linux-kernel - Re: [RFC] iomap: fix race between readahead and direct write

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Message-ID: <fefbacb4-4ad9-df70-a5ab-58df4471800c@huawei.com>
Date:   Sun, 19 Jan 2020 09:25:16 +0800
From:   "yukuai (C)" <yukuai3@...wei.com>
To:     "Darrick J. Wong" <darrick.wong@...cle.com>,
        Jan Kara <jack@...e.cz>
CC:     <hch@...radead.org>, <linux-xfs@...r.kernel.org>,
        <linux-fsdevel@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <houtao1@...wei.com>, <zhengbin13@...wei.com>,
        <yi.zhang@...wei.com>
Subject: Re: [RFC] iomap: fix race between readahead and direct write



On 2020/1/18 0:24, Darrick J. Wong wrote:
> Does the problem go away if you apply[1]?  If I understand the race
> correctly, marking the extents unwritten and leaving them that way until
> after we've written the disk should eliminate the exposure vector...?:)

Thank you for your response.

The patch [1] fixed the stale data exposure problem which was tested by
generic/042. I'm afarid it's completely a diffrent case for generic/418.

In generic/418, direct write wrote some data to disk successfully, while
buffer read left the correspond page uptodate with 0 content in
pagecache.

Thanks!
Yu Kuai