anyfs-tools allows you to recover and convert
filesystems while using minimal extra disk space.
Unlike other recovery tools, anyfs-tools doesn't
copy all the files found on other disks (or
partitions), but only saves information about the
location of the file blocks to an external inode
table. After recovery, a user may mount the
damaged filesystem with anyfs and the external
inode table and then interact with all recovered
files with any program.