create & open efs.

easy-fs/src/layout.rs

@@ -0,0 +1,80 @@
+use core::fmt::{Debug, Formatter, Result};
+
+const EFS_MAGIC: u32 = 0x3b800001;
+const INODE_DIRECT_COUNT: usize = 12;
+const NAME_LENGTH_LIMIT: usize = 27;
+
+#[repr(C)]
+pub struct SuperBlock {
+    magic: u32,
+    pub total_blocks: u32,
+    pub inode_bitmap_blocks: u32,
+    pub inode_area_blocks: u32,
+    pub data_bitmap_blocks: u32,
+    pub data_area_blocks: u32,
+}
+
+impl Debug for SuperBlock {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        f.debug_struct("SuperBlock")
+            .field("total_blocks", &self.total_blocks)
+            .field("inode_bitmap_blocks", &self.inode_bitmap_blocks)
+            .field("inode_area_blocks", &self.inode_area_blocks)
+            .field("data_bitmap_blocks", &self.data_bitmap_blocks)
+            .field("data_area_blocks", &self.data_area_blocks)
+            .finish()
+    }
+}
+
+impl SuperBlock {
+    pub fn initialize(
+        &mut self,
+        total_blocks: u32,
+        inode_bitmap_blocks: u32,
+        inode_area_blocks: u32,
+        data_bitmap_blocks: u32,
+        data_area_blocks: u32,
+    ) {
+        *self = Self {
+            magic: EFS_MAGIC,
+            total_blocks,
+            inode_bitmap_blocks,
+            inode_area_blocks,
+            data_bitmap_blocks,
+            data_area_blocks,
+        }
+    }
+    pub fn is_valid(&self) -> bool {
+        self.magic == EFS_MAGIC
+    }
+}
+
+pub enum DiskInodeType {
+    File,
+    Directory,
+}
+
+#[repr(C)]
+pub struct DiskInode {
+    size: u32,
+    direct: [u32; INODE_DIRECT_COUNT],
+    indirect1: u32,
+    indirect2: u32,
+    type_: DiskInodeType,
+}
+
+impl DiskInode {
+    pub fn initialize(&mut self, type_: DiskInodeType) {
+        self.size = 0;
+        self.direct.iter_mut().for_each(|v| *v = 0);
+        self.indirect1 = 0;
+        self.indirect2 = 0;
+        self.type_ = type_;
+    }
+}
+
+#[repr(C)]
+pub struct DirEntry {
+    name: [u8; NAME_LENGTH_LIMIT + 1],
+    inode_number: u32,
+}