From df559f3042539675f567b225979b957ab749b075 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beat=20K=C3=BCng?= <beat-kueng@gmx.net>
Date: Tue, 6 Nov 2018 13:24:48 +0100
Subject: [PATCH] logger: unlock the mutex for fsync & call fsync only when
 backend is running

- fsync can be a long blocking operation, so we need to make sure the main
  logger thread does not block during this time, when it tries to aquire
  the mutex
- fixes calling fsync on an invalid file descriptor
---
 src/modules/logger/log_writer_file.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/modules/logger/log_writer_file.cpp b/src/modules/logger/log_writer_file.cpp
index 24095a3738..a2c09fbc7f 100644
--- a/src/modules/logger/log_writer_file.cpp
+++ b/src/modules/logger/log_writer_file.cpp
@@ -257,8 +257,10 @@ void LogWriterFile::run()
 						buffer.close_file();
 					}
 
-				} else if (call_fsync) {
+				} else if (call_fsync && buffer._should_run) {
+					pthread_mutex_unlock(&_mtx);
 					buffer.fsync();
+					pthread_mutex_lock(&_mtx);
 
 				} else if (available == 0 && !buffer._should_run) {
 					buffer.close_file();