diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index dbbefbc..1adcf93 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -18,6 +18,8 @@
 #include <linux/lockd/lockd.h>
 #include <linux/lockd/share.h>
 #include <linux/lockd/sm_inter.h>
+#include <linux/module.h>
+#include <linux/mount.h>
 
 #define NLMDBG_FACILITY		NLMDBG_SVCSUBS
 
@@ -230,7 +232,7 @@
  * Loop over all files in the file table.
  */
 static int
-nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
+nlm_traverse_files(void *data, nlm_host_match_fn_t match)
 {
 	struct hlist_node *pos, *next;
 	struct nlm_file	*file;
@@ -244,7 +246,7 @@
 
 			/* Traverse locks, blocks and shares of this file
 			 * and update file->f_locks count */
-			if (nlm_inspect_file(host, file, match))
+			if (nlm_inspect_file(data, file, match))
 				ret = 1;
 
 			mutex_lock(&nlm_file_mutex);
@@ -303,21 +305,27 @@
  *	Used by nlmsvc_invalidate_all
  */
 static int
-nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
+nlmsvc_mark_host(void *data, struct nlm_host *dummy)
 {
+	struct nlm_host *host = data;
+
 	host->h_inuse = 1;
 	return 0;
 }
 
 static int
-nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
+nlmsvc_same_host(void *data, struct nlm_host *other)
 {
+	struct nlm_host *host = data;
+
 	return host == other;
 }
 
 static int
-nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
+nlmsvc_is_client(void *data, struct nlm_host *dummy)
 {
+	struct nlm_host *host = data;
+
 	if (host->h_server) {
 		/* we are destroying locks even though the client
 		 * hasn't asked us too, so don't unmonitor the
@@ -370,3 +378,21 @@
 	 */
 	nlm_traverse_files(NULL, nlmsvc_is_client);
 }
+
+static int
+nlmsvc_match_ip(void *datap, struct nlm_host *host)
+{
+	__be32 *server_addr = datap;
+
+	return host->h_saddr.sin_addr.s_addr == *server_addr;
+}
+
+int
+nlmsvc_unlock_all_by_ip(__be32 server_addr)
+{
+	int ret;
+	ret = nlm_traverse_files(&server_addr, nlmsvc_match_ip);
+	return ret ? -EIO : 0;
+
+}
+EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip);
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 613bcb8..7706f6c 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -22,6 +22,7 @@
 #include <linux/seq_file.h>
 #include <linux/pagemap.h>
 #include <linux/init.h>
+#include <linux/inet.h>
 #include <linux/string.h>
 #include <linux/smp_lock.h>
 #include <linux/ctype.h>
@@ -35,6 +36,7 @@
 #include <linux/nfsd/cache.h>
 #include <linux/nfsd/xdr.h>
 #include <linux/nfsd/syscall.h>
+#include <linux/lockd/lockd.h>
 
 #include <asm/uaccess.h>
 #include <net/ipv6.h>
@@ -53,6 +55,7 @@
 	NFSD_Getfs,
 	NFSD_List,
 	NFSD_Fh,
+	NFSD_FO_UnlockIP,
 	NFSD_Threads,
 	NFSD_Pool_Threads,
 	NFSD_Versions,
@@ -89,6 +92,8 @@
 static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
 #endif
 
+static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
+
 static ssize_t (*write_op[])(struct file *, char *, size_t) = {
 	[NFSD_Svc] = write_svc,
 	[NFSD_Add] = write_add,
@@ -98,6 +103,7 @@
 	[NFSD_Getfd] = write_getfd,
 	[NFSD_Getfs] = write_getfs,
 	[NFSD_Fh] = write_filehandle,
+	[NFSD_FO_UnlockIP] = failover_unlock_ip,
 	[NFSD_Threads] = write_threads,
 	[NFSD_Pool_Threads] = write_pool_threads,
 	[NFSD_Versions] = write_versions,
@@ -298,6 +304,31 @@
 	return err;
 }
 
+static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
+{
+	__be32 server_ip;
+	char *fo_path, c;
+	int b1, b2, b3, b4;
+
+	/* sanity check */
+	if (size == 0)
+		return -EINVAL;
+
+	if (buf[size-1] != '\n')
+		return -EINVAL;
+
+	fo_path = buf;
+	if (qword_get(&buf, fo_path, size) < 0)
+		return -EINVAL;
+
+	/* get ipv4 address */
+	if (sscanf(fo_path, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
+		return -EINVAL;
+	server_ip = htonl((((((b1<<8)|b2)<<8)|b3)<<8)|b4);
+
+	return nlmsvc_unlock_all_by_ip(server_ip);
+}
+
 static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
 {
 	/* request is:
@@ -700,6 +731,8 @@
 		[NFSD_Getfd] = {".getfd", &transaction_ops, S_IWUSR|S_IRUSR},
 		[NFSD_Getfs] = {".getfs", &transaction_ops, S_IWUSR|S_IRUSR},
 		[NFSD_List] = {"exports", &exports_operations, S_IRUGO},
+		[NFSD_FO_UnlockIP] = {"unlock_ip",
+					&transaction_ops, S_IWUSR|S_IRUSR},
 		[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
 		[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
 		[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index 94649a8..bcb93fc 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -194,7 +194,7 @@
  * This is used in garbage collection and resource reclaim
  * A return value != 0 means destroy the lock/block/share
  */
-typedef int	  (*nlm_host_match_fn_t)(struct nlm_host *cur, struct nlm_host *ref);
+typedef int	  (*nlm_host_match_fn_t)(void *cur, struct nlm_host *ref);
 
 /*
  * Server-side lock handling
@@ -220,6 +220,11 @@
 void		  nlmsvc_free_host_resources(struct nlm_host *);
 void		  nlmsvc_invalidate_all(void);
 
+/*
+ * Cluster failover support
+ */
+int           nlmsvc_unlock_all_by_ip(__be32 server_addr);
+
 static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
 {
 	return file->f_file->f_path.dentry->d_inode;