From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alasdair G Kergon Subject: Re: semop failed for cookie? Date: Thu, 29 Apr 2010 01:00:45 +0100 Message-ID: <20100429000045.GF29708@agk-dp.fab.redhat.com> References: <4BD74F99.8020605@filteredperception.org> <20100427223323.GB29708@agk-dp.fab.redhat.com> <4BD8C0B2.7020509@filteredperception.org> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <4BD8C0B2.7020509@filteredperception.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Douglas McClendon Cc: dm-devel@redhat.com List-Id: dm-devel.ids On Wed, Apr 28, 2010 at 06:11:46PM -0500, Douglas McClendon wrote: > device-mapper: snaphots: Unable to perform snapshot handover until > source is suspended. It has never been OK to have the same snapshot metadata in use simultaneously in two targets at once (because of caching in memory). It's the responsibility of userspace to adhere to the correct semantics or live with the potential data corruption if they are violated. It sounds like your process may fall into that second category. Part of the process of adding snapshot merging support involved providing a controlled method for handing over the snapshot metadata from one target instance to another. If you are trying to move a snapshot from one target to another, then you must either deactivate the snapshot first (older kernels) or (newer kernels) make use of the 'snapshot handover' mechanism as the message suggests. Alasdair