[lvm-devel] Re: [PATCH 02/15] lvm-merge-metadata

[Mike Snitzer]

On Fri, Nov 20 2009 at  6:26pm -0500,
Zdenek Kabelac <zkabelac at redhat.com> wrote:

> Dne 20.11.2009 23:35, Mike Snitzer napsal(a):
> > From: Mikulas Patocka <mpatocka at redhat.com>
> > 
> > Add 'SNAPSHOT_MERGE' lv_segment 'status' flag.
> > 
> > Make 'merging_snapshot' pointer that points from the origin to the
> > segment that represents the merging snapshot.
> > 
> > Import/export 'merging_store' metadata.
> > 
> > Do not allow creating snapshots while another snapshot is merging.
> > Snapshot created in this state would certainly contain invalid data.
> > 
> > diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
> > index e9a3d5d..30073d3 100644
> > --- a/lib/metadata/metadata-exported.h
> > +++ b/lib/metadata/metadata-exported.h
> > @@ -60,6 +60,7 @@
> >  //#define ACTIVATE_EXCL		0x00100000U	/* LV - internal use only */
> >  //#define PRECOMMITTED		0x00200000U	/* VG - internal use only */
> >  #define CONVERTING		0x00400000U	/* LV */
> > +#define SNAPSHOT_MERGE		0x00800000U	/* SEG */
> >  
> >  #define MISSING_PV              0x00800000U	/* PV */
> 
> I think reusing these bitfields might lead to unexpected troubles.

Nice catch, surprised I missed that.

Looks like I'll go with:
#define SNAPSHOT_MERGE          0x10000000U