[CRIU] v2: automatic detection of external bind mounts

[Tycho Andersen]

Hi Pavel,

On Thu, Apr 09, 2015 at 02:56:48PM -0600, Tycho Andersen wrote:
>
> Hmm, actually I found something wrong with this set. Please let me
> debug it.

So the problem is the fsroot_mounted() check; I knew it wasn't in there for a
reason :). I just tested the patch on the right (systemd) host and found the
problem. For e.g. pstore (but also kernel security and a few others), I have a
mountinfo entry in the container that looks like this:

90 83 0:23 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime master:11 - pstore pstore rw

and on the host:

29 17 0:23 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime shared:11 - pstore pstore rw

So, fsroot_mounted() is true, which means this mountpoint is never checked for
external sharing as it should be. I'm not sure what the right answer is here;
things work as I want them to if I leave the check out, but semantically the
check seems to make sense (at least in the case where there is no sharing).
Maybe that's the right answer, to only bail on fsroot_mounted() entries if
there is no external sharing?

Tycho