cfm: Log fault status changes more informatively.

Until now, fault status changes just log the new status.  This means that
the administrator has to find two consecutive status change messages to
see what actually changed.

This commit changes the log message format to prefix new faults with '+'
and faults that disappeared with '-'.  Existing faults that are still
present are not prefixed.

This also simplifies the code a little by making ds_put_cfm_fault()
put spaces before fault names instead of after.

Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/lib/cfm.c b/lib/cfm.c
index d0ae55d1acb62f2fdb761dd22ead4c871ace78b8..66bca75c67d58361fe7e65b1fd73c2f3f27ee942 100644 (file)
--- a/lib/cfm.c
+++ b/lib/cfm.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010, 2011 Nicira Networks.
+ * Copyright (c) 2010, 2011, 2012 Nicira Networks.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -159,22 +159,21 @@ cfm_fault_reason_to_str(int reason) {
 }
 
 static void
-ds_put_cfm_fault(struct ds *ds, int fault)
+ds_put_cfm_fault(struct ds *ds, int old_fault, int new_fault)
 {
-    size_t length = ds->length;
     int i;
 
     for (i = 0; i < CFM_FAULT_N_REASONS; i++) {
         int reason = 1 << i;
 
-        if (fault & reason) {
-            ds_put_format(ds, "%s ", cfm_fault_reason_to_str(reason));
+        if ((old_fault | new_fault) & reason) {
+            ds_put_format(ds, " %s%s",
+                          (!(old_fault & reason) ? "+"
+                           : !(new_fault & reason) ? "-"
+                           : ""),
+                          cfm_fault_reason_to_str(reason));
         }
     }
-
-    if (ds->length > length) {
-        ds_truncate(ds, ds->length - 1);
-    }
 }
 
 static void
@@ -398,8 +397,8 @@ cfm_run(struct cfm *cfm)
         if (old_cfm_fault != cfm->fault) {
             struct ds ds = DS_EMPTY_INITIALIZER;
 
-            ds_put_cfm_fault(&ds, cfm->fault);
-            VLOG_INFO_RL(&rl, "%s: CFM fault status changed: %s", cfm->name,
+            ds_put_cfm_fault(&ds, old_cfm_fault, cfm->fault);
+            VLOG_INFO_RL(&rl, "%s: CFM fault status changed:%s", cfm->name,
                          ds_cstr_ro(&ds));
             ds_destroy(&ds);
         }
@@ -702,16 +701,17 @@ static void
 cfm_print_details(struct ds *ds, const struct cfm *cfm)
 {
     struct remote_mp *rmp;
+    int fault;
 
     ds_put_format(ds, "---- %s ----\n", cfm->name);
     ds_put_format(ds, "MPID %"PRIu64":%s%s\n", cfm->mpid,
                   cfm->extended ? " extended" : "",
                   cfm->fault_override >= 0 ? " fault_override" : "");
 
-
-    if (cfm_get_fault(cfm)) {
-        ds_put_cstr(ds, "\tfault: ");
-        ds_put_cfm_fault(ds, cfm_get_fault(cfm));
+    fault = cfm_get_fault(cfm);
+    if (fault) {
+        ds_put_cstr(ds, "\tfault:");
+        ds_put_cfm_fault(ds, fault, fault);
         ds_put_cstr(ds, "\n");
     }