[CentOS] xfs question

Hi, folks,

   CentOS 6.6 (well, just updated with CR). I have some xfs filesystems on
a RAID. They've been mounted with the option of defaults. Will it break
the whole thing if I now change that to inode64, or was that something
I needed to do when the fs was created, or is there some conversion I
can run that won't break everything?

       mark