zdtm: Tests for testing completely unlinked files

This includes existing test and a new one, checking that
unlinked hardlinks are handled properly.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm.sh

@@ -38,6 +38,8 @@ static/socket_udp
 static/socket_udplite
 static/selfexe00
 static/file_fown
+static/unlink_fstat00
+static/unlink_fstat02
 "
 
 UTS_TEST_LIST="

test/zdtm/live/static/Makefile

@@ -55,6 +55,7 @@ TST_FILE	=				\
 		deleted_dev			\
 		unlink_fstat00			\
 		unlink_fstat01			\
+		unlink_fstat02			\
 		unlink_largefile		\
 		mtime_mmap			\
 		fifo				\

test/zdtm/live/static/unlink_fstat02.c

+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "zdtmtst.h"
+
+const char *test_doc	= "Open, link, unlink x2, change size, migrate, check size";
+
+char *filename;
+TEST_OPTION(filename, string, "file name", 1);
+static char link_name[1024];
+
+int main(int argc, char ** argv)
+{
+	int fd[2];
+	size_t fsize=1000;
+	uint8_t buf[fsize];
+	struct stat fst, fst2;
+
+	test_init(argc, argv);
+
+	fd[0] = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+	if (fd[0] < 0) {
+		err("can't open %s: %m\n", filename);
+		exit(1);
+	}
+
+	sprintf(link_name, "%s.link", filename);
+	if (link(filename, link_name)) {
+		err("can't link files");
+		goto failed0;
+	}
+
+	fd[1] = open(link_name, O_RDONLY);
+	if (fd[1] < 0) {
+		err("can't open %s: %m\n", link_name);
+		goto failed0;
+	}
+
+	if (fstat(fd[0], &fst) < 0) {
+		err("can't get file info %s before: %m\n", filename);
+		goto failed;
+	}
+
+	if (fst.st_size != 0) {
+		err("%s file size eq %d\n", fst.st_size);
+		goto failed;
+	}
+
+	if (unlink(filename) < 0) {
+		err("can't unlink %s: %m\n", filename);
+		goto failed;
+	}
+
+	if (unlink(link_name) < 0) {
+		err("can't unlink %s: %m\n", link_name);
+		goto failed;
+	}
+
+	memset(buf, '0', sizeof(buf));
+	if (write(fd[0], buf, sizeof(buf)) != sizeof(buf)) {
+		err("can't write %s: %m\n", filename);
+		goto failed;
+	}
+
+	test_daemon();
+	test_waitsig();
+
+	if (fstat(fd[0], &fst) < 0) {
+		err("can't get %s file info after: %m\n", filename);
+		goto failed;
+	}
+
+	if (fstat(fd[1], &fst2) < 0) {
+		err("can't get %s file2 info after: %m\n", link_name);
+		goto failed;
+	}
+
+	if ((fst.st_dev != fst2.st_dev) || (fst.st_ino != fst2.st_ino)) {
+		fail("files differ after restore\n");
+		goto failed;
+	}
+
+	if (fst.st_size != fsize) {
+		fail("(via fstat): file size changed to %d", fst.st_size);
+		goto failed;
+	}
+
+	fst.st_size = lseek(fd[0], 0, SEEK_END);
+	if (fst.st_size != fsize) {
+		fail("(via lseek): file size changed to %d", fst.st_size);
+		goto failed;
+	}
+
+	close(fd[0]);
+	close(fd[1]);
+
+	pass();
+	return 0;
+
+failed:
+	unlink(link_name);
+	close(fd[1]);
+failed0:
+	unlink(filename);
+	close(fd[0]);
+	return 1;
+}