+++ This bug was initially created as a clone of Bug #512377 +++

Description of problem:
Last night's Fedora 11 nfs-utils upgrade broke NFSv4.

Problem machine:  Fedora 11/x86-64, NFSv4 server (kernel version below)

Attached was a lone NFSv4 client:  Fedora 10/x86-64, kernel 2.6.30 vanilla.

After yum upgraded nfs-utils, syscalls on the NFSv4 client started failing with "Protocol not supported".

On the NFSv4 server, where the nfs-utils package upgrade had just taken place, the log was filling with a steady stream of messages:
Jul 17 05:58:14 pretzel kernel: svc: 10.10.20.30, port=763: unknown version (4 for prog 100003, nfsd)
Jul 17 05:58:15 pretzel kernel: svc: 10.10.20.30, port=763: unknown version (4 for prog 100003, nfsd)
Jul 17 05:58:15 pretzel kernel: svc: 10.10.20.30, port=763: unknown version (4 for prog 100003, nfsd)
Jul 17 05:58:17 pretzel kernel: svc: 10.10.20.30, port=763: unknown version (4 for prog 100003, nfsd)
Jul 17 05:58:17 pretzel kernel: svc: 10.10.20.30, port=763: unknown version (4 for prog 100003, nfsd)

10.10.20.30 is the NFSv4 client mentioned above.


Version-Release number of selected component (if applicable):
nfs-utils-1.2.0-3.fc11.x86_64
kernel-2.6.29.5-191.fc11.x86_64


How reproducible:
unknown

Steps to Reproduce:
1. set up nfsv4 server, nfsv4 client.
2. mount server, on client
3. upgrade nfs-utils on server
  
Actual results:
see above

Expected results:
working client

Additional info:
NFSv4 client /etc/fstab line:
pretzel:/		/g			nfs4	defaults,noatime 0 0

(pretzel == the problematic NFSv4 server)

--- Additional comment from jussi.eloranta on 2009-07-17 12:30:45 EDT ---

I ran into the same problem, on 32bit system. This caused a major headache this morning :-(

--- Additional comment from bfields on 2009-07-17 12:58:52 EDT ---

/proc/fs/nfsd/versions was extended to allow turning on/off minor versions by echoing "+4.1" or "-4.1" to /proc/fs/nsfd/versions.

Unfortunately, pre-2.6.30 kernels just stop parsing at first non-digit, so "-4.1" is interpreted as "-4".  If new nfs-utils (on old kernel) writes "+2", "+3", "+4", then "-4.1", result therefore is to turn off 4.1....

Turning off the minorversion first should work.  Or just not bothering, since the kernel leaves it off by default.

But the interface now seems more delicate than intended.  Better might be to violate the rule against changing upstream user<->kernel api's (nobody user wants 4.1 yet anyway), and add a new /proc/fs/nsfd/v4_minor_versions file instead....

--- Additional comment from amessina on 2009-07-17 19:27:46 EDT ---

What is the proposed workaround for F11 until the 2.6.30 kernel is released, besides reverting to NFSv3?  This has killed my entire network with NFSv4 mounted /home directories.

I'm confused as to why this nfs-utils would be pushed to stable without the necessary kernel to support the change for NFSv4.

--- Additional comment from jbastian on 2009-07-22 11:23:30 EDT ---

A colleague of mine, Sachin Prabhu, suggested removing the '-N 4.1' argument from the rpc.nfsd line in /etc/rc.d/init.d/nfs; see below.

This fixed it for me.  Of course, NOT disabling 4.1 may introduce new problems...


--- /etc/rc.d/init.d/nfs.ORIG   2009-06-11 13:13:23.000000000 -0500
+++ /etc/rc.d/init.d/nfs        2009-07-22 10:09:44.083889410 -0500
@@ -94,7 +94,7 @@

        echo -n $"Starting NFS daemon: "
        # For now, turn off the nfs41 support
-       daemon rpc.nfsd -N 4.1 $RPCNFSDARGS $RPCNFSDCOUNT
+       daemon rpc.nfsd $RPCNFSDARGS $RPCNFSDCOUNT
        RETVAL=$?
        echo
        [ $RETVAL -ne 0 ] && exit $RETVAL

--- Additional comment from jgarzik on 2009-07-23 17:44:43 EDT ---

This affects rawhide as well as Fedora 11.