From: Sage Weil <sage@redhat.com>
Date: Fri, 17 Jul 2015 18:51:12 +0000 (-0400)
Subject: osd: allow sort order to randomly revert to nibblewise via debug config
X-Git-Tag: v9.1.0~346^2~45
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=25f0afc8735c2ccb920af720a476cfcf69affa85;p=ceph.git

osd: allow sort order to randomly revert to nibblewise via debug config

Note that this option is misused and applied to some but not all OSDs they
will disagree on the sort order and get confused, potentially losing data.
It must be global to the cluster in order to be useful.

Signed-off-by: Sage Weil <sage@redhat.com>
---

diff --git a/src/common/config_opts.h b/src/common/config_opts.h
index b21f69a788ba..ff083fb0349a 100644
--- a/src/common/config_opts.h
+++ b/src/common/config_opts.h
@@ -693,6 +693,7 @@ OPTION(osd_debug_verify_stray_on_activate, OPT_BOOL, false)
 OPTION(osd_debug_skip_full_check_in_backfill_reservation, OPT_BOOL, false)
 OPTION(osd_debug_reject_backfill_probability, OPT_DOUBLE, 0)
 OPTION(osd_debug_inject_copyfrom_error, OPT_BOOL, false)  // inject failure during copyfrom completion
+OPTION(osd_debug_randomize_hobject_sort_order, OPT_BOOL, false)
 OPTION(osd_enable_op_tracker, OPT_BOOL, true) // enable/disable OSD op tracking
 OPTION(osd_num_op_tracker_shard, OPT_U32, 32) // The number of shards for holding the ops
 OPTION(osd_op_history_size, OPT_U32, 20)    // Max number of completed ops to track
diff --git a/src/osd/PG.cc b/src/osd/PG.cc
index 628bd130023a..ef3a969caaec 100644
--- a/src/osd/PG.cc
+++ b/src/osd/PG.cc
@@ -217,7 +217,8 @@ PG::PG(OSDService *o, OSDMapRef curmap,
   pg_id(p),
   peer_features(CEPH_FEATURES_SUPPORTED_DEFAULT),
   acting_features(CEPH_FEATURES_SUPPORTED_DEFAULT),
-  upacting_features(CEPH_FEATURES_SUPPORTED_DEFAULT)
+  upacting_features(CEPH_FEATURES_SUPPORTED_DEFAULT),
+  randomly_sort_nibblewise(false)
 {
 #ifdef PG_DEBUG_REFS
   osd->add_pgid(p, this);
@@ -4730,6 +4731,15 @@ void PG::start_peering_interval(
     upacting_features &= osdmap->get_xinfo(*p).features;
   }
 
+  if (g_conf->osd_debug_randomize_hobject_sort_order) {
+    // randomly use a nibblewise sort (when we otherwise might have
+    // done bitwise) based on some *deterministic* function such that
+    // all peers/osds will agree.
+    randomly_sort_nibblewise = (info.history.same_interval_since + info.pgid.ps()) & 1;
+  } else {
+    randomly_sort_nibblewise = false;
+  }
+
   dout(10) << " up " << oldup << " -> " << up 
 	   << ", acting " << oldacting << " -> " << acting 
 	   << ", acting_primary " << old_acting_primary << " -> " << new_acting_primary
diff --git a/src/osd/PG.h b/src/osd/PG.h
index 6789872aaa8a..8e4de79de14c 100644
--- a/src/osd/PG.h
+++ b/src/osd/PG.h
@@ -2016,6 +2016,8 @@ public:
   uint64_t acting_features;
   uint64_t upacting_features;
 
+  bool randomly_sort_nibblewise;
+
  public:
   const spg_t&      get_pgid() const { return pg_id; }
   int        get_nrep() const { return acting.size(); }
@@ -2031,7 +2033,8 @@ public:
 
   /// true if we will sort hobjects bitwise for this pg interval
   bool get_sort_bitwise() const {
-    return get_min_upacting_features() & CEPH_FEATURE_OSD_BITWISE_HOBJ_SORT;
+    return (get_min_upacting_features() & CEPH_FEATURE_OSD_BITWISE_HOBJ_SORT) &&
+      !randomly_sort_nibblewise;
   }
 
   void init_primary_up_acting(