diff --git a/include/libtorrent/disk_io_thread.hpp b/include/libtorrent/disk_io_thread.hpp
index 1d5af07d3..c7f475f9c 100644
--- a/include/libtorrent/disk_io_thread.hpp
+++ b/include/libtorrent/disk_io_thread.hpp
@@ -97,7 +97,7 @@ namespace libtorrent
 
 		bool need_readback;
 	};
-	
+
 	// this struct holds a number of statistics counters
 	// relevant for the disk io thread and disk cache.
 	struct TORRENT_EXPORT cache_status
@@ -461,7 +461,7 @@ namespace libtorrent
 		// writes out the blocks [start, end) (releases the lock
 		// during the file operation)
 		int flush_range(cached_piece_entry* p, int start, int end
-			, int flags, tailqueue& completed_jobs, mutex::scoped_lock& l);
+			, tailqueue& completed_jobs, mutex::scoped_lock& l);
 
 		// low level flush operations, used by flush_range
 		int build_iovec(cached_piece_entry* pe, int start, int end
diff --git a/include/libtorrent/part_file.hpp b/include/libtorrent/part_file.hpp
index db8c74e0c..772744413 100644
--- a/include/libtorrent/part_file.hpp
+++ b/include/libtorrent/part_file.hpp
@@ -52,13 +52,13 @@ namespace libtorrent
 		// each piece being 'piece_size' number of bytes
 		part_file(std::string const& path, std::string const& name, int num_pieces, int piece_size);
 		~part_file();
-	
+
 		int writev(file::iovec_t const* bufs, int num_bufs, int piece, int offset, error_code& ec);
 		int readv(file::iovec_t const* bufs, int num_bufs, int piece, int offset, error_code& ec);
 
 		// free the slot the given piece is stored in. We no longer need to store this
 		// piece in the part file
-		void free_piece(int piece, error_code& ec);
+		void free_piece(int piece);
 
 		void move_partfile(std::string const& path, error_code& ec);
 
diff --git a/src/disk_io_thread.cpp b/src/disk_io_thread.cpp
index 98e09df18..cf2c91f85 100644
--- a/src/disk_io_thread.cpp
+++ b/src/disk_io_thread.cpp
@@ -346,7 +346,7 @@ namespace libtorrent
 			DLOG("try_flush_hashed: (%d) blocks_in_piece: %d end: %d\n"
 				, int(p->piece), int(p->blocks_in_piece), end);
 
-			return flush_range(p, 0, end, 0, completed_jobs, l);
+			return flush_range(p, 0, end, completed_jobs, l);
 		}
 
 		// piece range
@@ -713,7 +713,7 @@ namespace libtorrent
 	// issues write operations for blocks in the given
 	// range on the given piece.
 	int disk_io_thread::flush_range(cached_piece_entry* pe, int start, int end
-		, int flags, tailqueue& completed_jobs, mutex::scoped_lock& l)
+		, tailqueue& completed_jobs, mutex::scoped_lock& l)
 	{
 		TORRENT_ASSERT(l.locked());
 		INVARIANT_CHECK;
@@ -722,7 +722,7 @@ namespace libtorrent
 			, int(pe->piece), start, end);
 		TORRENT_PIECE_ASSERT(start >= 0, pe);
 		TORRENT_PIECE_ASSERT(start < end, pe);
-		
+
 		file::iovec_t* iov = TORRENT_ALLOCA(file::iovec_t, pe->blocks_in_piece);
 		int* flushing = TORRENT_ALLOCA(int, pe->blocks_in_piece);
 		int iov_len = build_iovec(pe, start, end, iov, flushing, 0);
@@ -791,7 +791,7 @@ namespace libtorrent
 		else if ((flags & flush_write_cache) && pe->num_dirty > 0)
 		{
 			// issue write commands
-			flush_range(pe, 0, INT_MAX, 0, completed_jobs, l);
+			flush_range(pe, 0, INT_MAX, completed_jobs, l);
 
 			// if we're also flushing the read cache, this piece
 			// should be removed as soon as all write jobs finishes
@@ -943,7 +943,7 @@ namespace libtorrent
 #endif
 			++pe->piece_refcount;
 
-			num -= flush_range(pe, 0, INT_MAX, 0, completed_jobs, l);
+			num -= flush_range(pe, 0, INT_MAX, completed_jobs, l);
 			--pe->piece_refcount;
 
 			m_disk_cache.maybe_free_piece(pe);
@@ -991,7 +991,7 @@ namespace libtorrent
 
 		for (int i = 0; i < num_flush; ++i)
 		{
-			flush_range(to_flush[i], 0, INT_MAX, 0, completed_jobs, l);
+			flush_range(to_flush[i], 0, INT_MAX, completed_jobs, l);
 			TORRENT_ASSERT(to_flush[i]->piece_refcount > 0);
 			--to_flush[i]->piece_refcount;
 			m_disk_cache.maybe_free_piece(to_flush[i]);
diff --git a/src/part_file.cpp b/src/part_file.cpp
index ad7abef9c..5050d66d5 100644
--- a/src/part_file.cpp
+++ b/src/part_file.cpp
@@ -102,20 +102,20 @@ namespace libtorrent
 			file::iovec_t b = {header.get(), size_t(m_header_size) };
 			int n = m_file.readv(0, &b, 1, ec);
 			if (ec) return;
-   
+
 			// we don't have a full header. consider the file empty
 			if (n < m_header_size) return;
 			using namespace libtorrent::detail;
-   
+
 			char* ptr = (char*)header.get();
 			// we have a header. Parse it
 			int num_pieces_ = read_uint32(ptr);
 			int piece_size_ = read_uint32(ptr);
-   
+
 			// if there is a mismatch in number of pieces or piece size
 			// consider the file empty and overwrite anything in there
 			if (num_pieces != num_pieces_ || m_piece_size != piece_size_) return;
-			
+
 			// this is used to determine which slots are free, and how many
 			// slots are allocated
 			std::vector<bool> free_slots;
@@ -125,14 +125,14 @@ namespace libtorrent
 			{
 				int slot = read_uint32(ptr);
 				if (slot == 0xffffffff) continue;
-   
+
 				// invalid part-file
 				TORRENT_ASSERT(slot < num_pieces);
 				if (slot >= num_pieces) continue;
-   
+
 				if (slot >= m_num_allocated)
 					m_num_allocated = slot + 1;
-   
+
 				free_slots[slot] = false;
 				m_piece_map[i] = slot;
 			}
@@ -152,7 +152,7 @@ namespace libtorrent
 		error_code ec;
 		flush_metadata_impl(ec);
 	}
-	
+
 	int part_file::allocate_slot(int piece)
 	{
 		// the mutex is assumed to be held here, since this is a private function
@@ -242,7 +242,7 @@ namespace libtorrent
 		}
 	}
 
-	void part_file::free_piece(int piece, error_code& ec)
+	void part_file::free_piece(int piece)
 	{
 		mutex::scoped_lock l(m_mutex);
 
@@ -316,16 +316,19 @@ namespace libtorrent
 			{
 				open_file(file::read_only, ec);
 				if (ec) return;
-				
+
 				if (!buf) buf.reset(new char[m_piece_size]);
 
 				boost::int64_t slot_offset = boost::int64_t(m_header_size) + boost::int64_t(i->second) * m_piece_size;
 				file::iovec_t v = { buf.get(), size_t(block_to_copy) };
 				int ret = m_file.readv(slot_offset + piece_offset, &v, 1, ec);
-				if (ec) return;
+				TORRENT_ASSERT(ec || ret == block_to_copy);
+				if (ec || ret != block_to_copy) return;
+
 
 				ret = f.writev(file_offset, &v, 1, ec);
-				if (ec) return;
+				TORRENT_ASSERT(ec || ret == block_to_copy);
+				if (ec || ret != block_to_copy) return;
 
 				if (block_to_copy == m_piece_size)
 				{
diff --git a/src/storage.cpp b/src/storage.cpp
index 618a2be93..032a431f7 100644
--- a/src/storage.cpp
+++ b/src/storage.cpp
@@ -190,7 +190,7 @@ namespace libtorrent
 			size += i->iov_len;
 		return size;
 	}
-	
+
 	TORRENT_EXTRA_EXPORT void clear_bufs(file::iovec_t const* bufs, int num_bufs)
 	{
 		for (file::iovec_t const* i = bufs, *end(bufs + num_bufs); i < end; ++i)
diff --git a/test/test_part_file.cpp b/test/test_part_file.cpp
index 93e516c16..3b6d7d7c9 100644
--- a/test/test_part_file.cpp
+++ b/test/test_part_file.cpp
@@ -118,8 +118,7 @@ int test_main()
 		pf.export_file(output, 10 * piece_size, 1024, ec);
 		if (ec) fprintf(stderr, "export_file: %s\n", ec.message().c_str());
 
-		pf.free_piece(10, ec);
-		if (ec) fprintf(stderr, "free_piece: %s\n", ec.message().c_str());
+		pf.free_piece(10);
 
 		pf.flush_metadata(ec);
 		if (ec) fprintf(stderr, "flush_metadata: %s\n", ec.message().c_str());