[$] Unique identifiers for NFS

In a combined filesystem and storage session at the 2022 Linux Storage,Filesystem, Memory-management and BPF Summit (LSFMM), Chuck Leverwanted to discuss the need for a permanent, globally unique ID for network filesystems. He was joined by Hannes Reinecke who has worked on theproblem for NVMe storage devices; Lever said something along thoselines is needed for NFSv4. He was hoping to find a solution during thesession, though it would seem that the solution may lie in user space-anddocumentation.