From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: linux-next: Tree for August 27 Date: Fri, 29 Aug 2008 21:23:07 +0200 Message-ID: <200808292123.07246.bzolnier@gmail.com> References: <20080827183453.eb651f50.sfr@canb.auug.org.au> <48B7C361.9070008@kernel.org> <20080829094249.GQ20055@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from nf-out-0910.google.com ([64.233.182.184]:62248 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750961AbYH2TZ4 (ORCPT ); Fri, 29 Aug 2008 15:25:56 -0400 Received: by nf-out-0910.google.com with SMTP id d3so250487nfc.21 for ; Fri, 29 Aug 2008 12:25:55 -0700 (PDT) In-Reply-To: <20080829094249.GQ20055@kernel.dk> Content-Disposition: inline Sender: linux-next-owner@vger.kernel.org List-ID: To: Jens Axboe Cc: Tejun Heo , Stephen Rothwell , linux-next@vger.kernel.org, LKML , Ingo Molnar , dm-devel@redhat.com Hi, On Friday 29 August 2008, Jens Axboe wrote: > On Fri, Aug 29 2008, Tejun Heo wrote: > > Jens Axboe wrote: > > >> On the somehow related topic - CONFIG_DEBUG_BLOCK_EXT_DEVT which is > > >> introduced by commit 3e5ba59bbab878f60b8b87004ac55a464bddc819 ("block: > > >> implement CONFIG_DEBUG_BLOCK_EXT_DEVT") is way too intrusive to be > > >> enabled by default if CONFIG_DEBUG_KERNEL is set as it easily results > > >> in no longer bootable systems (+ help entry for the new option says > > >> "Say N if you are unsure."). > > >> > > >> Tejun/Jens: please consider changing this. > > > > > > I have change the default to 'n' for now. > > > > Hmmm... it broke booting? Bart, can you please elaborate a bit what got > > broken? Did it fail to locate the root partition or were you using > > static device nodes? > > It works fine for me, fwiw. It fails to locate the root partition if you are using the default root device on x86 (the one hard-wired into bzImage, it uses hard-coded 8-bit major/minor numbers). Now I see that the issue is easily fixed by passing the root device name with "root=" (since it will figure out the actual major/minor numbers later) and that the default root device is said to be deprecated according to Documentation/x86/boot.txt (OTOH there is no warning at all that it is deprecated and that you should be using "root=" so I'm not convinced that I'm the only one who would hit the unfortunate combination). Actually it seems that CONFIG_DEBUG_BLOCK_EXT_DEVT introduction (which I think is a nice step forward) is a good oportunity to put the deprecation of the default root device further, i.e. it may be worth to hook the default root device check and/or CONFIG_DEBUG_BLOCK_EXT_DEVT one into mount_block_root(). Thanks, Bart