I do not understand why creating a linear device and then trying to create another linear device on top of it fails. 1. Creating a linear device over loop1: =========================== dmsetup create linear_loop1 /tmp/linear_loop1 cat /tmp/linear_loop1 0 1000 linear /dev/loop1 0 2. Then creating another linear device over this linear device: ============================================= dmsetup create linear_loop2 /tmp/linear_loop2 device-mapper: reload ioctl failed: Invalid argument Command failed cat /tmp/klinear_loop2 0 1000 linear /dev/linear_loop1 0 Could you please explain what am I doing wrong?