Commit fd9f4e62 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: assign bi_bdev for cloned bios in blk_rq_prep_clone 



bio_clone_fast() sets the cloned bio to have the same ->bi_bdev as the
source bio. This means that when request-based dm called setup_clone(),
the cloned bio had its ->bi_bdev pointing to the dm device. After Commit
0b6e522c ("blk-mq: use ->bi_bdev for I/O accounting")
__blk_account_io_start() started using the request's ->bio->bi_bdev for
I/O accounting, if it was set. This caused IO going to the underlying
devices to use the dm device for their I/O accounting.

Set up the proper ->bi_bdev in blk_rq_prep_clone based on the whole
device bdev for the queue the request is cloned onto.

Fixes: 0b6e522c ("blk-mq: use ->bi_bdev for I/O accounting")
Reported-by: default avatarBenjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
[hch: the commit message is mostly from a different patch from Benjamin]
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarBenjamin Marzinski <bmarzins@redhat.com>
Link: https://lore.kernel.org/r/20220118070444.1241739-1-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 850fd2ab

block/blk-mq.c

+1 −0
Original line number Diff line number Diff line
@@ -2976,6 +2976,7 @@ int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 
		bio = bio_clone_fast(bio_src, gfp_mask, bs);

		if (!bio)

			goto free_and_out;

		bio->bi_bdev = rq->q->disk->part0;



		if (bio_ctr && bio_ctr(bio, bio_src, data))

			goto free_and_out;