Backup: verification process continues running after failure

[andrewdavidwong]

In Qubes Manager, attempt to restore a backup tarball with the "verify only" option. It might fail with this error message (related: #1577, #1471):

    ERROR: ERROR: invalid hmac for file /var/tmp/restore_[...]:
    [...]
    Is the passphrase correct?
    Partially restored files left in /var/tmp/restore_*, investigate them and/or clean them up

The progress bar quickly finishes, the user can then acknowledge the message, and the window will close. However, it seems that the process continues running for some time in the background, as evidenced by high CPU usage and the whole system slowing to a crawl (see #1288). In general, if a status bar visually depicts the progress of some process to the user, it should do so truthfully, and closing the window associated with that process should coincide with that process ending (see #1479).

[andrewdavidwong]

If some sort of cleanup process must run when (or after) the verification fails, then it would be good to display an appropriate message and progress bar (if possible) to the user. For example:

Cleaning up failed restore attempt. Please wait.
[=================>                           ]

[andrewdavidwong]

If some sort of cleanup process must run when (or after) the verification fails, then it would be good to display an appropriate message and progress bar (if possible) to the user. For example:

Cleaning up failed restore attempt. Please wait.
[=================>                           ]

[marmarek]

There is a code to kill background tasks when the operation is canceled (https://github.com/QubesOS/qubes-core-admin/blob/master/core/backup.py#L109-L114). Probably the same should be done on failure.

[marmarek]

There is a code to kill background tasks when the operation is canceled (https://github.com/QubesOS/qubes-core-admin/blob/master/core/backup.py#L109-L114). Probably the same should be done on failure.