kernfs: clean up struct kernfs_iattrs

Right now, kernfs_iattrs embeds the whole struct iattr, even though it
doesn't really use half of its fields... This both leads to wasting
space and makes the code look awkward. Let's just list the few fields
we need directly in struct kernfs_iattrs.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: merged a number of chunks manually due to fuzz]
Signed-off-by: Paul Moore <paul@paul-moore.com>
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 162f43b8..eb46c3a 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -33,8 +33,8 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
 	kgid_t gid = GLOBAL_ROOT_GID;
 
 	if (target->iattr) {
-		uid = target->iattr->ia_iattr.ia_uid;
-		gid = target->iattr->ia_iattr.ia_gid;
+		uid = target->iattr->ia_uid;
+		gid = target->iattr->ia_gid;
 	}
 
 	kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, uid, gid,