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Message-ID: <7a5088a8-b5dc-472d-4f43-29d68e3cde16@squashfs.org.uk>
Date:   Fri, 26 May 2023 18:59:00 +0100
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Subject: Re: [PATCH mm-nonmm-unstable v2 1/2] squashfs: fix page update race
To:     Vincent Whitchurch <vincent.whitchurch@axis.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     hch@lst.de, linux-kernel@vger.kernel.org, kernel@axis.com
References: <20230526-squashfs-cache-fixup-v2-0-6fb7723c3647@axis.com>
 <20230526-squashfs-cache-fixup-v2-1-6fb7723c3647@axis.com>
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From:   Phillip Lougher <phillip@squashfs.org.uk>
In-Reply-To: <20230526-squashfs-cache-fixup-v2-1-6fb7723c3647@axis.com>
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On 26/05/2023 14:57, Vincent Whitchurch wrote:
> We only put the page into the cache after we've read it, so the
> PageUptodate() check should not be necessary.  In fact, it's actively
> harmful since the check could fail (since we used find_get_page() and
> not find_lock_page()) and we could end up submitting a page for I/O
> after it has been read and while it's actively being used, which could
> lead to corruption depending on what the block driver does with it.
>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>


Reviewed-by: Phillip Lougher <phillip@squashfs.org.uk>