extern struct file_operations nilfs_dir_operations;
extern struct inode_operations nilfs_file_inode_operations;
extern struct file_operations nilfs_file_operations;
-extern struct address_space_operations nilfs_aops;
+extern const struct address_space_operations nilfs_aops;
extern struct inode_operations nilfs_dir_inode_operations;
extern struct inode_operations nilfs_special_inode_operations;
extern struct inode_operations nilfs_symlink_inode_operations;