Requirements
  
   To use xattr, you will need libattr installed. It is available
   at » http://oss.sgi.com/projects/xfs/.
  
  Note: 
   
    These functions only work on filesystems that support extended 
    attributes, and have them enabled at mount time. Some common
    filesystems that support extended attributes are ext2, ext3,
    reiserfs, jfs, and xfs.