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Date:   Mon, 12 Jun 2023 11:25:43 +0200
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Ilya Dryomov <idryomov@gmail.com>
Cc:     stable@vger.kernel.org,
        Dongsheng Yang <dongsheng.yang@easystack.cn>
Subject: Re: [PATCH for 5.4] rbd: get snapshot context after exclusive lock
 is ensured to be held
Message-ID: <2023061228-dab-doorbell-c1ed@gregkh>
References: <20230611184127.29830-1-idryomov@gmail.com>
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On Sun, Jun 11, 2023 at 08:41:27PM +0200, Ilya Dryomov wrote:
> Move capturing the snapshot context into the image request state
> machine, after exclusive lock is ensured to be held for the duration of
> dealing with the image request.  This is needed to ensure correctness
> of fast-diff states (OBJECT_EXISTS vs OBJECT_EXISTS_CLEAN) and object
> deltas computed based off of them.  Otherwise the object map that is
> forked for the snapshot isn't guaranteed to accurately reflect the
> contents of the snapshot when the snapshot is taken under I/O.  This
> breaks differential backup and snapshot-based mirroring use cases with
> fast-diff enabled: since some object deltas may be incomplete, the
> destination image may get corrupted.
> 
> Cc: stable@vger.kernel.org
> Link: https://tracker.ceph.com/issues/61472
> Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
> Reviewed-by: Dongsheng Yang <dongsheng.yang@easystack.cn>
> [idryomov@gmail.com: backport to 5.4: no rbd_img_capture_header(),
>  img_request not embedded in blk-mq pdu]
> ---
>  drivers/block/rbd.c | 41 ++++++++++++++++++++++++-----------------
>  1 file changed, 24 insertions(+), 17 deletions(-)

What is the commit id in Linus's tree of this change?

thanks,

greg k-h