On Fri, Jul 9, 2021 at 1:34 AM Ulli Horlacher
[off-list ref] wrote:

root@tsmsrvj:/# du -s /nfs/localhost/fex
du: WARNING: Circular directory structure.
This almost certainly means that you have a corrupted file system.
NOTIFY YOUR SYSTEM MANAGER.
The following directory is part of the cycle:
  /nfs/localhost/fex/spool

What do you get for:

btrfs subvolume list -to /nfs/localhost/fex


-- 
Chris Murphy