[Bug 1340451] Re: nfs client hangs when nlockmgr service at rpcbind refuses connection

[Steve Langasek]

If your server is misconfigured such that the RPC calls will fail, how
should the client know that it's not a transient error?

Per the nfs(5) manpage, if you want NFS calls to be interruptable, you
can use the non-default 'intr' option.  If you want NFS calls to
eventually time out rather than being retried indefinitely, you can use
the non-default 'soft' option.

I don't think the behavior you're describing here is a bug, just the
expected default behavior.

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to nfs-utils in Ubuntu.
https://bugs.launchpad.net/bugs/1340451

Title:
  nfs client hangs when nlockmgr service at rpcbind refuses connection

Status in “nfs-utils” package in Ubuntu:
  New

Bug description:
  Steps to replicate the problem:

  1) Install NFS server at nfs-server and export /export/test
  2) Install NFS client at nfs-client and mount /export/test from nfs-server
  3) Somehow you need to block connections at nlockmgr service in the nfs-server (Connection refused). The results should be like the following:

      nfs-server ~ # rpcinfo -t 127.0.0.1 nlockmgr
      rpcinfo: RPC: Remote system error - Connection refused
      program 100021 is not available

  But, nlockmgr have to be listed in your rpcinfo -p:

      nfs-server ~ # rpcinfo -p
      program vers proto   port  service
      100000    4   tcp    111  portmapper
      100000    3   tcp    111  portmapper
      100000    2   tcp    111  portmapper
      100000    4   udp    111  portmapper
      100000    3   udp    111  portmapper
      100000    2   udp    111  portmapper
      100021    3   udp  55320  nlockmgr
      100021    3   tcp  38808  nlockmgr
      100021    4   tcp  38468  nlockmgr
      100021    1   udp    812  nlockmgr
      100021    1   tcp    814  nlockmgr
      100003    2   tcp   2049  nfs
      100003    3   tcp   2049  nfs
      100003    4   tcp   2049  nfs
      100227    2   tcp   2049
      100227    3   tcp   2049
      100003    2   udp   2049  nfs
      100003    3   udp   2049  nfs
      100003    4   udp   2049  nfs
      100227    2   udp   2049
      100227    3   udp   2049
      100005    1   udp  50765  mountd
      100005    1   tcp  52776  mountd
      100005    2   udp  42094  mountd
      100005    2   tcp  59107  mountd
      100005    3   udp  57465  mountd
      100005    3   tcp  51252  mountd
      100024    1   udp  42341  status
      100024    1   tcp  33932  status

  4) Then, you try to get a lock at any file in nfs-client. Example:
      python
      >>> import fcntl; fp = open('index.html', 'w'); fcntl.flock(fp, fcntl.LOCK_EX)

  The client will hang forever and you have to kill -9 your python
  process.

  
  nfs-client ~ # lsb_release -rd
  Description:	Ubuntu 12.04.4 LTS
  Release:	12.04

  nfs-client ~ # apt-cache policy nfs-common
  nfs-common:
    Installed: 1:1.2.5-3ubuntu3.1
    Candidate: 1:1.2.5-3ubuntu3.1
    Version table:
   *** 1:1.2.5-3ubuntu3.1 0
          500 http://br.archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
          100 /var/lib/dpkg/status
       1:1.2.5-3ubuntu3 0
          500 http://br.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/1340451/+subscriptions