Ext4 FS has claimed 3% of partition space. Where has this gone and can I get it reclaimed? I have tried disabling Journals for the ext4 partition. Even this is not helping. Any other tricks I can try to get the space reclaimed other than reverting back to ext3?

$ lsb_release -cr 

Release:    12.04
Codename:   precise

df -hP |grep media

/dev/sda3        21G  430M   20G   3% /media/MAIL

/dev/sda2       148G  188M  148G   1% /media/DATA => if I move this to ext4 its claiming 2.4G 

/dev/sda3 on /media/MAIL type ext4 (rw,nosuid,nodev,uhelper=udisks)

/dev/sda2 on /media/DATA type ext3 (rw,nosuid,nodev,uhelper=udisks)

$ sudo tune2fs -l /dev/sda3 |grep 'Reserved block count'

Reserved block count:     0

$ sudo tune2fs -l /dev/sda2 |grep 'Reserved block count'

Reserved block count:     0

NO hidden files or directories

$ sudo du -ah *;pwd

16K lost+found
/media/MAIL