Use a convenience variable instead of open-coding the inode fork.
This isn't really needed for now, but will become important when we
add the copy-on-write fork later.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>