Hi, I have been researching a customer issue related to oplocks in samba. To superficially summarize my understanding: oplocks resemble NFSv4 delegations in that a client can request revocable temporary authority over a file, which allows for locking operations and (write back/read ahead) caching locally on the client, eliminating network operations (and their latency) and thus improving performance.
I have read (but not actually reproduced) that on Linux the F_GETLEASE / F_SETLEASE fcntl() operations control NFSv4 delegations when issued on an NFSv4 based file handle. Also, I have seen a presentation stating that the OpenSolaris cifs server provides interoperability between SMB oplocks and NFSv4 delegations (but neither inspected the implementation at this point). My question is if there are any plans to integrate anything like F_GET/SETLEASE into OpenSolaris to allow user land processes (like samba) to control NFSv4 delegations and, for non NFS based files, get the same semantics locally? Or have I missed an existing interface? I guess this is not only an NFS specific question as it relates also to the VFS layer in general, but I am posting to this list as NFSv4 delegations would probably be the primary use case, IMHO. Nils This message posted from opensolaris.org
