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-rw-r--r--module/zfs/dsl_pool.c350
1 files changed, 273 insertions, 77 deletions
diff --git a/module/zfs/dsl_pool.c b/module/zfs/dsl_pool.c
index 2c5dfca53..2cd21a102 100644
--- a/module/zfs/dsl_pool.c
+++ b/module/zfs/dsl_pool.c
@@ -19,14 +19,16 @@
* CDDL HEADER END
*/
/*
- * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
- * Use is subject to license terms.
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
*/
#include <sys/dsl_pool.h>
#include <sys/dsl_dataset.h>
+#include <sys/dsl_prop.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_synctask.h>
+#include <sys/dsl_scan.h>
+#include <sys/dnode.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/arc.h>
@@ -36,10 +38,11 @@
#include <sys/fs/zfs.h>
#include <sys/zfs_znode.h>
#include <sys/spa_impl.h>
+#include <sys/dsl_deadlist.h>
int zfs_no_write_throttle = 0;
int zfs_write_limit_shift = 3; /* 1/8th of physical memory */
-int zfs_txg_synctime = 5; /* target secs to sync a txg */
+int zfs_txg_synctime_ms = 5000; /* target millisecs to sync a txg */
uint64_t zfs_write_limit_min = 32 << 20; /* min write limit is 32MB */
uint64_t zfs_write_limit_max = 0; /* max data payload per txg */
@@ -50,7 +53,7 @@ kmutex_t zfs_write_limit_lock;
static pgcnt_t old_physmem = 0;
-static int
+int
dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
{
uint64_t obj;
@@ -88,7 +91,6 @@ dsl_pool_open_impl(spa_t *spa, uint64_t txg)
offsetof(dsl_dataset_t, ds_synced_link));
mutex_init(&dp->dp_lock, NULL, MUTEX_DEFAULT, NULL);
- mutex_init(&dp->dp_scrub_cancel_lock, NULL, MUTEX_DEFAULT, NULL);
dp->dp_vnrele_taskq = taskq_create("zfs_vn_rele_taskq", 1, minclsyspri,
1, 4, 0);
@@ -103,13 +105,13 @@ dsl_pool_open(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
dsl_dir_t *dd;
dsl_dataset_t *ds;
- objset_impl_t *osi;
+ uint64_t obj;
rw_enter(&dp->dp_config_rwlock, RW_WRITER);
- err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp, &osi);
+ err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,
+ &dp->dp_meta_objset);
if (err)
goto out;
- dp->dp_meta_objset = &osi->os;
err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
@@ -143,53 +145,30 @@ dsl_pool_open(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
goto out;
}
- /* get scrub status */
- err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
- DMU_POOL_SCRUB_FUNC, sizeof (uint32_t), 1,
- &dp->dp_scrub_func);
- if (err == 0) {
- err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
- DMU_POOL_SCRUB_QUEUE, sizeof (uint64_t), 1,
- &dp->dp_scrub_queue_obj);
- if (err)
- goto out;
- err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
- DMU_POOL_SCRUB_MIN_TXG, sizeof (uint64_t), 1,
- &dp->dp_scrub_min_txg);
- if (err)
- goto out;
- err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
- DMU_POOL_SCRUB_MAX_TXG, sizeof (uint64_t), 1,
- &dp->dp_scrub_max_txg);
- if (err)
- goto out;
- err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
- DMU_POOL_SCRUB_BOOKMARK, sizeof (uint64_t), 4,
- &dp->dp_scrub_bookmark);
+ if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
+ err = dsl_pool_open_special_dir(dp, FREE_DIR_NAME,
+ &dp->dp_free_dir);
if (err)
goto out;
+
err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
- DMU_POOL_SCRUB_ERRORS, sizeof (uint64_t), 1,
- &spa->spa_scrub_errors);
+ DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj);
if (err)
goto out;
- if (spa_version(spa) < SPA_VERSION_DSL_SCRUB) {
- /*
- * A new-type scrub was in progress on an old
- * pool. Restart from the beginning, since the
- * old software may have changed the pool in the
- * meantime.
- */
- dsl_pool_scrub_restart(dp);
- }
- } else {
- /*
- * It's OK if there is no scrub in progress (and if
- * there was an I/O error, ignore it).
- */
- err = 0;
+ VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
+ dp->dp_meta_objset, obj));
}
+ err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+ DMU_POOL_TMP_USERREFS, sizeof (uint64_t), 1,
+ &dp->dp_tmp_userrefs_obj);
+ if (err == ENOENT)
+ err = 0;
+ if (err)
+ goto out;
+
+ err = dsl_scan_init(dp, txg);
+
out:
rw_exit(&dp->dp_config_rwlock);
if (err)
@@ -214,22 +193,27 @@ dsl_pool_close(dsl_pool_t *dp)
dsl_dataset_drop_ref(dp->dp_origin_snap, dp);
if (dp->dp_mos_dir)
dsl_dir_close(dp->dp_mos_dir, dp);
+ if (dp->dp_free_dir)
+ dsl_dir_close(dp->dp_free_dir, dp);
if (dp->dp_root_dir)
dsl_dir_close(dp->dp_root_dir, dp);
+ bpobj_close(&dp->dp_free_bpobj);
+
/* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
if (dp->dp_meta_objset)
- dmu_objset_evict(NULL, dp->dp_meta_objset->os);
+ dmu_objset_evict(dp->dp_meta_objset);
txg_list_destroy(&dp->dp_dirty_datasets);
+ txg_list_destroy(&dp->dp_sync_tasks);
txg_list_destroy(&dp->dp_dirty_dirs);
list_destroy(&dp->dp_synced_datasets);
arc_flush(dp->dp_spa);
txg_fini(dp);
+ dsl_scan_fini(dp);
rw_destroy(&dp->dp_config_rwlock);
mutex_destroy(&dp->dp_lock);
- mutex_destroy(&dp->dp_scrub_cancel_lock);
taskq_destroy(dp->dp_vnrele_taskq);
if (dp->dp_blkstats)
kmem_free(dp->dp_blkstats, sizeof (zfs_all_blkstats_t));
@@ -242,19 +226,22 @@ dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)
int err;
dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
dmu_tx_t *tx = dmu_tx_create_assigned(dp, txg);
- objset_impl_t *osip;
+ objset_t *os;
dsl_dataset_t *ds;
- uint64_t dsobj;
+ uint64_t obj;
/* create and open the MOS (meta-objset) */
- dp->dp_meta_objset = &dmu_objset_create_impl(spa,
- NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx)->os;
+ dp->dp_meta_objset = dmu_objset_create_impl(spa,
+ NULL, &dp->dp_meta_rootbp, DMU_OST_META, tx);
/* create the pool directory */
err = zap_create_claim(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_OT_OBJECT_DIRECTORY, DMU_OT_NONE, 0, tx);
ASSERT3U(err, ==, 0);
+ /* Initialize scan structures */
+ VERIFY3U(0, ==, dsl_scan_init(dp, txg));
+
/* create and open the root dir */
dp->dp_root_dir_obj = dsl_dir_create_sync(dp, NULL, NULL, tx);
VERIFY(0 == dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
@@ -265,18 +252,33 @@ dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)
VERIFY(0 == dsl_pool_open_special_dir(dp,
MOS_DIR_NAME, &dp->dp_mos_dir));
+ if (spa_version(spa) >= SPA_VERSION_DEADLISTS) {
+ /* create and open the free dir */
+ (void) dsl_dir_create_sync(dp, dp->dp_root_dir,
+ FREE_DIR_NAME, tx);
+ VERIFY(0 == dsl_pool_open_special_dir(dp,
+ FREE_DIR_NAME, &dp->dp_free_dir));
+
+ /* create and open the free_bplist */
+ obj = bpobj_alloc(dp->dp_meta_objset, SPA_MAXBLOCKSIZE, tx);
+ VERIFY(zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+ DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx) == 0);
+ VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
+ dp->dp_meta_objset, obj));
+ }
+
if (spa_version(spa) >= SPA_VERSION_DSL_SCRUB)
dsl_pool_create_origin(dp, tx);
/* create the root dataset */
- dsobj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);
+ obj = dsl_dataset_create_sync_dd(dp->dp_root_dir, NULL, 0, tx);
/* create the root objset */
- VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
- osip = dmu_objset_create_impl(dp->dp_spa, ds,
+ VERIFY(0 == dsl_dataset_hold_obj(dp, obj, FTAG, &ds));
+ os = dmu_objset_create_impl(dp->dp_spa, ds,
dsl_dataset_get_blkptr(ds), DMU_OST_ZFS, tx);
#ifdef _KERNEL
- zfs_create_fs(&osip->os, kcred, zplprops, tx);
+ zfs_create_fs(os, kcred, zplprops, tx);
#endif
dsl_dataset_rele(ds, FTAG);
@@ -285,6 +287,14 @@ dsl_pool_create(spa_t *spa, nvlist_t *zplprops, uint64_t txg)
return (dp);
}
+static int
+deadlist_enqueue_cb(void *arg, const blkptr_t *bp, dmu_tx_t *tx)
+{
+ dsl_deadlist_t *dl = arg;
+ dsl_deadlist_insert(dl, bp, tx);
+ return (0);
+}
+
void
dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
{
@@ -293,11 +303,19 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
dsl_dir_t *dd;
dsl_dataset_t *ds;
dsl_sync_task_group_t *dstg;
- objset_impl_t *mosi = dp->dp_meta_objset->os;
+ objset_t *mos = dp->dp_meta_objset;
hrtime_t start, write_time;
uint64_t data_written;
int err;
+ /*
+ * We need to copy dp_space_towrite() before doing
+ * dsl_sync_task_group_sync(), because
+ * dsl_dataset_snapshot_reserve_space() will increase
+ * dp_space_towrite but not actually write anything.
+ */
+ data_written = dp->dp_space_towrite[txg & TXG_MASK];
+
tx = dmu_tx_create_assigned(dp, txg);
dp->dp_read_overhead = 0;
@@ -323,11 +341,11 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
for (ds = list_head(&dp->dp_synced_datasets); ds;
ds = list_next(&dp->dp_synced_datasets, ds))
- dmu_objset_do_userquota_callbacks(ds->ds_user_ptr, tx);
+ dmu_objset_do_userquota_updates(ds->ds_objset, tx);
/*
* Sync the datasets again to push out the changes due to
- * userquota updates. This must be done before we process the
+ * userspace updates. This must be done before we process the
* sync tasks, because that could cause a snapshot of a dataset
* whose ds_bp will be rewritten when we do this 2nd sync.
*/
@@ -339,6 +357,16 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
}
err = zio_wait(zio);
+ /*
+ * Move dead blocks from the pending deadlist to the on-disk
+ * deadlist.
+ */
+ for (ds = list_head(&dp->dp_synced_datasets); ds;
+ ds = list_next(&dp->dp_synced_datasets, ds)) {
+ bplist_iterate(&ds->ds_pending_deadlist,
+ deadlist_enqueue_cb, &ds->ds_deadlist, tx);
+ }
+
while (dstg = txg_list_remove(&dp->dp_sync_tasks, txg)) {
/*
* No more sync tasks should have been added while we
@@ -354,14 +382,11 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
dsl_dir_sync(dd, tx);
write_time += gethrtime() - start;
- if (spa_sync_pass(dp->dp_spa) == 1)
- dsl_pool_scrub_sync(dp, tx);
-
start = gethrtime();
- if (list_head(&mosi->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||
- list_head(&mosi->os_free_dnodes[txg & TXG_MASK]) != NULL) {
+ if (list_head(&mos->os_dirty_dnodes[txg & TXG_MASK]) != NULL ||
+ list_head(&mos->os_free_dnodes[txg & TXG_MASK]) != NULL) {
zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
- dmu_objset_sync(mosi, zio, tx);
+ dmu_objset_sync(mos, zio, tx);
err = zio_wait(zio);
ASSERT(err == 0);
dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
@@ -374,7 +399,6 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
dmu_tx_commit(tx);
- data_written = dp->dp_space_towrite[txg & TXG_MASK];
dp->dp_space_towrite[txg & TXG_MASK] = 0;
ASSERT(dp->dp_tempreserved[txg & TXG_MASK] == 0);
@@ -399,10 +423,14 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
* amount of write traffic allowed into each transaction group.
* Weight the throughput calculation towards the current value:
* thru = 3/4 old_thru + 1/4 new_thru
+ *
+ * Note: write_time is in nanosecs, so write_time/MICROSEC
+ * yields millisecs
*/
ASSERT(zfs_write_limit_min > 0);
- if (data_written > zfs_write_limit_min / 8 && write_time > 0) {
- uint64_t throughput = (data_written * NANOSEC) / write_time;
+ if (data_written > zfs_write_limit_min / 8 && write_time > MICROSEC) {
+ uint64_t throughput = data_written / (write_time / MICROSEC);
+
if (dp->dp_throughput)
dp->dp_throughput = throughput / 4 +
3 * dp->dp_throughput / 4;
@@ -410,21 +438,24 @@ dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
dp->dp_throughput = throughput;
dp->dp_write_limit = MIN(zfs_write_limit_inflated,
MAX(zfs_write_limit_min,
- dp->dp_throughput * zfs_txg_synctime));
+ dp->dp_throughput * zfs_txg_synctime_ms));
}
}
void
-dsl_pool_zil_clean(dsl_pool_t *dp)
+dsl_pool_sync_done(dsl_pool_t *dp, uint64_t txg)
{
dsl_dataset_t *ds;
+ objset_t *os;
while (ds = list_head(&dp->dp_synced_datasets)) {
list_remove(&dp->dp_synced_datasets, ds);
- ASSERT(ds->ds_user_ptr != NULL);
- zil_clean(((objset_impl_t *)ds->ds_user_ptr)->os_zil);
+ os = ds->ds_objset;
+ zil_clean(os->os_zil);
+ ASSERT(!dmu_objset_is_dirty(os, txg));
dmu_buf_rele(ds->ds_dbuf, ds);
}
+ ASSERT(!dmu_objset_is_dirty(dp->dp_meta_objset, txg));
}
/*
@@ -601,6 +632,7 @@ upgrade_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
ASSERT(ds->ds_phys->ds_prev_snap_obj == prev->ds_object);
if (prev->ds_phys->ds_next_clones_obj == 0) {
+ dmu_buf_will_dirty(prev->ds_dbuf, tx);
prev->ds_phys->ds_next_clones_obj =
zap_create(dp->dp_meta_objset,
DMU_OT_NEXT_CLONES, DMU_OT_NONE, 0, tx);
@@ -620,8 +652,67 @@ dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx)
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(dp->dp_origin_snap != NULL);
- (void) dmu_objset_find_spa(dp->dp_spa, NULL, upgrade_clones_cb,
- tx, DS_FIND_CHILDREN);
+ VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL, upgrade_clones_cb,
+ tx, DS_FIND_CHILDREN));
+}
+
+/* ARGSUSED */
+static int
+upgrade_dir_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
+{
+ dmu_tx_t *tx = arg;
+ dsl_dataset_t *ds;
+ dsl_pool_t *dp = spa_get_dsl(spa);
+ objset_t *mos = dp->dp_meta_objset;
+
+ VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
+
+ if (ds->ds_dir->dd_phys->dd_origin_obj) {
+ dsl_dataset_t *origin;
+
+ VERIFY3U(0, ==, dsl_dataset_hold_obj(dp,
+ ds->ds_dir->dd_phys->dd_origin_obj, FTAG, &origin));
+
+ if (origin->ds_dir->dd_phys->dd_clones == 0) {
+ dmu_buf_will_dirty(origin->ds_dir->dd_dbuf, tx);
+ origin->ds_dir->dd_phys->dd_clones = zap_create(mos,
+ DMU_OT_DSL_CLONES, DMU_OT_NONE, 0, tx);
+ }
+
+ VERIFY3U(0, ==, zap_add_int(dp->dp_meta_objset,
+ origin->ds_dir->dd_phys->dd_clones, dsobj, tx));
+
+ dsl_dataset_rele(origin, FTAG);
+ }
+
+ dsl_dataset_rele(ds, FTAG);
+ return (0);
+}
+
+void
+dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx)
+{
+ ASSERT(dmu_tx_is_syncing(tx));
+ uint64_t obj;
+
+ (void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx);
+ VERIFY(0 == dsl_pool_open_special_dir(dp,
+ FREE_DIR_NAME, &dp->dp_free_dir));
+
+ /*
+ * We can't use bpobj_alloc(), because spa_version() still
+ * returns the old version, and we need a new-version bpobj with
+ * subobj support. So call dmu_object_alloc() directly.
+ */
+ obj = dmu_object_alloc(dp->dp_meta_objset, DMU_OT_BPOBJ,
+ SPA_MAXBLOCKSIZE, DMU_OT_BPOBJ_HDR, sizeof (bpobj_phys_t), tx);
+ VERIFY3U(0, ==, zap_add(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
+ DMU_POOL_FREE_BPOBJ, sizeof (uint64_t), 1, &obj, tx));
+ VERIFY3U(0, ==, bpobj_open(&dp->dp_free_bpobj,
+ dp->dp_meta_objset, obj));
+
+ VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL,
+ upgrade_dir_clones_cb, tx, DS_FIND_CHILDREN));
}
void
@@ -638,7 +729,7 @@ dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
dsobj = dsl_dataset_create_sync(dp->dp_root_dir, ORIGIN_DIR_NAME,
NULL, 0, kcred, tx);
VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
- dsl_dataset_snapshot_sync(ds, ORIGIN_DIR_NAME, kcred, tx);
+ dsl_dataset_snapshot_sync(ds, ORIGIN_DIR_NAME, tx);
VERIFY(0 == dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
dp, &dp->dp_origin_snap));
dsl_dataset_rele(ds, FTAG);
@@ -650,3 +741,108 @@ dsl_pool_vnrele_taskq(dsl_pool_t *dp)
{
return (dp->dp_vnrele_taskq);
}
+
+/*
+ * Walk through the pool-wide zap object of temporary snapshot user holds
+ * and release them.
+ */
+void
+dsl_pool_clean_tmp_userrefs(dsl_pool_t *dp)
+{
+ zap_attribute_t za;
+ zap_cursor_t zc;
+ objset_t *mos = dp->dp_meta_objset;
+ uint64_t zapobj = dp->dp_tmp_userrefs_obj;
+
+ if (zapobj == 0)
+ return;
+ ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
+
+ for (zap_cursor_init(&zc, mos, zapobj);
+ zap_cursor_retrieve(&zc, &za) == 0;
+ zap_cursor_advance(&zc)) {
+ char *htag;
+ uint64_t dsobj;
+
+ htag = strchr(za.za_name, '-');
+ *htag = '\0';
+ ++htag;
+ dsobj = strtonum(za.za_name, NULL);
+ (void) dsl_dataset_user_release_tmp(dp, dsobj, htag);
+ }
+ zap_cursor_fini(&zc);
+}
+
+/*
+ * Create the pool-wide zap object for storing temporary snapshot holds.
+ */
+void
+dsl_pool_user_hold_create_obj(dsl_pool_t *dp, dmu_tx_t *tx)
+{
+ objset_t *mos = dp->dp_meta_objset;
+
+ ASSERT(dp->dp_tmp_userrefs_obj == 0);
+ ASSERT(dmu_tx_is_syncing(tx));
+
+ dp->dp_tmp_userrefs_obj = zap_create(mos, DMU_OT_USERREFS,
+ DMU_OT_NONE, 0, tx);
+
+ VERIFY(zap_add(mos, DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_TMP_USERREFS,
+ sizeof (uint64_t), 1, &dp->dp_tmp_userrefs_obj, tx) == 0);
+}
+
+static int
+dsl_pool_user_hold_rele_impl(dsl_pool_t *dp, uint64_t dsobj,
+ const char *tag, uint64_t *now, dmu_tx_t *tx, boolean_t holding)
+{
+ objset_t *mos = dp->dp_meta_objset;
+ uint64_t zapobj = dp->dp_tmp_userrefs_obj;
+ char *name;
+ int error;
+
+ ASSERT(spa_version(dp->dp_spa) >= SPA_VERSION_USERREFS);
+ ASSERT(dmu_tx_is_syncing(tx));
+
+ /*
+ * If the pool was created prior to SPA_VERSION_USERREFS, the
+ * zap object for temporary holds might not exist yet.
+ */
+ if (zapobj == 0) {
+ if (holding) {
+ dsl_pool_user_hold_create_obj(dp, tx);
+ zapobj = dp->dp_tmp_userrefs_obj;
+ } else {
+ return (ENOENT);
+ }
+ }
+
+ name = kmem_asprintf("%llx-%s", (u_longlong_t)dsobj, tag);
+ if (holding)
+ error = zap_add(mos, zapobj, name, 8, 1, now, tx);
+ else
+ error = zap_remove(mos, zapobj, name, tx);
+ strfree(name);
+
+ return (error);
+}
+
+/*
+ * Add a temporary hold for the given dataset object and tag.
+ */
+int
+dsl_pool_user_hold(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
+ uint64_t *now, dmu_tx_t *tx)
+{
+ return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, now, tx, B_TRUE));
+}
+
+/*
+ * Release a temporary hold for the given dataset object and tag.
+ */
+int
+dsl_pool_user_release(dsl_pool_t *dp, uint64_t dsobj, const char *tag,
+ dmu_tx_t *tx)
+{
+ return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, NULL,
+ tx, B_FALSE));
+}