4b6d287f62
If a device is flagged 'WriteMostly' and the array has a bitmap, and the bitmap superblock indicates that write_behind is allowed, then write_behind is enabled for WriteMostly devices. Write requests will be acknowledges as complete to the caller (via b_end_io) when all non-WriteMostly devices have completed the write, but will not be cleared from the bitmap until all devices complete. This requires memory allocation to make a local copy of the data being written. If there is insufficient memory, then we fall-back on normal write semantics. Signed-Off-By: Paul Clements <paul.clements@steeleye.com> Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
124 lines
3.0 KiB
C
124 lines
3.0 KiB
C
#ifndef _RAID1_H
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#define _RAID1_H
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#include <linux/raid/md.h>
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typedef struct mirror_info mirror_info_t;
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struct mirror_info {
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mdk_rdev_t *rdev;
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sector_t head_position;
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};
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/*
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* memory pools need a pointer to the mddev, so they can force an unplug
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* when memory is tight, and a count of the number of drives that the
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* pool was allocated for, so they know how much to allocate and free.
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* mddev->raid_disks cannot be used, as it can change while a pool is active
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* These two datums are stored in a kmalloced struct.
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*/
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struct pool_info {
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mddev_t *mddev;
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int raid_disks;
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};
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typedef struct r1bio_s r1bio_t;
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struct r1_private_data_s {
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mddev_t *mddev;
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mirror_info_t *mirrors;
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int raid_disks;
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int working_disks;
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int last_used;
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sector_t next_seq_sect;
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spinlock_t device_lock;
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struct list_head retry_list;
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/* queue pending writes and submit them on unplug */
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struct bio_list pending_bio_list;
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/* queue of writes that have been unplugged */
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struct bio_list flushing_bio_list;
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/* for use when syncing mirrors: */
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spinlock_t resync_lock;
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int nr_pending;
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int barrier;
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sector_t next_resync;
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int fullsync; /* set to 1 if a full sync is needed,
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* (fresh device added).
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* Cleared when a sync completes.
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*/
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wait_queue_head_t wait_idle;
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wait_queue_head_t wait_resume;
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struct pool_info *poolinfo;
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mempool_t *r1bio_pool;
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mempool_t *r1buf_pool;
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};
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typedef struct r1_private_data_s conf_t;
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/*
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* this is the only point in the RAID code where we violate
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* C type safety. mddev->private is an 'opaque' pointer.
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*/
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#define mddev_to_conf(mddev) ((conf_t *) mddev->private)
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/*
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* this is our 'private' RAID1 bio.
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*
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* it contains information about what kind of IO operations were started
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* for this RAID1 operation, and about their status:
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*/
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struct r1bio_s {
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atomic_t remaining; /* 'have we finished' count,
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* used from IRQ handlers
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*/
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atomic_t behind_remaining; /* number of write-behind ios remaining
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* in this BehindIO request
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*/
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sector_t sector;
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int sectors;
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unsigned long state;
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mddev_t *mddev;
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/*
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* original bio going to /dev/mdx
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*/
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struct bio *master_bio;
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/*
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* if the IO is in READ direction, then this is where we read
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*/
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int read_disk;
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struct list_head retry_list;
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struct bitmap_update *bitmap_update;
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/*
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* if the IO is in WRITE direction, then multiple bios are used.
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* We choose the number when they are allocated.
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*/
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struct bio *bios[0];
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/* DO NOT PUT ANY NEW FIELDS HERE - bios array is contiguously alloced*/
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};
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/* bits for r1bio.state */
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#define R1BIO_Uptodate 0
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#define R1BIO_IsSync 1
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#define R1BIO_Degraded 2
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#define R1BIO_BehindIO 3
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/* For write-behind requests, we call bi_end_io when
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* the last non-write-behind device completes, providing
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* any write was successful. Otherwise we call when
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* any write-behind write succeeds, otherwise we call
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* with failure when last write completes (and all failed).
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* Record that bi_end_io was called with this flag...
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*/
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#define R1BIO_Returned 4
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#endif
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