code: static long getFreeSpace(final File fileInFs) {
  		try {
  			long result = (long) getInstance().doPrivileged(new PrivilegedAction<Long>() {
  				public Long run() {
  					return fileInFs.getFreeSpace() ;
  				}
  			});
  			return result ;
  		} catch (SecurityException se) {
  			return -1 ;
  		}
  	}
docs: Returns free space on a file system containing the passed in file