From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758051AbYIALkc (ORCPT ); Mon, 1 Sep 2008 07:40:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751276AbYIALkX (ORCPT ); Mon, 1 Sep 2008 07:40:23 -0400 Received: from hera.kernel.org ([140.211.167.34]:54577 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751056AbYIALkW (ORCPT ); Mon, 1 Sep 2008 07:40:22 -0400 Message-ID: <48BBD429.50907@kernel.org> Date: Mon, 01 Sep 2008 13:38:17 +0200 From: Tejun Heo User-Agent: Thunderbird 2.0.0.12 (X11/20071114) MIME-Version: 1.0 To: Jens Axboe CC: Bartlomiej Zolnierkiewicz , Stephen Rothwell , linux-next@vger.kernel.org, LKML , Ingo Molnar , dm-devel@redhat.com Subject: Re: [PATCH #blk-for-2.8] init: DEBUG_BLOCK_EXT_DEVT requires explicit root= param References: <20080827183453.eb651f50.sfr@canb.auug.org.au> <200808292123.07246.bzolnier@gmail.com> <48B90E81.5060905@kernel.org> <200808311538.38918.bzolnier@gmail.com> <48BBCB62.4040309@kernel.org> <20080901111635.GN20055@kernel.dk> <48BBD01A.7000603@kernel.org> <20080901113059.GO20055@kernel.dk> In-Reply-To: <20080901113059.GO20055@kernel.dk> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Mon, 01 Sep 2008 11:39:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org DEBUG_BLOCK_EXT_DEVT shuffles SCSI and IDE device numbers and root device number set using rdev become meaningless. Root devices should be explicitly specified using textual names. Warn about it if root can't be found and DEBUG_BLOCK_EXT_DEVT is enabled. Also, add warning to the help text. Signed-off-by: Tejun Heo Cc: Bartlomiej Zolnierkiewicz --- I think distros should enable it for early alpha/betas to catch odd problems. Well, anyways, here's the updated version. Thanks. init/do_mounts.c | 4 ++++ lib/Kconfig.debug | 6 ++++++ 2 files changed, 10 insertions(+) Index: work/init/do_mounts.c =================================================================== --- work.orig/init/do_mounts.c +++ work/init/do_mounts.c @@ -263,6 +263,10 @@ retry: printk("Please append a correct \"root=\" boot option; here are the available partitions:\n"); printk_all_partitions(); +#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT + printk("DEBUG_BLOCK_EXT_DEVT is enabled, you need to specify " + "explicit textual name for \"root=\" boot option.\n"); +#endif panic("VFS: Unable to mount root fs on %s", b); } Index: work/lib/Kconfig.debug =================================================================== --- work.orig/lib/Kconfig.debug +++ work/lib/Kconfig.debug @@ -638,6 +638,12 @@ config DEBUG_BLOCK_EXT_DEVT userland code paths which assume predetermined contiguous device number allocation. + Note that turning on this debug option shuffles all the + device numbers for all IDE and SCSI devices including libata + ones, so root partition specified using device number + directly (via rdev or root=MAJ:MIN) won't work anymore. + Textual device names (root=/dev/sdXn) will continue to work. + Say N if you are unsure. config LKDTM