Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754866Ab1BOMqo (ORCPT ); Tue, 15 Feb 2011 07:46:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:25301 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754539Ab1BOMqn (ORCPT ); Tue, 15 Feb 2011 07:46:43 -0500 Date: Tue, 15 Feb 2011 12:46:29 +0000 From: Alasdair G Kergon To: Tejun Heo Cc: device-mapper development , Milan Broz , Jens Axboe , Tao Ma , linux-kernel@vger.kernel.org Subject: Re: [dm-devel] [PATCH][RFC] dm: Do not open log and cow device read-write for read-only mappings Message-ID: <20110215124629.GF5825@agk-dp.fab.redhat.com> Mail-Followup-To: Tejun Heo , device-mapper development , Milan Broz , Jens Axboe , Tao Ma , linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4D5A6EF4.3030905@redhat.com> Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1117 Lines: 29 On Tue, Feb 15, 2011 at 01:17:56PM +0100, Milan Broz wrote: > fd = open(device, O_RDWR | flags); > if (fd == -1 && errno == EROFS) { > *readonly = 1; > fd = open(device, O_RDONLY | flags); > } Would it be reasonable for your patch to return EROFS rather than EACCES? man 2 open: int open(const char *pathname, int flags, mode_t mode); EROFS pathname refers to a file on a read-only file system and write access was requested. EACCES The requested access to the file is not allowed, or search per‐ mission is denied for one of the directories in the path prefix of pathname, or the file did not exist yet and write access to the parent directory is not allowed. (See also path_resolu‐ tion(7).) Alasdair -- 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/