linux/drivers/md/raid10.h
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   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             chunk_shift; /* shift from chunks to sectors */
  37                sector_t        chunk_mask;
  38        } prev, geo;
  39        int                     copies;       /* near_copies * far_copies.
  40                                               * must be <= raid_disks
  41                                               */
  42
  43        sector_t                dev_sectors;  /* temp copy of
  44                                               * mddev->dev_sectors */
  45        sector_t                reshape_progress;
  46        sector_t                reshape_safe;
  47        unsigned long           reshape_checkpoint;
  48        sector_t                offset_diff;
  49
  50        struct list_head        retry_list;
  51        /* queue pending writes and submit them on unplug */
  52        struct bio_list         pending_bio_list;
  53        int                     pending_count;
  54
  55        spinlock_t              resync_lock;
  56        int                     nr_pending;
  57        int                     nr_waiting;
  58        int                     nr_queued;
  59        int                     barrier;
  60        sector_t                next_resync;
  61        int                     fullsync;  /* set to 1 if a full sync is needed,
  62                                            * (fresh device added).
  63                                            * Cleared when a sync completes.
  64                                            */
  65        int                     have_replacement; /* There is at least one
  66                                                   * replacement device.
  67                                                   */
  68        wait_queue_head_t       wait_barrier;
  69
  70        mempool_t               *r10bio_pool;
  71        mempool_t               *r10buf_pool;
  72        struct page             *tmppage;
  73
  74        /* When taking over an array from a different personality, we store
  75         * the new thread here until we fully activate the array.
  76         */
  77        struct md_thread        *thread;
  78};
  79
  80/*
  81 * this is our 'private' RAID10 bio.
  82 *
  83 * it contains information about what kind of IO operations were started
  84 * for this RAID10 operation, and about their status:
  85 */
  86
  87struct r10bio {
  88        atomic_t                remaining; /* 'have we finished' count,
  89                                            * used from IRQ handlers
  90                                            */
  91        sector_t                sector; /* virtual sector number */
  92        int                     sectors;
  93        unsigned long           state;
  94        struct mddev            *mddev;
  95        /*
  96         * original bio going to /dev/mdx
  97         */
  98        struct bio              *master_bio;
  99        /*
 100         * if the IO is in READ direction, then this is where we read
 101         */
 102        int                     read_slot;
 103
 104        struct list_head        retry_list;
 105        /*
 106         * if the IO is in WRITE direction, then multiple bios are used,
 107         * one for each copy.
 108         * When resyncing we also use one for each copy.
 109         * When reconstructing, we use 2 bios, one for read, one for write.
 110         * We choose the number when they are allocated.
 111         * We sometimes need an extra bio to write to the replacement.
 112         */
 113        struct r10dev {
 114                struct bio      *bio;
 115                union {
 116                        struct bio      *repl_bio; /* used for resync and
 117                                                    * writes */
 118                        struct md_rdev  *rdev;     /* used for reads
 119                                                    * (read_slot >= 0) */
 120                };
 121                sector_t        addr;
 122                int             devnum;
 123        } devs[0];
 124};
 125
 126/* bits for r10bio.state */
 127enum r10bio_state {
 128        R10BIO_Uptodate,
 129        R10BIO_IsSync,
 130        R10BIO_IsRecover,
 131        R10BIO_IsReshape,
 132        R10BIO_Degraded,
 133/* Set ReadError on bios that experience a read error
 134 * so that raid10d knows what to do with them.
 135 */
 136        R10BIO_ReadError,
 137/* If a write for this request means we can clear some
 138 * known-bad-block records, we set this flag.
 139 */
 140        R10BIO_MadeGood,
 141        R10BIO_WriteError,
 142/* During a reshape we might be performing IO on the
 143 * 'previous' part of the array, in which case this
 144 * flag is set
 145 */
 146        R10BIO_Previous,
 147};
 148
 149extern int md_raid10_congested(struct mddev *mddev, int bits);
 150
 151#endif
 152
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