ocfs2: Use BH_JBDPrivateStart instead of BH_Unshadow

This is safer. We no longer have to worry about tracking changes to
jbd_state_bits.

Signed-off-by: Mark Fasheh <mfasheh@suse.com>

fs/ocfs2/buffer_head_io.c

@@ -42,11 +42,10 @@
 /*
  * Bits on bh->b_state used by ocfs2.
  *
- * These MUST be after the JBD2 bits.  Currently BH_Unshadow is the last
+ * These MUST be after the JBD2 bits.  Hence, we use BH_JBDPrivateStart.
- * JBD2 bit.
  */
 enum ocfs2_state_bits {
-	BH_NeedsValidate = BH_Unshadow + 1,
+	BH_NeedsValidate = BH_JBDPrivateStart,
 };
 
 /* Expand the magic b_state functions */