diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 60a30da..4338b00 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -568,6 +568,7 @@
 	fs_info->tree_root = tree_root;
 	fs_info->extent_root = extent_root;
 	fs_info->sb = sb;
+	fs_info->mount_opt = 0;
 	fs_info->btree_inode = new_inode(sb);
 	fs_info->btree_inode->i_ino = 1;
 	fs_info->btree_inode->i_nlink = 1;