diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 776ae2f325d1e4f534540206a30a138b01c1ea46..af1a72efa64cf79f6696041a7fa409e01893aeb1 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -2264,6 +2264,7 @@ xfs_alloc_log_agf(
 		offsetof(xfs_agf_t, agf_longest),
 		offsetof(xfs_agf_t, agf_btreeblks),
 		offsetof(xfs_agf_t, agf_uuid),
+		offsetof(xfs_agf_t, agf_rmap_blocks),
 		sizeof(xfs_agf_t)
 	};
 
diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
index f814d42c73b2fb7484dd76ad024f63891de155f0..e6a8bea0f7bad219cdb98a97f2844fef293e6c92 100644
--- a/fs/xfs/libxfs/xfs_format.h
+++ b/fs/xfs/libxfs/xfs_format.h
@@ -640,12 +640,15 @@ typedef struct xfs_agf {
 	__be32		agf_btreeblks;	/* # of blocks held in AGF btrees */
 	uuid_t		agf_uuid;	/* uuid of filesystem */
 
+	__be32		agf_rmap_blocks;	/* rmapbt blocks used */
+	__be32		agf_padding;		/* padding */
+
 	/*
 	 * reserve some contiguous space for future logged fields before we add
 	 * the unlogged fields. This makes the range logging via flags and
 	 * structure offsets much simpler.
 	 */
-	__be64		agf_spare64[16];
+	__be64		agf_spare64[15];
 
 	/* unlogged fields, written during buffer writeback. */
 	__be64		agf_lsn;	/* last write sequence */
@@ -670,7 +673,8 @@ typedef struct xfs_agf {
 #define	XFS_AGF_LONGEST		0x00000400
 #define	XFS_AGF_BTREEBLKS	0x00000800
 #define	XFS_AGF_UUID		0x00001000
-#define	XFS_AGF_NUM_BITS	13
+#define	XFS_AGF_RMAP_BLOCKS	0x00002000
+#define	XFS_AGF_NUM_BITS	14
 #define	XFS_AGF_ALL_BITS	((1 << XFS_AGF_NUM_BITS) - 1)
 
 #define XFS_AGF_FLAGS \
@@ -686,7 +690,8 @@ typedef struct xfs_agf {
 	{ XFS_AGF_FREEBLKS,	"FREEBLKS" }, \
 	{ XFS_AGF_LONGEST,	"LONGEST" }, \
 	{ XFS_AGF_BTREEBLKS,	"BTREEBLKS" }, \
-	{ XFS_AGF_UUID,		"UUID" }
+	{ XFS_AGF_UUID,		"UUID" }, \
+	{ XFS_AGF_RMAP_BLOCKS,	"RMAP_BLOCKS" }
 
 /* disk block (xfs_daddr_t) in the AG */
 #define XFS_AGF_DADDR(mp)	((xfs_daddr_t)(1 << (mp)->m_sectbb_log))
diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
index bc1faebc84eccdf658ec177029beb3b4d84455b6..17b8eeb34ac89ffb9260d7ac1c3cf342148eb1da 100644
--- a/fs/xfs/libxfs/xfs_rmap_btree.c
+++ b/fs/xfs/libxfs/xfs_rmap_btree.c
@@ -98,6 +98,8 @@ xfs_rmapbt_alloc_block(
 	union xfs_btree_ptr	*new,
 	int			*stat)
 {
+	struct xfs_buf		*agbp = cur->bc_private.a.agbp;
+	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
 	int			error;
 	xfs_agblock_t		bno;
 
@@ -124,6 +126,8 @@ xfs_rmapbt_alloc_block(
 
 	xfs_trans_agbtree_delta(cur->bc_tp, 1);
 	new->s = cpu_to_be32(bno);
+	be32_add_cpu(&agf->agf_rmap_blocks, 1);
+	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
 
 	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
 	*stat = 1;
@@ -143,6 +147,8 @@ xfs_rmapbt_free_block(
 	bno = xfs_daddr_to_agbno(cur->bc_mp, XFS_BUF_ADDR(bp));
 	trace_xfs_rmapbt_free_block(cur->bc_mp, cur->bc_private.a.agno,
 			bno, 1);
+	be32_add_cpu(&agf->agf_rmap_blocks, -1);
+	xfs_alloc_log_agf(cur->bc_tp, agbp, XFS_AGF_RMAP_BLOCKS);
 	error = xfs_alloc_put_freelist(cur->bc_tp, agbp, NULL, bno, 1);
 	if (error)
 		return error;
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 0f96847b90e1175d2c6d0f497fe278e67f95e141..0b7f986745c17ff044a4d230329db1951837759a 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -248,6 +248,7 @@ xfs_growfs_data_private(
 			agf->agf_roots[XFS_BTNUM_RMAPi] =
 						cpu_to_be32(XFS_RMAP_BLOCK(mp));
 			agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
+			agf->agf_rmap_blocks = cpu_to_be32(1);
 		}
 
 		agf->agf_flfirst = cpu_to_be32(1);