Re: [PATCH 1/3] exportfs: Rename get_uuid() to get_disk_uuid()

[Christoph Hellwig <hch@lst.de>]

On Tue, Jan 13, 2026 at 10:10:28PM -0800, Darrick J. Wong wrote:
> On Wed, Jan 14, 2026 at 01:31:41AM -0300, André Almeida wrote:
> > To make clear which UUID is being returned, rename get_uuid() to
> > get_disk_uuid(). Expand the function documentation to note that this
> > function can be also used for filesystem that supports cloned devices
> > that might have different UUIDs for userspace tools, while having the
> > same UUID for internal usage.
> 
> I'm not sure what a "disk uuid" is -- XFS can store two of them in the
> ondisk superblock: the admin-modifiable one that blkid reports, and the
> secret one that's stamped in all the metadata and cannot change.

It isn't.  Totally independent of the rest of the discussion, the
get_uuid exportfs operation is not useful for anything but the original
pNFS block layout.  Which is actually pretty broken and should be slowly
phased out.

> IIRC XFS only shares the user-visible UUID, but they're both from the
> disk.   Also I'm not sure what a non-disk filesystem is supposed to
> provide here?

Yeah.