From 0b43d4f8c76d4ee4a05090b3d1db70d61e1c461c Mon Sep 17 00:00:00 2001
From: Ondrej Kozina <okozina@redhat.com>
Date: Tue, 15 Mar 2016 17:04:03 +0100
Subject: [PATCH] rule out race while (u)mounting lvm snapshot

---
 snapper/Lvm.cc | 4 ++++
 snapper/Lvm.h  | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/snapper/Lvm.cc b/snapper/Lvm.cc
index 766dee4..0fb9036 100644
--- a/snapper/Lvm.cc
+++ b/snapper/Lvm.cc
@@ -251,6 +251,8 @@ namespace snapper
     void
     Lvm::mountSnapshot(unsigned int num) const
     {
+	boost::unique_lock<boost::mutex> lock(mount_mutex);
+
 	if (isSnapshotMounted(num))
 	    return;
 
@@ -273,6 +275,8 @@ namespace snapper
     void
     Lvm::umountSnapshot(unsigned int num) const
     {
+	boost::unique_lock<boost::mutex> lock(mount_mutex);
+
 	if (isSnapshotMounted(num))
 	{
 	    SDir info_dir = openInfoDir(num);
diff --git a/snapper/Lvm.h b/snapper/Lvm.h
index 87193ad..be86731 100644
--- a/snapper/Lvm.h
+++ b/snapper/Lvm.h
@@ -24,6 +24,7 @@
 #define SNAPPER_LVM_H
 
 #include <boost/noncopyable.hpp>
+#include <boost/thread/mutex.hpp>
 
 #include "snapper/Filesystem.h"
 
@@ -108,6 +109,8 @@ namespace snapper
 
     private:
 
+	mutable boost::mutex mount_mutex;
+
 	const string mount_type;
 	const LvmCapabilities* caps;
 	LvmCache* cache;
-- 
2.5.5