Remove the shim kernel crate

kernel/src/fs/utils/fs.rs

@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: MPL-2.0
+
+use super::Inode;
+use crate::prelude::*;
+
+#[derive(Debug, Clone)]
+pub struct SuperBlock {
+    pub magic: u64,
+    pub bsize: usize,
+    pub blocks: usize,
+    pub bfree: usize,
+    pub bavail: usize,
+    pub files: usize,
+    pub ffree: usize,
+    pub fsid: u64,
+    pub namelen: usize,
+    pub frsize: usize,
+    pub flags: u64,
+}
+
+impl SuperBlock {
+    pub fn new(magic: u64, block_size: usize, name_max_len: usize) -> Self {
+        Self {
+            magic,
+            bsize: block_size,
+            blocks: 0,
+            bfree: 0,
+            bavail: 0,
+            files: 0,
+            ffree: 0,
+            fsid: 0,
+            namelen: name_max_len,
+            frsize: block_size,
+            flags: 0,
+        }
+    }
+}
+
+bitflags! {
+    pub struct FsFlags: u32 {
+        /// Dentry cannot be evicted.
+        const DENTRY_UNEVICTABLE = 1 << 1;
+    }
+}
+
+pub trait FileSystem: Any + Sync + Send {
+    fn sync(&self) -> Result<()>;
+
+    fn root_inode(&self) -> Arc<dyn Inode>;
+
+    fn sb(&self) -> SuperBlock;
+
+    fn flags(&self) -> FsFlags;
+}
+
+impl dyn FileSystem {
+    pub fn downcast_ref<T: FileSystem>(&self) -> Option<&T> {
+        (self as &dyn Any).downcast_ref::<T>()
+    }
+}
+
+impl Debug for dyn FileSystem {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        f.debug_struct("FileSystem")
+            .field("super_block", &self.sb())
+            .field("flags", &self.flags())
+            .finish()
+    }
+}