[pve-devel] [PATCH container] fix #5907: ignore conflicting mount options for read-only mounts

[Daniel Kral]

On 11/25/24 14:09, Filip Schauer wrote:
> When mounting volumes as read-only, certain mount options like
> "discard", "lazytime", and "noatime" are either ignored or can cause the
> mount to fail. For example, attempting to mount with "-t zfs" and
> "-o ro,discard" leads to an error: filesystem cannot be mounted due to
> invalid option 'discard'.
> 
> This commit ensures that only valid mount options, such as "nodev",
> "noexec", and "nosuid", are applied to read-only mounts, avoiding
> potential mount failures.
> 
> Signed-off-by: Filip Schauer <f.schauer at proxmox.com>

I could reproduce the issue when backing up a container with at least 
one root disk or mountpoint, which has at least the mount option 
"discard" applied, and backing it up to a PBS instance (to stay close to 
the bug report I used v3.2.10-1 for this), while all images were stored 
on a ZFS pool.

After applying the patch, the container could be backed up to the same 
PBS instance without any trouble.

Reviewed-by: Daniel Kral <d.kral at proxmox.com>
Tested-by: Daniel Kral <d.kral at proxmox.com>