Run "hdfs groups xdl3" ... this will show you the hdfs groups associated with that user. If xdl3 is not in the hadoop group in hdfs, then it will not be able to write under that directory.
To sync hdfs group mappings with linux group mappings:
1. Run "sudo useradd <username> -g <hadoop_gid>" on all 3 hadoop servers
2. Run "hdfs dfsadmin -refreshUserToGroupsMappings" on one of the servers
3. Run "hdfs groups xdl3" to view the change
Hope this helps