This first week of the Linux 5.11 merge window continues to be very active with many of the kernel maintainers looking to land their changes ahead of the Christmas week where they are often taking time off work.

On top of other file-system improvements covered already for Linux 5.11 like a ton of Btrfs improvements and more F2FS encryption/casefolding/compression feature work , the Ceph, OverlayFS, and FUSE components all have some changes worth noting for Linux 5.11.

FUSE is worth noting because of improved performance for VirtIO-FS with mixed read/write workloads. This builds atop earlier VirtIO-FS performance work found in the prior kernel, Linux 5.10. The VirtIO-FS performance work this round is in regards to supporting FUSE_HANDLE_KILLPRIV_V2 and enabling SB_NOSEC. Those curious about the technical details to that performance work can see this patch series .

OverlayFS meanwhile is notable for now allowing unprivileged mounts. There is also support for running on copied file-system images by optionally disabling UUID verification.

Ceph meanwhile now supports the MSGR2 on-wire protocol that allows for full, in-transit encryption using AES-GCM. Plus there are fixes and other Ceph improvements.

Lots of great work continues to land for Linux 5.11 in what will make for a very exciting first stable kernel release of 2021. The Linux 5.11-rc1 release won't be out until 27 December while the stable debut should happen in February.