diff --git a/Jamfile b/Jamfile
index ed30d2a3a..542897f5c 100755
--- a/Jamfile
+++ b/Jamfile
@@ -4,6 +4,7 @@ import modules ;
 import os ;
 import errors ;
 import feature : feature ;
+#import pch ;
 
 BOOST_ROOT = [ modules.peek : BOOST_ROOT ] ;
 
@@ -157,11 +158,14 @@ project torrent
 
 	;
 
+#cpp-pch pch : include/libtorrent/pch.hpp ;
+
 lib torrent
 	:
 	src/$(SOURCES)
 	zlib/$(ZLIB_SOURCES)
 	$(LIBS)
+#	pch
 	:
 	<dht-support>on:<source>src/$(KADEMLIA_SOURCES)
 	<dht-support>logging:<source>src/$(KADEMLIA_SOURCES)
diff --git a/include/Makefile.am b/include/Makefile.am
index 7b1f4d66a..59b1e26cc 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -23,6 +23,7 @@ libtorrent/peer_connection.hpp \
 libtorrent/bt_peer_connection.hpp \
 libtorrent/web_peer_connection.hpp \
 libtorrent/natpmp.hpp \
+libtorrent/pch.hpp \
 libtorrent/peer_id.hpp \
 libtorrent/peer_info.hpp \
 libtorrent/peer_request.hpp \
diff --git a/include/libtorrent/hasher.hpp b/include/libtorrent/hasher.hpp
index 803b758eb..434dff3bf 100755
--- a/include/libtorrent/hasher.hpp
+++ b/include/libtorrent/hasher.hpp
@@ -38,6 +38,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/peer_id.hpp"
 #include "libtorrent/config.hpp"
+#include "zlib.h"
 
 // from sha1.cpp
 struct TORRENT_EXPORT SHA1_CTX
@@ -51,12 +52,6 @@ TORRENT_EXPORT void SHA1Init(SHA1_CTX* context);
 TORRENT_EXPORT void SHA1Update(SHA1_CTX* context, boost::uint8_t const* data, boost::uint32_t len);
 TORRENT_EXPORT void SHA1Final(SHA1_CTX* context, boost::uint8_t* digest);
 
-extern "C"
-{
-	// from zlib/adler32.c
-	unsigned long adler32(unsigned long adler, const char* data, unsigned int len);
-}
-
 namespace libtorrent
 {
 
@@ -69,7 +64,7 @@ namespace libtorrent
 		{
 			assert(data != 0);
 			assert(len > 0);
-			m_adler = adler32(m_adler, data, len);
+			m_adler = adler32(m_adler, (const Bytef*)data, len);
 		}
 		unsigned long final() const { return m_adler; }
 		void reset() { m_adler = adler32(0, 0, 0); }
diff --git a/include/libtorrent/pch.hpp b/include/libtorrent/pch.hpp
new file mode 100644
index 000000000..735999826
--- /dev/null
+++ b/include/libtorrent/pch.hpp
@@ -0,0 +1,96 @@
+#ifdef BOOST_BUILD_PCH_ENABLED
+
+#include <algorithm>
+#include <asio/ip/host_name.hpp>
+#include <assert.h>
+#include <bitset>
+#include <boost/array.hpp>
+#include <boost/bind.hpp>
+#include <boost/config.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/date_time/gregorian/gregorian_types.hpp>
+#include <boost/date_time/posix_time/posix_time.hpp>
+#include <boost/date_time/posix_time/posix_time_types.hpp>
+#include <boost/date_time/posix_time/ptime.hpp>
+#include <boost/detail/atomic_count.hpp>
+#include <boost/enable_shared_from_this.hpp>
+#include <boost/filesystem/convenience.hpp>
+#include <boost/filesystem/exception.hpp>
+#include <boost/filesystem/fstream.hpp>
+#include <boost/filesystem/operations.hpp>
+#include <boost/filesystem/path.hpp>
+#include <boost/function.hpp>
+#include <boost/integer_traits.hpp>
+#include <boost/intrusive_ptr.hpp>
+#include <boost/iterator/iterator_categories.hpp>
+#include <boost/iterator/iterator_facade.hpp>
+#include <boost/iterator/transform_iterator.hpp>
+#include <boost/iterator_adaptors.hpp>
+#include <boost/lexical_cast.hpp>
+#include <boost/limits.hpp>
+#include <boost/multi_index/member.hpp>
+#include <boost/multi_index/ordered_index.hpp>
+#include <boost/multi_index_container.hpp>
+#include <boost/next_prior.hpp>
+#include <boost/noncopyable.hpp>
+#include <boost/optional.hpp>
+#include <boost/preprocessor/repetition/enum.hpp>
+#include <boost/preprocessor/repetition/enum_params.hpp>
+#include <boost/preprocessor/repetition/enum_params_with_a_default.hpp>
+#include <boost/preprocessor/repetition/enum_shifted_params.hpp>
+#include <boost/ref.hpp>
+#include <boost/scoped_ptr.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/smart_ptr.hpp>
+#include <boost/static_assert.hpp>
+#include <boost/thread.hpp>
+#include <boost/thread/mutex.hpp>
+#include <boost/thread/recursive_mutex.hpp>
+#include <boost/tuple/tuple.hpp>
+#include <boost/utility.hpp>
+#include <boost/version.hpp>
+#include <boost/weak_ptr.hpp>
+#include <cassert>
+#include <cctype>
+#include <cmath>
+#include <cstdlib>
+#include <ctime>
+#include <cwchar>
+#include <deque>
+#include <fstream>
+#include <functional>
+#include <iomanip>
+#include <iostream>
+#include <iterator>
+#include <limits>
+#include <list>
+#include <map>
+#include <memory>
+#include <numeric>
+#include <queue>
+#include <set>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <typeinfo>
+#include <utility>
+#include <vector>
+#include <zlib.h>
+
+#ifdef __OBJC__
+#define Protocol Protocol_
+#endif
+
+#include <asio/ip/tcp.hpp>
+#include <asio/ip/udp.hpp>
+#include <asio/io_service.hpp>
+#include <asio/deadline_timer.hpp>
+#include <asio/write.hpp>
+#include <asio/strand.hpp>
+
+#ifdef __OBJC__ 
+#undef Protocol
+#endif
+
+#endif
+
diff --git a/include/libtorrent/storage.hpp b/include/libtorrent/storage.hpp
index 67774a7ea..5e545186e 100755
--- a/include/libtorrent/storage.hpp
+++ b/include/libtorrent/storage.hpp
@@ -126,7 +126,7 @@ namespace libtorrent
 		bool check_fastresume(aux::piece_checker_data& d
 			, std::vector<bool>& pieces, int& num_pieces, bool compact_mode);
 		std::pair<bool, float> check_files(std::vector<bool>& pieces
-			, int& num_pieces);
+			, int& num_pieces, boost::recursive_mutex& mutex);
 
 		void release_files();
 
diff --git a/src/Makefile.am b/src/Makefile.am
index 71bf4b150..7b0300d3c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -51,6 +51,7 @@ $(top_srcdir)/include/libtorrent/peer_connection.hpp \
 $(top_srcdir)/include/libtorrent/bt_peer_connection.hpp \
 $(top_srcdir)/include/libtorrent/web_peer_connection.hpp \
 $(top_srcdir)/include/libtorrent/natpmp.hpp \
+$(top_srcdir)/include/libtorrent/pch.hpp \
 $(top_srcdir)/include/libtorrent/peer_id.hpp \
 $(top_srcdir)/include/libtorrent/peer_info.hpp \
 $(top_srcdir)/include/libtorrent/peer_request.hpp \
diff --git a/src/alert.cpp b/src/alert.cpp
index 781265b92..066458cdf 100755
--- a/src/alert.cpp
+++ b/src/alert.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include "libtorrent/alert.hpp"
 
 namespace libtorrent {
diff --git a/src/allocate_resources.cpp b/src/allocate_resources.cpp
index 7e342ee95..deef06dc4 100644
--- a/src/allocate_resources.cpp
+++ b/src/allocate_resources.cpp
@@ -42,6 +42,8 @@ POSSIBILITY OF SUCH DAMAGE.
 //generation of the min and max macros in Visual C++, #define 
 //NOMINMAX before #including <windows.h>.
 
+#include "libtorrent/pch.hpp"
+
 #ifdef _WIN32
     //support boost1.32.0(2004-11-19 18:47)
     //now all libs can be compiled and linked with static module
diff --git a/src/bandwidth_manager.cpp b/src/bandwidth_manager.cpp
index a5868d439..7995fab13 100644
--- a/src/bandwidth_manager.cpp
+++ b/src/bandwidth_manager.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include "libtorrent/invariant_check.hpp"
 #include "libtorrent/bandwidth_manager.hpp"
 #include "libtorrent/peer_connection.hpp"
diff --git a/src/bt_peer_connection.cpp b/src/bt_peer_connection.cpp
index ed6e93a07..8b4f02904 100755
--- a/src/bt_peer_connection.cpp
+++ b/src/bt_peer_connection.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <iostream>
 #include <iomanip>
diff --git a/src/entry.cpp b/src/entry.cpp
index 55cbc3649..6506ed4c2 100755
--- a/src/entry.cpp
+++ b/src/entry.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <algorithm>
 #include <iomanip>
 #include "libtorrent/entry.hpp"
diff --git a/src/escape_string.cpp b/src/escape_string.cpp
index 80d134ed7..02a4fa085 100755
--- a/src/escape_string.cpp
+++ b/src/escape_string.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <string>
 #include <cassert>
 #include <stdexcept>
diff --git a/src/file.cpp b/src/file.cpp
index 2542f31de..28fea84b6 100755
--- a/src/file.cpp
+++ b/src/file.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #ifdef _WIN32
 // windows part
 #include "libtorrent/utf8.hpp"
diff --git a/src/file_pool.cpp b/src/file_pool.cpp
index f980a0f23..2b71fd4c0 100644
--- a/src/file_pool.cpp
+++ b/src/file_pool.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include "libtorrent/file_pool.hpp"
 
 #include <iostream>
diff --git a/src/http_tracker_connection.cpp b/src/http_tracker_connection.cpp
index f546df114..8db836096 100755
--- a/src/http_tracker_connection.cpp
+++ b/src/http_tracker_connection.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <iostream>
 #include <cctype>
diff --git a/src/identify_client.cpp b/src/identify_client.cpp
index bfc06363c..3d1f7e024 100755
--- a/src/identify_client.cpp
+++ b/src/identify_client.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <cctype>
 #include <algorithm>
 
diff --git a/src/ip_filter.cpp b/src/ip_filter.cpp
index 0afb5a346..92ea711c7 100644
--- a/src/ip_filter.cpp
+++ b/src/ip_filter.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include "libtorrent/ip_filter.hpp"
 #include <boost/utility.hpp>
 //#include <iostream>
diff --git a/src/kademlia/closest_nodes.cpp b/src/kademlia/closest_nodes.cpp
index e8bb9781c..e461bc453 100644
--- a/src/kademlia/closest_nodes.cpp
+++ b/src/kademlia/closest_nodes.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <libtorrent/kademlia/closest_nodes.hpp>
 #include <libtorrent/kademlia/routing_table.hpp>
 #include <libtorrent/kademlia/rpc_manager.hpp>
diff --git a/src/kademlia/dht_tracker.cpp b/src/kademlia/dht_tracker.cpp
index 3b2e9a50b..f5aaf4ffc 100644
--- a/src/kademlia/dht_tracker.cpp
+++ b/src/kademlia/dht_tracker.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <fstream>
 #include <set>
 #include <numeric>
diff --git a/src/kademlia/find_data.cpp b/src/kademlia/find_data.cpp
index 9fe787807..8b47e52cf 100644
--- a/src/kademlia/find_data.cpp
+++ b/src/kademlia/find_data.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <libtorrent/kademlia/find_data.hpp>
 #include <libtorrent/kademlia/routing_table.hpp>
 #include <libtorrent/kademlia/rpc_manager.hpp>
diff --git a/src/kademlia/node.cpp b/src/kademlia/node.cpp
index 07da958bb..4de002b95 100644
--- a/src/kademlia/node.cpp
+++ b/src/kademlia/node.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <utility>
 #include <boost/bind.hpp>
 #include <boost/optional.hpp>
diff --git a/src/kademlia/node_id.cpp b/src/kademlia/node_id.cpp
index d435846d2..4ed413714 100644
--- a/src/kademlia/node_id.cpp
+++ b/src/kademlia/node_id.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <algorithm>
 #include <iomanip>
 #include <cassert>
diff --git a/src/kademlia/refresh.cpp b/src/kademlia/refresh.cpp
index ccd753de9..9536540d6 100644
--- a/src/kademlia/refresh.cpp
+++ b/src/kademlia/refresh.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <libtorrent/kademlia/refresh.hpp>
 #include <libtorrent/kademlia/routing_table.hpp>
 #include <libtorrent/kademlia/rpc_manager.hpp>
diff --git a/src/kademlia/routing_table.cpp b/src/kademlia/routing_table.cpp
index 32f7514f2..c09176765 100644
--- a/src/kademlia/routing_table.cpp
+++ b/src/kademlia/routing_table.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <deque>
 #include <algorithm>
diff --git a/src/kademlia/rpc_manager.cpp b/src/kademlia/rpc_manager.cpp
index 25079adea..12f0defba 100644
--- a/src/kademlia/rpc_manager.cpp
+++ b/src/kademlia/rpc_manager.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <boost/date_time/posix_time/posix_time_types.hpp>
 #include <boost/date_time/posix_time/ptime.hpp>
 #include <boost/bind.hpp>
diff --git a/src/kademlia/traversal_algorithm.cpp b/src/kademlia/traversal_algorithm.cpp
index 1efe76e77..3dcfcaecf 100644
--- a/src/kademlia/traversal_algorithm.cpp
+++ b/src/kademlia/traversal_algorithm.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <libtorrent/kademlia/traversal_algorithm.hpp>
 #include <libtorrent/kademlia/routing_table.hpp>
 #include <libtorrent/kademlia/rpc_manager.hpp>
diff --git a/src/logger.cpp b/src/logger.cpp
index be101d02c..c8f6f7a74 100644
--- a/src/logger.cpp
+++ b/src/logger.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #ifdef _MSC_VER
 #pragma warning(push, 1)
 #endif
diff --git a/src/metadata_transfer.cpp b/src/metadata_transfer.cpp
index 3777cd71e..0bb2623df 100644
--- a/src/metadata_transfer.cpp
+++ b/src/metadata_transfer.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #ifdef _MSC_VER
 #pragma warning(push, 1)
 #endif
diff --git a/src/natpmp.cpp b/src/natpmp.cpp
index 4b0266157..ba89e1c80 100644
--- a/src/natpmp.cpp
+++ b/src/natpmp.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <libtorrent/natpmp.hpp>
 #include <libtorrent/io.hpp>
 #include <boost/bind.hpp>
@@ -302,7 +304,7 @@ void natpmp::on_reply(asio::error_code const& e
 				case 2: errmsg << "Not authorized to create port map (enable NAT-PMP on your router)"; break;
 				case 3: errmsg << "Network failure"; break;
 				case 4: errmsg << "Out of resources"; break;
-				case 5: errmsg << "Unsupported opcpde"; break;
+				case 5: errmsg << "Unsupported opcode"; break;
 			}
 			throw std::runtime_error(errmsg.str());
 		}
diff --git a/src/peer_connection.cpp b/src/peer_connection.cpp
index d43d20192..78e561f65 100755
--- a/src/peer_connection.cpp
+++ b/src/peer_connection.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <iostream>
 #include <iomanip>
diff --git a/src/piece_picker.cpp b/src/piece_picker.cpp
index 9efa2c861..5e29ec9dc 100755
--- a/src/piece_picker.cpp
+++ b/src/piece_picker.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <cmath>
 #include <algorithm>
diff --git a/src/policy.cpp b/src/policy.cpp
index 785e21fad..067cdcb8f 100755
--- a/src/policy.cpp
+++ b/src/policy.cpp
@@ -30,9 +30,9 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
-#include <iostream>
+#include "libtorrent/pch.hpp"
 
-#include "libtorrent/peer_connection.hpp"
+#include <iostream>
 
 #ifdef _MSC_VER
 #pragma warning(push, 1)
@@ -45,6 +45,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #pragma warning(pop)
 #endif
 
+#include "libtorrent/peer_connection.hpp"
 #include "libtorrent/web_peer_connection.hpp"
 #include "libtorrent/policy.hpp"
 #include "libtorrent/torrent.hpp"
diff --git a/src/session.cpp b/src/session.cpp
index a9b8280b1..7d0ca8983 100755
--- a/src/session.cpp
+++ b/src/session.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <ctime>
 #include <iostream>
 #include <fstream>
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index f2a90fc6d..29066a3b6 100755
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <ctime>
 #include <iostream>
 #include <fstream>
diff --git a/src/sha1.cpp b/src/sha1.cpp
index 1d04b4a17..e198c45a0 100755
--- a/src/sha1.cpp
+++ b/src/sha1.cpp
@@ -10,6 +10,8 @@ By Steve Reid <sreid@sea-to-sky.net>
 changelog at the end of the file.
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <cstdio>
 #include <cstring>
 
diff --git a/src/stat.cpp b/src/stat.cpp
index c36bd3725..d695edc42 100755
--- a/src/stat.cpp
+++ b/src/stat.cpp
@@ -35,11 +35,13 @@ POSSIBILITY OF SUCH DAMAGE.
 // per second and one (low pass-filter) for rates < 1
 // packet per second.
 
+#include "libtorrent/pch.hpp"
+
 #include <numeric>
+#include <algorithm>
 
 #include "libtorrent/stat.hpp"
 #include "libtorrent/invariant_check.hpp"
-#include <algorithm>
 
 #if defined _MSC_VER && _MSC_VER <= 1200
 #define for if (false) {} else for
diff --git a/src/storage.cpp b/src/storage.cpp
index 11eacd9f9..59632263e 100755
--- a/src/storage.cpp
+++ b/src/storage.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <ctime>
 #include <iterator>
 #include <algorithm>
@@ -716,7 +718,7 @@ namespace libtorrent
 
 		std::pair<bool, float> check_files(
 			std::vector<bool>& pieces
-			, int& num_pieces);
+			, int& num_pieces, boost::recursive_mutex& mutex);
 
 		void release_files();
 
@@ -764,7 +766,8 @@ namespace libtorrent
 			, int current_slot
 			, std::vector<bool>& have_pieces
 			, int& num_pieces
-			, const std::multimap<sha1_hash, int>& hash_to_piece);
+			, const std::multimap<sha1_hash, int>& hash_to_piece
+			, boost::recursive_mutex& mutex);
 
 		int allocate_slot_for_piece(int piece_index);
 #ifndef NDEBUG
@@ -1063,7 +1066,8 @@ namespace libtorrent
 		, int current_slot
 		, std::vector<bool>& have_pieces
 		, int& num_pieces
-		, const std::multimap<sha1_hash, int>& hash_to_piece)
+		, const std::multimap<sha1_hash, int>& hash_to_piece
+		, boost::recursive_mutex& mutex)
 	{
 //		INVARIANT_CHECK;
 
@@ -1123,6 +1127,9 @@ namespace libtorrent
 		{
 			const int piece_index = current_slot;
 
+			// lock because we're writing to have_pieces
+			boost::recursive_mutex::scoped_lock l(mutex);
+
 			if (have_pieces[piece_index])
 			{
 				// we have already found a piece with
@@ -1192,6 +1199,9 @@ namespace libtorrent
 
 		if (free_piece >= 0)
 		{
+			// lock because we're writing to have_pieces
+			boost::recursive_mutex::scoped_lock l(mutex);
+
 			assert(have_pieces[free_piece] == false);
 			assert(m_piece_to_slot[free_piece] == has_no_slot);
 			have_pieces[free_piece] = true;
@@ -1304,7 +1314,7 @@ namespace libtorrent
 	// file check is at. 0 is nothing done, and 1
 	// is finished
 	std::pair<bool, float> piece_manager::impl::check_files(
-		std::vector<bool>& pieces, int& num_pieces)
+		std::vector<bool>& pieces, int& num_pieces, boost::recursive_mutex& mutex)
 	{
 		assert(num_pieces == std::count(pieces.begin(), pieces.end(), true));
 
@@ -1395,7 +1405,8 @@ namespace libtorrent
 				, m_current_slot
 				, pieces
 				, num_pieces
-				, m_hash_to_piece);
+				, m_hash_to_piece
+				, mutex);
 
 			assert(num_pieces == std::count(pieces.begin(), pieces.end(), true));
 			assert(piece_index == unassigned || piece_index >= 0);
@@ -1664,9 +1675,10 @@ namespace libtorrent
 
 	std::pair<bool, float> piece_manager::check_files(
 		std::vector<bool>& pieces
-		, int& num_pieces)
+		, int& num_pieces
+		, boost::recursive_mutex& mutex)
 	{
-		return m_pimpl->check_files(pieces, num_pieces);
+		return m_pimpl->check_files(pieces, num_pieces, mutex);
 	}
 
 	int piece_manager::impl::allocate_slot_for_piece(int piece_index)
diff --git a/src/torrent.cpp b/src/torrent.cpp
index da9f863e6..557765cf1 100755
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -29,6 +29,9 @@ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.
 
 */
+
+#include "libtorrent/pch.hpp"
+
 #include <ctime>
 #include <iostream>
 #include <fstream>
@@ -2099,7 +2102,8 @@ namespace libtorrent
 		std::pair<bool, float> progress(true, 1.f);
 		try
 		{
-			progress = m_storage->check_files(m_have_pieces, m_num_pieces);
+			progress = m_storage->check_files(m_have_pieces, m_num_pieces
+				, m_ses.m_mutex);
 		}
 		catch (std::exception& e)
 		{
diff --git a/src/torrent_handle.cpp b/src/torrent_handle.cpp
index dcc46fd47..75a2c65c6 100755
--- a/src/torrent_handle.cpp
+++ b/src/torrent_handle.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <ctime>
 #include <iostream>
 #include <fstream>
diff --git a/src/torrent_info.cpp b/src/torrent_info.cpp
index 238864283..7aacdc355 100755
--- a/src/torrent_info.cpp
+++ b/src/torrent_info.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <ctime>
 #include <iostream>
 #include <fstream>
diff --git a/src/tracker_manager.cpp b/src/tracker_manager.cpp
index f27620072..ed3f6b620 100755
--- a/src/tracker_manager.cpp
+++ b/src/tracker_manager.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <iostream>
 #include <cctype>
diff --git a/src/udp_tracker_connection.cpp b/src/udp_tracker_connection.cpp
index 8726d6917..c284e1b14 100755
--- a/src/udp_tracker_connection.cpp
+++ b/src/udp_tracker_connection.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <iostream>
 #include <cctype>
diff --git a/src/ut_pex.cpp b/src/ut_pex.cpp
index e1da13f76..6006efbdc 100644
--- a/src/ut_pex.cpp
+++ b/src/ut_pex.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #ifdef _MSC_VER
 #pragma warning(push, 1)
 #endif
diff --git a/src/web_peer_connection.cpp b/src/web_peer_connection.cpp
index 2f6794cd5..c2b199de1 100755
--- a/src/web_peer_connection.cpp
+++ b/src/web_peer_connection.cpp
@@ -30,6 +30,8 @@ POSSIBILITY OF SUCH DAMAGE.
 
 */
 
+#include "libtorrent/pch.hpp"
+
 #include <vector>
 #include <iostream>
 #include <iomanip>