xref: /titanic_41/usr/src/uts/common/fs/zfs/dsl_destroy.c (revision a7e97b3048398e7eddf8046350d83af094a1d6bd)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2012, 2015 by Delphix. All rights reserved.
24  * Copyright (c) 2013 Steven Hartland. All rights reserved.
25  * Copyright (c) 2013 by Joyent, Inc. All rights reserved.
26  */
27 
28 #include <sys/zfs_context.h>
29 #include <sys/dsl_userhold.h>
30 #include <sys/dsl_dataset.h>
31 #include <sys/dsl_synctask.h>
32 #include <sys/dmu_tx.h>
33 #include <sys/dsl_pool.h>
34 #include <sys/dsl_dir.h>
35 #include <sys/dmu_traverse.h>
36 #include <sys/dsl_scan.h>
37 #include <sys/dmu_objset.h>
38 #include <sys/zap.h>
39 #include <sys/zfeature.h>
40 #include <sys/zfs_ioctl.h>
41 #include <sys/dsl_deleg.h>
42 #include <sys/dmu_impl.h>
43 
44 typedef struct dmu_snapshots_destroy_arg {
45 	nvlist_t *dsda_snaps;
46 	nvlist_t *dsda_successful_snaps;
47 	boolean_t dsda_defer;
48 	nvlist_t *dsda_errlist;
49 } dmu_snapshots_destroy_arg_t;
50 
51 int
dsl_destroy_snapshot_check_impl(dsl_dataset_t * ds,boolean_t defer)52 dsl_destroy_snapshot_check_impl(dsl_dataset_t *ds, boolean_t defer)
53 {
54 	if (!ds->ds_is_snapshot)
55 		return (SET_ERROR(EINVAL));
56 
57 	if (dsl_dataset_long_held(ds))
58 		return (SET_ERROR(EBUSY));
59 
60 	/*
61 	 * Only allow deferred destroy on pools that support it.
62 	 * NOTE: deferred destroy is only supported on snapshots.
63 	 */
64 	if (defer) {
65 		if (spa_version(ds->ds_dir->dd_pool->dp_spa) <
66 		    SPA_VERSION_USERREFS)
67 			return (SET_ERROR(ENOTSUP));
68 		return (0);
69 	}
70 
71 	/*
72 	 * If this snapshot has an elevated user reference count,
73 	 * we can't destroy it yet.
74 	 */
75 	if (ds->ds_userrefs > 0)
76 		return (SET_ERROR(EBUSY));
77 
78 	/*
79 	 * Can't delete a branch point.
80 	 */
81 	if (dsl_dataset_phys(ds)->ds_num_children > 1)
82 		return (SET_ERROR(EEXIST));
83 
84 	return (0);
85 }
86 
87 static int
dsl_destroy_snapshot_check(void * arg,dmu_tx_t * tx)88 dsl_destroy_snapshot_check(void *arg, dmu_tx_t *tx)
89 {
90 	dmu_snapshots_destroy_arg_t *dsda = arg;
91 	dsl_pool_t *dp = dmu_tx_pool(tx);
92 	nvpair_t *pair;
93 	int error = 0;
94 
95 	if (!dmu_tx_is_syncing(tx))
96 		return (0);
97 
98 	for (pair = nvlist_next_nvpair(dsda->dsda_snaps, NULL);
99 	    pair != NULL; pair = nvlist_next_nvpair(dsda->dsda_snaps, pair)) {
100 		dsl_dataset_t *ds;
101 
102 		error = dsl_dataset_hold(dp, nvpair_name(pair),
103 		    FTAG, &ds);
104 
105 		/*
106 		 * If the snapshot does not exist, silently ignore it
107 		 * (it's "already destroyed").
108 		 */
109 		if (error == ENOENT)
110 			continue;
111 
112 		if (error == 0) {
113 			error = dsl_destroy_snapshot_check_impl(ds,
114 			    dsda->dsda_defer);
115 			dsl_dataset_rele(ds, FTAG);
116 		}
117 
118 		if (error == 0) {
119 			fnvlist_add_boolean(dsda->dsda_successful_snaps,
120 			    nvpair_name(pair));
121 		} else {
122 			fnvlist_add_int32(dsda->dsda_errlist,
123 			    nvpair_name(pair), error);
124 		}
125 	}
126 
127 	pair = nvlist_next_nvpair(dsda->dsda_errlist, NULL);
128 	if (pair != NULL)
129 		return (fnvpair_value_int32(pair));
130 
131 	return (0);
132 }
133 
134 struct process_old_arg {
135 	dsl_dataset_t *ds;
136 	dsl_dataset_t *ds_prev;
137 	boolean_t after_branch_point;
138 	zio_t *pio;
139 	uint64_t used, comp, uncomp;
140 };
141 
142 static int
process_old_cb(void * arg,const blkptr_t * bp,dmu_tx_t * tx)143 process_old_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
144 {
145 	struct process_old_arg *poa = arg;
146 	dsl_pool_t *dp = poa->ds->ds_dir->dd_pool;
147 
148 	ASSERT(!BP_IS_HOLE(bp));
149 
150 	if (bp->blk_birth <= dsl_dataset_phys(poa->ds)->ds_prev_snap_txg) {
151 		dsl_deadlist_insert(&poa->ds->ds_deadlist, bp, tx);
152 		if (poa->ds_prev && !poa->after_branch_point &&
153 		    bp->blk_birth >
154 		    dsl_dataset_phys(poa->ds_prev)->ds_prev_snap_txg) {
155 			dsl_dataset_phys(poa->ds_prev)->ds_unique_bytes +=
156 			    bp_get_dsize_sync(dp->dp_spa, bp);
157 		}
158 	} else {
159 		poa->used += bp_get_dsize_sync(dp->dp_spa, bp);
160 		poa->comp += BP_GET_PSIZE(bp);
161 		poa->uncomp += BP_GET_UCSIZE(bp);
162 		dsl_free_sync(poa->pio, dp, tx->tx_txg, bp);
163 	}
164 	return (0);
165 }
166 
167 static void
process_old_deadlist(dsl_dataset_t * ds,dsl_dataset_t * ds_prev,dsl_dataset_t * ds_next,boolean_t after_branch_point,dmu_tx_t * tx)168 process_old_deadlist(dsl_dataset_t *ds, dsl_dataset_t *ds_prev,
169     dsl_dataset_t *ds_next, boolean_t after_branch_point, dmu_tx_t *tx)
170 {
171 	struct process_old_arg poa = { 0 };
172 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
173 	objset_t *mos = dp->dp_meta_objset;
174 	uint64_t deadlist_obj;
175 
176 	ASSERT(ds->ds_deadlist.dl_oldfmt);
177 	ASSERT(ds_next->ds_deadlist.dl_oldfmt);
178 
179 	poa.ds = ds;
180 	poa.ds_prev = ds_prev;
181 	poa.after_branch_point = after_branch_point;
182 	poa.pio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
183 	VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
184 	    process_old_cb, &poa, tx));
185 	VERIFY0(zio_wait(poa.pio));
186 	ASSERT3U(poa.used, ==, dsl_dataset_phys(ds)->ds_unique_bytes);
187 
188 	/* change snapused */
189 	dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
190 	    -poa.used, -poa.comp, -poa.uncomp, tx);
191 
192 	/* swap next's deadlist to our deadlist */
193 	dsl_deadlist_close(&ds->ds_deadlist);
194 	dsl_deadlist_close(&ds_next->ds_deadlist);
195 	deadlist_obj = dsl_dataset_phys(ds)->ds_deadlist_obj;
196 	dsl_dataset_phys(ds)->ds_deadlist_obj =
197 	    dsl_dataset_phys(ds_next)->ds_deadlist_obj;
198 	dsl_dataset_phys(ds_next)->ds_deadlist_obj = deadlist_obj;
199 	dsl_deadlist_open(&ds->ds_deadlist, mos,
200 	    dsl_dataset_phys(ds)->ds_deadlist_obj);
201 	dsl_deadlist_open(&ds_next->ds_deadlist, mos,
202 	    dsl_dataset_phys(ds_next)->ds_deadlist_obj);
203 }
204 
205 static void
dsl_dataset_remove_clones_key(dsl_dataset_t * ds,uint64_t mintxg,dmu_tx_t * tx)206 dsl_dataset_remove_clones_key(dsl_dataset_t *ds, uint64_t mintxg, dmu_tx_t *tx)
207 {
208 	objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
209 	zap_cursor_t zc;
210 	zap_attribute_t za;
211 
212 	/*
213 	 * If it is the old version, dd_clones doesn't exist so we can't
214 	 * find the clones, but dsl_deadlist_remove_key() is a no-op so it
215 	 * doesn't matter.
216 	 */
217 	if (dsl_dir_phys(ds->ds_dir)->dd_clones == 0)
218 		return;
219 
220 	for (zap_cursor_init(&zc, mos, dsl_dir_phys(ds->ds_dir)->dd_clones);
221 	    zap_cursor_retrieve(&zc, &za) == 0;
222 	    zap_cursor_advance(&zc)) {
223 		dsl_dataset_t *clone;
224 
225 		VERIFY0(dsl_dataset_hold_obj(ds->ds_dir->dd_pool,
226 		    za.za_first_integer, FTAG, &clone));
227 		if (clone->ds_dir->dd_origin_txg > mintxg) {
228 			dsl_deadlist_remove_key(&clone->ds_deadlist,
229 			    mintxg, tx);
230 			dsl_dataset_remove_clones_key(clone, mintxg, tx);
231 		}
232 		dsl_dataset_rele(clone, FTAG);
233 	}
234 	zap_cursor_fini(&zc);
235 }
236 
237 void
dsl_destroy_snapshot_sync_impl(dsl_dataset_t * ds,boolean_t defer,dmu_tx_t * tx)238 dsl_destroy_snapshot_sync_impl(dsl_dataset_t *ds, boolean_t defer, dmu_tx_t *tx)
239 {
240 	int err;
241 	int after_branch_point = FALSE;
242 	dsl_pool_t *dp = ds->ds_dir->dd_pool;
243 	objset_t *mos = dp->dp_meta_objset;
244 	dsl_dataset_t *ds_prev = NULL;
245 	uint64_t obj;
246 
247 	ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
248 	ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
249 	ASSERT(refcount_is_zero(&ds->ds_longholds));
250 
251 	if (defer &&
252 	    (ds->ds_userrefs > 0 ||
253 	    dsl_dataset_phys(ds)->ds_num_children > 1)) {
254 		ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
255 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
256 		dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_DEFER_DESTROY;
257 		spa_history_log_internal_ds(ds, "defer_destroy", tx, "");
258 		return;
259 	}
260 
261 	ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
262 
263 	/* We need to log before removing it from the namespace. */
264 	spa_history_log_internal_ds(ds, "destroy", tx, "");
265 
266 	dsl_scan_ds_destroyed(ds, tx);
267 
268 	obj = ds->ds_object;
269 
270 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
271 		if (ds->ds_feature_inuse[f]) {
272 			dsl_dataset_deactivate_feature(obj, f, tx);
273 			ds->ds_feature_inuse[f] = B_FALSE;
274 		}
275 	}
276 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
277 		ASSERT3P(ds->ds_prev, ==, NULL);
278 		VERIFY0(dsl_dataset_hold_obj(dp,
279 		    dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &ds_prev));
280 		after_branch_point =
281 		    (dsl_dataset_phys(ds_prev)->ds_next_snap_obj != obj);
282 
283 		dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
284 		if (after_branch_point &&
285 		    dsl_dataset_phys(ds_prev)->ds_next_clones_obj != 0) {
286 			dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
287 			if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
288 				VERIFY0(zap_add_int(mos,
289 				    dsl_dataset_phys(ds_prev)->
290 				    ds_next_clones_obj,
291 				    dsl_dataset_phys(ds)->ds_next_snap_obj,
292 				    tx));
293 			}
294 		}
295 		if (!after_branch_point) {
296 			dsl_dataset_phys(ds_prev)->ds_next_snap_obj =
297 			    dsl_dataset_phys(ds)->ds_next_snap_obj;
298 		}
299 	}
300 
301 	dsl_dataset_t *ds_next;
302 	uint64_t old_unique;
303 	uint64_t used = 0, comp = 0, uncomp = 0;
304 
305 	VERIFY0(dsl_dataset_hold_obj(dp,
306 	    dsl_dataset_phys(ds)->ds_next_snap_obj, FTAG, &ds_next));
307 	ASSERT3U(dsl_dataset_phys(ds_next)->ds_prev_snap_obj, ==, obj);
308 
309 	old_unique = dsl_dataset_phys(ds_next)->ds_unique_bytes;
310 
311 	dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
312 	dsl_dataset_phys(ds_next)->ds_prev_snap_obj =
313 	    dsl_dataset_phys(ds)->ds_prev_snap_obj;
314 	dsl_dataset_phys(ds_next)->ds_prev_snap_txg =
315 	    dsl_dataset_phys(ds)->ds_prev_snap_txg;
316 	ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
317 	    ds_prev ? dsl_dataset_phys(ds_prev)->ds_creation_txg : 0);
318 
319 	if (ds_next->ds_deadlist.dl_oldfmt) {
320 		process_old_deadlist(ds, ds_prev, ds_next,
321 		    after_branch_point, tx);
322 	} else {
323 		/* Adjust prev's unique space. */
324 		if (ds_prev && !after_branch_point) {
325 			dsl_deadlist_space_range(&ds_next->ds_deadlist,
326 			    dsl_dataset_phys(ds_prev)->ds_prev_snap_txg,
327 			    dsl_dataset_phys(ds)->ds_prev_snap_txg,
328 			    &used, &comp, &uncomp);
329 			dsl_dataset_phys(ds_prev)->ds_unique_bytes += used;
330 		}
331 
332 		/* Adjust snapused. */
333 		dsl_deadlist_space_range(&ds_next->ds_deadlist,
334 		    dsl_dataset_phys(ds)->ds_prev_snap_txg, UINT64_MAX,
335 		    &used, &comp, &uncomp);
336 		dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
337 		    -used, -comp, -uncomp, tx);
338 
339 		/* Move blocks to be freed to pool's free list. */
340 		dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
341 		    &dp->dp_free_bpobj, dsl_dataset_phys(ds)->ds_prev_snap_txg,
342 		    tx);
343 		dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
344 		    DD_USED_HEAD, used, comp, uncomp, tx);
345 
346 		/* Merge our deadlist into next's and free it. */
347 		dsl_deadlist_merge(&ds_next->ds_deadlist,
348 		    dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
349 	}
350 	dsl_deadlist_close(&ds->ds_deadlist);
351 	dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
352 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
353 	dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
354 
355 	/* Collapse range in clone heads */
356 	dsl_dataset_remove_clones_key(ds,
357 	    dsl_dataset_phys(ds)->ds_creation_txg, tx);
358 
359 	if (ds_next->ds_is_snapshot) {
360 		dsl_dataset_t *ds_nextnext;
361 
362 		/*
363 		 * Update next's unique to include blocks which
364 		 * were previously shared by only this snapshot
365 		 * and it.  Those blocks will be born after the
366 		 * prev snap and before this snap, and will have
367 		 * died after the next snap and before the one
368 		 * after that (ie. be on the snap after next's
369 		 * deadlist).
370 		 */
371 		VERIFY0(dsl_dataset_hold_obj(dp,
372 		    dsl_dataset_phys(ds_next)->ds_next_snap_obj,
373 		    FTAG, &ds_nextnext));
374 		dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
375 		    dsl_dataset_phys(ds)->ds_prev_snap_txg,
376 		    dsl_dataset_phys(ds)->ds_creation_txg,
377 		    &used, &comp, &uncomp);
378 		dsl_dataset_phys(ds_next)->ds_unique_bytes += used;
379 		dsl_dataset_rele(ds_nextnext, FTAG);
380 		ASSERT3P(ds_next->ds_prev, ==, NULL);
381 
382 		/* Collapse range in this head. */
383 		dsl_dataset_t *hds;
384 		VERIFY0(dsl_dataset_hold_obj(dp,
385 		    dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &hds));
386 		dsl_deadlist_remove_key(&hds->ds_deadlist,
387 		    dsl_dataset_phys(ds)->ds_creation_txg, tx);
388 		dsl_dataset_rele(hds, FTAG);
389 
390 	} else {
391 		ASSERT3P(ds_next->ds_prev, ==, ds);
392 		dsl_dataset_rele(ds_next->ds_prev, ds_next);
393 		ds_next->ds_prev = NULL;
394 		if (ds_prev) {
395 			VERIFY0(dsl_dataset_hold_obj(dp,
396 			    dsl_dataset_phys(ds)->ds_prev_snap_obj,
397 			    ds_next, &ds_next->ds_prev));
398 		}
399 
400 		dsl_dataset_recalc_head_uniq(ds_next);
401 
402 		/*
403 		 * Reduce the amount of our unconsumed refreservation
404 		 * being charged to our parent by the amount of
405 		 * new unique data we have gained.
406 		 */
407 		if (old_unique < ds_next->ds_reserved) {
408 			int64_t mrsdelta;
409 			uint64_t new_unique =
410 			    dsl_dataset_phys(ds_next)->ds_unique_bytes;
411 
412 			ASSERT(old_unique <= new_unique);
413 			mrsdelta = MIN(new_unique - old_unique,
414 			    ds_next->ds_reserved - old_unique);
415 			dsl_dir_diduse_space(ds->ds_dir,
416 			    DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
417 		}
418 	}
419 	dsl_dataset_rele(ds_next, FTAG);
420 
421 	/*
422 	 * This must be done after the dsl_traverse(), because it will
423 	 * re-open the objset.
424 	 */
425 	if (ds->ds_objset) {
426 		dmu_objset_evict(ds->ds_objset);
427 		ds->ds_objset = NULL;
428 	}
429 
430 	/* remove from snapshot namespace */
431 	dsl_dataset_t *ds_head;
432 	ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0);
433 	VERIFY0(dsl_dataset_hold_obj(dp,
434 	    dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &ds_head));
435 	VERIFY0(dsl_dataset_get_snapname(ds));
436 #ifdef ZFS_DEBUG
437 	{
438 		uint64_t val;
439 
440 		err = dsl_dataset_snap_lookup(ds_head,
441 		    ds->ds_snapname, &val);
442 		ASSERT0(err);
443 		ASSERT3U(val, ==, obj);
444 	}
445 #endif
446 	VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx, B_TRUE));
447 	dsl_dataset_rele(ds_head, FTAG);
448 
449 	if (ds_prev != NULL)
450 		dsl_dataset_rele(ds_prev, FTAG);
451 
452 	spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
453 
454 	if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
455 		uint64_t count;
456 		ASSERT0(zap_count(mos,
457 		    dsl_dataset_phys(ds)->ds_next_clones_obj, &count) &&
458 		    count == 0);
459 		VERIFY0(dmu_object_free(mos,
460 		    dsl_dataset_phys(ds)->ds_next_clones_obj, tx));
461 	}
462 	if (dsl_dataset_phys(ds)->ds_props_obj != 0)
463 		VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_props_obj,
464 		    tx));
465 	if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0)
466 		VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
467 		    tx));
468 	dsl_dir_rele(ds->ds_dir, ds);
469 	ds->ds_dir = NULL;
470 	dmu_object_free_zapified(mos, obj, tx);
471 }
472 
473 static void
dsl_destroy_snapshot_sync(void * arg,dmu_tx_t * tx)474 dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
475 {
476 	dmu_snapshots_destroy_arg_t *dsda = arg;
477 	dsl_pool_t *dp = dmu_tx_pool(tx);
478 	nvpair_t *pair;
479 
480 	for (pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, NULL);
481 	    pair != NULL;
482 	    pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, pair)) {
483 		dsl_dataset_t *ds;
484 
485 		VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
486 
487 		dsl_destroy_snapshot_sync_impl(ds, dsda->dsda_defer, tx);
488 		dsl_dataset_rele(ds, FTAG);
489 	}
490 }
491 
492 /*
493  * The semantics of this function are described in the comment above
494  * lzc_destroy_snaps().  To summarize:
495  *
496  * The snapshots must all be in the same pool.
497  *
498  * Snapshots that don't exist will be silently ignored (considered to be
499  * "already deleted").
500  *
501  * On success, all snaps will be destroyed and this will return 0.
502  * On failure, no snaps will be destroyed, the errlist will be filled in,
503  * and this will return an errno.
504  */
505 int
dsl_destroy_snapshots_nvl(nvlist_t * snaps,boolean_t defer,nvlist_t * errlist)506 dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
507     nvlist_t *errlist)
508 {
509 	dmu_snapshots_destroy_arg_t dsda;
510 	int error;
511 	nvpair_t *pair;
512 
513 	pair = nvlist_next_nvpair(snaps, NULL);
514 	if (pair == NULL)
515 		return (0);
516 
517 	dsda.dsda_snaps = snaps;
518 	dsda.dsda_successful_snaps = fnvlist_alloc();
519 	dsda.dsda_defer = defer;
520 	dsda.dsda_errlist = errlist;
521 
522 	error = dsl_sync_task(nvpair_name(pair),
523 	    dsl_destroy_snapshot_check, dsl_destroy_snapshot_sync,
524 	    &dsda, 0, ZFS_SPACE_CHECK_NONE);
525 	fnvlist_free(dsda.dsda_successful_snaps);
526 
527 	return (error);
528 }
529 
530 int
dsl_destroy_snapshot(const char * name,boolean_t defer)531 dsl_destroy_snapshot(const char *name, boolean_t defer)
532 {
533 	int error;
534 	nvlist_t *nvl = fnvlist_alloc();
535 	nvlist_t *errlist = fnvlist_alloc();
536 
537 	fnvlist_add_boolean(nvl, name);
538 	error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
539 	fnvlist_free(errlist);
540 	fnvlist_free(nvl);
541 	return (error);
542 }
543 
544 struct killarg {
545 	dsl_dataset_t *ds;
546 	dmu_tx_t *tx;
547 };
548 
549 /* ARGSUSED */
550 static int
kill_blkptr(spa_t * spa,zilog_t * zilog,const blkptr_t * bp,const zbookmark_phys_t * zb,const dnode_phys_t * dnp,void * arg)551 kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
552     const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
553 {
554 	struct killarg *ka = arg;
555 	dmu_tx_t *tx = ka->tx;
556 
557 	if (bp == NULL || BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
558 		return (0);
559 
560 	if (zb->zb_level == ZB_ZIL_LEVEL) {
561 		ASSERT(zilog != NULL);
562 		/*
563 		 * It's a block in the intent log.  It has no
564 		 * accounting, so just free it.
565 		 */
566 		dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
567 	} else {
568 		ASSERT(zilog == NULL);
569 		ASSERT3U(bp->blk_birth, >,
570 		    dsl_dataset_phys(ka->ds)->ds_prev_snap_txg);
571 		(void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
572 	}
573 
574 	return (0);
575 }
576 
577 static void
old_synchronous_dataset_destroy(dsl_dataset_t * ds,dmu_tx_t * tx)578 old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
579 {
580 	struct killarg ka;
581 
582 	/*
583 	 * Free everything that we point to (that's born after
584 	 * the previous snapshot, if we are a clone)
585 	 *
586 	 * NB: this should be very quick, because we already
587 	 * freed all the objects in open context.
588 	 */
589 	ka.ds = ds;
590 	ka.tx = tx;
591 	VERIFY0(traverse_dataset(ds,
592 	    dsl_dataset_phys(ds)->ds_prev_snap_txg, TRAVERSE_POST,
593 	    kill_blkptr, &ka));
594 	ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
595 	    dsl_dataset_phys(ds)->ds_unique_bytes == 0);
596 }
597 
598 typedef struct dsl_destroy_head_arg {
599 	const char *ddha_name;
600 } dsl_destroy_head_arg_t;
601 
602 int
dsl_destroy_head_check_impl(dsl_dataset_t * ds,int expected_holds)603 dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
604 {
605 	int error;
606 	uint64_t count;
607 	objset_t *mos;
608 
609 	ASSERT(!ds->ds_is_snapshot);
610 	if (ds->ds_is_snapshot)
611 		return (SET_ERROR(EINVAL));
612 
613 	if (refcount_count(&ds->ds_longholds) != expected_holds)
614 		return (SET_ERROR(EBUSY));
615 
616 	mos = ds->ds_dir->dd_pool->dp_meta_objset;
617 
618 	/*
619 	 * Can't delete a head dataset if there are snapshots of it.
620 	 * (Except if the only snapshots are from the branch we cloned
621 	 * from.)
622 	 */
623 	if (ds->ds_prev != NULL &&
624 	    dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj == ds->ds_object)
625 		return (SET_ERROR(EBUSY));
626 
627 	/*
628 	 * Can't delete if there are children of this fs.
629 	 */
630 	error = zap_count(mos,
631 	    dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, &count);
632 	if (error != 0)
633 		return (error);
634 	if (count != 0)
635 		return (SET_ERROR(EEXIST));
636 
637 	if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
638 	    dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
639 	    ds->ds_prev->ds_userrefs == 0) {
640 		/* We need to remove the origin snapshot as well. */
641 		if (!refcount_is_zero(&ds->ds_prev->ds_longholds))
642 			return (SET_ERROR(EBUSY));
643 	}
644 	return (0);
645 }
646 
647 static int
dsl_destroy_head_check(void * arg,dmu_tx_t * tx)648 dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
649 {
650 	dsl_destroy_head_arg_t *ddha = arg;
651 	dsl_pool_t *dp = dmu_tx_pool(tx);
652 	dsl_dataset_t *ds;
653 	int error;
654 
655 	error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
656 	if (error != 0)
657 		return (error);
658 
659 	error = dsl_destroy_head_check_impl(ds, 0);
660 	dsl_dataset_rele(ds, FTAG);
661 	return (error);
662 }
663 
664 static void
dsl_dir_destroy_sync(uint64_t ddobj,dmu_tx_t * tx)665 dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
666 {
667 	dsl_dir_t *dd;
668 	dsl_pool_t *dp = dmu_tx_pool(tx);
669 	objset_t *mos = dp->dp_meta_objset;
670 	dd_used_t t;
671 
672 	ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
673 
674 	VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
675 
676 	ASSERT0(dsl_dir_phys(dd)->dd_head_dataset_obj);
677 
678 	/*
679 	 * Decrement the filesystem count for all parent filesystems.
680 	 *
681 	 * When we receive an incremental stream into a filesystem that already
682 	 * exists, a temporary clone is created.  We never count this temporary
683 	 * clone, whose name begins with a '%'.
684 	 */
685 	if (dd->dd_myname[0] != '%' && dd->dd_parent != NULL)
686 		dsl_fs_ss_count_adjust(dd->dd_parent, -1,
687 		    DD_FIELD_FILESYSTEM_COUNT, tx);
688 
689 	/*
690 	 * Remove our reservation. The impl() routine avoids setting the
691 	 * actual property, which would require the (already destroyed) ds.
692 	 */
693 	dsl_dir_set_reservation_sync_impl(dd, 0, tx);
694 
695 	ASSERT0(dsl_dir_phys(dd)->dd_used_bytes);
696 	ASSERT0(dsl_dir_phys(dd)->dd_reserved);
697 	for (t = 0; t < DD_USED_NUM; t++)
698 		ASSERT0(dsl_dir_phys(dd)->dd_used_breakdown[t]);
699 
700 	VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_child_dir_zapobj, tx));
701 	VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_props_zapobj, tx));
702 	VERIFY0(dsl_deleg_destroy(mos, dsl_dir_phys(dd)->dd_deleg_zapobj, tx));
703 	VERIFY0(zap_remove(mos,
704 	    dsl_dir_phys(dd->dd_parent)->dd_child_dir_zapobj,
705 	    dd->dd_myname, tx));
706 
707 	dsl_dir_rele(dd, FTAG);
708 	dmu_object_free_zapified(mos, ddobj, tx);
709 }
710 
711 void
dsl_destroy_head_sync_impl(dsl_dataset_t * ds,dmu_tx_t * tx)712 dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
713 {
714 	dsl_pool_t *dp = dmu_tx_pool(tx);
715 	objset_t *mos = dp->dp_meta_objset;
716 	uint64_t obj, ddobj, prevobj = 0;
717 	boolean_t rmorigin;
718 
719 	ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
720 	ASSERT(ds->ds_prev == NULL ||
721 	    dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj != ds->ds_object);
722 	ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
723 	ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
724 
725 	/* We need to log before removing it from the namespace. */
726 	spa_history_log_internal_ds(ds, "destroy", tx, "");
727 
728 	rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
729 	    DS_IS_DEFER_DESTROY(ds->ds_prev) &&
730 	    dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
731 	    ds->ds_prev->ds_userrefs == 0);
732 
733 	/* Remove our reservation. */
734 	if (ds->ds_reserved != 0) {
735 		dsl_dataset_set_refreservation_sync_impl(ds,
736 		    (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
737 		    0, tx);
738 		ASSERT0(ds->ds_reserved);
739 	}
740 
741 	obj = ds->ds_object;
742 
743 	for (spa_feature_t f = 0; f < SPA_FEATURES; f++) {
744 		if (ds->ds_feature_inuse[f]) {
745 			dsl_dataset_deactivate_feature(obj, f, tx);
746 			ds->ds_feature_inuse[f] = B_FALSE;
747 		}
748 	}
749 
750 	dsl_scan_ds_destroyed(ds, tx);
751 
752 	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
753 		/* This is a clone */
754 		ASSERT(ds->ds_prev != NULL);
755 		ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj, !=,
756 		    obj);
757 		ASSERT0(dsl_dataset_phys(ds)->ds_next_snap_obj);
758 
759 		dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
760 		if (dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj != 0) {
761 			dsl_dataset_remove_from_next_clones(ds->ds_prev,
762 			    obj, tx);
763 		}
764 
765 		ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_num_children, >, 1);
766 		dsl_dataset_phys(ds->ds_prev)->ds_num_children--;
767 	}
768 
769 	/*
770 	 * Destroy the deadlist.  Unless it's a clone, the
771 	 * deadlist should be empty.  (If it's a clone, it's
772 	 * safe to ignore the deadlist contents.)
773 	 */
774 	dsl_deadlist_close(&ds->ds_deadlist);
775 	dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
776 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
777 	dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
778 
779 	objset_t *os;
780 	VERIFY0(dmu_objset_from_ds(ds, &os));
781 
782 	if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
783 		old_synchronous_dataset_destroy(ds, tx);
784 	} else {
785 		/*
786 		 * Move the bptree into the pool's list of trees to
787 		 * clean up and update space accounting information.
788 		 */
789 		uint64_t used, comp, uncomp;
790 
791 		zil_destroy_sync(dmu_objset_zil(os), tx);
792 
793 		if (!spa_feature_is_active(dp->dp_spa,
794 		    SPA_FEATURE_ASYNC_DESTROY)) {
795 			dsl_scan_t *scn = dp->dp_scan;
796 			spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
797 			    tx);
798 			dp->dp_bptree_obj = bptree_alloc(mos, tx);
799 			VERIFY0(zap_add(mos,
800 			    DMU_POOL_DIRECTORY_OBJECT,
801 			    DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
802 			    &dp->dp_bptree_obj, tx));
803 			ASSERT(!scn->scn_async_destroying);
804 			scn->scn_async_destroying = B_TRUE;
805 		}
806 
807 		used = dsl_dir_phys(ds->ds_dir)->dd_used_bytes;
808 		comp = dsl_dir_phys(ds->ds_dir)->dd_compressed_bytes;
809 		uncomp = dsl_dir_phys(ds->ds_dir)->dd_uncompressed_bytes;
810 
811 		ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
812 		    dsl_dataset_phys(ds)->ds_unique_bytes == used);
813 
814 		bptree_add(mos, dp->dp_bptree_obj,
815 		    &dsl_dataset_phys(ds)->ds_bp,
816 		    dsl_dataset_phys(ds)->ds_prev_snap_txg,
817 		    used, comp, uncomp, tx);
818 		dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
819 		    -used, -comp, -uncomp, tx);
820 		dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
821 		    used, comp, uncomp, tx);
822 	}
823 
824 	if (ds->ds_prev != NULL) {
825 		if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
826 			VERIFY0(zap_remove_int(mos,
827 			    dsl_dir_phys(ds->ds_prev->ds_dir)->dd_clones,
828 			    ds->ds_object, tx));
829 		}
830 		prevobj = ds->ds_prev->ds_object;
831 		dsl_dataset_rele(ds->ds_prev, ds);
832 		ds->ds_prev = NULL;
833 	}
834 
835 	/*
836 	 * This must be done after the dsl_traverse(), because it will
837 	 * re-open the objset.
838 	 */
839 	if (ds->ds_objset) {
840 		dmu_objset_evict(ds->ds_objset);
841 		ds->ds_objset = NULL;
842 	}
843 
844 	/* Erase the link in the dir */
845 	dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
846 	dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj = 0;
847 	ddobj = ds->ds_dir->dd_object;
848 	ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0);
849 	VERIFY0(zap_destroy(mos,
850 	    dsl_dataset_phys(ds)->ds_snapnames_zapobj, tx));
851 
852 	if (ds->ds_bookmarks != 0) {
853 		VERIFY0(zap_destroy(mos, ds->ds_bookmarks, tx));
854 		spa_feature_decr(dp->dp_spa, SPA_FEATURE_BOOKMARKS, tx);
855 	}
856 
857 	spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
858 
859 	ASSERT0(dsl_dataset_phys(ds)->ds_next_clones_obj);
860 	ASSERT0(dsl_dataset_phys(ds)->ds_props_obj);
861 	ASSERT0(dsl_dataset_phys(ds)->ds_userrefs_obj);
862 	dsl_dir_rele(ds->ds_dir, ds);
863 	ds->ds_dir = NULL;
864 	dmu_object_free_zapified(mos, obj, tx);
865 
866 	dsl_dir_destroy_sync(ddobj, tx);
867 
868 	if (rmorigin) {
869 		dsl_dataset_t *prev;
870 		VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
871 		dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
872 		dsl_dataset_rele(prev, FTAG);
873 	}
874 }
875 
876 static void
dsl_destroy_head_sync(void * arg,dmu_tx_t * tx)877 dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
878 {
879 	dsl_destroy_head_arg_t *ddha = arg;
880 	dsl_pool_t *dp = dmu_tx_pool(tx);
881 	dsl_dataset_t *ds;
882 
883 	VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
884 	dsl_destroy_head_sync_impl(ds, tx);
885 	dsl_dataset_rele(ds, FTAG);
886 }
887 
888 static void
dsl_destroy_head_begin_sync(void * arg,dmu_tx_t * tx)889 dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
890 {
891 	dsl_destroy_head_arg_t *ddha = arg;
892 	dsl_pool_t *dp = dmu_tx_pool(tx);
893 	dsl_dataset_t *ds;
894 
895 	VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
896 
897 	/* Mark it as inconsistent on-disk, in case we crash */
898 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
899 	dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
900 
901 	spa_history_log_internal_ds(ds, "destroy begin", tx, "");
902 	dsl_dataset_rele(ds, FTAG);
903 }
904 
905 int
dsl_destroy_head(const char * name)906 dsl_destroy_head(const char *name)
907 {
908 	dsl_destroy_head_arg_t ddha;
909 	int error;
910 	spa_t *spa;
911 	boolean_t isenabled;
912 
913 #ifdef _KERNEL
914 	zfs_destroy_unmount_origin(name);
915 #endif
916 
917 	error = spa_open(name, &spa, FTAG);
918 	if (error != 0)
919 		return (error);
920 	isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
921 	spa_close(spa, FTAG);
922 
923 	ddha.ddha_name = name;
924 
925 	if (!isenabled) {
926 		objset_t *os;
927 
928 		error = dsl_sync_task(name, dsl_destroy_head_check,
929 		    dsl_destroy_head_begin_sync, &ddha,
930 		    0, ZFS_SPACE_CHECK_NONE);
931 		if (error != 0)
932 			return (error);
933 
934 		/*
935 		 * Head deletion is processed in one txg on old pools;
936 		 * remove the objects from open context so that the txg sync
937 		 * is not too long.
938 		 */
939 		error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, FTAG, &os);
940 		if (error == 0) {
941 			uint64_t prev_snap_txg =
942 			    dsl_dataset_phys(dmu_objset_ds(os))->
943 			    ds_prev_snap_txg;
944 			for (uint64_t obj = 0; error == 0;
945 			    error = dmu_object_next(os, &obj, FALSE,
946 			    prev_snap_txg))
947 				(void) dmu_free_long_object(os, obj);
948 			/* sync out all frees */
949 			txg_wait_synced(dmu_objset_pool(os), 0);
950 			dmu_objset_disown(os, FTAG);
951 		}
952 	}
953 
954 	return (dsl_sync_task(name, dsl_destroy_head_check,
955 	    dsl_destroy_head_sync, &ddha, 0, ZFS_SPACE_CHECK_NONE));
956 }
957 
958 /*
959  * Note, this function is used as the callback for dmu_objset_find().  We
960  * always return 0 so that we will continue to find and process
961  * inconsistent datasets, even if we encounter an error trying to
962  * process one of them.
963  */
964 /* ARGSUSED */
965 int
dsl_destroy_inconsistent(const char * dsname,void * arg)966 dsl_destroy_inconsistent(const char *dsname, void *arg)
967 {
968 	objset_t *os;
969 
970 	if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
971 		boolean_t need_destroy = DS_IS_INCONSISTENT(dmu_objset_ds(os));
972 
973 		/*
974 		 * If the dataset is inconsistent because a resumable receive
975 		 * has failed, then do not destroy it.
976 		 */
977 		if (dsl_dataset_has_resume_receive_state(dmu_objset_ds(os)))
978 			need_destroy = B_FALSE;
979 
980 		dmu_objset_rele(os, FTAG);
981 		if (need_destroy)
982 			(void) dsl_destroy_head(dsname);
983 	}
984 	return (0);
985 }
986