The out-of-tree Reiser4 file-system driver has been updated with compatibility for the latest Linux 4.14 stable series. Besides reworking the code to run on Linux 4.14, this controversial file-system has also added support for Zstd file-system compression.
Linux 4.14 introduced Zstd support in the mainline kernel and wired it in for SquashFS and Btrfs. Our Btrfs Zstd benchmarks have been promising for transparent file-system compression compared to the other supported algorithms. Reiser4 has now picked up Zstd compression as an eventual replacement to their Gzip compression support.