diff --git a/fs/xfs/libxfs/xfs_rtbitmap.c b/fs/xfs/libxfs/xfs_rtbitmap.c
index ea45584a9913..e47b99e59f60 100644
--- a/fs/xfs/libxfs/xfs_rtbitmap.c
+++ b/fs/xfs/libxfs/xfs_rtbitmap.c
@@ -1016,3 +1016,73 @@ xfs_rtfree_extent(
 	}
 	return 0;
 }
+
+/* Find all the free records within a given range. */
+int
+xfs_rtalloc_query_range(
+	struct xfs_trans		*tp,
+	struct xfs_rtalloc_rec		*low_rec,
+	struct xfs_rtalloc_rec		*high_rec,
+	xfs_rtalloc_query_range_fn	fn,
+	void				*priv)
+{
+	struct xfs_rtalloc_rec		rec;
+	struct xfs_mount		*mp = tp->t_mountp;
+	xfs_rtblock_t			rtstart;
+	xfs_rtblock_t			rtend;
+	xfs_rtblock_t			rem;
+	int				is_free;
+	int				error = 0;
+
+	if (low_rec->ar_startblock > high_rec->ar_startblock)
+		return -EINVAL;
+	else if (low_rec->ar_startblock == high_rec->ar_startblock)
+		return 0;
+
+	/* Iterate the bitmap, looking for discrepancies. */
+	rtstart = low_rec->ar_startblock;
+	rem = high_rec->ar_startblock - rtstart;
+	while (rem) {
+		/* Is the first block free? */
+		error = xfs_rtcheck_range(mp, tp, rtstart, 1, 1, &rtend,
+				&is_free);
+		if (error)
+			break;
+
+		/* How long does the extent go for? */
+		error = xfs_rtfind_forw(mp, tp, rtstart,
+				high_rec->ar_startblock - 1, &rtend);
+		if (error)
+			break;
+
+		if (is_free) {
+			rec.ar_startblock = rtstart;
+			rec.ar_blockcount = rtend - rtstart + 1;
+
+			error = fn(tp, &rec, priv);
+			if (error)
+				break;
+		}
+
+		rem -= rtend - rtstart + 1;
+		rtstart = rtend + 1;
+	}
+
+	return error;
+}
+
+/* Find all the free records. */
+int
+xfs_rtalloc_query_all(
+	struct xfs_trans		*tp,
+	xfs_rtalloc_query_range_fn	fn,
+	void				*priv)
+{
+	struct xfs_rtalloc_rec		keys[2];
+
+	keys[0].ar_startblock = 0;
+	keys[1].ar_startblock = tp->t_mountp->m_sb.sb_rblocks;
+	keys[0].ar_blockcount = keys[1].ar_blockcount = 0;
+
+	return xfs_rtalloc_query_range(tp, &keys[0], &keys[1], fn, priv);
+}
diff --git a/fs/xfs/xfs_rtalloc.h b/fs/xfs/xfs_rtalloc.h
index 51dd3c726608..f13133e6f19f 100644
--- a/fs/xfs/xfs_rtalloc.h
+++ b/fs/xfs/xfs_rtalloc.h
@@ -23,6 +23,16 @@
 struct xfs_mount;
 struct xfs_trans;
 
+struct xfs_rtalloc_rec {
+	xfs_rtblock_t		ar_startblock;
+	xfs_rtblock_t		ar_blockcount;
+};
+
+typedef int (*xfs_rtalloc_query_range_fn)(
+	struct xfs_trans	*tp,
+	struct xfs_rtalloc_rec	*rec,
+	void			*priv);
+
 #ifdef CONFIG_XFS_RT
 /*
  * Function prototypes for exported functions.
@@ -118,13 +128,21 @@ int xfs_rtmodify_summary(struct xfs_mount *mp, struct xfs_trans *tp, int log,
 int xfs_rtfree_range(struct xfs_mount *mp, struct xfs_trans *tp,
 		     xfs_rtblock_t start, xfs_extlen_t len,
 		     struct xfs_buf **rbpp, xfs_fsblock_t *rsb);
-
-
+int xfs_rtalloc_query_range(struct xfs_trans *tp,
+			    struct xfs_rtalloc_rec *low_rec,
+			    struct xfs_rtalloc_rec *high_rec,
+			    xfs_rtalloc_query_range_fn fn,
+			    void *priv);
+int xfs_rtalloc_query_all(struct xfs_trans *tp,
+			  xfs_rtalloc_query_range_fn fn,
+			  void *priv);
 #else
 # define xfs_rtallocate_extent(t,b,min,max,l,f,p,rb)    (ENOSYS)
 # define xfs_rtfree_extent(t,b,l)                       (ENOSYS)
 # define xfs_rtpick_extent(m,t,l,rb)                    (ENOSYS)
 # define xfs_growfs_rt(mp,in)                           (ENOSYS)
+# define xfs_rtalloc_query_range(t,l,h,f,p)             (ENOSYS)
+# define xfs_rtalloc_query_all(t,f,p)                   (ENOSYS)
 static inline int		/* error */
 xfs_rtmount_init(
 	xfs_mount_t	*mp)	/* file system mount structure */