How can I shrink a LUKS partition, what does `cryptsetup resize` do?

view full story

http://unix.stackexchange.com – I am in progress of resizing a LUKS encrypted partition that contains a single ext4 filesystem (no LVM or something). The cryptsetup FAQ recommends to remove the old partition and recreate it, but that sounds like wasting a lot time. Therefore I want to proceeed by manually, carefully resizing the partition. So far, I think that I need to do: Unmount the existing ext4 filesystem (e.g. by booting into a Live CD). If booting from a Live CD, mount the encrypted partition using cryptsetup luksOpen /dev/sdXY ExistingExt4 Resize the existing ext4 filesystem. cryptsetup resize /dev/mapper/Existing (HowTos)