[sheepdog] [PATCH v2 2/7] sheep: make gateway to retry when received SD_RES_OLD_NODE_VER

[levin li]

On 05/23/2012 11:08 PM, Christoph Hellwig wrote:
> Oh ok - this patch changes things enough that we can't do what I
> proposed in the previous mail.
> 
>> +		switch (req->rp.result) {
>> +		case SD_RES_OLD_NODE_VER:
>> +			/* retry as gateway. */
>> +			req->rq.epoch = sys->epoch;
>> +			put_vnode_info(req->vnodes);
>> +			req->vnodes = get_vnode_info();
>> +			setup_access_to_local_objects(req);
> 
> Can you add a helper to share this code with gateway_op_done?  Having
> this in a properly named helper also helps with self-documenting the
> code.

I didn't say gateway_op_done in your code, do you mean to split gateway_op_done
from io_op_done ?

> 
>> +		case SD_RES_NEW_NODE_VER:
>> +			list_del(&req->request_list);
>> +			list_add_tail(&req->request_list, &sys->request_queue);
>> +			process_request_event_queues();
>> +			break;
>> +		default:
> 
> We're probably still better off calling process_request_event_queues
> once after the loop instead of possibly starting to queue and complete
> I/O from inside the loop.  resume_pending_requests already does that
> variant, although I think it has a bug because it only checks for a
> non-emptry request_queue but not the event queue.

Calling process_request_event_queue outside the loop seems good to me,
but I don't think it's necessary to call resume_pending_requests instead of
process_request_event_queue, resume_pending_requests move the requests in
req_wait_for_obj_list into the sys->request_queue, I don't think it's always
necessary.

thanks,

levin