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zio_impl.h (243503) zio_impl.h (243524)
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

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33#include <sys/zfs_context.h>
34#include <sys/zio.h>
35
36#ifdef __cplusplus
37extern "C" {
38#endif
39
40/*
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

--- 24 unchanged lines hidden (view full) ---

33#include <sys/zfs_context.h>
34#include <sys/zio.h>
35
36#ifdef __cplusplus
37extern "C" {
38#endif
39
40/*
41 * XXX -- Describe ZFS I/O pipleine 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/*
41 * zio pipeline stage definitions
42 */
43enum zio_stage {
44 ZIO_STAGE_OPEN = 1 << 0, /* RWFCI */
45
46 ZIO_STAGE_READ_BP_INIT = 1 << 1, /* R---- */
47 ZIO_STAGE_FREE_BP_INIT = 1 << 2, /* --F-- */
48 ZIO_STAGE_ISSUE_ASYNC = 1 << 3, /* RWF-- */
49 ZIO_STAGE_WRITE_BP_INIT = 1 << 4, /* -W--- */
50
51 ZIO_STAGE_CHECKSUM_GENERATE = 1 << 5, /* -W--- */
52
105 * zio pipeline stage definitions
106 */
107enum 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
53 ZIO_STAGE_DDT_READ_START = 1 << 6, /* R---- */
54 ZIO_STAGE_DDT_READ_DONE = 1 << 7, /* R---- */
55 ZIO_STAGE_DDT_WRITE = 1 << 8, /* -W--- */
56 ZIO_STAGE_DDT_FREE = 1 << 9, /* --F-- */
117 ZIO_STAGE_NOP_WRITE = 1 << 6, /* -W--- */
57
118
58 ZIO_STAGE_GANG_ASSEMBLE = 1 << 10, /* RWFC- */
59 ZIO_STAGE_GANG_ISSUE = 1 << 11, /* RWFC- */
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-- */
60
123
61 ZIO_STAGE_DVA_ALLOCATE = 1 << 12, /* -W--- */
62 ZIO_STAGE_DVA_FREE = 1 << 13, /* --F-- */
63 ZIO_STAGE_DVA_CLAIM = 1 << 14, /* ---C- */
124 ZIO_STAGE_GANG_ASSEMBLE = 1 << 11, /* RWFC- */
125 ZIO_STAGE_GANG_ISSUE = 1 << 12, /* RWFC- */
64
126
65 ZIO_STAGE_READY = 1 << 15, /* RWFCI */
127 ZIO_STAGE_DVA_ALLOCATE = 1 << 13, /* -W--- */
128 ZIO_STAGE_DVA_FREE = 1 << 14, /* --F-- */
129 ZIO_STAGE_DVA_CLAIM = 1 << 15, /* ---C- */
66
130
67 ZIO_STAGE_VDEV_IO_START = 1 << 16, /* RWF-I */
68 ZIO_STAGE_VDEV_IO_DONE = 1 << 17, /* RWF-- */
69 ZIO_STAGE_VDEV_IO_ASSESS = 1 << 18, /* RWF-I */
131 ZIO_STAGE_READY = 1 << 16, /* RWFCI */
70
132
71 ZIO_STAGE_CHECKSUM_VERIFY = 1 << 19, /* R---- */
133 ZIO_STAGE_VDEV_IO_START = 1 << 17, /* RWF-I */
134 ZIO_STAGE_VDEV_IO_DONE = 1 << 18, /* RWF-- */
135 ZIO_STAGE_VDEV_IO_ASSESS = 1 << 19, /* RWF-I */
72
136
73 ZIO_STAGE_DONE = 1 << 20 /* RWFCI */
137 ZIO_STAGE_CHECKSUM_VERIFY = 1 << 20, /* R---- */
138
139 ZIO_STAGE_DONE = 1 << 21 /* RWFCI */
74};
75
76#define ZIO_INTERLOCK_STAGES \
77 (ZIO_STAGE_READY | \
78 ZIO_STAGE_DONE)
79
80#define ZIO_INTERLOCK_PIPELINE \
81 ZIO_INTERLOCK_STAGES

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141
142#define ZIO_INTERLOCK_STAGES \
143 (ZIO_STAGE_READY | \
144 ZIO_STAGE_DONE)
145
146#define ZIO_INTERLOCK_PIPELINE \
147 ZIO_INTERLOCK_STAGES

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