Specify a hint that no special IO behavior should be used (#127606)

Author: thecoop

plugins/store-smb/src/main/java/org/elasticsearch/index/store/smb/SmbMmapFsDirectoryFactory.java

@@ -25,7 +25,7 @@ public final class SmbMmapFsDirectoryFactory extends FsDirectoryFactory {
     @Override
     protected Directory newFSDirectory(Path location, LockFactory lockFactory, IndexSettings indexSettings) throws IOException {
         return new SmbDirectoryWrapper(
-            setPreload(
+            setMMapFunctions(
                 new MMapDirectory(location, lockFactory),
                 new HashSet<>(indexSettings.getValue(IndexModule.INDEX_STORE_PRE_LOAD_SETTING))
             )

server/src/main/java/org/elasticsearch/index/StandardIOBehaviorHint.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.index;
+
+import org.apache.lucene.store.IOContext;
+
+/**
+ * A hint that no special behavior should be set on open files
+ */
+public enum StandardIOBehaviorHint implements IOContext.FileOpenHint {
+    INSTANCE
+}

server/src/main/java/org/elasticsearch/index/store/FsDirectoryFactory.java

@@ -20,12 +20,14 @@
 import org.apache.lucene.store.MMapDirectory;
 import org.apache.lucene.store.NIOFSDirectory;
 import org.apache.lucene.store.NativeFSLockFactory;
+import org.apache.lucene.store.ReadAdvice;
 import org.apache.lucene.store.SimpleFSLockFactory;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.core.IOUtils;
 import org.elasticsearch.index.IndexModule;
 import org.elasticsearch.index.IndexSettings;
+import org.elasticsearch.index.StandardIOBehaviorHint;
 import org.elasticsearch.index.codec.vectors.es818.DirectIOHint;
 import org.elasticsearch.index.shard.ShardPath;
 import org.elasticsearch.logging.LogManager;
@@ -36,6 +38,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.HashSet;
+import java.util.Optional;
 import java.util.OptionalLong;
 import java.util.Set;
 import java.util.function.BiPredicate;
@@ -75,12 +78,12 @@ protected Directory newFSDirectory(Path location, LockFactory lockFactory, Index
                 // Use Lucene defaults
                 final FSDirectory primaryDirectory = FSDirectory.open(location, lockFactory);
                 if (primaryDirectory instanceof MMapDirectory mMapDirectory) {
-                    return new HybridDirectory(lockFactory, setPreload(mMapDirectory, preLoadExtensions));
+                    return new HybridDirectory(lockFactory, setMMapFunctions(mMapDirectory, preLoadExtensions));
                 } else {
                     return primaryDirectory;
                 }
             case MMAPFS:
-                return setPreload(new MMapDirectory(location, lockFactory), preLoadExtensions);
+                return setMMapFunctions(new MMapDirectory(location, lockFactory), preLoadExtensions);
             case SIMPLEFS:
             case NIOFS:
                 return new NIOFSDirectory(location, lockFactory);
@@ -89,10 +92,18 @@ protected Directory newFSDirectory(Path location, LockFactory lockFactory, Index
         }
     }
 
+    private static Optional<ReadAdvice> overrideReadAdvice(String name, IOContext context) {
+        if (context.hints().contains(StandardIOBehaviorHint.INSTANCE)) {
+            return Optional.of(ReadAdvice.NORMAL);
+        }
+        return Optional.empty();
+    }
+
     /** Sets the preload, if any, on the given directory based on the extensions. Returns the same directory instance. */
     // visibility and extensibility for testing
-    public MMapDirectory setPreload(MMapDirectory mMapDirectory, Set<String> preLoadExtensions) {
+    public MMapDirectory setMMapFunctions(MMapDirectory mMapDirectory, Set<String> preLoadExtensions) {
         mMapDirectory.setPreload(getPreloadFunc(preLoadExtensions));
+        mMapDirectory.setReadAdviceOverride(FsDirectoryFactory::overrideReadAdvice);
         return mMapDirectory;
     }
 

server/src/test/java/org/elasticsearch/index/store/FsDirectoryFactoryTests.java

@@ -88,7 +88,7 @@ static class PreLoadExposingFsDirectoryFactory extends FsDirectoryFactory {
         final Map<MMapDirectory, BiPredicate<String, IOContext>> preLoadFuncMap = new HashMap<>();
 
         @Override
-        public MMapDirectory setPreload(MMapDirectory mMapDirectory, Set<String> preLoadExtensions) {
+        public MMapDirectory setMMapFunctions(MMapDirectory mMapDirectory, Set<String> preLoadExtensions) {
             var preLoadFunc = FsDirectoryFactory.getPreloadFunc(preLoadExtensions);
             mMapDirectory.setPreload(preLoadFunc);
             preLoadFuncMap.put(mMapDirectory, preLoadFunc);

x-pack/plugin/searchable-snapshots/src/main/java/org/elasticsearch/xpack/searchablesnapshots/store/input/CachedBlobContainerIndexInput.java

@@ -9,12 +9,10 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-import org.apache.lucene.store.FlushInfo;
 import org.apache.lucene.store.IOContext;
-import org.apache.lucene.store.MergeInfo;
-import org.apache.lucene.store.ReadAdvice;
 import org.elasticsearch.blobcache.BlobCacheUtils;
 import org.elasticsearch.blobcache.common.ByteRange;
+import org.elasticsearch.index.StandardIOBehaviorHint;
 import org.elasticsearch.index.snapshots.blobstore.BlobStoreIndexShardSnapshot.FileInfo;
 import org.elasticsearch.xpack.searchablesnapshots.cache.common.CacheFile;
 import org.elasticsearch.xpack.searchablesnapshots.store.IndexInputStats;
@@ -23,8 +21,6 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.ByteBuffer;
-import java.util.Optional;
-import java.util.Set;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
@@ -40,42 +36,7 @@ public class CachedBlobContainerIndexInput extends MetadataCachingIndexInput {
      * a complete part of the {@link #fileInfo} at once in the cache and should not be
      * used for anything else than what the {@link #prefetchPart(int, Supplier)} method does.
      */
-    public static final IOContext CACHE_WARMING_CONTEXT = new IOContext() {
-        @Override
-        public Context context() {
-            return Context.DEFAULT;
-        }
-
-        @Override
-        public MergeInfo mergeInfo() {
-            return null;
-        }
-
-        @Override
-        public FlushInfo flushInfo() {
-            return null;
-        }
-
-        @Override
-        public Set<FileOpenHint> hints() {
-            return Set.of();
-        }
-
-        @Override
-        public IOContext withHints(FileOpenHint... hints) {
-            return this;
-        }
-
-        @Override
-        public Optional<ReadAdvice> readAdvice() {
-            return Optional.of(ReadAdvice.NORMAL);
-        }
-
-        @Override
-        public IOContext withReadAdvice(ReadAdvice advice) {
-            return this;
-        }
-    };
+    public static final IOContext CACHE_WARMING_CONTEXT = IOContext.DEFAULT.withHints(StandardIOBehaviorHint.INSTANCE);
 
     private static final Logger logger = LogManager.getLogger(CachedBlobContainerIndexInput.class);
 
@@ -141,7 +102,7 @@ private CachedBlobContainerIndexInput(
 
     @Override
     protected void readWithoutBlobCache(ByteBuffer b) throws Exception {
-        ensureContext(ctx -> ctx != CACHE_WARMING_CONTEXT);
+        ensureContext(ctx -> ctx.hints().contains(StandardIOBehaviorHint.INSTANCE) == false);
         final long position = getAbsolutePosition();
         final int length = b.remaining();
 
@@ -178,7 +139,7 @@ public long getPersistentCacheInitialLength() throws Exception {
      * or {@code -1} if the prewarming was cancelled
      */
     public long prefetchPart(final int part, Supplier<Boolean> isCancelled) throws IOException {
-        ensureContext(ctx -> ctx == CACHE_WARMING_CONTEXT);
+        ensureContext(ctx -> ctx.hints().contains(StandardIOBehaviorHint.INSTANCE));
         if (part >= fileInfo.numberOfParts()) {
             throw new IllegalArgumentException("Unexpected part number [" + part + "]");
         }