add a tracefs test

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm/.gitignore

@@ -72,6 +72,7 @@
 /static/mmx00
 /static/mnt_ext_auto
 /static/mnt_ext_master
+/static/mnt_tracefs
 /static/mnt_ro_bind
 /static/mntns_deleted
 /static/mntns_link_ghost

test/zdtm/static/Makefile

@@ -236,6 +236,7 @@ TST_DIR		=				\
 		mnt_ext_auto			\
 		mnt_ext_master			\
 		mnt_ext_dev			\
+		mnt_tracefs			\
 		mntns_deleted			\
 		unlink_regular00		\
 		mnt_enablefs			\

test/zdtm/static/mnt_tracefs.c

+#include <sys/mount.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <linux/limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc	= "Test c/r of tracefs";
+const char *test_author	= "Tycho Andersen <tycho.andersen@canonical.com>";
+
+char *dirname = "mnt_tracefs.test";
+TEST_OPTION(dirname, string, "directory name", 1);
+
+int main(int argc, char ** argv)
+{
+	char dst[PATH_MAX], *root;
+	int status;
+	pid_t pid;
+
+	root = getenv("ZDTM_ROOT");
+	if (root == NULL) {
+		pr_perror("root");
+		return 1;
+	}
+
+	sprintf(dst, "%s/debugfs", getenv("ZDTM_ROOT"));
+
+	if (strcmp(getenv("ZDTM_NEWNS"), "1"))
+		goto test;
+
+	pid = fork();
+	if (pid < 0)
+		return 1;
+	if (pid == 0) {
+		test_ext_init(argc, argv);
+
+		mkdir(dst, 755);
+		if (mount("/sys/kernel/debug", dst, NULL, MS_BIND, NULL)) {
+			pr_perror("mount");
+			return 1;
+		}
+		return 0;
+	}
+
+	wait(&status);
+	if (status != 0)
+		return 1;
+
+test:
+	test_init(argc, argv);
+
+	test_daemon();
+	test_waitsig();
+
+
+	pass();
+
+	return 0;
+}
+

test/zdtm/static/mnt_tracefs.checkskip

+#!/bin/bash
+
+# tracefs is automatically mounted under debugfs if the kernel has it, so we
+# just need to check for a file in the tracing directory.
+test -f /sys/kernel/debug/tracing/README || exit 1

test/zdtm/static/mnt_tracefs.desc

+{'flavor': 'uns', 'feature': 'mnt_id', 'opts': '--ext-mount-map auto --enable-external-masters'}