[$] The FUSE BPF filesystem

The Filesystemin Userspace (FUSE) framework can be used to create a "stacked"filesystem, where the FUSE piece adds specialized functionality(e.g. reporting different file metadata) atop anunderlying kernel filesystem. The performance of such filesystems leaves alot to be desired, however, sothe FUSEBPF filesystem has been proposed to try to improve the performance tobe close to that of the underlying native filesystem. It came up in thecontext of a session on FUSE passthroughearlier in the2023 Linux Storage, Filesystem,Memory-Management and BPF Summit, but the details of FUSE BPF were morefully described by Daniel Rosenberg in a combined filesystem and BPFsession on the final day of the summit.