Re: [Xen-devel] [PATCH v2 4/5] libxl: call hotplug scripts from libxl for vif

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2012-04-18 at 16:40 +0100, Roger Pau Monne wrote:
> On 18 Apr 2012, at 16:30, Ian Campbell wrote:
> 
> > On Wed, 2012-04-18 at 14:48 +0100, Roger Pau Monne wrote:
> >> On 18 Apr 2012, at 14:31, Ian Campbell wrote:
> >>
> >>>> Ok, I will add and extra parameter to libxl__initiate_device_remove
> >>>> that
> >>>> turns on or off the destruction of the front xenstore entries. We
> >>>> will
> >>>> first call it without removing the fronted, and if that fails we 
> >>>> will
> >>>> call libxl__initiate_device_remove from the callback this time
> >>>> forcing
> >>>> the removal of the frontend.
> >>>
> >>> If libxl__initiate_device_remove fails then you should be calling
> >>> libxl__initiate_device_destroy, I think, so no need for a param to
> >>> _remove?
> >>
> >> Not reallyâ That's how I think the removal path should be:
> >>
> >> 1- Wait for backend to turn to state 6 -----> if ok then execute
> >> hotplug, and remove front/backend
> >> 2- If timeout: nuke frontend and wait for backend state 6 -----> if 
> >> ok
> >> then execute hotplug and remove front/back
> >> 3- If timeout: nuke front/backend
> >
> > That could work, but what does doing step 2 buy you? Why not skip
> > straight to step 3?
> 
> hotplug scripts usually require the device to be on state 6 for them to 
> work, nuking the frontend forces the backend disconnection, and gets us 
> a state 6.

OK, that makes sense. You'd need to have two levels of timeout/callbacks
though?

Ian.




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