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md/bitmap: fix calculation of 'chunks' - missing shift.

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commit 61a0d80c "md/bitmap: discard CHUNK_BLOCK_SHIFT macro"
replaced CHUNK_BLOCK_RATIO() by the same text that was
replacing CHUNK_BLOCK_SHIFT() - which is clearly wrong.

The result is that 'chunks' is often too small by 1,
which can sometimes result in a crash (not sure how).

So use the correct replacement, and get rid of CHUNK_BLOCK_RATIO
which is no longe used.

Reported-by: Karl Newman <siliconfiend@gmail.com>
Tested-by: Karl Newman <siliconfiend@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
This commit is contained in:
NeilBrown 2012-05-04 17:03:18 +10:00
parent 69964ea4c7
commit b16b1b6cd0
2 changed files with 1 additions and 5 deletions
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3
drivers/md/bitmap.c
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@ -1727,8 +1727,7 @@ int bitmap_create(struct mddev *mddev)
bitmap->chunkshift = (ffz(~mddev->bitmap_info.chunksize)
- BITMAP_BLOCK_SHIFT);
/* now that chunksize and chunkshift are set, we can use these macros */
chunks = (blocks + bitmap->chunkshift - 1) >>
chunks = (blocks + (1 << bitmap->chunkshift) - 1) >>
bitmap->chunkshift;
pages = (chunks + PAGE_COUNTER_RATIO - 1) / PAGE_COUNTER_RATIO;

3
drivers/md/bitmap.h
View file

@ -101,9 +101,6 @@ typedef __u16 bitmap_counter_t;
#define BITMAP_BLOCK_SHIFT 9
/* how many blocks per chunk? (this is variable) */
#define CHUNK_BLOCK_RATIO(bitmap) ((bitmap)->mddev->bitmap_info.chunksize >> BITMAP_BLOCK_SHIFT)
#endif
/*