implement truncation

Cargo.lock

@@ -92,7 +92,7 @@ dependencies = [
 [[package]]
 name = "ext4-view"
 version = "0.9.3"
-source = "git+https://github.com/arihant2math/ext4-view-rs.git?branch=main#adb7c88dd8acba198f8c701e664b2a03ca9df339"
+source = "git+https://github.com/arihant2math/ext4-view-rs.git?branch=main#6408b7de5947ac04cfce03579b586ec8b5fa0d6d"
 dependencies = [
  "async-trait",
  "bitflags",
@@ -430,9 +430,9 @@ dependencies = [
 
 [[package]]
 name = "rand_core"
-version = "0.9.3"
+version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99d9a13982dcf210057a8a78572b2217b667c3beacbf3a0d8b454f6f82837d38"
+checksum = "76afc826de14238e6e8c374ddcc1fa19e374fd8dd986b0d2af0d02377261d83c"
 dependencies = [
  "getrandom",
 ]
@@ -606,9 +606,9 @@ checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
 
 [[package]]
 name = "wasip2"
-version = "1.0.1+wasi-0.2.4"
+version = "1.0.2+wasi-0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0562428422c63773dad2c345a1882263bbf4d65cf3f42e90921f787ef5ad58e7"
+checksum = "9517f9239f02c069db75e65f174b3da828fe5f5b945c4dd26bd25d89c03ebcf5"
 dependencies = [
  "wit-bindgen",
 ]
@@ -704,9 +704,9 @@ checksum = "d6bbff5f0aada427a1e5a6da5f1f98158182f26556f345ac9e04d36d0ebed650"
 
 [[package]]
 name = "wit-bindgen"
-version = "0.46.0"
+version = "0.51.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f17a85883d4e6d00e8a97c586de764dabcc06133f7f1d55dce5cdc070ad7fe59"
+checksum = "d7249219f66ced02969388cf2bb044a09756a083d0fab1e566056b04d9fbcaa5"
 
 [[package]]
 name = "zerocopy"

libkernel/src/fs/filesystems/ext4/mod.rs

@@ -220,8 +220,15 @@ where
         Ok(total_written)
     }
 
-    async fn truncate(&self, _size: u64) -> Result<()> {
-        Err(KernelError::NotSupported)
+    async fn truncate(&self, size: u64) -> Result<()> {
+        let inner = self.inner.lock().await;
+        if inner.metadata.file_type != ext4_view::FileType::Regular {
+            return Err(KernelError::NotSupported);
+        }
+        let fs = self.fs_ref.upgrade().unwrap();
+        let mut file = File::open_inode(&fs.inner, inner.clone())?;
+        file.truncate(size).await?;
+        Ok(())
     }
 
     async fn getattr(&self) -> Result<FileAttr> {