OCI: Prevent tmpfs mounts in config.json from overriding own mounts

[DanielAdolfsson]

Right now, it seems like our provided devices (mounts) are added before mounts defined in config.json.
This makes it so any tmpfs mounts inside config.json overwrites the mount provided by the user (if any).
Some images seem to set up a tmpfs mounts for certain volumes in case the user doesn't bind it to anything?

Maybe the tmpfs mounts provided by the oci image could be set up before the devices?

[stgraber]

Can you provide a reproducer for this?

The logic certainly is supposed to skip mounting on paths that are already handled by a device.

[DanielAdolfsson]

The particular image I was using is docker:teamspeak .

incus create docker:teamspeak  teamspeak
incus config device add teamspeak teamspeak_data disk source=./data path=/var/ts3server
incus start teamspeak --console

I did, however, notice that the mount destination inside config.json is /var/ts3server/, and I used path /var/ts3server. Note the ending /. Once I amended my device add to also include the ending /, it started working.

Maybe the paths should be normalized before they are used.

[stgraber]

Ah yeah, it'd be pretty likely that we're not normalizing the paths before comparison, explaining what you're seeing.