On Wed, Apr 25, 2012 at 08:50:02PM +1000, NeilBrown wrote:

> So maybe something like that (completely untested as yet) ??
> (and this seems to have changed between 3.3 and 3.4 which confused me
> a bit.  But if you think this approach is OK I'll come up with something
> that is right for 3.4).

Yes, that looks reasonable.