drivers/md/raid10.h

   1 #ifndef _RAID10_H
   2 #define _RAID10_H
   3
   4 struct mirror_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
  14 struct r10conf {
  15         struct mddev            *mddev;
  16         struct mirror_info      *mirrors;
  17         struct mirror_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
  87 struct 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 {
 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 /* when we get a read error on a read-only array, we redirect to another
 127  * device without failing the first device, or trying to over-write to
 128  * correct the read error.  To keep track of bad blocks on a per-bio
 129  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
 130  */
 131 #define IO_BLOCKED ((struct bio*)1)
 132 /* When we successfully write to a known bad-block, we need to remove the
 133  * bad-block marking which must be done from process context.  So we record
 134  * the success by setting devs[n].bio to IO_MADE_GOOD
 135  */
 136 #define IO_MADE_GOOD ((struct bio *)2)
 137
 138 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
 139
 140 /* bits for r10bio.state */
 141 enum r10bio_state {
 142         R10BIO_Uptodate,
 143         R10BIO_IsSync,
 144         R10BIO_IsRecover,
 145         R10BIO_IsReshape,
 146         R10BIO_Degraded,
 147 /* Set ReadError on bios that experience a read error
 148  * so that raid10d knows what to do with them.
 149  */
 150         R10BIO_ReadError,
 151 /* If a write for this request means we can clear some
 152  * known-bad-block records, we set this flag.
 153  */
 154         R10BIO_MadeGood,
 155         R10BIO_WriteError,
 156 /* During a reshape we might be performing IO on the
 157  * 'previous' part of the array, in which case this
 158  * flag is set
 159  */
 160         R10BIO_Previous,
 161 };
 162 #endif