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) 2012 by Delphix. All rights reserved.
26 #include <sys/dsl_pool.h>
27 #include <sys/dsl_dataset.h>
28 #include <sys/dsl_prop.h>
29 #include <sys/dsl_dir.h>
30 #include <sys/dsl_synctask.h>
31 #include <sys/dsl_scan.h>
32 #include <sys/dnode.h>
33 #include <sys/dmu_tx.h>
34 #include <sys/dmu_objset.h>
38 #include <sys/zfs_context.h>
39 #include <sys/fs/zfs.h>
40 #include <sys/zfs_znode.h>
41 #include <sys/spa_impl.h>
42 #include <sys/dsl_deadlist.h>
43 #include <sys/bptree.h>
44 #include <sys/zfeature.h>
45 #include <sys/zil_impl.h>
47 int zfs_no_write_throttle = 0;
48 int zfs_write_limit_shift = 3; /* 1/8th of physical memory */
49 int zfs_txg_synctime_ms = 1000; /* target millisecs to sync a txg */
50 int zfs_txg_history = 60; /* statistics for the last N txgs */
52 unsigned long zfs_write_limit_min = 32 << 20; /* min write limit is 32MB */
53 unsigned long zfs_write_limit_max = 0; /* max data payload per txg */
54 unsigned long zfs_write_limit_inflated = 0;
55 unsigned long zfs_write_limit_override = 0;
57 kmutex_t zfs_write_limit_lock;
59 static pgcnt_t old_physmem = 0;
62 dsl_pool_tx_assign_init(dsl_pool_t *dp, unsigned int ndata)
65 char name[KSTAT_STRLEN];
66 int i, data_size = ndata * sizeof(kstat_named_t);
68 (void) snprintf(name, KSTAT_STRLEN, "dmu_tx_assign-%s",
69 spa_name(dp->dp_spa));
71 dp->dp_tx_assign_size = ndata;
74 dp->dp_tx_assign_buckets = kmem_alloc(data_size, KM_SLEEP);
76 dp->dp_tx_assign_buckets = NULL;
78 for (i = 0; i < dp->dp_tx_assign_size; i++) {
79 ks = &dp->dp_tx_assign_buckets[i];
80 ks->data_type = KSTAT_DATA_UINT64;
82 (void) snprintf(ks->name, KSTAT_STRLEN, "%u us", 1 << i);
85 dp->dp_tx_assign_kstat = kstat_create("zfs", 0, name, "misc",
86 KSTAT_TYPE_NAMED, 0, KSTAT_FLAG_VIRTUAL);
88 if (dp->dp_tx_assign_kstat) {
89 dp->dp_tx_assign_kstat->ks_data = dp->dp_tx_assign_buckets;
90 dp->dp_tx_assign_kstat->ks_ndata = dp->dp_tx_assign_size;
91 dp->dp_tx_assign_kstat->ks_data_size = data_size;
92 kstat_install(dp->dp_tx_assign_kstat);
97 dsl_pool_tx_assign_destroy(dsl_pool_t *dp)
99 if (dp->dp_tx_assign_buckets)
100 kmem_free(dp->dp_tx_assign_buckets,
101 dp->dp_tx_assign_size * sizeof(kstat_named_t));
103 if (dp->dp_tx_assign_kstat)
104 kstat_delete(dp->dp_tx_assign_kstat);
108 dsl_pool_tx_assign_add_usecs(dsl_pool_t *dp, uint64_t usecs)
112 while (((1 << idx) < usecs) && (idx < dp->dp_tx_assign_size - 1))
115 atomic_inc_64(&dp->dp_tx_assign_buckets[idx].value.ui64);
119 dsl_pool_txg_history_update(kstat_t *ksp, int rw)
121 dsl_pool_t *dp = ksp->ks_private;
125 if (rw == KSTAT_WRITE)
129 kmem_free(ksp->ks_data, ksp->ks_data_size);
131 mutex_enter(&dp->dp_lock);
133 ksp->ks_ndata = dp->dp_txg_history_size;
134 ksp->ks_data_size = dp->dp_txg_history_size * sizeof(kstat_txg_t);
135 if (ksp->ks_data_size > 0)
136 ksp->ks_data = kmem_alloc(ksp->ks_data_size, KM_PUSHPAGE);
138 /* Traversed oldest to youngest for the most readable kstat output */
139 for (th = list_tail(&dp->dp_txg_history); th != NULL;
140 th = list_prev(&dp->dp_txg_history, th)) {
141 mutex_enter(&th->th_lock);
142 ASSERT3S(i + sizeof(kstat_txg_t), <=, ksp->ks_data_size);
143 memcpy(ksp->ks_data + i, &th->th_kstat, sizeof(kstat_txg_t));
144 i += sizeof(kstat_txg_t);
145 mutex_exit(&th->th_lock);
148 mutex_exit(&dp->dp_lock);
154 dsl_pool_txg_history_init(dsl_pool_t *dp, uint64_t txg)
156 char name[KSTAT_STRLEN];
158 list_create(&dp->dp_txg_history, sizeof (txg_history_t),
159 offsetof(txg_history_t, th_link));
160 dsl_pool_txg_history_add(dp, txg);
162 (void) snprintf(name, KSTAT_STRLEN, "txgs-%s", spa_name(dp->dp_spa));
163 dp->dp_txg_kstat = kstat_create("zfs", 0, name, "misc",
164 KSTAT_TYPE_TXG, 0, KSTAT_FLAG_VIRTUAL);
165 if (dp->dp_txg_kstat) {
166 dp->dp_txg_kstat->ks_data = NULL;
167 dp->dp_txg_kstat->ks_private = dp;
168 dp->dp_txg_kstat->ks_update = dsl_pool_txg_history_update;
169 kstat_install(dp->dp_txg_kstat);
174 dsl_pool_txg_history_destroy(dsl_pool_t *dp)
178 if (dp->dp_txg_kstat) {
179 if (dp->dp_txg_kstat->ks_data)
180 kmem_free(dp->dp_txg_kstat->ks_data,
181 dp->dp_txg_kstat->ks_data_size);
183 kstat_delete(dp->dp_txg_kstat);
186 mutex_enter(&dp->dp_lock);
187 while ((th = list_remove_head(&dp->dp_txg_history))) {
188 dp->dp_txg_history_size--;
189 mutex_destroy(&th->th_lock);
190 kmem_free(th, sizeof(txg_history_t));
193 ASSERT3U(dp->dp_txg_history_size, ==, 0);
194 list_destroy(&dp->dp_txg_history);
195 mutex_exit(&dp->dp_lock);
199 dsl_pool_txg_history_add(dsl_pool_t *dp, uint64_t txg)
201 txg_history_t *th, *rm;
203 th = kmem_zalloc(sizeof(txg_history_t), KM_PUSHPAGE);
204 mutex_init(&th->th_lock, NULL, MUTEX_DEFAULT, NULL);
205 th->th_kstat.txg = txg;
206 th->th_kstat.state = TXG_STATE_OPEN;
207 th->th_kstat.birth = gethrtime();
209 mutex_enter(&dp->dp_lock);
211 list_insert_head(&dp->dp_txg_history, th);
212 dp->dp_txg_history_size++;
214 while (dp->dp_txg_history_size > zfs_txg_history) {
215 dp->dp_txg_history_size--;
216 rm = list_remove_tail(&dp->dp_txg_history);
217 mutex_destroy(&rm->th_lock);
218 kmem_free(rm, sizeof(txg_history_t));
221 mutex_exit(&dp->dp_lock);
227 * Traversed youngest to oldest because lookups are only done for open
228 * or syncing txgs which are guaranteed to be at the head of the list.
229 * The txg_history_t structure will be returned locked.
232 dsl_pool_txg_history_get(dsl_pool_t *dp, uint64_t txg)
236 mutex_enter(&dp->dp_lock);
237 for (th = list_head(&dp->dp_txg_history); th != NULL;
238 th = list_next(&dp->dp_txg_history, th)) {
239 if (th->th_kstat.txg == txg) {
240 mutex_enter(&th->th_lock);
244 mutex_exit(&dp->dp_lock);
250 dsl_pool_txg_history_put(txg_history_t *th)
252 mutex_exit(&th->th_lock);
256 dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
261 err = zap_lookup(dp->dp_meta_objset,
262 dp->dp_root_dir->dd_phys->dd_child_dir_zapobj,
263 name, sizeof (obj), 1, &obj);
267 return (dsl_dir_open_obj(dp, obj, name, dp, ddp));
271 dsl_pool_open_impl(spa_t *spa, uint64_t txg)
274 blkptr_t *bp = spa_get_rootblkptr(spa);
276 dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
278 dp->dp_meta_rootbp = *bp;
279 rw_init(&dp->dp_config_rwlock, NULL, RW_DEFAULT, NULL);
280 dp->dp_write_limit = zfs_write_limit_min;
283 txg_list_create(&dp->dp_dirty_datasets,
284 offsetof(dsl_dataset_t, ds_dirty_link));
285 txg_list_create(&dp->dp_dirty_zilogs,
286 offsetof(zilog_t, zl_dirty_link));
287 txg_list_create(&dp->dp_dirty_dirs,
288 offsetof(dsl_dir_t, dd_dirty_link));
289 txg_list_create(&dp->dp_sync_tasks,
290 offsetof(dsl_sync_task_group_t, dstg_node));
292 mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
294 dp->dp_iput_taskq = taskq_create("zfs_iput_taskq", 1, minclsyspri,
297 dsl_pool_txg_history_init(dp, txg);
298 dsl_pool_tx_assign_init(dp, 32);
304 dsl_pool_init(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
307 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
309 err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,
310 &dp->dp_meta_objset);
320 dsl_pool_open(dsl_pool_t *dp)
327 rw_enter(&dp->dp_config_rwlock, RW_WRITER);
328 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
329 DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
330 &dp->dp_root_dir_obj);
334 err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
335 NULL, dp, &dp->dp_root_dir);
339 err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir);
343 if (spa_version(dp->dp_spa) >= SPA_VERSION_ORIGIN) {
344 err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd);
347 err = dsl_dataset_hold_obj(dp, dd->dd_phys->dd_head_dataset_obj,
350 err = dsl_dataset_hold_obj(dp,
351 ds->ds_phys->ds_prev_snap_obj, dp,
352 &dp->dp_origin_snap);
353 dsl_dataset_rele(ds, FTAG);
355 dsl_dir_close(dd, dp);
360 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
361 err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME,
366 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
367 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj);
370 VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
371 dp->dp_meta_objset, obj));
374 if (spa_feature_is_active(dp->dp_spa,
375 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
376 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
377 DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
383 if (spa_feature_is_active(dp->dp_spa,
384 &spa_feature_table[SPA_FEATURE_EMPTY_BPOBJ])) {
385 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
386 DMU_POOL_EMPTY_BPOBJ, sizeof (uint64_t), 1,
387 &dp->dp_empty_bpobj);
392 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
393 DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
394 &dp->dp_tmp_userrefs_obj);
400 err = dsl_scan_init(dp, dp->dp_tx.tx_open_txg);
403 rw_exit(&dp->dp_config_rwlock);
408 dsl_pool_close(dsl_pool_t *dp)
410 /* drop our references from dsl_pool_open() */
413 * Since we held the origin_snap from "syncing" context (which
414 * includes pool-opening context), it actually only got a "ref"
415 * and not a hold, so just drop that here.
417 if (dp->dp_origin_snap)
418 dsl_dataset_drop_ref(dp->dp_origin_snap, dp);
420 dsl_dir_close(dp->dp_mos_dir, dp);
422 dsl_dir_close(dp->dp_free_dir, dp);
424 dsl_dir_close(dp->dp_root_dir, dp);
426 bpobj_close(&dp->dp_free_bpobj);
428 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
429 if (dp->dp_meta_objset)
430 dmu_objset_evict(dp->dp_meta_objset);
432 txg_list_destroy(&dp->dp_dirty_datasets);
433 txg_list_destroy(&dp->dp_dirty_zilogs);
434 txg_list_destroy(&dp->dp_sync_tasks);
435 txg_list_destroy(&dp->dp_dirty_dirs);
437 arc_flush(dp->dp_spa);
440 dsl_pool_tx_assign_destroy(dp);
441 dsl_pool_txg_history_destroy(dp);
442 rw_destroy(&dp->dp_config_rwlock);
443 mutex_destroy(&dp->dp_lock);
444 taskq_destroy(dp->dp_iput_taskq);
446 kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
447 kmem_free(dp, sizeof (dsl_pool_t));
451 dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)
454 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
455 dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
460 /* create and open the MOS (meta-objset) */
461 dp->dp_meta_objset = dmu_objset_create_impl(spa,
462 NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);
464 /* create the pool directory */
465 err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
466 DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
469 /* Initialize scan structures */
470 VERIFY3U(0, ==, dsl_scan_init(dp, txg));
472 /* create and open the root dir */
473 dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);
474 VERIFY(0 == dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
475 NULL, dp, &dp->dp_root_dir));
477 /* create and open the meta-objset dir */
478 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);
479 VERIFY(0 == dsl_pool_open_special_dir(dp,
480 MOS_DIR_NAME, &dp->dp_mos_dir));
482 if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
483 /* create and open the free dir */
484 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
486 VERIFY(0 == dsl_pool_open_special_dir(dp,
487 FREE_DIR_NAME, &dp->dp_free_dir));
489 /* create and open the free_bplist */
490 obj = bpobj_alloc(dp->dp_meta_objset, SPA_MAXBLOCKSIZE, tx);
491 VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
492 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0);
493 VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
494 dp->dp_meta_objset, obj));
497 if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB)
498 dsl_pool_create_origin(dp, tx);
500 /* create the root dataset */
501 obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);
503 /* create the root objset */
504 VERIFY(0 == dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
505 VERIFY(NULL != (os = dmu_objset_create_impl(dp->dp_spa, ds,
506 dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx)));
508 zfs_create_fs(os, kcred, zplprops, tx);
510 dsl_dataset_rele(ds, FTAG);
518 * Account for the meta-objset space in its placeholder dsl_dir.
521 dsl_pool_mos_diduse_space(dsl_pool_t *dp,
522 int64_t used, int64_t comp, int64_t uncomp)
524 ASSERT3U(comp, ==, uncomp); /* it's all metadata */
525 mutex_enter(&dp->dp_lock);
526 dp->dp_mos_used_delta += used;
527 dp->dp_mos_compressed_delta += comp;
528 dp->dp_mos_uncompressed_delta += uncomp;
529 mutex_exit(&dp->dp_lock);
533 deadlist_enqueue_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
535 dsl_deadlist_t *dl = arg;
536 dsl_pool_t *dp = dmu_objset_pool(dl->dl_os);
537 rw_enter(&dp->dp_config_rwlock, RW_READER);
538 dsl_deadlist_insert(dl, bp, tx);
539 rw_exit(&dp->dp_config_rwlock);
544 dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
550 objset_t *mos = dp->dp_meta_objset;
551 hrtime_t start, write_time;
552 uint64_t data_written;
554 list_t synced_datasets;
556 list_create(&synced_datasets, sizeof (dsl_dataset_t),
557 offsetof(dsl_dataset_t, ds_synced_link));
560 * We need to copy dp_space_towrite() before doing
561 * dsl_sync_task_group_sync(), because
562 * dsl_dataset_snapshot_reserve_space() will increase
563 * dp_space_towrite but not actually write anything.
565 data_written = dp->dp_space_towrite[txg & TXG_MASK];
567 tx = dmu_tx_create_assigned(dp, txg);
569 dp->dp_read_overhead = 0;
572 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
573 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg))) {
575 * We must not sync any non-MOS datasets twice, because
576 * we may have taken a snapshot of them. However, we
577 * may sync newly-created datasets on pass 2.
579 ASSERT(!list_link_active(&ds->ds_synced_link));
580 list_insert_tail(&synced_datasets, ds);
581 dsl_dataset_sync(ds, zio, tx);
583 DTRACE_PROBE(pool_sync__1setup);
586 write_time = gethrtime() - start;
588 DTRACE_PROBE(pool_sync__2rootzio);
591 * After the data blocks have been written (ensured by the zio_wait()
592 * above), update the user/group space accounting.
594 for (ds = list_head(&synced_datasets); ds;
595 ds = list_next(&synced_datasets, ds))
596 dmu_objset_do_userquota_updates(ds->ds_objset, tx);
599 * Sync the datasets again to push out the changes due to
600 * userspace updates. This must be done before we process the
601 * sync tasks, so that any snapshots will have the correct
602 * user accounting information (and we won't get confused
603 * about which blocks are part of the snapshot).
605 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
606 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg))) {
607 ASSERT(list_link_active(&ds->ds_synced_link));
608 dmu_buf_rele(ds->ds_dbuf, ds);
609 dsl_dataset_sync(ds, zio, tx);
614 * Now that the datasets have been completely synced, we can
615 * clean up our in-memory structures accumulated while syncing:
617 * - move dead blocks from the pending deadlist to the on-disk deadlist
618 * - clean up zil records
619 * - release hold from dsl_dataset_dirty()
621 while ((ds = list_remove_head(&synced_datasets))) {
622 ASSERTV(objset_t *os = ds->ds_objset);
623 bplist_iterate(&ds->ds_pending_deadlist,
624 deadlist_enqueue_cb, &ds->ds_deadlist, tx);
625 ASSERT(!dmu_objset_is_dirty(os, txg));
626 dmu_buf_rele(ds->ds_dbuf, ds);
630 while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)))
631 dsl_dir_sync(dd, tx);
632 write_time += gethrtime() - start;
635 * The MOS's space is accounted for in the pool/$MOS
636 * (dp_mos_dir). We can't modify the mos while we're syncing
637 * it, so we remember the deltas and apply them here.
639 if (dp->dp_mos_used_delta != 0 || dp->dp_mos_compressed_delta != 0 ||
640 dp->dp_mos_uncompressed_delta != 0) {
641 dsl_dir_diduse_space(dp->dp_mos_dir, DD_USED_HEAD,
642 dp->dp_mos_used_delta,
643 dp->dp_mos_compressed_delta,
644 dp->dp_mos_uncompressed_delta, tx);
645 dp->dp_mos_used_delta = 0;
646 dp->dp_mos_compressed_delta = 0;
647 dp->dp_mos_uncompressed_delta = 0;
651 if (list_head(&mos->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||
652 list_head(&mos->os_free_dnodes[txg & TXG_MASK]) != NULL) {
653 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
654 dmu_objset_sync(mos, zio, tx);
657 dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
658 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
660 write_time += gethrtime() - start;
661 DTRACE_PROBE2(pool_sync__4io, hrtime_t, write_time,
662 hrtime_t, dp->dp_read_overhead);
663 write_time -= dp->dp_read_overhead;
666 * If we modify a dataset in the same txg that we want to destroy it,
667 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
668 * dsl_dir_destroy_check() will fail if there are unexpected holds.
669 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
670 * and clearing the hold on it) before we process the sync_tasks.
671 * The MOS data dirtied by the sync_tasks will be synced on the next
674 DTRACE_PROBE(pool_sync__3task);
675 if (!txg_list_empty(&dp->dp_sync_tasks, txg)) {
676 dsl_sync_task_group_t *dstg;
678 * No more sync tasks should have been added while we
681 ASSERT(spa_sync_pass(dp->dp_spa) == 1);
682 while ((dstg = txg_list_remove(&dp->dp_sync_tasks, txg)))
683 dsl_sync_task_group_sync(dstg, tx);
688 dp->dp_space_towrite[txg & TXG_MASK] = 0;
689 ASSERT(dp->dp_tempreserved[txg & TXG_MASK] == 0);
692 * If the write limit max has not been explicitly set, set it
693 * to a fraction of available physical memory (default 1/8th).
694 * Note that we must inflate the limit because the spa
695 * inflates write sizes to account for data replication.
696 * Check this each sync phase to catch changing memory size.
698 if (physmem != old_physmem && zfs_write_limit_shift) {
699 mutex_enter(&zfs_write_limit_lock);
700 old_physmem = physmem;
701 zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift;
702 zfs_write_limit_inflated = MAX(zfs_write_limit_min,
703 spa_get_asize(dp->dp_spa, zfs_write_limit_max));
704 mutex_exit(&zfs_write_limit_lock);
708 * Attempt to keep the sync time consistent by adjusting the
709 * amount of write traffic allowed into each transaction group.
710 * Weight the throughput calculation towards the current value:
711 * thru = 3/4 old_thru + 1/4 new_thru
713 * Note: write_time is in nanosecs, so write_time/MICROSEC
716 ASSERT(zfs_write_limit_min > 0);
717 if (data_written > zfs_write_limit_min / 8 && write_time > MICROSEC) {
718 uint64_t throughput = data_written / (write_time / MICROSEC);
720 if (dp->dp_throughput)
721 dp->dp_throughput = throughput / 4 +
722 3 * dp->dp_throughput / 4;
724 dp->dp_throughput = throughput;
725 dp->dp_write_limit = MIN(zfs_write_limit_inflated,
726 MAX(zfs_write_limit_min,
727 dp->dp_throughput * zfs_txg_synctime_ms));
732 dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)
737 while ((zilog = txg_list_remove(&dp->dp_dirty_zilogs, txg))) {
738 ds = dmu_objset_ds(zilog->zl_os);
739 zil_clean(zilog, txg);
740 ASSERT(!dmu_objset_is_dirty(zilog->zl_os, txg));
741 dmu_buf_rele(ds->ds_dbuf, zilog);
743 ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));
747 * TRUE if the current thread is the tx_sync_thread or if we
748 * are being called from SPA context during pool initialization.
751 dsl_pool_sync_context(dsl_pool_t *dp)
753 return (curthread == dp->dp_tx.tx_sync_thread ||
754 spa_is_initializing(dp->dp_spa));
758 dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree)
760 uint64_t space, resv;
763 * Reserve about 1.6% (1/64), or at least 32MB, for allocation
765 * XXX The intent log is not accounted for, so it must fit
768 * If we're trying to assess whether it's OK to do a free,
769 * cut the reservation in half to allow forward progress
770 * (e.g. make it possible to rm(1) files from a full pool).
772 space = spa_get_dspace(dp->dp_spa);
773 resv = MAX(space >> 6, SPA_MINDEVSIZE >> 1);
777 return (space - resv);
781 dsl_pool_tempreserve_space(dsl_pool_t *dp, uint64_t space, dmu_tx_t *tx)
783 uint64_t reserved = 0;
784 uint64_t write_limit = (zfs_write_limit_override ?
785 zfs_write_limit_override : dp->dp_write_limit);
787 if (zfs_no_write_throttle) {
788 atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK],
794 * Check to see if we have exceeded the maximum allowed IO for
795 * this transaction group. We can do this without locks since
796 * a little slop here is ok. Note that we do the reserved check
797 * with only half the requested reserve: this is because the
798 * reserve requests are worst-case, and we really don't want to
799 * throttle based off of worst-case estimates.
801 if (write_limit > 0) {
802 reserved = dp->dp_space_towrite[tx->tx_txg & TXG_MASK]
803 + dp->dp_tempreserved[tx->tx_txg & TXG_MASK] / 2;
805 if (reserved && reserved > write_limit) {
806 DMU_TX_STAT_BUMP(dmu_tx_write_limit);
811 atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], space);
814 * If this transaction group is over 7/8ths capacity, delay
815 * the caller 1 clock tick. This will slow down the "fill"
816 * rate until the sync process can catch up with us.
818 if (reserved && reserved > (write_limit - (write_limit >> 3)))
819 txg_delay(dp, tx->tx_txg, 1);
825 dsl_pool_tempreserve_clear(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
827 ASSERT(dp->dp_tempreserved[tx->tx_txg & TXG_MASK] >= space);
828 atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], -space);
832 dsl_pool_memory_pressure(dsl_pool_t *dp)
834 uint64_t space_inuse = 0;
837 if (dp->dp_write_limit == zfs_write_limit_min)
840 for (i = 0; i < TXG_SIZE; i++) {
841 space_inuse += dp->dp_space_towrite[i];
842 space_inuse += dp->dp_tempreserved[i];
844 dp->dp_write_limit = MAX(zfs_write_limit_min,
845 MIN(dp->dp_write_limit, space_inuse / 4));
849 dsl_pool_willuse_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
852 mutex_enter(&dp->dp_lock);
853 dp->dp_space_towrite[tx->tx_txg & TXG_MASK] += space;
854 mutex_exit(&dp->dp_lock);
860 upgrade_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
863 dsl_dataset_t *ds, *prev = NULL;
865 dsl_pool_t *dp = spa_get_dsl(spa);
867 err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
871 while (ds->ds_phys->ds_prev_snap_obj != 0) {
872 err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
875 dsl_dataset_rele(ds, FTAG);
879 if (prev->ds_phys->ds_next_snap_obj != ds->ds_object)
881 dsl_dataset_rele(ds, FTAG);
887 prev = dp->dp_origin_snap;
890 * The $ORIGIN can't have any data, or the accounting
893 ASSERT(prev->ds_phys->ds_bp.blk_birth == 0);
895 /* The origin doesn't get attached to itself */
896 if (ds->ds_object == prev->ds_object) {
897 dsl_dataset_rele(ds, FTAG);
901 dmu_buf_will_dirty(ds->ds_dbuf, tx);
902 ds->ds_phys->ds_prev_snap_obj = prev->ds_object;
903 ds->ds_phys->ds_prev_snap_txg = prev->ds_phys->ds_creation_txg;
905 dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
906 ds->ds_dir->dd_phys->dd_origin_obj = prev->ds_object;
908 dmu_buf_will_dirty(prev->ds_dbuf, tx);
909 prev->ds_phys->ds_num_children++;
911 if (ds->ds_phys->ds_next_snap_obj == 0) {
912 ASSERT(ds->ds_prev == NULL);
913 VERIFY(0 == dsl_dataset_hold_obj(dp,
914 ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev));
918 ASSERT(ds->ds_dir->dd_phys->dd_origin_obj == prev->ds_object);
919 ASSERT(ds->ds_phys->ds_prev_snap_obj == prev->ds_object);
921 if (prev->ds_phys->ds_next_clones_obj == 0) {
922 dmu_buf_will_dirty(prev->ds_dbuf, tx);
923 prev->ds_phys->ds_next_clones_obj =
924 zap_create(dp->dp_meta_objset,
925 DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
927 VERIFY(0 == zap_add_int(dp->dp_meta_objset,
928 prev->ds_phys->ds_next_clones_obj, ds->ds_object, tx));
930 dsl_dataset_rele(ds, FTAG);
931 if (prev != dp->dp_origin_snap)
932 dsl_dataset_rele(prev, FTAG);
937 dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx)
939 ASSERT(dmu_tx_is_syncing(tx));
940 ASSERT(dp->dp_origin_snap != NULL);
942 VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL, upgrade_clones_cb,
943 tx, DS_FIND_CHILDREN));
948 upgrade_dir_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
952 dsl_pool_t *dp = spa_get_dsl(spa);
953 objset_t *mos = dp->dp_meta_objset;
955 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
957 if (ds->ds_dir->dd_phys->dd_origin_obj) {
958 dsl_dataset_t *origin;
960 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp,
961 ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin));
963 if (origin->ds_dir->dd_phys->dd_clones == 0) {
964 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
965 origin->ds_dir->dd_phys->dd_clones = zap_create(mos,
966 DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
969 VERIFY3U(0, ==, zap_add_int(dp->dp_meta_objset,
970 origin->ds_dir->dd_phys->dd_clones, dsobj, tx));
972 dsl_dataset_rele(origin, FTAG);
975 dsl_dataset_rele(ds, FTAG);
980 dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx)
984 ASSERT(dmu_tx_is_syncing(tx));
986 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx);
987 VERIFY(0 == dsl_pool_open_special_dir(dp,
988 FREE_DIR_NAME, &dp->dp_free_dir));
991 * We can't use bpobj_alloc(), because spa_version() still
992 * returns the old version, and we need a new-version bpobj with
993 * subobj support. So call dmu_object_alloc() directly.
995 obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ,
996 SPA_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx);
997 VERIFY3U(0, ==, zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
998 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
999 VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
1000 dp->dp_meta_objset, obj));
1002 VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL,
1003 upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN));
1007 dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
1012 ASSERT(dmu_tx_is_syncing(tx));
1013 ASSERT(dp->dp_origin_snap == NULL);
1015 /* create the origin dir, ds, & snap-ds */
1016 rw_enter(&dp->dp_config_rwlock, RW_WRITER);
1017 dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME,
1018 NULL, 0, kcred, tx);
1019 VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
1020 dsl_dataset_snapshot_sync(ds, ORIGIN_DIR_NAME, tx);
1021 VERIFY(0 == dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
1022 dp, &dp->dp_origin_snap));
1023 dsl_dataset_rele(ds, FTAG);
1024 rw_exit(&dp->dp_config_rwlock);
1028 dsl_pool_iput_taskq(dsl_pool_t *dp)
1030 return (dp->dp_iput_taskq);
1034 * Walk through the pool-wide zap object of temporary snapshot user holds
1038 dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp)
1042 objset_t *mos = dp->dp_meta_objset;
1043 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
1047 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
1049 for (zap_cursor_init(&zc, mos, zapobj);
1050 zap_cursor_retrieve(&zc, &za) == 0;
1051 zap_cursor_advance(&zc)) {
1055 htag = strchr(za.za_name, '-');
1058 dsobj = strtonum(za.za_name, NULL);
1059 (void) dsl_dataset_user_release_tmp(dp, dsobj, htag, B_FALSE);
1061 zap_cursor_fini(&zc);
1065 * Create the pool-wide zap object for storing temporary snapshot holds.
1068 dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx)
1070 objset_t *mos = dp->dp_meta_objset;
1072 ASSERT(dp->dp_tmp_userrefs_obj == 0);
1073 ASSERT(dmu_tx_is_syncing(tx));
1075 dp->dp_tmp_userrefs_obj = zap_create_link(mos, DMU_OT_USERREFS,
1076 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS, tx);
1080 dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj,
1081 const char *tag, uint64_t *now, dmu_tx_t *tx, boolean_t holding)
1083 objset_t *mos = dp->dp_meta_objset;
1084 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
1088 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
1089 ASSERT(dmu_tx_is_syncing(tx));
1092 * If the pool was created prior to SPA_VERSION_USERREFS, the
1093 * zap object for temporary holds might not exist yet.
1097 dsl_pool_user_hold_create_obj(dp, tx);
1098 zapobj = dp->dp_tmp_userrefs_obj;
1104 name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag);
1106 error = zap_add(mos, zapobj, name, 8, 1, now, tx);
1108 error = zap_remove(mos, zapobj, name, tx);
1115 * Add a temporary hold for the given dataset object and tag.
1118 dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1119 uint64_t *now, dmu_tx_t *tx)
1121 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE));
1125 * Release a temporary hold for the given dataset object and tag.
1128 dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1131 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, NULL,
1135 #if defined(_KERNEL) && defined(HAVE_SPL)
1136 module_param(zfs_no_write_throttle, int, 0644);
1137 MODULE_PARM_DESC(zfs_no_write_throttle, "Disable write throttling");
1139 module_param(zfs_write_limit_shift, int, 0444);
1140 MODULE_PARM_DESC(zfs_write_limit_shift, "log2(fraction of memory) per txg");
1142 module_param(zfs_txg_synctime_ms, int, 0644);
1143 MODULE_PARM_DESC(zfs_txg_synctime_ms, "Target milliseconds between txg sync");
1145 module_param(zfs_txg_history, int, 0644);
1146 MODULE_PARM_DESC(zfs_txg_history, "Historic statistics for the last N txgs");
1148 module_param(zfs_write_limit_min, ulong, 0444);
1149 MODULE_PARM_DESC(zfs_write_limit_min, "Min txg write limit");
1151 module_param(zfs_write_limit_max, ulong, 0444);
1152 MODULE_PARM_DESC(zfs_write_limit_max, "Max txg write limit");
1154 module_param(zfs_write_limit_inflated, ulong, 0444);
1155 MODULE_PARM_DESC(zfs_write_limit_inflated, "Inflated txg write limit");
1157 module_param(zfs_write_limit_override, ulong, 0444);
1158 MODULE_PARM_DESC(zfs_write_limit_override, "Override txg write limit");