[CRIU] Sync TODO-s for mount.c work

[Oleg Nesterov]

On 04/22, Tycho Andersen wrote:
>
> On Wed, Apr 22, 2015 at 07:17:36PM +0200, Oleg Nesterov wrote:
> > > Anyway, yes, it
> > > could do MS_BIND with some sharing flags, I think we just haven't
> > > implemented that yet (this isn't an external mount, since it's bound
> > > within the namespace).
> >
> > _Yes_ thanks. So can't we teach "auto" to do this?
> >
> > OK, OK, perhaps we should not abuse --ext-mount-map option for that,
> > but this is minor.
>
> Yes, we can, except that the current autodetection doesn't work if the
> mounts are the "same" mount as you described in the other thread.

Yes, yes,

> We
> could have some other option that knows how to do this, though (or
> figure out how to detect the "same" mounts somehow and remove this
> restriction).

To me, "remove this restriction" makes much more sense. In fact, this
restriction looks like a bug to me.

Once again, in this particular case "auto" will wrongly treat all
mounts (except /) as a bind mount. This just means that you can never
use this option if the process inherits some mntpoint from parent ns.

Oleg.