How to get checksum data integrity on ext4?

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http://serverfault.com – On file systems like btrfs you can preform a scrub, which will go though all the data to see if the data still matches the file system checksum. I would like to check the data on ext4 if it is correct before a backup. Question ext4 doesn't have file system checksum, but can something similar be made? (HowTos)