diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a204d7e109d4..ca0db4974e5b 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -99,6 +99,7 @@ static struct kmem_cache *odstate_slab;
 static void free_session(struct nfsd4_session *);
 
 static const struct nfsd4_callback_ops nfsd4_cb_recall_ops;
+static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops;
 
 static bool is_session_dead(struct nfsd4_session *ses)
 {
@@ -210,6 +211,84 @@ static void nfsd4_put_session(struct nfsd4_session *ses)
 	spin_unlock(&nn->client_lock);
 }
 
+static struct nfsd4_blocked_lock *
+find_blocked_lock(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
+			struct nfsd_net *nn)
+{
+	struct nfsd4_blocked_lock *cur, *found = NULL;
+
+	spin_lock(&nn->client_lock);
+	list_for_each_entry(cur, &lo->lo_blocked, nbl_list) {
+		if (fh_match(fh, &cur->nbl_fh)) {
+			list_del_init(&cur->nbl_list);
+			found = cur;
+			break;
+		}
+	}
+	spin_unlock(&nn->client_lock);
+	if (found)
+		posix_unblock_lock(&found->nbl_lock);
+	return found;
+}
+
+static struct nfsd4_blocked_lock *
+find_or_allocate_block(struct nfs4_lockowner *lo, struct knfsd_fh *fh,
+			struct nfsd_net *nn)
+{
+	struct nfsd4_blocked_lock *nbl;
+
+	nbl = find_blocked_lock(lo, fh, nn);
+	if (!nbl) {
+		nbl= kmalloc(sizeof(*nbl), GFP_KERNEL);
+		if (nbl) {
+			fh_copy_shallow(&nbl->nbl_fh, fh);
+			locks_init_lock(&nbl->nbl_lock);
+			nfsd4_init_cb(&nbl->nbl_cb, lo->lo_owner.so_client,
+					&nfsd4_cb_notify_lock_ops,
+					NFSPROC4_CLNT_CB_NOTIFY_LOCK);
+		}
+	}
+	return nbl;
+}
+
+static void
+free_blocked_lock(struct nfsd4_blocked_lock *nbl)
+{
+	locks_release_private(&nbl->nbl_lock);
+	kfree(nbl);
+}
+
+static int
+nfsd4_cb_notify_lock_done(struct nfsd4_callback *cb, struct rpc_task *task)
+{
+	/*
+	 * Since this is just an optimization, we don't try very hard if it
+	 * turns out not to succeed. We'll requeue it on NFS4ERR_DELAY, and
+	 * just quit trying on anything else.
+	 */
+	switch (task->tk_status) {
+	case -NFS4ERR_DELAY:
+		rpc_delay(task, 1 * HZ);
+		return 0;
+	default:
+		return 1;
+	}
+}
+
+static void
+nfsd4_cb_notify_lock_release(struct nfsd4_callback *cb)
+{
+	struct nfsd4_blocked_lock	*nbl = container_of(cb,
+						struct nfsd4_blocked_lock, nbl_cb);
+
+	free_blocked_lock(nbl);
+}
+
+static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops = {
+	.done		= nfsd4_cb_notify_lock_done,
+	.release	= nfsd4_cb_notify_lock_release,
+};
+
 static inline struct nfs4_stateowner *
 nfs4_get_stateowner(struct nfs4_stateowner *sop)
 {
@@ -5309,7 +5388,29 @@ nfsd4_fl_put_owner(fl_owner_t owner)
 		nfs4_put_stateowner(&lo->lo_owner);
 }
 
+static void
+nfsd4_lm_notify(struct file_lock *fl)
+{
+	struct nfs4_lockowner		*lo = (struct nfs4_lockowner *)fl->fl_owner;
+	struct net			*net = lo->lo_owner.so_client->net;
+	struct nfsd_net			*nn = net_generic(net, nfsd_net_id);
+	struct nfsd4_blocked_lock	*nbl = container_of(fl,
+						struct nfsd4_blocked_lock, nbl_lock);
+	bool queue = false;
+
+	spin_lock(&nn->client_lock);
+	if (!list_empty(&nbl->nbl_list)) {
+		list_del_init(&nbl->nbl_list);
+		queue = true;
+	}
+	spin_unlock(&nn->client_lock);
+
+	if (queue)
+		nfsd4_run_cb(&nbl->nbl_cb);
+}
+
 static const struct lock_manager_operations nfsd_posix_mng_ops  = {
+	.lm_notify = nfsd4_lm_notify,
 	.lm_get_owner = nfsd4_fl_get_owner,
 	.lm_put_owner = nfsd4_fl_put_owner,
 };
@@ -5407,6 +5508,7 @@ alloc_init_lock_stateowner(unsigned int strhashval, struct nfs4_client *clp,
 	lo = alloc_stateowner(lockowner_slab, &lock->lk_new_owner, clp);
 	if (!lo)
 		return NULL;
+	INIT_LIST_HEAD(&lo->lo_blocked);
 	INIT_LIST_HEAD(&lo->lo_owner.so_stateids);
 	lo->lo_owner.so_is_open_owner = 0;
 	lo->lo_owner.so_seqid = lock->lk_new_lock_seqid;
@@ -5588,12 +5690,15 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	struct nfs4_ol_stateid *open_stp = NULL;
 	struct nfs4_file *fp;
 	struct file *filp = NULL;
+	struct nfsd4_blocked_lock *nbl = NULL;
 	struct file_lock *file_lock = NULL;
 	struct file_lock *conflock = NULL;
 	__be32 status = 0;
 	int lkflg;
 	int err;
 	bool new = false;
+	unsigned char fl_type;
+	unsigned int fl_flags = FL_POSIX;
 	struct net *net = SVC_NET(rqstp);
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
@@ -5658,46 +5763,55 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (!locks_in_grace(net) && lock->lk_reclaim)
 		goto out;
 
-	file_lock = locks_alloc_lock();
-	if (!file_lock) {
-		dprintk("NFSD: %s: unable to allocate lock!\n", __func__);
-		status = nfserr_jukebox;
-		goto out;
-	}
-
 	fp = lock_stp->st_stid.sc_file;
 	switch (lock->lk_type) {
-		case NFS4_READ_LT:
 		case NFS4_READW_LT:
+			if (nfsd4_has_session(cstate))
+				fl_flags |= FL_SLEEP;
+			/* Fallthrough */
+		case NFS4_READ_LT:
 			spin_lock(&fp->fi_lock);
 			filp = find_readable_file_locked(fp);
 			if (filp)
 				get_lock_access(lock_stp, NFS4_SHARE_ACCESS_READ);
 			spin_unlock(&fp->fi_lock);
-			file_lock->fl_type = F_RDLCK;
+			fl_type = F_RDLCK;
 			break;
-		case NFS4_WRITE_LT:
 		case NFS4_WRITEW_LT:
+			if (nfsd4_has_session(cstate))
+				fl_flags |= FL_SLEEP;
+			/* Fallthrough */
+		case NFS4_WRITE_LT:
 			spin_lock(&fp->fi_lock);
 			filp = find_writeable_file_locked(fp);
 			if (filp)
 				get_lock_access(lock_stp, NFS4_SHARE_ACCESS_WRITE);
 			spin_unlock(&fp->fi_lock);
-			file_lock->fl_type = F_WRLCK;
+			fl_type = F_WRLCK;
 			break;
 		default:
 			status = nfserr_inval;
 		goto out;
 	}
+
 	if (!filp) {
 		status = nfserr_openmode;
 		goto out;
 	}
 
+	nbl = find_or_allocate_block(lock_sop, &fp->fi_fhandle, nn);
+	if (!nbl) {
+		dprintk("NFSD: %s: unable to allocate block!\n", __func__);
+		status = nfserr_jukebox;
+		goto out;
+	}
+
+	file_lock = &nbl->nbl_lock;
+	file_lock->fl_type = fl_type;
 	file_lock->fl_owner = (fl_owner_t)lockowner(nfs4_get_stateowner(&lock_sop->lo_owner));
 	file_lock->fl_pid = current->tgid;
 	file_lock->fl_file = filp;
-	file_lock->fl_flags = FL_POSIX;
+	file_lock->fl_flags = fl_flags;
 	file_lock->fl_lmops = &nfsd_posix_mng_ops;
 	file_lock->fl_start = lock->lk_offset;
 	file_lock->fl_end = last_byte_offset(lock->lk_offset, lock->lk_length);
@@ -5710,18 +5824,27 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		goto out;
 	}
 
+	if (fl_flags & FL_SLEEP) {
+		spin_lock(&nn->client_lock);
+		list_add_tail(&nbl->nbl_list, &lock_sop->lo_blocked);
+		spin_unlock(&nn->client_lock);
+	}
+
 	err = vfs_lock_file(filp, F_SETLK, file_lock, conflock);
-	switch (-err) {
+	switch (err) {
 	case 0: /* success! */
 		nfs4_inc_and_copy_stateid(&lock->lk_resp_stateid, &lock_stp->st_stid);
 		status = 0;
 		break;
-	case (EAGAIN):		/* conflock holds conflicting lock */
+	case FILE_LOCK_DEFERRED:
+		nbl = NULL;
+		/* Fallthrough */
+	case -EAGAIN:		/* conflock holds conflicting lock */
 		status = nfserr_denied;
 		dprintk("NFSD: nfsd4_lock: conflicting lock found!\n");
 		nfs4_set_lock_denied(conflock, &lock->lk_denied);
 		break;
-	case (EDEADLK):
+	case -EDEADLK:
 		status = nfserr_deadlock;
 		break;
 	default:
@@ -5730,6 +5853,15 @@ nfsd4_lock(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		break;
 	}
 out:
+	if (nbl) {
+		/* dequeue it if we queued it before */
+		if (fl_flags & FL_SLEEP) {
+			spin_lock(&nn->client_lock);
+			list_del_init(&nbl->nbl_list);
+			spin_unlock(&nn->client_lock);
+		}
+		free_blocked_lock(nbl);
+	}
 	if (filp)
 		fput(filp);
 	if (lock_stp) {
@@ -5753,8 +5885,6 @@ out:
 	if (open_stp)
 		nfs4_put_stid(&open_stp->st_stid);
 	nfsd4_bump_seqid(cstate, status);
-	if (file_lock)
-		locks_free_lock(file_lock);
 	if (conflock)
 		locks_free_lock(conflock);
 	return status;
diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
index 127cc84ca5a3..f6ffeac391f4 100644
--- a/fs/nfsd/state.h
+++ b/fs/nfsd/state.h
@@ -441,11 +441,11 @@ struct nfs4_openowner {
 /*
  * Represents a generic "lockowner". Similar to an openowner. References to it
  * are held by the lock stateids that are created on its behalf. This object is
- * a superset of the nfs4_stateowner struct (or would be if it needed any extra
- * fields).
+ * a superset of the nfs4_stateowner struct.
  */
 struct nfs4_lockowner {
-	struct nfs4_stateowner	lo_owner; /* must be first element */
+	struct nfs4_stateowner	lo_owner;	/* must be first element */
+	struct list_head	lo_blocked;	/* blocked file_locks */
 };
 
 static inline struct nfs4_openowner * openowner(struct nfs4_stateowner *so)
@@ -581,7 +581,13 @@ static inline bool nfsd4_stateid_generation_after(stateid_t *a, stateid_t *b)
 	return (s32)(a->si_generation - b->si_generation) > 0;
 }
 
+/*
+ * When a client tries to get a lock on a file, we set one of these objects
+ * on the blocking lock. When the lock becomes free, we can then issue a
+ * CB_NOTIFY_LOCK to the server.
+ */
 struct nfsd4_blocked_lock {
+	struct list_head	nbl_list;
 	struct file_lock	nbl_lock;
 	struct knfsd_fh		nbl_fh;
 	struct nfsd4_callback	nbl_cb;
