diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index 9e67c66..c67e33d 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -75,6 +75,7 @@
         "snapshot.cpp",
         "snapshot_metadata_updater.cpp",
         "partition_cow_creator.cpp",
+        "return.cpp",
         "utility.cpp",
     ],
 }
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/return.h b/fs_mgr/libsnapshot/include/libsnapshot/return.h
new file mode 100644
index 0000000..dedc445
--- /dev/null
+++ b/fs_mgr/libsnapshot/include/libsnapshot/return.h
@@ -0,0 +1,59 @@
+// 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.
+
+#pragma once
+
+#include <stdint.h>
+#include <string.h>
+
+#include <libfiemap/fiemap_status.h>
+
+namespace android::snapshot {
+
+// SnapshotManager functions return either bool or Return objects. "Return" types provides
+// more information about the reason of the failure.
+class Return {
+    using FiemapStatus = android::fiemap::FiemapStatus;
+
+  public:
+    enum class ErrorCode : int32_t {
+        SUCCESS = static_cast<int32_t>(FiemapStatus::ErrorCode::SUCCESS),
+        ERROR = static_cast<int32_t>(FiemapStatus::ErrorCode::ERROR),
+        NO_SPACE = static_cast<int32_t>(FiemapStatus::ErrorCode::NO_SPACE),
+    };
+    ErrorCode error_code() const { return error_code_; }
+    bool is_ok() const { return error_code() == ErrorCode::SUCCESS; }
+    operator bool() const { return is_ok(); }
+    // Total required size on /userdata.
+    uint64_t required_size() const { return required_size_; }
+    std::string string() const;
+
+    static Return Ok() { return Return(ErrorCode::SUCCESS); }
+    static Return Error() { return Return(ErrorCode::ERROR); }
+    static Return NoSpace(uint64_t size) { return Return(ErrorCode::NO_SPACE, size); }
+    // Does not set required_size_ properly even when status.error_code() == NO_SPACE.
+    explicit Return(const FiemapStatus& status)
+        : error_code_(FromFiemapStatusErrorCode(status.error_code())), required_size_(0) {}
+
+  private:
+    ErrorCode error_code_;
+    uint64_t required_size_;
+    Return(ErrorCode error_code, uint64_t required_size = 0)
+        : error_code_(error_code), required_size_(required_size) {}
+
+    // FiemapStatus::ErrorCode -> ErrorCode
+    static ErrorCode FromFiemapStatusErrorCode(FiemapStatus::ErrorCode error_code);
+};
+
+}  // namespace android::snapshot
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index 61946f7..e503ec3 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -35,6 +35,7 @@
 #include <update_engine/update_metadata.pb.h>
 
 #include <libsnapshot/auto_device.h>
+#include <libsnapshot/return.h>
 
 #ifndef FRIEND_TEST
 #define FRIEND_TEST(test_set_name, individual_test) \
@@ -91,27 +92,6 @@
     using FiemapStatus = android::fiemap::FiemapStatus;
 
   public:
-    // SnapshotManager functions return either bool or Return objects. "Return" types provides
-    // more information about the reason of the failure.
-    class Return : public FiemapStatus {
-      public:
-        // Total required size on /userdata.
-        uint64_t required_size() const { return required_size_; }
-
-        static Return Ok() { return Return(FiemapStatus::ErrorCode::SUCCESS); }
-        static Return Error() { return Return(FiemapStatus::ErrorCode::ERROR); }
-        static Return NoSpace(uint64_t size) {
-            return Return(FiemapStatus::ErrorCode::NO_SPACE, size);
-        }
-        // Does not set required_size_ properly even when status.error_code() == NO_SPACE.
-        explicit Return(const FiemapStatus& status) : Return(status.error_code()) {}
-
-      private:
-        uint64_t required_size_;
-        Return(FiemapStatus::ErrorCode code, uint64_t required_size = 0)
-            : FiemapStatus(code), required_size_(required_size) {}
-    };
-
     // Dependency injection for testing.
     class IDeviceInfo {
       public:
diff --git a/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h b/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
index 11de6ed..98bf56a 100644
--- a/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
+++ b/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
@@ -42,7 +42,6 @@
 using testing::_;
 using testing::AssertionResult;
 using testing::NiceMock;
-using testing::Return;
 
 using namespace android::storage_literals;
 using namespace std::string_literals;
@@ -117,6 +116,7 @@
 class SnapshotTestPropertyFetcher : public android::fs_mgr::testing::MockPropertyFetcher {
   public:
     SnapshotTestPropertyFetcher(const std::string& slot_suffix) {
+        using testing::Return;
         ON_CALL(*this, GetProperty("ro.boot.slot_suffix", _)).WillByDefault(Return(slot_suffix));
         ON_CALL(*this, GetBoolProperty("ro.boot.dynamic_partitions", _))
                 .WillByDefault(Return(true));
diff --git a/fs_mgr/libsnapshot/return.cpp b/fs_mgr/libsnapshot/return.cpp
new file mode 100644
index 0000000..cc64af5
--- /dev/null
+++ b/fs_mgr/libsnapshot/return.cpp
@@ -0,0 +1,44 @@
+// 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.
+
+#include <libsnapshot/return.h>
+
+#include <string.h>
+
+using android::fiemap::FiemapStatus;
+
+namespace android::snapshot {
+
+std::string Return::string() const {
+    switch (error_code()) {
+        case ErrorCode::ERROR:
+            return "Error";
+        case ErrorCode::SUCCESS:
+            [[fallthrough]];
+        case ErrorCode::NO_SPACE:
+            return strerror(-static_cast<int>(error_code()));
+    }
+}
+
+Return::ErrorCode Return::FromFiemapStatusErrorCode(FiemapStatus::ErrorCode error_code) {
+    switch (error_code) {
+        case FiemapStatus::ErrorCode::SUCCESS:
+        case FiemapStatus::ErrorCode::ERROR:
+        case FiemapStatus::ErrorCode::NO_SPACE:
+            return static_cast<ErrorCode>(error_code);
+        default:
+            return ErrorCode::ERROR;
+    }
+}
+}  // namespace android::snapshot
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index 70a69a5..81ffcaf 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -290,7 +290,7 @@
     return true;
 }
 
-SnapshotManager::Return SnapshotManager::CreateCowImage(LockedFile* lock, const std::string& name) {
+Return SnapshotManager::CreateCowImage(LockedFile* lock, const std::string& name) {
     CHECK(lock);
     CHECK(lock->lock_mode() == LOCK_EX);
     if (!EnsureImageManager()) return Return::Error();
@@ -1890,21 +1890,19 @@
     }
 }
 
-static SnapshotManager::Return AddRequiredSpace(
-        SnapshotManager::Return orig,
-        const std::map<std::string, SnapshotStatus>& all_snapshot_status) {
-    if (orig.error_code() != SnapshotManager::Return::ErrorCode::NO_SPACE) {
+static Return AddRequiredSpace(Return orig,
+                               const std::map<std::string, SnapshotStatus>& all_snapshot_status) {
+    if (orig.error_code() != Return::ErrorCode::NO_SPACE) {
         return orig;
     }
     uint64_t sum = 0;
     for (auto&& [name, status] : all_snapshot_status) {
         sum += status.cow_file_size();
     }
-    return SnapshotManager::Return::NoSpace(sum);
+    return Return::NoSpace(sum);
 }
 
-SnapshotManager::Return SnapshotManager::CreateUpdateSnapshots(
-        const DeltaArchiveManifest& manifest) {
+Return SnapshotManager::CreateUpdateSnapshots(const DeltaArchiveManifest& manifest) {
     auto lock = LockExclusive();
     if (!lock) return Return::Error();
 
@@ -1998,7 +1996,7 @@
     return Return::Ok();
 }
 
-SnapshotManager::Return SnapshotManager::CreateUpdateSnapshotsInternal(
+Return SnapshotManager::CreateUpdateSnapshotsInternal(
         LockedFile* lock, const DeltaArchiveManifest& manifest, PartitionCowCreator* cow_creator,
         AutoDeviceList* created_devices,
         std::map<std::string, SnapshotStatus>* all_snapshot_status) {
@@ -2131,7 +2129,7 @@
     return Return::Ok();
 }
 
-SnapshotManager::Return SnapshotManager::InitializeUpdateSnapshots(
+Return SnapshotManager::InitializeUpdateSnapshots(
         LockedFile* lock, MetadataBuilder* target_metadata,
         const LpMetadata* exported_target_metadata, const std::string& target_suffix,
         const std::map<std::string, SnapshotStatus>& all_snapshot_status) {
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index cea9d69..47ac474 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -1604,7 +1604,7 @@
     ASSERT_TRUE(sm->BeginUpdate());
     auto res = sm->CreateUpdateSnapshots(manifest_);
     ASSERT_FALSE(res);
-    ASSERT_EQ(SnapshotManager::Return::ErrorCode::NO_SPACE, res.error_code());
+    ASSERT_EQ(Return::ErrorCode::NO_SPACE, res.error_code());
     ASSERT_GE(res.required_size(), 14_MiB);
     ASSERT_LT(res.required_size(), 15_MiB);
 }
diff --git a/fs_mgr/libsnapshot/utility.cpp b/fs_mgr/libsnapshot/utility.cpp
index f01500f..3a64448 100644
--- a/fs_mgr/libsnapshot/utility.cpp
+++ b/fs_mgr/libsnapshot/utility.cpp
@@ -86,9 +86,7 @@
     }
 }
 
-SnapshotManager::Return InitializeCow(const std::string& device) {
-    using Return = SnapshotManager::Return;
-
+Return InitializeCow(const std::string& device) {
     // When the kernel creates a persistent dm-snapshot, it requires a CoW file
     // to store the modifications. The kernel interface does not specify how
     // the CoW is used, and there is no standard associated.
diff --git a/fs_mgr/libsnapshot/utility.h b/fs_mgr/libsnapshot/utility.h
index 0453256..ad46090 100644
--- a/fs_mgr/libsnapshot/utility.h
+++ b/fs_mgr/libsnapshot/utility.h
@@ -111,7 +111,7 @@
         android::fs_mgr::MetadataBuilder* builder, const std::string& suffix);
 
 // Initialize a device before using it as the COW device for a dm-snapshot device.
-SnapshotManager::Return InitializeCow(const std::string& device);
+Return InitializeCow(const std::string& device);
 
 // "Atomically" write string to file. This is done by a series of actions:
 // 1. Write to path + ".tmp"