fsverity: Wrap enable_verity in test code to retry on ETXTBSY

[jeckersb]

Signed-off-by: John Eckersberg [email protected]

[jeckersb]

Hm failures have nothing to do with this...

[jeckersb]

Somewhat confused why it's getting console-0.15.12 when we have 0.15.11 in Cargo.lock

[cgwalters]

I'm still not a big fan of fixing this only in the tests.

[cgwalters]

We can avoid this unreachable! with an explicit loop, something like this

fn enable_verity<H: FsVerityHashValue>(fd: impl AsFd) -> Result<(), EnableVerityError> {
    let mut attempt = 1;
    loop {
        match super::enable_verity::<H>(&fd) {
            Err(EnableVerityError::FileOpenedForWrite) if attempt < 3 => {
                std::thread::sleep(std::time::Duration::from_millis(1));
                attempt += 1;
            }
            other => return other,
        }
    }
}

But anyways I think it wouldn't really be too much more code to do the copy-based fallback right? And make it generic outside of the tests

[jeckersb]

I just now saw your comments in #106, before that I though we had agreed to leave enable_verity alone which is why I did this.