On Thu, Aug 26 2010 at  6:50pm -0400,
Mike Snitzer [off-list ref] wrote:

Once we have a need for using request-based DM for something other than
multipath we can take a fresh look at implementing rq-based FLUSH+FUA.

Mike

p.s. I know how hard NEC worked on request-based DM's barrier support;
so I'm not suggesting this lightly.  For me it just seems like we're
carrying complexity in DM that hasn't ever been required.

To be clear: the piece that I was saying wasn't required is the need to
for request-based DM to clone a FLUSH to send to multiple targets
(saying as much was just a confusing distraction.. please ignore that).

Anyway, my previous email's question still stands.