zdtm: Add unlink_regular00 test

Test checks that a deleted file content in a deleted parent directory
restores right. Initially directory is created in a separate mount,
to check the ghost file is created in right mount and link() in
rfi_remap() is working.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>

test/zdtm/live/static/Makefile

@@ -225,6 +225,7 @@ TST_DIR		=				\
 		mnt_ext_master			\
 		mntns_deleted			\
 		binfmt_misc			\
+		unlink_regular00		\
 
 TST_DIR_FILE	=				\
 		chroot				\

test/zdtm/live/static/unlink_regular00.c

+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mount.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc = "Checkpointing/restore of unlinked file inside unlinked directory";
+const char *test_author	= "Kirill Tkhai <ktkhai@virtuozzo.com>";
+
+char *dirname;
+TEST_OPTION(dirname, string, "directory name", 1);
+
+#define SUBDIR "subdir"
+#define FNAME "testfile"
+#define MSG "Hello!!!111"
+
+int main(int argc, char ** argv)
+{
+	char subdir[PATH_MAX], fname[PATH_MAX], lname[PATH_MAX];
+	char buf[sizeof(MSG) + 1];
+	int fd, ret = -1;
+
+	test_init(argc, argv);
+
+	memset(buf, 0, sizeof(buf));
+
+	if (mkdir(dirname, 0777)) {
+		fail("can't create %s", dirname);
+		exit(1);
+	}
+
+	if (mount("none", dirname, "tmpfs", 0, "") < 0) {
+		fail("can't mount tmpfs to %s", dirname);
+		goto rm_topdir;
+	}
+
+	sprintf(subdir, "%s/" SUBDIR, dirname);
+
+	if (mkdir(subdir, 0777)) {
+		fail("can't create %s", subdir);
+		goto umount;
+	}
+
+	sprintf(fname, "%s/" SUBDIR "/" FNAME, dirname);
+	sprintf(lname, "%s/" FNAME, dirname);
+
+	fd = open(fname, O_RDWR | O_CREAT, 0644);
+	if (fd < 0) {
+		fail("can't open %s", fname);
+		rmdir(subdir);
+		goto umount;
+	}
+
+	if (link(fname, lname) < 0) {
+		fail("can't link %s to %s", fname, lname);
+		unlink(fname);
+		rmdir(subdir);
+		goto umount;
+	}
+
+	if (unlink(fname) || rmdir(subdir)) {
+		fail("can't unlink %s or %s", fname, subdir);
+		goto close_file;
+	}
+
+	if (write(fd, MSG, sizeof(MSG)) != sizeof(MSG)) {
+		fail("can't write %s", fname);
+		goto close_file;
+	}
+
+	test_daemon();
+	test_waitsig();
+
+	if (lseek(fd, 0, SEEK_SET) != 0) {
+		fail("can't lseek %s", fname);
+		goto close_file;
+	}
+
+	if (read(fd, buf, sizeof(MSG)) != sizeof(MSG)) {
+		fail("can't read %s", fname);
+		goto close_file;
+	}
+
+	if (strcmp(buf, MSG)) {
+		fail("content differs: %s, %s, sizeof=%d", buf, MSG, sizeof(MSG));
+		goto close_file;
+	}
+
+	ret = 0;
+	pass();
+
+close_file:
+	close(fd);
+	unlink(lname);
+umount:
+	if (umount(dirname) < 0)
+		pr_err("Can't umount\n");
+rm_topdir:
+	if (rmdir(dirname) < 0)
+		pr_err("Can't rmdir()\n");
+
+	return ret;
+}

test/zdtm/live/static/unlink_regular00.desc

+{'flavor': 'ns', 'flags': 'suid'}