From: "Richard W.M. Jones" <rjones@redhat.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: kwolf@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] qcow2, lazy_refcounts and killing qemu
Date: Fri, 5 Sep 2014 18:41:37 +0100 [thread overview]
Message-ID: <20140905174137.GI1302@redhat.com> (raw)
In-Reply-To: <20140905153951.GJ27649@stefanha-thinkpad.redhat.com>
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On Fri, Sep 05, 2014 at 04:39:51PM +0100, Stefan Hajnoczi wrote:
> Did you try older QEMU versions? I'm curious if this is something that
> crept in later or is fundamentally broken in lazy_refcounts=on.
At your prompting, I've done a bit more investigation.
I was basing my observations on qemu 2.1.0. However I tried my test
against qemu from git today and the bug has gone. Good!
For my entertainment, I bisected the problem, and the commit which
*fixes* it is:
commit 91af7014125895cc74141be6b60f3a3e882ed743
Author: Max Reitz <mreitz@redhat.com>
Date: Fri Jul 18 20:24:56 2014 +0200
block: Add bdrv_refresh_filename()
I didn't believe this either, but I have checked the result manually
and I'm pretty sure that whatever this commit does, it does end up
fixing the lazy_refcounts problem as a side-effect.
----------------------------------------------------------------------
I've updated the test script (attached), so you can now run it against
your own qemu, and also to improve the output.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-df lists disk usage of guests without needing to install any
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next prev parent reply other threads:[~2014-09-05 17:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-30 14:53 [Qemu-devel] qcow2, lazy_refcounts and killing qemu Richard W.M. Jones
2014-09-01 12:41 ` Greg Kurz
2014-09-01 13:07 ` Richard W.M. Jones
2014-09-01 14:19 ` Richard W.M. Jones
2014-09-01 14:23 ` Richard W.M. Jones
2014-09-01 14:30 ` Greg Kurz
2014-09-05 15:39 ` Stefan Hajnoczi
2014-09-05 17:41 ` Richard W.M. Jones [this message]
2014-09-08 7:16 ` Markus Armbruster
2014-09-08 18:29 ` Max Reitz
2014-09-08 9:57 ` Stefan Hajnoczi
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