From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f52.google.com ([74.125.82.52]:36527 "EHLO mail-wm0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934015AbcATR2h (ORCPT ); Wed, 20 Jan 2016 12:28:37 -0500 Subject: Re: Kernel 4.4.0 KVM guest on Btrfs locks up on snapshotting To: Roman Mamedov References: <20160120030223.22cc3ae0@natsu> <569EB653.9080700@redhat.com> <20160120040302.308f054e@natsu> <1185704624.11958670.1453278484410.JavaMail.zimbra@redhat.com> <20160120185810.2c566f98@natsu> Cc: linux-btrfs@vger.kernel.org, kvm@vger.kernel.org From: Paolo Bonzini Message-ID: <569FC3C1.2000804@redhat.com> Date: Wed, 20 Jan 2016 18:28:33 +0100 MIME-Version: 1.0 In-Reply-To: <20160120185810.2c566f98@natsu> Content-Type: text/plain; charset=windows-1252 Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 20/01/2016 14:58, Roman Mamedov wrote: > On Wed, 20 Jan 2016 03:28:04 -0500 (EST) Paolo Bonzini > wrote: > >> Can you reproduce it on the host without QEMU in the middle? > > I did not try to stress-test this on purpose yet, but this is an > actively used system which is snapshotting its /home, VMs and root > subvolumes every hour, so far no lock-ups of any other application > than KVM, and with KVM it's trivially easy to hit, in fact first > two lockups occured in the first two hours of using the kernel > 4.4.0 at the hourly snapshots... > >> Also, can you find the value of the "FUA" file in sysfs (e.g. >> with "cat /sys/block/sda/device/scsi_disk/*/FUA")? > > It is 0 both in IDE and SCSI modes. And in the host? Paolo