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    SubjectRe: [GIT PULL] Please pull NFS client bugfixes....
    On Fri, 2010-01-08 at 00:51 +0100, Andi Kleen wrote: 
    > > I'd like to see this fixed, but I do not want to jump onto a solution
    > > that changes the behaviour of mmap() w.r.t. revalidation. The current
    > > behaviour dates back at least to 2.3.x if not before.
    > So do you have a plan to fix it?

    Yes. I want to pursue Peter Zijlstra's patches, which split up the mmap
    function into a set of parts which require the mmap_sem, and other parts
    which don't, and that adds a filesystem callback that allows for
    revalidation to occur outside the mmap_sem.

    > I don't think it'll be possible to do drastic changes in the
    > VFS for 2.6.33, and it seems preserving the current semantics
    > would need that.
    > > That's why I'm working slowly on this.
    > Delaying a fix to after 2.6.33 is not an option imho.
    > It hits everyone with LOCKDEP enabled who uses mmap over NFS.
    > That's new in 2.6.33, previously LOCKDEP didn't diagnose this.
    > I'll keep using my patch, but I suppose once we're going more
    > towards a release you'll get more reports of this.

    Why should this particular issue require us to rush into a solution?
    This has been there for literally _years_, and I've never heard of a
    single incident in which a deadlock actually occurred. The only reason
    why we've noticed it at all is because lockdep has started to whine.

    I agree it should be fixed.

    I don't agree that it is urgent enough to warrant kneejerk reactions in
    2.6.33 which change long established behaviours that people are actually
    relying on.


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