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| author | NeilBrown <neilb@cse.unsw.edu.au> | 2005-09-10 03:23:47 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-09-10 03:39:10 +0400 |
| commit | 4b6d287f627b5fb6a49f78f9e81649ff98c62bb7 (patch) | |
| tree | 7b6cbc6a997e25a7fb6185da7129e539c4ffda8b /include/linux/raid/bitmap.h | |
| parent | 8ddf9efe6708f3674f0ddfeb6425fd27bea109a2 (diff) | |
| download | linux-4b6d287f627b5fb6a49f78f9e81649ff98c62bb7.tar.xz | |
[PATCH] md: add write-behind support for md/raid1
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>
Diffstat (limited to 'include/linux/raid/bitmap.h')
| -rw-r--r-- | include/linux/raid/bitmap.h | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h index 4bf1659f8aa8..9de99198caf1 100644 --- a/include/linux/raid/bitmap.h +++ b/include/linux/raid/bitmap.h @@ -7,7 +7,7 @@ #define BITMAP_H 1 #define BITMAP_MAJOR 3 -#define BITMAP_MINOR 38 +#define BITMAP_MINOR 39 /* * in-memory bitmap: @@ -147,8 +147,9 @@ typedef struct bitmap_super_s { __u32 state; /* 48 bitmap state information */ __u32 chunksize; /* 52 the bitmap chunk size in bytes */ __u32 daemon_sleep; /* 56 seconds between disk flushes */ + __u32 write_behind; /* 60 number of outstanding write-behind writes */ - __u8 pad[256 - 60]; /* set to zero */ + __u8 pad[256 - 64]; /* set to zero */ } bitmap_super_t; /* notes: @@ -226,6 +227,9 @@ struct bitmap { unsigned long flags; + unsigned long max_write_behind; /* write-behind mode */ + atomic_t behind_writes; + /* * the bitmap daemon - periodically wakes up and sweeps the bitmap * file, cleaning up bits and flushing out pages to disk as necessary @@ -260,9 +264,10 @@ int bitmap_setallbits(struct bitmap *bitmap); void bitmap_write_all(struct bitmap *bitmap); /* these are exported */ -int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors); -void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, - int success); +int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, + unsigned long sectors, int behind); +void bitmap_endwrite(struct bitmap *bitmap, sector_t offset, + unsigned long sectors, int success, int behind); int bitmap_start_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int degraded); void bitmap_end_sync(struct bitmap *bitmap, sector_t offset, int *blocks, int aborted); void bitmap_close_sync(struct bitmap *bitmap); |