From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752766Ab1FMMoV (ORCPT ); Mon, 13 Jun 2011 08:44:21 -0400 Received: from 0122700014.0.fullrate.dk ([95.166.99.235]:44937 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751381Ab1FMMoU (ORCPT ); Mon, 13 Jun 2011 08:44:20 -0400 Message-ID: <4DF60622.7020804@kernel.dk> Date: Mon, 13 Jun 2011 14:44:18 +0200 From: Jens Axboe MIME-Version: 1.0 To: Tejun Heo CC: linux-kernel@vger.kernel.org, stable@kernel.org, avillaci@ceibo.fiec.espol.edu.ec Subject: Re: [PATCH] block: use the passed in @bdev when claiming if partno is zero References: <20110613104440.GB16021@htj.dyndns.org> In-Reply-To: <20110613104440.GB16021@htj.dyndns.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011-06-13 12:44, Tejun Heo wrote: > 6b4517a791 (block: implement bd_claiming and claiming block) > introduced claiming block to support O_EXCL blkdev opens properly. > > bd_start_claiming() looks up the part 0 bdev and starts claiming > block. The function assumed that there is only one part 0 bdev and > always used bdget_disk(disk, 0) to look it up; unfortunately, this > isn't true for some drivers (floppy) which use multiple block devices > to denote different operating parameters for the same physical device. > There can be multiple part 0 bdev's for the same device number. > > This incorrect assumption caused the wrong bdev to be used during > claiming leading to unbalanced bd_holders as reported in the following > bug. > > https://bugzilla.kernel.org/show_bug.cgi?id=28522 > > This patch updates bd_start_claiming() such that it uses the bdev > specified as argument if its partno is zero. > > Note that this means that different bdev's can be used for the same > device and O_EXCL check can be effectively bypassed. It has always > been broken that way and floppy is fortunately on its way out. Leave > that breakage alone. Thanks, applied for 3.0. -- Jens Axboe