As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED SMOKE IN THE CABIN AT FL 200 FOLLOWED BY A LAV SMOKE WARNING. THEY ALSO REPORTED SMOKE IN THE COCKPIT. MAINTENANCE INSPECTED AND REPLACED THE NR 1 ENGINE. OPERATIONAL CHECKS WERE GOOD. THE NR 4 CARBON SEAL WAS FOUND DETERIORATED CAUSING OIL TO LEAK BY.