user-cr: Extra unshare() calls ?

[Serge E. Hallyn]

Quoting Sukadev Bhattiprolu (sukadev at linux.vnet.ibm.com):
> 
> Came across this while testing LXC.
> 
> 
> 1. Does ckpt_remount_proc() need to unshare() ? Or can we have the
>    clone() that calls __ckpt_coordinator() clone with CLONE_NEWNS|CLONE_FS
>    instead ?
> 
>    The problem with the unshare() in ckpt_remount_proc() is that it
>    creates an extra level in cgroup hierarchy (see below) after restart.
>    So applications expecting the cgroup hierarchy before chckpoint will
>    be surprised.
> 
> 2. When --mount-pty (or --mntns) is specified, do we need to unshare() 
>    in the parent process ? Considering only the full-container restart
>    for now (ignore self-restart and subtree restart), can we just
>    specify (CLONE_NEWNS|CLONE_FS) at the time of creating the first
>    restarted process ?

And then move remounting of devpts into ckpt_remount_proc() called
from __ckpt_coordinator() as well?

-serge