Improve debugging and image creation

src/filesystem.rs

@@ -1,22 +1,33 @@
 use alloc::boxed::Box;
 
-use super::{Disk, Header, Node};
+use super::{Disk, Extent, Header, Node};
 
 /// A file system
 pub struct FileSystem<E> {
     pub disk: Box<Disk<E>>,
-    pub header: Header,
+    pub header: (u64, Header),
+    pub root: (u64, Node),
+    pub free: (u64, Node)
 }
 
 impl<E> FileSystem<E> {
     /// Open a file system on a disk
     pub fn open(mut disk: Box<Disk<E>>) -> Result<Option<Self>, E> {
-        let mut header = Header::default();
-        try!(disk.read_at(1, &mut header));
-        if header.valid() {
+        let mut header = (1, Header::default());
+        try!(disk.read_at(header.0, &mut header.1));
+
+        if header.1.valid() {
+            let mut root = (header.1.root, Node::default());
+            try!(disk.read_at(root.0, &mut root.1));
+
+            let mut free = (header.1.free, Node::default());
+            try!(disk.read_at(free.0, &mut free.1));
+
             Ok(Some(FileSystem {
                 disk: disk,
                 header: header,
+                root: root,
+                free: free
             }))
         }else{
             Ok(None)
@@ -25,11 +36,25 @@ impl<E> FileSystem<E> {
 
     /// Create a file system on a disk
     pub fn create(mut disk: Box<Disk<E>>) -> Result<Self, E> {
-        let header = Header::new();
-        try!(disk.write_at(1, &header));
+        let size = try!(disk.size());
+
+        assert!(size > 4);
+
+        let mut free = (3, Node::new("free", Node::MODE_DIR));
+        free.1.extents[0] = Extent::new(4, (size - 4 * 512));
+        try!(disk.write_at(free.0, &free.1));
+
+        let root = (2, Node::new("root", Node::MODE_DIR));
+        try!(disk.write_at(root.0, &root.1));
+
+        let header = (1, Header::new(size, root.0, free.0));
+        try!(disk.write_at(header.0, &header.1));
+
         Ok(FileSystem {
             disk: disk,
             header: header,
+            root: root,
+            free: free
         })
     }