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