[CRIU] [RFC] FSTYPE__UNSUPPORTED/AUTO && non-virtual filesystems

[Pavel Emelyanov]

On 03/30/2015 06:44 PM, Christopher Covington wrote:
> Hi Oleg,
> 
> On 03/28/2015 02:18 PM, Oleg Nesterov wrote:
> 
>> BUT. This makes me think again that we do want --ignore-this-mountpoint
>> option. Why not? And afaics trivial to implement. Of course, this will
>> be "use at your own risk" too.
> 
> How hard would it be to unshare the mount namespace, unmount the mountpoint
> you want to ignore, and then dump the checkpoint?

It will only work if there are no files opened/mapped on the mountpoint 
we want to ignore :) With the --enable-fs we just tell CRIU to auto-add
the desired filesystem into the "supported" list. E.g. tons of on-disk FS-s
don't require special handling, neither we can add all of the into sources.

For me it's like a plugin that eventually can turn into built-in feature.

> I recently was able to write a pretty simple C program to do this (and
> additionally pivot_root, umount specifying MNT_DETACH, and chroot or it
> probably could have stayed a shell script). (This little container let me
> debug Android init with strace and gdb.)

--Pavel