Add info() for vfs::FileSystem. Add fs() for vfs::INode.

src/sfs.rs

@@ -306,6 +306,9 @@ impl vfs::INode for INode {
                 String::from(entry.name.as_ref())
             }).collect())
     }
+    fn fs(&self) -> Weak<vfs::FileSystem> {
+        self.fs.clone()
+    }
 }
 
 impl Drop for INode {
@@ -519,6 +522,13 @@ impl vfs::FileSystem for SimpleFileSystem {
     fn root_inode(&self) -> Ptr<vfs::INode> {
         self.get_inode(BLKN_ROOT)
     }
+
+    fn info(&self) -> &'static vfs::FsInfo {
+        static INFO: vfs::FsInfo = vfs::FsInfo {
+            max_file_size: MAX_FILE_SIZE,
+        };
+        &INFO
+    }
 }
 
 impl Drop for SimpleFileSystem {

src/vfs.rs

@@ -21,12 +21,12 @@ pub trait INode: Debug {
     fn sync(&mut self) -> Result<()>;
 //    fn name_file(&mut self) -> Result<()>;
 //    fn reclaim(&mut self) -> Result<()>;
-//    fn try_seek(&mut self, offset: u64) -> Result<()>;
     fn resize(&mut self, len: usize) -> Result<()>;
     fn create(&mut self, name: &'static str, type_: FileType) -> Result<INodePtr>;
     fn lookup(&self, path: &'static str) -> Result<INodePtr>;
     fn list(&self) -> Result<Vec<String>>;
 //    fn io_ctrl(&mut self, op: u32, data: &[u8]) -> Result<()>;
+    fn fs(&self) -> Weak<FileSystem>;
 }
 
 #[derive(Debug, Eq, PartialEq)]
@@ -42,12 +42,18 @@ pub enum FileType {
     File, Dir,
 }
 
+#[derive(Debug)]
+pub struct FsInfo {
+    pub max_file_size: usize,
+}
+
 pub type Result<T> = core::result::Result<T, ()>;
 
 /// Abstract filesystem
 pub trait FileSystem {
     fn sync(&self) -> Result<()>;
     fn root_inode(&self) -> INodePtr;
+    fn info(&self) -> &'static FsInfo;
 //    fn unmount(&self) -> Result<()>;
 //    fn cleanup(&self);
 }