[PATCH v8 0/1] selftests/landlock: fix fs_tests when overlayfs

[jeffxu@chromium.org]

From: Jeff Xu <jeffxu@google.com>

Overlayfs can be disabled in kernel config, causing related tests to
fail. Adding a check for overlayfs’s supportability at runtime,
so we can call SKIP() when needed.

Note: 
Below comments are raised during V7 discussion:

Currently SKIP() is applied to FIXTURE_SETUP, FIXTURE_TEARDOWN,
TEST_F_FORK, this is because SKIP() apply within the function 
scope, not the testcase.

We would like test infra to have a dedicated environment 
check hook (FIXTURE_ENV_CHECK) in test infra, called before 
FIXTURE_SETUP(). If the environment check fails, the remaining 
of the test will be skipped. The benefit of these are two:
1> if env check pass, in theory, the test should pass.
2> if env check fail, no need to call setup, so no need to cleanup
resource.

v8:
style change, no logic change.

v7:
https://lore.kernel.org/all/20221229211446.3154454-1-jeffxu@google.com/
Fix bug in supports_overlayfs().
Manual test with kernel with and without overlayfs.

v6: https://lore.kernel.org/all/20221229201215.3006512-1-jeffxu@google.com/
In v4, the SKIP() was applied at FIXTURE_SETUP() after mount() fail,
however, FIXTURE_TEARDOWN() will fail. It might be complicated 
for test infra or testcase itself to have cleanup code handing the
success/failure of steps in SETUP().

This patch changes the approach, it calls supports_overlay() and SKIP()
at the beginning of FIXTURE_SETUP(), FIX_TEARDOWN(), TEST_F_FORK().
Because no modification of system is done by the test, cleanup is not 
needed.

v4:
https://lore.kernel.org/all/20220823010216.2653012-1-jeffxu@google.com/


Jeff Xu (1):
  selftests/landlock: skip overlayfs test when not support

 tools/testing/selftests/landlock/fs_test.c | 48 ++++++++++++++++++++++
 1 file changed, 48 insertions(+)


base-commit: 963a70bee5880640d0fd83ed29dc1e7ec0d2bd4a
-- 
2.39.0.314.g84b9a713c41-goog