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) 2013 by Delphix. All rights reserved.
24 * Copyright (c) 2013 Steven Hartland. All rights reserved.
27 #include <sys/dsl_pool.h>
28 #include <sys/dsl_dataset.h>
29 #include <sys/dsl_prop.h>
30 #include <sys/dsl_dir.h>
31 #include <sys/dsl_synctask.h>
32 #include <sys/dsl_scan.h>
33 #include <sys/dnode.h>
34 #include <sys/dmu_tx.h>
35 #include <sys/dmu_objset.h>
39 #include <sys/zfs_context.h>
40 #include <sys/fs/zfs.h>
41 #include <sys/zfs_znode.h>
42 #include <sys/spa_impl.h>
43 #include <sys/dsl_deadlist.h>
44 #include <sys/bptree.h>
45 #include <sys/zfeature.h>
46 #include <sys/zil_impl.h>
47 #include <sys/dsl_userhold.h>
53 * ZFS must limit the rate of incoming writes to the rate at which it is able
54 * to sync data modifications to the backend storage. Throttling by too much
55 * creates an artificial limit; throttling by too little can only be sustained
56 * for short periods and would lead to highly lumpy performance. On a per-pool
57 * basis, ZFS tracks the amount of modified (dirty) data. As operations change
58 * data, the amount of dirty data increases; as ZFS syncs out data, the amount
59 * of dirty data decreases. When the amount of dirty data exceeds a
60 * predetermined threshold further modifications are blocked until the amount
61 * of dirty data decreases (as data is synced out).
63 * The limit on dirty data is tunable, and should be adjusted according to
64 * both the IO capacity and available memory of the system. The larger the
65 * window, the more ZFS is able to aggregate and amortize metadata (and data)
66 * changes. However, memory is a limited resource, and allowing for more dirty
67 * data comes at the cost of keeping other useful data in memory (for example
68 * ZFS data cached by the ARC).
72 * As buffers are modified dsl_pool_willuse_space() increments both the per-
73 * txg (dp_dirty_pertxg[]) and poolwide (dp_dirty_total) accounting of
74 * dirty space used; dsl_pool_dirty_space() decrements those values as data
75 * is synced out from dsl_pool_sync(). While only the poolwide value is
76 * relevant, the per-txg value is useful for debugging. The tunable
77 * zfs_dirty_data_max determines the dirty space limit. Once that value is
78 * exceeded, new writes are halted until space frees up.
80 * The zfs_dirty_data_sync tunable dictates the threshold at which we
81 * ensure that there is a txg syncing (see the comment in txg.c for a full
82 * description of transaction group stages).
84 * The IO scheduler uses both the dirty space limit and current amount of
85 * dirty data as inputs. Those values affect the number of concurrent IOs ZFS
86 * issues. See the comment in vdev_queue.c for details of the IO scheduler.
88 * The delay is also calculated based on the amount of dirty data. See the
89 * comment above dmu_tx_delay() for details.
93 * zfs_dirty_data_max will be set to zfs_dirty_data_max_percent% of all memory,
94 * capped at zfs_dirty_data_max_max. It can also be overridden with a module
97 unsigned long zfs_dirty_data_max
= 0;
98 unsigned long zfs_dirty_data_max_max
= 0;
99 int zfs_dirty_data_max_percent
= 10;
100 int zfs_dirty_data_max_max_percent
= 25;
103 * If there is at least this much dirty data, push out a txg.
105 unsigned long zfs_dirty_data_sync
= 64 * 1024 * 1024;
108 * Once there is this amount of dirty data, the dmu_tx_delay() will kick in
109 * and delay each transaction.
110 * This value should be >= zfs_vdev_async_write_active_max_dirty_percent.
112 int zfs_delay_min_dirty_percent
= 60;
115 * This controls how quickly the delay approaches infinity.
116 * Larger values cause it to delay more for a given amount of dirty data.
117 * Therefore larger values will cause there to be less dirty data for a
120 * For the smoothest delay, this value should be about 1 billion divided
121 * by the maximum number of operations per second. This will smoothly
122 * handle between 10x and 1/10th this number.
124 * Note: zfs_delay_scale * zfs_dirty_data_max must be < 2^64, due to the
125 * multiply in dmu_tx_delay().
127 unsigned long zfs_delay_scale
= 1000 * 1000 * 1000 / 2000;
129 hrtime_t zfs_throttle_delay
= MSEC2NSEC(10);
130 hrtime_t zfs_throttle_resolution
= MSEC2NSEC(10);
133 dsl_pool_open_special_dir(dsl_pool_t
*dp
, const char *name
, dsl_dir_t
**ddp
)
138 err
= zap_lookup(dp
->dp_meta_objset
,
139 dp
->dp_root_dir
->dd_phys
->dd_child_dir_zapobj
,
140 name
, sizeof (obj
), 1, &obj
);
144 return (dsl_dir_hold_obj(dp
, obj
, name
, dp
, ddp
));
148 dsl_pool_open_impl(spa_t
*spa
, uint64_t txg
)
151 blkptr_t
*bp
= spa_get_rootblkptr(spa
);
153 dp
= kmem_zalloc(sizeof (dsl_pool_t
), KM_SLEEP
);
155 dp
->dp_meta_rootbp
= *bp
;
156 rrw_init(&dp
->dp_config_rwlock
, B_TRUE
);
159 txg_list_create(&dp
->dp_dirty_datasets
,
160 offsetof(dsl_dataset_t
, ds_dirty_link
));
161 txg_list_create(&dp
->dp_dirty_zilogs
,
162 offsetof(zilog_t
, zl_dirty_link
));
163 txg_list_create(&dp
->dp_dirty_dirs
,
164 offsetof(dsl_dir_t
, dd_dirty_link
));
165 txg_list_create(&dp
->dp_sync_tasks
,
166 offsetof(dsl_sync_task_t
, dst_node
));
168 mutex_init(&dp
->dp_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
169 cv_init(&dp
->dp_spaceavail_cv
, NULL
, CV_DEFAULT
, NULL
);
171 dp
->dp_iput_taskq
= taskq_create("zfs_iput_taskq", 1, minclsyspri
,
178 dsl_pool_init(spa_t
*spa
, uint64_t txg
, dsl_pool_t
**dpp
)
181 dsl_pool_t
*dp
= dsl_pool_open_impl(spa
, txg
);
183 err
= dmu_objset_open_impl(spa
, NULL
, &dp
->dp_meta_rootbp
,
184 &dp
->dp_meta_objset
);
194 dsl_pool_open(dsl_pool_t
*dp
)
201 rrw_enter(&dp
->dp_config_rwlock
, RW_WRITER
, FTAG
);
202 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
203 DMU_POOL_ROOT_DATASET
, sizeof (uint64_t), 1,
204 &dp
->dp_root_dir_obj
);
208 err
= dsl_dir_hold_obj(dp
, dp
->dp_root_dir_obj
,
209 NULL
, dp
, &dp
->dp_root_dir
);
213 err
= dsl_pool_open_special_dir(dp
, MOS_DIR_NAME
, &dp
->dp_mos_dir
);
217 if (spa_version(dp
->dp_spa
) >= SPA_VERSION_ORIGIN
) {
218 err
= dsl_pool_open_special_dir(dp
, ORIGIN_DIR_NAME
, &dd
);
221 err
= dsl_dataset_hold_obj(dp
, dd
->dd_phys
->dd_head_dataset_obj
,
224 err
= dsl_dataset_hold_obj(dp
,
225 ds
->ds_phys
->ds_prev_snap_obj
, dp
,
226 &dp
->dp_origin_snap
);
227 dsl_dataset_rele(ds
, FTAG
);
229 dsl_dir_rele(dd
, dp
);
234 if (spa_version(dp
->dp_spa
) >= SPA_VERSION_DEADLISTS
) {
235 err
= dsl_pool_open_special_dir(dp
, FREE_DIR_NAME
,
240 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
241 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
);
244 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
,
245 dp
->dp_meta_objset
, obj
));
248 if (spa_feature_is_active(dp
->dp_spa
,
249 &spa_feature_table
[SPA_FEATURE_ASYNC_DESTROY
])) {
250 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
251 DMU_POOL_BPTREE_OBJ
, sizeof (uint64_t), 1,
257 if (spa_feature_is_active(dp
->dp_spa
,
258 &spa_feature_table
[SPA_FEATURE_EMPTY_BPOBJ
])) {
259 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
260 DMU_POOL_EMPTY_BPOBJ
, sizeof (uint64_t), 1,
261 &dp
->dp_empty_bpobj
);
266 err
= zap_lookup(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
267 DMU_POOL_TMP_USERREFS
, sizeof (uint64_t), 1,
268 &dp
->dp_tmp_userrefs_obj
);
274 err
= dsl_scan_init(dp
, dp
->dp_tx
.tx_open_txg
);
277 rrw_exit(&dp
->dp_config_rwlock
, FTAG
);
282 dsl_pool_close(dsl_pool_t
*dp
)
285 * Drop our references from dsl_pool_open().
287 * Since we held the origin_snap from "syncing" context (which
288 * includes pool-opening context), it actually only got a "ref"
289 * and not a hold, so just drop that here.
291 if (dp
->dp_origin_snap
)
292 dsl_dataset_rele(dp
->dp_origin_snap
, dp
);
294 dsl_dir_rele(dp
->dp_mos_dir
, dp
);
296 dsl_dir_rele(dp
->dp_free_dir
, dp
);
298 dsl_dir_rele(dp
->dp_root_dir
, dp
);
300 bpobj_close(&dp
->dp_free_bpobj
);
302 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
303 if (dp
->dp_meta_objset
)
304 dmu_objset_evict(dp
->dp_meta_objset
);
306 txg_list_destroy(&dp
->dp_dirty_datasets
);
307 txg_list_destroy(&dp
->dp_dirty_zilogs
);
308 txg_list_destroy(&dp
->dp_sync_tasks
);
309 txg_list_destroy(&dp
->dp_dirty_dirs
);
311 arc_flush(dp
->dp_spa
);
314 rrw_destroy(&dp
->dp_config_rwlock
);
315 mutex_destroy(&dp
->dp_lock
);
316 taskq_destroy(dp
->dp_iput_taskq
);
318 kmem_free(dp
->dp_blkstats
, sizeof (zfs_all_blkstats_t
));
319 kmem_free(dp
, sizeof (dsl_pool_t
));
323 dsl_pool_create(spa_t
*spa
, nvlist_t
*zplprops
, uint64_t txg
)
326 dsl_pool_t
*dp
= dsl_pool_open_impl(spa
, txg
);
327 dmu_tx_t
*tx
= dmu_tx_create_assigned(dp
, txg
);
332 rrw_enter(&dp
->dp_config_rwlock
, RW_WRITER
, FTAG
);
334 /* create and open the MOS (meta-objset) */
335 dp
->dp_meta_objset
= dmu_objset_create_impl(spa
,
336 NULL
, &dp
->dp_meta_rootbp
, DMU_OST_META
, tx
);
338 /* create the pool directory */
339 err
= zap_create_claim(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
340 DMU_OT_OBJECT_DIRECTORY
, DMU_OT_NONE
, 0, tx
);
343 /* Initialize scan structures */
344 VERIFY0(dsl_scan_init(dp
, txg
));
346 /* create and open the root dir */
347 dp
->dp_root_dir_obj
= dsl_dir_create_sync(dp
, NULL
, NULL
, tx
);
348 VERIFY0(dsl_dir_hold_obj(dp
, dp
->dp_root_dir_obj
,
349 NULL
, dp
, &dp
->dp_root_dir
));
351 /* create and open the meta-objset dir */
352 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
, MOS_DIR_NAME
, tx
);
353 VERIFY0(dsl_pool_open_special_dir(dp
,
354 MOS_DIR_NAME
, &dp
->dp_mos_dir
));
356 if (spa_version(spa
) >= SPA_VERSION_DEADLISTS
) {
357 /* create and open the free dir */
358 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
,
360 VERIFY0(dsl_pool_open_special_dir(dp
,
361 FREE_DIR_NAME
, &dp
->dp_free_dir
));
363 /* create and open the free_bplist */
364 obj
= bpobj_alloc(dp
->dp_meta_objset
, SPA_MAXBLOCKSIZE
, tx
);
365 VERIFY(zap_add(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
366 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
, tx
) == 0);
367 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
,
368 dp
->dp_meta_objset
, obj
));
371 if (spa_version(spa
) >= SPA_VERSION_DSL_SCRUB
)
372 dsl_pool_create_origin(dp
, tx
);
374 /* create the root dataset */
375 obj
= dsl_dataset_create_sync_dd(dp
->dp_root_dir
, NULL
, 0, tx
);
377 /* create the root objset */
378 VERIFY0(dsl_dataset_hold_obj(dp
, obj
, FTAG
, &ds
));
379 VERIFY(NULL
!= (os
= dmu_objset_create_impl(dp
->dp_spa
, ds
,
380 dsl_dataset_get_blkptr(ds
), DMU_OST_ZFS
, tx
)));
382 zfs_create_fs(os
, kcred
, zplprops
, tx
);
384 dsl_dataset_rele(ds
, FTAG
);
388 rrw_exit(&dp
->dp_config_rwlock
, FTAG
);
394 * Account for the meta-objset space in its placeholder dsl_dir.
397 dsl_pool_mos_diduse_space(dsl_pool_t
*dp
,
398 int64_t used
, int64_t comp
, int64_t uncomp
)
400 ASSERT3U(comp
, ==, uncomp
); /* it's all metadata */
401 mutex_enter(&dp
->dp_lock
);
402 dp
->dp_mos_used_delta
+= used
;
403 dp
->dp_mos_compressed_delta
+= comp
;
404 dp
->dp_mos_uncompressed_delta
+= uncomp
;
405 mutex_exit(&dp
->dp_lock
);
409 deadlist_enqueue_cb(void *arg
, const blkptr_t
*bp
, dmu_tx_t
*tx
)
411 dsl_deadlist_t
*dl
= arg
;
412 dsl_deadlist_insert(dl
, bp
, tx
);
417 dsl_pool_sync_mos(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
419 zio_t
*zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
420 dmu_objset_sync(dp
->dp_meta_objset
, zio
, tx
);
421 VERIFY0(zio_wait(zio
));
422 dprintf_bp(&dp
->dp_meta_rootbp
, "meta objset rootbp is %s", "");
423 spa_set_rootblkptr(dp
->dp_spa
, &dp
->dp_meta_rootbp
);
427 dsl_pool_dirty_delta(dsl_pool_t
*dp
, int64_t delta
)
429 ASSERT(MUTEX_HELD(&dp
->dp_lock
));
432 ASSERT3U(-delta
, <=, dp
->dp_dirty_total
);
434 dp
->dp_dirty_total
+= delta
;
437 * Note: we signal even when increasing dp_dirty_total.
438 * This ensures forward progress -- each thread wakes the next waiter.
440 if (dp
->dp_dirty_total
<= zfs_dirty_data_max
)
441 cv_signal(&dp
->dp_spaceavail_cv
);
445 dsl_pool_sync(dsl_pool_t
*dp
, uint64_t txg
)
451 objset_t
*mos
= dp
->dp_meta_objset
;
452 list_t synced_datasets
;
454 list_create(&synced_datasets
, sizeof (dsl_dataset_t
),
455 offsetof(dsl_dataset_t
, ds_synced_link
));
457 tx
= dmu_tx_create_assigned(dp
, txg
);
460 * Write out all dirty blocks of dirty datasets.
462 zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
463 while ((ds
= txg_list_remove(&dp
->dp_dirty_datasets
, txg
)) != NULL
) {
465 * We must not sync any non-MOS datasets twice, because
466 * we may have taken a snapshot of them. However, we
467 * may sync newly-created datasets on pass 2.
469 ASSERT(!list_link_active(&ds
->ds_synced_link
));
470 list_insert_tail(&synced_datasets
, ds
);
471 dsl_dataset_sync(ds
, zio
, tx
);
473 VERIFY0(zio_wait(zio
));
476 * We have written all of the accounted dirty data, so our
477 * dp_space_towrite should now be zero. However, some seldom-used
478 * code paths do not adhere to this (e.g. dbuf_undirty(), also
479 * rounding error in dbuf_write_physdone).
480 * Shore up the accounting of any dirtied space now.
482 dsl_pool_undirty_space(dp
, dp
->dp_dirty_pertxg
[txg
& TXG_MASK
], txg
);
485 * After the data blocks have been written (ensured by the zio_wait()
486 * above), update the user/group space accounting.
488 for (ds
= list_head(&synced_datasets
); ds
!= NULL
;
489 ds
= list_next(&synced_datasets
, ds
)) {
490 dmu_objset_do_userquota_updates(ds
->ds_objset
, tx
);
494 * Sync the datasets again to push out the changes due to
495 * userspace updates. This must be done before we process the
496 * sync tasks, so that any snapshots will have the correct
497 * user accounting information (and we won't get confused
498 * about which blocks are part of the snapshot).
500 zio
= zio_root(dp
->dp_spa
, NULL
, NULL
, ZIO_FLAG_MUSTSUCCEED
);
501 while ((ds
= txg_list_remove(&dp
->dp_dirty_datasets
, txg
)) != NULL
) {
502 ASSERT(list_link_active(&ds
->ds_synced_link
));
503 dmu_buf_rele(ds
->ds_dbuf
, ds
);
504 dsl_dataset_sync(ds
, zio
, tx
);
506 VERIFY0(zio_wait(zio
));
509 * Now that the datasets have been completely synced, we can
510 * clean up our in-memory structures accumulated while syncing:
512 * - move dead blocks from the pending deadlist to the on-disk deadlist
513 * - release hold from dsl_dataset_dirty()
515 while ((ds
= list_remove_head(&synced_datasets
)) != NULL
) {
516 ASSERTV(objset_t
*os
= ds
->ds_objset
);
517 bplist_iterate(&ds
->ds_pending_deadlist
,
518 deadlist_enqueue_cb
, &ds
->ds_deadlist
, tx
);
519 ASSERT(!dmu_objset_is_dirty(os
, txg
));
520 dmu_buf_rele(ds
->ds_dbuf
, ds
);
523 while ((dd
= txg_list_remove(&dp
->dp_dirty_dirs
, txg
)) != NULL
) {
524 dsl_dir_sync(dd
, tx
);
528 * The MOS's space is accounted for in the pool/$MOS
529 * (dp_mos_dir). We can't modify the mos while we're syncing
530 * it, so we remember the deltas and apply them here.
532 if (dp
->dp_mos_used_delta
!= 0 || dp
->dp_mos_compressed_delta
!= 0 ||
533 dp
->dp_mos_uncompressed_delta
!= 0) {
534 dsl_dir_diduse_space(dp
->dp_mos_dir
, DD_USED_HEAD
,
535 dp
->dp_mos_used_delta
,
536 dp
->dp_mos_compressed_delta
,
537 dp
->dp_mos_uncompressed_delta
, tx
);
538 dp
->dp_mos_used_delta
= 0;
539 dp
->dp_mos_compressed_delta
= 0;
540 dp
->dp_mos_uncompressed_delta
= 0;
543 if (list_head(&mos
->os_dirty_dnodes
[txg
& TXG_MASK
]) != NULL
||
544 list_head(&mos
->os_free_dnodes
[txg
& TXG_MASK
]) != NULL
) {
545 dsl_pool_sync_mos(dp
, tx
);
549 * If we modify a dataset in the same txg that we want to destroy it,
550 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
551 * dsl_dir_destroy_check() will fail if there are unexpected holds.
552 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
553 * and clearing the hold on it) before we process the sync_tasks.
554 * The MOS data dirtied by the sync_tasks will be synced on the next
557 if (!txg_list_empty(&dp
->dp_sync_tasks
, txg
)) {
558 dsl_sync_task_t
*dst
;
560 * No more sync tasks should have been added while we
563 ASSERT3U(spa_sync_pass(dp
->dp_spa
), ==, 1);
564 while ((dst
= txg_list_remove(&dp
->dp_sync_tasks
, txg
)) != NULL
)
565 dsl_sync_task_sync(dst
, tx
);
570 DTRACE_PROBE2(dsl_pool_sync__done
, dsl_pool_t
*dp
, dp
, uint64_t, txg
);
574 dsl_pool_sync_done(dsl_pool_t
*dp
, uint64_t txg
)
578 while ((zilog
= txg_list_remove(&dp
->dp_dirty_zilogs
, txg
))) {
579 dsl_dataset_t
*ds
= dmu_objset_ds(zilog
->zl_os
);
580 zil_clean(zilog
, txg
);
581 ASSERT(!dmu_objset_is_dirty(zilog
->zl_os
, txg
));
582 dmu_buf_rele(ds
->ds_dbuf
, zilog
);
584 ASSERT(!dmu_objset_is_dirty(dp
->dp_meta_objset
, txg
));
588 * TRUE if the current thread is the tx_sync_thread or if we
589 * are being called from SPA context during pool initialization.
592 dsl_pool_sync_context(dsl_pool_t
*dp
)
594 return (curthread
== dp
->dp_tx
.tx_sync_thread
||
595 spa_is_initializing(dp
->dp_spa
));
599 dsl_pool_adjustedsize(dsl_pool_t
*dp
, boolean_t netfree
)
601 uint64_t space
, resv
;
604 * Reserve about 1.6% (1/64), or at least 32MB, for allocation
606 * XXX The intent log is not accounted for, so it must fit
609 * If we're trying to assess whether it's OK to do a free,
610 * cut the reservation in half to allow forward progress
611 * (e.g. make it possible to rm(1) files from a full pool).
613 space
= spa_get_dspace(dp
->dp_spa
);
614 resv
= MAX(space
>> 6, SPA_MINDEVSIZE
>> 1);
618 return (space
- resv
);
622 dsl_pool_need_dirty_delay(dsl_pool_t
*dp
)
624 uint64_t delay_min_bytes
=
625 zfs_dirty_data_max
* zfs_delay_min_dirty_percent
/ 100;
628 mutex_enter(&dp
->dp_lock
);
629 if (dp
->dp_dirty_total
> zfs_dirty_data_sync
)
631 rv
= (dp
->dp_dirty_total
> delay_min_bytes
);
632 mutex_exit(&dp
->dp_lock
);
637 dsl_pool_dirty_space(dsl_pool_t
*dp
, int64_t space
, dmu_tx_t
*tx
)
640 mutex_enter(&dp
->dp_lock
);
641 dp
->dp_dirty_pertxg
[tx
->tx_txg
& TXG_MASK
] += space
;
642 dsl_pool_dirty_delta(dp
, space
);
643 mutex_exit(&dp
->dp_lock
);
648 dsl_pool_undirty_space(dsl_pool_t
*dp
, int64_t space
, uint64_t txg
)
650 ASSERT3S(space
, >=, 0);
654 mutex_enter(&dp
->dp_lock
);
655 if (dp
->dp_dirty_pertxg
[txg
& TXG_MASK
] < space
) {
656 /* XXX writing something we didn't dirty? */
657 space
= dp
->dp_dirty_pertxg
[txg
& TXG_MASK
];
659 ASSERT3U(dp
->dp_dirty_pertxg
[txg
& TXG_MASK
], >=, space
);
660 dp
->dp_dirty_pertxg
[txg
& TXG_MASK
] -= space
;
661 ASSERT3U(dp
->dp_dirty_total
, >=, space
);
662 dsl_pool_dirty_delta(dp
, -space
);
663 mutex_exit(&dp
->dp_lock
);
668 upgrade_clones_cb(dsl_pool_t
*dp
, dsl_dataset_t
*hds
, void *arg
)
671 dsl_dataset_t
*ds
, *prev
= NULL
;
674 err
= dsl_dataset_hold_obj(dp
, hds
->ds_object
, FTAG
, &ds
);
678 while (ds
->ds_phys
->ds_prev_snap_obj
!= 0) {
679 err
= dsl_dataset_hold_obj(dp
, ds
->ds_phys
->ds_prev_snap_obj
,
682 dsl_dataset_rele(ds
, FTAG
);
686 if (prev
->ds_phys
->ds_next_snap_obj
!= ds
->ds_object
)
688 dsl_dataset_rele(ds
, FTAG
);
694 prev
= dp
->dp_origin_snap
;
697 * The $ORIGIN can't have any data, or the accounting
700 ASSERT0(prev
->ds_phys
->ds_bp
.blk_birth
);
702 /* The origin doesn't get attached to itself */
703 if (ds
->ds_object
== prev
->ds_object
) {
704 dsl_dataset_rele(ds
, FTAG
);
708 dmu_buf_will_dirty(ds
->ds_dbuf
, tx
);
709 ds
->ds_phys
->ds_prev_snap_obj
= prev
->ds_object
;
710 ds
->ds_phys
->ds_prev_snap_txg
= prev
->ds_phys
->ds_creation_txg
;
712 dmu_buf_will_dirty(ds
->ds_dir
->dd_dbuf
, tx
);
713 ds
->ds_dir
->dd_phys
->dd_origin_obj
= prev
->ds_object
;
715 dmu_buf_will_dirty(prev
->ds_dbuf
, tx
);
716 prev
->ds_phys
->ds_num_children
++;
718 if (ds
->ds_phys
->ds_next_snap_obj
== 0) {
719 ASSERT(ds
->ds_prev
== NULL
);
720 VERIFY0(dsl_dataset_hold_obj(dp
,
721 ds
->ds_phys
->ds_prev_snap_obj
, ds
, &ds
->ds_prev
));
725 ASSERT3U(ds
->ds_dir
->dd_phys
->dd_origin_obj
, ==, prev
->ds_object
);
726 ASSERT3U(ds
->ds_phys
->ds_prev_snap_obj
, ==, prev
->ds_object
);
728 if (prev
->ds_phys
->ds_next_clones_obj
== 0) {
729 dmu_buf_will_dirty(prev
->ds_dbuf
, tx
);
730 prev
->ds_phys
->ds_next_clones_obj
=
731 zap_create(dp
->dp_meta_objset
,
732 DMU_OT_NEXT_CLONES
, DMU_OT_NONE
, 0, tx
);
734 VERIFY0(zap_add_int(dp
->dp_meta_objset
,
735 prev
->ds_phys
->ds_next_clones_obj
, ds
->ds_object
, tx
));
737 dsl_dataset_rele(ds
, FTAG
);
738 if (prev
!= dp
->dp_origin_snap
)
739 dsl_dataset_rele(prev
, FTAG
);
744 dsl_pool_upgrade_clones(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
746 ASSERT(dmu_tx_is_syncing(tx
));
747 ASSERT(dp
->dp_origin_snap
!= NULL
);
749 VERIFY0(dmu_objset_find_dp(dp
, dp
->dp_root_dir_obj
, upgrade_clones_cb
,
750 tx
, DS_FIND_CHILDREN
));
755 upgrade_dir_clones_cb(dsl_pool_t
*dp
, dsl_dataset_t
*ds
, void *arg
)
758 objset_t
*mos
= dp
->dp_meta_objset
;
760 if (ds
->ds_dir
->dd_phys
->dd_origin_obj
!= 0) {
761 dsl_dataset_t
*origin
;
763 VERIFY0(dsl_dataset_hold_obj(dp
,
764 ds
->ds_dir
->dd_phys
->dd_origin_obj
, FTAG
, &origin
));
766 if (origin
->ds_dir
->dd_phys
->dd_clones
== 0) {
767 dmu_buf_will_dirty(origin
->ds_dir
->dd_dbuf
, tx
);
768 origin
->ds_dir
->dd_phys
->dd_clones
= zap_create(mos
,
769 DMU_OT_DSL_CLONES
, DMU_OT_NONE
, 0, tx
);
772 VERIFY0(zap_add_int(dp
->dp_meta_objset
,
773 origin
->ds_dir
->dd_phys
->dd_clones
, ds
->ds_object
, tx
));
775 dsl_dataset_rele(origin
, FTAG
);
781 dsl_pool_upgrade_dir_clones(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
785 ASSERT(dmu_tx_is_syncing(tx
));
787 (void) dsl_dir_create_sync(dp
, dp
->dp_root_dir
, FREE_DIR_NAME
, tx
);
788 VERIFY0(dsl_pool_open_special_dir(dp
,
789 FREE_DIR_NAME
, &dp
->dp_free_dir
));
792 * We can't use bpobj_alloc(), because spa_version() still
793 * returns the old version, and we need a new-version bpobj with
794 * subobj support. So call dmu_object_alloc() directly.
796 obj
= dmu_object_alloc(dp
->dp_meta_objset
, DMU_OT_BPOBJ
,
797 SPA_MAXBLOCKSIZE
, DMU_OT_BPOBJ_HDR
, sizeof (bpobj_phys_t
), tx
);
798 VERIFY0(zap_add(dp
->dp_meta_objset
, DMU_POOL_DIRECTORY_OBJECT
,
799 DMU_POOL_FREE_BPOBJ
, sizeof (uint64_t), 1, &obj
, tx
));
800 VERIFY0(bpobj_open(&dp
->dp_free_bpobj
, dp
->dp_meta_objset
, obj
));
802 VERIFY0(dmu_objset_find_dp(dp
, dp
->dp_root_dir_obj
,
803 upgrade_dir_clones_cb
, tx
, DS_FIND_CHILDREN
));
807 dsl_pool_create_origin(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
812 ASSERT(dmu_tx_is_syncing(tx
));
813 ASSERT(dp
->dp_origin_snap
== NULL
);
814 ASSERT(rrw_held(&dp
->dp_config_rwlock
, RW_WRITER
));
816 /* create the origin dir, ds, & snap-ds */
817 dsobj
= dsl_dataset_create_sync(dp
->dp_root_dir
, ORIGIN_DIR_NAME
,
819 VERIFY0(dsl_dataset_hold_obj(dp
, dsobj
, FTAG
, &ds
));
820 dsl_dataset_snapshot_sync_impl(ds
, ORIGIN_DIR_NAME
, tx
);
821 VERIFY0(dsl_dataset_hold_obj(dp
, ds
->ds_phys
->ds_prev_snap_obj
,
822 dp
, &dp
->dp_origin_snap
));
823 dsl_dataset_rele(ds
, FTAG
);
827 dsl_pool_iput_taskq(dsl_pool_t
*dp
)
829 return (dp
->dp_iput_taskq
);
833 * Walk through the pool-wide zap object of temporary snapshot user holds
837 dsl_pool_clean_tmp_userrefs(dsl_pool_t
*dp
)
841 objset_t
*mos
= dp
->dp_meta_objset
;
842 uint64_t zapobj
= dp
->dp_tmp_userrefs_obj
;
847 ASSERT(spa_version(dp
->dp_spa
) >= SPA_VERSION_USERREFS
);
849 holds
= fnvlist_alloc();
851 for (zap_cursor_init(&zc
, mos
, zapobj
);
852 zap_cursor_retrieve(&zc
, &za
) == 0;
853 zap_cursor_advance(&zc
)) {
857 htag
= strchr(za
.za_name
, '-');
860 if (nvlist_lookup_nvlist(holds
, za
.za_name
, &tags
) != 0) {
861 tags
= fnvlist_alloc();
862 fnvlist_add_boolean(tags
, htag
);
863 fnvlist_add_nvlist(holds
, za
.za_name
, tags
);
866 fnvlist_add_boolean(tags
, htag
);
869 dsl_dataset_user_release_tmp(dp
, holds
);
871 zap_cursor_fini(&zc
);
875 * Create the pool-wide zap object for storing temporary snapshot holds.
878 dsl_pool_user_hold_create_obj(dsl_pool_t
*dp
, dmu_tx_t
*tx
)
880 objset_t
*mos
= dp
->dp_meta_objset
;
882 ASSERT(dp
->dp_tmp_userrefs_obj
== 0);
883 ASSERT(dmu_tx_is_syncing(tx
));
885 dp
->dp_tmp_userrefs_obj
= zap_create_link(mos
, DMU_OT_USERREFS
,
886 DMU_POOL_DIRECTORY_OBJECT
, DMU_POOL_TMP_USERREFS
, tx
);
890 dsl_pool_user_hold_rele_impl(dsl_pool_t
*dp
, uint64_t dsobj
,
891 const char *tag
, uint64_t now
, dmu_tx_t
*tx
, boolean_t holding
)
893 objset_t
*mos
= dp
->dp_meta_objset
;
894 uint64_t zapobj
= dp
->dp_tmp_userrefs_obj
;
898 ASSERT(spa_version(dp
->dp_spa
) >= SPA_VERSION_USERREFS
);
899 ASSERT(dmu_tx_is_syncing(tx
));
902 * If the pool was created prior to SPA_VERSION_USERREFS, the
903 * zap object for temporary holds might not exist yet.
907 dsl_pool_user_hold_create_obj(dp
, tx
);
908 zapobj
= dp
->dp_tmp_userrefs_obj
;
910 return (SET_ERROR(ENOENT
));
914 name
= kmem_asprintf("%llx-%s", (u_longlong_t
)dsobj
, tag
);
916 error
= zap_add(mos
, zapobj
, name
, 8, 1, &now
, tx
);
918 error
= zap_remove(mos
, zapobj
, name
, tx
);
925 * Add a temporary hold for the given dataset object and tag.
928 dsl_pool_user_hold(dsl_pool_t
*dp
, uint64_t dsobj
, const char *tag
,
929 uint64_t now
, dmu_tx_t
*tx
)
931 return (dsl_pool_user_hold_rele_impl(dp
, dsobj
, tag
, now
, tx
, B_TRUE
));
935 * Release a temporary hold for the given dataset object and tag.
938 dsl_pool_user_release(dsl_pool_t
*dp
, uint64_t dsobj
, const char *tag
,
941 return (dsl_pool_user_hold_rele_impl(dp
, dsobj
, tag
, 0,
946 * DSL Pool Configuration Lock
948 * The dp_config_rwlock protects against changes to DSL state (e.g. dataset
949 * creation / destruction / rename / property setting). It must be held for
950 * read to hold a dataset or dsl_dir. I.e. you must call
951 * dsl_pool_config_enter() or dsl_pool_hold() before calling
952 * dsl_{dataset,dir}_hold{_obj}. In most circumstances, the dp_config_rwlock
953 * must be held continuously until all datasets and dsl_dirs are released.
955 * The only exception to this rule is that if a "long hold" is placed on
956 * a dataset, then the dp_config_rwlock may be dropped while the dataset
957 * is still held. The long hold will prevent the dataset from being
958 * destroyed -- the destroy will fail with EBUSY. A long hold can be
959 * obtained by calling dsl_dataset_long_hold(), or by "owning" a dataset
960 * (by calling dsl_{dataset,objset}_{try}own{_obj}).
962 * Legitimate long-holders (including owners) should be long-running, cancelable
963 * tasks that should cause "zfs destroy" to fail. This includes DMU
964 * consumers (i.e. a ZPL filesystem being mounted or ZVOL being open),
965 * "zfs send", and "zfs diff". There are several other long-holders whose
966 * uses are suboptimal (e.g. "zfs promote", and zil_suspend()).
968 * The usual formula for long-holding would be:
971 * ... perform checks ...
972 * dsl_dataset_long_hold()
974 * ... perform long-running task ...
975 * dsl_dataset_long_rele()
978 * Note that when the long hold is released, the dataset is still held but
979 * the pool is not held. The dataset may change arbitrarily during this time
980 * (e.g. it could be destroyed). Therefore you shouldn't do anything to the
981 * dataset except release it.
983 * User-initiated operations (e.g. ioctls, zfs_ioc_*()) are either read-only
984 * or modifying operations.
986 * Modifying operations should generally use dsl_sync_task(). The synctask
987 * infrastructure enforces proper locking strategy with respect to the
988 * dp_config_rwlock. See the comment above dsl_sync_task() for details.
990 * Read-only operations will manually hold the pool, then the dataset, obtain
991 * information from the dataset, then release the pool and dataset.
992 * dmu_objset_{hold,rele}() are convenience routines that also do the pool
997 dsl_pool_hold(const char *name
, void *tag
, dsl_pool_t
**dp
)
1002 error
= spa_open(name
, &spa
, tag
);
1004 *dp
= spa_get_dsl(spa
);
1005 dsl_pool_config_enter(*dp
, tag
);
1011 dsl_pool_rele(dsl_pool_t
*dp
, void *tag
)
1013 dsl_pool_config_exit(dp
, tag
);
1014 spa_close(dp
->dp_spa
, tag
);
1018 dsl_pool_config_enter(dsl_pool_t
*dp
, void *tag
)
1021 * We use a "reentrant" reader-writer lock, but not reentrantly.
1023 * The rrwlock can (with the track_all flag) track all reading threads,
1024 * which is very useful for debugging which code path failed to release
1025 * the lock, and for verifying that the *current* thread does hold
1028 * (Unlike a rwlock, which knows that N threads hold it for
1029 * read, but not *which* threads, so rw_held(RW_READER) returns TRUE
1030 * if any thread holds it for read, even if this thread doesn't).
1032 ASSERT(!rrw_held(&dp
->dp_config_rwlock
, RW_READER
));
1033 rrw_enter(&dp
->dp_config_rwlock
, RW_READER
, tag
);
1037 dsl_pool_config_exit(dsl_pool_t
*dp
, void *tag
)
1039 rrw_exit(&dp
->dp_config_rwlock
, tag
);
1043 dsl_pool_config_held(dsl_pool_t
*dp
)
1045 return (RRW_LOCK_HELD(&dp
->dp_config_rwlock
));
1048 #if defined(_KERNEL) && defined(HAVE_SPL)
1049 EXPORT_SYMBOL(dsl_pool_config_enter
);
1050 EXPORT_SYMBOL(dsl_pool_config_exit
);
1052 /* zfs_dirty_data_max_percent only applied at module load time in arc_init(). */
1053 module_param(zfs_dirty_data_max_percent
, int, 0444);
1054 MODULE_PARM_DESC(zfs_dirty_data_max_percent
, "percent of ram can be dirty");
1056 /* zfs_dirty_data_max_max_percent only applied at module load time in
1058 module_param(zfs_dirty_data_max_max_percent
, int, 0444);
1059 MODULE_PARM_DESC(zfs_dirty_data_max_max_percent
,
1060 "zfs_dirty_data_max upper bound as % of RAM");
1062 module_param(zfs_delay_min_dirty_percent
, int, 0644);
1063 MODULE_PARM_DESC(zfs_delay_min_dirty_percent
, "transaction delay threshold");
1065 module_param(zfs_dirty_data_max
, ulong
, 0644);
1066 MODULE_PARM_DESC(zfs_dirty_data_max
, "determines the dirty space limit");
1068 /* zfs_dirty_data_max_max only applied at module load time in arc_init(). */
1069 module_param(zfs_dirty_data_max_max
, ulong
, 0444);
1070 MODULE_PARM_DESC(zfs_dirty_data_max_max
,
1071 "zfs_dirty_data_max upper bound in bytes");
1073 module_param(zfs_dirty_data_sync
, ulong
, 0644);
1074 MODULE_PARM_DESC(zfs_dirty_data_sync
, "sync txg when this much dirty data");
1076 module_param(zfs_delay_scale
, ulong
, 0644);
1077 MODULE_PARM_DESC(zfs_delay_scale
, "how quickly delay approaches infinity");