From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from meiko.romanrm.net ([195.154.92.155]:37455 "EHLO meiko.romanrm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754174AbcATSql (ORCPT ); Wed, 20 Jan 2016 13:46:41 -0500 Date: Wed, 20 Jan 2016 23:46:38 +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: <20160120234638.39695c15@natsu> In-Reply-To: <569FC3C1.2000804@redhat.com> References: <20160120030223.22cc3ae0@natsu> <569EB653.9080700@redhat.com> <20160120040302.308f054e@natsu> <1185704624.11958670.1453278484410.JavaMail.zimbra@redhat.com> <20160120185810.2c566f98@natsu> <569FC3C1.2000804@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/DITwwXDIBfyrRFXqPM62JrP"; protocol="application/pgp-signature" Sender: linux-btrfs-owner@vger.kernel.org List-ID: --Sig_/DITwwXDIBfyrRFXqPM62JrP Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 20 Jan 2016 18:28:33 +0100 Paolo Bonzini wrote: > >> Also, can you find the value of the "FUA" file in sysfs (e.g. > >> with "cat /sys/block/sda/device/scsi_disk/*/FUA")? > >=20 > > It is 0 both in IDE and SCSI modes. >=20 > And in the host? On the host the backing block device for the host filesystem is an MD RAID6= , it does not have the FUA setting. For the actual sdX disks, it's all 0 as well. As I said this might be not KVM-specific, but rather a Btrfs-only related issue. That KVM with IDE doesn't show the problem, might be a coincidence s= ince as you mentioned it doesn't load the disks as heavily. If you're interested in my reproducer outside of KVM, I started a new threa= d: http://permalink.gmane.org/gmane.comp.file-systems.btrfs/52369 --=20 With respect, Roman --Sig_/DITwwXDIBfyrRFXqPM62JrP Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlaf1g4ACgkQTLKSvz+PZwicHwCeNmklGrC5qVrUDJibP0prakVN T0YAn0T6lRdCjCcFy0WSHCiVWTcyr0I0 =W2Ep -----END PGP SIGNATURE----- --Sig_/DITwwXDIBfyrRFXqPM62JrP--