0a27ec96b6
raid10 needs to put up a barrier to new requests while it does resync or other background recovery. The code for this is currently open-coded, slighty obscure by its use of two waitqueues, and not documented. This patch gathers all the related code into 4 functions, and includes a comment which (hopefully) explains what is happening. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
103 lines
2.3 KiB
C
103 lines
2.3 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 copies; /* near_copies * far_copies.
|
|
* must be <= raid_disks
|
|
*/
|
|
sector_t stride; /* distance between far copies.
|
|
* This is size / far_copies
|
|
*/
|
|
|
|
int chunk_shift; /* shift from chunks to sectors */
|
|
sector_t chunk_mask;
|
|
|
|
struct list_head retry_list;
|
|
/* for use when syncing mirrors: */
|
|
|
|
spinlock_t resync_lock;
|
|
int nr_pending;
|
|
int nr_waiting;
|
|
int barrier;
|
|
sector_t next_resync;
|
|
|
|
wait_queue_head_t wait_barrier;
|
|
|
|
mempool_t *r10bio_pool;
|
|
mempool_t *r10buf_pool;
|
|
};
|
|
|
|
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];
|
|
};
|
|
|
|
/* bits for r10bio.state */
|
|
#define R10BIO_Uptodate 0
|
|
#define R10BIO_IsSync 1
|
|
#define R10BIO_IsRecover 2
|
|
#endif
|