Create new SFS from blank disk

src/dirty.rs

@@ -16,6 +16,14 @@ impl<T> Dirty<T> {
         }
     }
 
+    /// Create a new Dirty with dirty set
+    pub fn new_dirty(val: T) -> Dirty<T> {
+        Dirty {
+            value: val,
+            dirty: true,
+        }
+    }
+
     /// Returns true if dirty, false otherwise
     #[allow(dead_code)]
     pub fn dirty(&self) -> bool {

src/sfs.rs

@@ -104,7 +104,7 @@ impl vfs::INode for INode {
         for BlockRange { block, begin, end } in iter {
             if let Some(disk_block_id) = self.disk_block_id(block) {
                 let len = end - begin;
-                fs.borrow_mut().device.read_block(disk_block_id, begin, &mut buf[buf_offset..buf_offset + len]);
+                fs.borrow_mut().device.read_block(disk_block_id, begin, &mut buf[buf_offset..buf_offset + len]).unwrap();
                 buf_offset += len;
             } else {
                 // Failed this time
@@ -126,7 +126,7 @@ impl vfs::INode for INode {
         for BlockRange { block, begin, end } in iter {
             if let Some(disk_block_id) = self.disk_block_id(block) {
                 let len = end - begin;
-                fs.borrow_mut().device.write_block(disk_block_id, begin, &buf[buf_offset..buf_offset + len]);
+                fs.borrow_mut().device.write_block(disk_block_id, begin, &buf[buf_offset..buf_offset + len]).unwrap();
                 buf_offset += len;
             } else {
                 // Failed this time
@@ -192,7 +192,7 @@ pub struct SimpleFileSystem {
     /// on-disk superblock
     super_block: Dirty<SuperBlock>,
     /// blocks in use are mared 0
-    free_map: BitSet,
+    free_map: Dirty<BitSet>,
     /// inode list
     inodes: BTreeMap<INodeId, Ptr<INode>>,
     /// device
@@ -202,23 +202,51 @@ pub struct SimpleFileSystem {
 }
 
 impl SimpleFileSystem {
-    /// Create a new SFS with device
-    pub fn new(mut device: Box<Device>) -> Option<Ptr<Self>> {
+    /// Load SFS from device
+    pub fn open(mut device: Box<Device>) -> Option<Ptr<Self>> {
         let super_block = load_struct::<SuperBlock>(device.as_mut(), BLKN_SUPER);
         if super_block.check() == false {
             return None;
         }
+        let free_map = load_struct::<[u8; BLKSIZE]>(device.as_mut(), BLKN_FREEMAP);
 
-        let mut fs = Rc::new(RefCell::new(SimpleFileSystem {
+        Some(SimpleFileSystem {
             super_block: Dirty::new(super_block),
-            free_map: BitSet::new(),
+            free_map: Dirty::new(BitSet::from_bytes(&free_map)),
             inodes: BTreeMap::<INodeId, Ptr<INode>>::new(),
             device,
             self_ptr: Weak::default(),
-        }));
+        }.wrap())
+    }
+    /// Create a new SFS on blank disk
+    pub fn create(mut device: Box<Device>, space: usize) -> Ptr<Self> {
+        let blocks = (space / BLKSIZE).min(BLKBITS);
+        assert!(blocks >= 16, "space too small");
+
+        let super_block = SuperBlock {
+            magic: MAGIC,
+            blocks: blocks as u32,
+            unused_blocks: blocks as u32 - 3,
+            info: Str32::from_slice(b"simple file system"),
+        };
+        let mut free_map = BitSet::with_capacity(BLKBITS);
+        for i in 3 .. blocks {
+            free_map.insert(i);
+        }
+        SimpleFileSystem {
+            super_block: Dirty::new_dirty(super_block),
+            free_map: Dirty::new_dirty(free_map),
+            inodes: BTreeMap::<INodeId, Ptr<INode>>::new(),
+            device,
+            self_ptr: Weak::default(),
+        }.wrap()
+    }
+    /// Wrap pure SimpleFileSystem with Rc<RefCell<...>>
+    /// Used in constructors
+    fn wrap(self) -> Ptr<Self> {
+        let mut fs = Rc::new(RefCell::new(self));
         fs.borrow_mut().self_ptr = Rc::downgrade(&fs);
-
-        Some(fs)
+        fs
     }
     /// Allocate a block, return block id
     fn alloc_block(&mut self) -> Option<usize> {
@@ -264,13 +292,18 @@ impl vfs::FileSystem for SimpleFileSystem {
         let SimpleFileSystem {
             ref mut super_block,
             ref mut device,
+            ref mut free_map,
             ..
         } = self;
 
         if super_block.dirty() {
-            device.write_at(0, super_block.as_buf());
+            device.write_at(BLKSIZE * BLKN_SUPER, super_block.as_buf()).unwrap();
             super_block.sync();
         }
+        if free_map.dirty() {
+            device.write_at(BLKSIZE * BLKN_FREEMAP, free_map.as_buf()).unwrap();
+            free_map.sync();
+        }
         Ok(())
     }
 
@@ -287,6 +320,14 @@ impl vfs::FileSystem for SimpleFileSystem {
     }
 }
 
+impl Drop for SimpleFileSystem {
+    /// Auto sync when drop
+    fn drop(&mut self) {
+        use vfs::FileSystem;
+        self.sync().expect("failed to sync");
+    }
+}
+
 trait BitsetAlloc {
     fn alloc(&mut self) -> Option<usize>;
 }
@@ -302,6 +343,19 @@ impl BitsetAlloc for BitSet {
     }
 }
 
+impl AsBuf for BitSet {
+    fn as_buf(&self) -> &[u8] {
+        let slice = self.get_ref().storage();
+        unsafe{ slice::from_raw_parts(slice as *const _ as *const u8, slice.len() * 4) }
+    }
+    fn as_buf_mut(&mut self) -> &mut [u8] {
+        let slice = self.get_ref().storage();
+        unsafe{ slice::from_raw_parts_mut(slice as *const _ as *mut u8, slice.len() * 4) }
+    }
+}
+
+impl AsBuf for [u8; BLKSIZE] {}
+
 #[cfg(test)]
 mod test {
     use super::*;

src/structs.rs

@@ -72,6 +72,13 @@ impl Debug for Str32 {
         write!(f, "{}", String::from_utf8_lossy(&self.0[0 .. len]))
     }
 }
+impl Str32 {
+    pub fn from_slice(s: &[u8]) -> Self {
+        let mut ret = [0u8; 32];
+        ret[0..s.len()].copy_from_slice(s);
+        Str32(ret)
+    }
+}
 
 impl SuperBlock {
     pub fn check(&self) -> bool {

src/tests.rs

@@ -1,4 +1,4 @@
-use std::fs::File;
+use std::fs::{File, OpenOptions};
 use std::io::{Read, Write, Seek, SeekFrom};
 use std::boxed::Box;
 use super::sfs::*;
@@ -26,9 +26,9 @@ impl Device for File {
 fn test() {
     let file = File::open("sfs.img")
         .expect("failed to open sfs.img");
-    let sfs = SimpleFileSystem::new(Box::new(file))
+    let sfs = SimpleFileSystem::open(Box::new(file))
         .expect("failed to create SFS");
-    let mut root = sfs.borrow_mut().root_inode();
+    let root = sfs.borrow_mut().root_inode();
     println!("{:?}", root);
 
     use super::structs::{DiskEntry, AsBuf};
@@ -40,3 +40,13 @@ fn test() {
         println!("{:?}", entry);
     }
 }
+
+#[test]
+fn create() {
+    let file = OpenOptions::new()
+        .read(true).write(true).create(true).open("test.img")
+        .expect("failed to create file");
+    let sfs = SimpleFileSystem::create(Box::new(file), 16 * 4096);
+
+
+}