diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
index e3ae0f2b4294..adf770f0d011 100644
--- a/fs/xfs/libxfs/xfs_ag_resv.c
+++ b/fs/xfs/libxfs/xfs_ag_resv.c
@@ -38,6 +38,7 @@
 #include "xfs_trans_space.h"
 #include "xfs_rmap_btree.h"
 #include "xfs_btree.h"
+#include "xfs_refcount_btree.h"
 
 /*
  * Per-AG Block Reservations
@@ -228,6 +229,11 @@ xfs_ag_resv_init(
 	if (pag->pag_meta_resv.ar_asked == 0) {
 		ask = used = 0;
 
+		error = xfs_refcountbt_calc_reserves(pag->pag_mount,
+				pag->pag_agno, &ask, &used);
+		if (error)
+			goto out;
+
 		error = __xfs_ag_resv_init(pag, XFS_AG_RESV_METADATA,
 				ask, used);
 		if (error)
@@ -238,6 +244,11 @@ xfs_ag_resv_init(
 	if (pag->pag_agfl_resv.ar_asked == 0) {
 		ask = used = 0;
 
+		error = xfs_rmapbt_calc_reserves(pag->pag_mount, pag->pag_agno,
+				&ask, &used);
+		if (error)
+			goto out;
+
 		error = __xfs_ag_resv_init(pag, XFS_AG_RESV_AGFL, ask, used);
 		if (error)
 			goto out;
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
index 81d58b09af71..453bb2757ec2 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.c
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -79,6 +79,8 @@ xfs_refcountbt_alloc_block(
 	struct xfs_alloc_arg	args;		/* block allocation args */
 	int			error;		/* error return value */
 
+	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
+
 	memset(&args, 0, sizeof(args));
 	args.tp = cur->bc_tp;
 	args.mp = cur->bc_mp;
@@ -88,6 +90,7 @@ xfs_refcountbt_alloc_block(
 	args.firstblock = args.fsbno;
 	xfs_rmap_ag_owner(&args.oinfo, XFS_RMAP_OWN_REFC);
 	args.minlen = args.maxlen = args.prod = 1;
+	args.resv = XFS_AG_RESV_METADATA;
 
 	error = xfs_alloc_vextent(&args);
 	if (error)
@@ -125,16 +128,19 @@ xfs_refcountbt_free_block(
 	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
 	xfs_fsblock_t		fsbno = XFS_DADDR_TO_FSB(mp, XFS_BUF_ADDR(bp));
 	struct xfs_owner_info	oinfo;
+	int			error;
 
 	trace_xfs_refcountbt_free_block(cur->bc_mp, cur->bc_private.a.agno,
 			XFS_FSB_TO_AGBNO(cur->bc_mp, fsbno), 1);
 	xfs_rmap_ag_owner(&oinfo, XFS_RMAP_OWN_REFC);
 	be32_add_cpu(&agf->agf_refcount_blocks, -1);
 	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_REFCOUNT_BLOCKS);
-	xfs_bmap_add_free(mp, cur->bc_private.a.dfops, fsbno, 1,
-			&oinfo);
+	error = xfs_free_extent(cur->bc_tp, fsbno, 1, &oinfo,
+			XFS_AG_RESV_METADATA);
+	if (error)
+		return error;
 
-	return 0;
+	return error;
 }
 
 STATIC int
@@ -387,3 +393,59 @@ xfs_refcountbt_compute_maxlevels(
 	mp->m_refc_maxlevels = xfs_btree_compute_maxlevels(mp,
 			mp->m_refc_mnr, mp->m_sb.sb_agblocks);
 }
+
+/* Calculate the refcount btree size for some records. */
+xfs_extlen_t
+xfs_refcountbt_calc_size(
+	struct xfs_mount	*mp,
+	unsigned long long	len)
+{
+	return xfs_btree_calc_size(mp, mp->m_refc_mnr, len);
+}
+
+/*
+ * Calculate the maximum refcount btree size.
+ */
+xfs_extlen_t
+xfs_refcountbt_max_size(
+	struct xfs_mount	*mp)
+{
+	/* Bail out if we're uninitialized, which can happen in mkfs. */
+	if (mp->m_refc_mxr[0] == 0)
+		return 0;
+
+	return xfs_refcountbt_calc_size(mp, mp->m_sb.sb_agblocks);
+}
+
+/*
+ * Figure out how many blocks to reserve and how many are used by this btree.
+ */
+int
+xfs_refcountbt_calc_reserves(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno,
+	xfs_extlen_t		*ask,
+	xfs_extlen_t		*used)
+{
+	struct xfs_buf		*agbp;
+	struct xfs_agf		*agf;
+	xfs_extlen_t		tree_len;
+	int			error;
+
+	if (!xfs_sb_version_hasreflink(&mp->m_sb))
+		return 0;
+
+	*ask += xfs_refcountbt_max_size(mp);
+
+	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+	if (error)
+		return error;
+
+	agf = XFS_BUF_TO_AGF(agbp);
+	tree_len = be32_to_cpu(agf->agf_refcount_blocks);
+	xfs_buf_relse(agbp);
+
+	*used += tree_len;
+
+	return error;
+}
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.h b/fs/xfs/libxfs/xfs_refcount_btree.h
index 9e9ad7c6d267..3be7768bd51a 100644
--- a/fs/xfs/libxfs/xfs_refcount_btree.h
+++ b/fs/xfs/libxfs/xfs_refcount_btree.h
@@ -64,4 +64,11 @@ extern int xfs_refcountbt_maxrecs(struct xfs_mount *mp, int blocklen,
 		bool leaf);
 extern void xfs_refcountbt_compute_maxlevels(struct xfs_mount *mp);
 
+extern xfs_extlen_t xfs_refcountbt_calc_size(struct xfs_mount *mp,
+		unsigned long long len);
+extern xfs_extlen_t xfs_refcountbt_max_size(struct xfs_mount *mp);
+
+extern int xfs_refcountbt_calc_reserves(struct xfs_mount *mp,
+		xfs_agnumber_t agno, xfs_extlen_t *ask, xfs_extlen_t *used);
+
 #endif	/* __XFS_REFCOUNT_BTREE_H__ */
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index 9c0585e7db1f..83e672ff7577 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -35,6 +35,7 @@
 #include "xfs_cksum.h"
 #include "xfs_error.h"
 #include "xfs_extent_busy.h"
+#include "xfs_ag_resv.h"
 
 /*
  * Reverse map btree.
@@ -533,3 +534,62 @@ xfs_rmapbt_compute_maxlevels(
 		mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels(mp,
 				mp->m_rmap_mnr, mp->m_sb.sb_agblocks);
 }
+
+/* Calculate the refcount btree size for some records. */
+xfs_extlen_t
+xfs_rmapbt_calc_size(
+	struct xfs_mount	*mp,
+	unsigned long long	len)
+{
+	return xfs_btree_calc_size(mp, mp->m_rmap_mnr, len);
+}
+
+/*
+ * Calculate the maximum refcount btree size.
+ */
+xfs_extlen_t
+xfs_rmapbt_max_size(
+	struct xfs_mount	*mp)
+{
+	/* Bail out if we're uninitialized, which can happen in mkfs. */
+	if (mp->m_rmap_mxr[0] == 0)
+		return 0;
+
+	return xfs_rmapbt_calc_size(mp, mp->m_sb.sb_agblocks);
+}
+
+/*
+ * Figure out how many blocks to reserve and how many are used by this btree.
+ */
+int
+xfs_rmapbt_calc_reserves(
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno,
+	xfs_extlen_t		*ask,
+	xfs_extlen_t		*used)
+{
+	struct xfs_buf		*agbp;
+	struct xfs_agf		*agf;
+	xfs_extlen_t		pool_len;
+	xfs_extlen_t		tree_len;
+	int			error;
+
+	if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
+		return 0;
+
+	/* Reserve 1% of the AG or enough for 1 block per record. */
+	pool_len = max(mp->m_sb.sb_agblocks / 100, xfs_rmapbt_max_size(mp));
+	*ask += pool_len;
+
+	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+	if (error)
+		return error;
+
+	agf = XFS_BUF_TO_AGF(agbp);
+	tree_len = be32_to_cpu(agf->agf_rmap_blocks);
+	xfs_buf_relse(agbp);
+
+	*used += tree_len;
+
+	return error;
+}
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
index e73a55357dab..2a9ac472fb15 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.h
+++ b/fs/xfs/libxfs/xfs_rmap_btree.h
@@ -58,4 +58,11 @@ struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct xfs_mount *mp,
 int xfs_rmapbt_maxrecs(struct xfs_mount *mp, int blocklen, int leaf);
 extern void xfs_rmapbt_compute_maxlevels(struct xfs_mount *mp);
 
+extern xfs_extlen_t xfs_rmapbt_calc_size(struct xfs_mount *mp,
+		unsigned long long len);
+extern xfs_extlen_t xfs_rmapbt_max_size(struct xfs_mount *mp);
+
+extern int xfs_rmapbt_calc_reserves(struct xfs_mount *mp,
+		xfs_agnumber_t agno, xfs_extlen_t *ask, xfs_extlen_t *used);
+
 #endif	/* __XFS_RMAP_BTREE_H__ */
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 3acbf4e03187..93d12fa2670d 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -43,6 +43,7 @@
 #include "xfs_log.h"
 #include "xfs_filestream.h"
 #include "xfs_rmap.h"
+#include "xfs_ag_resv.h"
 
 /*
  * File system operations
@@ -630,6 +631,11 @@ xfs_growfs_data_private(
 	xfs_set_low_space_thresholds(mp);
 	mp->m_alloc_set_aside = xfs_alloc_set_aside(mp);
 
+	/* Reserve AG metadata blocks. */
+	error = xfs_fs_reserve_ag_blocks(mp);
+	if (error && error != -ENOSPC)
+		goto out;
+
 	/* update secondary superblocks. */
 	for (agno = 1; agno < nagcount; agno++) {
 		error = 0;
@@ -680,6 +686,8 @@ xfs_growfs_data_private(
 			continue;
 		}
 	}
+
+ out:
 	return saved_error ? saved_error : error;
 
  error0:
@@ -989,3 +997,59 @@ xfs_do_force_shutdown(
 	"Please umount the filesystem and rectify the problem(s)");
 	}
 }
+
+/*
+ * Reserve free space for per-AG metadata.
+ */
+int
+xfs_fs_reserve_ag_blocks(
+	struct xfs_mount	*mp)
+{
+	xfs_agnumber_t		agno;
+	struct xfs_perag	*pag;
+	int			error = 0;
+	int			err2;
+
+	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
+		pag = xfs_perag_get(mp, agno);
+		err2 = xfs_ag_resv_init(pag);
+		xfs_perag_put(pag);
+		if (err2 && !error)
+			error = err2;
+	}
+
+	if (error && error != -ENOSPC) {
+		xfs_warn(mp,
+	"Error %d reserving per-AG metadata reserve pool.", error);
+		xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+	}
+
+	return error;
+}
+
+/*
+ * Free space reserved for per-AG metadata.
+ */
+int
+xfs_fs_unreserve_ag_blocks(
+	struct xfs_mount	*mp)
+{
+	xfs_agnumber_t		agno;
+	struct xfs_perag	*pag;
+	int			error = 0;
+	int			err2;
+
+	for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
+		pag = xfs_perag_get(mp, agno);
+		err2 = xfs_ag_resv_free(pag);
+		xfs_perag_put(pag);
+		if (err2 && !error)
+			error = err2;
+	}
+
+	if (error)
+		xfs_warn(mp,
+	"Error %d freeing per-AG metadata reserve pool.", error);
+
+	return error;
+}
diff --git a/fs/xfs/xfs_fsops.h b/fs/xfs/xfs_fsops.h
index f32713f14f9a..f34915898fea 100644
--- a/fs/xfs/xfs_fsops.h
+++ b/fs/xfs/xfs_fsops.h
@@ -26,4 +26,7 @@ extern int xfs_reserve_blocks(xfs_mount_t *mp, __uint64_t *inval,
 				xfs_fsop_resblks_t *outval);
 extern int xfs_fs_goingdown(xfs_mount_t *mp, __uint32_t inflags);
 
+extern int xfs_fs_reserve_ag_blocks(struct xfs_mount *mp);
+extern int xfs_fs_unreserve_ag_blocks(struct xfs_mount *mp);
+
 #endif	/* __XFS_FSOPS_H__ */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 099c00ecb078..40fedc00b30d 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -995,10 +995,17 @@ xfs_mountfs(
 			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
 			goto out_quota;
 		}
+
+		/* Reserve AG blocks for future btree expansion. */
+		error = xfs_fs_reserve_ag_blocks(mp);
+		if (error && error != -ENOSPC)
+			goto out_agresv;
 	}
 
 	return 0;
 
+ out_agresv:
+	xfs_fs_unreserve_ag_blocks(mp);
  out_quota:
 	xfs_qm_unmount_quotas(mp);
  out_rtunmount:
@@ -1043,6 +1050,7 @@ xfs_unmountfs(
 
 	cancel_delayed_work_sync(&mp->m_eofblocks_work);
 
+	xfs_fs_unreserve_ag_blocks(mp);
 	xfs_qm_unmount_quotas(mp);
 	xfs_rtunmount_inodes(mp);
 	IRELE(mp->m_rootip);
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index c32e7e61e7f3..90a8fd724abb 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1325,10 +1325,22 @@ xfs_fs_remount(
 			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
 			return error;
 		}
+
+		/* Create the per-AG metadata reservation pool .*/
+		error = xfs_fs_reserve_ag_blocks(mp);
+		if (error && error != -ENOSPC)
+			return error;
 	}
 
 	/* rw -> ro */
 	if (!(mp->m_flags & XFS_MOUNT_RDONLY) && (*flags & MS_RDONLY)) {
+		/* Free the per-AG metadata reservation pool. */
+		error = xfs_fs_unreserve_ag_blocks(mp);
+		if (error) {
+			xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+			return error;
+		}
+
 		/*
 		 * Before we sync the metadata, we need to free up the reserve
 		 * block pool so that the used block count in the superblock on