[bug] FC2/2.6.8.1 does not fallback to NFSv2

["Brandon D. Valentine" <brandon@dvalentine.com>]

[ I tried to send this yesterday without actually subscribing, but it
has yet to make it past the list moderator.  I've given up and
subscribed to yet another mailing list to get this bug report out. ]

We have just brought up several Fedora Core 2 systems running the latest
2.6.8.1 kernel revision in our NIS/NFS+autofs environment.  The FC2/2.6
clients are refusing to mount one specific filesystem on our network.
This filesystem is exported by a Debian/woody system running a 2.4.18
kernel.  The kernel on this machine only supports NFSv2 exports.

When the FC2/2.6 client attempts to automount the filesystem on the 2.4
server we observe the following in the client's syslog:

  Aug 26 18:37:08 scylla automount[5056]: >> mount to NFS server 'reef'
  failed: server is down.
  Aug 26 18:37:08 scylla automount[5056]: mount(nfs): nfs: mount failure
  reef:/export/reef/httpd/ on /sb/www
  Aug 26 18:37:08 scylla automount[5056]: failed to mount /sb/www

And the following is observed in the server's syslog:

  Aug 26 18:37:12 reef kernel: svc: unknown version (3)

At this point the client gives up with the following error:

  [root@scylla root]# ls /sb/www
  ls: /sb/www: No such file or directory

None of our other Linux systems running 2.4 kernels have any trouble
mounting that filesystem.  They all automount it using NFSv2 as
expected.  All of our 2.4 systems also correctly mount using NFSv3 from
systems that support it.

Autofs is configured on the FC2 systems to permit NFSv2 mounts as shown
by the minproto option below:

  [root@scylla root]# mount | grep automount
  automount(pid1665) on /home type autofs (rw,fd=4,pgrp=1665,minproto=2,maxproto=4)
  automount(pid1695) on /sb type autofs (rw,fd=4,pgrp=1695,minproto=2,maxproto=4)
  automount(pid1739) on /scratch type autofs (rw,fd=4,pgrp=1739,minproto=2,maxproto=4)

The 2.6.8.1 kernel is configured with the following options:

  [root@scylla root]# grep -i nfs /usr/src/linux/.config
  CONFIG_NFS_FS=y
  CONFIG_NFS_V3=y
  # CONFIG_NFS_V4 is not set
  # CONFIG_NFS_DIRECTIO is not set
  CONFIG_NFSD=y
  CONFIG_NFSD_V3=y
  # CONFIG_NFSD_V4 is not set
  CONFIG_NFSD_TCP=y

I am able to manually mount this filesystem, but only if I explicitly
add the vers=2 option to the mount command:

  [root@scylla root]# mount -t nfs reef:/export/reef/httpd/ /mnt/temp
  mount to NFS server 'reef' failed: server is down.
  [root@scylla root]# mount -t nfs -o vers=2 reef:/export/reef/httpd/ /mnt/temp
  [root@scylla root]#

Given the fact that the mount fails manually until vers=2 is specified I
am inclined to believe this is a kernel NFS bug, not an autofs or mount
bug.

I would be glad to gather any additional information that might be
necessary to determine the cause of this behavior.  Can anyone reproduce
this or have advice on how I might fix it?

Thanks,

Brandon D. Valentine
-- 
brandon@dvalentine.com                           http://www.geekpunk.net
Pseudo-Random Googlism:  sunlight is the lowest frequency and therefore
                         is the biggest wave


-------------------------------------------------------
This SF.Net email is sponsored by BEA Weblogic Workshop
FREE Java Enterprise J2EE developer tools!
Get your free copy of BEA WebLogic Workshop 8.1 today.
http://ads.osdn.com/?ad_id=5047&alloc_id=10808&op=click
_______________________________________________
NFS maillist  -  NFS@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nfs