From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: ext4fs error "ext4_mb_generate_buddy:741:group 16, 8160 clusters in bitmap, 4064 in gd" (with repro) Date: Thu, 16 Aug 2012 16:00:32 -0400 Message-ID: <20120816200032.GE31346@thunk.org> References: <50238A29.3060808@redhat.com> <20120809170640.GA6607@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Paolo Bonzini , "Linux Kernel Mailinlinux-ext4@vger.kernel.orgg List" , linux-ext4@vger.kernel.org To: =?utf-8?B?THVrw6HFoQ==?= Czerner Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Thu, Aug 16, 2012 at 04:28:07PM +0200, Luk=C3=A1=C5=A1 Czerner wrote= : >=20 > After a little bit of tracing with the systemtap and blktrace ext4 > does not seem to be doing anything wrong and yet we get part of the > block bitmap trimmed. This lead me to the scsi_debug driver itself > and indeed it seems that we have off-by-one bug there in the > unamp_region() which is causing the problem. Thanks for finding this --- I was getting scared that ext4 users were losing data in production. It's good to know it was just a bug in the scsi_debug driver. - Ted