[dm-crypt] Cryptsetup-reencrypt failing with error with option --new reduce-device-size

Milan Broz gmazyland at gmail.com
Fri Jun 20 15:20:55 CEST 2014

On 06/20/2014 02:36 PM, Abhrajyoti Kirtania wrote:
> cryptsetup-reencrypt /dev/sda8 --new --reduce-device-size 1024

> Cannot wipe header on device /dev/loop0. if i pass --reduce-device-size as 1024.
> But if i pass this size as 4096 then getting the error as "Device /dev/loop0 is too small."

New LUKS device header needs more than 1024 or 4096 bytes - you need space for keyslots.
Try reduce device size by 4 Megabytes (and do not forget to reduce fs first):

cryptsetup-reencrypt /dev/sda8 --new --reduce-device-size 4M

and it should work.

I will probably add more descriptive error message here, it is really cryptic.


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