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 */ 103 104 /* 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_WRITE_BP_INIT = 1 << 2, /* -W--- */ 112 ZIO_STAGE_FREE_BP_INIT = 1 << 3, /* --F-- */ 113 ZIO_STAGE_ISSUE_ASYNC = 1 << 4, /* RWF-- */ 114 ZIO_STAGE_WRITE_COMPRESS = 1 << 5, /* -W--- */ 115 116 ZIO_STAGE_CHECKSUM_GENERATE = 1 << 6, /* -W--- */ 117 118 ZIO_STAGE_NOP_WRITE = 1 << 7, /* -W--- */ 119 120 ZIO_STAGE_DDT_READ_START = 1 << 8, /* R---- */ 121 ZIO_STAGE_DDT_READ_DONE = 1 << 9, /* R---- */ 122 ZIO_STAGE_DDT_WRITE = 1 << 10, /* -W--- */ 123 ZIO_STAGE_DDT_FREE = 1 << 11, /* --F-- */ 124 125 ZIO_STAGE_GANG_ASSEMBLE = 1 << 12, /* RWFC- */ 126 ZIO_STAGE_GANG_ISSUE = 1 << 13, /* RWFC- */ 127 128 ZIO_STAGE_DVA_THROTTLE = 1 << 14, /* -W--- */ 129 ZIO_STAGE_DVA_ALLOCATE = 1 << 15, /* -W--- */ 130 ZIO_STAGE_DVA_FREE = 1 << 16, /* --F-- */ 131 ZIO_STAGE_DVA_CLAIM = 1 << 17, /* ---C- */ 132 133 ZIO_STAGE_READY = 1 << 18, /* RWFCI */ 134 135 ZIO_STAGE_VDEV_IO_START = 1 << 19, /* RWF-I */ 136 ZIO_STAGE_VDEV_IO_DONE = 1 << 20, /* RWF-I */ 137 ZIO_STAGE_VDEV_IO_ASSESS = 1 << 21, /* RWF-I */ 138 139 ZIO_STAGE_CHECKSUM_VERIFY = 1 << 22, /* R---- */ 140 141 ZIO_STAGE_DONE = 1 << 23 /* RWFCI */ 142 }; 143 144 #define ZIO_INTERLOCK_STAGES \ 145 (ZIO_STAGE_READY | \ 146 ZIO_STAGE_DONE) 147 148 #define ZIO_INTERLOCK_PIPELINE \ 149 ZIO_INTERLOCK_STAGES 150 151 #define ZIO_VDEV_IO_STAGES \ 152 (ZIO_STAGE_VDEV_IO_START | \ 153 ZIO_STAGE_VDEV_IO_DONE | \ 154 ZIO_STAGE_VDEV_IO_ASSESS) 155 156 #define ZIO_VDEV_CHILD_PIPELINE \ 157 (ZIO_VDEV_IO_STAGES | \ 158 ZIO_STAGE_DONE) 159 160 #define ZIO_READ_COMMON_STAGES \ 161 (ZIO_INTERLOCK_STAGES | \ 162 ZIO_VDEV_IO_STAGES | \ 163 ZIO_STAGE_CHECKSUM_VERIFY) 164 165 #define ZIO_READ_PHYS_PIPELINE \ 166 ZIO_READ_COMMON_STAGES 167 168 #define ZIO_READ_PIPELINE \ 169 (ZIO_READ_COMMON_STAGES | \ 170 ZIO_STAGE_READ_BP_INIT) 171 172 #define ZIO_DDT_CHILD_READ_PIPELINE \ 173 ZIO_READ_COMMON_STAGES 174 175 #define ZIO_DDT_READ_PIPELINE \ 176 (ZIO_INTERLOCK_STAGES | \ 177 ZIO_STAGE_READ_BP_INIT | \ 178 ZIO_STAGE_DDT_READ_START | \ 179 ZIO_STAGE_DDT_READ_DONE) 180 181 #define ZIO_WRITE_COMMON_STAGES \ 182 (ZIO_INTERLOCK_STAGES | \ 183 ZIO_VDEV_IO_STAGES | \ 184 ZIO_STAGE_ISSUE_ASYNC | \ 185 ZIO_STAGE_CHECKSUM_GENERATE) 186 187 #define ZIO_WRITE_PHYS_PIPELINE \ 188 ZIO_WRITE_COMMON_STAGES 189 190 #define ZIO_REWRITE_PIPELINE \ 191 (ZIO_WRITE_COMMON_STAGES | \ 192 ZIO_STAGE_WRITE_COMPRESS | \ 193 ZIO_STAGE_WRITE_BP_INIT) 194 195 #define ZIO_WRITE_PIPELINE \ 196 (ZIO_WRITE_COMMON_STAGES | \ 197 ZIO_STAGE_WRITE_BP_INIT | \ 198 ZIO_STAGE_WRITE_COMPRESS | \ 199 ZIO_STAGE_DVA_THROTTLE | \ 200 ZIO_STAGE_DVA_ALLOCATE) 201 202 #define ZIO_DDT_CHILD_WRITE_PIPELINE \ 203 (ZIO_INTERLOCK_STAGES | \ 204 ZIO_VDEV_IO_STAGES | \ 205 ZIO_STAGE_DVA_THROTTLE | \ 206 ZIO_STAGE_DVA_ALLOCATE) 207 208 #define ZIO_DDT_WRITE_PIPELINE \ 209 (ZIO_INTERLOCK_STAGES | \ 210 ZIO_STAGE_WRITE_BP_INIT | \ 211 ZIO_STAGE_ISSUE_ASYNC | \ 212 ZIO_STAGE_WRITE_COMPRESS | \ 213 ZIO_STAGE_CHECKSUM_GENERATE | \ 214 ZIO_STAGE_DDT_WRITE) 215 216 #define ZIO_GANG_STAGES \ 217 (ZIO_STAGE_GANG_ASSEMBLE | \ 218 ZIO_STAGE_GANG_ISSUE) 219 220 #define ZIO_FREE_PIPELINE \ 221 (ZIO_INTERLOCK_STAGES | \ 222 ZIO_STAGE_FREE_BP_INIT | \ 223 ZIO_STAGE_DVA_FREE) 224 225 #define ZIO_FREE_PHYS_PIPELINE \ 226 (ZIO_INTERLOCK_STAGES | \ 227 ZIO_VDEV_IO_STAGES) 228 229 #define ZIO_DDT_FREE_PIPELINE \ 230 (ZIO_INTERLOCK_STAGES | \ 231 ZIO_STAGE_FREE_BP_INIT | \ 232 ZIO_STAGE_ISSUE_ASYNC | \ 233 ZIO_STAGE_DDT_FREE) 234 235 #define ZIO_CLAIM_PIPELINE \ 236 (ZIO_INTERLOCK_STAGES | \ 237 ZIO_STAGE_DVA_CLAIM) 238 239 #define ZIO_IOCTL_PIPELINE \ 240 (ZIO_INTERLOCK_STAGES | \ 241 ZIO_STAGE_VDEV_IO_START | \ 242 ZIO_STAGE_VDEV_IO_ASSESS) 243 244 #define ZIO_BLOCKING_STAGES \ 245 (ZIO_STAGE_DVA_ALLOCATE | \ 246 ZIO_STAGE_DVA_CLAIM | \ 247 ZIO_STAGE_VDEV_IO_START) 248 249 extern void zio_inject_init(void); 250 extern void zio_inject_fini(void); 251 252 #ifdef __cplusplus 253 } 254 #endif 255 256 #endif /* _ZIO_IMPL_H */ 257