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Subject: Re: [PATCH v12 10/12] namei: aggressively check for nd->root escape on ".." resolution
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Date:   Wed, 04 Sep 2019 23:31:16 +0100
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Linus Torvalds <torvalds@linux-foundation.org> wrote:

> > Hinting to userspace to do a retry (with -EAGAIN as you mention in your
> > other mail) wouldn't be a bad thing at all, though you'd almost
> > certainly get quite a few spurious -EAGAINs -- &{mount,rename}_lock are
> > global for the entire machine, after all.
> 
> I'd hope that we have some future (possibly very long-term)
> alternative that is not quite system-global, but yes, right now they
> are.

It ought to be reasonably easy to make them per-sb at least, I think.  We
don't allow cross-super rename, right?

David