FUSE In Linux 6.12 Adds Idmapped Mounts & Writeback Optimization

File-systems in user-space continue to become more robust with the latest FUSE updates merged for Linux 6.12.

The leading new FUSE feature for Linux 6.12 is supporting Idmapped mounts for that functionality of use from containers to systemd-homed and more. The Idmapped mounts code allows for different moutns to expose the same files/directory with different ownership such as for sharing files between multiple users/systems. Linux has been steadily supporting Idmapped mounts on more file-systems and now with Linux 6.12 it’s available to FUSE user-space file-systems.

The Idmapped mounts FUSE code for Linux 6.12 is initially in place for VirtIO-FS to help with virtualized guest VMs.

Also notable with FUSE for Linux 6.12 is an optimization when checking for writeback. This can help in scenarios like having multiple readers of the same file without any writers or where the page cache is disabled.

Tracepoint support is also added to FUSE along with code clean-ups. See this pull request for the full list of FUSE feature updates merged for Linux 6.12.