message: rafs/v6: implement is_dir() and more methods
diff: @@ -362,6 +362,11 @@ impl OndiskInodeWrapper {
  }
  }
  }
  +
  + fn mode_format_bits(&self) -> u32 {
  + let i = self.disk_inode();
  + i.i_mode as u32 & libc::S_IFMT
  + }
  }
  // TODO(chge): Still work on this trait implementation. Remove below `allow` attribute.
  @@ -527,17 +532,17 @@ impl RafsInode for OndiskInodeWrapper {
  }
  fn is_dir(&self) -> bool {
  - todo!()
  + self.mode_format_bits() == libc::S_IFDIR
  }
  /// Check whether the inode is a symlink.
  fn is_symlink(&self) -> bool {
  - todo!()
  + self.mode_format_bits() == libc::S_IFLNK
  }
  /// Check whether the inode is a regular file.
  fn is_reg(&self) -> bool {
  - todo!()
  + self.mode_format_bits() == libc::S_IFREG
  }
  /// Check whether the inode is a hardlink.
  