xfs: chain bios the right way around in xfs_rw_bdev

We need to chain the earlier bios to the later ones, so that
submit_bio_wait waits on the bio that all the completions are
dispatched to.

Fixes: 6ad5b325 ("xfs: use bios directly to read and write the log recovery buffers")
Reported-by: Dave Chinner <david@fromorbit.com>
Tested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_bio_io.c

@@ -43,7 +43,7 @@ xfs_rw_bdev(
 			bio_copy_dev(bio, prev);
 			bio->bi_iter.bi_sector = bio_end_sector(prev);
 			bio->bi_opf = prev->bi_opf;
-			bio_chain(bio, prev);
+			bio_chain(prev, bio);
 
 			submit_bio(prev);
 		}