6db39ae2e2
Since coroutine operation is now mandatory, convert both bdrv_discard implementations to coroutines. For qcow2, this means taking the lock around the operation. raw-posix remains synchronous. The bdrv_discard callback is then unused and can be eliminated. Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>