Re: [PATCH for 5.4] rbd: get snapshot context after exclusive lock is ensured to be held

[Greg KH <gregkh@linuxfoundation.org>]

On Mon, Jun 12, 2023 at 11:32:32AM +0200, Ilya Dryomov wrote:
> On Mon, Jun 12, 2023 at 11:25 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> > 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?
> 
> Hi Greg,
> 
> It's 870611e4877eff1e8413c3fb92a585e45d5291f6.

Great, now queued up, thanks.

greg k-h