osd/OSD: improve var naming identify_splits_and_merges

Avoid p,q usage

Signed-off-by: Matan Breizman <mbreizma@redhat.com>

diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index 49c2a37630ef2b612b116f36477c281ed6709ba6..4c538b5948677e2a38217f002baa4c3c86c03253 100644 (file)
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -348,15 +348,16 @@ void OSDService::identify_splits_and_merges(
     return;
   }
   int old_pgnum = old_map->get_pg_num(pgid.pool());
-  auto p = osd->pg_num_history.pg_nums.find(pgid.pool());
-  if (p == osd->pg_num_history.pg_nums.end()) {
+  if (!osd->pg_num_history.pg_nums.contains(pgid.pool())) {
     dout(20) << __func__ << " " << pgid << " pool " << pgid.pool()
             << " has no history" << dendl;
     return;
   }
+  // The pgid's pool [epoch -> pg_num] map
+  const auto& pool_pg_num_history_map = osd->pg_num_history.pg_nums[pgid.pool()];
   dout(20) << __func__ << " " << pgid << " e" << old_map->get_epoch()
           << " to e" << new_map->get_epoch()
-          << " pg_nums " << p->second << dendl;
+          << " pg_nums " << pool_pg_num_history_map << dendl;
   deque<spg_t> queue;
   queue.push_back(pgid);
   set<spg_t> did;
@@ -365,83 +366,87 @@ void OSDService::identify_splits_and_merges(
     queue.pop_front();
     did.insert(cur);
     unsigned pgnum = old_pgnum;
-    for (auto q = p->second.lower_bound(old_map->get_epoch());
-        q != p->second.end() &&
-          q->first <= new_map->get_epoch();
-        ++q) {
-      if (pgnum < q->second) {
+    for (auto map_iter = pool_pg_num_history_map.lower_bound(old_map->get_epoch());
+        map_iter != pool_pg_num_history_map.end();
+        ++map_iter) {
+      const auto& [new_epoch, new_pgnum] = *map_iter;
+      if (new_epoch > new_map->get_epoch()) {
+        // don't handle any changes recorded later than new_map's epoch
+        break;
+      }
+      if (pgnum < new_pgnum) {
        // split?
        if (cur.ps() < pgnum) {
          set<spg_t> children;
-         if (cur.is_split(pgnum, q->second, &children)) {
-           dout(20) << __func__ << " " << cur << " e" << q->first
-                    << " pg_num " << pgnum << " -> " << q->second
+         if (cur.is_split(pgnum, new_pgnum, &children)) {
+           dout(20) << __func__ << " " << cur << " e" << new_epoch
+                    << " pg_num " << pgnum << " -> " << new_pgnum
                     << " children " << children << dendl;
            for (auto i : children) {
-             split_children->insert(make_pair(i, q->first));
+             split_children->insert(make_pair(i, new_epoch));
               if (!did.count(i))
                queue.push_back(i);
            }
          }
-       } else if (cur.ps() < q->second) {
-         dout(20) << __func__ << " " << cur << " e" << q->first
-                  << " pg_num " << pgnum << " -> " << q->second
+       } else if (cur.ps() < new_pgnum) {
+         dout(20) << __func__ << " " << cur << " e" << new_epoch
+                  << " pg_num " << pgnum << " -> " << new_pgnum
                   << " is a child" << dendl;
          // normally we'd capture this from the parent, but it's
          // possible the parent doesn't exist yet (it will be
          // fabricated to allow an intervening merge).  note this PG
          // as a split child here to be sure we catch it.
-         split_children->insert(make_pair(cur, q->first));
+         split_children->insert(make_pair(cur, new_epoch));
        } else {
-         dout(20) << __func__ << " " << cur << " e" << q->first
-                  << " pg_num " << pgnum << " -> " << q->second
+         dout(20) << __func__ << " " << cur << " e" << new_epoch
+                  << " pg_num " << pgnum << " -> " << new_pgnum
                   << " is post-split, skipping" << dendl;
        }
       } else if (merge_pgs) {
        // merge?
-       if (cur.ps() >= q->second) {
+       if (cur.ps() >= new_pgnum) {
          if (cur.ps() < pgnum) {
            spg_t parent;
-           if (cur.is_merge_source(pgnum, q->second, &parent)) {
+           if (cur.is_merge_source(pgnum, new_pgnum, &parent)) {
              set<spg_t> children;
-             parent.is_split(q->second, pgnum, &children);
-             dout(20) << __func__ << " " << cur << " e" << q->first
-                      << " pg_num " << pgnum << " -> " << q->second
+             parent.is_split(new_pgnum, pgnum, &children);
+             dout(20) << __func__ << " " << cur << " e" << new_epoch
+                      << " pg_num " << pgnum << " -> " << new_pgnum
                       << " is merge source, target " << parent
                       << ", source(s) " << children << dendl;
-             merge_pgs->insert(make_pair(parent, q->first));
+             merge_pgs->insert(make_pair(parent, new_epoch));
               if (!did.count(parent)) {
                 // queue (and re-scan) parent in case it might not exist yet
                 // and there are some future splits pending on it
                 queue.push_back(parent);
               }
              for (auto c : children) {
-               merge_pgs->insert(make_pair(c, q->first));
+               merge_pgs->insert(make_pair(c, new_epoch));
                 if (!did.count(c))
                   queue.push_back(c);
              }
            }
          } else {
-           dout(20) << __func__ << " " << cur << " e" << q->first
-                    << " pg_num " << pgnum << " -> " << q->second
+           dout(20) << __func__ << " " << cur << " e" << new_epoch
+                    << " pg_num " << pgnum << " -> " << new_pgnum
                     << " is beyond old pgnum, skipping" << dendl;
          }
        } else {
          set<spg_t> children;
-         if (cur.is_split(q->second, pgnum, &children)) {
-           dout(20) << __func__ << " " << cur << " e" << q->first
-                    << " pg_num " << pgnum << " -> " << q->second
+         if (cur.is_split(new_pgnum, pgnum, &children)) {
+           dout(20) << __func__ << " " << cur << " e" << new_epoch
+                    << " pg_num " << pgnum << " -> " << new_pgnum
                     << " is merge target, source " << children << dendl;
            for (auto c : children) {
-             merge_pgs->insert(make_pair(c, q->first));
+             merge_pgs->insert(make_pair(c, new_epoch));
               if (!did.count(c))
                 queue.push_back(c);
            }
-           merge_pgs->insert(make_pair(cur, q->first));
+           merge_pgs->insert(make_pair(cur, new_epoch));
          }
        }
       }
-      pgnum = q->second;
+      pgnum = new_pgnum;
     }
   }
 }