xfs: remove xfs_cancel_ioend

xfs: remove xfs_cancel_ioend

We currently have code to cancel ioends being built because we
change bufferhead state as we build the ioend. On error, this needs
to be unwound and so we have cancelling code that walks the buffers
on the ioend chain and undoes these state changes.

However, the IO submission path already handles state changes for
buffers when a submission error occurs, so we don't really need a
separate cancel function to do this - we can simply submit the
ioend chain with the specific error and it will be cancelled rather
than submitted.

Hence we can remove the explicit cancel code and just rely on
submission to deal with the error correctly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
(cherry picked from commit 150d5be09ce49a9bed6feb7b7dc4e5ae188778ec)

Orabug: 28193043

Signed-off-by: Shan Hai <shan.hai@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>