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authorYufen Yu <yuyufen@huawei.com>2021-03-31 07:53:59 -0400
committerJens Axboe <axboe@kernel.dk>2021-03-31 19:18:04 -0600
commit3edf5346e4f2ce2fa0c94651a90a8dda169565ee (patch)
tree0832502839bb11e70327e3afd42ee3a0d61c3358 /block
parente82fc7855749aa197740a60ef22c492c41ea5d5f (diff)
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) <interrupt entry> nvme_irq blk_update_request //parent error=7 req_bio_endio bio->bi_status = 7 //parent bio <interrupt exit> 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 <kbusch@kernel.org> Signed-off-by: Yufen Yu <yuyufen@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20210331115359.1125679-1-yuyufen@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r--block/bio.c2
1 files changed, 1 insertions, 1 deletions
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;

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