cluster/afr: Choose local child as source if possible

It is better to choose local brick as source if possible to prevent
over the wire read thus saving on bandwidth. Also changed code to not
attempt data-heal if 'source' is selected as arbiter.

Change-Id: I9a328d0198422280b13a30ab99545370a301dfea
BUG: 1314150
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/13585
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Tested-by: Krutika Dhananjay <kdhananj@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/xlators/cluster/afr/src/afr-self-heal-common.c b/xlators/cluster/afr/src/afr-self-heal-common.c
index 74e1a444069..f12ce81b0ee 100644
--- a/xlators/cluster/afr/src/afr-self-heal-common.c
+++ b/xlators/cluster/afr/src/afr-self-heal-common.c
@@ -1532,3 +1532,32 @@ afr_throttled_selfheal (call_frame_t *frame, xlator_t *this)
                                       "pending, background self-heal rejected.");
         }
 }
+
+int
+afr_choose_source_by_policy (afr_private_t *priv, unsigned char *sources,
+                             afr_transaction_type type)
+{
+        int source = -1;
+        int i      = 0;
+
+        /* Give preference to local child to save on bandwidth */
+        for (i = 0; i < priv->child_count; i++) {
+                if (priv->local[i] && sources[i]) {
+                        if ((type == AFR_DATA_TRANSACTION) &&
+                            AFR_IS_ARBITER_BRICK (priv, i))
+                                continue;
+
+                        source = i;
+                        goto out;
+                }
+        }
+
+        for (i = 0; i < priv->child_count; i++) {
+                if (sources[i]) {
+                        source = i;
+                        goto out;
+                }
+        }
+out:
+        return source;
+}