[PATCH v9 4/6] selftests/liveupdate: add test case for LUO_SESSION_MAGIC

luca.boccassi
2026-04-20T14:17:51Z

Verify that fstat works as expected after the switch from anon_inode
to the new magic number.

Signed-off-by: Luca Boccassi <luca.boccassi@gmail.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
.../testing/selftests/liveupdate/liveupdate.c | 40 +++++++++++++++++++
1 file changed, 40 insertions(+)

diff --git a/tools/testing/selftests/liveupdate/liveupdate.c b/tools/testing/selftests/liveupdate/liveupdate.c
index f0a8e600c154..5e99af0cc6e9 100644
--- a/tools/testing/selftests/liveupdate/liveupdate.c
+++ b/tools/testing/selftests/liveupdate/liveupdate.c
@@ -22,9 +22,12 @@
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/vfs.h>
#include <unistd.h>

#include <linux/liveupdate.h>
+#include <linux/magic.h>

#include "../kselftest.h"
#include "../kselftest_harness.h"
@@ -387,4 +390,41 @@ TEST_F(liveupdate_device, create_session_empty_name)
EXPECT_EQ(session_fd, -EINVAL);
}

+/*
+ * Test Case: Session fstat
+ *
+ * Verifies that fstatfs() on a session file descriptor reports the
+ * LUO_SESSION_MAGIC filesystem type, and that fstat() returns consistent
+ * inode numbers across different sessions (shared singleton inode).
+ */
+TEST_F(liveupdate_device, session_fstat)
+{
+ int session_fd1, session_fd2;
+ struct stat st1, st2;
+ struct statfs sfs;
+
+ self->fd1 = open(LIVEUPDATE_DEV, O_RDWR);
+ if (self->fd1 < 0 && errno == ENOENT)
+ SKIP(return, "%s does not exist", LIVEUPDATE_DEV);
+ ASSERT_GE(self->fd1, 0);
+
+ session_fd1 = create_session(self->fd1, "fstat-session-1");
+ ASSERT_GE(session_fd1, 0);
+
+ session_fd2 = create_session(self->fd1, "fstat-session-2");
+ ASSERT_GE(session_fd2, 0);
+
+ /* Verify the filesystem type is LUO_SESSION_MAGIC */
+ ASSERT_EQ(fstatfs(session_fd1, &sfs), 0);
+ EXPECT_EQ(sfs.f_type, LUO_SESSION_MAGIC);
+
+ /* Verify both sessions share the same inode number */
+ ASSERT_EQ(fstat(session_fd1, &st1), 0);
+ ASSERT_EQ(fstat(session_fd2, &st2), 0);
+ EXPECT_EQ(st1.st_ino, st2.st_ino);
+
+ ASSERT_EQ(close(session_fd1), 0);
+ ASSERT_EQ(close(session_fd2), 0);
+}
+
TEST_HARNESS_MAIN
--
2.47.3