bdev_freeze
EXPORT_SYMBOL(bdev_freeze);
r = bdev_freeze(md->disk->part0);
ret = bdev_freeze(sb->s_bdev);
ret = bdev_freeze(sb->s_bdev);
ret = bdev_freeze(sb->s_bdev);
err = bdev_freeze(sb->s_bdev);
if (!bdev_freeze(mp->m_super->s_bdev)) {
int bdev_freeze(struct block_device *bdev);