[Qemu-devel] Re: [PATCH] qcow2/virtio corruption: Don't allocate the same cluster twice

[Kevin Wolf]

Avi Kivity schrieb:
> What happens if the second request completes before the first?  Then, 
> when the first request completes, alloc_cluster_link_l2() will call 
> copy_clusters() and overwrite the second request.

Ouch, you're right. I should not only check if the image is consistent,
but also if the data survives.

Will fix that tomorrow.

> Also, the second request now depends on the first to update its 
> metadata.  But if the first request fail, it will not update its 
> metadata, and the second request will complete without error and also 
> without updating its metadata.

Hm, right. Need to think about this...

Kevin