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.
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.
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]
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.
27 #include <sys/zfs_context.h>
28 #include <sys/dsl_userhold.h>
29 #include <sys/dsl_dataset.h>
30 #include <sys/dsl_destroy.h>
31 #include <sys/dsl_synctask.h>
32 #include <sys/dmu_tx.h>
33 #include <sys/zfs_onexit.h>
34 #include <sys/dsl_pool.h>
35 #include <sys/dsl_dir.h>
36 #include <sys/zfs_ioctl.h>
39 typedef struct dsl_dataset_user_hold_arg {
40 nvlist_t *dduha_holds;
41 nvlist_t *dduha_chkholds;
42 nvlist_t *dduha_errlist;
44 } dsl_dataset_user_hold_arg_t;
47 * If you add new checks here, you may need to add additional checks to the
48 * "temporary" case in snapshot_check() in dmu_objset.c.
51 dsl_dataset_user_hold_check_one(dsl_dataset_t *ds, const char *htag,
52 boolean_t temphold, dmu_tx_t *tx)
54 dsl_pool_t *dp = dmu_tx_pool(tx);
55 objset_t *mos = dp->dp_meta_objset;
58 ASSERT(dsl_pool_config_held(dp));
60 if (strlen(htag) > MAXNAMELEN)
61 return (SET_ERROR(E2BIG));
62 /* Tempholds have a more restricted length */
63 if (temphold && strlen(htag) + MAX_TAG_PREFIX_LEN >= MAXNAMELEN)
64 return (SET_ERROR(E2BIG));
66 /* tags must be unique (if ds already exists) */
67 if (ds != NULL && dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
70 error = zap_lookup(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
73 error = SET_ERROR(EEXIST);
74 else if (error == ENOENT)
82 dsl_dataset_user_hold_check(void *arg, dmu_tx_t *tx)
84 dsl_dataset_user_hold_arg_t *dduha = arg;
85 dsl_pool_t *dp = dmu_tx_pool(tx);
88 if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS)
89 return (SET_ERROR(ENOTSUP));
91 if (!dmu_tx_is_syncing(tx))
94 for (pair = nvlist_next_nvpair(dduha->dduha_holds, NULL);
95 pair != NULL; pair = nvlist_next_nvpair(dduha->dduha_holds, pair)) {
100 /* must be a snapshot */
101 name = nvpair_name(pair);
102 if (strchr(name, '@') == NULL)
103 error = SET_ERROR(EINVAL);
106 error = nvpair_value_string(pair, &htag);
109 error = dsl_dataset_hold(dp, name, FTAG, &ds);
112 error = dsl_dataset_user_hold_check_one(ds, htag,
113 dduha->dduha_minor != 0, tx);
114 dsl_dataset_rele(ds, FTAG);
118 fnvlist_add_string(dduha->dduha_chkholds, name, htag);
121 * We register ENOENT errors so they can be correctly
122 * reported if needed, such as when all holds fail.
124 fnvlist_add_int32(dduha->dduha_errlist, name, error);
135 dsl_dataset_user_hold_sync_one_impl(nvlist_t *tmpholds, dsl_dataset_t *ds,
136 const char *htag, minor_t minor, uint64_t now, dmu_tx_t *tx)
138 dsl_pool_t *dp = ds->ds_dir->dd_pool;
139 objset_t *mos = dp->dp_meta_objset;
142 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
144 if (dsl_dataset_phys(ds)->ds_userrefs_obj == 0) {
146 * This is the first user hold for this dataset. Create
147 * the userrefs zap object.
149 dmu_buf_will_dirty(ds->ds_dbuf, tx);
150 zapobj = dsl_dataset_phys(ds)->ds_userrefs_obj =
151 zap_create(mos, DMU_OT_USERREFS, DMU_OT_NONE, 0, tx);
153 zapobj = dsl_dataset_phys(ds)->ds_userrefs_obj;
157 VERIFY0(zap_add(mos, zapobj, htag, 8, 1, &now, tx));
160 char name[MAXNAMELEN];
163 VERIFY0(dsl_pool_user_hold(dp, ds->ds_object,
165 (void) snprintf(name, sizeof (name), "%llx",
166 (u_longlong_t)ds->ds_object);
168 if (nvlist_lookup_nvlist(tmpholds, name, &tags) != 0) {
169 tags = fnvlist_alloc();
170 fnvlist_add_boolean(tags, htag);
171 fnvlist_add_nvlist(tmpholds, name, tags);
174 fnvlist_add_boolean(tags, htag);
178 spa_history_log_internal_ds(ds, "hold", tx,
179 "tag=%s temp=%d refs=%llu",
180 htag, minor != 0, ds->ds_userrefs);
183 typedef struct zfs_hold_cleanup_arg {
184 char zhca_spaname[MAXNAMELEN];
185 uint64_t zhca_spa_load_guid;
186 nvlist_t *zhca_holds;
187 } zfs_hold_cleanup_arg_t;
190 dsl_dataset_user_release_onexit(void *arg)
192 zfs_hold_cleanup_arg_t *ca = arg;
196 error = spa_open(ca->zhca_spaname, &spa, FTAG);
198 zfs_dbgmsg("couldn't release holds on pool=%s "
199 "because pool is no longer loaded",
203 if (spa_load_guid(spa) != ca->zhca_spa_load_guid) {
204 zfs_dbgmsg("couldn't release holds on pool=%s "
205 "because pool is no longer loaded (guid doesn't match)",
207 spa_close(spa, FTAG);
211 (void) dsl_dataset_user_release_tmp(spa_get_dsl(spa), ca->zhca_holds);
212 fnvlist_free(ca->zhca_holds);
213 kmem_free(ca, sizeof (zfs_hold_cleanup_arg_t));
214 spa_close(spa, FTAG);
218 dsl_onexit_hold_cleanup(spa_t *spa, nvlist_t *holds, minor_t minor)
220 zfs_hold_cleanup_arg_t *ca;
222 if (minor == 0 || nvlist_empty(holds)) {
228 ca = kmem_alloc(sizeof (*ca), KM_SLEEP);
230 (void) strlcpy(ca->zhca_spaname, spa_name(spa),
231 sizeof (ca->zhca_spaname));
232 ca->zhca_spa_load_guid = spa_load_guid(spa);
233 ca->zhca_holds = holds;
234 VERIFY0(zfs_onexit_add_cb(minor,
235 dsl_dataset_user_release_onexit, ca, NULL));
239 dsl_dataset_user_hold_sync_one(dsl_dataset_t *ds, const char *htag,
240 minor_t minor, uint64_t now, dmu_tx_t *tx)
245 tmpholds = fnvlist_alloc();
248 dsl_dataset_user_hold_sync_one_impl(tmpholds, ds, htag, minor, now, tx);
249 dsl_onexit_hold_cleanup(dsl_dataset_get_spa(ds), tmpholds, minor);
253 dsl_dataset_user_hold_sync(void *arg, dmu_tx_t *tx)
255 dsl_dataset_user_hold_arg_t *dduha = arg;
256 dsl_pool_t *dp = dmu_tx_pool(tx);
259 uint64_t now = gethrestime_sec();
261 if (dduha->dduha_minor != 0)
262 tmpholds = fnvlist_alloc();
265 for (pair = nvlist_next_nvpair(dduha->dduha_chkholds, NULL);
267 pair = nvlist_next_nvpair(dduha->dduha_chkholds, pair)) {
270 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
271 dsl_dataset_user_hold_sync_one_impl(tmpholds, ds,
272 fnvpair_value_string(pair), dduha->dduha_minor, now, tx);
273 dsl_dataset_rele(ds, FTAG);
275 dsl_onexit_hold_cleanup(dp->dp_spa, tmpholds, dduha->dduha_minor);
279 * The full semantics of this function are described in the comment above
283 * holds is nvl of snapname -> holdname
284 * errlist will be filled in with snapname -> error
286 * The snaphosts must all be in the same pool.
288 * Holds for snapshots that don't exist will be skipped.
290 * If none of the snapshots for requested holds exist then ENOENT will be
293 * If cleanup_minor is not 0, the holds will be temporary, which will be cleaned
294 * up when the process exits.
296 * On success all the holds, for snapshots that existed, will be created and 0
299 * On failure no holds will be created, the errlist will be filled in,
300 * and an errno will returned.
302 * In all cases the errlist will contain entries for holds where the snapshot
306 dsl_dataset_user_hold(nvlist_t *holds, minor_t cleanup_minor, nvlist_t *errlist)
308 dsl_dataset_user_hold_arg_t dduha;
312 pair = nvlist_next_nvpair(holds, NULL);
316 dduha.dduha_holds = holds;
317 dduha.dduha_chkholds = fnvlist_alloc();
318 dduha.dduha_errlist = errlist;
319 dduha.dduha_minor = cleanup_minor;
321 ret = dsl_sync_task(nvpair_name(pair), dsl_dataset_user_hold_check,
322 dsl_dataset_user_hold_sync, &dduha,
323 fnvlist_num_pairs(holds), ZFS_SPACE_CHECK_RESERVED);
324 fnvlist_free(dduha.dduha_chkholds);
329 typedef int (dsl_holdfunc_t)(dsl_pool_t *dp, const char *name, void *tag,
330 dsl_dataset_t **dsp);
332 typedef struct dsl_dataset_user_release_arg {
333 dsl_holdfunc_t *ddura_holdfunc;
334 nvlist_t *ddura_holds;
335 nvlist_t *ddura_todelete;
336 nvlist_t *ddura_errlist;
337 nvlist_t *ddura_chkholds;
338 } dsl_dataset_user_release_arg_t;
340 /* Place a dataset hold on the snapshot identified by passed dsobj string */
342 dsl_dataset_hold_obj_string(dsl_pool_t *dp, const char *dsobj, void *tag,
345 return (dsl_dataset_hold_obj(dp, strtonum(dsobj, NULL), tag, dsp));
349 dsl_dataset_user_release_check_one(dsl_dataset_user_release_arg_t *ddura,
350 dsl_dataset_t *ds, nvlist_t *holds, const char *snapname)
353 nvlist_t *holds_found;
358 if (!ds->ds_is_snapshot)
359 return (SET_ERROR(EINVAL));
361 if (nvlist_empty(holds))
365 mos = ds->ds_dir->dd_pool->dp_meta_objset;
366 zapobj = dsl_dataset_phys(ds)->ds_userrefs_obj;
367 VERIFY0(nvlist_alloc(&holds_found, NV_UNIQUE_NAME, KM_SLEEP));
369 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
370 pair = nvlist_next_nvpair(holds, pair)) {
373 const char *holdname = nvpair_name(pair);
376 error = zap_lookup(mos, zapobj, holdname, 8, 1, &tmp);
378 error = SET_ERROR(ENOENT);
381 * Non-existent holds are put on the errlist, but don't
382 * cause an overall failure.
384 if (error == ENOENT) {
385 if (ddura->ddura_errlist != NULL) {
386 char *errtag = kmem_asprintf("%s#%s",
388 fnvlist_add_int32(ddura->ddura_errlist, errtag,
396 fnvlist_free(holds_found);
400 fnvlist_add_boolean(holds_found, holdname);
404 if (DS_IS_DEFER_DESTROY(ds) &&
405 dsl_dataset_phys(ds)->ds_num_children == 1 &&
406 ds->ds_userrefs == numholds) {
407 /* we need to destroy the snapshot as well */
408 if (dsl_dataset_long_held(ds)) {
409 fnvlist_free(holds_found);
410 return (SET_ERROR(EBUSY));
412 fnvlist_add_boolean(ddura->ddura_todelete, snapname);
416 fnvlist_add_nvlist(ddura->ddura_chkholds, snapname,
419 fnvlist_free(holds_found);
425 dsl_dataset_user_release_check(void *arg, dmu_tx_t *tx)
427 dsl_dataset_user_release_arg_t *ddura;
428 dsl_holdfunc_t *holdfunc;
432 if (!dmu_tx_is_syncing(tx))
435 dp = dmu_tx_pool(tx);
437 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
440 holdfunc = ddura->ddura_holdfunc;
442 for (pair = nvlist_next_nvpair(ddura->ddura_holds, NULL);
443 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
447 const char *snapname = nvpair_name(pair);
449 error = nvpair_value_nvlist(pair, &holds);
451 error = (SET_ERROR(EINVAL));
453 error = holdfunc(dp, snapname, FTAG, &ds);
455 error = dsl_dataset_user_release_check_one(ddura, ds,
457 dsl_dataset_rele(ds, FTAG);
460 if (ddura->ddura_errlist != NULL) {
461 fnvlist_add_int32(ddura->ddura_errlist,
465 * Non-existent snapshots are put on the errlist,
466 * but don't cause an overall failure.
477 dsl_dataset_user_release_sync_one(dsl_dataset_t *ds, nvlist_t *holds,
480 dsl_pool_t *dp = ds->ds_dir->dd_pool;
481 objset_t *mos = dp->dp_meta_objset;
484 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
485 pair = nvlist_next_nvpair(holds, pair)) {
487 const char *holdname = nvpair_name(pair);
489 /* Remove temporary hold if one exists. */
490 error = dsl_pool_user_release(dp, ds->ds_object, holdname, tx);
491 VERIFY(error == 0 || error == ENOENT);
493 VERIFY0(zap_remove(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
497 spa_history_log_internal_ds(ds, "release", tx,
498 "tag=%s refs=%lld", holdname, (longlong_t)ds->ds_userrefs);
503 dsl_dataset_user_release_sync(void *arg, dmu_tx_t *tx)
505 dsl_dataset_user_release_arg_t *ddura = arg;
506 dsl_holdfunc_t *holdfunc = ddura->ddura_holdfunc;
507 dsl_pool_t *dp = dmu_tx_pool(tx);
510 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
512 for (pair = nvlist_next_nvpair(ddura->ddura_chkholds, NULL);
513 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_chkholds,
516 const char *name = nvpair_name(pair);
518 VERIFY0(holdfunc(dp, name, FTAG, &ds));
520 dsl_dataset_user_release_sync_one(ds,
521 fnvpair_value_nvlist(pair), tx);
522 if (nvlist_exists(ddura->ddura_todelete, name)) {
523 ASSERT(ds->ds_userrefs == 0 &&
524 dsl_dataset_phys(ds)->ds_num_children == 1 &&
525 DS_IS_DEFER_DESTROY(ds));
526 dsl_destroy_snapshot_sync_impl(ds, B_FALSE, tx);
528 dsl_dataset_rele(ds, FTAG);
533 * The full semantics of this function are described in the comment above
537 * Releases holds specified in the nvl holds.
539 * holds is nvl of snapname -> { holdname, ... }
540 * errlist will be filled in with snapname -> error
542 * If tmpdp is not NULL the names for holds should be the dsobj's of snapshots,
543 * otherwise they should be the names of shapshots.
545 * As a release may cause snapshots to be destroyed this trys to ensure they
548 * The release of non-existent holds are skipped.
550 * At least one hold must have been released for the this function to succeed
554 dsl_dataset_user_release_impl(nvlist_t *holds, nvlist_t *errlist,
557 dsl_dataset_user_release_arg_t ddura;
562 pair = nvlist_next_nvpair(holds, NULL);
567 * The release may cause snapshots to be destroyed; make sure they
571 /* Temporary holds are specified by dsobj string. */
572 ddura.ddura_holdfunc = dsl_dataset_hold_obj_string;
573 pool = spa_name(tmpdp->dp_spa);
575 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
576 pair = nvlist_next_nvpair(holds, pair)) {
579 dsl_pool_config_enter(tmpdp, FTAG);
580 error = dsl_dataset_hold_obj_string(tmpdp,
581 nvpair_name(pair), FTAG, &ds);
583 char name[MAXNAMELEN];
584 dsl_dataset_name(ds, name);
585 dsl_pool_config_exit(tmpdp, FTAG);
586 dsl_dataset_rele(ds, FTAG);
587 (void) zfs_unmount_snap(name);
589 dsl_pool_config_exit(tmpdp, FTAG);
594 /* Non-temporary holds are specified by name. */
595 ddura.ddura_holdfunc = dsl_dataset_hold;
596 pool = nvpair_name(pair);
598 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
599 pair = nvlist_next_nvpair(holds, pair)) {
600 (void) zfs_unmount_snap(nvpair_name(pair));
605 ddura.ddura_holds = holds;
606 ddura.ddura_errlist = errlist;
607 VERIFY0(nvlist_alloc(&ddura.ddura_todelete, NV_UNIQUE_NAME,
609 VERIFY0(nvlist_alloc(&ddura.ddura_chkholds, NV_UNIQUE_NAME,
612 error = dsl_sync_task(pool, dsl_dataset_user_release_check,
613 dsl_dataset_user_release_sync, &ddura, 0, ZFS_SPACE_CHECK_NONE);
614 fnvlist_free(ddura.ddura_todelete);
615 fnvlist_free(ddura.ddura_chkholds);
621 * holds is nvl of snapname -> { holdname, ... }
622 * errlist will be filled in with snapname -> error
625 dsl_dataset_user_release(nvlist_t *holds, nvlist_t *errlist)
627 return (dsl_dataset_user_release_impl(holds, errlist, NULL));
631 * holds is nvl of snapdsobj -> { holdname, ... }
634 dsl_dataset_user_release_tmp(struct dsl_pool *dp, nvlist_t *holds)
637 (void) dsl_dataset_user_release_impl(holds, NULL, dp);
641 dsl_dataset_get_holds(const char *dsname, nvlist_t *nvl)
647 err = dsl_pool_hold(dsname, FTAG, &dp);
650 err = dsl_dataset_hold(dp, dsname, FTAG, &ds);
652 dsl_pool_rele(dp, FTAG);
656 if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
660 za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
661 for (zap_cursor_init(&zc, ds->ds_dir->dd_pool->dp_meta_objset,
662 dsl_dataset_phys(ds)->ds_userrefs_obj);
663 zap_cursor_retrieve(&zc, za) == 0;
664 zap_cursor_advance(&zc)) {
665 fnvlist_add_uint64(nvl, za->za_name,
666 za->za_first_integer);
668 zap_cursor_fini(&zc);
669 kmem_free(za, sizeof (zap_attribute_t));
671 dsl_dataset_rele(ds, FTAG);
672 dsl_pool_rele(dp, FTAG);