drush up drupal fails on _drush_recursive_copy - drupal

Question

I am not able to upgrade to drupal 8.6.2 using drush 8.1.17. Unfortunately, drush does not provide the reason behind its failure. I have no clue of what do do next, and even how to debug it further. Any help is appreciated, thanks in advance.
It follows an excerpt of the command $ drush --debug up drupal, you can find the (almost) complete log here (I only removed the untar output to have a smaller file such that can be pasted on pastebin)
Calling chdir(/var/www/html) [94.7 sec, 14.02 MB] [debug]
Calling is_readable(/tmp/drush_tmp_1539963315_5bc9f9b34e37c/drupal-8.6.2) [94.7 sec, 14.02 MB] [debug]
Calling is_writable(/var/www/html) [94.7 sec, 14.02 MB] [debug]
Calling rename(/tmp/drush_tmp_1539963315_5bc9f9b34e37c/drupal-8.6.2, /var/www/html/drupal-8.6.2) [94.7 sec, 14.02 MB] [debug]
Calling _drush_recursive_copy(/tmp/drush_tmp_1539963315_5bc9f9b34e37c/drupal-8.6.2, /var/www/html/drupal-8.6.2) [94.7 sec, 14.02 MB] [debug]
Unable to copy /tmp/drush_tmp_1539963315_5bc9f9b34e37c/drupal-8.6.2 to /var/www/html/drupal-8.6.2. [116.8 sec, 14.02 MB] [error]
Unable to move /tmp/drush_tmp_1539963315_5bc9f9b34e37c/drupal-8.6.2 to /var/www/html/drupal-8.6.2. [116.8 sec, 14.02 MB] [error]
Updating project drupal failed. Attempting to roll back to previously installed version. [116.8 sec, 14.02 MB] [error]
Returned from hook drush_pm_updatecode [116.8 sec, 13.92 MB] [debug]
Rolling back update of Drupal core code ... [116.8 sec, 13.92 MB] [notice]
Verifying signature for svn version control engine. [116.8 sec, 13.92 MB] [debug]
Executing: svn info drupal-8.6.2
sh: 1: svn: not found
Verifying signature for bzr version control engine. [117.1 sec, 10.88 MB] [debug]
Executing: bzr root drupal-8.6.2
sh: 1: bzr: not found
Calling drush_delete_dir(/var/www/html/drupal-8.6.2, 1) [117.2 sec, 10.88 MB] [debug]
Calling is_readable(/var/www/drush-backups/the_site_com/20181019153440/drupal) [121.8 sec, 10.88 MB] [debug]
Calling is_writable(/var/www/html) [121.8 sec, 10.88 MB] [debug]
Calling rename(/var/www/drush-backups/the_site_com/20181019153440/drupal, /var/www/html/drupal-8.6.2) [121.8 sec, 10.88 MB] [debug]
Backups were restored successfully. [121.8 sec, 10.88 MB] [ok]
A couple of info that might be useful:
root#host:/var/www/html# su www-data -s /bin/bash -c 'drush --version'
Drush Version : 8.1.17
root#host:/var/www/html# su www-data -s /bin/bash -c 'drush core-status'
Drupal version : 8.5.3
Site URI : http://default
Database driver : mysql
Database hostname : the-database-hostname
Database port :
Database username : the-database-username
Database name : the-database-name
Database : Connected
Drupal bootstrap : Successful
Drupal user :
Default theme : mytheme
Administration theme : seven
PHP configuration : /usr/local/etc/php/php.ini
PHP OS : Linux
Drush script : /usr/local/bin/drush
Drush version : 8.1.17
Drush temp directory : /tmp
Drush configuration :
Drush alias files :
Install profile : standard
Drupal root : /var/www/html
Drupal Settings File : sites/default/settings.php
Site path : sites/default
File directory path : sites/default/files
Temporary file directory path : /tmp
Sync config path : sites/default/files/config_xeVhGsWgDSMcUJNlA97zQiNNekC93e2MhX5aEtO5UcOtKQnwq7fjEB9K6Bk15kj53APj6h8Ibg/sync

Answer 1

That's probably very easy to explain.
Drupal 8 now requires Drush 9.
See the chart on http://docs.drush.org/en/master/install. D8.3- means with Drush 8 your Drupal can not be greater than or equal to 8.3.
I don't know how far you already got with your project. But you may consider to restart with drupal-composer/drupal-project which already always will have the right Drush version as local dependency on board. And it will also tell you to not update Drupal with Drush anymore. Do that with Composer instead.