include/linux/raid/raid10.h

   1 #ifndef _RAID10_H
   2 #define _RAID10_H
   3
   4 #include <linux/raid/md.h>
   5
   6 typedef struct mirror_info mirror_info_t;
   7
   8 struct mirror_info {
   9         mdk_rdev_t      *rdev;
  10         sector_t        head_position;
  11 };
  12
  13 typedef struct r10bio_s r10bio_t;
  14
  15 struct r10_private_data_s {
  16         mddev_t                 *mddev;
  17         mirror_info_t           *mirrors;
  18         int                     raid_disks;
  19         int                     working_disks;
  20         spinlock_t              device_lock;
  21
  22         /* geometry */
  23         int                     near_copies;  /* number of copies layed out raid0 style */
  24         int                     far_copies;   /* number of copies layed out
  25                                                * at large strides across drives
  26                                                */
  27         int                     far_offset;   /* far_copies are offset by 1 stripe
  28                                                * instead of many
  29                                                */
  30         int                     copies;       /* near_copies * far_copies.
  31                                                * must be <= raid_disks
  32                                                */
  33         sector_t                stride;       /* distance between far copies.
  34                                                * This is size / far_copies unless
  35                                                * far_offset, in which case it is
  36                                                * 1 stripe.
  37                                                */
  38
  39         int chunk_shift; /* shift from chunks to sectors */
  40         sector_t chunk_mask;
  41
  42         struct list_head        retry_list;
  43         /* queue pending writes and submit them on unplug */
  44         struct bio_list         pending_bio_list;
  45
  46
  47         spinlock_t              resync_lock;
  48         int nr_pending;
  49         int nr_waiting;
  50         int nr_queued;
  51         int barrier;
  52         sector_t                next_resync;
  53         int                     fullsync;  /* set to 1 if a full sync is needed,
  54                                             * (fresh device added).
  55                                             * Cleared when a sync completes.
  56                                             */
  57
  58         wait_queue_head_t       wait_barrier;
  59
  60         mempool_t *r10bio_pool;
  61         mempool_t *r10buf_pool;
  62         struct page             *tmppage;
  63 };
  64
  65 typedef struct r10_private_data_s conf_t;
  66
  67 /*
  68  * this is the only point in the RAID code where we violate
  69  * C type safety. mddev->private is an 'opaque' pointer.
  70  */
  71 #define mddev_to_conf(mddev) ((conf_t *) mddev->private)
  72
  73 /*
  74  * this is our 'private' RAID10 bio.
  75  *
  76  * it contains information about what kind of IO operations were started
  77  * for this RAID10 operation, and about their status:
  78  */
  79
  80 struct r10bio_s {
  81         atomic_t                remaining; /* 'have we finished' count,
  82                                             * used from IRQ handlers
  83                                             */
  84         sector_t                sector; /* virtual sector number */
  85         int                     sectors;
  86         unsigned long           state;
  87         mddev_t                 *mddev;
  88         /*
  89          * original bio going to /dev/mdx
  90          */
  91         struct bio              *master_bio;
  92         /*
  93          * if the IO is in READ direction, then this is where we read
  94          */
  95         int                     read_slot;
  96
  97         struct list_head        retry_list;
  98         /*
  99          * if the IO is in WRITE direction, then multiple bios are used,
 100          * one for each copy.
 101          * When resyncing we also use one for each copy.
 102          * When reconstructing, we use 2 bios, one for read, one for write.
 103          * We choose the number when they are allocated.
 104          */
 105         struct {
 106                 struct bio              *bio;
 107                 sector_t addr;
 108                 int devnum;
 109         } devs[0];
 110 };
 111
 112 /* when we get a read error on a read-only array, we redirect to another
 113  * device without failing the first device, or trying to over-write to
 114  * correct the read error.  To keep track of bad blocks on a per-bio
 115  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
 116  */
 117 #define IO_BLOCKED ((struct bio*)1)
 118
 119 /* bits for r10bio.state */
 120 #define R10BIO_Uptodate 0
 121 #define R10BIO_IsSync   1
 122 #define R10BIO_IsRecover 2
 123 #define R10BIO_Degraded 3
 124 #endif