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do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned

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The code currently uses sdio->blkbits to compute the number of blocks to
be cleaned. However sdio->blkbits is derived from the logical block size
of the underlying block device (Refer to the definition of
do_blockdev_direct_IO()). Due to this, generic/299 test would rarely
fail when executed on an ext4 filesystem with 64k as the block size and
when using a virtio based disk (having 512 byte as the logical block
size) inside a kvm guest.

This commit fixes the bug by using inode->i_blkbits to compute the
number of blocks to be cleaned.

Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Fixed up by Jeff Moyer to only use/evaluate inode->i_blkbits once,
to avoid issues with block size changes with IO in flight.

Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Chandan Rajendra 2017-01-10 13:29:54 -07:00 committed by Jens Axboe
parent a121103c92
commit dd545b52a3
1 changed files with 2 additions and 1 deletions
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3
fs/direct-io.c
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@ -906,6 +906,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
struct buffer_head *map_bh)
{
const unsigned blkbits = sdio->blkbits;
const unsigned i_blkbits = blkbits + sdio->blkfactor;
int ret = 0;
while (sdio->block_in_file < sdio->final_block_in_request) {
@ -949,7 +950,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
clean_bdev_aliases(
map_bh->b_bdev,
map_bh->b_blocknr,
map_bh->b_size >> blkbits);
map_bh->b_size >> i_blkbits);
}
if (!sdio->blkfactor)