Comment # 43 on bug 1209457 from St���phane DESNEUX

Hi Neil,

Thanks for taking some time to investigate on this problem.

As I mentioned earlier, I captured the nfs conversation between my laptop (Leap
15.4, same client as before) and the QNAP NAS server (details in description).

As a summary:
* showmount works
* mount blocks indefinitely, as before. I stopped after 10mn.

Looking at the capture (mount_ls_umount_kernel_46.1.pcapng.gz versus
mount_ls_umount_kernel_55.3.pcapng.gz): everything is similar until we reach
request #82 on kernel .55.3. The call GETATTR with FSID,FS_Locations is sent
and the server replies with NFS4ERR_DELAY. This specific GETATTR call is not
present in the capture for kernel .46.1. Then the same sequence repeats
indefinitely every 15s.

Looking on the web, I found a very similar issue ~1 year ago:
https://bugzilla.redhat.com/show_bug.cgi?id=2055362

The conclusion was: updating QNAP NFS Server could help... I'll do this and
report.

But in any case, even if the NFS Server doesn't behave correctly, the client
shouldn't block indefinitely. This is a major issue to be solved on client side
IMO.