Re: [Qemu-devel] [RFC V6 29/33] qcow2: Do not overwrite existing entries with QCOW_OFLAG_COPIED.

[Stefan Hajnoczi]

On Wed, Feb 06, 2013 at 01:32:02PM +0100, Benoît Canet wrote:
> In the case of a race condition between two writes a l2 entry can be written
> without QCOW_OFLAG_COPIED before the first write fill it.
> This patch simply check if the l2 entry has the correct offset without
> QCOW_OFLAG_COPIED and do nothing.
> 
> Signed-off-by: Benoit Canet <address@hidden>
> ---
>  block/qcow2-cluster.c |    5 +++++
>  1 file changed, 5 insertions(+)

Is this a general qcow2 bug (without deduplication)?

I thought there is L2Meta wait code in qcow2_co_writev() that prevents
overlapping writes from executing at the same time?