From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from meiko.romanrm.net ([195.154.92.155]:40871 "EHLO meiko.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932414AbcASXDJ (ORCPT ); Tue, 19 Jan 2016 18:03:09 -0500 Date: Wed, 20 Jan 2016 04:03:02 +0500 From: Roman Mamedov To: Paolo Bonzini Cc: linux-btrfs@vger.kernel.org, kvm@vger.kernel.org Subject: Re: Kernel 4.4.0 KVM guest on Btrfs locks up on snapshotting Message-ID: <20160120040302.308f054e@natsu> In-Reply-To: <569EB653.9080700@redhat.com> References: <20160120030223.22cc3ae0@natsu> <569EB653.9080700@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/nENwCuKKhzYVi.SkW5VIFZT"; protocol="application/pgp-signature" Sender: linux-btrfs-owner@vger.kernel.org List-ID: --Sig_/nENwCuKKhzYVi.SkW5VIFZT Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hello, On Tue, 19 Jan 2016 23:18:59 +0100 Paolo Bonzini wrote: > So this is kernel 4.4 on the host, and virtio-scsi in the guest. What > about virtio-blk in the guest? Tried with: -device virtio-blk-pci,drive=3Dhd,scsi=3Doff it locks up as well. In fact turns out it's not 100% lock-up, more like 50-80% chance. But it certainly happens if I trigger heavy disk activity in the guest: while true; do dd if=3D/dev/zero of=3Dzerofile count=3D1024 bs=3D1M; sync= ; done ...at the same time repeatedly snapshotting the subvolume on the host. Could not trigger it even once with IDE so far. > > -drive > > if=3Dnone,id=3Dhd,cache=3Dwriteback,aio=3Dthreads,format=3Draw,file=3D$= NAME.img,discard=3Dunmap,detect-zeroes=3Dunmap > > \ >=20 > So you're snapshotting the subvolume that includes $NAME.img? Yes --=20 With respect, Roman --Sig_/nENwCuKKhzYVi.SkW5VIFZT Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlaewKYACgkQTLKSvz+PZwiZKgCffrz2+Na7DWheWjSrt9gWQef1 6NQAnixZXnHB+1QvZ6JnmB+g+XDT6hQz =qfn8 -----END PGP SIGNATURE----- --Sig_/nENwCuKKhzYVi.SkW5VIFZT--