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 */
26
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>
37 #include <sys/zap.h>
38
39 typedef struct dsl_dataset_user_hold_arg {
40 nvlist_t *dduha_holds;
41 nvlist_t *dduha_chkholds;
42 nvlist_t *dduha_errlist;
43 minor_t dduha_minor;
44 } dsl_dataset_user_hold_arg_t;
45
46 /*
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.
49 */
50 int
dsl_dataset_user_hold_check_one(dsl_dataset_t * ds,const char * htag,boolean_t temphold,dmu_tx_t * tx)51 dsl_dataset_user_hold_check_one(dsl_dataset_t *ds, const char *htag,
52 boolean_t temphold, dmu_tx_t *tx)
53 {
54 dsl_pool_t *dp = dmu_tx_pool(tx);
55 objset_t *mos = dp->dp_meta_objset;
56 int error = 0;
57
58 ASSERT(dsl_pool_config_held(dp));
59
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));
65
66 /* tags must be unique (if ds already exists) */
67 if (ds != NULL && dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
68 uint64_t value;
69
70 error = zap_lookup(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
71 htag, 8, 1, &value);
72 if (error == 0)
73 error = SET_ERROR(EEXIST);
74 else if (error == ENOENT)
75 error = 0;
76 }
77
78 return (error);
79 }
80
81 static int
dsl_dataset_user_hold_check(void * arg,dmu_tx_t * tx)82 dsl_dataset_user_hold_check(void *arg, dmu_tx_t *tx)
83 {
84 dsl_dataset_user_hold_arg_t *dduha = arg;
85 dsl_pool_t *dp = dmu_tx_pool(tx);
86
87 if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS)
88 return (SET_ERROR(ENOTSUP));
89
90 if (!dmu_tx_is_syncing(tx))
91 return (0);
92
93 for (nvpair_t *pair = nvlist_next_nvpair(dduha->dduha_holds, NULL);
94 pair != NULL; pair = nvlist_next_nvpair(dduha->dduha_holds, pair)) {
95 dsl_dataset_t *ds;
96 int error = 0;
97 char *htag, *name;
98
99 /* must be a snapshot */
100 name = nvpair_name(pair);
101 if (strchr(name, '@') == NULL)
102 error = SET_ERROR(EINVAL);
103
104 if (error == 0)
105 error = nvpair_value_string(pair, &htag);
106
107 if (error == 0)
108 error = dsl_dataset_hold(dp, name, FTAG, &ds);
109
110 if (error == 0) {
111 error = dsl_dataset_user_hold_check_one(ds, htag,
112 dduha->dduha_minor != 0, tx);
113 dsl_dataset_rele(ds, FTAG);
114 }
115
116 if (error == 0) {
117 fnvlist_add_string(dduha->dduha_chkholds, name, htag);
118 } else {
119 /*
120 * We register ENOENT errors so they can be correctly
121 * reported if needed, such as when all holds fail.
122 */
123 fnvlist_add_int32(dduha->dduha_errlist, name, error);
124 if (error != ENOENT)
125 return (error);
126 }
127 }
128
129 return (0);
130 }
131
132
133 static void
dsl_dataset_user_hold_sync_one_impl(nvlist_t * tmpholds,dsl_dataset_t * ds,const char * htag,minor_t minor,uint64_t now,dmu_tx_t * tx)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)
136 {
137 dsl_pool_t *dp = ds->ds_dir->dd_pool;
138 objset_t *mos = dp->dp_meta_objset;
139 uint64_t zapobj;
140
141 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
142
143 if (dsl_dataset_phys(ds)->ds_userrefs_obj == 0) {
144 /*
145 * This is the first user hold for this dataset. Create
146 * the userrefs zap object.
147 */
148 dmu_buf_will_dirty(ds->ds_dbuf, tx);
149 zapobj = dsl_dataset_phys(ds)->ds_userrefs_obj =
150 zap_create(mos, DMU_OT_USERREFS, DMU_OT_NONE, 0, tx);
151 } else {
152 zapobj = dsl_dataset_phys(ds)->ds_userrefs_obj;
153 }
154 ds->ds_userrefs++;
155
156 VERIFY0(zap_add(mos, zapobj, htag, 8, 1, &now, tx));
157
158 if (minor != 0) {
159 char name[MAXNAMELEN];
160 nvlist_t *tags;
161
162 VERIFY0(dsl_pool_user_hold(dp, ds->ds_object,
163 htag, now, tx));
164 (void) snprintf(name, sizeof (name), "%llx",
165 (u_longlong_t)ds->ds_object);
166
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);
171 fnvlist_free(tags);
172 } else {
173 fnvlist_add_boolean(tags, htag);
174 }
175 }
176
177 spa_history_log_internal_ds(ds, "hold", tx,
178 "tag=%s temp=%d refs=%llu",
179 htag, minor != 0, ds->ds_userrefs);
180 }
181
182 typedef struct zfs_hold_cleanup_arg {
183 char zhca_spaname[ZFS_MAX_DATASET_NAME_LEN];
184 uint64_t zhca_spa_load_guid;
185 nvlist_t *zhca_holds;
186 } zfs_hold_cleanup_arg_t;
187
188 static void
dsl_dataset_user_release_onexit(void * arg)189 dsl_dataset_user_release_onexit(void *arg)
190 {
191 zfs_hold_cleanup_arg_t *ca = arg;
192 spa_t *spa;
193 int error;
194
195 error = spa_open(ca->zhca_spaname, &spa, FTAG);
196 if (error != 0) {
197 zfs_dbgmsg("couldn't release holds on pool=%s "
198 "because pool is no longer loaded",
199 ca->zhca_spaname);
200 return;
201 }
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)",
205 ca->zhca_spaname);
206 spa_close(spa, FTAG);
207 return;
208 }
209
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);
214 }
215
216 static void
dsl_onexit_hold_cleanup(spa_t * spa,nvlist_t * holds,minor_t minor)217 dsl_onexit_hold_cleanup(spa_t *spa, nvlist_t *holds, minor_t minor)
218 {
219 zfs_hold_cleanup_arg_t *ca;
220
221 if (minor == 0 || nvlist_empty(holds)) {
222 fnvlist_free(holds);
223 return;
224 }
225
226 ASSERT(spa != NULL);
227 ca = kmem_alloc(sizeof (*ca), KM_SLEEP);
228
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));
235 }
236
237 void
dsl_dataset_user_hold_sync_one(dsl_dataset_t * ds,const char * htag,minor_t minor,uint64_t now,dmu_tx_t * tx)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)
240 {
241 nvlist_t *tmpholds;
242
243 if (minor != 0)
244 tmpholds = fnvlist_alloc();
245 else
246 tmpholds = NULL;
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);
249 }
250
251 static void
dsl_dataset_user_hold_sync(void * arg,dmu_tx_t * tx)252 dsl_dataset_user_hold_sync(void *arg, dmu_tx_t *tx)
253 {
254 dsl_dataset_user_hold_arg_t *dduha = arg;
255 dsl_pool_t *dp = dmu_tx_pool(tx);
256 nvlist_t *tmpholds;
257 uint64_t now = gethrestime_sec();
258
259 if (dduha->dduha_minor != 0)
260 tmpholds = fnvlist_alloc();
261 else
262 tmpholds = NULL;
263 for (nvpair_t *pair = nvlist_next_nvpair(dduha->dduha_chkholds, NULL);
264 pair != NULL;
265 pair = nvlist_next_nvpair(dduha->dduha_chkholds, pair)) {
266 dsl_dataset_t *ds;
267
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);
272 }
273 dsl_onexit_hold_cleanup(dp->dp_spa, tmpholds, dduha->dduha_minor);
274 }
275
276 /*
277 * The full semantics of this function are described in the comment above
278 * lzc_hold().
279 *
280 * To summarize:
281 * holds is nvl of snapname -> holdname
282 * errlist will be filled in with snapname -> error
283 *
284 * The snaphosts must all be in the same pool.
285 *
286 * Holds for snapshots that don't exist will be skipped.
287 *
288 * If none of the snapshots for requested holds exist then ENOENT will be
289 * returned.
290 *
291 * If cleanup_minor is not 0, the holds will be temporary, which will be cleaned
292 * up when the process exits.
293 *
294 * On success all the holds, for snapshots that existed, will be created and 0
295 * will be returned.
296 *
297 * On failure no holds will be created, the errlist will be filled in,
298 * and an errno will returned.
299 *
300 * In all cases the errlist will contain entries for holds where the snapshot
301 * didn't exist.
302 */
303 int
dsl_dataset_user_hold(nvlist_t * holds,minor_t cleanup_minor,nvlist_t * errlist)304 dsl_dataset_user_hold(nvlist_t *holds, minor_t cleanup_minor, nvlist_t *errlist)
305 {
306 dsl_dataset_user_hold_arg_t dduha;
307 nvpair_t *pair;
308 int ret;
309
310 pair = nvlist_next_nvpair(holds, NULL);
311 if (pair == NULL)
312 return (0);
313
314 dduha.dduha_holds = holds;
315 dduha.dduha_chkholds = fnvlist_alloc();
316 dduha.dduha_errlist = errlist;
317 dduha.dduha_minor = cleanup_minor;
318
319 ret = dsl_sync_task(nvpair_name(pair), dsl_dataset_user_hold_check,
320 dsl_dataset_user_hold_sync, &dduha,
321 fnvlist_num_pairs(holds), ZFS_SPACE_CHECK_RESERVED);
322 fnvlist_free(dduha.dduha_chkholds);
323
324 return (ret);
325 }
326
327 typedef int (dsl_holdfunc_t)(dsl_pool_t *dp, const char *name, void *tag,
328 dsl_dataset_t **dsp);
329
330 typedef struct dsl_dataset_user_release_arg {
331 dsl_holdfunc_t *ddura_holdfunc;
332 nvlist_t *ddura_holds;
333 nvlist_t *ddura_todelete;
334 nvlist_t *ddura_errlist;
335 nvlist_t *ddura_chkholds;
336 } dsl_dataset_user_release_arg_t;
337
338 /* Place a dataset hold on the snapshot identified by passed dsobj string */
339 static int
dsl_dataset_hold_obj_string(dsl_pool_t * dp,const char * dsobj,void * tag,dsl_dataset_t ** dsp)340 dsl_dataset_hold_obj_string(dsl_pool_t *dp, const char *dsobj, void *tag,
341 dsl_dataset_t **dsp)
342 {
343 return (dsl_dataset_hold_obj(dp, strtonum(dsobj, NULL), tag, dsp));
344 }
345
346 static int
dsl_dataset_user_release_check_one(dsl_dataset_user_release_arg_t * ddura,dsl_dataset_t * ds,nvlist_t * holds,const char * snapname)347 dsl_dataset_user_release_check_one(dsl_dataset_user_release_arg_t *ddura,
348 dsl_dataset_t *ds, nvlist_t *holds, const char *snapname)
349 {
350 uint64_t zapobj;
351 nvlist_t *holds_found;
352 objset_t *mos;
353 int numholds;
354
355 if (!ds->ds_is_snapshot)
356 return (SET_ERROR(EINVAL));
357
358 if (nvlist_empty(holds))
359 return (0);
360
361 numholds = 0;
362 mos = ds->ds_dir->dd_pool->dp_meta_objset;
363 zapobj = dsl_dataset_phys(ds)->ds_userrefs_obj;
364 holds_found = fnvlist_alloc();
365
366 for (nvpair_t *pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
367 pair = nvlist_next_nvpair(holds, pair)) {
368 uint64_t tmp;
369 int error;
370 const char *holdname = nvpair_name(pair);
371
372 if (zapobj != 0)
373 error = zap_lookup(mos, zapobj, holdname, 8, 1, &tmp);
374 else
375 error = SET_ERROR(ENOENT);
376
377 /*
378 * Non-existent holds are put on the errlist, but don't
379 * cause an overall failure.
380 */
381 if (error == ENOENT) {
382 if (ddura->ddura_errlist != NULL) {
383 char *errtag = kmem_asprintf("%s#%s",
384 snapname, holdname);
385 fnvlist_add_int32(ddura->ddura_errlist, errtag,
386 ENOENT);
387 strfree(errtag);
388 }
389 continue;
390 }
391
392 if (error != 0) {
393 fnvlist_free(holds_found);
394 return (error);
395 }
396
397 fnvlist_add_boolean(holds_found, holdname);
398 numholds++;
399 }
400
401 if (DS_IS_DEFER_DESTROY(ds) &&
402 dsl_dataset_phys(ds)->ds_num_children == 1 &&
403 ds->ds_userrefs == numholds) {
404 /* we need to destroy the snapshot as well */
405 if (dsl_dataset_long_held(ds)) {
406 fnvlist_free(holds_found);
407 return (SET_ERROR(EBUSY));
408 }
409 fnvlist_add_boolean(ddura->ddura_todelete, snapname);
410 }
411
412 if (numholds != 0) {
413 fnvlist_add_nvlist(ddura->ddura_chkholds, snapname,
414 holds_found);
415 }
416 fnvlist_free(holds_found);
417
418 return (0);
419 }
420
421 static int
dsl_dataset_user_release_check(void * arg,dmu_tx_t * tx)422 dsl_dataset_user_release_check(void *arg, dmu_tx_t *tx)
423 {
424 dsl_dataset_user_release_arg_t *ddura;
425 dsl_holdfunc_t *holdfunc;
426 dsl_pool_t *dp;
427
428 if (!dmu_tx_is_syncing(tx))
429 return (0);
430
431 dp = dmu_tx_pool(tx);
432
433 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
434
435 ddura = arg;
436 holdfunc = ddura->ddura_holdfunc;
437
438 for (nvpair_t *pair = nvlist_next_nvpair(ddura->ddura_holds, NULL);
439 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
440 int error;
441 dsl_dataset_t *ds;
442 nvlist_t *holds;
443 const char *snapname = nvpair_name(pair);
444
445 error = nvpair_value_nvlist(pair, &holds);
446 if (error != 0)
447 error = (SET_ERROR(EINVAL));
448 else
449 error = holdfunc(dp, snapname, FTAG, &ds);
450 if (error == 0) {
451 error = dsl_dataset_user_release_check_one(ddura, ds,
452 holds, snapname);
453 dsl_dataset_rele(ds, FTAG);
454 }
455 if (error != 0) {
456 if (ddura->ddura_errlist != NULL) {
457 fnvlist_add_int32(ddura->ddura_errlist,
458 snapname, error);
459 }
460 /*
461 * Non-existent snapshots are put on the errlist,
462 * but don't cause an overall failure.
463 */
464 if (error != ENOENT)
465 return (error);
466 }
467 }
468
469 return (0);
470 }
471
472 static void
dsl_dataset_user_release_sync_one(dsl_dataset_t * ds,nvlist_t * holds,dmu_tx_t * tx)473 dsl_dataset_user_release_sync_one(dsl_dataset_t *ds, nvlist_t *holds,
474 dmu_tx_t *tx)
475 {
476 dsl_pool_t *dp = ds->ds_dir->dd_pool;
477 objset_t *mos = dp->dp_meta_objset;
478
479 for (nvpair_t *pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
480 pair = nvlist_next_nvpair(holds, pair)) {
481 int error;
482 const char *holdname = nvpair_name(pair);
483
484 /* Remove temporary hold if one exists. */
485 error = dsl_pool_user_release(dp, ds->ds_object, holdname, tx);
486 VERIFY(error == 0 || error == ENOENT);
487
488 VERIFY0(zap_remove(mos, dsl_dataset_phys(ds)->ds_userrefs_obj,
489 holdname, tx));
490 ds->ds_userrefs--;
491
492 spa_history_log_internal_ds(ds, "release", tx,
493 "tag=%s refs=%lld", holdname, (longlong_t)ds->ds_userrefs);
494 }
495 }
496
497 static void
dsl_dataset_user_release_sync(void * arg,dmu_tx_t * tx)498 dsl_dataset_user_release_sync(void *arg, dmu_tx_t *tx)
499 {
500 dsl_dataset_user_release_arg_t *ddura = arg;
501 dsl_holdfunc_t *holdfunc = ddura->ddura_holdfunc;
502 dsl_pool_t *dp = dmu_tx_pool(tx);
503
504 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
505
506 for (nvpair_t *pair = nvlist_next_nvpair(ddura->ddura_chkholds, NULL);
507 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_chkholds,
508 pair)) {
509 dsl_dataset_t *ds;
510 const char *name = nvpair_name(pair);
511
512 VERIFY0(holdfunc(dp, name, FTAG, &ds));
513
514 dsl_dataset_user_release_sync_one(ds,
515 fnvpair_value_nvlist(pair), tx);
516 if (nvlist_exists(ddura->ddura_todelete, name)) {
517 ASSERT(ds->ds_userrefs == 0 &&
518 dsl_dataset_phys(ds)->ds_num_children == 1 &&
519 DS_IS_DEFER_DESTROY(ds));
520 dsl_destroy_snapshot_sync_impl(ds, B_FALSE, tx);
521 }
522 dsl_dataset_rele(ds, FTAG);
523 }
524 }
525
526 /*
527 * The full semantics of this function are described in the comment above
528 * lzc_release().
529 *
530 * To summarize:
531 * Releases holds specified in the nvl holds.
532 *
533 * holds is nvl of snapname -> { holdname, ... }
534 * errlist will be filled in with snapname -> error
535 *
536 * If tmpdp is not NULL the names for holds should be the dsobj's of snapshots,
537 * otherwise they should be the names of shapshots.
538 *
539 * As a release may cause snapshots to be destroyed this trys to ensure they
540 * aren't mounted.
541 *
542 * The release of non-existent holds are skipped.
543 *
544 * At least one hold must have been released for the this function to succeed
545 * and return 0.
546 */
547 static int
dsl_dataset_user_release_impl(nvlist_t * holds,nvlist_t * errlist,dsl_pool_t * tmpdp)548 dsl_dataset_user_release_impl(nvlist_t *holds, nvlist_t *errlist,
549 dsl_pool_t *tmpdp)
550 {
551 dsl_dataset_user_release_arg_t ddura;
552 nvpair_t *pair;
553 char *pool;
554 int error;
555
556 pair = nvlist_next_nvpair(holds, NULL);
557 if (pair == NULL)
558 return (0);
559
560 /*
561 * The release may cause snapshots to be destroyed; make sure they
562 * are not mounted.
563 */
564 if (tmpdp != NULL) {
565 /* Temporary holds are specified by dsobj string. */
566 ddura.ddura_holdfunc = dsl_dataset_hold_obj_string;
567 pool = spa_name(tmpdp->dp_spa);
568 #ifdef _KERNEL
569 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
570 pair = nvlist_next_nvpair(holds, pair)) {
571 dsl_dataset_t *ds;
572
573 dsl_pool_config_enter(tmpdp, FTAG);
574 error = dsl_dataset_hold_obj_string(tmpdp,
575 nvpair_name(pair), FTAG, &ds);
576 if (error == 0) {
577 char name[ZFS_MAX_DATASET_NAME_LEN];
578 dsl_dataset_name(ds, name);
579 dsl_pool_config_exit(tmpdp, FTAG);
580 dsl_dataset_rele(ds, FTAG);
581 (void) zfs_unmount_snap(name);
582 } else {
583 dsl_pool_config_exit(tmpdp, FTAG);
584 }
585 }
586 #endif
587 } else {
588 /* Non-temporary holds are specified by name. */
589 ddura.ddura_holdfunc = dsl_dataset_hold;
590 pool = nvpair_name(pair);
591 #ifdef _KERNEL
592 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
593 pair = nvlist_next_nvpair(holds, pair)) {
594 (void) zfs_unmount_snap(nvpair_name(pair));
595 }
596 #endif
597 }
598
599 ddura.ddura_holds = holds;
600 ddura.ddura_errlist = errlist;
601 ddura.ddura_todelete = fnvlist_alloc();
602 ddura.ddura_chkholds = fnvlist_alloc();
603
604 error = dsl_sync_task(pool, dsl_dataset_user_release_check,
605 dsl_dataset_user_release_sync, &ddura, 0, ZFS_SPACE_CHECK_NONE);
606 fnvlist_free(ddura.ddura_todelete);
607 fnvlist_free(ddura.ddura_chkholds);
608
609 return (error);
610 }
611
612 /*
613 * holds is nvl of snapname -> { holdname, ... }
614 * errlist will be filled in with snapname -> error
615 */
616 int
dsl_dataset_user_release(nvlist_t * holds,nvlist_t * errlist)617 dsl_dataset_user_release(nvlist_t *holds, nvlist_t *errlist)
618 {
619 return (dsl_dataset_user_release_impl(holds, errlist, NULL));
620 }
621
622 /*
623 * holds is nvl of snapdsobj -> { holdname, ... }
624 */
625 void
dsl_dataset_user_release_tmp(struct dsl_pool * dp,nvlist_t * holds)626 dsl_dataset_user_release_tmp(struct dsl_pool *dp, nvlist_t *holds)
627 {
628 ASSERT(dp != NULL);
629 (void) dsl_dataset_user_release_impl(holds, NULL, dp);
630 }
631
632 int
dsl_dataset_get_holds(const char * dsname,nvlist_t * nvl)633 dsl_dataset_get_holds(const char *dsname, nvlist_t *nvl)
634 {
635 dsl_pool_t *dp;
636 dsl_dataset_t *ds;
637 int err;
638
639 err = dsl_pool_hold(dsname, FTAG, &dp);
640 if (err != 0)
641 return (err);
642 err = dsl_dataset_hold(dp, dsname, FTAG, &ds);
643 if (err != 0) {
644 dsl_pool_rele(dp, FTAG);
645 return (err);
646 }
647
648 if (dsl_dataset_phys(ds)->ds_userrefs_obj != 0) {
649 zap_attribute_t *za;
650 zap_cursor_t zc;
651
652 za = kmem_alloc(sizeof (zap_attribute_t), KM_SLEEP);
653 for (zap_cursor_init(&zc, ds->ds_dir->dd_pool->dp_meta_objset,
654 dsl_dataset_phys(ds)->ds_userrefs_obj);
655 zap_cursor_retrieve(&zc, za) == 0;
656 zap_cursor_advance(&zc)) {
657 fnvlist_add_uint64(nvl, za->za_name,
658 za->za_first_integer);
659 }
660 zap_cursor_fini(&zc);
661 kmem_free(za, sizeof (zap_attribute_t));
662 }
663 dsl_dataset_rele(ds, FTAG);
664 dsl_pool_rele(dp, FTAG);
665 return (0);
666 }
667