+static unsigned long long
+super_1_rdev_size_change(mdk_rdev_t *rdev, sector_t num_sectors)
+{
+ struct mdp_superblock_1 *sb;
+ sector_t max_sectors;
+ if (num_sectors && num_sectors < rdev->mddev->size * 2)
+ return 0; /* component must fit device */
+ if (rdev->sb_start < rdev->data_offset) {
+ /* minor versions 1 and 2; superblock before data */
+ max_sectors = rdev->bdev->bd_inode->i_size >> 9;
+ max_sectors -= rdev->data_offset;
+ if (!num_sectors || num_sectors > max_sectors)
+ num_sectors = max_sectors;
+ } else if (rdev->mddev->bitmap_offset) {
+ /* minor version 0 with bitmap we can't move */
+ return 0;
+ } else {
+ /* minor version 0; superblock after data */
+ sector_t sb_start;
+ sb_start = (rdev->bdev->bd_inode->i_size >> 9) - 8*2;
+ sb_start &= ~(sector_t)(4*2 - 1);
+ max_sectors = rdev->size * 2 + sb_start - rdev->sb_start;
+ if (!num_sectors || num_sectors > max_sectors)
+ num_sectors = max_sectors;
+ rdev->sb_start = sb_start;
+ }
+ sb = (struct mdp_superblock_1 *) page_address(rdev->sb_page);
+ sb->data_size = cpu_to_le64(num_sectors);
+ sb->super_offset = rdev->sb_start;
+ sb->sb_csum = calc_sb_1_csum(sb);
+ md_super_write(rdev->mddev, rdev, rdev->sb_start, rdev->sb_size,
+ rdev->sb_page);
+ md_super_wait(rdev->mddev);
+ return num_sectors / 2; /* kB for sysfs */
+}