From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sage Weil Subject: wip-proxy-write and (non-idempotent) client ops Date: Mon, 19 Jan 2015 08:50:47 -0800 (PST) Message-ID: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55420 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751401AbbASQut (ORCPT ); Mon, 19 Jan 2015 11:50:49 -0500 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: zhiqiang.wang@intel.com, sjust@redhat.com, ceph-devel@vger.kernel.org Consider: 1- primary rx client delete proxy delete to base pool 2- primary initiate promote (list-snaps, copy-from) 3- primary rx delete reply 4- primary tx client reply 5- socket failure drops client reply 6- primary rx promote completion (enoent), writes a whiteout 7- client resents delete 8- primary replies with ENOENT i.e., the problem seems to be that delete is not idempotent and we can't tell that the same client op is what triggered the delete. We could special case delete since that is where this is noticeable, but I think the bigger problem is that the op history that is used for dup op detection is not preserved across the cache and base tier. That is, this is another variation on this ticket: http://tracker.ceph.com/issues/8935 I have this sinking feeling we need to properly address that problem before we can do the write proxying... sage