[DLM] fix send_args() lvb copying

The send_args() function is used to copy parameters into a message for a
number different message types.  Only some of those types are set up
beforehand (in create_message) to include space for sending lvb data.
send_args was wrongly copying the lvb for all message types as long as the
lock had an lvb.  This means that the lvb data was being written past the
end of the message into unknown space.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/dlm/lock.c

@@ -2144,12 +2144,24 @@ static void send_args(struct dlm_rsb *r, struct dlm_lkb *lkb,
 	if (lkb->lkb_astaddr)
 		ms->m_asts |= AST_COMP;
 
-	if (ms->m_type == DLM_MSG_REQUEST || ms->m_type == DLM_MSG_LOOKUP)
-		memcpy(ms->m_extra, r->res_name, r->res_length);
+	/* compare with switch in create_message; send_remove() doesn't
+	   use send_args() */
 
-	else if (lkb->lkb_lvbptr)
+	switch (ms->m_type) {
+	case DLM_MSG_REQUEST:
+	case DLM_MSG_LOOKUP:
+		memcpy(ms->m_extra, r->res_name, r->res_length);
+		break;
+	case DLM_MSG_CONVERT:
+	case DLM_MSG_UNLOCK:
+	case DLM_MSG_REQUEST_REPLY:
+	case DLM_MSG_CONVERT_REPLY:
+	case DLM_MSG_GRANT:
+		if (!lkb->lkb_lvbptr)
+			break;
 		memcpy(ms->m_extra, lkb->lkb_lvbptr, r->res_ls->ls_lvblen);
-
+		break;
+	}
 }
 
 static int send_common(struct dlm_rsb *r, struct dlm_lkb *lkb, int mstype)