diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
index 17f7c0d1aaa452..b6828f92c131fb 100644
--- a/libxfs/xfs_format.h
+++ b/libxfs/xfs_format.h
@@ -858,6 +858,7 @@ enum xfs_metafile_type {
 	XFS_METAFILE_RTBITMAP,		/* rt bitmap */
 	XFS_METAFILE_RTSUMMARY,		/* rt summary */
 	XFS_METAFILE_RTRMAP,		/* rt rmap */
+	XFS_METAFILE_RTREFCOUNT,	/* rt refcount */
 
 	XFS_METAFILE_MAX
 } __packed;
@@ -870,7 +871,8 @@ enum xfs_metafile_type {
 	{ XFS_METAFILE_PRJQUOTA,	"prjquota" }, \
 	{ XFS_METAFILE_RTBITMAP,	"rtbitmap" }, \
 	{ XFS_METAFILE_RTSUMMARY,	"rtsummary" }, \
-	{ XFS_METAFILE_RTRMAP,		"rtrmap" }
+	{ XFS_METAFILE_RTRMAP,		"rtrmap" }, \
+	{ XFS_METAFILE_RTREFCOUNT,	"rtrefcount" }
 
 /*
  * On-disk inode structure.
diff --git a/libxfs/xfs_inode_buf.c b/libxfs/xfs_inode_buf.c
index 0278fbb6379701..0be0625857002c 100644
--- a/libxfs/xfs_inode_buf.c
+++ b/libxfs/xfs_inode_buf.c
@@ -453,6 +453,11 @@ xfs_dinode_verify_fork(
 			if (!xfs_has_rmapbt(mp))
 				return __this_address;
 			break;
+		case XFS_METAFILE_RTREFCOUNT:
+			/* same comment about growfs and rmap inodes applies */
+			if (!xfs_has_reflink(mp))
+				return __this_address;
+			break;
 		default:
 			return __this_address;
 		}
diff --git a/libxfs/xfs_inode_fork.c b/libxfs/xfs_inode_fork.c
index e4f866969bf1b6..f690c746805fad 100644
--- a/libxfs/xfs_inode_fork.c
+++ b/libxfs/xfs_inode_fork.c
@@ -270,6 +270,9 @@ xfs_iformat_data_fork(
 			switch (ip->i_metatype) {
 			case XFS_METAFILE_RTRMAP:
 				return xfs_iformat_rtrmap(ip, dip);
+			case XFS_METAFILE_RTREFCOUNT:
+				ASSERT(0); /* to be implemented later */
+				return -EFSCORRUPTED;
 			default:
 				break;
 			}
@@ -618,6 +621,9 @@ xfs_iflush_fork(
 		case XFS_METAFILE_RTRMAP:
 			xfs_iflush_rtrmap(ip, dip);
 			break;
+		case XFS_METAFILE_RTREFCOUNT:
+			ASSERT(0); /* to be implemented later */
+			break;
 		default:
 			ASSERT(0);
 			break;
diff --git a/libxfs/xfs_rtgroup.c b/libxfs/xfs_rtgroup.c
index 7e69b6bf96f1ac..f7bacce8500c0c 100644
--- a/libxfs/xfs_rtgroup.c
+++ b/libxfs/xfs_rtgroup.c
@@ -364,6 +364,13 @@ static const struct xfs_rtginode_ops xfs_rtginode_ops[XFS_RTGI_MAX] = {
 		.enabled	= xfs_has_rmapbt,
 		.create		= xfs_rtrmapbt_create,
 	},
+	[XFS_RTGI_REFCOUNT] = {
+		.name		= "refcount",
+		.metafile_type	= XFS_METAFILE_RTREFCOUNT,
+		.fmt_mask	= 1U << XFS_DINODE_FMT_META_BTREE,
+		/* same comment about growfs and rmap inodes applies here */
+		.enabled	= xfs_has_reflink,
+	},
 };
 
 /* Return the shortname of this rtgroup inode. */
diff --git a/libxfs/xfs_rtgroup.h b/libxfs/xfs_rtgroup.h
index 6ff222a053674d..2663f2d849e295 100644
--- a/libxfs/xfs_rtgroup.h
+++ b/libxfs/xfs_rtgroup.h
@@ -15,6 +15,7 @@ enum xfs_rtg_inodes {
 	XFS_RTGI_BITMAP,	/* allocation bitmap */
 	XFS_RTGI_SUMMARY,	/* allocation summary */
 	XFS_RTGI_RMAP,		/* rmap btree inode */
+	XFS_RTGI_REFCOUNT,	/* refcount btree inode */
 
 	XFS_RTGI_MAX,
 };
@@ -80,6 +81,11 @@ static inline struct xfs_inode *rtg_rmap(const struct xfs_rtgroup *rtg)
 	return rtg->rtg_inodes[XFS_RTGI_RMAP];
 }
 
+static inline struct xfs_inode *rtg_refcount(const struct xfs_rtgroup *rtg)
+{
+	return rtg->rtg_inodes[XFS_RTGI_REFCOUNT];
+}
+
 /* Passive rtgroup references */
 static inline struct xfs_rtgroup *
 xfs_rtgroup_get(
diff --git a/libxfs/xfs_rtrefcount_btree.c b/libxfs/xfs_rtrefcount_btree.c
index ea05b1a48eab62..46c62bd63458f4 100644
--- a/libxfs/xfs_rtrefcount_btree.c
+++ b/libxfs/xfs_rtrefcount_btree.c
@@ -24,6 +24,7 @@
 #include "xfs_cksum.h"
 #include "xfs_rtgroup.h"
 #include "xfs_rtbitmap.h"
+#include "xfs_metafile.h"
 
 static struct kmem_cache	*xfs_rtrefcountbt_cur_cache;
 
@@ -279,12 +280,10 @@ xfs_rtrefcountbt_init_cursor(
 	struct xfs_trans	*tp,
 	struct xfs_rtgroup	*rtg)
 {
-	struct xfs_inode	*ip = NULL;
+	struct xfs_inode	*ip = rtg_refcount(rtg);
 	struct xfs_mount	*mp = rtg_mount(rtg);
 	struct xfs_btree_cur	*cur;
 
-	return NULL; /* XXX */
-
 	xfs_assert_ilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL);
 
 	cur = xfs_btree_alloc_cursor(mp, tp, &xfs_rtrefcountbt_ops,
@@ -314,6 +313,7 @@ xfs_rtrefcountbt_commit_staged_btree(
 	int			flags = XFS_ILOG_CORE | XFS_ILOG_DBROOT;
 
 	ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
+	ASSERT(ifake->if_fork->if_format == XFS_DINODE_FMT_META_BTREE);
 
 	/*
 	 * Free any resources hanging off the real fork, then shallow-copy the
