diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a406f0ac5f74..6f388fee0eee 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6011,7 +6011,8 @@ static int btrfs_get_dir_last_index(struct btrfs_inode *dir, u64 *index)
 		}
 	}
 
-	*index = dir->index_cnt;
+	/* index_cnt is the index number of next new entry, so decrement it. */
+	*index = dir->index_cnt - 1;
 
 	return 0;
 }