Broken rights on tmp directory

Server
1

Continue from Error uploading file "%filename%": Error write on disk

The right to change when i restart the computer on directory /var/www/owncloud/data/tmp…

I need to run chown -R www-data:www-data /var/www/owncloud/data/tmp every times after reboot.

How fix this?

2

Is this a special partition or just a folder? Normally the permissions don’t change itself, there is probably a process related to it. Can you give more details?