According to sources including the South China Morning Post, a China Eastern A330 has returned to Sydney safely after discovering a massive hole in the port side engine cowling.
There has not been any indication of what has caused the engine cowling to experience the disruption on the Shanghai-bound aircraft, nor how many passengers were on board. It appears that the aircraft has arrived safely on the ground in Sydney and is being examined at this time.
On a lighter note, please note the audio and transcription of the distress call:
— Flight (@flightorg) June 11, 2017
HT: @FlightOrg twitter team