Fix swap on linux+btrfs

roles/fri_base/tasks/main_lin.yml

@@ -1,6 +1,55 @@
 - name: Enable multiarch
   command: dpkg --add-architecture i386
 
+- name: Create swap btrfs subvolume
+  command: btrfs subvolume create /swap
+  ignore_errors: True
+
+- name: Create swap directory if it does not exist
+  file:
+    path: /swap
+    state: directory
+
+- name: Create btrfs swap
+  command: btrfs filesystem mkswapfile --size 4g /swap/swap.img
+  ignore_errors: True
+
+- name: Create swap image if it does not exist
+  shell: fallocate -l 4G /swap/swap.img && mkswap /swap/swap.img
+  args:
+    creates: /swap/swap.img
+  ignore_errors: True
+
+- name: Change swap file permissions
+  file: path="/swap/swap.img"
+        owner=root
+        group=root
+        mode=0600
+
+- name: Write swap entry in fstab
+  mount: name=none
+         src=/swap/swap.img
+         fstype=swap
+         opts=sw
+         passno=0
+         dump=0
+         state=present
+
+- name: Activate swap
+  command: "swapon /swap/swap.img"
+  ignore_errors: True
+
+- name: Make sure default swap entry does not exist
+  mount:
+    path: none
+    src: /swap.img
+    fstype: swap
+    state: absent
+
+- name: Make sure default swap is not used
+  command: swapoff /swap/swap.img
+  ignore_errors: True
+
 - name: Install generally useful packages
   apt:
     name: