[CentOS] File Permissions or Partition Write/Read for everyone

Hello all,

I am kinda new to Linux, FreeBSD...most Windows user, anyway. I got a little problem here maybe you can help me solve it.

I just bought a new 500Gb HDD which i formated using ext3 under Centos 5, my plan was to use it under FreeNAS as another Backup File Disk(It has already like 400gb of data), when I try to access the disk via samba/cifs I just have the read attribute or permission, how can i change the whole partition permission rights to be accessible to write/read for everyone? (I will mantain the security using samba users and groups of course.), or do I have to apply the chmod comand to the main folder? I'm really stuck here.

Thank you

Victor.

P.S. Sorry for my english.