include/linux/raid5.h

   1 #ifndef _RAID5_H
   2 #define _RAID5_H
   3
   4 #ifdef __KERNEL__
   5 #include <linux/md.h>
   6 #include <asm/atomic.h>
   7
   8 struct disk_info {
   9         kdev_t  dev;
  10         int     operational;
  11         int     number;
  12         int     raid_disk;
  13         int     write_only;
  14         int     spare;
  15 };
  16
  17 struct stripe_head {
  18         struct stripe_head      *hash_next, **hash_pprev; /* hash pointers */
  19         struct stripe_head      *free_next;             /* pool of free sh's */
  20         struct buffer_head      *buffer_pool;           /* pool of free buffers */
  21         struct buffer_head      *bh_pool;               /* pool of free bh's */
  22         struct raid5_data       *raid_conf;
  23         struct buffer_head      *bh_old[MD_SB_DISKS];   /* disk image */
  24         struct buffer_head      *bh_new[MD_SB_DISKS];   /* buffers of the MD device (present in buffer cache) */
  25         struct buffer_head      *bh_copy[MD_SB_DISKS];  /* copy on write of bh_new (bh_new can change from under us) */
  26         struct buffer_head      *bh_req[MD_SB_DISKS];   /* copy of bh_new (only the buffer heads), queued to the lower levels */
  27         int                     cmd_new[MD_SB_DISKS];   /* READ/WRITE for new */
  28         int                     new[MD_SB_DISKS];       /* buffer added since the last handle_stripe() */
  29         unsigned long           sector;                 /* sector of this row */
  30         int                     size;                   /* buffers size */
  31         int                     pd_idx;                 /* parity disk index */
  32         int                     nr_pending;             /* nr of pending cmds */
  33         unsigned long           state;                  /* state flags */
  34         int                     cmd;                    /* stripe cmd */
  35         int                     count;                  /* nr of waiters */
  36         int                     write_method;           /* reconstruct-write / read-modify-write */
  37         int                     phase;                  /* PHASE_BEGIN, ..., PHASE_COMPLETE */
  38         wait_queue_head_t       wait;                   /* processes waiting for this stripe */
  39 };
  40
  41 /*
  42  * Phase
  43  */
  44 #define PHASE_BEGIN             0
  45 #define PHASE_READ_OLD          1
  46 #define PHASE_WRITE             2
  47 #define PHASE_READ              3
  48 #define PHASE_COMPLETE          4
  49
  50 /*
  51  * Write method
  52  */
  53 #define METHOD_NONE             0
  54 #define RECONSTRUCT_WRITE       1
  55 #define READ_MODIFY_WRITE       2
  56
  57 /*
  58  * Stripe state
  59  */
  60 #define STRIPE_LOCKED           0
  61 #define STRIPE_ERROR            1
  62
  63 /*
  64  * Stripe commands
  65  */
  66 #define STRIPE_NONE             0
  67 #define STRIPE_WRITE            1
  68 #define STRIPE_READ             2
  69
  70 struct raid5_data {
  71         struct stripe_head      **stripe_hashtbl;
  72         struct md_dev           *mddev;
  73         struct md_thread        *thread, *resync_thread;
  74         struct disk_info        disks[MD_SB_DISKS];
  75         struct disk_info        *spare;
  76         int                     buffer_size;
  77         int                     chunk_size, level, algorithm;
  78         int                     raid_disks, working_disks, failed_disks;
  79         int                     sector_count;
  80         unsigned long           next_sector;
  81         atomic_t                nr_handle;
  82         struct stripe_head      *next_free_stripe;
  83         int                     nr_stripes;
  84         int                     resync_parity;
  85         int                     max_nr_stripes;
  86         int                     clock;
  87         int                     nr_hashed_stripes;
  88         int                     nr_locked_stripes;
  89         int                     nr_pending_stripes;
  90         int                     nr_cached_stripes;
  91
  92         /*
  93          * Free stripes pool
  94          */
  95         int                     nr_free_sh;
  96         struct stripe_head      *free_sh_list;
  97         wait_queue_head_t       wait_for_stripe;
  98 };
  99
 100 #endif
 101
 102 /*
 103  * Our supported algorithms
 104  */
 105 #define ALGORITHM_LEFT_ASYMMETRIC       0
 106 #define ALGORITHM_RIGHT_ASYMMETRIC      1
 107 #define ALGORITHM_LEFT_SYMMETRIC        2
 108 #define ALGORITHM_RIGHT_SYMMETRIC       3
 109
 110 #endif