Dave Chinner, the XFS file-system maintainer, characterizes the XFS pull request as having "lots of changes all over the place" for the 3.16 merge window. XFS for the Linux 3.16 kernel has picked up a new on-disk btree for tracking free inodes, an optimized and reworked inode allocator to make use of the new data, and there's various clean-ups and reworks of existing XFS features. The XFS changes can be found via this pull request.
Chris Mason at Facebook meanwhile filed all of the Btrfs file-system changes for Linux 3.16. Btrfs in this next kernel version has a rework of the Btrfs quota accounting to improve in-memory tracking of delayed extent operations, Btrfs stack usage improvements, corruption fixes, and other clean-ups and optimizations throughout the promising next-gen Linux file-system. Btrfs changes for Linux 3.16 can be viewed via this pull request.
Later this month once we're past the 3.16 merge window we'll go ahead with our usual Linux HDD/SSD file-system benchmarks of the new kernel.