Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758510Ab1FQWGQ (ORCPT ); Fri, 17 Jun 2011 18:06:16 -0400 Received: from astoria.ccjclearline.com ([64.235.106.9]:37215 "EHLO astoria.ccjclearline.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751901Ab1FQWGO (ORCPT ); Fri, 17 Jun 2011 18:06:14 -0400 Date: Fri, 17 Jun 2011 18:06:06 -0400 (EDT) From: "Robert P. J. Day" X-X-Sender: rpjday@localhost6.localdomain6 To: Linux Kernel Mailing List Subject: should CONFIG_TMPFS_POSIX_ACL be so easily deselectable? Message-ID: User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - astoria.ccjclearline.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - crashcourse.ca X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2570 Lines: 65 long story short: in updating to a slightly newer hand-rolled kernel (2.6.39-rc7 -> 3.0.0-rc3) on my ubuntu system, i somehow (no idea how) managed to deselect CONFIG_TMPFS_POSIX_ACL without realizing it. the consequences of this were that sound suddenly disappeared under the new kernel, for a fairly obvious reason -- ALSA needs ACLs under /dev to give R/W access to the user to the device files under /dev/snd/. as i said, i have no idea how i managed to do this but i eventually tracked it down, re-selected that option, rebuilt and i have sound again. but i noticed that in fs/Kconfig, that option is independently selectable from TMPFS, so it's (as i learned) deviously easy to deselect, with annoying consequences. more to the point, given the apparent necessity of ACLs under /dev for proper sound operation, the help info for that option seems a bit misleading: config TMPFS_POSIX_ACL bool "Tmpfs POSIX Access Control Lists" depends on TMPFS select TMPFS_XATTR select GENERIC_ACL help ... snip ... If you don't know what Access Control Lists are, say N. yeah, i think that help line might not want to dismiss tmpfs ACLs quite so quickly. thoughts? rday p.s. i do notice a fairly recent change to that config file related to this: commit 4db70f73e56961b9bcdfd0c36c62847a18b7dbb5 Author: Eric Paris Date: Wed May 25 19:49:18 2011 -0700 tmpfs: fix XATTR N overriding POSIX_ACL Y Choosing TMPFS_XATTR default N was switching off TMPFS_POSIX_ACL, even if it had been Y in oldconfig; and Linus reports that PulseAudio goes subtly wrong unless it can use ACLs on /dev/shm. Make TMPFS_POSIX_ACL select TMPFS_XATTR (and depend upon TMPFS), and move the TMPFS_POSIX_ACL entry before the TMPFS_XATTR entry, to avoid asking unnecessary questions then ignoring their answers. -- ======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca Twitter: http://twitter.com/rpjday LinkedIn: http://ca.linkedin.com/in/rpjday ======================================================================== -- 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/