diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
index 41e491b8e5d7..27d577dbe51a 100644
--- a/fs/lockd/clntlock.c
+++ b/fs/lockd/clntlock.c
@@ -69,6 +69,7 @@ struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
 	if (host->h_rpcclnt == NULL && nlm_bind_host(host) == NULL)
 		goto out_nobind;
 
+	host->h_nlmclnt_ops = nlm_init->nlmclnt_ops;
 	return host;
 out_nobind:
 	nlmclnt_release_host(host);
diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 112952037933..066ac313ae5c 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -150,17 +150,22 @@ static void nlmclnt_release_lockargs(struct nlm_rqst *req)
  * @host: address of a valid nlm_host context representing the NLM server
  * @cmd: fcntl-style file lock operation to perform
  * @fl: address of arguments for the lock operation
+ * @data: address of data to be sent to callback operations
  *
  */
-int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
+int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data)
 {
 	struct nlm_rqst		*call;
 	int			status;
+	const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops;
 
 	call = nlm_alloc_call(host);
 	if (call == NULL)
 		return -ENOMEM;
 
+	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call)
+		nlmclnt_ops->nlmclnt_alloc_call(data);
+
 	nlmclnt_locks_init_private(fl, host);
 	if (!fl->fl_u.nfs_fl.owner) {
 		/* lockowner allocation has failed */
@@ -169,6 +174,7 @@ int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
 	}
 	/* Set up the argument struct */
 	nlmclnt_setlockargs(call, fl);
+	call->a_callback_data = data;
 
 	if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
 		if (fl->fl_type != F_UNLCK) {
@@ -214,8 +220,12 @@ struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
 
 void nlmclnt_release_call(struct nlm_rqst *call)
 {
+	const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops;
+
 	if (!atomic_dec_and_test(&call->a_count))
 		return;
+	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call)
+		nlmclnt_ops->nlmclnt_release_call(call->a_callback_data);
 	nlmclnt_release_host(call->a_host);
 	nlmclnt_release_lockargs(call);
 	kfree(call);
@@ -687,6 +697,19 @@ out:
 	return status;
 }
 
+static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data)
+{
+	struct nlm_rqst	*req = data;
+	const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops;
+	bool defer_call = false;
+
+	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare)
+		defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data);
+
+	if (!defer_call)
+		rpc_call_start(task);
+}
+
 static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
 {
 	struct nlm_rqst	*req = data;
@@ -720,6 +743,7 @@ die:
 }
 
 static const struct rpc_call_ops nlmclnt_unlock_ops = {
+	.rpc_call_prepare = nlmclnt_unlock_prepare,
 	.rpc_call_done = nlmclnt_unlock_callback,
 	.rpc_release = nlmclnt_rpc_release,
 };
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 3e7b2e6a7cfb..e0302101e18a 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -546,6 +546,7 @@ static int nfs_start_lockd(struct nfs_server *server)
 		.noresvport	= server->flags & NFS_MOUNT_NORESVPORT ?
 					1 : 0,
 		.net		= clp->cl_net,
+		.nlmclnt_ops 	= clp->cl_nfs_mod->rpc_ops->nlmclnt_ops,
 	};
 
 	if (nlm_init.nfs_version > 3)
diff --git a/fs/nfs/nfs3proc.c b/fs/nfs/nfs3proc.c
index dc925b531f32..03b3c3de28f1 100644
--- a/fs/nfs/nfs3proc.c
+++ b/fs/nfs/nfs3proc.c
@@ -870,7 +870,7 @@ nfs3_proc_lock(struct file *filp, int cmd, struct file_lock *fl)
 {
 	struct inode *inode = file_inode(filp);
 
-	return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl);
+	return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl, NULL);
 }
 
 static int nfs3_have_delegation(struct inode *inode, fmode_t flags)
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index b7bca8303989..9872cf676a50 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -638,7 +638,7 @@ nfs_proc_lock(struct file *filp, int cmd, struct file_lock *fl)
 {
 	struct inode *inode = file_inode(filp);
 
-	return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl);
+	return nlmclnt_proc(NFS_SERVER(inode)->nlm_host, cmd, fl, NULL);
 }
 
 /* Helper functions for NFS lock bounds checking */
diff --git a/include/linux/lockd/bind.h b/include/linux/lockd/bind.h
index 140edab64446..05728396a1a1 100644
--- a/include/linux/lockd/bind.h
+++ b/include/linux/lockd/bind.h
@@ -18,6 +18,7 @@
 
 /* Dummy declarations */
 struct svc_rqst;
+struct rpc_task;
 
 /*
  * This is the set of functions for lockd->nfsd communication
@@ -43,6 +44,7 @@ struct nlmclnt_initdata {
 	u32			nfs_version;
 	int			noresvport;
 	struct net		*net;
+	const struct nlmclnt_operations	*nlmclnt_ops;
 };
 
 /*
@@ -52,8 +54,26 @@ struct nlmclnt_initdata {
 extern struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init);
 extern void	nlmclnt_done(struct nlm_host *host);
 
-extern int	nlmclnt_proc(struct nlm_host *host, int cmd,
-					struct file_lock *fl);
+/*
+ * NLM client operations provide a means to modify RPC processing of NLM
+ * requests.  Callbacks receive a pointer to data passed into the call to
+ * nlmclnt_proc().
+ */
+struct nlmclnt_operations {
+	/* Called on successful allocation of nlm_rqst, use for allocation or
+	 * reference counting. */
+	void (*nlmclnt_alloc_call)(void *);
+
+	/* Called in rpc_task_prepare for unlock.  A return value of true
+	 * indicates the callback has put the task to sleep on a waitqueue
+	 * and NLM should not call rpc_call_start(). */
+	bool (*nlmclnt_unlock_prepare)(struct rpc_task*, void *);
+
+	/* Called when the nlm_rqst is freed, callbacks should clean up here */
+	void (*nlmclnt_release_call)(void *);
+};
+
+extern int	nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data);
 extern int	lockd_up(struct net *net);
 extern void	lockd_down(struct net *net);
 
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index b37dee3acaba..41f7b6a04d69 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -69,6 +69,7 @@ struct nlm_host {
 	char			*h_addrbuf;	/* address eyecatcher */
 	struct net		*net;		/* host net */
 	char			nodename[UNX_MAXNODENAME + 1];
+	const struct nlmclnt_operations	*h_nlmclnt_ops;	/* Callback ops for NLM users */
 };
 
 /*
@@ -142,6 +143,7 @@ struct nlm_rqst {
 	struct nlm_block *	a_block;
 	unsigned int		a_retries;	/* Retry count */
 	u8			a_owner[NLMCLNT_OHSIZE];
+	void *	a_callback_data; /* sent to nlmclnt_operations callbacks */
 };
 
 /*
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index 51e27f9746ee..677c6b91dfcd 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1551,6 +1551,7 @@ struct nfs_rpc_ops {
 	const struct inode_operations *dir_inode_ops;
 	const struct inode_operations *file_inode_ops;
 	const struct file_operations *file_ops;
+	const struct nlmclnt_operations *nlmclnt_ops;
 
 	int	(*getroot) (struct nfs_server *, struct nfs_fh *,
 			    struct nfs_fsinfo *);