root/include/linux/raid/raid1.h

#ifndef _RAID1_H
#define _RAID1_H

#include <linux/raid/md.h>

typedef struct mirror_info mirror_info_t;

struct mirror_info {
        mdk_rdev_t      *rdev;
        sector_t        head_position;
};

/*
 * memory pools need a pointer to the mddev, so they can force an unplug
 * when memory is tight, and a count of the number of drives that the
 * pool was allocated for, so they know how much to allocate and free.
 * mddev->raid_disks cannot be used, as it can change while a pool is active
 * These two datums are stored in a kmalloced struct.
 */

struct pool_info {
        mddev_t *mddev;
        int     raid_disks;
};


typedef struct r1bio_s r1bio_t;

struct r1_private_data_s {
        mddev_t                 *mddev;
        mirror_info_t           *mirrors;
        int                     raid_disks;
        int                     last_used;
        sector_t                next_seq_sect;
        spinlock_t              device_lock;

        struct list_head        retry_list;
        /* queue pending writes and submit them on unplug */
        struct bio_list         pending_bio_list;
        /* queue of writes that have been unplugged */
        struct bio_list         flushing_bio_list;

        /* for use when syncing mirrors: */

        spinlock_t              resync_lock;
        int                     nr_pending;
        int                     nr_waiting;
        int                     nr_queued;
        int                     barrier;
        sector_t                next_resync;
        int                     fullsync;  /* set to 1 if a full sync is needed,
                                            * (fresh device added).
                                            * Cleared when a sync completes.
                                            */

        wait_queue_head_t       wait_barrier;

        struct pool_info        *poolinfo;

        struct page             *tmppage;

        mempool_t *r1bio_pool;
        mempool_t *r1buf_pool;
};

typedef struct r1_private_data_s conf_t;

/*
 * this is the only point in the RAID code where we violate
 * C type safety. mddev->private is an 'opaque' pointer.
 */
#define mddev_to_conf(mddev) ((conf_t *) mddev->private)

/*
 * this is our 'private' RAID1 bio.
 *
 * it contains information about what kind of IO operations were started
 * for this RAID1 operation, and about their status:
 */

struct r1bio_s {
        atomic_t                remaining; /* 'have we finished' count,
                                            * used from IRQ handlers
                                            */
        atomic_t                behind_remaining; /* number of write-behind ios remaining
                                                 * in this BehindIO request
                                                 */
        sector_t                sector;
        int                     sectors;
        unsigned long           state;
        mddev_t                 *mddev;
        /*
         * original bio going to /dev/mdx
         */
        struct bio              *master_bio;
        /*
         * if the IO is in READ direction, then this is where we read
         */
        int                     read_disk;

        struct list_head        retry_list;
        struct bitmap_update    *bitmap_update;
        /*
         * if the IO is in WRITE direction, then multiple bios are used.
         * We choose the number when they are allocated.
         */
        struct bio              *bios[0];
        /* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
};

/* when we get a read error on a read-only array, we redirect to another
 * device without failing the first device, or trying to over-write to
 * correct the read error.  To keep track of bad blocks on a per-bio
 * level, we store IO_BLOCKED in the appropriate 'bios' pointer
 */
#define IO_BLOCKED ((struct bio*)1)

/* bits for r1bio.state */
#define R1BIO_Uptodate  0
#define R1BIO_IsSync    1
#define R1BIO_Degraded  2
#define R1BIO_BehindIO  3
#define R1BIO_Barrier   4
#define R1BIO_BarrierRetry 5
/* For write-behind requests, we call bi_end_io when
 * the last non-write-behind device completes, providing
 * any write was successful.  Otherwise we call when
 * any write-behind write succeeds, otherwise we call
 * with failure when last write completes (and all failed).
 * Record that bi_end_io was called with this flag...
 */
#define R1BIO_Returned 6

#endif