From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752097AbYIBKg6 (ORCPT ); Tue, 2 Sep 2008 06:36:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751178AbYIBKgt (ORCPT ); Tue, 2 Sep 2008 06:36:49 -0400 Received: from g4t0015.houston.hp.com ([15.201.24.18]:2962 "EHLO g4t0015.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751121AbYIBKgs (ORCPT ); Tue, 2 Sep 2008 06:36:48 -0400 Message-ID: <48BD173B.3090600@hp.com> Date: Tue, 02 Sep 2008 06:36:43 -0400 From: "Alan D. Brunelle" User-Agent: Thunderbird 2.0.0.16 (X11/20080724) MIME-Version: 1.0 To: device-mapper development CC: "linux-kernel@vger.kernel.org" , Jens Axboe , tj@kernel.org Subject: Problem w/ CONFIG_DEBUG_BLOCK_EXT_DEVT Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I have found two problems in LVM2/DM w/ a potential new "experimental feature" in 2.6.28: CONFIG_DEBUG_BLOCK_EXT_DEVT (this is from Jens Axboe's origin/for-2.6.28 git branch) "Conventionally, block device numbers are allocated from predetermined contiguous area. However, extended block area may introduce non-contiguous block device numbers. This option forces most block device numbers to be allocated from the extended space and spreads them to discover kernel or userland code paths which assume predetermined contiguous device number allocation." W/ LVM2 & DM there are (at least) two issues: (1) Device major numbers for some reason are /not/ being entered correctly into /proc/devices -- w/ CONFIG_DEBUG_BLOCK_EXT_DEVT=y I am seeing some devices w/ major "259" (a SATA controller) but no entry in /proc/devices. LVM2/DM will not find the entry in /proc/devices, and not allow any device w/ that major to be used with LVM commands. (2) Device minor numbers can be quite large, and the 10-character limits in dm/lib/libdm-deptree.c are too small. Alan