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Subject: Re: fanotify - overall design before I start sending patches
From: Eric Paris <eparis@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
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On Fri, 2009-08-07 at 18:36 +0200, Miklos Szeredi wrote:
> On Thu, 06 Aug 2009, Eric Paris wrote:
> > just work.  The whole reason for the timeout is because I don't trust
> > userspace not to get it wrong and I'd rather not lose my box because of
> > it.
> 
> IMO this has nothing to do with userspace(*) and everything to do with
> complexity.  Virus scanning is complex and any such code, whether
> runing in userspace or not, can easily screw up and freeze the system.

I agree, 'userspace' was not the best term.  Let me rephrase:

"The whole reason for the timeout is because I don't trust anything not
to get it wrong and I'd rather not lose my box because of it."

> The way to solve that is not to implement hacks on the kernel
> interface, but rather by separating the complex parts and implementing
> a simple watchdog layer on top of that, that makes sure things don't
> go wrong.

So you would argue that every fanotify listener implement their own
watchdog layer that may or may not be correct rather than do a single
watchdog layer for everyone?  And that's better?

-Eric