[Qemu-devel] Backport of modern qemu rbd driver to qemu 1.0 + Precise packaging

[Alex Bligh]

I've backported the modern (qemu 1.5) rbd driver to qemu 1.0 (for anyone
interested). This is designed for people who are conservative in hypervisor
version, but like more bleeding edge storage.

The main thing this adds is asynchronous flush to rbd, plus automatic
control of rbd caching behaviour. I have NOT backported the extended
configuration bits.

I've used runtime testing through weak binding to detect the version
of librd in use, so it's possible to compile against a standard
Precise librbd, then run with a more modern one and take advantage
of async flush. It works the other way around too. Note the original
implementation of this posted to the qemu list (but not
taken) did not quite work.

The backport in qemu repository format can be found at
 https://github.com/flexiant/qemu/commits/v1.0-rbd-add-async-flush
(note the branch is v1.0-rbd-add-async-flush).

I've also backported this to the Ubuntu Precise packaging of qemu-kvm,
(again note the branch is v1.0-rbd-add-async-flush) at
 https://github.com/flexiant/qemu-kvm-1.0-noroms/tree/v1.0-rbd-add-async-flush

THESE PATCHES ARE VERY LIGHTLY TESTED. USE AT YOUR OWN RISK.

-- 
Alex Bligh