+int block_write_begin(struct file *, struct address_space *,
+ loff_t, unsigned, unsigned,
+ struct page **, void **, get_block_t*);
+int block_write_end(struct file *, struct address_space *,
+ loff_t, unsigned, unsigned,
+ struct page *, void *);
+int generic_write_end(struct file *, struct address_space *,
+ loff_t, unsigned, unsigned,
+ struct page *, void *);
+void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);