android_kernel_motorola_sm6225/include/linux/raid/raid10.h
NeilBrown c93983bf51 [PATCH] md: support stripe/offset mode in raid10
The "industry standard" DDF format allows for a stripe/offset layout where
data is duplicated on different stripes.  e.g.

  A  B  C  D
  D  A  B  C
  E  F  G  H
  H  E  F  G

(columns are drives, rows are stripes, LETTERS are chunks of data).

This is similar to raid10's 'far' mode, but not quite the same.  So enhance
'far' mode with a 'far/offset' option which follows the layout of DDFs
stripe/offset.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 09:58:37 -07:00

124 lines
3 KiB
C

#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;
int working_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