What happened with btrfs during freeze of Debian Jessie?
Probably my previous message was misunderstood, so I try to rephrase it.
Current Debian Stable is Debian Jessie. The latest Linux kernel for Debian Jessie is 3.16. The said version of Linux kernel on the said version of Debian includes btrfs module. But documentation for this version of kernel says that "Btrfs is under heavy development, and is not suitable for
any uses other than benchmarking and review. The Btrfs disk format is not yet finalized." (Proof-link: https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/tree/Documentation/filesystems/btrfs.txt?id=refs/tags/v3.16.36) So it should be expected that btrfs module for this version of Linux kernel is very buggy and dangerous. But on the other hand, somehow it managed to survive freeze phase and make its way into Debian Stable.
How did it happen ?? O_o