David Sterba of SUSE sent in the Btrfs file-system updates today for the Linux 4.19 kernel merge window.

The most noticeable change with Btrfs for Linux 4.19 is that it now supports defragging opened read-only files that have read-write permissions. Btrfs in Linux 4.19 is also carrying some validation improvements, error code handling improvements, tree checker improvements, some fsync fixes, a possible deadlock fix, resetting the on-disk device stats value after replacing a drive, and a variety of other code clean-ups and bug fixes.

More details on the Btrfs file-system work for Linux 4.19 can be found via this pull request with the complete list of patches. While fixing a number of bugs and making improvements in the process, this PR actually lightens the Btrfs kernel code by over one thousand lines of code.