gfs2: make gfs2_holder.gh_owner_pid be a struct pid *

The gl_owner_pid field is used to get the holder task by its pid and check
whether the current is a holder, so make it in a proper manner, i.e.  via the
struct pid * manipulations.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 513aaf0..4b724e7 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -151,7 +151,7 @@
 	struct list_head gh_list;
 
 	struct gfs2_glock *gh_gl;
-	pid_t gh_owner_pid;
+	struct pid *gh_owner_pid;
 	unsigned int gh_state;
 	unsigned gh_flags;