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        /* A separate list of r1bio which just need raid_end_bio_io called.
  57         * This mustn't happen for writes which had any errors if the superblock
  58         * needs to be written.
  59         */
  60        struct list_head        bio_end_io_list;
  61
  62        /* queue pending writes and submit them on unplug */
  63        struct bio_list         pending_bio_list;
  64        int                     pending_count;
  65
  66        spinlock_t              resync_lock;
  67        atomic_t                nr_pending;
  68        int                     nr_waiting;
  69        int                     nr_queued;
  70        int                     barrier;
  71        int                     array_freeze_pending;
  72        sector_t                next_resync;
  73        int                     fullsync;  /* set to 1 if a full sync is needed,
  74                                            * (fresh device added).
  75                                            * Cleared when a sync completes.
  76                                            */
  77        int                     have_replacement; /* There is at least one
  78                                                   * replacement device.
  79                                                   */
  80        wait_queue_head_t       wait_barrier;
  81
  82        mempool_t               *r10bio_pool;
  83        mempool_t               *r10buf_pool;
  84        struct page             *tmppage;
  85
  86        /* When taking over an array from a different personality, we store
  87         * the new thread here until we fully activate the array.
  88         */
  89        struct md_thread        *thread;
  90};
  91
  92/*
  93 * this is our 'private' RAID10 bio.
  94 *
  95 * it contains information about what kind of IO operations were started
  96 * for this RAID10 operation, and about their status:
  97 */
  98
  99struct r10bio {
 100        atomic_t                remaining; /* 'have we finished' count,
 101                                            * used from IRQ handlers
 102                                            */
 103        sector_t                sector; /* virtual sector number */
 104        int                     sectors;
 105        unsigned long           state;
 106        struct mddev            *mddev;
 107        /*
 108         * original bio going to /dev/mdx
 109         */
 110        struct bio              *master_bio;
 111        /*
 112         * if the IO is in READ direction, then this is where we read
 113         */
 114        int                     read_slot;
 115
 116        struct list_head        retry_list;
 117        /*
 118         * if the IO is in WRITE direction, then multiple bios are used,
 119         * one for each copy.
 120         * When resyncing we also use one for each copy.
 121         * When reconstructing, we use 2 bios, one for read, one for write.
 122         * We choose the number when they are allocated.
 123         * We sometimes need an extra bio to write to the replacement.
 124         */
 125        struct r10dev {
 126                struct bio      *bio;
 127                union {
 128                        struct bio      *repl_bio; /* used for resync and
 129                                                    * writes */
 130                        struct md_rdev  *rdev;     /* used for reads
 131                                                    * (read_slot >= 0) */
 132                };
 133                sector_t        addr;
 134                int             devnum;
 135        } devs[0];
 136};
 137
 138/* bits for r10bio.state */
 139enum r10bio_state {
 140        R10BIO_Uptodate,
 141        R10BIO_IsSync,
 142        R10BIO_IsRecover,
 143        R10BIO_IsReshape,
 144        R10BIO_Degraded,
 145/* Set ReadError on bios that experience a read error
 146 * so that raid10d knows what to do with them.
 147 */
 148        R10BIO_ReadError,
 149/* If a write for this request means we can clear some
 150 * known-bad-block records, we set this flag.
 151 */
 152        R10BIO_MadeGood,
 153        R10BIO_WriteError,
 154/* During a reshape we might be performing IO on the
 155 * 'previous' part of the array, in which case this
 156 * flag is set
 157 */
 158        R10BIO_Previous,
 159/* failfast devices did receive failfast requests. */
 160        R10BIO_FailFast,
 161};
 162#endif
 163