EXT4 & Btrfs Get Additional Fixes With Linux 5.1
The EXT4 changes for this next Linux kernel release doesn't offer up any notable features but is predominantly comprised of bug fixes and clean-ups.
The only new "feature" for EXT4 in Linux 5.1 is the new /sys/fs/ext4/[disk]/journal_task attribute to expose the file-system's journal thread so that it can be moved into cgroup or for tracing purposes with the different frameworks like ftrace and perf. This at least is a useful addition for developers/administrators.
The list of EXT4 fixes is outlined via this pull request.
Dave Sterba sent in the main Btrfs changes last week that included configurable Zstd compression level support as its notable end-user feature. Sterba today sent in "Part 2" that includes a corruption fix when reading shared/compressed extents after hole punching, a deadlock between clone/dedupe and rename, and other minor fixes.