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
18 struct raid10_info {
19 struct md_rdev *rdev, *replacement;
20 sector_t head_position;
21 int recovery_disabled; /* matches
22 * mddev->recovery_disabled
23 * when we shouldn't try
24 * recovering this device.
25 */
26 };
27
28 struct r10conf {
29 struct mddev *mddev;
30 struct raid10_info *mirrors;
31 struct raid10_info *mirrors_new, *mirrors_old;
32 spinlock_t device_lock;
33
34 /* geometry */
35 struct geom {
36 int raid_disks;
37 int near_copies; /* number of copies laid out
38 * raid0 style */
39 int far_copies; /* number of copies laid out
40 * at large strides across drives
41 */
42 int far_offset; /* far_copies are offset by 1
43 * stripe instead of many
44 */
45 sector_t stride; /* distance between far copies.
46 * This is size / far_copies unless
47 * far_offset, in which case it is
48 * 1 stripe.
49 */
50 int far_set_size; /* The number of devices in a set,
51 * where a 'set' are devices that
52 * contain far/offset copies of
53 * each other.
54 */
55 int chunk_shift; /* shift from chunks to sectors */
56 sector_t chunk_mask;
57 } prev, geo;
58 int copies; /* near_copies * far_copies.
59 * must be <= raid_disks
60 */
61
62 sector_t dev_sectors; /* temp copy of
63 * mddev->dev_sectors */
64 sector_t reshape_progress;
65 sector_t reshape_safe;
66 unsigned long reshape_checkpoint;
67 sector_t offset_diff;
68
69 struct list_head retry_list;
70 /* A separate list of r1bio which just need raid_end_bio_io called.
71 * This mustn't happen for writes which had any errors if the superblock
72 * needs to be written.
73 */
74 struct list_head bio_end_io_list;
75
76 /* queue pending writes and submit them on unplug */
77 struct bio_list pending_bio_list;
78 int pending_count;
79
80 spinlock_t resync_lock;
81 atomic_t nr_pending;
82 int nr_waiting;
83 int nr_queued;
84 int barrier;
85 int array_freeze_pending;
86 sector_t next_resync;
87 int fullsync; /* set to 1 if a full sync is needed,
88 * (fresh device added).
89 * Cleared when a sync completes.
90 */
91 int have_replacement; /* There is at least one
92 * replacement device.
93 */
94 wait_queue_head_t wait_barrier;
95
96 mempool_t r10bio_pool;
97 mempool_t r10buf_pool;
98 struct page *tmppage;
99 struct bio_set bio_split;
100
101 /* When taking over an array from a different personality, we store
102 * the new thread here until we fully activate the array.
103 */
104 struct md_thread *thread;
105
106 /*
107 * Keep track of cluster resync window to send to other nodes.
108 */
109 sector_t cluster_sync_low;
110 sector_t cluster_sync_high;
111 };
112
113 /*
114 * this is our 'private' RAID10 bio.
115 *
116 * it contains information about what kind of IO operations were started
117 * for this RAID10 operation, and about their status:
118 */
119
120 struct r10bio {
121 atomic_t remaining; /* 'have we finished' count,
122 * used from IRQ handlers
123 */
124 sector_t sector; /* virtual sector number */
125 int sectors;
126 unsigned long state;
127 struct mddev *mddev;
128 /*
129 * original bio going to /dev/mdx
130 */
131 struct bio *master_bio;
132 /*
133 * if the IO is in READ direction, then this is where we read
134 */
135 int read_slot;
136
137 struct list_head retry_list;
138 /*
139 * if the IO is in WRITE direction, then multiple bios are used,
140 * one for each copy.
141 * When resyncing we also use one for each copy.
142 * When reconstructing, we use 2 bios, one for read, one for write.
143 * We choose the number when they are allocated.
144 * We sometimes need an extra bio to write to the replacement.
145 */
146 struct r10dev {
147 struct bio *bio;
148 union {
149 struct bio *repl_bio; /* used for resync and
150 * writes */
151 struct md_rdev *rdev; /* used for reads
152 * (read_slot >= 0) */
153 };
154 sector_t addr;
155 int devnum;
156 } devs[0];
157 };
158
159 /* bits for r10bio.state */
160 enum r10bio_state {
161 R10BIO_Uptodate,
162 R10BIO_IsSync,
163 R10BIO_IsRecover,
164 R10BIO_IsReshape,
165 R10BIO_Degraded,
166 /* Set ReadError on bios that experience a read error
167 * so that raid10d knows what to do with them.
168 */
169 R10BIO_ReadError,
170 /* If a write for this request means we can clear some
171 * known-bad-block records, we set this flag.
172 */
173 R10BIO_MadeGood,
174 R10BIO_WriteError,
175 /* During a reshape we might be performing IO on the
176 * 'previous' part of the array, in which case this
177 * flag is set
178 */
179 R10BIO_Previous,
180 /* failfast devices did receive failfast requests. */
181 R10BIO_FailFast,
182 };
183 #endif