjsp, uint64_t *availobjsp)
2870 {
2871 	*refdbytesp = dsl_dataset_phys(ds)->ds_referenced_bytes;
2872 	*availbytesp = dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE);
2873 	if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes)
2874 		*availbytesp +=
2875 		    ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes;
2876 	if (ds->ds_quota != 0) {
2877 		/*
2878 		 * Adjust available bytes according to refquota
2879 		 */
2880 		if (*refdbytesp < ds->ds_quota)
2881 			*availbytesp = MIN(*availbytesp,
2882 			    ds->ds_quota - *refdbytesp);
2883 		else
2884 			*availbytesp = 0;
2885 	}
2886 	rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
2887 	*usedobjsp = BP_GET_FILL(&dsl_dataset_phys(ds)->ds_bp);
2888 	rrw_exit(&ds->ds_bp_rwlock, FTAG);
2889 	*availobjsp = DN_MAX_OBJECT - *usedobjsp;
2890 }
2891 
2892 boolean_t
2893 dsl_dataset_modified_since_snap(dsl_dataset_t *ds, dsl_dataset_t *snap)
2894 {
2895 	dsl_pool_t *dp __maybe_unused = ds->ds_dir->dd_pool;
2896 	uint64_t birth;
2897 
2898 	ASSERT(dsl_pool_config_held(dp));
2899 	if (snap == NULL)
2900 		return (B_FALSE);
2901 	rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
2902 	birth = dsl_dataset_get_blkptr(ds)->blk_birth;
2903 	rrw_exit(&ds->ds_bp_rwlock, FTAG);
2904 	if (birth > dsl_dataset_phys(snap)->ds_creation_txg) {
2905 		objset_t *os, *os_snap;
2906 		/*
2907 		 * It may be that only the ZIL differs, because it was
2908 		 * reset in the head.  Don't count that as being
2909 		 * modified.
2910 		 */
2911 		if (dmu_objset_from_ds(ds, &os) != 0)
2912 			return (B_TRUE);
2913 		if (dmu_objset_from_ds(snap, &os_snap) != 0)
2914 			return (B_TRUE);
2915 		return (memcmp(&os->os_phys->os_meta_dnode,
2916 		    &os_snap->os_phys->os_meta_dnode,
2917 		    sizeof (os->os_phys->os_meta_dnode)) != 0);
2918 	}
2919 	return (B_FALSE);
2920 }
2921 
2922 static int
2923 dsl_dataset_rename_snapshot_check_impl(dsl_pool_t *dp,
2924     dsl_dataset_t *hds, void *arg)
2925 {
2926 	(void) dp;
2927 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2928 	int error;
2929 	uint64_t val;
2930 
2931 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
2932 	if (error != 0) {
2933 		/* ignore nonexistent snapshots */
2934 		return (error == ENOENT ? 0 : error);
2935 	}
2936 
2937 	/* new name should not exist */
2938 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_newsnapname, &val);
2939 	if (error == 0)
2940 		error = SET_ERROR(EEXIST);
2941 	else if (error == ENOENT)
2942 		error = 0;
2943 
2944 	/* dataset name + 1 for the "@" + the new snapshot name must fit */
2945 	if (dsl_dir_namelen(hds->ds_dir) + 1 +
2946 	    strlen(ddrsa->ddrsa_newsnapname) >= ZFS_MAX_DATASET_NAME_LEN)
2947 		error = SET_ERROR(ENAMETOOLONG);
2948 
2949 	return (error);
2950 }
2951 
2952 int
2953 dsl_dataset_rename_snapshot_check(void *arg, dmu_tx_t *tx)
2954 {
2955 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2956 	dsl_pool_t *dp = dmu_tx_pool(tx);
2957 	dsl_dataset_t *hds;
2958 	int error;
2959 
2960 	error = dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds);
2961 	if (error != 0)
2962 		return (error);
2963 
2964 	if (ddrsa->ddrsa_recursive) {
2965 		error = dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
2966 		    dsl_dataset_rename_snapshot_check_impl, ddrsa,
2967 		    DS_FIND_CHILDREN);
2968 	} else {
2969 		error = dsl_dataset_rename_snapshot_check_impl(dp, hds, ddrsa);
2970 	}
2971 	dsl_dataset_rele(hds, FTAG);
2972 	return (error);
2973 }
2974 
2975 static int
2976 dsl_dataset_rename_snapshot_sync_impl(dsl_pool_t *dp,
2977     dsl_dataset_t *hds, void *arg)
2978 {
2979 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
2980 	dsl_dataset_t *ds;
2981 	uint64_t val;
2982 	dmu_tx_t *tx = ddrsa->ddrsa_tx;
2983 	int error;
2984 
2985 	error = dsl_dataset_snap_lookup(hds, ddrsa->ddrsa_oldsnapname, &val);
2986 	ASSERT(error == 0 || error == ENOENT);
2987 	if (error == ENOENT) {
2988 		/* ignore nonexistent snapshots */
2989 		return (0);
2990 	}
2991 
2992 	VERIFY0(dsl_dataset_hold_obj(dp, val, FTAG, &ds));
2993 
2994 	/* log before we change the name */
2995 	spa_history_log_internal_ds(ds, "rename", tx,
2996 	    "-> @%s", ddrsa->ddrsa_newsnapname);
2997 
2998 	VERIFY0(dsl_dataset_snap_remove(hds, ddrsa->ddrsa_oldsnapname, tx,
2999 	    B_FALSE));
3000 	mutex_enter(&ds->ds_lock);
3001 	(void) strlcpy(ds->ds_snapname, ddrsa->ddrsa_newsnapname,
3002 	    sizeof (ds->ds_snapname));
3003 	mutex_exit(&ds->ds_lock);
3004 	VERIFY0(zap_add(dp->dp_meta_objset,
3005 	    dsl_dataset_phys(hds)->ds_snapnames_zapobj,
3006 	    ds->ds_snapname, 8, 1, &ds->ds_object, tx));
3007 	zvol_rename_minors(dp->dp_spa, ddrsa->ddrsa_oldsnapname,
3008 	    ddrsa->ddrsa_newsnapname, B_TRUE);
3009 
3010 	dsl_dataset_rele(ds, FTAG);
3011 	return (0);
3012 }
3013 
3014 void
3015 dsl_dataset_rename_snapshot_sync(void *arg, dmu_tx_t *tx)
3016 {
3017 	dsl_dataset_rename_snapshot_arg_t *ddrsa = arg;
3018 	dsl_pool_t *dp = dmu_tx_pool(tx);
3019 	dsl_dataset_t *hds = NULL;
3020 
3021 	VERIFY0(dsl_dataset_hold(dp, ddrsa->ddrsa_fsname, FTAG, &hds));
3022 	ddrsa->ddrsa_tx = tx;
3023 	if (ddrsa->ddrsa_recursive) {
3024 		VERIFY0(dmu_objset_find_dp(dp, hds->ds_dir->dd_object,
3025 		    dsl_dataset_rename_snapshot_sync_impl, ddrsa,
3026 		    DS_FIND_CHILDREN));
3027 	} else {
3028 		VERIFY0(dsl_dataset_rename_snapshot_sync_impl(dp, hds, ddrsa));
3029 	}
3030 	dsl_dataset_rele(hds, FTAG);
3031 }
3032 
3033 int
3034 dsl_dataset_rename_snapshot(const char *fsname,
3035     const char *oldsnapname, const char *newsnapname, boolean_t recursive)
3036 {
3037 	dsl_dataset_rename_snapshot_arg_t ddrsa;
3038 
3039 	ddrsa.ddrsa_fsname = fsname;
3040 	ddrsa.ddrsa_oldsnapname = oldsnapname;
3041 	ddrsa.ddrsa_newsnapname = newsnapname;
3042 	ddrsa.ddrsa_recursive = recursive;
3043 
3044 	return (dsl_sync_task(fsname, dsl_dataset_rename_snapshot_check,
3045 	    dsl_dataset_rename_snapshot_sync, &ddrsa,
3046 	    1, ZFS_SPACE_CHECK_RESERVED));
3047 }
3048 
3049 /*
3050  * If we're doing an ownership handoff, we need to make sure that there is
3051  * only one long hold on the dataset.  We're not allowed to change anything here
3052  * so we don't permanently release the long hold or regular hold here.  We want
3053  * to do this only when syncing to avoid the dataset unexpectedly going away
3054  * when we release the long hold.
3055  */
3056 static int
3057 dsl_dataset_handoff_check(dsl_dataset_t *ds, void *owner, dmu_tx_t *tx)
3058 {
3059 	boolean_t held = B_FALSE;
3060 
3061 	if (!dmu_tx_is_syncing(tx))
3062 		return (0);
3063 
3064 	dsl_dir_t *dd = ds->ds_dir;
3065 	mutex_enter(&dd->dd_activity_lock);
3066 	uint64_t holds = zfs_refcount_count(&ds->ds_longholds) -
3067 	    (owner != NULL ? 1 : 0);
3068 	/*
3069 	 * The value of dd_activity_waiters can chance as soon as we drop the
3070 	 * lock, but we're fine with that; new waiters coming in or old
3071 	 * waiters leaving doesn't cause problems, since we're going to cancel
3072 	 * waiters later anyway. The goal of this check is to verify that no
3073 	 * non-waiters have long-holds, and all new long-holds will be
3074 	 * prevented because we're holding the pool config as writer.
3075 	 */
3076 	if (holds != dd->dd_activity_waiters)
3077 		held = B_TRUE;
3078 	mutex_exit(&dd->dd_activity_lock);
3079 
3080 	if (held)
3081 		return (SET_ERROR(EBUSY));
3082 
3083 	return (0);
3084 }
3085 
3086 int
3087 dsl_dataset_rollback_check(void *arg, dmu_tx_t *tx)
3088 {
3089 	dsl_dataset_rollback_arg_t *ddra = arg;
3090 	dsl_pool_t *dp = dmu_tx_pool(tx);
3091 	dsl_dataset_t *ds;
3092 	int64_t unused_refres_delta;
3093 	int error;
3094 
3095 	error = dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds);
3096 	if (error != 0)
3097 		return (error);
3098 
3099 	/* must not be a snapshot */
3100 	if (ds->ds_is_snapshot) {
3101 		dsl_dataset_rele(ds, FTAG);
3102 		return (SET_ERROR(EINVAL));
3103 	}
3104 
3105 	/* must have a most recent snapshot */
3106 	if (dsl_dataset_phys(ds)->ds_prev_snap_txg < TXG_INITIAL) {
3107 		dsl_dataset_rele(ds, FTAG);
3108 		return (SET_ERROR(ESRCH));
3109 	}
3110 
3111 	/*
3112 	 * No rollback to a snapshot created in the current txg, because
3113 	 * the rollback may dirty the dataset and create blocks that are
3114 	 * not reachable from the rootbp while having a birth txg that
3115 	 * falls into the snapshot's range.
3116 	 */
3117 	if (dmu_tx_is_syncing(tx) &&
3118 	    dsl_dataset_phys(ds)->ds_prev_snap_txg >= tx->tx_txg) {
3119 		dsl_dataset_rele(ds, FTAG);
3120 		return (SET_ERROR(EAGAIN));
3121 	}
3122 
3123 	/*
3124 	 * If the expected target snapshot is specified, then check that
3125 	 * the latest snapshot is it.
3126 	 */
3127 	if (ddra->ddra_tosnap != NULL) {
3128 		dsl_dataset_t *snapds;
3129 
3130 		/* Check if the target snapshot exists at all. */
3131 		error = dsl_dataset_hold(dp, ddra->ddra_tosnap, FTAG, &snapds);
3132 		if (error != 0) {
3133 			/*
3134 			 * ESRCH is used to signal that the target snapshot does
3135 			 * not exist, while ENOENT is used to report that
3136 			 * the rolled back dataset does not exist.
3137 			 * ESRCH is also used to cover other cases where the
3138 			 * target snapshot is not related to the dataset being
3139 			 * rolled back such as being in a different pool.
3140 			 */
3141 			if (error == ENOENT || error == EXDEV)
3142 				error = SET_ERROR(ESRCH);
3143 			dsl_dataset_rele(ds, FTAG);
3144 			return (error);
3145 		}
3146 		ASSERT(snapds->ds_is_snapshot);
3147 
3148 		/* Check if the snapshot is the latest snapshot indeed. */
3149 		if (snapds != ds->ds_prev) {
3150 			/*
3151 			 * Distinguish between the case where the only problem
3152 			 * is intervening snapshots (EEXIST) vs the snapshot
3153 			 * not being a valid target for rollback (ESRCH).
3154 			 */
3155 			if (snapds->ds_dir == ds->ds_dir ||
3156 			    (dsl_dir_is_clone(ds->ds_dir) &&
3157 			    dsl_dir_phys(ds->ds_dir)->dd_origin_obj ==
3158 			    snapds->ds_object)) {
3159 				error = SET_ERROR(EEXIST);
3160 			} else {
3161 				error = SET_ERROR(ESRCH);
3162 			}
3163 			dsl_dataset_rele(snapds, FTAG);
3164 			dsl_dataset_rele(ds, FTAG);
3165 			return (error);
3166 		}
3167 		dsl_dataset_rele(snapds, FTAG);
3168 	}
3169 
3170 	/* must not have any bookmarks after the most recent snapshot */
3171 	if (dsl_bookmark_latest_txg(ds) >
3172 	    dsl_dataset_phys(ds)->ds_prev_snap_txg) {
3173 		dsl_dataset_rele(ds, FTAG);
3174 		return (SET_ERROR(EEXIST));
3175 	}
3176 
3177 	error = dsl_dataset_handoff_check(ds, ddra->ddra_owner, tx);
3178 	if (error != 0) {
3179 		dsl_dataset_rele(ds, FTAG);
3180 		return (error);
3181 	}
3182 
3183 	/*
3184 	 * Check if the snap we are rolling back to uses more than
3185 	 * the refquota.
3186 	 */
3187 	if (ds->ds_quota != 0 &&
3188 	    dsl_dataset_phys(ds->ds_prev)->ds_referenced_bytes > ds->ds_quota) {
3189 		dsl_dataset_rele(ds, FTAG);
3190 		return (SET_ERROR(EDQUOT));
3191 	}
3192 
3193 	/*
3194 	 * When we do the clone swap, we will temporarily use more space
3195 	 * due to the refreservation (the head will no longer have any
3196 	 * unique space, so the entire amount of the refreservation will need
3197 	 * to be free).  We will immediately destroy the clone, freeing
3198 	 * this space, but the freeing happens over many txg's.
3199 	 */
3200 	unused_refres_delta = (int64_t)MIN(ds->ds_reserved,
3201 	    dsl_dataset_phys(ds)->ds_unique_bytes);
3202 
3203 	if (unused_refres_delta > 0 &&
3204 	    unused_refres_delta >
3205 	    dsl_dir_space_available(ds->ds_dir, NULL, 0, TRUE)) {
3206 		dsl_dataset_rele(ds, FTAG);
3207 		return (SET_ERROR(ENOSPC));
3208 	}
3209 
3210 	dsl_dataset_rele(ds, FTAG);
3211 	return (0);
3212 }
3213 
3214 void
3215 dsl_dataset_rollback_sync(void *arg, dmu_tx_t *tx)
3216 {
3217 	dsl_dataset_rollback_arg_t *ddra = arg;
3218 	dsl_pool_t *dp = dmu_tx_pool(tx);
3219 	dsl_dataset_t *ds, *clone;
3220 	uint64_t cloneobj;
3221 	char namebuf[ZFS_MAX_DATASET_NAME_LEN];
3222 
3223 	VERIFY0(dsl_dataset_hold(dp, ddra->ddra_fsname, FTAG, &ds));
3224 
3225 	dsl_dataset_name(ds->ds_prev, namebuf);
3226 	fnvlist_add_string(ddra->ddra_result, "target", namebuf);
3227 
3228 	cloneobj = dsl_dataset_create_sync(ds->ds_dir, "%rollback",
3229 	    ds->ds_prev, DS_CREATE_FLAG_NODIRTY, kcred, NULL, tx);
3230 
3231 	VERIFY0(dsl_dataset_hold_obj(dp, cloneobj, FTAG, &clone));
3232 
3233 	dsl_dataset_clone_swap_sync_impl(clone, ds, tx);
3234 	dsl_dataset_zero_zil(ds, tx);
3235 
3236 	dsl_destroy_head_sync_impl(clone, tx);
3237 
3238 	dsl_dataset_rele(clone, FTAG);
3239 	dsl_dataset_rele(ds, FTAG);
3240 }
3241 
3242 /*
3243  * Rolls back the given filesystem or volume to the most recent snapshot.
3244  * The name of the most recent snapshot will be returned under key "target"
3245  * in the result nvlist.
3246  *
3247  * If owner != NULL:
3248  * - The existing dataset MUST be owned by the specified owner at entry
3249  * - Upon return, dataset will still be held by the same owner, whether we
3250  *   succeed or not.
3251  *
3252  * This mode is required any time the existing filesystem is mounted.  See
3253  * notes above zfs_suspend_fs() for further details.
3254  */
3255 int
3256 dsl_dataset_rollback(const char *fsname, const char *tosnap, void *owner,
3257     nvlist_t *result)
3258 {
3259 	dsl_dataset_rollback_arg_t ddra;
3260 
3261 	ddra.ddra_fsname = fsname;
3262 	ddra.ddra_tosnap = tosnap;
3263 	ddra.ddra_owner = owner;
3264 	ddra.ddra_result = result;
3265 
3266 	return (dsl_sync_task(fsname, dsl_dataset_rollback_check,
3267 	    dsl_dataset_rollback_sync, &ddra,
3268 	    1, ZFS_SPACE_CHECK_RESERVED));
3269 }
3270 
3271 struct promotenode {
3272 	list_node_t link;
3273 	dsl_dataset_t *ds;
3274 };
3275 
3276 static int snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep);
3277 static int promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp,
3278     const void *tag);
3279 static void promote_rele(dsl_dataset_promote_arg_t *ddpa, const void *tag);
3280 
3281 int
3282 dsl_dataset_promote_check(void *arg, dmu_tx_t *tx)
3283 {
3284 	dsl_dataset_promote_arg_t *ddpa = arg;
3285 	dsl_pool_t *dp = dmu_tx_pool(tx);
3286 	dsl_dataset_t *hds;
3287 	struct promotenode *snap;
3288 	int err;
3289 	uint64_t unused;
3290 	uint64_t ss_mv_cnt;
3291 	size_t max_snap_len;
3292 	boolean_t conflicting_snaps;
3293 
3294 	err = promote_hold(ddpa, dp, FTAG);
3295 	if (err != 0)
3296 		return (err);
3297 
3298 	hds = ddpa->ddpa_clone;
3299 	max_snap_len = MAXNAMELEN - strlen(ddpa->ddpa_clonename) - 1;
3300 
3301 	if (dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE) {
3302 		promote_rele(ddpa, FTAG);
3303 		return (SET_ERROR(EXDEV));
3304 	}
3305 
3306 	snap = list_head(&ddpa->shared_snaps);
3307 	if (snap == NULL) {
3308 		err = SET_ERROR(ENOENT);
3309 		goto out;
3310 	}
3311 	dsl_dataset_t *const origin_ds = snap->ds;
3312 
3313 	/*
3314 	 * Encrypted clones share a DSL Crypto Key with their origin's dsl dir.
3315 	 * When doing a promote we must make sure the encryption root for
3316 	 * both the target and the target's origin does not change to avoid
3317 	 * needing to rewrap encryption keys
3318 	 */
3319 	err = dsl_dataset_promote_crypt_check(hds->ds_dir, origin_ds->ds_dir);
3320 	if (err != 0)
3321 		goto out;
3322 
3323 	/*
3324 	 * Compute and check the amount of space to transfer.  Since this is
3325 	 * so expensive, don't do the preliminary check.
3326 	 */
3327 	if (!dmu_tx_is_syncing(tx)) {
3328 		promote_rele(ddpa, FTAG);
3329 		return (0);
3330 	}
3331 
3332 	/* compute origin's new unique space */
3333 	snap = list_tail(&ddpa->clone_snaps);
3334 	ASSERT(snap != NULL);
3335 	ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
3336 	    origin_ds->ds_object);
3337 	dsl_deadlist_space_range(&snap->ds->ds_deadlist,
3338 	    dsl_dataset_phys(origin_ds)->ds_prev_snap_txg, UINT64_MAX,
3339 	    &ddpa->unique, &unused, &unused);
3340 
3341 	/*
3342 	 * Walk the snapshots that we are moving
3343 	 *
3344 	 * Compute space to transfer.  Consider the incremental changes
3345 	 * to used by each snapshot:
3346 	 * (my used) = (prev's used) + (blocks born) - (blocks killed)
3347 	 * So each snapshot gave birth to:
3348 	 * (blocks born) = (my used) - (prev's used) + (blocks killed)
3349 	 * So a sequence would look like:
3350 	 * (uN - u(N-1) + kN) + ... + (u1 - u0 + k1) + (u0 - 0 + k0)
3351 	 * Which simplifies to:
3352 	 * uN + kN + kN-1 + ... + k1 + k0
3353 	 * Note however, if we stop before we reach the ORIGIN we get:
3354 	 * uN + kN + kN-1 + ... + kM - uM-1
3355 	 */
3356 	conflicting_snaps = B_FALSE;
3357 	ss_mv_cnt = 0;
3358 	ddpa->used = dsl_dataset_phys(origin_ds)->ds_referenced_bytes;
3359 	ddpa->comp = dsl_dataset_phys(origin_ds)->ds_compressed_bytes;
3360 	ddpa->uncomp = dsl_dataset_phys(origin_ds)->ds_uncompressed_bytes;
3361 	for (snap = list_head(&ddpa->shared_snaps); snap;
3362 	    snap = list_next(&ddpa->shared_snaps, snap)) {
3363 		uint64_t val, dlused, dlcomp, dluncomp;
3364 		dsl_dataset_t *ds = snap->ds;
3365 
3366 		ss_mv_cnt++;
3367 
3368 		/*
3369 		 * If there are long holds, we won't be able to evict
3370 		 * the objset.
3371 		 */
3372 		if (dsl_dataset_long_held(ds)) {
3373 			err = SET_ERROR(EBUSY);
3374 			goto out;
3375 		}
3376 
3377 		/* Check that the snapshot name does not conflict */
3378 		VERIFY0(dsl_dataset_get_snapname(ds));
3379 		if (strlen(ds->ds_snapname) >= max_snap_len) {
3380 			err = SET_ERROR(ENAMETOOLONG);
3381 			goto out;
3382 		}
3383 		err = dsl_dataset_snap_lookup(hds, ds->ds_snapname, &val);
3384 		if (err == 0) {
3385 			fnvlist_add_boolean(ddpa->err_ds,
3386 			    snap->ds->ds_snapname);
3387 			conflicting_snaps = B_TRUE;
3388 		} else if (err != ENOENT) {
3389 			goto out;
3390 		}
3391 
3392 		/* The very first snapshot does not have a deadlist */
3393 		if (dsl_dataset_phys(ds)->ds_prev_snap_obj == 0)
3394 			continue;
3395 
3396 		dsl_deadlist_space(&ds->ds_deadlist,
3397 		    &dlused, &dlcomp, &dluncomp);
3398 		ddpa->used += dlused;
3399 		ddpa->comp += dlcomp;
3400 		ddpa->uncomp += dluncomp;
3401 	}
3402 
3403 	/*
3404 	 * Check that bookmarks that are being transferred don't have
3405 	 * name conflicts.
3406 	 */
3407 	for (dsl_bookmark_node_t *dbn = avl_first(&origin_ds->ds_bookmarks);
3408 	    dbn != NULL && dbn->dbn_phys.zbm_creation_txg <=
3409 	    dsl_dataset_phys(origin_ds)->ds_creation_txg;
3410 	    dbn = AVL_NEXT(&origin_ds->ds_bookmarks, dbn)) {
3411 		if (strlen(dbn->dbn_name) >= max_snap_len) {
3412 			err = SET_ERROR(ENAMETOOLONG);
3413 			goto out;
3414 		}
3415 		zfs_bookmark_phys_t bm;
3416 		err = dsl_bookmark_lookup_impl(ddpa->ddpa_clone,
3417 		    dbn->dbn_name, &bm);
3418 
3419 		if (err == 0) {
3420 			fnvlist_add_boolean(ddpa->err_ds, dbn->dbn_name);
3421 			conflicting_snaps = B_TRUE;
3422 		} else if (err == ESRCH) {
3423 			err = 0;
3424 		} else if (err != 0) {
3425 			goto out;
3426 		}
3427 	}
3428 
3429 	/*
3430 	 * In order to return the full list of conflicting snapshots, we check
3431 	 * whether there was a conflict after traversing all of them.
3432 	 */
3433 	if (conflicting_snaps) {
3434 		err = SET_ERROR(EEXIST);
3435 		goto out;
3436 	}
3437 
3438 	/*
3439 	 * If we are a clone of a clone then we never reached ORIGIN,
3440 	 * so we need to subtract out the clone origin's used space.
3441 	 */
3442 	if (ddpa->origin_origin) {
3443 		ddpa->used -=
3444 		    dsl_dataset_phys(ddpa->origin_origin)->ds_referenced_bytes;
3445 		ddpa->comp -=
3446 		    dsl_dataset_phys(ddpa->origin_origin)->ds_compressed_bytes;
3447 		ddpa->uncomp -=
3448 		    dsl_dataset_phys(ddpa->origin_origin)->
3449 		    ds_uncompressed_bytes;
3450 	}
3451 
3452 	/* Check that there is enough space and limit headroom here */
3453 	err = dsl_dir_transfer_possible(origin_ds->ds_dir, hds->ds_dir,
3454 	    0, ss_mv_cnt, ddpa->used, ddpa->cr, ddpa->proc);
3455 	if (err != 0)
3456 		goto out;
3457 
3458 	/*
3459 	 * Compute the amounts of space that will be used by snapshots
3460 	 * after the promotion (for both origin and clone).  For each,
3461 	 * it is the amount of space that will be on all of their
3462 	 * deadlists (that was not born before their new origin).
3463 	 */
3464 	if (dsl_dir_phys(hds->ds_dir)->dd_flags & DD_FLAG_USED_BREAKDOWN) {
3465 		uint64_t space;
3466 
3467 		/*
3468 		 * Note, typically this will not be a clone of a clone,
3469 		 * so dd_origin_txg will be < TXG_INITIAL, so
3470 		 * these snaplist_space() -> dsl_deadlist_space_range()
3471 		 * calls will be fast because they do not have to
3472 		 * iterate over all bps.
3473 		 */
3474 		snap = list_head(&ddpa->origin_snaps);
3475 		if (snap == NULL) {
3476 			err = SET_ERROR(ENOENT);
3477 			goto out;
3478 		}
3479 		err = snaplist_space(&ddpa->shared_snaps,
3480 		    snap->ds->ds_dir->dd_origin_txg, &ddpa->cloneusedsnap);
3481 		if (err != 0)
3482 			goto out;
3483 
3484 		err = snaplist_space(&ddpa->clone_snaps,
3485 		    snap->ds->ds_dir->dd_origin_txg, &space);
3486 		if (err != 0)
3487 			goto out;
3488 		ddpa->cloneusedsnap += space;
3489 	}
3490 	if (dsl_dir_phys(origin_ds->ds_dir)->dd_flags &
3491 	    DD_FLAG_USED_BREAKDOWN) {
3492 		err = snaplist_space(&ddpa->origin_snaps,
3493 		    dsl_dataset_phys(origin_ds)->ds_creation_txg,
3494 		    &ddpa->originusedsnap);
3495 		if (err != 0)
3496 			goto out;
3497 	}
3498 
3499 out:
3500 	promote_rele(ddpa, FTAG);
3501 	return (err);
3502 }
3503 
3504 void
3505 dsl_dataset_promote_sync(void *arg, dmu_tx_t *tx)
3506 {
3507 	dsl_dataset_promote_arg_t *ddpa = arg;
3508 	dsl_pool_t *dp = dmu_tx_pool(tx);
3509 	dsl_dataset_t *hds;
3510 	struct promotenode *snap;
3511 	dsl_dataset_t *origin_ds;
3512 	dsl_dataset_t *origin_head;
3513 	dsl_dir_t *dd;
3514 	dsl_dir_t *odd = NULL;
3515 	uint64_t oldnext_obj;
3516 	int64_t delta;
3517 
3518 	ASSERT(nvlist_empty(ddpa->err_ds));
3519 
3520 	VERIFY0(promote_hold(ddpa, dp, FTAG));
3521 	hds = ddpa->ddpa_clone;
3522 
3523 	ASSERT0(dsl_dataset_phys(hds)->ds_flags & DS_FLAG_NOPROMOTE);
3524 
3525 	snap = list_head(&ddpa->shared_snaps);
3526 	origin_ds = snap->ds;
3527 	dd = hds->ds_dir;
3528 
3529 	snap = list_head(&ddpa->origin_snaps);
3530 	origin_head = snap->ds;
3531 
3532 	/*
3533 	 * We need to explicitly open odd, since origin_ds's dd will be
3534 	 * changing.
3535 	 */
3536 	VERIFY0(dsl_dir_hold_obj(dp, origin_ds->ds_dir->dd_object,
3537 	    NULL, FTAG, &odd));
3538 
3539 	dsl_dataset_promote_crypt_sync(hds->ds_dir, odd, tx);
3540 
3541 	/* change origin's next snap */
3542 	dmu_buf_will_dirty(origin_ds->ds_dbuf, tx);
3543 	oldnext_obj = dsl_dataset_phys(origin_ds)->ds_next_snap_obj;
3544 	snap = list_tail(&ddpa->clone_snaps);
3545 	ASSERT3U(dsl_dataset_phys(snap->ds)->ds_prev_snap_obj, ==,
3546 	    origin_ds->ds_object);
3547 	dsl_dataset_phys(origin_ds)->ds_next_snap_obj = snap->ds->ds_object;
3548 
3549 	/* change the origin's next clone */
3550 	if (dsl_dataset_phys(origin_ds)->ds_next_clones_obj) {
3551 		dsl_dataset_remove_from_next_clones(origin_ds,
3552 		    snap->ds->ds_object, tx);
3553 		VERIFY0(zap_add_int(dp->dp_meta_objset,
3554 		    dsl_dataset_phys(origin_ds)->ds_next_clones_obj,
3555 		    oldnext_obj, tx));
3556 	}
3557 
3558 	/* change origin */
3559 	dmu_buf_will_dirty(dd->dd_dbuf, tx);
3560 	ASSERT3U(dsl_dir_phys(dd)->dd_origin_obj, ==, origin_ds->ds_object);
3561 	dsl_dir_phys(dd)->dd_origin_obj = dsl_dir_phys(odd)->dd_origin_obj;
3562 	dd->dd_origin_txg = origin_head->ds_dir->dd_origin_txg;
3563 	dmu_buf_will_dirty(odd->dd_dbuf, tx);
3564 	dsl_dir_phys(odd)->dd_origin_obj = origin_ds->ds_object;
3565 	origin_head->ds_dir->dd_origin_txg =
3566 	    dsl_dataset_phys(origin_ds)->ds_creation_txg;
3567 
3568 	/* change dd_clone entries */
3569 	if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
3570 		VERIFY0(zap_remove_int(dp->dp_meta_objset,
3571 		    dsl_dir_phys(odd)->dd_clones, hds->ds_object, tx));
3572 		VERIFY0(zap_add_int(dp->dp_meta_objset,
3573 		    dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
3574 		    hds->ds_object, tx));
3575 
3576 		VERIFY0(zap_remove_int(dp->dp_meta_objset,
3577 		    dsl_dir_phys(ddpa->origin_origin->ds_dir)->dd_clones,
3578 		    origin_head->ds_object, tx));
3579 		if (dsl_dir_phys(dd)->dd_clones == 0) {
3580 			dsl_dir_phys(dd)->dd_clones =
3581 			    zap_create(dp->dp_meta_objset, DMU_OT_DSL_CLONES,
3582 			    DMU_OT_NONE, 0, tx);
3583 		}
3584 		VERIFY0(zap_add_int(dp->dp_meta_objset,
3585 		    dsl_dir_phys(dd)->dd_clones, origin_head->ds_object, tx));
3586 	}
3587 
3588 	/*
3589 	 * Move bookmarks to this dir.
3590 	 */
3591 	dsl_bookmark_node_t *dbn_next;
3592 	for (dsl_bookmark_node_t *dbn = avl_first(&origin_head->ds_bookmarks);
3593 	    dbn != NULL && dbn->dbn_phys.zbm_creation_txg <=
3594 	    dsl_dataset_phys(origin_ds)->ds_creation_txg;
3595 	    dbn = dbn_next) {
3596 		dbn_next = AVL_NEXT(&origin_head->ds_bookmarks, dbn);
3597 
3598 		avl_remove(&origin_head->ds_bookmarks, dbn);
3599 		VERIFY0(zap_remove(dp->dp_meta_objset,
3600 		    origin_head->ds_bookmarks_obj, dbn->dbn_name, tx));
3601 
3602 		dsl_bookmark_node_add(hds, dbn, tx);
3603 	}
3604 
3605 	dsl_bookmark_next_changed(hds, origin_ds, tx);
3606 
3607 	/* move snapshots to this dir */
3608 	for (snap = list_head(&ddpa->shared_snaps); snap;
3609 	    snap = list_next(&ddpa->shared_snaps, snap)) {
3610 		dsl_dataset_t *ds = snap->ds;
3611 
3612 		/*
3613 		 * Property callbacks are registered to a particular
3614 		 * dsl_dir.  Since ours is changing, evict the objset
3615 		 * so that they will be unregistered from the old dsl_dir.
3616 		 */
3617 		if (ds->ds_objset) {
3618 			dmu_objset_evict(ds->ds_objset);
3619 			ds->ds_objset = NULL;
3620 		}
3621 
3622 		/* move snap name entry */
3623 		VERIFY0(dsl_dataset_get_snapname(ds));
3624 		VERIFY0(dsl_dataset_snap_remove(origin_head,
3625 		    ds->ds_snapname, tx, B_TRUE));
3626 		VERIFY0(zap_add(dp->dp_meta_objset,
3627 		    dsl_dataset_phys(hds)->ds_snapnames_zapobj, ds->ds_snapname,
3628 		    8, 1, &ds->ds_object, tx));
3629 		dsl_fs_ss_count_adjust(hds->ds_dir, 1,
3630 		    DD_FIELD_SNAPSHOT_COUNT, tx);
3631 
3632 		/* change containing dsl_dir */
3633 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
3634 		ASSERT3U(dsl_dataset_phys(ds)->ds_dir_obj, ==, odd->dd_object);
3635 		dsl_dataset_phys(ds)->ds_dir_obj = dd->dd_object;
3636 		ASSERT3P(ds->ds_dir, ==, odd);
3637 		dsl_dir_rele(ds->ds_dir, ds);
3638 		VERIFY0(dsl_dir_hold_obj(dp, dd->dd_object,
3639 		    NULL, ds, &ds->ds_dir));
3640 
3641 		/* move any clone references */
3642 		if (dsl_dataset_phys(ds)->ds_next_clones_obj &&
3643 		    spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
3644 			zap_cursor_t zc;
3645 			zap_attribute_t za;
3646 
3647 			for (zap_cursor_init(&zc, dp->dp_meta_objset,
3648 			    dsl_dataset_phys(ds)->ds_next_clones_obj);
3649 			    zap_cursor_retrieve(&zc, &za) == 0;
3650 			    zap_cursor_advance(&zc)) {
3651 				dsl_dataset_t *cnds;
3652 				uint64_t o;
3653 
3654 				if (za.za_first_integer == oldnext_obj) {
3655 					/*
3656 					 * We've already moved the
3657 					 * origin's reference.
3658 					 */
3659 					continue;
3660 				}
3661 
3662 				VERIFY0(dsl_dataset_hold_obj(dp,
3663 				    za.za_first_integer, FTAG, &cnds));
3664 				o = dsl_dir_phys(cnds->ds_dir)->
3665 				    dd_head_dataset_obj;
3666 
3667 				VERIFY0(zap_remove_int(dp->dp_meta_objset,
3668 				    dsl_dir_phys(odd)->dd_clones, o, tx));
3669 				VERIFY0(zap_add_int(dp->dp_meta_objset,
3670 				    dsl_dir_phys(dd)->dd_clones, o, tx));
3671 				dsl_dataset_rele(cnds, FTAG);
3672 			}
3673 			zap_cursor_fini(&zc);
3674 		}
3675 
3676 		ASSERT(!dsl_prop_hascb(ds));
3677 	}
3678 
3679 	/*
3680 	 * Change space accounting.
3681 	 * Note, pa->*usedsnap and dd_used_breakdown[SNAP] will either
3682 	 * both be valid, or both be 0 (resulting in delta == 0).  This
3683 	 * is true for each of {clone,origin} independently.
3684 	 */
3685 
3686 	delta = ddpa->cloneusedsnap -
3687 	    dsl_dir_phys(dd)->dd_used_breakdown[DD_USED_SNAP];
3688 	ASSERT3S(delta, >=, 0);
3689 	ASSERT3U(ddpa->used, >=, delta);
3690 	dsl_dir_diduse_space(dd, DD_USED_SNAP, delta, 0, 0, tx);
3691 	dsl_dir_diduse_space(dd, DD_USED_HEAD,
3692 	    ddpa->used - delta, ddpa->comp, ddpa->uncomp, tx);
3693 
3694 	delta = ddpa->originusedsnap -
3695 	    dsl_dir_phys(odd)->dd_used_breakdown[DD_USED_SNAP];
3696 	ASSERT3S(delta, <=, 0);
3697 	ASSERT3U(ddpa->used, >=, -delta);
3698 	dsl_dir_diduse_space(odd, DD_USED_SNAP, delta, 0, 0, tx);
3699 	dsl_dir_diduse_space(odd, DD_USED_HEAD,
3700 	    -ddpa->used - delta, -ddpa->comp, -ddpa->uncomp, tx);
3701 
3702 	dsl_dataset_phys(origin_ds)->ds_unique_bytes = ddpa->unique;
3703 
3704 	/*
3705 	 * Since livelists are specific to a clone's origin txg, they
3706 	 * are no longer accurate. Destroy the livelist from the clone being
3707 	 * promoted. If the origin dataset is a clone, destroy its livelist
3708 	 * as well.
3709 	 */
3710 	dsl_dir_remove_livelist(dd, tx, B_TRUE);
3711 	dsl_dir_remove_livelist(odd, tx, B_TRUE);
3712 
3713 	/* log history record */
3714 	spa_history_log_internal_ds(hds, "promote", tx, " ");
3715 
3716 	dsl_dir_rele(odd, FTAG);
3717 	promote_rele(ddpa, FTAG);
3718 
3719 	/*
3720 	 * Transfer common error blocks from old head to new head.
3721 	 */
3722 	if (spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_HEAD_ERRLOG)) {
3723 		uint64_t old_head = origin_head->ds_object;
3724 		uint64_t new_head = hds->ds_object;
3725 		spa_swap_errlog(dp->dp_spa, new_head, old_head, tx);
3726 	}
3727 }
3728 
3729 /*
3730  * Make a list of dsl_dataset_t's for the snapshots between first_obj
3731  * (exclusive) and last_obj (inclusive).  The list will be in reverse
3732  * order (last_obj will be the list_head()).  If first_obj == 0, do all
3733  * snapshots back to this dataset's origin.
3734  */
3735 static int
3736 snaplist_make(dsl_pool_t *dp,
3737     uint64_t first_obj, uint64_t last_obj, list_t *l, const void *tag)
3738 {
3739 	uint64_t obj = last_obj;
3740 
3741 	list_create(l, sizeof (struct promotenode),
3742 	    offsetof(struct promotenode, link));
3743 
3744 	while (obj != first_obj) {
3745 		dsl_dataset_t *ds;
3746 		struct promotenode *snap;
3747 		int err;
3748 
3749 		err = dsl_dataset_hold_obj(dp, obj, tag, &ds);
3750 		ASSERT(err != ENOENT);
3751 		if (err != 0)
3752 			return (err);
3753 
3754 		if (first_obj == 0)
3755 			first_obj = dsl_dir_phys(ds->ds_dir)->dd_origin_obj;
3756 
3757 		snap = kmem_alloc(sizeof (*snap), KM_SLEEP);
3758 		snap->ds = ds;
3759 		list_insert_tail(l, snap);
3760 		obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
3761 	}
3762 
3763 	return (0);
3764 }
3765 
3766 static int
3767 snaplist_space(list_t *l, uint64_t mintxg, uint64_t *spacep)
3768 {
3769 	struct promotenode *snap;
3770 
3771 	*spacep = 0;
3772 	for (snap = list_head(l); snap; snap = list_next(l, snap)) {
3773 		uint64_t used, comp, uncomp;
3774 		dsl_deadlist_space_range(&snap->ds->ds_deadlist,
3775 		    mintxg, UINT64_MAX, &used, &comp, &uncomp);
3776 		*spacep += used;
3777 	}
3778 	return (0);
3779 }
3780 
3781 static void
3782 snaplist_destroy(list_t *l, const void *tag)
3783 {
3784 	struct promotenode *snap;
3785 
3786 	if (l == NULL || !list_link_active(&l->list_head))
3787 		return;
3788 
3789 	while ((snap = list_tail(l)) != NULL) {
3790 		list_remove(l, snap);
3791 		dsl_dataset_rele(snap->ds, tag);
3792 		kmem_free(snap, sizeof (*snap));
3793 	}
3794 	list_destroy(l);
3795 }
3796 
3797 static int
3798 promote_hold(dsl_dataset_promote_arg_t *ddpa, dsl_pool_t *dp, const void *tag)
3799 {
3800 	int error;
3801 	dsl_dir_t *dd;
3802 	struct promotenode *snap;
3803 
3804 	error = dsl_dataset_hold(dp, ddpa->ddpa_clonename, tag,
3805 	    &ddpa->ddpa_clone);
3806 	if (error != 0)
3807 		return (error);
3808 	dd = ddpa->ddpa_clone->ds_dir;
3809 
3810 	if (ddpa->ddpa_clone->ds_is_snapshot ||
3811 	    !dsl_dir_is_clone(dd)) {
3812 		dsl_dataset_rele(ddpa->ddpa_clone, tag);
3813 		return (SET_ERROR(EINVAL));
3814 	}
3815 
3816 	error = snaplist_make(dp, 0, dsl_dir_phys(dd)->dd_origin_obj,
3817 	    &ddpa->shared_snaps, tag);
3818 	if (error != 0)
3819 		goto out;
3820 
3821 	error = snaplist_make(dp, 0, ddpa->ddpa_clone->ds_object,
3822 	    &ddpa->clone_snaps, tag);
3823 	if (error != 0)
3824 		goto out;
3825 
3826 	snap = list_head(&ddpa->shared_snaps);
3827 	ASSERT3U(snap->ds->ds_object, ==, dsl_dir_phys(dd)->dd_origin_obj);
3828 	error = snaplist_make(dp, dsl_dir_phys(dd)->dd_origin_obj,
3829 	    dsl_dir_phys(snap->ds->ds_dir)->dd_head_dataset_obj,
3830 	    &ddpa->origin_snaps, tag);
3831 	if (error != 0)
3832 		goto out;
3833 
3834 	if (dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj != 0) {
3835 		error = dsl_dataset_hold_obj(dp,
3836 		    dsl_dir_phys(snap->ds->ds_dir)->dd_origin_obj,
3837 		    tag, &ddpa->origin_origin);
3838 		if (error != 0)
3839 			goto out;
3840 	}
3841 out:
3842 	if (error != 0)
3843 		promote_rele(ddpa, tag);
3844 	return (error);
3845 }
3846 
3847 static void
3848 promote_rele(dsl_dataset_promote_arg_t *ddpa, const void *tag)
3849 {
3850 	snaplist_destroy(&ddpa->shared_snaps, tag);
3851 	snaplist_destroy(&ddpa->clone_snaps, tag);
3852 	snaplist_destroy(&ddpa->origin_snaps, tag);
3853 	if (ddpa->origin_origin != NULL)
3854 		dsl_dataset_rele(ddpa->origin_origin, tag);
3855 	dsl_dataset_rele(ddpa->ddpa_clone, tag);
3856 }
3857 
3858 /*
3859  * Promote a clone.
3860  *
3861  * If it fails due to a conflicting snapshot name, "conflsnap" will be filled
3862  * in with the name.  (It must be at least ZFS_MAX_DATASET_NAME_LEN bytes long.)
3863  */
3864 int
3865 dsl_dataset_promote(const char *name, char *conflsnap)
3866 {
3867 	dsl_dataset_promote_arg_t ddpa = { 0 };
3868 	uint64_t numsnaps;
3869 	int error;
3870 	nvpair_t *snap_pair;
3871 	objset_t *os;
3872 
3873 	/*
3874 	 * We will modify space proportional to the number of
3875 	 * snapshots.  Compute numsnaps.
3876 	 */
3877 	error = dmu_objset_hold(name, FTAG, &os);
3878 	if (error != 0)
3879 		return (error);
3880 	error = zap_count(dmu_objset_pool(os)->dp_meta_objset,
3881 	    dsl_dataset_phys(dmu_objset_ds(os))->ds_snapnames_zapobj,
3882 	    &numsnaps);
3883 	dmu_objset_rele(os, FTAG);
3884 	if (error != 0)
3885 		return (error);
3886 
3887 	ddpa.ddpa_clonename = name;
3888 	ddpa.err_ds = fnvlist_alloc();
3889 	ddpa.cr = CRED();
3890 	ddpa.proc = curproc;
3891 
3892 	error = dsl_sync_task(name, dsl_dataset_promote_check,
3893 	    dsl_dataset_promote_sync, &ddpa,
3894 	    2 + numsnaps, ZFS_SPACE_CHECK_RESERVED);
3895 
3896 	/*
3897 	 * Return the first conflicting snapshot found.
3898 	 */
3899 	snap_pair = nvlist_next_nvpair(ddpa.err_ds, NULL);
3900 	if (snap_pair != NULL && conflsnap != NULL)
3901 		(void) strlcpy(conflsnap, nvpair_name(snap_pair),
3902 		    ZFS_MAX_DATASET_NAME_LEN);
3903 
3904 	fnvlist_free(ddpa.err_ds);
3905 	return (error);
3906 }
3907 
3908 int
3909 dsl_dataset_clone_swap_check_impl(dsl_dataset_t *clone,
3910     dsl_dataset_t *origin_head, boolean_t force, void *owner, dmu_tx_t *tx)
3911 {
3912 	/*
3913 	 * "slack" factor for received datasets with refquota set on them.
3914 	 * See the bottom of this function for details on its use.
3915 	 */
3916 	uint64_t refquota_slack = (uint64_t)DMU_MAX_ACCESS *
3917 	    spa_asize_inflation;
3918 	int64_t unused_refres_delta;
3919 
3920 	/* they should both be heads */
3921 	if (clone->ds_is_snapshot ||
3922 	    origin_head->ds_is_snapshot)
3923 		return (SET_ERROR(EINVAL));
3924 
3925 	/* if we are not forcing, the branch point should be just before them */
3926 	if (!force && clone->ds_prev != origin_head->ds_prev)
3927 		return (SET_ERROR(EINVAL));
3928 
3929 	/* clone should be the clone (unless they are unrelated) */
3930 	if (clone->ds_prev != NULL &&
3931 	    clone->ds_prev != clone->ds_dir->dd_pool->dp_origin_snap &&
3932 	    origin_head->ds_dir != clone->ds_prev->ds_dir)
3933 		return (SET_ERROR(EINVAL));
3934 
3935 	/* the clone should be a child of the origin */
3936 	if (clone->ds_dir->dd_parent != origin_head->ds_dir)
3937 		return (SET_ERROR(EINVAL));
3938 
3939 	/* origin_head shouldn't be modified unless 'force' */
3940 	if (!force &&
3941 	    dsl_dataset_modified_since_snap(origin_head, origin_head->ds_prev))
3942 		return (SET_ERROR(ETXTBSY));
3943 
3944 	/* origin_head should have no long holds (e.g. is not mounted) */
3945 	if (dsl_dataset_handoff_check(origin_head, owner, tx))
3946 		return (SET_ERROR(EBUSY));
3947 
3948 	/* check amount of any unconsumed refreservation */
3949 	unused_refres_delta =
3950 	    (int64_t)MIN(origin_head->ds_reserved,
3951 	    dsl_dataset_phys(origin_head)->ds_unique_bytes) -
3952 	    (int64_t)MIN(origin_head->ds_reserved,
3953 	    dsl_dataset_phys(clone)->ds_unique_bytes);
3954 
3955 	if (unused_refres_delta > 0 &&
3956 	    unused_refres_delta >
3957 	    dsl_dir_space_available(origin_head->ds_dir, NULL, 0, TRUE))
3958 		return (SET_ERROR(ENOSPC));
3959 
3960 	/*
3961 	 * The clone can't be too much over the head's refquota.
3962 	 *
3963 	 * To ensure that the entire refquota can be used, we allow one
3964 	 * transaction to exceed the refquota.  Therefore, this check
3965 	 * needs to also allow for the space referenced to be more than the
3966 	 * refquota.  The maximum amount of space that one transaction can use
3967 	 * on disk is DMU_MAX_ACCESS * spa_asize_inflation.  Allowing this
3968 	 * overage ensures that we are able to receive a filesystem that
3969 	 * exceeds the refquota on the source system.
3970 	 *
3971 	 * So that overage is the refquota_slack we use below.
3972 	 */
3973 	if (origin_head->ds_quota != 0 &&
3974 	    dsl_dataset_phys(clone)->ds_referenced_bytes >
3975 	    origin_head->ds_quota + refquota_slack)
3976 		return (SET_ERROR(EDQUOT));
3977 
3978 	return (0);
3979 }
3980 
3981 static void
3982 dsl_dataset_swap_remap_deadlists(dsl_dataset_t *clone,
3983     dsl_dataset_t *origin, dmu_tx_t *tx)
3984 {
3985 	uint64_t clone_remap_dl_obj, origin_remap_dl_obj;
3986 	dsl_pool_t *dp = dmu_tx_pool(tx);
3987 
3988 	ASSERT(dsl_pool_sync_context(dp));
3989 
3990 	clone_remap_dl_obj = dsl_dataset_get_remap_deadlist_object(clone);
3991 	origin_remap_dl_obj = dsl_dataset_get_remap_deadlist_object(origin);
3992 
3993 	if (clone_remap_dl_obj != 0) {
3994 		dsl_deadlist_close(&clone->ds_remap_deadlist);
3995 		dsl_dataset_unset_remap_deadlist_object(clone, tx);
3996 	}
3997 	if (origin_remap_dl_obj != 0) {
3998 		dsl_deadlist_close(&origin->ds_remap_deadlist);
3999 		dsl_dataset_unset_remap_deadlist_object(origin, tx);
4000 	}
4001 
4002 	if (clone_remap_dl_obj != 0) {
4003 		dsl_dataset_set_remap_deadlist_object(origin,
4004 		    clone_remap_dl_obj, tx);
4005 		dsl_deadlist_open(&origin->ds_remap_deadlist,
4006 		    dp->dp_meta_objset, clone_remap_dl_obj);
4007 	}
4008 	if (origin_remap_dl_obj != 0) {
4009 		dsl_dataset_set_remap_deadlist_object(clone,
4010 		    origin_remap_dl_obj, tx);
4011 		dsl_deadlist_open(&clone->ds_remap_deadlist,
4012 		    dp->dp_meta_objset, origin_remap_dl_obj);
4013 	}
4014 }
4015 
4016 void
4017 dsl_dataset_clone_swap_sync_impl(dsl_dataset_t *clone,
4018     dsl_dataset_t *origin_head, dmu_tx_t *tx)
4019 {
4020 	dsl_pool_t *dp = dmu_tx_pool(tx);
4021 	int64_t unused_refres_delta;
4022 
4023 	ASSERT(clone->ds_reserved == 0);
4024 	/*
4025 	 * NOTE: On DEBUG kernels there could be a race between this and
4026 	 * the check function if spa_asize_inflation is adjusted...
4027 	 */
4028 	ASSERT(origin_head->ds_quota == 0 ||
4029 	    dsl_dataset_phys(clone)->ds_unique_bytes <= origin_head->ds_quota +
4030 	    DMU_MAX_ACCESS * spa_asize_inflation);
4031 	ASSERT3P(clone->ds_prev, ==, origin_head->ds_prev);
4032 
4033 	dsl_dir_cancel_waiters(origin_head->ds_dir);
4034 
4035 	/*
4036 	 * Swap per-dataset feature flags.
4037 	 */
4038 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
4039 		if (!(spa_feature_table[f].fi_flags &
4040 		    ZFEATURE_FLAG_PER_DATASET)) {
4041 			ASSERT(!dsl_dataset_feature_is_active(clone, f));
4042 			ASSERT(!dsl_dataset_feature_is_active(origin_head, f));
4043 			continue;
4044 		}
4045 
4046 		boolean_t clone_inuse = dsl_dataset_feature_is_active(clone, f);
4047 		void *clone_feature = clone->ds_feature[f];
4048 		boolean_t origin_head_inuse =
4049 		    dsl_dataset_feature_is_active(origin_head, f);
4050 		void *origin_head_feature = origin_head->ds_feature[f];
4051 
4052 		if (clone_inuse)
4053 			dsl_dataset_deactivate_feature_impl(clone, f, tx);
4054 		if (origin_head_inuse)
4055 			dsl_dataset_deactivate_feature_impl(origin_head, f, tx);
4056 
4057 		if (clone_inuse) {
4058 			dsl_dataset_activate_feature(origin_head->ds_object, f,
4059 			    clone_feature, tx);
4060 			origin_head->ds_feature[f] = clone_feature;
4061 		}
4062 		if (origin_head_inuse) {
4063 			dsl_dataset_activate_feature(clone->ds_object, f,
4064 			    origin_head_feature, tx);
4065 			clone->ds_feature[f] = origin_head_feature;
4066 		}
4067 	}
4068 
4069 	dmu_buf_will_dirty(clone->ds_dbuf, tx);
4070 	dmu_buf_will_dirty(origin_head->ds_dbuf, tx);
4071 
4072 	if (clone->ds_objset != NULL) {
4073 		dmu_objset_evict(clone->ds_objset);
4074 		clone->ds_objset = NULL;
4075 	}
4076 
4077 	if (origin_head->ds_objset != NULL) {
4078 		dmu_objset_evict(origin_head->ds_objset);
4079 		origin_head->ds_objset = NULL;
4080 	}
4081 
4082 	unused_refres_delta =
4083 	    (int64_t)MIN(origin_head->ds_reserved,
4084 	    dsl_dataset_phys(origin_head)->ds_unique_bytes) -
4085 	    (int64_t)MIN(origin_head->ds_reserved,
4086 	    dsl_dataset_phys(clone)->ds_unique_bytes);
4087 
4088 	/*
4089 	 * Reset origin's unique bytes.
4090 	 */
4091 	{
4092 		dsl_dataset_t *origin = clone->ds_prev;
4093 		uint64_t comp, uncomp;
4094 
4095 		dmu_buf_will_dirty(origin->ds_dbuf, tx);
4096 		dsl_deadlist_space_range(&clone->ds_deadlist,
4097 		    dsl_dataset_phys(origin)->ds_prev_snap_txg, UINT64_MAX,
4098 		    &dsl_dataset_phys(origin)->ds_unique_bytes, &comp, &uncomp);
4099 	}
4100 
4101 	/* swap blkptrs */
4102 	{
4103 		rrw_enter(&clone->ds_bp_rwlock, RW_WRITER, FTAG);
4104 		rrw_enter(&origin_head->ds_bp_rwlock, RW_WRITER, FTAG);
4105 		blkptr_t tmp;
4106 		tmp = dsl_dataset_phys(origin_head)->ds_bp;
4107 		dsl_dataset_phys(origin_head)->ds_bp =
4108 		    dsl_dataset_phys(clone)->ds_bp;
4109 		dsl_dataset_phys(clone)->ds_bp = tmp;
4110 		rrw_exit(&origin_head->ds_bp_rwlock, FTAG);
4111 		rrw_exit(&clone->ds_bp_rwlock, FTAG);
4112 	}
4113 
4114 	/* set dd_*_bytes */
4115 	{
4116 		int64_t dused, dcomp, duncomp;
4117 		uint64_t cdl_used, cdl_comp, cdl_uncomp;
4118 		uint64_t odl_used, odl_comp, odl_uncomp;
4119 
4120 		ASSERT3U(dsl_dir_phys(clone->ds_dir)->
4121 		    dd_used_breakdown[DD_USED_SNAP], ==, 0);
4122 
4123 		dsl_deadlist_space(&clone->ds_deadlist,
4124 		    &cdl_used, &cdl_comp, &cdl_uncomp);
4125 		dsl_deadlist_space(&origin_head->ds_deadlist,
4126 		    &odl_used, &odl_comp, &odl_uncomp);
4127 
4128 		dused = dsl_dataset_phys(clone)->ds_referenced_bytes +
4129 		    cdl_used -
4130 		    (dsl_dataset_phys(origin_head)->ds_referenced_bytes +
4131 		    odl_used);
4132 		dcomp = dsl_dataset_phys(clone)->ds_compressed_bytes +
4133 		    cdl_comp -
4134 		    (dsl_dataset_phys(origin_head)->ds_compressed_bytes +
4135 		    odl_comp);
4136 		duncomp = dsl_dataset_phys(clone)->ds_uncompressed_bytes +
4137 		    cdl_uncomp -
4138 		    (dsl_dataset_phys(origin_head)->ds_uncompressed_bytes +
4139 		    odl_uncomp);
4140 
4141 		dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_HEAD,
4142 		    dused, dcomp, duncomp, tx);
4143 		dsl_dir_diduse_space(clone->ds_dir, DD_USED_HEAD,
4144 		    -dused, -dcomp, -duncomp, tx);
4145 
4146 		/*
4147 		 * The difference in the space used by snapshots is the
4148 		 * difference in snapshot space due to the head's
4149 		 * deadlist (since that's the only thing that's
4150 		 * changing that affects the snapused).
4151 		 */
4152 		dsl_deadlist_space_range(&clone->ds_deadlist,
4153 		    origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
4154 		    &cdl_used, &cdl_comp, &cdl_uncomp);
4155 		dsl_deadlist_space_range(&origin_head->ds_deadlist,
4156 		    origin_head->ds_dir->dd_origin_txg, UINT64_MAX,
4157 		    &odl_used, &odl_comp, &odl_uncomp);
4158 		dsl_dir_transfer_space(origin_head->ds_dir, cdl_used - odl_used,
4159 		    DD_USED_HEAD, DD_USED_SNAP, tx);
4160 	}
4161 
4162 	/* swap ds_*_bytes */
4163 	SWITCH64(dsl_dataset_phys(origin_head)->ds_referenced_bytes,
4164 	    dsl_dataset_phys(clone)->ds_referenced_bytes);
4165 	SWITCH64(dsl_dataset_phys(origin_head)->ds_compressed_bytes,
4166 	    dsl_dataset_phys(clone)->ds_compressed_bytes);
4167 	SWITCH64(dsl_dataset_phys(origin_head)->ds_uncompressed_bytes,
4168 	    dsl_dataset_phys(clone)->ds_uncompressed_bytes);
4169 	SWITCH64(dsl_dataset_phys(origin_head)->ds_unique_bytes,
4170 	    dsl_dataset_phys(clone)->ds_unique_bytes);
4171 
4172 	/* apply any parent delta for change in unconsumed refreservation */
4173 	dsl_dir_diduse_space(origin_head->ds_dir, DD_USED_REFRSRV,
4174 	    unused_refres_delta, 0, 0, tx);
4175 
4176 	/*
4177 	 * Swap deadlists.
4178 	 */
4179 	dsl_deadlist_close(&clone->ds_deadlist);
4180 	dsl_deadlist_close(&origin_head->ds_deadlist);
4181 	SWITCH64(dsl_dataset_phys(origin_head)->ds_deadlist_obj,
4182 	    dsl_dataset_phys(clone)->ds_deadlist_obj);
4183 	dsl_deadlist_open(&clone->ds_deadlist, dp->dp_meta_objset,
4184 	    dsl_dataset_phys(clone)->ds_deadlist_obj);
4185 	dsl_deadlist_open(&origin_head->ds_deadlist, dp->dp_meta_objset,
4186 	    dsl_dataset_phys(origin_head)->ds_deadlist_obj);
4187 	dsl_dataset_swap_remap_deadlists(clone, origin_head, tx);
4188 
4189 	/*
4190 	 * If there is a bookmark at the origin, its "next dataset" is
4191 	 * changing, so we need to reset its FBN.
4192 	 */
4193 	dsl_bookmark_next_changed(origin_head, origin_head->ds_prev, tx);
4194 
4195 	dsl_scan_ds_clone_swapped(origin_head, clone, tx);
4196 
4197 	/*
4198 	 * Destroy any livelists associated with the clone or the origin,
4199 	 * since after the swap the corresponding livelists are no longer
4200 	 * valid.
4201 	 */
4202 	dsl_dir_remove_livelist(clone->ds_dir, tx, B_TRUE);
4203 	dsl_dir_remove_livelist(origin_head->ds_dir, tx, B_TRUE);
4204 
4205 	spa_history_log_internal_ds(clone, "clone swap", tx,
4206 	    "parent=%s", origin_head->ds_dir->dd_myname);
4207 }
4208 
4209 /*
4210  * Given a pool name and a dataset object number in that pool,
4211  * return the name of that dataset.
4212  */
4213 int
4214 dsl_dsobj_to_dsname(char *pname, uint64_t obj, char *buf)
4215 {
4216 	dsl_pool_t *dp;
4217 	dsl_dataset_t *ds;
4218 	int error;
4219 
4220 	error = dsl_pool_hold(pname, FTAG, &dp);
4221 	if (error != 0)
4222 		return (error);
4223 
4224 	error = dsl_dataset_hold_obj(dp, obj, FTAG, &ds);
4225 	if (error == 0) {
4226 		dsl_dataset_name(ds, buf);
4227 		dsl_dataset_rele(ds, FTAG);
4228 	}
4229 	dsl_pool_rele(dp, FTAG);
4230 
4231 	return (error);
4232 }
4233 
4234 int
4235 dsl_dataset_check_quota(dsl_dataset_t *ds, boolean_t check_quota,
4236     uint64_t asize, uint64_t inflight, uint64_t *used, uint64_t *ref_rsrv)
4237 {
4238 	int error = 0;
4239 
4240 	ASSERT3S(asize, >, 0);
4241 
4242 	/*
4243 	 * *ref_rsrv is the portion of asize that will come from any
4244 	 * unconsumed refreservation space.
4245 	 */
4246 	*ref_rsrv = 0;
4247 
4248 	mutex_enter(&ds->ds_lock);
4249 	/*
4250 	 * Make a space adjustment for reserved bytes.
4251 	 */
4252 	if (ds->ds_reserved > dsl_dataset_phys(ds)->ds_unique_bytes) {
4253 		ASSERT3U(*used, >=,
4254 		    ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
4255 		*used -=
4256 		    (ds->ds_reserved - dsl_dataset_phys(ds)->ds_unique_bytes);
4257 		*ref_rsrv =
4258 		    asize - MIN(asize, parent_delta(ds, asize + inflight));
4259 	}
4260 
4261 	if (!check_quota || ds->ds_quota == 0) {
4262 		mutex_exit(&ds->ds_lock);
4263 		return (0);
4264 	}
4265 	/*
4266 	 * If they are requesting more space, and our current estimate
4267 	 * is over quota, they get to try again unless the actual
4268 	 * on-disk is over quota and there are no pending changes (which
4269 	 * may free up space for us).
4270 	 */
4271 	if (dsl_dataset_phys(ds)->ds_referenced_bytes + inflight >=
4272 	    ds->ds_quota) {
4273 		if (inflight > 0 ||
4274 		    dsl_dataset_phys(ds)->ds_referenced_bytes < ds->ds_quota)
4275 			error = SET_ERROR(ERESTART);
4276 		else
4277 			error = SET_ERROR(EDQUOT);
4278 	}
4279 	mutex_exit(&ds->ds_lock);
4280 
4281 	return (error);
4282 }
4283 
4284 typedef struct dsl_dataset_set_qr_arg {
4285 	const char *ddsqra_name;
4286 	zprop_source_t ddsqra_source;
4287 	uint64_t ddsqra_value;
4288 } dsl_dataset_set_qr_arg_t;
4289 
4290 
4291 static int
4292 dsl_dataset_set_refquota_check(void *arg, dmu_tx_t *tx)
4293 {
4294 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
4295 	dsl_pool_t *dp = dmu_tx_pool(tx);
4296 	dsl_dataset_t *ds;
4297 	int error;
4298 	uint64_t newval;
4299 
4300 	if (spa_version(dp->dp_spa) < SPA_VERSION_REFQUOTA)
4301 		return (SET_ERROR(ENOTSUP));
4302 
4303 	error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
4304 	if (error != 0)
4305 		return (error);
4306 
4307 	if (ds->ds_is_snapshot) {
4308 		dsl_dataset_rele(ds, FTAG);
4309 		return (SET_ERROR(EINVAL));
4310 	}
4311 
4312 	error = dsl_prop_predict(ds->ds_dir,
4313 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
4314 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
4315 	if (error != 0) {
4316 		dsl_dataset_rele(ds, FTAG);
4317 		return (error);
4318 	}
4319 
4320 	if (newval == 0) {
4321 		dsl_dataset_rele(ds, FTAG);
4322 		return (0);
4323 	}
4324 
4325 	if (newval < dsl_dataset_phys(ds)->ds_referenced_bytes ||
4326 	    newval < ds->ds_reserved) {
4327 		dsl_dataset_rele(ds, FTAG);
4328 		return (SET_ERROR(ENOSPC));
4329 	}
4330 
4331 	dsl_dataset_rele(ds, FTAG);
4332 	return (0);
4333 }
4334 
4335 static void
4336 dsl_dataset_set_refquota_sync(void *arg, dmu_tx_t *tx)
4337 {
4338 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
4339 	dsl_pool_t *dp = dmu_tx_pool(tx);
4340 	dsl_dataset_t *ds = NULL;
4341 	uint64_t newval;
4342 
4343 	VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
4344 
4345 	dsl_prop_set_sync_impl(ds,
4346 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA),
4347 	    ddsqra->ddsqra_source, sizeof (ddsqra->ddsqra_value), 1,
4348 	    &ddsqra->ddsqra_value, tx);
4349 
4350 	VERIFY0(dsl_prop_get_int_ds(ds,
4351 	    zfs_prop_to_name(ZFS_PROP_REFQUOTA), &newval));
4352 
4353 	if (ds->ds_quota != newval) {
4354 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
4355 		ds->ds_quota = newval;
4356 	}
4357 	dsl_dataset_rele(ds, FTAG);
4358 }
4359 
4360 int
4361 dsl_dataset_set_refquota(const char *dsname, zprop_source_t source,
4362     uint64_t refquota)
4363 {
4364 	dsl_dataset_set_qr_arg_t ddsqra;
4365 
4366 	ddsqra.ddsqra_name = dsname;
4367 	ddsqra.ddsqra_source = source;
4368 	ddsqra.ddsqra_value = refquota;
4369 
4370 	return (dsl_sync_task(dsname, dsl_dataset_set_refquota_check,
4371 	    dsl_dataset_set_refquota_sync, &ddsqra, 0,
4372 	    ZFS_SPACE_CHECK_EXTRA_RESERVED));
4373 }
4374 
4375 static int
4376 dsl_dataset_set_refreservation_check(void *arg, dmu_tx_t *tx)
4377 {
4378 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
4379 	dsl_pool_t *dp = dmu_tx_pool(tx);
4380 	dsl_dataset_t *ds;
4381 	int error;
4382 	uint64_t newval, unique;
4383 
4384 	if (spa_version(dp->dp_spa) < SPA_VERSION_REFRESERVATION)
4385 		return (SET_ERROR(ENOTSUP));
4386 
4387 	error = dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds);
4388 	if (error != 0)
4389 		return (error);
4390 
4391 	if (ds->ds_is_snapshot) {
4392 		dsl_dataset_rele(ds, FTAG);
4393 		return (SET_ERROR(EINVAL));
4394 	}
4395 
4396 	error = dsl_prop_predict(ds->ds_dir,
4397 	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
4398 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, &newval);
4399 	if (error != 0) {
4400 		dsl_dataset_rele(ds, FTAG);
4401 		return (error);
4402 	}
4403 
4404 	/*
4405 	 * If we are doing the preliminary check in open context, the
4406 	 * space estimates may be inaccurate.
4407 	 */
4408 	if (!dmu_tx_is_syncing(tx)) {
4409 		dsl_dataset_rele(ds, FTAG);
4410 		return (0);
4411 	}
4412 
4413 	mutex_enter(&ds->ds_lock);
4414 	if (!DS_UNIQUE_IS_ACCURATE(ds))
4415 		dsl_dataset_recalc_head_uniq(ds);
4416 	unique = dsl_dataset_phys(ds)->ds_unique_bytes;
4417 	mutex_exit(&ds->ds_lock);
4418 
4419 	if (MAX(unique, newval) > MAX(unique, ds->ds_reserved)) {
4420 		uint64_t delta = MAX(unique, newval) -
4421 		    MAX(unique, ds->ds_reserved);
4422 
4423 		if (delta >
4424 		    dsl_dir_space_available(ds->ds_dir, NULL, 0, B_TRUE) ||
4425 		    (ds->ds_quota > 0 && newval > ds->ds_quota)) {
4426 			dsl_dataset_rele(ds, FTAG);
4427 			return (SET_ERROR(ENOSPC));
4428 		}
4429 	}
4430 
4431 	dsl_dataset_rele(ds, FTAG);
4432 	return (0);
4433 }
4434 
4435 void
4436 dsl_dataset_set_refreservation_sync_impl(dsl_dataset_t *ds,
4437     zprop_source_t source, uint64_t value, dmu_tx_t *tx)
4438 {
4439 	uint64_t newval;
4440 	uint64_t unique;
4441 	int64_t delta;
4442 
4443 	dsl_prop_set_sync_impl(ds, zfs_prop_to_name(ZFS_PROP_REFRESERVATION),
4444 	    source, sizeof (value), 1, &value, tx);
4445 
4446 	VERIFY0(dsl_prop_get_int_ds(ds,
4447 	    zfs_prop_to_name(ZFS_PROP_REFRESERVATION), &newval));
4448 
4449 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
4450 	mutex_enter(&ds->ds_dir->dd_lock);
4451 	mutex_enter(&ds->ds_lock);
4452 	ASSERT(DS_UNIQUE_IS_ACCURATE(ds));
4453 	unique = dsl_dataset_phys(ds)->ds_unique_bytes;
4454 	delta = MAX(0, (int64_t)(newval - unique)) -
4455 	    MAX(0, (int64_t)(ds->ds_reserved - unique));
4456 	ds->ds_reserved = newval;
4457 	mutex_exit(&ds->ds_lock);
4458 
4459 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_REFRSRV, delta, 0, 0, tx);
4460 	mutex_exit(&ds->ds_dir->dd_lock);
4461 }
4462 
4463 static void
4464 dsl_dataset_set_refreservation_sync(void *arg, dmu_tx_t *tx)
4465 {
4466 	dsl_dataset_set_qr_arg_t *ddsqra = arg;
4467 	dsl_pool_t *dp = dmu_tx_pool(tx);
4468 	dsl_dataset_t *ds = NULL;
4469 
4470 	VERIFY0(dsl_dataset_hold(dp, ddsqra->ddsqra_name, FTAG, &ds));
4471 	dsl_dataset_set_refreservation_sync_impl(ds,
4472 	    ddsqra->ddsqra_source, ddsqra->ddsqra_value, tx);
4473 	dsl_dataset_rele(ds, FTAG);
4474 }
4475 
4476 int
4477 dsl_dataset_set_refreservation(const char *dsname, zprop_source_t source,
4478     uint64_t refreservation)
4479 {
4480 	dsl_dataset_set_qr_arg_t ddsqra;
4481 
4482 	ddsqra.ddsqra_name = dsname;
4483 	ddsqra.ddsqra_source = source;
4484 	ddsqra.ddsqra_value = refreservation;
4485 
4486 	return (dsl_sync_task(dsname, dsl_dataset_set_refreservation_check,
4487 	    dsl_dataset_set_refreservation_sync, &ddsqra, 0,
4488 	    ZFS_SPACE_CHECK_EXTRA_RESERVED));
4489 }
4490 
4491 typedef struct dsl_dataset_set_compression_arg {
4492 	const char *ddsca_name;
4493 	zprop_source_t ddsca_source;
4494 	uint64_t ddsca_value;
4495 } dsl_dataset_set_compression_arg_t;
4496 
4497 static int
4498 dsl_dataset_set_compression_check(void *arg, dmu_tx_t *tx)
4499 {
4500 	dsl_dataset_set_compression_arg_t *ddsca = arg;
4501 	dsl_pool_t *dp = dmu_tx_pool(tx);
4502 
4503 	uint64_t compval = ZIO_COMPRESS_ALGO(ddsca->ddsca_value);
4504 	spa_feature_t f = zio_compress_to_feature(compval);
4505 
4506 	if (f == SPA_FEATURE_NONE)
4507 		return (SET_ERROR(EINVAL));
4508 
4509 	if (!spa_feature_is_enabled(dp->dp_spa, f))
4510 		return (SET_ERROR(ENOTSUP));
4511 
4512 	return (0);
4513 }
4514 
4515 static void
4516 dsl_dataset_set_compression_sync(void *arg, dmu_tx_t *tx)
4517 {
4518 	dsl_dataset_set_compression_arg_t *ddsca = arg;
4519 	dsl_pool_t *dp = dmu_tx_pool(tx);
4520 	dsl_dataset_t *ds = NULL;
4521 
4522 	uint64_t compval = ZIO_COMPRESS_ALGO(ddsca->ddsca_value);
4523 	spa_feature_t f = zio_compress_to_feature(compval);
4524 	ASSERT3S(f, !=, SPA_FEATURE_NONE);
4525 	ASSERT3S(spa_feature_table[f].fi_type, ==, ZFEATURE_TYPE_BOOLEAN);
4526 
4527 	VERIFY0(dsl_dataset_hold(dp, ddsca->ddsca_name, FTAG, &ds));
4528 	if (zfeature_active(f, ds->ds_feature[f]) != B_TRUE) {
4529 		ds->ds_feature_activation[f] = (void *)B_TRUE;
4530 		dsl_dataset_activate_feature(ds->ds_object, f,
4531 		    ds->ds_feature_activation[f], tx);
4532 		ds->ds_feature[f] = ds->ds_feature_activation[f];
4533 	}
4534 	dsl_dataset_rele(ds, FTAG);
4535 }
4536 
4537 int
4538 dsl_dataset_set_compression(const char *dsname, zprop_source_t source,
4539     uint64_t compression)
4540 {
4541 	dsl_dataset_set_compression_arg_t ddsca;
4542 
4543 	/*
4544 	 * The sync task is only required for zstd in order to activate
4545 	 * the feature flag when the property is first set.
4546 	 */
4547 	if (ZIO_COMPRESS_ALGO(compression) != ZIO_COMPRESS_ZSTD)
4548 		return (0);
4549 
4550 	ddsca.ddsca_name = dsname;
4551 	ddsca.ddsca_source = source;
4552 	ddsca.ddsca_value = compression;
4553 
4554 	return (dsl_sync_task(dsname, dsl_dataset_set_compression_check,
4555 	    dsl_dataset_set_compression_sync, &ddsca, 0,
4556 	    ZFS_SPACE_CHECK_EXTRA_RESERVED));
4557 }
4558 
4559 /*
4560  * Return (in *usedp) the amount of space referenced by "new" that was not
4561  * referenced at the time the bookmark corresponds to.  "New" may be a
4562  * snapshot or a head.  The bookmark must be before new, in
4563  * new's filesystem (or its origin) -- caller verifies this.
4564  *
4565  * The written space is calculated by considering two components:  First, we
4566  * ignore any freed space, and calculate the written as new's used space
4567  * minus old's used space.  Next, we add in the amount of space that was freed
4568  * between the two time points, thus reducing new's used space relative to
4569  * old's. Specifically, this is the space that was born before
4570  * zbm_creation_txg, and freed before new (ie. on new's deadlist or a
4571  * previous deadlist).
4572  *
4573  * space freed                         [---------------------]
4574  * snapshots                       ---O-------O--------O-------O------
4575  *                                         bookmark           new
4576  *
4577  * Note, the bookmark's zbm_*_bytes_refd must be valid, but if the HAS_FBN
4578  * flag is not set, we will calculate the freed_before_next based on the
4579  * next snapshot's deadlist, rather than using zbm_*_freed_before_next_snap.
4580  */
4581 static int
4582 dsl_dataset_space_written_impl(zfs_bookmark_phys_t *bmp,
4583     dsl_dataset_t *new, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
4584 {
4585 	int err = 0;
4586 	dsl_pool_t *dp = new->ds_dir->dd_pool;
4587 
4588 	ASSERT(dsl_pool_config_held(dp));
4589 	if (dsl_dataset_is_snapshot(new)) {
4590 		ASSERT3U(bmp->zbm_creation_txg, <,
4591 		    dsl_dataset_phys(new)->ds_creation_txg);
4592 	}
4593 
4594 	*usedp = 0;
4595 	*usedp += dsl_dataset_phys(new)->ds_referenced_bytes;
4596 	*usedp -= bmp->zbm_referenced_bytes_refd;
4597 
4598 	*compp = 0;
4599 	*compp += dsl_dataset_phys(new)->ds_compressed_bytes;
4600 	*compp -= bmp->zbm_compressed_bytes_refd;
4601 
4602 	*uncompp = 0;
4603 	*uncompp += dsl_dataset_phys(new)->ds_uncompressed_bytes;
4604 	*uncompp -= bmp->zbm_uncompressed_bytes_refd;
4605 
4606 	dsl_dataset_t *snap = new;
4607 
4608 	while (dsl_dataset_phys(snap)->ds_prev_snap_txg >
4609 	    bmp->zbm_creation_txg) {
4610 		uint64_t used, comp, uncomp;
4611 
4612 		dsl_deadlist_space_range(&snap->ds_deadlist,
4613 		    0, bmp->zbm_creation_txg,
4614 		    &used, &comp, &uncomp);
4615 		*usedp += used;
4616 		*compp += comp;
4617 		*uncompp += uncomp;
4618 
4619 		uint64_t snapobj = dsl_dataset_phys(snap)->ds_prev_snap_obj;
4620 		if (snap != new)
4621 			dsl_dataset_rele(snap, FTAG);
4622 		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &snap);
4623 		if (err != 0)
4624 			break;
4625 	}
4626 
4627 	/*
4628 	 * We might not have the FBN if we are calculating written from
4629 	 * a snapshot (because we didn't know the correct "next" snapshot
4630 	 * until now).
4631 	 */
4632 	if (bmp->zbm_flags & ZBM_FLAG_HAS_FBN) {
4633 		*usedp += bmp->zbm_referenced_freed_before_next_snap;
4634 		*compp += bmp->zbm_compressed_freed_before_next_snap;
4635 		*uncompp += bmp->zbm_uncompressed_freed_before_next_snap;
4636 	} else {
4637 		ASSERT3U(dsl_dataset_phys(snap)->ds_prev_snap_txg, ==,
4638 		    bmp->zbm_creation_txg);
4639 		uint64_t used, comp, uncomp;
4640 		dsl_deadlist_space(&snap->ds_deadlist, &used, &comp, &uncomp);
4641 		*usedp += used;
4642 		*compp += comp;
4643 		*uncompp += uncomp;
4644 	}
4645 	if (snap != new)
4646 		dsl_dataset_rele(snap, FTAG);
4647 	return (err);
4648 }
4649 
4650 /*
4651  * Return (in *usedp) the amount of space written in new that was not
4652  * present at the time the bookmark corresponds to.  New may be a
4653  * snapshot or the head.  Old must be a bookmark before new, in
4654  * new's filesystem (or its origin) -- caller verifies this.
4655  */
4656 int
4657 dsl_dataset_space_written_bookmark(zfs_bookmark_phys_t *bmp,
4658     dsl_dataset_t *new, uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
4659 {
4660 	if (!(bmp->zbm_flags & ZBM_FLAG_HAS_FBN))
4661 		return (SET_ERROR(ENOTSUP));
4662 	return (dsl_dataset_space_written_impl(bmp, new,
4663 	    usedp, compp, uncompp));
4664 }
4665 
4666 /*
4667  * Return (in *usedp) the amount of space written in new that is not
4668  * present in oldsnap.  New may be a snapshot or the head.  Old must be
4669  * a snapshot before new, in new's filesystem (or its origin).  If not then
4670  * fail and return EINVAL.
4671  */
4672 int
4673 dsl_dataset_space_written(dsl_dataset_t *oldsnap, dsl_dataset_t *new,
4674     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
4675 {
4676 	if (!dsl_dataset_is_before(new, oldsnap, 0))
4677 		return (SET_ERROR(EINVAL));
4678 
4679 	zfs_bookmark_phys_t zbm = { 0 };
4680 	dsl_dataset_phys_t *dsp = dsl_dataset_phys(oldsnap);
4681 	zbm.zbm_guid = dsp->ds_guid;
4682 	zbm.zbm_creation_txg = dsp->ds_creation_txg;
4683 	zbm.zbm_creation_time = dsp->ds_creation_time;
4684 	zbm.zbm_referenced_bytes_refd = dsp->ds_referenced_bytes;
4685 	zbm.zbm_compressed_bytes_refd = dsp->ds_compressed_bytes;
4686 	zbm.zbm_uncompressed_bytes_refd = dsp->ds_uncompressed_bytes;
4687 
4688 	/*
4689 	 * If oldsnap is the origin (or origin's origin, ...) of new,
4690 	 * we can't easily calculate the effective FBN.  Therefore,
4691 	 * we do not set ZBM_FLAG_HAS_FBN, so that the _impl will calculate
4692 	 * it relative to the correct "next": the next snapshot towards "new",
4693 	 * rather than the next snapshot in oldsnap's dsl_dir.
4694 	 */
4695 	return (dsl_dataset_space_written_impl(&zbm, new,
4696 	    usedp, compp, uncompp));
4697 }
4698 
4699 /*
4700  * Return (in *usedp) the amount of space that will be reclaimed if firstsnap,
4701  * lastsnap, and all snapshots in between are deleted.
4702  *
4703  * blocks that would be freed            [---------------------------]
4704  * snapshots                       ---O-------O--------O-------O--------O
4705  *                                        firstsnap        lastsnap
4706  *
4707  * This is the set of blocks that were born after the snap before firstsnap,
4708  * (birth > firstsnap->prev_snap_txg) and died before the snap after the
4709  * last snap (ie, is on lastsnap->ds_next->ds_deadlist or an earlier deadlist).
4710  * We calculate this by iterating over the relevant deadlists (from the snap
4711  * after lastsnap, backward to the snap after firstsnap), summing up the
4712  * space on the deadlist that was born after the snap before firstsnap.
4713  */
4714 int
4715 dsl_dataset_space_wouldfree(dsl_dataset_t *firstsnap,
4716     dsl_dataset_t *lastsnap,
4717     uint64_t *usedp, uint64_t *compp, uint64_t *uncompp)
4718 {
4719 	int err = 0;
4720 	uint64_t snapobj;
4721 	dsl_pool_t *dp = firstsnap->ds_dir->dd_pool;
4722 
4723 	ASSERT(firstsnap->ds_is_snapshot);
4724 	ASSERT(lastsnap->ds_is_snapshot);
4725 
4726 	/*
4727 	 * Check that the snapshots are in the same dsl_dir, and firstsnap
4728 	 * is before lastsnap.
4729 	 */
4730 	if (firstsnap->ds_dir != lastsnap->ds_dir ||
4731 	    dsl_dataset_phys(firstsnap)->ds_creation_txg >
4732 	    dsl_dataset_phys(lastsnap)->ds_creation_txg)
4733 		return (SET_ERROR(EINVAL));
4734 
4735 	*usedp = *compp = *uncompp = 0;
4736 
4737 	snapobj = dsl_dataset_phys(lastsnap)->ds_next_snap_obj;
4738 	while (snapobj != firstsnap->ds_object) {
4739 		dsl_dataset_t *ds;
4740 		uint64_t used, comp, uncomp;
4741 
4742 		err = dsl_dataset_hold_obj(dp, snapobj, FTAG, &ds);
4743 		if (err != 0)
4744 			break;
4745 
4746 		dsl_deadlist_space_range(&ds->ds_deadlist,
4747 		    dsl_dataset_phys(firstsnap)->ds_prev_snap_txg, UINT64_MAX,
4748 		    &used, &comp, &uncomp);
4749 		*usedp += used;
4750 		*compp += comp;
4751 		*uncompp += uncomp;
4752 
4753 		snapobj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
4754 		ASSERT3U(snapobj, !=, 0);
4755 		dsl_dataset_rele(ds, FTAG);
4756 	}
4757 	return (err);
4758 }
4759 
4760 /*
4761  * Return TRUE if 'earlier' is an earlier snapshot in 'later's timeline.
4762  * For example, they could both be snapshots of the same filesystem, and
4763  * 'earlier' is before 'later'.  Or 'earlier' could be the origin of
4764  * 'later's filesystem.  Or 'earlier' could be an older snapshot in the origin's
4765  * filesystem.  Or 'earlier' could be the origin's origin.
4766  *
4767  * If non-zero, earlier_txg is used instead of earlier's ds_creation_txg.
4768  */
4769 boolean_t
4770 dsl_dataset_is_before(dsl_dataset_t *later, dsl_dataset_t *earlier,
4771     uint64_t earlier_txg)
4772 {
4773 	dsl_pool_t *dp = later->ds_dir->dd_pool;
4774 	int error;
4775 	boolean_t ret;
4776 
4777 	ASSERT(dsl_pool_config_held(dp));
4778 	ASSERT(earlier->ds_is_snapshot || earlier_txg != 0);
4779 
4780 	if (earlier_txg == 0)
4781 		earlier_txg = dsl_dataset_phys(earlier)->ds_creation_txg;
4782 
4783 	if (later->ds_is_snapshot &&
4784 	    earlier_txg >= dsl_dataset_phys(later)->ds_creation_txg)
4785 		return (B_FALSE);
4786 
4787 	if (later->ds_dir == earlier->ds_dir)
4788 		return (B_TRUE);
4789 
4790 	/*
4791 	 * We check dd_origin_obj explicitly here rather than using
4792 	 * dsl_dir_is_clone() so that we will return TRUE if "earlier"
4793 	 * is $ORIGIN@$ORIGIN.  dsl_dataset_space_written() depends on
4794 	 * this behavior.
4795 	 */
4796 	if (dsl_dir_phys(later->ds_dir)->dd_origin_obj == 0)
4797 		return (B_FALSE);
4798 
4799 	dsl_dataset_t *origin;
4800 	error = dsl_dataset_hold_obj(dp,
4801 	    dsl_dir_phys(later->ds_dir)->dd_origin_obj, FTAG, &origin);
4802 	if (error != 0)
4803 		return (B_FALSE);
4804 	if (dsl_dataset_phys(origin)->ds_creation_txg == earlier_txg &&
4805 	    origin->ds_dir == earlier->ds_dir) {
4806 		dsl_dataset_rele(origin, FTAG);
4807 		return (B_TRUE);
4808 	}
4809 	ret = dsl_dataset_is_before(origin, earlier, earlier_txg);
4810 	dsl_dataset_rele(origin, FTAG);
4811 	return (ret);
4812 }
4813 
4814 void
4815 dsl_dataset_zapify(dsl_dataset_t *ds, dmu_tx_t *tx)
4816 {
4817 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
4818 	dmu_object_zapify(mos, ds->ds_object, DMU_OT_DSL_DATASET, tx);
4819 }
4820 
4821 boolean_t
4822 dsl_dataset_is_zapified(dsl_dataset_t *ds)
4823 {
4824 	dmu_object_info_t doi;
4825 
4826 	dmu_object_info_from_db(ds->ds_dbuf, &doi);
4827 	return (doi.doi_type == DMU_OTN_ZAP_METADATA);
4828 }
4829 
4830 boolean_t
4831 dsl_dataset_has_resume_receive_state(dsl_dataset_t *ds)
4832 {
4833 	return (dsl_dataset_is_zapified(ds) &&
4834 	    zap_contains(ds->ds_dir->dd_pool->dp_meta_objset,
4835 	    ds->ds_object, DS_FIELD_RESUME_TOGUID) == 0);
4836 }
4837 
4838 uint64_t
4839 dsl_dataset_get_remap_deadlist_object(dsl_dataset_t *ds)
4840 {
4841 	uint64_t remap_deadlist_obj;
4842 	int err;
4843 
4844 	if (!dsl_dataset_is_zapified(ds))
4845 		return (0);
4846 
4847 	err = zap_lookup(ds->ds_dir->dd_pool->dp_meta_objset, ds->ds_object,
4848 	    DS_FIELD_REMAP_DEADLIST, sizeof (remap_deadlist_obj), 1,
4849 	    &remap_deadlist_obj);
4850 
4851 	if (err != 0) {
4852 		VERIFY3S(err, ==, ENOENT);
4853 		return (0);
4854 	}
4855 
4856 	ASSERT(remap_deadlist_obj != 0);
4857 	return (remap_deadlist_obj);
4858 }
4859 
4860 boolean_t
4861 dsl_dataset_remap_deadlist_exists(dsl_dataset_t *ds)
4862 {
4863 	EQUIV(dsl_deadlist_is_open(&ds->ds_remap_deadlist),
4864 	    dsl_dataset_get_remap_deadlist_object(ds) != 0);
4865 	return (dsl_deadlist_is_open(&ds->ds_remap_deadlist));
4866 }
4867 
4868 static void
4869 dsl_dataset_set_remap_deadlist_object(dsl_dataset_t *ds, uint64_t obj,
4870     dmu_tx_t *tx)
4871 {
4872 	ASSERT(obj != 0);
4873 	dsl_dataset_zapify(ds, tx);
4874 	VERIFY0(zap_add(ds->ds_dir->dd_pool->dp_meta_objset, ds->ds_object,
4875 	    DS_FIELD_REMAP_DEADLIST, sizeof (obj), 1, &obj, tx));
4876 }
4877 
4878 static void
4879 dsl_dataset_unset_remap_deadlist_object(dsl_dataset_t *ds, dmu_tx_t *tx)
4880 {
4881 	VERIFY0(zap_remove(ds->ds_dir->dd_pool->dp_meta_objset,
4882 	    ds->ds_object, DS_FIELD_REMAP_DEADLIST, tx));
4883 }
4884 
4885 void
4886 dsl_dataset_destroy_remap_deadlist(dsl_dataset_t *ds, dmu_tx_t *tx)
4887 {
4888 	uint64_t remap_deadlist_object;
4889 	spa_t *spa = ds->ds_dir->dd_pool->dp_spa;
4890 
4891 	ASSERT(dmu_tx_is_syncing(tx));
4892 	ASSERT(dsl_dataset_remap_deadlist_exists(ds));
4893 
4894 	remap_deadlist_object = ds->ds_remap_deadlist.dl_object;
4895 	dsl_deadlist_close(&ds->ds_remap_deadlist);
4896 	dsl_deadlist_free(spa_meta_objset(spa), remap_deadlist_object, tx);
4897 	dsl_dataset_unset_remap_deadlist_object(ds, tx);
4898 	spa_feature_decr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
4899 }
4900 
4901 void
4902 dsl_dataset_create_remap_deadlist(dsl_dataset_t *ds, dmu_tx_t *tx)
4903 {
4904 	uint64_t remap_deadlist_obj;
4905 	spa_t *spa = ds->ds_dir->dd_pool->dp_spa;
4906 
4907 	ASSERT(dmu_tx_is_syncing(tx));
4908 	ASSERT(MUTEX_HELD(&ds->ds_remap_deadlist_lock));
4909 	/*
4910 	 * Currently we only create remap deadlists when there are indirect
4911 	 * vdevs with referenced mappings.
4912 	 */
4913 	ASSERT(spa_feature_is_active(spa, SPA_FEATURE_DEVICE_REMOVAL));
4914 
4915 	remap_deadlist_obj = dsl_deadlist_clone(
4916 	    &ds->ds_deadlist, UINT64_MAX,
4917 	    dsl_dataset_phys(ds)->ds_prev_snap_obj, tx);
4918 	dsl_dataset_set_remap_deadlist_object(ds,
4919 	    remap_deadlist_obj, tx);
4920 	dsl_deadlist_open(&ds->ds_remap_deadlist, spa_meta_objset(spa),
4921 	    remap_deadlist_obj);
4922 	spa_feature_incr(spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
4923 }
4924 
4925 void
4926 dsl_dataset_activate_redaction(dsl_dataset_t *ds, uint64_t *redact_snaps,
4927     uint64_t num_redact_snaps, dmu_tx_t *tx)
4928 {
4929 	uint64_t dsobj = ds->ds_object;
4930 	struct feature_type_uint64_array_arg *ftuaa =
4931 	    kmem_zalloc(sizeof (*ftuaa), KM_SLEEP);
4932 	ftuaa->length = (int64_t)num_redact_snaps;
4933 	if (num_redact_snaps > 0) {
4934 		ftuaa->array = kmem_alloc(num_redact_snaps * sizeof (uint64_t),
4935 		    KM_SLEEP);
4936 		memcpy(ftuaa->array, redact_snaps, num_redact_snaps *
4937 		    sizeof (uint64_t));
4938 	}
4939 	dsl_dataset_activate_feature(dsobj, SPA_FEATURE_REDACTED_DATASETS,
4940 	    ftuaa, tx);
4941 	ds->ds_feature[SPA_FEATURE_REDACTED_DATASETS] = ftuaa;
4942 }
4943 
4944 /*
4945  * Find and return (in *oldest_dsobj) the oldest snapshot of the dsobj
4946  * dataset whose birth time is >= min_txg.
4947  */
4948 int
4949 dsl_dataset_oldest_snapshot(spa_t *spa, uint64_t head_ds, uint64_t min_txg,
4950     uint64_t *oldest_dsobj)
4951 {
4952 	dsl_dataset_t *ds;
4953 	dsl_pool_t *dp = spa->spa_dsl_pool;
4954 
4955 	int error = dsl_dataset_hold_obj(dp, head_ds, FTAG, &ds);
4956 	if (error != 0)
4957 		return (error);
4958 
4959 	uint64_t prev_obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
4960 	uint64_t prev_obj_txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
4961 
4962 	while (prev_obj != 0 && min_txg < prev_obj_txg) {
4963 		dsl_dataset_rele(ds, FTAG);
4964 		if ((error = dsl_dataset_hold_obj(dp, prev_obj,
4965 		    FTAG, &ds)) != 0)
4966 			return (error);
4967 		prev_obj_txg = dsl_dataset_phys(ds)->ds_prev_snap_txg;
4968 		prev_obj = dsl_dataset_phys(ds)->ds_prev_snap_obj;
4969 	}
4970 	*oldest_dsobj = ds->ds_object;
4971 	dsl_dataset_rele(ds, FTAG);
4972 	return (0);
4973 }
4974 
4975 ZFS_MODULE_PARAM(zfs, zfs_, max_recordsize, UINT, ZMOD_RW,
4976 	"Max allowed record size");
4977 
4978 ZFS_MODULE_PARAM(zfs, zfs_, allow_redacted_dataset_mount, INT, ZMOD_RW,
4979 	"Allow mounting of redacted datasets");
4980 
4981 ZFS_MODULE_PARAM(zfs, zfs_, snapshot_history_enabled, INT, ZMOD_RW,
4982 	"Include snapshot events in pool history/events");
4983 
4984 EXPORT_SYMBOL(dsl_dataset_hold);
4985 EXPORT_SYMBOL(dsl_dataset_hold_flags);
4986 EXPORT_SYMBOL(dsl_dataset_hold_obj);
4987 EXPORT_SYMBOL(dsl_dataset_hold_obj_flags);
4988 EXPORT_SYMBOL(dsl_dataset_own);
4989 EXPORT_SYMBOL(dsl_dataset_own_obj);
4990 EXPORT_SYMBOL(dsl_dataset_name);
4991 EXPORT_SYMBOL(dsl_dataset_rele);
4992 EXPORT_SYMBOL(dsl_dataset_rele_flags);
4993 EXPORT_SYMBOL(dsl_dataset_disown);
4994 EXPORT_SYMBOL(dsl_dataset_tryown);
4995 EXPORT_SYMBOL(dsl_dataset_create_sync);
4996 EXPORT_SYMBOL(dsl_dataset_create_sync_dd);
4997 EXPORT_SYMBOL(dsl_dataset_snapshot_check);
4998 EXPORT_SYMBOL(dsl_dataset_snapshot_sync);
4999 EXPORT_SYMBOL(dsl_dataset_promote);
5000 EXPORT_SYMBOL(dsl_dataset_user_hold);
5001 EXPORT_SYMBOL(dsl_dataset_user_release);
5002 EXPORT_SYMBOL(dsl_dataset_get_holds);
5003 EXPORT_SYMBOL(dsl_dataset_get_blkptr);
5004 EXPORT_SYMBOL(dsl_dataset_get_spa);
5005 EXPORT_SYMBOL(dsl_dataset_modified_since_snap);
5006 EXPORT_SYMBOL(dsl_dataset_space_written);
5007 EXPORT_SYMBOL(dsl_dataset_space_wouldfree);
5008 EXPORT_SYMBOL(dsl_dataset_sync);
5009 EXPORT_SYMBOL(dsl_dataset_block_born);
5010 EXPORT_SYMBOL(dsl_dataset_block_kill);
5011 EXPORT_SYMBOL(dsl_dataset_dirty);
5012 EXPORT_SYMBOL(dsl_dataset_stats);
5013 EXPORT_SYMBOL(dsl_dataset_fast_stat);
5014 EXPORT_SYMBOL(dsl_dataset_space);
5015 EXPORT_SYMBOL(dsl_dataset_fsid_guid);
5016 EXPORT_SYMBOL(dsl_dsobj_to_dsname);
5017 EXPORT_SYMBOL(dsl_dataset_check_quota);
5018 EXPORT_SYMBOL(dsl_dataset_clone_swap_check_impl);
5019 EXPORT_SYMBOL(dsl_dataset_clone_swap_sync_impl);
5020