inotify: fix length reporting and size checking

0db501bd0610ee0c0 introduced a regresion in that it now sends a nul
terminator but the length accounting when checking for space or
reporting to userspace did not take this into account.  This corrects
all of the rounding logic.

Signed-off-by: Eric Paris <eparis@redhat.com>

fs/notify/inotify/inotify_user.c

@@ -154,7 +154,8 @@ static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
 
 	event = fsnotify_peek_notify_event(group);
 
-	event_size += roundup(event->name_len, event_size);
+	if (event->name_len)
+		event_size += roundup(event->name_len + 1, event_size);
 
 	if (event_size > count)
 		return ERR_PTR(-EINVAL);
@@ -327,8 +328,9 @@ static long inotify_ioctl(struct file *file, unsigned int cmd,
 		list_for_each_entry(holder, &group->notification_list, event_list) {
 			event = holder->event;
 			send_len += sizeof(struct inotify_event);
-			send_len += roundup(event->name_len,
-					     sizeof(struct inotify_event));
+			if (event->name_len)
+				send_len += roundup(event->name_len + 1,
+						sizeof(struct inotify_event));
 		}
 		mutex_unlock(&group->notification_mutex);
 		ret = put_user(send_len, (int __user *) p);