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             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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