From: Mikulas Patocka Date: Wed, 5 Nov 2025 15:01:33 +0000 (+0100) Subject: dm: test for REQ_ATOMIC in dm_accept_partial_bio() X-Git-Tag: v6.19-rc1~28^2~13 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=de67c139b3846ece6b8bbb62abf1f010ae85c083;p=thirdparty%2Flinux.git 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: John Garry Signed-off-by: Mikulas Patocka Tested-by: John Garry --- diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 557f3f52edf4..44be646574b7 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -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) - return BLK_STS_IOERR; + 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);