diff --git a/BUILD b/BUILD
index aac05ab..2f873b7 100644
--- a/BUILD
+++ b/BUILD
@@ -40,5 +40,6 @@
     exports = PLUGIN_DEPS + PLUGIN_TEST_DEPS + [
         ":lfs__plugin",
         "@jgit-lfs//jar",
+        "@joda-time//jar",
     ],
 )
diff --git a/WORKSPACE b/WORKSPACE
index 59a8fb2..bbb161e 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -3,7 +3,7 @@
 load("//:bazlets.bzl", "load_bazlets")
 
 load_bazlets(
-    commit = "1650318289e9981c01e9122c62679b814c7d7a48",
+    commit = "c827ba79413585ab9dfc1bbd0d7f609eedd6aa80",
     #local_path = "/home/<user>/projects/bazlets",
 )
 
diff --git a/external_plugin_deps.bzl b/external_plugin_deps.bzl
index aff59ef..9ca97fa 100644
--- a/external_plugin_deps.bzl
+++ b/external_plugin_deps.bzl
@@ -1,13 +1,13 @@
 load("//tools/bzl:maven_jar.bzl", "GERRIT", "MAVEN_CENTRAL", "MAVEN_LOCAL", "maven_jar")
 
-JGIT_VERSION = "4.9.8.201812241815-r"
+JGIT_VERSION = "5.1.6.201903130242-r"
 REPO = MAVEN_CENTRAL
 
 def external_plugin_deps():
     maven_jar(
         name = "jgit-http-apache",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.http.apache:" + JGIT_VERSION,
-        sha1 = "a33c9029a6ed9b0b476d0763da38d9b4ba3a0a7a",
+        sha1 = "d78a2afacc1c8724be678a095fa02bf9725853a1",
         repository = REPO,
         unsign = True,
         exclude = [
@@ -19,7 +19,7 @@
     maven_jar(
         name = "jgit-lfs",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.lfs:" + JGIT_VERSION,
-        sha1 = "081d5d72d927fa5897ae0bbba72fa7522d502130",
+        sha1 = "a6215064dea54368f2f8c38145006e64c13deb6d",
         repository = REPO,
         unsign = True,
         exclude = [
@@ -31,7 +31,7 @@
     maven_jar(
         name = "jgit-lfs-server",
         artifact = "org.eclipse.jgit:org.eclipse.jgit.lfs.server:" + JGIT_VERSION,
-        sha1 = "d12cdeb61eff7f7ce43de403fadc8a378f7d4726",
+        sha1 = "f5d7ca1220bb6aca07c5d33897a52cb6a0d89cd7",
         repository = REPO,
         unsign = True,
         exclude = [
@@ -39,3 +39,9 @@
             "plugin.properties",
         ],
     )
+
+    maven_jar(
+        name = "joda-time",
+        artifact = "joda-time:joda-time:2.9.9",
+        sha1 = "f7b520c458572890807d143670c9b24f4de90897",
+    )
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/GetLfsGlobalConfig.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/GetLfsGlobalConfig.java
index 40e00b0..ebbc81c 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/GetLfsGlobalConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/GetLfsGlobalConfig.java
@@ -14,19 +14,11 @@
 
 package com.googlesource.gerrit.plugins.lfs;
 
-import static com.google.gerrit.server.permissions.GlobalPermission.ADMINISTRATE_SERVER;
-
 import com.google.common.collect.Maps;
-import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestReadView;
-import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.IdentifiedUser;
-import com.google.gerrit.server.config.AllProjectsName;
-import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.project.ProjectResource;
 import com.google.inject.Inject;
-import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.util.HashMap;
 import java.util.List;
@@ -34,29 +26,17 @@
 @Singleton
 class GetLfsGlobalConfig implements RestReadView<ProjectResource> {
   private final LfsConfigurationFactory lfsConfigFactory;
-  private final AllProjectsName allProjectsName;
-  private final Provider<CurrentUser> self;
-  private final PermissionBackend permissionBackend;
+  private final LfsAdminView adminView;
 
   @Inject
-  GetLfsGlobalConfig(
-      LfsConfigurationFactory lfsConfigFactory,
-      AllProjectsName allProjectsName,
-      Provider<CurrentUser> self,
-      PermissionBackend permissionBackend) {
+  GetLfsGlobalConfig(LfsConfigurationFactory lfsConfigFactory, LfsAdminView adminView) {
     this.lfsConfigFactory = lfsConfigFactory;
-    this.allProjectsName = allProjectsName;
-    this.self = self;
-    this.permissionBackend = permissionBackend;
+    this.adminView = adminView;
   }
 
   @Override
   public LfsGlobalConfigInfo apply(ProjectResource resource) throws RestApiException {
-    IdentifiedUser user = self.get().asIdentifiedUser();
-    if (!(resource.getNameKey().equals(allProjectsName)
-        && permissionBackend.user(user).testOrFalse(ADMINISTRATE_SERVER))) {
-      throw new ResourceNotFoundException();
-    }
+    adminView.validate(resource);
 
     LfsGlobalConfigInfo info = new LfsGlobalConfigInfo();
     LfsGlobalConfig globalConfig = lfsConfigFactory.getGlobalConfig();
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAdminView.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAdminView.java
new file mode 100644
index 0000000..d9d2ad7
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAdminView.java
@@ -0,0 +1,57 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.lfs;
+
+import static com.google.gerrit.server.permissions.GlobalPermission.ADMINISTRATE_SERVER;
+
+import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.config.AllProjectsName;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.project.ProjectResource;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+
+@Singleton
+public class LfsAdminView {
+  private final AllProjectsName allProjectsName;
+  private final PermissionBackend permissionBackend;
+  private final Provider<CurrentUser> self;
+
+  @Inject
+  LfsAdminView(
+      AllProjectsName allProjectsName,
+      PermissionBackend permissionBackend,
+      Provider<CurrentUser> self) {
+    this.allProjectsName = allProjectsName;
+    this.permissionBackend = permissionBackend;
+    this.self = self;
+  }
+
+  /**
+   * Validate REST call.
+   *
+   * @param resource the resource
+   * @throws ResourceNotFoundException if the calling user is not admin, or the resource is not
+   *     {@code All-Projects}.
+   */
+  public void validate(ProjectResource resource) throws ResourceNotFoundException {
+    if (!(resource.getNameKey().equals(allProjectsName)
+        && permissionBackend.user(self.get()).testOrFalse(ADMINISTRATE_SERVER))) {
+      throw new ResourceNotFoundException();
+    }
+  }
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsApiServlet.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsApiServlet.java
index d5eeddc..8982dbe 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsApiServlet.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsApiServlet.java
@@ -19,18 +19,18 @@
 import static com.google.gerrit.extensions.client.ProjectState.HIDDEN;
 import static com.google.gerrit.extensions.client.ProjectState.READ_ONLY;
 import static com.google.gerrit.server.permissions.ProjectPermission.ACCESS;
+import static com.google.gerrit.server.permissions.ProjectPermission.PUSH_AT_LEAST_ONE_REF;
 
-import com.google.common.base.Strings;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.ProjectUtil;
-import com.google.gerrit.common.data.Capable;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.permissions.PermissionBackend;
 import com.google.gerrit.server.project.ProjectCache;
-import com.google.gerrit.server.project.ProjectControl;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsAuthUserProvider;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import org.eclipse.jgit.lfs.errors.LfsException;
@@ -42,15 +42,13 @@
 import org.eclipse.jgit.lfs.server.LargeFileRepository;
 import org.eclipse.jgit.lfs.server.LfsObject;
 import org.eclipse.jgit.lfs.server.LfsProtocolServlet;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Singleton
 public class LfsApiServlet extends LfsProtocolServlet {
   public static final String LFS_OBJECTS_REGEX_REST =
       String.format(LFS_URL_REGEX_TEMPLATE, LFS_OBJECTS_PATH);
 
-  private static final Logger log = LoggerFactory.getLogger(LfsApiServlet.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
   private static final long serialVersionUID = 1L;
   private static final Pattern URL_PATTERN = Pattern.compile(LFS_OBJECTS_REGEX_REST);
 
@@ -125,18 +123,19 @@
 
   private void authorizeUser(CurrentUser user, ProjectState state, LfsRequest request)
       throws LfsUnauthorized {
-    ProjectControl control = state.controlFor(user);
+    Project.NameKey projectName = state.getNameKey();
     if ((request.isDownload()
+            && !permissionBackend.user(user).project(projectName).testOrFalse(ACCESS))
+        || (request.isUpload()
             && !permissionBackend
                 .user(user)
-                .project(state.getProject().getNameKey())
-                .testOrFalse(ACCESS))
-        || (request.isUpload() && Capable.OK != control.canPushToAtLeastOneRef())) {
+                .project(projectName)
+                .testOrFalse(PUSH_AT_LEAST_ONE_REF))) {
       String op = request.getOperation().toLowerCase();
       String project = state.getProject().getName();
-      String userName =
-          Strings.isNullOrEmpty(user.getUserName()) ? "anonymous" : user.getUserName();
-      log.debug("operation {} unauthorized for user {} on project {}", op, userName, project);
+      String userName = user.getUserName().orElse("anonymous");
+      log.atFine().log(
+          "operation %s unauthorized for user %s on project %s", op, userName, project);
       throw new LfsUnauthorized(op, project);
     }
   }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsGson.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsGson.java
new file mode 100644
index 0000000..66398fe
--- /dev/null
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsGson.java
@@ -0,0 +1,49 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.lfs;
+
+import com.google.gson.FieldNamingPolicy;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import com.google.gson.JsonIOException;
+import com.google.gson.JsonSyntaxException;
+import com.google.inject.Singleton;
+import java.io.Reader;
+
+@Singleton
+public class LfsGson {
+  private final Gson gson;
+
+  LfsGson() {
+    this.gson =
+        new GsonBuilder()
+            .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
+            .disableHtmlEscaping()
+            .create();
+  }
+
+  public void toJson(Object src, Appendable writer) throws JsonIOException {
+    gson.toJson(src, writer);
+  }
+
+  public String toJson(Object src) {
+    return gson.toJson(src);
+  }
+
+  public <T> T fromJson(Reader json, Class<T> classOfT)
+      throws JsonSyntaxException, JsonIOException {
+    return gson.fromJson(json, classOfT);
+  }
+}
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsProjectsConfig.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsProjectsConfig.java
index 390a65f..ea5e076 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsProjectsConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsProjectsConfig.java
@@ -21,7 +21,7 @@
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.config.AllProjectsName;
-import com.google.gerrit.server.git.VersionedMetaData;
+import com.google.gerrit.server.git.meta.VersionedMetaData;
 import com.google.gerrit.server.project.ProjectCache;
 import java.io.IOException;
 import java.util.ArrayList;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsRepositoryResolver.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsRepositoryResolver.java
index 3e97db3..59cdb13 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsRepositoryResolver.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsRepositoryResolver.java
@@ -15,16 +15,15 @@
 package com.googlesource.gerrit.plugins.lfs;
 
 import com.google.common.base.Strings;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.inject.Inject;
 import java.util.Map;
 import org.eclipse.jgit.lfs.errors.LfsRepositoryNotFound;
 import org.eclipse.jgit.lfs.server.LargeFileRepository;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class LfsRepositoryResolver {
-  private static final Logger log = LoggerFactory.getLogger(LfsRepositoryResolver.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
 
   private final LfsRepositoriesCache cache;
   private final LfsBackend defaultBackend;
@@ -47,7 +46,8 @@
     } else {
       backend = backends.get(backendName);
       if (backend == null) {
-        log.error("Project {} is configured with not existing backend {}", project, backendName);
+        log.atSevere().log(
+            "Project %s is configured with not existing backend %s", project, backendName);
         throw new LfsRepositoryNotFound(project.get());
       }
     }
@@ -58,11 +58,9 @@
     }
 
     // this is unlikely situation as cache is pre-populated from config but...
-    log.error(
-        "Project {} is configured with not existing backend {} of type {}",
-        project,
-        backend.name(),
-        backend.type);
+    log.atSevere().log(
+        "Project %s is configured with not existing backend %s of type %s",
+        project, backend.name(), backend.type);
     throw new LfsRepositoryNotFound(project.get());
   }
 }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/Lifecycle.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/Lifecycle.java
index ec386f1..90347be 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/Lifecycle.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/Lifecycle.java
@@ -15,18 +15,17 @@
 package com.googlesource.gerrit.plugins.lfs;
 
 import com.google.common.base.Strings;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.events.LifecycleListener;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import org.eclipse.jgit.lib.Config;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Singleton
 public class Lifecycle implements LifecycleListener {
-  private static final Logger log = LoggerFactory.getLogger(Lifecycle.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
 
   private final String name;
   private final Config config;
@@ -48,11 +47,10 @@
   }
 
   private void warn(String msg) {
-    log.warn(
-        "{}; LFS will not be enabled. Run site initialization, or manually set"
-            + " lfs.plugin to '{}' in gerrit.config",
-        msg,
-        name);
+    log.atWarning().log(
+        "%s; LFS will not be enabled. Run site initialization, or manually set"
+            + " lfs.plugin to '%s' in gerrit.config",
+        msg, name);
   }
 
   @Override
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/PutLfsGlobalConfig.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/PutLfsGlobalConfig.java
index b747925..ea4e44e 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/PutLfsGlobalConfig.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/PutLfsGlobalConfig.java
@@ -14,7 +14,6 @@
 
 package com.googlesource.gerrit.plugins.lfs;
 
-import static com.google.gerrit.server.permissions.GlobalPermission.ADMINISTRATE_SERVER;
 import static com.googlesource.gerrit.plugins.lfs.LfsProjectConfigSection.KEY_BACKEND;
 import static com.googlesource.gerrit.plugins.lfs.LfsProjectConfigSection.KEY_ENABLED;
 import static com.googlesource.gerrit.plugins.lfs.LfsProjectConfigSection.KEY_MAX_OBJECT_SIZE;
@@ -27,11 +26,7 @@
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.RestModifyView;
 import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.IdentifiedUser;
-import com.google.gerrit.server.config.AllProjectsName;
-import com.google.gerrit.server.git.MetaDataUpdate;
-import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.git.meta.MetaDataUpdate;
 import com.google.gerrit.server.project.ProjectResource;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -48,9 +43,7 @@
 class PutLfsGlobalConfig implements RestModifyView<ProjectResource, LfsGlobalConfigInput> {
 
   private final String pluginName;
-  private final AllProjectsName allProjectsName;
-  private final PermissionBackend permissionBackend;
-  private final Provider<CurrentUser> self;
+  private final LfsAdminView adminView;
   private final Provider<MetaDataUpdate.User> metaDataUpdateFactory;
   private final LfsConfigurationFactory lfsConfigFactory;
   private final GetLfsGlobalConfig get;
@@ -58,16 +51,12 @@
   @Inject
   PutLfsGlobalConfig(
       @PluginName String pluginName,
-      AllProjectsName allProjectsName,
-      PermissionBackend permissionBackend,
-      Provider<CurrentUser> self,
+      LfsAdminView adminView,
       Provider<MetaDataUpdate.User> metaDataUpdateFactory,
       LfsConfigurationFactory lfsConfigFactory,
       GetLfsGlobalConfig get) {
     this.pluginName = pluginName;
-    this.allProjectsName = allProjectsName;
-    this.permissionBackend = permissionBackend;
-    this.self = self;
+    this.adminView = adminView;
     this.metaDataUpdateFactory = metaDataUpdateFactory;
     this.lfsConfigFactory = lfsConfigFactory;
     this.get = get;
@@ -76,14 +65,9 @@
   @Override
   public LfsGlobalConfigInfo apply(ProjectResource resource, LfsGlobalConfigInput input)
       throws RestApiException {
-    IdentifiedUser user = self.get().asIdentifiedUser();
+    adminView.validate(resource);
     Project.NameKey projectName = resource.getNameKey();
 
-    if (!(projectName.equals(allProjectsName)
-        && permissionBackend.user(user).testOrFalse(ADMINISTRATE_SERVER))) {
-      throw new ResourceNotFoundException();
-    }
-
     if (input == null) {
       input = new LfsGlobalConfigInput();
     }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/SshModule.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/SshModule.java
index e74e813..931ffce 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/SshModule.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/SshModule.java
@@ -17,6 +17,7 @@
 import com.google.gerrit.extensions.registration.DynamicItem;
 import com.google.gerrit.sshd.PluginCommandModule;
 import com.google.gerrit.sshd.plugin.LfsPluginAuthCommand;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsSshAuth;
 
 public class SshModule extends PluginCommandModule {
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/AuthInfo.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/AuthInfo.java
similarity index 93%
rename from src/main/java/com/googlesource/gerrit/plugins/lfs/AuthInfo.java
rename to src/main/java/com/googlesource/gerrit/plugins/lfs/auth/AuthInfo.java
index 4336ed5..9b765d2 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/AuthInfo.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/AuthInfo.java
@@ -12,8 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
+import com.googlesource.gerrit.plugins.lfs.LfsDateTime;
 import java.time.Instant;
 
 public class AuthInfo {
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/ExpiringAction.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/ExpiringAction.java
similarity index 95%
rename from src/main/java/com/googlesource/gerrit/plugins/lfs/ExpiringAction.java
rename to src/main/java/com/googlesource/gerrit/plugins/lfs/auth/ExpiringAction.java
index d3255a1..133a386 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/ExpiringAction.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/ExpiringAction.java
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
 import static org.eclipse.jgit.util.HttpSupport.HDR_AUTHORIZATION;
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAuthToken.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthToken.java
similarity index 97%
rename from src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAuthToken.java
rename to src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthToken.java
index 909d295..7abce2c 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAuthToken.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthToken.java
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
 import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
@@ -23,7 +23,6 @@
 public abstract class LfsAuthToken {
   public abstract static class Processor<T extends LfsAuthToken> {
     private static final char DELIMETER = '~';
-
     protected final LfsCipher cipher;
 
     protected Processor(LfsCipher cipher) {
@@ -39,7 +38,6 @@
       if (!decrypted.isPresent()) {
         return Optional.empty();
       }
-
       return createToken(Splitter.on(DELIMETER).splitToList(decrypted.get()));
     }
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAuthUserProvider.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthUserProvider.java
similarity index 87%
rename from src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAuthUserProvider.java
rename to src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthUserProvider.java
index f7d3078..fcd4736 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsAuthUserProvider.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthUserProvider.java
@@ -12,9 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
-import static com.googlesource.gerrit.plugins.lfs.LfsSshRequestAuthorizer.SSH_AUTH_PREFIX;
+import static com.googlesource.gerrit.plugins.lfs.auth.LfsSshRequestAuthorizer.SSH_AUTH_PREFIX;
 
 import com.google.common.base.Strings;
 import com.google.gerrit.server.AnonymousUser;
@@ -55,9 +55,9 @@
           sshAuth.getUserFromValidToken(
               auth.substring(SSH_AUTH_PREFIX.length()), project, operation);
       if (user.isPresent()) {
-        AccountState acc = accounts.getByUsername(user.get());
-        if (acc != null) {
-          return userFactory.create(acc);
+        Optional<AccountState> acc = accounts.getByUsername(user.get());
+        if (acc.isPresent()) {
+          return userFactory.create(acc.get());
         }
       }
     }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsCipher.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipher.java
similarity index 88%
rename from src/main/java/com/googlesource/gerrit/plugins/lfs/LfsCipher.java
rename to src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipher.java
index aec332a..710b3c1 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsCipher.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipher.java
@@ -12,11 +12,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.common.base.Strings;
+import com.google.common.flogger.FluentLogger;
 import com.google.common.primitives.Bytes;
 import com.google.inject.Singleton;
 import java.security.AlgorithmParameters;
@@ -30,12 +31,10 @@
 import javax.crypto.SecretKey;
 import javax.crypto.spec.IvParameterSpec;
 import org.eclipse.jgit.util.Base64;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Singleton
 public class LfsCipher {
-  private static final Logger log = LoggerFactory.getLogger(LfsCipher.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
   private static final int IV_LENGTH = 16;
   private static final String ALGORITHM = "AES";
   private static final String CIPHER_TYPE = ALGORITHM + "/CBC/PKCS5PADDING";
@@ -56,7 +55,7 @@
       Cipher cipher = cipher(initVector, Cipher.ENCRYPT_MODE);
       return Base64.encodeBytes(Bytes.concat(initVector, cipher.doFinal(input.getBytes(UTF_8))));
     } catch (GeneralSecurityException e) {
-      log.error("Token generation failed with error", e);
+      log.atSevere().withCause(e).log("Token generation failed with error");
       throw new RuntimeException(e);
     }
   }
@@ -73,7 +72,7 @@
       return Optional.of(
           new String(cipher.doFinal(Arrays.copyOfRange(bytes, IV_LENGTH, bytes.length)), UTF_8));
     } catch (GeneralSecurityException e) {
-      log.error("Exception was thrown during token verification", e);
+      log.atSevere().withCause(e).log("Exception was thrown during token verification");
     }
 
     return Optional.empty();
@@ -94,7 +93,7 @@
       generator.init(KEY_SIZE, random);
       return generator.generateKey();
     } catch (NoSuchAlgorithmException e) {
-      log.error("Generating key failed with error", e);
+      log.atSevere().withCause(e).log("Generating key failed with error");
       throw new RuntimeException(e);
     }
   }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsSshAuth.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsSshAuth.java
similarity index 84%
rename from src/main/java/com/googlesource/gerrit/plugins/lfs/LfsSshAuth.java
rename to src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsSshAuth.java
index 08d7ca7..9fd57b9 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsSshAuth.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsSshAuth.java
@@ -12,19 +12,17 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.config.CanonicalWebUrl;
 import com.google.gerrit.sshd.BaseCommand.Failure;
 import com.google.gerrit.sshd.BaseCommand.UnloggedFailure;
 import com.google.gerrit.sshd.plugin.LfsPluginAuthCommand;
-import com.google.gson.FieldNamingPolicy;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
+import com.googlesource.gerrit.plugins.lfs.LfsGson;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.List;
@@ -33,17 +31,16 @@
 public class LfsSshAuth implements LfsPluginAuthCommand.LfsSshPluginAuth {
   private final LfsSshRequestAuthorizer auth;
   private final String canonicalWebUrl;
-  private final Gson gson;
+  private final LfsGson gson;
 
   @Inject
-  LfsSshAuth(LfsSshRequestAuthorizer auth, @CanonicalWebUrl Provider<String> canonicalWebUrl) {
+  LfsSshAuth(
+      LfsSshRequestAuthorizer auth,
+      @CanonicalWebUrl Provider<String> canonicalWebUrl,
+      LfsGson gson) {
     this.auth = auth;
     this.canonicalWebUrl = canonicalWebUrl.get();
-    this.gson =
-        new GsonBuilder()
-            .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
-            .disableHtmlEscaping()
-            .create();
+    this.gson = gson;
   }
 
   @Override
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsSshRequestAuthorizer.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsSshRequestAuthorizer.java
similarity index 86%
rename from src/main/java/com/googlesource/gerrit/plugins/lfs/LfsSshRequestAuthorizer.java
rename to src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsSshRequestAuthorizer.java
index 12c5552..14803ed 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/LfsSshRequestAuthorizer.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/auth/LfsSshRequestAuthorizer.java
@@ -12,17 +12,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.server.CurrentUser;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
+import com.googlesource.gerrit.plugins.lfs.LfsConfigurationFactory;
+import com.googlesource.gerrit.plugins.lfs.LfsDateTime;
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Singleton
 class LfsSshRequestAuthorizer {
@@ -32,10 +33,9 @@
     }
   }
 
-  private static final Logger log = LoggerFactory.getLogger(LfsSshRequestAuthorizer.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
   private static final int DEFAULT_SSH_TIMEOUT = 10;
   static final String SSH_AUTH_PREFIX = "Ssh: ";
-
   private final Processor processor;
   private final Long expiresIn;
 
@@ -49,17 +49,16 @@
               .getGlobalConfig()
               .getInt("auth", null, "sshExpirationSeconds", DEFAULT_SSH_TIMEOUT);
     } catch (IllegalArgumentException e) {
-      log.warn(
-          "Reading expiration timeout failed with error." + " Falling back to default {}",
-          DEFAULT_SSH_TIMEOUT,
-          e);
+      log.atWarning().withCause(e).log(
+          "Reading expiration timeout failed with error. Falling back to default %d",
+          DEFAULT_SSH_TIMEOUT);
     }
     this.expiresIn = timeout;
   }
 
   SshAuthInfo generateAuthInfo(CurrentUser user, String project, String operation) {
     LfsSshAuthToken token =
-        new LfsSshAuthToken(user.getUserName(), project, operation, Instant.now(), expiresIn);
+        new LfsSshAuthToken(user.getUserName().get(), project, operation, Instant.now(), expiresIn);
     return new SshAuthInfo(processor.serialize(token), token.issued, token.expiresIn);
   }
 
@@ -68,13 +67,11 @@
     if (!token.isPresent()) {
       return Optional.empty();
     }
-
     Verifier verifier = new Verifier(token.get(), project, operation);
     if (!verifier.verify()) {
-      log.error("Invalid data was provided with auth token {}.", authToken);
+      log.atSevere().log("Invalid data was provided with auth token %s.", authToken);
       return Optional.empty();
     }
-
     return Optional.of(token.get().user);
   }
 
@@ -100,7 +97,6 @@
       if (values.size() != 5) {
         return Optional.empty();
       }
-
       return Optional.of(
           new LfsSshAuthToken(
               values.get(0),
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizer.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizer.java
index 7e982b5..279217b 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizer.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizer.java
@@ -16,10 +16,10 @@
 
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
-import com.googlesource.gerrit.plugins.lfs.AuthInfo;
-import com.googlesource.gerrit.plugins.lfs.LfsAuthToken;
-import com.googlesource.gerrit.plugins.lfs.LfsCipher;
 import com.googlesource.gerrit.plugins.lfs.LfsDateTime;
+import com.googlesource.gerrit.plugins.lfs.auth.AuthInfo;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsAuthToken;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsCipher;
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
@@ -47,7 +47,6 @@
     if (!token.isPresent()) {
       return false;
     }
-
     return new Verifier(token.get(), operation, id).verify();
   }
 
@@ -72,7 +71,6 @@
       if (values.size() != 4) {
         return Optional.empty();
       }
-
       return Optional.of(
           new LfsFsAuthToken(
               values.get(0),
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LocalLargeFileRepository.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LocalLargeFileRepository.java
index 0a6ef34..f67e0bb 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LocalLargeFileRepository.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/fs/LocalLargeFileRepository.java
@@ -22,11 +22,11 @@
 import com.google.gerrit.extensions.annotations.PluginData;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
-import com.googlesource.gerrit.plugins.lfs.AuthInfo;
-import com.googlesource.gerrit.plugins.lfs.ExpiringAction;
 import com.googlesource.gerrit.plugins.lfs.LfsBackend;
 import com.googlesource.gerrit.plugins.lfs.LfsConfigurationFactory;
 import com.googlesource.gerrit.plugins.lfs.LfsGlobalConfig;
+import com.googlesource.gerrit.plugins.lfs.auth.AuthInfo;
+import com.googlesource.gerrit.plugins.lfs.auth.ExpiringAction;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsGetLocksAction.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsGetLocksAction.java
index 32616f6..a84d458 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsGetLocksAction.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsGetLocksAction.java
@@ -23,18 +23,17 @@
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackend.ForProject;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.ProjectCache;
-import com.google.gerrit.server.project.ProjectControl;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
-import com.googlesource.gerrit.plugins.lfs.LfsAuthUserProvider;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsAuthUserProvider;
 import java.io.IOException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import org.eclipse.jgit.lfs.errors.LfsException;
-import org.eclipse.jgit.lfs.errors.LfsUnauthorized;
 
 public class LfsGetLocksAction extends LfsLocksAction {
   interface Factory extends LfsLocksAction.Factory<LfsGetLocksAction> {}
@@ -42,8 +41,6 @@
   static final Pattern LFS_LOCKS_URL_PATTERN =
       Pattern.compile(String.format(LFS_URL_REGEX_TEMPLATE, LFS_LOCKS_PATH_REGEX));
 
-  private final PermissionBackend permissionBackend;
-
   @Inject
   LfsGetLocksAction(
       PermissionBackend permissionBackend,
@@ -51,8 +48,7 @@
       LfsAuthUserProvider userProvider,
       LfsLocksHandler handler,
       @Assisted LfsLocksContext context) {
-    super(projectCache, userProvider, handler, context);
-    this.permissionBackend = permissionBackend;
+    super(permissionBackend, projectCache, userProvider, handler, context);
   }
 
   @Override
@@ -66,15 +62,14 @@
   }
 
   @Override
-  protected void authorizeUser(ProjectControl control) throws LfsUnauthorized {
-    try {
-      permissionBackend
-          .user(control.getUser())
-          .project(control.getProject().getNameKey())
-          .check(ACCESS);
-    } catch (AuthException | PermissionBackendException e) {
-      throwUnauthorizedOp("list locks", control);
-    }
+  protected void authorizeUser(ForProject project)
+      throws AuthException, PermissionBackendException {
+    project.check(ACCESS);
+  }
+
+  @Override
+  protected String getAction() {
+    return "list-locks";
   }
 
   @Override
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksAction.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksAction.java
index 4fa8680..4b6afb4 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksAction.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksAction.java
@@ -21,28 +21,29 @@
 import static org.apache.http.HttpStatus.SC_UNAUTHORIZED;
 import static org.eclipse.jgit.util.HttpSupport.HDR_AUTHORIZATION;
 
-import com.google.common.base.Strings;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.common.ProjectUtil;
+import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackend.ForProject;
+import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.ProjectCache;
-import com.google.gerrit.server.project.ProjectControl;
 import com.google.gerrit.server.project.ProjectState;
-import com.googlesource.gerrit.plugins.lfs.LfsAuthUserProvider;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsAuthUserProvider;
 import com.googlesource.gerrit.plugins.lfs.locks.LfsLocksHandler.LfsLockExistsException;
 import java.io.IOException;
 import org.eclipse.jgit.lfs.errors.LfsException;
 import org.eclipse.jgit.lfs.errors.LfsRepositoryNotFound;
 import org.eclipse.jgit.lfs.errors.LfsUnauthorized;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 abstract class LfsLocksAction {
   interface Factory<T extends LfsLocksAction> {
     T create(LfsLocksContext context);
   }
 
-  private static final Logger log = LoggerFactory.getLogger(LfsLocksAction.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
   /** Git LFS client uses 'upload' operation to authorize SSH Lock requests */
   private static final String LFS_LOCKING_OPERATION = "upload";
 
@@ -50,12 +51,15 @@
   protected final LfsAuthUserProvider userProvider;
   protected final LfsLocksHandler handler;
   protected final LfsLocksContext context;
+  protected final PermissionBackend permissionBackend;
 
   protected LfsLocksAction(
+      PermissionBackend permissionBackend,
       ProjectCache projectCache,
       LfsAuthUserProvider userProvider,
       LfsLocksHandler handler,
       LfsLocksContext context) {
+    this.permissionBackend = permissionBackend;
     this.projectCache = projectCache;
     this.userProvider = userProvider;
     this.handler = handler;
@@ -67,8 +71,12 @@
       String name = getProjectName();
       ProjectState project = getProject(name);
       CurrentUser user = getUser(name);
-      ProjectControl control = project.controlFor(user);
-      authorizeUser(control);
+      ProjectState state = projectCache.checkedGet(project.getNameKey());
+      try {
+        authorizeUser(permissionBackend.user(user).project(state.getNameKey()));
+      } catch (AuthException | PermissionBackendException e) {
+        throwUnauthorizedOp(getAction(), project, user);
+      }
       doRun(project, user);
     } catch (LfsUnauthorized e) {
       context.sendError(SC_UNAUTHORIZED, e.getMessage());
@@ -83,7 +91,10 @@
 
   protected abstract String getProjectName() throws LfsException;
 
-  protected abstract void authorizeUser(ProjectControl control) throws LfsUnauthorized;
+  protected abstract String getAction();
+
+  protected abstract void authorizeUser(ForProject project)
+      throws AuthException, PermissionBackendException;
 
   protected abstract void doRun(ProjectState project, CurrentUser user)
       throws LfsException, IOException;
@@ -102,13 +113,11 @@
         context.getHeader(HDR_AUTHORIZATION), project, LFS_LOCKING_OPERATION);
   }
 
-  protected void throwUnauthorizedOp(String op, ProjectControl control) throws LfsUnauthorized {
-    String project = control.getProject().getName();
-    String userName =
-        Strings.isNullOrEmpty(control.getUser().getUserName())
-            ? "anonymous"
-            : control.getUser().getUserName();
-    log.debug("operation {} unauthorized for user {} on project {}", op, userName, project);
+  private void throwUnauthorizedOp(String op, ProjectState state, CurrentUser user)
+      throws LfsUnauthorized {
+    String project = state.getProject().getName();
+    String userName = user.getUserName().orElse("anonymous");
+    log.atFine().log("operation %s unauthorized for user %s on project %s", op, userName, project);
     throw new LfsUnauthorized(op, project);
   }
 }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksContext.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksContext.java
index fa5f360..5e4094c 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksContext.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksContext.java
@@ -20,9 +20,8 @@
 
 import com.google.common.base.Supplier;
 import com.google.common.base.Suppliers;
-import com.google.gson.FieldNamingPolicy;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
+import com.google.common.flogger.FluentLogger;
+import com.googlesource.gerrit.plugins.lfs.LfsGson;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.IOException;
@@ -32,11 +31,9 @@
 import java.io.Writer;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 class LfsLocksContext {
-  private static final Logger log = LoggerFactory.getLogger(LfsLocksContext.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
 
   public final String path;
 
@@ -44,9 +41,9 @@
   private final HttpServletResponse res;
   private final Supplier<Writer> writer;
   private final Supplier<Reader> reader;
-  private final Gson gson;
+  private final LfsGson gson;
 
-  LfsLocksContext(final HttpServletRequest req, final HttpServletResponse res) {
+  LfsLocksContext(LfsGson gson, final HttpServletRequest req, final HttpServletResponse res) {
     this.path = req.getPathInfo().startsWith("/") ? req.getPathInfo() : "/" + req.getPathInfo();
     this.req = req;
     this.res = res;
@@ -74,7 +71,7 @@
                 }
               }
             });
-    this.gson = createGson();
+    this.gson = gson;
     setLfsResponseType();
   }
 
@@ -101,7 +98,7 @@
   }
 
   void sendError(int status, Error error) throws IOException {
-    log.error(error.message);
+    log.atSevere().log(error.message);
     res.setStatus(status);
     gson.toJson(error, getWriter());
     getWriter().flush();
@@ -119,13 +116,6 @@
     res.setContentType(CONTENTTYPE_VND_GIT_LFS_JSON);
   }
 
-  private Gson createGson() {
-    return new GsonBuilder()
-        .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
-        .disableHtmlEscaping()
-        .create();
-  }
-
   /** copied from org.eclipse.jgit.lfs.server.LfsProtocolServlet.Error */
   static class Error {
     String message;
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksHandler.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksHandler.java
index 3692374..1de28f4 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksHandler.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksHandler.java
@@ -17,6 +17,7 @@
 import com.google.common.cache.CacheLoader;
 import com.google.common.cache.LoadingCache;
 import com.google.common.collect.ImmutableList;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.cache.CacheModule;
@@ -30,8 +31,6 @@
 import java.util.Optional;
 import java.util.stream.Collectors;
 import org.eclipse.jgit.lfs.errors.LfsException;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 @Singleton
 class LfsLocksHandler {
@@ -55,7 +54,7 @@
     }
   }
 
-  private static final Logger log = LoggerFactory.getLogger(LfsLocksHandler.class);
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
   private static final String CACHE_NAME = "lfs_project_locks";
 
   static Module module() {
@@ -80,7 +79,7 @@
 
   LfsLockResponse createLock(Project.NameKey project, CurrentUser user, LfsCreateLockInput input)
       throws LfsException {
-    log.debug("Create lock for {} in project {}", input.path, project);
+    log.atFine().log("Create lock for %s in project %s", input.path, project);
     LfsProjectLocks locks = projectLocks.getUnchecked(project);
     LfsLock lock = locks.createLock(user, input);
     return new LfsLockResponse(lock);
@@ -89,11 +88,9 @@
   LfsLockResponse deleteLock(
       Project.NameKey project, CurrentUser user, String lockId, LfsDeleteLockInput input)
       throws LfsException {
-    log.debug(
-        "Delete (-f {}) lock for {} in project {}",
-        Boolean.TRUE.equals(input.force),
-        lockId,
-        project);
+    log.atFine().log(
+        "Delete (-f %s) lock for %s in project %s",
+        Boolean.TRUE.equals(input.force), lockId, project);
     LfsProjectLocks locks = projectLocks.getUnchecked(project);
     Optional<LfsLock> hasLock = locks.getLock(lockId);
     if (!hasLock.isPresent()) {
@@ -102,7 +99,7 @@
     }
 
     LfsLock lock = hasLock.get();
-    if (lock.owner.name.equals(user.getUserName())) {
+    if (lock.owner.name.equals(user.getUserName().get())) {
       locks.deleteLock(lock);
       return new LfsLockResponse(lock);
     } else if (input.force) {
@@ -115,26 +112,26 @@
   }
 
   LfsVerifyLocksResponse verifyLocks(Project.NameKey project, final CurrentUser user) {
-    log.debug("Verify list of locks for {} project and user {}", project, user);
+    log.atFine().log("Verify list of locks for %s project and user %s", project, user);
     LfsProjectLocks locks = projectLocks.getUnchecked(project);
     Map<Boolean, List<LfsLock>> groupByOurs =
         locks.getLocks().stream()
             .collect(
                 Collectors.groupingBy(
                     (in) -> {
-                      return in.owner.name.equals(user.getUserName());
+                      return in.owner.name.equals(user.getUserName().get());
                     }));
     return new LfsVerifyLocksResponse(groupByOurs.get(true), groupByOurs.get(false), null);
   }
 
   LfsGetLocksResponse listLocksByPath(Project.NameKey project, String path) {
-    log.debug("Get lock for {} path in {} project", path, project);
+    log.atFine().log("Get lock for %s path in %s project", path, project);
     String lockId = toLockId.apply(path);
     return listLocksById(project, lockId);
   }
 
   LfsGetLocksResponse listLocksById(Project.NameKey project, String id) {
-    log.debug("Get lock for {} id in {} project", id, project);
+    log.atFine().log("Get lock for %s id in %s project", id, project);
     LfsProjectLocks locks = projectLocks.getUnchecked(project);
     Optional<LfsLock> lock = locks.getLock(id);
     List<LfsLock> locksById =
@@ -143,7 +140,7 @@
   }
 
   LfsGetLocksResponse listLocks(Project.NameKey project) {
-    log.debug("Get locks for {} project", project);
+    log.atFine().log("Get locks for %s project", project);
     return new LfsGetLocksResponse(projectLocks.getUnchecked(project).getLocks(), null);
   }
 
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksServlet.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksServlet.java
index 9cdeb62..1e6146d 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksServlet.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsLocksServlet.java
@@ -20,6 +20,7 @@
 
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
+import com.googlesource.gerrit.plugins.lfs.LfsGson;
 import java.io.IOException;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
@@ -35,24 +36,27 @@
 
   private final LfsGetLocksAction.Factory getters;
   private final LfsPutLocksAction.Factory putters;
+  private final LfsGson gson;
 
   @Inject
-  LfsLocksServlet(LfsGetLocksAction.Factory getters, LfsPutLocksAction.Factory putters) {
+  LfsLocksServlet(
+      LfsGetLocksAction.Factory getters, LfsPutLocksAction.Factory putters, LfsGson gson) {
     this.getters = getters;
     this.putters = putters;
+    this.gson = gson;
   }
 
   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp)
       throws ServletException, IOException {
-    LfsLocksContext context = new LfsLocksContext(req, resp);
+    LfsLocksContext context = new LfsLocksContext(gson, req, resp);
     getters.create(context).run();
   }
 
   @Override
   protected void doPost(HttpServletRequest req, HttpServletResponse resp)
       throws ServletException, IOException {
-    LfsLocksContext context = new LfsLocksContext(req, resp);
+    LfsLocksContext context = new LfsLocksContext(gson, req, resp);
     putters.create(context).run();
   }
 }
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsProjectLocks.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsProjectLocks.java
index a578736..4526fa4 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsProjectLocks.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsProjectLocks.java
@@ -16,14 +16,13 @@
 
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
+import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.server.CurrentUser;
-import com.google.gson.FieldNamingPolicy;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
 import com.googlesource.gerrit.plugins.lfs.LfsDateTime;
+import com.googlesource.gerrit.plugins.lfs.LfsGson;
 import com.googlesource.gerrit.plugins.lfs.locks.LfsLocksHandler.LfsLockExistsException;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
@@ -36,21 +35,14 @@
 import java.util.stream.Stream;
 import org.eclipse.jgit.internal.storage.file.LockFile;
 import org.eclipse.jgit.lfs.errors.LfsException;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 class LfsProjectLocks {
   interface Factory {
     LfsProjectLocks create(Project.NameKey project);
   }
 
-  private static final Logger log = LoggerFactory.getLogger(LfsProjectLocks.class);
-  private static final Gson gson =
-      new GsonBuilder()
-          .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
-          .disableHtmlEscaping()
-          .create();
-
+  private static final FluentLogger log = FluentLogger.forEnclosingClass();
+  private final LfsGson gson;
   private final PathToLockId toLockId;
   private final String project;
   private final Path locksPath;
@@ -58,7 +50,11 @@
 
   @Inject
   LfsProjectLocks(
-      PathToLockId toLockId, LfsLocksPathProvider locksPath, @Assisted Project.NameKey project) {
+      LfsGson gson,
+      PathToLockId toLockId,
+      LfsLocksPathProvider locksPath,
+      @Assisted Project.NameKey project) {
+    this.gson = gson;
     this.toLockId = toLockId;
     this.project = project.get();
     this.locksPath = Paths.get(locksPath.get(), this.project);
@@ -75,7 +71,8 @@
           .forEach(
               path -> {
                 if (!Files.isReadable(path)) {
-                  log.warn("Lock file [{}] in project {} is not readable", path, project);
+                  log.atWarning().log(
+                      "Lock file [%s] in project %s is not readable", path, project);
                   return;
                 }
 
@@ -83,11 +80,11 @@
                   LfsLock lock = gson.fromJson(in, LfsLock.class);
                   locks.put(lock.id, lock);
                 } catch (IOException e) {
-                  log.warn("Reading lock [{}] failed", path, e);
+                  log.atWarning().withCause(e).log("Reading lock [%s] failed", path);
                 }
               });
     } catch (IOException e) {
-      log.warn("Reading locks in project {} failed", project, e);
+      log.atWarning().withCause(e).log("Reading locks in project %s failed", project);
     }
   }
 
@@ -96,18 +93,20 @@
   }
 
   LfsLock createLock(CurrentUser user, LfsCreateLockInput input) throws LfsException {
-    log.debug("Create lock for {} in project {}", input.path, project);
+    log.atFine().log("Create lock for %s in project %s", input.path, project);
     String lockId = toLockId.apply(input.path);
     LfsLock lock = locks.getIfPresent(lockId);
     if (lock != null) {
       throw new LfsLockExistsException(lock);
     }
 
-    lock = new LfsLock(lockId, input.path, LfsDateTime.now(), new LfsLockOwner(user.getUserName()));
+    lock =
+        new LfsLock(
+            lockId, input.path, LfsDateTime.now(), new LfsLockOwner(user.getUserName().get()));
     LockFile fileLock = new LockFile(locksPath.resolve(lockId).toFile());
     try {
       if (!fileLock.lock()) {
-        log.warn("Cannot lock path [{}] in project {}", input.path, project);
+        log.atWarning().log("Cannot lock path [%s] in project %s", input.path, project);
         throw new LfsLockExistsException(lock);
       }
     } catch (IOException e) {
@@ -115,7 +114,7 @@
           String.format(
               "Locking path [%s] in project %s failed with error %s",
               input.path, project, e.getMessage());
-      log.warn(error);
+      log.atWarning().log(error);
       throw new LfsException(error);
     }
 
@@ -127,13 +126,13 @@
             String.format(
                 "Locking path [%s] in project %s failed during write with error %s",
                 input.path, project, e.getMessage());
-        log.warn(error);
+        log.atWarning().log(error);
         throw new LfsException(error);
       }
       if (!fileLock.commit()) {
         String error =
             String.format("Committing lock to path [%s] in project %s failed", input.path, project);
-        log.warn(error);
+        log.atWarning().log(error);
         throw new LfsException(error);
       }
       // put lock object to cache while file lock is being hold so that
@@ -155,7 +154,7 @@
         String error =
             String.format(
                 "Deleting lock on path [%s] in project %s is not possible", lock.path, project);
-        log.warn(error);
+        log.atWarning().log(error);
         throw new LfsException(error);
       }
     } catch (IOException e) {
@@ -163,7 +162,7 @@
           String.format(
               "Getting lock on path [%s] in project %s failed with error %s",
               lock.path, project, e.getMessage());
-      log.warn(error);
+      log.atWarning().log(error);
       throw new LfsException(error);
     }
 
@@ -175,7 +174,7 @@
           String.format(
               "Deleting lock on path [%s] in project %s failed with error %s",
               lock.path, project, e.getMessage());
-      log.warn(error);
+      log.atWarning().log(error);
       throw new LfsException(error);
     } finally {
       fileLock.unlock();
diff --git a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsPutLocksAction.java b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsPutLocksAction.java
index ffbcc8d..9e0e23d 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsPutLocksAction.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/lfs/locks/LfsPutLocksAction.java
@@ -16,22 +16,24 @@
 
 import static com.google.gerrit.extensions.api.lfs.LfsDefinitions.LFS_URL_REGEX_TEMPLATE;
 import static com.google.gerrit.extensions.api.lfs.LfsDefinitions.LFS_VERIFICATION_PATH;
+import static com.google.gerrit.server.permissions.ProjectPermission.PUSH_AT_LEAST_ONE_REF;
 import static com.googlesource.gerrit.plugins.lfs.locks.LfsGetLocksAction.LFS_LOCKS_URL_PATTERN;
 
 import com.google.common.base.Strings;
-import com.google.gerrit.common.data.Capable;
+import com.google.gerrit.extensions.restapi.AuthException;
 import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.permissions.PermissionBackend;
+import com.google.gerrit.server.permissions.PermissionBackend.ForProject;
+import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.project.ProjectCache;
-import com.google.gerrit.server.project.ProjectControl;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
-import com.googlesource.gerrit.plugins.lfs.LfsAuthUserProvider;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsAuthUserProvider;
 import java.io.IOException;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import org.eclipse.jgit.lfs.errors.LfsException;
-import org.eclipse.jgit.lfs.errors.LfsUnauthorized;
 
 public class LfsPutLocksAction extends LfsLocksAction {
   interface Factory extends LfsLocksAction.Factory<LfsPutLocksAction> {}
@@ -43,11 +45,12 @@
 
   @Inject
   LfsPutLocksAction(
+      PermissionBackend permissionBackend,
       ProjectCache projectCache,
       LfsAuthUserProvider userProvider,
       LfsLocksHandler handler,
       @Assisted LfsLocksContext context) {
-    super(projectCache, userProvider, handler, context);
+    super(permissionBackend, projectCache, userProvider, handler, context);
   }
 
   @Override
@@ -74,11 +77,15 @@
   }
 
   @Override
-  protected void authorizeUser(ProjectControl control) throws LfsUnauthorized {
+  protected void authorizeUser(ForProject project)
+      throws AuthException, PermissionBackendException {
     // all operations require push permission
-    if (Capable.OK != control.canPushToAtLeastOneRef()) {
-      throwUnauthorizedOp(action.getName(), control);
-    }
+    project.check(PUSH_AT_LEAST_ONE_REF);
+  }
+
+  @Override
+  protected String getAction() {
+    return action.getName();
   }
 
   @Override
diff --git a/src/test/java/com/googlesource/gerrit/plugins/lfs/LfsIT.java b/src/test/java/com/googlesource/gerrit/plugins/lfs/LfsIT.java
new file mode 100644
index 0000000..265f47d
--- /dev/null
+++ b/src/test/java/com/googlesource/gerrit/plugins/lfs/LfsIT.java
@@ -0,0 +1,50 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.lfs;
+
+import com.google.gerrit.acceptance.GerritConfig;
+import com.google.gerrit.acceptance.LightweightPluginDaemonTest;
+import com.google.gerrit.acceptance.TestPlugin;
+import com.google.gerrit.reviewdb.client.Project;
+import org.junit.Test;
+
+@TestPlugin(
+    name = "lfs",
+    sysModule = "com.googlesource.gerrit.plugins.lfs.Module",
+    httpModule = "com.googlesource.gerrit.plugins.lfs.HttpModule",
+    sshModule = "com.googlesource.gerrit.plugins.lfs.SshModule")
+public class LfsIT extends LightweightPluginDaemonTest {
+  @Test
+  @GerritConfig(name = "lfs.plugin", value = "lfs")
+  public void globalConfigCanBeReadByAdmin() throws Exception {
+    adminRestSession.get(globalConfig(allProjects)).assertOK();
+  }
+
+  @Test
+  @GerritConfig(name = "lfs.plugin", value = "lfs")
+  public void globalConfigCannotBeReadByNonAdmin() throws Exception {
+    userRestSession.get(globalConfig(allProjects)).assertNotFound();
+  }
+
+  @Test
+  @GerritConfig(name = "lfs.plugin", value = "lfs")
+  public void globalConfigCannotBeReadOnOtherProject() throws Exception {
+    adminRestSession.get(globalConfig(project)).assertNotFound();
+  }
+
+  private static String globalConfig(Project.NameKey name) {
+    return String.format("/projects/%s/lfs:config-global", name.get());
+  }
+}
diff --git a/src/test/java/com/googlesource/gerrit/plugins/lfs/LfsAuthTokenTest.java b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthTokenTest.java
similarity index 96%
rename from src/test/java/com/googlesource/gerrit/plugins/lfs/LfsAuthTokenTest.java
rename to src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthTokenTest.java
index f41307b..bdf7c21 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/lfs/LfsAuthTokenTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsAuthTokenTest.java
@@ -12,10 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
 import static com.google.common.truth.Truth.assertThat;
 
+import com.googlesource.gerrit.plugins.lfs.LfsDateTime;
 import java.time.Instant;
 import java.util.ArrayList;
 import java.util.List;
@@ -30,9 +31,7 @@
     TestTokenProessor processor = new TestTokenProessor(cipher);
     TestToken token = new TestToken(Instant.now(), 0L);
     String serialized = processor.serialize(token);
-
     assertThat(serialized).isNotEmpty();
-
     Optional<TestToken> deserialized = processor.deserialize(serialized);
     assertThat(deserialized.isPresent()).isTrue();
     assertThat(token.issued).isEqualTo(deserialized.get().issued);
diff --git a/src/test/java/com/googlesource/gerrit/plugins/lfs/LfsCipherTest.java b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipherTest.java
similarity index 97%
rename from src/test/java/com/googlesource/gerrit/plugins/lfs/LfsCipherTest.java
rename to src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipherTest.java
index b092a48..08d8dc8 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/lfs/LfsCipherTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/lfs/auth/LfsCipherTest.java
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.googlesource.gerrit.plugins.lfs;
+package com.googlesource.gerrit.plugins.lfs.auth;
 
 import static com.google.common.truth.Truth.assertThat;
 
diff --git a/src/test/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizerTest.java b/src/test/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizerTest.java
index 8cd7225..d2b38c2 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizerTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/lfs/fs/LfsFsRequestAuthorizerTest.java
@@ -17,8 +17,8 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.eclipse.jgit.lfs.lib.LongObjectId.zeroId;
 
-import com.googlesource.gerrit.plugins.lfs.AuthInfo;
-import com.googlesource.gerrit.plugins.lfs.LfsCipher;
+import com.googlesource.gerrit.plugins.lfs.auth.AuthInfo;
+import com.googlesource.gerrit.plugins.lfs.auth.LfsCipher;
 import com.googlesource.gerrit.plugins.lfs.fs.LfsFsRequestAuthorizer.Processor;
 import java.time.Instant;
 import org.eclipse.jgit.lfs.lib.LongObjectId;