diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 3021fb8..46df4cb 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -1426,6 +1426,13 @@
 
 Default is `NEVER`.
 
+[[change.maxSubmittableAtOnce]]change.maxSubmittableAtOnce::
++
+Maximum number of changes that can be chained together in the same repository
+to be submitted at once.
++
+Default is 32767.
+
 [[change.move]]change.move::
 +
 Whether the link:rest-api-changes.html#move-change[Move Change] REST
diff --git a/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java b/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java
index 897d96f..0875317 100644
--- a/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java
+++ b/java/com/google/gerrit/httpd/gitweb/GitwebServlet.java
@@ -43,12 +43,13 @@
 import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
+import com.google.gerrit.server.config.AllProjectsName;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.GitwebCgiConfig;
 import com.google.gerrit.server.config.GitwebConfig;
 import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.git.DelegateRepository;
 import com.google.gerrit.server.git.GitRepositoryManager;
-import com.google.gerrit.server.git.LocalDiskRepositoryManager;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.permissions.ProjectPermission;
@@ -85,6 +86,7 @@
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import org.eclipse.jgit.errors.RepositoryNotFoundException;
+import org.eclipse.jgit.internal.storage.file.FileRepository;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Repository;
 
@@ -101,7 +103,7 @@
   private final Set<String> deniedActions;
   private final Path gitwebCgi;
   private final URI gitwebUrl;
-  private final LocalDiskRepositoryManager repoManager;
+  private final GitRepositoryManager repoManager;
   private final ProjectCache projectCache;
   private final PermissionBackend permissionBackend;
   private final Provider<AnonymousUser> anonymousUserProvider;
@@ -119,12 +121,10 @@
       SshInfo sshInfo,
       Provider<AnonymousUser> anonymousUserProvider,
       GitwebConfig gitwebConfig,
-      GitwebCgiConfig gitwebCgiConfig)
+      GitwebCgiConfig gitwebCgiConfig,
+      AllProjectsName allProjects)
       throws IOException {
-    if (!(repoManager instanceof LocalDiskRepositoryManager)) {
-      throw new ProvisionException("Gitweb can only be used with LocalDiskRepositoryManager");
-    }
-    this.repoManager = (LocalDiskRepositoryManager) repoManager;
+    this.repoManager = repoManager;
     this.projectCache = projectCache;
     this.permissionBackend = permissionBackend;
     this.anonymousUserProvider = anonymousUserProvider;
@@ -132,6 +132,9 @@
     this.gitwebCgi = gitwebCgiConfig.getGitwebCgi();
     this.deniedActions = new HashSet<>();
 
+    // ensure that Gitweb works on supported repository type by checking All-Projects project
+    getProjectRoot(allProjects);
+
     final String url = gitwebConfig.getUrl();
     if ((url != null) && (!url.equals("gitweb"))) {
       URI uri = null;
@@ -537,7 +540,8 @@
     }
   }
 
-  private String[] makeEnv(HttpServletRequest req, ProjectState projectState) {
+  private String[] makeEnv(HttpServletRequest req, ProjectState projectState)
+      throws RepositoryNotFoundException, IOException {
     final EnvList env = new EnvList(_env);
     final int contentLength = Math.max(0, req.getContentLength());
 
@@ -579,7 +583,7 @@
     env.set("GERRIT_CONTEXT_PATH", req.getContextPath() + "/");
     env.set("GERRIT_PROJECT_NAME", nameKey.get());
 
-    env.set("GITWEB_PROJECTROOT", repoManager.getBasePath(nameKey).toAbsolutePath().toString());
+    env.set("GITWEB_PROJECTROOT", getProjectRoot(nameKey));
 
     if (projectState.statePermitsRead()
         && permissionBackend
@@ -636,6 +640,25 @@
     return env.getEnvArray();
   }
 
+  private String getProjectRoot(Project.NameKey nameKey)
+      throws RepositoryNotFoundException, IOException {
+    try (Repository repo = repoManager.openRepository(nameKey)) {
+      return getProjectRoot(repo);
+    }
+  }
+
+  private String getProjectRoot(Repository repo) {
+    if (repo instanceof DelegateRepository) {
+      return getProjectRoot(((DelegateRepository) repo).delegate());
+    }
+
+    if (repo instanceof FileRepository) {
+      return repo.getDirectory().getAbsolutePath();
+    }
+
+    throw new ProvisionException("Gitweb can only be used with FileRepository");
+  }
+
   private void copyContentToCGI(HttpServletRequest req, OutputStream dst) throws IOException {
     final int contentLength = req.getContentLength();
     final InputStream src = req.getInputStream();
diff --git a/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java b/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java
index 0b05607..5d81ae2 100644
--- a/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java
+++ b/java/com/google/gerrit/server/submit/LocalMergeSuperSetComputation.java
@@ -30,6 +30,7 @@
 import com.google.gerrit.extensions.registration.DynamicItem;
 import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.permissions.ChangePermission;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.permissions.PermissionBackendException;
@@ -53,6 +54,7 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevSort;
@@ -64,6 +66,8 @@
 public class LocalMergeSuperSetComputation implements MergeSuperSetComputation {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
+  public static final int MAX_SUBMITTABLE_CHANGES_AT_ONCE_DEFAULT = 1024;
+
   public static class Module extends AbstractModule {
     @Override
     protected void configure() {
@@ -90,19 +94,24 @@
   private final Map<BranchNameKey, Optional<RevCommit>> heads;
   private final ProjectCache projectCache;
   private final ChangeIsVisibleToPredicate.Factory changeIsVisibleToPredicateFactory;
+  private final int maxSubmittableChangesAtOnce;
 
   @Inject
   LocalMergeSuperSetComputation(
       PermissionBackend permissionBackend,
       Provider<InternalChangeQuery> queryProvider,
       ProjectCache projectCache,
-      ChangeIsVisibleToPredicate.Factory changeIsVisibleToPredicateFactory) {
+      ChangeIsVisibleToPredicate.Factory changeIsVisibleToPredicateFactory,
+      @GerritServerConfig Config gerritConfig) {
     this.projectCache = projectCache;
     this.permissionBackend = permissionBackend;
     this.queryProvider = queryProvider;
     this.queryCache = new HashMap<>();
     this.heads = new HashMap<>();
     this.changeIsVisibleToPredicateFactory = changeIsVisibleToPredicateFactory;
+    this.maxSubmittableChangesAtOnce =
+        gerritConfig.getInt(
+            "change", "maxSubmittableAtOnce", MAX_SUBMITTABLE_CHANGES_AT_ONCE_DEFAULT);
   }
 
   @Override
@@ -147,8 +156,10 @@
       }
 
       Set<String> visibleHashes =
-          walkChangesByHashes(visibleCommits, Collections.emptySet(), or, b);
-      Set<String> nonVisibleHashes = walkChangesByHashes(nonVisibleCommits, visibleHashes, or, b);
+          walkChangesByHashes(
+              visibleCommits, Collections.emptySet(), or, b, maxSubmittableChangesAtOnce);
+      Set<String> nonVisibleHashes =
+          walkChangesByHashes(nonVisibleCommits, visibleHashes, or, b, maxSubmittableChangesAtOnce);
 
       ChangeSet partialSet =
           byCommitsOnBranchNotMerged(or, b, visibleHashes, nonVisibleHashes, user);
@@ -248,7 +259,11 @@
   }
 
   private Set<String> walkChangesByHashes(
-      Collection<RevCommit> sourceCommits, Set<String> ignoreHashes, OpenRepo or, BranchNameKey b)
+      Collection<RevCommit> sourceCommits,
+      Set<String> ignoreHashes,
+      OpenRepo or,
+      BranchNameKey b,
+      int limit)
       throws IOException {
     Set<String> destHashes = new HashSet<>();
     or.rw.reset();
@@ -258,7 +273,11 @@
       if (ignoreHashes.contains(name)) {
         continue;
       }
-      destHashes.add(name);
+      if (destHashes.size() < limit) {
+        destHashes.add(name);
+      } else {
+        break;
+      }
       or.rw.markStart(c);
     }
     for (RevCommit c : or.rw) {
@@ -266,7 +285,11 @@
       if (ignoreHashes.contains(name)) {
         continue;
       }
-      destHashes.add(name);
+      if (destHashes.size() < limit) {
+        destHashes.add(name);
+      } else {
+        break;
+      }
     }
 
     return destHashes;
diff --git a/javatests/com/google/gerrit/acceptance/server/change/SubmittedTogetherIT.java b/javatests/com/google/gerrit/acceptance/server/change/SubmittedTogetherIT.java
index a97fb49..a2a6caa 100644
--- a/javatests/com/google/gerrit/acceptance/server/change/SubmittedTogetherIT.java
+++ b/javatests/com/google/gerrit/acceptance/server/change/SubmittedTogetherIT.java
@@ -20,7 +20,9 @@
 
 import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.GitUtil;
+import com.google.gerrit.acceptance.Sandboxed;
 import com.google.gerrit.acceptance.TestProjectInput;
+import com.google.gerrit.acceptance.config.GerritConfig;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
 import com.google.gerrit.entities.Project;
@@ -184,6 +186,26 @@
   }
 
   @Test
+  @Sandboxed
+  @GerritConfig(name = "change.maxSubmittableAtOnce", value = "2")
+  public void submittedTogetherWithMaxChangesLimit() throws Exception {
+    String targetRef = "refs/for/master";
+
+    commitBuilder().add("a.txt", "1").message("subject: 1").create();
+    pushHead(testRepo, targetRef, false);
+
+    RevCommit c2_1 = commitBuilder().add("b.txt", "2").message("subject: 2").create();
+    String id2 = getChangeId(c2_1);
+    pushHead(testRepo, targetRef, false);
+
+    RevCommit c3_1 = commitBuilder().add("b.txt", "3").message("subject: 3").create();
+    String id3 = getChangeId(c3_1);
+    pushHead(testRepo, targetRef, false);
+
+    assertSubmittedTogether(id3, id3, id2);
+  }
+
+  @Test
   public void respectTopicsOnAncestors() throws Exception {
     RevCommit initialHead = projectOperations.project(project).getHead("master");