xref: /onnv-gate/usr/src/uts/common/fs/zfs/dsl_pool.c (revision 10956:0c81acaaf614)
1789Sahrens /*
2789Sahrens  * CDDL HEADER START
3789Sahrens  *
4789Sahrens  * The contents of this file are subject to the terms of the
51544Seschrock  * Common Development and Distribution License (the "License").
61544Seschrock  * You may not use this file except in compliance with the License.
7789Sahrens  *
8789Sahrens  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9789Sahrens  * or http://www.opensolaris.org/os/licensing.
10789Sahrens  * See the License for the specific language governing permissions
11789Sahrens  * and limitations under the License.
12789Sahrens  *
13789Sahrens  * When distributing Covered Code, include this CDDL HEADER in each
14789Sahrens  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15789Sahrens  * If applicable, add the following below this CDDL HEADER, with the
16789Sahrens  * fields enclosed by brackets "[]" replaced with your own identifying
17789Sahrens  * information: Portions Copyright [yyyy] [name of copyright owner]
18789Sahrens  *
19789Sahrens  * CDDL HEADER END
20789Sahrens  */
21789Sahrens /*
229008SLin.Ling@Sun.COM  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23789Sahrens  * Use is subject to license terms.
24789Sahrens  */
25789Sahrens 
26789Sahrens #include <sys/dsl_pool.h>
27789Sahrens #include <sys/dsl_dataset.h>
28789Sahrens #include <sys/dsl_dir.h>
292199Sahrens #include <sys/dsl_synctask.h>
30789Sahrens #include <sys/dmu_tx.h>
31789Sahrens #include <sys/dmu_objset.h>
32789Sahrens #include <sys/arc.h>
33789Sahrens #include <sys/zap.h>
343547Smaybee #include <sys/zio.h>
35789Sahrens #include <sys/zfs_context.h>
36789Sahrens #include <sys/fs/zfs.h>
377046Sahrens #include <sys/zfs_znode.h>
387046Sahrens #include <sys/spa_impl.h>
39789Sahrens 
406245Smaybee int zfs_no_write_throttle = 0;
417468SMark.Maybee@Sun.COM int zfs_write_limit_shift = 3;			/* 1/8th of physical memory */
427468SMark.Maybee@Sun.COM int zfs_txg_synctime = 5;			/* target secs to sync a txg */
437468SMark.Maybee@Sun.COM 
447468SMark.Maybee@Sun.COM uint64_t zfs_write_limit_min = 32 << 20;	/* min write limit is 32MB */
457468SMark.Maybee@Sun.COM uint64_t zfs_write_limit_max = 0;		/* max data payload per txg */
467468SMark.Maybee@Sun.COM uint64_t zfs_write_limit_inflated = 0;
476245Smaybee uint64_t zfs_write_limit_override = 0;
486245Smaybee 
497468SMark.Maybee@Sun.COM kmutex_t zfs_write_limit_lock;
507468SMark.Maybee@Sun.COM 
517468SMark.Maybee@Sun.COM static pgcnt_t old_physmem = 0;
527046Sahrens 
531544Seschrock static int
547046Sahrens dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
55789Sahrens {
56789Sahrens 	uint64_t obj;
57789Sahrens 	int err;
58789Sahrens 
59789Sahrens 	err = zap_lookup(dp->dp_meta_objset,
60789Sahrens 	    dp->dp_root_dir->dd_phys->dd_child_dir_zapobj,
617046Sahrens 	    name, sizeof (obj), 1, &obj);
621544Seschrock 	if (err)
631544Seschrock 		return (err);
64789Sahrens 
657046Sahrens 	return (dsl_dir_open_obj(dp, obj, name, dp, ddp));
66789Sahrens }
67789Sahrens 
68789Sahrens static dsl_pool_t *
69789Sahrens dsl_pool_open_impl(spa_t *spa, uint64_t txg)
70789Sahrens {
71789Sahrens 	dsl_pool_t *dp;
72789Sahrens 	blkptr_t *bp = spa_get_rootblkptr(spa);
73789Sahrens 
74789Sahrens 	dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
75789Sahrens 	dp->dp_spa = spa;
76789Sahrens 	dp->dp_meta_rootbp = *bp;
772856Snd150628 	rw_init(&dp->dp_config_rwlock, NULL, RW_DEFAULT, NULL);
786245Smaybee 	dp->dp_write_limit = zfs_write_limit_min;
79789Sahrens 	txg_init(dp, txg);
80789Sahrens 
81789Sahrens 	txg_list_create(&dp->dp_dirty_datasets,
82789Sahrens 	    offsetof(dsl_dataset_t, ds_dirty_link));
83789Sahrens 	txg_list_create(&dp->dp_dirty_dirs,
84789Sahrens 	    offsetof(dsl_dir_t, dd_dirty_link));
852199Sahrens 	txg_list_create(&dp->dp_sync_tasks,
862199Sahrens 	    offsetof(dsl_sync_task_group_t, dstg_node));
875367Sahrens 	list_create(&dp->dp_synced_datasets, sizeof (dsl_dataset_t),
88789Sahrens 	    offsetof(dsl_dataset_t, ds_synced_link));
89789Sahrens 
906245Smaybee 	mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
917046Sahrens 	mutex_init(&dp->dp_scrub_cancel_lock, NULL, MUTEX_DEFAULT, NULL);
926245Smaybee 
939321SNeil.Perrin@Sun.COM 	dp->dp_vnrele_taskq = taskq_create("zfs_vn_rele_taskq", 1, minclsyspri,
949321SNeil.Perrin@Sun.COM 	    1, 4, 0);
959321SNeil.Perrin@Sun.COM 
96789Sahrens 	return (dp);
97789Sahrens }
98789Sahrens 
991544Seschrock int
1001544Seschrock dsl_pool_open(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
101789Sahrens {
102789Sahrens 	int err;
103789Sahrens 	dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
1047046Sahrens 	dsl_dir_t *dd;
1057046Sahrens 	dsl_dataset_t *ds;
106789Sahrens 
1077046Sahrens 	rw_enter(&dp->dp_config_rwlock, RW_WRITER);
10810298SMatthew.Ahrens@Sun.COM 	err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,
10910298SMatthew.Ahrens@Sun.COM 	    &dp->dp_meta_objset);
1101544Seschrock 	if (err)
1111544Seschrock 		goto out;
1121544Seschrock 
113789Sahrens 	err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
114789Sahrens 	    DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
115789Sahrens 	    &dp->dp_root_dir_obj);
1161544Seschrock 	if (err)
1171544Seschrock 		goto out;
1181544Seschrock 
1191544Seschrock 	err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
1201544Seschrock 	    NULL, dp, &dp->dp_root_dir);
1211544Seschrock 	if (err)
1221544Seschrock 		goto out;
123789Sahrens 
1247046Sahrens 	err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir);
1251544Seschrock 	if (err)
1261544Seschrock 		goto out;
1271544Seschrock 
1287046Sahrens 	if (spa_version(spa) >= SPA_VERSION_ORIGIN) {
1297046Sahrens 		err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd);
1307046Sahrens 		if (err)
1317046Sahrens 			goto out;
1327046Sahrens 		err = dsl_dataset_hold_obj(dp, dd->dd_phys->dd_head_dataset_obj,
1337046Sahrens 		    FTAG, &ds);
1349008SLin.Ling@Sun.COM 		if (err == 0) {
1359008SLin.Ling@Sun.COM 			err = dsl_dataset_hold_obj(dp,
1369008SLin.Ling@Sun.COM 			    ds->ds_phys->ds_prev_snap_obj, dp,
1379008SLin.Ling@Sun.COM 			    &dp->dp_origin_snap);
1389008SLin.Ling@Sun.COM 			dsl_dataset_rele(ds, FTAG);
1399008SLin.Ling@Sun.COM 		}
1409008SLin.Ling@Sun.COM 		dsl_dir_close(dd, dp);
1417046Sahrens 		if (err)
1427046Sahrens 			goto out;
1437046Sahrens 	}
1447046Sahrens 
14510342Schris.kirby@sun.com 	err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
14610342Schris.kirby@sun.com 	    DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
14710342Schris.kirby@sun.com 	    &dp->dp_tmp_userrefs_obj);
14810342Schris.kirby@sun.com 	if (err == ENOENT)
14910342Schris.kirby@sun.com 		err = 0;
15010342Schris.kirby@sun.com 	if (err)
15110342Schris.kirby@sun.com 		goto out;
15210342Schris.kirby@sun.com 
1537046Sahrens 	/* get scrub status */
1547046Sahrens 	err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1557046Sahrens 	    DMU_POOL_SCRUB_FUNC, sizeof (uint32_t), 1,
1567046Sahrens 	    &dp->dp_scrub_func);
1577046Sahrens 	if (err == 0) {
1587046Sahrens 		err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1597046Sahrens 		    DMU_POOL_SCRUB_QUEUE, sizeof (uint64_t), 1,
1607046Sahrens 		    &dp->dp_scrub_queue_obj);
1617046Sahrens 		if (err)
1627046Sahrens 			goto out;
1637046Sahrens 		err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1647046Sahrens 		    DMU_POOL_SCRUB_MIN_TXG, sizeof (uint64_t), 1,
1657046Sahrens 		    &dp->dp_scrub_min_txg);
1667046Sahrens 		if (err)
1677046Sahrens 			goto out;
1687046Sahrens 		err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1697046Sahrens 		    DMU_POOL_SCRUB_MAX_TXG, sizeof (uint64_t), 1,
1707046Sahrens 		    &dp->dp_scrub_max_txg);
1717046Sahrens 		if (err)
1727046Sahrens 			goto out;
1737046Sahrens 		err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1747046Sahrens 		    DMU_POOL_SCRUB_BOOKMARK, sizeof (uint64_t), 4,
1757046Sahrens 		    &dp->dp_scrub_bookmark);
1767046Sahrens 		if (err)
1777046Sahrens 			goto out;
1787046Sahrens 		err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
1797046Sahrens 		    DMU_POOL_SCRUB_ERRORS, sizeof (uint64_t), 1,
1807046Sahrens 		    &spa->spa_scrub_errors);
1817046Sahrens 		if (err)
1827046Sahrens 			goto out;
1837046Sahrens 		if (spa_version(spa) < SPA_VERSION_DSL_SCRUB) {
1847046Sahrens 			/*
1857046Sahrens 			 * A new-type scrub was in progress on an old
1867046Sahrens 			 * pool.  Restart from the beginning, since the
1877046Sahrens 			 * old software may have changed the pool in the
1887046Sahrens 			 * meantime.
1897046Sahrens 			 */
1907046Sahrens 			dsl_pool_scrub_restart(dp);
1917046Sahrens 		}
1927046Sahrens 	} else {
1937046Sahrens 		/*
1947046Sahrens 		 * It's OK if there is no scrub in progress (and if
1957046Sahrens 		 * there was an I/O error, ignore it).
1967046Sahrens 		 */
1977046Sahrens 		err = 0;
1987046Sahrens 	}
1997046Sahrens 
2001544Seschrock out:
201789Sahrens 	rw_exit(&dp->dp_config_rwlock);
2021544Seschrock 	if (err)
2031544Seschrock 		dsl_pool_close(dp);
2041544Seschrock 	else
2051544Seschrock 		*dpp = dp;
206789Sahrens 
2071544Seschrock 	return (err);
208789Sahrens }
209789Sahrens 
210789Sahrens void
211789Sahrens dsl_pool_close(dsl_pool_t *dp)
212789Sahrens {
2137046Sahrens 	/* drop our references from dsl_pool_open() */
2147046Sahrens 
2157046Sahrens 	/*
2167046Sahrens 	 * Since we held the origin_snap from "syncing" context (which
2177046Sahrens 	 * includes pool-opening context), it actually only got a "ref"
2187046Sahrens 	 * and not a hold, so just drop that here.
2197046Sahrens 	 */
2207046Sahrens 	if (dp->dp_origin_snap)
2217046Sahrens 		dsl_dataset_drop_ref(dp->dp_origin_snap, dp);
2221544Seschrock 	if (dp->dp_mos_dir)
2231544Seschrock 		dsl_dir_close(dp->dp_mos_dir, dp);
2241544Seschrock 	if (dp->dp_root_dir)
2251544Seschrock 		dsl_dir_close(dp->dp_root_dir, dp);
226789Sahrens 
227789Sahrens 	/* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
2281544Seschrock 	if (dp->dp_meta_objset)
22910298SMatthew.Ahrens@Sun.COM 		dmu_objset_evict(dp->dp_meta_objset);
230789Sahrens 
231789Sahrens 	txg_list_destroy(&dp->dp_dirty_datasets);
232789Sahrens 	txg_list_destroy(&dp->dp_dirty_dirs);
2335367Sahrens 	list_destroy(&dp->dp_synced_datasets);
234789Sahrens 
2355642Smaybee 	arc_flush(dp->dp_spa);
236789Sahrens 	txg_fini(dp);
2372856Snd150628 	rw_destroy(&dp->dp_config_rwlock);
2386245Smaybee 	mutex_destroy(&dp->dp_lock);
2397046Sahrens 	mutex_destroy(&dp->dp_scrub_cancel_lock);
2409321SNeil.Perrin@Sun.COM 	taskq_destroy(dp->dp_vnrele_taskq);
2417837SMatthew.Ahrens@Sun.COM 	if (dp->dp_blkstats)
2427837SMatthew.Ahrens@Sun.COM 		kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
243789Sahrens 	kmem_free(dp, sizeof (dsl_pool_t));
244789Sahrens }
245789Sahrens 
246789Sahrens dsl_pool_t *
2477184Stimh dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)
248789Sahrens {
249789Sahrens 	int err;
250789Sahrens 	dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
251789Sahrens 	dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
25210298SMatthew.Ahrens@Sun.COM 	objset_t *os;
2537046Sahrens 	dsl_dataset_t *ds;
2547046Sahrens 	uint64_t dsobj;
2557046Sahrens 
2567046Sahrens 	/* create and open the MOS (meta-objset) */
25710298SMatthew.Ahrens@Sun.COM 	dp->dp_meta_objset = dmu_objset_create_impl(spa,
25810298SMatthew.Ahrens@Sun.COM 	    NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);
259789Sahrens 
260789Sahrens 	/* create the pool directory */
261789Sahrens 	err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
262789Sahrens 	    DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
263789Sahrens 	ASSERT3U(err, ==, 0);
264789Sahrens 
265789Sahrens 	/* create and open the root dir */
2667046Sahrens 	dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);
2671544Seschrock 	VERIFY(0 == dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
2681544Seschrock 	    NULL, dp, &dp->dp_root_dir));
269789Sahrens 
270789Sahrens 	/* create and open the meta-objset dir */
2717046Sahrens 	(void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);
2727046Sahrens 	VERIFY(0 == dsl_pool_open_special_dir(dp,
2737046Sahrens 	    MOS_DIR_NAME, &dp->dp_mos_dir));
2747046Sahrens 
2757046Sahrens 	if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB)
2767046Sahrens 		dsl_pool_create_origin(dp, tx);
2777046Sahrens 
2787046Sahrens 	/* create the root dataset */
2797046Sahrens 	dsobj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);
2807046Sahrens 
2817046Sahrens 	/* create the root objset */
2827046Sahrens 	VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
28310298SMatthew.Ahrens@Sun.COM 	os = dmu_objset_create_impl(dp->dp_spa, ds,
2847046Sahrens 	    dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx);
2857046Sahrens #ifdef _KERNEL
28610298SMatthew.Ahrens@Sun.COM 	zfs_create_fs(os, kcred, zplprops, tx);
2877046Sahrens #endif
2887046Sahrens 	dsl_dataset_rele(ds, FTAG);
289789Sahrens 
290789Sahrens 	dmu_tx_commit(tx);
291789Sahrens 
292789Sahrens 	return (dp);
293789Sahrens }
294789Sahrens 
295789Sahrens void
296789Sahrens dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
297789Sahrens {
2983547Smaybee 	zio_t *zio;
299789Sahrens 	dmu_tx_t *tx;
3003547Smaybee 	dsl_dir_t *dd;
3013547Smaybee 	dsl_dataset_t *ds;
3023547Smaybee 	dsl_sync_task_group_t *dstg;
30310298SMatthew.Ahrens@Sun.COM 	objset_t *mos = dp->dp_meta_objset;
3047468SMark.Maybee@Sun.COM 	hrtime_t start, write_time;
3057468SMark.Maybee@Sun.COM 	uint64_t data_written;
3063547Smaybee 	int err;
307789Sahrens 
308789Sahrens 	tx = dmu_tx_create_assigned(dp, txg);
309789Sahrens 
3107468SMark.Maybee@Sun.COM 	dp->dp_read_overhead = 0;
3119366SMark.Maybee@Sun.COM 	start = gethrtime();
3129396SMatthew.Ahrens@Sun.COM 
3133547Smaybee 	zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
3143547Smaybee 	while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {
3159396SMatthew.Ahrens@Sun.COM 		/*
3169396SMatthew.Ahrens@Sun.COM 		 * We must not sync any non-MOS datasets twice, because
3179396SMatthew.Ahrens@Sun.COM 		 * we may have taken a snapshot of them.  However, we
3189396SMatthew.Ahrens@Sun.COM 		 * may sync newly-created datasets on pass 2.
3199396SMatthew.Ahrens@Sun.COM 		 */
3209396SMatthew.Ahrens@Sun.COM 		ASSERT(!list_link_active(&ds->ds_synced_link));
3219396SMatthew.Ahrens@Sun.COM 		list_insert_tail(&dp->dp_synced_datasets, ds);
3223547Smaybee 		dsl_dataset_sync(ds, zio, tx);
3233547Smaybee 	}
3247468SMark.Maybee@Sun.COM 	DTRACE_PROBE(pool_sync__1setup);
3259396SMatthew.Ahrens@Sun.COM 	err = zio_wait(zio);
3267468SMark.Maybee@Sun.COM 
3277468SMark.Maybee@Sun.COM 	write_time = gethrtime() - start;
3283547Smaybee 	ASSERT(err == 0);
3297468SMark.Maybee@Sun.COM 	DTRACE_PROBE(pool_sync__2rootzio);
330789Sahrens 
3319396SMatthew.Ahrens@Sun.COM 	for (ds = list_head(&dp->dp_synced_datasets); ds;
3329396SMatthew.Ahrens@Sun.COM 	    ds = list_next(&dp->dp_synced_datasets, ds))
33310298SMatthew.Ahrens@Sun.COM 		dmu_objset_do_userquota_callbacks(ds->ds_objset, tx);
3349396SMatthew.Ahrens@Sun.COM 
3359396SMatthew.Ahrens@Sun.COM 	/*
3369396SMatthew.Ahrens@Sun.COM 	 * Sync the datasets again to push out the changes due to
3379396SMatthew.Ahrens@Sun.COM 	 * userquota updates.  This must be done before we process the
3389396SMatthew.Ahrens@Sun.COM 	 * sync tasks, because that could cause a snapshot of a dataset
3399396SMatthew.Ahrens@Sun.COM 	 * whose ds_bp will be rewritten when we do this 2nd sync.
3409396SMatthew.Ahrens@Sun.COM 	 */
3419396SMatthew.Ahrens@Sun.COM 	zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
3429396SMatthew.Ahrens@Sun.COM 	while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {
3439396SMatthew.Ahrens@Sun.COM 		ASSERT(list_link_active(&ds->ds_synced_link));
3449396SMatthew.Ahrens@Sun.COM 		dmu_buf_rele(ds->ds_dbuf, ds);
3459396SMatthew.Ahrens@Sun.COM 		dsl_dataset_sync(ds, zio, tx);
3469396SMatthew.Ahrens@Sun.COM 	}
3479396SMatthew.Ahrens@Sun.COM 	err = zio_wait(zio);
3489396SMatthew.Ahrens@Sun.COM 
34910922SJeff.Bonwick@Sun.COM 	/*
35010922SJeff.Bonwick@Sun.COM 	 * If anything was added to a deadlist during a zio done callback,
35110922SJeff.Bonwick@Sun.COM 	 * it had to be put on the deferred queue.  Enqueue it for real now.
35210922SJeff.Bonwick@Sun.COM 	 */
35310922SJeff.Bonwick@Sun.COM 	for (ds = list_head(&dp->dp_synced_datasets); ds;
35410922SJeff.Bonwick@Sun.COM 	    ds = list_next(&dp->dp_synced_datasets, ds))
35510922SJeff.Bonwick@Sun.COM 		bplist_sync(&ds->ds_deadlist,
35610922SJeff.Bonwick@Sun.COM 		    bplist_enqueue_cb, &ds->ds_deadlist, tx);
35710922SJeff.Bonwick@Sun.COM 
3589396SMatthew.Ahrens@Sun.COM 	while (dstg = txg_list_remove(&dp->dp_sync_tasks, txg)) {
3599396SMatthew.Ahrens@Sun.COM 		/*
3609396SMatthew.Ahrens@Sun.COM 		 * No more sync tasks should have been added while we
3619396SMatthew.Ahrens@Sun.COM 		 * were syncing.
3629396SMatthew.Ahrens@Sun.COM 		 */
3639396SMatthew.Ahrens@Sun.COM 		ASSERT(spa_sync_pass(dp->dp_spa) == 1);
3643547Smaybee 		dsl_sync_task_group_sync(dstg, tx);
3659396SMatthew.Ahrens@Sun.COM 	}
3667468SMark.Maybee@Sun.COM 	DTRACE_PROBE(pool_sync__3task);
3677468SMark.Maybee@Sun.COM 
3687468SMark.Maybee@Sun.COM 	start = gethrtime();
3693547Smaybee 	while (dd = txg_list_remove(&dp->dp_dirty_dirs, txg))
3703547Smaybee 		dsl_dir_sync(dd, tx);
3717468SMark.Maybee@Sun.COM 	write_time += gethrtime() - start;
372789Sahrens 
3737046Sahrens 	if (spa_sync_pass(dp->dp_spa) == 1)
3747046Sahrens 		dsl_pool_scrub_sync(dp, tx);
3757046Sahrens 
3767468SMark.Maybee@Sun.COM 	start = gethrtime();
37710298SMatthew.Ahrens@Sun.COM 	if (list_head(&mos->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||
37810298SMatthew.Ahrens@Sun.COM 	    list_head(&mos->os_free_dnodes[txg & TXG_MASK]) != NULL) {
3793547Smaybee 		zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
38010298SMatthew.Ahrens@Sun.COM 		dmu_objset_sync(mos, zio, tx);
3813547Smaybee 		err = zio_wait(zio);
3823547Smaybee 		ASSERT(err == 0);
383789Sahrens 		dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
384789Sahrens 		spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
385789Sahrens 	}
3867468SMark.Maybee@Sun.COM 	write_time += gethrtime() - start;
3877468SMark.Maybee@Sun.COM 	DTRACE_PROBE2(pool_sync__4io, hrtime_t, write_time,
3887468SMark.Maybee@Sun.COM 	    hrtime_t, dp->dp_read_overhead);
3897468SMark.Maybee@Sun.COM 	write_time -= dp->dp_read_overhead;
390789Sahrens 
391789Sahrens 	dmu_tx_commit(tx);
3927468SMark.Maybee@Sun.COM 
3937468SMark.Maybee@Sun.COM 	data_written = dp->dp_space_towrite[txg & TXG_MASK];
3947468SMark.Maybee@Sun.COM 	dp->dp_space_towrite[txg & TXG_MASK] = 0;
3957468SMark.Maybee@Sun.COM 	ASSERT(dp->dp_tempreserved[txg & TXG_MASK] == 0);
3967468SMark.Maybee@Sun.COM 
3977468SMark.Maybee@Sun.COM 	/*
3987468SMark.Maybee@Sun.COM 	 * If the write limit max has not been explicitly set, set it
3997468SMark.Maybee@Sun.COM 	 * to a fraction of available physical memory (default 1/8th).
4007468SMark.Maybee@Sun.COM 	 * Note that we must inflate the limit because the spa
4017468SMark.Maybee@Sun.COM 	 * inflates write sizes to account for data replication.
4027468SMark.Maybee@Sun.COM 	 * Check this each sync phase to catch changing memory size.
4037468SMark.Maybee@Sun.COM 	 */
4047468SMark.Maybee@Sun.COM 	if (physmem != old_physmem && zfs_write_limit_shift) {
4057468SMark.Maybee@Sun.COM 		mutex_enter(&zfs_write_limit_lock);
4067468SMark.Maybee@Sun.COM 		old_physmem = physmem;
4077468SMark.Maybee@Sun.COM 		zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift;
4087468SMark.Maybee@Sun.COM 		zfs_write_limit_inflated = MAX(zfs_write_limit_min,
4097468SMark.Maybee@Sun.COM 		    spa_get_asize(dp->dp_spa, zfs_write_limit_max));
4107468SMark.Maybee@Sun.COM 		mutex_exit(&zfs_write_limit_lock);
4117468SMark.Maybee@Sun.COM 	}
4127468SMark.Maybee@Sun.COM 
4137468SMark.Maybee@Sun.COM 	/*
4147468SMark.Maybee@Sun.COM 	 * Attempt to keep the sync time consistent by adjusting the
4157468SMark.Maybee@Sun.COM 	 * amount of write traffic allowed into each transaction group.
4167468SMark.Maybee@Sun.COM 	 * Weight the throughput calculation towards the current value:
4177468SMark.Maybee@Sun.COM 	 * 	thru = 3/4 old_thru + 1/4 new_thru
4187468SMark.Maybee@Sun.COM 	 */
4197468SMark.Maybee@Sun.COM 	ASSERT(zfs_write_limit_min > 0);
4207468SMark.Maybee@Sun.COM 	if (data_written > zfs_write_limit_min / 8 && write_time > 0) {
4217468SMark.Maybee@Sun.COM 		uint64_t throughput = (data_written * NANOSEC) / write_time;
4227468SMark.Maybee@Sun.COM 		if (dp->dp_throughput)
4237468SMark.Maybee@Sun.COM 			dp->dp_throughput = throughput / 4 +
4247468SMark.Maybee@Sun.COM 			    3 * dp->dp_throughput / 4;
4257468SMark.Maybee@Sun.COM 		else
4267468SMark.Maybee@Sun.COM 			dp->dp_throughput = throughput;
4277468SMark.Maybee@Sun.COM 		dp->dp_write_limit = MIN(zfs_write_limit_inflated,
4287468SMark.Maybee@Sun.COM 		    MAX(zfs_write_limit_min,
4297468SMark.Maybee@Sun.COM 		    dp->dp_throughput * zfs_txg_synctime));
4307468SMark.Maybee@Sun.COM 	}
431789Sahrens }
432789Sahrens 
433789Sahrens void
43410922SJeff.Bonwick@Sun.COM dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)
435789Sahrens {
436789Sahrens 	dsl_dataset_t *ds;
43710922SJeff.Bonwick@Sun.COM 	objset_t *os;
438789Sahrens 
4395367Sahrens 	while (ds = list_head(&dp->dp_synced_datasets)) {
4405367Sahrens 		list_remove(&dp->dp_synced_datasets, ds);
44110922SJeff.Bonwick@Sun.COM 		os = ds->ds_objset;
44210922SJeff.Bonwick@Sun.COM 		zil_clean(os->os_zil);
44310922SJeff.Bonwick@Sun.COM 		ASSERT(!dmu_objset_is_dirty(os, txg));
4443897Smaybee 		dmu_buf_rele(ds->ds_dbuf, ds);
445789Sahrens 	}
44610922SJeff.Bonwick@Sun.COM 	ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));
447789Sahrens }
448789Sahrens 
4493547Smaybee /*
4503547Smaybee  * TRUE if the current thread is the tx_sync_thread or if we
4513547Smaybee  * are being called from SPA context during pool initialization.
4523547Smaybee  */
453789Sahrens int
454789Sahrens dsl_pool_sync_context(dsl_pool_t *dp)
455789Sahrens {
456789Sahrens 	return (curthread == dp->dp_tx.tx_sync_thread ||
4573547Smaybee 	    spa_get_dsl(dp->dp_spa) == NULL);
458789Sahrens }
459789Sahrens 
460789Sahrens uint64_t
461789Sahrens dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree)
462789Sahrens {
463789Sahrens 	uint64_t space, resv;
464789Sahrens 
465789Sahrens 	/*
4661775Sbillm 	 * Reserve about 1.6% (1/64), or at least 32MB, for allocation
467789Sahrens 	 * efficiency.
468789Sahrens 	 * XXX The intent log is not accounted for, so it must fit
469789Sahrens 	 * within this slop.
470789Sahrens 	 *
471789Sahrens 	 * If we're trying to assess whether it's OK to do a free,
472789Sahrens 	 * cut the reservation in half to allow forward progress
473789Sahrens 	 * (e.g. make it possible to rm(1) files from a full pool).
474789Sahrens 	 */
475*10956SGeorge.Wilson@Sun.COM 	space = spa_get_dspace(dp->dp_spa);
4761775Sbillm 	resv = MAX(space >> 6, SPA_MINDEVSIZE >> 1);
477789Sahrens 	if (netfree)
478789Sahrens 		resv >>= 1;
479789Sahrens 
480789Sahrens 	return (space - resv);
481789Sahrens }
4826245Smaybee 
4836245Smaybee int
4846245Smaybee dsl_pool_tempreserve_space(dsl_pool_t *dp, uint64_t space, dmu_tx_t *tx)
4856245Smaybee {
4866245Smaybee 	uint64_t reserved = 0;
4876245Smaybee 	uint64_t write_limit = (zfs_write_limit_override ?
4886245Smaybee 	    zfs_write_limit_override : dp->dp_write_limit);
4896245Smaybee 
4906245Smaybee 	if (zfs_no_write_throttle) {
4916643Seschrock 		atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK],
4926643Seschrock 		    space);
4936245Smaybee 		return (0);
4946245Smaybee 	}
4956245Smaybee 
4966245Smaybee 	/*
4976245Smaybee 	 * Check to see if we have exceeded the maximum allowed IO for
4986245Smaybee 	 * this transaction group.  We can do this without locks since
4996245Smaybee 	 * a little slop here is ok.  Note that we do the reserved check
5006245Smaybee 	 * with only half the requested reserve: this is because the
5016245Smaybee 	 * reserve requests are worst-case, and we really don't want to
5026245Smaybee 	 * throttle based off of worst-case estimates.
5036245Smaybee 	 */
5046245Smaybee 	if (write_limit > 0) {
5056245Smaybee 		reserved = dp->dp_space_towrite[tx->tx_txg & TXG_MASK]
5066245Smaybee 		    + dp->dp_tempreserved[tx->tx_txg & TXG_MASK] / 2;
5076245Smaybee 
5086245Smaybee 		if (reserved && reserved > write_limit)
5096245Smaybee 			return (ERESTART);
5106245Smaybee 	}
5116245Smaybee 
5126245Smaybee 	atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], space);
5136245Smaybee 
5146245Smaybee 	/*
5156245Smaybee 	 * If this transaction group is over 7/8ths capacity, delay
5166245Smaybee 	 * the caller 1 clock tick.  This will slow down the "fill"
5176245Smaybee 	 * rate until the sync process can catch up with us.
5186245Smaybee 	 */
5196740Sgw25295 	if (reserved && reserved > (write_limit - (write_limit >> 3)))
5206245Smaybee 		txg_delay(dp, tx->tx_txg, 1);
5216245Smaybee 
5226245Smaybee 	return (0);
5236245Smaybee }
5246245Smaybee 
5256245Smaybee void
5266245Smaybee dsl_pool_tempreserve_clear(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
5276245Smaybee {
5286245Smaybee 	ASSERT(dp->dp_tempreserved[tx->tx_txg & TXG_MASK] >= space);
5296245Smaybee 	atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], -space);
5306245Smaybee }
5316245Smaybee 
5326245Smaybee void
5336245Smaybee dsl_pool_memory_pressure(dsl_pool_t *dp)
5346245Smaybee {
5356245Smaybee 	uint64_t space_inuse = 0;
5366245Smaybee 	int i;
5376245Smaybee 
5386245Smaybee 	if (dp->dp_write_limit == zfs_write_limit_min)
5396245Smaybee 		return;
5406245Smaybee 
5416245Smaybee 	for (i = 0; i < TXG_SIZE; i++) {
5426245Smaybee 		space_inuse += dp->dp_space_towrite[i];
5436245Smaybee 		space_inuse += dp->dp_tempreserved[i];
5446245Smaybee 	}
5456245Smaybee 	dp->dp_write_limit = MAX(zfs_write_limit_min,
5466245Smaybee 	    MIN(dp->dp_write_limit, space_inuse / 4));
5476245Smaybee }
5486245Smaybee 
5496245Smaybee void
5506245Smaybee dsl_pool_willuse_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
5516245Smaybee {
5526245Smaybee 	if (space > 0) {
5536245Smaybee 		mutex_enter(&dp->dp_lock);
5546245Smaybee 		dp->dp_space_towrite[tx->tx_txg & TXG_MASK] += space;
5556245Smaybee 		mutex_exit(&dp->dp_lock);
5566245Smaybee 	}
5576245Smaybee }
5587046Sahrens 
5597046Sahrens /* ARGSUSED */
5607046Sahrens static int
5617046Sahrens upgrade_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
5627046Sahrens {
5637046Sahrens 	dmu_tx_t *tx = arg;
5647046Sahrens 	dsl_dataset_t *ds, *prev = NULL;
5657046Sahrens 	int err;
5667046Sahrens 	dsl_pool_t *dp = spa_get_dsl(spa);
5677046Sahrens 
5687046Sahrens 	err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
5697046Sahrens 	if (err)
5707046Sahrens 		return (err);
5717046Sahrens 
5727046Sahrens 	while (ds->ds_phys->ds_prev_snap_obj != 0) {
5737046Sahrens 		err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
5747046Sahrens 		    FTAG, &prev);
5757046Sahrens 		if (err) {
5767046Sahrens 			dsl_dataset_rele(ds, FTAG);
5777046Sahrens 			return (err);
5787046Sahrens 		}
5797046Sahrens 
5807046Sahrens 		if (prev->ds_phys->ds_next_snap_obj != ds->ds_object)
5817046Sahrens 			break;
5827046Sahrens 		dsl_dataset_rele(ds, FTAG);
5837046Sahrens 		ds = prev;
5847046Sahrens 		prev = NULL;
5857046Sahrens 	}
5867046Sahrens 
5877046Sahrens 	if (prev == NULL) {
5887046Sahrens 		prev = dp->dp_origin_snap;
5897046Sahrens 
5907046Sahrens 		/*
5917046Sahrens 		 * The $ORIGIN can't have any data, or the accounting
5927046Sahrens 		 * will be wrong.
5937046Sahrens 		 */
5947046Sahrens 		ASSERT(prev->ds_phys->ds_bp.blk_birth == 0);
5957046Sahrens 
5967046Sahrens 		/* The origin doesn't get attached to itself */
5977046Sahrens 		if (ds->ds_object == prev->ds_object) {
5987046Sahrens 			dsl_dataset_rele(ds, FTAG);
5997046Sahrens 			return (0);
6007046Sahrens 		}
6017046Sahrens 
6027046Sahrens 		dmu_buf_will_dirty(ds->ds_dbuf, tx);
6037046Sahrens 		ds->ds_phys->ds_prev_snap_obj = prev->ds_object;
6047046Sahrens 		ds->ds_phys->ds_prev_snap_txg = prev->ds_phys->ds_creation_txg;
6057046Sahrens 
6067046Sahrens 		dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
6077046Sahrens 		ds->ds_dir->dd_phys->dd_origin_obj = prev->ds_object;
6087046Sahrens 
6097046Sahrens 		dmu_buf_will_dirty(prev->ds_dbuf, tx);
6107046Sahrens 		prev->ds_phys->ds_num_children++;
6117046Sahrens 
6127046Sahrens 		if (ds->ds_phys->ds_next_snap_obj == 0) {
6137046Sahrens 			ASSERT(ds->ds_prev == NULL);
6147046Sahrens 			VERIFY(0 == dsl_dataset_hold_obj(dp,
6157046Sahrens 			    ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev));
6167046Sahrens 		}
6177046Sahrens 	}
6187046Sahrens 
6197046Sahrens 	ASSERT(ds->ds_dir->dd_phys->dd_origin_obj == prev->ds_object);
6207046Sahrens 	ASSERT(ds->ds_phys->ds_prev_snap_obj == prev->ds_object);
6217046Sahrens 
6227046Sahrens 	if (prev->ds_phys->ds_next_clones_obj == 0) {
62310801SMatthew.Ahrens@Sun.COM 		dmu_buf_will_dirty(prev->ds_dbuf, tx);
6247046Sahrens 		prev->ds_phys->ds_next_clones_obj =
6257046Sahrens 		    zap_create(dp->dp_meta_objset,
6267046Sahrens 		    DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
6277046Sahrens 	}
6287046Sahrens 	VERIFY(0 == zap_add_int(dp->dp_meta_objset,
6297046Sahrens 	    prev->ds_phys->ds_next_clones_obj, ds->ds_object, tx));
6307046Sahrens 
6317046Sahrens 	dsl_dataset_rele(ds, FTAG);
6327046Sahrens 	if (prev != dp->dp_origin_snap)
6337046Sahrens 		dsl_dataset_rele(prev, FTAG);
6347046Sahrens 	return (0);
6357046Sahrens }
6367046Sahrens 
6377046Sahrens void
6387046Sahrens dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx)
6397046Sahrens {
6407046Sahrens 	ASSERT(dmu_tx_is_syncing(tx));
6417046Sahrens 	ASSERT(dp->dp_origin_snap != NULL);
6427046Sahrens 
64310801SMatthew.Ahrens@Sun.COM 	VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL, upgrade_clones_cb,
64410801SMatthew.Ahrens@Sun.COM 	    tx, DS_FIND_CHILDREN));
6457046Sahrens }
6467046Sahrens 
6477046Sahrens void
6487046Sahrens dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
6497046Sahrens {
6507046Sahrens 	uint64_t dsobj;
6517046Sahrens 	dsl_dataset_t *ds;
6527046Sahrens 
6537046Sahrens 	ASSERT(dmu_tx_is_syncing(tx));
6547046Sahrens 	ASSERT(dp->dp_origin_snap == NULL);
6557046Sahrens 
6567046Sahrens 	/* create the origin dir, ds, & snap-ds */
6577046Sahrens 	rw_enter(&dp->dp_config_rwlock, RW_WRITER);
6587046Sahrens 	dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME,
6597046Sahrens 	    NULL, 0, kcred, tx);
6607046Sahrens 	VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
6617046Sahrens 	dsl_dataset_snapshot_sync(ds, ORIGIN_DIR_NAME, kcred, tx);
6627046Sahrens 	VERIFY(0 == dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
6637046Sahrens 	    dp, &dp->dp_origin_snap));
6647046Sahrens 	dsl_dataset_rele(ds, FTAG);
6657046Sahrens 	rw_exit(&dp->dp_config_rwlock);
6667046Sahrens }
6679321SNeil.Perrin@Sun.COM 
6689321SNeil.Perrin@Sun.COM taskq_t *
6699321SNeil.Perrin@Sun.COM dsl_pool_vnrele_taskq(dsl_pool_t *dp)
6709321SNeil.Perrin@Sun.COM {
6719321SNeil.Perrin@Sun.COM 	return (dp->dp_vnrele_taskq);
6729321SNeil.Perrin@Sun.COM }
67310342Schris.kirby@sun.com 
67410342Schris.kirby@sun.com /*
67510342Schris.kirby@sun.com  * Walk through the pool-wide zap object of temporary snapshot user holds
67610342Schris.kirby@sun.com  * and release them.
67710342Schris.kirby@sun.com  */
67810342Schris.kirby@sun.com void
67910342Schris.kirby@sun.com dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp)
68010342Schris.kirby@sun.com {
68110342Schris.kirby@sun.com 	zap_attribute_t za;
68210342Schris.kirby@sun.com 	zap_cursor_t zc;
68310342Schris.kirby@sun.com 	objset_t *mos = dp->dp_meta_objset;
68410342Schris.kirby@sun.com 	uint64_t zapobj = dp->dp_tmp_userrefs_obj;
68510342Schris.kirby@sun.com 
68610342Schris.kirby@sun.com 	if (zapobj == 0)
68710342Schris.kirby@sun.com 		return;
68810342Schris.kirby@sun.com 	ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
68910342Schris.kirby@sun.com 
69010342Schris.kirby@sun.com 	for (zap_cursor_init(&zc, mos, zapobj);
69110342Schris.kirby@sun.com 	    zap_cursor_retrieve(&zc, &za) == 0;
69210342Schris.kirby@sun.com 	    zap_cursor_advance(&zc)) {
69310342Schris.kirby@sun.com 		char *htag;
69410342Schris.kirby@sun.com 		uint64_t dsobj;
69510342Schris.kirby@sun.com 
69610342Schris.kirby@sun.com 		htag = strchr(za.za_name, '-');
69710342Schris.kirby@sun.com 		*htag = '\0';
69810342Schris.kirby@sun.com 		++htag;
69910342Schris.kirby@sun.com 		dsobj = strtonum(za.za_name, NULL);
70010342Schris.kirby@sun.com 		(void) dsl_dataset_user_release_tmp(dp, dsobj, htag);
70110342Schris.kirby@sun.com 	}
70210342Schris.kirby@sun.com 	zap_cursor_fini(&zc);
70310342Schris.kirby@sun.com }
70410342Schris.kirby@sun.com 
70510342Schris.kirby@sun.com /*
70610342Schris.kirby@sun.com  * Create the pool-wide zap object for storing temporary snapshot holds.
70710342Schris.kirby@sun.com  */
70810342Schris.kirby@sun.com void
70910342Schris.kirby@sun.com dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx)
71010342Schris.kirby@sun.com {
71110342Schris.kirby@sun.com 	objset_t *mos = dp->dp_meta_objset;
71210342Schris.kirby@sun.com 
71310342Schris.kirby@sun.com 	ASSERT(dp->dp_tmp_userrefs_obj == 0);
71410342Schris.kirby@sun.com 	ASSERT(dmu_tx_is_syncing(tx));
71510342Schris.kirby@sun.com 
71610342Schris.kirby@sun.com 	dp->dp_tmp_userrefs_obj = zap_create(mos, DMU_OT_USERREFS,
71710342Schris.kirby@sun.com 	    DMU_OT_NONE, 0, tx);
71810342Schris.kirby@sun.com 
71910342Schris.kirby@sun.com 	VERIFY(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS,
72010342Schris.kirby@sun.com 	    sizeof (uint64_t), 1, &dp->dp_tmp_userrefs_obj, tx) == 0);
72110342Schris.kirby@sun.com }
72210342Schris.kirby@sun.com 
72310342Schris.kirby@sun.com static int
72410342Schris.kirby@sun.com dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj,
72510951SChris.Kirby@sun.com     const char *tag, uint64_t *now, dmu_tx_t *tx, boolean_t holding)
72610342Schris.kirby@sun.com {
72710342Schris.kirby@sun.com 	objset_t *mos = dp->dp_meta_objset;
72810342Schris.kirby@sun.com 	uint64_t zapobj = dp->dp_tmp_userrefs_obj;
72910342Schris.kirby@sun.com 	char *name;
73010342Schris.kirby@sun.com 	int error;
73110342Schris.kirby@sun.com 
73210342Schris.kirby@sun.com 	ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
73310342Schris.kirby@sun.com 	ASSERT(dmu_tx_is_syncing(tx));
73410342Schris.kirby@sun.com 
73510342Schris.kirby@sun.com 	/*
73610342Schris.kirby@sun.com 	 * If the pool was created prior to SPA_VERSION_USERREFS, the
73710342Schris.kirby@sun.com 	 * zap object for temporary holds might not exist yet.
73810342Schris.kirby@sun.com 	 */
73910342Schris.kirby@sun.com 	if (zapobj == 0) {
74010342Schris.kirby@sun.com 		if (holding) {
74110342Schris.kirby@sun.com 			dsl_pool_user_hold_create_obj(dp, tx);
74210342Schris.kirby@sun.com 			zapobj = dp->dp_tmp_userrefs_obj;
74310342Schris.kirby@sun.com 		} else {
74410342Schris.kirby@sun.com 			return (ENOENT);
74510342Schris.kirby@sun.com 		}
74610342Schris.kirby@sun.com 	}
74710342Schris.kirby@sun.com 
74810342Schris.kirby@sun.com 	name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag);
74910342Schris.kirby@sun.com 	if (holding)
75010951SChris.Kirby@sun.com 		error = zap_add(mos, zapobj, name, 8, 1, now, tx);
75110342Schris.kirby@sun.com 	else
75210342Schris.kirby@sun.com 		error = zap_remove(mos, zapobj, name, tx);
75310342Schris.kirby@sun.com 	strfree(name);
75410342Schris.kirby@sun.com 
75510342Schris.kirby@sun.com 	return (error);
75610342Schris.kirby@sun.com }
75710342Schris.kirby@sun.com 
75810342Schris.kirby@sun.com /*
75910342Schris.kirby@sun.com  * Add a temporary hold for the given dataset object and tag.
76010342Schris.kirby@sun.com  */
76110342Schris.kirby@sun.com int
76210342Schris.kirby@sun.com dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
76310951SChris.Kirby@sun.com     uint64_t *now, dmu_tx_t *tx)
76410342Schris.kirby@sun.com {
76510951SChris.Kirby@sun.com 	return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE));
76610342Schris.kirby@sun.com }
76710342Schris.kirby@sun.com 
76810342Schris.kirby@sun.com /*
76910342Schris.kirby@sun.com  * Release a temporary hold for the given dataset object and tag.
77010342Schris.kirby@sun.com  */
77110342Schris.kirby@sun.com int
77210342Schris.kirby@sun.com dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
77310342Schris.kirby@sun.com     dmu_tx_t *tx)
77410342Schris.kirby@sun.com {
77510342Schris.kirby@sun.com 	return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, NULL,
77610342Schris.kirby@sun.com 	    tx, B_FALSE));
77710342Schris.kirby@sun.com }
778