Commit 7de55b7d authored by Johannes Thumshirn's avatar Johannes Thumshirn Committed by Jens Axboe
Browse files

block: support zone append bvecs 



Christoph reported that we'll likely trigger the WARN_ON_ONCE() checking
that we're not submitting a bvec with REQ_OP_ZONE_APPEND in
bio_iov_iter_get_pages() some time ago using zoned btrfs, but I couldn't
reproduce it back then.

Now Naohiro was able to trigger the bug as well with xfstests generic/095
on a zoned btrfs.

There is nothing that prevents bvec submissions via REQ_OP_ZONE_APPEND if
the hardware's zone append limit is met.

Reported-by: default avatarNaohiro Aota <naohiro.aota@wdc.com>
Reported-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/10bd414d9326c90cd69029077db63b363854eee5.1616600835.git.johannes.thumshirn@wdc.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent a958937f

block/bio.c

+18 −3
Original line number Diff line number Diff line
@@ -949,7 +949,7 @@ void bio_release_pages(struct bio *bio, bool mark_dirty) 
}

EXPORT_SYMBOL_GPL(bio_release_pages);



static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)

static void __bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)

{

	WARN_ON_ONCE(bio->bi_max_vecs);
@@ -959,11 +959,26 @@ static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter) 
	bio->bi_iter.bi_size = iter->count;

	bio_set_flag(bio, BIO_NO_PAGE_REF);

	bio_set_flag(bio, BIO_CLONED);

}



static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)

{

	__bio_iov_bvec_set(bio, iter);

	iov_iter_advance(iter, iter->count);

	return 0;

}



static int bio_iov_bvec_set_append(struct bio *bio, struct iov_iter *iter)

{

	struct request_queue *q = bio->bi_bdev->bd_disk->queue;

	struct iov_iter i = *iter;



	iov_iter_truncate(&i, queue_max_zone_append_sectors(q) << 9);

	__bio_iov_bvec_set(bio, &i);

	iov_iter_advance(iter, i.count);

	return 0;

}



#define PAGE_PTRS_PER_BVEC     (sizeof(struct bio_vec) / sizeof(struct page *))



/**
@@ -1094,8 +1109,8 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) 
	int ret = 0;



	if (iov_iter_is_bvec(iter)) {

		if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))

			return -EINVAL;

		if (bio_op(bio) == REQ_OP_ZONE_APPEND)

			return bio_iov_bvec_set_append(bio, iter);

		return bio_iov_bvec_set(bio, iter);

	}