I recently turned on DLNA on one of my shares and the NAS locked up. after reboot it gets so far and stops at "out of memory". I'm pretty sure DLNA is too much for the amount of files I have, so im fine to turn it off, but I can only access the NAS in read only mode at the moment.
Did you already reboot the NAS and see if that will enable you to change some settings on the admin page? Maybe turn off ReadyDLNA from system > Settings > Services will help.
Also, if you can only successfully boot into volume read-only mode you could try updating to 6.7.2 and if it still won't boot into normal mode you could try an OS Re-install.
