Canceling backup restore displays confirmation message, but restore is never actually cancelled

[heinrich-ulbricht]

The problem you're addressing (if any)
Currently there are multiple issues regarding restoring large backups (in my case ~650 GB), e.g. #4791 and #3230. While trying to work around those I noticed another issue: it is not possible to cancel a running restore operation via the UI.

Choosing to cancel the restore operation outputs a red message that the operation is going to be canceled - but it never is. Looking at the task manager I see that the process tar -xiv [...] (-> restore.py) continues to run, which is responsible for extracting chunk files to my temporary directory. Apparently this process continues to run until all files are extracted - which in my case are ~6000. This leads to the situation described in #4791: the temp dir fills up, then the restore operation fails.

Describe the solution you'd like
I'd like the restore operation to stop immediately after choosing the cancel button. No need to continue extracting files.

Where is the value to a user, and who might that user be?
The value is a good user experience for every user restoring from larger backups.

Describe alternatives you've considered
Well. I used the task manager to kill some of the tar processes which makes the restore fail and thus end.

Additional context
This issue might be related to the "tar method" only. This method is used when restoring from a backup accessible to dom0. (So the backup is NOT restored from an AppVM.)

Related, non-duplicate issues

#4791
#3230

[github-actions]

This issue is being closed because:

• This issue is on the "Release 4.0 updates" milestone.
• Qubes OS 4.0 reached EOL (end-of-life) over one year ago.
• There has not been any activity on this issue in over one year.

If anyone believes that this issue should be reopened and reassigned to an active milestone, please leave a brief comment.
(For example, if a bug still affects Qubes OS 4.1, then the comment "Affects 4.1" will suffice.)