Selinux inode security struct allocation

i'm trying to understand allocation of inode_security_struct in Selinux. I looked for a source code of selinux and there is only one allocation of this struct [on line 230 in hooks.c file](http://lxr.free-electrons.com/source/security/selinux/hooks.c#L225) . This allocation is in LSM hook which is called when inode is created. My question is how Selinux allocate inodes which were created before selinux init? Thanks.