For 32-bit architectures we need to cast first_block to u64 before
shifting it left.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reported-by: NJan Kara <jack@suse.cz>
Reviewed-by: NDave Chinner <dchinner@redhat.com>
Signed-off-by: NDave Chinner <david@fromorbit.com>