Many articles on the Internet are introduced ext3 or 2, under the ext4 you can try extundelete This software, I am in the Ubuntu 11.04 test, the data perfect recovery.
Suppose the deleted file is located in the/media/backup, and the mounted device is/DEV/SDA3.
First, mount the current disk again.
Then install the Extundelete dependent package,
sudo aptitude install e2fsprogs E2fslibs-dev
Download Extundelete, unzip Extundelete, run three strides
sudo make install
You can extundelete--help look at the usage, or simply restore Extundelete/dev/sda3--restore-all Note that the restored file is located in the recovered_files where the software folder is installed.