On Tue, Oct 15, 2024 at 1:15 PM Christian Brauner <brauner@xxxxxxxxxx> wrote:
>
> Verify that we can actually specify 500 lower layers and fail at the
> 501st one.
>
> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx>
> ---
> Just noticed that we didn't have that and we'd already regressed that
> once and now that I've done new selftests already just add a selftest
> for this on top.
Thanks!
I guess this is going to be added to your vfs.ovl branch, so
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> .../overlayfs/set_layers_via_fds.c | 65 +++++++++++++++++++
> 1 file changed, 65 insertions(+)
>
> diff --git a/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c b/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
> index 301fb5c02852..1d0ae785a667 100644
> --- a/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
> +++ b/tools/testing/selftests/filesystems/overlayfs/set_layers_via_fds.c
> @@ -149,4 +149,69 @@ TEST_F(set_layers_via_fds, set_layers_via_fds)
> ASSERT_EQ(fclose(f_mountinfo), 0);
> }
>
> +TEST_F(set_layers_via_fds, set_500_layers_via_fds)
> +{
> + int fd_context, fd_tmpfs, fd_overlay, fd_work, fd_upper, fd_lower;
> + int layer_fds[500] = { [0 ... 499] = -EBADF };
> +
> + ASSERT_EQ(unshare(CLONE_NEWNS), 0);
> + ASSERT_EQ(sys_mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL), 0);
> +
> + fd_context = sys_fsopen("tmpfs", 0);
> + ASSERT_GE(fd_context, 0);
> +
> + ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0), 0);
> + fd_tmpfs = sys_fsmount(fd_context, 0, 0);
> + ASSERT_GE(fd_tmpfs, 0);
> + ASSERT_EQ(close(fd_context), 0);
> +
> + for (int i = 0; i < ARRAY_SIZE(layer_fds); i++) {
> + char path[100];
> +
> + sprintf(path, "l%d", i);
> + ASSERT_EQ(mkdirat(fd_tmpfs, path, 0755), 0);
> + layer_fds[i] = openat(fd_tmpfs, path, O_DIRECTORY);
> + ASSERT_GE(layer_fds[i], 0);
> + }
> +
> + ASSERT_EQ(mkdirat(fd_tmpfs, "w", 0755), 0);
> + fd_work = openat(fd_tmpfs, "w", O_DIRECTORY);
> + ASSERT_GE(fd_work, 0);
> +
> + ASSERT_EQ(mkdirat(fd_tmpfs, "u", 0755), 0);
> + fd_upper = openat(fd_tmpfs, "u", O_DIRECTORY);
> + ASSERT_GE(fd_upper, 0);
> +
> + ASSERT_EQ(mkdirat(fd_tmpfs, "l501", 0755), 0);
> + fd_lower = openat(fd_tmpfs, "l501", O_DIRECTORY);
> + ASSERT_GE(fd_lower, 0);
> +
> + ASSERT_EQ(sys_move_mount(fd_tmpfs, "", -EBADF, "/tmp", MOVE_MOUNT_F_EMPTY_PATH), 0);
> + ASSERT_EQ(close(fd_tmpfs), 0);
> +
> + fd_context = sys_fsopen("overlay", 0);
> + ASSERT_GE(fd_context, 0);
> +
> + ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "workdir", NULL, fd_work), 0);
> + ASSERT_EQ(close(fd_work), 0);
> +
> + ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "upperdir", NULL, fd_upper), 0);
> + ASSERT_EQ(close(fd_upper), 0);
> +
> + for (int i = 0; i < ARRAY_SIZE(layer_fds); i++) {
> + ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, layer_fds[i]), 0);
> + ASSERT_EQ(close(layer_fds[i]), 0);
> + }
> +
> + ASSERT_NE(sys_fsconfig(fd_context, FSCONFIG_SET_FD, "lowerdir+", NULL, fd_lower), 0);
> + ASSERT_EQ(close(fd_lower), 0);
> +
> + ASSERT_EQ(sys_fsconfig(fd_context, FSCONFIG_CMD_CREATE, NULL, NULL, 0), 0);
> +
> + fd_overlay = sys_fsmount(fd_context, 0, 0);
> + ASSERT_GE(fd_overlay, 0);
> + ASSERT_EQ(close(fd_context), 0);
> + ASSERT_EQ(close(fd_overlay), 0);
> +}
> +
> TEST_HARNESS_MAIN
> --
> 2.45.2
>
