diff --git a/e2fsck/dirinfo.c b/e2fsck/dirinfo.c
index c5183261..fab10d89 100644
--- a/e2fsck/dirinfo.c
+++ b/e2fsck/dirinfo.c
@@ -155,6 +155,72 @@ static int e2fsck_dir_info_min_larger_equal(struct dir_info_db *dir_info,
 	return index;
 }
 
+/*
+ * Merge two sorted dir info to @dest
+ */
+void e2fsck_merge_dir_info(e2fsck_t ctx, struct dir_info_db *src,
+			   struct dir_info_db *dest)
+{
+	int		 size_dir_info = sizeof(struct dir_info);
+	int		 size = dest->size;
+	struct dir_info	*src_array = src->array;
+	struct dir_info	*dest_array = dest->array;
+	int		 src_count = src->count;
+	int		 dest_count = dest->count;
+	int		 total_count = src_count + dest_count;
+	struct dir_info	*array;
+	struct dir_info	*array_ptr;
+	int		 src_index = 0;
+	int		 dest_index = 0;
+
+	if (src->count == 0)
+		return;
+
+	if (size < total_count)
+		size = total_count;
+
+	if (size < src->size)
+		size = size;
+
+	array = e2fsck_allocate_memory(ctx, size * size_dir_info,
+				       "directory map");
+	array_ptr = array;
+	/*
+	 * This can be improved by binary search and memcpy, but codes
+	 * would be complexer. And if the groups distributed to each
+	 * thread are stided, this implementation won't be too bad comparing
+	 * to the optimiztion.
+	 */
+	while (src_index < src_count || dest_index < dest_count) {
+		if (src_index >= src_count) {
+			memcpy(array_ptr, &dest_array[dest_index],
+			       (dest_count - dest_index) * size_dir_info);
+			break;
+		}
+		if (dest_index >= dest_count) {
+			memcpy(array_ptr, &src_array[src_index],
+			       (src_count - src_index) * size_dir_info);
+			break;
+		}
+		if (src_array[src_index].ino < dest_array[dest_index].ino) {
+			*array_ptr = src_array[src_index];
+			src_index++;
+		} else {
+			assert(src_array[src_index].ino >
+			       dest_array[dest_index].ino);
+			*array_ptr = dest_array[dest_index];
+			dest_index++;
+		}
+		array_ptr++;
+	}
+
+	if (dest->array)
+		ext2fs_free_mem(&dest->array);
+	dest->array = array;
+	dest->size = size;
+	dest->count = total_count;
+}
+
 /*
  *
  * Insert an inode into the sorted array. The array should have at least one
diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
index 48afc8f3..f8e98f73 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -507,6 +507,8 @@ extern void read_bad_blocks_file(e2fsck_t ctx, const char *bad_blocks_file,
 
 /* dirinfo.c */
 extern void e2fsck_add_dir_info(e2fsck_t ctx, ext2_ino_t ino, ext2_ino_t parent);
+void e2fsck_merge_dir_info(e2fsck_t ctx, struct dir_info_db *src,
+                           struct dir_info_db *dest);
 extern void e2fsck_free_dir_info(e2fsck_t ctx);
 extern int e2fsck_get_num_dirinfo(e2fsck_t ctx);
 extern struct dir_info_iter *e2fsck_dir_info_iter_begin(e2fsck_t ctx);
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 85d18c55..56004c9b 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -2431,6 +2431,22 @@ out_context:
 	return retval;
 }
 
+static void e2fsck_pass1_merge_dir_info(e2fsck_t global_ctx, e2fsck_t thread_ctx)
+{
+	if (thread_ctx->dir_info == NULL)
+		return;
+
+	if (global_ctx->dir_info == NULL) {
+		/* TODO: tdb needs to be handled properly */
+		global_ctx->dir_info = thread_ctx->dir_info;
+		thread_ctx->dir_info = NULL;
+		return;
+	}
+
+	e2fsck_merge_dir_info(global_ctx, thread_ctx->dir_info,
+			      global_ctx->dir_info);
+}
+
 static int e2fsck_pass1_thread_join_one(e2fsck_t global_ctx, e2fsck_t thread_ctx)
 {
 	errcode_t	 retval;
@@ -2439,6 +2455,7 @@ static int e2fsck_pass1_thread_join_one(e2fsck_t global_ctx, e2fsck_t thread_ctx
 	ext2_filsys	 global_fs = global_ctx->fs;
 	FILE		*global_logf = global_ctx->logf;
 	FILE		*global_problem_logf = global_ctx->problem_logf;
+	struct dir_info_db *dir_info = global_ctx->dir_info;
 	ext2fs_inode_bitmap inode_used_map = global_ctx->inode_used_map;
 	ext2fs_inode_bitmap inode_dir_map = global_ctx->inode_dir_map;
 	ext2fs_inode_bitmap inode_bb_map = global_ctx->inode_bb_map;
@@ -2470,6 +2487,8 @@ static int e2fsck_pass1_thread_join_one(e2fsck_t global_ctx, e2fsck_t thread_ctx
 	global_ctx->block_dup_map = block_dup_map;
 	global_ctx->block_ea_map = block_ea_map;
 	global_ctx->block_metadata_map = block_metadata_map;
+	global_ctx->dir_info = dir_info;
+	e2fsck_pass1_merge_dir_info(global_ctx, thread_ctx);
 
 	/* Keep the global singal flags*/
 	global_ctx->flags |= (flags & E2F_FLAG_SIGNAL_MASK) |
