From 036566629ac327deaa66a296387901b56b6fb325 Mon Sep 17 00:00:00 2001
From: chrislu <chris.lu@gmail.com>
Date: Mon, 1 Aug 2022 00:06:18 -0700
Subject: [PATCH] filer.sync: fix synchronization logic in active-active mode

fix https://github.com/seaweedfs/seaweedfs/issues/3328
---
 weed/filer/filechunks.go       |  5 ++++-
 weed/filer/filechunks2_test.go | 39 ++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/weed/filer/filechunks.go b/weed/filer/filechunks.go
index 3b99e0785..00f4c2921 100644
--- a/weed/filer/filechunks.go
+++ b/weed/filer/filechunks.go
@@ -114,9 +114,12 @@ func DoMinusChunksBySourceFileId(as, bs []*filer_pb.FileChunk) (delta []*filer_p
 	fileIds := make(map[string]bool)
 	for _, interval := range bs {
 		fileIds[interval.GetFileIdString()] = true
+		fileIds[interval.GetSourceFileId()] = true
 	}
 	for _, chunk := range as {
-		if _, found := fileIds[chunk.GetSourceFileId()]; !found {
+		_, sourceFileIdFound := fileIds[chunk.GetSourceFileId()]
+		_, fileIdFound := fileIds[chunk.GetFileId()]
+		if !sourceFileIdFound && !fileIdFound {
 			delta = append(delta, chunk)
 		}
 	}
diff --git a/weed/filer/filechunks2_test.go b/weed/filer/filechunks2_test.go
index fe35b4a05..7aa00864b 100644
--- a/weed/filer/filechunks2_test.go
+++ b/weed/filer/filechunks2_test.go
@@ -1,13 +1,52 @@
 package filer
 
 import (
+	"github.com/stretchr/testify/assert"
 	"golang.org/x/exp/slices"
+	"log"
 	"testing"
 
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
 )
 
+func TestDoMinusChunks(t *testing.T) {
+	// https://github.com/seaweedfs/seaweedfs/issues/3328
+
+	// clusterA and clusterB using filer.sync to sync file: hello.txt
+	// clusterA append a new line and then clusterB also append a new line
+	// clusterA append a new line again
+	chunksInA := []*filer_pb.FileChunk{
+		{Offset: 0, Size: 3, FileId: "11", Mtime: 100},
+		{Offset: 3, Size: 3, FileId: "22", SourceFileId: "2", Mtime: 200},
+		{Offset: 6, Size: 3, FileId: "33", Mtime: 300},
+	}
+	chunksInB := []*filer_pb.FileChunk{
+		{Offset: 0, Size: 3, FileId: "1", SourceFileId: "11", Mtime: 100},
+		{Offset: 3, Size: 3, FileId: "2", Mtime: 200},
+		{Offset: 6, Size: 3, FileId: "3", SourceFileId: "33", Mtime: 300},
+	}
+
+	// clusterB using command "echo 'content' > hello.txt" to overwrite file
+	// clusterA will receive two evenNotification, need to empty the whole file content first and add new content
+	// the first one is oldEntry is chunksInB and newEntry is empty fileChunks
+	firstOldEntry := chunksInB
+	var firstNewEntry []*filer_pb.FileChunk
+
+	// clusterA received the first one event, gonna empty the whole chunk, according the code in filer_sink 194
+	// we can get the deleted chunks and newChunks
+	firstDeletedChunks := DoMinusChunks(firstOldEntry, firstNewEntry)
+	log.Println("first deleted chunks:", firstDeletedChunks)
+	//firstNewEntry := DoMinusChunks(firstNewEntry, firstOldEntry)
+
+	// clusterA need to delete all chunks in firstDeletedChunks
+	emptiedChunksInA := DoMinusChunksBySourceFileId(chunksInA, firstDeletedChunks)
+	// chunksInA supposed to be empty by minus the deletedChunks but it just delete the chunk which sync from clusterB
+	log.Println("clusterA synced empty chunks event result:", emptiedChunksInA)
+	// clusterB emptied it's chunks and clusterA must sync the change and empty chunks too
+	assert.Equalf(t, firstNewEntry, emptiedChunksInA, "empty")
+}
+
 func TestCompactFileChunksRealCase(t *testing.T) {
 
 	chunks := []*filer_pb.FileChunk{