Commit de67c139 authored by Mikulas Patocka's avatar Mikulas Patocka
Browse files

dm: test for REQ_ATOMIC in dm_accept_partial_bio() 



Any bio with REQ_ATOMIC flag set should never be split or partially
completed, so BUG_ON() on this scenario in dm_accept_partial_bio() (whose
intent is to allow partial completions).

Also, we must reject atomic bio to targets that don't support them,
otherwise this BUG could be triggered by stray bios that have the
REQ_ATOMIC set.

Signed-off-by: default avatarJohn Garry <john.g.garry@oracle.com>
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Tested-by: default avatarJohn Garry <john.g.garry@oracle.com>
parent b9dd1f71

drivers/md/dm.c

+7 −2
Original line number Diff line number Diff line
@@ -1321,6 +1321,7 @@ void dm_accept_partial_bio(struct bio *bio, unsigned int n_sectors) 
	BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));

	BUG_ON(bio_sectors > *tio->len_ptr);

	BUG_ON(n_sectors > bio_sectors);

	BUG_ON(bio->bi_opf & REQ_ATOMIC);



	if (static_branch_unlikely(&zoned_enabled) &&

	    unlikely(bdev_is_zoned(bio->bi_bdev))) {
@@ -1735,8 +1736,12 @@ static blk_status_t __split_and_process_bio(struct clone_info *ci) 
	ci->submit_as_polled = !!(ci->bio->bi_opf & REQ_POLLED);



	len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);

	if (ci->bio->bi_opf & REQ_ATOMIC && len != ci->sector_count)

	if (ci->bio->bi_opf & REQ_ATOMIC) {

		if (unlikely(!dm_target_supports_atomic_writes(ti->type)))

			return BLK_STS_IOERR;

		if (unlikely(len != ci->sector_count))

			return BLK_STS_IOERR;

	}



	setup_split_accounting(ci, len);