From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758517AbZCJQyK (ORCPT ); Tue, 10 Mar 2009 12:54:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757402AbZCJQqr (ORCPT ); Tue, 10 Mar 2009 12:46:47 -0400 Received: from smtpfb2-g21.free.fr ([212.27.42.10]:42890 "EHLO smtpfb2-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757371AbZCJQqq (ORCPT ); Tue, 10 Mar 2009 12:46:46 -0400 Date: Tue, 10 Mar 2009 17:26:44 +0100 (CET) From: porte64@free.fr To: linux-kernel@vger.kernel.org Message-ID: <355270241.1702481236702404399.JavaMail.root@spooler8-g27.priv.proxad.net> Subject: read-only partitions: does the policy apply to all metadata ? MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [127.0.0.1] X-Mailer: Zimbra 5.0.15_GA_2815.UBUNTU8_64 (zclient/5.0.15_GA_2815.UBUNTU8_64) X-Authenticated-User: porte64@free.fr Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, When a partition is mounted as read-only, does the kernel really prevent ANY byte to be written to it, including any metadata ? (i am thinking here about file attributes -- last access time, as well as meta information about filesystem/blocks description etc ...). And is the policy implemented in every filesystem type driver or at some abstraction level (as if the write() and like system calls were designed to return an error). Unfortunately, on common (all?) hard drives, there seems to be no switch to set the device microcode in read-only mode. By the way, this makes me also thing about memory cards with locks: is it a real protection or it is just a setting which tells the kernel that it *SHOULD* mount the device read-only ? Please include my private address if you answer; i posted to the list because in some other forums we did not come up with a clear answer, so this is my last chance to get a definite done. However i didn't subscribe to the list as i have realized i am not able to help unfortunately: operating systems are the most complex thing ever design by humans ! Best regards Phil