From mboxrd@z Thu Jan  1 00:00:00 1970
From: Greg Kurz <gkurz-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
Subject: Re: [RFC][PATCH 1/2] Track in-kernel when we expect
	checkpoint/restart to work
Date: Fri, 10 Oct 2008 10:47:01 +0200
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To: Daniel Lezcano <dlezcano-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>, arnd-r2nGTMty4D4@public.gmane.org, Dave Hansen <dave-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
List-Id: containers.vger.kernel.org

On Fri, 2008-10-10 at 10:37 +0200, Daniel Lezcano wrote:
> I think implementing the reverse operation will be a nightmare, IMHO it 
> is safe to say we deny checkpointing for the process life-cycle either 
> if the created resource was destroyed before we initiate the checkpoint.
> 
> For example, you create a socket, the process becomes uncheckpointable, 
> you close (via sys_close) the socket, you have to track this close to be 
> related to the socket which made the process uncheckpointable in order 
> to make the operation reversible.
> 
> Let's imagine you implement this reverse operation anyway, you have a 
> process which creates a TCP connection, writes data and close the socket 
> (so you are again checkpointable), but in the namespace there is the 
> orphan socket which is not checkpointable yet and you missed this case.

That's exactly what I wanted to read... Tracking only is inherently
flawed. The valid way IMHO implies checks at checkpoint time.

-- 
Gregory Kurz                                     gkurz-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org
Software Engineer @ IBM/Meiosys                  http://www.ibm.com
Tel +33 (0)534 638 479                           Fax +33 (0)561 400 420

"Anarchy is about taking complete responsibility for yourself."
        Alan Moore.