mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
34db0cd60f
RAID1 and RAID10 handle write requests by queuing them for handling by a separate thread. This is because when a write-intent-bitmap is active we might need to update the bitmap first, so it is good to queue a lot of writes, then do one big bitmap update for them all. However writeback request devices to appear to be congested after a while so it can make some guesstimate of throughput. The infinite queue defeats that (note that RAID5 has already has a finite queue so it doesn't suffer from this problem). So impose a limit on the number of pending write requests. By default it is 1024 which seems to be generally suitable. Make it configurable via module option just in case someone finds a regression. Signed-off-by: NeilBrown <neilb@suse.de>
138 lines
3.7 KiB
C
138 lines
3.7 KiB
C
#ifndef _RAID10_H
|
|
#define _RAID10_H
|
|
|
|
struct mirror_info {
|
|
struct md_rdev *rdev;
|
|
sector_t head_position;
|
|
int recovery_disabled; /* matches
|
|
* mddev->recovery_disabled
|
|
* when we shouldn't try
|
|
* recovering this device.
|
|
*/
|
|
};
|
|
|
|
struct r10conf {
|
|
struct mddev *mddev;
|
|
struct mirror_info *mirrors;
|
|
int raid_disks;
|
|
spinlock_t device_lock;
|
|
|
|
/* geometry */
|
|
int near_copies; /* number of copies laid out raid0 style */
|
|
int far_copies; /* number of copies laid 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;
|
|
int pending_count;
|
|
|
|
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 md_thread *thread;
|
|
};
|
|
|
|
/*
|
|
* 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 {
|
|
atomic_t remaining; /* 'have we finished' count,
|
|
* used from IRQ handlers
|
|
*/
|
|
sector_t sector; /* virtual sector number */
|
|
int sectors;
|
|
unsigned long state;
|
|
struct mddev *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)
|
|
/* When we successfully write to a known bad-block, we need to remove the
|
|
* bad-block marking which must be done from process context. So we record
|
|
* the success by setting devs[n].bio to IO_MADE_GOOD
|
|
*/
|
|
#define IO_MADE_GOOD ((struct bio *)2)
|
|
|
|
#define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
|
|
|
|
/* bits for r10bio.state */
|
|
#define R10BIO_Uptodate 0
|
|
#define R10BIO_IsSync 1
|
|
#define R10BIO_IsRecover 2
|
|
#define R10BIO_Degraded 3
|
|
/* Set ReadError on bios that experience a read error
|
|
* so that raid10d knows what to do with them.
|
|
*/
|
|
#define R10BIO_ReadError 4
|
|
/* If a write for this request means we can clear some
|
|
* known-bad-block records, we set this flag.
|
|
*/
|
|
#define R10BIO_MadeGood 5
|
|
#define R10BIO_WriteError 6
|
|
#endif
|