[$] Unique identifiers for NFS

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