ext4 and chattr ( change attributes ) 's - undo ( u ) option

This is an microsd ext4 card on a rooted Android, where I want to use busybox chattr -R +u /mypath I know what +u means but does anyone have an idea about how the undo option is implemented for ext4 and specifically in case my hardware to what extent undo will let me in datarecovery. If I use extundelete & ext4magic would these get back my data in case it's deleted by the app ? corollary to that if : -- ext4 does honor +u and other extended attributes any mount level option that will gimme a good chance of recovery in case of deletion ? -- what file system then does +u work with after all chattr is a linux / unix command there is a mention > ext_attr This feature enables the use of extended attributes. This feature is supported by ext2, ext3, and ext4. here I wondered if that op mount activate the +u attribute