[CRIU] [PATCH] mnt: add support for external shared mounts

[Pavel Emelyanov]

On 04/03/2015 07:20 PM, Tycho Andersen wrote:
> Hi Andrey,
> 
> On Fri, Apr 03, 2015 at 07:00:43PM +0300, Andrew Vagin wrote:
>> On Thu, Apr 02, 2015 at 08:22:33PM +0000, Tycho Andersen wrote:
>>> Add support for external shared mounts via the --enable-external-masters flag.
>>> This flag assumes that the mount is visible to criu via /proc/self/mountinfo
>>> and that it will be present at the same location on restore. No attempt to dump
>>> or restore the content is made; the external master is bind mounted into the
>>> mount ns and whatever is there is what the container sees.
>>
>> I need time to think about the idea. At the first glance it should work.
>>
>> But we (I and Pavel) are not sure that we understand what you do:).
>>
>> Could you show /proc/PID/mountinfo for a container? Why can you not use
>> external mounts?
> 
> Because criu dies with "couldn't find sharing" before the external
> mount map is consulted. I could use ext-mount-map, but we'd still need
> some patch to skip this check, and since we can resolve these
> automatically anyway it seems like we should just do that instead.

Ouch, so the slavery is set up for external mount points? I've missed that, sorry :(
But taking into account my new insight :) doesn't the patch falls logically into
two pieces -- the first is auto-assignments for ext-mount-map-s and the second --
enabling for slave external bind mounts?

-- Pavel