Rename setting to enable mmap

With this commit we rename `node.store.allow_mmapfs` to
`node.store.allow_mmap`. Previously this setting has controlled whether
`mmapfs` could be used as a store type. With the introduction of
`hybridfs` which also relies on memory-mapping,
`node.store.allow_mmapfs` also applies to `hybridfs` and thus we rename
it in order to convey that it is actually used to allow memory-mapping
but not a specific store type.

Relates #36668
Relates #37070

docs/reference/index-modules/store.asciidoc

@@ -76,9 +76,9 @@ memory mapped. All other files are opened using Lucene `NIOFSDirectory`.
 Similarly to `mmapfs` be sure you have allowed plenty of
 <<vm-max-map-count,virtual address space>>.
 
-[[allow-mmapfs]]
+[[allow-mmap]]
 You can restrict the use of the `mmapfs` and the related `hybridfs` store type
-via the setting `node.store.allow_mmapfs`. This is a boolean setting indicating
+via the setting `node.store.allow_mmap`. This is a boolean setting indicating
 whether or not memory-mapping is allowed. The default is to allow it. This
 setting is useful, for example, if you are in an environment where you can not
 control the ability to create a lot of memory maps so you need disable the

docs/reference/migration/migrate_7_0/settings.asciidoc

@@ -36,6 +36,11 @@ of the node id. It can still be configured explicitly in `elasticsearch.yml`.
   available to keep the display output in APIs as `bulk` instead of `write`.
   These fallback settings and this system property have been removed.
 
+[float]
+==== Disabling memory-mapping
+
+* The setting `node.store.allow_mmapfs` has been renamed to `node.store.allow_mmap`.
+
 [float]
 [[remove-http-enabled]]
 ==== Http enabled setting removed

docs/reference/setup/bootstrap-checks.asciidoc

@@ -157,9 +157,9 @@ and is enforced on Linux only. To pass the maximum map count check, you
 must configure `vm.max_map_count` via `sysctl` to be at least `262144`.
 
 Alternatively, the maximum map count check is only needed if you are using
-`mmapfs` as the <<index-modules-store,store type>> for your indices. If you
-<<allow-mmapfs,do not allow>> the use of `mmapfs` then this bootstrap check will
-not be enforced.
+`mmapfs` or `hybridfs` as the <<index-modules-store,store type>> for your
+indices. If you <<allow-mmap,do not allow>> the use of `mmap` then this
+bootstrap check will not be enforced.
 
 === Client JVM check
 

server/src/main/java/org/elasticsearch/bootstrap/BootstrapChecks.java

@@ -407,8 +407,8 @@ final class BootstrapChecks {
 
         @Override
         public BootstrapCheckResult check(final BootstrapContext context) {
-            // we only enforce the check if mmapfs is an allowed store type
-            if (IndexModule.NODE_STORE_ALLOW_MMAPFS.get(context.settings())) {
+            // we only enforce the check if a store is allowed to use mmap at all
+            if (IndexModule.NODE_STORE_ALLOW_MMAP.get(context.settings())) {
                 if (getMaxMapCount() != -1 && getMaxMapCount() < LIMIT) {
                     final String message = String.format(
                             Locale.ROOT,

server/src/main/java/org/elasticsearch/common/settings/ClusterSettings.java

@@ -284,7 +284,7 @@ public final class ClusterSettings extends AbstractScopedSettings {
                     HierarchyCircuitBreakerService.REQUEST_CIRCUIT_BREAKER_OVERHEAD_SETTING,
                     HierarchyCircuitBreakerService.ACCOUNTING_CIRCUIT_BREAKER_LIMIT_SETTING,
                     HierarchyCircuitBreakerService.ACCOUNTING_CIRCUIT_BREAKER_OVERHEAD_SETTING,
-                    IndexModule.NODE_STORE_ALLOW_MMAPFS,
+                    IndexModule.NODE_STORE_ALLOW_MMAP,
                     ClusterService.CLUSTER_SERVICE_SLOW_TASK_LOGGING_THRESHOLD_SETTING,
                     ClusterService.USER_DEFINED_META_DATA,
                     SearchService.DEFAULT_SEARCH_TIMEOUT_SETTING,

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

@@ -84,7 +84,7 @@ import java.util.function.Function;
  */
 public final class IndexModule {
 
-    public static final Setting<Boolean> NODE_STORE_ALLOW_MMAPFS = Setting.boolSetting("node.store.allow_mmapfs", true, Property.NodeScope);
+    public static final Setting<Boolean> NODE_STORE_ALLOW_MMAP = Setting.boolSetting("node.store.allow_mmap", true, Property.NodeScope);
 
     public static final Setting<String> INDEX_STORE_TYPE_SETTING =
             new Setting<>("index.store.type", "", Function.identity(), Property.IndexScope, Property.NodeScope);
@@ -355,8 +355,8 @@ public final class IndexModule {
         IndexSearcherWrapper newWrapper(IndexService indexService);
     }
 
-    public static Type defaultStoreType(final boolean allowMmapfs) {
-        if (allowMmapfs && Constants.JRE_IS_64BIT && MMapDirectory.UNMAP_SUPPORTED) {
+    public static Type defaultStoreType(final boolean allowMmap) {
+        if (allowMmap && Constants.JRE_IS_64BIT && MMapDirectory.UNMAP_SUPPORTED) {
             return Type.HYBRIDFS;
         } else if (Constants.WINDOWS) {
             return Type.SIMPLEFS;
@@ -406,9 +406,9 @@ public final class IndexModule {
             final IndexSettings indexSettings, final Map<String, Function<IndexSettings, IndexStore>> indexStoreFactories) {
         final String storeType = indexSettings.getValue(INDEX_STORE_TYPE_SETTING);
         final Type type;
-        final Boolean allowMmapfs = NODE_STORE_ALLOW_MMAPFS.get(indexSettings.getNodeSettings());
+        final Boolean allowMmap = NODE_STORE_ALLOW_MMAP.get(indexSettings.getNodeSettings());
         if (storeType.isEmpty() || Type.FS.getSettingsKey().equals(storeType)) {
-            type = defaultStoreType(allowMmapfs);
+            type = defaultStoreType(allowMmap);
         } else {
             if (isBuiltinType(storeType)) {
                 type = Type.fromSettingsKey(storeType);
@@ -416,8 +416,8 @@ public final class IndexModule {
                 type = null;
             }
         }
-        if (type != null && type == Type.MMAPFS && allowMmapfs == false) {
-            throw new IllegalArgumentException("store type [mmapfs] is not allowed");
+        if (allowMmap == false && (type == Type.MMAPFS || type == Type.HYBRIDFS)) {
+            throw new IllegalArgumentException("store type [" + storeType + "] is not allowed because mmap is disabled");
         }
         final IndexStore store;
         if (storeType.isEmpty() || isBuiltinType(storeType)) {

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

@@ -88,7 +88,7 @@ public class FsDirectoryService extends DirectoryService {
                 indexSettings.getSettings().get(IndexModule.INDEX_STORE_TYPE_SETTING.getKey(), IndexModule.Type.FS.getSettingsKey());
         IndexModule.Type type;
         if (IndexModule.Type.FS.match(storeType)) {
-            type = IndexModule.defaultStoreType(IndexModule.NODE_STORE_ALLOW_MMAPFS.get(indexSettings.getNodeSettings()));
+            type = IndexModule.defaultStoreType(IndexModule.NODE_STORE_ALLOW_MMAP.get(indexSettings.getNodeSettings()));
         } else {
             type = IndexModule.Type.fromSettingsKey(storeType);
         }

server/src/test/java/org/elasticsearch/bootstrap/MaxMapCountCheckTests.java

@@ -76,12 +76,12 @@ public class MaxMapCountCheckTests extends AbstractBootstrapCheckTestCase {
         /*
          * There are two ways that memory maps are allowed:
          *  - by default
-         *  - mmapfs is explicitly allowed
-         * We want to test that if mmapfs is allowed then the max map count check is enforced.
+         *  - mmap is explicitly allowed
+         * We want to test that if mmap is allowed then the max map count check is enforced.
          */
         final List<Settings> settingsThatAllowMemoryMap = new ArrayList<>();
         settingsThatAllowMemoryMap.add(Settings.EMPTY);
-        settingsThatAllowMemoryMap.add(Settings.builder().put("node.store.allow_mmapfs", true).build());
+        settingsThatAllowMemoryMap.add(Settings.builder().put("node.store.allow_mmap", true).build());
 
         for (final Settings settingThatAllowsMemoryMap : settingsThatAllowMemoryMap) {
             assertFailure(check.check(createTestContext(settingThatAllowsMemoryMap, MetaData.EMPTY_META_DATA)));
@@ -89,8 +89,8 @@ public class MaxMapCountCheckTests extends AbstractBootstrapCheckTestCase {
     }
 
     public void testMaxMapCountCheckNotEnforcedIfMemoryMapNotAllowed() {
-        // nothing should happen if current vm.max_map_count is under the limit but mmapfs is not allowed
-        final Settings settings = Settings.builder().put("node.store.allow_mmapfs", false).build();
+        // nothing should happen if current vm.max_map_count is under the limit but mmap is not allowed
+        final Settings settings = Settings.builder().put("node.store.allow_mmap", false).build();
         final BootstrapContext context = createTestContext(settings, MetaData.EMPTY_META_DATA);
         final BootstrapCheck.BootstrapCheckResult result = check.check(context);
         assertTrue(result.isSuccess());

server/src/test/java/org/elasticsearch/index/IndexModuleTests.java

@@ -383,19 +383,20 @@ public class IndexModuleTests extends ESTestCase {
         indexService.close("simon says", false);
     }
 
-    public void testMmapfsStoreTypeNotAllowed() {
+    public void testMmapNotAllowed() {
+        String storeType = randomFrom(IndexModule.Type.HYBRIDFS.getSettingsKey(), IndexModule.Type.MMAPFS.getSettingsKey());
         final Settings settings = Settings.builder()
                 .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir())
-                .put("index.store.type", "mmapfs")
+                .put("index.store.type", storeType)
                 .build();
         final Settings nodeSettings = Settings.builder()
-                .put(IndexModule.NODE_STORE_ALLOW_MMAPFS.getKey(), false)
+                .put(IndexModule.NODE_STORE_ALLOW_MMAP.getKey(), false)
                 .build();
         final IndexSettings indexSettings = IndexSettingsModule.newIndexSettings(new Index("foo", "_na_"), settings, nodeSettings);
         final IndexModule module =
                 new IndexModule(indexSettings, emptyAnalysisRegistry, new InternalEngineFactory(), Collections.emptyMap());
         final IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () -> newIndexService(module));
-        assertThat(e, hasToString(containsString("store type [mmapfs] is not allowed")));
+        assertThat(e, hasToString(containsString("store type [" + storeType + "] is not allowed")));
     }
 
     class CustomQueryCache implements QueryCache {