From f57a54aa0dce4905b70023077a68a0b32cd6ab04 Mon Sep 17 00:00:00 2001
From: Ruihan Li <lrh2000@pku.edu.cn>
Date: Wed, 12 Nov 2025 17:47:28 +0800
Subject: [PATCH] Remove `AccessMode` from `InodeHandle`

---
 kernel/src/fs/inode_handle/dyn_cap.rs | 10 +++++-----
 kernel/src/fs/inode_handle/mod.rs     | 18 ++++++------------
 kernel/src/fs/utils/access_mode.rs    | 16 ++++++++++++++++
 3 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/kernel/src/fs/inode_handle/dyn_cap.rs b/kernel/src/fs/inode_handle/dyn_cap.rs
index 28c26f136..d41070464 100644
--- a/kernel/src/fs/inode_handle/dyn_cap.rs
+++ b/kernel/src/fs/inode_handle/dyn_cap.rs
@@ -40,13 +40,11 @@ impl InodeHandle {
 
     pub fn new_unchecked_access(
         path: Path,
-        mut access_mode: AccessMode,
+        access_mode: AccessMode,
         status_flags: StatusFlags,
     ) -> Result<Self> {
         let inode = path.inode();
         let (file_io, rights) = if status_flags.contains(StatusFlags::O_PATH) {
-            // We follow Linux to report O_RDONLY later (e.g., in `/proc/[pid]/fdinfo/[n]`).
-            access_mode = AccessMode::O_RDONLY;
             (None, Rights::empty())
         } else if inode.type_() == InodeType::Dir && access_mode.is_writable() {
             return_errno_with_message!(Errno::EISDIR, "a directory cannot be opened writable");
@@ -60,7 +58,6 @@ impl InodeHandle {
             path,
             file_io,
             offset: Mutex::new(0),
-            access_mode,
             status_flags: AtomicU32::new(status_flags.bits()),
         };
         Ok(Self(inner, rights))
@@ -133,7 +130,6 @@ impl Pollable for InodeHandle {
 #[inherit_methods(from = "self.0")]
 impl FileLike for InodeHandle {
     fn status_flags(&self) -> StatusFlags;
-    fn access_mode(&self) -> AccessMode;
     fn metadata(&self) -> Metadata;
     fn mode(&self) -> Result<InodeMode>;
     fn set_mode(&self, mode: InodeMode) -> Result<()>;
@@ -199,6 +195,10 @@ impl FileLike for InodeHandle {
         Ok(())
     }
 
+    fn access_mode(&self) -> AccessMode {
+        self.1.into()
+    }
+
     fn seek(&self, seek_from: SeekFrom) -> Result<usize> {
         if self.1.is_empty() {
             return_errno_with_message!(Errno::EBADF, "the file is opened as a path");
diff --git a/kernel/src/fs/inode_handle/mod.rs b/kernel/src/fs/inode_handle/mod.rs
index 86c87a556..305cd2d85 100644
--- a/kernel/src/fs/inode_handle/mod.rs
+++ b/kernel/src/fs/inode_handle/mod.rs
@@ -15,9 +15,9 @@ use crate::{
         file_handle::Mappable,
         path::Path,
         utils::{
-            AccessMode, DirentVisitor, FallocMode, FileRange, FlockItem, FlockList, Inode,
-            InodeMode, InodeType, IoctlCmd, Metadata, RangeLockItem, RangeLockList, RangeLockType,
-            SeekFrom, StatusFlags, OFFSET_MAX,
+            DirentVisitor, FallocMode, FileRange, FlockItem, FlockList, Inode, InodeMode,
+            InodeType, IoctlCmd, Metadata, RangeLockItem, RangeLockList, RangeLockType, SeekFrom,
+            StatusFlags, OFFSET_MAX,
         },
     },
     prelude::*,
@@ -29,12 +29,11 @@ use crate::{
 
 struct HandleInner {
     path: Path,
-    /// `file_io` is Similar to `file_private` field in `file` structure in linux. If
-    /// `file_io` is Some, typical file operations including `read`, `write`, `poll`,
-    /// `ioctl` will be provided by `file_io`, instead of `path`.
+    /// `file_io` is similar to the `file_private` field in Linux's `file` structure. If `file_io`
+    /// is `Some(_)`, typical file operations including `read`, `write`, `poll`, and `ioctl` will
+    /// be provided by `file_io`, instead of `path`.
     file_io: Option<Arc<dyn FileIo>>,
     offset: Mutex<usize>,
-    access_mode: AccessMode,
     status_flags: AtomicU32,
 }
 
@@ -120,10 +119,6 @@ impl HandleInner {
         do_resize_util(self.path.inode().as_ref(), self.status_flags(), new_size)
     }
 
-    pub(self) fn access_mode(&self) -> AccessMode {
-        self.access_mode
-    }
-
     pub(self) fn status_flags(&self) -> StatusFlags {
         let bits = self.status_flags.load(Ordering::Relaxed);
         StatusFlags::from_bits(bits).unwrap()
@@ -278,7 +273,6 @@ impl Debug for HandleInner {
         f.debug_struct("HandleInner")
             .field("path", &self.path)
             .field("offset", &self.offset())
-            .field("access_mode", &self.access_mode())
             .field("status_flags", &self.status_flags())
             .finish_non_exhaustive()
     }
diff --git a/kernel/src/fs/utils/access_mode.rs b/kernel/src/fs/utils/access_mode.rs
index 82342f603..6404e16c1 100644
--- a/kernel/src/fs/utils/access_mode.rs
+++ b/kernel/src/fs/utils/access_mode.rs
@@ -38,6 +38,22 @@ impl AccessMode {
     }
 }
 
+impl From<Rights> for AccessMode {
+    fn from(rights: Rights) -> Self {
+        match (
+            rights.contains(Rights::READ),
+            rights.contains(Rights::WRITE),
+        ) {
+            (true, true) => AccessMode::O_RDWR,
+            (true, false) => AccessMode::O_RDONLY,
+            (false, true) => AccessMode::O_WRONLY,
+            // The file is opened with `O_PATH`. We follow Linux to report `O_RDONLY` here (e.g.,
+            // in `/proc/[pid]/fdinfo/[n]`).
+            (false, false) => AccessMode::O_RDONLY,
+        }
+    }
+}
+
 impl From<AccessMode> for Rights {
     fn from(access_mode: AccessMode) -> Rights {
         match access_mode {