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

[Christoph Hellwig]

On Thu, Jan 15, 2026 at 03:55:15PM -0300, André Almeida wrote:
>> Is there any guarantee that file handles are relevant and point to the
>> same objects?
>>
>> The whole point of the overlayfs index feature is that overlayfs inodes
>> can have a unique id across copy-up.
>>
>> Please explain in more details exactly which overlayfs setup you are
>> trying to do with index feature.
>>
>
> The problem happens _before_ switching from A to B, it happens when trying 
> to install the same image from A on B.
>
> During the image installation process, while running in A, the B image will 
> be mounted more than once for some setup steps, and overlayfs is used for 
> this. Because A have the same UUID, each time B is remouted will get a new 
> UUID and then the installation scripts fails mounting the image.

It sounds like the 'clones' really need different persistent uuids. Or
do you also have a requirement that the two images have the same ID,
which would require a noouid-like option and extremely careful handling.