[PATCH] VFS buffer: calculate block-size correctly

From: Cong Meng
Date: Tue Aug 24 2010 - 03:40:07 EST


the invocation of __getblk(bdev, block, size) will cause kernel stall if
the @size parameter is not equal to the block size of the block device
saved in the inode struct.

submit_bh() has the similar problem.

this patch calculates the blocksize by the value i_blkbits saved in the
inode struct.

Signed-off-by: Cong Meng <mcpacino@xxxxxxxxx>
---
fs/buffer.c | 7 ++-----
1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/fs/buffer.c b/fs/buffer.c
index 3e7dca2..f7f9d33 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1051,10 +1051,7 @@ grow_buffers(struct block_device *bdev, sector_t block, int size)
pgoff_t index;
int sizebits;

- sizebits = -1;
- do {
- sizebits++;
- } while ((size << sizebits) < PAGE_SIZE);
+ sizebits = PAGE_CACHE_SHIFT - bdev->bd_inode->i_blkbits;

index = block >> sizebits;

@@ -2924,7 +2921,7 @@ int submit_bh(int rw, struct buffer_head * bh)
*/
bio = bio_alloc(GFP_NOIO, 1);

- bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+ bio->bi_sector = bh->b_blocknr << (bh->b_bdev->bd_inode->i_blkbits - 9);
bio->bi_bdev = bh->b_bdev;
bio->bi_io_vec[0].bv_page = bh->b_page;
bio->bi_io_vec[0].bv_len = bh->b_size;
--
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