From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262004AbUBWWP1 (ORCPT ); Mon, 23 Feb 2004 17:15:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262046AbUBWWP1 (ORCPT ); Mon, 23 Feb 2004 17:15:27 -0500 Received: from e33.co.us.ibm.com ([32.97.110.131]:50383 "EHLO e33.co.us.ibm.com") by vger.kernel.org with ESMTP id S262004AbUBWWPW (ORCPT ); Mon, 23 Feb 2004 17:15:22 -0500 Message-ID: <403A79E0.6080609@us.ibm.com> Date: Mon, 23 Feb 2004 14:08:32 -0800 From: Mike Christie User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.6) Gecko/20040113 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Joe Thornber CC: Andrew Morton , Linux Mailing List Subject: Re: [Patch 1/6] dm: endio method References: <20040220153145.GN27549@reti> <20040220153403.GO27549@reti> <40372BCE.7090708@us.ibm.com> <20040223100512.GB943@reti> In-Reply-To: <20040223100512.GB943@reti> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hey Joe, Joe Thornber wrote: > Mike, > > On Sat, Feb 21, 2004 at 01:58:38AM -0800, Mike Christie wrote: > >>Saving and restoring bi_bdev is going to break multipath. > > > Yes, we'll have to fall back to plan A and use the map_context pointer > to hold the path being used (attached patch for illustration only). I > had been hoping we could keep the map_context unused so that we could > allow the path selectors to use it. I should have spotted this. > > I'll also move the failed bio remap back to mpath_end_io(), so that > the context can be reused there (it moved to the daemon when we were > trying to do path testing in the kernel). > With this move if the path has to be activated first, will the daemon have to call some sort of ps_path_is_initialized() function before it calls generic_make_request? It might be easier if mp's map_io call did not move so it or the ps could send commands and wait for the response before selecting a path. I guess this would mean you would have to add a access function for the tio's map_info so it could be set from the daemon, or mp may need to allocate its own io wrapper. It seems the latter may now be needed to give ps's a a map_info, becuase dm-mpath needs to store the path in the tio's map_info. Mike