xfs: fix units conversion error in xfs_bmap_del_extent_delay

commit ddd98076d5c075c8a6c49d9e6e8ee12844137f23 upstream.

The unit conversions in this function do not make sense.  First we
convert a block count to bytes, then divide that bytes value by
rextsize, which is in blocks, to get an rt extent count.  You can't
divide bytes by blocks to get a (possibly multiblock) extent value.

Fortunately nobody uses delalloc on the rt volume so this hasn't
mattered.

Fixes: fa5c836ca8eb5 ("xfs: refactor xfs_bunmapi_cow")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 26bfa34..617cc7e 100644 (file)
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4827,7 +4827,7 @@ xfs_bmap_del_extent_delay(
        ASSERT(got_endoff >= del_endoff);
 
        if (isrt) {
-               uint64_t rtexts = XFS_FSB_TO_B(mp, del->br_blockcount);
+               uint64_t        rtexts = del->br_blockcount;
 
                do_div(rtexts, mp->m_sb.sb_rextsize);
                xfs_mod_frextents(mp, rtexts);