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From: Roman Mamedov <rm@romanrm.net>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: linux-btrfs@vger.kernel.org, kvm@vger.kernel.org
Subject: Re: Kernel 4.4.0 KVM guest on Btrfs locks up on snapshotting
Date: Wed, 20 Jan 2016 04:03:02 +0500	[thread overview]
Message-ID: <20160120040302.308f054e@natsu> (raw)
In-Reply-To: <569EB653.9080700@redhat.com>

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Hello,

On Tue, 19 Jan 2016 23:18:59 +0100
Paolo Bonzini <pbonzini@redhat.com> 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=hd,scsi=off

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=/dev/zero of=zerofile count=1024 bs=1M; 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=none,id=hd,cache=writeback,aio=threads,format=raw,file=$NAME.img,discard=unmap,detect-zeroes=unmap
> > \
> 
> So you're snapshotting the subvolume that includes $NAME.img?

Yes


-- 
With respect,
Roman

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  reply	other threads:[~2016-01-19 23:03 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-19 22:02 Kernel 4.4.0 KVM guest on Btrfs locks up on snapshotting Roman Mamedov
2016-01-19 22:18 ` Paolo Bonzini
2016-01-19 23:03   ` Roman Mamedov [this message]
2016-01-20  8:28     ` Paolo Bonzini
2016-01-20 13:58       ` Roman Mamedov
2016-01-20 17:28         ` Paolo Bonzini
2016-01-20 18:46           ` Roman Mamedov
2016-01-20 20:38             ` Paolo Bonzini
2016-01-20  0:19 ` Liu Bo
2016-01-20  5:08   ` Roman Mamedov
2016-01-20 11:34     ` Paolo Bonzini
2016-01-20 15:08       ` Roman Mamedov

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