Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754490AbZKDDmu (ORCPT ); Tue, 3 Nov 2009 22:42:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754301AbZKDDmt (ORCPT ); Tue, 3 Nov 2009 22:42:49 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:34097 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754014AbZKDDms (ORCPT ); Tue, 3 Nov 2009 22:42:48 -0500 To: "Serge E. Hallyn" Cc: Greg Kroah-Hartman , Kay Sievers , Greg KH , linux-kernel@vger.kernel.org, Tejun Heo , Cornelia Huck , linux-fsdevel@vger.kernel.org, Eric Dumazet , Benjamin LaHaise , "Eric W. Biederman" Subject: Re: [PATCH 04/13] sysfs: Simplify sysfs_chmod_file semantics References: <1257249429-12384-4-git-send-email-ebiederm@xmission.com> <20091104024332.GA27639@us.ibm.com> From: ebiederm@xmission.com (Eric W. Biederman) Date: Tue, 03 Nov 2009 19:42:40 -0800 In-Reply-To: <20091104024332.GA27639@us.ibm.com> (Serge E. Hallyn's message of "Tue\, 3 Nov 2009 20\:43\:32 -0600") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in01.mta.xmission.com;;;ip=76.21.114.89;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 76.21.114.89 X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Scanned: No (on in01.mta.xmission.com); Exit with error (see exim mainlog) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2005 Lines: 45 "Serge E. Hallyn" writes: > Quoting Eric W. Biederman (ebiederm@xmission.com): >> From: Eric W. Biederman >> >> Currently every caller of sysfs_chmod_file happens at either >> file creation time to set a non-default mode or in response >> to a specific user requested space change in policy. Making >> timestamps of when the chmod happens and notification of >> a file changing mode uninteresting. > > But these changes can occur by togging values in sysfs files > (i.e. f71805f.c), right? Is this (specifically not doing inotify) > definately uncontroversial? The fs_notify_change was not introduced to deliberately support a feature but as a side effect of other cleanups. So there is no indication that anyone cares about inotify support. > I can't exactly picture an admin sitting there watching > nautilus for a sysfs file to become writeable, but could > imagine some site's automation getting hung... Or am I way > off base? I would be stunned if the shell script in the automation that writes to a sysfs file to make things writeable doesn't on it's next line kick off whatever needs it to be writable. With no benefit to using inotify and with only a handful of sysfs files affected I don't expect this change to break anything in userspace and I have been happily running with it for a year or so on all of our machines at work with no one problems. The reason I am making the change is that the goal of this patchset is to get sysfs to act like any other distributed filesystem in linux, and to use the same interfaces in roughly the same ways as other distributed filesystems. Unfortunately there is not a good interface for distributed filesystems to support inotify or I would use it. Eric -- 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/