[bcache_t] Add block cache test case for issue 80

unit-tests/Makefile.in

@@ -48,6 +48,7 @@ TEST_SOURCE=\
 	unit-tests/array_block_t.cc \
 	unit-tests/array_t.cc \
 	unit-tests/base64_t.cc \
+	unit-tests/bcache_t.cc \
 	unit-tests/block_t.cc \
 	unit-tests/bitset_t.cc \
 	unit-tests/btree_t.cc \

unit-tests/bcache_t.cc

@@ -0,0 +1,70 @@
+// Copyright (C) 2017 Red Hat, Inc. All rights reserved.
+//
+// This file is part of the thin-provisioning-tools source.
+//
+// thin-provisioning-tools is free software: you can redistribute it
+// and/or modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// thin-provisioning-tools is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along
+// with thin-provisioning-tools.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+#include "gmock/gmock.h"
+#include "block-cache/block_cache.h"
+#include "test_utils.h"
+
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+using namespace std;
+using namespace test;
+using namespace testing;
+
+//----------------------------------------------------------------
+
+TEST(BCacheTests, cleaned_on_demand)
+{
+	using namespace bcache;
+
+	unsigned const NR_BLOCKS = 16;
+
+	temp_file tmp("bcache_t", 1);
+	int fd = open(tmp.get_path().c_str(), O_RDWR | O_DIRECT, 0666);
+
+	uint64_t bs = 8;
+	block_cache bc(fd, bs, 64, (bs << SECTOR_SHIFT) * NR_BLOCKS);
+	validator::ptr v(new bcache::noop_validator());
+	for (unsigned i = 0; i < NR_BLOCKS; i++) {
+		block_cache::block &b = bc.get(i, block_cache::GF_DIRTY | block_cache::GF_ZERO, v);
+		b.put();
+	}
+
+	// Default WRITEBACK_LOW_THRESHOLD_PERCENT == 33
+	// For NR_BLOCKS cache entires, only 6 dirty blocks will be submitted,
+	// so the 7th get() doesn't work.
+	list<block_cache::block *> blocks;
+
+	try {
+		for (unsigned i = 0; i < NR_BLOCKS; i++)
+			blocks.push_back(&bc.get(NR_BLOCKS + i, 0, v));
+
+	} catch (...) {
+		for (auto b : blocks)
+			b->put();
+
+		throw;
+	}
+
+	for (auto b : blocks)
+		b->put();
+}
+