merge from 5.1

storage/innobase/buf/buf0buf.c

@@ -2448,22 +2448,29 @@ wait_until_unfixed:
 
 		UNIV_MEM_INVALID(bpage, sizeof *bpage);
 
-		mutex_exit(&block->mutex);
-		mutex_exit(&buf_pool->zip_mutex);
 		buf_pool->n_pend_unzip++;
-
 		buf_pool_mutex_exit(buf_pool);
 
+		access_time = buf_page_is_accessed(&block->page);
+		mutex_exit(&block->mutex);
+		mutex_exit(&buf_pool->zip_mutex);
+
 		buf_page_free_descriptor(bpage);
 
-		/* Decompress the page and apply buffered operations
-		while not holding buf_pool->mutex or block->mutex. */
+		/* Decompress the page while not holding
+		buf_pool->mutex or block->mutex. */
 		success = buf_zip_decompress(block, srv_use_checksums);
 		ut_a(success);
 
 		if (UNIV_LIKELY(!recv_no_ibuf_operations)) {
-			ibuf_merge_or_delete_for_page(block, space, offset,
-						      zip_size, TRUE);
+			if (access_time) {
+#ifdef UNIV_IBUF_COUNT_DEBUG
+				ut_a(ibuf_count_get(space, offset) == 0);
+#endif /* UNIV_IBUF_COUNT_DEBUG */
+			} else {
+				ibuf_merge_or_delete_for_page(
+					block, space, offset, zip_size, TRUE);
+			}
 		}
 
 		/* Unfix and unlatch the block. */