From: Ted Ts'o Subject: Re: CONFIG_EXT4_USE_FOR_EXT23: rootfs shows as ext2 instead of ext4 Date: Tue, 12 Apr 2011 20:49:38 -0400 Message-ID: <20110413004938.GE3682@thunk.org> References: <4DA48AF4.5080803@teksavvy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linux Kernel , linux-ext4@vger.kernel.org To: Mark Lord Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:42599 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756910Ab1DMAtm (ORCPT ); Tue, 12 Apr 2011 20:49:42 -0400 Content-Disposition: inline In-Reply-To: <4DA48AF4.5080803@teksavvy.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Apr 12, 2011 at 01:25:08PM -0400, Mark Lord wrote: > Ted et al. > > I've only just noticed this, so I have no idea how long it has been this way. > > When I build a kernel with CONFIG_EXT4_USE_FOR_EXT23=y and boot from it, > the ext4 root filesystem shows up as "ext2" mode, rather than "ext4". > > This looks very wrong to me, and quite dangerous. It's a cosemtic bug, I agree, but I'm not sure why you consider it dangerous. CONFIG_EXT4_USE_FOR_EXT23 means that ext4 registers itself as ext2 and/or ext3, if ext2 and/or ext3 are not configured into the kernel. Since the kernel tries to mount the file system as ext2, ext3, and then ext4, and uses whichever one works first. - Ted