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From: Avi Kivity <>
To: linux-kernel <>,, Goldwyn Rodrigues <>
Subject: Spurious EIO on AIO+DIO+RWF_NOWAIT
Date: Sun, 9 Dec 2018 13:19:51 +0200	[thread overview]
Message-ID: <> (raw)

I have an application that receives spurious EIO when running with 
RWF_NOWAIT enabled. Removing RWF_NOWAIT causes those EIOs to disappear. 
The application uses AIO+DIO, and errors were seen on both xfs and ext4.

I suspect the following code:

  * Process one completed BIO.  No locks are held.
static blk_status_t dio_bio_complete(struct dio *dio, struct bio *bio)
         struct bio_vec *bvec;
         unsigned i;
         blk_status_t err = bio->bi_status;

         if (err) {
                 if (err == BLK_STS_AGAIN && (bio->bi_opf & REQ_NOWAIT))
                         dio->io_error = -EAGAIN;
                         dio->io_error = -EIO;

Could it be that REQ_NOWAIT was dropped from bio->bi_opf? or that 
bio->bi_status got changed along the way?

Reducing the test case may be a lot of work, but I can package a binary 
using docker if a reproducer is needed. Seen on 4.18.19 and 4.19.something.

             reply	other threads:[~2018-12-09 11:19 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-09 11:19 Avi Kivity [this message]
2018-12-10 12:48 ` Spurious EIO on AIO+DIO+RWF_NOWAIT Goldwyn Rodrigues
2018-12-10 12:49   ` Avi Kivity
2018-12-12 12:05   ` Avi Kivity
2018-12-12 14:41     ` Goldwyn Rodrigues

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