Bug#638157: nfs-common: NFSv4 hung up other progams when the server disconnected.

[Hughe Chung <maildeliveragent@gmail.com>]

Package: nfs-common
Version: 1:1.2.2-4
Severity: normal


When the network file server is shut down or disconnected, nfs daemon makes 
other programs in client hung up when they access directories. Unless manually 
unmount the directory by 'sudo umount -fl /media/nfs.'

Programs that shows hung up includes: df, ls, vlc, and etc. Opening files
freezes the program. autofs5 doesn't handle the server disconnection
gracefully. 

Secondly it prevents pm-suspend putting the system in sleep mode. 

Nov 27 17:24:46 theblue kernel: [66832.357238]  [<ffffffffa051cc76>]
nfs_revalidate_inode+0x36/0x60 [nfs]
Nov 27 17:24:46 theblue kernel: [66832.357248]  [<ffffffffa051d34f>]
nfs_getattr+0x5f/0x110 [nfs]
Nov 27 17:24:46 theblue kernel: [66832.357251]  [<ffffffff811426fe>]
vfs_getattr+0x4e/0x80
Nov 27 17:24:46 theblue kernel: [66832.357254]  [<ffffffff811427a0>]
vfs_fstatat+0x70/0x90
Nov 27 17:24:46 theblue kernel: [66832.357258]  [<ffffffff810f141f>] ?
free_pages+0x4f/0x60
Nov 27 17:24:46 theblue kernel: [66832.357260]  [<ffffffff8114289b>]
vfs_stat+0x1b/0x20
Nov 27 17:24:46 theblue kernel: [66832.357263]  [<ffffffff811428c4>]
sys_newstat+0x24/0x50
Nov 27 17:24:46 theblue kernel: [66832.357267]  [<ffffffff815309ab>]
system_call_fastpath+0x16/0x1b

I added extra options "nolock,_netdev,proto=tcp,hart" to fix pm-suspend and hung-up problem in /etc/fstab followed by:
 # mini 192.168.1.101
 mini:/archive /media/nfs nfs
 nolock,_netdev,proto=tcp,hard,intr,rsize=8192,wsize
 =8192      0   0

Also created a NFS mount daemon script that checks the server is alive.
/usr/local/bin/nfs-mount
#!/bin/bash
# 11/28/2011
# Trouble shooting of NFS hung by pm-suspend, df, other programs when NFS is dow
n.


# The hostname or IP-address of the fileserver:
# IP is 192.168.1.101
NFS="mini"

# Check every X seconds (60 is a good default):
INTERVAL=60

# The shares that need to be mounted:
SHARED_DIR="/archive"
MOUNT_DIR="/media/nfs"

while true; do
    ping -c 1 "$NFS" &>/dev/null
    if [ $? -eq 0 ]; then
        # Fileserver is up.
        logger "File server: $NFS is up."
        # mount -t nfs ${NFS}:${SHARED_DIR} ${MOUNT_DIR}
        mount ${NFS}:${SHARED_DIR}
 else
        # Fileserver is down.
        logger "Fileserver: $NFS is down."
        umount -fl ${MOUNT_DIR}
        if [ $? -eq 0 ]; then
                logger "$MOUNT_DIR" unmouted.
        else
                logger "$MOUNT_DIR" unmouting failed.
        fi
    fi
    sleep $INTERVAL
done
## end of nfs-mount 


-- System Information:
Debian Release: 6.0.3
  APT prefers stable
  APT policy: (1001, 'stable'), (650, 'testing'), (500, 'stable-updates')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.39amd64hp (SMP w/2 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+nmu2           add and remove users and groups
ii  initscripts         2.88dsf-13.1         scripts for initializing and shutt
ii  libc6               2.11.2-10            Embedded GNU C Library: Shared lib
ii  libcap2             1:2.19-3             support for getting/setting POSIX.
ii  libcomerr2          1.41.12-4stable1     common error description library
ii  libevent-1.4-2      1.4.13-stable-1      An asynchronous event notification
ii  libgssapi-krb5-2    1.8.3+dfsg-4squeeze2 MIT Kerberos runtime libraries - k
ii  libgssglue1         0.1-4                mechanism-switch gssapi library
ii  libk5crypto3        1.8.3+dfsg-4squeeze2 MIT Kerberos runtime libraries - C
ii  libkrb5-3           1.8.3+dfsg-4squeeze2 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-19             Wietse Venema's TCP wrappers libra
ii  lsb-base            3.2-23.2squeeze1     Linux Standard Base 3.2 init scrip
ii  netbase             4.45                 Basic TCP/IP networking system
ii  portmap             6.0.0-2              RPC port mapper
ii  ucf                 3.0025+nmu1          Update Configuration File: preserv

nfs-common recommends no packages.

nfs-common suggests no packages.

-- no debconf information