Status of dedupe in btrfs

Hello everyone,

I was reading this article in Slashdot about dedupe [1] and i was wondering about the status of the (offline) dedupe patches in btrfs. Are they applicable to a recent kernel? do userspace tools support it?

Kind regards

[1] http://sk.slashdot.org/story/12/01/04/1955248/ask-slashdot-freeopen-deduplication-software