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>
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).
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).
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.
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).
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.
91 * The delay is also calculated based on the amount of dirty data. See the
92 * comment above dmu_tx_delay() for details.
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 with a module
100 unsigned long zfs_dirty_data_max
= 0;
101 unsigned long zfs_dirty_data_max_max
= 0;
102 int zfs_dirty_data_max_percent
= 10;
103 int zfs_dirty_data_max_max_percent
= 25;
106 * If there is at least this much dirty data, push out a txg.
108 unsigned long zfs_dirty_data_sync
= 64 * 1024 * 1024;
111 * Once there is this amount of dirty data, the dmu_tx_delay() will kick in
112 * and delay each transaction.
113 * This value should be >= zfs_vdev_async_write_active_max_dirty_percent.
115 int zfs_delay_min_dirty_percent
= 60;
118 * This controls how quickly the delay approaches infinity.
119 * Larger values cause it to delay more for a given amount of dirty data.
120 * Therefore larger values will cause there to be less dirty data for a
123 * For the smoothest delay, this value should be about 1 billion divided
124 * by the maximum number of operations per second. This will smoothly
125 * handle between 10x and 1/10th this number.
127 * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the
128 * multiply in dmu_tx_delay().
130 unsigned long zfs_delay_scale
= 1000 * 1000 * 1000 / 2000;
133 * This determines the number of threads used by the dp_sync_taskq.
135 int zfs_sync_taskq_batch_pct
= 75;
138 dsl_pool_open_special_dir(dsl_pool_t
*dp
, const char *name
, dsl_dir_t
**ddp
)
143 err
= zap_lookup(dp
->dp_meta_objset
,
144 dsl_dir_phys(dp
->dp_root_dir
)->dd_child_dir_zapobj
,
145 name
, sizeof (obj
), 1, &obj
);
149 return (dsl_dir_hold_obj(dp
, obj
, name
, dp
, ddp
));
153 dsl_pool_open_impl(spa_t
*spa
, uint64_t txg
)
156 blkptr_t
*bp
= spa_get_rootblkptr(spa
);
158 dp
= kmem_zalloc(sizeof (dsl_pool_t
), KM_SLEEP
);
160 dp
->dp_meta_rootbp
= *bp
;
161 rrw_init(&dp
->dp_config_rwlock
, B_TRUE
);
164 txg_list_create(&dp
->dp_dirty_datasets
, spa
,
165 offsetof(dsl_dataset_t
, ds_dirty_link
));
166 txg_list_create(&dp
->dp_dirty_zilogs
, spa
,
167 offsetof(zilog_t
, zl_dirty_link
));
168 txg_list_create(&dp
->dp_dirty_dirs
, spa
,
169 offsetof(dsl_dir_t
, dd_dirty_link
));
170 txg_list_create(&dp
->dp_sync_tasks
, spa
,
171 offsetof(dsl_sync_task_t
, dst_node
));
173 dp
->dp_sync_taskq
= taskq_create("dp_sync_taskq",
174 zfs_sync_taskq_batch_pct
, minclsyspri
, 1, INT_MAX
,
175 TASKQ_THREADS_CPU_PCT
);
177 mutex_init(&dp
->dp_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
178 cv_init(&dp
->dp_spaceavail_cv
, NULL
, CV_DEFAULT
, NULL
);
180 dp
->dp_iput_taskq
= taskq_create("z_iput", max_ncpus
, defclsyspri
,
181 max_ncpus
* 8, INT_MAX
, TASKQ_PREPOPULATE
| TASKQ_DYNAMIC
);
187 dsl_pool_init(spa_t
*spa
, uint64_t txg
, dsl_pool_t
**dpp
)
190 dsl_pool_t
*dp
= dsl_pool_open_impl(spa
, txg
);
193 * Initialize the caller's dsl_pool_t structure before we actually open
194 * the meta objset. This is done because a self-healing write zio may
195 * be issued as part of dmu_objset_open_impl() and the spa needs its
196 * dsl_pool_t initialized in order to handle the write.
200 err
= dmu_objset_open_impl(spa
, NULL
, &dp
->dp_meta_rootbp
,
201 &dp
->dp_meta_objset
);
211 dsl_pool_open(dsl_pool_t
*dp
)
218 rrw_enter(&dp
->dp_config_rwlock
, RW_WRITER
, FTAG
);
219 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
220 DMU_POOL_ROOT_DATASET
, sizeof (uint64_t), 1,
221 &dp
->dp_root_dir_obj
);
225 err
= dsl_dir_hold_obj(dp
, dp
->dp_root_dir_obj
,
226 NULL
, dp
, &dp
->dp_root_dir
);
230 err
= dsl_pool_open_special_dir(dp
, MOS_DIR_NAME
, &dp
->dp_mos_dir
);
234 if (spa_version(dp
->dp_spa
) >= SPA_VERSION_ORIGIN
) {
235 err
= dsl_pool_open_special_dir(dp
, ORIGIN_DIR_NAME
, &dd
);
238 err
= dsl_dataset_hold_obj(dp
,
239 dsl_dir_phys(dd
)->dd_head_dataset_obj
, FTAG
, &ds
);
241 err
= dsl_dataset_hold_obj(dp
,
242 dsl_dataset_phys(ds
)->ds_prev_snap_obj
, dp
,
243 &dp
->dp_origin_snap
);
244 dsl_dataset_rele(ds
, FTAG
);
246 dsl_dir_rele(dd
, dp
);
251 if (spa_version(dp
->dp_spa
) >= SPA_VERSION_DEADLISTS
) {
252 err
= dsl_pool_open_special_dir(dp
, FREE_DIR_NAME
,
257 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
258 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
);
261 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
,
262 dp
->dp_meta_objset
, obj
));
266 * Note: errors ignored, because the leak dir will not exist if we
267 * have not encountered a leak yet.
269 (void) dsl_pool_open_special_dir(dp
, LEAK_DIR_NAME
,
272 if (spa_feature_is_active(dp
->dp_spa
, SPA_FEATURE_ASYNC_DESTROY
)) {
273 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
274 DMU_POOL_BPTREE_OBJ
, sizeof (uint64_t), 1,
280 if (spa_feature_is_active(dp
->dp_spa
, SPA_FEATURE_EMPTY_BPOBJ
)) {
281 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
282 DMU_POOL_EMPTY_BPOBJ
, sizeof (uint64_t), 1,
283 &dp
->dp_empty_bpobj
);
288 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
289 DMU_POOL_TMP_USERREFS
, sizeof (uint64_t), 1,
290 &dp
->dp_tmp_userrefs_obj
);
296 err
= dsl_scan_init(dp
, dp
->dp_tx
.tx_open_txg
);
299 rrw_exit(&dp
->dp_config_rwlock
, FTAG
);
304 dsl_pool_close(dsl_pool_t
*dp
)
307 * Drop our references from dsl_pool_open().
309 * Since we held the origin_snap from "syncing" context (which
310 * includes pool-opening context), it actually only got a "ref"
311 * and not a hold, so just drop that here.
313 if (dp
->dp_origin_snap
)
314 dsl_dataset_rele(dp
->dp_origin_snap
, dp
);
316 dsl_dir_rele(dp
->dp_mos_dir
, dp
);
318 dsl_dir_rele(dp
->dp_free_dir
, dp
);
320 dsl_dir_rele(dp
->dp_leak_dir
, dp
);
322 dsl_dir_rele(dp
->dp_root_dir
, dp
);
324 bpobj_close(&dp
->dp_free_bpobj
);
326 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
327 if (dp
->dp_meta_objset
)
328 dmu_objset_evict(dp
->dp_meta_objset
);
330 txg_list_destroy(&dp
->dp_dirty_datasets
);
331 txg_list_destroy(&dp
->dp_dirty_zilogs
);
332 txg_list_destroy(&dp
->dp_sync_tasks
);
333 txg_list_destroy(&dp
->dp_dirty_dirs
);
335 taskq_destroy(dp
->dp_sync_taskq
);
338 * We can't set retry to TRUE since we're explicitly specifying
339 * a spa to flush. This is good enough; any missed buffers for
340 * this spa won't cause trouble, and they'll eventually fall
341 * out of the ARC just like any other unused buffer.
343 arc_flush(dp
->dp_spa
, FALSE
);
347 dmu_buf_user_evict_wait();
349 rrw_destroy(&dp
->dp_config_rwlock
);
350 mutex_destroy(&dp
->dp_lock
);
351 cv_destroy(&dp
->dp_spaceavail_cv
);
352 taskq_destroy(dp
->dp_iput_taskq
);
354 vmem_free(dp
->dp_blkstats
, sizeof (zfs_all_blkstats_t
));
355 kmem_free(dp
, sizeof (dsl_pool_t
));
359 dsl_pool_create(spa_t
*spa
, nvlist_t
*zplprops
, uint64_t txg
)
362 dsl_pool_t
*dp
= dsl_pool_open_impl(spa
, txg
);
363 dmu_tx_t
*tx
= dmu_tx_create_assigned(dp
, txg
);
368 rrw_enter(&dp
->dp_config_rwlock
, RW_WRITER
, FTAG
);
370 /* create and open the MOS (meta-objset) */
371 dp
->dp_meta_objset
= dmu_objset_create_impl(spa
,
372 NULL
, &dp
->dp_meta_rootbp
, DMU_OST_META
, tx
);
374 /* create the pool directory */
375 err
= zap_create_claim(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
376 DMU_OT_OBJECT_DIRECTORY
, DMU_OT_NONE
, 0, tx
);
379 /* Initialize scan structures */
380 VERIFY0(dsl_scan_init(dp
, txg
));
382 /* create and open the root dir */
383 dp
->dp_root_dir_obj
= dsl_dir_create_sync(dp
, NULL
, NULL
, tx
);
384 VERIFY0(dsl_dir_hold_obj(dp
, dp
->dp_root_dir_obj
,
385 NULL
, dp
, &dp
->dp_root_dir
));
387 /* create and open the meta-objset dir */
388 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
, MOS_DIR_NAME
, tx
);
389 VERIFY0(dsl_pool_open_special_dir(dp
,
390 MOS_DIR_NAME
, &dp
->dp_mos_dir
));
392 if (spa_version(spa
) >= SPA_VERSION_DEADLISTS
) {
393 /* create and open the free dir */
394 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
,
396 VERIFY0(dsl_pool_open_special_dir(dp
,
397 FREE_DIR_NAME
, &dp
->dp_free_dir
));
399 /* create and open the free_bplist */
400 obj
= bpobj_alloc(dp
->dp_meta_objset
, SPA_OLD_MAXBLOCKSIZE
, tx
);
401 VERIFY(zap_add(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
402 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
, tx
) == 0);
403 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
,
404 dp
->dp_meta_objset
, obj
));
407 if (spa_version(spa
) >= SPA_VERSION_DSL_SCRUB
)
408 dsl_pool_create_origin(dp
, tx
);
410 /* create the root dataset */
411 obj
= dsl_dataset_create_sync_dd(dp
->dp_root_dir
, NULL
, 0, tx
);
413 /* create the root objset */
414 VERIFY0(dsl_dataset_hold_obj(dp
, obj
, FTAG
, &ds
));
415 rrw_enter(&ds
->ds_bp_rwlock
, RW_READER
, FTAG
);
416 VERIFY(NULL
!= (os
= dmu_objset_create_impl(dp
->dp_spa
, ds
,
417 dsl_dataset_get_blkptr(ds
), DMU_OST_ZFS
, tx
)));
418 rrw_exit(&ds
->ds_bp_rwlock
, FTAG
);
420 zfs_create_fs(os
, kcred
, zplprops
, tx
);
422 dsl_dataset_rele(ds
, FTAG
);
426 rrw_exit(&dp
->dp_config_rwlock
, FTAG
);
432 * Account for the meta-objset space in its placeholder dsl_dir.
435 dsl_pool_mos_diduse_space(dsl_pool_t
*dp
,
436 int64_t used
, int64_t comp
, int64_t uncomp
)
438 ASSERT3U(comp
, ==, uncomp
); /* it's all metadata */
439 mutex_enter(&dp
->dp_lock
);
440 dp
->dp_mos_used_delta
+= used
;
441 dp
->dp_mos_compressed_delta
+= comp
;
442 dp
->dp_mos_uncompressed_delta
+= uncomp
;
443 mutex_exit(&dp
->dp_lock
);
447 dsl_pool_sync_mos(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
449 zio_t
*zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
450 dmu_objset_sync(dp
->dp_meta_objset
, zio
, tx
);
451 VERIFY0(zio_wait(zio
));
452 dprintf_bp(&dp
->dp_meta_rootbp
, "meta objset rootbp is %s", "");
453 spa_set_rootblkptr(dp
->dp_spa
, &dp
->dp_meta_rootbp
);
457 dsl_pool_dirty_delta(dsl_pool_t
*dp
, int64_t delta
)
459 ASSERT(MUTEX_HELD(&dp
->dp_lock
));
462 ASSERT3U(-delta
, <=, dp
->dp_dirty_total
);
464 dp
->dp_dirty_total
+= delta
;
467 * Note: we signal even when increasing dp_dirty_total.
468 * This ensures forward progress -- each thread wakes the next waiter.
470 if (dp
->dp_dirty_total
< zfs_dirty_data_max
)
471 cv_signal(&dp
->dp_spaceavail_cv
);
475 dsl_pool_sync(dsl_pool_t
*dp
, uint64_t txg
)
481 objset_t
*mos
= dp
->dp_meta_objset
;
482 list_t synced_datasets
;
484 list_create(&synced_datasets
, sizeof (dsl_dataset_t
),
485 offsetof(dsl_dataset_t
, ds_synced_link
));
487 tx
= dmu_tx_create_assigned(dp
, txg
);
490 * Write out all dirty blocks of dirty datasets.
492 zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
493 while ((ds
= txg_list_remove(&dp
->dp_dirty_datasets
, txg
)) != NULL
) {
495 * We must not sync any non-MOS datasets twice, because
496 * we may have taken a snapshot of them. However, we
497 * may sync newly-created datasets on pass 2.
499 ASSERT(!list_link_active(&ds
->ds_synced_link
));
500 list_insert_tail(&synced_datasets
, ds
);
501 dsl_dataset_sync(ds
, zio
, tx
);
503 VERIFY0(zio_wait(zio
));
506 * We have written all of the accounted dirty data, so our
507 * dp_space_towrite should now be zero. However, some seldom-used
508 * code paths do not adhere to this (e.g. dbuf_undirty(), also
509 * rounding error in dbuf_write_physdone).
510 * Shore up the accounting of any dirtied space now.
512 dsl_pool_undirty_space(dp
, dp
->dp_dirty_pertxg
[txg
& TXG_MASK
], txg
);
515 * Update the long range free counter after
516 * we're done syncing user data
518 mutex_enter(&dp
->dp_lock
);
519 ASSERT(spa_sync_pass(dp
->dp_spa
) == 1 ||
520 dp
->dp_long_free_dirty_pertxg
[txg
& TXG_MASK
] == 0);
521 dp
->dp_long_free_dirty_pertxg
[txg
& TXG_MASK
] = 0;
522 mutex_exit(&dp
->dp_lock
);
525 * After the data blocks have been written (ensured by the zio_wait()
526 * above), update the user/group space accounting. This happens
527 * in tasks dispatched to dp_sync_taskq, so wait for them before
530 for (ds
= list_head(&synced_datasets
); ds
!= NULL
;
531 ds
= list_next(&synced_datasets
, ds
)) {
532 dmu_objset_do_userquota_updates(ds
->ds_objset
, tx
);
534 taskq_wait(dp
->dp_sync_taskq
);
537 * Sync the datasets again to push out the changes due to
538 * userspace updates. This must be done before we process the
539 * sync tasks, so that any snapshots will have the correct
540 * user accounting information (and we won't get confused
541 * about which blocks are part of the snapshot).
543 zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
544 while ((ds
= txg_list_remove(&dp
->dp_dirty_datasets
, txg
)) != NULL
) {
545 ASSERT(list_link_active(&ds
->ds_synced_link
));
546 dmu_buf_rele(ds
->ds_dbuf
, ds
);
547 dsl_dataset_sync(ds
, zio
, tx
);
549 VERIFY0(zio_wait(zio
));
552 * Now that the datasets have been completely synced, we can
553 * clean up our in-memory structures accumulated while syncing:
555 * - move dead blocks from the pending deadlist to the on-disk deadlist
556 * - release hold from dsl_dataset_dirty()
558 while ((ds
= list_remove_head(&synced_datasets
)) != NULL
) {
559 dsl_dataset_sync_done(ds
, tx
);
562 while ((dd
= txg_list_remove(&dp
->dp_dirty_dirs
, txg
)) != NULL
) {
563 dsl_dir_sync(dd
, tx
);
567 * The MOS's space is accounted for in the pool/$MOS
568 * (dp_mos_dir). We can't modify the mos while we're syncing
569 * it, so we remember the deltas and apply them here.
571 if (dp
->dp_mos_used_delta
!= 0 || dp
->dp_mos_compressed_delta
!= 0 ||
572 dp
->dp_mos_uncompressed_delta
!= 0) {
573 dsl_dir_diduse_space(dp
->dp_mos_dir
, DD_USED_HEAD
,
574 dp
->dp_mos_used_delta
,
575 dp
->dp_mos_compressed_delta
,
576 dp
->dp_mos_uncompressed_delta
, tx
);
577 dp
->dp_mos_used_delta
= 0;
578 dp
->dp_mos_compressed_delta
= 0;
579 dp
->dp_mos_uncompressed_delta
= 0;
582 if (!multilist_is_empty(mos
->os_dirty_dnodes
[txg
& TXG_MASK
])) {
583 dsl_pool_sync_mos(dp
, tx
);
587 * If we modify a dataset in the same txg that we want to destroy it,
588 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
589 * dsl_dir_destroy_check() will fail if there are unexpected holds.
590 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
591 * and clearing the hold on it) before we process the sync_tasks.
592 * The MOS data dirtied by the sync_tasks will be synced on the next
595 if (!txg_list_empty(&dp
->dp_sync_tasks
, txg
)) {
596 dsl_sync_task_t
*dst
;
598 * No more sync tasks should have been added while we
601 ASSERT3U(spa_sync_pass(dp
->dp_spa
), ==, 1);
602 while ((dst
= txg_list_remove(&dp
->dp_sync_tasks
, txg
)) != NULL
)
603 dsl_sync_task_sync(dst
, tx
);
608 DTRACE_PROBE2(dsl_pool_sync__done
, dsl_pool_t
*dp
, dp
, uint64_t, txg
);
612 dsl_pool_sync_done(dsl_pool_t
*dp
, uint64_t txg
)
616 while ((zilog
= txg_list_head(&dp
->dp_dirty_zilogs
, txg
))) {
617 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
619 * We don't remove the zilog from the dp_dirty_zilogs
620 * list until after we've cleaned it. This ensures that
621 * callers of zilog_is_dirty() receive an accurate
622 * answer when they are racing with the spa sync thread.
624 zil_clean(zilog
, txg
);
625 (void) txg_list_remove_this(&dp
->dp_dirty_zilogs
, zilog
, txg
);
626 ASSERT(!dmu_objset_is_dirty(zilog
->zl_os
, txg
));
627 dmu_buf_rele(ds
->ds_dbuf
, zilog
);
629 ASSERT(!dmu_objset_is_dirty(dp
->dp_meta_objset
, txg
));
633 * TRUE if the current thread is the tx_sync_thread or if we
634 * are being called from SPA context during pool initialization.
637 dsl_pool_sync_context(dsl_pool_t
*dp
)
639 return (curthread
== dp
->dp_tx
.tx_sync_thread
||
640 spa_is_initializing(dp
->dp_spa
) ||
641 taskq_member(dp
->dp_sync_taskq
, curthread
));
645 dsl_pool_adjustedsize(dsl_pool_t
*dp
, boolean_t netfree
)
647 uint64_t space
, resv
;
650 * If we're trying to assess whether it's OK to do a free,
651 * cut the reservation in half to allow forward progress
652 * (e.g. make it possible to rm(1) files from a full pool).
654 space
= spa_get_dspace(dp
->dp_spa
);
655 resv
= spa_get_slop_space(dp
->dp_spa
);
659 return (space
- resv
);
663 dsl_pool_need_dirty_delay(dsl_pool_t
*dp
)
665 uint64_t delay_min_bytes
=
666 zfs_dirty_data_max
* zfs_delay_min_dirty_percent
/ 100;
669 mutex_enter(&dp
->dp_lock
);
670 if (dp
->dp_dirty_total
> zfs_dirty_data_sync
)
672 rv
= (dp
->dp_dirty_total
> delay_min_bytes
);
673 mutex_exit(&dp
->dp_lock
);
678 dsl_pool_dirty_space(dsl_pool_t
*dp
, int64_t space
, dmu_tx_t
*tx
)
681 mutex_enter(&dp
->dp_lock
);
682 dp
->dp_dirty_pertxg
[tx
->tx_txg
& TXG_MASK
] += space
;
683 dsl_pool_dirty_delta(dp
, space
);
684 mutex_exit(&dp
->dp_lock
);
689 dsl_pool_undirty_space(dsl_pool_t
*dp
, int64_t space
, uint64_t txg
)
691 ASSERT3S(space
, >=, 0);
695 mutex_enter(&dp
->dp_lock
);
696 if (dp
->dp_dirty_pertxg
[txg
& TXG_MASK
] < space
) {
697 /* XXX writing something we didn't dirty? */
698 space
= dp
->dp_dirty_pertxg
[txg
& TXG_MASK
];
700 ASSERT3U(dp
->dp_dirty_pertxg
[txg
& TXG_MASK
], >=, space
);
701 dp
->dp_dirty_pertxg
[txg
& TXG_MASK
] -= space
;
702 ASSERT3U(dp
->dp_dirty_total
, >=, space
);
703 dsl_pool_dirty_delta(dp
, -space
);
704 mutex_exit(&dp
->dp_lock
);
709 upgrade_clones_cb(dsl_pool_t
*dp
, dsl_dataset_t
*hds
, void *arg
)
712 dsl_dataset_t
*ds
, *prev
= NULL
;
715 err
= dsl_dataset_hold_obj(dp
, hds
->ds_object
, FTAG
, &ds
);
719 while (dsl_dataset_phys(ds
)->ds_prev_snap_obj
!= 0) {
720 err
= dsl_dataset_hold_obj(dp
,
721 dsl_dataset_phys(ds
)->ds_prev_snap_obj
, FTAG
, &prev
);
723 dsl_dataset_rele(ds
, FTAG
);
727 if (dsl_dataset_phys(prev
)->ds_next_snap_obj
!= ds
->ds_object
)
729 dsl_dataset_rele(ds
, FTAG
);
735 prev
= dp
->dp_origin_snap
;
738 * The $ORIGIN can't have any data, or the accounting
741 rrw_enter(&ds
->ds_bp_rwlock
, RW_READER
, FTAG
);
742 ASSERT0(dsl_dataset_phys(prev
)->ds_bp
.blk_birth
);
743 rrw_exit(&ds
->ds_bp_rwlock
, FTAG
);
745 /* The origin doesn't get attached to itself */
746 if (ds
->ds_object
== prev
->ds_object
) {
747 dsl_dataset_rele(ds
, FTAG
);
751 dmu_buf_will_dirty(ds
->ds_dbuf
, tx
);
752 dsl_dataset_phys(ds
)->ds_prev_snap_obj
= prev
->ds_object
;
753 dsl_dataset_phys(ds
)->ds_prev_snap_txg
=
754 dsl_dataset_phys(prev
)->ds_creation_txg
;
756 dmu_buf_will_dirty(ds
->ds_dir
->dd_dbuf
, tx
);
757 dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
= prev
->ds_object
;
759 dmu_buf_will_dirty(prev
->ds_dbuf
, tx
);
760 dsl_dataset_phys(prev
)->ds_num_children
++;
762 if (dsl_dataset_phys(ds
)->ds_next_snap_obj
== 0) {
763 ASSERT(ds
->ds_prev
== NULL
);
764 VERIFY0(dsl_dataset_hold_obj(dp
,
765 dsl_dataset_phys(ds
)->ds_prev_snap_obj
,
770 ASSERT3U(dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
, ==, prev
->ds_object
);
771 ASSERT3U(dsl_dataset_phys(ds
)->ds_prev_snap_obj
, ==, prev
->ds_object
);
773 if (dsl_dataset_phys(prev
)->ds_next_clones_obj
== 0) {
774 dmu_buf_will_dirty(prev
->ds_dbuf
, tx
);
775 dsl_dataset_phys(prev
)->ds_next_clones_obj
=
776 zap_create(dp
->dp_meta_objset
,
777 DMU_OT_NEXT_CLONES
, DMU_OT_NONE
, 0, tx
);
779 VERIFY0(zap_add_int(dp
->dp_meta_objset
,
780 dsl_dataset_phys(prev
)->ds_next_clones_obj
, ds
->ds_object
, tx
));
782 dsl_dataset_rele(ds
, FTAG
);
783 if (prev
!= dp
->dp_origin_snap
)
784 dsl_dataset_rele(prev
, FTAG
);
789 dsl_pool_upgrade_clones(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
791 ASSERT(dmu_tx_is_syncing(tx
));
792 ASSERT(dp
->dp_origin_snap
!= NULL
);
794 VERIFY0(dmu_objset_find_dp(dp
, dp
->dp_root_dir_obj
, upgrade_clones_cb
,
795 tx
, DS_FIND_CHILDREN
| DS_FIND_SERIALIZE
));
800 upgrade_dir_clones_cb(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *arg
)
803 objset_t
*mos
= dp
->dp_meta_objset
;
805 if (dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
!= 0) {
806 dsl_dataset_t
*origin
;
808 VERIFY0(dsl_dataset_hold_obj(dp
,
809 dsl_dir_phys(ds
->ds_dir
)->dd_origin_obj
, FTAG
, &origin
));
811 if (dsl_dir_phys(origin
->ds_dir
)->dd_clones
== 0) {
812 dmu_buf_will_dirty(origin
->ds_dir
->dd_dbuf
, tx
);
813 dsl_dir_phys(origin
->ds_dir
)->dd_clones
=
814 zap_create(mos
, DMU_OT_DSL_CLONES
, DMU_OT_NONE
,
818 VERIFY0(zap_add_int(dp
->dp_meta_objset
,
819 dsl_dir_phys(origin
->ds_dir
)->dd_clones
,
822 dsl_dataset_rele(origin
, FTAG
);
828 dsl_pool_upgrade_dir_clones(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
832 ASSERT(dmu_tx_is_syncing(tx
));
834 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
, FREE_DIR_NAME
, tx
);
835 VERIFY0(dsl_pool_open_special_dir(dp
,
836 FREE_DIR_NAME
, &dp
->dp_free_dir
));
839 * We can't use bpobj_alloc(), because spa_version() still
840 * returns the old version, and we need a new-version bpobj with
841 * subobj support. So call dmu_object_alloc() directly.
843 obj
= dmu_object_alloc(dp
->dp_meta_objset
, DMU_OT_BPOBJ
,
844 SPA_OLD_MAXBLOCKSIZE
, DMU_OT_BPOBJ_HDR
, sizeof (bpobj_phys_t
), tx
);
845 VERIFY0(zap_add(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
846 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
, tx
));
847 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
, dp
->dp_meta_objset
, obj
));
849 VERIFY0(dmu_objset_find_dp(dp
, dp
->dp_root_dir_obj
,
850 upgrade_dir_clones_cb
, tx
, DS_FIND_CHILDREN
| DS_FIND_SERIALIZE
));
854 dsl_pool_create_origin(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
859 ASSERT(dmu_tx_is_syncing(tx
));
860 ASSERT(dp
->dp_origin_snap
== NULL
);
861 ASSERT(rrw_held(&dp
->dp_config_rwlock
, RW_WRITER
));
863 /* create the origin dir, ds, & snap-ds */
864 dsobj
= dsl_dataset_create_sync(dp
->dp_root_dir
, ORIGIN_DIR_NAME
,
866 VERIFY0(dsl_dataset_hold_obj(dp
, dsobj
, FTAG
, &ds
));
867 dsl_dataset_snapshot_sync_impl(ds
, ORIGIN_DIR_NAME
, tx
);
868 VERIFY0(dsl_dataset_hold_obj(dp
, dsl_dataset_phys(ds
)->ds_prev_snap_obj
,
869 dp
, &dp
->dp_origin_snap
));
870 dsl_dataset_rele(ds
, FTAG
);
874 dsl_pool_iput_taskq(dsl_pool_t
*dp
)
876 return (dp
->dp_iput_taskq
);
880 * Walk through the pool-wide zap object of temporary snapshot user holds
884 dsl_pool_clean_tmp_userrefs(dsl_pool_t
*dp
)
888 objset_t
*mos
= dp
->dp_meta_objset
;
889 uint64_t zapobj
= dp
->dp_tmp_userrefs_obj
;
894 ASSERT(spa_version(dp
->dp_spa
) >= SPA_VERSION_USERREFS
);
896 holds
= fnvlist_alloc();
898 for (zap_cursor_init(&zc
, mos
, zapobj
);
899 zap_cursor_retrieve(&zc
, &za
) == 0;
900 zap_cursor_advance(&zc
)) {
904 htag
= strchr(za
.za_name
, '-');
907 if (nvlist_lookup_nvlist(holds
, za
.za_name
, &tags
) != 0) {
908 tags
= fnvlist_alloc();
909 fnvlist_add_boolean(tags
, htag
);
910 fnvlist_add_nvlist(holds
, za
.za_name
, tags
);
913 fnvlist_add_boolean(tags
, htag
);
916 dsl_dataset_user_release_tmp(dp
, holds
);
918 zap_cursor_fini(&zc
);
922 * Create the pool-wide zap object for storing temporary snapshot holds.
925 dsl_pool_user_hold_create_obj(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
927 objset_t
*mos
= dp
->dp_meta_objset
;
929 ASSERT(dp
->dp_tmp_userrefs_obj
== 0);
930 ASSERT(dmu_tx_is_syncing(tx
));
932 dp
->dp_tmp_userrefs_obj
= zap_create_link(mos
, DMU_OT_USERREFS
,
933 DMU_POOL_DIRECTORY_OBJECT
, DMU_POOL_TMP_USERREFS
, tx
);
937 dsl_pool_user_hold_rele_impl(dsl_pool_t
*dp
, uint64_t dsobj
,
938 const char *tag
, uint64_t now
, dmu_tx_t
*tx
, boolean_t holding
)
940 objset_t
*mos
= dp
->dp_meta_objset
;
941 uint64_t zapobj
= dp
->dp_tmp_userrefs_obj
;
945 ASSERT(spa_version(dp
->dp_spa
) >= SPA_VERSION_USERREFS
);
946 ASSERT(dmu_tx_is_syncing(tx
));
949 * If the pool was created prior to SPA_VERSION_USERREFS, the
950 * zap object for temporary holds might not exist yet.
954 dsl_pool_user_hold_create_obj(dp
, tx
);
955 zapobj
= dp
->dp_tmp_userrefs_obj
;
957 return (SET_ERROR(ENOENT
));
961 name
= kmem_asprintf("%llx-%s", (u_longlong_t
)dsobj
, tag
);
963 error
= zap_add(mos
, zapobj
, name
, 8, 1, &now
, tx
);
965 error
= zap_remove(mos
, zapobj
, name
, tx
);
972 * Add a temporary hold for the given dataset object and tag.
975 dsl_pool_user_hold(dsl_pool_t
*dp
, uint64_t dsobj
, const char *tag
,
976 uint64_t now
, dmu_tx_t
*tx
)
978 return (dsl_pool_user_hold_rele_impl(dp
, dsobj
, tag
, now
, tx
, B_TRUE
));
982 * Release a temporary hold for the given dataset object and tag.
985 dsl_pool_user_release(dsl_pool_t
*dp
, uint64_t dsobj
, const char *tag
,
988 return (dsl_pool_user_hold_rele_impl(dp
, dsobj
, tag
, 0,
993 * DSL Pool Configuration Lock
995 * The dp_config_rwlock protects against changes to DSL state (e.g. dataset
996 * creation / destruction / rename / property setting). It must be held for
997 * read to hold a dataset or dsl_dir. I.e. you must call
998 * dsl_pool_config_enter() or dsl_pool_hold() before calling
999 * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock
1000 * must be held continuously until all datasets and dsl_dirs are released.
1002 * The only exception to this rule is that if a "long hold" is placed on
1003 * a dataset, then the dp_config_rwlock may be dropped while the dataset
1004 * is still held. The long hold will prevent the dataset from being
1005 * destroyed -- the destroy will fail with EBUSY. A long hold can be
1006 * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset
1007 * (by calling dsl_{dataset,objset}_{try}own{_obj}).
1009 * Legitimate long-holders (including owners) should be long-running, cancelable
1010 * tasks that should cause "zfs destroy" to fail. This includes DMU
1011 * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open),
1012 * "zfs send", and "zfs diff". There are several other long-holders whose
1013 * uses are suboptimal (e.g. "zfs promote", and zil_suspend()).
1015 * The usual formula for long-holding would be:
1017 * dsl_dataset_hold()
1018 * ... perform checks ...
1019 * dsl_dataset_long_hold()
1021 * ... perform long-running task ...
1022 * dsl_dataset_long_rele()
1023 * dsl_dataset_rele()
1025 * Note that when the long hold is released, the dataset is still held but
1026 * the pool is not held. The dataset may change arbitrarily during this time
1027 * (e.g. it could be destroyed). Therefore you shouldn't do anything to the
1028 * dataset except release it.
1030 * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only
1031 * or modifying operations.
1033 * Modifying operations should generally use dsl_sync_task(). The synctask
1034 * infrastructure enforces proper locking strategy with respect to the
1035 * dp_config_rwlock. See the comment above dsl_sync_task() for details.
1037 * Read-only operations will manually hold the pool, then the dataset, obtain
1038 * information from the dataset, then release the pool and dataset.
1039 * dmu_objset_{hold,rele}() are convenience routines that also do the pool
1044 dsl_pool_hold(const char *name
, void *tag
, dsl_pool_t
**dp
)
1049 error
= spa_open(name
, &spa
, tag
);
1051 *dp
= spa_get_dsl(spa
);
1052 dsl_pool_config_enter(*dp
, tag
);
1058 dsl_pool_rele(dsl_pool_t
*dp
, void *tag
)
1060 dsl_pool_config_exit(dp
, tag
);
1061 spa_close(dp
->dp_spa
, tag
);
1065 dsl_pool_config_enter(dsl_pool_t
*dp
, void *tag
)
1068 * We use a "reentrant" reader-writer lock, but not reentrantly.
1070 * The rrwlock can (with the track_all flag) track all reading threads,
1071 * which is very useful for debugging which code path failed to release
1072 * the lock, and for verifying that the *current* thread does hold
1075 * (Unlike a rwlock, which knows that N threads hold it for
1076 * read, but not *which* threads, so rw_held(RW_READER) returns TRUE
1077 * if any thread holds it for read, even if this thread doesn't).
1079 ASSERT(!rrw_held(&dp
->dp_config_rwlock
, RW_READER
));
1080 rrw_enter(&dp
->dp_config_rwlock
, RW_READER
, tag
);
1084 dsl_pool_config_enter_prio(dsl_pool_t
*dp
, void *tag
)
1086 ASSERT(!rrw_held(&dp
->dp_config_rwlock
, RW_READER
));
1087 rrw_enter_read_prio(&dp
->dp_config_rwlock
, tag
);
1091 dsl_pool_config_exit(dsl_pool_t
*dp
, void *tag
)
1093 rrw_exit(&dp
->dp_config_rwlock
, tag
);
1097 dsl_pool_config_held(dsl_pool_t
*dp
)
1099 return (RRW_LOCK_HELD(&dp
->dp_config_rwlock
));
1103 dsl_pool_config_held_writer(dsl_pool_t
*dp
)
1105 return (RRW_WRITE_HELD(&dp
->dp_config_rwlock
));
1108 #if defined(_KERNEL) && defined(HAVE_SPL)
1109 EXPORT_SYMBOL(dsl_pool_config_enter
);
1110 EXPORT_SYMBOL(dsl_pool_config_exit
);
1113 /* zfs_dirty_data_max_percent only applied at module load in arc_init(). */
1114 module_param(zfs_dirty_data_max_percent
, int, 0444);
1115 MODULE_PARM_DESC(zfs_dirty_data_max_percent
, "percent of ram can be dirty");
1117 /* zfs_dirty_data_max_max_percent only applied at module load in arc_init(). */
1118 module_param(zfs_dirty_data_max_max_percent
, int, 0444);
1119 MODULE_PARM_DESC(zfs_dirty_data_max_max_percent
,
1120 "zfs_dirty_data_max upper bound as % of RAM");
1122 module_param(zfs_delay_min_dirty_percent
, int, 0644);
1123 MODULE_PARM_DESC(zfs_delay_min_dirty_percent
, "transaction delay threshold");
1125 module_param(zfs_dirty_data_max
, ulong
, 0644);
1126 MODULE_PARM_DESC(zfs_dirty_data_max
, "determines the dirty space limit");
1128 /* zfs_dirty_data_max_max only applied at module load in arc_init(). */
1129 module_param(zfs_dirty_data_max_max
, ulong
, 0444);
1130 MODULE_PARM_DESC(zfs_dirty_data_max_max
,
1131 "zfs_dirty_data_max upper bound in bytes");
1133 module_param(zfs_dirty_data_sync
, ulong
, 0644);
1134 MODULE_PARM_DESC(zfs_dirty_data_sync
, "sync txg when this much dirty data");
1136 module_param(zfs_delay_scale
, ulong
, 0644);
1137 MODULE_PARM_DESC(zfs_delay_scale
, "how quickly delay approaches infinity");
1139 module_param(zfs_sync_taskq_batch_pct
, int, 0644);
1140 MODULE_PARM_DESC(zfs_sync_taskq_batch_pct
,
1141 "max percent of CPUs that are used to sync dirty data");