Revert "gfs2: Fix use of bio_chain"

commit 469d715 upstream.

This reverts commit 8a157e0.

That commit incorrectly assumed that the bio_chain() arguments were
swapped in gfs2.  However, gfs2 intentionally constructs bio chains so
that the first bio's bi_end_io callback is invoked when all bios in the
chain have completed, unlike bio chains where the last bio's callback is
invoked.

Fixes: 8a157e0 ("gfs2: Fix use of bio_chain")
Cc: stable@vger.kernel.org
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Andreas Gruenbacher

fs/gfs2/lops.c

@@ -487,7 +487,7 @@ static struct bio *gfs2_chain_bio(struct bio *prev, unsigned int nr_iovecs)
 	new = bio_alloc(prev->bi_bdev, nr_iovecs, prev->bi_opf, GFP_NOIO);
 	bio_clone_blkg_association(new, prev);
 	new->bi_iter.bi_sector = bio_end_sector(prev);
-	bio_chain(prev, new);
+	bio_chain(new, prev);
 	submit_bio(prev);
 	return new;
 }