diff options
Diffstat (limited to 'sys/contrib/openzfs/module/zfs/dsl_synctask.c')
-rw-r--r-- | sys/contrib/openzfs/module/zfs/dsl_synctask.c | 261 |
1 files changed, 261 insertions, 0 deletions
diff --git a/sys/contrib/openzfs/module/zfs/dsl_synctask.c b/sys/contrib/openzfs/module/zfs/dsl_synctask.c new file mode 100644 index 000000000000..2d6ca8549eb9 --- /dev/null +++ b/sys/contrib/openzfs/module/zfs/dsl_synctask.c @@ -0,0 +1,261 @@ +/* + * 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, dsl_sigfunc_t *sigfunc, 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); + + if (sigfunc != NULL && txg_wait_synced_sig(dp, dst.dst_txg)) { + /* current contract is to call func once */ + sigfunc(arg, tx); + sigfunc = NULL; /* in case we're performing an EAGAIN retry */ + } + 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, NULL, 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 precondition/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, NULL, arg, + blocks_modified, space_check, B_TRUE)); +} + +/* + * A standard synctask that can be interrupted from a signal. The sigfunc + * is called once if a signal occurred while waiting for the task to sync. + */ +int +dsl_sync_task_sig(const char *pool, dsl_checkfunc_t *checkfunc, + dsl_syncfunc_t *syncfunc, dsl_sigfunc_t *sigfunc, void *arg, + int blocks_modified, zfs_space_check_t space_check) +{ + return (dsl_sync_task_common(pool, checkfunc, syncfunc, sigfunc, arg, + blocks_modified, space_check, B_FALSE)); +} + +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 |