We need BlockCache.

easy-fs/src/bin/main.rs

@@ -4,6 +4,7 @@ extern crate alloc;
 use easy_fs::{
     BlockDevice,
     EasyFileSystem,
+    Inode,
 };
 use std::fs::{File, OpenOptions};
 use std::io::{Read, Write, Seek, SeekFrom};
@@ -16,6 +17,7 @@ struct BlockFile(Mutex<File>);
 
 impl BlockDevice for BlockFile {
     fn read_block(&self, block_id: usize, buf: &mut [u8]) {
+        println!("reading block {}", block_id);
         let mut file = self.0.lock().unwrap();
         file.seek(SeekFrom::Start((block_id * BLOCK_SZ) as u64))
             .expect("Error when seeking!");
@@ -23,6 +25,7 @@ impl BlockDevice for BlockFile {
     }
 
     fn write_block(&self, block_id: usize, buf: &[u8]) {
+        println!("writing block {}", block_id);
         let mut file = self.0.lock().unwrap();
         file.seek(SeekFrom::Start((block_id * BLOCK_SZ) as u64))
             .expect("Error when seeking!");
@@ -35,19 +38,23 @@ fn main() {
 }
 
 fn easy_fs_pack() -> std::io::Result<()> {
-    let block_file = BlockFile(Mutex::new(
+    let block_file = Arc::new(BlockFile(Mutex::new(
         OpenOptions::new()
             .read(true)
             .write(true)
             .open("target/fs.img")?
-    ));
-    /*
-    let _efs = EasyFileSystem::create(
-        Arc::new(block_file),
+    )));
+    EasyFileSystem::create(
+        block_file.clone(),
         4096,
         1,
     );
-     */
-    let _efs = EasyFileSystem::open(Arc::new(block_file));
+    let efs = EasyFileSystem::open(block_file.clone());
+    let mut root_inode = EasyFileSystem::root_inode(&efs);
+    root_inode.create("filea");
+    root_inode.create("fileb");
+    for name in root_inode.ls() {
+        println!("name");
+    }
     Ok(())
 }

easy-fs/src/dirty.rs

@@ -7,6 +7,7 @@ pub struct Dirty<T> {
     block_id: usize,
     block_cache: [u8; BLOCK_SZ],
     offset: usize,
+    dirty: bool,
     block_device: Arc<dyn BlockDevice>,
     phantom: PhantomData<T>,
 }
@@ -21,29 +22,37 @@ impl<T> Dirty<T> where T: Sized {
                 cache
             },
             offset,
+            dirty: false,
             block_device,
             phantom: PhantomData,
         }
     }
     pub fn get_mut(&mut self) -> &mut T {
+        self.dirty = true;
         let type_size = core::mem::size_of::<T>();
         // assert that the struct is inside a block
         assert!(self.offset + type_size <= BLOCK_SZ);
         let start_addr = &self.block_cache[self.offset] as *const _ as usize;
         unsafe { &mut *(start_addr as *mut T) }
     }
-    pub fn read(&self) -> &T {
+    pub fn get_ref(&self) -> &T {
         let type_size = core::mem::size_of::<T>();
         // assert that the struct is inside a block
         assert!(self.offset + type_size <= BLOCK_SZ);
         let start_addr = &self.block_cache[self.offset] as *const _ as usize;
         unsafe { &*(start_addr as *const T) }
     }
-    pub fn modify(&mut self, f: impl Fn(&mut T)) {
+    pub fn read<V>(&self, f: impl FnOnce(&T) -> V) -> V {
+        f(self.get_ref())
+    }
+    pub fn modify(&mut self, f: impl FnOnce(&mut T)) {
         f(self.get_mut());
     }
     pub fn write_back(&mut self) {
-        self.block_device.write_block(self.block_id as usize, &self.block_cache);
+        if self.dirty {
+            self.block_device
+                .write_block(self.block_id as usize, &self.block_cache);
+        }
     }
 }
 

easy-fs/src/efs.rs

@@ -1,4 +1,5 @@
 use alloc::sync::Arc;
+use spin::Mutex;
 use super::{
     BlockDevice,
     Bitmap,
@@ -6,6 +7,7 @@ use super::{
     DiskInode,
     DiskInodeType,
     Dirty,
+    Inode,
 };
 use crate::BLOCK_SZ;
 
@@ -24,7 +26,7 @@ impl EasyFileSystem {
         block_device: Arc<dyn BlockDevice>,
         total_blocks: u32,
         inode_bitmap_blocks: u32,
-    ) -> Self {
+    ) -> 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();
@@ -38,7 +40,7 @@ impl EasyFileSystem {
             (1 + inode_bitmap_blocks + inode_area_blocks) as usize,
             data_bitmap_blocks as usize,
         );
-        let efs = Self {
+        let mut efs = Self {
             block_device,
             inode_bitmap,
             data_bitmap,
@@ -65,17 +67,20 @@ impl EasyFileSystem {
         });
         // write back immediately
         // create a inode for root node "/"
-        assert_eq!(efs.inode_bitmap.alloc(&efs.block_device).unwrap(), 0);
+        assert_eq!(efs.alloc_inode(), 0);
         efs.get_disk_inode(0).modify(|disk_inode| {
-            disk_inode.initialize(DiskInodeType::Directory);
+            disk_inode.initialize(
+                DiskInodeType::Directory,
+                efs.alloc_data(),
+            );
         });
-        efs
+        Arc::new(Mutex::new(efs))
     }
 
-    pub fn open(block_device: Arc<dyn BlockDevice>) -> Self {
+    pub fn open(block_device: Arc<dyn BlockDevice>) -> Arc<Mutex<Self>> {
         // read SuperBlock
         let super_block_dirty: Dirty<SuperBlock> = Dirty::new(0, 0, block_device.clone());
-        let super_block = super_block_dirty.read();
+        let super_block = super_block_dirty.get_ref();
         assert!(super_block.is_valid(), "Error loading EFS!");
         println!("{:?}", super_block);
         let inode_total_blocks =
@@ -93,14 +98,22 @@ impl EasyFileSystem {
             inode_area_start_block: 1 + super_block.inode_bitmap_blocks,
             data_area_start_block: 1 + inode_total_blocks + super_block.data_bitmap_blocks,
         };
-        efs
+        Arc::new(Mutex::new(efs))
+    }
+
+    pub fn root_inode(efs: &Arc<Mutex<Self>>) -> Inode {
+        Inode::new(
+            0,
+            efs.clone(),
+            efs.lock().block_device.clone(),
+        )
     }
 
     fn get_super_block(&self) -> Dirty<SuperBlock> {
         Dirty::new(0, 0, self.block_device.clone())
     }
 
-    fn get_disk_inode(&self, inode_id: u32) -> Dirty<DiskInode> {
+    pub fn get_disk_inode(&self, inode_id: u32) -> Dirty<DiskInode> {
         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;
@@ -111,12 +124,8 @@ impl EasyFileSystem {
         )
     }
 
-    fn get_data_block(&self, data_block_id: u32) -> Dirty<DataBlock> {
-        Dirty::new(
-            (self.data_area_start_block + data_block_id) as usize,
-            0,
-            self.block_device.clone(),
-        )
+    pub fn get_data_block(&self, data_block_id: u32) -> Dirty<DataBlock> {
+        self.get_block(self.data_area_start_block + data_block_id)
     }
 
     fn get_block(&self, block_id: u32) -> Dirty<DataBlock> {
@@ -127,4 +136,20 @@ impl EasyFileSystem {
         )
     }
 
+    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
+    }
+
+    fn dealloc_data(&mut self, block_id: u32) {
+        self.data_bitmap.dealloc(
+            &self.block_device,
+            (block_id - self.data_area_start_block) as usize
+        )
+    }
+
 }

easy-fs/src/layout.rs

@@ -1,4 +1,11 @@
 use core::fmt::{Debug, Formatter, Result};
+use super::{
+    BLOCK_SZ,
+    BlockDevice,
+    Dirty,
+};
+use alloc::sync::Arc;
+use alloc::vec::Vec;
 
 const EFS_MAGIC: u32 = 0x3b800001;
 const INODE_DIRECT_COUNT: usize = 12;
@@ -49,32 +56,224 @@ impl SuperBlock {
     }
 }
 
+#[derive(PartialEq)]
 pub enum DiskInodeType {
     File,
     Directory,
 }
 
+type IndirectBlock = [u32; BLOCK_SZ / 4];
+type DataBlock = [u8; BLOCK_SZ];
+
 #[repr(C)]
+/// Only support level-1 indirect now, **indirect2** field is always 0.
 pub struct DiskInode {
-    size: u32,
-    direct: [u32; INODE_DIRECT_COUNT],
-    indirect1: u32,
-    indirect2: u32,
+    pub size: u32,
+    pub direct: [u32; INODE_DIRECT_COUNT],
+    pub indirect1: u32,
+    pub indirect2: u32,
     type_: DiskInodeType,
 }
 
 impl DiskInode {
-    pub fn initialize(&mut self, type_: DiskInodeType) {
+    /// indirect1 block is allocated when the file is created.
+    pub fn initialize(&mut self, type_: DiskInodeType, indirect1: u32) {
         self.size = 0;
         self.direct.iter_mut().for_each(|v| *v = 0);
-        self.indirect1 = 0;
+        self.indirect1 = indirect1;
         self.indirect2 = 0;
         self.type_ = type_;
     }
+    pub fn is_dir(&self) -> bool {
+        self.type_ == DiskInodeType::Directory
+    }
+    pub fn is_file(&self) -> bool {
+        self.type_ == DiskInodeType::File
+    }
+    pub fn blocks(&self) -> u32 {
+        Self::_blocks(self.size)
+    }
+    fn _blocks(size: u32) -> u32 {
+        (size + BLOCK_SZ as u32 - 1) / BLOCK_SZ as u32
+    }
+    pub fn get_block_id(&self, inner_id: u32, block_device: &Arc<dyn BlockDevice>) -> u32 {
+        let inner_id = inner_id as usize;
+        if inner_id < INODE_DIRECT_COUNT {
+            self.direct[inner_id]
+        } else {
+            // only support indirect1 now
+            Dirty::<IndirectBlock>::new(
+                self.indirect1 as usize,
+                0,
+                block_device.clone()
+            ).read(|indirect_block| {
+                // it will panic if file is too large
+                indirect_block[inner_id - INODE_DIRECT_COUNT]
+            })
+        }
+    }
+    pub fn blocks_num_needed(&self, new_size: u32) -> u32 {
+        assert!(new_size >= self.size);
+        Self::_blocks(new_size) - self.blocks()
+    }
+    pub fn increase_size(
+        &mut self,
+        new_size: u32,
+        new_blocks: Vec<u32>,
+        block_device: &Arc<dyn BlockDevice>,
+    ) {
+        println!("increase_size new_size={}, new_blocks={:?}", new_size, new_blocks);
+        assert_eq!(new_blocks.len() as u32, self.blocks_num_needed(new_size));
+        let last_blocks = self.blocks();
+        self.size = new_size;
+        let current_blocks = self.blocks();
+        Dirty::<IndirectBlock>::new(
+            self.indirect1 as usize,
+            0,
+            block_device.clone()
+        ).modify(|indirect_block| {
+            for i in 0..current_blocks - last_blocks {
+                let inner_id = (last_blocks + i) as usize;
+                let new_block = new_blocks[i as usize];
+                if inner_id < INODE_DIRECT_COUNT {
+                    self.direct[inner_id] = new_block;
+                } else {
+                    indirect_block[inner_id - INODE_DIRECT_COUNT] = new_block;
+                }
+            }
+        });
+    }
+    /// Clear size to zero and return blocks that should be deallocated.
+    pub fn clear_size(&mut self, block_device: &Arc<dyn BlockDevice>) -> Vec<u32> {
+        let mut v: Vec<u32> = Vec::new();
+        let blocks = self.blocks() as usize;
+        self.size = 0;
+        for i in 0..blocks.min(INODE_DIRECT_COUNT) {
+            v.push(self.direct[i]);
+            self.direct[i] = 0;
+        }
+        if blocks > INODE_DIRECT_COUNT {
+            Dirty::<IndirectBlock>::new(
+                self.indirect1 as usize,
+                0,
+                block_device.clone(),
+            ).modify(|indirect_block| {
+                for i in 0..blocks - INODE_DIRECT_COUNT {
+                    v.push(indirect_block[i]);
+                    indirect_block[i] = 0;
+                }
+            });
+        }
+        v
+    }
+    pub fn read_at(
+        &self,
+        offset: usize,
+        buf: &mut [u8],
+        block_device: &Arc<dyn BlockDevice>,
+    ) -> usize {
+        let mut start = offset;
+        let end = (offset + buf.len()).min(self.size as usize);
+        if start >= end {
+            return 0;
+        }
+        let mut start_block = start / BLOCK_SZ;
+        let mut read_size = 0usize;
+        loop {
+            // calculate end of current block
+            let mut end_current_block = (start / BLOCK_SZ + 1) * BLOCK_SZ;
+            end_current_block = end_current_block.min(end);
+            // read and update read size
+            let block_read_size = end_current_block - start;
+            let dst = &mut buf[read_size..read_size + block_read_size];
+            Dirty::<DataBlock>::new(
+                self.get_block_id(start_block as u32, block_device) as usize,
+                0,
+                block_device.clone()
+            ).read(|data_block| {
+                let src = &data_block[start % BLOCK_SZ..start % BLOCK_SZ + block_read_size];
+                dst.copy_from_slice(src);
+            });
+            read_size += block_read_size;
+            // move to next block
+            if end_current_block == end { break; }
+            start_block += 1;
+            start = end_current_block;
+        }
+        read_size
+    }
+    /// File size must be adjusted before.
+    pub fn write_at(
+        &mut self,
+        offset: usize,
+        buf: &[u8],
+        block_device: &Arc<dyn BlockDevice>,
+    ) -> usize {
+        let mut start = offset;
+        let end = (offset + buf.len()).min(self.size as usize);
+        assert!(start <= end);
+        let mut start_block = start / BLOCK_SZ;
+        let mut write_size = 0usize;
+        loop {
+            // calculate end of current block
+            let mut end_current_block = (start / BLOCK_SZ + 1) * BLOCK_SZ;
+            end_current_block = end_current_block.min(end);
+            // write and update write size
+            let block_write_size = end_current_block - start;
+            Dirty::<DataBlock>::new(
+                self.get_block_id(start_block as u32, block_device) as usize,
+                0,
+                block_device.clone()
+            ).modify(|data_block| {
+                let src = &buf[write_size..write_size + block_write_size];
+                let dst = &mut data_block[start % BLOCK_SZ..start % BLOCK_SZ + block_write_size];
+                dst.copy_from_slice(src);
+            });
+            write_size += block_write_size;
+            // move to next block
+            if end_current_block == end { break; }
+            start_block += 1;
+            start = end_current_block;
+        }
+        write_size
+    }
 }
 
 #[repr(C)]
 pub struct DirEntry {
     name: [u8; NAME_LENGTH_LIMIT + 1],
     inode_number: u32,
+}
+
+pub const DIRENT_SZ: usize = 32;
+
+pub type DirentBlock = [DirEntry; BLOCK_SZ / DIRENT_SZ];
+pub type DirentBytes = [u8; DIRENT_SZ];
+
+impl DirEntry {
+    pub fn new(name: &str, inode_number: u32) -> Self {
+        let mut bytes = [0u8; NAME_LENGTH_LIMIT + 1];
+        &mut bytes[..name.len()].copy_from_slice(name.as_bytes());
+        Self {
+            name: bytes,
+            inode_number,
+        }
+    }
+    pub fn into_bytes(&self) -> &DirentBytes {
+        unsafe {
+            &*(self as *const Self as usize as *const DirentBytes)
+        }
+    }
+    pub fn from_bytes(bytes: &DirentBytes) -> &Self {
+        unsafe { &*(bytes.as_ptr() as usize as *const Self) }
+    }
+    pub fn from_bytes_mut(bytes: &mut DirentBytes) -> &mut Self {
+        unsafe {
+            &mut *(bytes.as_mut_ptr() as usize as *mut Self)
+        }
+    }
+    pub fn name(&self) -> &str {
+        let len = (0usize..).find(|i| self.name[*i] == 0).unwrap();
+        core::str::from_utf8(&self.name[..len]).unwrap()
+    }
 }

easy-fs/src/lib.rs

@@ -10,6 +10,7 @@ mod vfs;
 pub const BLOCK_SZ: usize = 512;
 pub use block_dev::BlockDevice;
 pub use efs::EasyFileSystem;
+pub use vfs::Inode;
 use layout::*;
 use dirty::Dirty;
 use bitmap::Bitmap;

easy-fs/src/vfs.rs

@@ -1,3 +1,156 @@
-pub struct Inode {
+use super::{
+    BlockDevice,
+    Dirty,
+    DiskInode,
+    DiskInodeType,
+    DirEntry,
+    DirentBytes,
+    EasyFileSystem,
+    BLOCK_SZ,
+    DIRENT_SZ,
+};
+use alloc::sync::Arc;
+use alloc::string::String;
+use alloc::vec::Vec;
+use crate::layout::DiskInodeType::Directory;
+use spin::{Mutex, MutexGuard};
 
-}
+pub struct Inode {
+    inode_id: u32,
+    fs: Arc<Mutex<EasyFileSystem>>,
+    block_device: Arc<dyn BlockDevice>,
+}
+
+impl Inode {
+    pub fn new(
+        inode_id: u32,
+        fs: Arc<Mutex<EasyFileSystem>>,
+        block_device: Arc<dyn BlockDevice>,
+    ) -> Self {
+        Self {
+            inode_id,
+            fs,
+            block_device,
+        }
+    }
+    fn get_disk_inode(&self) -> Dirty<DiskInode> {
+        self.fs.lock().get_disk_inode(self.inode_id)
+    }
+
+    fn find_inode_id(&self, name: &str) -> Option<u32> {
+        let inode = self.get_disk_inode();
+        // assert it is a directory
+        assert!(inode.read(|inode| inode.is_dir()));
+        let file_count = inode.read(|inode| {
+            inode.size as usize
+        }) / DIRENT_SZ;
+        let mut dirent_space: DirentBytes = Default::default();
+        for i in 0..file_count {
+            assert_eq!(
+                inode.read(|inode| {
+                    inode.read_at(
+                        DIRENT_SZ * i,
+                        &mut dirent_space,
+                        &self.block_device,
+                    )
+                }),
+                DIRENT_SZ,
+            );
+            if DirEntry::from_bytes(&dirent_space).name() == name {
+                return Some(i as u32);
+            }
+        }
+        None
+    }
+
+    fn increase_size(&self, new_size: u32, fs: &mut MutexGuard<EasyFileSystem>) {
+        let mut inode = fs.get_disk_inode(self.inode_id);
+        let blocks_needed = inode.read(|inode| {
+            inode.blocks_num_needed(new_size)
+        });
+        println!("blocks_num_needed = {}", blocks_needed);
+        let mut v: Vec<u32> = Vec::new();
+        for _ in 0..blocks_needed {
+            v.push(fs.alloc_data());
+        }
+        inode.modify(|inode| {
+            inode.increase_size(new_size, v, &self.block_device);
+        });
+    }
+
+    pub fn create(&mut self, name: &str) -> Option<Arc<Inode>> {
+        println!("creating name {}", name);
+        let mut inode = self.get_disk_inode();
+        // assert it is a directory
+        assert!(inode.read(|inode| inode.is_dir()));
+        // has the file been created?
+        if let Some(_) = self.find_inode_id(name) {
+            return None;
+        }
+        println!("stop1");
+
+        // create a new file
+        // alloc a inode with an indirect block
+        let mut fs = self.fs.lock();
+        let new_inode_id = fs.alloc_inode();
+        let indirect1 = fs.alloc_data();
+        println!("creating new file, new_inode_id={}, indirect={}", new_inode_id, indirect1);
+        // initialize inode
+        fs.get_disk_inode(new_inode_id).modify(|inode| {
+            inode.initialize(
+                DiskInodeType::File,
+                indirect1,
+            )
+        });
+
+        // append file in the dirent
+        let file_count =
+            inode.read(|inode| inode.size as usize) / DIRENT_SZ;
+        let new_size = (file_count + 1) * DIRENT_SZ;
+        println!("expected new_size={}", new_size);
+        // increase size
+        self.increase_size(new_size as u32, &mut fs);
+        // write dirent
+        let dirent = DirEntry::new(name, new_inode_id);
+        inode.modify(|inode| {
+            inode.write_at(
+                file_count * DIRENT_SZ,
+                dirent.into_bytes(),
+                &self.block_device,
+            );
+        });
+
+        // return inode
+        Some(Arc::new(Self::new(
+            new_inode_id,
+            self.fs.clone(),
+            self.block_device.clone(),
+        )))
+    }
+
+    pub fn ls(&self) -> Vec<String> {
+        println!("into ls!");
+        let fs = self.fs.lock();
+        let inode = fs.get_disk_inode(self.inode_id);
+        let file_count = inode.read(|inode| {
+            (inode.size as usize) / DIRENT_SZ
+        });
+        println!("file_count = {}", file_count);
+        let mut v: Vec<String> = Vec::new();
+        for i in 0..file_count {
+            let mut dirent_bytes: DirentBytes = Default::default();
+            assert_eq!(
+                inode.read(|inode| {
+                    inode.read_at(
+                        i * DIRENT_SZ,
+                        &mut dirent_bytes,
+                        &self.block_device,
+                    )
+                }),
+                DIRENT_SZ,
+            );
+            v.push(String::from(DirEntry::from_bytes(&dirent_bytes).name()));
+        }
+        v
+    }
+}