From e0b90d93c43b9418259fb02d6d3a93b53944da8d Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Mon, 13 Mar 2017 11:57:44 -0400
Subject: [PATCH] osd/OSDMap: clean up primary selection

_pg_to_raw_osds was selecting a primary, but it was generally
getting thrown out since _raw_to_up_osds was picking a *new*
primary after filtering out down and nonexistent osds.  Add a
_pick_primary helper to do it and call that explicitly in the
callers where it can be used by all.

Signed-off-by: Sage Weil <sage@redhat.com>
---
 src/osd/OSDMap.cc | 40 +++++++++++++++++++++++-----------------
 src/osd/OSDMap.h  |  6 ++++--
 2 files changed, 27 insertions(+), 19 deletions(-)

diff --git a/src/osd/OSDMap.cc b/src/osd/OSDMap.cc
index b2de7fbcaf389..16945a289552f 100644
--- a/src/osd/OSDMap.cc
+++ b/src/osd/OSDMap.cc
@@ -1592,7 +1592,7 @@ void OSDMap::_remove_nonexistent_osds(const pg_pool_t& pool,
 
 int OSDMap::_pg_to_raw_osds(
   const pg_pool_t& pool, pg_t pg,
-  vector<int> *osds, int *primary,
+  vector<int> *osds,
   ps_t *ppps) const
 {
   // map to osds[]
@@ -1606,41 +1606,43 @@ int OSDMap::_pg_to_raw_osds(
 
   _remove_nonexistent_osds(pool, *osds);
 
-  *primary = -1;
-  for (unsigned i = 0; i < osds->size(); ++i) {
-    if ((*osds)[i] != CRUSH_ITEM_NONE) {
-      *primary = (*osds)[i];
-      break;
-    }
-  }
   if (ppps)
     *ppps = pps;
 
   return osds->size();
 }
 
+int OSDMap::_pick_primary(const vector<int>& osds) const
+{
+  for (auto osd : osds) {
+    if (osd != CRUSH_ITEM_NONE) {
+      return osd;
+    }
+  }
+  return -1;
+}
+
 // pg -> (up osd list)
 void OSDMap::_raw_to_up_osds(const pg_pool_t& pool, const vector<int>& raw,
-                             vector<int> *up, int *primary) const
+                             vector<int> *up) const
 {
   if (pool.can_shift_osds()) {
     // shift left
     up->clear();
+    up->reserve(raw.size());
     for (unsigned i=0; i<raw.size(); i++) {
       if (!exists(raw[i]) || is_down(raw[i]))
 	continue;
       up->push_back(raw[i]);
     }
-    *primary = (up->empty() ? -1 : up->front());
   } else {
     // set down/dne devices to NONE
-    *primary = -1;
     up->resize(raw.size());
     for (int i = raw.size() - 1; i >= 0; --i) {
       if (!exists(raw[i]) || is_down(raw[i])) {
 	(*up)[i] = CRUSH_ITEM_NONE;
       } else {
-	*primary = (*up)[i] = raw[i];
+	(*up)[i] = raw[i];
       }
     }
   }
@@ -1741,7 +1743,9 @@ int OSDMap::pg_to_raw_osds(pg_t pg, vector<int> *raw, int *primary) const
   const pg_pool_t *pool = get_pg_pool(pg.pool());
   if (!pool)
     return 0;
-  int r = _pg_to_raw_osds(*pool, pg, raw, primary, NULL);
+  int r = _pg_to_raw_osds(*pool, pg, raw, NULL);
+  if (primary)
+    *primary = _pick_primary(*raw);
   return r;
 }
 
@@ -1757,8 +1761,9 @@ void OSDMap::pg_to_raw_up(pg_t pg, vector<int> *up, int *primary) const
   }
   vector<int> raw;
   ps_t pps;
-  _pg_to_raw_osds(*pool, pg, &raw, primary, &pps);
-  _raw_to_up_osds(*pool, raw, up, primary);
+  _pg_to_raw_osds(*pool, pg, &raw, &pps);
+  _raw_to_up_osds(*pool, raw, up);
+  *primary = _pick_primary(raw);
   _apply_primary_affinity(pps, *pool, up, primary);
 }
   
@@ -1788,8 +1793,9 @@ void OSDMap::_pg_to_up_acting_osds(
   ps_t pps;
   _get_temp_osds(*pool, pg, &_acting, &_acting_primary);
   if (_acting.empty() || up || up_primary) {
-    _pg_to_raw_osds(*pool, pg, &raw, &_up_primary, &pps);
-    _raw_to_up_osds(*pool, raw, &_up, &_up_primary);
+    _pg_to_raw_osds(*pool, pg, &raw, &pps);
+    _raw_to_up_osds(*pool, raw, &_up);
+    _up_primary = _pick_primary(_up);
     _apply_primary_affinity(pps, *pool, &_up, &_up_primary);
     if (_acting.empty()) {
       _acting = _up;
diff --git a/src/osd/OSDMap.h b/src/osd/OSDMap.h
index 88eeec334618f..21bcacc0750c9 100644
--- a/src/osd/OSDMap.h
+++ b/src/osd/OSDMap.h
@@ -647,8 +647,9 @@ private:
   /// pg -> (raw osd list)
   int _pg_to_raw_osds(
     const pg_pool_t& pool, pg_t pg,
-    vector<int> *osds, int *primary,
+    vector<int> *osds,
     ps_t *ppps) const;
+  int _pick_primary(const vector<int>& osds) const;
   void _remove_nonexistent_osds(const pg_pool_t& pool, vector<int>& osds) const;
 
   void _apply_primary_affinity(ps_t seed, const pg_pool_t& pool,
@@ -656,7 +657,8 @@ private:
 
   /// pg -> (up osd list)
   void _raw_to_up_osds(const pg_pool_t& pool, const vector<int>& raw,
-                       vector<int> *up, int *primary) const;
+                       vector<int> *up) const;
+
 
   /**
    * Get the pg and primary temp, if they are specified.
-- 
2.39.5