From: Avi Kivity <avi@scylladb.com>
To: Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc: linux-kernel <linux-kernel@vger.kernel.org>, linux-aio@kvack.org
Subject: Re: Spurious EIO on AIO+DIO+RWF_NOWAIT
Date: Mon, 10 Dec 2018 14:49:44 +0200 [thread overview]
Message-ID: <53c17661-4914-5266-2034-9fc447e59383@scylladb.com> (raw)
In-Reply-To: <20181210124823.iw4mxmdqpsdfeap4@merlin>
On 10/12/2018 14.48, Goldwyn Rodrigues wrote:
> On 13:19 09/12, Avi Kivity wrote:
>> 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;
>> else
>> 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?
>>
> I don't think REQ_NOWAIT is dropped. I am assuming bio->bi_status error
> is set differently. Is the blk queue being stopped?
Not that I know of.
> Is it possible to
> instrument the kernel in your testcase?
>
I'm happy to apply patches, or run systemtap (or similar) scripts.
next prev parent reply other threads:[~2018-12-10 12:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-09 11:19 Spurious EIO on AIO+DIO+RWF_NOWAIT Avi Kivity
2018-12-10 12:48 ` Goldwyn Rodrigues
2018-12-10 12:49 ` Avi Kivity [this message]
2018-12-12 12:05 ` Avi Kivity
2018-12-12 14:41 ` Goldwyn Rodrigues
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