test/multipath: add COMPARE AND WRITE test

Confirm that data is consistent across paths when using the atomic
COMPARE AND WRITE operation.
This should be extended in future to issue the requests simultaneously
across both paths, in an attempt to trigger a read/write race.

Signed-off-by: David Disseldorp <ddiss@suse.de>

test-tool/Makefile.am

@@ -216,7 +216,8 @@ iscsi_test_cu_SOURCES = iscsi-test-cu.c \
 	test_writeverify16_dpo.c \
 	test_writeverify16_residuals.c \
 	test_multipathio_simple.c \
-	test_multipathio_reset.c
+	test_multipathio_reset.c \
+	test_multipathio_compareandwrite.c
 
 endif
 

test-tool/iscsi-test-cu.c

@@ -446,6 +446,7 @@ static CU_TestInfo tests_writeverify16[] = {
 static CU_TestInfo tests_multipathio[] = {
 	{ (char *)"Simple", test_multipathio_simple },
 	{ (char *)"Reset", test_multipathio_reset },
+	{ (char *)"CompareAndWrite", test_multipathio_compareandwrite },
 	CU_TEST_INFO_NULL
 };
 

test-tool/iscsi-test-cu.h

@@ -302,5 +302,6 @@ void test_writeverify16_residuals(void);
 
 void test_multipathio_simple(void);
 void test_multipathio_reset(void);
+void test_multipathio_compareandwrite(void);
 
 #endif	/* _ISCSI_TEST_CU_H_ */

test-tool/test_multipathio_compareandwrite.c

@@ -0,0 +1,104 @@
+/*
+   Copyright (C) 2013 Ronnie Sahlberg <ronniesahlberg@gmail.com>
+   Copyright (C) 2015 David Disseldorp
+
+   This program 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 2 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <inttypes.h>
+#include <stdlib.h>
+
+#include <CUnit/CUnit.h>
+
+#include "iscsi.h"
+#include "scsi-lowlevel.h"
+#include "iscsi-support.h"
+#include "iscsi-test-cu.h"
+#include "iscsi-multipath.h"
+
+void
+test_multipathio_compareandwrite(void)
+{
+	int io_bl = 1;	/* 1 block CAW IOs */
+	int path;
+	int i, ret;
+	unsigned char *buf = alloca(2 * io_bl * block_size);
+	int maxbl;
+
+	CHECK_FOR_DATALOSS;
+	CHECK_FOR_SBC;
+	MPATH_SKIP_IF_UNAVAILABLE(mp_sds, mp_num_sds);
+
+	if (inq_bl) {
+		maxbl = inq_bl->max_cmp;
+	} else {
+		/* Assume we are not limited */
+		maxbl = 256;
+	}
+	if (maxbl < io_bl) {
+		CU_PASS("[SKIPPED] MAXIMUM_COMPARE_AND_WRITE_LENGTH too small");
+		return;
+	}
+
+	logging(LOG_VERBOSE, LOG_BLANK_LINE);
+	logging(LOG_VERBOSE, "Initialising data prior to COMPARE_AND_WRITE");
+
+	memset(buf, 0, io_bl * block_size);
+	ret = writesame10(mp_sds[0], 0,
+			  block_size, 256, 0, 0, 0, 0, buf,
+			  EXPECT_STATUS_GOOD);
+	if (ret == -2) {
+		CU_PASS("[SKIPPED] Target does not support WRITESAME10. Skipping test");
+		return;
+	}
+	CU_ASSERT_EQUAL(ret, 0);
+
+	logging(LOG_VERBOSE, "Test multipath COMPARE_AND_WRITE");
+	for (i = 0; i < 256; i++) {
+
+		for (path = 0; path < mp_num_sds; path++) {
+			logging(LOG_VERBOSE,
+				"Test COMPARE_AND_WRITE(%d->%d) using path %d",
+				path, path + 1, path);
+
+			/* compare data is first half */
+			memset(buf, path, io_bl * block_size);
+			/* write data is the second half, wrap around */
+			memset(buf + io_bl * block_size, path + 1,
+			       io_bl * block_size);
+
+			ret = compareandwrite(mp_sds[path], i,
+					      buf, 2 * io_bl * block_size,
+					      block_size, 0, 0, 0, 0,
+					      EXPECT_STATUS_GOOD);
+			if (ret == -2) {
+				CU_PASS("[SKIPPED] Target does not support "
+					"COMPARE_AND_WRITE. Skipping test");
+				return;
+			}
+			CU_ASSERT_EQUAL(ret, 0);
+
+			logging(LOG_VERBOSE,
+				"Test bad COMPARE_AND_WRITE(%d->%d)",
+				path, path + 1);
+
+			ret = compareandwrite(mp_sds[path], i,
+					      buf, 2 * io_bl * block_size,
+					      block_size, 0, 0, 0, 0,
+					      EXPECT_MISCOMPARE);
+			CU_ASSERT_EQUAL(ret, 0);
+		}
+	}
+}