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         int                     raid_disks;
  18         spinlock_t              device_lock;
  19
  20         /* geometry */
  21         int                     near_copies;  /* number of copies laid out
  22                                                * raid0 style */
  23         int                     far_copies;   /* number of copies laid out
  24                                                * at large strides across drives
  25                                                */
  26         int                     far_offset;   /* far_copies are offset by 1
  27                                                * stripe instead of many
  28                                                */
  29         int                     copies;       /* near_copies * far_copies.
  30                                                * must be <= raid_disks
  31                                                */
  32         sector_t                stride;       /* distance between far copies.
  33                                                * This is size / far_copies unless
  34                                                * far_offset, in which case it is
  35                                                * 1 stripe.
  36                                                */
  37
  38         sector_t                dev_sectors;  /* temp copy of
  39                                                * mddev->dev_sectors */
  40
  41         int                     chunk_shift; /* shift from chunks to sectors */
  42         sector_t                chunk_mask;
  43
  44         struct list_head        retry_list;
  45         /* queue pending writes and submit them on unplug */
  46         struct bio_list         pending_bio_list;
  47         int                     pending_count;
  48
  49         spinlock_t              resync_lock;
  50         int                     nr_pending;
  51         int                     nr_waiting;
  52         int                     nr_queued;
  53         int                     barrier;
  54         sector_t                next_resync;
  55         int                     fullsync;  /* set to 1 if a full sync is needed,
  56                                             * (fresh device added).
  57                                             * Cleared when a sync completes.
  58                                             */
  59         int                     have_replacement; /* There is at least one
  60                                                    * replacement device.
  61                                                    */
  62         wait_queue_head_t       wait_barrier;
  63
  64         mempool_t               *r10bio_pool;
  65         mempool_t               *r10buf_pool;
  66         struct page             *tmppage;
  67
  68         /* When taking over an array from a different personality, we store
  69          * the new thread here until we fully activate the array.
  70          */
  71         struct md_thread        *thread;
  72 };
  73
  74 /*
  75  * this is our 'private' RAID10 bio.
  76  *
  77  * it contains information about what kind of IO operations were started
  78  * for this RAID10 operation, and about their status:
  79  */
  80
  81 struct r10bio {
  82         atomic_t                remaining; /* 'have we finished' count,
  83                                             * used from IRQ handlers
  84                                             */
  85         sector_t                sector; /* virtual sector number */
  86         int                     sectors;
  87         unsigned long           state;
  88         struct mddev            *mddev;
  89         /*
  90          * original bio going to /dev/mdx
  91          */
  92         struct bio              *master_bio;
  93         /*
  94          * if the IO is in READ direction, then this is where we read
  95          */
  96         int                     read_slot;
  97
  98         struct list_head        retry_list;
  99         /*
 100          * if the IO is in WRITE direction, then multiple bios are used,
 101          * one for each copy.
 102          * When resyncing we also use one for each copy.
 103          * When reconstructing, we use 2 bios, one for read, one for write.
 104          * We choose the number when they are allocated.
 105          * We sometimes need an extra bio to write to the replacement.
 106          */
 107         struct {
 108                 struct bio      *bio;
 109                 union {
 110                         struct bio      *repl_bio; /* used for resync and
 111                                                     * writes */
 112                         struct md_rdev  *rdev;     /* used for reads
 113                                                     * (read_slot >= 0) */
 114                 };
 115                 sector_t        addr;
 116                 int             devnum;
 117         } devs[0];
 118 };
 119
 120 /* when we get a read error on a read-only array, we redirect to another
 121  * device without failing the first device, or trying to over-write to
 122  * correct the read error.  To keep track of bad blocks on a per-bio
 123  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
 124  */
 125 #define IO_BLOCKED ((struct bio*)1)
 126 /* When we successfully write to a known bad-block, we need to remove the
 127  * bad-block marking which must be done from process context.  So we record
 128  * the success by setting devs[n].bio to IO_MADE_GOOD
 129  */
 130 #define IO_MADE_GOOD ((struct bio *)2)
 131
 132 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
 133
 134 /* bits for r10bio.state */
 135 enum r10bio_state {
 136         R10BIO_Uptodate,
 137         R10BIO_IsSync,
 138         R10BIO_IsRecover,
 139         R10BIO_Degraded,
 140 /* Set ReadError on bios that experience a read error
 141  * so that raid10d knows what to do with them.
 142  */
 143         R10BIO_ReadError,
 144 /* If a write for this request means we can clear some
 145  * known-bad-block records, we set this flag.
 146  */
 147         R10BIO_MadeGood,
 148         R10BIO_WriteError,
 149 };
 150 #endif