[Trisquel-users] trying to use losetup, ioctl tells me argument is invalid

[blade . vp2020]

hi
I try use losetup
to encrypt file system
but ioctl tells me argument is invalid
Code:
losetup -e aes-256 /dev/loop0 /dev/hda5
Password:

REPRODUCE ERROR:

ioctl: LOOP_SET_STATUS: Invalid argument

perhaps the bug should be for the kernel?

Or am I doing something wrong, but the way above worked always (tested on  
other distro)?????????????
???