fstransform is a tool to change a file-system from one format to another. For example, it can change from jfs, xfs, or reiser to ext2, ext3, or ext4. It works in-place and without the need for backup. It currently has been tested on Linux only. It uses a sparse file to create the new file-system image, moves all the files of the existing file-system into it, then remaps the sparse file to the original partition.