We recently jumped from stable (4.1+dfsg-1+deb8u11) to backports on wordpress to take advantage of the newer REST API functionality required for plugins we use.
After the upgrade, we couldn't upload any media and were presented with the following message.
Unable to create directory wp-content/uploads. Is its parent directory writable by the server?
After a bit of review, a quick workaround was to simply symlink /var/lib/wordpress/wp-content/wp-uploads/ into /usr/share/wordpress/wp-content/
We suspect this may not be the correct, or most secure solution.
Prior to symlinking we attempted to redefine UPLOADs.
define(UPLOADS, '/var/lib/wordpress/wp-content/uploads');
We also noted that changing permissions to a less secure 777 had no impact, so it would seem that the previous apache2 Alias below seems to be in need of some additional configuration to preserve the previous functionality of having the uploads folder only accessed from within /var/lib.
Alias /wp-content /var/lib/wordpress/wp-content
We are looking for the correct solution in how uploads are handled with the new wordpress version, and would suggest a maintainer to drop a similar comment in the README.Debian for others going through the upgrade process.
cheers,
Ian