tests/kola: add soft-reboot test for LUKS root encryption

Validate that soft-reboot works correctly when the root filesystem
is on a LUKS device. This exercises the x-initrd.attach crypttab
option added in coreos/ignition#2219.

Author: prestist

tests/kola/root-reprovision/luks/soft-reboot/config.ign

@@ -0,0 +1 @@
+../config.ign

tests/kola/root-reprovision/luks/soft-reboot/data

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+../data

tests/kola/root-reprovision/luks/soft-reboot/test.sh

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+#!/bin/bash
+## kola:
+##   # This test reprovisions the rootfs.
+##   tags: "platform-independent reprovision"
+##   # Root reprovisioning requires at least 4GiB of memory.
+##   minMemory: 4096
+##   # A TPM backend device is not available on s390x to support TPM.
+##   architectures: "! s390x"
+##   # This test includes a lot of disk I/O and needs a higher
+##   # timeout value than the default.
+##   timeoutMin: 15
+##   description: Verify that soft-reboot works with LUKS root encryption.
+
+set -xeuo pipefail
+
+# shellcheck disable=SC1091
+. "$KOLA_EXT_DATA/commonlib.sh"
+
+case "${AUTOPKGTEST_REBOOT_MARK:-}" in
+  "")
+      srcdev=$(findmnt -nvr /sysroot -o SOURCE)
+      [[ ${srcdev} == /dev/mapper/myluksdev ]]
+
+      blktype=$(lsblk -o TYPE "${srcdev}" --noheadings)
+      [[ ${blktype} == crypt ]]
+      ok "root is on LUKS device"
+
+      /tmp/autopkgtest-soft-reboot soft-rebooted
+      ;;
+
+  soft-rebooted)
+      srcdev=$(findmnt -nvr /sysroot -o SOURCE)
+      [[ ${srcdev} == /dev/mapper/myluksdev ]]
+
+      blktype=$(lsblk -o TYPE "${srcdev}" --noheadings)
+      [[ ${blktype} == crypt ]]
+      ok "soft-reboot successful with LUKS root"
+      ;;
+
+  *) fatal "unexpected mark: ${AUTOPKGTEST_REBOOT_MARK}";;
+esac