zdtm: add a test to check O_TMPFILE

man 2 open:
...
O_TMPFILE (since Linux 3.11)

Create  an unnamed temporary file.  The pathname argument speci‐ fies a
directory; an unnamed  inode  will  be  created  in  that directory's
filesystem.  Anything written to the resulting file will be lost when
the last file descriptor is closed, unless the file is given a name.
...
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

test/zdtm/static/Makefile

@@ -307,6 +307,7 @@ TST_DIR		=				\
 		cgroup_ifpriomap		\
 		cgroup_stray		\
 		unlink_fstat04			\
+		unlink_fstat041			\
 		mntns_remap			\
 		mntns_open			\
 		mntns_link_remap		\
@@ -489,6 +490,7 @@ mlock_setuid: get_smaps_bits.o
 inotify01:		CFLAGS += -DINOTIFY01
 unlink_fstat01+:	CFLAGS += -DUNLINK_OVER
 unlink_fstat04:		CFLAGS += -DUNLINK_FSTAT04
+unlink_fstat041:		CFLAGS += -DUNLINK_FSTAT041 -DUNLINK_FSTAT04
 ghost_holes01:		CFLAGS += -DTAIL_HOLE
 ghost_holes02:		CFLAGS += -DHEAD_HOLE
 sk-freebind-false:	CFLAGS += -DZDTM_FREEBIND_FALSE

test/zdtm/static/unlink_fstat00.c

@@ -40,7 +40,11 @@ int main(int argc, char ** argv)
 
 	mkdir(dirname, 0700);
 #endif
+#ifndef UNLINK_FSTAT041
 	fd = open(filename, O_RDWR | O_CREAT | O_TRUNC, 0644);
+#else
+	fd = open(dirname, O_RDWR | O_TMPFILE, 0644);
+#endif
 	if (fd < 0) {
 		pr_perror("can't open %s", filename);
 		exit(1);
@@ -58,10 +62,12 @@ int main(int argc, char ** argv)
 		goto failed;
 	}
 
+#ifndef UNLINK_FSTAT041
 	if (unlink(filename) < 0) {
 		pr_perror("can't unlink %s", filename);
 		goto failed;
 	}
+#endif
 	/* Change file size */
 	if (fst.st_size != 0) {
 		pr_perror("%s file size eq %ld", filename, (long)fst.st_size);

test/zdtm/static/unlink_fstat041.c

+unlink_fstat00.c
\ No newline at end of file