Last week was the main Btrfs pull request with the big Btrfs ENOSPC rework that can enhance throughput and lower latencies. In fact, the earlier pull request mentioned the new ENOSPC code is "dramatically faster."
Chris Mason of Facebook has now sent in a second pull request for the 4.8 merge window. This second update has mostly cleanups and fixes, but still it's a hearty bunch: around one thousand lines of code changes.
Details on all those changes via this secondary pull request. I can't wait to start benchmarking Btrfs (and the other file-systems) of Linux 4.8 next week.