As with a lot of these posts, I’m writing this here to save me *literally* hours (well, minutes) of searching the internet. So, in order to help future Mike (and anyone else watching) out…..
so, you installed Drupal… and your reports page is showing ‘cannot access the file system’ when you know full well you can because you checked…
Then, you remember SELinux is installed… You try turning it off (setenforce 0) and you see it works fine! (So you turn it back on with setenforce 1 because you don’t want hackers!)
Here is what you need to run as root:
chcon -R -t httpd_sys_rw_content_t files/
Original source: https://tumblr.mikeandhan.co.uk/post/186863239645/selinux-and-drupal-cant-write-files