Root/drivers/md/raid10.h

1#ifndef _RAID10_H
2#define _RAID10_H
3
4struct raid10_info {
5    struct md_rdev *rdev, *replacement;
6    sector_t head_position;
7    int recovery_disabled; /* matches
8                         * mddev->recovery_disabled
9                         * when we shouldn't try
10                         * recovering this device.
11                         */
12};
13
14struct r10conf {
15    struct mddev *mddev;
16    struct raid10_info *mirrors;
17    struct raid10_info *mirrors_new, *mirrors_old;
18    spinlock_t device_lock;
19
20    /* geometry */
21    struct geom {
22        int raid_disks;
23        int near_copies; /* number of copies laid out
24                           * raid0 style */
25        int far_copies; /* number of copies laid out
26                           * at large strides across drives
27                           */
28        int far_offset; /* far_copies are offset by 1
29                           * stripe instead of many
30                           */
31        sector_t stride; /* distance between far copies.
32                           * This is size / far_copies unless
33                           * far_offset, in which case it is
34                           * 1 stripe.
35                           */
36        int far_set_size; /* The number of devices in a set,
37                           * where a 'set' are devices that
38                           * contain far/offset copies of
39                           * each other.
40                           */
41        int chunk_shift; /* shift from chunks to sectors */
42        sector_t chunk_mask;
43    } prev, geo;
44    int copies; /* near_copies * far_copies.
45                           * must be <= raid_disks
46                           */
47
48    sector_t dev_sectors; /* temp copy of
49                           * mddev->dev_sectors */
50    sector_t reshape_progress;
51    sector_t reshape_safe;
52    unsigned long reshape_checkpoint;
53    sector_t offset_diff;
54
55    struct list_head retry_list;
56    /* queue pending writes and submit them on unplug */
57    struct bio_list pending_bio_list;
58    int pending_count;
59
60    spinlock_t resync_lock;
61    int nr_pending;
62    int nr_waiting;
63    int nr_queued;
64    int barrier;
65    sector_t next_resync;
66    int fullsync; /* set to 1 if a full sync is needed,
67                        * (fresh device added).
68                        * Cleared when a sync completes.
69                        */
70    int have_replacement; /* There is at least one
71                           * replacement device.
72                           */
73    wait_queue_head_t wait_barrier;
74
75    mempool_t *r10bio_pool;
76    mempool_t *r10buf_pool;
77    struct page *tmppage;
78
79    /* When taking over an array from a different personality, we store
80     * the new thread here until we fully activate the array.
81     */
82    struct md_thread *thread;
83};
84
85/*
86 * this is our 'private' RAID10 bio.
87 *
88 * it contains information about what kind of IO operations were started
89 * for this RAID10 operation, and about their status:
90 */
91
92struct r10bio {
93    atomic_t remaining; /* 'have we finished' count,
94                        * used from IRQ handlers
95                        */
96    sector_t sector; /* virtual sector number */
97    int sectors;
98    unsigned long state;
99    struct mddev *mddev;
100    /*
101     * original bio going to /dev/mdx
102     */
103    struct bio *master_bio;
104    /*
105     * if the IO is in READ direction, then this is where we read
106     */
107    int read_slot;
108
109    struct list_head retry_list;
110    /*
111     * if the IO is in WRITE direction, then multiple bios are used,
112     * one for each copy.
113     * When resyncing we also use one for each copy.
114     * When reconstructing, we use 2 bios, one for read, one for write.
115     * We choose the number when they are allocated.
116     * We sometimes need an extra bio to write to the replacement.
117     */
118    struct r10dev {
119        struct bio *bio;
120        union {
121            struct bio *repl_bio; /* used for resync and
122                            * writes */
123            struct md_rdev *rdev; /* used for reads
124                            * (read_slot >= 0) */
125        };
126        sector_t addr;
127        int devnum;
128    } devs[0];
129};
130
131/* bits for r10bio.state */
132enum r10bio_state {
133    R10BIO_Uptodate,
134    R10BIO_IsSync,
135    R10BIO_IsRecover,
136    R10BIO_IsReshape,
137    R10BIO_Degraded,
138/* Set ReadError on bios that experience a read error
139 * so that raid10d knows what to do with them.
140 */
141    R10BIO_ReadError,
142/* If a write for this request means we can clear some
143 * known-bad-block records, we set this flag.
144 */
145    R10BIO_MadeGood,
146    R10BIO_WriteError,
147/* During a reshape we might be performing IO on the
148 * 'previous' part of the array, in which case this
149 * flag is set
150 */
151    R10BIO_Previous,
152};
153
154extern int md_raid10_congested(struct mddev *mddev, int bits);
155
156#endif
157

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