From 36f93649efbd2a3bd7954d8c6f2758507229bda9 Mon Sep 17 00:00:00 2001
From: vyzo <vyzo@hackzen.org>
Date: Sun, 4 Jul 2021 10:10:37 +0300
Subject: [PATCH] fix panic from concurrent map writes in txnRefs

---
 blockstore/splitstore/splitstore.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/blockstore/splitstore/splitstore.go b/blockstore/splitstore/splitstore.go
index 669277abe..ced493ed9 100644
--- a/blockstore/splitstore/splitstore.go
+++ b/blockstore/splitstore/splitstore.go
@@ -145,11 +145,12 @@ type SplitStore struct {
 
 	// protection for concurrent read/writes during compaction
 	txnLk      sync.RWMutex
+	txnActive  bool
 	txnEnv     MarkSetEnv
 	txnProtect MarkSet
 	txnMarkSet MarkSet
+	txnRefsMx  sync.Mutex
 	txnRefs    map[cid.Cid]struct{}
-	txnActive  bool
 }
 
 var _ bstore.Blockstore = (*SplitStore)(nil)
@@ -594,7 +595,9 @@ func (s *SplitStore) trackTxnRef(c cid.Cid, recursive bool) error {
 
 	if s.txnRefs != nil {
 		// we haven't finished marking yet, so track the reference
+		s.txnRefsMx.Lock()
 		s.txnRefs[c] = struct{}{}
+		s.txnRefsMx.Unlock()
 		return nil
 	}