remodel from UC20 to UC22 with edge snapd fails on ubuntu-save

[Dimitri John Ledkov]

refreshed to snapd from edge, and attempting to remodel to UC22 pc model:

It fails with:

Update assets from gadget "pc" (156)

2023-09-12T09:53:10Z ERROR cannot prepare update for volume structure #4 ("ubuntu-save") on volume pc: structure 4 on volume pc does not have a writable mountpoint in order to update the filesystem content

Should we create a UC22 model with a UC22 gadget that doesn't have ubuntu-save?
Or should we somehow make ubuntu-save optional for upgrades?

[Dimitri John Ledkov (xnox)]

My UC20 system has ubuntu-save

$ mount | grep save
/dev/mapper/ubuntu-save-4c93e473-7631-4d36-b865-7461fa609d03 on /run/mnt/ubuntu-save type ext4 (rw,relatime)
/dev/mapper/ubuntu-save-4c93e473-7631-4d36-b865-7461fa609d03 on /var/lib/snapd/save type ext4 (rw,relatime)
/dev/mapper/ubuntu-save-4c93e473-7631-4d36-b865-7461fa609d03 on /writable/system-data/var/lib/snapd/save type ext4 (rw,relatime)

and it is encrypted.

Not sure what it means about "does not have a writable mountpoint"

Also I don't think there is any filesystem content to update either...

Not sure which mode it is booted in, maybe it is not mounted during that operation for some reason?

[Dimitri John Ledkov (xnox)]

i will check if this is because of encryption. and if unencrypted case works.

[Alfonso Sanchez-Beato (alfonsosanchezbeato)]

I have been able to reproduce, for the encrypted case. Unencrypted works fine.

[Alfonso Sanchez-Beato (alfonsosanchezbeato)]

Fix: https://github.com/snapcore/snapd/pull/13238