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Date: Fri, 12 Oct 2012 10:28:31 +0200
From: Stefan Hajnoczi <stefanha@gmail.com>
Message-ID: <20121012082831.GA14822@stefanha-thinkpad.redhat.com>
References: <1349962403.4696.51.camel@storm>
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In-Reply-To: <1349962403.4696.51.camel@storm>
Subject: Re: [Qemu-devel] Silent filesystem/qcow2 corruptions with
 qemu-kvm-1.0 and 1.1.1
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To: Tiziano =?iso-8859-1?Q?M=FCller?= <tiziano.mueller@stepping-stone.ch>
Cc: qemu-devel <qemu-devel@nongnu.org>

On Thu, Oct 11, 2012 at 03:33:23PM +0200, Tiziano Müller wrote:
> One test case was:
> * xfs_repair /dev/vda2 -> corruptions found and fixed
> * xfs_repair /dev/vda2 -> no corruptions found

>>From here...

> * mount /dev/vda2 /mnt/something
> * find /mnt/something > /dev/null
> * umount /mnt/something

...to here is mostly read-only.

> * xfs_repair /dev/vda2 -> corruptions found again

And yet corruptions are reported inside the guest!

Can you retry with "mount -o ro" just for sanity?  If you still see
corruptions when the device was mounted read-only, then perhaps the
mount/find/umount sequence itself is innocent.

Have you tried raw image files?  In other words, do you know that the
corruption only happens with qcow2?

Stefan