Re: [PATCH 2/3] fs: namei: Allow follow_down() to uncover auto mounts

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Jeff Layton" <jlayton@xxxxxxxxxx>
> What happens when CROSSMOUNT isn't enabled and someone tries to stroll
> into an automount point? I'm guessing the automount happens but the
> export is denied? 

Exactly.

On the other hand, why should knfsd not trigger automounts?
Almost any userspace interaction would also do so.

> It seems like LOOKUP_AUTOMOUNT ought to be conditional
> on the parent export having CROSSMOUNT set.
> 
> There's also another caller of follow_down too, the UNIX98 pty code.
> This may be harmless for it, but it'd be best not to perturb that if we
> can help it.
> 
> Maybe follow_down can grow a lookupflags argument?

So, in nfsd_cross_mnt() the follow_down() helper should use LOOKUP_AUTOMOUNT only
if exp->ex_flags & NFSEXP_CROSSMOUNT is true?
Sounds sane, thanks for the pointer.

Thanks,
//richard