Make ext2 handle fifo and devices correctly

kernel/src/fs/ext2/impl_for_vfs/inode.rs

@@ -2,14 +2,18 @@
 
 use core::time::Duration;
 
+use device_id::DeviceId;
+
 use crate::{
+    device::get_device,
     fs::{
         ext2::{FilePerm, Inode as Ext2Inode},
+        inode_handle::FileIo,
         notify::FsEventPublisher,
         utils::{
-            DirentVisitor, Extension, FallocMode, FileSystem, Inode, InodeIo, InodeMode, InodeType,
-            Metadata, MknodType, StatusFlags, SymbolicLink, XattrName, XattrNamespace,
-            XattrSetFlags,
+            AccessMode, DirentVisitor, Extension, FallocMode, FileSystem, Inode, InodeIo,
+            InodeMode, InodeType, Metadata, MknodType, StatusFlags, SymbolicLink, XattrName,
+            XattrNamespace, XattrSetFlags,
         },
     },
     prelude::*,
@@ -121,6 +125,25 @@ impl Inode for Ext2Inode {
         Some(self.page_cache())
     }
 
+    fn open(
+        &self,
+        access_mode: AccessMode,
+        status_flags: StatusFlags,
+    ) -> Option<Result<Box<dyn FileIo>>> {
+        match self.inode_type() {
+            InodeType::BlockDevice | InodeType::CharDevice => {
+                let device_id = self.device_id();
+                let device = match get_device(DeviceId::from_encoded_u64(device_id)) {
+                    Ok(device) => device,
+                    Err(e) => return Some(Err(e)),
+                };
+                Some(device.open())
+            }
+            InodeType::NamedPipe => Some(self.open_named_pipe(access_mode, status_flags)),
+            _ => None,
+        }
+    }
+
     fn create(&self, name: &str, type_: InodeType, mode: InodeMode) -> Result<Arc<dyn Inode>> {
         Ok(self.create(name, type_, mode.into())?)
     }
@@ -133,7 +156,7 @@ impl Inode for Ext2Inode {
                 inode.set_device_id(dev.id().as_encoded_u64()).unwrap();
                 inode
             }
-            _ => todo!(),
+            MknodType::NamedPipe => self.create(name, inode_type, mode.into())?,
         };
 
         Ok(inode)

kernel/src/fs/ext2/inode.rs

@@ -20,11 +20,13 @@ use super::{
 };
 use crate::{
     fs::{
+        inode_handle::FileIo,
         notify::FsEventPublisher,
         path::{is_dot, is_dot_or_dotdot, is_dotdot},
+        pipe::NamedPipe,
         utils::{
-            Extension, FallocMode, Inode as _, InodeMode, Metadata, Permission, XattrName,
-            XattrNamespace, XattrSetFlags,
+            AccessMode, Extension, FallocMode, Inode as _, InodeMode, Metadata, Permission,
+            StatusFlags, XattrName, XattrNamespace, XattrSetFlags,
         },
     },
     process::{posix_thread::AsPosixThread, Gid, Uid},
@@ -688,6 +690,16 @@ impl Inode {
         inner.device_id()
     }
 
+    pub(super) fn open_named_pipe(
+        &self,
+        access_mode: AccessMode,
+        status_flags: StatusFlags,
+    ) -> Result<Box<dyn FileIo>> {
+        let inner = self.inner.read();
+        let named_pipe = inner.named_pipe.as_ref().unwrap();
+        named_pipe.open(access_mode, status_flags)
+    }
+
     pub fn read_at(&self, offset: usize, writer: &mut VmWriter) -> Result<usize> {
         if self.type_ != InodeType::File {
             return_errno!(Errno::EISDIR);
@@ -960,11 +972,19 @@ fn write_lock_multiple_inodes(inodes: Vec<&Inode>) -> Vec<RwMutexWriteGuard<'_,
 struct InodeInner {
     inode_impl: InodeImpl,
     page_cache: PageCache,
+    // This corresponds to the `i_pipe` field in `struct inode` in Linux.
+    // Reference: <https://elixir.bootlin.com/linux/v6.17/source/include/linux/fs.h#L771>.
+    named_pipe: Option<NamedPipe>,
 }
 
 impl InodeInner {
     pub fn new(desc: Dirty<InodeDesc>, weak_self: Weak<Inode>, fs: Weak<Ext2>) -> Self {
         let num_page_bytes = desc.num_page_bytes();
+        let named_pipe = if desc.type_ == InodeType::NamedPipe {
+            Some(NamedPipe::new())
+        } else {
+            None
+        };
         let inode_impl = InodeImpl::new(desc, weak_self, fs);
         Self {
             page_cache: PageCache::with_capacity(
@@ -973,6 +993,7 @@ impl InodeInner {
             )
             .unwrap(),
             inode_impl,
+            named_pipe,
         }
     }
 

kernel/src/fs/pipe/named_pipe.rs

@@ -134,11 +134,11 @@ pub struct NamedPipe {
 
 impl NamedPipe {
     /// Creates a new named pipe.
-    pub fn new() -> Result<Self> {
-        Ok(Self {
+    pub fn new() -> Self {
+        Self {
             pipe: Mutex::new(NamedPipeInner::default()),
             wait_queue: WaitQueue::new(),
-        })
+        }
     }
 
     /// Opens the named pipe with the specified access mode and status flags.

kernel/src/fs/ramfs/fs.rs

@@ -154,7 +154,7 @@ impl Inner {
     }
 
     pub(self) fn new_named_pipe() -> Self {
-        Self::NamedPipe(NamedPipe::new().unwrap())
+        Self::NamedPipe(NamedPipe::new())
     }
 
     pub(self) fn new_file_in_memfd(this: Weak<MemfdInode>) -> Self {