Re: [PATCH 1/3] autofs4 - fix device ioctl mount lookup

From: Ian Kent
Date: Tue Sep 03 2013 - 22:46:31 EST


On Tue, 2013-09-03 at 19:18 -0700, Linus Torvalds wrote:
> On Tue, Sep 3, 2013 at 7:00 PM, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > That aside, I'm really not happy with this kind of games; this stuff clearly
> > belongs in fs/namei.c where we can simply see the last component. Doing that
> > on the level of "let's scan the pathname for slashes, etc." is just plain
> > wrong. Let's step back for a minute here; what are you trying to do?
> > You have a pathname that should resolve to a mountpoint, without triggering
> > automount (or crossing into the mountpoint, for that matter) and you want
> > struct path for the bottom of that mount stack? Or is it something
> > completely different?
>
> Can we add a LOOKUP_NOAUTOMNT bit or something (not exposed to user
> space, only used for this particular kern_path() call). Then, if/when
> automount gets called recursively (through autofs4_lookup? Or is it
> just the autofs4_d_automount() interface?) it can just decide to not
> follow that last path.
>
> Hmm? I don't think we pass in the lookup-flags to d_automount, but
> that could be changed. Yes?

We don't need to.

Al is completely right, Jeff's umount path lookup patch will cover all
the needed cases, AFAICS.

That's a relief.

>
> Linus


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