Allow overlayfs to use O_PATH file descriptors when specifying layers. Userspace must currently use non-O_PATH file desriptors which is often pointless especially if the file descriptors have been created via open_tree(OPEN_TREE_CLONE). This has been a frequent request and came up again in [1]. Link: https://lore.kernel.org/r/fd8f6574-f737-4743-b220-79c815ee1554@xxxxxxxxxxxx [1] Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx> --- Changes in v2: - Unconditionally enable O_PATH file descriptors. - Link to v1: https://lore.kernel.org/r/20250207-work-overlayfs-v1-0-611976e73373@xxxxxxxxxx --- Christian Brauner (2): fs: support O_PATH fds with FSCONFIG_SET_FD selftests/overlayfs: test specifying layers as O_PATH file descriptors fs/autofs/autofs_i.h | 2 + fs/fsopen.c | 2 +- .../filesystems/overlayfs/set_layers_via_fds.c | 65 ++++++++++++++++++++++ 3 files changed, 68 insertions(+), 1 deletion(-) --- base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20250207-work-overlayfs-38fb9156d4c4
