[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>

1 files changed, 10 insertions, 0 deletions

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 3cc369e5693f..a3b7602cd383 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -61,6 +61,7 @@ static DECLARE_WAIT_QUEUE_HEAD(lockd_exit);
 static unsigned long            nlm_grace_period;
 static unsigned long            nlm_timeout = LOCKD_DFLT_TIMEO;
 static int                      nlm_udpport, nlm_tcpport;
+int                             nsm_use_hostnames = 0;
 
 /*
  * Constants needed for the sysctl interface.
@@ -395,6 +396,14 @@ static ctl_table nlm_sysctls[] = {
                 .extra1         = (int *) &nlm_port_min,
                 .extra2         = (int *) &nlm_port_max,
         },
+        {
+                .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "nsm_use_hostnames",
+                .data           = &nsm_use_hostnames,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
         { .ctl_name = 0 }
 };
 
@@ -483,6 +492,7 @@ module_param_call(nlm_udpport, param_set_port, param_get_int,
                   &nlm_udpport, 0644);
 module_param_call(nlm_tcpport, param_set_port, param_get_int,
                   &nlm_tcpport, 0644);
+module_param(nsm_use_hostnames, bool, 0644);
 
 /*
  * Initialising and terminating the module.