kernel/linux.git/tools/testing/selftests/filesystems/utils.h, branch linux-7.1.y

selftests/filesystems: add tests for empty mount namespaces

2026-03-12T12:33:55+00:00

Add a test suite for the UNSHARE_EMPTY_MNTNS and CLONE_EMPTY_MNTNS flags exercising the empty mount namespace functionality through the kselftest harness. The tests cover: - basic functionality: unshare succeeds, exactly one mount exists in the new namespace, root and cwd point to the same mount - flag interactions: UNSHARE_EMPTY_MNTNS works standalone without explicit CLONE_NEWNS, combines correctly with CLONE_NEWUSER and other namespace flags (CLONE_NEWUTS, CLONE_NEWIPC) - edge cases: EPERM without capabilities, works from a user namespace, many source mounts still result in one mount, cwd on a different mount gets reset to root - error paths: invalid flags return EINVAL - regression: plain CLONE_NEWNS still copies the full mount tree, other namespace unshares are unaffected - mount properties: the root mount has the expected statmount properties, is its own parent, and is the only entry returned by listmount - repeated unshare: consecutive UNSHARE_EMPTY_MNTNS calls each produce a new namespace with a distinct mount ID - overmount workflow: verifies the intended usage pattern of creating an empty mount namespace with a nullfs root and then mounting tmpfs over it to build a writable filesystem from scratch Link: https://patch.msgid.link/20260306-work-empty-mntns-consolidated-v1-2-6eb30529bbb0@kernel.org Signed-off-by: Christian Brauner

selftests/open_tree: add OPEN_TREE_NAMESPACE tests

2026-01-16T18:21:40+00:00

Add tests for OPEN_TREE_NAMESPACE. Link: https://patch.msgid.link/20251229-work-empty-namespace-v1-2-bfb24c7b061f@kernel.org Tested-by: Jeff Layton Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner

selftests/filesystems: create setup_userns() helper

2025-05-12T09:40:13+00:00

Add helper to utils.c and use it in statmount userns tests. Reviewed-by: John Hubbard Signed-off-by: Amir Goldstein Link: https://lore.kernel.org/20250509133240.529330-8-amir73il@gmail.com Reviewed-by: Christian Brauner Signed-off-by: Christian Brauner

selftests/filesystems: create get_unique_mnt_id() helper

2025-05-12T09:40:12+00:00

Add helper to utils.c and use it in mount-notify and statmount tests. Linking with utils.c drags in a dependecy with libcap, so add it to the Makefile of the tests. Reviewed-by: John Hubbard Signed-off-by: Amir Goldstein Link: https://lore.kernel.org/20250509133240.529330-7-amir73il@gmail.com Reviewed-by: Christian Brauner Signed-off-by: Christian Brauner

selftests/ovl: add third selftest for "override_creds"

2025-02-19T13:32:12+00:00

Add a simple test to verify that the new "override_creds" option works. Link: https://lore.kernel.org/r/20250219-work-overlayfs-v3-4-46af55e4ceda@kernel.org Reviewed-by: Amir Goldstein Signed-off-by: Christian Brauner

selftests/filesystems: add utils.{c,h}

2025-02-19T13:32:12+00:00

Add a new set of helpers that will be used in follow-up patches. Signed-off-by: Christian Brauner