From: Ted Ts'o Subject: Re: Bug In ext4 in kernels > 2.6.39 - Not mounting with arguments/options I specify in fstab on root remount Date: Sat, 22 Oct 2011 05:32:18 -0400 Message-ID: <20111022093218.GF4196@thunk.org> References: <4E6F1B49.3010803@gmail.com> <4E6F6D89.5040905@redhat.com> <20111009234433.GU7948@thunk.org> <4EA0E72D.8020305@gmail.com> <20111022050031.GC4196@thunk.org> <4EA27607.20407@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Sandeen , linux-ext4@vger.kernel.org To: Matt Parnell Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:56398 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792Ab1JVJcX (ORCPT ); Sat, 22 Oct 2011 05:32:23 -0400 Content-Disposition: inline In-Reply-To: <4EA27607.20407@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sat, Oct 22, 2011 at 02:51:35AM -0500, Matt Parnell wrote: > That doesn't really help me at all, it's not > rootflags=data=writeback causing this, it's starting to make me > think that arch's init may be to blame, although I previously ruled > it out... Well, it looks like rootflags=data=writeback is not making it to the file system. That's why it's not showing up in /proc/mounts, from you showed us. Can you look at the kernel dmesg? You should see something like this: [ 1.421146] EXT3-fs (vda): error: couldn't mount because of unsupported optional features (240) [ 1.434057] EXT4-fs (vda): couldn't mount as ext2 due to feature incompatibilities [ 1.454631] EXT4-fs (vda): mounted filesystem with writeback data mode. Opts: data=writeback [ 1.455966] VFS: Mounted root (ext4 filesystem) readonly on device 254:0. The first line is the failure to mount the root file system as ext3. The 2nd is the failure to mount the file system as ext2, using the ext4 file system driver. The last two lines show the options show the mount as ext4. What do those two lines look to you. If you don't see "Opts: data=writeback", then somehow the rootflags option isn't getting passed down to the file system. Then when you try to remount the file system read/write, the fact that you have "data=writeback" in your /etc/fstab causes the failure to remount. If you simply remove that from /etc/fstab, things should work better. The remount will preserve whatever data=journalling mode was in use when the root file system was originallymounted as. If rootflags is non-functional, then the file system won't be mounted as data=writeback, but at least the boot sequence will continue without blowing out. - Ted