From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754558AbaFWJXS (ORCPT ); Mon, 23 Jun 2014 05:23:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26841 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752387AbaFWJXR (ORCPT ); Mon, 23 Jun 2014 05:23:17 -0400 Date: Mon, 23 Jun 2014 11:22:56 +0200 From: Karel Zak To: Philippe De Muyter Cc: Dave Chinner , Andrew Morton , linux-kernel@vger.kernel.org, Al Viro Subject: Re: [PATCH] init/do_mounts.c: treat EROFS like EACCES Message-ID: <20140623092256.GE25885@x2.net.home> References: <1403107964-1082-1-git-send-email-phdm@macqel.be> <20140619141950.18b9026d7d06694291eea311@linux-foundation.org> <20140619230924.GO4453@dastard> <20140620131328.GA31693@frolo.macqel> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140620131328.GA31693@frolo.macqel> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 20, 2014 at 03:13:28PM +0200, Philippe De Muyter wrote: > On Fri, Jun 20, 2014 at 09:09:24AM +1000, Dave Chinner wrote: > > On Thu, Jun 19, 2014 at 02:19:50PM -0700, Andrew Morton wrote: > > > On Wed, 18 Jun 2014 18:12:44 +0200 Philippe De Muyter wrote: > > > > > > > some combinations of filesystem and block device (at least vfat on mmc) > > > > yield -EROFS instead of -EACCES when the device is read-only. Retry > > > > mounting with MS_RDONLY set, just like for the EACCES case, instead of > > > > failing directly. > > > > > > > > ... > > > > > > > > --- a/init/do_mounts.c > > > > +++ b/init/do_mounts.c > > > > @@ -394,6 +394,7 @@ retry: > > > > case 0: > > > > goto out; > > > > case -EACCES: > > > > + case -EROFS: > > > > flags |= MS_RDONLY; > > > > goto retry; > > > > case -EINVAL: > > > > > > hm, what's going on here. I'd have thought it to be very logical that > > > file_system_type.mount() would return EROFS if the device is read-only! > > > But I'm suspecting that there is some convention that the fs is > > > supposed to return EACCES in this case. So *perhaps* it is vfat-on-mmc > > > which needs fixing. Dunno. > > > > > > Al, are you able to shed light? > > > > from the mount(2) man page: > > > > EACCES A component of a path was not searchable. (See also > > path_resolution(7).) Or, mounting a read-only filesystem > > was attempted without giving the MS_RDONLY flag. Or, the > > block device source is located on a filesystem mounted with > > the MS_NODEV option. > > > > So, when the device is read-only, the error should EACCES, not > > EROFS. Would seem to me that vfat-on-mmc needs fixing... Only code matters, we don't compile and execute man pages... ;-) > Looking at the sources of mount(1) > > https://github.com/karelzak/util-linux/blob/master/sys-utils/mount.c > > at line 601, we clearly see that mount(1) allows mount(2) to fail > with EROFS. BTW, comment from the original mount(8) code: case EACCES: /* pre-linux 1.1.38, 1.1.41 and later */ case EROFS: /* linux 1.1.38 and later */ Karel -- Karel Zak http://karelzak.blogspot.com