[ovs-dev] [PATCH] ofproto-dpif: Zero-out subfacet counters when installation fails.

[Justin Pettit]

When deleting subfacets, subfacet_uninstall() asserts that the
subfacet's counters are zero to make sure we don't lose counters.  We
have seen cases where a subfacet cannot be installed, but the counters
have values.  This should not happen, since we shouldn't create a
subfacet if the datapath has a flow.  To prevent asserts, this commit
zeros out the counters and logs an error, since it's possible for a
datapath to trigger this.

Bug #18460.

Signed-off-by: Justin Pettit <jpettit at nicira.com>
---
 ofproto/ofproto-dpif.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 67e6c7a..8b216e5 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -3760,6 +3760,16 @@ handle_miss_upcalls(struct dpif_backer *backer, struct dpif_upcall *upcalls,
 
             COVERAGE_INC(subfacet_install_fail);
 
+            /* Zero-out subfacet counters when installation failed, but
+             * datapath reported hits.  This should not happen, since if
+             * the datapath flow exists, we should not be attempting to
+             * create a new subfacet. */
+            if (subfacet->dp_packet_count || subfacet->dp_byte_count) {
+                VLOG_ERR_RL(&rl, "failed to install subfacet for which "
+                            "datapath reported hits");
+                subfacet->dp_packet_count = subfacet->dp_byte_count = 0;
+            }
+
             subfacet->path = SF_NOT_INSTALLED;
         }
 
-- 
1.7.5.4