From 4fd0aea1ea7a64801caa5f0b149004f418270554 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Fri, 21 Feb 2025 14:13:11 +0100 Subject: [PATCH] selftests: third test for mounting detached mounts onto detached mounts Add a test to verify that detached mounts behave correctly. Link: https://lore.kernel.org/r/20250221-brauner-open_tree-v1-12-dbcfcb98c676@kernel.org Signed-off-by: Christian Brauner --- .../mount_setattr/mount_setattr_test.c | 31 +++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/tools/testing/selftests/mount_setattr/mount_setattr_test.c b/tools/testing/selftests/mount_setattr/mount_setattr_test.c index 082fdf19a9be..66eed84c6a01 100644 --- a/tools/testing/selftests/mount_setattr/mount_setattr_test.c +++ b/tools/testing/selftests/mount_setattr/mount_setattr_test.c @@ -1878,4 +1878,35 @@ TEST_F(mount_setattr, mount_detached_mount_on_detached_mount_and_attach) EXPECT_EQ(close(fd_tree_subdir), 0); } +TEST_F(mount_setattr, move_mount_detached_fail) +{ + int fd_tree_base = -EBADF, fd_tree_subdir = -EBADF; + struct statx stx; + + fd_tree_base = sys_open_tree(-EBADF, "/mnt", + AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW | + OPEN_TREE_CLOEXEC | OPEN_TREE_CLONE); + ASSERT_GE(fd_tree_base, 0); + + /* Attach the mount to the caller's mount namespace. */ + ASSERT_EQ(move_mount(fd_tree_base, "", -EBADF, "/tmp/target1", MOVE_MOUNT_F_EMPTY_PATH), 0); + + ASSERT_EQ(statx(fd_tree_base, "A", 0, 0, &stx), 0); + ASSERT_FALSE(stx.stx_attributes & STATX_ATTR_MOUNT_ROOT); + + fd_tree_subdir = sys_open_tree(-EBADF, "/tmp/B", + AT_NO_AUTOMOUNT | AT_SYMLINK_NOFOLLOW | + OPEN_TREE_CLOEXEC | OPEN_TREE_CLONE); + ASSERT_GE(fd_tree_subdir, 0); + ASSERT_EQ(statx(fd_tree_subdir, "BB", 0, 0, &stx), 0); + ASSERT_FALSE(stx.stx_attributes & STATX_ATTR_MOUNT_ROOT); + + /* Not allowed to move an attached mount to a detached mount. */ + ASSERT_NE(move_mount(fd_tree_base, "", fd_tree_subdir, "", MOVE_MOUNT_F_EMPTY_PATH | MOVE_MOUNT_T_EMPTY_PATH), 0); + ASSERT_EQ(errno, EINVAL); + + EXPECT_EQ(close(fd_tree_base), 0); + EXPECT_EQ(close(fd_tree_subdir), 0); +} + TEST_HARNESS_MAIN -- 2.25.1