The old code detected an overlapping allocation even when the
allocations didn't actually overlap, but were only adjacent.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This one is a bit more interesting. The COW operation isn't performed
completely synchronously, and therefore dependencies must be handled
correctly when multiple requests write to the same unallocated cluster.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>