SUSE engineer David Sterba submitted the Btrfs pull request for Linux 6.19 on Friday, ahead of the Linux 6.18 stable kernel release that took place on Sunday. This copy-on-write file-system continues seeing some enticing feature work and other improvements for this next version of the Linux kernel.
With the Linux 6.18 kernel Btrfs added experimental support for block sizes greater than the page size. That “BS > PS” work continues being built out in Linux 6.19. The code now supports more operations when not using large folios, like encoded read/write and Btrfs SEND support. Btrfs’ native RAID5 / RAID6 support is also now able to handle the block size being greater than the page size.
A new experimental feature with Linux 6.19 for Btrfs is shutdown ioctl support for being able to set the file-system state as being shutdown and for pending operations attempting to finish them in time. With the “CONFIG_BTRFS_EXPERIMENTAL” mode, checksum calculations are now offloaded to the process context in order to simplify locking and a speed improvement in direct I/O throughput with buffered I/O being around +15% when not offloaded. In the future this offloaded checksum calculation mode will likely be enabled by default.
Btrfs’ scrub and device replace functionality will also better cope with suspend/hibernate events. A running Btrfs scrub job when the system attempts to suspend will now suspend the scrub and replace any device replace event as well. The device replace process has to be restarted from the beginning on system resume.
Btrfs is also bringing improvements to processing of space reservation tickets by optimizing locking and shrinking critical sections. Lockstat numbers are up by around 15% with this change.
Last but certainly not least, Btrfs continues making more preparations for ultimately supporting FSCRYPT like other prominent Linux file-systems. FSCRYPT will allow native file-system encryption support within Btrfs in a future version of the Linux kernel.
More details on these changes and other Btrfs improvements for Linux 6.19 via this pull request.
