From e04d63ebd3dd5441690da22c43e29b7bd78861af Mon Sep 17 00:00:00 2001
From: rjl493456442 <garyrong0905@gmail.com>
Date: Fri, 13 Jan 2023 18:55:50 +0800
Subject: [PATCH] core/rawdb: fsync head data file before closing it (#26490)

This PR fixes an issue which might result in data lost in freezer.

Whenever mutation happens in freezer, all data will be written into head data file
and it will be rotated with a new one in case the size of file reaches the threshold.

Theoretically, the rotated old data file should be fsync'd to prevent data loss.
In freezer.Sync function, we only fsync: (1) index file (2) meta file and (3) head
data file. So this PR forcibly fsync the head data file if mutation happens in the
boundary of data file.
---
 core/rawdb/chain_freezer.go | 4 ++--
 core/rawdb/freezer_table.go | 7 +++++--
 core/rawdb/freezer_test.go  | 2 +-
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/core/rawdb/chain_freezer.go b/core/rawdb/chain_freezer.go
index 212ec73ed..4348fb5d7 100644
--- a/core/rawdb/chain_freezer.go
+++ b/core/rawdb/chain_freezer.go
@@ -86,14 +86,14 @@ func (f *chainFreezer) Close() error {
 // This functionality is deliberately broken off from block importing to avoid
 // incurring additional data shuffling delays on block propagation.
 func (f *chainFreezer) freeze(db ethdb.KeyValueStore) {
-	nfdb := &nofreezedb{KeyValueStore: db}
-
 	var (
 		backoff   bool
 		triggered chan struct{} // Used in tests
+		nfdb      = &nofreezedb{KeyValueStore: db}
 	)
 	timer := time.NewTimer(freezerRecheckInterval)
 	defer timer.Stop()
+
 	for {
 		select {
 		case <-f.quit:
diff --git a/core/rawdb/freezer_table.go b/core/rawdb/freezer_table.go
index 7af937fd8..394bd5761 100644
--- a/core/rawdb/freezer_table.go
+++ b/core/rawdb/freezer_table.go
@@ -852,8 +852,11 @@ func (t *freezerTable) advanceHead() error {
 	if err != nil {
 		return err
 	}
-
-	// Close old file, and reopen in RDONLY mode.
+	// Commit the contents of the old file to stable storage and
+	// tear it down. It will be re-opened in read-only mode.
+	if err := t.head.Sync(); err != nil {
+		return err
+	}
 	t.releaseFile(t.headId)
 	t.openFile(t.headId, openFreezerFileForReadOnly)
 
diff --git a/core/rawdb/freezer_test.go b/core/rawdb/freezer_test.go
index 630911ec8..8deb04a79 100644
--- a/core/rawdb/freezer_test.go
+++ b/core/rawdb/freezer_test.go
@@ -190,7 +190,7 @@ func TestFreezerConcurrentModifyTruncate(t *testing.T) {
 
 	var item = make([]byte, 256)
 
-	for i := 0; i < 1000; i++ {
+	for i := 0; i < 10; i++ {
 		// First reset and write 100 items.
 		if err := f.TruncateHead(0); err != nil {
 			t.Fatal("truncate failed:", err)