This problem seems to have been solved. I believe that the issue was a misconfiguration of the NFS server. I had:

/home/rikiheck/files           192.168.1.0/24(rw,sync,no_subtree_check,fsid=0)
/home/nancy/files              192.168.1.0/24(rw,sync,no_subtree_check)
/home/photos                   192.168.1.0/24(rw,sync,no_subtree_check)
/multi                         192.168.1.0/24(rw,sync,no_subtree_check)
/git                           192.168.1.0/24(rw,sync,no_subtree_check)

But /home/rikiheck/files was an ordinary directory that I want to export, not the root for NFSv4. It was being mounted as NFSv3 (trying to mount with nfs4 would fail). But I'm guessing that it was being treated inconsistently between the client and the server. Removing the 'fsid=0' tag solved the problem. It's still a bit of a mystery what exactly the firewall was blocking, but it wasn't a firewall problem, in the end.

Thanks to everyone who offered suggestions and advice, especially Ed Greshko.

Probably I will take the opportunity to move anyway to NFSv4, now that I've done all this reading about how to do that!

Riki



On 11/25/20 4:55 PM, Richard Kimberly Heck wrote:
On 11/25/20 4:28 PM, Richard Kimberly Heck wrote:
On 11/25/20 12:56 PM, Ed Greshko wrote:
On 25/11/2020 22:51, Richard Kimberly Heck wrote:

I can mount fine. The problem is that various programs (LyX, LibreOffice) freeze when attempting to open files on those filesystems. In LyX, I was able to trace the problem to a call to lockd, which never returns. So it seems there is some problem with file locking, which it was suggested involved some firewall problem. Which it does, since disabling the firewall on the server solves the problem. (There's no firewall on the client.)

OK, sorry, I was only thinking about the initial post.

I tested and found some problems opening a file with LibreOffice in "edit" mode when using NFS-v3.
It would only open "read only".  Get a message from lockd that user is "unknown".  Too early in my
AM to track this down.  It maybe related to idmapd.  Will see if I can find the cause later today.

Thanks for the help. It's much appreciated.

Just to clarify: Stopping the firewall solves my problem.

One more piece: I tried using rpcdebug to see if there were any error messages on the server. Nothing, at least with 'rpcdebug -m nfsd -s auth -s lockd -s fileop'. I also tried 'rpcdebug -m nlm -s all'. Again nothing.

On the client, I tried 'rpcdebug -m nlm -s all'. That produced:

Nov 25 16:52:56 rkhstudy systemd[1540]: Started LibreOffice Writer - Word Processor.
Nov 25 16:52:57 rkhstudy kernel: lockd: get host 192.168.1.2
Nov 25 16:52:57 rkhstudy kernel: lockd: get host 192.168.1.2
Nov 25 16:52:57 rkhstudy kernel: lockd: nsm_monitor(192.168.1.2)
Nov 25 16:52:57 rkhstudy kernel: lockd: call procedure 2 on 192.168.1.2
Nov 25 16:52:57 rkhstudy kernel: lockd: nlm_bind_host 192.168.1.2 (192.168.1.2)
Nov 25 16:52:57 rkhstudy kernel: lockd: next rebind in 60000 jiffies
Nov 25 16:52:57 rkhstudy kernel: lockd: server 192.168.1.2 not responding, still trying

It seems like it must be a firewall issue. But nothing has changed on the server (except my enabling more things on the firewall since all this started).

Riki