kernel-ark/drivers/md/raid10.h
NeilBrown e93f68a1fc md: fix handling of array level takeover that re-arranges devices.
Most array level changes leave the list of devices largely unchanged,
possibly causing one at the end to become redundant.
However conversions between RAID0 and RAID10 need to renumber
all devices (except 0).

This renumbering is currently being done in the ->run method when the
new personality takes over.  However this is too late as the common
code in md.c might already have invalidated some of the devices if
they had a ->raid_disk number that appeared to high.

Moving it into the ->takeover method is too early as the array is
still active at that time and wrong ->raid_disk numbers could cause
confusion.

So add a ->new_raid_disk field to mdk_rdev_s and use it to communicate
the new raid_disk number.
Now the common code knows exactly which devices need to be renumbered,
and which can be invalidated, and can do it all at a convenient time
when the array is suspend.
It can also update some symlinks in sysfs which previously were not be
updated correctly.

Reported-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
2010-06-24 13:33:24 +10:00

123 lines
3.0 KiB
C

#ifndef _RAID10_H
#define _RAID10_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.
*/
sector_t dev_sectors; /* temp copy of mddev->dev_sectors */
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;
/* When taking over an array from a different personality, we store
* the new thread here until we fully activate the array.
*/
struct mdk_thread_s *thread;
};
typedef struct r10_private_data_s conf_t;
/*
* 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