Therefore, you should always make backups before doing any repartitioning.
"Debian GNU/Linux: Guide to Installation and Usage"
John Goerzen and Ossama Othman
It is important that you do as little as possible between the data movement and repartitioning to minimize the chance of a file being written near the end of the partition as this will decrease the amount of space you can take from the partition.
"Debian GNU/Linux: Guide to Installation and Usage"
John Goerzen and Ossama Othman