ignition-ostree-transposefs: check if we need to use the root set by …

…the multipath-generator

When enabling multipath the root partition label is set by the  multipath-generator
this change makes sure to use the multipath one if needed.
This was reported via: https://issues.redhat.com/browse/OCPBUGS-16157

overlay.d/05core/usr/lib/dracut/modules.d/40ignition-ostree/ignition-ostree-transposefs.sh

@@ -10,7 +10,6 @@ prep_typeguid=9e1a2d38-c612-4316-aa26-8b49521e5a8b
 # out a way to ask Ignition directly whether there's a filesystem with label
 # "root" being set up.
 ignition_cfg=/run/ignition.json
-root_part=/dev/disk/by-label/root
 boot_part=/dev/disk/by-label/boot
 esp_part=/dev/disk/by-label/EFI-SYSTEM
 bios_part=/dev/disk/by-partlabel/BIOS-BOOT
@@ -139,13 +138,15 @@ should_autosave_rootfs() {
         return
     fi
     local agcount
-    eval $(xfs_info "${root_part}" | grep -o 'agcount=[0-9]*')
+    xfsinfo=$(xfs_info "${root_part}")
+    agcount=$(echo "$xfsinfo" | grep -o 'agcount=[0-9]*' | tr -dc '0-9')
     # Semi-arbitrarily chosen: this is roughly ~64G currently (based on initial
     # ag sizing at build time) which seems like a good rootfs size at which to
     # discriminate between "throwaway/short-lived systems" and "long-running
     # workload systems". It's not like XFS performance is way worse at 128.
+    echo "Filesystem agcount is $agcount"
     if [ "$agcount" -lt 128 ]; then
-        echo "Filesystem agcount is $agcount; skipping" >&2
+        echo "Filesystem agcount < 128; skipping" >&2
         echo 0
         return
     fi
@@ -205,6 +206,13 @@ check_and_set_secex_config() {
 # info from config, so just check cached one and reset to secex.ign now
 check_and_set_secex_config
 
+root_part=$(karg root)
+if test -z "${root_part}"; then
+    root_part=/dev/disk/by-label/root
+fi
+echo "root_part is: ${root_part}"
+
+
 case "${1:-}" in
     detect)
         # Mounts are not in a private namespace so we can mount ${saved_data}