Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764309AbXJEUuP (ORCPT ); Fri, 5 Oct 2007 16:50:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762541AbXJEUuA (ORCPT ); Fri, 5 Oct 2007 16:50:00 -0400 Received: from extu-mxob-2.symantec.com ([216.10.194.135]:18588 "EHLO extu-mxob-2.symantec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761487AbXJEUt7 (ORCPT ); Fri, 5 Oct 2007 16:49:59 -0400 Date: Fri, 5 Oct 2007 21:49:45 +0100 (BST) From: Hugh Dickins X-X-Sender: hugh@blonde.wat.veritas.com To: Guennadi Liakhovetski cc: linux-kernel@vger.kernel.org Subject: Re: tmpfs disabled in .config but in /proc/filesystems In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1819 Lines: 44 On Fri, 5 Oct 2007, Guennadi Liakhovetski wrote: > On Fri, 5 Oct 2007, Hugh Dickins wrote: > > On Fri, 5 Oct 2007, Guennadi Liakhovetski wrote: > > > Am I running crazy here (some 2.6.23-rc6-ish)? > > > > > > $ zcat /proc/config.gz | grep TMPFS > > > # CONFIG_TMPFS is not set > > > $ grep tmpfs /proc/filesystems > > > nodev tmpfs > > > > tmpfs (mm/shmem.c) is used by the kernel to support shared memory > > of various kinds even when CONFIG_TMPFS is not set. But only when > > CONFIG_TMPFS=y can users mount a tmpfs as a fully capable filesystem. > > Confusing, yes: sorry for putting the fear of craziness upon you. > > Oops, sorry, now I remember reading about this... As a matter of fact, the > presence in /proc/filesystem - was it a deliberate decision, or > technically preferrable or a mistake? d) None of the above! I've never really thought about it, but I think it's simply a natural side-effect of the register_filesystem and vfs_kern_mount it has to do in order to get the services it needs from the VFS. If I were to look back in history, I expect I'd find that it used to display as "shmfs" or "shmemfs" rather than "tmpfs", and that we adjusted the naming later on. You might prefer that we hadn't, or that we registered under both names if CONFIG_TMPFS (maybe we did do it like that at one stage, I vaguely remember but haven't checked). > Wouldn't it be more logical to > completely hide it from the user then? Sorry, I find it hard to get excited about! I'm inclined not to mess around with it now. With apologies to your sanity ;) Hugh - 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/