block,fs: use REQ_* flags directly

Remove the WRITE_* and READ_SYNC wrappers, and just use the flags
directly.  Where applicable this also drops usage of the
bio_set_op_attrs wrapper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index c95d369..12eeae6 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -189,7 +189,7 @@ static int nilfs_sync_super(struct super_block *sb, int flag)
 	set_buffer_dirty(nilfs->ns_sbh[0]);
 	if (nilfs_test_opt(nilfs, BARRIER)) {
 		err = __sync_dirty_buffer(nilfs->ns_sbh[0],
-					  WRITE_SYNC | WRITE_FLUSH_FUA);
+					  REQ_SYNC | REQ_PREFLUSH | REQ_FUA);
 	} else {
 		err = sync_dirty_buffer(nilfs->ns_sbh[0]);
 	}