mount: Add option to backup fstab file (#33734)

This fix adds option to create a backup of fstab file
before making any changes to it.

Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>

lib/ansible/modules/system/mount.py

@@ -84,6 +84,14 @@ options:
     type: bool
     default: 'yes'
     version_added: '2.2'
+  backup:
+    description:
+      - Create a backup file including the timestamp information so you can get
+        the original file back if you somehow clobbered it incorrectly.
+    required: false
+    choices: [ "yes", "no" ]
+    default: "no"
+    version_added: '2.5'
 notes:
   - As of Ansible 2.3, the I(name) option has been changed to I(path) as
     default, but I(name) still works as well.
@@ -125,7 +133,10 @@ from ansible.module_utils.six import iteritems
 from ansible.module_utils._text import to_native
 
 
-def write_fstab(lines, path):
+def write_fstab(module, lines, path):
+    if module.params['backup']:
+        module.backup_local(path)
+
     fs_w = open(path, 'w')
 
     for l in lines:
@@ -236,7 +247,7 @@ def set_mount(module, args):
         changed = True
 
     if changed and not module.check_mode:
-        write_fstab(to_write, args['fstab'])
+        write_fstab(module, to_write, args['fstab'])
 
     return (args['name'], changed)
 
@@ -298,7 +309,7 @@ def unset_mount(module, args):
         changed = True
 
     if changed and not module.check_mode:
-        write_fstab(to_write, args['fstab'])
+        write_fstab(module, to_write, args['fstab'])
 
     return (args['name'], changed)
 
@@ -548,6 +559,7 @@ def main():
             opts=dict(type='str'),
             passno=dict(type='str'),
             src=dict(type='path'),
+            backup=dict(default=False, type='bool'),
             state=dict(type='str', required=True, choices=['absent', 'mounted', 'present', 'unmounted']),
         ),
         supports_check_mode=True,