Btrfs In Linux 3.3 Brings Reworked Balance Code

On the same day as talking about Microsoft's new Resilient File System, the pull request for Btrfs in the Linux 3.3 kernel was sent in and subsequently pulled. This file-system update does bring a few notable changes.

Btrfs with Google Snappy compression support didn't make it for Linux 3.3 (it was a last-minute request and there's at least LZO and Gzip file-system compression already available), but there are some notable changes. However, the 3.3 changes also aren't as noticeable as the beefy Btrfs changes found in Linux 3.2.

- The balance code for handling RAID with Btrfs has been re-worked, which is the biggest change in this pull request. "The biggest change in here is Ilya Dryomov's reworking of the btrfs balance code. It can now pause, resume, give status updates, and restripe between different raid levels. It also lets you filter the balance based on metadata/data profiles, and lets you only balance mostly empty block groups."

- The back reference walker code for Btrfs has been largely re-written. This code is used by scrub and in the future for per-subvolume quotas.

- Bulk trimming and allocator fixes can also be found in this pull.

Further details on the Btrfs pull request for Linux 3.3, which was already pulled into the tree of Linus Torvalds this evening, can be found in the kernel mailing list message.