xfs: define the on-disk realtime refcount btree format

Start filling out the rtrefcount btree implementation. Start with the
on-disk btree format; add everything needed to read, write and
manipulate refcount btree blocks. This prepares the way for connecting
the btree operations implementation.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

11 files changed, 377 insertions, 4 deletions

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index df27b6ae0d6c..7cf622753b6d 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -48,6 +48,7 @@ xfs-y				+= $(addprefix libxfs/, \
 				   xfs_rtrmap_btree.o \
 				   xfs_refcount.o \
 				   xfs_refcount_btree.o \
+				   xfs_rtrefcount_btree.o \
 				   xfs_sb.o \
 				   xfs_swapext.o \
 				   xfs_symlink_remote.o \
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 90ad8dbfec38..0197cdbcaa3d 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -1227,6 +1227,7 @@ xfs_btree_set_refs(
 		xfs_buf_set_ref(bp, XFS_RMAP_BTREE_REF);
 		break;
 	case XFS_BTNUM_REFC:
+	case XFS_BTNUM_RTREFC:
 		xfs_buf_set_ref(bp, XFS_REFC_BTREE_REF);
 		break;
 	default:
@@ -5289,6 +5290,8 @@ xfs_btree_maxlevels(
 		return mp->m_refc_maxlevels;
 	case XFS_BTNUM_RTRMAP:
 		return mp->m_rtrmap_maxlevels;
+	case XFS_BTNUM_RTREFC:
+		return mp->m_rtrefc_maxlevels;
 	default:
 		break;
 	}
@@ -5299,6 +5302,7 @@ xfs_btree_maxlevels(
 	ret = max(ret, M_IGEO(mp)->inobt_maxlevels);
 	ret = max(ret, mp->m_rmap_maxlevels);
 	ret = max(ret, mp->m_rtrmap_maxlevels);
+	ret = max(ret, mp->m_rtrefc_maxlevels);
 	return max(ret, mp->m_refc_maxlevels);
 }
 
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index e6f9509b20a6..e0011e9fcfbe 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -38,6 +38,7 @@ union xfs_btree_key {
 	struct xfs_refcount_key		refc;
 	struct xfs_rtrmap_key		rtrmap;
 	struct xfs_rtrmap_key		__rtrmap_bigkey[2];
+	struct xfs_rtrefcount_key	rtrefc;
 };
 
 union xfs_btree_rec {
@@ -48,6 +49,7 @@ union xfs_btree_rec {
 	struct xfs_rmap_rec		rmap;
 	struct xfs_refcount_rec		refc;
 	struct xfs_rtrmap_rec		rtrmap;
+	struct xfs_rtrefcount_rec	rtrefc;
 };
 
 /*
@@ -182,6 +184,11 @@ union xfs_btree_irec {
 	struct xfs_refcount_irec	rc;
 };
 
+struct xbtree_refc {
+	unsigned long	nr_ops;		/* # record updates */
+	int		shape_changes;	/* # of extent splits */
+};
+
 /* Per-AG btree information. */
 struct xfs_btree_cur_ag {
 	union {
@@ -190,10 +197,7 @@ struct xfs_btree_cur_ag {
 	};
 	xfs_agnumber_t		agno;
 	union {
-		struct {
-			unsigned long nr_ops;	/* # record updates */
-			int	shape_changes;	/* # of extent splits */
-		} refc;
+		struct xbtree_refc	refc;
 		struct {
 			bool	active;		/* allocation cursor state */
 		} abt;
@@ -213,6 +217,7 @@ struct xfs_btree_cur_ino {
 
 /* For extent swap, ignore owner check in verifier */
 #define	XFS_BTCUR_BMBT_INVALID_OWNER	(1 << 1)
+	struct xbtree_refc		refc;
 };
 
 struct xfs_btree_level {
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index 8a6d2e25fe1d..e26fe754097b 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -1898,6 +1898,7 @@ struct xfs_refcount_irec {
 
 #define MAXREFCOUNT	((xfs_nlink_t)~0U)
 #define MAXREFCEXTLEN	((xfs_extlen_t)~0U)
+#define MAXRTREFCEXTLEN	((xfs_filblks_t)~0U)
 
 /* btree pointer type */
 typedef __be32 xfs_refcount_ptr_t;
@@ -1910,6 +1911,33 @@ typedef __be32 xfs_refcount_ptr_t;
 #define	XFS_RTREFC_CRC_MAGIC	0x52434e54	/* 'RCNT' */
 
 /*
+ * Extents that are being used to stage a copy on write are stored
+ * in the refcount btree with a refcount of 1 and the upper bit set
+ * on the startblock.  This speeds up mount time deletion of stale
+ * staging extents because they're all at the right side of the tree.
+ */
+#define XFS_RTREFC_COW_START		((xfs_fsblock_t)(1ULL << 63))
+#define RTREFCNTBT_COWFLAG_BITLEN	1
+#define RTREFCNTBT_RTBLOCK_BITLEN	63
+
+/*
+ * Reference count record for realtime volumes.  Note that the units here are
+ * blocks, even though allocations are done in units of rt extents.
+ */
+struct xfs_rtrefcount_rec {
+	__be64		rc_startblock;	/* starting block number */
+	__be64		rc_blockcount;	/* count of blocks */
+	__be32		rc_refcount;	/* number of inodes linked here */
+} __attribute__((packed));
+
+struct xfs_rtrefcount_key {
+	__be64		rc_startblock;	/* starting block number */
+};
+
+/* btree pointer type */
+typedef __be64 xfs_rtrefcount_ptr_t;
+
+/*
  * BMAP Btree format definitions
  *
  * This includes both the root block definition that sits inside an inode fork
diff --git a/fs/xfs/libxfs/xfs_rtrefcount_btree.c b/fs/xfs/libxfs/xfs_rtrefcount_btree.c
new file mode 100644
index 000000000000..20319aa49b49
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_rtrefcount_btree.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2021 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_bit.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_inode.h"
+#include "xfs_trans.h"
+#include "xfs_alloc.h"
+#include "xfs_btree.h"
+#include "xfs_btree_staging.h"
+#include "xfs_rtrefcount_btree.h"
+#include "xfs_trace.h"
+#include "xfs_cksum.h"
+#include "xfs_error.h"
+#include "xfs_extent_busy.h"
+#include "xfs_ag_resv.h"
+
+/*
+ * Realtime Reference Count btree.
+ *
+ * This is a btree used to track the owner(s) of a given extent in the realtime
+ * device.  See the comments in xfs_refcount_btree.c for more information.
+ *
+ * This tree is basically the same as the regular refcount btree except that it
+ * doesn't live in free space, and the startblock and blockcount fields have
+ * been widened to 64 bits.
+ */
+
+static struct xfs_btree_cur *
+xfs_rtrefcountbt_dup_cursor(
+	struct xfs_btree_cur	*cur)
+{
+	struct xfs_btree_cur	*new;
+
+	new = xfs_rtrefcountbt_init_cursor(cur->bc_mp, cur->bc_tp,
+			cur->bc_ino.ip);
+
+	/* Copy the flags values since init cursor doesn't get them. */
+	new->bc_ino.flags = cur->bc_ino.flags;
+
+	return new;
+}
+
+static xfs_failaddr_t
+xfs_rtrefcountbt_verify(
+	struct xfs_buf		*bp)
+{
+	struct xfs_mount	*mp = bp->b_target->bt_mount;
+	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
+	xfs_failaddr_t		fa;
+	int			level;
+
+	if (block->bb_magic != cpu_to_be32(XFS_RTREFC_CRC_MAGIC))
+		return __this_address;
+
+	if (!xfs_sb_version_hasreflink(&mp->m_sb))
+		return __this_address;
+	fa = xfs_btree_lblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
+	if (fa)
+		return fa;
+	level = be16_to_cpu(block->bb_level);
+	if (level > mp->m_rtrefc_maxlevels)
+		return __this_address;
+
+	return xfs_btree_lblock_verify(bp, mp->m_rtrefc_mxr[level != 0]);
+}
+
+static void
+xfs_rtrefcountbt_read_verify(
+	struct xfs_buf	*bp)
+{
+	xfs_failaddr_t	fa;
+
+	if (!xfs_btree_lblock_verify_crc(bp))
+		xfs_verifier_error(bp, -EFSBADCRC, __this_address);
+	else {
+		fa = xfs_rtrefcountbt_verify(bp);
+		if (fa)
+			xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+	}
+
+	if (bp->b_error)
+		trace_xfs_btree_corrupt(bp, _RET_IP_);
+}
+
+static void
+xfs_rtrefcountbt_write_verify(
+	struct xfs_buf	*bp)
+{
+	xfs_failaddr_t	fa;
+
+	fa = xfs_rtrefcountbt_verify(bp);
+	if (fa) {
+		trace_xfs_btree_corrupt(bp, _RET_IP_);
+		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+		return;
+	}
+	xfs_btree_lblock_calc_crc(bp);
+
+}
+
+const struct xfs_buf_ops xfs_rtrefcountbt_buf_ops = {
+	.name			= "xfs_rtrefcountbt",
+	.verify_read		= xfs_rtrefcountbt_read_verify,
+	.verify_write		= xfs_rtrefcountbt_write_verify,
+	.verify_struct		= xfs_rtrefcountbt_verify,
+};
+
+static const struct xfs_btree_ops xfs_rtrefcountbt_ops = {
+	.rec_len		= sizeof(struct xfs_rtrefcount_rec),
+	.key_len		= sizeof(struct xfs_rtrefcount_key),
+
+	.dup_cursor		= xfs_rtrefcountbt_dup_cursor,
+	.buf_ops		= &xfs_rtrefcountbt_buf_ops,
+};
+
+/* Initialize a new rt refcount btree cursor. */
+static struct xfs_btree_cur *
+xfs_rtrefcountbt_init_common(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip)
+{
+	struct xfs_btree_cur	*cur;
+
+	cur = xfs_btree_alloc_cursor(mp, tp, XFS_BTNUM_RTREFC);
+	cur->bc_flags = XFS_BTREE_LONG_PTRS | XFS_BTREE_ROOT_IN_INODE |
+			XFS_BTREE_CRC_BLOCKS | XFS_BTREE_IROOT_RECORDS;
+	cur->bc_statoff = XFS_STATS_CALC_INDEX(xs_refcbt_2);
+
+	cur->bc_ino.ip = ip;
+	cur->bc_ino.allocated = 0;
+	cur->bc_ino.flags = 0;
+	cur->bc_ino.refc.nr_ops = 0;
+	cur->bc_ino.refc.shape_changes = 0;
+	cur->bc_ops = &xfs_rtrefcountbt_ops;
+
+	return cur;
+}
+
+/* Allocate a new rt refcount btree cursor. */
+struct xfs_btree_cur *
+xfs_rtrefcountbt_init_cursor(
+	struct xfs_mount	*mp,
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip)
+{
+	struct xfs_btree_cur	*cur;
+	struct xfs_ifork	*ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
+
+	cur = xfs_rtrefcountbt_init_common(mp, tp, ip);
+	cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
+	cur->bc_ino.forksize = XFS_IFORK_SIZE(ip, XFS_DATA_FORK);
+	cur->bc_ino.whichfork = XFS_DATA_FORK;
+	return cur;
+}
+
+/* Create a new rt reverse mapping btree cursor with a fake root for staging. */
+struct xfs_btree_cur *
+xfs_rtrefcountbt_stage_cursor(
+	struct xfs_mount	*mp,
+	struct xfs_inode	*ip,
+	struct xbtree_ifakeroot	*ifake)
+{
+	struct xfs_btree_cur	*cur;
+
+	cur = xfs_rtrefcountbt_init_common(mp, NULL, ip);
+	cur->bc_nlevels = ifake->if_levels;
+	cur->bc_ino.forksize = ifake->if_fork_size;
+	cur->bc_ino.whichfork = -1;
+	xfs_btree_stage_ifakeroot(cur, ifake, NULL);
+	return cur;
+}
+
+/*
+ * Install a new rt reverse mapping btree root.  Caller is responsible for
+ * invalidating and freeing the old btree blocks.
+ */
+void
+xfs_rtrefcountbt_commit_staged_btree(
+	struct xfs_btree_cur	*cur,
+	struct xfs_trans	*tp)
+{
+	struct xbtree_ifakeroot	*ifake = cur->bc_ino.ifake;
+	struct xfs_ifork	*ifp;
+	int			flags = XFS_ILOG_CORE | XFS_ILOG_DBROOT;
+
+	ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
+
+	/*
+	 * Free any resources hanging off the real fork, then shallow-copy the
+	 * staging fork's contents into the real fork to transfer everything
+	 * we just built.
+	 */
+	ifp = XFS_IFORK_PTR(cur->bc_ino.ip, XFS_DATA_FORK);
+	xfs_idestroy_fork(ifp);
+	memcpy(ifp, ifake->if_fork, sizeof(struct xfs_ifork));
+
+	xfs_trans_log_inode(tp, cur->bc_ino.ip, flags);
+	xfs_btree_commit_ifakeroot(cur, tp, XFS_DATA_FORK,
+			&xfs_rtrefcountbt_ops);
+}
+
+/*
+ * Calculate number of records in an refcount btree block.
+ */
+unsigned int
+xfs_rtrefcountbt_maxrecs(
+	struct xfs_mount	*mp,
+	unsigned int		blocklen,
+	bool			leaf)
+{
+	blocklen -= XFS_RTREFCOUNT_BLOCK_LEN;
+
+	if (leaf)
+		return blocklen / sizeof(struct xfs_rtrefcount_rec);
+	return blocklen / (sizeof(struct xfs_rtrefcount_key) +
+			   sizeof(xfs_rtrefcount_ptr_t));
+}
+
+/* Compute the maximum height of an refcount btree. */
+unsigned int
+xfs_rtrefcountbt_compute_maxlevels(
+	struct xfs_mount	*mp,
+	xfs_rfsblock_t		dblocks,
+	xfs_rfsblock_t		rblocks)
+{
+	xfs_rtblock_t		rexts;
+	unsigned int		d_maxlevels, r_maxlevels;
+
+	/*
+	 * The realtime refcountbt lives on the data device, which means that
+	 * its maximum height is constrained by the size of the data device and
+	 * the height required to store one refcount record for each rt extent.
+	 */
+	rexts = div_u64(rblocks, mp->m_sb.sb_rextsize);
+	d_maxlevels = xfs_btree_compute_maxlevels_size(dblocks,
+			mp->m_rtrefc_mnr[1]);
+	r_maxlevels = xfs_btree_compute_maxlevels(mp->m_rtrefc_mnr, rexts);
+
+	/* Add one level to handle the inode root level. */
+	return min(d_maxlevels, r_maxlevels) + 1;
+}
diff --git a/fs/xfs/libxfs/xfs_rtrefcount_btree.h b/fs/xfs/libxfs/xfs_rtrefcount_btree.h
new file mode 100644
index 000000000000..65094c38fe78
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_rtrefcount_btree.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2021 Oracle.  All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#ifndef __XFS_RTREFCOUNT_BTREE_H__
+#define __XFS_RTREFCOUNT_BTREE_H__
+
+struct xfs_buf;
+struct xfs_btree_cur;
+struct xfs_mount;
+struct xbtree_ifakeroot;
+
+/* refcounts only exist on crc enabled filesystems */
+#define XFS_RTREFCOUNT_BLOCK_LEN	XFS_BTREE_LBLOCK_CRC_LEN
+
+struct xfs_btree_cur *xfs_rtrefcountbt_init_cursor(struct xfs_mount *mp,
+				struct xfs_trans *tp, struct xfs_inode *ip);
+struct xfs_btree_cur *xfs_rtrefcountbt_stage_cursor(struct xfs_mount *mp,
+		struct xfs_inode *ip, struct xbtree_ifakeroot *ifake);
+void xfs_rtrefcountbt_commit_staged_btree(struct xfs_btree_cur *cur,
+		struct xfs_trans *tp);
+unsigned int xfs_rtrefcountbt_maxrecs(struct xfs_mount *mp,
+		unsigned int blocklen, bool leaf);
+unsigned int xfs_rtrefcountbt_compute_maxlevels(struct xfs_mount *mp,
+		xfs_rfsblock_t dblocks, xfs_rfsblock_t rblocks);
+
+/*
+ * Addresses of records, keys, and pointers within an incore rtrefcountbt block.
+ *
+ * (note that some of these may appear unused, but they are used in userspace)
+ */
+static inline struct xfs_rtrefcount_rec *
+xfs_rtrefcount_rec_addr(
+	struct xfs_btree_block	*block,
+	unsigned int		index)
+{
+	return (struct xfs_rtrefcount_rec *)
+		((char *)block + XFS_RTREFCOUNT_BLOCK_LEN +
+		 (index - 1) * sizeof(struct xfs_rtrefcount_rec));
+}
+
+static inline struct xfs_rtrefcount_key *
+xfs_rtrefcount_key_addr(
+	struct xfs_btree_block	*block,
+	unsigned int		index)
+{
+	return (struct xfs_rtrefcount_key *)
+		((char *)block + XFS_RTREFCOUNT_BLOCK_LEN +
+		 (index - 1) * sizeof(struct xfs_rtrefcount_key));
+}
+
+static inline xfs_rtrefcount_ptr_t *
+xfs_rtrefcount_ptr_addr(
+	struct xfs_btree_block	*block,
+	unsigned int		index,
+	unsigned int		maxrecs)
+{
+	return (xfs_rtrefcount_ptr_t *)
+		((char *)block + XFS_RTREFCOUNT_BLOCK_LEN +
+		 maxrecs * sizeof(struct xfs_rtrefcount_key) +
+		 (index - 1) * sizeof(xfs_rtrefcount_ptr_t));
+}
+
+#endif	/* __XFS_RTREFCOUNT_BTREE_H__ */
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index 098f16786e96..bd9ccaa73396 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -26,6 +26,7 @@
 #include "xfs_da_format.h"
 #include "xfs_health.h"
 #include "xfs_rtrmap_btree.h"
+#include "xfs_rtrefcount_btree.h"
 
 /*
  * Physical superblock buffer manipulations. Shared with libxfs in userspace.
@@ -873,6 +874,13 @@ xfs_sb_mount_common(
 	mp->m_refc_mnr[0] = mp->m_refc_mxr[0] / 2;
 	mp->m_refc_mnr[1] = mp->m_refc_mxr[1] / 2;
 
+	mp->m_rtrefc_mxr[0] = xfs_rtrefcountbt_maxrecs(mp, sbp->sb_blocksize,
+			true);
+	mp->m_rtrefc_mxr[1] = xfs_rtrefcountbt_maxrecs(mp, sbp->sb_blocksize,
+			false);
+	mp->m_rtrefc_mnr[0] = mp->m_rtrefc_mxr[0] / 2;
+	mp->m_rtrefc_mnr[1] = mp->m_rtrefc_mxr[1] / 2;
+
 	mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
 	mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
 	mp->m_ag_max_usable = xfs_alloc_ag_max_usable(mp);
diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
index 775c45b4561d..4232299519a7 100644
--- a/fs/xfs/libxfs/xfs_shared.h
+++ b/fs/xfs/libxfs/xfs_shared.h
@@ -30,6 +30,7 @@ extern const struct xfs_buf_ops xfs_cntbt_buf_ops;
 extern const struct xfs_buf_ops xfs_rmapbt_buf_ops;
 extern const struct xfs_buf_ops xfs_rtrmapbt_buf_ops;
 extern const struct xfs_buf_ops xfs_refcountbt_buf_ops;
+extern const struct xfs_buf_ops xfs_rtrefcountbt_buf_ops;
 extern const struct xfs_buf_ops xfs_attr3_leaf_buf_ops;
 extern const struct xfs_buf_ops xfs_attr3_rmt_buf_ops;
 extern const struct xfs_buf_ops xfs_bmbt_buf_ops;
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 15069200af12..b2838f2ad8c8 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -34,6 +34,7 @@
 #include "xfs_trace.h"
 #include "xfs_imeta.h"
 #include "xfs_rtrmap_btree.h"
+#include "xfs_rtrefcount_btree.h"
 
 static DEFINE_MUTEX(xfs_uuid_table_mutex);
 static int xfs_uuid_table_size;
@@ -801,6 +802,8 @@ xfs_mountfs(
 	mp->m_rtrmap_maxlevels = xfs_rtrmapbt_compute_maxlevels(mp,
 			mp->m_sb.sb_dblocks, mp->m_sb.sb_rblocks);
 	xfs_refcountbt_compute_maxlevels(mp);
+	mp->m_rtrefc_maxlevels = xfs_rtrefcountbt_compute_maxlevels(mp,
+			mp->m_sb.sb_dblocks, mp->m_sb.sb_rblocks);
 
 	/*
 	 * Check if sb_agblocks is aligned at stripe boundary.  If sb_agblocks
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index c83eb1401b65..ba73740a3687 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -130,11 +130,14 @@ typedef struct xfs_mount {
 	uint			m_rtrmap_mnr[2]; /* min rtrmap btree records */
 	uint			m_refc_mxr[2];	/* max refc btree records */
 	uint			m_refc_mnr[2];	/* min refc btree records */
+	uint			m_rtrefc_mxr[2]; /* max rtrefc btree records */
+	uint			m_rtrefc_mnr[2]; /* min rtrefc btree records */
 	uint			m_ag_maxlevels;	/* XFS_AG_MAXLEVELS */
 	uint			m_bm_maxlevels[2]; /* XFS_BM_MAXLEVELS */
 	uint			m_rmap_maxlevels; /* max rmap btree levels */
 	uint			m_rtrmap_maxlevels; /* max rtrmap btree level */
 	uint			m_refc_maxlevels; /* max refcount btree level */
+	uint			m_rtrefc_maxlevels; /* max rtrefc btree level */
 	xfs_extlen_t		m_ag_prealloc_blocks; /* reserved ag blocks */
 	uint			m_alloc_set_aside; /* space we can't use */
 	uint			m_ag_max_usable; /* max space per AG */
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index b261c614a958..2723133e4d83 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -43,6 +43,8 @@ xfs_check_ondisk_structs(void)
 	XFS_CHECK_STRUCT_SIZE(struct xfs_inobt_rec,		16);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_refcount_key,		4);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_refcount_rec,		12);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_rtrefcount_key,	8);
+	XFS_CHECK_STRUCT_SIZE(struct xfs_rtrefcount_rec,	20);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_rmap_key,		20);
 	XFS_CHECK_STRUCT_SIZE(struct xfs_rmap_rec,		24);
 	XFS_CHECK_STRUCT_SIZE(xfs_timestamp_t,			8);