recover deleted data from hdfs
This could be an easy fix if you have set the fs.trash.interval > 1. If this is true, HDFS's trash option is enabled, and your files should be located in the trash directory. By default, this directory is located at /user/X/.Trash.
Otherwise, your best option is probably to find and use a data recovery tool. Some quick Googling turned up this cross-platform tool available under GNU licensing that runs from the terminal: http://www.cgsecurity.org/wiki/PhotoRec. It works on many different types of file systems, and it's possible it may work for HDFS.