kv: fix iterator invalidation in memdb

Signed-off-by: Haodong Tang <haodong.tang@intel.com>
ceph · Aug 10, 2016 · db00156 · db00156
1 parent eca56cb
commit db00156
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Showing 2 changed files with 21 additions and 7 deletions.
diff --git a/src/kv/MemDB.cc b/src/kv/MemDB.cc
@@ -125,6 +125,7 @@ void MemDB::_load()
     dout(10) << __func__ << " Key:"<< key << dendl;
     m_btree[key] = datap;
   }
+  m_total_bytes += bytes_done;
   VOID_TEMP_FAILURE_RETRY(::close(fd));
 }
 
@@ -266,7 +267,7 @@ int MemDB::_setkey(ms_op_t &op)
   }
 
   m_btree[key] = bufferptr((char *) bl.c_str(), bl.length());
-
+  iterator_valid = false;
   return 0;
 }
 
@@ -276,10 +277,13 @@ int MemDB::_rmkey(ms_op_t &op)
   std::string key = make_key(op.first.first, op.first.second);
 
   bufferlist bl_old;
+  dtrace << "m_total_bytes is: " << m_total_bytes << dendl;
   if (_get(op.first.first, op.first.second, &bl_old)) {
+    dtrace << "bl_old length is: " << bl_old.length() << dendl;
     assert(m_total_bytes >= bl_old.length());
     m_total_bytes -= bl_old.length();
   }
+  iterator_valid = false;
   /*
    * Erase will call the destructor for bufferptr.
    */
@@ -337,6 +341,7 @@ int MemDB::_merge(ms_op_t &op)
 
   assert((int64_t)m_total_bytes + bytes_adjusted >= 0);
   m_total_bytes += bytes_adjusted;
+  iterator_valid = false;
   return 0;
 }
 
@@ -393,7 +398,7 @@ void MemDB::MDBWholeSpaceIteratorImpl::fill_current()
 
 bool MemDB::MDBWholeSpaceIteratorImpl::valid()
 {
-  if (m_key_value.first.empty()) {
+  if (!(*is_valid) || m_key_value.first.empty()) {
     return false;
   }
   return true;
@@ -442,6 +447,7 @@ bufferlist MemDB::MDBWholeSpaceIteratorImpl::value()
 int MemDB::MDBWholeSpaceIteratorImpl::next()
 {
   std::lock_guard<std::mutex> l(*m_btree_lock_p);
+  if (!(*is_valid)) return -1;
   free_last();
   m_iter++;
   if (m_iter != m_btree_p->end()) {
@@ -455,6 +461,7 @@ int MemDB::MDBWholeSpaceIteratorImpl::next()
 int MemDB::MDBWholeSpaceIteratorImpl:: prev()
 {
   std::lock_guard<std::mutex> l(*m_btree_lock_p);
+  if (!(*is_valid)) return -1;
   free_last();
   m_iter--;
   if (m_iter != m_btree_p->end()) {
@@ -471,23 +478,25 @@ int MemDB::MDBWholeSpaceIteratorImpl:: prev()
 int MemDB::MDBWholeSpaceIteratorImpl::seek_to_first(const std::string &k)
 {
   std::lock_guard<std::mutex> l(*m_btree_lock_p);
+  if (!(*is_valid)) return -1;
   free_last();
   if (k.empty()) {
     m_iter = m_btree_p->begin();
   } else {
     m_iter = m_btree_p->lower_bound(k);
   }
-
+  
   if (m_iter == m_btree_p->end()) {
     return -1;
   }
+  fill_current();
   return 0;
 }
 
 int MemDB::MDBWholeSpaceIteratorImpl::seek_to_last(const std::string &k)
 {
   std::lock_guard<std::mutex> l(*m_btree_lock_p);
-
+  if (!(*is_valid)) return -1;
   free_last();
   if (k.empty()) {
     m_iter = m_btree_p->end();
@@ -499,6 +508,7 @@ int MemDB::MDBWholeSpaceIteratorImpl::seek_to_last(const std::string &k)
   if (m_iter == m_btree_p->end()) {
     return -1;
   }
+  fill_current();
   return 0;
 }
 

diff --git a/src/kv/MemDB.h b/src/kv/MemDB.h
@@ -48,10 +48,11 @@ class MemDB : public KeyValueDB
   void _encode(btree::btree_map<string, bufferptr>:: iterator iter, bufferlist &bl);
   void _save();
   void _load();
+  bool iterator_valid;
 
 public:
   MemDB(CephContext *c, const string &path, void *p) :
-    m_cct(c), m_priv(p), m_db_path(path)
+    m_cct(c), m_priv(p), m_db_path(path), iterator_valid(true)
   {
     //Nothing as of now
   }
@@ -132,12 +133,15 @@ class MemDB : public KeyValueDB
       std::pair<string, bufferlist> m_key_value;
       btree::btree_map<std::string, bufferptr> *m_btree_p;
       std::mutex *m_btree_lock_p;
+      bool *is_valid;
 
   public:
     MDBWholeSpaceIteratorImpl(btree::btree_map<std::string, bufferptr> *btree_p,
-                             std::mutex *btree_lock_p) {
+                             std::mutex *btree_lock_p, bool *is_valid_) {
         m_btree_p = btree_p;
         m_btree_lock_p = btree_lock_p;
+	is_valid = is_valid_;
+	*is_valid = true;
     }
 
     void fill_current();
@@ -183,7 +187,7 @@ class MemDB : public KeyValueDB
 
   WholeSpaceIterator _get_iterator() {
     return std::shared_ptr<KeyValueDB::WholeSpaceIteratorImpl>(
-      new MDBWholeSpaceIteratorImpl(&m_btree, &m_lock));
+      new MDBWholeSpaceIteratorImpl(&m_btree, &m_lock, &iterator_valid));
   }
 
   WholeSpaceIterator _get_snapshot_iterator();