From 3423bbc17f5521de8ff80e76d91ce13657b1cea2 Mon Sep 17 00:00:00 2001
From: Kairui Song <kasong@redhat.com>
Date: Thu, 8 Apr 2021 01:36:49 +0800
Subject: [PATCH] kdump-lib.sh: introduce a helper to get underlying crypt
 device

Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Pingfan Liu <piliu@redhat.com>
---
 kdump-lib.sh | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/kdump-lib.sh b/kdump-lib.sh
index 4dcd134..ecb2721 100755
--- a/kdump-lib.sh
+++ b/kdump-lib.sh
@@ -958,3 +958,20 @@ kdump_get_arch_recommend_size()
     echo $result
     return 0
 }
+
+# Print all underlying crypt devices of a block device
+# print nothing if device is not on top of a crypt device
+# $1: the block device to be checked in maj:min format
+get_luks_crypt_dev()
+{
+    [[ -b /dev/block/$1 ]] || return 1
+
+    local _type=$(eval "$(blkid -u filesystem,crypto -o export -- /dev/block/$1); echo \$TYPE")
+    [[ $_type == "crypto_LUKS" ]] && echo $1
+
+    for _x in /sys/dev/block/$1/slaves/*; do
+        [[ -f $_x/dev ]] || continue
+        [[ $_x/subsystem -ef /sys/class/block ]] || continue
+        get_luks_crypt_dev "$(< "$_x/dev")"
+    done
+}