Substituted to the original ch7 code.

easy-fs/src/efs.rs

@@ -0,0 +1,163 @@
+use alloc::sync::Arc;
+use spin::Mutex;
+use super::{
+    BlockDevice,
+    Bitmap,
+    SuperBlock,
+    DiskInode,
+    DiskInodeType,
+    Inode,
+    get_block_cache,
+    block_cache_sync_all,
+};
+use crate::BLOCK_SZ;
+
+pub struct EasyFileSystem {
+    pub block_device: Arc<dyn BlockDevice>,
+    pub inode_bitmap: Bitmap,
+    pub data_bitmap: Bitmap,
+    inode_area_start_block: u32,
+    data_area_start_block: u32,
+}
+
+type DataBlock = [u8; BLOCK_SZ];
+
+impl EasyFileSystem {
+    pub fn create(
+        block_device: Arc<dyn BlockDevice>,
+        total_blocks: u32,
+        inode_bitmap_blocks: u32,
+    ) -> Arc<Mutex<Self>> {
+        // calculate block size of areas & create bitmaps
+        let inode_bitmap = Bitmap::new(1, inode_bitmap_blocks as usize);
+        let inode_num = inode_bitmap.maximum();
+        let inode_area_blocks =
+            ((inode_num * core::mem::size_of::<DiskInode>() + BLOCK_SZ - 1) / BLOCK_SZ) as u32;
+        let inode_total_blocks = inode_bitmap_blocks + inode_area_blocks;
+        let data_total_blocks = total_blocks - 1 - inode_total_blocks;
+        let data_bitmap_blocks = (data_total_blocks + 4096) / 4097;
+        let data_area_blocks = data_total_blocks - data_bitmap_blocks;
+        let data_bitmap = Bitmap::new(
+            (1 + inode_bitmap_blocks + inode_area_blocks) as usize,
+            data_bitmap_blocks as usize,
+        );
+        let mut efs = Self {
+            block_device: Arc::clone(&block_device),
+            inode_bitmap,
+            data_bitmap,
+            inode_area_start_block: 1 + inode_bitmap_blocks,
+            data_area_start_block: 1 + inode_total_blocks + data_bitmap_blocks,
+        };
+        // clear all blocks
+        for i in 0..total_blocks {
+            get_block_cache(
+                i as usize,
+                Arc::clone(&block_device)
+            )
+            .lock()
+            .modify(0, |data_block: &mut DataBlock| {
+                for byte in data_block.iter_mut() { *byte = 0; }
+            });
+        }
+        // initialize SuperBlock
+        get_block_cache(0, Arc::clone(&block_device))
+        .lock()
+        .modify(0, |super_block: &mut SuperBlock| {
+            super_block.initialize(
+                total_blocks,
+                inode_bitmap_blocks,
+                inode_area_blocks,
+                data_bitmap_blocks,
+                data_area_blocks,
+            );
+        });
+        // write back immediately
+        // create a inode for root node "/"
+        assert_eq!(efs.alloc_inode(), 0);
+        let (root_inode_block_id, root_inode_offset) = efs.get_disk_inode_pos(0);
+        get_block_cache(
+            root_inode_block_id as usize,
+            Arc::clone(&block_device)
+        )
+        .lock()
+        .modify(root_inode_offset, |disk_inode: &mut DiskInode| {
+            disk_inode.initialize(DiskInodeType::Directory);
+        });
+        block_cache_sync_all();
+        Arc::new(Mutex::new(efs))
+    }
+
+    pub fn open(block_device: Arc<dyn BlockDevice>) -> Arc<Mutex<Self>> {
+        // read SuperBlock
+        get_block_cache(0, Arc::clone(&block_device))
+            .lock()
+            .read(0, |super_block: &SuperBlock| {
+                assert!(super_block.is_valid(), "Error loading EFS!");
+                let inode_total_blocks =
+                    super_block.inode_bitmap_blocks + super_block.inode_area_blocks;
+                let efs = Self {
+                    block_device,
+                    inode_bitmap: Bitmap::new(
+                        1,
+                        super_block.inode_bitmap_blocks as usize
+                    ),
+                    data_bitmap: Bitmap::new(
+                        (1 + inode_total_blocks) as usize,
+                        super_block.data_bitmap_blocks as usize,
+                    ),
+                    inode_area_start_block: 1 + super_block.inode_bitmap_blocks,
+                    data_area_start_block: 1 + inode_total_blocks + super_block.data_bitmap_blocks,
+                };
+                Arc::new(Mutex::new(efs))
+            })
+    }
+
+    pub fn root_inode(efs: &Arc<Mutex<Self>>) -> Inode {
+        let block_device = Arc::clone(&efs.lock().block_device);
+        // acquire efs lock temporarily
+        let (block_id, block_offset) = efs.lock().get_disk_inode_pos(0);
+        // release efs lock
+        Inode::new(
+            block_id,
+            block_offset,
+            Arc::clone(efs),
+            block_device,
+        )
+    }
+
+    pub fn get_disk_inode_pos(&self, inode_id: u32) -> (u32, usize) {
+        let inode_size = core::mem::size_of::<DiskInode>();
+        let inodes_per_block = (BLOCK_SZ / inode_size) as u32;
+        let block_id = self.inode_area_start_block + inode_id / inodes_per_block;
+        (block_id, (inode_id % inodes_per_block) as usize * inode_size)
+    }
+
+    pub fn get_data_block_id(&self, data_block_id: u32) -> u32 {
+        self.data_area_start_block + data_block_id
+    }
+
+    pub fn alloc_inode(&mut self) -> u32 {
+        self.inode_bitmap.alloc(&self.block_device).unwrap() as u32
+    }
+
+    /// Return a block ID not ID in the data area.
+    pub fn alloc_data(&mut self) -> u32 {
+        self.data_bitmap.alloc(&self.block_device).unwrap() as u32 + self.data_area_start_block
+    }
+
+    pub fn dealloc_data(&mut self, block_id: u32) {
+        get_block_cache(
+            block_id as usize,
+            Arc::clone(&self.block_device)
+        )
+        .lock()
+        .modify(0, |data_block: &mut DataBlock| {
+            data_block.iter_mut().for_each(|p| { *p = 0; })
+        });
+        self.data_bitmap.dealloc(
+            &self.block_device,
+            (block_id - self.data_area_start_block) as usize
+        )
+    }
+
+}