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
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;
|
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 spa_t *dduha_spa;
40 nvlist_t *dduha_holds;
41 nvlist_t *dduha_tmpholds;
42 nvlist_t *dduha_errlist;
43 minor_t dduha_minor;
44 boolean_t dduha_holds_created;
45 } dsl_dataset_user_hold_arg_t;
46
47 /*
48 * If you add new checks here, you may need to add additional checks to the
49 * "temporary" case in snapshot_check() in dmu_objset.c.
50 */
51 int
52 dsl_dataset_user_hold_check_one(dsl_dataset_t *ds, const char *htag,
53 boolean_t temphold, dmu_tx_t *tx)
54 {
55 dsl_pool_t *dp = dmu_tx_pool(tx);
56 objset_t *mos = dp->dp_meta_objset;
57 int error = 0;
58
59 if (strlen(htag) > MAXNAMELEN)
60 return (E2BIG);
61 /* Tempholds have a more restricted length */
62 if (temphold && strlen(htag) + MAX_TAG_PREFIX_LEN >= MAXNAMELEN)
63 return (E2BIG);
64
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 mutex_exit(&ds->ds_lock);
78 }
79
80 return (error);
81 }
82
83 static int
84 dsl_dataset_user_hold_check(void *arg, dmu_tx_t *tx)
85 {
86 dsl_dataset_user_hold_arg_t *dduha = arg;
87 dsl_pool_t *dp = dmu_tx_pool(tx);
88 nvpair_t *pair;
89 int rv = 0;
90 boolean_t holds_possible;
91
92 if (spa_version(dp->dp_spa) < SPA_VERSION_USERREFS)
93 return (SET_ERROR(ENOTSUP));
94
95 holds_possible = B_FALSE;
96
97 for (pair = nvlist_next_nvpair(dduha->dduha_holds, NULL); pair != NULL;
98 pair = nvlist_next_nvpair(dduha->dduha_holds, pair)) {
99 int error = 0;
100 dsl_dataset_t *ds;
101 char *htag;
102
103 /* must be a snapshot */
104 if (strchr(nvpair_name(pair), '@') == NULL)
105 error = SET_ERROR(EINVAL);
106
107 if (error == 0)
108 error = nvpair_value_string(pair, &htag);
109 if (error == 0) {
110 error = dsl_dataset_hold(dp,
111 nvpair_name(pair), FTAG, &ds);
112
113 if (error == ENOENT) {
114 /*
115 * We register ENOENT errors so they can be
116 * correctly reported if needed, such as when
117 * all holds fail.
118 */
119 if (dduha->dduha_errlist != NULL) {
120 fnvlist_add_int32(dduha->dduha_errlist,
121 nvpair_name(pair), error);
122 }
123 continue;
124 }
125 }
126 if (error == 0) {
127 error = dsl_dataset_user_hold_check_one(ds, htag,
128 dduha->dduha_minor != 0, tx);
129 dsl_dataset_rele(ds, FTAG);
130 }
131
132 if (error != 0) {
133 if (dduha->dduha_errlist != NULL) {
134 fnvlist_add_int32(dduha->dduha_errlist,
135 nvpair_name(pair), error);
136 }
137 rv = error;
138 } else {
139 holds_possible = B_TRUE;
140 }
141 }
142
143 /*
144 * Check that at least one hold will possibly be created,
145 * otherwise fail.
146 */
147 if (rv == 0 && !holds_possible)
148 rv = ENOENT;
149
150 return (rv);
151 }
152
153
154 static void
155 dsl_dataset_user_hold_sync_one_impl(dsl_dataset_user_hold_arg_t *dduha,
156 dsl_dataset_t *ds, const char *htag, minor_t minor, uint64_t now,
157 dmu_tx_t *tx)
158 {
159 dsl_pool_t *dp = ds->ds_dir->dd_pool;
160 objset_t *mos = dp->dp_meta_objset;
161 uint64_t zapobj;
162
163 mutex_enter(&ds->ds_lock);
164 if (ds->ds_phys->ds_userrefs_obj == 0) {
165 /*
166 * This is the first user hold for this dataset. Create
167 * the userrefs zap object.
168 */
169 dmu_buf_will_dirty(ds->ds_dbuf, tx);
170 zapobj = ds->ds_phys->ds_userrefs_obj =
171 zap_create(mos, DMU_OT_USERREFS, DMU_OT_NONE, 0, tx);
172 } else {
173 zapobj = ds->ds_phys->ds_userrefs_obj;
174 }
175 ds->ds_userrefs++;
176 mutex_exit(&ds->ds_lock);
177
178 VERIFY0(zap_add(mos, zapobj, htag, 8, 1, &now, tx));
179
180 if (minor != 0) {
181 char name[MAXNAMELEN];
182 nvlist_t *tags;
183
184 VERIFY0(dsl_pool_user_hold(dp, ds->ds_object,
185 htag, now, tx));
186 (void) snprintf(name, sizeof(name), "%llx",
187 (u_longlong_t)ds->ds_object);
188
189 if (nvlist_lookup_nvlist(dduha->dduha_tmpholds, name, &tags) != 0) {
190 tags = fnvlist_alloc();
191 fnvlist_add_boolean(tags, htag);
192 fnvlist_add_nvlist(dduha->dduha_tmpholds, name, tags);
193 fnvlist_free(tags);
194 } else {
195 fnvlist_add_boolean(tags, htag);
196 }
197 }
198
199 spa_history_log_internal_ds(ds, "hold", tx,
200 "tag=%s temp=%d refs=%llu",
201 htag, minor != 0, ds->ds_userrefs);
202 }
203
204 typedef struct zfs_hold_cleanup_arg {
205 char zhca_spaname[MAXNAMELEN];
206 uint64_t zhca_spa_load_guid;
207 nvlist_t *zhca_holds;
208 } zfs_hold_cleanup_arg_t;
209
210 static void
211 dsl_dataset_user_release_onexit(void *arg)
212 {
213 zfs_hold_cleanup_arg_t *ca = (zfs_hold_cleanup_arg_t *)arg;
214 spa_t *spa;
215 int error;
216
217 error = spa_open(ca->zhca_spaname, &spa, FTAG);
218 if (error != 0) {
219 zfs_dbgmsg("couldn't release holds on pool=%s "
220 "because pool is no longer loaded",
221 ca->zhca_spaname);
222 return;
223 }
224 if (spa_load_guid(spa) != ca->zhca_spa_load_guid) {
225 zfs_dbgmsg("couldn't release holds on pool=%s "
226 "because pool is no longer loaded (guid doesn't match)",
227 ca->zhca_spaname);
228 spa_close(spa, FTAG);
229 return;
230 }
231
232 (void) dsl_dataset_user_release_tmp(spa_get_dsl(spa), ca->zhca_holds);
233 fnvlist_free(ca->zhca_holds);
234 kmem_free(ca, sizeof(zfs_hold_cleanup_arg_t));
235 spa_close(spa, FTAG);
236 }
237
238 static void
239 dsl_register_onexit_hold_cleanup(spa_t *spa, nvlist_t *holds, minor_t minor)
240 {
241 zfs_hold_cleanup_arg_t *ca;
242
243 if (minor == 0 || nvlist_next_nvpair(holds, NULL) == NULL) {
244 fnvlist_free(holds);
245 return;
246 }
247
248 ASSERT(spa != NULL);
249 ca = kmem_alloc(sizeof (*ca), KM_SLEEP);
250
251 (void) strlcpy(ca->zhca_spaname, spa_name(spa),
252 sizeof (ca->zhca_spaname));
253 ca->zhca_spa_load_guid = spa_load_guid(spa);
254 ca->zhca_holds = holds;
255 VERIFY0(zfs_onexit_add_cb(minor,
256 dsl_dataset_user_release_onexit, ca, NULL));
257 }
258
259 void
260 dsl_dataset_user_hold_sync_one(dsl_dataset_t *ds, const char *htag,
261 minor_t minor, uint64_t now, dmu_tx_t *tx)
262 {
263 dsl_dataset_user_hold_arg_t dduha;
264
265 dduha.dduha_spa = NULL;
266 dduha.dduha_holds = NULL;
267 dduha.dduha_tmpholds = fnvlist_alloc();
268 dduha.dduha_errlist = NULL;
269 dduha.dduha_minor = minor;
270 dduha.dduha_holds_created = B_FALSE;
271
272 dsl_dataset_user_hold_sync_one_impl(&dduha, ds, htag, minor, now, tx);
273 dsl_register_onexit_hold_cleanup(dsl_dataset_get_spa(ds),
274 dduha.dduha_tmpholds, minor);
275 }
276
277 static void
278 dsl_dataset_user_hold_sync(void *arg, dmu_tx_t *tx)
279 {
280 dsl_dataset_user_hold_arg_t *dduha = arg;
281 dsl_pool_t *dp = dmu_tx_pool(tx);
282 nvpair_t *pair;
283 uint64_t now = gethrestime_sec();
284
285 for (pair = nvlist_next_nvpair(dduha->dduha_holds, NULL); pair != NULL;
286 pair = nvlist_next_nvpair(dduha->dduha_holds, pair)) {
287 dsl_dataset_t *ds;
288 char *name;
289 int error;
290
291 name = nvpair_name(pair);
292 error = dsl_dataset_hold(dp, name, FTAG, &ds);
293 if (error == 0) {
294 dsl_dataset_user_hold_sync_one_impl(dduha, ds,
295 fnvpair_value_string(pair), dduha->dduha_minor,
296 now, tx);
297 dsl_dataset_rele(ds, FTAG);
298 dduha->dduha_holds_created = B_TRUE;
299 } else if (dduha->dduha_errlist != NULL) {
300 /*
301 * We register ENOENT errors so they can be correctly
302 * reported if needed, such as when all holds fail.
303 */
304 fnvlist_add_int32(dduha->dduha_errlist, name, error);
305 }
306 }
307 dduha->dduha_spa = dp->dp_spa;
308 }
309
310 /*
311 * The full semantics of this function are described in the comment above
312 * lzc_hold().
313 *
314 * To summarize:
315 * holds is nvl of snapname -> holdname
316 * errlist will be filled in with snapname -> error
317 *
318 * The snaphosts must all be in the same pool.
319 *
320 * Holds for snapshots that don't exist will be skipped.
321 *
322 * If none of the snapshots for requested holds exist then ENOENT will be
323 * returned.
324 *
325 * If cleanup_minor is not 0, the holds will be temporary, which will be cleaned
326 * up when the process exits.
327 *
328 * On success all the holds, for snapshots that existed, will be created and 0
329 * will be returned.
330 *
331 * On failure no holds will be created, the errlist will be filled in,
332 * and an errno will returned.
333 *
334 * In all cases the errlist will contain entries for holds where the snapshot
335 * didn't exist.
336 */
337 int
338 dsl_dataset_user_hold(nvlist_t *holds, minor_t cleanup_minor, nvlist_t *errlist)
339 {
340 dsl_dataset_user_hold_arg_t dduha;
341 nvpair_t *pair;
342 int ret;
343
344 pair = nvlist_next_nvpair(holds, NULL);
345 if (pair == NULL)
346 return (0);
347
348 dduha.dduha_spa = NULL;
349 dduha.dduha_holds = holds;
350 dduha.dduha_tmpholds = fnvlist_alloc();
351 dduha.dduha_errlist = errlist;
352 dduha.dduha_minor = cleanup_minor;
353 dduha.dduha_holds_created = B_FALSE;
354
355 ret = dsl_sync_task(nvpair_name(pair), dsl_dataset_user_hold_check,
356 dsl_dataset_user_hold_sync, &dduha, fnvlist_num_pairs(holds));
357 if (ret == 0) {
358 /* Check we created at least one hold. */
359 if (dduha.dduha_holds_created) {
360 dsl_register_onexit_hold_cleanup(dduha.dduha_spa,
361 dduha.dduha_tmpholds, cleanup_minor);
362 } else {
363 fnvlist_free(dduha.dduha_tmpholds);
364 ret = ENOENT;
365 }
366 } else {
367 fnvlist_free(dduha.dduha_tmpholds);
368 }
369
370 return (ret);
371 }
372
373 typedef int (dsl_holdfunc_t)(dsl_pool_t *dp, const char *name, void *tag,
374 dsl_dataset_t **dsp);
375
376 typedef struct dsl_dataset_user_release_arg {
377 dsl_holdfunc_t *ddura_holdfunc;
378 nvlist_t *ddura_holds;
379 nvlist_t *ddura_todelete;
380 nvlist_t *ddura_errlist;
381 boolean_t ddura_holds_found;
382 } dsl_dataset_user_release_arg_t;
383
384 /* Place a dataset hold on the snapshot identified by passed dsobj string */
385 static
386 int dsl_dataset_hold_byobj(dsl_pool_t *dp, const char *dsobj, void *tag,
387 dsl_dataset_t **dsp)
388 {
389 return dsl_dataset_hold_obj(dp, strtonum(dsobj, NULL), tag, dsp);
390 }
391
392 static int
393 dsl_dataset_user_release_check_one(dsl_dataset_user_release_arg_t *ddura,
394 dsl_dataset_t *ds, nvlist_t *holds, boolean_t *todelete)
395 {
396 uint64_t zapobj;
397 nvpair_t *pair;
398 objset_t *mos = ds->ds_dir->dd_pool->dp_meta_objset;
399 int error;
400 int numholds = 0;
401 int ret;
402
403 *todelete = B_FALSE;
404 ret = 0;
405
406 if (!dsl_dataset_is_snapshot(ds))
407 return (SET_ERROR(EINVAL));
408
409 zapobj = ds->ds_phys->ds_userrefs_obj;
410 if (zapobj == 0)
411 return (SET_ERROR(ESRCH));
412
413 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
414 pair = nvlist_next_nvpair(holds, pair)) {
415 uint64_t tmp;
416
417 error = zap_lookup(mos, zapobj, nvpair_name(pair), 8, 1, &tmp);
418 /* Non-existent holds aren't always fatal. */
419 if (error == ENOENT) {
420 ret = error;
421 continue;
422 }
423 if (error != 0)
424 return (error);
425 numholds++;
426 }
427
428 if (DS_IS_DEFER_DESTROY(ds) && ds->ds_phys->ds_num_children == 1 &&
429 ds->ds_userrefs == numholds) {
430 /* we need to destroy the snapshot as well */
431
432 if (dsl_dataset_long_held(ds))
433 return (SET_ERROR(EBUSY));
434 *todelete = B_TRUE;
435 }
436
437 if (numholds != 0)
438 ddura->ddura_holds_found = B_TRUE;
439
440 return (ret);
441 }
442
443 static int
444 dsl_dataset_user_release_check(void *arg, dmu_tx_t *tx)
445 {
446 dsl_dataset_user_release_arg_t *ddura = arg;
447 dsl_holdfunc_t *holdfunc = ddura->ddura_holdfunc;
448 dsl_pool_t *dp = dmu_tx_pool(tx);
449 nvpair_t *pair;
450 int rv = 0;
451
452 if (!dmu_tx_is_syncing(tx))
453 return (0);
454
455 for (pair = nvlist_next_nvpair(ddura->ddura_holds, NULL); pair != NULL;
456 pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
457 const char *name = nvpair_name(pair);
458 int error;
459 dsl_dataset_t *ds;
460 nvlist_t *holds;
461
462 error = nvpair_value_nvlist(pair, &holds);
463 if (error != 0)
464 return (SET_ERROR(EINVAL));
465
466 error = holdfunc(dp, name, FTAG, &ds);
467 if (error == 0) {
468 boolean_t deleteme;
469 error = dsl_dataset_user_release_check_one(ddura, ds,
470 holds, &deleteme);
471 /*
472 * Don't check for error == 0 as deleteme is only set
473 * to B_TRUE if it's correct to do so dispite the error
474 * e.g. ENOENT.
475 */
476 if (deleteme) {
477 fnvlist_add_boolean(ddura->ddura_todelete,
478 name);
479 }
480 dsl_dataset_rele(ds, FTAG);
481 }
482 if (error != 0) {
483 if (ddura->ddura_errlist != NULL) {
484 fnvlist_add_int32(ddura->ddura_errlist,
485 name, error);
486 }
487 /* Non-existent holds aren't always fatal. */
488 if (error != ENOENT)
489 rv = error;
490 }
491 }
492
493 /*
494 * None of the specified holds existed so avoid the overhead of a sync
495 * and return ENOENT.
496 */
497 if (rv == 0 && !ddura->ddura_holds_found)
498 rv = ENOENT;
499
500 return (rv);
501 }
502
503 static void
504 dsl_dataset_user_release_sync_one(dsl_dataset_user_release_arg_t *ddura,
505 dsl_dataset_t *ds, nvlist_t *holds, dmu_tx_t *tx)
506 {
507 dsl_pool_t *dp = ds->ds_dir->dd_pool;
508 objset_t *mos = dp->dp_meta_objset;
509 nvpair_t *pair;
510
511 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
512 pair = nvlist_next_nvpair(holds, pair)) {
513 uint64_t zapobj;
514 int error;
515 char *name;
516
517 name = nvpair_name(pair);
518
519 /* Remove temporary hold if one exists. */
520 error = dsl_pool_user_release(dp, ds->ds_object, name, tx);
521 VERIFY(error == 0 || error == ENOENT);
522
523 /* Remove user hold if one exists. */
524 zapobj = ds->ds_phys->ds_userrefs_obj;
525 error = zap_remove(mos, zapobj, name, tx);
526 if (error == ENOENT)
527 continue;
528 VERIFY0(error);
529
530 /* Only if we removed a hold do we decrement userrefs. */
531 mutex_enter(&ds->ds_lock);
532 ds->ds_userrefs--;
533 mutex_exit(&ds->ds_lock);
534
535 ddura->ddura_holds_found = B_TRUE;
536
537 spa_history_log_internal_ds(ds, "release", tx,
538 "tag=%s refs=%lld", nvpair_name(pair),
539 (longlong_t)ds->ds_userrefs);
540 }
541 }
542
543 static void
544 dsl_dataset_user_release_sync(void *arg, dmu_tx_t *tx)
545 {
546 dsl_dataset_user_release_arg_t *ddura = arg;
547 dsl_holdfunc_t *holdfunc = ddura->ddura_holdfunc;
548 dsl_pool_t *dp = dmu_tx_pool(tx);
549 nvpair_t *pair;
550
551 /*
552 * Even though check suggested that at least one of our holds where
553 * found this may have changed. Recalculate ddura_holds_found so that
554 * we can return ENOENT from the caller in the case that no holds
555 * where actually released.
556 */
557 ddura->ddura_holds_found = B_FALSE;
558
559 for (pair = nvlist_next_nvpair(ddura->ddura_holds, NULL); pair != NULL;
560 pair = nvlist_next_nvpair(ddura->ddura_holds, pair)) {
561 dsl_dataset_t *ds;
562 int error;
563
564 error = holdfunc(dp, nvpair_name(pair), FTAG, &ds);
565 if (error == ENOENT)
566 continue;
567 VERIFY0(error);
568
569 dsl_dataset_user_release_sync_one(ddura, ds,
570 fnvpair_value_nvlist(pair), tx);
571 if (nvlist_exists(ddura->ddura_todelete, nvpair_name(pair))) {
572 ASSERT(ds->ds_userrefs == 0 &&
573 ds->ds_phys->ds_num_children == 1 &&
574 DS_IS_DEFER_DESTROY(ds));
575 dsl_destroy_snapshot_sync_impl(ds, B_FALSE, tx);
576 }
577 dsl_dataset_rele(ds, FTAG);
578 }
579 }
580
581 /*
582 * The full semantics of this function are described in the comment above
583 * lzc_release().
584 *
585 * To summarize:
586 * Releases holds specified in the nvl holds.
587 *
588 * holds is nvl of snapname -> { holdname, ... }
589 * errlist will be filled in with snapname -> error
590 *
591 * If tmpdp is not NULL the names for holds should be the dbobj's of snapshots,
592 * otherwise they should be the names of shapshots.
593 *
594 * As a release may cause snapshots to be destroyed this trys to ensure they
595 * aren't mounted.
596 *
597 * The release of non-existent holds are skipped.
598 *
599 * At least one hold must have been released for the this function to succeed
600 * and return 0.
601 */
602 static int
603 dsl_dataset_user_release_impl(nvlist_t *holds, nvlist_t *errlist,
604 dsl_pool_t *tmpdp)
605 {
606 dsl_dataset_user_release_arg_t ddura;
607 nvpair_t *pair;
608 char *pool;
609 int error;
610
611 pair = nvlist_next_nvpair(holds, NULL);
612 if (pair == NULL)
613 return (0);
614
615 #ifdef _KERNEL
616 /*
617 * The release may cause snapshots to be destroyed; make sure they
618 * are not mounted.
619 */
620 if (tmpdp != NULL) {
621 /* Temporary holds are specified by dbobj. */
622 ddura.ddura_holdfunc = dsl_dataset_hold_byobj;
623 pool = spa_name(tmpdp->dp_spa);
624
625 dsl_pool_config_enter(tmpdp, FTAG);
626 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
627 pair = nvlist_next_nvpair(holds, pair)) {
628 dsl_dataset_t *ds;
629
630 error = dsl_dataset_hold_byobj(tmpdp, nvpair_name(pair),
631 FTAG, &ds);
632 if (error == 0) {
633 char name[MAXNAMELEN];
634 dsl_dataset_name(ds, name);
635 dsl_dataset_rele(ds, FTAG);
636 zfs_unmount_snap(name);
637 }
638 }
639 dsl_pool_config_exit(tmpdp, FTAG);
640 } else {
641 /* Non-temporary holds are specified by name. */
642 ddura.ddura_holdfunc = dsl_dataset_hold;
643 pool = nvpair_name(pair);
644
645 for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
646 pair = nvlist_next_nvpair(holds, pair))
647 zfs_unmount_snap(nvpair_name(pair));
648 }
649 #endif
650
651 ddura.ddura_holds = holds;
652 ddura.ddura_errlist = errlist;
653 ddura.ddura_todelete = fnvlist_alloc();
654 ddura.ddura_holds_found = B_FALSE;
655
656 error = dsl_sync_task(pool, dsl_dataset_user_release_check,
657 dsl_dataset_user_release_sync, &ddura,
658 fnvlist_num_pairs(holds));
659 fnvlist_free(ddura.ddura_todelete);
660
661 /* If at least one hold wasn't removed return ENOENT. */
662 if (error == 0 && !ddura.ddura_holds_found)
663 error = ENOENT;
664
665 return (error);
666 }
667
668 /*
669 * holds is nvl of snapname -> { holdname, ... }
670 * errlist will be filled in with snapname -> error
671 *
672 * if any fails, all will fail.
673 */
674 int
675 dsl_dataset_user_release(nvlist_t *holds, nvlist_t *errlist)
676 {
677 return dsl_dataset_user_release_impl(holds, errlist, NULL);
678 }
679
680 /*
681 * holds is nvl of snapdsobj -> { holdname, ... }
682 */
683 void
684 dsl_dataset_user_release_tmp(struct dsl_pool *dp, nvlist_t *holds)
685 {
686 ASSERT(dp != NULL);
687 (void) dsl_dataset_user_release_impl(holds, NULL, dp);
688 }
689
690 int
691 dsl_dataset_get_holds(const char *dsname, nvlist_t *nvl)
692 {
693 dsl_pool_t *dp;
694 dsl_dataset_t *ds;
695 int err;
696
697 err = dsl_pool_hold(dsname, FTAG, &dp);
698 if (err != 0)
699 return (err);
700 err = dsl_dataset_hold(dp, dsname, FTAG, &ds);
701 if (err != 0) {
702 dsl_pool_rele(dp, FTAG);
703 return (err);
704 }
705
706 if (ds->ds_phys->ds_userrefs_obj != 0) {
707 zap_attribute_t *za;
|