A few questions: Where is your Spark installed to? Is it a remote filesystem? If local, what is the filesystem type? How much disk space do you have fee on that partition?
As a side note- its a bad idea to be doing normal user operations as root. You are just inviting yourself trouble. Use a non-priviledged user when possible.
But do you have permissions to write? If it is NFS, and you are root, is root_squash turned on (it is unless you specify no_root_squash on the server exports) you do not have permissions to write.