ext4: Fix ext4_dx_readdir hash collision handling

This fixes a bug where readdir() would return a directory entry twice
if there was a hash collision in an hash tree indexed directory.
Signed-off-by: NEugene Dashevsky <eugene@ibrix.com>
Signed-off-by: NMike Snitzer <msnitzer@ibrix.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/ext4/dir.c

@@ -411,7 +411,7 @@ static int call_filldir(struct file * filp, void * dirent,
 				get_dtype(sb, fname->file_type));
 		if (error) {
 			filp->f_pos = curr_pos;
-			info->extra_fname = fname->next;
+			info->extra_fname = fname;
 			return error;
 		}
 		fname = fname->next;
@@ -450,11 +450,21 @@ static int ext4_dx_readdir(struct file * filp,
 	 * If there are any leftover names on the hash collision
 	 * chain, return them first.
 	 */
-	if (info->extra_fname &&
-	    call_filldir(filp, dirent, filldir, info->extra_fname))
-		goto finished;
+	if (info->extra_fname) {
+		if (call_filldir(filp, dirent, filldir, info->extra_fname))
+			goto finished;
 
-	if (!info->curr_node)
+		info->extra_fname = NULL;
+		info->curr_node = rb_next(info->curr_node);
+		if (!info->curr_node) {
+			if (info->next_hash == ~0) {
+				filp->f_pos = EXT4_HTREE_EOF;
+				goto finished;
+			}
+			info->curr_hash = info->next_hash;
+			info->curr_minor_hash = 0;
+		}
+	} else if (!info->curr_node)
 		info->curr_node = rb_first(&info->root);
 
 	while (1) {