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From: Jens Axboe <axboe@kernel.dk>
To: Damien Le Moal <damien.lemoal@wdc.com>, linux-block@vger.kernel.org
Cc: Masato Suzuki <masato.suzuki@wdc.com>,
	Naohiro Aota <naohiro.aota@wdc.com>
Subject: Re: [PATCH] block: Fix __blkdev_direct_IO()
Date: Thu, 1 Aug 2019 13:51:44 -0600	[thread overview]
Message-ID: <19115dcc-8a4b-8bb7-f8db-e2474196a5d0@kernel.dk> (raw)
In-Reply-To: <20190801102151.7846-1-damien.lemoal@wdc.com>

On 8/1/19 4:21 AM, Damien Le Moal wrote:
> The recent fix to properly handle IOCB_NOWAIT for async O_DIRECT IO
> (patch 6a43074e2f46) introduced two problems with BIO fragment handling
> for direct IOs:
> 1) The dio size processed is claculated by incrementing the ret variable
> by the size of the bio fragment issued for the dio. However, this size
> is obtained directly from bio->bi_iter.bi_size AFTER the bio submission
> which may result in referencing the bi_size value after the bio
> completed, resulting in an incorrect value use.
> 2) The ret variable is not incremented by the size of the last bio
> fragment issued for the bio, leading to an invalid IO size being
> returned to the user.
> 
> Fix both problem by using dio->size (which is incremented before the bio
> submission) to update the value of ret after bio submissions, including
> for the last bio fragment issued.

Thanks, applied. Do you have a test case? I ran this through the usual
xfstests and block bits, but didn't catch anything.

-- 
Jens Axboe


  reply	other threads:[~2019-08-01 19:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-01 10:21 [PATCH] block: Fix __blkdev_direct_IO() Damien Le Moal
2019-08-01 19:51 ` Jens Axboe [this message]
2019-08-02  1:05   ` Damien Le Moal
2019-08-02  3:57     ` Jens Axboe
2019-08-02  4:11       ` Damien Le Moal
2019-08-05 17:11 ` Bart Van Assche
2019-08-06 19:53   ` Jens Axboe
2019-08-09 13:01     ` Damien Le Moal
2019-08-09 15:52       ` Jens Axboe

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