test: Check that criu's donwgrading quirk works

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -118,6 +118,7 @@ static/file_locks01
 static/file_locks02
 static/file_locks03
 static/file_locks04
+static/file_locks05
 static/sigpending
 static/sigaltstack
 static/sk-netlink

test/zdtm/live/static/Makefile

@@ -152,6 +152,7 @@ TST_FILE	=				\
 		file_locks02			\
 		file_locks03			\
 		file_locks04			\
+		file_locks05			\
 		netns-nf			\
 		maps_file_prot			\
 

test/zdtm/live/static/file_locks05.c

+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/file.h>
+#include <string.h>
+#include <sys/wait.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc	= "Sanity check for criu lock-test quirk";
+const char *test_author	= "Pavel Emelyanov <xemul@parallels.com>";
+
+char *filename;
+TEST_OPTION(filename, string, "file name", 1);
+
+int main(int argc, char **argv)
+{
+	int fd, fd2;
+
+	test_init(argc, argv);
+
+	fd = open(filename, O_CREAT | O_RDWR, 0600);
+	if (fd < 0) {
+		err("No file");
+		return -1;
+	}
+
+	fd2 = open(filename, O_RDWR);
+	if (fd2 < 0) {
+		err("No file2");
+		return -1;
+	}
+
+	flock(fd, LOCK_SH);
+
+	test_daemon();
+	test_waitsig();
+
+	if (flock(fd2, LOCK_SH) == 0)
+		pass();
+	else
+		fail("Flock file locks check failed");
+
+	close(fd);
+	close(fd2);
+	unlink(filename);
+
+	return 0;
+}

test/zdtm/live/static/file_locks05.opts

+--file-locks