At the end of last week, the German Interior Ministry announced that Greece and Germany have signed an agreement. The agreement states that anyone who has already applied for asylum in Greece (i.e. anyone with a Greek white card) and who is trying to enter Germany, can be returned directly to Greece within 48 hours of being caught at the German border. This only applies for asylum seekers that get caught at the border between Austria and Germany and not at any other borders between Germany and other countries. Also, unaccompanied minors will not be returned to Greece.
In return, Germany will process pending Dublin family reunification requests from Greece more quickly and seek to finish the backlog of cases by the end of 2018. Unfortunately, it remains unclear as to what exactly this means. Germany has also promised to re-examine certain family reunification cases, where the Greek authorities have found their rejection disputable.