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 2009 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* 27 * Copyright (c) 2013 by Delphix. All rights reserved. 28 */ 29 30 #ifndef _ZIO_IMPL_H 31 #define _ZIO_IMPL_H 32 33 #include <sys/zfs_context.h> 34 #include <sys/zio.h> 35 36 #ifdef __cplusplus 37 extern "C" { 38 #endif 39 40 /* 41 * XXX -- Describe ZFS I/O pipeline here. Fill in as needed. 42 * 43 * The ZFS I/O pipeline is comprised of various stages which are defined 44 * in the zio_stage enum below. The individual stages are used to construct 45 * these basic I/O operations: Read, Write, Free, Claim, and Ioctl. 46 * 47 * I/O operations: (XXX - provide detail for each of the operations) 48 * 49 * Read: 50 * Write: 51 * Free: 52 * Claim: 53 * Ioctl: 54 * 55 * Although the most common pipeline are used by the basic I/O operations 56 * above, there are some helper pipelines (one could consider them 57 * sub-pipelines) which are used internally by the ZIO module and are 58 * explained below: 59 * 60 * Interlock Pipeline: 61 * The interlock pipeline is the most basic pipeline and is used by all 62 * of the I/O operations. The interlock pipeline does not perform any I/O 63 * and is used to coordinate the dependencies between I/Os that are being 64 * issued (i.e. the parent/child relationship). 65 * 66 * Vdev child Pipeline: 67 * The vdev child pipeline is responsible for performing the physical I/O. 68 * It is in this pipeline where the I/O are queued and possibly cached. 69 * 70 * In addition to performing I/O, the pipeline is also responsible for 71 * data transformations. The transformations performed are based on the 72 * specific properties that user may have selected and modify the 73 * behavior of the pipeline. Examples of supported transformations are 74 * compression, dedup, and nop writes. Transformations will either modify 75 * the data or the pipeline. This list below further describes each of 76 * the supported transformations: 77 * 78 * Compression: 79 * ZFS supports three different flavors of compression -- gzip, lzjb, and 80 * zle. Compression occurs as part of the write pipeline and is performed 81 * in the ZIO_STAGE_WRITE_BP_INIT stage. 82 * 83 * Dedup: 84 * Dedup reads are handled by the ZIO_STAGE_DDT_READ_START and 85 * ZIO_STAGE_DDT_READ_DONE stages. These stages are added to an existing 86 * read pipeline if the dedup bit is set on the block pointer. 87 * Writing a dedup block is performed by the ZIO_STAGE_DDT_WRITE stage 88 * and added to a write pipeline if a user has enabled dedup on that 89 * particular dataset. 90 * 91 * NOP Write: 92 * The NOP write feature is performed by the ZIO_STAGE_NOP_WRITE stage 93 * and is added to an existing write pipeline if a crypographically 94 * secure checksum (i.e. SHA256) is enabled and compression is turned on. 95 * The NOP write stage will compare the checksums of the current data 96 * on-disk (level-0 blocks only) and the data that is currently being written. 97 * If the checksum values are identical then the pipeline is converted to 98 * an interlock pipeline skipping block allocation and bypassing the 99 * physical I/O. The nop write feature can handle writes in either 100 * syncing or open context (i.e. zil writes) and as a result is mutually 101 * exclusive with dedup. 102 */ 103 104 /* 105 * zio pipeline stage definitions 106 */ 107 enum zio_stage { 108 ZIO_STAGE_OPEN = 1 << 0, /* RWFCI */ 109 110 ZIO_STAGE_READ_BP_INIT = 1 << 1, /* R---- */ 111 ZIO_STAGE_FREE_BP_INIT = 1 << 2, /* --F-- */ 112 ZIO_STAGE_ISSUE_ASYNC = 1 << 3, /* RWF-- */ 113 ZIO_STAGE_WRITE_BP_INIT = 1 << 4, /* -W--- */ 114 115 ZIO_STAGE_CHECKSUM_GENERATE = 1 << 5, /* -W--- */ 116 117 ZIO_STAGE_NOP_WRITE = 1 << 6, /* -W--- */ 118 119 ZIO_STAGE_DDT_READ_START = 1 << 7, /* R---- */ 120 ZIO_STAGE_DDT_READ_DONE = 1 << 8, /* R---- */ 121 ZIO_STAGE_DDT_WRITE = 1 << 9, /* -W--- */ 122 ZIO_STAGE_DDT_FREE = 1 << 10, /* --F-- */ 123 124 ZIO_STAGE_GANG_ASSEMBLE = 1 << 11, /* RWFC- */ 125 ZIO_STAGE_GANG_ISSUE = 1 << 12, /* RWFC- */ 126 127 ZIO_STAGE_DVA_ALLOCATE = 1 << 13, /* -W--- */ 128 ZIO_STAGE_DVA_FREE = 1 << 14, /* --F-- */ 129 ZIO_STAGE_DVA_CLAIM = 1 << 15, /* ---C- */ 130 131 ZIO_STAGE_READY = 1 << 16, /* RWFCI */ 132 133 ZIO_STAGE_VDEV_IO_START = 1 << 17, /* RW--I */ 134 ZIO_STAGE_VDEV_IO_DONE = 1 << 18, /* RW--I */ 135 ZIO_STAGE_VDEV_IO_ASSESS = 1 << 19, /* RW--I */ 136 137 ZIO_STAGE_CHECKSUM_VERIFY = 1 << 20, /* R---- */ 138 139 ZIO_STAGE_DONE = 1 << 21 /* RWFCI */ 140 }; 141 142 #define ZIO_INTERLOCK_STAGES \ 143 (ZIO_STAGE_READY | \ 144 ZIO_STAGE_DONE) 145 146 #define ZIO_INTERLOCK_PIPELINE \ 147 ZIO_INTERLOCK_STAGES 148 149 #define ZIO_VDEV_IO_STAGES \ 150 (ZIO_STAGE_VDEV_IO_START | \ 151 ZIO_STAGE_VDEV_IO_DONE | \ 152 ZIO_STAGE_VDEV_IO_ASSESS) 153 154 #define ZIO_VDEV_CHILD_PIPELINE \ 155 (ZIO_VDEV_IO_STAGES | \ 156 ZIO_STAGE_DONE) 157 158 #define ZIO_READ_COMMON_STAGES \ 159 (ZIO_INTERLOCK_STAGES | \ 160 ZIO_VDEV_IO_STAGES | \ 161 ZIO_STAGE_CHECKSUM_VERIFY) 162 163 #define ZIO_READ_PHYS_PIPELINE \ 164 ZIO_READ_COMMON_STAGES 165 166 #define ZIO_READ_PIPELINE \ 167 (ZIO_READ_COMMON_STAGES | \ 168 ZIO_STAGE_READ_BP_INIT) 169 170 #define ZIO_DDT_CHILD_READ_PIPELINE \ 171 ZIO_READ_COMMON_STAGES 172 173 #define ZIO_DDT_READ_PIPELINE \ 174 (ZIO_INTERLOCK_STAGES | \ 175 ZIO_STAGE_READ_BP_INIT | \ 176 ZIO_STAGE_DDT_READ_START | \ 177 ZIO_STAGE_DDT_READ_DONE) 178 179 #define ZIO_WRITE_COMMON_STAGES \ 180 (ZIO_INTERLOCK_STAGES | \ 181 ZIO_VDEV_IO_STAGES | \ 182 ZIO_STAGE_ISSUE_ASYNC | \ 183 ZIO_STAGE_CHECKSUM_GENERATE) 184 185 #define ZIO_WRITE_PHYS_PIPELINE \ 186 ZIO_WRITE_COMMON_STAGES 187 188 #define ZIO_REWRITE_PIPELINE \ 189 (ZIO_WRITE_COMMON_STAGES | \ 190 ZIO_STAGE_WRITE_BP_INIT) 191 192 #define ZIO_WRITE_PIPELINE \ 193 (ZIO_WRITE_COMMON_STAGES | \ 194 ZIO_STAGE_WRITE_BP_INIT | \ 195 ZIO_STAGE_DVA_ALLOCATE) 196 197 #define ZIO_DDT_CHILD_WRITE_PIPELINE \ 198 (ZIO_INTERLOCK_STAGES | \ 199 ZIO_VDEV_IO_STAGES | \ 200 ZIO_STAGE_DVA_ALLOCATE) 201 202 #define ZIO_DDT_WRITE_PIPELINE \ 203 (ZIO_INTERLOCK_STAGES | \ 204 ZIO_STAGE_ISSUE_ASYNC | \ 205 ZIO_STAGE_WRITE_BP_INIT | \ 206 ZIO_STAGE_CHECKSUM_GENERATE | \ 207 ZIO_STAGE_DDT_WRITE) 208 209 #define ZIO_GANG_STAGES \ 210 (ZIO_STAGE_GANG_ASSEMBLE | \ 211 ZIO_STAGE_GANG_ISSUE) 212 213 #define ZIO_FREE_PIPELINE \ 214 (ZIO_INTERLOCK_STAGES | \ 215 ZIO_STAGE_FREE_BP_INIT | \ 216 ZIO_STAGE_DVA_FREE) 217 218 #define ZIO_DDT_FREE_PIPELINE \ 219 (ZIO_INTERLOCK_STAGES | \ 220 ZIO_STAGE_FREE_BP_INIT | \ 221 ZIO_STAGE_ISSUE_ASYNC | \ 222 ZIO_STAGE_DDT_FREE) 223 224 #define ZIO_CLAIM_PIPELINE \ 225 (ZIO_INTERLOCK_STAGES | \ 226 ZIO_STAGE_DVA_CLAIM) 227 228 #define ZIO_IOCTL_PIPELINE \ 229 (ZIO_INTERLOCK_STAGES | \ 230 ZIO_STAGE_VDEV_IO_START | \ 231 ZIO_STAGE_VDEV_IO_ASSESS) 232 233 #define ZIO_BLOCKING_STAGES \ 234 (ZIO_STAGE_DVA_ALLOCATE | \ 235 ZIO_STAGE_DVA_CLAIM | \ 236 ZIO_STAGE_VDEV_IO_START) 237 238 extern void zio_inject_init(void); 239 extern void zio_inject_fini(void); 240 241 #ifdef __cplusplus 242 } 243 #endif 244 245 #endif /* _ZIO_IMPL_H */ 246