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Bug#582107: mounts default to version 4, don't fall back automatically



Package: nfs-common
Version: 1:1.2.2-1
Severity: normal


I don't mean to intrude in this bug report, but I have been experiencing
a similar issue for several months.  I did not report a bug for two
reasons:

1)  I believed there must have been some recent change upstream (late
2009 or early 2010) which caused the mounting behavior of NFS to change.

2)  I mostly use custom-compiled kernels, and only keep a Debian kernel
installed in case I do something completely stupid with my own kernels
and need a safety net.

In short, I didn't think there was a bug:  I guessed the change in NFS
mounting behavior was related to a transition to NFSv4, which I have not
been using in my kernels.  Upon closer inspection, I think there may be
a bug after all.


I don't mount NFS shares using /etc/fstab, but instead have a one-liner
script which I run when the "fileserver" machine is actually turned on
and I want to use it:

mount -t nfs -o rw,async,hard,intr fileserver:/path/to/files /local/mount/point

My homemade kernel fails with this error message

    mount.nfs: an incorrect mount option was specified

while running the same command with the Debian kernel succeeds.  (My
homemade kernel also succeeds if I add "nfsvers=3" to the mount
options.)  When my script first failed a few months ago, I assumed that
upstream had changed to prefer NFSv4 and that NFSv3 had to be manually
selected.

When I began compiling my own kernels a few years ago, NFSv4 was
experimental and I chose not to enable it; the '.config' settings I use
(both on my desktop machine and on the "fileserver" machine) for NFS
look like this:

    CONFIG_NFS_FS=y
    CONFIG_NFS_V3=y
    # CONFIG_NFS_V3_ACL is not set
    # CONFIG_NFS_V4 is not set
    CONFIG_NFSD=y
    CONFIG_NFSD_V3=y
    # CONFIG_NFSD_V3_ACL is not set
    # CONFIG_NFSD_V4 is not set
    CONFIG_NFS_COMMON=y

In other words, the NFS server on "fileserver" only supports NFSv3.

Looking more carefully at the man pages for 'mount' and 'nfs', I now see
that nfs-client _should_ be able to automatically negotiate a
connection; NFSv4 has nothing to do with the problem, since my one-liner
script is using a mount type of "nfs" (and not "nfs4").

I wonder whether the OP is using a Debian kernel or a custom-compiled
one?  For me, Debian kernels mount NFSv3 just fine; only my custom build
does not work.


(I just wanted to add this information to the bug report, in case it is
helpful in some way.  I will soon be adding NFSv4 support to my home
network -- long overdue -- and the "nfsvers=3" workaround wasn't very
difficult to use anyway.)


Dave W.


-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (350, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.34+drt100429.0818fe9.desktop.kms (SMP w/4 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages nfs-common depends on:
ii  adduser                  3.112           add and remove users and groups
ii  initscripts              2.88dsf-5       scripts for initializing and shutt
ii  libc6                    2.10.2-8        Embedded GNU C Library: Shared lib
ii  libcap2                  1:2.17-2        support for getting/setting POSIX.
ii  libcomerr2               1.41.12-1       common error description library
ii  libevent-1.4-2           1.4.13-stable-1 An asynchronous event notification
ii  libgssapi-krb5-2         1.8.1+dfsg-2    MIT Kerberos runtime libraries - k
ii  libgssglue1              0.1-4           mechanism-switch gssapi library
ii  libk5crypto3             1.8.1+dfsg-2    MIT Kerberos runtime libraries - C
ii  libkrb5-3                1.8.1+dfsg-2    MIT Kerberos runtime libraries
ii  libnfsidmap2             0.23-2          An nfs idmapping library
ii  librpcsecgss3            0.19-2          allows secure rpc communication us
ii  libwrap0                 7.6.q-18        Wietse Venema's TCP wrappers libra
ii  lsb-base                 3.2-23.1        Linux Standard Base 3.2 init scrip
ii  netbase                  4.41            Basic TCP/IP networking system
ii  portmap                  6.0.0-2         RPC port mapper
ii  ucf                      3.0025          Update Configuration File: preserv

nfs-common recommends no packages.

nfs-common suggests no packages.

-- no debconf information



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