Hello Chuck, have you done more research on this as mentioned? I think that this is really useful for non-POSIX clients as NFS4 ACLs are not-POSIX; knfsd is already translating POSIX ACLs to non-POSIX NFS4 ACLs, and this is just an improvement to covert also the POSIX-sticky-bit in non-POSIX NFS4 ACL. Also another improvement is that this change allows to modify all parts of POSIX access mode (sticky bit, base mode permissions r/w/x and POSIX ACL) via NFS4 ACL structure. So non-POSIX NFS4 client would be able to add or remove directory sticky bit via NFS4 ACL editor. Of course, nothing from this is required by RFC8881 specification, but specification also does not disallow this for NFS4 servers. It is improvement for non-POSIX clients. POSIX clients would of course not use it.
