From: Eric Blake <eblake@redhat.com>
To: Max Reitz <mreitz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] qcow2: Switch L1 table in a single sequence
Date: Mon, 30 Sep 2013 11:48:32 -0600 [thread overview]
Message-ID: <5249B970.7060001@redhat.com> (raw)
In-Reply-To: <1380556641-26256-1-git-send-email-mreitz@redhat.com>
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On 09/30/2013 09:57 AM, Max Reitz wrote:
> Switching the L1 table in memory should be an atomic operation, as far
> as possible. Calling qcow2_free_clusters on the old L1 table on disk is
> not a good idea when the old L1 table is no longer valid and the address
> to the new one hasn't yet been written into the corresponding
> BDRVQcowState field. To be more specific, this can lead to segfaults due
> to qcow2_check_metadata_overlap trying to access the L1 table during the
> free operation.
>
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
> block/qcow2-cluster.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
Reviewed-by: Eric Blake <eblake@redhat.com>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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next prev parent reply other threads:[~2013-09-30 17:48 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-30 15:57 [Qemu-devel] [PATCH] qcow2: Switch L1 table in a single sequence Max Reitz
2013-09-30 17:48 ` Eric Blake [this message]
2013-10-01 9:12 ` Kevin Wolf
2013-10-02 13:38 ` Stefan Hajnoczi
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