Repository: ansible/ansible

Issue:
Ansible module mount cannot remove specific swap devices/files from /etc/fstab
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##### SUMMARY
<!--- Explain the problem briefly -->
Ansible module `mount` cannot remove specific swap devices from `/etc/fstab`.

##### ISSUE TYPE
 - Bug Report

##### COMPONENT NAME
<!--- Insert, BELOW THIS COMMENT, the name of the module, plugin, task or feature.
Do not include extra details here, e.g. "vyos_command" not "the network module vyos_command" or the full path-->
mount

##### ANSIBLE VERSION
<!--- Paste, BELOW THIS COMMENT, verbatim output from "ansible --version" between quotes below -->
```
ansible 2.6.1
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/dist-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.13 (default, Nov 24 2017, 17:33:09) [GCC 6.3.0 20170516]
```

##### CONFIGURATION
<!--- If using Ansible 2.4 or above, paste, BELOW THIS COMMENT, the results of "ansible-config dump --only-changed"
Otherwise, mention any settings you have changed/added/removed in ansible.cfg
(or using the ANSIBLE_* environment variables).-->
N/A

##### OS / ENVIRONMENT
<!--- Mention, BELOW THIS COMMENT, the OS you are running Ansible from, and the OS you are
managing, or say "N/A" for anything that is not platform-specific.
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e.g. if this is a network bug the version of firmware on the network device.-->
CentOS 7.5

##### STEPS TO REPRODUCE
<!--- For bugs, show exactly how to reproduce the problem, using a minimal test-case.
For new features, show how the feature would be used. -->

The following task removes _all_ swap devices because it just matches `path` (should be `none` for swap devices according to fstab(5))

<!--- Paste example playbooks or commands between quotes below -->
```yaml
- name: "Remove swap device(s) from /etc/fstab"
  mount:
    src: '{{ item }}'
    path: none
    fstype: swap
    backup: yes
    state: absent
  with_items: '{{ swapdevs.stdout_lines }}'
  when: 'swapdevs.stdout_lines |length > 0'
```

<!--- You can also paste gist.github.com links for larger files -->

##### EXPECTED RESULTS
<!--- What did you expect to happen when running the steps above? -->
Remove specified device only. To achieve that, the `src` device path should be matched instead of `path`.

##### ACTUAL RESULTS
<!--- What actually happened? If possible run with extra verbosity (-vvvv) -->
`mount` removes all swap device lines in `/etc/fstab`.

<!--- Paste verbatim command output between quotes below -->
```
changed: [n0107] => {
    "changed": true, 
    "dump": "0", 
    "fstab": "/etc/fstab", 
    "fstype": "swap", 
    "invocation": {
        "module_args": {
            "backup": true, 
            "boot": true, 
            "dump": null, 
            "fstab": null, 
            "fstype": "swap", 
            "opts": null, 
            "passno": null, 
            "path": "none", 
            "src": null, 
            "state": "absent"
        }
    }, 
    "name": "none", 
    "opts": "defaults", 
    "passno": "0"
}
```



Discussion:
Might be loosely related to #31437 and #30090.
cc @jtyr
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Resolving patch:
diff --git a/lib/ansible/modules/system/mount.py b/lib/ansible/modules/system/mount.py
--- a/lib/ansible/modules/system/mount.py
+++ b/lib/ansible/modules/system/mount.py
@@ -218,7 +218,13 @@ def set_mount(module, args):
             ) = line.split()
 
         # Check if we found the correct line
-        if ld['name'] != escaped_args['name']:
+        if (
+                ld['name'] != escaped_args['name'] or (
+                    # In the case of swap, check the src instead
+                    'src' in args and
+                    ld['name'] == 'none' and
+                    ld['fstype'] == 'swap' and
+                    ld['src'] != args['src'])):
             to_write.append(line)
 
             continue
@@ -299,7 +305,13 @@ def unset_mount(module, args):
                 ld['passno']
             ) = line.split()
 
-        if ld['name'] != escaped_name:
+        if (
+                ld['name'] != escaped_name or (
+                    # In the case of swap, check the src instead
+                    'src' in args and
+                    ld['name'] == 'none' and
+                    ld['fstype'] == 'swap' and
+                    ld['src'] != args['src'])):
             to_write.append(line)
 
             continue


Test patch:
diff --git a/test/integration/targets/mount/tasks/main.yml b/test/integration/targets/mount/tasks/main.yml
--- a/test/integration/targets/mount/tasks/main.yml
+++ b/test/integration/targets/mount/tasks/main.yml
@@ -148,3 +148,103 @@
       - "unmount_result['changed']"
       - "not dest_stat['stat']['exists']"
   when: ansible_system in ('FreeBSD', 'Linux')
+
+- name: Create fstab record for the first swap file
+  mount:
+    name: none
+    src: /tmp/swap1
+    opts: sw
+    fstype: swap
+    state: present
+  register: swap1_created
+  when: ansible_system in ('Linux')
+
+- name: Try to create fstab record for the first swap file again
+  mount:
+    name: none
+    src: /tmp/swap1
+    opts: sw
+    fstype: swap
+    state: present
+  register: swap1_created_again
+  when: ansible_system in ('Linux')
+
+- name: Check that we created the swap1 record
+  assert:
+    that:
+      - "swap1_created['changed']"
+      - "not swap1_created_again['changed']"
+  when: ansible_system in ('Linux')
+
+- name: Create fstab record for the second swap file
+  mount:
+    name: none
+    src: /tmp/swap2
+    opts: sw
+    fstype: swap
+    state: present
+  register: swap2_created
+  when: ansible_system in ('Linux')
+
+- name: Try to create fstab record for the second swap file again
+  mount:
+    name: none
+    src: /tmp/swap1
+    opts: sw
+    fstype: swap
+    state: present
+  register: swap2_created_again
+  when: ansible_system in ('Linux')
+
+- name: Check that we created the swap2 record
+  assert:
+    that:
+      - "swap2_created['changed']"
+      - "not swap2_created_again['changed']"
+  when: ansible_system in ('Linux')
+
+- name: Remove the fstab record for the first swap file
+  mount:
+    name: none
+    src: /tmp/swap1
+    state: absent
+  register: swap1_removed
+  when: ansible_system in ('Linux')
+
+- name: Try to remove the fstab record for the first swap file again
+  mount:
+    name: none
+    src: /tmp/swap1
+    state: absent
+  register: swap1_removed_again
+  when: ansible_system in ('Linux')
+
+- name: Check that we removed the swap1 record
+  assert:
+    that:
+      - "swap1_removed['changed']"
+      - "not swap1_removed_again['changed']"
+  when: ansible_system in ('Linux')
+
+- name: Remove the fstab record for the second swap file
+  mount:
+    name: none
+    src: /tmp/swap2
+    state: absent
+  register: swap2_removed
+  when: ansible_system in ('Linux')
+
+- name: Try to remove the fstab record for the second swap file again
+  mount:
+    name: none
+    src: /tmp/swap2
+    state: absent
+  register: swap2_removed_again
+  when: ansible_system in ('Linux')
+
+- name: Check that we removed the swap2 record
+  assert:
+    that:
+      - "swap2_removed['changed']"
+      - "not swap2_removed_again['changed']"
+  when: ansible_system in ('Linux')