[HADOOP-14942] DistCp#cleanup() should check whether jobFS is null

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 2.9.0, 3.0.0
• Target Version/s: 3.0.0
• Assignee: Andras Bokor
• Reporter: Ted Yu
• Created: 11/Oct/17 00:41
• Updated: 20/Oct/17 22:01
• Resolved: 20/Oct/17 21:29

Description

Over in HBASE-18975, we observed the following:

2017-10-10 17:22:53,211 DEBUG [main] mapreduce.MapReduceBackupCopyJob(313): Doing COPY_TYPE_DISTCP
2017-10-10 17:22:53,272 DEBUG [main] mapreduce.MapReduceBackupCopyJob(322): DistCp options: [hdfs://localhost:55247/backupUT/.tmp/backup_1507681285309, hdfs://localhost:55247/   backupUT]
2017-10-10 17:22:53,283 ERROR [main] tools.DistCp(167): Exception encountered
java.lang.reflect.InvocationTargetException
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  at java.lang.reflect.Method.invoke(Method.java:498)
  at org.apache.hadoop.hbase.backup.mapreduce.MapReduceBackupCopyJob$BackupDistCp.execute(MapReduceBackupCopyJob.java:234)
  at org.apache.hadoop.tools.DistCp.run(DistCp.java:153)
  at org.apache.hadoop.hbase.backup.mapreduce.MapReduceBackupCopyJob.copy(MapReduceBackupCopyJob.java:331)
  at org.apache.hadoop.hbase.backup.impl.IncrementalTableBackupClient.incrementalCopyHFiles(IncrementalTableBackupClient.java:286)
...
Caused by: java.lang.NullPointerException
  at org.apache.hadoop.tools.DistCp.cleanup(DistCp.java:460)
  ... 45 more

NullPointerException came from second line below:

      if (metaFolder == null) return;

      jobFS.delete(metaFolder, true);

in which case jobFS was null.
A check against null should be added.