ocfs2_dlmfs: Fix math error when reading LVB.

When asked for a partial read of the LVB in a dlmfs file, we can
accidentally calculate a negative count.

Reported-by: Dan Carpenter <error27@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
1 file changed