dsl_synctask.c revision 277585
1/* 2 * CDDL HEADER START 3 * 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. 7 * 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. 12 * 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] 18 * 19 * CDDL HEADER END 20 */ 21/* 22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2012, 2014 by Delphix. All rights reserved. 24 */ 25 26#include <sys/dmu.h> 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> 32 33#define DST_AVG_BLKSHIFT 14 34 35/* ARGSUSED */ 36static int 37dsl_null_checkfunc(void *arg, dmu_tx_t *tx) 38{ 39 return (0); 40} 41 42/* 43 * Called from open context to perform a callback in syncing context. Waits 44 * for the operation to complete. 45 * 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). 51 * 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. 57 * 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 63 * the dataset. 64 */ 65int 66dsl_sync_task(const char *pool, dsl_checkfunc_t *checkfunc, 67 dsl_syncfunc_t *syncfunc, void *arg, 68 int blocks_modified, zfs_space_check_t space_check) 69{ 70 spa_t *spa; 71 dmu_tx_t *tx; 72 int err; 73 dsl_sync_task_t dst = { 0 }; 74 dsl_pool_t *dp; 75 76 err = spa_open(pool, &spa, FTAG); 77 if (err != 0) 78 return (err); 79 dp = spa_get_dsl(spa); 80 81top: 82 tx = dmu_tx_create_dd(dp->dp_mos_dir); 83 VERIFY0(dmu_tx_assign(tx, TXG_WAIT)); 84 85 dst.dst_pool = dp; 86 dst.dst_txg = dmu_tx_get_txg(tx); 87 dst.dst_space = blocks_modified << DST_AVG_BLKSHIFT; 88 dst.dst_space_check = space_check; 89 dst.dst_checkfunc = checkfunc != NULL ? checkfunc : dsl_null_checkfunc; 90 dst.dst_syncfunc = syncfunc; 91 dst.dst_arg = arg; 92 dst.dst_error = 0; 93 dst.dst_nowaiter = B_FALSE; 94 95 dsl_pool_config_enter(dp, FTAG); 96 err = dst.dst_checkfunc(arg, tx); 97 dsl_pool_config_exit(dp, FTAG); 98 99 if (err != 0) { 100 dmu_tx_commit(tx); 101 spa_close(spa, FTAG); 102 return (err); 103 } 104 105 VERIFY(txg_list_add_tail(&dp->dp_sync_tasks, &dst, dst.dst_txg)); 106 107 dmu_tx_commit(tx); 108 109 txg_wait_synced(dp, dst.dst_txg); 110 111 if (dst.dst_error == EAGAIN) { 112 txg_wait_synced(dp, dst.dst_txg + TXG_DEFER_SIZE); 113 goto top; 114 } 115 116 spa_close(spa, FTAG); 117 return (dst.dst_error); 118} 119 120void 121dsl_sync_task_nowait(dsl_pool_t *dp, dsl_syncfunc_t *syncfunc, void *arg, 122 int blocks_modified, zfs_space_check_t space_check, dmu_tx_t *tx) 123{ 124 dsl_sync_task_t *dst = kmem_zalloc(sizeof (*dst), KM_SLEEP); 125 126 dst->dst_pool = dp; 127 dst->dst_txg = dmu_tx_get_txg(tx); 128 dst->dst_space = blocks_modified << DST_AVG_BLKSHIFT; 129 dst->dst_space_check = space_check; 130 dst->dst_checkfunc = dsl_null_checkfunc; 131 dst->dst_syncfunc = syncfunc; 132 dst->dst_arg = arg; 133 dst->dst_error = 0; 134 dst->dst_nowaiter = B_TRUE; 135 136 VERIFY(txg_list_add_tail(&dp->dp_sync_tasks, dst, dst->dst_txg)); 137} 138 139/* 140 * Called in syncing context to execute the synctask. 141 */ 142void 143dsl_sync_task_sync(dsl_sync_task_t *dst, dmu_tx_t *tx) 144{ 145 dsl_pool_t *dp = dst->dst_pool; 146 147 ASSERT0(dst->dst_error); 148 149 /* 150 * Check for sufficient space. 151 * 152 * When the sync task was created, the caller specified the 153 * type of space checking required. See the comment in 154 * zfs_space_check_t for details on the semantics of each 155 * type of space checking. 156 * 157 * We just check against what's on-disk; we don't want any 158 * in-flight accounting to get in our way, because open context 159 * may have already used up various in-core limits 160 * (arc_tempreserve, dsl_pool_tempreserve). 161 */ 162 if (dst->dst_space_check != ZFS_SPACE_CHECK_NONE) { 163 uint64_t quota = dsl_pool_adjustedsize(dp, 164 dst->dst_space_check == ZFS_SPACE_CHECK_RESERVED) - 165 metaslab_class_get_deferred(spa_normal_class(dp->dp_spa)); 166 uint64_t used = dsl_dir_phys(dp->dp_root_dir)->dd_used_bytes; 167 /* MOS space is triple-dittoed, so we multiply by 3. */ 168 if (dst->dst_space > 0 && used + dst->dst_space * 3 > quota) { 169 dst->dst_error = SET_ERROR(ENOSPC); 170 if (dst->dst_nowaiter) 171 kmem_free(dst, sizeof (*dst)); 172 return; 173 } 174 } 175 176 /* 177 * Check for errors by calling checkfunc. 178 */ 179 rrw_enter(&dp->dp_config_rwlock, RW_WRITER, FTAG); 180 dst->dst_error = dst->dst_checkfunc(dst->dst_arg, tx); 181 if (dst->dst_error == 0) 182 dst->dst_syncfunc(dst->dst_arg, tx); 183 rrw_exit(&dp->dp_config_rwlock, FTAG); 184 if (dst->dst_nowaiter) 185 kmem_free(dst, sizeof (*dst)); 186} 187