On 03/11/2014 08:15 AM, Kevin Wolf wrote:
> qcow2_open() causes writes when repairing an image with the dirty flag
> set and when clearing autoclear flags. It shouldn't do this when another
> qemu instance is still actively working on this image file.
> 
> One effect of the bug is that images may have a cleared dirty flag while
> the migration source host still has it in use with lazy refcounts
> enabled, so refcounts are not accurate and the dirty flag must remain
> set.
> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  block/qcow2.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org