From 0a9fcf5f8a8aa61559f545f32ddca0d3db082380 Mon Sep 17 00:00:00 2001
From: Thomas Schoebel-Theuer <tst@1und1.de>
Date: Wed, 1 Mar 2017 08:49:10 +0100
Subject: [PATCH] copy: speed up the speedup

---
 kernel/mars_copy.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/mars_copy.c b/kernel/mars_copy.c
index cade8cf3..6c10a094 100644
--- a/kernel/mars_copy.c
+++ b/kernel/mars_copy.c
@@ -223,7 +223,11 @@ void copy_endio(struct generic_callback *cb)
 	brick = mref_a->brick;
 	CHECK_PTR(brick, err);
 
-	brick->check_hint = mref->ref_pos;
+	/* This is racy, but affects only a _hint_ for
+	 * performance optimization.
+	 */
+	if (!brick->check_hint || mref->ref_pos < brick->check_hint)
+		brick->check_hint = mref->ref_pos;
 
 	queue = mref_a->queue;
 	index = GET_INDEX(mref->ref_pos);