[CRIU] [PATCH 0/3] devmap: Introduce ability to map block device when migraring filesystem

[Cyrill Gorcunov]

On Tue, Nov 24, 2015 at 01:12:17PM +0300, Cyrill Gorcunov wrote:
> It is been found that when we migrating to another machine with
> own ploop copy we can't restore inotify objects because the
> device ID of ploop has been changed and criu refuses to operate
> in such unknown environment.
> 
> Thus for migration we need some way to tell CRIU that changed
> device IDs are expected. Which is done via --device-map option
> (command line or RPC).
> 
> Note I've not yet tested this series in real life because I need
> to modify p.haul/vzmigrate as well.
> 
> Still please take a look, comments are highly appreciated. Maybe
> we should extend device-mapping from the beginning to consider
> type of devices, major/minor parts or device ranges.

Btw, I thought maybe it worth to extend --device-map option
syntax so for simple cases criu would handle device mapping
automatically so that we won't have to patch libvzctl|p.haul.

Say, former syntax

	--device-map a:b[,...]

extend with

	--device-map mount:root

so on restore the criu will figure out if --root option
is passed, and if so the criu fetch it's device number
and automatically maps all mount points which match the
root with new s_dev obtainer from runtime?