offset = index & ~zisofs_block_page_mask;
blockindex = offset >> zisofs_block_page_shift;
maxpage = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
offset = index & ~zisofs_block_page_mask;
blockindex = offset >> zisofs_block_page_shift;
maxpage = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;