[CentOS] Find and excluding directory

Hi

I have to use find to change the perms of a directory and files within that directory recursively but i need to exclude a directory within the top level directory, as its a netapp and so contains a read only .snapshot dir.

I have tried...

# find /var/data/foo -path './.snapshot' -prune -o -exec chown usera:groupb {} ;

but

chown: changing ownership of `/var/data/foo/.snapshot': Read-only file system chown: changing ownership of `/var/data/foo/.snapshot/hourly.0': Read-only file system chown: changing ownership of `/var/data/foo/.snapshot/hourly.0/filename': Read-only file system

any clue ?

thanks