I guess you are not the owner of the folder..
I see you are using Ubuntu, its UIDs start at 1000 where as CentOS start at 500
so your first ( and I guess Only user ) on each install are 'miss matched'
easiest way to get round this is make them match..
The below assumes the above to be true and that you want to work with files you 'own' on each distro
If that is not the case, more info required
Do not login..
instead go to a console ( ctrl+alt+F1 ) and login as root
figure out UID/GID's
a quick way to confirm the UID/GID is
ls -l -n /home /path/to/volume/home
assuming Ubuntu account is 1000..
usermod -u 1000 <username>
groupmod -g 1000 <your group, probably same as username>
now your CentOS UID/GID will be in-sync with the Ubuntu's
of course you could do it the other way round, in Ubuntu change to 500
This is going to be a tiny bit 'harder', as you won't have a real root account..
login as yourself,
You now have a 'real' root account
Oh, logout of root ( exit or ctrl+d ) and get back to graphical Login with (ctrl+)alt+f7 ( sometimes f8 or f9 )