[PATCH AUTOSEL 6.12 19/19] selftests: always check mask returned by statmount(2)

[Sasha Levin <sashal@kernel.org>]

From: Miklos Szeredi <mszeredi@redhat.com>

[ Upstream commit 2cc02059fbc79306b53a44b1f1a4444aa3c76598 ]

STATMOUNT_MNT_OPTS can actually be missing if there are no options.  This
is a change of behavior since 75ead69a7173 ("fs: don't let statmount return
empty strings").

The other checks shouldn't actually trigger, but add them for correctness
and for easier debugging if the test fails.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://lore.kernel.org/r/20250129160641.35485-1-mszeredi@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../filesystems/statmount/statmount_test.c    | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/filesystems/statmount/statmount_test.c b/tools/testing/selftests/filesystems/statmount/statmount_test.c
index c773334bbcc95..550e5d762c23f 100644
--- a/tools/testing/selftests/filesystems/statmount/statmount_test.c
+++ b/tools/testing/selftests/filesystems/statmount/statmount_test.c
@@ -383,6 +383,10 @@ static void test_statmount_mnt_point(void)
 		return;
 	}
 
+	if (!(sm->mask & STATMOUNT_MNT_POINT)) {
+		ksft_test_result_fail("missing STATMOUNT_MNT_POINT in mask\n");
+		return;
+	}
 	if (strcmp(sm->str + sm->mnt_point, "/") != 0) {
 		ksft_test_result_fail("unexpected mount point: '%s' != '/'\n",
 				      sm->str + sm->mnt_point);
@@ -408,6 +412,10 @@ static void test_statmount_mnt_root(void)
 				      strerror(errno));
 		return;
 	}
+	if (!(sm->mask & STATMOUNT_MNT_ROOT)) {
+		ksft_test_result_fail("missing STATMOUNT_MNT_ROOT in mask\n");
+		return;
+	}
 	mnt_root = sm->str + sm->mnt_root;
 	last_root = strrchr(mnt_root, '/');
 	if (last_root)
@@ -437,6 +445,10 @@ static void test_statmount_fs_type(void)
 				      strerror(errno));
 		return;
 	}
+	if (!(sm->mask & STATMOUNT_FS_TYPE)) {
+		ksft_test_result_fail("missing STATMOUNT_FS_TYPE in mask\n");
+		return;
+	}
 	fs_type = sm->str + sm->fs_type;
 	for (s = known_fs; s != NULL; s++) {
 		if (strcmp(fs_type, *s) == 0)
@@ -464,6 +476,11 @@ static void test_statmount_mnt_opts(void)
 		return;
 	}
 
+	if (!(sm->mask & STATMOUNT_MNT_BASIC)) {
+		ksft_test_result_fail("missing STATMOUNT_MNT_BASIC in mask\n");
+		return;
+	}
+
 	while (getline(&line, &len, f_mountinfo) != -1) {
 		int i;
 		char *p, *p2;
@@ -514,7 +531,10 @@ static void test_statmount_mnt_opts(void)
 		if (p2)
 			*p2 = '\0';
 
-		statmount_opts = sm->str + sm->mnt_opts;
+		if (sm->mask & STATMOUNT_MNT_OPTS)
+			statmount_opts = sm->str + sm->mnt_opts;
+		else
+			statmount_opts = "";
 		if (strcmp(statmount_opts, p) != 0)
 			ksft_test_result_fail(
 				"unexpected mount options: '%s' != '%s'\n",
-- 
2.39.5