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    SubjectRe: [PATCH] v9fs: handle async processing of F_SETLK with FL_SLEEP flag
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    On 24.12.2021 10:31, Dominique Martinet wrote:
    > If that process is made asynchronous, we need a way to run more
    > 9p-specific code in that one's lm_grant callback, so we can proceed onto
    > the second step which is...
    >
    > - send the lock request to the 9p server and wait for its reply
    > (note that the current code is always synchronous here: even if you
    > request SETLK without the SLEEP flag you can be made to wait here.
    > I have work in the closest to make some requests asynchronous, so
    > locking could be made asynchronous when that lands, but my code
    > introduced a race somewhere I haven't had the time to fix so this
    > improvement will come later)
    >
    > What would you suggest with that?

    It isn't necessary to make request asynchronous,
    it's enough to avoid blocking locks.
    As far as I understand blocking does not happen for SETLK command,
    so it should be enough to chenge first part and call non-blocking
    posix_file_lock() instead of blocking locks_lock_file_wait().

    It would be great to make processing of 2nd part asynchronous too,
    but I think it looks like over-engineering, because we even are not
    100% sure that someone really uses this functionality.

    Thank you,
    Vasily Averin

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