root/include/linux/raid/raid10.h

#ifndef _RAID10_H
#define _RAID10_H

#include <linux/raid/md.h>

typedef struct mirror_info mirror_info_t;

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

typedef struct r10bio_s r10bio_t;

struct r10_private_data_s {
        mddev_t                 *mddev;
        mirror_info_t           *mirrors;
        int                     raid_disks;
        spinlock_t              device_lock;

        /* geometry */
        int                     near_copies;  /* number of copies layed out raid0 style */
        int                     far_copies;   /* number of copies layed out
                                               * at large strides across drives
                                               */
        int                     far_offset;   /* far_copies are offset by 1 stripe
                                               * instead of many
                                               */
        int                     copies;       /* near_copies * far_copies.
                                               * must be <= raid_disks
                                               */
        sector_t                stride;       /* distance between far copies.
                                               * This is size / far_copies unless
                                               * far_offset, in which case it is
                                               * 1 stripe.
                                               */

        int chunk_shift; /* shift from chunks to sectors */
        sector_t chunk_mask;

        struct list_head        retry_list;
        /* queue pending writes and submit them on unplug */
        struct bio_list         pending_bio_list;


        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;

        mempool_t *r10bio_pool;
        mempool_t *r10buf_pool;
        struct page             *tmppage;
};

typedef struct r10_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' RAID10 bio.
 *
 * it contains information about what kind of IO operations were started
 * for this RAID10 operation, and about their status:
 */

struct r10bio_s {
        atomic_t                remaining; /* 'have we finished' count,
                                            * used from IRQ handlers
                                            */
        sector_t                sector; /* virtual sector number */
        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_slot;

        struct list_head        retry_list;
        /*
         * if the IO is in WRITE direction, then multiple bios are used,
         * one for each copy.
         * When resyncing we also use one for each copy.
         * When reconstructing, we use 2 bios, one for read, one for write.
         * We choose the number when they are allocated.
         */
        struct {
                struct bio              *bio;
                sector_t addr;
                int devnum;
        } devs[0];
};

/* 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 r10bio.state */
#define R10BIO_Uptodate 0
#define R10BIO_IsSync   1
#define R10BIO_IsRecover 2
#define R10BIO_Degraded 3
#endif