staging: lustre: clio: incorrect assertions in 'enable-invariants'

Fixed several incorrect assumptions in 'enable-invariants'.
Signed-off-by: Niu Yawei <yawei.niu@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3521
Reviewed-on: http://review.whamcloud.com/6832Reviewed-by: Bobi Jam <bobijam@gmail.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/cl_page.c

@@ -498,7 +498,7 @@ void cl_page_disown0(const struct lu_env *env,
 
 	state = pg->cp_state;
 	PINVRNT(env, pg, state == CPS_OWNED || state == CPS_FREEING);
-	PINVRNT(env, pg, cl_page_invariant(pg));
+	PINVRNT(env, pg, cl_page_invariant(pg) || state == CPS_FREEING);
 	cl_page_owner_clear(pg);
 
 	if (state == CPS_OWNED)
@@ -670,7 +670,8 @@ EXPORT_SYMBOL(cl_page_unassume);
 void cl_page_disown(const struct lu_env *env,
 		    struct cl_io *io, struct cl_page *pg)
 {
-	PINVRNT(env, pg, cl_page_is_owned(pg, io));
+	PINVRNT(env, pg, cl_page_is_owned(pg, io) ||
+		pg->cp_state == CPS_FREEING);
 
 	io = cl_io_top(io);
 	cl_page_disown0(env, io, pg);