diff --git a/src/sfs.rs b/src/sfs.rs
index adb4055..6e9bed3 100644
--- a/src/sfs.rs
+++ b/src/sfs.rs
@@ -120,12 +120,12 @@ impl INode {
         use vfs::INode;
         // Insert entries: '.' '..'
         self.resize(BLKSIZE * 2).unwrap();
-        self.write_at(0, DiskEntry {
+        self.write_at(BLKSIZE * 1, DiskEntry {
             id: parent as u32,
             name: Str256::from(".."),
         }.as_buf()).unwrap();
         let id = self.id as u32;
-        self.write_at(0, DiskEntry {
+        self.write_at(BLKSIZE * 0, DiskEntry {
             id,
             name: Str256::from("."),
         }.as_buf()).unwrap();
@@ -246,7 +246,7 @@ impl vfs::INode for INode {
         self.disk_inode.size = len as u32;
         Ok(())
     }
-    fn create(&mut self, name: &'static str) -> vfs::Result<Ptr<vfs::INode>> {
+    fn create(&mut self, name: &'static str, type_: vfs::FileType) -> vfs::Result<Ptr<vfs::INode>> {
         let fs = self.fs.upgrade().unwrap();
         let info = self.info().unwrap();
         assert_eq!(info.type_, vfs::FileType::Dir);
@@ -256,7 +256,10 @@ impl vfs::INode for INode {
         assert!(self.get_file_inode_id(name).is_none(), "file name exist");
 
         // Create new INode
-        let inode = fs.new_inode_file().unwrap();
+        let inode = match type_ {
+            vfs::FileType::File => fs.new_inode_file().unwrap(),
+            vfs::FileType::Dir => fs.new_inode_dir(self.id).unwrap(),
+        };
 
         // Write new entry
         let entry = DiskEntry {
@@ -287,7 +290,7 @@ impl vfs::INode for INode {
         let type_ = inode.borrow().disk_inode.type_;
         match type_ {
             FileType::File => if rest_path == "" {Ok(inode)} else {Err(())},
-            FileType::Dir => inode.borrow_mut().lookup(rest_path),
+            FileType::Dir => if rest_path == "" {Ok(inode)} else {inode.borrow().lookup(rest_path)},
             _ => unimplemented!(),
         }
     }
@@ -424,6 +427,7 @@ impl SimpleFileSystem {
         }
         fs
     }
+
     /// Allocate a block, return block id
     fn alloc_block(&self) -> Option<usize> {
         let id = self.free_map.borrow_mut().alloc();
@@ -481,8 +485,6 @@ impl SimpleFileSystem {
 }
 
 impl vfs::FileSystem for SimpleFileSystem {
-    type INode = INode;
-
     /// Write back super block if dirty
     fn sync(&self) -> vfs::Result<()> {
         {
@@ -506,7 +508,7 @@ impl vfs::FileSystem for SimpleFileSystem {
         Ok(())
     }
 
-    fn root_inode(&self) -> Ptr<INode> {
+    fn root_inode(&self) -> Ptr<vfs::INode> {
         self.get_inode(BLKN_ROOT)
     }
 }
diff --git a/src/tests.rs b/src/tests.rs
index 39fff5c..a4dcc26 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -35,7 +35,7 @@ fn _create_new_sfs() -> Rc<SimpleFileSystem> {
     let file = OpenOptions::new()
         .read(true).write(true).create(true).open("test.img")
         .expect("failed to create file");
-    SimpleFileSystem::create(Box::new(file), 16 * 4096)
+    SimpleFileSystem::create(Box::new(file), 32 * 4096)
 }
 
 #[test]
@@ -67,7 +67,7 @@ fn print_root() {
 fn create_file() {
     let sfs = _create_new_sfs();
     let root = sfs.root_inode();
-    let file1 = root.borrow_mut().create("file1").unwrap();
+    let file1 = root.borrow_mut().create("file1", FileType::File).unwrap();
 
     assert_eq!(file1.borrow().info().unwrap(), FileInfo {
         size: 0,
@@ -82,10 +82,21 @@ fn create_file() {
 fn lookup() {
     let sfs = _create_new_sfs();
     let root = sfs.root_inode();
-    let file1 = root.borrow_mut().create("file1").unwrap();
-    let found = root.borrow().lookup("file1").expect("lookup not found");
-    println!("{:?}", found.borrow());
-    println!("{:?}", file1.borrow());
-    assert!(Rc::ptr_eq(&found, &file1), "found wrong INode");
+
+    assert!(Rc::ptr_eq(&root.borrow().lookup(".").unwrap(), &root), "failed to find .");
+    assert!(Rc::ptr_eq(&root.borrow().lookup("..").unwrap(), &root), "failed to find ..");
+
+    let file1 = root.borrow_mut().create("file1", FileType::File)
+        .expect("failed to create file1");
+    assert!(Rc::ptr_eq(&root.borrow().lookup("file1").unwrap(), &file1), "failed to find file1");
+    assert!(root.borrow().lookup("file2").is_err(), "found non-existent file");
+
+    let dir1 = root.borrow_mut().create("dir1", FileType::Dir)
+        .expect("failed to create dir1");
+    let file2 = dir1.borrow_mut().create("file2", FileType::File)
+        .expect("failed to create /dir1/file2");
+    assert!(Rc::ptr_eq(&root.borrow().lookup("dir1/file2").unwrap(), &file2), "failed to find dir1/file1");
+    assert!(Rc::ptr_eq(&dir1.borrow().lookup("..").unwrap(), &root), "failed to find .. from dir1");
+
     sfs.sync().unwrap();
 }
\ No newline at end of file
diff --git a/src/vfs.rs b/src/vfs.rs
index d5cf004..1305016 100644
--- a/src/vfs.rs
+++ b/src/vfs.rs
@@ -16,7 +16,7 @@ pub trait INode: Debug {
 //    fn reclaim(&mut self) -> Result<()>;
 //    fn try_seek(&mut self, offset: u64) -> Result<()>;
     fn resize(&mut self, len: usize) -> Result<()>;
-    fn create(&mut self, name: &'static str) -> Result<Rc<RefCell<INode>>>;
+    fn create(&mut self, name: &'static str, type_: FileType) -> Result<Rc<RefCell<INode>>>;
     fn lookup(&self, path: &'static str) -> Result<Rc<RefCell<INode>>>;
 //    fn io_ctrl(&mut self, op: u32, data: &[u8]) -> Result<()>;
 }
@@ -37,9 +37,8 @@ pub type Result<T> = core::result::Result<T, ()>;
 
 /// Abstract filesystem
 pub trait FileSystem {
-    type INode: INode;
     fn sync(&self) -> Result<()>;
-    fn root_inode(&self) -> Rc<RefCell<Self::INode>>;
+    fn root_inode(&self) -> Rc<RefCell<INode>>;
 //    fn unmount(&self) -> Result<()>;
 //    fn cleanup(&self);
 }
\ No newline at end of file