This is disallowed.

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
 block/bio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/block/bio.c b/block/bio.c
index 42cac7c46e55..ac2b11b164af 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1749,6 +1749,10 @@ struct bio *bio_split(struct bio *bio, int sectors,
 	if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))
 		return ERR_PTR(-EINVAL);
 
+	/* atomic writes cannot be split */
+	if (bio->bi_opf & REQ_ATOMIC)
+		return ERR_PTR(-EINVAL);
+
 	split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs);
 	if (!split)
 		return ERR_PTR(-ENOMEM);
-- 
2.31.1

Looks good,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>