@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-or-later
CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES)
-TEST_GEN_PROGS := statmount_test statmount_test_ns
+TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test
include ../../lib.mk
new file mode 100644
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// Copyright (c) 2024 Christian Brauner <brauner@kernel.org>
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <sched.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/mount.h>
+#include <unistd.h>
+
+#include "statmount.h"
+#include "../../kselftest_harness.h"
+
+#ifndef LISTMOUNT_REVERSE
+#define LISTMOUNT_REVERSE (1 << 0) /* List later mounts first */
+#endif
+
+#define LISTMNT_BUFFER 10
+
+/* Check that all mount ids are in increasing order. */
+TEST(listmount_forward)
+{
+ uint64_t list[LISTMNT_BUFFER], last_mnt_id = 0;
+
+ for (;;) {
+ ssize_t nr_mounts;
+
+ nr_mounts = listmount(LSMT_ROOT, 0, last_mnt_id,
+ list, LISTMNT_BUFFER, 0);
+ ASSERT_GE(nr_mounts, 0);
+ if (nr_mounts == 0)
+ break;
+
+ for (size_t cur = 0; cur < nr_mounts; cur++) {
+ if (cur < nr_mounts - 1)
+ ASSERT_LT(list[cur], list[cur + 1]);
+ last_mnt_id = list[cur];
+ }
+ }
+}
+
+/* Check that all mount ids are in decreasing order. */
+TEST(listmount_backward)
+{
+ uint64_t list[LISTMNT_BUFFER], last_mnt_id = 0;
+
+ for (;;) {
+ ssize_t nr_mounts;
+
+ nr_mounts = listmount(LSMT_ROOT, 0, last_mnt_id,
+ list, LISTMNT_BUFFER, LISTMOUNT_REVERSE);
+ ASSERT_GE(nr_mounts, 0);
+ if (nr_mounts == 0)
+ break;
+
+ for (size_t cur = 0; cur < nr_mounts; cur++) {
+ if (cur < nr_mounts - 1)
+ ASSERT_GT(list[cur], list[cur + 1]);
+ last_mnt_id = list[cur];
+ }
+ }
+}
+
+TEST_HARNESS_MAIN
Add a forward and backward iteration test for listmount(). Signed-off-by: Christian Brauner <brauner@kernel.org> --- .../selftests/filesystems/statmount/Makefile | 2 +- .../filesystems/statmount/listmount_test.c | 66 ++++++++++++++++++++++ 2 files changed, 67 insertions(+), 1 deletion(-)