SVN Permissions Error Using svn:// During Commit

SVN Permissions Error Using svn:// During Commit

So I created a new repository and I am successfully able to checkout,
edit, and commit files. This repository is going to be accessed by
multiple people, none of which can currently commit to it (but they can
checkout). The following errors occur when they try to commit:
$ svnserve -d
$ svn commit -m "Changes."
Transmitting file data .svn: Commit failed (details follow):
svn: Can't create directory '/tmp_mnt/home/.../repo/db/transactions/6-1.txn
After chmod 777 the /transactions/ directory, I got the same error but for
another file in /db/. From searching this problem, some people claimed
that SELinux had something to do with it and setenforce 0 would turn it
off, but this did not work.
Edit: Yet another failed solution was changing the owner of the repository
chown www-data repo/ -R.