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) 2012, 2015 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 * Encryption: 104 * Encryption and authentication is handled by the ZIO_STAGE_ENCRYPT stage. 105 * This stage determines how the encryption metadata is stored in the bp. 106 * Decryption and MAC verification is performed during zio_decrypt() as a 107 * transform callback. Encryption is mutually exclusive with nopwrite, because 108 * blocks with the same plaintext will be encrypted with different salts and 109 * IV's (if dedup is off), and therefore have different ciphertexts. For dedup 110 * blocks we deterministically generate the IV and salt by performing an HMAC 111 * of the plaintext, which is computationally expensive, but allows us to keep 112 * support for encrypted dedup. See the block comment in zio_crypt.c for 113 * details. 114 */ 115 116 /* 117 * zio pipeline stage definitions 118 */ 119 enum zio_stage { 120 ZIO_STAGE_OPEN = 1 << 0, /* RWFCI */ 121 122 ZIO_STAGE_READ_BP_INIT = 1 << 1, /* R---- */ 123 ZIO_STAGE_WRITE_BP_INIT = 1 << 2, /* -W--- */ 124 ZIO_STAGE_FREE_BP_INIT = 1 << 3, /* --F-- */ 125 ZIO_STAGE_ISSUE_ASYNC = 1 << 4, /* RWF-- */ 126 ZIO_STAGE_WRITE_COMPRESS = 1 << 5, /* -W--- */ 127 128 ZIO_STAGE_ENCRYPT = 1 << 6, /* -W--- */ 129 ZIO_STAGE_CHECKSUM_GENERATE = 1 << 7, /* -W--- */ 130 131 ZIO_STAGE_NOP_WRITE = 1 << 8, /* -W--- */ 132 133 ZIO_STAGE_DDT_READ_START = 1 << 9, /* R---- */ 134 ZIO_STAGE_DDT_READ_DONE = 1 << 10, /* R---- */ 135 ZIO_STAGE_DDT_WRITE = 1 << 11, /* -W--- */ 136 ZIO_STAGE_DDT_FREE = 1 << 12, /* --F-- */ 137 138 ZIO_STAGE_GANG_ASSEMBLE = 1 << 13, /* RWFC- */ 139 ZIO_STAGE_GANG_ISSUE = 1 << 14, /* RWFC- */ 140 141 ZIO_STAGE_DVA_THROTTLE = 1 << 15, /* -W--- */ 142 ZIO_STAGE_DVA_ALLOCATE = 1 << 16, /* -W--- */ 143 ZIO_STAGE_DVA_FREE = 1 << 17, /* --F-- */ 144 ZIO_STAGE_DVA_CLAIM = 1 << 18, /* ---C- */ 145 146 ZIO_STAGE_READY = 1 << 19, /* RWFCI */ 147 148 ZIO_STAGE_VDEV_IO_START = 1 << 20, /* RW--I */ 149 ZIO_STAGE_VDEV_IO_DONE = 1 << 21, /* RW--I */ 150 ZIO_STAGE_VDEV_IO_ASSESS = 1 << 22, /* RW--I */ 151 152 ZIO_STAGE_CHECKSUM_VERIFY = 1 << 23, /* R---- */ 153 154 ZIO_STAGE_DONE = 1 << 24 /* RWFCI */ 155 }; 156 157 #define ZIO_INTERLOCK_STAGES \ 158 (ZIO_STAGE_READY | \ 159 ZIO_STAGE_DONE) 160 161 #define ZIO_INTERLOCK_PIPELINE \ 162 ZIO_INTERLOCK_STAGES 163 164 #define ZIO_VDEV_IO_STAGES \ 165 (ZIO_STAGE_VDEV_IO_START | \ 166 ZIO_STAGE_VDEV_IO_DONE | \ 167 ZIO_STAGE_VDEV_IO_ASSESS) 168 169 #define ZIO_VDEV_CHILD_PIPELINE \ 170 (ZIO_VDEV_IO_STAGES | \ 171 ZIO_STAGE_DONE) 172 173 #define ZIO_READ_COMMON_STAGES \ 174 (ZIO_INTERLOCK_STAGES | \ 175 ZIO_VDEV_IO_STAGES | \ 176 ZIO_STAGE_CHECKSUM_VERIFY) 177 178 #define ZIO_READ_PHYS_PIPELINE \ 179 ZIO_READ_COMMON_STAGES 180 181 #define ZIO_READ_PIPELINE \ 182 (ZIO_READ_COMMON_STAGES | \ 183 ZIO_STAGE_READ_BP_INIT) 184 185 #define ZIO_DDT_CHILD_READ_PIPELINE \ 186 ZIO_READ_COMMON_STAGES 187 188 #define ZIO_DDT_READ_PIPELINE \ 189 (ZIO_INTERLOCK_STAGES | \ 190 ZIO_STAGE_READ_BP_INIT | \ 191 ZIO_STAGE_DDT_READ_START | \ 192 ZIO_STAGE_DDT_READ_DONE) 193 194 #define ZIO_WRITE_COMMON_STAGES \ 195 (ZIO_INTERLOCK_STAGES | \ 196 ZIO_VDEV_IO_STAGES | \ 197 ZIO_STAGE_ISSUE_ASYNC | \ 198 ZIO_STAGE_CHECKSUM_GENERATE) 199 200 #define ZIO_WRITE_PHYS_PIPELINE \ 201 ZIO_WRITE_COMMON_STAGES 202 203 #define ZIO_REWRITE_PIPELINE \ 204 (ZIO_WRITE_COMMON_STAGES | \ 205 ZIO_STAGE_WRITE_COMPRESS | \ 206 ZIO_STAGE_ENCRYPT | \ 207 ZIO_STAGE_WRITE_BP_INIT) 208 209 #define ZIO_WRITE_PIPELINE \ 210 (ZIO_WRITE_COMMON_STAGES | \ 211 ZIO_STAGE_WRITE_BP_INIT | \ 212 ZIO_STAGE_WRITE_COMPRESS | \ 213 ZIO_STAGE_ENCRYPT | \ 214 ZIO_STAGE_DVA_THROTTLE | \ 215 ZIO_STAGE_DVA_ALLOCATE) 216 217 #define ZIO_DDT_CHILD_WRITE_PIPELINE \ 218 (ZIO_INTERLOCK_STAGES | \ 219 ZIO_VDEV_IO_STAGES | \ 220 ZIO_STAGE_DVA_THROTTLE | \ 221 ZIO_STAGE_DVA_ALLOCATE) 222 223 #define ZIO_DDT_WRITE_PIPELINE \ 224 (ZIO_INTERLOCK_STAGES | \ 225 ZIO_STAGE_WRITE_BP_INIT | \ 226 ZIO_STAGE_ISSUE_ASYNC | \ 227 ZIO_STAGE_WRITE_COMPRESS | \ 228 ZIO_STAGE_ENCRYPT | \ 229 ZIO_STAGE_CHECKSUM_GENERATE | \ 230 ZIO_STAGE_DDT_WRITE) 231 232 #define ZIO_GANG_STAGES \ 233 (ZIO_STAGE_GANG_ASSEMBLE | \ 234 ZIO_STAGE_GANG_ISSUE) 235 236 #define ZIO_FREE_PIPELINE \ 237 (ZIO_INTERLOCK_STAGES | \ 238 ZIO_STAGE_FREE_BP_INIT | \ 239 ZIO_STAGE_DVA_FREE) 240 241 #define ZIO_DDT_FREE_PIPELINE \ 242 (ZIO_INTERLOCK_STAGES | \ 243 ZIO_STAGE_FREE_BP_INIT | \ 244 ZIO_STAGE_ISSUE_ASYNC | \ 245 ZIO_STAGE_DDT_FREE) 246 247 #define ZIO_CLAIM_PIPELINE \ 248 (ZIO_INTERLOCK_STAGES | \ 249 ZIO_STAGE_DVA_CLAIM) 250 251 #define ZIO_IOCTL_PIPELINE \ 252 (ZIO_INTERLOCK_STAGES | \ 253 ZIO_STAGE_VDEV_IO_START | \ 254 ZIO_STAGE_VDEV_IO_ASSESS) 255 256 #define ZIO_TRIM_PIPELINE \ 257 (ZIO_INTERLOCK_STAGES | \ 258 ZIO_STAGE_ISSUE_ASYNC | \ 259 ZIO_VDEV_IO_STAGES) 260 261 #define ZIO_BLOCKING_STAGES \ 262 (ZIO_STAGE_DVA_ALLOCATE | \ 263 ZIO_STAGE_DVA_CLAIM | \ 264 ZIO_STAGE_VDEV_IO_START) 265 266 extern void zio_inject_init(void); 267 extern void zio_inject_fini(void); 268 269 #ifdef __cplusplus 270 } 271 #endif 272 273 #endif /* _ZIO_IMPL_H */ 274