mds: fix subtree_map simplify, again

Erasing from the vector<> seems to be clobbering the iterator, even when it
preceeds the deletion point.  Use integer index instead. Yuck!

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

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index ab9fa071d4bf341274f7e7111a986b6d57460cf7..902d3d6875b13d0759c3a65d68ff9901079826e0 100644 (file)
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -2240,24 +2240,19 @@ ESubtreeMap *MDCache::create_subtree_map()
   for (map<dirfrag_t, vector<dirfrag_t> >::iterator p = le->subtrees.begin(); p != le->subtrees.end(); ++p) {
     if (le->ambiguous_subtrees.count(p->first))
       continue;
-    vector<dirfrag_t>::iterator q = p->second.begin();
-    while (q != p->second.end()) {
-      if (le->subtrees.count(*q) &&
-         le->ambiguous_subtrees.count(*q) == 0) {
-       vector<dirfrag_t>& b = le->subtrees[*q];
-       dout(10) << "simplify: " << p->first << " swallowing " << *q << " with bounds " << b << dendl;
-       for (vector<dirfrag_t>::iterator r = b.begin(); r != b.end(); ++r)
+    unsigned i = 0;
+    while (i < p->second.size()) {
+      dirfrag_t b = p->second[i];
+      if (le->subtrees.count(b) &&
+         le->ambiguous_subtrees.count(b) == 0) {
+       vector<dirfrag_t>& bb = le->subtrees[b];
+       dout(10) << "simplify: " << p->first << " swallowing " << b << " with bounds " << bb << dendl;
+       for (vector<dirfrag_t>::iterator r = bb.begin(); r != bb.end(); ++r)
          p->second.push_back(*r);
-       le->subtrees.erase(*q);
-       if (q == p->second.begin()) {
-         p->second.erase(q);
-         q = p->second.begin();
-       } else {
-         p->second.erase(q--);
-         ++q;
-       }
+       le->subtrees.erase(b);
+       p->second.erase(p->second.begin() + i);
       } else {
-       ++q;
+       ++i;
       }
     }
   }