1 files changed, 37 insertions, 6 deletions

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 0ac717aad380..6d9df2e9b267 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;