cluster/afr: Keep child-up until ping-event

Problem:
If we have 2 bricks, brick-A and brick-B with brick-A within halo-max-latency
and brick-B more than halo-max-latency. If we set both halo-min, halo-max replicas
as '1'. In this case, brick-A comes online and then ping-latency will be updated for it.
When brick-B comes online, we have 2 up-bricks, so the code tries to find the brick with
worst latency to mark it down. Since Brick-B just came online it always had '0' latency
so brick-B used to be marked offline and Brick-B would eventually be the one to be
online even when brick-A is more suited.

Fix:
Consider latency of just-up child as HALO_MAX_LATENCY so that worst-child until
ping-latency is found as the just-up brick. Also keep ping-latency as -1 until
child-up during initialization.

BUG: 1567881
fixes bz#1567881
Change-Id: I148262fe505468190f0eb99225d0f6d57cdb6f04
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/xlators/cluster/afr/src/afr.c b/xlators/cluster/afr/src/afr.c
index ad5446191ec..cb4b1537984 100644
--- a/xlators/cluster/afr/src/afr.c
+++ b/xlators/cluster/afr/src/afr.c
@@ -534,6 +534,10 @@ init (xlator_t *this)
                 ret = -ENOMEM;
                 goto out;
         }
+        /*Initialize to -ve ping timeout so that they are not considered
+         * in child-up events until ping-event comes*/
+        for (i = 0; i < child_count; i++)
+                priv->child_latency[i] = -1;
 
         priv->children = GF_CALLOC (sizeof (xlator_t *), child_count,
                                     gf_afr_mt_xlator_t);
@@ -773,7 +777,7 @@ struct volume_options options[] = {
         { .key   = {"halo-max-latency"},
           .type  = GF_OPTION_TYPE_INT,
           .min   = 1,
-          .max   = 99999,
+          .max   = AFR_HALO_MAX_LATENCY,
           .default_value = "5",
           .op_version = {GD_OP_VERSION_3_11_0},
           .flags = OPT_FLAG_CLIENT_OPT | OPT_FLAG_SETTABLE | OPT_FLAG_DOC,