4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 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 2016 Nexenta Systems, Inc. All rights reserved.
29 #include <sys/dsl_pool.h>
30 #include <sys/dsl_dataset.h>
31 #include <sys/dsl_prop.h>
32 #include <sys/dsl_dir.h>
33 #include <sys/dsl_synctask.h>
34 #include <sys/dsl_scan.h>
35 #include <sys/dnode.h>
36 #include <sys/dmu_tx.h>
37 #include <sys/dmu_objset.h>
41 #include <sys/zfs_context.h>
42 #include <sys/fs/zfs.h>
43 #include <sys/zfs_znode.h>
44 #include <sys/spa_impl.h>
45 #include <sys/dsl_deadlist.h>
46 #include <sys/bptree.h>
47 #include <sys/zfeature.h>
48 #include <sys/zil_impl.h>
49 #include <sys/dsl_userhold.h>
50 #include <sys/trace_txg.h>
57 * ZFS must limit the rate of incoming writes to the rate at which it is able
58 * to sync data modifications to the backend storage. Throttling by too much
59 * creates an artificial limit; throttling by too little can only be sustained
60 * for short periods and would lead to highly lumpy performance. On a per-pool
61 * basis, ZFS tracks the amount of modified (dirty) data. As operations change
62 * data, the amount of dirty data increases; as ZFS syncs out data, the amount
63 * of dirty data decreases. When the amount of dirty data exceeds a
64 * predetermined threshold further modifications are blocked until the amount
65 * of dirty data decreases (as data is synced out).
67 * The limit on dirty data is tunable, and should be adjusted according to
68 * both the IO capacity and available memory of the system. The larger the
69 * window, the more ZFS is able to aggregate and amortize metadata (and data)
70 * changes. However, memory is a limited resource, and allowing for more dirty
71 * data comes at the cost of keeping other useful data in memory (for example
72 * ZFS data cached by the ARC).
76 * As buffers are modified dsl_pool_willuse_space() increments both the per-
77 * txg (dp_dirty_pertxg[]) and poolwide (dp_dirty_total) accounting of
78 * dirty space used; dsl_pool_dirty_space() decrements those values as data
79 * is synced out from dsl_pool_sync(). While only the poolwide value is
80 * relevant, the per-txg value is useful for debugging. The tunable
81 * zfs_dirty_data_max determines the dirty space limit. Once that value is
82 * exceeded, new writes are halted until space frees up.
84 * The zfs_dirty_data_sync tunable dictates the threshold at which we
85 * ensure that there is a txg syncing (see the comment in txg.c for a full
86 * description of transaction group stages).
88 * The IO scheduler uses both the dirty space limit and current amount of
89 * dirty data as inputs. Those values affect the number of concurrent IOs ZFS
90 * issues. See the comment in vdev_queue.c for details of the IO scheduler.
92 * The delay is also calculated based on the amount of dirty data. See the
93 * comment above dmu_tx_delay() for details.
97 * zfs_dirty_data_max will be set to zfs_dirty_data_max_percent% of all memory,
98 * capped at zfs_dirty_data_max_max. It can also be overridden with a module
101 unsigned long zfs_dirty_data_max
= 0;
102 unsigned long zfs_dirty_data_max_max
= 0;
103 int zfs_dirty_data_max_percent
= 10;
104 int zfs_dirty_data_max_max_percent
= 25;
107 * If there is at least this much dirty data, push out a txg.
109 unsigned long zfs_dirty_data_sync
= 64 * 1024 * 1024;
112 * Once there is this amount of dirty data, the dmu_tx_delay() will kick in
113 * and delay each transaction.
114 * This value should be >= zfs_vdev_async_write_active_max_dirty_percent.
116 int zfs_delay_min_dirty_percent
= 60;
119 * This controls how quickly the delay approaches infinity.
120 * Larger values cause it to delay more for a given amount of dirty data.
121 * Therefore larger values will cause there to be less dirty data for a
124 * For the smoothest delay, this value should be about 1 billion divided
125 * by the maximum number of operations per second. This will smoothly
126 * handle between 10x and 1/10th this number.
128 * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the
129 * multiply in dmu_tx_delay().
131 unsigned long zfs_delay_scale
= 1000 * 1000 * 1000 / 2000;
134 * This determines the number of threads used by the dp_sync_taskq.
136 int zfs_sync_taskq_batch_pct
= 75;
139 dsl_pool_open_special_dir(dsl_pool_t
*dp
, const char *name
, dsl_dir_t
**ddp
)
144 err
= zap_lookup(dp
->dp_meta_objset
,
145 dsl_dir_phys(dp
->dp_root_dir
)->dd_child_dir_zapobj
,
146 name
, sizeof (obj
), 1, &obj
);
150 return (dsl_dir_hold_obj(dp
, obj
, name
, dp
, ddp
));
154 dsl_pool_open_impl(spa_t
*spa
, uint64_t txg
)
157 blkptr_t
*bp
= spa_get_rootblkptr(spa
);
159 dp
= kmem_zalloc(sizeof (dsl_pool_t
), KM_SLEEP
);
161 dp
->dp_meta_rootbp
= *bp
;
162 rrw_init(&dp
->dp_config_rwlock
, B_TRUE
);
166 txg_list_create(&dp
->dp_dirty_datasets
, spa
,
167 offsetof(dsl_dataset_t
, ds_dirty_link
));
168 txg_list_create(&dp
->dp_dirty_zilogs
, spa
,
169 offsetof(zilog_t
, zl_dirty_link
));
170 txg_list_create(&dp
->dp_dirty_dirs
, spa
,
171 offsetof(dsl_dir_t
, dd_dirty_link
));
172 txg_list_create(&dp
->dp_sync_tasks
, spa
,
173 offsetof(dsl_sync_task_t
, dst_node
));
175 dp
->dp_sync_taskq
= taskq_create("dp_sync_taskq",
176 zfs_sync_taskq_batch_pct
, minclsyspri
, 1, INT_MAX
,
177 TASKQ_THREADS_CPU_PCT
);
179 mutex_init(&dp
->dp_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
180 cv_init(&dp
->dp_spaceavail_cv
, NULL
, CV_DEFAULT
, NULL
);
182 dp
->dp_iput_taskq
= taskq_create("z_iput", max_ncpus
, defclsyspri
,
183 max_ncpus
* 8, INT_MAX
, TASKQ_PREPOPULATE
| TASKQ_DYNAMIC
);
189 dsl_pool_init(spa_t
*spa
, uint64_t txg
, dsl_pool_t
**dpp
)
192 dsl_pool_t
*dp
= dsl_pool_open_impl(spa
, txg
);
195 * Initialize the caller's dsl_pool_t structure before we actually open
196 * the meta objset. This is done because a self-healing write zio may
197 * be issued as part of dmu_objset_open_impl() and the spa needs its
198 * dsl_pool_t initialized in order to handle the write.
202 err
= dmu_objset_open_impl(spa
, NULL
, &dp
->dp_meta_rootbp
,
203 &dp
->dp_meta_objset
);
213 dsl_pool_open(dsl_pool_t
*dp
)
220 rrw_enter(&dp
->dp_config_rwlock
, RW_WRITER
, FTAG
);
221 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
222 DMU_POOL_ROOT_DATASET
, sizeof (uint64_t), 1,
223 &dp
->dp_root_dir_obj
);
227 err
= dsl_dir_hold_obj(dp
, dp
->dp_root_dir_obj
,
228 NULL
, dp
, &dp
->dp_root_dir
);
232 err
= dsl_pool_open_special_dir(dp
, MOS_DIR_NAME
, &dp
->dp_mos_dir
);
236 if (spa_version(dp
->dp_spa
) >= SPA_VERSION_ORIGIN
) {
237 err
= dsl_pool_open_special_dir(dp
, ORIGIN_DIR_NAME
, &dd
);
240 err
= dsl_dataset_hold_obj(dp
,
241 dsl_dir_phys(dd
)->dd_head_dataset_obj
, FTAG
, &ds
);
243 err
= dsl_dataset_hold_obj(dp
,
244 dsl_dataset_phys(ds
)->ds_prev_snap_obj
, dp
,
245 &dp
->dp_origin_snap
);
246 dsl_dataset_rele(ds
, FTAG
);
248 dsl_dir_rele(dd
, dp
);
253 if (spa_version(dp
->dp_spa
) >= SPA_VERSION_DEADLISTS
) {
254 err
= dsl_pool_open_special_dir(dp
, FREE_DIR_NAME
,
259 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
260 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
);
263 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
,
264 dp
->dp_meta_objset
, obj
));
268 * Note: errors ignored, because the leak dir will not exist if we
269 * have not encountered a leak yet.
271 (void) dsl_pool_open_special_dir(dp
, LEAK_DIR_NAME
,
274 if (spa_feature_is_active(dp
->dp_spa
, SPA_FEATURE_ASYNC_DESTROY
)) {
275 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
276 DMU_POOL_BPTREE_OBJ
, sizeof (uint64_t), 1,
282 if (spa_feature_is_active(dp
->dp_spa
, SPA_FEATURE_EMPTY_BPOBJ
)) {
283 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
284 DMU_POOL_EMPTY_BPOBJ
, sizeof (uint64_t), 1,
285 &dp
->dp_empty_bpobj
);
290 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
291 DMU_POOL_TMP_USERREFS
, sizeof (uint64_t), 1,
292 &dp
->dp_tmp_userrefs_obj
);
298 err
= dsl_scan_init(dp
, dp
->dp_tx
.tx_open_txg
);
301 rrw_exit(&dp
->dp_config_rwlock
, FTAG
);
306 dsl_pool_close(dsl_pool_t
*dp
)
309 * Drop our references from dsl_pool_open().
311 * Since we held the origin_snap from "syncing" context (which
312 * includes pool-opening context), it actually only got a "ref"
313 * and not a hold, so just drop that here.
315 if (dp
->dp_origin_snap
)
316 dsl_dataset_rele(dp
->dp_origin_snap
, dp
);
318 dsl_dir_rele(dp
->dp_mos_dir
, dp
);
320 dsl_dir_rele(dp
->dp_free_dir
, dp
);
322 dsl_dir_rele(dp
->dp_leak_dir
, dp
);
324 dsl_dir_rele(dp
->dp_root_dir
, dp
);
326 bpobj_close(&dp
->dp_free_bpobj
);
328 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
329 if (dp
->dp_meta_objset
)
330 dmu_objset_evict(dp
->dp_meta_objset
);
332 txg_list_destroy(&dp
->dp_dirty_datasets
);
333 txg_list_destroy(&dp
->dp_dirty_zilogs
);
334 txg_list_destroy(&dp
->dp_sync_tasks
);
335 txg_list_destroy(&dp
->dp_dirty_dirs
);
337 taskq_destroy(dp
->dp_sync_taskq
);
340 * We can't set retry to TRUE since we're explicitly specifying
341 * a spa to flush. This is good enough; any missed buffers for
342 * this spa won't cause trouble, and they'll eventually fall
343 * out of the ARC just like any other unused buffer.
345 arc_flush(dp
->dp_spa
, FALSE
);
347 mmp_fini(dp
->dp_spa
);
350 dmu_buf_user_evict_wait();
352 rrw_destroy(&dp
->dp_config_rwlock
);
353 mutex_destroy(&dp
->dp_lock
);
354 cv_destroy(&dp
->dp_spaceavail_cv
);
355 taskq_destroy(dp
->dp_iput_taskq
);
357 vmem_free(dp
->dp_blkstats
, sizeof (zfs_all_blkstats_t
));
358 kmem_free(dp
, sizeof (dsl_pool_t
));
362 dsl_pool_create(spa_t
*spa
, nvlist_t
*zplprops
, dsl_crypto_params_t
*dcp
,
366 dsl_pool_t
*dp
= dsl_pool_open_impl(spa
, txg
);
367 dmu_tx_t
*tx
= dmu_tx_create_assigned(dp
, txg
);
372 rrw_enter(&dp
->dp_config_rwlock
, RW_WRITER
, FTAG
);
374 /* create and open the MOS (meta-objset) */
375 dp
->dp_meta_objset
= dmu_objset_create_impl(spa
,
376 NULL
, &dp
->dp_meta_rootbp
, DMU_OST_META
, tx
);
377 spa
->spa_meta_objset
= dp
->dp_meta_objset
;
379 /* create the pool directory */
380 err
= zap_create_claim(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
381 DMU_OT_OBJECT_DIRECTORY
, DMU_OT_NONE
, 0, tx
);
384 /* Initialize scan structures */
385 VERIFY0(dsl_scan_init(dp
, txg
));
387 /* create and open the root dir */
388 dp
->dp_root_dir_obj
= dsl_dir_create_sync(dp
, NULL
, NULL
, tx
);
389 VERIFY0(dsl_dir_hold_obj(dp
, dp
->dp_root_dir_obj
,
390 NULL
, dp
, &dp
->dp_root_dir
));
392 /* create and open the meta-objset dir */
393 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
, MOS_DIR_NAME
, tx
);
394 VERIFY0(dsl_pool_open_special_dir(dp
,
395 MOS_DIR_NAME
, &dp
->dp_mos_dir
));
397 if (spa_version(spa
) >= SPA_VERSION_DEADLISTS
) {
398 /* create and open the free dir */
399 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
,
401 VERIFY0(dsl_pool_open_special_dir(dp
,
402 FREE_DIR_NAME
, &dp
->dp_free_dir
));
404 /* create and open the free_bplist */
405 obj
= bpobj_alloc(dp
->dp_meta_objset
, SPA_OLD_MAXBLOCKSIZE
, tx
);
406 VERIFY(zap_add(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
407 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
, tx
) == 0);
408 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
,
409 dp
->dp_meta_objset
, obj
));
412 if (spa_version(spa
) >= SPA_VERSION_DSL_SCRUB
)
413 dsl_pool_create_origin(dp
, tx
);
416 * Some features may be needed when creating the root dataset, so we
417 * create the feature objects here.
419 if (spa_version(spa
) >= SPA_VERSION_FEATURES
)
420 spa_feature_create_zap_objects(spa
, tx
);
422 if (dcp
!= NULL
&& dcp
->cp_crypt
!= ZIO_CRYPT_OFF
&&
423 dcp
->cp_crypt
!= ZIO_CRYPT_INHERIT
)
424 spa_feature_enable(spa
, SPA_FEATURE_ENCRYPTION
, tx
);
426 /* create the root dataset */
427 obj
= dsl_dataset_create_sync_dd(dp
->dp_root_dir
, NULL
, dcp
, 0, tx
);
429 /* create the root objset */
430 VERIFY0(dsl_dataset_hold_obj(dp
, obj
, FTAG
, &ds
));
431 rrw_enter(&ds
->ds_bp_rwlock
, RW_READER
, FTAG
);
432 VERIFY(NULL
!= (os
= dmu_objset_create_impl(dp
->dp_spa
, ds
,
433 dsl_dataset_get_blkptr(ds
), DMU_OST_ZFS
, tx
)));
434 rrw_exit(&ds
->ds_bp_rwlock
, FTAG
);
436 zfs_create_fs(os
, kcred
, zplprops
, tx
);
438 dsl_dataset_rele(ds
, FTAG
);
442 rrw_exit(&dp
->dp_config_rwlock
, FTAG
);
448 * Account for the meta-objset space in its placeholder dsl_dir.
451 dsl_pool_mos_diduse_space(dsl_pool_t
*dp
,
452 int64_t used
, int64_t comp
, int64_t uncomp
)
454 ASSERT3U(comp
, ==, uncomp
); /* it's all metadata */
455 mutex_enter(&dp
->dp_lock
);
456 dp
->dp_mos_used_delta
+= used
;
457 dp
->dp_mos_compressed_delta
+= comp
;
458 dp
->dp_mos_uncompressed_delta
+= uncomp
;
459 mutex_exit(&dp
->dp_lock
);
463 dsl_pool_sync_mos(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
465 zio_t
*zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
466 dmu_objset_sync(dp
->dp_meta_objset
, zio
, tx
);
467 VERIFY0(zio_wait(zio
));
468 dprintf_bp(&dp
->dp_meta_rootbp
, "meta objset rootbp is %s", "");
469 spa_set_rootblkptr(dp
->dp_spa
, &dp
->dp_meta_rootbp
);
473 dsl_pool_dirty_delta(dsl_pool_t
*dp
, int64_t delta
)
475 ASSERT(MUTEX_HELD(&dp
->dp_lock
));
478 ASSERT3U(-delta
, <=, dp
->dp_dirty_total
);
480 dp
->dp_dirty_total
+= delta
;
483 * Note: we signal even when increasing dp_dirty_total.
484 * This ensures forward progress -- each thread wakes the next waiter.
486 if (dp
->dp_dirty_total
< zfs_dirty_data_max
)
487 cv_signal(&dp
->dp_spaceavail_cv
);
491 dsl_pool_sync(dsl_pool_t
*dp
, uint64_t txg
)
497 objset_t
*mos
= dp
->dp_meta_objset
;
498 list_t synced_datasets
;
500 list_create(&synced_datasets
, sizeof (dsl_dataset_t
),
501 offsetof(dsl_dataset_t
, ds_synced_link
));
503 tx
= dmu_tx_create_assigned(dp
, txg
);
506 * Write out all dirty blocks of dirty datasets.
508 zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
509 while ((ds
= txg_list_remove(&dp
->dp_dirty_datasets
, txg
)) != NULL
) {
511 * We must not sync any non-MOS datasets twice, because
512 * we may have taken a snapshot of them. However, we
513 * may sync newly-created datasets on pass 2.
515 ASSERT(!list_link_active(&ds
->ds_synced_link
));
516 list_insert_tail(&synced_datasets
, ds
);
517 dsl_dataset_sync(ds
, zio
, tx
);
519 VERIFY0(zio_wait(zio
));
522 * We have written all of the accounted dirty data, so our
523 * dp_space_towrite should now be zero. However, some seldom-used
524 * code paths do not adhere to this (e.g. dbuf_undirty(), also
525 * rounding error in dbuf_write_physdone).
526 * Shore up the accounting of any dirtied space now.
528 dsl_pool_undirty_space(dp
, dp
->dp_dirty_pertxg
[txg
& TXG_MASK
], txg
);
531 * Update the long range free counter after
532 * we're done syncing user data
534 mutex_enter(&dp
->dp_lock
);
535 ASSERT(spa_sync_pass(dp
->dp_spa
) == 1 ||
536 dp
->dp_long_free_dirty_pertxg
[txg
& TXG_MASK
] == 0);
537 dp
->dp_long_free_dirty_pertxg
[txg
& TXG_MASK
] = 0;
538 mutex_exit(&dp
->dp_lock
);
541 * After the data blocks have been written (ensured by the zio_wait()
542 * above), update the user/group space accounting. This happens
543 * in tasks dispatched to dp_sync_taskq, so wait for them before
546 for (ds
= list_head(&synced_datasets
); ds
!= NULL
;
547 ds
= list_next(&synced_datasets
, ds
)) {
548 dmu_objset_do_userquota_updates(ds
->ds_objset
, tx
);
550 taskq_wait(dp
->dp_sync_taskq
);
553 * Sync the datasets again to push out the changes due to
554 * userspace updates. This must be done before we process the
555 * sync tasks, so that any snapshots will have the correct
556 * user accounting information (and we won't get confused
557 * about which blocks are part of the snapshot).
559 zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
560 while ((ds
= txg_list_remove(&dp
->dp_dirty_datasets
, txg
)) != NULL
) {
561 ASSERT(list_link_active(&ds
->ds_synced_link
));
562 dmu_buf_rele(ds
->ds_dbuf
, ds
);
563 dsl_dataset_sync(ds
, zio
, tx
);
565 VERIFY0(zio_wait(zio
));
568 * Now that the datasets have been completely synced, we can
569 * clean up our in-memory structures accumulated while syncing:
571 * - move dead blocks from the pending deadlist to the on-disk deadlist
572 * - release hold from dsl_dataset_dirty()
574 while ((ds
= list_remove_head(&synced_datasets
)) != NULL
) {
575 dsl_dataset_sync_done(ds
, tx
);
578 while ((dd
= txg_list_remove(&dp
->dp_dirty_dirs
, txg
)) != NULL
) {
579 dsl_dir_sync(dd
, tx
);
583 * The MOS's space is accounted for in the pool/$MOS
584 * (dp_mos_dir). We can't modify the mos while we're syncing
585 * it, so we remember the deltas and apply them here.
587 if (dp
->dp_mos_used_delta
!= 0 || dp
->dp_mos_compressed_delta
!= 0 ||
588 dp
->dp_mos_uncompressed_delta
!= 0) {
589 dsl_dir_diduse_space(dp
->dp_mos_dir
, DD_USED_HEAD
,
590 dp
->dp_mos_used_delta
,
591 dp
->dp_mos_compressed_delta
,
592 dp
->dp_mos_uncompressed_delta
, tx
);
593 dp
->dp_mos_used_delta
= 0;
594 dp
->dp_mos_compressed_delta
= 0;
595 dp
->dp_mos_uncompressed_delta
= 0;
598 if (!multilist_is_empty(mos
->os_dirty_dnodes
[txg
& TXG_MASK
])) {
599 dsl_pool_sync_mos(dp
, tx
);
603 * If we modify a dataset in the same txg that we want to destroy it,
604 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
605 * dsl_dir_destroy_check() will fail if there are unexpected holds.
606 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
607 * and clearing the hold on it) before we process the sync_tasks.
608 * The MOS data dirtied by the sync_tasks will be synced on the next
611 if (!txg_list_empty(&dp
->dp_sync_tasks
, txg
)) {
612 dsl_sync_task_t
*dst
;
614 * No more sync tasks should have been added while we
617 ASSERT3U(spa_sync_pass(dp
->dp_spa
), ==, 1);
618 while ((dst
= txg_list_remove(&dp
->dp_sync_tasks
, txg
)) != NULL
)
619 dsl_sync_task_sync(dst
, tx
);
624 DTRACE_PROBE2(dsl_pool_sync__done
, dsl_pool_t
*dp
, dp
, uint64_t, txg
);
628 dsl_pool_sync_done(dsl_pool_t
*dp
, uint64_t txg
)
632 while ((zilog
= txg_list_head(&dp
->dp_dirty_zilogs
, txg
))) {
633 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
635 * We don't remove the zilog from the dp_dirty_zilogs
636 * list until after we've cleaned it. This ensures that
637 * callers of zilog_is_dirty() receive an accurate
638 * answer when they are racing with the spa sync thread.
640 zil_clean(zilog
, txg
);
641 (void) txg_list_remove_this(&dp
->dp_dirty_zilogs
, zilog
, txg
);
642 ASSERT(!dmu_objset_is_dirty(zilog
->zl_os
, txg
));
643 dmu_buf_rele(ds
->ds_dbuf
, zilog
);
645 ASSERT(!dmu_objset_is_dirty(dp
->dp_meta_objset
, txg
));
649 * TRUE if the current thread is the tx_sync_thread or if we
650 * are being called from SPA context during pool initialization.
653 dsl_pool_sync_context(dsl_pool_t
*dp
)
655 return (curthread
== dp
->dp_tx
.tx_sync_thread
||
656 spa_is_initializing(dp
->dp_spa
) ||
657 taskq_member(dp
->dp_sync_taskq
, curthread
));
661 dsl_pool_adjustedsize(dsl_pool_t
*dp
, boolean_t netfree
)
663 uint64_t space
, resv
;
666 * If we're trying to assess whether it's OK to do a free,
667 * cut the reservation in half to allow forward progress
668 * (e.g. make it possible to rm(1) files from a full pool).
670 space
= spa_get_dspace(dp
->dp_spa
);
671 resv
= spa_get_slop_space(dp
->dp_spa
);
675 return (space
- resv
);
679 dsl_pool_need_dirty_delay(dsl_pool_t
*dp
)
681 uint64_t delay_min_bytes
=
682 zfs_dirty_data_max
* zfs_delay_min_dirty_percent
/ 100;
685 mutex_enter(&dp
->dp_lock
);
686 if (dp
->dp_dirty_total
> zfs_dirty_data_sync
)
688 rv
= (dp
->dp_dirty_total
> delay_min_bytes
);
689 mutex_exit(&dp
->dp_lock
);
694 dsl_pool_dirty_space(dsl_pool_t
*dp
, int64_t space
, dmu_tx_t
*tx
)
697 mutex_enter(&dp
->dp_lock
);
698 dp
->dp_dirty_pertxg
[tx
->tx_txg
& TXG_MASK
] += space
;
699 dsl_pool_dirty_delta(dp
, space
);
700 mutex_exit(&dp
->dp_lock
);
705 dsl_pool_undirty_space(dsl_pool_t
*dp
, int64_t space
, uint64_t txg
)
707 ASSERT3S(space
, >=, 0);
711 mutex_enter(&dp
->dp_lock
);
712 if (dp
->dp_dirty_pertxg
[txg
& TXG_MASK
] < space
) {
713 /* XXX writing something we didn't dirty? */
714 space
= dp
->dp_dirty_pertxg
[txg
& TXG_MASK
];
716 ASSERT3U(dp
->dp_dirty_pertxg
[txg
& TXG_MASK
], >=, space
);
717 dp
->dp_dirty_pertxg
[txg
& TXG_MASK
] -= space
;
718 ASSERT3U(dp
->dp_dirty_total
, >=, space
);
719 dsl_pool_dirty_delta(dp
, -space
);
720 mutex_exit(&dp
->dp_lock
);
725 upgrade_clones_cb(dsl_pool_t
*dp
, dsl_dataset_t
*hds
, void *arg
)
728 dsl_dataset_t
*ds
, *prev
= NULL
;
731 err
= dsl_dataset_hold_obj(dp
, hds
->ds_object
, FTAG
, &ds
);
735 while (dsl_dataset_phys(ds
)->ds_prev_snap_obj
!= 0) {
736 err
= dsl_dataset_hold_obj(dp
,
737 dsl_dataset_phys(ds
)->ds_prev_snap_obj
, FTAG
, &prev
);
739 dsl_dataset_rele(ds
, FTAG
);
743 if (dsl_dataset_phys(prev
)->ds_next_snap_obj
!= ds
->ds_object
)
745 dsl_dataset_rele(ds
, FTAG
);
751 prev
= dp
->dp_origin_snap
;
754 * The $ORIGIN can't have any data, or the accounting
757 rrw_enter(&ds
->ds_bp_rwlock
, RW_READER
, FTAG
);
758 ASSERT0(dsl_dataset_phys(prev
)->ds_bp
.blk_birth
);
759 rrw_exit(&ds
->ds_bp_rwlock
, FTAG
);
761 /* The origin doesn't get attached to itself */
762 if (ds
->ds_object
== prev
->ds_object
) {
763 dsl_dataset_rele(ds
, FTAG
);
767 dmu_buf_will_dirty(ds
->ds_dbuf
, tx
);
768 dsl_dataset_phys(ds
)->ds_prev_snap_obj
= prev
->ds_object
;
769 dsl_dataset_phys(ds
)->ds_prev_snap_txg
=
770 dsl_dataset_phys(prev
)->ds_creation_txg
;
772 dmu_buf_will_dirty(ds
->ds_dir
->dd_dbuf
, tx
);
773 dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
= prev
->ds_object
;
775 dmu_buf_will_dirty(prev
->ds_dbuf
, tx
);
776 dsl_dataset_phys(prev
)->ds_num_children
++;
778 if (dsl_dataset_phys(ds
)->ds_next_snap_obj
== 0) {
779 ASSERT(ds
->ds_prev
== NULL
);
780 VERIFY0(dsl_dataset_hold_obj(dp
,
781 dsl_dataset_phys(ds
)->ds_prev_snap_obj
,
786 ASSERT3U(dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
, ==, prev
->ds_object
);
787 ASSERT3U(dsl_dataset_phys(ds
)->ds_prev_snap_obj
, ==, prev
->ds_object
);
789 if (dsl_dataset_phys(prev
)->ds_next_clones_obj
== 0) {
790 dmu_buf_will_dirty(prev
->ds_dbuf
, tx
);
791 dsl_dataset_phys(prev
)->ds_next_clones_obj
=
792 zap_create(dp
->dp_meta_objset
,
793 DMU_OT_NEXT_CLONES
, DMU_OT_NONE
, 0, tx
);
795 VERIFY0(zap_add_int(dp
->dp_meta_objset
,
796 dsl_dataset_phys(prev
)->ds_next_clones_obj
, ds
->ds_object
, tx
));
798 dsl_dataset_rele(ds
, FTAG
);
799 if (prev
!= dp
->dp_origin_snap
)
800 dsl_dataset_rele(prev
, FTAG
);
805 dsl_pool_upgrade_clones(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
807 ASSERT(dmu_tx_is_syncing(tx
));
808 ASSERT(dp
->dp_origin_snap
!= NULL
);
810 VERIFY0(dmu_objset_find_dp(dp
, dp
->dp_root_dir_obj
, upgrade_clones_cb
,
811 tx
, DS_FIND_CHILDREN
| DS_FIND_SERIALIZE
));
816 upgrade_dir_clones_cb(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *arg
)
819 objset_t
*mos
= dp
->dp_meta_objset
;
821 if (dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
!= 0) {
822 dsl_dataset_t
*origin
;
824 VERIFY0(dsl_dataset_hold_obj(dp
,
825 dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
, FTAG
, &origin
));
827 if (dsl_dir_phys(origin
->ds_dir
)->dd_clones
== 0) {
828 dmu_buf_will_dirty(origin
->ds_dir
->dd_dbuf
, tx
);
829 dsl_dir_phys(origin
->ds_dir
)->dd_clones
=
830 zap_create(mos
, DMU_OT_DSL_CLONES
, DMU_OT_NONE
,
834 VERIFY0(zap_add_int(dp
->dp_meta_objset
,
835 dsl_dir_phys(origin
->ds_dir
)->dd_clones
,
838 dsl_dataset_rele(origin
, FTAG
);
844 dsl_pool_upgrade_dir_clones(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
848 ASSERT(dmu_tx_is_syncing(tx
));
850 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
, FREE_DIR_NAME
, tx
);
851 VERIFY0(dsl_pool_open_special_dir(dp
,
852 FREE_DIR_NAME
, &dp
->dp_free_dir
));
855 * We can't use bpobj_alloc(), because spa_version() still
856 * returns the old version, and we need a new-version bpobj with
857 * subobj support. So call dmu_object_alloc() directly.
859 obj
= dmu_object_alloc(dp
->dp_meta_objset
, DMU_OT_BPOBJ
,
860 SPA_OLD_MAXBLOCKSIZE
, DMU_OT_BPOBJ_HDR
, sizeof (bpobj_phys_t
), tx
);
861 VERIFY0(zap_add(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
862 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
, tx
));
863 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
, dp
->dp_meta_objset
, obj
));
865 VERIFY0(dmu_objset_find_dp(dp
, dp
->dp_root_dir_obj
,
866 upgrade_dir_clones_cb
, tx
, DS_FIND_CHILDREN
| DS_FIND_SERIALIZE
));
870 dsl_pool_create_origin(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
875 ASSERT(dmu_tx_is_syncing(tx
));
876 ASSERT(dp
->dp_origin_snap
== NULL
);
877 ASSERT(rrw_held(&dp
->dp_config_rwlock
, RW_WRITER
));
879 /* create the origin dir, ds, & snap-ds */
880 dsobj
= dsl_dataset_create_sync(dp
->dp_root_dir
, ORIGIN_DIR_NAME
,
881 NULL
, 0, kcred
, NULL
, tx
);
882 VERIFY0(dsl_dataset_hold_obj(dp
, dsobj
, FTAG
, &ds
));
883 dsl_dataset_snapshot_sync_impl(ds
, ORIGIN_DIR_NAME
, tx
);
884 VERIFY0(dsl_dataset_hold_obj(dp
, dsl_dataset_phys(ds
)->ds_prev_snap_obj
,
885 dp
, &dp
->dp_origin_snap
));
886 dsl_dataset_rele(ds
, FTAG
);
890 dsl_pool_iput_taskq(dsl_pool_t
*dp
)
892 return (dp
->dp_iput_taskq
);
896 * Walk through the pool-wide zap object of temporary snapshot user holds
900 dsl_pool_clean_tmp_userrefs(dsl_pool_t
*dp
)
904 objset_t
*mos
= dp
->dp_meta_objset
;
905 uint64_t zapobj
= dp
->dp_tmp_userrefs_obj
;
910 ASSERT(spa_version(dp
->dp_spa
) >= SPA_VERSION_USERREFS
);
912 holds
= fnvlist_alloc();
914 for (zap_cursor_init(&zc
, mos
, zapobj
);
915 zap_cursor_retrieve(&zc
, &za
) == 0;
916 zap_cursor_advance(&zc
)) {
920 htag
= strchr(za
.za_name
, '-');
923 if (nvlist_lookup_nvlist(holds
, za
.za_name
, &tags
) != 0) {
924 tags
= fnvlist_alloc();
925 fnvlist_add_boolean(tags
, htag
);
926 fnvlist_add_nvlist(holds
, za
.za_name
, tags
);
929 fnvlist_add_boolean(tags
, htag
);
932 dsl_dataset_user_release_tmp(dp
, holds
);
934 zap_cursor_fini(&zc
);
938 * Create the pool-wide zap object for storing temporary snapshot holds.
941 dsl_pool_user_hold_create_obj(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
943 objset_t
*mos
= dp
->dp_meta_objset
;
945 ASSERT(dp
->dp_tmp_userrefs_obj
== 0);
946 ASSERT(dmu_tx_is_syncing(tx
));
948 dp
->dp_tmp_userrefs_obj
= zap_create_link(mos
, DMU_OT_USERREFS
,
949 DMU_POOL_DIRECTORY_OBJECT
, DMU_POOL_TMP_USERREFS
, tx
);
953 dsl_pool_user_hold_rele_impl(dsl_pool_t
*dp
, uint64_t dsobj
,
954 const char *tag
, uint64_t now
, dmu_tx_t
*tx
, boolean_t holding
)
956 objset_t
*mos
= dp
->dp_meta_objset
;
957 uint64_t zapobj
= dp
->dp_tmp_userrefs_obj
;
961 ASSERT(spa_version(dp
->dp_spa
) >= SPA_VERSION_USERREFS
);
962 ASSERT(dmu_tx_is_syncing(tx
));
965 * If the pool was created prior to SPA_VERSION_USERREFS, the
966 * zap object for temporary holds might not exist yet.
970 dsl_pool_user_hold_create_obj(dp
, tx
);
971 zapobj
= dp
->dp_tmp_userrefs_obj
;
973 return (SET_ERROR(ENOENT
));
977 name
= kmem_asprintf("%llx-%s", (u_longlong_t
)dsobj
, tag
);
979 error
= zap_add(mos
, zapobj
, name
, 8, 1, &now
, tx
);
981 error
= zap_remove(mos
, zapobj
, name
, tx
);
988 * Add a temporary hold for the given dataset object and tag.
991 dsl_pool_user_hold(dsl_pool_t
*dp
, uint64_t dsobj
, const char *tag
,
992 uint64_t now
, dmu_tx_t
*tx
)
994 return (dsl_pool_user_hold_rele_impl(dp
, dsobj
, tag
, now
, tx
, B_TRUE
));
998 * Release a temporary hold for the given dataset object and tag.
1001 dsl_pool_user_release(dsl_pool_t
*dp
, uint64_t dsobj
, const char *tag
,
1004 return (dsl_pool_user_hold_rele_impl(dp
, dsobj
, tag
, 0,
1009 * DSL Pool Configuration Lock
1011 * The dp_config_rwlock protects against changes to DSL state (e.g. dataset
1012 * creation / destruction / rename / property setting). It must be held for
1013 * read to hold a dataset or dsl_dir. I.e. you must call
1014 * dsl_pool_config_enter() or dsl_pool_hold() before calling
1015 * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock
1016 * must be held continuously until all datasets and dsl_dirs are released.
1018 * The only exception to this rule is that if a "long hold" is placed on
1019 * a dataset, then the dp_config_rwlock may be dropped while the dataset
1020 * is still held. The long hold will prevent the dataset from being
1021 * destroyed -- the destroy will fail with EBUSY. A long hold can be
1022 * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset
1023 * (by calling dsl_{dataset,objset}_{try}own{_obj}).
1025 * Legitimate long-holders (including owners) should be long-running, cancelable
1026 * tasks that should cause "zfs destroy" to fail. This includes DMU
1027 * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open),
1028 * "zfs send", and "zfs diff". There are several other long-holders whose
1029 * uses are suboptimal (e.g. "zfs promote", and zil_suspend()).
1031 * The usual formula for long-holding would be:
1033 * dsl_dataset_hold()
1034 * ... perform checks ...
1035 * dsl_dataset_long_hold()
1037 * ... perform long-running task ...
1038 * dsl_dataset_long_rele()
1039 * dsl_dataset_rele()
1041 * Note that when the long hold is released, the dataset is still held but
1042 * the pool is not held. The dataset may change arbitrarily during this time
1043 * (e.g. it could be destroyed). Therefore you shouldn't do anything to the
1044 * dataset except release it.
1046 * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only
1047 * or modifying operations.
1049 * Modifying operations should generally use dsl_sync_task(). The synctask
1050 * infrastructure enforces proper locking strategy with respect to the
1051 * dp_config_rwlock. See the comment above dsl_sync_task() for details.
1053 * Read-only operations will manually hold the pool, then the dataset, obtain
1054 * information from the dataset, then release the pool and dataset.
1055 * dmu_objset_{hold,rele}() are convenience routines that also do the pool
1060 dsl_pool_hold(const char *name
, void *tag
, dsl_pool_t
**dp
)
1065 error
= spa_open(name
, &spa
, tag
);
1067 *dp
= spa_get_dsl(spa
);
1068 dsl_pool_config_enter(*dp
, tag
);
1074 dsl_pool_rele(dsl_pool_t
*dp
, void *tag
)
1076 dsl_pool_config_exit(dp
, tag
);
1077 spa_close(dp
->dp_spa
, tag
);
1081 dsl_pool_config_enter(dsl_pool_t
*dp
, void *tag
)
1084 * We use a "reentrant" reader-writer lock, but not reentrantly.
1086 * The rrwlock can (with the track_all flag) track all reading threads,
1087 * which is very useful for debugging which code path failed to release
1088 * the lock, and for verifying that the *current* thread does hold
1091 * (Unlike a rwlock, which knows that N threads hold it for
1092 * read, but not *which* threads, so rw_held(RW_READER) returns TRUE
1093 * if any thread holds it for read, even if this thread doesn't).
1095 ASSERT(!rrw_held(&dp
->dp_config_rwlock
, RW_READER
));
1096 rrw_enter(&dp
->dp_config_rwlock
, RW_READER
, tag
);
1100 dsl_pool_config_enter_prio(dsl_pool_t
*dp
, void *tag
)
1102 ASSERT(!rrw_held(&dp
->dp_config_rwlock
, RW_READER
));
1103 rrw_enter_read_prio(&dp
->dp_config_rwlock
, tag
);
1107 dsl_pool_config_exit(dsl_pool_t
*dp
, void *tag
)
1109 rrw_exit(&dp
->dp_config_rwlock
, tag
);
1113 dsl_pool_config_held(dsl_pool_t
*dp
)
1115 return (RRW_LOCK_HELD(&dp
->dp_config_rwlock
));
1119 dsl_pool_config_held_writer(dsl_pool_t
*dp
)
1121 return (RRW_WRITE_HELD(&dp
->dp_config_rwlock
));
1124 #if defined(_KERNEL) && defined(HAVE_SPL)
1125 EXPORT_SYMBOL(dsl_pool_config_enter
);
1126 EXPORT_SYMBOL(dsl_pool_config_exit
);
1129 /* zfs_dirty_data_max_percent only applied at module load in arc_init(). */
1130 module_param(zfs_dirty_data_max_percent
, int, 0444);
1131 MODULE_PARM_DESC(zfs_dirty_data_max_percent
, "percent of ram can be dirty");
1133 /* zfs_dirty_data_max_max_percent only applied at module load in arc_init(). */
1134 module_param(zfs_dirty_data_max_max_percent
, int, 0444);
1135 MODULE_PARM_DESC(zfs_dirty_data_max_max_percent
,
1136 "zfs_dirty_data_max upper bound as % of RAM");
1138 module_param(zfs_delay_min_dirty_percent
, int, 0644);
1139 MODULE_PARM_DESC(zfs_delay_min_dirty_percent
, "transaction delay threshold");
1141 module_param(zfs_dirty_data_max
, ulong
, 0644);
1142 MODULE_PARM_DESC(zfs_dirty_data_max
, "determines the dirty space limit");
1144 /* zfs_dirty_data_max_max only applied at module load in arc_init(). */
1145 module_param(zfs_dirty_data_max_max
, ulong
, 0444);
1146 MODULE_PARM_DESC(zfs_dirty_data_max_max
,
1147 "zfs_dirty_data_max upper bound in bytes");
1149 module_param(zfs_dirty_data_sync
, ulong
, 0644);
1150 MODULE_PARM_DESC(zfs_dirty_data_sync
, "sync txg when this much dirty data");
1152 module_param(zfs_delay_scale
, ulong
, 0644);
1153 MODULE_PARM_DESC(zfs_delay_scale
, "how quickly delay approaches infinity");
1155 module_param(zfs_sync_taskq_batch_pct
, int, 0644);
1156 MODULE_PARM_DESC(zfs_sync_taskq_batch_pct
,
1157 "max percent of CPUs that are used to sync dirty data");