[PATCH] knfsd: lockd: optionally use hostnames for identifying peers

This patch adds the nsm_use_hostnames sysctl and module param.  If set, lockd
will use the client's name (as given in the NLM arguments) to find the NSM
handle.  This makes recovery work when the NFS peer is multi-homed, and the
reboot notification arrives from a different IP than the original lock calls.

Signed-off-by: Olaf Kirch <okir@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>