From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: [RFC] New interface for dm-io to handle timed requests Date: Tue, 14 Mar 2006 14:15:10 -0600 Message-ID: <4417244E.5080707@cs.wisc.edu> References: <44169897.1080900@de.ibm.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <44169897.1080900@de.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids Stefan Bader wrote: > Some days ago we proposed an extension to the device mapper that allows > to specify a timeout after which a given request should return as > successful, even if some of the target devices did not react by that > time. As we cannot return a request to the upper layers as long as some > io is still running and possibly modifying referenced pages, we also > need a way to handle those requests. > The ideal solution would be to have an interface in the block layer that > allows us to cancel any submitted requests. But since such a change will > take quite a lot discussions and work, we want to emulate such a > behavior in the dm core for now. > The scsi people and some block people have been talking about moving more error handling functionality into the block layer for a while and it is slowing moving that way. It could probably be done faster if people did not concentrate on one subsystem :) Maybe you should post to lkml and linux-scsi and get some responses from them before adding it to dm core. If a post already went out to those list my fault for missing it.