4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2012 by Delphix. All rights reserved.
27 #include <sys/dmu_tx.h>
28 #include <sys/dsl_pool.h>
29 #include <sys/dsl_dir.h>
30 #include <sys/dsl_synctask.h>
31 #include <sys/metaslab.h>
33 #define DST_AVG_BLKSHIFT 14
37 dsl_null_checkfunc(void *arg, dmu_tx_t *tx)
43 * Called from open context to perform a callback in syncing context. Waits
44 * for the operation to complete.
46 * The checkfunc will be called from open context as a preliminary check
47 * which can quickly fail. If it succeeds, it will be called again from
48 * syncing context. The checkfunc should generally be designed to work
49 * properly in either context, but if necessary it can check
50 * dmu_tx_is_syncing(tx).
52 * The synctask infrastructure enforces proper locking strategy with respect
53 * to the dp_config_rwlock -- the lock will always be held when the callbacks
54 * are called. It will be held for read during the open-context (preliminary)
55 * call to the checkfunc, and then held for write from syncing context during
56 * the calls to the check and sync funcs.
58 * A dataset or pool name can be passed as the first argument. Typically,
59 * the check func will hold, check the return value of the hold, and then
60 * release the dataset. The sync func will VERIFYO(hold()) the dataset.
61 * This is safe because no changes can be made between the check and sync funcs,
62 * and the sync func will only be called if the check func successfully opened
66 dsl_sync_task(const char *pool, dsl_checkfunc_t *checkfunc,
67 dsl_syncfunc_t *syncfunc, void *arg, int blocks_modified)
72 dsl_sync_task_t dst = { { { NULL } } };
75 err = spa_open(pool, &spa, FTAG);
78 dp = spa_get_dsl(spa);
81 tx = dmu_tx_create_dd(dp->dp_mos_dir);
82 VERIFY0(dmu_tx_assign(tx, TXG_WAIT));
85 dst.dst_txg = dmu_tx_get_txg(tx);
86 dst.dst_space = blocks_modified << DST_AVG_BLKSHIFT;
87 dst.dst_checkfunc = checkfunc != NULL ? checkfunc : dsl_null_checkfunc;
88 dst.dst_syncfunc = syncfunc;
91 dst.dst_nowaiter = B_FALSE;
93 dsl_pool_config_enter(dp, FTAG);
94 err = dst.dst_checkfunc(arg, tx);
95 dsl_pool_config_exit(dp, FTAG);
103 VERIFY(txg_list_add_tail(&dp->dp_sync_tasks, &dst, dst.dst_txg));
107 txg_wait_synced(dp, dst.dst_txg);
109 if (dst.dst_error == EAGAIN) {
110 txg_wait_synced(dp, dst.dst_txg + TXG_DEFER_SIZE);
114 spa_close(spa, FTAG);
115 return (dst.dst_error);
119 dsl_sync_task_nowait(dsl_pool_t *dp, dsl_syncfunc_t *syncfunc, void *arg,
120 int blocks_modified, dmu_tx_t *tx)
122 dsl_sync_task_t *dst = kmem_zalloc(sizeof (*dst), KM_SLEEP);
125 dst->dst_txg = dmu_tx_get_txg(tx);
126 dst->dst_space = blocks_modified << DST_AVG_BLKSHIFT;
127 dst->dst_checkfunc = dsl_null_checkfunc;
128 dst->dst_syncfunc = syncfunc;
131 dst->dst_nowaiter = B_TRUE;
133 VERIFY(txg_list_add_tail(&dp->dp_sync_tasks, dst, dst->dst_txg));
137 * Called in syncing context to execute the synctask.
140 dsl_sync_task_sync(dsl_sync_task_t *dst, dmu_tx_t *tx)
142 dsl_pool_t *dp = dst->dst_pool;
143 uint64_t quota, used;
145 ASSERT0(dst->dst_error);
148 * Check for sufficient space. We just check against what's
149 * on-disk; we don't want any in-flight accounting to get in our
150 * way, because open context may have already used up various
151 * in-core limits (arc_tempreserve, dsl_pool_tempreserve).
153 quota = dsl_pool_adjustedsize(dp, B_FALSE) -
154 metaslab_class_get_deferred(spa_normal_class(dp->dp_spa));
155 used = dp->dp_root_dir->dd_phys->dd_used_bytes;
156 /* MOS space is triple-dittoed, so we multiply by 3. */
157 if (dst->dst_space > 0 && used + dst->dst_space * 3 > quota) {
158 dst->dst_error = ENOSPC;
159 if (dst->dst_nowaiter)
160 kmem_free(dst, sizeof (*dst));
165 * Check for errors by calling checkfunc.
167 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG);
168 dst->dst_error = dst->dst_checkfunc(dst->dst_arg, tx);
169 if (dst->dst_error == 0)
170 dst->dst_syncfunc(dst->dst_arg, tx);
171 rrw_exit(&dp->dp_config_rwlock, FTAG);
172 if (dst->dst_nowaiter)
173 kmem_free(dst, sizeof (*dst));
176 #if defined(_KERNEL) && defined(HAVE_SPL)