fix: correctly select root disk partition

ansible/files/admin_api_scripts/grow_fs.sh

@@ -9,15 +9,32 @@ if pgrep resizefs; then
     exit 1
 fi
 
+# Parses the output of lsblk to get the root partition number
+# Example output:
+# NAME        MOUNTPOINT
+# nvme0n1
+# ├─nvme0n1p1 /boot
+# └─nvme0n1p3 /
+# nvme1n1     /data
+#
+# Resulting in:
+# └─nvme0n1p3 / -> nvme0n1p3 -> 3
+ROOT_PARTITION_NUMBER=$(lsblk -no NAME,MOUNTPOINT | grep ' /$' | awk '{print $1;}' | sed 's/.*nvme[0-9]n[0-9]p//g')
+
+if ! [[ "$ROOT_PARTITION_NUMBER" =~ ^[0-9]+$ ]]; then
+  echo "Error: ROOT_PARTITION_NUMBER is not a valid number: $ROOT_PARTITION_NUMBER"
+  exit 1
+fi
+
 if [ -b /dev/nvme1n1 ] ; then
     if [[ "${VOLUME_TYPE}" == "data" ]]; then
         resize2fs /dev/nvme1n1
 
     elif [[ "${VOLUME_TYPE}" == "root" ]] ; then
         PLACEHOLDER_FL=/home/ubuntu/50M_PLACEHOLDER
         rm -f "${PLACEHOLDER_FL}" || true
-        growpart /dev/nvme0n1 2
-        resize2fs /dev/nvme0n1p2
+        growpart /dev/nvme0n1 "${ROOT_PARTITION_NUMBER}"
+        resize2fs "/dev/nvme0n1p${ROOT_PARTITION_NUMBER}"
         if [[ ! -f "${PLACEHOLDER_FL}" ]] ; then
             fallocate -l50M "${PLACEHOLDER_FL}"
         fi
@@ -26,7 +43,7 @@ if [ -b /dev/nvme1n1 ] ; then
         exit 1
     fi
 else
-    growpart /dev/nvme0n1 2
-    resize2fs /dev/nvme0n1p2
+    growpart /dev/nvme0n1 "${ROOT_PARTITION_NUMBER}"
+    resize2fs "/dev/nvme0n1p${ROOT_PARTITION_NUMBER}"
 fi
 echo "Done resizing disk"