From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [PATCH v2] dm snapshot: revise snapshot_resume's exception handover Date: Wed, 4 Nov 2009 17:20:52 -0500 Message-ID: <20091104222052.GA21348@redhat.com> References: <1257371140-18483-1-git-send-email-snitzer@redhat.com> <20091104221148.GA19580@redhat.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20091104221148.GA19580@redhat.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: Alasdair G Kergon Cc: dm-devel@redhat.com List-Id: dm-devel.ids On Wed, Nov 04 2009 at 5:11pm -0500, Mike Snitzer wrote: > Until now snapshot_resume only allowed the resuming snapshot to get the > exception store from another snapshot. > > Revise snapshot_resume's exception handover to allow a snapshot to > handover its exceptions to another snapshot prior to resuming. > > This is needed to accomodate the following sequence: > new_snapshot->ctr > old_snapshot->suspend > old_snapshot->resume > new_snapshot->resume > > lvm2 relies on this sequence if 'lvchange --refresh' is used to start a > snapshot merge that was deferred until both origin and snapshot were not > in use. FYI, the above is the last of 3 patches in the "exception handover" series, the patch order is: dm snapshot: initial support for exception handover http://patchwork.kernel.org/patch/55022/ dm snapshot: exception handover improvements http://patchwork.kernel.org/patch/55569/ dm snapshot: revise snapshot_resume's exception handover http://patchwork.kernel.org/patch/57787/