block: switch sync_dirty_buffer() over to WRITE_SYNC

We should now have the logic in place to handle this properly
without regressing on the write performance, so re-enable
the sync writes.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/buffer.c b/fs/buffer.c
index 43afaa5..6e35762 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3010,7 +3010,7 @@
 	if (test_clear_buffer_dirty(bh)) {
 		get_bh(bh);
 		bh->b_end_io = end_buffer_write_sync;
-		ret = submit_bh(WRITE, bh);
+		ret = submit_bh(WRITE_SYNC, bh);
 		wait_on_buffer(bh);
 		if (buffer_eopnotsupp(bh)) {
 			clear_buffer_eopnotsupp(bh);