diff --git a/easy-fs/src/bin/main.rs b/easy-fs/src/bin/main.rs
index 1a8061fd..c7b313c4 100644
--- a/easy-fs/src/bin/main.rs
+++ b/easy-fs/src/bin/main.rs
@@ -55,5 +55,16 @@ fn easy_fs_pack() -> std::io::Result<()> {
     for name in root_inode.ls() {
         println!("{}", name);
     }
+    {
+        let filea = root_inode.find("filea").unwrap();
+        println!("writing filea!");
+        filea.write_at(0, "Hello, world!".as_bytes());
+    }
+    {
+        let filea = root_inode.find("filea").unwrap();
+        let mut buffer = [0u8; 512];
+        let len = filea.read_at(0, &mut buffer);
+        println!("{}", core::str::from_utf8(&buffer[..len]).unwrap());
+    }
     Ok(())
 }
\ No newline at end of file
diff --git a/easy-fs/src/layout.rs b/easy-fs/src/layout.rs
index d262f354..d173e0b0 100644
--- a/easy-fs/src/layout.rs
+++ b/easy-fs/src/layout.rs
@@ -276,4 +276,7 @@ impl DirEntry {
         let len = (0usize..).find(|i| self.name[*i] == 0).unwrap();
         core::str::from_utf8(&self.name[..len]).unwrap()
     }
+    pub fn inode_number(&self) -> u32 {
+        self.inode_number
+    }
 }
\ No newline at end of file
diff --git a/easy-fs/src/vfs.rs b/easy-fs/src/vfs.rs
index 415b289c..b544ac46 100644
--- a/easy-fs/src/vfs.rs
+++ b/easy-fs/src/vfs.rs
@@ -12,6 +12,7 @@ use alloc::sync::Arc;
 use alloc::string::String;
 use alloc::vec::Vec;
 use spin::{Mutex, MutexGuard};
+use crate::layout::DiskInodeType::Directory;
 
 pub struct Inode {
     inode_id: u32,
@@ -41,11 +42,13 @@ impl Inode {
         name: &str,
         inode: &Dirty<DiskInode>,
     ) -> Option<u32> {
+        println!("into find_inode_id");
         // assert it is a directory
         assert!(inode.read(|inode| inode.is_dir()));
         let file_count = inode.read(|inode| {
             inode.size as usize
         }) / DIRENT_SZ;
+        println!("file_count = {}", file_count);
         let mut dirent_space: DirentBytes = Default::default();
         for i in 0..file_count {
             assert_eq!(
@@ -58,8 +61,9 @@ impl Inode {
                 }),
                 DIRENT_SZ,
             );
-            if DirEntry::from_bytes(&dirent_space).name() == name {
-                return Some(i as u32);
+            let dirent = DirEntry::from_bytes(&dirent_space);
+            if dirent.name() == name {
+                return Some(dirent.inode_number() as u32);
             }
         }
         None
@@ -184,7 +188,7 @@ impl Inode {
         })
     }
 
-    pub fn write_at(&self, offset: usize, buf: &mut [u8]) -> usize {
+    pub fn write_at(&self, offset: usize, buf: &[u8]) -> usize {
         let mut fs = self.fs.lock();
         let mut inode = self.get_disk_inode(&mut fs);
         self.increase_size((offset + buf.len()) as u32, &mut inode, &mut fs);