Comment 36 for bug 736743

Same problem.

Ubuntu 12.04 LTS Beta 1 - 64 bits
Fresh install on btrfs formatted from Ubiquity

$ mount
/dev/sda1 on / type btrfs (rw,subvol=@)
...
/dev/sda1 on /home type btrfs (rw,subvol=@home)