From: Dave Chinner Subject: Re: ext4 error when testing virtio-scsi & vhost-scsi Date: Wed, 13 Jul 2016 09:03:56 +1000 Message-ID: <20160712230356.GJ1922@dastard> References: <20160712164324.GC11020@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Zhangfei Gao , kvm@vger.kernel.org, qemu-devel@nongnu.org, target-devel@vger.kernel.org, linux-ext4@vger.kernel.org To: Theodore Ts'o Return-path: Content-Disposition: inline In-Reply-To: <20160712164324.GC11020@thunk.org> Sender: target-devel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Tue, Jul 12, 2016 at 12:43:24PM -0400, Theodore Ts'o wrote: > On Tue, Jul 12, 2016 at 03:14:38PM +0800, Zhangfei Gao wrote: > > Some update: > > > > If test with ext2, no problem in iblock. > > If test with ext4, ext4_mb_generate_buddy reported error in the > > removing files after reboot. > > > > > > root@(none)$ rm test > > [ 21.006549] EXT4-fs error (device sda): ext4_mb_generate_buddy:758: group 18 > > , block bitmap and bg descriptor inconsistent: 26464 vs 25600 free clusters > > [ 21.008249] JBD2: Spotted dirty metadata buffer (dev = sda, blocknr = 0). Th > > ere's a risk of filesystem corruption in case of system crash. > > > > Any special notes of using ext4 in qemu? > > Ext4 has more runtime consistency checking than ext2. So just because > ext4 complains doesn't mean that there isn't a problem with the file > system; it just means that ext4 is more likely to notice before you > lose user data. > > So if you test with ext2, try running e2fsck afterwards, to make sure > the file system is consistent. > > Given that I'm reguarly testing ext4 using kvm, and I haven't seen > anything like this in a very long time, I suspect the problemb is with > your SCSI code, and not with ext4. It's the same error I reported yesterday for ext3 on 4.7-rc6 when rebooting a VM after it hung. Cheers, Dave. -- Dave Chinner david@fromorbit.com