Re: dm-verity setup on loop device

On 07/04/2022 11:40, Jasper Surmont wrote:
> While trying to understand the dm-verity code, I tried making a small
> verity setup. I created 1 readonly loop device and 1 non-readonly loop
> device. When I then try to create the verity target with the readonly
> as data device (not using veritysetup because I want to experiment on
> a low level), dmesg still says that the device is not in readonly
> mode.
> 
> Is it possible what I'm trying to achieve?

Yes, it should be possible.
(If you have device with Merkle-tree already prepared, if not, it will only
activate in failed state - but it will allow creation of the DM device.)

And if you post the exact command you are trying,
maybe we can show you where is the problem :-)

Both devices should be read only (dm-verity cannot be mapped for writes)
and I guess you need to call dmsetup with -r (--readonly) option.

Milan