diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index f4e84aa..8dd7186 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -911,6 +911,11 @@ xfs_log_sb(
 	 * reservations that have been taken out percpu counters. If we have an
 	 * unclean shutdown, this will be corrected by log recovery rebuilding
 	 * the counters from the AGF block counts.
+	 *
+	 * Do not update sb_frextents here because it is not part of the lazy
+	 * sb counters, despite having a percpu counter. It is always kept
+	 * consistent with the ondisk rtbitmap by xfs_trans_apply_sb_deltas()
+	 * and hence we don't need have to update it here.
 	 */
 	if (xfs_has_lazysbcount(mp)) {
 		mp->m_sb.sb_icount = percpu_counter_sum(&mp->m_icount);
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 68f7454..a0d7aa7 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -349,10 +349,7 @@ xfs_fs_counts(
 	cnt->freeino = percpu_counter_read_positive(&mp->m_ifree);
 	cnt->freedata = percpu_counter_read_positive(&mp->m_fdblocks) -
 						xfs_fdblocks_unavailable(mp);
-
-	spin_lock(&mp->m_sb_lock);
-	cnt->freertx = mp->m_sb.sb_frextents;
-	spin_unlock(&mp->m_sb_lock);
+	cnt->freertx = percpu_counter_read_positive(&mp->m_frextents);
 }
 
 /*
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 6c72674..f16ccc3 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1916,13 +1916,16 @@ xfs_inodegc_want_queue_rt_file(
 	struct xfs_inode	*ip)
 {
 	struct xfs_mount	*mp = ip->i_mount;
-	uint64_t		freertx;
 
 	if (!XFS_IS_REALTIME_INODE(ip))
 		return false;
 
-	freertx = READ_ONCE(mp->m_sb.sb_frextents);
-	return freertx < mp->m_low_rtexts[XFS_LOWSP_5_PCNT];
+	if (__percpu_counter_compare(&mp->m_frextents,
+				mp->m_low_rtexts[XFS_LOWSP_5_PCNT],
+				XFS_FDBLOCKS_BATCH) < 0)
+		return true;
+
+	return false;
 }
 #else
 # define xfs_inodegc_want_queue_rt_file(ip)	(false)
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 53e130f..0c0bcbd 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -1110,24 +1110,33 @@ xfs_fs_writable(
 	return true;
 }
 
+/* Adjust m_fdblocks or m_frextents. */
 int
-xfs_mod_fdblocks(
+xfs_mod_freecounter(
 	struct xfs_mount	*mp,
+	struct percpu_counter	*counter,
 	int64_t			delta,
 	bool			rsvd)
 {
 	int64_t			lcounter;
 	long long		res_used;
+	uint64_t		set_aside = 0;
 	s32			batch;
-	uint64_t		set_aside;
+	bool			has_resv_pool;
+
+	ASSERT(counter == &mp->m_fdblocks || counter == &mp->m_frextents);
+	has_resv_pool = (counter == &mp->m_fdblocks);
+	if (rsvd)
+		ASSERT(has_resv_pool);
 
 	if (delta > 0) {
 		/*
 		 * If the reserve pool is depleted, put blocks back into it
 		 * first. Most of the time the pool is full.
 		 */
-		if (likely(mp->m_resblks == mp->m_resblks_avail)) {
-			percpu_counter_add(&mp->m_fdblocks, delta);
+		if (likely(!has_resv_pool ||
+			   mp->m_resblks == mp->m_resblks_avail)) {
+			percpu_counter_add(counter, delta);
 			return 0;
 		}
 
@@ -1139,7 +1148,7 @@ xfs_mod_fdblocks(
 		} else {
 			delta -= res_used;
 			mp->m_resblks_avail = mp->m_resblks;
-			percpu_counter_add(&mp->m_fdblocks, delta);
+			percpu_counter_add(counter, delta);
 		}
 		spin_unlock(&mp->m_sb_lock);
 		return 0;
@@ -1153,7 +1162,7 @@ xfs_mod_fdblocks(
 	 * then make everything serialise as we are real close to
 	 * ENOSPC.
 	 */
-	if (__percpu_counter_compare(&mp->m_fdblocks, 2 * XFS_FDBLOCKS_BATCH,
+	if (__percpu_counter_compare(counter, 2 * XFS_FDBLOCKS_BATCH,
 				     XFS_FDBLOCKS_BATCH) < 0)
 		batch = 1;
 	else
@@ -1170,9 +1179,10 @@ xfs_mod_fdblocks(
 	 * problems (i.e. transaction abort, pagecache discards, etc.) than
 	 * slightly premature -ENOSPC.
 	 */
-	set_aside = xfs_fdblocks_unavailable(mp);
-	percpu_counter_add_batch(&mp->m_fdblocks, delta, batch);
-	if (__percpu_counter_compare(&mp->m_fdblocks, set_aside,
+	if (has_resv_pool)
+		set_aside = xfs_fdblocks_unavailable(mp);
+	percpu_counter_add_batch(counter, delta, batch);
+	if (__percpu_counter_compare(counter, set_aside,
 				     XFS_FDBLOCKS_BATCH) >= 0) {
 		/* we had space! */
 		return 0;
@@ -1183,8 +1193,8 @@ xfs_mod_fdblocks(
 	 * that took us to ENOSPC.
 	 */
 	spin_lock(&mp->m_sb_lock);
-	percpu_counter_add(&mp->m_fdblocks, -delta);
-	if (!rsvd)
+	percpu_counter_add(counter, -delta);
+	if (!has_resv_pool || !rsvd)
 		goto fdblocks_enospc;
 
 	lcounter = (long long)mp->m_resblks_avail + delta;
@@ -1201,24 +1211,6 @@ xfs_mod_fdblocks(
 	return -ENOSPC;
 }
 
-int
-xfs_mod_frextents(
-	struct xfs_mount	*mp,
-	int64_t			delta)
-{
-	int64_t			lcounter;
-	int			ret = 0;
-
-	spin_lock(&mp->m_sb_lock);
-	lcounter = mp->m_sb.sb_frextents + delta;
-	if (lcounter < 0)
-		ret = -ENOSPC;
-	else
-		mp->m_sb.sb_frextents = lcounter;
-	spin_unlock(&mp->m_sb_lock);
-	return ret;
-}
-
 /*
  * Used to free the superblock along various error paths.
  */
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index f6dc19d..a6b8efb 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -183,6 +183,8 @@ typedef struct xfs_mount {
 	struct percpu_counter	m_icount;	/* allocated inodes counter */
 	struct percpu_counter	m_ifree;	/* free inodes counter */
 	struct percpu_counter	m_fdblocks;	/* free block counter */
+	struct percpu_counter	m_frextents;	/* free rt extent counter */
+
 	/*
 	 * Count of data device blocks reserved for delayed allocations,
 	 * including indlen blocks.  Does not include allocated CoW staging
@@ -494,9 +496,20 @@ xfs_fdblocks_unavailable(
 	return mp->m_alloc_set_aside + atomic64_read(&mp->m_allocbt_blks);
 }
 
-extern int	xfs_mod_fdblocks(struct xfs_mount *mp, int64_t delta,
-				 bool reserved);
-extern int	xfs_mod_frextents(struct xfs_mount *mp, int64_t delta);
+int xfs_mod_freecounter(struct xfs_mount *mp, struct percpu_counter *counter,
+		int64_t delta, bool rsvd);
+
+static inline int
+xfs_mod_fdblocks(struct xfs_mount *mp, int64_t delta, bool reserved)
+{
+	return xfs_mod_freecounter(mp, &mp->m_fdblocks, delta, reserved);
+}
+
+static inline int
+xfs_mod_frextents(struct xfs_mount *mp, int64_t delta)
+{
+	return xfs_mod_freecounter(mp, &mp->m_frextents, delta, false);
+}
 
 extern int	xfs_readsb(xfs_mount_t *, int);
 extern void	xfs_freesb(xfs_mount_t *);
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index 76f50e7..997e4a9 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -1318,6 +1318,7 @@ xfs_rtalloc_reinit_frextents(
 	spin_lock(&mp->m_sb_lock);
 	mp->m_sb.sb_frextents = val;
 	spin_unlock(&mp->m_sb_lock);
+	percpu_counter_set(&mp->m_frextents, mp->m_sb.sb_frextents);
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 54be9d6..3a50886 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -843,9 +843,11 @@ xfs_fs_statfs(
 
 	if (XFS_IS_REALTIME_MOUNT(mp) &&
 	    (ip->i_diflags & (XFS_DIFLAG_RTINHERIT | XFS_DIFLAG_REALTIME))) {
+		s64	freertx;
+
 		statp->f_blocks = sbp->sb_rblocks;
-		statp->f_bavail = statp->f_bfree =
-			sbp->sb_frextents * sbp->sb_rextsize;
+		freertx = percpu_counter_sum_positive(&mp->m_frextents);
+		statp->f_bavail = statp->f_bfree = freertx * sbp->sb_rextsize;
 	}
 
 	return 0;
@@ -1015,8 +1017,14 @@ xfs_init_percpu_counters(
 	if (error)
 		goto free_fdblocks;
 
+	error = percpu_counter_init(&mp->m_frextents, 0, GFP_KERNEL);
+	if (error)
+		goto free_delalloc;
+
 	return 0;
 
+free_delalloc:
+	percpu_counter_destroy(&mp->m_delalloc_blks);
 free_fdblocks:
 	percpu_counter_destroy(&mp->m_fdblocks);
 free_ifree:
@@ -1033,6 +1041,7 @@ xfs_reinit_percpu_counters(
 	percpu_counter_set(&mp->m_icount, mp->m_sb.sb_icount);
 	percpu_counter_set(&mp->m_ifree, mp->m_sb.sb_ifree);
 	percpu_counter_set(&mp->m_fdblocks, mp->m_sb.sb_fdblocks);
+	percpu_counter_set(&mp->m_frextents, mp->m_sb.sb_frextents);
 }
 
 static void
@@ -1045,6 +1054,7 @@ xfs_destroy_percpu_counters(
 	ASSERT(xfs_is_shutdown(mp) ||
 	       percpu_counter_sum(&mp->m_delalloc_blks) == 0);
 	percpu_counter_destroy(&mp->m_delalloc_blks);
+	percpu_counter_destroy(&mp->m_frextents);
 }
 
 static int
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 0ac717a..6d9df2e 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -498,10 +498,31 @@ xfs_trans_apply_sb_deltas(
 			be64_add_cpu(&sbp->sb_fdblocks, tp->t_res_fdblocks_delta);
 	}
 
-	if (tp->t_frextents_delta)
-		be64_add_cpu(&sbp->sb_frextents, tp->t_frextents_delta);
-	if (tp->t_res_frextents_delta)
-		be64_add_cpu(&sbp->sb_frextents, tp->t_res_frextents_delta);
+	/*
+	 * Updating frextents requires careful handling because it does not
+	 * behave like the lazysb counters because we cannot rely on log
+	 * recovery in older kenels to recompute the value from the rtbitmap.
+	 * This means that the ondisk frextents must be consistent with the
+	 * rtbitmap.
+	 *
+	 * Therefore, log the frextents change to the ondisk superblock and
+	 * update the incore superblock so that future calls to xfs_log_sb
+	 * write the correct value ondisk.
+	 *
+	 * Don't touch m_frextents because it includes incore reservations,
+	 * and those are handled by the unreserve function.
+	 */
+	if (tp->t_frextents_delta || tp->t_res_frextents_delta) {
+		struct xfs_mount	*mp = tp->t_mountp;
+		int64_t			rtxdelta;
+
+		rtxdelta = tp->t_frextents_delta + tp->t_res_frextents_delta;
+
+		spin_lock(&mp->m_sb_lock);
+		be64_add_cpu(&sbp->sb_frextents, rtxdelta);
+		mp->m_sb.sb_frextents += rtxdelta;
+		spin_unlock(&mp->m_sb_lock);
+	}
 
 	if (tp->t_dblocks_delta) {
 		be64_add_cpu(&sbp->sb_dblocks, tp->t_dblocks_delta);
@@ -614,7 +635,12 @@ xfs_trans_unreserve_and_mod_sb(
 	if (ifreedelta)
 		percpu_counter_add(&mp->m_ifree, ifreedelta);
 
-	if (rtxdelta == 0 && !(tp->t_flags & XFS_TRANS_SB_DIRTY))
+	if (rtxdelta) {
+		error = xfs_mod_frextents(mp, rtxdelta);
+		ASSERT(!error);
+	}
+
+	if (!(tp->t_flags & XFS_TRANS_SB_DIRTY))
 		return;
 
 	/* apply remaining deltas */
@@ -622,7 +648,12 @@ xfs_trans_unreserve_and_mod_sb(
 	mp->m_sb.sb_fdblocks += tp->t_fdblocks_delta + tp->t_res_fdblocks_delta;
 	mp->m_sb.sb_icount += idelta;
 	mp->m_sb.sb_ifree += ifreedelta;
-	mp->m_sb.sb_frextents += rtxdelta;
+	/*
+	 * Do not touch sb_frextents here because we are dealing with incore
+	 * reservation.  sb_frextents is not part of the lazy sb counters so it
+	 * must be consistent with the ondisk rtbitmap and must never include
+	 * incore reservations.
+	 */
 	mp->m_sb.sb_dblocks += tp->t_dblocks_delta;
 	mp->m_sb.sb_agcount += tp->t_agcount_delta;
 	mp->m_sb.sb_imax_pct += tp->t_imaxpct_delta;