[lxc-devel] [RFC PATCH 00/11] Add support for devtmpfs in user namespaces

[Greg Kroah-Hartman]

On Fri, May 16, 2014 at 01:49:59AM +0000, Serge Hallyn wrote:
> > I think having to pick and choose what device nodes you want in a
> > container is a good thing.  Becides, you would have to do the same thing
> > in the kernel anyway, what's wrong with userspace making the decision
> > here, especially as it knows exactly what it wants to do much more so
> > than the kernel ever can.
> 
> For 'real' devices that sounds sensible.  The thing about loop devices
> is that we simply want to allow a container to say "give me a loop
> device to use" and have it receive a unique loop device (or 3), without
> having to pre-assign them.  I think that would be cleaner to do using
> a pseudofs and loop-control device, rather than having to have a
> daemon in userspace on the host farming those out in response to
> some, I don't know, dbus request?

I agree that loop devices would be nice to have in a container, and that
the existing loop interface doesn't really lend itself to that.  So
create a new type of thing that acts like a loop device in a container.
But don't try to mess with the whole driver core just for a single type
of device.

greg k-h