fs/mem: make lstat compliant with POSIX

Author: zyuiop

src/fs/mem.rs

@@ -627,15 +627,17 @@ impl VfsNode for MemDirectory {
 		block_on(
 			async {
 				let (component, rest) = path.split_once("/").unwrap_or((path, ""));
+				let inner = self.inner.read().await;
+				let node = inner.get(component).ok_or(Errno::Badf)?;
 
 				if !rest.is_empty() {
-					let inner = self.inner.read().await;
-					let directory = inner.get(component).ok_or(Errno::Badf)?;
-					return directory.traverse_lstat(rest);
+					if node.get_kind() == NodeKind::File {
+						Err(Errno::Notdir)?;
+					}
+
+					return node.traverse_lstat(rest);
 				}
 
-				let inner = self.inner.read().await;
-				let node = inner.get(component).ok_or(Errno::Badf)?;
 				node.get_file_attributes()
 			},
 			None,
@@ -646,15 +648,17 @@ impl VfsNode for MemDirectory {
 		block_on(
 			async {
 				let (component, rest) = path.split_once("/").unwrap_or((path, ""));
+				let inner = self.inner.read().await;
+				let node = inner.get(component).ok_or(Errno::Badf)?;
 
 				if !rest.is_empty() {
-					let inner = self.inner.read().await;
-					let directory = inner.get(component).ok_or(Errno::Badf)?;
-					return directory.traverse_stat(rest);
+					if node.get_kind() == NodeKind::File {
+						Err(Errno::Notdir)?;
+					}
+
+					return node.traverse_stat(rest);
 				}
 
-				let inner = self.inner.read().await;
-				let node = inner.get(component).ok_or(Errno::Badf)?;
 				node.get_file_attributes()
 			},
 			None,