From 811b30d11604d4bec8c95a13bb22d6b10203cef3 Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Wed, 15 Jul 2020 15:05:44 +0100
Subject: [PATCH] sync: fix deadlock with --track-renames-strategy modtime -
 fixes #4427

Before this change we could exit the popRenameMap function with the
lock held.

This fixes the problem by defer-ring the unlock.

See: https://forum.rclone.org/t/track-renames-strategy-modtime-doesnt-work/16992
---
 fs/sync/sync.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/sync/sync.go b/fs/sync/sync.go
index b915b7d26..4a3c2b01a 100644
--- a/fs/sync/sync.go
+++ b/fs/sync/sync.go
@@ -658,6 +658,7 @@ func (s *syncCopyMove) pushRenameMap(hash string, obj fs.Object) {
 // renameMap or returns nil if not found.
 func (s *syncCopyMove) popRenameMap(hash string, src fs.Object) (dst fs.Object) {
 	s.renameMapMu.Lock()
+	defer s.renameMapMu.Unlock()
 	dsts, ok := s.renameMap[hash]
 	if ok && len(dsts) > 0 {
 		// Element to remove
@@ -690,7 +691,6 @@ func (s *syncCopyMove) popRenameMap(hash string, src fs.Object) (dst fs.Object)
 			delete(s.renameMap, hash)
 		}
 	}
-	s.renameMapMu.Unlock()
 	return dst
 }