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

[André Almeida]

Em 14/01/2026 03:26, Christoph Hellwig escreveu:
> On Wed, Jan 14, 2026 at 01:31:43AM -0300, André Almeida wrote:
> > Some filesystem, like btrfs, supports mounting cloned images, but assign
> > random UUIDs for them to avoid conflicts. This breaks overlayfs "index"
> > check, given that every time the same image is mounted, it get's
> > assigned a new UUID.
>
> ... and the fix is to not assign random uuid, but to assign a new uuid
> to the cloned image that is persisted.  That might need a new field
> to distintguish the stamped into the format uuid from the visible
> uuid like the xfs metauuid, but not hacks like this.

How can I create this non random and persisting UUID? I was thinking of 
doing some operation on top the original UUID, like a circular shift, 
some sort of rearrangement of the original value that we can always 
reproduce. Is this in the right direction do you think?