/* Use one bit per "chunk" (block set). We do the disk I/O on the bitmap file a page at a time. There's a superblock at the start of the file.  */
static unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
/* Use one bit per "chunk" (block set). We do the disk I/O on the bitmap file a page at a time. There's a superblock at the start of the file.  */
static unsigned long file_page_index(struct bitmap *bitmap, unsigned long chunk)
{
	if (!bitmap->mddev->bitmap_info.external)
		chunk += sizeof(bitmap_super_t) << 3;
	return chunk >> PAGE_BIT_SHIFT;
}