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

[Wendy Cheng]

The revised patches address the issues discussed in previous review:

https://www.redhat.com/archives/cluster-devel/2006-August/msg00194.html.

The changes made are mostly for grace period fsid list that was 
previously implemented as a single linked list. It is now a double 
linked list with max entries count set to 128.

Quick How-to:
1) Failover server exports filesystem with "fsid" option as:
    /etc/exports entry> /mnt/ext3/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> rpc.statd -n floating_ip_address -N -P recovery_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: (for reference purpose) user mode rpc.statd patch

-- Wendy