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