kernel/fs/zfs/sys/zio_impl.h

   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,      /* RW--I */
 136         ZIO_STAGE_VDEV_IO_DONE          = 1 << 20,      /* RW--I */
 137         ZIO_STAGE_VDEV_IO_ASSESS        = 1 << 21,      /* RW--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_DDT_FREE_PIPELINE                   \
 226         (ZIO_INTERLOCK_STAGES |                 \
 227         ZIO_STAGE_FREE_BP_INIT |                \
 228         ZIO_STAGE_ISSUE_ASYNC |                 \
 229         ZIO_STAGE_DDT_FREE)
 230
 231 #define ZIO_CLAIM_PIPELINE                      \
 232         (ZIO_INTERLOCK_STAGES |                 \
 233         ZIO_STAGE_DVA_CLAIM)
 234
 235 #define ZIO_IOCTL_PIPELINE                      \
 236         (ZIO_INTERLOCK_STAGES |                 \
 237         ZIO_STAGE_VDEV_IO_START |               \
 238         ZIO_STAGE_VDEV_IO_ASSESS)
 239
 240 #define ZIO_BLOCKING_STAGES                     \
 241         (ZIO_STAGE_DVA_ALLOCATE |               \
 242         ZIO_STAGE_DVA_CLAIM |                   \
 243         ZIO_STAGE_VDEV_IO_START)
 244
 245 extern void zio_inject_init(void);
 246 extern void zio_inject_fini(void);
 247
 248 #ifdef  __cplusplus
 249 }
 250 #endif
 251
 252 #endif  /* _ZIO_IMPL_H */