From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752441AbaDUQOg (ORCPT ); Mon, 21 Apr 2014 12:14:36 -0400 Received: from 216-12-86-13.cv.mvl.ntelos.net ([216.12.86.13]:41808 "EHLO brightrain.aerifal.cx" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750772AbaDUQOe (ORCPT ); Mon, 21 Apr 2014 12:14:34 -0400 Date: Mon, 21 Apr 2014 12:10:04 -0400 From: Rich Felker To: "Michael Kerrisk (man-pages)" Cc: Jeff Layton , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, samba-technical@lists.samba.org, Ganesha NFS List , "Carlos O'Donell" , libc-alpha , "Stefan (metze) Metzmacher" Subject: Re: [PATCH] locks: rename file-private locks to file-description locks Message-ID: <20140421161004.GC26358@brightrain.aerifal.cx> References: <1398087935-14001-1-git-send-email-jlayton@redhat.com> <20140421140246.GB26358@brightrain.aerifal.cx> <535529FA.8070709@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <535529FA.8070709@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 21, 2014 at 04:23:54PM +0200, Michael Kerrisk (man-pages) wrote: > On 04/21/2014 04:02 PM, Rich Felker wrote: > > On Mon, Apr 21, 2014 at 09:45:35AM -0400, Jeff Layton wrote: > >> File-private locks have been merged into Linux for v3.15, and *now* > >> people are commenting that the name and macro definitions for the new > >> file-private locks suck. > >> > >> ....and I can't even disagree. The names and command macros do suck. > >> > >> We're going to have to live with these for a long time, so it's > >> important that we be happy with the names before we're stuck with them. > >> > >> The consensus on the lists so far is that they should be rechristened as > >> "file-description locks". > >> > >> This patch makes the following changes that I think are necessary before > >> v3.15 ships: > >> > >> 1) rename the command macros to their new names. These end up in the uapi > >> headers and so are part of the external-facing API. It turns out that > >> glibc doesn't actually use the fcntl.h uapi header, but it's hard to > >> be sure that something else won't. Changing it now is safest. > >> > >> 2) make the the /proc/locks output display these as type "FDLOCK" > >> > >> The rest of the renaming can wait until v3.16, since everything else > >> isn't visible outside of the kernel. > > > > I'm sorry I didn't chime in on this earlier, but I really prefer the > > (somewhat bad) current naming ("private") to the > > ridiculously-confusing use of "FD" to mean "file descriptION" when > > everybody is used to it meaning "file descriptOR". The potential for > > confusion that these are "file descriptOR locks" (they're not) is much > > more of a problem, IMO, than the confusion about what "private" means > > (since it doesn't have an established meaning in this context. > > > > Thus my vote is for leaving things the way the kernel did it already. > > There's at least two problems to solve here: > > 1) "File private locks" is _meaningless_ as a term. Elsewhere That's the benefit of it: it doesn't clash with any already-established meaning. I agree it's less than ideal, but all the alternatives I've seen so far are worse. > (http://thread.gmane.org/gmane.network.samba.internals/76414/focus=1685376), > I suggested various alternatives. "File-handle locks [*]" was my This is also bad. "Handle" also has a defined meaning in POSIX. See XSH 2.5.1: http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html > initial preference, and I also suggested "file-description locks" > and noted the drawbacks of that term. I think it's insufficient > to say "stick with the existing poor name"--if you have > something better, then please propose it. (Note by the way > that for nearly a decade now, the open(2) man page has followed > POSIX in using the term "open file description. Full disclosure: > of course, I'm responsible for that change in the man page.) I'm well aware of that. The problem is that the proposed API is using the two-letter abbreviation FD, which ALWAYS means file descriptor and NEVER means file description (in existing usage) to mean file description. That's what's wrong. > 2) The new API constants (F_SETLKP, F_SETLKPW, F_GETLKP) have names > that are visually very close to the traditional POSIX lock names > (F_SETLK, F_SETLKW, F_GETLK). That's an accident waiting to happen > when someone mistypes in code and/or misses such a misttyping > when reading code. That really must be fixed. I agree, but I don't think making it worse is a solution. Rich