[SCM] Samba Shared Repository - branch master updated

[Michael Adam]

Hi Volker,

first of all, thanks for your comments and please
excuse the irritation. The patch seems to have been
pushed prematurely. Currently an additional patch is
being worked on and tested which removes all the
pthread and eventfd calls and replaces the notification
mechanism by a simple pipe, as Ira has indicated.

That will remove the immediate concerns about pthread
calls being used in the module, but still the
calls to glfs_pread_async() are there, so the more sublte
concern remains how the gluster gfapi library uses threads
(and whether it can be avoided). I am currently looking
into the code, trying to understand it, but I'm sure we
will also get an update and information from Poornima,
the patch author.

Stay tuned and thanks - Michael

On 2014-12-18 at 12:56 +0100, Volker Lendecke wrote:
> On Wed, Dec 17, 2014 at 04:36:03PM +0100, Günther Deschner wrote:
> > +	/*
> > +	 * Store the reqs that needs to be completed by calling
> > +	 * tevent_req_done(). tevent_req_done() cannot be called
> > +	 * here, as it is not designed to be executed in the
> > +	 * multithread environment, tevent_req_done() should be
> > +	 * executed from the smbd main thread.
> > +	 */
> > +	pthread_mutex_lock (&lock_req_list);
> > +	{
> > +		for (i = 0 ; i < aio_pending_size ; i++) {
> > +			if(!req_producer_list[i]) {
> > +				req_producer_list[i] = req;
> > +				req_counter = req_counter + 1;
> > +				break;
> > +			}
> > +		}
> > +	}
> > +	pthread_mutex_unlock (&lock_req_list);
> 
> One thing that just struck me (and that it took so long to
> figure this out is a bad sign to me): Wherever there's a
> pthread_mutex_lock call there needs to be the corresponding
> pthread_atfork handler. smbd expects to be able to fork
> properly, I know of an internal VFS module that does this.
> And we have a module vfs_aio_fork that might be applied to
> a different share. So we need to maintain forkability. With
> the phreadpool approach I've tried to take care of this (if
> that's not complete, please tell me!).
> 
> As I've not found documentation about the gluster aio
> interface, can we get confirmation from the developers of
> the gluster library that this is being taken care of?
> 
> Thanks!
> 
> Volker
> 
> -- 
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