From fd9f4e62a39f09a7c014d7415c2b9d1390aa0504 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 18 Jan 2022 08:04:44 +0100 Subject: [PATCH] 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 0b6e522cdc4a ("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: 0b6e522cdc4a ("blk-mq: use ->bi_bdev for I/O accounting") Reported-by: Benjamin Marzinski Signed-off-by: Christoph Hellwig [hch: the commit message is mostly from a different patch from Benjamin] Reviewed-by: Ming Lei Reviewed-by: Benjamin Marzinski Link: https://lore.kernel.org/r/20220118070444.1241739-1-hch@lst.de Signed-off-by: Jens Axboe --- block/blk-mq.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index a6d4780580fc..b5e35e63adad 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -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;