How to read and modify fields of a parent struct from a nested struct in Rust?

Question

even though I'm new to Rust, I already know that the following code block is totally incorrect, but I'm writing it anyway because I think it's clear what I'm trying to do:

#[derive(Debug)]
struct OData {
    of1: i32,
    of2: String,
    of3: IData,
};

#[derive(Debug)]
struct IData {
    if1: char,
    if2: String,
    if3: &mut OData,
}

I would like to be able to read and modify an instance of the OData struct from a struct nested in it. Can you help me? Thank you.