Btrfs Set To Land Support For IDMAPPED Mounts In Linux 5.15

Introduced to the Linux kernel earlier this year with Linux 5.12 was IDMAPPED mounts that allow for different mounts to expose the same file or directory with different ownership. IDMAPPED mounts was designed with use-cases ranging from containers to systemd-homed and more as outlined in the earlier article. Btrfs is now ready to begin supporting IDMAPPED mounts.

Back when IDMAPPED mounts functionality was added to the Linux kernel, the initial implementation came for FAT and EXT4. XFS support has also been in the works while now for Linux 5.15 the Btrfs support appears ready.

Following a number of patches being queued into the Btrfs kernel development tree, IDMAPPED mounts are now allowed. With various Btrfs changes by Canonical's Christian Brauner, the IDMAPPED mounts support is ready.

With the code now being queued into the Btrfs "for-next" Git code, it makes it material for the upcoming Linux 5.15 merge window.

More details on IDMAPPED mounts functionality can be found via Christian Brauner's FOSDEM 2021 presentation.