bk commit into 5.1-falcon tree (jas:1.2605)

[U-ROWVWADEjas]

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ChangeSet@stripped, 2007-04-17 10:45:07-04:00, jas@rowvwade. +1 -0
  Use Transaction::syncIndex to resolve a race condition
  between dropTable and writeComplete.

  storage/falcon/Transaction.cpp@stripped, 2007-04-17 10:45:01-04:00, jas@rowvwade. +8 -6
    Use Transaction::syncIndex to resolve a race condition
    between dropTable and writeComplete.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	jas
# Host:	rowvwade.
# Root:	D:/MySQL/mysql-5.1-falcon

--- 1.76/storage/falcon/Transaction.cpp	2007-04-17 10:45:26 -04:00
+++ 1.77/storage/falcon/Transaction.cpp	2007-04-17 10:45:26 -04:00
@@ -609,10 +609,11 @@
 
 void Transaction::dropTable(Table* table)
 {
+	Sync sync(&syncIndexes, "Transaction::dropTable");
+	sync.lock(Exclusive);
+
 	if (deferredIndexes)
 		{
-		Sync sync(&syncIndexes, "Transaction::dropTable");
-		sync.lock(Exclusive);
 		
 		for (DeferredIndex **ptr = &deferredIndexes, *deferredIndex; (deferredIndex =
*ptr);)
 			if (deferredIndex->index->table == table)
@@ -623,9 +624,9 @@
 				}
 			else
 				ptr = &deferredIndex->next;
-		
-		sync.unlock();
 		}
+	
+	// Keep exclusive lock to avoid race condition with writeComplete
 		
 	for (RecordVersion **ptr = &records, *rec; (rec = *ptr);)
 		if (rec->table == table)
@@ -661,11 +662,12 @@
 		deferredIndexCount--;
 		}
 
-	sync.unlock();
-
+	// Keep the synIndexes lock to avoid a race condition with dropTable
+	
 	if (dependencies == 0)
 		commitRecords();
 
+	sync.unlock();
 	writePending = false;
 }