[dm-devel] Re: [PATCH v2] dm snapshot: revise snapshot_resume's exception handover

[Mike Snitzer]

On Wed, Nov 04 2009 at  5:11pm -0500,
Mike Snitzer <snitzer at redhat.com> 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/