This news from Chris Mason on the linux-btrfs mailing list:
Just a quick note that Linus merged the btrfs unstable repository into the mainline kernel. I’ll cut a new stable release of btrfs-progs on Monday to go with it (for now the unstable repo is the best choice).
I’d like to thank everyone who contributed to the code, tested, reviewed, documented, helped organize and otherwise helped Btrfs get as far as it has. It wouldn’t have been possible without you.
There is a lot of work to do before we can really declare Btrfs finished, but this is a huge step forward.
Yay! Congratulations Chris.. 🙂
For those who want to know more about btrfs, please check out its wiki page..