增加注释

Author: kaleidoscope416

kernel/src/filesystem/vfs/file.rs

@@ -408,8 +408,7 @@ impl File {
     #[inline]
     pub fn readable(&self) -> Result<(), SystemError> {
         let mode = *self.mode.read();
-
-        // 检查是否是O_PATH文件描述符
+        // 暂时认为只要不是write only, 就可读
         if mode == FileMode::O_WRONLY || mode.contains(FileMode::O_PATH) {
             return Err(SystemError::EBADF);
         }