diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 3e343c7..657f612 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -164,7 +164,7 @@
 	       (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL));
 	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
 	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
-	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);
+	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0);
 
 	if (lock_flags & XFS_IOLOCK_EXCL)
 		mrupdate_nested(&ip->i_iolock, XFS_IOLOCK_DEP(lock_flags));
@@ -212,7 +212,7 @@
 	       (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL));
 	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
 	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
-	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);
+	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0);
 
 	if (lock_flags & XFS_IOLOCK_EXCL) {
 		if (!mrtryupdate(&ip->i_iolock))
@@ -281,7 +281,7 @@
 	       (XFS_MMAPLOCK_SHARED | XFS_MMAPLOCK_EXCL));
 	ASSERT((lock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)) !=
 	       (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
-	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_DEP_MASK)) == 0);
+	ASSERT((lock_flags & ~(XFS_LOCK_MASK | XFS_LOCK_SUBCLASS_MASK)) == 0);
 	ASSERT(lock_flags != 0);
 
 	if (lock_flags & XFS_IOLOCK_EXCL)
@@ -364,30 +364,38 @@
 
 /*
  * Bump the subclass so xfs_lock_inodes() acquires each lock with a different
- * value. This shouldn't be called for page fault locking, but we also need to
- * ensure we don't overrun the number of lockdep subclasses for the iolock or
- * mmaplock as that is limited to 12 by the mmap lock lockdep annotations.
+ * value. This can be called for any type of inode lock combination, including
+ * parent locking. Care must be taken to ensure we don't overrun the subclass
+ * storage fields in the class mask we build.
  */
 static inline int
 xfs_lock_inumorder(int lock_mode, int subclass)
 {
+	int	class = 0;
+
+	ASSERT(!(lock_mode & (XFS_ILOCK_PARENT | XFS_ILOCK_RTBITMAP |
+			      XFS_ILOCK_RTSUM)));
+
 	if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)) {
-		ASSERT(subclass + XFS_LOCK_INUMORDER <
-			(1 << (XFS_MMAPLOCK_SHIFT - XFS_IOLOCK_SHIFT)));
-		lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_IOLOCK_SHIFT;
+		ASSERT(subclass <= XFS_IOLOCK_MAX_SUBCLASS);
+		ASSERT(subclass + XFS_IOLOCK_PARENT_VAL <
+						MAX_LOCKDEP_SUBCLASSES);
+		class += subclass << XFS_IOLOCK_SHIFT;
+		if (lock_mode & XFS_IOLOCK_PARENT)
+			class += XFS_IOLOCK_PARENT_VAL << XFS_IOLOCK_SHIFT;
 	}
 
 	if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) {
-		ASSERT(subclass + XFS_LOCK_INUMORDER <
-			(1 << (XFS_ILOCK_SHIFT - XFS_MMAPLOCK_SHIFT)));
-		lock_mode |= (subclass + XFS_LOCK_INUMORDER) <<
-							XFS_MMAPLOCK_SHIFT;
+		ASSERT(subclass <= XFS_MMAPLOCK_MAX_SUBCLASS);
+		class += subclass << XFS_MMAPLOCK_SHIFT;
 	}
 
-	if (lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL))
-		lock_mode |= (subclass + XFS_LOCK_INUMORDER) << XFS_ILOCK_SHIFT;
+	if (lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)) {
+		ASSERT(subclass <= XFS_ILOCK_MAX_SUBCLASS);
+		class += subclass << XFS_ILOCK_SHIFT;
+	}
 
-	return lock_mode;
+	return (lock_mode & ~XFS_LOCK_SUBCLASS_MASK) | class;
 }
 
 /*
@@ -399,6 +407,11 @@
  * transaction (such as truncate). This can result in deadlock since the long
  * running trans might need to wait for the inode we just locked in order to
  * push the tail and free space in the log.
+ *
+ * xfs_lock_inodes() can only be used to lock one type of lock at a time -
+ * the iolock, the mmaplock or the ilock, but not more than one at a time. If we
+ * lock more than one at a time, lockdep will report false positives saying we
+ * have violated locking orders.
  */
 void
 xfs_lock_inodes(
@@ -409,8 +422,29 @@
 	int		attempts = 0, i, j, try_lock;
 	xfs_log_item_t	*lp;
 
-	/* currently supports between 2 and 5 inodes */
+	/*
+	 * Currently supports between 2 and 5 inodes with exclusive locking.  We
+	 * support an arbitrary depth of locking here, but absolute limits on
+	 * inodes depend on the the type of locking and the limits placed by
+	 * lockdep annotations in xfs_lock_inumorder.  These are all checked by
+	 * the asserts.
+	 */
 	ASSERT(ips && inodes >= 2 && inodes <= 5);
+	ASSERT(lock_mode & (XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL |
+			    XFS_ILOCK_EXCL));
+	ASSERT(!(lock_mode & (XFS_IOLOCK_SHARED | XFS_MMAPLOCK_SHARED |
+			      XFS_ILOCK_SHARED)));
+	ASSERT(!(lock_mode & XFS_IOLOCK_EXCL) ||
+		inodes <= XFS_IOLOCK_MAX_SUBCLASS + 1);
+	ASSERT(!(lock_mode & XFS_MMAPLOCK_EXCL) ||
+		inodes <= XFS_MMAPLOCK_MAX_SUBCLASS + 1);
+	ASSERT(!(lock_mode & XFS_ILOCK_EXCL) ||
+		inodes <= XFS_ILOCK_MAX_SUBCLASS + 1);
+
+	if (lock_mode & XFS_IOLOCK_EXCL) {
+		ASSERT(!(lock_mode & (XFS_MMAPLOCK_EXCL | XFS_ILOCK_EXCL)));
+	} else if (lock_mode & XFS_MMAPLOCK_EXCL)
+		ASSERT(!(lock_mode & XFS_ILOCK_EXCL));
 
 	try_lock = 0;
 	i = 0;
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 8f22d20..ca9e119 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -284,9 +284,9 @@
  * Flags for lockdep annotations.
  *
  * XFS_LOCK_PARENT - for directory operations that require locking a
- * parent directory inode and a child entry inode.  The parent gets locked
- * with this flag so it gets a lockdep subclass of 1 and the child entry
- * lock will have a lockdep subclass of 0.
+ * parent directory inode and a child entry inode. IOLOCK requires nesting,
+ * MMAPLOCK does not support this class, ILOCK requires a single subclass
+ * to differentiate parent from child.
  *
  * XFS_LOCK_RTBITMAP/XFS_LOCK_RTSUM - the realtime device bitmap and summary
  * inodes do not participate in the normal lock order, and thus have their
@@ -295,30 +295,63 @@
  * XFS_LOCK_INUMORDER - for locking several inodes at the some time
  * with xfs_lock_inodes().  This flag is used as the starting subclass
  * and each subsequent lock acquired will increment the subclass by one.
- * So the first lock acquired will have a lockdep subclass of 4, the
- * second lock will have a lockdep subclass of 5, and so on. It is
- * the responsibility of the class builder to shift this to the correct
- * portion of the lock_mode lockdep mask.
+ * However, MAX_LOCKDEP_SUBCLASSES == 8, which means we are greatly
+ * limited to the subclasses we can represent via nesting. We need at least
+ * 5 inodes nest depth for the ILOCK through rename, and we also have to support
+ * XFS_ILOCK_PARENT, which gives 6 subclasses. Then we have XFS_ILOCK_RTBITMAP
+ * and XFS_ILOCK_RTSUM, which are another 2 unique subclasses, so that's all
+ * 8 subclasses supported by lockdep.
+ *
+ * This also means we have to number the sub-classes in the lowest bits of
+ * the mask we keep, and we have to ensure we never exceed 3 bits of lockdep
+ * mask and we can't use bit-masking to build the subclasses. What a mess.
+ *
+ * Bit layout:
+ *
+ * Bit		Lock Region
+ * 16-19	XFS_IOLOCK_SHIFT dependencies
+ * 20-23	XFS_MMAPLOCK_SHIFT dependencies
+ * 24-31	XFS_ILOCK_SHIFT dependencies
+ *
+ * IOLOCK values
+ *
+ * 0-3		subclass value
+ * 4-7		PARENT subclass values
+ *
+ * MMAPLOCK values
+ *
+ * 0-3		subclass value
+ * 4-7		unused
+ *
+ * ILOCK values
+ * 0-4		subclass values
+ * 5		PARENT subclass (not nestable)
+ * 6		RTBITMAP subclass (not nestable)
+ * 7		RTSUM subclass (not nestable)
+ * 
  */
-#define XFS_LOCK_PARENT		1
-#define XFS_LOCK_RTBITMAP	2
-#define XFS_LOCK_RTSUM		3
-#define XFS_LOCK_INUMORDER	4
+#define XFS_IOLOCK_SHIFT		16
+#define XFS_IOLOCK_PARENT_VAL		4
+#define XFS_IOLOCK_MAX_SUBCLASS		(XFS_IOLOCK_PARENT_VAL - 1)
+#define XFS_IOLOCK_DEP_MASK		0x000f0000
+#define	XFS_IOLOCK_PARENT		(XFS_IOLOCK_PARENT_VAL << XFS_IOLOCK_SHIFT)
 
-#define XFS_IOLOCK_SHIFT	16
-#define	XFS_IOLOCK_PARENT	(XFS_LOCK_PARENT << XFS_IOLOCK_SHIFT)
+#define XFS_MMAPLOCK_SHIFT		20
+#define XFS_MMAPLOCK_NUMORDER		0
+#define XFS_MMAPLOCK_MAX_SUBCLASS	3
+#define XFS_MMAPLOCK_DEP_MASK		0x00f00000
 
-#define XFS_MMAPLOCK_SHIFT	20
+#define XFS_ILOCK_SHIFT			24
+#define XFS_ILOCK_PARENT_VAL		5
+#define XFS_ILOCK_MAX_SUBCLASS		(XFS_ILOCK_PARENT_VAL - 1)
+#define XFS_ILOCK_RTBITMAP_VAL		6
+#define XFS_ILOCK_RTSUM_VAL		7
+#define XFS_ILOCK_DEP_MASK		0xff000000
+#define	XFS_ILOCK_PARENT		(XFS_ILOCK_PARENT_VAL << XFS_ILOCK_SHIFT)
+#define	XFS_ILOCK_RTBITMAP		(XFS_ILOCK_RTBITMAP_VAL << XFS_ILOCK_SHIFT)
+#define	XFS_ILOCK_RTSUM			(XFS_ILOCK_RTSUM_VAL << XFS_ILOCK_SHIFT)
 
-#define XFS_ILOCK_SHIFT		24
-#define	XFS_ILOCK_PARENT	(XFS_LOCK_PARENT << XFS_ILOCK_SHIFT)
-#define	XFS_ILOCK_RTBITMAP	(XFS_LOCK_RTBITMAP << XFS_ILOCK_SHIFT)
-#define	XFS_ILOCK_RTSUM		(XFS_LOCK_RTSUM << XFS_ILOCK_SHIFT)
-
-#define XFS_IOLOCK_DEP_MASK	0x000f0000
-#define XFS_MMAPLOCK_DEP_MASK	0x00f00000
-#define XFS_ILOCK_DEP_MASK	0xff000000
-#define XFS_LOCK_DEP_MASK	(XFS_IOLOCK_DEP_MASK | \
+#define XFS_LOCK_SUBCLASS_MASK	(XFS_IOLOCK_DEP_MASK | \
 				 XFS_MMAPLOCK_DEP_MASK | \
 				 XFS_ILOCK_DEP_MASK)