A new field was introduced in 74d46992e0d9dee7f1f376de0d56d31614c8a17a,
bi_partno, instead of using bdev->bd_contains and encoding the partition
information in the bi_bdev field.  __bio_clone_fast was changed to copy
the disk information, but not the partition information.  At minimum,
this regressed bcache and caused data corruption.

Signed-off-by: Michael Lyle <redacted>
Fixes: 74d46992e0d9dee7f1f376de0d56d31614c8a17a
Reported-by: Pavel Goran <redacted>
Reported-by: Campbell Steven <redacted>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <redacted>
---
 block/bio.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/block/bio.c b/block/bio.c
index 101c2a9b5481..33fa6b4af312 100644
--- a/block/bio.c
+++ b/block/bio.c

@@ -597,6 +597,7 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
 	 * so we don't set nor calculate new physical/hw segment counts here
 	 */
 	bio->bi_disk = bio_src->bi_disk;
+	bio->bi_partno = bio_src->bi_partno;
 	bio_set_flag(bio, BIO_CLONED);
 	bio->bi_opf = bio_src->bi_opf;
 	bio->bi_write_hint = bio_src->bi_write_hint;