From: Theodore Tso Subject: Re: [QUESTION] root ext4 strange couldn't mount/can mount report Date: Tue, 27 Jan 2009 10:37:06 -0500 Message-ID: <20090127153706.GD11843@mit.edu> References: <20090127134231.6daf4cbb@sauron.linicks.net> <20090127141426.GC11843@mit.edu> <20090127143714.2389b5c2@sauron.linicks.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Nick Warne Return-path: Received: from thunk.org ([69.25.196.29]:44233 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752794AbZA0PhL (ORCPT ); Tue, 27 Jan 2009 10:37:11 -0500 Content-Disposition: inline In-Reply-To: <20090127143714.2389b5c2@sauron.linicks.net> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Jan 27, 2009 at 02:37:14PM +0000, Nick Warne wrote: > > I see. I currently build ext3 in the kernel (as well as ext4), as > I keep /boot partition ext3 for bootloader lilo. > > So I can remove ext3 now, and lilo and kernel ext4 will happily read > and use /boot partition as ext3 OK? The only thing which might not work is automatic type detection with mount. That is, if you specify: mount /dev/hda1 /boot without specifying a filesystem type, /bin/mount will probably do an automatic type detection, detect that the filesystem is an ext3 filesystem, and attempt to mount it as ext3, and not know to try it with ext4. Libraries such as blkid and fsid could be made smart enough to do the right thing, but they don't at the moment. But if you type "mout -t ext4 /dev/sda1 /boot", you can mount an ext3 filesystem using the ext4 filesystem driver, and with 2.6.29 and up, you'll be able to mount ext2 filesystems using the ext4 filesystem code. (You'll also be able to create extent-based filesystems without a journal, which is why Google contributed the support for this.) - Ted