Fix assertion failure while deleting remote backed index (#14601)

Signed-off-by: Sachin Kale <kalsac@amazon.com>

Author: sachinpkale

server/src/internalClusterTest/java/org/opensearch/remotemigration/RemoteMigrationIndexMetadataUpdateIT.java

@@ -275,7 +275,6 @@ initalMetadataVersion < internalCluster().client()
      * After shard relocation completes, shuts down the docrep nodes and asserts remote
      * index settings are applied even when the index is in YELLOW state
      */
-    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/13737")
     public void testIndexSettingsUpdatedEvenForMisconfiguredReplicas() throws Exception {
         internalCluster().startClusterManagerOnlyNode();
 
@@ -332,7 +331,6 @@ public void testIndexSettingsUpdatedEvenForMisconfiguredReplicas() throws Except
      * After shard relocation completes, restarts the docrep node holding extra replica shard copy
      * and asserts remote index settings are applied as soon as the docrep replica copy is unassigned
      */
-    @AwaitsFix(bugUrl = "https://github.com/opensearch-project/OpenSearch/issues/13871")
     public void testIndexSettingsUpdatedWhenDocrepNodeIsRestarted() throws Exception {
         internalCluster().startClusterManagerOnlyNode();
 

server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreIT.java

@@ -65,7 +65,6 @@
 import static org.opensearch.index.remote.RemoteStoreEnums.DataType.METADATA;
 import static org.opensearch.index.shard.IndexShardTestCase.getTranslog;
 import static org.opensearch.indices.RemoteStoreSettings.CLUSTER_REMOTE_TRANSLOG_BUFFER_INTERVAL_SETTING;
-import static org.opensearch.test.OpenSearchTestCase.getShardLevelBlobPath;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
 import static org.hamcrest.Matchers.comparesEqualTo;
@@ -133,6 +132,21 @@ private void testPeerRecovery(int numberOfIterations, boolean invokeFlush) throw
         );
     }
 
+    public void testRemoteStoreIndexCreationAndDeletionWithReferencedStore() throws InterruptedException, ExecutionException {
+        String dataNode = internalCluster().startNodes(1).get(0);
+        createIndex(INDEX_NAME, remoteStoreIndexSettings(0));
+        ensureYellowAndNoInitializingShards(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+
+        IndexShard indexShard = getIndexShard(dataNode, INDEX_NAME);
+
+        // Simulating a condition where store is already in use by increasing ref count, this helps in testing index
+        // deletion when refresh is in-progress.
+        indexShard.store().incRef();
+        assertAcked(client().admin().indices().prepareDelete(INDEX_NAME));
+        indexShard.store().decRef();
+    }
+
     public void testPeerRecoveryWithRemoteStoreAndRemoteTranslogNoDataFlush() throws Exception {
         testPeerRecovery(1, true);
     }

server/src/main/java/org/opensearch/index/IndexService.java

@@ -602,7 +602,21 @@ public synchronized IndexShard createShard(
                         this.indexSettings.getRemoteStorePathStrategy()
                     );
                 }
-                remoteStore = new Store(shardId, this.indexSettings, remoteDirectory, lock, Store.OnClose.EMPTY, path);
+                // When an instance of Store is created, a shardlock is created which is released on closing the instance of store.
+                // Currently, we create 2 instances of store for remote store backed indices: store and remoteStore.
+                // As there can be only one shardlock acquired for a given shard, the lock is shared between store and remoteStore.
+                // This creates an issue when we are deleting the index as it results in closing both store and remoteStore.
+                // Sample test failure: https://github.com/opensearch-project/OpenSearch/issues/13871
+                // The following method provides ShardLock that is not maintained by NodeEnvironment.
+                // As part of https://github.com/opensearch-project/OpenSearch/issues/13075, we want to move away from keeping 2
+                // store instances.
+                ShardLock remoteStoreLock = new ShardLock(shardId) {
+                    @Override
+                    protected void closeInternal() {
+                        // Do nothing for shard lock on remote store
+                    }
+                };
+                remoteStore = new Store(shardId, this.indexSettings, remoteDirectory, remoteStoreLock, Store.OnClose.EMPTY, path);
             } else {
                 // Disallow shards with remote store based settings to be created on non-remote store enabled nodes
                 // Even though we have `RemoteStoreMigrationAllocationDecider` in place to prevent something like this from happening at the
@@ -625,7 +639,6 @@ public synchronized IndexShard createShard(
             } else {
                 directory = directoryFactory.newDirectory(this.indexSettings, path);
             }
-
             store = new Store(
                 shardId,
                 this.indexSettings,