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_txg_history_update(kstat_t *ksp, int rw)
64 dsl_pool_t *dp = ksp->ks_private;
68 if (rw == KSTAT_WRITE)
72 kmem_free(ksp->ks_data, ksp->ks_data_size);
74 mutex_enter(&dp->dp_lock);
76 ksp->ks_ndata = dp->dp_txg_history_size;
77 ksp->ks_data_size = dp->dp_txg_history_size * sizeof(kstat_txg_t);
78 if (ksp->ks_data_size > 0)
79 ksp->ks_data = kmem_alloc(ksp->ks_data_size, KM_PUSHPAGE);
81 /* Traversed oldest to youngest for the most readable kstat output */
82 for (th = list_tail(&dp->dp_txg_history); th != NULL;
83 th = list_prev(&dp->dp_txg_history, th)) {
84 mutex_enter(&th->th_lock);
85 ASSERT3S(i + sizeof(kstat_txg_t), <=, ksp->ks_data_size);
86 memcpy(ksp->ks_data + i, &th->th_kstat, sizeof(kstat_txg_t));
87 i += sizeof(kstat_txg_t);
88 mutex_exit(&th->th_lock);
91 mutex_exit(&dp->dp_lock);
97 dsl_pool_txg_history_init(dsl_pool_t *dp, uint64_t txg)
99 char name[KSTAT_STRLEN];
101 list_create(&dp->dp_txg_history, sizeof (txg_history_t),
102 offsetof(txg_history_t, th_link));
103 dsl_pool_txg_history_add(dp, txg);
105 (void) snprintf(name, KSTAT_STRLEN, "txgs-%s", spa_name(dp->dp_spa));
106 dp->dp_txg_kstat = kstat_create("zfs", 0, name, "misc",
107 KSTAT_TYPE_TXG, 0, KSTAT_FLAG_VIRTUAL);
108 if (dp->dp_txg_kstat) {
109 dp->dp_txg_kstat->ks_data = NULL;
110 dp->dp_txg_kstat->ks_private = dp;
111 dp->dp_txg_kstat->ks_update = dsl_pool_txg_history_update;
112 kstat_install(dp->dp_txg_kstat);
117 dsl_pool_txg_history_destroy(dsl_pool_t *dp)
121 if (dp->dp_txg_kstat) {
122 if (dp->dp_txg_kstat->ks_data)
123 kmem_free(dp->dp_txg_kstat->ks_data,
124 dp->dp_txg_kstat->ks_data_size);
126 kstat_delete(dp->dp_txg_kstat);
129 mutex_enter(&dp->dp_lock);
130 while ((th = list_remove_head(&dp->dp_txg_history))) {
131 dp->dp_txg_history_size--;
132 mutex_destroy(&th->th_lock);
133 kmem_free(th, sizeof(txg_history_t));
136 ASSERT3U(dp->dp_txg_history_size, ==, 0);
137 list_destroy(&dp->dp_txg_history);
138 mutex_exit(&dp->dp_lock);
142 dsl_pool_txg_history_add(dsl_pool_t *dp, uint64_t txg)
144 txg_history_t *th, *rm;
146 th = kmem_zalloc(sizeof(txg_history_t), KM_SLEEP);
147 mutex_init(&th->th_lock, NULL, MUTEX_DEFAULT, NULL);
148 th->th_kstat.txg = txg;
149 th->th_kstat.state = TXG_STATE_OPEN;
150 th->th_kstat.birth = gethrtime();
152 mutex_enter(&dp->dp_lock);
154 list_insert_head(&dp->dp_txg_history, th);
155 dp->dp_txg_history_size++;
157 while (dp->dp_txg_history_size > zfs_txg_history) {
158 dp->dp_txg_history_size--;
159 rm = list_remove_tail(&dp->dp_txg_history);
160 mutex_destroy(&rm->th_lock);
161 kmem_free(rm, sizeof(txg_history_t));
164 mutex_exit(&dp->dp_lock);
170 * Traversed youngest to oldest because lookups are only done for open
171 * or syncing txgs which are guaranteed to be at the head of the list.
172 * The txg_history_t structure will be returned locked.
175 dsl_pool_txg_history_get(dsl_pool_t *dp, uint64_t txg)
179 mutex_enter(&dp->dp_lock);
180 for (th = list_head(&dp->dp_txg_history); th != NULL;
181 th = list_next(&dp->dp_txg_history, th)) {
182 if (th->th_kstat.txg == txg) {
183 mutex_enter(&th->th_lock);
187 mutex_exit(&dp->dp_lock);
193 dsl_pool_txg_history_put(txg_history_t *th)
195 mutex_exit(&th->th_lock);
199 dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
204 err = zap_lookup(dp->dp_meta_objset,
205 dp->dp_root_dir->dd_phys->dd_child_dir_zapobj,
206 name, sizeof (obj), 1, &obj);
210 return (dsl_dir_open_obj(dp, obj, name, dp, ddp));
214 dsl_pool_open_impl(spa_t *spa, uint64_t txg)
217 blkptr_t *bp = spa_get_rootblkptr(spa);
219 dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
221 dp->dp_meta_rootbp = *bp;
222 rw_init(&dp->dp_config_rwlock, NULL, RW_DEFAULT, NULL);
223 dp->dp_write_limit = zfs_write_limit_min;
226 txg_list_create(&dp->dp_dirty_datasets,
227 offsetof(dsl_dataset_t, ds_dirty_link));
228 txg_list_create(&dp->dp_dirty_zilogs,
229 offsetof(zilog_t, zl_dirty_link));
230 txg_list_create(&dp->dp_dirty_dirs,
231 offsetof(dsl_dir_t, dd_dirty_link));
232 txg_list_create(&dp->dp_sync_tasks,
233 offsetof(dsl_sync_task_group_t, dstg_node));
235 mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
237 dp->dp_iput_taskq = taskq_create("zfs_iput_taskq", 1, minclsyspri,
240 dsl_pool_txg_history_init(dp, txg);
246 dsl_pool_init(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
249 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
251 err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,
252 &dp->dp_meta_objset);
262 dsl_pool_open(dsl_pool_t *dp)
269 rw_enter(&dp->dp_config_rwlock, RW_WRITER);
270 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
271 DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
272 &dp->dp_root_dir_obj);
276 err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
277 NULL, dp, &dp->dp_root_dir);
281 err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir);
285 if (spa_version(dp->dp_spa) >= SPA_VERSION_ORIGIN) {
286 err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd);
289 err = dsl_dataset_hold_obj(dp, dd->dd_phys->dd_head_dataset_obj,
292 err = dsl_dataset_hold_obj(dp,
293 ds->ds_phys->ds_prev_snap_obj, dp,
294 &dp->dp_origin_snap);
295 dsl_dataset_rele(ds, FTAG);
297 dsl_dir_close(dd, dp);
302 if (spa_version(dp->dp_spa) >= SPA_VERSION_DEADLISTS) {
303 err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME,
308 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
309 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj);
312 VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
313 dp->dp_meta_objset, obj));
316 if (spa_feature_is_active(dp->dp_spa,
317 &spa_feature_table[SPA_FEATURE_ASYNC_DESTROY])) {
318 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
319 DMU_POOL_BPTREE_OBJ, sizeof (uint64_t), 1,
325 err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
326 DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
327 &dp->dp_tmp_userrefs_obj);
333 err = dsl_scan_init(dp, dp->dp_tx.tx_open_txg);
336 rw_exit(&dp->dp_config_rwlock);
341 dsl_pool_close(dsl_pool_t *dp)
343 /* drop our references from dsl_pool_open() */
346 * Since we held the origin_snap from "syncing" context (which
347 * includes pool-opening context), it actually only got a "ref"
348 * and not a hold, so just drop that here.
350 if (dp->dp_origin_snap)
351 dsl_dataset_drop_ref(dp->dp_origin_snap, dp);
353 dsl_dir_close(dp->dp_mos_dir, dp);
355 dsl_dir_close(dp->dp_free_dir, dp);
357 dsl_dir_close(dp->dp_root_dir, dp);
359 bpobj_close(&dp->dp_free_bpobj);
361 /* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
362 if (dp->dp_meta_objset)
363 dmu_objset_evict(dp->dp_meta_objset);
365 txg_list_destroy(&dp->dp_dirty_datasets);
366 txg_list_destroy(&dp->dp_dirty_zilogs);
367 txg_list_destroy(&dp->dp_sync_tasks);
368 txg_list_destroy(&dp->dp_dirty_dirs);
370 arc_flush(dp->dp_spa);
373 dsl_pool_txg_history_destroy(dp);
374 rw_destroy(&dp->dp_config_rwlock);
375 mutex_destroy(&dp->dp_lock);
376 taskq_destroy(dp->dp_iput_taskq);
378 kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
379 kmem_free(dp, sizeof (dsl_pool_t));
383 dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)
386 dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
387 dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
392 /* create and open the MOS (meta-objset) */
393 dp->dp_meta_objset = dmu_objset_create_impl(spa,
394 NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);
396 /* create the pool directory */
397 err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
398 DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
399 ASSERT3U(err, ==, 0);
401 /* Initialize scan structures */
402 VERIFY3U(0, ==, dsl_scan_init(dp, txg));
404 /* create and open the root dir */
405 dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);
406 VERIFY(0 == dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
407 NULL, dp, &dp->dp_root_dir));
409 /* create and open the meta-objset dir */
410 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);
411 VERIFY(0 == dsl_pool_open_special_dir(dp,
412 MOS_DIR_NAME, &dp->dp_mos_dir));
414 if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
415 /* create and open the free dir */
416 (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
418 VERIFY(0 == dsl_pool_open_special_dir(dp,
419 FREE_DIR_NAME, &dp->dp_free_dir));
421 /* create and open the free_bplist */
422 obj = bpobj_alloc(dp->dp_meta_objset, SPA_MAXBLOCKSIZE, tx);
423 VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
424 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0);
425 VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
426 dp->dp_meta_objset, obj));
429 if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB)
430 dsl_pool_create_origin(dp, tx);
432 /* create the root dataset */
433 obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);
435 /* create the root objset */
436 VERIFY(0 == dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
437 VERIFY(NULL != (os = dmu_objset_create_impl(dp->dp_spa, ds,
438 dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx)));
440 zfs_create_fs(os, kcred, zplprops, tx);
442 dsl_dataset_rele(ds, FTAG);
450 * Account for the meta-objset space in its placeholder dsl_dir.
453 dsl_pool_mos_diduse_space(dsl_pool_t *dp,
454 int64_t used, int64_t comp, int64_t uncomp)
456 ASSERT3U(comp, ==, uncomp); /* it's all metadata */
457 mutex_enter(&dp->dp_lock);
458 dp->dp_mos_used_delta += used;
459 dp->dp_mos_compressed_delta += comp;
460 dp->dp_mos_uncompressed_delta += uncomp;
461 mutex_exit(&dp->dp_lock);
465 deadlist_enqueue_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
467 dsl_deadlist_t *dl = arg;
468 dsl_pool_t *dp = dmu_objset_pool(dl->dl_os);
469 rw_enter(&dp->dp_config_rwlock, RW_READER);
470 dsl_deadlist_insert(dl, bp, tx);
471 rw_exit(&dp->dp_config_rwlock);
476 dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
482 objset_t *mos = dp->dp_meta_objset;
483 hrtime_t start, write_time;
484 uint64_t data_written;
486 list_t synced_datasets;
488 list_create(&synced_datasets, sizeof (dsl_dataset_t),
489 offsetof(dsl_dataset_t, ds_synced_link));
492 * We need to copy dp_space_towrite() before doing
493 * dsl_sync_task_group_sync(), because
494 * dsl_dataset_snapshot_reserve_space() will increase
495 * dp_space_towrite but not actually write anything.
497 data_written = dp->dp_space_towrite[txg & TXG_MASK];
499 tx = dmu_tx_create_assigned(dp, txg);
501 dp->dp_read_overhead = 0;
504 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
505 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg))) {
507 * We must not sync any non-MOS datasets twice, because
508 * we may have taken a snapshot of them. However, we
509 * may sync newly-created datasets on pass 2.
511 ASSERT(!list_link_active(&ds->ds_synced_link));
512 list_insert_tail(&synced_datasets, ds);
513 dsl_dataset_sync(ds, zio, tx);
515 DTRACE_PROBE(pool_sync__1setup);
518 write_time = gethrtime() - start;
520 DTRACE_PROBE(pool_sync__2rootzio);
523 * After the data blocks have been written (ensured by the zio_wait()
524 * above), update the user/group space accounting.
526 for (ds = list_head(&synced_datasets); ds;
527 ds = list_next(&synced_datasets, ds))
528 dmu_objset_do_userquota_updates(ds->ds_objset, tx);
531 * Sync the datasets again to push out the changes due to
532 * userspace updates. This must be done before we process the
533 * sync tasks, so that any snapshots will have the correct
534 * user accounting information (and we won't get confused
535 * about which blocks are part of the snapshot).
537 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
538 while ((ds = txg_list_remove(&dp->dp_dirty_datasets, txg))) {
539 ASSERT(list_link_active(&ds->ds_synced_link));
540 dmu_buf_rele(ds->ds_dbuf, ds);
541 dsl_dataset_sync(ds, zio, tx);
546 * Now that the datasets have been completely synced, we can
547 * clean up our in-memory structures accumulated while syncing:
549 * - move dead blocks from the pending deadlist to the on-disk deadlist
550 * - clean up zil records
551 * - release hold from dsl_dataset_dirty()
553 while ((ds = list_remove_head(&synced_datasets))) {
554 ASSERTV(objset_t *os = ds->ds_objset);
555 bplist_iterate(&ds->ds_pending_deadlist,
556 deadlist_enqueue_cb, &ds->ds_deadlist, tx);
557 ASSERT(!dmu_objset_is_dirty(os, txg));
558 dmu_buf_rele(ds->ds_dbuf, ds);
562 while ((dd = txg_list_remove(&dp->dp_dirty_dirs, txg)))
563 dsl_dir_sync(dd, tx);
564 write_time += gethrtime() - start;
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;
583 if (list_head(&mos->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||
584 list_head(&mos->os_free_dnodes[txg & TXG_MASK]) != NULL) {
585 zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
586 dmu_objset_sync(mos, zio, tx);
589 dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
590 spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
592 write_time += gethrtime() - start;
593 DTRACE_PROBE2(pool_sync__4io, hrtime_t, write_time,
594 hrtime_t, dp->dp_read_overhead);
595 write_time -= dp->dp_read_overhead;
598 * If we modify a dataset in the same txg that we want to destroy it,
599 * its dsl_dir's dd_dbuf will be dirty, and thus have a hold on it.
600 * dsl_dir_destroy_check() will fail if there are unexpected holds.
601 * Therefore, we want to sync the MOS (thus syncing the dd_dbuf
602 * and clearing the hold on it) before we process the sync_tasks.
603 * The MOS data dirtied by the sync_tasks will be synced on the next
606 DTRACE_PROBE(pool_sync__3task);
607 if (!txg_list_empty(&dp->dp_sync_tasks, txg)) {
608 dsl_sync_task_group_t *dstg;
610 * No more sync tasks should have been added while we
613 ASSERT(spa_sync_pass(dp->dp_spa) == 1);
614 while ((dstg = txg_list_remove(&dp->dp_sync_tasks, txg)))
615 dsl_sync_task_group_sync(dstg, tx);
620 dp->dp_space_towrite[txg & TXG_MASK] = 0;
621 ASSERT(dp->dp_tempreserved[txg & TXG_MASK] == 0);
624 * If the write limit max has not been explicitly set, set it
625 * to a fraction of available physical memory (default 1/8th).
626 * Note that we must inflate the limit because the spa
627 * inflates write sizes to account for data replication.
628 * Check this each sync phase to catch changing memory size.
630 if (physmem != old_physmem && zfs_write_limit_shift) {
631 mutex_enter(&zfs_write_limit_lock);
632 old_physmem = physmem;
633 zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift;
634 zfs_write_limit_inflated = MAX(zfs_write_limit_min,
635 spa_get_asize(dp->dp_spa, zfs_write_limit_max));
636 mutex_exit(&zfs_write_limit_lock);
640 * Attempt to keep the sync time consistent by adjusting the
641 * amount of write traffic allowed into each transaction group.
642 * Weight the throughput calculation towards the current value:
643 * thru = 3/4 old_thru + 1/4 new_thru
645 * Note: write_time is in nanosecs, so write_time/MICROSEC
648 ASSERT(zfs_write_limit_min > 0);
649 if (data_written > zfs_write_limit_min / 8 && write_time > MICROSEC) {
650 uint64_t throughput = data_written / (write_time / MICROSEC);
652 if (dp->dp_throughput)
653 dp->dp_throughput = throughput / 4 +
654 3 * dp->dp_throughput / 4;
656 dp->dp_throughput = throughput;
657 dp->dp_write_limit = MIN(zfs_write_limit_inflated,
658 MAX(zfs_write_limit_min,
659 dp->dp_throughput * zfs_txg_synctime_ms));
664 dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)
669 while ((zilog = txg_list_remove(&dp->dp_dirty_zilogs, txg))) {
670 ds = dmu_objset_ds(zilog->zl_os);
671 zil_clean(zilog, txg);
672 ASSERT(!dmu_objset_is_dirty(zilog->zl_os, txg));
673 dmu_buf_rele(ds->ds_dbuf, zilog);
675 ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));
679 * TRUE if the current thread is the tx_sync_thread or if we
680 * are being called from SPA context during pool initialization.
683 dsl_pool_sync_context(dsl_pool_t *dp)
685 return (curthread == dp->dp_tx.tx_sync_thread ||
686 spa_is_initializing(dp->dp_spa));
690 dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree)
692 uint64_t space, resv;
695 * Reserve about 1.6% (1/64), or at least 32MB, for allocation
697 * XXX The intent log is not accounted for, so it must fit
700 * If we're trying to assess whether it's OK to do a free,
701 * cut the reservation in half to allow forward progress
702 * (e.g. make it possible to rm(1) files from a full pool).
704 space = spa_get_dspace(dp->dp_spa);
705 resv = MAX(space >> 6, SPA_MINDEVSIZE >> 1);
709 return (space - resv);
713 dsl_pool_tempreserve_space(dsl_pool_t *dp, uint64_t space, dmu_tx_t *tx)
715 uint64_t reserved = 0;
716 uint64_t write_limit = (zfs_write_limit_override ?
717 zfs_write_limit_override : dp->dp_write_limit);
719 if (zfs_no_write_throttle) {
720 atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK],
726 * Check to see if we have exceeded the maximum allowed IO for
727 * this transaction group. We can do this without locks since
728 * a little slop here is ok. Note that we do the reserved check
729 * with only half the requested reserve: this is because the
730 * reserve requests are worst-case, and we really don't want to
731 * throttle based off of worst-case estimates.
733 if (write_limit > 0) {
734 reserved = dp->dp_space_towrite[tx->tx_txg & TXG_MASK]
735 + dp->dp_tempreserved[tx->tx_txg & TXG_MASK] / 2;
737 if (reserved && reserved > write_limit) {
738 DMU_TX_STAT_BUMP(dmu_tx_write_limit);
743 atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], space);
746 * If this transaction group is over 7/8ths capacity, delay
747 * the caller 1 clock tick. This will slow down the "fill"
748 * rate until the sync process can catch up with us.
750 if (reserved && reserved > (write_limit - (write_limit >> 3)))
751 txg_delay(dp, tx->tx_txg, 1);
757 dsl_pool_tempreserve_clear(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
759 ASSERT(dp->dp_tempreserved[tx->tx_txg & TXG_MASK] >= space);
760 atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], -space);
764 dsl_pool_memory_pressure(dsl_pool_t *dp)
766 uint64_t space_inuse = 0;
769 if (dp->dp_write_limit == zfs_write_limit_min)
772 for (i = 0; i < TXG_SIZE; i++) {
773 space_inuse += dp->dp_space_towrite[i];
774 space_inuse += dp->dp_tempreserved[i];
776 dp->dp_write_limit = MAX(zfs_write_limit_min,
777 MIN(dp->dp_write_limit, space_inuse / 4));
781 dsl_pool_willuse_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
784 mutex_enter(&dp->dp_lock);
785 dp->dp_space_towrite[tx->tx_txg & TXG_MASK] += space;
786 mutex_exit(&dp->dp_lock);
792 upgrade_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
795 dsl_dataset_t *ds, *prev = NULL;
797 dsl_pool_t *dp = spa_get_dsl(spa);
799 err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
803 while (ds->ds_phys->ds_prev_snap_obj != 0) {
804 err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
807 dsl_dataset_rele(ds, FTAG);
811 if (prev->ds_phys->ds_next_snap_obj != ds->ds_object)
813 dsl_dataset_rele(ds, FTAG);
819 prev = dp->dp_origin_snap;
822 * The $ORIGIN can't have any data, or the accounting
825 ASSERT(prev->ds_phys->ds_bp.blk_birth == 0);
827 /* The origin doesn't get attached to itself */
828 if (ds->ds_object == prev->ds_object) {
829 dsl_dataset_rele(ds, FTAG);
833 dmu_buf_will_dirty(ds->ds_dbuf, tx);
834 ds->ds_phys->ds_prev_snap_obj = prev->ds_object;
835 ds->ds_phys->ds_prev_snap_txg = prev->ds_phys->ds_creation_txg;
837 dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
838 ds->ds_dir->dd_phys->dd_origin_obj = prev->ds_object;
840 dmu_buf_will_dirty(prev->ds_dbuf, tx);
841 prev->ds_phys->ds_num_children++;
843 if (ds->ds_phys->ds_next_snap_obj == 0) {
844 ASSERT(ds->ds_prev == NULL);
845 VERIFY(0 == dsl_dataset_hold_obj(dp,
846 ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev));
850 ASSERT(ds->ds_dir->dd_phys->dd_origin_obj == prev->ds_object);
851 ASSERT(ds->ds_phys->ds_prev_snap_obj == prev->ds_object);
853 if (prev->ds_phys->ds_next_clones_obj == 0) {
854 dmu_buf_will_dirty(prev->ds_dbuf, tx);
855 prev->ds_phys->ds_next_clones_obj =
856 zap_create(dp->dp_meta_objset,
857 DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
859 VERIFY(0 == zap_add_int(dp->dp_meta_objset,
860 prev->ds_phys->ds_next_clones_obj, ds->ds_object, tx));
862 dsl_dataset_rele(ds, FTAG);
863 if (prev != dp->dp_origin_snap)
864 dsl_dataset_rele(prev, FTAG);
869 dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx)
871 ASSERT(dmu_tx_is_syncing(tx));
872 ASSERT(dp->dp_origin_snap != NULL);
874 VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL, upgrade_clones_cb,
875 tx, DS_FIND_CHILDREN));
880 upgrade_dir_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
884 dsl_pool_t *dp = spa_get_dsl(spa);
885 objset_t *mos = dp->dp_meta_objset;
887 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
889 if (ds->ds_dir->dd_phys->dd_origin_obj) {
890 dsl_dataset_t *origin;
892 VERIFY3U(0, ==, dsl_dataset_hold_obj(dp,
893 ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin));
895 if (origin->ds_dir->dd_phys->dd_clones == 0) {
896 dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
897 origin->ds_dir->dd_phys->dd_clones = zap_create(mos,
898 DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
901 VERIFY3U(0, ==, zap_add_int(dp->dp_meta_objset,
902 origin->ds_dir->dd_phys->dd_clones, dsobj, tx));
904 dsl_dataset_rele(origin, FTAG);
907 dsl_dataset_rele(ds, FTAG);
912 dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx)
916 ASSERT(dmu_tx_is_syncing(tx));
918 (void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx);
919 VERIFY(0 == dsl_pool_open_special_dir(dp,
920 FREE_DIR_NAME, &dp->dp_free_dir));
923 * We can't use bpobj_alloc(), because spa_version() still
924 * returns the old version, and we need a new-version bpobj with
925 * subobj support. So call dmu_object_alloc() directly.
927 obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ,
928 SPA_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx);
929 VERIFY3U(0, ==, zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
930 DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
931 VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
932 dp->dp_meta_objset, obj));
934 VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL,
935 upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN));
939 dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
944 ASSERT(dmu_tx_is_syncing(tx));
945 ASSERT(dp->dp_origin_snap == NULL);
947 /* create the origin dir, ds, & snap-ds */
948 rw_enter(&dp->dp_config_rwlock, RW_WRITER);
949 dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME,
951 VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
952 dsl_dataset_snapshot_sync(ds, ORIGIN_DIR_NAME, tx);
953 VERIFY(0 == dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
954 dp, &dp->dp_origin_snap));
955 dsl_dataset_rele(ds, FTAG);
956 rw_exit(&dp->dp_config_rwlock);
960 dsl_pool_iput_taskq(dsl_pool_t *dp)
962 return (dp->dp_iput_taskq);
966 * Walk through the pool-wide zap object of temporary snapshot user holds
970 dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp)
974 objset_t *mos = dp->dp_meta_objset;
975 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
979 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
981 for (zap_cursor_init(&zc, mos, zapobj);
982 zap_cursor_retrieve(&zc, &za) == 0;
983 zap_cursor_advance(&zc)) {
987 htag = strchr(za.za_name, '-');
990 dsobj = strtonum(za.za_name, NULL);
991 (void) dsl_dataset_user_release_tmp(dp, dsobj, htag, B_FALSE);
993 zap_cursor_fini(&zc);
997 * Create the pool-wide zap object for storing temporary snapshot holds.
1000 dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx)
1002 objset_t *mos = dp->dp_meta_objset;
1004 ASSERT(dp->dp_tmp_userrefs_obj == 0);
1005 ASSERT(dmu_tx_is_syncing(tx));
1007 dp->dp_tmp_userrefs_obj = zap_create_link(mos, DMU_OT_USERREFS,
1008 DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS, tx);
1012 dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj,
1013 const char *tag, uint64_t *now, dmu_tx_t *tx, boolean_t holding)
1015 objset_t *mos = dp->dp_meta_objset;
1016 uint64_t zapobj = dp->dp_tmp_userrefs_obj;
1020 ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
1021 ASSERT(dmu_tx_is_syncing(tx));
1024 * If the pool was created prior to SPA_VERSION_USERREFS, the
1025 * zap object for temporary holds might not exist yet.
1029 dsl_pool_user_hold_create_obj(dp, tx);
1030 zapobj = dp->dp_tmp_userrefs_obj;
1036 name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag);
1038 error = zap_add(mos, zapobj, name, 8, 1, now, tx);
1040 error = zap_remove(mos, zapobj, name, tx);
1047 * Add a temporary hold for the given dataset object and tag.
1050 dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1051 uint64_t *now, dmu_tx_t *tx)
1053 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE));
1057 * Release a temporary hold for the given dataset object and tag.
1060 dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
1063 return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, NULL,
1067 #if defined(_KERNEL) && defined(HAVE_SPL)
1068 module_param(zfs_no_write_throttle, int, 0644);
1069 MODULE_PARM_DESC(zfs_no_write_throttle, "Disable write throttling");
1071 module_param(zfs_write_limit_shift, int, 0444);
1072 MODULE_PARM_DESC(zfs_write_limit_shift, "log2(fraction of memory) per txg");
1074 module_param(zfs_txg_synctime_ms, int, 0644);
1075 MODULE_PARM_DESC(zfs_txg_synctime_ms, "Target milliseconds between txg sync");
1077 module_param(zfs_txg_history, int, 0644);
1078 MODULE_PARM_DESC(zfs_txg_history, "Historic statistics for the last N txgs");
1080 module_param(zfs_write_limit_min, ulong, 0444);
1081 MODULE_PARM_DESC(zfs_write_limit_min, "Min txg write limit");
1083 module_param(zfs_write_limit_max, ulong, 0444);
1084 MODULE_PARM_DESC(zfs_write_limit_max, "Max txg write limit");
1086 module_param(zfs_write_limit_inflated, ulong, 0444);
1087 MODULE_PARM_DESC(zfs_write_limit_inflated, "Inflated txg write limit");
1089 module_param(zfs_write_limit_override, ulong, 0444);
1090 MODULE_PARM_DESC(zfs_write_limit_override, "Override txg write limit");