dsl_destroy.c revision 288571
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, 2014 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
44typedef 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
51int
52dsl_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
87static int
88dsl_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
134struct 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
142static int
143process_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
167static void
168process_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
205static void
206dsl_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
237void
238dsl_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	if (ds->ds_large_blocks) {
271		ASSERT0(zap_contains(mos, obj, DS_FIELD_LARGE_BLOCKS));
272		spa_feature_decr(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS, tx);
273	}
274	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
275		ASSERT3P(ds->ds_prev, ==, NULL);
276		VERIFY0(dsl_dataset_hold_obj(dp,
277		    dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &ds_prev));
278		after_branch_point =
279		    (dsl_dataset_phys(ds_prev)->ds_next_snap_obj != obj);
280
281		dmu_buf_will_dirty(ds_prev->ds_dbuf, tx);
282		if (after_branch_point &&
283		    dsl_dataset_phys(ds_prev)->ds_next_clones_obj != 0) {
284			dsl_dataset_remove_from_next_clones(ds_prev, obj, tx);
285			if (dsl_dataset_phys(ds)->ds_next_snap_obj != 0) {
286				VERIFY0(zap_add_int(mos,
287				    dsl_dataset_phys(ds_prev)->
288				    ds_next_clones_obj,
289				    dsl_dataset_phys(ds)->ds_next_snap_obj,
290				    tx));
291			}
292		}
293		if (!after_branch_point) {
294			dsl_dataset_phys(ds_prev)->ds_next_snap_obj =
295			    dsl_dataset_phys(ds)->ds_next_snap_obj;
296		}
297	}
298
299	dsl_dataset_t *ds_next;
300	uint64_t old_unique;
301	uint64_t used = 0, comp = 0, uncomp = 0;
302
303	VERIFY0(dsl_dataset_hold_obj(dp,
304	    dsl_dataset_phys(ds)->ds_next_snap_obj, FTAG, &ds_next));
305	ASSERT3U(dsl_dataset_phys(ds_next)->ds_prev_snap_obj, ==, obj);
306
307	old_unique = dsl_dataset_phys(ds_next)->ds_unique_bytes;
308
309	dmu_buf_will_dirty(ds_next->ds_dbuf, tx);
310	dsl_dataset_phys(ds_next)->ds_prev_snap_obj =
311	    dsl_dataset_phys(ds)->ds_prev_snap_obj;
312	dsl_dataset_phys(ds_next)->ds_prev_snap_txg =
313	    dsl_dataset_phys(ds)->ds_prev_snap_txg;
314	ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_txg, ==,
315	    ds_prev ? dsl_dataset_phys(ds_prev)->ds_creation_txg : 0);
316
317	if (ds_next->ds_deadlist.dl_oldfmt) {
318		process_old_deadlist(ds, ds_prev, ds_next,
319		    after_branch_point, tx);
320	} else {
321		/* Adjust prev's unique space. */
322		if (ds_prev && !after_branch_point) {
323			dsl_deadlist_space_range(&ds_next->ds_deadlist,
324			    dsl_dataset_phys(ds_prev)->ds_prev_snap_txg,
325			    dsl_dataset_phys(ds)->ds_prev_snap_txg,
326			    &used, &comp, &uncomp);
327			dsl_dataset_phys(ds_prev)->ds_unique_bytes += used;
328		}
329
330		/* Adjust snapused. */
331		dsl_deadlist_space_range(&ds_next->ds_deadlist,
332		    dsl_dataset_phys(ds)->ds_prev_snap_txg, UINT64_MAX,
333		    &used, &comp, &uncomp);
334		dsl_dir_diduse_space(ds->ds_dir, DD_USED_SNAP,
335		    -used, -comp, -uncomp, tx);
336
337		/* Move blocks to be freed to pool's free list. */
338		dsl_deadlist_move_bpobj(&ds_next->ds_deadlist,
339		    &dp->dp_free_bpobj, dsl_dataset_phys(ds)->ds_prev_snap_txg,
340		    tx);
341		dsl_dir_diduse_space(tx->tx_pool->dp_free_dir,
342		    DD_USED_HEAD, used, comp, uncomp, tx);
343
344		/* Merge our deadlist into next's and free it. */
345		dsl_deadlist_merge(&ds_next->ds_deadlist,
346		    dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
347	}
348	dsl_deadlist_close(&ds->ds_deadlist);
349	dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
350	dmu_buf_will_dirty(ds->ds_dbuf, tx);
351	dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
352
353	/* Collapse range in clone heads */
354	dsl_dataset_remove_clones_key(ds,
355	    dsl_dataset_phys(ds)->ds_creation_txg, tx);
356
357	if (ds_next->ds_is_snapshot) {
358		dsl_dataset_t *ds_nextnext;
359
360		/*
361		 * Update next's unique to include blocks which
362		 * were previously shared by only this snapshot
363		 * and it.  Those blocks will be born after the
364		 * prev snap and before this snap, and will have
365		 * died after the next snap and before the one
366		 * after that (ie. be on the snap after next's
367		 * deadlist).
368		 */
369		VERIFY0(dsl_dataset_hold_obj(dp,
370		    dsl_dataset_phys(ds_next)->ds_next_snap_obj,
371		    FTAG, &ds_nextnext));
372		dsl_deadlist_space_range(&ds_nextnext->ds_deadlist,
373		    dsl_dataset_phys(ds)->ds_prev_snap_txg,
374		    dsl_dataset_phys(ds)->ds_creation_txg,
375		    &used, &comp, &uncomp);
376		dsl_dataset_phys(ds_next)->ds_unique_bytes += used;
377		dsl_dataset_rele(ds_nextnext, FTAG);
378		ASSERT3P(ds_next->ds_prev, ==, NULL);
379
380		/* Collapse range in this head. */
381		dsl_dataset_t *hds;
382		VERIFY0(dsl_dataset_hold_obj(dp,
383		    dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &hds));
384		dsl_deadlist_remove_key(&hds->ds_deadlist,
385		    dsl_dataset_phys(ds)->ds_creation_txg, tx);
386		dsl_dataset_rele(hds, FTAG);
387
388	} else {
389		ASSERT3P(ds_next->ds_prev, ==, ds);
390		dsl_dataset_rele(ds_next->ds_prev, ds_next);
391		ds_next->ds_prev = NULL;
392		if (ds_prev) {
393			VERIFY0(dsl_dataset_hold_obj(dp,
394			    dsl_dataset_phys(ds)->ds_prev_snap_obj,
395			    ds_next, &ds_next->ds_prev));
396		}
397
398		dsl_dataset_recalc_head_uniq(ds_next);
399
400		/*
401		 * Reduce the amount of our unconsumed refreservation
402		 * being charged to our parent by the amount of
403		 * new unique data we have gained.
404		 */
405		if (old_unique < ds_next->ds_reserved) {
406			int64_t mrsdelta;
407			uint64_t new_unique =
408			    dsl_dataset_phys(ds_next)->ds_unique_bytes;
409
410			ASSERT(old_unique <= new_unique);
411			mrsdelta = MIN(new_unique - old_unique,
412			    ds_next->ds_reserved - old_unique);
413			dsl_dir_diduse_space(ds->ds_dir,
414			    DD_USED_REFRSRV, -mrsdelta, 0, 0, tx);
415		}
416	}
417	dsl_dataset_rele(ds_next, FTAG);
418
419	/*
420	 * This must be done after the dsl_traverse(), because it will
421	 * re-open the objset.
422	 */
423	if (ds->ds_objset) {
424		dmu_objset_evict(ds->ds_objset);
425		ds->ds_objset = NULL;
426	}
427
428	/* remove from snapshot namespace */
429	dsl_dataset_t *ds_head;
430	ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj == 0);
431	VERIFY0(dsl_dataset_hold_obj(dp,
432	    dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj, FTAG, &ds_head));
433	VERIFY0(dsl_dataset_get_snapname(ds));
434#ifdef ZFS_DEBUG
435	{
436		uint64_t val;
437
438		err = dsl_dataset_snap_lookup(ds_head,
439		    ds->ds_snapname, &val);
440		ASSERT0(err);
441		ASSERT3U(val, ==, obj);
442	}
443#endif
444	VERIFY0(dsl_dataset_snap_remove(ds_head, ds->ds_snapname, tx, B_TRUE));
445	dsl_dataset_rele(ds_head, FTAG);
446
447	if (ds_prev != NULL)
448		dsl_dataset_rele(ds_prev, FTAG);
449
450	spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
451
452	if (dsl_dataset_phys(ds)->ds_next_clones_obj != 0) {
453		uint64_t count;
454		ASSERT0(zap_count(mos,
455		    dsl_dataset_phys(ds)->ds_next_clones_obj, &count) &&
456		    count == 0);
457		VERIFY0(dmu_object_free(mos,
458		    dsl_dataset_phys(ds)->ds_next_clones_obj, tx));
459	}
460	if (dsl_dataset_phys(ds)->ds_props_obj != 0)
461		VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_props_obj,
462		    tx));
463	if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0)
464		VERIFY0(zap_destroy(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
465		    tx));
466	dsl_dir_rele(ds->ds_dir, ds);
467	ds->ds_dir = NULL;
468	dmu_object_free_zapified(mos, obj, tx);
469}
470
471static void
472dsl_destroy_snapshot_sync(void *arg, dmu_tx_t *tx)
473{
474	dmu_snapshots_destroy_arg_t *dsda = arg;
475	dsl_pool_t *dp = dmu_tx_pool(tx);
476	nvpair_t *pair;
477
478	for (pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, NULL);
479	    pair != NULL;
480	    pair = nvlist_next_nvpair(dsda->dsda_successful_snaps, pair)) {
481		dsl_dataset_t *ds;
482
483		VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
484
485		dsl_destroy_snapshot_sync_impl(ds, dsda->dsda_defer, tx);
486		dsl_dataset_rele(ds, FTAG);
487	}
488}
489
490/*
491 * The semantics of this function are described in the comment above
492 * lzc_destroy_snaps().  To summarize:
493 *
494 * The snapshots must all be in the same pool.
495 *
496 * Snapshots that don't exist will be silently ignored (considered to be
497 * "already deleted").
498 *
499 * On success, all snaps will be destroyed and this will return 0.
500 * On failure, no snaps will be destroyed, the errlist will be filled in,
501 * and this will return an errno.
502 */
503int
504dsl_destroy_snapshots_nvl(nvlist_t *snaps, boolean_t defer,
505    nvlist_t *errlist)
506{
507	dmu_snapshots_destroy_arg_t dsda;
508	int error;
509	nvpair_t *pair;
510
511	pair = nvlist_next_nvpair(snaps, NULL);
512	if (pair == NULL)
513		return (0);
514
515	dsda.dsda_snaps = snaps;
516	dsda.dsda_successful_snaps = fnvlist_alloc();
517	dsda.dsda_defer = defer;
518	dsda.dsda_errlist = errlist;
519
520	error = dsl_sync_task(nvpair_name(pair),
521	    dsl_destroy_snapshot_check, dsl_destroy_snapshot_sync,
522	    &dsda, 0, ZFS_SPACE_CHECK_NONE);
523	fnvlist_free(dsda.dsda_successful_snaps);
524
525	return (error);
526}
527
528int
529dsl_destroy_snapshot(const char *name, boolean_t defer)
530{
531	int error;
532	nvlist_t *nvl = fnvlist_alloc();
533	nvlist_t *errlist = fnvlist_alloc();
534
535	fnvlist_add_boolean(nvl, name);
536	error = dsl_destroy_snapshots_nvl(nvl, defer, errlist);
537	fnvlist_free(errlist);
538	fnvlist_free(nvl);
539	return (error);
540}
541
542struct killarg {
543	dsl_dataset_t *ds;
544	dmu_tx_t *tx;
545};
546
547/* ARGSUSED */
548static int
549kill_blkptr(spa_t *spa, zilog_t *zilog, const blkptr_t *bp,
550    const zbookmark_phys_t *zb, const dnode_phys_t *dnp, void *arg)
551{
552	struct killarg *ka = arg;
553	dmu_tx_t *tx = ka->tx;
554
555	if (bp == NULL || BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp))
556		return (0);
557
558	if (zb->zb_level == ZB_ZIL_LEVEL) {
559		ASSERT(zilog != NULL);
560		/*
561		 * It's a block in the intent log.  It has no
562		 * accounting, so just free it.
563		 */
564		dsl_free(ka->tx->tx_pool, ka->tx->tx_txg, bp);
565	} else {
566		ASSERT(zilog == NULL);
567		ASSERT3U(bp->blk_birth, >,
568		    dsl_dataset_phys(ka->ds)->ds_prev_snap_txg);
569		(void) dsl_dataset_block_kill(ka->ds, bp, tx, B_FALSE);
570	}
571
572	return (0);
573}
574
575static void
576old_synchronous_dataset_destroy(dsl_dataset_t *ds, dmu_tx_t *tx)
577{
578	struct killarg ka;
579
580	/*
581	 * Free everything that we point to (that's born after
582	 * the previous snapshot, if we are a clone)
583	 *
584	 * NB: this should be very quick, because we already
585	 * freed all the objects in open context.
586	 */
587	ka.ds = ds;
588	ka.tx = tx;
589	VERIFY0(traverse_dataset(ds,
590	    dsl_dataset_phys(ds)->ds_prev_snap_txg, TRAVERSE_POST,
591	    kill_blkptr, &ka));
592	ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
593	    dsl_dataset_phys(ds)->ds_unique_bytes == 0);
594}
595
596typedef struct dsl_destroy_head_arg {
597	const char *ddha_name;
598} dsl_destroy_head_arg_t;
599
600int
601dsl_destroy_head_check_impl(dsl_dataset_t *ds, int expected_holds)
602{
603	int error;
604	uint64_t count;
605	objset_t *mos;
606
607	ASSERT(!ds->ds_is_snapshot);
608	if (ds->ds_is_snapshot)
609		return (SET_ERROR(EINVAL));
610
611	if (refcount_count(&ds->ds_longholds) != expected_holds)
612		return (SET_ERROR(EBUSY));
613
614	mos = ds->ds_dir->dd_pool->dp_meta_objset;
615
616	/*
617	 * Can't delete a head dataset if there are snapshots of it.
618	 * (Except if the only snapshots are from the branch we cloned
619	 * from.)
620	 */
621	if (ds->ds_prev != NULL &&
622	    dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj == ds->ds_object)
623		return (SET_ERROR(EBUSY));
624
625	/*
626	 * Can't delete if there are children of this fs.
627	 */
628	error = zap_count(mos,
629	    dsl_dir_phys(ds->ds_dir)->dd_child_dir_zapobj, &count);
630	if (error != 0)
631		return (error);
632	if (count != 0)
633		return (SET_ERROR(EEXIST));
634
635	if (dsl_dir_is_clone(ds->ds_dir) && DS_IS_DEFER_DESTROY(ds->ds_prev) &&
636	    dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
637	    ds->ds_prev->ds_userrefs == 0) {
638		/* We need to remove the origin snapshot as well. */
639		if (!refcount_is_zero(&ds->ds_prev->ds_longholds))
640			return (SET_ERROR(EBUSY));
641	}
642	return (0);
643}
644
645static int
646dsl_destroy_head_check(void *arg, dmu_tx_t *tx)
647{
648	dsl_destroy_head_arg_t *ddha = arg;
649	dsl_pool_t *dp = dmu_tx_pool(tx);
650	dsl_dataset_t *ds;
651	int error;
652
653	error = dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds);
654	if (error != 0)
655		return (error);
656
657	error = dsl_destroy_head_check_impl(ds, 0);
658	dsl_dataset_rele(ds, FTAG);
659	return (error);
660}
661
662static void
663dsl_dir_destroy_sync(uint64_t ddobj, dmu_tx_t *tx)
664{
665	dsl_dir_t *dd;
666	dsl_pool_t *dp = dmu_tx_pool(tx);
667	objset_t *mos = dp->dp_meta_objset;
668	dd_used_t t;
669
670	ASSERT(RRW_WRITE_HELD(&dmu_tx_pool(tx)->dp_config_rwlock));
671
672	VERIFY0(dsl_dir_hold_obj(dp, ddobj, NULL, FTAG, &dd));
673
674	ASSERT0(dsl_dir_phys(dd)->dd_head_dataset_obj);
675
676	/*
677	 * Decrement the filesystem count for all parent filesystems.
678	 *
679	 * When we receive an incremental stream into a filesystem that already
680	 * exists, a temporary clone is created.  We never count this temporary
681	 * clone, whose name begins with a '%'.
682	 */
683	if (dd->dd_myname[0] != '%' && dd->dd_parent != NULL)
684		dsl_fs_ss_count_adjust(dd->dd_parent, -1,
685		    DD_FIELD_FILESYSTEM_COUNT, tx);
686
687	/*
688	 * Remove our reservation. The impl() routine avoids setting the
689	 * actual property, which would require the (already destroyed) ds.
690	 */
691	dsl_dir_set_reservation_sync_impl(dd, 0, tx);
692
693	ASSERT0(dsl_dir_phys(dd)->dd_used_bytes);
694	ASSERT0(dsl_dir_phys(dd)->dd_reserved);
695	for (t = 0; t < DD_USED_NUM; t++)
696		ASSERT0(dsl_dir_phys(dd)->dd_used_breakdown[t]);
697
698	VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_child_dir_zapobj, tx));
699	VERIFY0(zap_destroy(mos, dsl_dir_phys(dd)->dd_props_zapobj, tx));
700	VERIFY0(dsl_deleg_destroy(mos, dsl_dir_phys(dd)->dd_deleg_zapobj, tx));
701	VERIFY0(zap_remove(mos,
702	    dsl_dir_phys(dd->dd_parent)->dd_child_dir_zapobj,
703	    dd->dd_myname, tx));
704
705	dsl_dir_rele(dd, FTAG);
706	dmu_object_free_zapified(mos, ddobj, tx);
707}
708
709void
710dsl_destroy_head_sync_impl(dsl_dataset_t *ds, dmu_tx_t *tx)
711{
712	dsl_pool_t *dp = dmu_tx_pool(tx);
713	objset_t *mos = dp->dp_meta_objset;
714	uint64_t obj, ddobj, prevobj = 0;
715	boolean_t rmorigin;
716
717	ASSERT3U(dsl_dataset_phys(ds)->ds_num_children, <=, 1);
718	ASSERT(ds->ds_prev == NULL ||
719	    dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj != ds->ds_object);
720	ASSERT3U(dsl_dataset_phys(ds)->ds_bp.blk_birth, <=, tx->tx_txg);
721	ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
722
723	/* We need to log before removing it from the namespace. */
724	spa_history_log_internal_ds(ds, "destroy", tx, "");
725
726	rmorigin = (dsl_dir_is_clone(ds->ds_dir) &&
727	    DS_IS_DEFER_DESTROY(ds->ds_prev) &&
728	    dsl_dataset_phys(ds->ds_prev)->ds_num_children == 2 &&
729	    ds->ds_prev->ds_userrefs == 0);
730
731	/* Remove our reservation. */
732	if (ds->ds_reserved != 0) {
733		dsl_dataset_set_refreservation_sync_impl(ds,
734		    (ZPROP_SRC_NONE | ZPROP_SRC_LOCAL | ZPROP_SRC_RECEIVED),
735		    0, tx);
736		ASSERT0(ds->ds_reserved);
737	}
738
739	if (ds->ds_large_blocks)
740		spa_feature_decr(dp->dp_spa, SPA_FEATURE_LARGE_BLOCKS, tx);
741
742	dsl_scan_ds_destroyed(ds, tx);
743
744	obj = ds->ds_object;
745
746	if (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
747		/* This is a clone */
748		ASSERT(ds->ds_prev != NULL);
749		ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_next_snap_obj, !=,
750		    obj);
751		ASSERT0(dsl_dataset_phys(ds)->ds_next_snap_obj);
752
753		dmu_buf_will_dirty(ds->ds_prev->ds_dbuf, tx);
754		if (dsl_dataset_phys(ds->ds_prev)->ds_next_clones_obj != 0) {
755			dsl_dataset_remove_from_next_clones(ds->ds_prev,
756			    obj, tx);
757		}
758
759		ASSERT3U(dsl_dataset_phys(ds->ds_prev)->ds_num_children, >, 1);
760		dsl_dataset_phys(ds->ds_prev)->ds_num_children--;
761	}
762
763	/*
764	 * Destroy the deadlist.  Unless it's a clone, the
765	 * deadlist should be empty.  (If it's a clone, it's
766	 * safe to ignore the deadlist contents.)
767	 */
768	dsl_deadlist_close(&ds->ds_deadlist);
769	dsl_deadlist_free(mos, dsl_dataset_phys(ds)->ds_deadlist_obj, tx);
770	dmu_buf_will_dirty(ds->ds_dbuf, tx);
771	dsl_dataset_phys(ds)->ds_deadlist_obj = 0;
772
773	objset_t *os;
774	VERIFY0(dmu_objset_from_ds(ds, &os));
775
776	if (!spa_feature_is_enabled(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
777		old_synchronous_dataset_destroy(ds, tx);
778	} else {
779		/*
780		 * Move the bptree into the pool's list of trees to
781		 * clean up and update space accounting information.
782		 */
783		uint64_t used, comp, uncomp;
784
785		zil_destroy_sync(dmu_objset_zil(os), tx);
786
787		if (!spa_feature_is_active(dp->dp_spa,
788		    SPA_FEATURE_ASYNC_DESTROY)) {
789			dsl_scan_t *scn = dp->dp_scan;
790			spa_feature_incr(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY,
791			    tx);
792			dp->dp_bptree_obj = bptree_alloc(mos, tx);
793			VERIFY0(zap_add(mos,
794			    DMU_POOL_DIRECTORY_OBJECT,
795			    DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
796			    &dp->dp_bptree_obj, tx));
797			ASSERT(!scn->scn_async_destroying);
798			scn->scn_async_destroying = B_TRUE;
799		}
800
801		used = dsl_dir_phys(ds->ds_dir)->dd_used_bytes;
802		comp = dsl_dir_phys(ds->ds_dir)->dd_compressed_bytes;
803		uncomp = dsl_dir_phys(ds->ds_dir)->dd_uncompressed_bytes;
804
805		ASSERT(!DS_UNIQUE_IS_ACCURATE(ds) ||
806		    dsl_dataset_phys(ds)->ds_unique_bytes == used);
807
808		bptree_add(mos, dp->dp_bptree_obj,
809		    &dsl_dataset_phys(ds)->ds_bp,
810		    dsl_dataset_phys(ds)->ds_prev_snap_txg,
811		    used, comp, uncomp, tx);
812		dsl_dir_diduse_space(ds->ds_dir, DD_USED_HEAD,
813		    -used, -comp, -uncomp, tx);
814		dsl_dir_diduse_space(dp->dp_free_dir, DD_USED_HEAD,
815		    used, comp, uncomp, tx);
816	}
817
818	if (ds->ds_prev != NULL) {
819		if (spa_version(dp->dp_spa) >= SPA_VERSION_DIR_CLONES) {
820			VERIFY0(zap_remove_int(mos,
821			    dsl_dir_phys(ds->ds_prev->ds_dir)->dd_clones,
822			    ds->ds_object, tx));
823		}
824		prevobj = ds->ds_prev->ds_object;
825		dsl_dataset_rele(ds->ds_prev, ds);
826		ds->ds_prev = NULL;
827	}
828
829	/*
830	 * This must be done after the dsl_traverse(), because it will
831	 * re-open the objset.
832	 */
833	if (ds->ds_objset) {
834		dmu_objset_evict(ds->ds_objset);
835		ds->ds_objset = NULL;
836	}
837
838	/* Erase the link in the dir */
839	dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
840	dsl_dir_phys(ds->ds_dir)->dd_head_dataset_obj = 0;
841	ddobj = ds->ds_dir->dd_object;
842	ASSERT(dsl_dataset_phys(ds)->ds_snapnames_zapobj != 0);
843	VERIFY0(zap_destroy(mos,
844	    dsl_dataset_phys(ds)->ds_snapnames_zapobj, tx));
845
846	if (ds->ds_bookmarks != 0) {
847		VERIFY0(zap_destroy(mos, ds->ds_bookmarks, tx));
848		spa_feature_decr(dp->dp_spa, SPA_FEATURE_BOOKMARKS, tx);
849	}
850
851	spa_prop_clear_bootfs(dp->dp_spa, ds->ds_object, tx);
852
853	ASSERT0(dsl_dataset_phys(ds)->ds_next_clones_obj);
854	ASSERT0(dsl_dataset_phys(ds)->ds_props_obj);
855	ASSERT0(dsl_dataset_phys(ds)->ds_userrefs_obj);
856	dsl_dir_rele(ds->ds_dir, ds);
857	ds->ds_dir = NULL;
858	dmu_object_free_zapified(mos, obj, tx);
859
860	dsl_dir_destroy_sync(ddobj, tx);
861
862	if (rmorigin) {
863		dsl_dataset_t *prev;
864		VERIFY0(dsl_dataset_hold_obj(dp, prevobj, FTAG, &prev));
865		dsl_destroy_snapshot_sync_impl(prev, B_FALSE, tx);
866		dsl_dataset_rele(prev, FTAG);
867	}
868}
869
870static void
871dsl_destroy_head_sync(void *arg, dmu_tx_t *tx)
872{
873	dsl_destroy_head_arg_t *ddha = arg;
874	dsl_pool_t *dp = dmu_tx_pool(tx);
875	dsl_dataset_t *ds;
876
877	VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
878	dsl_destroy_head_sync_impl(ds, tx);
879	dsl_dataset_rele(ds, FTAG);
880}
881
882static void
883dsl_destroy_head_begin_sync(void *arg, dmu_tx_t *tx)
884{
885	dsl_destroy_head_arg_t *ddha = arg;
886	dsl_pool_t *dp = dmu_tx_pool(tx);
887	dsl_dataset_t *ds;
888
889	VERIFY0(dsl_dataset_hold(dp, ddha->ddha_name, FTAG, &ds));
890
891	/* Mark it as inconsistent on-disk, in case we crash */
892	dmu_buf_will_dirty(ds->ds_dbuf, tx);
893	dsl_dataset_phys(ds)->ds_flags |= DS_FLAG_INCONSISTENT;
894
895	spa_history_log_internal_ds(ds, "destroy begin", tx, "");
896	dsl_dataset_rele(ds, FTAG);
897}
898
899int
900dsl_destroy_head(const char *name)
901{
902	dsl_destroy_head_arg_t ddha;
903	int error;
904	spa_t *spa;
905	boolean_t isenabled;
906
907#ifdef _KERNEL
908	zfs_destroy_unmount_origin(name);
909#endif
910
911	error = spa_open(name, &spa, FTAG);
912	if (error != 0)
913		return (error);
914	isenabled = spa_feature_is_enabled(spa, SPA_FEATURE_ASYNC_DESTROY);
915	spa_close(spa, FTAG);
916
917	ddha.ddha_name = name;
918
919	if (!isenabled) {
920		objset_t *os;
921
922		error = dsl_sync_task(name, dsl_destroy_head_check,
923		    dsl_destroy_head_begin_sync, &ddha,
924		    0, ZFS_SPACE_CHECK_NONE);
925		if (error != 0)
926			return (error);
927
928		/*
929		 * Head deletion is processed in one txg on old pools;
930		 * remove the objects from open context so that the txg sync
931		 * is not too long.
932		 */
933		error = dmu_objset_own(name, DMU_OST_ANY, B_FALSE, FTAG, &os);
934		if (error == 0) {
935			uint64_t prev_snap_txg =
936			    dsl_dataset_phys(dmu_objset_ds(os))->
937			    ds_prev_snap_txg;
938			for (uint64_t obj = 0; error == 0;
939			    error = dmu_object_next(os, &obj, FALSE,
940			    prev_snap_txg))
941				(void) dmu_free_long_object(os, obj);
942			/* sync out all frees */
943			txg_wait_synced(dmu_objset_pool(os), 0);
944			dmu_objset_disown(os, FTAG);
945		}
946	}
947
948	return (dsl_sync_task(name, dsl_destroy_head_check,
949	    dsl_destroy_head_sync, &ddha, 0, ZFS_SPACE_CHECK_NONE));
950}
951
952/*
953 * Note, this function is used as the callback for dmu_objset_find().  We
954 * always return 0 so that we will continue to find and process
955 * inconsistent datasets, even if we encounter an error trying to
956 * process one of them.
957 */
958/* ARGSUSED */
959int
960dsl_destroy_inconsistent(const char *dsname, void *arg)
961{
962	objset_t *os;
963
964	if (dmu_objset_hold(dsname, FTAG, &os) == 0) {
965		boolean_t inconsistent = DS_IS_INCONSISTENT(dmu_objset_ds(os));
966		dmu_objset_rele(os, FTAG);
967		if (inconsistent)
968			(void) dsl_destroy_head(dsname);
969	}
970	return (0);
971}
972