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 */
25
26 #include <sys/zfs_context.h>
27 #include <sys/dsl_userhold.h>
28 #include <sys/dsl_dataset.h>
29 #include <sys/dsl_destroy.h>
30 #include <sys/dsl_synctask.h>
31 #include <sys/dmu_tx.h>
32 #include <sys/zfs_onexit.h>
33 #include <sys/dsl_pool.h>
34 #include <sys/dsl_dir.h>
35 #include <sys/zfs_ioctl.h>
36 #include <sys/zap.h>
37
38 typedef struct dsl_dataset_user_hold_arg {
39 nvlist_t *dduha_holds;
40 nvlist_t *dduha_errlist;
41 minor_t dduha_minor;
42 } dsl_dataset_user_hold_arg_t;
43
44 /*
45 * If you add new checks here, you may need to add additional checks to the
46 * "temporary" case in snapshot_check() in dmu_objset.c.
47 */
48 int
49 dsl_dataset_user_hold_check_one(dsl_dataset_t *ds, const char *htag,
50 boolean_t temphold, dmu_tx_t *tx)
51 {
52 dsl_pool_t *dp = dmu_tx_pool(tx);
53 objset_t *mos = dp->dp_meta_objset;
54 int error = 0;
55
56 if (strlen(htag) > MAXNAMELEN)
57 return (E2BIG);
58 /* Tempholds have a more restricted length */
59 if (temphold && strlen(htag) + MAX_TAG_PREFIX_LEN >= MAXNAMELEN)
60 return (E2BIG);
61
62 /* tags must be unique (if ds already exists) */
63 if (ds != NULL) {
64 mutex_enter(&ds->ds_lock);
65 if (ds->ds_phys->ds_userrefs_obj != 0) {
66 uint64_t value;
67 error = zap_lookup(mos, ds->ds_phys->ds_userrefs_obj,
68 htag, 8, 1, &value);
69 if (error == 0)
70 error = SET_ERROR(EEXIST);
71 else if (error == ENOENT)
72 error = 0;
73 }
74 mutex_exit(&ds->ds_lock);
75 }
76
77 return (error);
78 }
79
80 static int
81 dsl_dataset_user_hold_check(void *arg, dmu_tx_t *tx)
82 {
83 dsl_dataset_user_hold_arg_t *dduha = arg;
84 dsl_pool_t *dp = dmu_tx_pool(tx);
85 nvpair_t *pair;
86 int rv = 0;
87
88 if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS)
89 return (SET_ERROR(ENOTSUP));
90
91 for (pair = nvlist_next_nvpair(dduha->dduha_holds, NULL); pair != NULL;
92 pair = nvlist_next_nvpair(dduha->dduha_holds, pair)) {
93 int error = 0;
94 dsl_dataset_t *ds;
95 char *htag;
96
97 /* must be a snapshot */
98 if (strchr(nvpair_name(pair), '@') == NULL)
99 error = SET_ERROR(EINVAL);
100
101 if (error == 0)
102 error = nvpair_value_string(pair, &htag);
103 if (error == 0) {
104 error = dsl_dataset_hold(dp,
105 nvpair_name(pair), FTAG, &ds);
106 }
107 if (error == 0) {
108 error = dsl_dataset_user_hold_check_one(ds, htag,
109 dduha->dduha_minor != 0, tx);
110 dsl_dataset_rele(ds, FTAG);
111 }
112
113 if (error != 0) {
114 rv = error;
115 fnvlist_add_int32(dduha->dduha_errlist,
116 nvpair_name(pair), error);
117 }
118 }
119 return (rv);
120 }
121
122 void
123 dsl_dataset_user_hold_sync_one(dsl_dataset_t *ds, const char *htag,
124 minor_t minor, uint64_t now, dmu_tx_t *tx)
125 {
126 dsl_pool_t *dp = ds->ds_dir->dd_pool;
127 objset_t *mos = dp->dp_meta_objset;
128 uint64_t zapobj;
129
130 mutex_enter(&ds->ds_lock);
131 if (ds->ds_phys->ds_userrefs_obj == 0) {
132 /*
133 * This is the first user hold for this dataset. Create
134 * the userrefs zap object.
135 */
136 dmu_buf_will_dirty(ds->ds_dbuf, tx);
137 zapobj = ds->ds_phys->ds_userrefs_obj =
138 zap_create(mos, DMU_OT_USERREFS, DMU_OT_NONE, 0, tx);
139 } else {
140 zapobj = ds->ds_phys->ds_userrefs_obj;
141 }
142 ds->ds_userrefs++;
143 mutex_exit(&ds->ds_lock);
144
145 VERIFY0(zap_add(mos, zapobj, htag, 8, 1, &now, tx));
146
147 if (minor != 0) {
148 VERIFY0(dsl_pool_user_hold(dp, ds->ds_object,
149 htag, now, tx));
150 dsl_register_onexit_hold_cleanup(ds, htag, minor);
151 }
152
153 spa_history_log_internal_ds(ds, "hold", tx,
154 "tag=%s temp=%d refs=%llu",
155 htag, minor != 0, ds->ds_userrefs);
156 }
157
158 static void
159 dsl_dataset_user_hold_sync(void *arg, dmu_tx_t *tx)
160 {
161 dsl_dataset_user_hold_arg_t *dduha = arg;
162 dsl_pool_t *dp = dmu_tx_pool(tx);
163 nvpair_t *pair;
164 uint64_t now = gethrestime_sec();
165
166 for (pair = nvlist_next_nvpair(dduha->dduha_holds, NULL); pair != NULL;
167 pair = nvlist_next_nvpair(dduha->dduha_holds, pair)) {
168 dsl_dataset_t *ds;
169 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
170 dsl_dataset_user_hold_sync_one(ds, fnvpair_value_string(pair),
171 dduha->dduha_minor, now, tx);
172 dsl_dataset_rele(ds, FTAG);
173 }
174 }
175
176 /*
177 * holds is nvl of snapname -> holdname
178 * errlist will be filled in with snapname -> error
179 * if cleanup_minor is not 0, the holds will be temporary, cleaned up
180 * when the process exits.
181 *
182 * if any fails, all will fail.
183 */
184 int
185 dsl_dataset_user_hold(nvlist_t *holds, minor_t cleanup_minor, nvlist_t *errlist)
186 {
187 dsl_dataset_user_hold_arg_t dduha;
188 nvpair_t *pair;
189
190 pair = nvlist_next_nvpair(holds, NULL);
191 if (pair == NULL)
192 return (0);
193
194 dduha.dduha_holds = holds;
195 dduha.dduha_errlist = errlist;
196 dduha.dduha_minor = cleanup_minor;
197
198 return (dsl_sync_task(nvpair_name(pair), dsl_dataset_user_hold_check,
199 dsl_dataset_user_hold_sync, &dduha, fnvlist_num_pairs(holds)));
200 }
201
202 typedef struct dsl_dataset_user_release_arg {
203 nvlist_t *ddura_holds;
204 nvlist_t *ddura_todelete;
205 nvlist_t *ddura_errlist;
206 } dsl_dataset_user_release_arg_t;
207
208 static int
209 dsl_dataset_user_release_check_one(dsl_dataset_t *ds,
210 nvlist_t *holds, boolean_t *todelete)
211 {
212 uint64_t zapobj;
213 nvpair_t *pair;
214 objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
215 int error;
216 int numholds = 0;
217
218 *todelete = B_FALSE;
219
220 if (!dsl_dataset_is_snapshot(ds))
221 return (SET_ERROR(EINVAL));
222
223 zapobj = ds->ds_phys->ds_userrefs_obj;
224 if (zapobj == 0)
225 return (SET_ERROR(ESRCH));
226
227 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
228 pair = nvlist_next_nvpair(holds, pair)) {
229 /* Make sure the hold exists */
230 uint64_t tmp;
231 error = zap_lookup(mos, zapobj, nvpair_name(pair), 8, 1, &tmp);
232 if (error == ENOENT)
233 error = SET_ERROR(ESRCH);
234 if (error != 0)
235 return (error);
236 numholds++;
237 }
238
239 if (DS_IS_DEFER_DESTROY(ds) && ds->ds_phys->ds_num_children == 1 &&
240 ds->ds_userrefs == numholds) {
241 /* we need to destroy the snapshot as well */
242
243 if (dsl_dataset_long_held(ds))
244 return (SET_ERROR(EBUSY));
245 *todelete = B_TRUE;
246 }
247 return (0);
248 }
249
250 static int
251 dsl_dataset_user_release_check(void *arg, dmu_tx_t *tx)
252 {
253 dsl_dataset_user_release_arg_t *ddura = arg;
254 dsl_pool_t *dp = dmu_tx_pool(tx);
255 nvpair_t *pair;
256 int rv = 0;
257
258 if (!dmu_tx_is_syncing(tx))
259 return (0);
260
261 for (pair = nvlist_next_nvpair(ddura->ddura_holds, NULL); pair != NULL;
262 pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
263 const char *name = nvpair_name(pair);
264 int error;
265 dsl_dataset_t *ds;
266 nvlist_t *holds;
267
268 error = nvpair_value_nvlist(pair, &holds);
269 if (error != 0)
270 return (SET_ERROR(EINVAL));
271
272 error = dsl_dataset_hold(dp, name, FTAG, &ds);
273 if (error == 0) {
274 boolean_t deleteme;
275 error = dsl_dataset_user_release_check_one(ds,
276 holds, &deleteme);
277 if (error == 0 && deleteme) {
278 fnvlist_add_boolean(ddura->ddura_todelete,
279 name);
280 }
281 dsl_dataset_rele(ds, FTAG);
282 }
283 if (error != 0) {
284 if (ddura->ddura_errlist != NULL) {
285 fnvlist_add_int32(ddura->ddura_errlist,
286 name, error);
287 }
288 rv = error;
289 }
290 }
291 return (rv);
292 }
293
294 static void
295 dsl_dataset_user_release_sync_one(dsl_dataset_t *ds, nvlist_t *holds,
296 dmu_tx_t *tx)
297 {
298 dsl_pool_t *dp = ds->ds_dir->dd_pool;
299 objset_t *mos = dp->dp_meta_objset;
300 uint64_t zapobj;
301 int error;
302 nvpair_t *pair;
303
304 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
305 pair = nvlist_next_nvpair(holds, pair)) {
306 ds->ds_userrefs--;
307 error = dsl_pool_user_release(dp, ds->ds_object,
308 nvpair_name(pair), tx);
309 VERIFY(error == 0 || error == ENOENT);
310 zapobj = ds->ds_phys->ds_userrefs_obj;
311 VERIFY0(zap_remove(mos, zapobj, nvpair_name(pair), tx));
312
313 spa_history_log_internal_ds(ds, "release", tx,
314 "tag=%s refs=%lld", nvpair_name(pair),
315 (longlong_t)ds->ds_userrefs);
316 }
317 }
318
319 static void
320 dsl_dataset_user_release_sync(void *arg, dmu_tx_t *tx)
321 {
322 dsl_dataset_user_release_arg_t *ddura = arg;
323 dsl_pool_t *dp = dmu_tx_pool(tx);
324 nvpair_t *pair;
325
326 for (pair = nvlist_next_nvpair(ddura->ddura_holds, NULL); pair != NULL;
327 pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
328 dsl_dataset_t *ds;
329
330 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
331 dsl_dataset_user_release_sync_one(ds,
332 fnvpair_value_nvlist(pair), tx);
333 if (nvlist_exists(ddura->ddura_todelete,
334 nvpair_name(pair))) {
335 ASSERT(ds->ds_userrefs == 0 &&
336 ds->ds_phys->ds_num_children == 1 &&
337 DS_IS_DEFER_DESTROY(ds));
338 dsl_destroy_snapshot_sync_impl(ds, B_FALSE, tx);
339 }
340 dsl_dataset_rele(ds, FTAG);
341 }
342 }
343
344 /*
345 * holds is nvl of snapname -> { holdname, ... }
346 * errlist will be filled in with snapname -> error
347 *
348 * if any fails, all will fail.
349 */
350 int
351 dsl_dataset_user_release(nvlist_t *holds, nvlist_t *errlist)
352 {
353 dsl_dataset_user_release_arg_t ddura;
354 nvpair_t *pair;
355 int error;
356
357 pair = nvlist_next_nvpair(holds, NULL);
358 if (pair == NULL)
359 return (0);
360
361 ddura.ddura_holds = holds;
362 ddura.ddura_errlist = errlist;
363 ddura.ddura_todelete = fnvlist_alloc();
364
365 error = dsl_sync_task(nvpair_name(pair), dsl_dataset_user_release_check,
366 dsl_dataset_user_release_sync, &ddura, fnvlist_num_pairs(holds));
367 fnvlist_free(ddura.ddura_todelete);
368 return (error);
369 }
370
371 typedef struct dsl_dataset_user_release_tmp_arg {
372 uint64_t ddurta_dsobj;
373 nvlist_t *ddurta_holds;
374 boolean_t ddurta_deleteme;
375 } dsl_dataset_user_release_tmp_arg_t;
376
377 static int
378 dsl_dataset_user_release_tmp_check(void *arg, dmu_tx_t *tx)
379 {
380 dsl_dataset_user_release_tmp_arg_t *ddurta = arg;
381 dsl_pool_t *dp = dmu_tx_pool(tx);
382 dsl_dataset_t *ds;
383 int error;
384
385 if (!dmu_tx_is_syncing(tx))
386 return (0);
387
388 error = dsl_dataset_hold_obj(dp, ddurta->ddurta_dsobj, FTAG, &ds);
389 if (error)
390 return (error);
391
392 error = dsl_dataset_user_release_check_one(ds,
393 ddurta->ddurta_holds, &ddurta->ddurta_deleteme);
394 dsl_dataset_rele(ds, FTAG);
395 return (error);
396 }
397
398 static void
399 dsl_dataset_user_release_tmp_sync(void *arg, dmu_tx_t *tx)
400 {
401 dsl_dataset_user_release_tmp_arg_t *ddurta = arg;
402 dsl_pool_t *dp = dmu_tx_pool(tx);
403 dsl_dataset_t *ds;
404
405 VERIFY0(dsl_dataset_hold_obj(dp, ddurta->ddurta_dsobj, FTAG, &ds));
406 dsl_dataset_user_release_sync_one(ds, ddurta->ddurta_holds, tx);
407 if (ddurta->ddurta_deleteme) {
408 ASSERT(ds->ds_userrefs == 0 &&
409 ds->ds_phys->ds_num_children == 1 &&
410 DS_IS_DEFER_DESTROY(ds));
411 dsl_destroy_snapshot_sync_impl(ds, B_FALSE, tx);
412 }
413 dsl_dataset_rele(ds, FTAG);
414 }
415
416 /*
417 * Called at spa_load time to release a stale temporary user hold.
418 * Also called by the onexit code.
419 */
420 void
421 dsl_dataset_user_release_tmp(dsl_pool_t *dp, uint64_t dsobj, const char *htag)
422 {
423 dsl_dataset_user_release_tmp_arg_t ddurta;
424 dsl_dataset_t *ds;
425 int error;
426
427 #ifdef _KERNEL
428 /* Make sure it is not mounted. */
429 dsl_pool_config_enter(dp, FTAG);
430 error = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
431 if (error == 0) {
432 char name[MAXNAMELEN];
433 dsl_dataset_name(ds, name);
434 dsl_dataset_rele(ds, FTAG);
435 dsl_pool_config_exit(dp, FTAG);
436 zfs_unmount_snap(name);
437 } else {
438 dsl_pool_config_exit(dp, FTAG);
439 }
440 #endif
441
442 ddurta.ddurta_dsobj = dsobj;
443 ddurta.ddurta_holds = fnvlist_alloc();
444 fnvlist_add_boolean(ddurta.ddurta_holds, htag);
445
446 (void) dsl_sync_task(spa_name(dp->dp_spa),
447 dsl_dataset_user_release_tmp_check,
448 dsl_dataset_user_release_tmp_sync, &ddurta, 1);
449 fnvlist_free(ddurta.ddurta_holds);
450 }
451
452 typedef struct zfs_hold_cleanup_arg {
453 char zhca_spaname[MAXNAMELEN];
454 uint64_t zhca_spa_load_guid;
455 uint64_t zhca_dsobj;
456 char zhca_htag[MAXNAMELEN];
457 } zfs_hold_cleanup_arg_t;
458
459 static void
460 dsl_dataset_user_release_onexit(void *arg)
461 {
462 zfs_hold_cleanup_arg_t *ca = arg;
463 spa_t *spa;
464 int error;
465
466 error = spa_open(ca->zhca_spaname, &spa, FTAG);
467 if (error != 0) {
468 zfs_dbgmsg("couldn't release hold on pool=%s ds=%llu tag=%s "
469 "because pool is no longer loaded",
470 ca->zhca_spaname, ca->zhca_dsobj, ca->zhca_htag);
471 return;
472 }
473 if (spa_load_guid(spa) != ca->zhca_spa_load_guid) {
474 zfs_dbgmsg("couldn't release hold on pool=%s ds=%llu tag=%s "
475 "because pool is no longer loaded (guid doesn't match)",
476 ca->zhca_spaname, ca->zhca_dsobj, ca->zhca_htag);
477 spa_close(spa, FTAG);
478 return;
479 }
480
481 dsl_dataset_user_release_tmp(spa_get_dsl(spa),
482 ca->zhca_dsobj, ca->zhca_htag);
483 kmem_free(ca, sizeof (zfs_hold_cleanup_arg_t));
484 spa_close(spa, FTAG);
485 }
486
487 void
488 dsl_register_onexit_hold_cleanup(dsl_dataset_t *ds, const char *htag,
489 minor_t minor)
490 {
491 zfs_hold_cleanup_arg_t *ca = kmem_alloc(sizeof (*ca), KM_SLEEP);
492 spa_t *spa = dsl_dataset_get_spa(ds);
493 (void) strlcpy(ca->zhca_spaname, spa_name(spa),
494 sizeof (ca->zhca_spaname));
495 ca->zhca_spa_load_guid = spa_load_guid(spa);
496 ca->zhca_dsobj = ds->ds_object;
497 (void) strlcpy(ca->zhca_htag, htag, sizeof (ca->zhca_htag));
498 VERIFY0(zfs_onexit_add_cb(minor,
499 dsl_dataset_user_release_onexit, ca, NULL));
500 }
501
502 int
503 dsl_dataset_get_holds(const char *dsname, nvlist_t *nvl)
504 {
505 dsl_pool_t *dp;
506 dsl_dataset_t *ds;
507 int err;
508
509 err = dsl_pool_hold(dsname, FTAG, &dp);
510 if (err != 0)
511 return (err);
512 err = dsl_dataset_hold(dp, dsname, FTAG, &ds);
513 if (err != 0) {
514 dsl_pool_rele(dp, FTAG);
515 return (err);
516 }
517
518 if (ds->ds_phys->ds_userrefs_obj != 0) {
519 zap_attribute_t *za;
|
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_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
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 && ds->ds_phys->ds_userrefs_obj != 0) {
68 uint64_t value;
69
70 error = zap_lookup(mos, ds->ds_phys->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
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 ENOENT if no holds would be created. */
130 if (nvlist_empty(dduha->dduha_chkholds))
131 return (SET_ERROR(ENOENT));
132
133 return (0);
134 }
135
136
137 static void
138 dsl_dataset_user_hold_sync_one_impl(nvlist_t *tmpholds, dsl_dataset_t *ds,
139 const char *htag, minor_t minor, uint64_t now, dmu_tx_t *tx)
140 {
141 dsl_pool_t *dp = ds->ds_dir->dd_pool;
142 objset_t *mos = dp->dp_meta_objset;
143 uint64_t zapobj;
144
145 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
146
147 if (ds->ds_phys->ds_userrefs_obj == 0) {
148 /*
149 * This is the first user hold for this dataset. Create
150 * the userrefs zap object.
151 */
152 dmu_buf_will_dirty(ds->ds_dbuf, tx);
153 zapobj = ds->ds_phys->ds_userrefs_obj =
154 zap_create(mos, DMU_OT_USERREFS, DMU_OT_NONE, 0, tx);
155 } else {
156 zapobj = ds->ds_phys->ds_userrefs_obj;
157 }
158 ds->ds_userrefs++;
159
160 VERIFY0(zap_add(mos, zapobj, htag, 8, 1, &now, tx));
161
162 if (minor != 0) {
163 char name[MAXNAMELEN];
164 nvlist_t *tags;
165
166 VERIFY0(dsl_pool_user_hold(dp, ds->ds_object,
167 htag, now, tx));
168 (void) snprintf(name, sizeof (name), "%llx",
169 (u_longlong_t)ds->ds_object);
170
171 if (nvlist_lookup_nvlist(tmpholds, name, &tags) != 0) {
172 tags = fnvlist_alloc();
173 fnvlist_add_boolean(tags, htag);
174 fnvlist_add_nvlist(tmpholds, name, tags);
175 fnvlist_free(tags);
176 } else {
177 fnvlist_add_boolean(tags, htag);
178 }
179 }
180
181 spa_history_log_internal_ds(ds, "hold", tx,
182 "tag=%s temp=%d refs=%llu",
183 htag, minor != 0, ds->ds_userrefs);
184 }
185
186 typedef struct zfs_hold_cleanup_arg {
187 char zhca_spaname[MAXNAMELEN];
188 uint64_t zhca_spa_load_guid;
189 nvlist_t *zhca_holds;
190 } zfs_hold_cleanup_arg_t;
191
192 static void
193 dsl_dataset_user_release_onexit(void *arg)
194 {
195 zfs_hold_cleanup_arg_t *ca = arg;
196 spa_t *spa;
197 int error;
198
199 error = spa_open(ca->zhca_spaname, &spa, FTAG);
200 if (error != 0) {
201 zfs_dbgmsg("couldn't release holds on pool=%s "
202 "because pool is no longer loaded",
203 ca->zhca_spaname);
204 return;
205 }
206 if (spa_load_guid(spa) != ca->zhca_spa_load_guid) {
207 zfs_dbgmsg("couldn't release holds on pool=%s "
208 "because pool is no longer loaded (guid doesn't match)",
209 ca->zhca_spaname);
210 spa_close(spa, FTAG);
211 return;
212 }
213
214 (void) dsl_dataset_user_release_tmp(spa_get_dsl(spa), ca->zhca_holds);
215 fnvlist_free(ca->zhca_holds);
216 kmem_free(ca, sizeof (zfs_hold_cleanup_arg_t));
217 spa_close(spa, FTAG);
218 }
219
220 static void
221 dsl_onexit_hold_cleanup(spa_t *spa, nvlist_t *holds, minor_t minor)
222 {
223 zfs_hold_cleanup_arg_t *ca;
224
225 if (minor == 0 || nvlist_empty(holds)) {
226 fnvlist_free(holds);
227 return;
228 }
229
230 ASSERT(spa != NULL);
231 ca = kmem_alloc(sizeof (*ca), KM_SLEEP);
232
233 (void) strlcpy(ca->zhca_spaname, spa_name(spa),
234 sizeof (ca->zhca_spaname));
235 ca->zhca_spa_load_guid = spa_load_guid(spa);
236 ca->zhca_holds = holds;
237 VERIFY0(zfs_onexit_add_cb(minor,
238 dsl_dataset_user_release_onexit, ca, NULL));
239 }
240
241 void
242 dsl_dataset_user_hold_sync_one(dsl_dataset_t *ds, const char *htag,
243 minor_t minor, uint64_t now, dmu_tx_t *tx)
244 {
245 nvlist_t *tmpholds;
246
247 if (minor != 0)
248 tmpholds = fnvlist_alloc();
249 else
250 tmpholds = NULL;
251 dsl_dataset_user_hold_sync_one_impl(tmpholds, ds, htag, minor, now, tx);
252 dsl_onexit_hold_cleanup(dsl_dataset_get_spa(ds), tmpholds, minor);
253 }
254
255 static void
256 dsl_dataset_user_hold_sync(void *arg, dmu_tx_t *tx)
257 {
258 dsl_dataset_user_hold_arg_t *dduha = arg;
259 dsl_pool_t *dp = dmu_tx_pool(tx);
260 nvlist_t *tmpholds;
261 uint64_t now = gethrestime_sec();
262
263 if (dduha->dduha_minor != 0)
264 tmpholds = fnvlist_alloc();
265 else
266 tmpholds = NULL;
267 for (nvpair_t *pair = nvlist_next_nvpair(dduha->dduha_chkholds, NULL);
268 pair != NULL;
269 pair = nvlist_next_nvpair(dduha->dduha_chkholds, pair)) {
270 dsl_dataset_t *ds;
271
272 VERIFY0(dsl_dataset_hold(dp, nvpair_name(pair), FTAG, &ds));
273 dsl_dataset_user_hold_sync_one_impl(tmpholds, ds,
274 fnvpair_value_string(pair), dduha->dduha_minor, now, tx);
275 dsl_dataset_rele(ds, FTAG);
276 }
277 dsl_onexit_hold_cleanup(dp->dp_spa, tmpholds, dduha->dduha_minor);
278 }
279
280 /*
281 * The full semantics of this function are described in the comment above
282 * lzc_hold().
283 *
284 * To summarize:
285 * holds is nvl of snapname -> holdname
286 * errlist will be filled in with snapname -> error
287 *
288 * The snaphosts must all be in the same pool.
289 *
290 * Holds for snapshots that don't exist will be skipped.
291 *
292 * If none of the snapshots for requested holds exist then ENOENT will be
293 * returned.
294 *
295 * If cleanup_minor is not 0, the holds will be temporary, which will be cleaned
296 * up when the process exits.
297 *
298 * On success all the holds, for snapshots that existed, will be created and 0
299 * will be returned.
300 *
301 * On failure no holds will be created, the errlist will be filled in,
302 * and an errno will returned.
303 *
304 * In all cases the errlist will contain entries for holds where the snapshot
305 * didn't exist.
306 */
307 int
308 dsl_dataset_user_hold(nvlist_t *holds, minor_t cleanup_minor, nvlist_t *errlist)
309 {
310 dsl_dataset_user_hold_arg_t dduha;
311 nvpair_t *pair;
312 int ret;
313
314 pair = nvlist_next_nvpair(holds, NULL);
315 if (pair == NULL)
316 return (0);
317
318 dduha.dduha_holds = holds;
319 dduha.dduha_chkholds = fnvlist_alloc();
320 dduha.dduha_errlist = errlist;
321 dduha.dduha_minor = cleanup_minor;
322
323 ret = dsl_sync_task(nvpair_name(pair), dsl_dataset_user_hold_check,
324 dsl_dataset_user_hold_sync, &dduha, fnvlist_num_pairs(holds));
325 fnvlist_free(dduha.dduha_chkholds);
326
327 return (ret);
328 }
329
330 typedef int (dsl_holdfunc_t)(dsl_pool_t *dp, const char *name, void *tag,
331 dsl_dataset_t **dsp);
332
333 typedef struct dsl_dataset_user_release_arg {
334 dsl_holdfunc_t *ddura_holdfunc;
335 nvlist_t *ddura_holds;
336 nvlist_t *ddura_todelete;
337 nvlist_t *ddura_errlist;
338 nvlist_t *ddura_chkholds;
339 } dsl_dataset_user_release_arg_t;
340
341 /* Place a dataset hold on the snapshot identified by passed dsobj string */
342 static int
343 dsl_dataset_hold_obj_string(dsl_pool_t *dp, const char *dsobj, void *tag,
344 dsl_dataset_t **dsp)
345 {
346 return (dsl_dataset_hold_obj(dp, strtonum(dsobj, NULL), tag, dsp));
347 }
348
349 static int
350 dsl_dataset_user_release_check_one(dsl_dataset_user_release_arg_t *ddura,
351 dsl_dataset_t *ds, nvlist_t *holds, const char *snapname)
352 {
353 uint64_t zapobj;
354 nvlist_t *holds_found;
355 objset_t *mos;
356 int numholds;
357
358 if (!dsl_dataset_is_snapshot(ds))
359 return (SET_ERROR(EINVAL));
360
361 if (nvlist_empty(holds))
362 return (0);
363
364 numholds = 0;
365 mos = ds->ds_dir->dd_pool->dp_meta_objset;
366 zapobj = ds->ds_phys->ds_userrefs_obj;
367 holds_found = fnvlist_alloc();
368
369 for (nvpair_t *pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
370 pair = nvlist_next_nvpair(holds, pair)) {
371 uint64_t tmp;
372 int error;
373 const char *holdname = nvpair_name(pair);
374
375 if (zapobj != 0)
376 error = zap_lookup(mos, zapobj, holdname, 8, 1, &tmp);
377 else
378 error = SET_ERROR(ENOENT);
379
380 /*
381 * Non-existent holds are put on the errlist, but don't
382 * cause an overall failure.
383 */
384 if (error == ENOENT) {
385 if (ddura->ddura_errlist != NULL) {
386 char *errtag = kmem_asprintf("%s#%s",
387 snapname, holdname);
388 fnvlist_add_int32(ddura->ddura_errlist, errtag,
389 ENOENT);
390 strfree(errtag);
391 }
392 continue;
393 }
394
395 if (error != 0) {
396 fnvlist_free(holds_found);
397 return (error);
398 }
399
400 fnvlist_add_boolean(holds_found, holdname);
401 numholds++;
402 }
403
404 if (DS_IS_DEFER_DESTROY(ds) && ds->ds_phys->ds_num_children == 1 &&
405 ds->ds_userrefs == numholds) {
406 /* we need to destroy the snapshot as well */
407 if (dsl_dataset_long_held(ds)) {
408 fnvlist_free(holds_found);
409 return (SET_ERROR(EBUSY));
410 }
411 fnvlist_add_boolean(ddura->ddura_todelete, snapname);
412 }
413
414 if (numholds != 0) {
415 fnvlist_add_nvlist(ddura->ddura_chkholds, snapname,
416 holds_found);
417 }
418 fnvlist_free(holds_found);
419
420 return (0);
421 }
422
423 static int
424 dsl_dataset_user_release_check(void *arg, dmu_tx_t *tx)
425 {
426 dsl_dataset_user_release_arg_t *ddura;
427 dsl_holdfunc_t *holdfunc;
428 dsl_pool_t *dp;
429
430 if (!dmu_tx_is_syncing(tx))
431 return (0);
432
433 dp = dmu_tx_pool(tx);
434
435 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
436
437 ddura = arg;
438 holdfunc = ddura->ddura_holdfunc;
439
440 for (nvpair_t *pair = nvlist_next_nvpair(ddura->ddura_holds, NULL);
441 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
442 int error;
443 dsl_dataset_t *ds;
444 nvlist_t *holds;
445 const char *snapname = nvpair_name(pair);
446
447 error = nvpair_value_nvlist(pair, &holds);
448 if (error != 0)
449 error = (SET_ERROR(EINVAL));
450 else
451 error = holdfunc(dp, snapname, FTAG, &ds);
452 if (error == 0) {
453 error = dsl_dataset_user_release_check_one(ddura, ds,
454 holds, snapname);
455 dsl_dataset_rele(ds, FTAG);
456 }
457 if (error != 0) {
458 if (ddura->ddura_errlist != NULL) {
459 fnvlist_add_int32(ddura->ddura_errlist,
460 snapname, error);
461 }
462 /*
463 * Non-existent snapshots are put on the errlist,
464 * but don't cause an overall failure.
465 */
466 if (error != ENOENT)
467 return (error);
468 }
469 }
470
471 /* Return ENOENT if none of the holds existed. */
472 if (nvlist_empty(ddura->ddura_chkholds))
473 return (SET_ERROR(ENOENT));
474
475 return (0);
476 }
477
478 static void
479 dsl_dataset_user_release_sync_one(dsl_dataset_t *ds, nvlist_t *holds,
480 dmu_tx_t *tx)
481 {
482 dsl_pool_t *dp = ds->ds_dir->dd_pool;
483 objset_t *mos = dp->dp_meta_objset;
484
485 for (nvpair_t *pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
486 pair = nvlist_next_nvpair(holds, pair)) {
487 int error;
488 const char *holdname = nvpair_name(pair);
489
490 /* Remove temporary hold if one exists. */
491 error = dsl_pool_user_release(dp, ds->ds_object, holdname, tx);
492 VERIFY(error == 0 || error == ENOENT);
493
494 VERIFY0(zap_remove(mos, ds->ds_phys->ds_userrefs_obj, holdname,
495 tx));
496 ds->ds_userrefs--;
497
498 spa_history_log_internal_ds(ds, "release", tx,
499 "tag=%s refs=%lld", holdname, (longlong_t)ds->ds_userrefs);
500 }
501 }
502
503 static void
504 dsl_dataset_user_release_sync(void *arg, dmu_tx_t *tx)
505 {
506 dsl_dataset_user_release_arg_t *ddura = arg;
507 dsl_holdfunc_t *holdfunc = ddura->ddura_holdfunc;
508 dsl_pool_t *dp = dmu_tx_pool(tx);
509
510 ASSERT(RRW_WRITE_HELD(&dp->dp_config_rwlock));
511
512 for (nvpair_t *pair = nvlist_next_nvpair(ddura->ddura_chkholds, NULL);
513 pair != NULL; pair = nvlist_next_nvpair(ddura->ddura_chkholds,
514 pair)) {
515 dsl_dataset_t *ds;
516 const char *name = nvpair_name(pair);
517
518 VERIFY0(holdfunc(dp, name, FTAG, &ds));
519
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 ds->ds_phys->ds_num_children == 1 &&
525 DS_IS_DEFER_DESTROY(ds));
526 dsl_destroy_snapshot_sync_impl(ds, B_FALSE, tx);
527 }
528 dsl_dataset_rele(ds, FTAG);
529 }
530 }
531
532 /*
533 * The full semantics of this function are described in the comment above
534 * lzc_release().
535 *
536 * To summarize:
537 * Releases holds specified in the nvl holds.
538 *
539 * holds is nvl of snapname -> { holdname, ... }
540 * errlist will be filled in with snapname -> error
541 *
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.
544 *
545 * As a release may cause snapshots to be destroyed this trys to ensure they
546 * aren't mounted.
547 *
548 * The release of non-existent holds are skipped.
549 *
550 * At least one hold must have been released for the this function to succeed
551 * and return 0.
552 */
553 static int
554 dsl_dataset_user_release_impl(nvlist_t *holds, nvlist_t *errlist,
555 dsl_pool_t *tmpdp)
556 {
557 dsl_dataset_user_release_arg_t ddura;
558 nvpair_t *pair;
559 char *pool;
560 int error;
561
562 pair = nvlist_next_nvpair(holds, NULL);
563 if (pair == NULL)
564 return (0);
565
566 /*
567 * The release may cause snapshots to be destroyed; make sure they
568 * are not mounted.
569 */
570 if (tmpdp != NULL) {
571 /* Temporary holds are specified by dsobj string. */
572 ddura.ddura_holdfunc = dsl_dataset_hold_obj_string;
573 pool = spa_name(tmpdp->dp_spa);
574 #ifdef _KERNEL
575 dsl_pool_config_enter(tmpdp, FTAG);
576 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
577 pair = nvlist_next_nvpair(holds, pair)) {
578 dsl_dataset_t *ds;
579
580 error = dsl_dataset_hold_obj_string(tmpdp,
581 nvpair_name(pair), FTAG, &ds);
582 if (error == 0) {
583 char name[MAXNAMELEN];
584 dsl_dataset_name(ds, name);
585 dsl_dataset_rele(ds, FTAG);
586 zfs_unmount_snap(name);
587 }
588 }
589 dsl_pool_config_exit(tmpdp, FTAG);
590 #endif
591 } else {
592 /* Non-temporary holds are specified by name. */
593 ddura.ddura_holdfunc = dsl_dataset_hold;
594 pool = nvpair_name(pair);
595 #ifdef _KERNEL
596 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
597 pair = nvlist_next_nvpair(holds, pair)) {
598 zfs_unmount_snap(nvpair_name(pair));
599 }
600 #endif
601 }
602
603 ddura.ddura_holds = holds;
604 ddura.ddura_errlist = errlist;
605 ddura.ddura_todelete = fnvlist_alloc();
606 ddura.ddura_chkholds = fnvlist_alloc();
607
608 error = dsl_sync_task(pool, dsl_dataset_user_release_check,
609 dsl_dataset_user_release_sync, &ddura,
610 fnvlist_num_pairs(holds));
611 fnvlist_free(ddura.ddura_todelete);
612 fnvlist_free(ddura.ddura_chkholds);
613
614 return (error);
615 }
616
617 /*
618 * holds is nvl of snapname -> { holdname, ... }
619 * errlist will be filled in with snapname -> error
620 */
621 int
622 dsl_dataset_user_release(nvlist_t *holds, nvlist_t *errlist)
623 {
624 return (dsl_dataset_user_release_impl(holds, errlist, NULL));
625 }
626
627 /*
628 * holds is nvl of snapdsobj -> { holdname, ... }
629 */
630 void
631 dsl_dataset_user_release_tmp(struct dsl_pool *dp, nvlist_t *holds)
632 {
633 ASSERT(dp != NULL);
634 (void) dsl_dataset_user_release_impl(holds, NULL, dp);
635 }
636
637 int
638 dsl_dataset_get_holds(const char *dsname, nvlist_t *nvl)
639 {
640 dsl_pool_t *dp;
641 dsl_dataset_t *ds;
642 int err;
643
644 err = dsl_pool_hold(dsname, FTAG, &dp);
645 if (err != 0)
646 return (err);
647 err = dsl_dataset_hold(dp, dsname, FTAG, &ds);
648 if (err != 0) {
649 dsl_pool_rele(dp, FTAG);
650 return (err);
651 }
652
653 if (ds->ds_phys->ds_userrefs_obj != 0) {
654 zap_attribute_t *za;
|