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 */