1 files changed, 29 insertions, 25 deletions

diff --git a/src/emerge.cpp b/src/emerge.cpp
index 3e42742f6..28b286c24 100644
--- a/src/emerge.cpp
+++ b/src/emerge.cpp
@@ -592,18 +592,19 @@ bool EmergeThread::popBlockEmerge(v3s16 *pos, BlockEmergeData *bedata)
 EmergeAction EmergeThread::getBlockOrStartGen(
 	const v3s16 &pos, bool allow_gen, MapBlock **block, BlockMakeData *bmdata)
 {
-	MutexAutoLock envlock(m_server->m_env_mutex);
-
 	// 1). Attempt to fetch block from memory
 	*block = m_map->getBlockNoCreateNoEx(pos);
+
 	if (*block && !(*block)->isDummy()) {
-		if ((*block)->isGenerated())
+		if ((*block)->isGenerated()) {
 			return EMERGE_FROM_MEMORY;
+		}
 	} else {
 		// 2). Attempt to load block from disk if it was not in the memory
 		*block = m_map->loadBlock(pos);
-		if (*block && (*block)->isGenerated())
+		if (*block && (*block)->isGenerated()) {
 			return EMERGE_FROM_DISK;
+		}
 	}
 
 	// 3). Attempt to start generation
@@ -618,7 +619,6 @@ EmergeAction EmergeThread::getBlockOrStartGen(
 MapBlock *EmergeThread::finishGen(v3s16 pos, BlockMakeData *bmdata,
 	std::map<v3s16, MapBlock *> *modified_blocks)
 {
-	MutexAutoLock envlock(m_server->m_env_mutex);
 	ScopeProfiler sp(g_profiler,
 		"EmergeThread: after Mapgen::makeChunk", SPT_AVG);
 
@@ -697,34 +697,38 @@ void *EmergeThread::run()
 			continue;
 		}
 
-		if (blockpos_over_max_limit(pos))
-			continue;
+		{
+			MutexAutoLock envlock(m_server->m_env_mutex);
+			if (blockpos_over_max_limit(pos))
+				continue;
+
+			bool allow_gen = bedata.flags & BLOCK_EMERGE_ALLOW_GEN;
+			EMERGE_DBG_OUT("pos=" PP(pos) " allow_gen=" << allow_gen);
 
-		bool allow_gen = bedata.flags & BLOCK_EMERGE_ALLOW_GEN;
-		EMERGE_DBG_OUT("pos=" PP(pos) " allow_gen=" << allow_gen);
+			action = getBlockOrStartGen(pos, allow_gen, &block, &bmdata);
+			if (action == EMERGE_GENERATED) {
+				{
+					ScopeProfiler sp(g_profiler,
+						"EmergeThread: Mapgen::makeChunk", SPT_AVG);
 
-		action = getBlockOrStartGen(pos, allow_gen, &block, &bmdata);
-		if (action == EMERGE_GENERATED) {
-			{
-				ScopeProfiler sp(g_profiler,
-					"EmergeThread: Mapgen::makeChunk", SPT_AVG);
+					m_mapgen->makeChunk(&bmdata);
+				}
 
-				m_mapgen->makeChunk(&bmdata);
+				block = finishGen(pos, &bmdata, &modified_blocks);
+				if (!block)
+					action = EMERGE_ERRORED;
 			}
 
-			block = finishGen(pos, &bmdata, &modified_blocks);
-			if (!block)
-				action = EMERGE_ERRORED;
-		}
+			runCompletionCallbacks(pos, action, bedata.callbacks);
 
-		runCompletionCallbacks(pos, action, bedata.callbacks);
+			if (block)
+				modified_blocks[pos] = block;
 
-		if (block)
-			modified_blocks[pos] = block;
+			if (!modified_blocks.empty())
+				m_server->SetBlocksNotSent(modified_blocks);
 
-		if (!modified_blocks.empty())
-			m_server->SetBlocksNotSent(modified_blocks);
-		modified_blocks.clear();
+			modified_blocks.clear();
+		}
 	}
 	} catch (VersionMismatchException &e) {
 		std::ostringstream err;