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/*
* 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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2017 by Delphix. All rights reserved.
*/
#include <sys/dmu.h>
#include <sys/dmu_tx.h>
#include <sys/dsl_pool.h>
#include <sys/dsl_dir.h>
#include <sys/dsl_synctask.h>
#include <sys/metaslab.h>
#define DST_AVG_BLKSHIFT 14
/* ARGSUSED */
static int
dsl_null_checkfunc(void *arg, dmu_tx_t *tx)
{
return (0);
}
static int
dsl_sync_task_common(const char *pool, dsl_checkfunc_t *checkfunc,
dsl_syncfunc_t *syncfunc, void *arg,
int blocks_modified, zfs_space_check_t space_check, boolean_t early)
{
spa_t *spa;
dmu_tx_t *tx;
int err;
dsl_sync_task_t dst = { { { NULL } } };
dsl_pool_t *dp;
err = spa_open(pool, &spa, FTAG);
if (err != 0)
return (err);
dp = spa_get_dsl(spa);
top:
tx = dmu_tx_create_dd(dp->dp_mos_dir);
VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
dst.dst_pool = dp;
dst.dst_txg = dmu_tx_get_txg(tx);
dst.dst_space = blocks_modified << DST_AVG_BLKSHIFT;
dst.dst_space_check = space_check;
dst.dst_checkfunc = checkfunc != NULL ? checkfunc : dsl_null_checkfunc;
dst.dst_syncfunc = syncfunc;
dst.dst_arg = arg;
dst.dst_error = 0;
dst.dst_nowaiter = B_FALSE;
dsl_pool_config_enter(dp, FTAG);
err = dst.dst_checkfunc(arg, tx);
dsl_pool_config_exit(dp, FTAG);
if (err != 0) {
dmu_tx_commit(tx);
spa_close(spa, FTAG);
return (err);
}
txg_list_t *task_list = (early) ?
&dp->dp_early_sync_tasks : &dp->dp_sync_tasks;
VERIFY(txg_list_add_tail(task_list, &dst, dst.dst_txg));
dmu_tx_commit(tx);
txg_wait_synced(dp, dst.dst_txg);
if (dst.dst_error == EAGAIN) {
txg_wait_synced(dp, dst.dst_txg + TXG_DEFER_SIZE);
goto top;
}
spa_close(spa, FTAG);
return (dst.dst_error);
}
/*
* Called from open context to perform a callback in syncing context. Waits
* for the operation to complete.
*
* The checkfunc will be called from open context as a preliminary check
* which can quickly fail. If it succeeds, it will be called again from
* syncing context. The checkfunc should generally be designed to work
* properly in either context, but if necessary it can check
* dmu_tx_is_syncing(tx).
*
* The synctask infrastructure enforces proper locking strategy with respect
* to the dp_config_rwlock -- the lock will always be held when the callbacks
* are called. It will be held for read during the open-context (preliminary)
* call to the checkfunc, and then held for write from syncing context during
* the calls to the check and sync funcs.
*
* A dataset or pool name can be passed as the first argument. Typically,
* the check func will hold, check the return value of the hold, and then
* release the dataset. The sync func will VERIFYO(hold()) the dataset.
* This is safe because no changes can be made between the check and sync funcs,
* and the sync func will only be called if the check func successfully opened
* the dataset.
*/
int
dsl_sync_task(const char *pool, dsl_checkfunc_t *checkfunc,
dsl_syncfunc_t *syncfunc, void *arg,
int blocks_modified, zfs_space_check_t space_check)
{
return (dsl_sync_task_common(pool, checkfunc, syncfunc, arg,
blocks_modified, space_check, B_FALSE));
}
/*
* An early synctask works exactly as a standard synctask with one important
* difference on the way it is handled during syncing context. Standard
* synctasks run after we've written out all the dirty blocks of dirty
* datasets. Early synctasks are executed before writing out any dirty data,
* and thus before standard synctasks.
*
* For that reason, early synctasks can affect the process of writing dirty
* changes to disk for the txg that they run and should be used with caution.
* In addition, early synctasks should not dirty any metaslabs as this would
* invalidate the precodition/invariant for subsequent early synctasks.
* [see dsl_pool_sync() and dsl_early_sync_task_verify()]
*/
int
dsl_early_sync_task(const char *pool, dsl_checkfunc_t *checkfunc,
dsl_syncfunc_t *syncfunc, void *arg,
int blocks_modified, zfs_space_check_t space_check)
{
return (dsl_sync_task_common(pool, checkfunc, syncfunc, arg,
blocks_modified, space_check, B_TRUE));
}
static void
dsl_sync_task_nowait_common(dsl_pool_t *dp, dsl_syncfunc_t *syncfunc, void *arg,
int blocks_modified, zfs_space_check_t space_check, dmu_tx_t *tx,
boolean_t early)
{
dsl_sync_task_t *dst = kmem_zalloc(sizeof (*dst), KM_SLEEP);
dst->dst_pool = dp;
dst->dst_txg = dmu_tx_get_txg(tx);
dst->dst_space = blocks_modified << DST_AVG_BLKSHIFT;
dst->dst_space_check = space_check;
dst->dst_checkfunc = dsl_null_checkfunc;
dst->dst_syncfunc = syncfunc;
dst->dst_arg = arg;
dst->dst_error = 0;
dst->dst_nowaiter = B_TRUE;
txg_list_t *task_list = (early) ?
&dp->dp_early_sync_tasks : &dp->dp_sync_tasks;
VERIFY(txg_list_add_tail(task_list, dst, dst->dst_txg));
}
void
dsl_sync_task_nowait(dsl_pool_t *dp, dsl_syncfunc_t *syncfunc, void *arg,
int blocks_modified, zfs_space_check_t space_check, dmu_tx_t *tx)
{
dsl_sync_task_nowait_common(dp, syncfunc, arg,
blocks_modified, space_check, tx, B_FALSE);
}
void
dsl_early_sync_task_nowait(dsl_pool_t *dp, dsl_syncfunc_t *syncfunc, void *arg,
int blocks_modified, zfs_space_check_t space_check, dmu_tx_t *tx)
{
dsl_sync_task_nowait_common(dp, syncfunc, arg,
blocks_modified, space_check, tx, B_TRUE);
}
/*
* Called in syncing context to execute the synctask.
*/
void
dsl_sync_task_sync(dsl_sync_task_t *dst, dmu_tx_t *tx)
{
dsl_pool_t *dp = dst->dst_pool;
ASSERT0(dst->dst_error);
/*
* Check for sufficient space.
*
* When the sync task was created, the caller specified the
* type of space checking required. See the comment in
* zfs_space_check_t for details on the semantics of each
* type of space checking.
*
* We just check against what's on-disk; we don't want any
* in-flight accounting to get in our way, because open context
* may have already used up various in-core limits
* (arc_tempreserve, dsl_pool_tempreserve).
*/
if (dst->dst_space_check != ZFS_SPACE_CHECK_NONE) {
uint64_t quota = dsl_pool_unreserved_space(dp,
dst->dst_space_check);
uint64_t used = dsl_dir_phys(dp->dp_root_dir)->dd_used_bytes;
/* MOS space is triple-dittoed, so we multiply by 3. */
if (used + dst->dst_space * 3 > quota) {
dst->dst_error = SET_ERROR(ENOSPC);
if (dst->dst_nowaiter)
kmem_free(dst, sizeof (*dst));
return;
}
}
/*
* Check for errors by calling checkfunc.
*/
rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
dst->dst_error = dst->dst_checkfunc(dst->dst_arg, tx);
if (dst->dst_error == 0)
dst->dst_syncfunc(dst->dst_arg, tx);
rrw_exit(&dp->dp_config_rwlock, FTAG);
if (dst->dst_nowaiter)
kmem_free(dst, sizeof (*dst));
}
#if defined(_KERNEL)
EXPORT_SYMBOL(dsl_sync_task);
EXPORT_SYMBOL(dsl_sync_task_nowait);
#endif
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