[GFS2] Shrink gfs2_inode (8) - i_vn

This shrinks the size of the gfs2_inode by 8 bytes by
replacing the version counter with a one bit valid/invalid
flag.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index f6177fc..e467780 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -145,7 +145,7 @@
 		if (unlikely(error))
 			goto fail_put;
 
-		ip->i_vn = ip->i_gl->gl_vn - 1;
+		set_bit(GIF_INVALID, &ip->i_flags);
 		error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, &ip->i_iopen_gh);
 		if (unlikely(error))
 			goto fail_iopen;
@@ -242,7 +242,7 @@
 
 	error = gfs2_dinode_in(ip, dibh->b_data);
 	brelse(dibh);
-	ip->i_vn = ip->i_gl->gl_vn;
+	clear_bit(GIF_INVALID, &ip->i_flags);
 
 	return error;
 }