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    SubjectRe: nfs: infinite loop in fcntl(F_SETLKW)
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    > > > > OK. So the correct fix here should really be applied to fcntl_setlk().
    > > > > There is absolutely no reason why we should be looping at all if the
    > > > > filesystem has a ->lock() method.
    > > > >
    > > > > In fact, this looping behaviour was introduced recently in commit
    > > > > 7723ec9777d9832849b76475b1a21a2872a40d20.
    > > >
    > > > Apologies, that was indeed a behavioral change introduced in a commit
    > > > that claimed just to be shuffling code around.
    > >
    > > Yeah, that patch looks totally wrong. It's not generally a good idea
    > > to do a loop where the exit condition depends on something you don't
    > > control. And error values from filesystem methods are typically like
    > > that. For example with fuse, the error code could come from an
    > > unprivileged userspace process.
    > >
    > > I didn't realize this aspect of the bug previously, because I
    > > concentrated on the lockd inconsistency.
    >
    > So, does this patch on its own fix the problem you saw?

    Yes. With the patch applied, the test program returns "lockf:
    Resource temporarily unavailable" instead of hanging.

    Thanks,
    Miklos


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