dsl_pool.c revision c33e334fd3eb2b3d91c4b9667d7a465b6924e8d3
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2009 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <sys/dsl_pool.h>
#include <sys/dsl_dataset.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_synctask.h>
#include <sys/dmu_tx.h>
#include <sys/dmu_objset.h>
#include <sys/arc.h>
#include <sys/zap.h>
#include <sys/zio.h>
#include <sys/zfs_context.h>
#include <sys/fs/zfs.h>
#include <sys/zfs_znode.h>
#include <sys/spa_impl.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 */
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 */
uint64_t zfs_write_limit_inflated = 0;
uint64_t zfs_write_limit_override = 0;
kmutex_t zfs_write_limit_lock;
static pgcnt_t old_physmem = 0;
static int
dsl_pool_open_special_dir(dsl_pool_t *dp, const char *name, dsl_dir_t **ddp)
{
uint64_t obj;
int err;
err = zap_lookup(dp->dp_meta_objset,
dp->dp_root_dir->dd_phys->dd_child_dir_zapobj,
name, sizeof (obj), 1, &obj);
if (err)
return (err);
return (dsl_dir_open_obj(dp, obj, name, dp, ddp));
}
static dsl_pool_t *
dsl_pool_open_impl(spa_t *spa, uint64_t txg)
{
dsl_pool_t *dp;
blkptr_t *bp = spa_get_rootblkptr(spa);
dp = kmem_zalloc(sizeof (dsl_pool_t), KM_SLEEP);
dp->dp_spa = spa;
dp->dp_meta_rootbp = *bp;
rw_init(&dp->dp_config_rwlock, NULL, RW_DEFAULT, NULL);
dp->dp_write_limit = zfs_write_limit_min;
txg_init(dp, txg);
txg_list_create(&dp->dp_dirty_datasets,
offsetof(dsl_dataset_t, ds_dirty_link));
txg_list_create(&dp->dp_dirty_dirs,
offsetof(dsl_dir_t, dd_dirty_link));
txg_list_create(&dp->dp_sync_tasks,
offsetof(dsl_sync_task_group_t, dstg_node));
list_create(&dp->dp_synced_datasets, sizeof (dsl_dataset_t),
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);
return (dp);
}
int
dsl_pool_open(spa_t *spa, uint64_t txg, dsl_pool_t **dpp)
{
int err;
dsl_pool_t *dp = dsl_pool_open_impl(spa, txg);
dsl_dir_t *dd;
dsl_dataset_t *ds;
rw_enter(&dp->dp_config_rwlock, RW_WRITER);
err = dmu_objset_open_impl(spa, NULL, &dp->dp_meta_rootbp,
&dp->dp_meta_objset);
if (err)
goto out;
err = zap_lookup(dp->dp_meta_objset, DMU_POOL_DIRECTORY_OBJECT,
DMU_POOL_ROOT_DATASET, sizeof (uint64_t), 1,
&dp->dp_root_dir_obj);
if (err)
goto out;
err = dsl_dir_open_obj(dp, dp->dp_root_dir_obj,
NULL, dp, &dp->dp_root_dir);
if (err)
goto out;
err = dsl_pool_open_special_dir(dp, MOS_DIR_NAME, &dp->dp_mos_dir);
if (err)
goto out;
if (spa_version(spa) >= SPA_VERSION_ORIGIN) {
err = dsl_pool_open_special_dir(dp, ORIGIN_DIR_NAME, &dd);
if (err)
goto out;
err = dsl_dataset_hold_obj(dp, dd->dd_phys->dd_head_dataset_obj,
FTAG, &ds);
if (err == 0) {
err = dsl_dataset_hold_obj(dp,
ds->ds_phys->ds_prev_snap_obj, dp,
&dp->dp_origin_snap);
dsl_dataset_rele(ds, FTAG);
}
dsl_dir_close(dd, dp);
if (err)
goto out;
}
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;
/* 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 (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);
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;
}
out:
rw_exit(&dp->dp_config_rwlock);
if (err)
dsl_pool_close(dp);
else
*dpp = dp;
return (err);
}
void
dsl_pool_close(dsl_pool_t *dp)
{
/* drop our references from dsl_pool_open() */
/*
* Since we held the origin_snap from "syncing" context (which
* includes pool-opening context), it actually only got a "ref"
* and not a hold, so just drop that here.
*/
if (dp->dp_origin_snap)
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_root_dir)
dsl_dir_close(dp->dp_root_dir, dp);
/* undo the dmu_objset_open_impl(mos) from dsl_pool_open() */
if (dp->dp_meta_objset)
dmu_objset_evict(dp->dp_meta_objset);
txg_list_destroy(&dp->dp_dirty_datasets);
txg_list_destroy(&dp->dp_dirty_dirs);
list_destroy(&dp->dp_synced_datasets);
arc_flush(dp->dp_spa);
txg_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));
kmem_free(dp, sizeof (dsl_pool_t));
}
dsl_pool_t *
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_t *os;
dsl_dataset_t *ds;
uint64_t dsobj;
/* 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);
/* 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);
/* 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,
NULL, dp, &dp->dp_root_dir));
/* create and open the meta-objset dir */
(void) dsl_dir_create_sync(dp, dp->dp_root_dir, MOS_DIR_NAME, tx);
VERIFY(0 == dsl_pool_open_special_dir(dp,
MOS_DIR_NAME, &dp->dp_mos_dir));
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);
/* create the root objset */
VERIFY(0 == dsl_dataset_hold_obj(dp, dsobj, 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(os, kcred, zplprops, tx);
#endif
dsl_dataset_rele(ds, FTAG);
dmu_tx_commit(tx);
return (dp);
}
void
dsl_pool_sync(dsl_pool_t *dp, uint64_t txg)
{
zio_t *zio;
dmu_tx_t *tx;
dsl_dir_t *dd;
dsl_dataset_t *ds;
dsl_sync_task_group_t *dstg;
objset_t *mos = dp->dp_meta_objset;
hrtime_t start, write_time;
uint64_t data_written;
int err;
tx = dmu_tx_create_assigned(dp, txg);
dp->dp_read_overhead = 0;
start = gethrtime();
zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {
/*
* We must not sync any non-MOS datasets twice, because
* we may have taken a snapshot of them. However, we
* may sync newly-created datasets on pass 2.
*/
ASSERT(!list_link_active(&ds->ds_synced_link));
list_insert_tail(&dp->dp_synced_datasets, ds);
dsl_dataset_sync(ds, zio, tx);
}
DTRACE_PROBE(pool_sync__1setup);
err = zio_wait(zio);
write_time = gethrtime() - start;
ASSERT(err == 0);
DTRACE_PROBE(pool_sync__2rootzio);
for (ds = list_head(&dp->dp_synced_datasets); ds;
ds = list_next(&dp->dp_synced_datasets, ds))
dmu_objset_do_userquota_callbacks(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
* sync tasks, because that could cause a snapshot of a dataset
* whose ds_bp will be rewritten when we do this 2nd sync.
*/
zio = zio_root(dp->dp_spa, NULL, NULL, ZIO_FLAG_MUSTSUCCEED);
while (ds = txg_list_remove(&dp->dp_dirty_datasets, txg)) {
ASSERT(list_link_active(&ds->ds_synced_link));
dmu_buf_rele(ds->ds_dbuf, ds);
dsl_dataset_sync(ds, zio, tx);
}
err = zio_wait(zio);
while (dstg = txg_list_remove(&dp->dp_sync_tasks, txg)) {
/*
* No more sync tasks should have been added while we
* were syncing.
*/
ASSERT(spa_sync_pass(dp->dp_spa) == 1);
dsl_sync_task_group_sync(dstg, tx);
}
DTRACE_PROBE(pool_sync__3task);
start = gethrtime();
while (dd = txg_list_remove(&dp->dp_dirty_dirs, 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(&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(mos, zio, tx);
err = zio_wait(zio);
ASSERT(err == 0);
dprintf_bp(&dp->dp_meta_rootbp, "meta objset rootbp is %s", "");
spa_set_rootblkptr(dp->dp_spa, &dp->dp_meta_rootbp);
}
write_time += gethrtime() - start;
DTRACE_PROBE2(pool_sync__4io, hrtime_t, write_time,
hrtime_t, dp->dp_read_overhead);
write_time -= dp->dp_read_overhead;
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);
/*
* If the write limit max has not been explicitly set, set it
* to a fraction of available physical memory (default 1/8th).
* Note that we must inflate the limit because the spa
* inflates write sizes to account for data replication.
* Check this each sync phase to catch changing memory size.
*/
if (physmem != old_physmem && zfs_write_limit_shift) {
mutex_enter(&zfs_write_limit_lock);
old_physmem = physmem;
zfs_write_limit_max = ptob(physmem) >> zfs_write_limit_shift;
zfs_write_limit_inflated = MAX(zfs_write_limit_min,
spa_get_asize(dp->dp_spa, zfs_write_limit_max));
mutex_exit(&zfs_write_limit_lock);
}
/*
* Attempt to keep the sync time consistent by adjusting the
* 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
*/
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 (dp->dp_throughput)
dp->dp_throughput = throughput / 4 +
3 * dp->dp_throughput / 4;
else
dp->dp_throughput = throughput;
dp->dp_write_limit = MIN(zfs_write_limit_inflated,
MAX(zfs_write_limit_min,
dp->dp_throughput * zfs_txg_synctime));
}
}
void
dsl_pool_zil_clean(dsl_pool_t *dp)
{
dsl_dataset_t *ds;
while (ds = list_head(&dp->dp_synced_datasets)) {
list_remove(&dp->dp_synced_datasets, ds);
ASSERT(ds->ds_objset != NULL);
zil_clean(ds->ds_objset->os_zil);
dmu_buf_rele(ds->ds_dbuf, ds);
}
}
/*
* TRUE if the current thread is the tx_sync_thread or if we
* are being called from SPA context during pool initialization.
*/
int
dsl_pool_sync_context(dsl_pool_t *dp)
{
return (curthread == dp->dp_tx.tx_sync_thread ||
spa_get_dsl(dp->dp_spa) == NULL);
}
uint64_t
dsl_pool_adjustedsize(dsl_pool_t *dp, boolean_t netfree)
{
uint64_t space, resv;
/*
* Reserve about 1.6% (1/64), or at least 32MB, for allocation
* efficiency.
* XXX The intent log is not accounted for, so it must fit
* within this slop.
*
* If we're trying to assess whether it's OK to do a free,
* cut the reservation in half to allow forward progress
* (e.g. make it possible to rm(1) files from a full pool).
*/
space = spa_get_dspace(dp->dp_spa);
resv = MAX(space >> 6, SPA_MINDEVSIZE >> 1);
if (netfree)
resv >>= 1;
return (space - resv);
}
int
dsl_pool_tempreserve_space(dsl_pool_t *dp, uint64_t space, dmu_tx_t *tx)
{
uint64_t reserved = 0;
uint64_t write_limit = (zfs_write_limit_override ?
zfs_write_limit_override : dp->dp_write_limit);
if (zfs_no_write_throttle) {
atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK],
space);
return (0);
}
/*
* Check to see if we have exceeded the maximum allowed IO for
* this transaction group. We can do this without locks since
* a little slop here is ok. Note that we do the reserved check
* with only half the requested reserve: this is because the
* reserve requests are worst-case, and we really don't want to
* throttle based off of worst-case estimates.
*/
if (write_limit > 0) {
reserved = dp->dp_space_towrite[tx->tx_txg & TXG_MASK]
+ dp->dp_tempreserved[tx->tx_txg & TXG_MASK] / 2;
if (reserved && reserved > write_limit)
return (ERESTART);
}
atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], space);
/*
* If this transaction group is over 7/8ths capacity, delay
* the caller 1 clock tick. This will slow down the "fill"
* rate until the sync process can catch up with us.
*/
if (reserved && reserved > (write_limit - (write_limit >> 3)))
txg_delay(dp, tx->tx_txg, 1);
return (0);
}
void
dsl_pool_tempreserve_clear(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
{
ASSERT(dp->dp_tempreserved[tx->tx_txg & TXG_MASK] >= space);
atomic_add_64(&dp->dp_tempreserved[tx->tx_txg & TXG_MASK], -space);
}
void
dsl_pool_memory_pressure(dsl_pool_t *dp)
{
uint64_t space_inuse = 0;
int i;
if (dp->dp_write_limit == zfs_write_limit_min)
return;
for (i = 0; i < TXG_SIZE; i++) {
space_inuse += dp->dp_space_towrite[i];
space_inuse += dp->dp_tempreserved[i];
}
dp->dp_write_limit = MAX(zfs_write_limit_min,
MIN(dp->dp_write_limit, space_inuse / 4));
}
void
dsl_pool_willuse_space(dsl_pool_t *dp, int64_t space, dmu_tx_t *tx)
{
if (space > 0) {
mutex_enter(&dp->dp_lock);
dp->dp_space_towrite[tx->tx_txg & TXG_MASK] += space;
mutex_exit(&dp->dp_lock);
}
}
/* ARGSUSED */
static int
upgrade_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
{
dmu_tx_t *tx = arg;
dsl_dataset_t *ds, *prev = NULL;
int err;
dsl_pool_t *dp = spa_get_dsl(spa);
err = dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds);
if (err)
return (err);
while (ds->ds_phys->ds_prev_snap_obj != 0) {
err = dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
FTAG, &prev);
if (err) {
dsl_dataset_rele(ds, FTAG);
return (err);
}
if (prev->ds_phys->ds_next_snap_obj != ds->ds_object)
break;
dsl_dataset_rele(ds, FTAG);
ds = prev;
prev = NULL;
}
if (prev == NULL) {
prev = dp->dp_origin_snap;
/*
* The $ORIGIN can't have any data, or the accounting
* will be wrong.
*/
ASSERT(prev->ds_phys->ds_bp.blk_birth == 0);
/* The origin doesn't get attached to itself */
if (ds->ds_object == prev->ds_object) {
dsl_dataset_rele(ds, FTAG);
return (0);
}
dmu_buf_will_dirty(ds->ds_dbuf, tx);
ds->ds_phys->ds_prev_snap_obj = prev->ds_object;
ds->ds_phys->ds_prev_snap_txg = prev->ds_phys->ds_creation_txg;
dmu_buf_will_dirty(ds->ds_dir->dd_dbuf, tx);
ds->ds_dir->dd_phys->dd_origin_obj = prev->ds_object;
dmu_buf_will_dirty(prev->ds_dbuf, tx);
prev->ds_phys->ds_num_children++;
if (ds->ds_phys->ds_next_snap_obj == 0) {
ASSERT(ds->ds_prev == NULL);
VERIFY(0 == dsl_dataset_hold_obj(dp,
ds->ds_phys->ds_prev_snap_obj, ds, &ds->ds_prev));
}
}
ASSERT(ds->ds_dir->dd_phys->dd_origin_obj == prev->ds_object);
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);
}
VERIFY(0 == zap_add_int(dp->dp_meta_objset,
prev->ds_phys->ds_next_clones_obj, ds->ds_object, tx));
dsl_dataset_rele(ds, FTAG);
if (prev != dp->dp_origin_snap)
dsl_dataset_rele(prev, FTAG);
return (0);
}
void
dsl_pool_upgrade_clones(dsl_pool_t *dp, dmu_tx_t *tx)
{
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(dp->dp_origin_snap != NULL);
VERIFY3U(0, ==, dmu_objset_find_spa(dp->dp_spa, NULL, upgrade_clones_cb,
tx, DS_FIND_CHILDREN));
}
void
dsl_pool_create_origin(dsl_pool_t *dp, dmu_tx_t *tx)
{
uint64_t dsobj;
dsl_dataset_t *ds;
ASSERT(dmu_tx_is_syncing(tx));
ASSERT(dp->dp_origin_snap == NULL);
/* create the origin dir, ds, & snap-ds */
rw_enter(&dp->dp_config_rwlock, RW_WRITER);
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);
VERIFY(0 == dsl_dataset_hold_obj(dp, ds->ds_phys->ds_prev_snap_obj,
dp, &dp->dp_origin_snap));
dsl_dataset_rele(ds, FTAG);
rw_exit(&dp->dp_config_rwlock);
}
taskq_t *
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, time_t *t, 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, t, 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,
time_t *t, dmu_tx_t *tx)
{
return (dsl_pool_user_hold_rele_impl(dp, dsobj, tag, t, 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));
}