[Devel] [PATCH rh7] ve/devpts: Force devpts mounting to use @newinstance inside VE

[Cyrill Gorcunov]

On Mon, Jul 20, 2015 at 03:19:32PM +0300, Andrew Vagin wrote:
> On Fri, Jul 17, 2015 at 06:33:48PM +0300, Cyrill Gorcunov wrote:
> > Modern systemd based containers (such as fedora-21, centos-7) already
> > mounting initial devpts filesystem with @newinstance option but it
> > turned out that ubuntu-14 lts doesn't, which makes restore procedure
> > to fail because we're using get_exec_env as a namespace mark and the
> > kernel mounts new superblock for container internally. This is done
> > to isolate devpts between containers but criu sees it as filesystems
> > mounted with @newinstance option. Thus lets always mount devpts
> > inside containers with @newinstance instead, this should not hurt
> > anyhow ecxept we need precious testing of docker running inside
> > container.
> 
> "mount -t devpts XXX XXX" must return the same instance each time. With
> your patch it returns a new instance. IMHO this is unexpected behaviour
> and it's wrong.

It does, on the node. The patch changes behaviour in container only.
Do we really need additional devpts inside containers?