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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _RAID10_H
3#define _RAID10_H
4
5/* Note: raid10_info.rdev can be set to NULL asynchronously by
6 * raid10_remove_disk.
7 * There are three safe ways to access raid10_info.rdev.
8 * 1/ when holding mddev->reconfig_mutex
9 * 2/ when resync/recovery/reshape is known to be happening - i.e. in code
10 * that is called as part of performing resync/recovery/reshape.
11 * 3/ while holding rcu_read_lock(), use rcu_dereference to get the pointer
12 * and if it is non-NULL, increment rdev->nr_pending before dropping the
13 * RCU lock.
14 * When .rdev is set to NULL, the nr_pending count checked again and if it has
15 * been incremented, the pointer is put back in .rdev.
16 */
17
18struct raid10_info {
19 struct md_rdev *rdev, *replacement;
20 sector_t head_position;
21};
22
23struct r10conf {
24 struct mddev *mddev;
25 struct raid10_info *mirrors;
26 struct raid10_info *mirrors_new, *mirrors_old;
27 spinlock_t device_lock;
28
29 /* geometry */
30 struct geom {
31 int raid_disks;
32 int near_copies; /* number of copies laid out
33 * raid0 style */
34 int far_copies; /* number of copies laid out
35 * at large strides across drives
36 */
37 int far_offset; /* far_copies are offset by 1
38 * stripe instead of many
39 */
40 sector_t stride; /* distance between far copies.
41 * This is size / far_copies unless
42 * far_offset, in which case it is
43 * 1 stripe.
44 */
45 int far_set_size; /* The number of devices in a set,
46 * where a 'set' are devices that
47 * contain far/offset copies of
48 * each other.
49 */
50 int chunk_shift; /* shift from chunks to sectors */
51 sector_t chunk_mask;
52 } prev, geo;
53 int copies; /* near_copies * far_copies.
54 * must be <= raid_disks
55 */
56
57 sector_t dev_sectors; /* temp copy of
58 * mddev->dev_sectors */
59 sector_t reshape_progress;
60 sector_t reshape_safe;
61 unsigned long reshape_checkpoint;
62 sector_t offset_diff;
63
64 struct list_head retry_list;
65 /* A separate list of r1bio which just need raid_end_bio_io called.
66 * This mustn't happen for writes which had any errors if the superblock
67 * needs to be written.
68 */
69 struct list_head bio_end_io_list;
70
71 /* queue pending writes and submit them on unplug */
72 struct bio_list pending_bio_list;
73
74 seqlock_t resync_lock;
75 atomic_t nr_pending;
76 int nr_waiting;
77 int nr_queued;
78 int barrier;
79 int array_freeze_pending;
80 sector_t next_resync;
81 int fullsync; /* set to 1 if a full sync is needed,
82 * (fresh device added).
83 * Cleared when a sync completes.
84 */
85 int have_replacement; /* There is at least one
86 * replacement device.
87 */
88 wait_queue_head_t wait_barrier;
89
90 mempool_t *r10bio_pool;
91 mempool_t r10buf_pool;
92 struct page *tmppage;
93 struct bio_set bio_split;
94
95 /* When taking over an array from a different personality, we store
96 * the new thread here until we fully activate the array.
97 */
98 struct md_thread __rcu *thread;
99
100 /*
101 * Keep track of cluster resync window to send to other nodes.
102 */
103 sector_t cluster_sync_low;
104 sector_t cluster_sync_high;
105};
106
107/*
108 * this is our 'private' RAID10 bio.
109 *
110 * it contains information about what kind of IO operations were started
111 * for this RAID10 operation, and about their status:
112 */
113
114struct r10bio {
115 atomic_t remaining; /* 'have we finished' count,
116 * used from IRQ handlers
117 */
118 sector_t sector; /* virtual sector number */
119 int sectors;
120 unsigned long state;
121 struct mddev *mddev;
122 /*
123 * original bio going to /dev/mdx
124 */
125 struct bio *master_bio;
126 /*
127 * if the IO is in READ direction, then this is where we read
128 */
129 int read_slot;
130
131 struct list_head retry_list;
132 /*
133 * if the IO is in WRITE direction, then multiple bios are used,
134 * one for each copy.
135 * When resyncing we also use one for each copy.
136 * When reconstructing, we use 2 bios, one for read, one for write.
137 * We choose the number when they are allocated.
138 * We sometimes need an extra bio to write to the replacement.
139 */
140 struct r10dev {
141 struct bio *bio;
142 union {
143 struct bio *repl_bio; /* used for resync and
144 * writes */
145 struct md_rdev *rdev; /* used for reads
146 * (read_slot >= 0) */
147 };
148 sector_t addr;
149 int devnum;
150 } devs[];
151};
152
153/* bits for r10bio.state */
154enum r10bio_state {
155 R10BIO_Uptodate,
156 R10BIO_IsSync,
157 R10BIO_IsRecover,
158 R10BIO_IsReshape,
159/* Set ReadError on bios that experience a read error
160 * so that raid10d knows what to do with them.
161 */
162 R10BIO_ReadError,
163/* For bio_split errors, record that bi_end_io was called. */
164 R10BIO_Returned,
165/* If a write for this request means we can clear some
166 * known-bad-block records, we set this flag.
167 */
168 R10BIO_MadeGood,
169 R10BIO_WriteError,
170/* During a reshape we might be performing IO on the
171 * 'previous' part of the array, in which case this
172 * flag is set
173 */
174 R10BIO_Previous,
175/* failfast devices did receive failfast requests. */
176 R10BIO_FailFast,
177 R10BIO_Discard,
178};
179#endif