Bug 1427187 - Rolling back a checkpoint without any changes still reconnects all devices
Summary: Rolling back a checkpoint without any changes still reconnects all devices
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: NetworkManager
Version: 25
Hardware: Unspecified
OS: Unspecified
unspecified
low
Target Milestone: ---
Assignee: Beniamino Galvani
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-02-27 14:42 UTC by Marius Vollmer
Modified: 2017-12-12 10:06 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2017-12-12 10:06:51 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)
[PATCH] checkpoint: reactivate/update connections only if necessary on rollback (7.44 KB, patch)
2017-03-05 11:01 UTC, Beniamino Galvani
no flags Details | Diff
[PATCH v2] checkpoint: reactivate/update connections only if necessary on rollback (8.93 KB, patch)
2017-03-06 09:20 UTC, Beniamino Galvani
no flags Details | Diff

Description Marius Vollmer 2017-02-27 14:42:30 UTC
Description of problem:

When creating a checkpoint and then immediately rolling it back, all devices are reconnected although no actual changes need to be rolled back.

Cockpit rolls back a checkpoint when a configuration change has failed, and to make matters worse, Cockpit always takes checkpoints over _all_ devices, because why not.

This mostly doesn't matter, but because of the asynchronicity of everything, weird things are happening sometimes.

Version-Release number of selected component (if applicable):
NetworkManager-1.4.4-3.fc25.x86_64

How reproducible:
Always.

Steps to Reproduce:
1. gdbus call -y -d org.freedesktop.NetworkManager -o /org/freedesktop/NetworkManager -m org.freedesktop.NetworkManager.CheckpointCreate '[]' 0 0
(objectpath '/org/freedesktop/NetworkManager/Checkpoint/1',)
2. gdbus call -y -d org.freedesktop.NetworkManager -o /org/freedesktop/NetworkManager -m org.freedesktop.NetworkManager.CheckpointRollback /org/freedesktop/NetworkManager/Checkpoint/1


Actual results:
All interfaces are reconnected.

Expected results:
Nothing happens except the destruction of the checkpoint.

Additional info:
Cockpit should really make checkpoints just for the interfaces that are being changed.

Comment 1 Beniamino Galvani 2017-03-05 11:01:54 UTC
Created attachment 1260052 [details]
[PATCH] checkpoint: reactivate/update connections only if necessary on rollback

The attached patch avoids unnecessary operations (update and activate) on connections during a rollback.

Comment 2 Thomas Haller 2017-03-06 07:40:59 UTC
/* ... or if the applied connection differs */
+    if (!nm_connection_compare (dev_checkpoint->applied_connection,
+                                nm_active_connection_get_applied_connection (active),
+                                NM_SETTING_COMPARE_FLAG_EXACT)) {

you could instead compare the version-id of the active-connection.
The difference is, your check tests whether the applied-connection differs,
the version-id tests whether the active-connection was deactivated/reapplied in the meantime. That latter test might make more sense in this context(??).

_LOGT ("rollback: connection is active");

these log statements could mention the connection they are talking about... otherwise, the logfile may contain several "connection is active" lines, but it's a bit confusing. 

indention in
+                        _LOGD ("rollback: updating connection %s",
+                                nm_setting


otherwise, lgtm

Comment 3 Marius Vollmer 2017-03-06 08:44:10 UTC
Fyi, Cockpit is now much better behaved: https://github.com/cockpit-project/cockpit/pull/5986

Comment 4 Beniamino Galvani 2017-03-06 09:20:38 UTC
Created attachment 1260321 [details]
[PATCH v2] checkpoint: reactivate/update connections only if necessary on rollback

(In reply to Thomas Haller from comment #2)
> /* ... or if the applied connection differs */
> +    if (!nm_connection_compare (dev_checkpoint->applied_connection,
> +                                nm_active_connection_get_applied_connection
> (active),
> +                                NM_SETTING_COMPARE_FLAG_EXACT)) {
> 
> you could instead compare the version-id of the active-connection.
> The difference is, your check tests whether the applied-connection differs,
> the version-id tests whether the active-connection was deactivated/reapplied
> in the meantime. That latter test might make more sense in this context(??).

Both checks are fine, but comparing the version id is simpler and faster.


> _LOGT ("rollback: connection is active");
> 
> these log statements could mention the connection they are talking about...
> otherwise, the logfile may contain several "connection is active" lines, but
> it's a bit confusing. 
> 
> indention in
> +                        _LOGD ("rollback: updating connection %s",
> +                                nm_setting
> 

Fixed.

Comment 5 Thomas Haller 2017-03-06 10:56:15 UTC
lgtm now

Comment 7 Fedora End Of Life 2017-11-16 19:22:04 UTC
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Comment 8 Fedora End Of Life 2017-12-12 10:06:51 UTC
Fedora 25 changed to end-of-life (EOL) status on 2017-12-12. Fedora 25 is
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