raid5.h

GNU Hurd 源代码

#ifndef _RAID5_H
#define _RAID5_H

#ifdef __KERNEL__
#include <linux/md.h>
#include <asm/atomic.h>

struct disk_info {
	kdev_t	dev;
	int	operational;
	int	number;
	int	raid_disk;
	int	write_only;
	int	spare;
};

struct stripe_head {
	struct stripe_head	*hash_next, **hash_pprev; /* hash pointers */
	struct stripe_head	*free_next;		/* pool of free sh's */
	struct buffer_head	*buffer_pool;		/* pool of free buffers */
	struct buffer_head	*bh_pool;		/* pool of free bh's */
	struct raid5_data	*raid_conf;
	struct buffer_head	*bh_old[MD_SB_DISKS];	/* disk image */
	struct buffer_head	*bh_new[MD_SB_DISKS];	/* buffers of the MD device (present in buffer cache) */
	struct buffer_head	*bh_copy[MD_SB_DISKS];	/* copy on write of bh_new (bh_new can change from under us) */
	struct buffer_head	*bh_req[MD_SB_DISKS];	/* copy of bh_new (only the buffer heads), queued to the lower levels */
	int			cmd_new[MD_SB_DISKS];	/* READ/WRITE for new */
	int			new[MD_SB_DISKS];	/* buffer added since the last handle_stripe() */
	unsigned long		sector;			/* sector of this row */
	int			size;			/* buffers size */
	int			pd_idx;			/* parity disk index */
	int			nr_pending;		/* nr of pending cmds */
	unsigned long		state;			/* state flags */
	int			cmd;			/* stripe cmd */
	int			count;			/* nr of waiters */
	int			write_method;		/* reconstruct-write / read-modify-write */
	int			phase;			/* PHASE_BEGIN, ..., PHASE_COMPLETE */
	struct wait_queue	*wait;			/* processes waiting for this stripe */
};

/*
 * Phase
 */
#define PHASE_BEGIN		0
#define PHASE_READ_OLD		1
#define PHASE_WRITE		2
#define PHASE_READ		3
#define PHASE_COMPLETE		4

/*
 * Write method
 */
#define METHOD_NONE		0
#define RECONSTRUCT_WRITE	1
#define READ_MODIFY_WRITE	2

/*
 * Stripe state
 */
#define STRIPE_LOCKED		0
#define STRIPE_ERROR		1

/*
 * Stripe commands
 */
#define STRIPE_NONE		0
#define	STRIPE_WRITE		1
#define STRIPE_READ		2

struct raid5_data {
	struct stripe_head	**stripe_hashtbl;
	struct md_dev		*mddev;
	struct md_thread	*thread, *resync_thread;
	struct disk_info	disks[MD_SB_DISKS];
	struct disk_info	*spare;
	int			buffer_size;
	int			chunk_size, level, algorithm;
	int			raid_disks, working_disks, failed_disks;
	int			sector_count;
	unsigned long		next_sector;
	atomic_t		nr_handle;
	struct stripe_head	*next_free_stripe;
	int			nr_stripes;
	int			resync_parity;
	int			max_nr_stripes;
	int			clock;
	int			nr_hashed_stripes;
	int			nr_locked_stripes;
	int			nr_pending_stripes;
	int			nr_cached_stripes;

	/*
	 * Free stripes pool
	 */
	int			nr_free_sh;
	struct stripe_head	*free_sh_list;
	struct wait_queue	*wait_for_stripe;
};

#endif

/*
 * Our supported algorithms
 */
#define ALGORITHM_LEFT_ASYMMETRIC	0
#define ALGORITHM_RIGHT_ASYMMETRIC	1
#define ALGORITHM_LEFT_SYMMETRIC	2
#define ALGORITHM_RIGHT_SYMMETRIC	3

#endif