Description
For most operations, the 'dst' is null, add checking before logging the 'dst' information in FSNamesystemAuditLogger
2020-04-03 16:34:40,021 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem.audit: allowed=true ugi=user (auth:SIMPLE) ip=/127.0.0.1 cmd=listStatus src=/ dst=null perm=null proto=rpc 2020-04-03 16:35:16,329 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem.audit: allowed=true ugi=user (auth:SIMPLE) ip=/127.0.0.1 cmd=getfileinfo src=/ dst=null perm=null proto=rpc 2020-04-03 16:35:16,362 INFO org.apache.hadoop.hdfs.server.namenode.FSNamesystem.audit: allowed=true ugi=user (auth:SIMPLE) ip=/127.0.0.1 cmd=mkdirs src=/user dst=null perm=yang:supergroup:rwxr-xr-x proto=rpc