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) 2011, 2017 by Delphix. All rights reserved.
24 * Copyright (c) 2013 Steven Hartland. All rights reserved.
25 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
26 * Copyright (c) 2014 Integros [integros.com]
27 * Copyright 2016 Nexenta Systems, Inc. All rights reserved.
28 */
29
30 #include <sys/dsl_pool.h>
31 #include <sys/dsl_dataset.h>
32 #include <sys/dsl_prop.h>
33 #include <sys/dsl_dir.h>
34 #include <sys/dsl_synctask.h>
35 #include <sys/dsl_scan.h>
36 #include <sys/dnode.h>
37 #include <sys/dmu_tx.h>
38 #include <sys/dmu_objset.h>
39 #include <sys/arc.h>
40 #include <sys/zap.h>
41 #include <sys/zio.h>
42 #include <sys/zfs_context.h>
43 #include <sys/fs/zfs.h>
44 #include <sys/zfs_znode.h>
45 #include <sys/spa_impl.h>
46 #include <sys/dsl_deadlist.h>
47 #include <sys/bptree.h>
48 #include <sys/zfeature.h>
49 #include <sys/zil_impl.h>
50 #include <sys/dsl_userhold.h>
51
52 /*
53 * ZFS Write Throttle
54 * ------------------
55 *
56 * ZFS must limit the rate of incoming writes to the rate at which it is able
57 * to sync data modifications to the backend storage. Throttling by too much
58 * creates an artificial limit; throttling by too little can only be sustained
59 * for short periods and would lead to highly lumpy performance. On a per-pool
60 * basis, ZFS tracks the amount of modified (dirty) data. As operations change
61 * data, the amount of dirty data increases; as ZFS syncs out data, the amount
62 * of dirty data decreases. When the amount of dirty data exceeds a
63 * predetermined threshold further modifications are blocked until the amount
64 * of dirty data decreases (as data is synced out).
65 *
66 * The limit on dirty data is tunable, and should be adjusted according to
67 * both the IO capacity and available memory of the system. The larger the
68 * window, the more ZFS is able to aggregate and amortize metadata (and data)
69 * changes. However, memory is a limited resource, and allowing for more dirty
70 * data comes at the cost of keeping other useful data in memory (for example
71 * ZFS data cached by the ARC).
72 *
73 * Implementation
74 *
75 * As buffers are modified dsl_pool_willuse_space() increments both the per-
76 * txg (dp_dirty_pertxg[]) and poolwide (dp_dirty_total) accounting of
77 * dirty space used; dsl_pool_dirty_space() decrements those values as data
78 * is synced out from dsl_pool_sync(). While only the poolwide value is
79 * relevant, the per-txg value is useful for debugging. The tunable
80 * zfs_dirty_data_max determines the dirty space limit. Once that value is
81 * exceeded, new writes are halted until space frees up.
82 *
83 * The zfs_dirty_data_sync tunable dictates the threshold at which we
84 * ensure that there is a txg syncing (see the comment in txg.c for a full
85 * description of transaction group stages).
86 *
87 * The IO scheduler uses both the dirty space limit and current amount of
88 * dirty data as inputs. Those values affect the number of concurrent IOs ZFS
89 * issues. See the comment in vdev_queue.c for details of the IO scheduler.
90 *
91 * The delay is also calculated based on the amount of dirty data. See the
92 * comment above dmu_tx_delay() for details.
93 */
94
95 /*
96 * zfs_dirty_data_max will be set to zfs_dirty_data_max_percent% of all memory,
97 * capped at zfs_dirty_data_max_max. It can also be overridden in /etc/system.
98 */
99 uint64_t zfs_dirty_data_max;
100 uint64_t zfs_dirty_data_max_max = 4ULL * 1024 * 1024 * 1024;
101 int zfs_dirty_data_max_percent = 10;
102
103 /*
104 * If there is at least this much dirty data, push out a txg.
105 */
106 uint64_t zfs_dirty_data_sync = 64 * 1024 * 1024;
107
108 /*
109 * Once there is this amount of dirty data, the dmu_tx_delay() will kick in
110 * and delay each transaction.
111 * This value should be >= zfs_vdev_async_write_active_max_dirty_percent.
112 */
113 int zfs_delay_min_dirty_percent = 60;
114
115 /*
116 * This controls how quickly the delay approaches infinity.
117 * Larger values cause it to delay more for a given amount of dirty data.
118 * Therefore larger values will cause there to be less dirty data for a
119 * given throughput.
120 *
121 * For the smoothest delay, this value should be about 1 billion divided
122 * by the maximum number of operations per second. This will smoothly
123 * handle between 10x and 1/10th this number.
124 *
125 * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the
126 * multiply in dmu_tx_delay().
127 */
128 uint64_t zfs_delay_scale = 1000 * 1000 * 1000 / 2000;
129
130 /*
131 * This determines the number of threads used by the dp_sync_taskq.
132 */
133 int zfs_sync_taskq_batch_pct = 75;
134
135 /*
136 * These tunables determine the behavior of how zil_itxg_clean() is
137 * called via zil_clean() in the context of spa_sync(). When an itxg
138 * list needs to be cleaned, TQ_NOSLEEP will be used when dispatching.
139 * If the dispatch fails, the call to zil_itxg_clean() will occur
140 * synchronously in the context of spa_sync(), which can negatively
141 * impact the performance of spa_sync() (e.g. in the case of the itxg
142 * list having a large number of itxs that needs to be cleaned).
143 *
144 * Thus, these tunables can be used to manipulate the behavior of the
145 * taskq used by zil_clean(); they determine the number of taskq entries
146 * that are pre-populated when the taskq is first created (via the
147 * "zfs_zil_clean_taskq_minalloc" tunable) and the maximum number of
148 * taskq entries that are cached after an on-demand allocation (via the
149 * "zfs_zil_clean_taskq_maxalloc").
150 *
151 * The idea being, we want to try reasonably hard to ensure there will
152 * already be a taskq entry pre-allocated by the time that it is needed
153 * by zil_clean(). This way, we can avoid the possibility of an
154 * on-demand allocation of a new taskq entry from failing, which would
155 * result in zil_itxg_clean() being called synchronously from zil_clean()
156 * (which can adversely affect performance of spa_sync()).
157 *
158 * Additionally, the number of threads used by the taskq can be
159 * configured via the "zfs_zil_clean_taskq_nthr_pct" tunable.
160 */
161 int zfs_zil_clean_taskq_nthr_pct = 100;
162 int zfs_zil_clean_taskq_minalloc = 1024;
163 int zfs_zil_clean_taskq_maxalloc = 1024 * 1024;
164
165 int
166 dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
167 {
168 uint64_t obj;
169 int err;
170
171 err = zap_lookup(dp->dp_meta_objset,
172 dsl_dir_phys(dp->dp_root_dir)->dd_child_dir_zapobj,
173 name, sizeof (obj), 1, &obj);
174 if (err)
175 return (err);
176
177 return (dsl_dir_hold_obj(dp, obj, name, dp, ddp));
178 }
179
180 static dsl_pool_t *
181 dsl_pool_open_impl(spa_t *spa, uint64_t txg)
182 {
183 dsl_pool_t *dp;
184 blkptr_t *bp = spa_get_rootblkptr(spa);
185
186 dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
187 dp->dp_spa = spa;
188 dp->dp_meta_rootbp = *bp;
189 rrw_init(&dp->dp_config_rwlock, B_TRUE);
190 txg_init(dp, txg);
191
192 txg_list_create(&dp->dp_dirty_datasets, spa,
193 offsetof(dsl_dataset_t, ds_dirty_link));
194 txg_list_create(&dp->dp_dirty_zilogs, spa,
195 offsetof(zilog_t, zl_dirty_link));
196 txg_list_create(&dp->dp_dirty_dirs, spa,
197 offsetof(dsl_dir_t, dd_dirty_link));
198 txg_list_create(&dp->dp_sync_tasks, spa,
199 offsetof(dsl_sync_task_t, dst_node));
200
201 dp->dp_sync_taskq = taskq_create("dp_sync_taskq",
202 zfs_sync_taskq_batch_pct, minclsyspri, 1, INT_MAX,
203 TASKQ_THREADS_CPU_PCT);
204
205 dp->dp_zil_clean_taskq = taskq_create("dp_zil_clean_taskq",
206 zfs_zil_clean_taskq_nthr_pct, minclsyspri,
207 zfs_zil_clean_taskq_minalloc,
208 zfs_zil_clean_taskq_maxalloc,
209 TASKQ_PREPOPULATE | TASKQ_THREADS_CPU_PCT);
210
211 mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
212 cv_init(&dp->dp_spaceavail_cv, NULL, CV_DEFAULT, NULL);
213
214 dp->dp_vnrele_taskq = taskq_create("zfs_vn_rele_taskq", 1, minclsyspri,
215 1, 4, 0);
216
217 return (dp);
218 }
219
220 int
221 dsl_pool_init(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
222 {
223 int err;
224 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
225
226 err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,
227 &dp->dp_meta_objset);
228 if (err != 0)
229 dsl_pool_close(dp);
230 else
231 *dpp = dp;
232
233 return (err);
234 }
235
236 int
237 dsl_pool_open(dsl_pool_t *dp)
238 {
239 int err;
240 dsl_dir_t *dd;
241 dsl_dataset_t *ds;
242 uint64_t obj;
243
244 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
245 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
246 DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
247 &dp->dp_root_dir_obj);
248 if (err)
249 goto out;
250
251 err = dsl_dir_hold_obj(dp, dp->dp_root_dir_obj,
252 NULL, dp, &dp->dp_root_dir);
253 if (err)
254 goto out;
255
256 err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir);
257 if (err)
258 goto out;
259
260 if (spa_version(dp->dp_spa) >= SPA_VERSION_ORIGIN) {
261 err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd);
262 if (err)
263 goto out;
264 err = dsl_dataset_hold_obj(dp,
265 dsl_dir_phys(dd)->dd_head_dataset_obj, FTAG, &ds);
266 if (err == 0) {
267 err = dsl_dataset_hold_obj(dp,
268 dsl_dataset_phys(ds)->ds_prev_snap_obj, dp,
269 &dp->dp_origin_snap);
270 dsl_dataset_rele(ds, FTAG);
271 }
272 dsl_dir_rele(dd, dp);
273 if (err)
274 goto out;
275 }
276
277 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
278 err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME,
279 &dp->dp_free_dir);
280 if (err)
281 goto out;
282
283 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
284 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj);
285 if (err)
286 goto out;
287 VERIFY0(bpobj_open(&dp->dp_free_bpobj,
288 dp->dp_meta_objset, obj));
289 }
290
291 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_OBSOLETE_COUNTS)) {
292 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
293 DMU_POOL_OBSOLETE_BPOBJ, sizeof (uint64_t), 1, &obj);
294 if (err == 0) {
295 VERIFY0(bpobj_open(&dp->dp_obsolete_bpobj,
296 dp->dp_meta_objset, obj));
297 } else if (err == ENOENT) {
298 /*
299 * We might not have created the remap bpobj yet.
300 */
301 err = 0;
302 } else {
303 goto out;
304 }
305 }
306
307 /*
308 * Note: errors ignored, because the these special dirs, used for
309 * space accounting, are only created on demand.
310 */
311 (void) dsl_pool_open_special_dir(dp, LEAK_DIR_NAME,
312 &dp->dp_leak_dir);
313
314 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_ASYNC_DESTROY)) {
315 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
316 DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
317 &dp->dp_bptree_obj);
318 if (err != 0)
319 goto out;
320 }
321
322 if (spa_feature_is_active(dp->dp_spa, SPA_FEATURE_EMPTY_BPOBJ)) {
323 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
324 DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
325 &dp->dp_empty_bpobj);
326 if (err != 0)
327 goto out;
328 }
329
330 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
331 DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
332 &dp->dp_tmp_userrefs_obj);
333 if (err == ENOENT)
334 err = 0;
335 if (err)
336 goto out;
337
338 err = dsl_scan_init(dp, dp->dp_tx.tx_open_txg);
339
340 out:
341 rrw_exit(&dp->dp_config_rwlock, FTAG);
342 return (err);
343 }
344
345 void
346 dsl_pool_close(dsl_pool_t *dp)
347 {
348 /*
349 * Drop our references from dsl_pool_open().
350 *
351 * Since we held the origin_snap from "syncing" context (which
352 * includes pool-opening context), it actually only got a "ref"
353 * and not a hold, so just drop that here.
354 */
355 if (dp->dp_origin_snap != NULL)
356 dsl_dataset_rele(dp->dp_origin_snap, dp);
357 if (dp->dp_mos_dir != NULL)
358 dsl_dir_rele(dp->dp_mos_dir, dp);
359 if (dp->dp_free_dir != NULL)
360 dsl_dir_rele(dp->dp_free_dir, dp);
361 if (dp->dp_leak_dir != NULL)
362 dsl_dir_rele(dp->dp_leak_dir, dp);
363 if (dp->dp_root_dir != NULL)
364 dsl_dir_rele(dp->dp_root_dir, dp);
365
366 bpobj_close(&dp->dp_free_bpobj);
367 bpobj_close(&dp->dp_obsolete_bpobj);
368
369 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
370 if (dp->dp_meta_objset != NULL)
371 dmu_objset_evict(dp->dp_meta_objset);
372
373 txg_list_destroy(&dp->dp_dirty_datasets);
374 txg_list_destroy(&dp->dp_dirty_zilogs);
375 txg_list_destroy(&dp->dp_sync_tasks);
376 txg_list_destroy(&dp->dp_dirty_dirs);
377
378 taskq_destroy(dp->dp_zil_clean_taskq);
379 taskq_destroy(dp->dp_sync_taskq);
380
381 /*
382 * We can't set retry to TRUE since we're explicitly specifying
383 * a spa to flush. This is good enough; any missed buffers for
384 * this spa won't cause trouble, and they'll eventually fall
385 * out of the ARC just like any other unused buffer.
386 */
387 arc_flush(dp->dp_spa, FALSE);
388
389 txg_fini(dp);
390 dsl_scan_fini(dp);
391 dmu_buf_user_evict_wait();
392
393 rrw_destroy(&dp->dp_config_rwlock);
394 mutex_destroy(&dp->dp_lock);
395 taskq_destroy(dp->dp_vnrele_taskq);
396 if (dp->dp_blkstats != NULL)
397 kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
398 kmem_free(dp, sizeof (dsl_pool_t));
399 }
400
401 void
402 dsl_pool_create_obsolete_bpobj(dsl_pool_t *dp, dmu_tx_t *tx)
403 {
404 uint64_t obj;
405 /*
406 * Currently, we only create the obsolete_bpobj where there are
407 * indirect vdevs with referenced mappings.
408 */
409 ASSERT(spa_feature_is_active(dp->dp_spa, SPA_FEATURE_DEVICE_REMOVAL));
410 /* create and open the obsolete_bpobj */
411 obj = bpobj_alloc(dp->dp_meta_objset, SPA_OLD_MAXBLOCKSIZE, tx);
412 VERIFY0(bpobj_open(&dp->dp_obsolete_bpobj, dp->dp_meta_objset, obj));
413 VERIFY0(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
414 DMU_POOL_OBSOLETE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
415 spa_feature_incr(dp->dp_spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
416 }
417
418 void
419 dsl_pool_destroy_obsolete_bpobj(dsl_pool_t *dp, dmu_tx_t *tx)
420 {
421 spa_feature_decr(dp->dp_spa, SPA_FEATURE_OBSOLETE_COUNTS, tx);
422 VERIFY0(zap_remove(dp->dp_meta_objset,
423 DMU_POOL_DIRECTORY_OBJECT,
424 DMU_POOL_OBSOLETE_BPOBJ, tx));
425 bpobj_free(dp->dp_meta_objset,
426 dp->dp_obsolete_bpobj.bpo_object, tx);
427 bpobj_close(&dp->dp_obsolete_bpobj);
428 }
429
430 dsl_pool_t *
431 dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)
432 {
433 int err;
434 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
435 dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
436 dsl_dataset_t *ds;
437 uint64_t obj;
438
439 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
440
441 /* create and open the MOS (meta-objset) */
442 dp->dp_meta_objset = dmu_objset_create_impl(spa,
443 NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);
444
445 /* create the pool directory */
446 err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
447 DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
448 ASSERT0(err);
449
450 /* Initialize scan structures */
451 VERIFY0(dsl_scan_init(dp, txg));
452
453 /* create and open the root dir */
454 dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);
455 VERIFY0(dsl_dir_hold_obj(dp, dp->dp_root_dir_obj,
456 NULL, dp, &dp->dp_root_dir));
457
458 /* create and open the meta-objset dir */
459 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);
460 VERIFY0(dsl_pool_open_special_dir(dp,
461 MOS_DIR_NAME, &dp->dp_mos_dir));
462
463 if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
464 /* create and open the free dir */
465 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
466 FREE_DIR_NAME, tx);
467 VERIFY0(dsl_pool_open_special_dir(dp,
468 FREE_DIR_NAME, &dp->dp_free_dir));
469
470 /* create and open the free_bplist */
471 obj = bpobj_alloc(dp->dp_meta_objset, SPA_OLD_MAXBLOCKSIZE, tx);
472 VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
473 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0);
474 VERIFY0(bpobj_open(&dp->dp_free_bpobj,
475 dp->dp_meta_objset, obj));
476 }
477
478 if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB)
479 dsl_pool_create_origin(dp, tx);
480
481 /* create the root dataset */
482 obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);
483
484 /* create the root objset */
485 VERIFY0(dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
486 #ifdef _KERNEL
487 {
488 objset_t *os;
489 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
490 os = dmu_objset_create_impl(dp->dp_spa, ds,
491 dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx);
492 rrw_exit(&ds->ds_bp_rwlock, FTAG);
493 zfs_create_fs(os, kcred, zplprops, tx);
494 }
495 #endif
496 dsl_dataset_rele(ds, FTAG);
497
498 dmu_tx_commit(tx);
499
500 rrw_exit(&dp->dp_config_rwlock, FTAG);
501
502 return (dp);
503 }
504
505 /*
506 * Account for the meta-objset space in its placeholder dsl_dir.
507 */
508 void
509 dsl_pool_mos_diduse_space(dsl_pool_t *dp,
510 int64_t used, int64_t comp, int64_t uncomp)
511 {
512 ASSERT3U(comp, ==, uncomp); /* it's all metadata */
513 mutex_enter(&dp->dp_lock);
514 dp->dp_mos_used_delta += used;
515 dp->dp_mos_compressed_delta += comp;
516 dp->dp_mos_uncompressed_delta += uncomp;
517 mutex_exit(&dp->dp_lock);
518 }
519
520 static void
521 dsl_pool_sync_mos(dsl_pool_t *dp, dmu_tx_t *tx)
522 {
523 zio_t *zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
524 dmu_objset_sync(dp->dp_meta_objset, zio, tx);
525 VERIFY0(zio_wait(zio));
526 dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
527 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
528 }
529
530 static void
531 dsl_pool_dirty_delta(dsl_pool_t *dp, int64_t delta)
532 {
533 ASSERT(MUTEX_HELD(&dp->dp_lock));
534
535 if (delta < 0)
536 ASSERT3U(-delta, <=, dp->dp_dirty_total);
537
538 dp->dp_dirty_total += delta;
539
540 /*
541 * Note: we signal even when increasing dp_dirty_total.
542 * This ensures forward progress -- each thread wakes the next waiter.
543 */
544 if (dp->dp_dirty_total < zfs_dirty_data_max)
545 cv_signal(&dp->dp_spaceavail_cv);
546 }
547
548 void
549 dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
550 {
551 zio_t *zio;
552 dmu_tx_t *tx;
553 dsl_dir_t *dd;
554 dsl_dataset_t *ds;
555 objset_t *mos = dp->dp_meta_objset;
556 list_t synced_datasets;
557
558 list_create(&synced_datasets, sizeof (dsl_dataset_t),
559 offsetof(dsl_dataset_t, ds_synced_link));
560
561 tx = dmu_tx_create_assigned(dp, txg);
562
563 /*
564 * Write out all dirty blocks of dirty datasets.
565 */
566 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
567 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) {
568 /*
569 * We must not sync any non-MOS datasets twice, because
570 * we may have taken a snapshot of them. However, we
571 * may sync newly-created datasets on pass 2.
572 */
573 ASSERT(!list_link_active(&ds->ds_synced_link));
574 list_insert_tail(&synced_datasets, ds);
575 dsl_dataset_sync(ds, zio, tx);
576 }
577 VERIFY0(zio_wait(zio));
578
579 /*
580 * We have written all of the accounted dirty data, so our
581 * dp_space_towrite should now be zero. However, some seldom-used
582 * code paths do not adhere to this (e.g. dbuf_undirty(), also
583 * rounding error in dbuf_write_physdone).
584 * Shore up the accounting of any dirtied space now.
585 */
586 dsl_pool_undirty_space(dp, dp->dp_dirty_pertxg[txg & TXG_MASK], txg);
587
588 /*
589 * Update the long range free counter after
590 * we're done syncing user data
591 */
592 mutex_enter(&dp->dp_lock);
593 ASSERT(spa_sync_pass(dp->dp_spa) == 1 ||
594 dp->dp_long_free_dirty_pertxg[txg & TXG_MASK] == 0);
595 dp->dp_long_free_dirty_pertxg[txg & TXG_MASK] = 0;
596 mutex_exit(&dp->dp_lock);
597
598 /*
599 * After the data blocks have been written (ensured by the zio_wait()
600 * above), update the user/group space accounting. This happens
601 * in tasks dispatched to dp_sync_taskq, so wait for them before
602 * continuing.
603 */
604 for (ds = list_head(&synced_datasets); ds != NULL;
605 ds = list_next(&synced_datasets, ds)) {
606 dmu_objset_do_userquota_updates(ds->ds_objset, tx);
607 }
608 taskq_wait(dp->dp_sync_taskq);
609
610 /*
611 * Sync the datasets again to push out the changes due to
612 * userspace updates. This must be done before we process the
613 * sync tasks, so that any snapshots will have the correct
614 * user accounting information (and we won't get confused
615 * about which blocks are part of the snapshot).
616 */
617 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
618 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) != NULL) {
619 ASSERT(list_link_active(&ds->ds_synced_link));
620 dmu_buf_rele(ds->ds_dbuf, ds);
621 dsl_dataset_sync(ds, zio, tx);
622 }
623 VERIFY0(zio_wait(zio));
624
625 /*
626 * Now that the datasets have been completely synced, we can
627 * clean up our in-memory structures accumulated while syncing:
628 *
629 * - move dead blocks from the pending deadlist to the on-disk deadlist
630 * - release hold from dsl_dataset_dirty()
631 */
632 while ((ds = list_remove_head(&synced_datasets)) != NULL) {
633 dsl_dataset_sync_done(ds, tx);
634 }
635 while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)) != NULL) {
636 dsl_dir_sync(dd, tx);
637 }
638
639 /*
640 * The MOS's space is accounted for in the pool/$MOS
641 * (dp_mos_dir). We can't modify the mos while we're syncing
642 * it, so we remember the deltas and apply them here.
643 */
644 if (dp->dp_mos_used_delta != 0 || dp->dp_mos_compressed_delta != 0 ||
645 dp->dp_mos_uncompressed_delta != 0) {
646 dsl_dir_diduse_space(dp->dp_mos_dir, DD_USED_HEAD,
647 dp->dp_mos_used_delta,
648 dp->dp_mos_compressed_delta,
649 dp->dp_mos_uncompressed_delta, tx);
650 dp->dp_mos_used_delta = 0;
651 dp->dp_mos_compressed_delta = 0;
652 dp->dp_mos_uncompressed_delta = 0;
653 }
654
655 if (!multilist_is_empty(mos->os_dirty_dnodes[txg & TXG_MASK])) {
656 dsl_pool_sync_mos(dp, tx);
657 }
658
659 /*
660 * If we modify a dataset in the same txg that we want to destroy it,
661 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
662 * dsl_dir_destroy_check() will fail if there are unexpected holds.
663 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
664 * and clearing the hold on it) before we process the sync_tasks.
665 * The MOS data dirtied by the sync_tasks will be synced on the next
666 * pass.
667 */
668 if (!txg_list_empty(&dp->dp_sync_tasks, txg)) {
669 dsl_sync_task_t *dst;
670 /*
671 * No more sync tasks should have been added while we
672 * were syncing.
673 */
674 ASSERT3U(spa_sync_pass(dp->dp_spa), ==, 1);
675 while ((dst = txg_list_remove(&dp->dp_sync_tasks, txg)) != NULL)
676 dsl_sync_task_sync(dst, tx);
677 }
678
679 dmu_tx_commit(tx);
680
681 DTRACE_PROBE2(dsl_pool_sync__done, dsl_pool_t *dp, dp, uint64_t, txg);
682 }
683
684 void
685 dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)
686 {
687 zilog_t *zilog;
688
689 while (zilog = txg_list_head(&dp->dp_dirty_zilogs, txg)) {
690 dsl_dataset_t *ds = dmu_objset_ds(zilog->zl_os);
691 /*
692 * We don't remove the zilog from the dp_dirty_zilogs
693 * list until after we've cleaned it. This ensures that
694 * callers of zilog_is_dirty() receive an accurate
695 * answer when they are racing with the spa sync thread.
696 */
697 zil_clean(zilog, txg);
698 (void) txg_list_remove_this(&dp->dp_dirty_zilogs, zilog, txg);
699 ASSERT(!dmu_objset_is_dirty(zilog->zl_os, txg));
700 dmu_buf_rele(ds->ds_dbuf, zilog);
701 }
702 ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));
703 }
704
705 /*
706 * TRUE if the current thread is the tx_sync_thread or if we
707 * are being called from SPA context during pool initialization.
708 */
709 int
710 dsl_pool_sync_context(dsl_pool_t *dp)
711 {
712 return (curthread == dp->dp_tx.tx_sync_thread ||
713 spa_is_initializing(dp->dp_spa) ||
714 taskq_member(dp->dp_sync_taskq, curthread));
715 }
716
717 uint64_t
718 dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree)
719 {
720 uint64_t space, resv;
721
722 /*
723 * If we're trying to assess whether it's OK to do a free,
724 * cut the reservation in half to allow forward progress
725 * (e.g. make it possible to rm(1) files from a full pool).
726 */
727 space = spa_get_dspace(dp->dp_spa);
728 resv = spa_get_slop_space(dp->dp_spa);
729 if (netfree)
730 resv >>= 1;
731
732 return (space - resv);
733 }
734
735 boolean_t
736 dsl_pool_need_dirty_delay(dsl_pool_t *dp)
737 {
738 uint64_t delay_min_bytes =
739 zfs_dirty_data_max * zfs_delay_min_dirty_percent / 100;
740 boolean_t rv;
741
742 mutex_enter(&dp->dp_lock);
743 if (dp->dp_dirty_total > zfs_dirty_data_sync)
744 txg_kick(dp);
745 rv = (dp->dp_dirty_total > delay_min_bytes);
746 mutex_exit(&dp->dp_lock);
747 return (rv);
748 }
749
750 void
751 dsl_pool_dirty_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
752 {
753 if (space > 0) {
754 mutex_enter(&dp->dp_lock);
755 dp->dp_dirty_pertxg[tx->tx_txg & TXG_MASK] += space;
756 dsl_pool_dirty_delta(dp, space);
757 mutex_exit(&dp->dp_lock);
758 }
759 }
760
761 void
762 dsl_pool_undirty_space(dsl_pool_t *dp, int64_t space, uint64_t txg)
763 {
764 ASSERT3S(space, >=, 0);
765 if (space == 0)
766 return;
767 mutex_enter(&dp->dp_lock);
768 if (dp->dp_dirty_pertxg[txg & TXG_MASK] < space) {
769 /* XXX writing something we didn't dirty? */
770 space = dp->dp_dirty_pertxg[txg & TXG_MASK];
771 }
772 ASSERT3U(dp->dp_dirty_pertxg[txg & TXG_MASK], >=, space);
773 dp->dp_dirty_pertxg[txg & TXG_MASK] -= space;
774 ASSERT3U(dp->dp_dirty_total, >=, space);
775 dsl_pool_dirty_delta(dp, -space);
776 mutex_exit(&dp->dp_lock);
777 }
778
779 /* ARGSUSED */
780 static int
781 upgrade_clones_cb(dsl_pool_t *dp, dsl_dataset_t *hds, void *arg)
782 {
783 dmu_tx_t *tx = arg;
784 dsl_dataset_t *ds, *prev = NULL;
785 int err;
786
787 err = dsl_dataset_hold_obj(dp, hds->ds_object, FTAG, &ds);
788 if (err)
789 return (err);
790
791 while (dsl_dataset_phys(ds)->ds_prev_snap_obj != 0) {
792 err = dsl_dataset_hold_obj(dp,
793 dsl_dataset_phys(ds)->ds_prev_snap_obj, FTAG, &prev);
794 if (err) {
795 dsl_dataset_rele(ds, FTAG);
796 return (err);
797 }
798
799 if (dsl_dataset_phys(prev)->ds_next_snap_obj != ds->ds_object)
800 break;
801 dsl_dataset_rele(ds, FTAG);
802 ds = prev;
803 prev = NULL;
804 }
805
806 if (prev == NULL) {
807 prev = dp->dp_origin_snap;
808
809 /*
810 * The $ORIGIN can't have any data, or the accounting
811 * will be wrong.
812 */
813 rrw_enter(&ds->ds_bp_rwlock, RW_READER, FTAG);
814 ASSERT0(dsl_dataset_phys(prev)->ds_bp.blk_birth);
815 rrw_exit(&ds->ds_bp_rwlock, FTAG);
816
817 /* The origin doesn't get attached to itself */
818 if (ds->ds_object == prev->ds_object) {
819 dsl_dataset_rele(ds, FTAG);
820 return (0);
821 }
822
823 dmu_buf_will_dirty(ds->ds_dbuf, tx);
824 dsl_dataset_phys(ds)->ds_prev_snap_obj = prev->ds_object;
825 dsl_dataset_phys(ds)->ds_prev_snap_txg =
826 dsl_dataset_phys(prev)->ds_creation_txg;
827
828 dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
829 dsl_dir_phys(ds->ds_dir)->dd_origin_obj = prev->ds_object;
830
831 dmu_buf_will_dirty(prev->ds_dbuf, tx);
832 dsl_dataset_phys(prev)->ds_num_children++;
833
834 if (dsl_dataset_phys(ds)->ds_next_snap_obj == 0) {
835 ASSERT(ds->ds_prev == NULL);
836 VERIFY0(dsl_dataset_hold_obj(dp,
837 dsl_dataset_phys(ds)->ds_prev_snap_obj,
838 ds, &ds->ds_prev));
839 }
840 }
841
842 ASSERT3U(dsl_dir_phys(ds->ds_dir)->dd_origin_obj, ==, prev->ds_object);
843 ASSERT3U(dsl_dataset_phys(ds)->ds_prev_snap_obj, ==, prev->ds_object);
844
845 if (dsl_dataset_phys(prev)->ds_next_clones_obj == 0) {
846 dmu_buf_will_dirty(prev->ds_dbuf, tx);
847 dsl_dataset_phys(prev)->ds_next_clones_obj =
848 zap_create(dp->dp_meta_objset,
849 DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
850 }
851 VERIFY0(zap_add_int(dp->dp_meta_objset,
852 dsl_dataset_phys(prev)->ds_next_clones_obj, ds->ds_object, tx));
853
854 dsl_dataset_rele(ds, FTAG);
855 if (prev != dp->dp_origin_snap)
856 dsl_dataset_rele(prev, FTAG);
857 return (0);
858 }
859
860 void
861 dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx)
862 {
863 ASSERT(dmu_tx_is_syncing(tx));
864 ASSERT(dp->dp_origin_snap != NULL);
865
866 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj, upgrade_clones_cb,
867 tx, DS_FIND_CHILDREN | DS_FIND_SERIALIZE));
868 }
869
870 /* ARGSUSED */
871 static int
872 upgrade_dir_clones_cb(dsl_pool_t *dp, dsl_dataset_t *ds, void *arg)
873 {
874 dmu_tx_t *tx = arg;
875 objset_t *mos = dp->dp_meta_objset;
876
877 if (dsl_dir_phys(ds->ds_dir)->dd_origin_obj != 0) {
878 dsl_dataset_t *origin;
879
880 VERIFY0(dsl_dataset_hold_obj(dp,
881 dsl_dir_phys(ds->ds_dir)->dd_origin_obj, FTAG, &origin));
882
883 if (dsl_dir_phys(origin->ds_dir)->dd_clones == 0) {
884 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
885 dsl_dir_phys(origin->ds_dir)->dd_clones =
886 zap_create(mos, DMU_OT_DSL_CLONES, DMU_OT_NONE,
887 0, tx);
888 }
889
890 VERIFY0(zap_add_int(dp->dp_meta_objset,
891 dsl_dir_phys(origin->ds_dir)->dd_clones,
892 ds->ds_object, tx));
893
894 dsl_dataset_rele(origin, FTAG);
895 }
896 return (0);
897 }
898
899 void
900 dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx)
901 {
902 ASSERT(dmu_tx_is_syncing(tx));
903 uint64_t obj;
904
905 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx);
906 VERIFY0(dsl_pool_open_special_dir(dp,
907 FREE_DIR_NAME, &dp->dp_free_dir));
908
909 /*
910 * We can't use bpobj_alloc(), because spa_version() still
911 * returns the old version, and we need a new-version bpobj with
912 * subobj support. So call dmu_object_alloc() directly.
913 */
914 obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ,
915 SPA_OLD_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx);
916 VERIFY0(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
917 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
918 VERIFY0(bpobj_open(&dp->dp_free_bpobj, dp->dp_meta_objset, obj));
919
920 VERIFY0(dmu_objset_find_dp(dp, dp->dp_root_dir_obj,
921 upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN | DS_FIND_SERIALIZE));
922 }
923
924 void
925 dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
926 {
927 uint64_t dsobj;
928 dsl_dataset_t *ds;
929
930 ASSERT(dmu_tx_is_syncing(tx));
931 ASSERT(dp->dp_origin_snap == NULL);
932 ASSERT(rrw_held(&dp->dp_config_rwlock, RW_WRITER));
933
934 /* create the origin dir, ds, & snap-ds */
935 dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME,
936 NULL, 0, kcred, tx);
937 VERIFY0(dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
938 dsl_dataset_snapshot_sync_impl(ds, ORIGIN_DIR_NAME, tx);
939 VERIFY0(dsl_dataset_hold_obj(dp, dsl_dataset_phys(ds)->ds_prev_snap_obj,
940 dp, &dp->dp_origin_snap));
941 dsl_dataset_rele(ds, FTAG);
942 }
943
944 taskq_t *
945 dsl_pool_vnrele_taskq(dsl_pool_t *dp)
946 {
947 return (dp->dp_vnrele_taskq);
948 }
949
950 /*
951 * Walk through the pool-wide zap object of temporary snapshot user holds
952 * and release them.
953 */
954 void
955 dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp)
956 {
957 zap_attribute_t za;
958 zap_cursor_t zc;
959 objset_t *mos = dp->dp_meta_objset;
960 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
961 nvlist_t *holds;
962
963 if (zapobj == 0)
964 return;
965 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
966
967 holds = fnvlist_alloc();
968
969 for (zap_cursor_init(&zc, mos, zapobj);
970 zap_cursor_retrieve(&zc, &za) == 0;
971 zap_cursor_advance(&zc)) {
972 char *htag;
973 nvlist_t *tags;
974
975 htag = strchr(za.za_name, '-');
976 *htag = '\0';
977 ++htag;
978 if (nvlist_lookup_nvlist(holds, za.za_name, &tags) != 0) {
979 tags = fnvlist_alloc();
980 fnvlist_add_boolean(tags, htag);
981 fnvlist_add_nvlist(holds, za.za_name, tags);
982 fnvlist_free(tags);
983 } else {
984 fnvlist_add_boolean(tags, htag);
985 }
986 }
987 dsl_dataset_user_release_tmp(dp, holds);
988 fnvlist_free(holds);
989 zap_cursor_fini(&zc);
990 }
991
992 /*
993 * Create the pool-wide zap object for storing temporary snapshot holds.
994 */
995 void
996 dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx)
997 {
998 objset_t *mos = dp->dp_meta_objset;
999
1000 ASSERT(dp->dp_tmp_userrefs_obj == 0);
1001 ASSERT(dmu_tx_is_syncing(tx));
1002
1003 dp->dp_tmp_userrefs_obj = zap_create_link(mos, DMU_OT_USERREFS,
1004 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS, tx);
1005 }
1006
1007 static int
1008 dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj,
1009 const char *tag, uint64_t now, dmu_tx_t *tx, boolean_t holding)
1010 {
1011 objset_t *mos = dp->dp_meta_objset;
1012 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
1013 char *name;
1014 int error;
1015
1016 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
1017 ASSERT(dmu_tx_is_syncing(tx));
1018
1019 /*
1020 * If the pool was created prior to SPA_VERSION_USERREFS, the
1021 * zap object for temporary holds might not exist yet.
1022 */
1023 if (zapobj == 0) {
1024 if (holding) {
1025 dsl_pool_user_hold_create_obj(dp, tx);
1026 zapobj = dp->dp_tmp_userrefs_obj;
1027 } else {
1028 return (SET_ERROR(ENOENT));
1029 }
1030 }
1031
1032 name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag);
1033 if (holding)
1034 error = zap_add(mos, zapobj, name, 8, 1, &now, tx);
1035 else
1036 error = zap_remove(mos, zapobj, name, tx);
1037 strfree(name);
1038
1039 return (error);
1040 }
1041
1042 /*
1043 * Add a temporary hold for the given dataset object and tag.
1044 */
1045 int
1046 dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1047 uint64_t now, dmu_tx_t *tx)
1048 {
1049 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE));
1050 }
1051
1052 /*
1053 * Release a temporary hold for the given dataset object and tag.
1054 */
1055 int
1056 dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1057 dmu_tx_t *tx)
1058 {
1059 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, NULL,
1060 tx, B_FALSE));
1061 }
1062
1063 /*
1064 * DSL Pool Configuration Lock
1065 *
1066 * The dp_config_rwlock protects against changes to DSL state (e.g. dataset
1067 * creation / destruction / rename / property setting). It must be held for
1068 * read to hold a dataset or dsl_dir. I.e. you must call
1069 * dsl_pool_config_enter() or dsl_pool_hold() before calling
1070 * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock
1071 * must be held continuously until all datasets and dsl_dirs are released.
1072 *
1073 * The only exception to this rule is that if a "long hold" is placed on
1074 * a dataset, then the dp_config_rwlock may be dropped while the dataset
1075 * is still held. The long hold will prevent the dataset from being
1076 * destroyed -- the destroy will fail with EBUSY. A long hold can be
1077 * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset
1078 * (by calling dsl_{dataset,objset}_{try}own{_obj}).
1079 *
1080 * Legitimate long-holders (including owners) should be long-running, cancelable
1081 * tasks that should cause "zfs destroy" to fail. This includes DMU
1082 * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open),
1083 * "zfs send", and "zfs diff". There are several other long-holders whose
1084 * uses are suboptimal (e.g. "zfs promote", and zil_suspend()).
1085 *
1086 * The usual formula for long-holding would be:
1087 * dsl_pool_hold()
1088 * dsl_dataset_hold()
1089 * ... perform checks ...
1090 * dsl_dataset_long_hold()
1091 * dsl_pool_rele()
1092 * ... perform long-running task ...
1093 * dsl_dataset_long_rele()
1094 * dsl_dataset_rele()
1095 *
1096 * Note that when the long hold is released, the dataset is still held but
1097 * the pool is not held. The dataset may change arbitrarily during this time
1098 * (e.g. it could be destroyed). Therefore you shouldn't do anything to the
1099 * dataset except release it.
1100 *
1101 * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only
1102 * or modifying operations.
1103 *
1104 * Modifying operations should generally use dsl_sync_task(). The synctask
1105 * infrastructure enforces proper locking strategy with respect to the
1106 * dp_config_rwlock. See the comment above dsl_sync_task() for details.
1107 *
1108 * Read-only operations will manually hold the pool, then the dataset, obtain
1109 * information from the dataset, then release the pool and dataset.
1110 * dmu_objset_{hold,rele}() are convenience routines that also do the pool
1111 * hold/rele.
1112 */
1113
1114 int
1115 dsl_pool_hold(const char *name, void *tag, dsl_pool_t **dp)
1116 {
1117 spa_t *spa;
1118 int error;
1119
1120 error = spa_open(name, &spa, tag);
1121 if (error == 0) {
1122 *dp = spa_get_dsl(spa);
1123 dsl_pool_config_enter(*dp, tag);
1124 }
1125 return (error);
1126 }
1127
1128 void
1129 dsl_pool_rele(dsl_pool_t *dp, void *tag)
1130 {
1131 dsl_pool_config_exit(dp, tag);
1132 spa_close(dp->dp_spa, tag);
1133 }
1134
1135 void
1136 dsl_pool_config_enter(dsl_pool_t *dp, void *tag)
1137 {
1138 /*
1139 * We use a "reentrant" reader-writer lock, but not reentrantly.
1140 *
1141 * The rrwlock can (with the track_all flag) track all reading threads,
1142 * which is very useful for debugging which code path failed to release
1143 * the lock, and for verifying that the *current* thread does hold
1144 * the lock.
1145 *
1146 * (Unlike a rwlock, which knows that N threads hold it for
1147 * read, but not *which* threads, so rw_held(RW_READER) returns TRUE
1148 * if any thread holds it for read, even if this thread doesn't).
1149 */
1150 ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER));
1151 rrw_enter(&dp->dp_config_rwlock, RW_READER, tag);
1152 }
1153
1154 void
1155 dsl_pool_config_enter_prio(dsl_pool_t *dp, void *tag)
1156 {
1157 ASSERT(!rrw_held(&dp->dp_config_rwlock, RW_READER));
1158 rrw_enter_read_prio(&dp->dp_config_rwlock, tag);
1159 }
1160
1161 void
1162 dsl_pool_config_exit(dsl_pool_t *dp, void *tag)
1163 {
1164 rrw_exit(&dp->dp_config_rwlock, tag);
1165 }
1166
1167 boolean_t
1168 dsl_pool_config_held(dsl_pool_t *dp)
1169 {
1170 return (RRW_LOCK_HELD(&dp->dp_config_rwlock));
1171 }
1172
1173 boolean_t
1174 dsl_pool_config_held_writer(dsl_pool_t *dp)
1175 {
1176 return (RRW_WRITE_HELD(&dp->dp_config_rwlock));
1177 }