[lxc-devel] [PATCH] lxc-checkpoint: add pre-checkpoint

[Ruslan Kuprieiev]

Hi Tycho,

On 06/30/2015 04:50 PM, Tycho Andersen wrote:
> Hey Ruslan,
>
> On Fri, Jun 26, 2015 at 11:24:32AM +0300, Ruslan Kuprieiev wrote:
>> Drop this one, please.
> I'm assuming you're probably going to send another version at some
> point, a question below.
>
>>> diff --git a/src/lxc/lxccontainer.h b/src/lxc/lxccontainer.h
>>> index d60e19a..1faded2 100644
>>> --- a/src/lxc/lxccontainer.h
>>> +++ b/src/lxc/lxccontainer.h
>>> @@ -773,7 +773,7 @@ struct lxc_container {
>>>   	 * \return \c true on success, else \c false.
>>>   	 * present at compile time).
>>>   	 */
>>> -	bool (*checkpoint)(struct lxc_container *c, char *directory, bool stop, bool verbose);
>>> +	bool (*checkpoint)(struct lxc_container *c, char *directory, char *prev_dir, bool stop, bool verbose);
> Here we're making an ABI change, and I'm not sure what the protocol in
> LXC for this (Stéphane or Serge can tell us I'm sure :). Whatever the
> case, we'll have to do some tap dancing here. It may (?) be worth
> turning this into an argument struct with version information to avoid
> this in the future, depending on how we solve this.

Neither am I happy about changing abi in such a way. That's one of the 
reasons
why I asked to drop this patch for now =).

But looks like there is no other way but to change abi, as current arguments
for do_checkpoint do not satisfy our needs, if we want teach lxc-checkpoint
to do anything more advanced than just plain dump.

Struct for options would be nice, I agree. But I actually thought about 
using
libcriu's options to set\get options without adding any additional mediator
structures. Though, It would require modifying libcriu to actually 
return void *
with options in it as well as adding criu_get-ers and fixing 
criu_set-ers to be
able to pass options struct as an argument.

> Anyway, I just thought I'd get the discussion started.
>
> Tycho
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