Re: [PATCH 3/3] ovl: Use real disk UUID for origin file handles

[Christoph Hellwig]

On Thu, Jan 15, 2026 at 12:42:33PM -0300, André Almeida wrote:
>> So André, can you confirm this what you're worried about?  And btrfs
>> developers, I think the main problem is indeed that btrfs simply allows
>> mounting the same fsid twice.  Which is really fatal for anything using
>> the fsid/uuid, such NFS exports, mount by fs uuid or any sb->s_uuid user.
>>
>
> Yes, I'm would like to be able to mount two cloned btrfs images and to use 
> overlayfs with them. This is useful for SteamOS A/B partition scheme.

Then you'll really need to assign them different (persistent) fsids/uuids.