if (b)
if (b) { b->bi_destructor = bio_fs_destructor;
struct bio *bio_clone(struct bio *bio, unsigned int __nocast gfp_mask){	struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set);	if (b)		__bio_clone(b, bio);	return b;}