From: Stas Sergeev Subject: Unable to use ext4 as root fs Date: Sun, 01 Nov 2009 23:07:04 +0300 Message-ID: <4AEDEA68.3080803@aknet.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit To: ext4 Return-path: Received: from imp03.mtu.ru ([62.5.255.20]:34739 "EHLO imp03.mtu.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753356AbZKAUMt (ORCPT ); Sun, 1 Nov 2009 15:12:49 -0500 Received: from imp01.mtu.ru (alt-proxy-1.mtu.ru [62.5.255.74]) by ss27-so02.mtu.ru (Postfix) with ESMTP id A8082229680 for ; Sun, 1 Nov 2009 23:06:55 +0300 (MSK) Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi. I am trying to move my PC from ext3 to ext4, and so far I can't get it to boot. I am getting this: --- EXT3-fs: sda3: couldn't mount because of unsupported optional features (240). --- Google reveals that this is normal, and the next thing would be the ext4 mount, but this doesn't happen. The current git kernel just locks up tight after that message. NMI watchdog doesn't do anything. The Fedora kernel doesn't lock up, the keyboard works, you can Ctrl-Alt-Del, but nothing happens, ext4 does not mount. I know that ext4 support is compilled in (builtin, not a module), because this very kernel mounts ext4 fine if I boot from ext3 root fs. Now, with the lack of the usual "unable to mount root, kernel panic", I am starting to suspect a bug somewhere. Can someone please give me the hint about what have to be done to boot from ext4? Or, in case there is nothing special to do, where should I start sticking printk's to get that somehow debugged?