[CRIU] CRIU unable to see external mounts while restore

[Pavel Emelyanov]

On 02/17/2015 09:54 PM, beproject criu wrote:
> Hi,
> I am trying to dump lxc container where container has external mount on /dev.
> I have used --ext-mount-map /dev:dev while dumping. below is the full command used for dump.
> 
> #criu dump --root /usr/local/lib/lxc/rootfs/root --evasive-devices \
> --tcp-established --ext-mount-map /dev:dev --file-locks -n net -n mnt \
> -n ipc -n pid -vvvvvvvv -D data -o dump.log -t <pid>

Can you check the mountpoints image file contents with criu show -f?

> I am trying to restore container using the following command,
> #criu restore --root /home/nyc/A/rootfs/ --ext-mount-map dev:/dev -d -vvv -o restore.log

The -v4 produces more informative logs.

> But, while restore it is not able to see the external mounts.
> I added the following message in mount.c=>validate_mounts,line no. 610.
> 
>  if (!strncmp(m->mountpoint, "./dev", 5))
>     pr_info("%s mount on %s\n",m->fstype->name, m->mountpoint);
> 
> This printed a line "unsupported mount on ./dev" in restore.log

Did restore fail? With what message? Can you show the full restore.log file?

> What might be the reason for this?
> Why is criu not able able to see external mounts?

If there's a message "Mounpoint ... will have root from ..." in logs,
then the external mount was successfully resolved.

Thanks,
Pavel