zio_impl.h

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    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 https://opensource.org/licenses/CDDL-1.0.
   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 #ifdef  __cplusplus
   34 extern "C" {
   35 #endif
   36 
   37 /*
   38  * XXX -- Describe ZFS I/O pipeline here. Fill in as needed.
   39  *
   40  * The ZFS I/O pipeline is comprised of various stages which are defined
   41  * in the zio_stage enum below. The individual stages are used to construct
   42  * these basic I/O operations: Read, Write, Free, Claim, and Ioctl.
   43  *
   44  * I/O operations: (XXX - provide detail for each of the operations)
   45  *
   46  * Read:
   47  * Write:
   48  * Free:
   49  * Claim:
   50  * Ioctl:
   51  *
   52  * Although the most common pipeline are used by the basic I/O operations
   53  * above, there are some helper pipelines (one could consider them
   54  * sub-pipelines) which are used internally by the ZIO module and are
   55  * explained below:
   56  *
   57  * Interlock Pipeline:
   58  * The interlock pipeline is the most basic pipeline and is used by all
   59  * of the I/O operations. The interlock pipeline does not perform any I/O
   60  * and is used to coordinate the dependencies between I/Os that are being
   61  * issued (i.e. the parent/child relationship).
   62  *
   63  * Vdev child Pipeline:
   64  * The vdev child pipeline is responsible for performing the physical I/O.
   65  * It is in this pipeline where the I/O are queued and possibly cached.
   66  *
   67  * In addition to performing I/O, the pipeline is also responsible for
   68  * data transformations. The transformations performed are based on the
   69  * specific properties that user may have selected and modify the
   70  * behavior of the pipeline. Examples of supported transformations are
   71  * compression, dedup, and nop writes. Transformations will either modify
   72  * the data or the pipeline. This list below further describes each of
   73  * the supported transformations:
   74  *
   75  * Compression:
   76  * ZFS supports five different flavors of compression -- gzip, lzjb, lz4, zle,
   77  * and zstd. Compression occurs as part of the write pipeline and is
   78  * performed in the ZIO_STAGE_WRITE_BP_INIT stage.
   79  *
   80  * Dedup:
   81  * Dedup reads are handled by the ZIO_STAGE_DDT_READ_START and
   82  * ZIO_STAGE_DDT_READ_DONE stages. These stages are added to an existing
   83  * read pipeline if the dedup bit is set on the block pointer.
   84  * Writing a dedup block is performed by the ZIO_STAGE_DDT_WRITE stage
   85  * and added to a write pipeline if a user has enabled dedup on that
   86  * particular dataset.
   87  *
   88  * NOP Write:
   89  * The NOP write feature is performed by the ZIO_STAGE_NOP_WRITE stage
   90  * and is added to an existing write pipeline if a cryptographically
   91  * secure checksum (i.e. SHA256) is enabled and compression is turned on.
   92  * The NOP write stage will compare the checksums of the current data
   93  * on-disk (level-0 blocks only) and the data that is currently being written.
   94  * If the checksum values are identical then the pipeline is converted to
   95  * an interlock pipeline skipping block allocation and bypassing the
   96  * physical I/O.  The nop write feature can handle writes in either
   97  * syncing or open context (i.e. zil writes) and as a result is mutually
   98  * exclusive with dedup.
   99  *
  100  * Encryption:
  101  * Encryption and authentication is handled by the ZIO_STAGE_ENCRYPT stage.
  102  * This stage determines how the encryption metadata is stored in the bp.
  103  * Decryption and MAC verification is performed during zio_decrypt() as a
  104  * transform callback. Encryption is mutually exclusive with nopwrite, because
  105  * blocks with the same plaintext will be encrypted with different salts and
  106  * IV's (if dedup is off), and therefore have different ciphertexts. For dedup
  107  * blocks we deterministically generate the IV and salt by performing an HMAC
  108  * of the plaintext, which is computationally expensive, but allows us to keep
  109  * support for encrypted dedup. See the block comment in zio_crypt.c for
  110  * details.
  111  */
  112 
  113 /*
  114  * zio pipeline stage definitions
  115  */
  116 enum zio_stage {
  117         ZIO_STAGE_OPEN                  = 1 << 0,       /* RWFCI */
  118 
  119         ZIO_STAGE_READ_BP_INIT          = 1 << 1,       /* R---- */
  120         ZIO_STAGE_WRITE_BP_INIT         = 1 << 2,       /* -W--- */
  121         ZIO_STAGE_FREE_BP_INIT          = 1 << 3,       /* --F-- */
  122         ZIO_STAGE_ISSUE_ASYNC           = 1 << 4,       /* RWF-- */
  123         ZIO_STAGE_WRITE_COMPRESS        = 1 << 5,       /* -W--- */
  124 
  125         ZIO_STAGE_ENCRYPT               = 1 << 6,       /* -W--- */
  126         ZIO_STAGE_CHECKSUM_GENERATE     = 1 << 7,       /* -W--- */
  127 
  128         ZIO_STAGE_NOP_WRITE             = 1 << 8,       /* -W--- */
  129 
  130         ZIO_STAGE_DDT_READ_START        = 1 << 9,       /* R---- */
  131         ZIO_STAGE_DDT_READ_DONE         = 1 << 10,      /* R---- */
  132         ZIO_STAGE_DDT_WRITE             = 1 << 11,      /* -W--- */
  133         ZIO_STAGE_DDT_FREE              = 1 << 12,      /* --F-- */
  134 
  135         ZIO_STAGE_GANG_ASSEMBLE         = 1 << 13,      /* RWFC- */
  136         ZIO_STAGE_GANG_ISSUE            = 1 << 14,      /* RWFC- */
  137 
  138         ZIO_STAGE_DVA_THROTTLE          = 1 << 15,      /* -W--- */
  139         ZIO_STAGE_DVA_ALLOCATE          = 1 << 16,      /* -W--- */
  140         ZIO_STAGE_DVA_FREE              = 1 << 17,      /* --F-- */
  141         ZIO_STAGE_DVA_CLAIM             = 1 << 18,      /* ---C- */
  142 
  143         ZIO_STAGE_READY                 = 1 << 19,      /* RWFCI */
  144 
  145         ZIO_STAGE_VDEV_IO_START         = 1 << 20,      /* RW--I */
  146         ZIO_STAGE_VDEV_IO_DONE          = 1 << 21,      /* RW--I */
  147         ZIO_STAGE_VDEV_IO_ASSESS        = 1 << 22,      /* RW--I */
  148 
  149         ZIO_STAGE_CHECKSUM_VERIFY       = 1 << 23,      /* R---- */
  150 
  151         ZIO_STAGE_DONE                  = 1 << 24       /* RWFCI */
  152 };
  153 
  154 #define ZIO_INTERLOCK_STAGES                    \
  155         (ZIO_STAGE_READY |                      \
  156         ZIO_STAGE_DONE)
  157 
  158 #define ZIO_INTERLOCK_PIPELINE                  \
  159         ZIO_INTERLOCK_STAGES
  160 
  161 #define ZIO_VDEV_IO_STAGES                      \
  162         (ZIO_STAGE_VDEV_IO_START |              \
  163         ZIO_STAGE_VDEV_IO_DONE |                \
  164         ZIO_STAGE_VDEV_IO_ASSESS)
  165 
  166 #define ZIO_VDEV_CHILD_PIPELINE                 \
  167         (ZIO_VDEV_IO_STAGES |                   \
  168         ZIO_STAGE_DONE)
  169 
  170 #define ZIO_READ_COMMON_STAGES                  \
  171         (ZIO_INTERLOCK_STAGES |                 \
  172         ZIO_VDEV_IO_STAGES |                    \
  173         ZIO_STAGE_CHECKSUM_VERIFY)
  174 
  175 #define ZIO_READ_PHYS_PIPELINE                  \
  176         ZIO_READ_COMMON_STAGES
  177 
  178 #define ZIO_READ_PIPELINE                       \
  179         (ZIO_READ_COMMON_STAGES |               \
  180         ZIO_STAGE_READ_BP_INIT)
  181 
  182 #define ZIO_DDT_CHILD_READ_PIPELINE             \
  183         ZIO_READ_COMMON_STAGES
  184 
  185 #define ZIO_DDT_READ_PIPELINE                   \
  186         (ZIO_INTERLOCK_STAGES |                 \
  187         ZIO_STAGE_READ_BP_INIT |                \
  188         ZIO_STAGE_DDT_READ_START |              \
  189         ZIO_STAGE_DDT_READ_DONE)
  190 
  191 #define ZIO_WRITE_COMMON_STAGES                 \
  192         (ZIO_INTERLOCK_STAGES |                 \
  193         ZIO_VDEV_IO_STAGES |                    \
  194         ZIO_STAGE_ISSUE_ASYNC |                 \
  195         ZIO_STAGE_CHECKSUM_GENERATE)
  196 
  197 #define ZIO_WRITE_PHYS_PIPELINE                 \
  198         ZIO_WRITE_COMMON_STAGES
  199 
  200 #define ZIO_REWRITE_PIPELINE                    \
  201         (ZIO_WRITE_COMMON_STAGES |              \
  202         ZIO_STAGE_WRITE_COMPRESS |              \
  203         ZIO_STAGE_ENCRYPT |                     \
  204         ZIO_STAGE_WRITE_BP_INIT)
  205 
  206 #define ZIO_WRITE_PIPELINE                      \
  207         (ZIO_WRITE_COMMON_STAGES |              \
  208         ZIO_STAGE_WRITE_BP_INIT |               \
  209         ZIO_STAGE_WRITE_COMPRESS |              \
  210         ZIO_STAGE_ENCRYPT |                     \
  211         ZIO_STAGE_DVA_THROTTLE |                \
  212         ZIO_STAGE_DVA_ALLOCATE)
  213 
  214 #define ZIO_DDT_CHILD_WRITE_PIPELINE            \
  215         (ZIO_INTERLOCK_STAGES |                 \
  216         ZIO_VDEV_IO_STAGES |                    \
  217         ZIO_STAGE_DVA_THROTTLE |                \
  218         ZIO_STAGE_DVA_ALLOCATE)
  219 
  220 #define ZIO_DDT_WRITE_PIPELINE                  \
  221         (ZIO_INTERLOCK_STAGES |                 \
  222         ZIO_STAGE_WRITE_BP_INIT |               \
  223         ZIO_STAGE_ISSUE_ASYNC |                 \
  224         ZIO_STAGE_WRITE_COMPRESS |              \
  225         ZIO_STAGE_ENCRYPT |                     \
  226         ZIO_STAGE_CHECKSUM_GENERATE |           \
  227         ZIO_STAGE_DDT_WRITE)
  228 
  229 #define ZIO_GANG_STAGES                         \
  230         (ZIO_STAGE_GANG_ASSEMBLE |              \
  231         ZIO_STAGE_GANG_ISSUE)
  232 
  233 #define ZIO_FREE_PIPELINE                       \
  234         (ZIO_INTERLOCK_STAGES |                 \
  235         ZIO_STAGE_FREE_BP_INIT |                \
  236         ZIO_STAGE_DVA_FREE)
  237 
  238 #define ZIO_DDT_FREE_PIPELINE                   \
  239         (ZIO_INTERLOCK_STAGES |                 \
  240         ZIO_STAGE_FREE_BP_INIT |                \
  241         ZIO_STAGE_ISSUE_ASYNC |                 \
  242         ZIO_STAGE_DDT_FREE)
  243 
  244 #define ZIO_CLAIM_PIPELINE                      \
  245         (ZIO_INTERLOCK_STAGES |                 \
  246         ZIO_STAGE_DVA_CLAIM)
  247 
  248 #define ZIO_IOCTL_PIPELINE                      \
  249         (ZIO_INTERLOCK_STAGES |                 \
  250         ZIO_STAGE_VDEV_IO_START |               \
  251         ZIO_STAGE_VDEV_IO_ASSESS)
  252 
  253 #define ZIO_TRIM_PIPELINE                       \
  254         (ZIO_INTERLOCK_STAGES |                 \
  255         ZIO_STAGE_ISSUE_ASYNC |                 \
  256         ZIO_VDEV_IO_STAGES)
  257 
  258 #define ZIO_BLOCKING_STAGES                     \
  259         (ZIO_STAGE_DVA_ALLOCATE |               \
  260         ZIO_STAGE_DVA_CLAIM |                   \
  261         ZIO_STAGE_VDEV_IO_START)
  262 
  263 extern void zio_inject_init(void);
  264 extern void zio_inject_fini(void);
  265 
  266 #ifdef  __cplusplus
  267 }
  268 #endif
  269 
  270 #endif  /* _ZIO_IMPL_H */
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FreeBSD/Linux Kernel Cross Reference sys/contrib/openzfs/include/sys/zio_impl.h

FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/include/sys/zio_impl.h
