[dm-devel] [PATCH 2/4] md: add flush_idx support for stacked devices

[Mike Snitzer]

On Tue, Oct 14 2014 at  6:03am -0400,
Dmitry Monakhov <dmonakhov at openvz.org> wrote:

> For single device mapping it is safe to introduce get_flush_idx conception.
> This cover most common case linear mapping for a single dev.

You really should email the entire patchset rather than forcing the need
to hunt for the remainder of the patches that actually provide context
for this change.