add allow discard option for luks devices (#693)

* add allow discard option for luks devices

* Add allow_discards to perfomance tests

* Fix version for luks devices doc

* Update plugins/modules/luks_device.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* add changelog fragment

* Update changelogs/fragments/693-allow-discards.yaml

Co-authored-by: Felix Fontein <felix@fontein.de>

* added allow_discards to the persistently stored option list

* allow_discards works with not only luks2 containers

* Update plugins/modules/luks_device.py

Co-authored-by: Felix Fontein <felix@fontein.de>

---------

Co-authored-by: Felix Fontein <felix@fontein.de>

tests/integration/targets/luks_device/tasks/tests/performance.yml

@@ -15,6 +15,7 @@
         perf_no_read_workqueue: true
         perf_no_write_workqueue: true
         persistent: true
+        allow_discards: true
         pbkdf:
           iteration_time: 0.1
       check_mode: true
@@ -32,6 +33,7 @@
         perf_no_read_workqueue: true
         perf_no_write_workqueue: true
         persistent: true
+        allow_discards: true
       become: true
       register: create_open
     - name: Create and open (idempotent)
@@ -46,6 +48,7 @@
         perf_no_read_workqueue: true
         perf_no_write_workqueue: true
         persistent: true
+        allow_discards: true
       become: true
       register: create_open_idem
     - name: Create and open (idempotent, check)
@@ -60,6 +63,7 @@
         perf_no_read_workqueue: true
         perf_no_write_workqueue: true
         persistent: true
+        allow_discards: true
       check_mode: true
       become: true
       register: create_open_idem_check
@@ -80,6 +84,7 @@
           - "'no-write-workqueue' in luks_header.stdout"
           - "'same-cpu-crypt' in luks_header.stdout"
           - "'submit-from-crypt-cpus' in luks_header.stdout"
+          - "'allow-discards' in luks_header.stdout"
 
     - name: Dump device mapper table
       command: "dmsetup table {{ create_open.name }}"
@@ -91,6 +96,7 @@
           - "'no_write_workqueue' in dm_table.stdout"
           - "'same_cpu_crypt' in dm_table.stdout"
           - "'submit_from_crypt_cpus' in dm_table.stdout"
+          - "'allow_discards' in dm_table.stdout"
 
     - name: Closed and Removed
       luks_device: