[Cluster-devel] [PATCH 0/4 Revised] NLM - lock failover

[Wendy Cheng <wcheng@redhat.com>]

Revised patches based on 2.6.21-rc4 kernel and nfs-utils-1.1.0-rc1 that 
address issues discussed in:
https://www.redhat.com/archives/cluster-devel/2006-September/msg00034.html

Quick How-to:
1) Failover server exports filesystem with "fsid" option as:
    /etc/exports entry> /mnt/shared/exports *(fsid=1234,sync,rw)
2) Failover server dispatch rpc.statd with "-H" option.
3) Failover server drops locks based on fsid by:
    shell> echo 1234 > /proc/fs/nfsd/nlm_unlock
4) Takeover server enters per fsid grace period by:
    shell> echo 1234 > /proc/fs/nfsd/nlm_set_igrace
5) Takeover server notifies clients for lock reclaim by:
    shell> /usr/sbin/sm-notify -f -v floating_ip_address -P an_sm_directory

Patch Summary:
4-1: implement /proc/fs/nfsd/nlm_unlock
4-2: implement /proc/fs/nfsd/nlm_set_igrace
4-3: correctly record and pass incoming server ip interface into rpc.statd.
4-4: nfs-utils statd changes
4-1 includes an existing lockd bug fix as discussed in:
http://sourceforge.net/mailarchive/forum.php?thread_name=4603506D.5040807%40redhat.com&forum_name=nfs
(subject: [NFS] Question about f_count in struct nlm_file)
4-4 includes an existing nfs-utils statd bug fix as discussed in:
http://sourceforge.net/mailarchive/message.php?msg_name=46142B4F.1030507%40redhat.com
(subject: Re: [NFS] lockd and statd)

Misc:
o No IPV6 support due to testing efforts
o NFS V3 only - will compare notes with CITI folks (NFS V4 issues)
o Still need some error-inject tests.

-- Wendy