Revert "Reduce synchronization on field data cache"

This reverts commit cd9f26c.

Relates #27365

Author: jasontedor

core/src/main/java/org/elasticsearch/index/fielddata/IndexFieldDataService.java

@@ -114,24 +114,19 @@ public <IFD extends IndexFieldData<?>> IFD getForField(MappedFieldType fieldType
         final String fieldName = fieldType.name();
         IndexFieldData.Builder builder = fieldType.fielddataBuilder(fullyQualifiedIndexName);
 
-        IndexFieldDataCache cache = fieldDataCaches.get(fieldName);
-        if (cache == null) {
-            //for perf reason, only synchronize when cache is null
-            synchronized (this) {
-                cache = fieldDataCaches.get(fieldName);
-                //double checked locking to make sure it is thread safe
-                //especially when other threads calling clear() or clearField()
-                if (cache == null) {
-                    String cacheType = indexSettings.getValue(INDEX_FIELDDATA_CACHE_KEY);
-                    if (FIELDDATA_CACHE_VALUE_NODE.equals(cacheType)) {
-                        cache = indicesFieldDataCache.buildIndexFieldDataCache(listener, index(), fieldName);
-                    } else if ("none".equals(cacheType)){
-                        cache = new IndexFieldDataCache.None();
-                    } else {
-                        throw new IllegalArgumentException("cache type not supported [" + cacheType + "] for field [" + fieldName + "]");
-                    }
-                    fieldDataCaches.put(fieldName, cache);
+        IndexFieldDataCache cache;
+        synchronized (this) {
+            cache = fieldDataCaches.get(fieldName);
+            if (cache == null) {
+                String cacheType = indexSettings.getValue(INDEX_FIELDDATA_CACHE_KEY);
+                if (FIELDDATA_CACHE_VALUE_NODE.equals(cacheType)) {
+                    cache = indicesFieldDataCache.buildIndexFieldDataCache(listener, index(), fieldName);
+                } else if ("none".equals(cacheType)){
+                    cache = new IndexFieldDataCache.None();
+                } else {
+                    throw new IllegalArgumentException("cache type not supported [" + cacheType + "] for field [" + fieldName + "]");
                 }
+                fieldDataCaches.put(fieldName, cache);
             }
         }