[pve-devel] [PATCH container v2 03/11] alloc_disk: fail fast if storage does not support content type rootdir

[Daniel Kral]

On 2/20/25 13:15, Fiona Ebner wrote:
> I also noticed that we have no check against starting a container with
> volumes on a storage that does not support 'rootdir'. We have such a
> check for VMs IIRC. Prohibiting that would also be good, but maybe
> something for PVE 9 where we can also check for misconfigured
> containers/storages via the pve8to9 script up front so users can adapt.

I'm preparing the v3 for this now, but I just noticed there actually is 
a assertion for this since e6da5357cc ("fix #3421: allow custom storage 
plugins to support rootfs") if I'm not missing something here in 
__mountpoint_mount(...).

What I don't yet understand is why there is no similar check for this in 
__mountpoint_mount for subvolumes, e.g. I can't start the container if I 
have a mountpoint on a directory storage without 'rootdir' support, but 
I can do so if the mountpoint is on a zfs pool without 'rootdir' support.

Since starting the container results in

run_buffer: 571 Script exited with status 25
lxc_init: 845 Failed to run lxc.hook.pre-start for container "101"
__lxc_start: 2034 Failed to initialize container "101"
TASK ERROR: startup for container '101' failed

for the WebGUI, I'll try to squeeze in a patch to make the error message 
a little more readable if there's something going wrong when mounting.

---

On another note, I've also noticed that if the root disk / mountpoint is 
already on a storage which does not support 'rootdir', the user is 
unable to move it to another storage... Shouldn't we allow users to do 
that so they can easily move out error states? Either way, this can be a 
follow-up anway, so no need to make this patch series any longer.