From 3edf5346e4f2ce2fa0c94651a90a8dda169565ee Mon Sep 17 00:00:00 2001 From: Yufen Yu Date: Wed, 31 Mar 2021 07:53:59 -0400 Subject: block: only update parent bi_status when bio fail For multiple split bios, if one of the bio is fail, the whole should return error to application. But we found there is a race between bio_integrity_verify_fn and bio complete, which return io success to application after one of the bio fail. The race as following: split bio(READ) kworker nvme_complete_rq blk_update_request //split error=0 bio_endio bio_integrity_endio queue_work(kintegrityd_wq, &bip->bip_work); bio_integrity_verify_fn bio_endio //split bio __bio_chain_endio if (!parent->bi_status) nvme_irq blk_update_request //parent error=7 req_bio_endio bio->bi_status = 7 //parent bio parent->bi_status = 0 parent->bi_end_io() // return bi_status=0 The bio has been split as two: split and parent. When split bio completed, it depends on kworker to do endio, while bio_integrity_verify_fn have been interrupted by parent bio complete irq handler. Then, parent bio->bi_status which have been set in irq handler will overwrite by kworker. In fact, even without the above race, we also need to conside the concurrency beteen mulitple split bio complete and update the same parent bi_status. Normally, multiple split bios will be issued to the same hctx and complete from the same irq vector. But if we have updated queue map between multiple split bios, these bios may complete on different hw queue and different irq vector. Then the concurrency update parent bi_status may cause the final status error. Suggested-by: Keith Busch Signed-off-by: Yufen Yu Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20210331115359.1125679-1-yuyufen@huawei.com Signed-off-by: Jens Axboe --- block/bio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block') diff --git a/block/bio.c b/block/bio.c index 963d1d406b3a..50e579088aca 100644 --- a/block/bio.c +++ b/block/bio.c @@ -277,7 +277,7 @@ static struct bio *__bio_chain_endio(struct bio *bio) { struct bio *parent = bio->bi_private; - if (!parent->bi_status) + if (bio->bi_status && !parent->bi_status) parent->bi_status = bio->bi_status; bio_put(bio); return parent; -- cgit v1.2.3