diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index c3b9fca..c2890ef 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -3008,8 +3008,6 @@
 	lkb->lkb_bastaddr = (void *) (long) (ms->m_asts & AST_BAST);
 	lkb->lkb_astaddr = (void *) (long) (ms->m_asts & AST_COMP);
 
-	DLM_ASSERT(is_master_copy(lkb), dlm_print_lkb(lkb););
-
 	if (lkb->lkb_exflags & DLM_LKF_VALBLK) {
 		/* lkb was just created so there won't be an lvb yet */
 		lkb->lkb_lvbptr = dlm_allocate_lvb(ls);
@@ -3023,16 +3021,6 @@
 static int receive_convert_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
 				struct dlm_message *ms)
 {
-	if (lkb->lkb_nodeid != ms->m_header.h_nodeid) {
-		log_error(ls, "convert_args nodeid %d %d lkid %x %x",
-			  lkb->lkb_nodeid, ms->m_header.h_nodeid,
-			  lkb->lkb_id, lkb->lkb_remid);
-		return -EINVAL;
-	}
-
-	if (!is_master_copy(lkb))
-		return -EINVAL;
-
 	if (lkb->lkb_status != DLM_LKSTS_GRANTED)
 		return -EBUSY;
 
@@ -3048,8 +3036,6 @@
 static int receive_unlock_args(struct dlm_ls *ls, struct dlm_lkb *lkb,
 			       struct dlm_message *ms)
 {
-	if (!is_master_copy(lkb))
-		return -EINVAL;
 	if (receive_lvb(ls, lkb, ms))
 		return -ENOMEM;
 	return 0;
@@ -3065,6 +3051,50 @@
 	lkb->lkb_remid = ms->m_lkid;
 }
 
+/* This is called after the rsb is locked so that we can safely inspect
+   fields in the lkb. */
+
+static int validate_message(struct dlm_lkb *lkb, struct dlm_message *ms)
+{
+	int from = ms->m_header.h_nodeid;
+	int error = 0;
+
+	switch (ms->m_type) {
+	case DLM_MSG_CONVERT:
+	case DLM_MSG_UNLOCK:
+	case DLM_MSG_CANCEL:
+		if (!is_master_copy(lkb) || lkb->lkb_nodeid != from)
+			error = -EINVAL;
+		break;
+
+	case DLM_MSG_CONVERT_REPLY:
+	case DLM_MSG_UNLOCK_REPLY:
+	case DLM_MSG_CANCEL_REPLY:
+	case DLM_MSG_GRANT:
+	case DLM_MSG_BAST:
+		if (!is_process_copy(lkb) || lkb->lkb_nodeid != from)
+			error = -EINVAL;
+		break;
+
+	case DLM_MSG_REQUEST_REPLY:
+		if (!is_process_copy(lkb))
+			error = -EINVAL;
+		else if (lkb->lkb_nodeid != -1 && lkb->lkb_nodeid != from)
+			error = -EINVAL;
+		break;
+
+	default:
+		error = -EINVAL;
+	}
+
+	if (error)
+		log_error(lkb->lkb_resource->res_ls,
+			  "ignore invalid message %d from %d %x %x %x %d",
+			  ms->m_type, from, lkb->lkb_id, lkb->lkb_remid,
+			  lkb->lkb_flags, lkb->lkb_nodeid);
+	return error;
+}
+
 static void receive_request(struct dlm_ls *ls, struct dlm_message *ms)
 {
 	struct dlm_lkb *lkb;
@@ -3126,17 +3156,21 @@
 	hold_rsb(r);
 	lock_rsb(r);
 
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
+
 	receive_flags(lkb, ms);
 	error = receive_convert_args(ls, lkb, ms);
 	if (error)
-		goto out;
+		goto out_reply;
 	reply = !down_conversion(lkb);
 
 	error = do_convert(r, lkb);
- out:
+ out_reply:
 	if (reply)
 		send_convert_reply(r, lkb, error);
-
+ out:
 	unlock_rsb(r);
 	put_rsb(r);
 	dlm_put_lkb(lkb);
@@ -3162,15 +3196,19 @@
 	hold_rsb(r);
 	lock_rsb(r);
 
-	receive_flags(lkb, ms);
-	error = receive_unlock_args(ls, lkb, ms);
+	error = validate_message(lkb, ms);
 	if (error)
 		goto out;
 
-	error = do_unlock(r, lkb);
- out:
-	send_unlock_reply(r, lkb, error);
+	receive_flags(lkb, ms);
+	error = receive_unlock_args(ls, lkb, ms);
+	if (error)
+		goto out_reply;
 
+	error = do_unlock(r, lkb);
+ out_reply:
+	send_unlock_reply(r, lkb, error);
+ out:
 	unlock_rsb(r);
 	put_rsb(r);
 	dlm_put_lkb(lkb);
@@ -3198,9 +3236,13 @@
 	hold_rsb(r);
 	lock_rsb(r);
 
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
+
 	error = do_cancel(r, lkb);
 	send_cancel_reply(r, lkb, error);
-
+ out:
 	unlock_rsb(r);
 	put_rsb(r);
 	dlm_put_lkb(lkb);
@@ -3219,22 +3261,26 @@
 
 	error = find_lkb(ls, ms->m_remid, &lkb);
 	if (error) {
-		log_error(ls, "receive_grant no lkb");
+		log_debug(ls, "receive_grant from %d no lkb %x",
+			  ms->m_header.h_nodeid, ms->m_remid);
 		return;
 	}
-	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
 
 	r = lkb->lkb_resource;
 
 	hold_rsb(r);
 	lock_rsb(r);
 
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
+
 	receive_flags_reply(lkb, ms);
 	if (is_altmode(lkb))
 		munge_altmode(lkb, ms);
 	grant_lock_pc(r, lkb, ms);
 	queue_cast(r, lkb, 0);
-
+ out:
 	unlock_rsb(r);
 	put_rsb(r);
 	dlm_put_lkb(lkb);
@@ -3248,18 +3294,22 @@
 
 	error = find_lkb(ls, ms->m_remid, &lkb);
 	if (error) {
-		log_error(ls, "receive_bast no lkb");
+		log_debug(ls, "receive_bast from %d no lkb %x",
+			  ms->m_header.h_nodeid, ms->m_remid);
 		return;
 	}
-	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
 
 	r = lkb->lkb_resource;
 
 	hold_rsb(r);
 	lock_rsb(r);
 
-	queue_bast(r, lkb, ms->m_bastmode);
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
 
+	queue_bast(r, lkb, ms->m_bastmode);
+ out:
 	unlock_rsb(r);
 	put_rsb(r);
 	dlm_put_lkb(lkb);
@@ -3325,15 +3375,19 @@
 
 	error = find_lkb(ls, ms->m_remid, &lkb);
 	if (error) {
-		log_error(ls, "receive_request_reply no lkb");
+		log_debug(ls, "receive_request_reply from %d no lkb %x",
+			  ms->m_header.h_nodeid, ms->m_remid);
 		return;
 	}
-	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
 
 	r = lkb->lkb_resource;
 	hold_rsb(r);
 	lock_rsb(r);
 
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
+
 	mstype = lkb->lkb_wait_type;
 	error = remove_from_waiters(lkb, DLM_MSG_REQUEST_REPLY);
 	if (error)
@@ -3466,6 +3520,10 @@
 	hold_rsb(r);
 	lock_rsb(r);
 
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
+
 	/* stub reply can happen with waiters_mutex held */
 	error = remove_from_waiters_ms(lkb, ms);
 	if (error)
@@ -3484,10 +3542,10 @@
 
 	error = find_lkb(ls, ms->m_remid, &lkb);
 	if (error) {
-		log_error(ls, "receive_convert_reply no lkb");
+		log_debug(ls, "receive_convert_reply from %d no lkb %x",
+			  ms->m_header.h_nodeid, ms->m_remid);
 		return;
 	}
-	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
 
 	_receive_convert_reply(lkb, ms);
 	dlm_put_lkb(lkb);
@@ -3501,6 +3559,10 @@
 	hold_rsb(r);
 	lock_rsb(r);
 
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
+
 	/* stub reply can happen with waiters_mutex held */
 	error = remove_from_waiters_ms(lkb, ms);
 	if (error)
@@ -3532,10 +3594,10 @@
 
 	error = find_lkb(ls, ms->m_remid, &lkb);
 	if (error) {
-		log_error(ls, "receive_unlock_reply no lkb");
+		log_debug(ls, "receive_unlock_reply from %d no lkb %x",
+			  ms->m_header.h_nodeid, ms->m_remid);
 		return;
 	}
-	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
 
 	_receive_unlock_reply(lkb, ms);
 	dlm_put_lkb(lkb);
@@ -3549,6 +3611,10 @@
 	hold_rsb(r);
 	lock_rsb(r);
 
+	error = validate_message(lkb, ms);
+	if (error)
+		goto out;
+
 	/* stub reply can happen with waiters_mutex held */
 	error = remove_from_waiters_ms(lkb, ms);
 	if (error)
@@ -3580,10 +3646,10 @@
 
 	error = find_lkb(ls, ms->m_remid, &lkb);
 	if (error) {
-		log_error(ls, "receive_cancel_reply no lkb");
+		log_debug(ls, "receive_cancel_reply from %d no lkb %x",
+			  ms->m_header.h_nodeid, ms->m_remid);
 		return;
 	}
-	DLM_ASSERT(is_process_copy(lkb), dlm_print_lkb(lkb););
 
 	_receive_cancel_reply(lkb, ms);
 	dlm_put_lkb(lkb);
@@ -3816,6 +3882,7 @@
 		ls->ls_stub_ms.m_type = DLM_MSG_CONVERT_REPLY;
 		ls->ls_stub_ms.m_result = -EINPROGRESS;
 		ls->ls_stub_ms.m_flags = lkb->lkb_flags;
+		ls->ls_stub_ms.m_header.h_nodeid = lkb->lkb_nodeid;
 		_receive_convert_reply(lkb, &ls->ls_stub_ms);
 
 		/* Same special case as in receive_rcom_lock_args() */
@@ -3917,6 +3984,7 @@
 			ls->ls_stub_ms.m_type = DLM_MSG_UNLOCK_REPLY;
 			ls->ls_stub_ms.m_result = stub_unlock_result;
 			ls->ls_stub_ms.m_flags = lkb->lkb_flags;
+			ls->ls_stub_ms.m_header.h_nodeid = lkb->lkb_nodeid;
 			_receive_unlock_reply(lkb, &ls->ls_stub_ms);
 			dlm_put_lkb(lkb);
 			break;
@@ -3926,6 +3994,7 @@
 			ls->ls_stub_ms.m_type = DLM_MSG_CANCEL_REPLY;
 			ls->ls_stub_ms.m_result = stub_cancel_result;
 			ls->ls_stub_ms.m_flags = lkb->lkb_flags;
+			ls->ls_stub_ms.m_header.h_nodeid = lkb->lkb_nodeid;
 			_receive_cancel_reply(lkb, &ls->ls_stub_ms);
 			dlm_put_lkb(lkb);
 			break;