From: Keith Busch <keith.busch@intel.com>
To: Ming Lei <tom.leiming@gmail.com>
Cc: linux-block@vger.kernel.org, Jens Axboe <axboe@fb.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] blk-mq: Return invalid cookie if bio was split
Date: Tue, 27 Sep 2016 14:24:27 -0400 [thread overview]
Message-ID: <20160927182426.GD24200@localhost.localdomain> (raw)
In-Reply-To: <20160927172536.53a1315f@tom-ThinkPad-T450>
On Tue, Sep 27, 2016 at 05:25:36PM +0800, Ming Lei wrote:
> On Mon, 26 Sep 2016 19:00:30 -0400
> Keith Busch <keith.busch@intel.com> wrote:
>
> > The only user of polling requires its original request be completed in
> > its entirety before continuing execution. If the bio needs to be split
> > and chained for any reason, the direct IO path would have waited for just
> > that split portion to complete, leading to potential data corruption if
> > the remaining transfer has not yet completed.
>
> The issue looks a bit tricky because there is no per-bio place for holding
> the cookie, and generic_make_request() only returns the cookie for the
> last bio in the current bio list, so maybe we need the following patch too.
>
> Also seems merge case need to take care of too.
Yah, I think you're right. I'll try to work out a test case that more
readily exposes the problem so I can better verify the fix.
next prev parent reply other threads:[~2016-09-27 18:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-26 23:00 [PATCH] blk-mq: Return invalid cookie if bio was split Keith Busch
2016-09-27 9:25 ` Ming Lei
2016-09-27 18:24 ` Keith Busch [this message]
2016-10-03 22:00 ` Keith Busch
2016-10-05 3:19 ` Ming Lei
2016-10-05 16:51 ` Keith Busch
2016-10-06 16:06 ` Ming Lei
2016-10-06 16:39 ` Keith Busch
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