upgrade from 3.1.15 to 3.5.4 throws "Invalid permissions detected when trying to create a directory" error

Hi, I am encountering the following trying to upgrade from moodle 3.1.15 to 3.5.4.

Invalid permissions detected when trying to create a directory. Turn debugging on for further details.
Debug info: [cachedir]/cachestore_file/default_application is not writable, check permissions.
Error code: invaliddatarootpermissions
Stack trace:

    line 1566 of /lib/setuplib.php: invalid_dataroot_permissions thrown
    line 1744 of /lib/setuplib.php: call to make_writable_directory()
    line 155 of /cache/stores/file/lib.php: call to make_cache_directory()
    line 528 of /cache/classes/helper.php: call to cachestore_file->__construct()
    line 493 of /cache/classes/helper.php: call to cache_helper::purge_store()
    line 1655 of /lib/moodlelib.php: call to cache_helper::purge_all()
    line 331 of /admin/index.php: call to purge_all_caches()

moodledata folder is located at:

$CFG->dataroot = "/var/www/moodledata/";

Permissions should work:

ls -l /var/www/     
total 8
drwxrwxrwx 51 www-data www-data 4096 Mar 21 13:27 html
drwxrwxrwx 10 www-data www-data 4096 Mar 20 12:40 moodledata

I upgrade from php 5.6 to 7.0 too.

Any idea?
Cheers,
Ben