1 files changed, 35 insertions, 13 deletions

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 6af2396a317c..c6c62321dfd6 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -978,10 +978,10 @@ static void set_rgrp_preferences(struct gfs2_sbd *sdp)
 		rgd->rd_flags |= GFS2_RDF_PREFERRED;
 		for (i = 0; i < sdp->sd_journals; i++) {
 			rgd = gfs2_rgrpd_get_next(rgd);
-			if (rgd == first)
+			if (!rgd || rgd == first)
 				break;
 		}
-	} while (rgd != first);
+	} while (rgd && rgd != first);
 }
 
 /**
@@ -1244,14 +1244,13 @@ int gfs2_rgrp_go_lock(struct gfs2_holder *gh)
 }
 
 /**
- * gfs2_rgrp_go_unlock - Release RG bitmaps read in with gfs2_rgrp_bh_get()
- * @gh: The glock holder for the resource group
+ * gfs2_rgrp_brelse - Release RG bitmaps read in with gfs2_rgrp_bh_get()
+ * @rgd: The resource group
  *
  */
 
-void gfs2_rgrp_go_unlock(struct gfs2_holder *gh)
+void gfs2_rgrp_brelse(struct gfs2_rgrpd *rgd)
 {
-	struct gfs2_rgrpd *rgd = gh->gh_gl->gl_object;
 	int x, length = rgd->rd_length;
 
 	for (x = 0; x < length; x++) {
@@ -1264,6 +1263,22 @@ void gfs2_rgrp_go_unlock(struct gfs2_holder *gh)
 
 }
 
+/**
+ * gfs2_rgrp_go_unlock - Unlock a rgrp glock
+ * @gh: The glock holder for the resource group
+ *
+ */
+
+void gfs2_rgrp_go_unlock(struct gfs2_holder *gh)
+{
+	struct gfs2_rgrpd *rgd = gh->gh_gl->gl_object;
+	int demote_requested = test_bit(GLF_DEMOTE, &gh->gh_gl->gl_flags) |
+		test_bit(GLF_PENDING_DEMOTE, &gh->gh_gl->gl_flags);
+
+	if (rgd && demote_requested)
+		gfs2_rgrp_brelse(rgd);
+}
+
 int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
 			     struct buffer_head *bh,
 			     const struct gfs2_bitmap *bi, unsigned minlen, u64 *ptrimmed)
@@ -1711,10 +1726,8 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 		return ret;
 
 bitmap_full:	/* Mark bitmap as full and fall through */
-		if ((state == GFS2_BLKST_FREE) && initial_offset == 0) {
-			struct gfs2_bitmap *bi = rbm_bi(rbm);
+		if ((state == GFS2_BLKST_FREE) && initial_offset == 0)
 			set_bit(GBF_FULL, &bi->bi_flags);
-		}
 
 next_bitmap:	/* Find next bitmap in the rgrp */
 		rbm->offset = 0;
@@ -1850,14 +1863,23 @@ static bool gfs2_rgrp_congested(const struct gfs2_rgrpd *rgd, int loops)
 	const struct gfs2_sbd *sdp = gl->gl_sbd;
 	struct gfs2_lkstats *st;
 	s64 r_dcount, l_dcount;
-	s64 r_srttb, l_srttb;
+	s64 l_srttb, a_srttb = 0;
 	s64 srttb_diff;
 	s64 sqr_diff;
 	s64 var;
+	int cpu, nonzero = 0;
 
 	preempt_disable();
+	for_each_present_cpu(cpu) {
+		st = &per_cpu_ptr(sdp->sd_lkstats, cpu)->lkstats[LM_TYPE_RGRP];
+		if (st->stats[GFS2_LKS_SRTTB]) {
+			a_srttb += st->stats[GFS2_LKS_SRTTB];
+			nonzero++;
+		}
+	}
 	st = &this_cpu_ptr(sdp->sd_lkstats)->lkstats[LM_TYPE_RGRP];
-	r_srttb = st->stats[GFS2_LKS_SRTTB];
+	if (nonzero)
+		do_div(a_srttb, nonzero);
 	r_dcount = st->stats[GFS2_LKS_DCOUNT];
 	var = st->stats[GFS2_LKS_SRTTVARB] +
 	      gl->gl_stats.stats[GFS2_LKS_SRTTVARB];
@@ -1866,10 +1888,10 @@ static bool gfs2_rgrp_congested(const struct gfs2_rgrpd *rgd, int loops)
 	l_srttb = gl->gl_stats.stats[GFS2_LKS_SRTTB];
 	l_dcount = gl->gl_stats.stats[GFS2_LKS_DCOUNT];
 
-	if ((l_dcount < 1) || (r_dcount < 1) || (r_srttb == 0))
+	if ((l_dcount < 1) || (r_dcount < 1) || (a_srttb == 0))
 		return false;
 
-	srttb_diff = r_srttb - l_srttb;
+	srttb_diff = a_srttb - l_srttb;
 	sqr_diff = srttb_diff * srttb_diff;
 
 	var *= 2;