I have reported the bug also on the btrfs mailing list. They say, it is a bug of the nfs server, which get confused about btrfs snapshots.
As a consequence I cannot use (any more) btrfs on the Ubuntu 20.04 nfs server (Ubuntu 18.04 is ok): root@tsmsrvj:~# mount | grep data /dev/sdb1 on /data type btrfs (rw,relatime,space_cache,user_subvol_rm_allowed,subvolid=5,subvol=/) localhost:/data/fex on /nfs/localhost/fex type nfs4 (rw,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=127.0.0.1,local_lock=none,addr=127.0.0.1) root@tsmsrvj:~# ls -R /nfs/localhost/fex | wc ls: /nfs/localhost/fex/spool: not listing already-listed directory -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1918599 Title: "File system loop detected" with btrfs over NFS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/1918599/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
