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) 2013 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 && ds->ds_phys->ds_userrefs_obj != 0) {
70 error = zap_lookup(mos, ds->ds_phys->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);
87 if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS)
88 return (SET_ERROR(ENOTSUP));
90 if (!dmu_tx_is_syncing(tx))
93 for (nvpair_t *pair = nvlist_next_nvpair(dduha->dduha_holds, NULL);
94 pair != NULL; pair = nvlist_next_nvpair(dduha->dduha_holds, pair)) {
99 /* must be a snapshot */
100 name = nvpair_name(pair);
101 if (strchr(name, '@') == NULL)
102 error = SET_ERROR(EINVAL);
105 error = nvpair_value_string(pair, &htag);
108 error = dsl_dataset_hold(dp, name, FTAG, &ds);
111 error = dsl_dataset_user_hold_check_one(ds, htag,
112 dduha->dduha_minor != 0, tx);
113 dsl_dataset_rele(ds, FTAG);
117 fnvlist_add_string(dduha->dduha_chkholds, name, htag);
120 * We register ENOENT errors so they can be correctly
121 * reported if needed, such as when all holds fail.
123 fnvlist_add_int32(dduha->dduha_errlist, name, error);
134 dsl_dataset_user_hold_sync_one_impl(nvlist_t *tmpholds, dsl_dataset_t *ds,
135 const char *htag, minor_t minor, uint64_t now, dmu_tx_t *tx)
137 dsl_pool_t *dp = ds->ds_dir->dd_pool;
138 objset_t *mos = dp->dp_meta_objset;
141 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
143 if (ds->ds_phys->ds_userrefs_obj == 0) {
145 * This is the first user hold for this dataset. Create
146 * the userrefs zap object.
148 dmu_buf_will_dirty(ds->ds_dbuf, tx);
149 zapobj = ds->ds_phys->ds_userrefs_obj =
150 zap_create(mos, DMU_OT_USERREFS, DMU_OT_NONE, 0, tx);
152 zapobj = ds->ds_phys->ds_userrefs_obj;
156 VERIFY0(zap_add(mos, zapobj, htag, 8, 1, &now, tx));
159 char name[MAXNAMELEN];
162 VERIFY0(dsl_pool_user_hold(dp, ds->ds_object,
164 (void) snprintf(name, sizeof (name), "%llx",
165 (u_longlong_t)ds->ds_object);
167 if (nvlist_lookup_nvlist(tmpholds, name, &tags) != 0) {
168 tags = fnvlist_alloc();
169 fnvlist_add_boolean(tags, htag);
170 fnvlist_add_nvlist(tmpholds, name, tags);
173 fnvlist_add_boolean(tags, htag);
177 spa_history_log_internal_ds(ds, "hold", tx,
178 "tag=%s temp=%d refs=%llu",
179 htag, minor != 0, ds->ds_userrefs);
182 typedef struct zfs_hold_cleanup_arg {
183 char zhca_spaname[MAXNAMELEN];
184 uint64_t zhca_spa_load_guid;
185 nvlist_t *zhca_holds;
186 } zfs_hold_cleanup_arg_t;
189 dsl_dataset_user_release_onexit(void *arg)
191 zfs_hold_cleanup_arg_t *ca = arg;
195 error = spa_open(ca->zhca_spaname, &spa, FTAG);
197 zfs_dbgmsg("couldn't release holds on pool=%s "
198 "because pool is no longer loaded",
202 if (spa_load_guid(spa) != ca->zhca_spa_load_guid) {
203 zfs_dbgmsg("couldn't release holds on pool=%s "
204 "because pool is no longer loaded (guid doesn't match)",
206 spa_close(spa, FTAG);
210 (void) dsl_dataset_user_release_tmp(spa_get_dsl(spa), ca->zhca_holds);
211 fnvlist_free(ca->zhca_holds);
212 kmem_free(ca, sizeof (zfs_hold_cleanup_arg_t));
213 spa_close(spa, FTAG);
217 dsl_onexit_hold_cleanup(spa_t *spa, nvlist_t *holds, minor_t minor)
219 zfs_hold_cleanup_arg_t *ca;
221 if (minor == 0 || nvlist_empty(holds)) {
227 ca = kmem_alloc(sizeof (*ca), KM_SLEEP);
229 (void) strlcpy(ca->zhca_spaname, spa_name(spa),
230 sizeof (ca->zhca_spaname));
231 ca->zhca_spa_load_guid = spa_load_guid(spa);
232 ca->zhca_holds = holds;
233 VERIFY0(zfs_onexit_add_cb(minor,
234 dsl_dataset_user_release_onexit, ca, NULL));
238 dsl_dataset_user_hold_sync_one(dsl_dataset_t *ds, const char *htag,
239 minor_t minor, uint64_t now, dmu_tx_t *tx)
244 tmpholds = fnvlist_alloc();
247 dsl_dataset_user_hold_sync_one_impl(tmpholds, ds, htag, minor, now, tx);
248 dsl_onexit_hold_cleanup(dsl_dataset_get_spa(ds), tmpholds, minor);
252 dsl_dataset_user_hold_sync(void *arg, dmu_tx_t *tx)
254 dsl_dataset_user_hold_arg_t *dduha = arg;
255 dsl_pool_t *dp = dmu_tx_pool(tx);
257 uint64_t now = gethrestime_sec();
259 if (dduha->dduha_minor != 0)
260 tmpholds = fnvlist_alloc();
263 for (nvpair_t *pair = nvlist_next_nvpair(dduha->dduha_chkholds, NULL);
265 pair = nvlist_next_nvpair(dduha->dduha_chkholds, pair)) {
268 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
269 dsl_dataset_user_hold_sync_one_impl(tmpholds, ds,
270 fnvpair_value_string(pair), dduha->dduha_minor, now, tx);
271 dsl_dataset_rele(ds, FTAG);
273 dsl_onexit_hold_cleanup(dp->dp_spa, tmpholds, dduha->dduha_minor);
277 * The full semantics of this function are described in the comment above
281 * holds is nvl of snapname -> holdname
282 * errlist will be filled in with snapname -> error
284 * The snaphosts must all be in the same pool.
286 * Holds for snapshots that don't exist will be skipped.
288 * If none of the snapshots for requested holds exist then ENOENT will be
291 * If cleanup_minor is not 0, the holds will be temporary, which will be cleaned
292 * up when the process exits.
294 * On success all the holds, for snapshots that existed, will be created and 0
297 * On failure no holds will be created, the errlist will be filled in,
298 * and an errno will returned.
300 * In all cases the errlist will contain entries for holds where the snapshot
304 dsl_dataset_user_hold(nvlist_t *holds, minor_t cleanup_minor, nvlist_t *errlist)
306 dsl_dataset_user_hold_arg_t dduha;
310 pair = nvlist_next_nvpair(holds, NULL);
314 dduha.dduha_holds = holds;
315 dduha.dduha_chkholds = fnvlist_alloc();
316 dduha.dduha_errlist = errlist;
317 dduha.dduha_minor = cleanup_minor;
319 ret = dsl_sync_task(nvpair_name(pair), dsl_dataset_user_hold_check,
320 dsl_dataset_user_hold_sync, &dduha, fnvlist_num_pairs(holds));
321 fnvlist_free(dduha.dduha_chkholds);
326 typedef int (dsl_holdfunc_t)(dsl_pool_t *dp, const char *name, void *tag,
327 dsl_dataset_t **dsp);
329 typedef struct dsl_dataset_user_release_arg {
330 dsl_holdfunc_t *ddura_holdfunc;
331 nvlist_t *ddura_holds;
332 nvlist_t *ddura_todelete;
333 nvlist_t *ddura_errlist;
334 nvlist_t *ddura_chkholds;
335 } dsl_dataset_user_release_arg_t;
337 /* Place a dataset hold on the snapshot identified by passed dsobj string */
339 dsl_dataset_hold_obj_string(dsl_pool_t *dp, const char *dsobj, void *tag,
342 return (dsl_dataset_hold_obj(dp, strtonum(dsobj, NULL), tag, dsp));
346 dsl_dataset_user_release_check_one(dsl_dataset_user_release_arg_t *ddura,
347 dsl_dataset_t *ds, nvlist_t *holds, const char *snapname)
350 nvlist_t *holds_found;
354 if (!dsl_dataset_is_snapshot(ds))
355 return (SET_ERROR(EINVAL));
357 if (nvlist_empty(holds))
361 mos = ds->ds_dir->dd_pool->dp_meta_objset;
362 zapobj = ds->ds_phys->ds_userrefs_obj;
363 holds_found = fnvlist_alloc();
365 for (nvpair_t *pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
366 pair = nvlist_next_nvpair(holds, pair)) {
369 const char *holdname = nvpair_name(pair);
372 error = zap_lookup(mos, zapobj, holdname, 8, 1, &tmp);
374 error = SET_ERROR(ENOENT);
377 * Non-existent holds are put on the errlist, but don't
378 * cause an overall failure.
380 if (error == ENOENT) {
381 if (ddura->ddura_errlist != NULL) {
382 char *errtag = kmem_asprintf("%s#%s",
384 fnvlist_add_int32(ddura->ddura_errlist, errtag,
392 fnvlist_free(holds_found);
396 fnvlist_add_boolean(holds_found, holdname);
400 if (DS_IS_DEFER_DESTROY(ds) && ds->ds_phys->ds_num_children == 1 &&
401 ds->ds_userrefs == numholds) {
402 /* we need to destroy the snapshot as well */
403 if (dsl_dataset_long_held(ds)) {
404 fnvlist_free(holds_found);
405 return (SET_ERROR(EBUSY));
407 fnvlist_add_boolean(ddura->ddura_todelete, snapname);
411 fnvlist_add_nvlist(ddura->ddura_chkholds, snapname,
414 fnvlist_free(holds_found);
420 dsl_dataset_user_release_check(void *arg, dmu_tx_t *tx)
422 dsl_dataset_user_release_arg_t *ddura;
423 dsl_holdfunc_t *holdfunc;
426 if (!dmu_tx_is_syncing(tx))
429 dp = dmu_tx_pool(tx);
431 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
434 holdfunc = ddura->ddura_holdfunc;
436 for (nvpair_t *pair = nvlist_next_nvpair(ddura->ddura_holds, NULL);
437 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
441 const char *snapname = nvpair_name(pair);
443 error = nvpair_value_nvlist(pair, &holds);
445 error = (SET_ERROR(EINVAL));
447 error = holdfunc(dp, snapname, FTAG, &ds);
449 error = dsl_dataset_user_release_check_one(ddura, ds,
451 dsl_dataset_rele(ds, FTAG);
454 if (ddura->ddura_errlist != NULL) {
455 fnvlist_add_int32(ddura->ddura_errlist,
459 * Non-existent snapshots are put on the errlist,
460 * but don't cause an overall failure.
471 dsl_dataset_user_release_sync_one(dsl_dataset_t *ds, nvlist_t *holds,
474 dsl_pool_t *dp = ds->ds_dir->dd_pool;
475 objset_t *mos = dp->dp_meta_objset;
477 for (nvpair_t *pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
478 pair = nvlist_next_nvpair(holds, pair)) {
480 const char *holdname = nvpair_name(pair);
482 /* Remove temporary hold if one exists. */
483 error = dsl_pool_user_release(dp, ds->ds_object, holdname, tx);
484 VERIFY(error == 0 || error == ENOENT);
486 VERIFY0(zap_remove(mos, ds->ds_phys->ds_userrefs_obj, holdname,
490 spa_history_log_internal_ds(ds, "release", tx,
491 "tag=%s refs=%lld", holdname, (longlong_t)ds->ds_userrefs);
496 dsl_dataset_user_release_sync(void *arg, dmu_tx_t *tx)
498 dsl_dataset_user_release_arg_t *ddura = arg;
499 dsl_holdfunc_t *holdfunc = ddura->ddura_holdfunc;
500 dsl_pool_t *dp = dmu_tx_pool(tx);
502 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
504 for (nvpair_t *pair = nvlist_next_nvpair(ddura->ddura_chkholds, NULL);
505 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_chkholds,
508 const char *name = nvpair_name(pair);
510 VERIFY0(holdfunc(dp, name, FTAG, &ds));
512 dsl_dataset_user_release_sync_one(ds,
513 fnvpair_value_nvlist(pair), tx);
514 if (nvlist_exists(ddura->ddura_todelete, name)) {
515 ASSERT(ds->ds_userrefs == 0 &&
516 ds->ds_phys->ds_num_children == 1 &&
517 DS_IS_DEFER_DESTROY(ds));
518 dsl_destroy_snapshot_sync_impl(ds, B_FALSE, tx);
520 dsl_dataset_rele(ds, FTAG);
525 * The full semantics of this function are described in the comment above
529 * Releases holds specified in the nvl holds.
531 * holds is nvl of snapname -> { holdname, ... }
532 * errlist will be filled in with snapname -> error
534 * If tmpdp is not NULL the names for holds should be the dsobj's of snapshots,
535 * otherwise they should be the names of shapshots.
537 * As a release may cause snapshots to be destroyed this trys to ensure they
540 * The release of non-existent holds are skipped.
542 * At least one hold must have been released for the this function to succeed
546 dsl_dataset_user_release_impl(nvlist_t *holds, nvlist_t *errlist,
549 dsl_dataset_user_release_arg_t ddura;
554 pair = nvlist_next_nvpair(holds, NULL);
559 * The release may cause snapshots to be destroyed; make sure they
563 /* Temporary holds are specified by dsobj string. */
564 ddura.ddura_holdfunc = dsl_dataset_hold_obj_string;
565 pool = spa_name(tmpdp->dp_spa);
567 dsl_pool_config_enter(tmpdp, FTAG);
568 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
569 pair = nvlist_next_nvpair(holds, pair)) {
572 error = dsl_dataset_hold_obj_string(tmpdp,
573 nvpair_name(pair), FTAG, &ds);
575 char name[MAXNAMELEN];
576 dsl_dataset_name(ds, name);
577 dsl_dataset_rele(ds, FTAG);
578 (void) zfs_unmount_snap(name);
581 dsl_pool_config_exit(tmpdp, FTAG);
584 /* Non-temporary holds are specified by name. */
585 ddura.ddura_holdfunc = dsl_dataset_hold;
586 pool = nvpair_name(pair);
588 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
589 pair = nvlist_next_nvpair(holds, pair)) {
590 (void) zfs_unmount_snap(nvpair_name(pair));
595 ddura.ddura_holds = holds;
596 ddura.ddura_errlist = errlist;
597 ddura.ddura_todelete = fnvlist_alloc();
598 ddura.ddura_chkholds = fnvlist_alloc();
600 error = dsl_sync_task(pool, dsl_dataset_user_release_check,
601 dsl_dataset_user_release_sync, &ddura,
602 fnvlist_num_pairs(holds));
603 fnvlist_free(ddura.ddura_todelete);
604 fnvlist_free(ddura.ddura_chkholds);
610 * holds is nvl of snapname -> { holdname, ... }
611 * errlist will be filled in with snapname -> error
614 dsl_dataset_user_release(nvlist_t *holds, nvlist_t *errlist)
616 return (dsl_dataset_user_release_impl(holds, errlist, NULL));
620 * holds is nvl of snapdsobj -> { holdname, ... }
623 dsl_dataset_user_release_tmp(struct dsl_pool *dp, nvlist_t *holds)
626 (void) dsl_dataset_user_release_impl(holds, NULL, dp);
630 dsl_dataset_get_holds(const char *dsname, nvlist_t *nvl)
636 err = dsl_pool_hold(dsname, FTAG, &dp);
639 err = dsl_dataset_hold(dp, dsname, FTAG, &ds);
641 dsl_pool_rele(dp, FTAG);
645 if (ds->ds_phys->ds_userrefs_obj != 0) {
649 za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
650 for (zap_cursor_init(&zc, ds->ds_dir->dd_pool->dp_meta_objset,
651 ds->ds_phys->ds_userrefs_obj);
652 zap_cursor_retrieve(&zc, za) == 0;
653 zap_cursor_advance(&zc)) {
654 fnvlist_add_uint64(nvl, za->za_name,
655 za->za_first_integer);
657 zap_cursor_fini(&zc);
658 kmem_free(za, sizeof (zap_attribute_t));
660 dsl_dataset_rele(ds, FTAG);
661 dsl_pool_rele(dp, FTAG);