[server] CoW: Fix calculating copy speed, don't return delay=0

Returning a calculated delay of 0 tells the caller that we
wrote the modified block, which isn't true, so in effect a
corrupted final image is created where certain modified blocks
are missing.

1 files changed, 11 insertions, 8 deletions

diff --git a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/cow/CowSession.java b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/cow/CowSession.java
index a2814d15..c24f4acb 100644
--- a/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/cow/CowSession.java
+++ b/dozentenmodulserver/src/main/java/org/openslx/bwlp/sat/fileserv/cow/CowSession.java
@@ -50,7 +50,7 @@ public class CowSession {
 
 	private final CowSessionData data;
 
-	private int estimatedSpeedKbs = 0;
+	private long estimatedSpeedKbs = 0;
 
 	/**
 	 * Use for operations on destinationFile.
@@ -336,6 +336,9 @@ public class CowSession {
 			if (estimatedSpeedKbs > 0) {
 				delay = (int) ((missing / 1000) / estimatedSpeedKbs);
 			}
+			if (delay < 1) {
+				delay = 1;
+			}
 			LOGGER.info("Throttling client - Missing: " + Util.formatBytes(missing) + ", Speed: "
 					+ Util.formatBytes(estimatedSpeedKbs * 1000) + "/s, Wait: " + delay);
 			return delay;
@@ -361,7 +364,7 @@ public class CowSession {
 			public void run() {
 				long lastTime = Util.tickCount();
 				long byteCount = 0;
-				int[] history = new int[10];
+				long[] history = new long[10];
 				int historySlot = 0;
 				try {
 					byte[] chunk = new byte[COPY_BLOCK_SIZE];
@@ -386,7 +389,7 @@ public class CowSession {
 							long now = Util.tickCount();
 							long delta = now - lastTime;
 							if (delta > 1000) {
-								history[historySlot++ % history.length] = (int) (byteCount / delta);
+								history[historySlot++ % history.length] = byteCount / delta;
 								byteCount = 0;
 								lastTime = now;
 								updateSpeedEstimate(history);
@@ -410,16 +413,16 @@ public class CowSession {
 				}
 			}
 
-			private void updateSpeedEstimate(int[] values) {
-				int sum = 0;
-				for (int i = 0; i < values.length; ++i) {
+			private void updateSpeedEstimate(long[] history) {
+				long sum = 0;
+				for (int i = 0; i < history.length; ++i) {
 					// Some slots might still be 0 in the beginning, so for the first 10+ seconds
 					// we underestimate. But that shouldn't matter since background upload on the
 					// client only starts 60 seconds in.
-					sum += values[i];
+					sum += history[i];
 				}
 				// This is effectively KB/s, as we divided by milliseconds, not seconds
-				estimatedSpeedKbs = sum;
+				estimatedSpeedKbs = sum / history.length;
 			}
 		};
 		synchronized (varLock) {