inotify: do not send a block of zeros when no pathname is available

When an event has no pathname, there's no need to pad it with a null byte and
therefore generate an inotify_event sized block of zeros. This fixes a
regression introduced by commit 0db501bd0610ee0c0aca84d927f90bcccd09e2bd where
my system wouldn't finish booting because some process was being confused by
this.

Signed-off-by: Brian Rogers <brian@xyzw.org>
Signed-off-by: Eric Paris <eparis@redhat.com>

fs/notify/inotify/inotify_user.c

@@ -180,7 +180,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 	struct fsnotify_event_private_data *fsn_priv;
 	struct inotify_event_private_data *priv;
 	size_t event_size = sizeof(struct inotify_event);
-	size_t name_len;
+	size_t name_len = 0;
 
 	/* we get the inotify watch descriptor from the event private data */
 	spin_lock(&event->lock);
@@ -196,10 +196,12 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 		inotify_free_event_priv(fsn_priv);
 	}
 
-	/* round up event->name_len so it is a multiple of event_size
+	/*
+	 * round up event->name_len so it is a multiple of event_size
 	 * plus an extra byte for the terminating '\0'.
 	 */
-	name_len = roundup(event->name_len + 1, event_size);
+	if (event->name_len)
+		name_len = roundup(event->name_len + 1, event_size);
 	inotify_event.len = name_len;
 
 	inotify_event.mask = inotify_mask_to_arg(event->mask);