Re: [RFC PATCH 0/5] Second attempt at contained helper execution

From: J. Bruce Fields
Date: Thu Jan 15 2015 - 11:27:50 EST


On Thu, Jan 15, 2015 at 08:26:12AM +0800, Ian Kent wrote:
> On Wed, 2015-01-14 at 17:10 -0500, J. Bruce Fields wrote:
> > > On Wed, Jan 14, 2015 at 05:32:22PM +0800, Ian Kent wrote:
> > > > There are other difficulties to tackle as well, such as how to decide
> > > > if contained helper execution is needed. For example, if a mount has
> > > > been propagated to a container or bound into the container tree (such
> > > > as with the --volume option of "docker run") the root init namespace
> > > > may need to be used and not the container namespace.
> >
> > I think you have to go through each of the existing upcall examples and
> > decide what's needed for each.
> >
> > At least for the nfsv4 idmapper I would've thought the namespace the
> > mount was done in would be the right choice, hence my previous question.
>
> Probably but you don't necessarily know what namespace the mount was
> done in. It may have been propagated from another namespace or (although
> I don't think it works yet) bound from another container using the
> volumes-from docker option.

Name-id mappings should be associated with the superblock, I guess--so
don't you store a pointer to the right thing there?

--b.

>
> At least I believe that's a problem and I agree that, once a suitable
> method of running helpers is found each case will need to be looked at.
>
> Ian
>
>
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