Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933322AbaD2IjB (ORCPT ); Tue, 29 Apr 2014 04:39:01 -0400 Received: from mail-ee0-f54.google.com ([74.125.83.54]:55209 "EHLO mail-ee0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755863AbaD2Ii6 (ORCPT ); Tue, 29 Apr 2014 04:38:58 -0400 Message-ID: <535F651E.6090204@gmail.com> Date: Tue, 29 Apr 2014 10:38:54 +0200 From: "Michael Kerrisk (man-pages)" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Jeff Layton CC: mtk.manpages@gmail.com, Ganesha NFS List , lkml , Linux-Fsdevel , Trond Myklebust , "J. Bruce Fields" , Neil Brown , samba-technical@lists.samba.org, "Michael Kerrisk (gmail)" Subject: OFD ("file private") locks and NFS Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jeff, I've been looking a bit at the fcntl() documentation of traditional (F_SETLK) record locking, and a question just jumped out at me. Is it worth considering some future-proofing in the design of OFD locks ("open file description locks", formerly known as "file-private locks")? What I am thinking of here is that on some systems, the traditional 'struct flock' has a nonstandard field, l_sysid, that is used on F_GETLK to identify the remote system on which a lock is held. Should the design of OFD locks allow for such a field (now, or in the future), which might be useful in the context of locking on network file systems such as NFS. Put more simply, should the new OFD locking system be using a new structure for describing locks, rather than the traditional 'struct flock'? Defining a new structure, might be useful to allow for future extensions to the API. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/