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

[Christopher Covington]

Hi Oleg,

On 03/30/2015 11:35 AM, Oleg Nesterov wrote:
> Hi Christopher,
> 
> you know I am very-very new to criu/etc, not sure I understand you
> correctly...
> 
> On 03/30, 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?
> 
> How can unshare help? Perhaps you mean setns() + umount? But there can be
> other processes in the same mnt ns which need this mountpoint?

I usually dump very simple process trees in simple environments where this
sort of thing can work. It sounds like you have a more sophisticated process
tree and environment where it wouldn't work. (As far as I can tell, setns() is
for using a namespace that already exists, probably created by special flags
passed to clone() while unshare() creates a new namespace and uses it in one
call.)

> But the main question is why we can't add a cli option for that? And the
> patch is really simple after cleanups I sent. Hopefully I'll send it today
> if I have a bit of time.

I just wanted to check if it might be even simpler to do it outside of CRIU
than inside.

Chris

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