20 files changed, 362 insertions, 272 deletions

diff --git a/src/android/app/src/main/jni/native.cpp b/src/android/app/src/main/jni/native.cpp
index 136c8dee6..8017eb58d 100644
--- a/src/android/app/src/main/jni/native.cpp
+++ b/src/android/app/src/main/jni/native.cpp
@@ -770,8 +770,8 @@ void Java_org_yuzu_yuzu_1emu_NativeLibrary_initializeEmptyUserDirectory(JNIEnv*
     ASSERT(user_id);
 
     const auto user_save_data_path = FileSys::SaveDataFactory::GetFullPath(
-        EmulationSession::GetInstance().System(), vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser,
-        FileSys::SaveDataType::SaveData, 1, user_id->AsU128(), 0);
+        {}, vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser, FileSys::SaveDataType::SaveData, 1,
+        user_id->AsU128(), 0);
 
     const auto full_path = Common::FS::ConcatPathSafe(nand_dir, user_save_data_path);
     if (!Common::FS::CreateParentDirs(full_path)) {
@@ -878,7 +878,7 @@ jstring Java_org_yuzu_yuzu_1emu_NativeLibrary_getSavePath(JNIEnv* env, jobject j
                                                             FileSys::Mode::Read);
 
     const auto user_save_data_path = FileSys::SaveDataFactory::GetFullPath(
-        system, vfsNandDir, FileSys::SaveDataSpaceId::NandUser, FileSys::SaveDataType::SaveData,
+        {}, vfsNandDir, FileSys::SaveDataSpaceId::NandUser, FileSys::SaveDataType::SaveData,
         program_id, user_id->AsU128(), 0);
     return ToJString(env, user_save_data_path);
 }
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index 753f55ebe..293d9647b 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -490,6 +490,10 @@ add_library(core STATIC
     hle/service/filesystem/fsp_pr.h
     hle/service/filesystem/fsp_srv.cpp
     hle/service/filesystem/fsp_srv.h
+    hle/service/filesystem/romfs_controller.cpp
+    hle/service/filesystem/romfs_controller.h
+    hle/service/filesystem/save_data_controller.cpp
+    hle/service/filesystem/save_data_controller.h
     hle/service/fgm/fgm.cpp
     hle/service/fgm/fgm.h
     hle/service/friend/friend.cpp
diff --git a/src/core/core.cpp b/src/core/core.cpp
index c063f7719..461eea9c8 100644
--- a/src/core/core.cpp
+++ b/src/core/core.cpp
@@ -413,6 +413,7 @@ struct System::Impl {
         kernel.ShutdownCores();
         services.reset();
         service_manager.reset();
+        fs_controller.Reset();
         cheat_engine.reset();
         telemetry_session.reset();
         time_manager.Shutdown();
diff --git a/src/core/file_sys/savedata_factory.cpp b/src/core/file_sys/savedata_factory.cpp
index 12b3bd797..23196cd5f 100644
--- a/src/core/file_sys/savedata_factory.cpp
+++ b/src/core/file_sys/savedata_factory.cpp
@@ -97,8 +97,9 @@ std::string SaveDataAttribute::DebugInfo() const {
                        static_cast<u8>(rank), index);
 }
 
-SaveDataFactory::SaveDataFactory(Core::System& system_, VirtualDir save_directory_)
-    : dir{std::move(save_directory_)}, system{system_} {
+SaveDataFactory::SaveDataFactory(Core::System& system_, ProgramId program_id_,
+                                 VirtualDir save_directory_)
+    : system{system_}, program_id{program_id_}, dir{std::move(save_directory_)} {
     // Delete all temporary storages
     // On hardware, it is expected that temporary storage be empty at first use.
     dir->DeleteSubdirectoryRecursive("temp");
@@ -110,7 +111,7 @@ VirtualDir SaveDataFactory::Create(SaveDataSpaceId space, const SaveDataAttribut
     PrintSaveDataAttributeWarnings(meta);
 
     const auto save_directory =
-        GetFullPath(system, dir, space, meta.type, meta.title_id, meta.user_id, meta.save_id);
+        GetFullPath(program_id, dir, space, meta.type, meta.title_id, meta.user_id, meta.save_id);
 
     return dir->CreateDirectoryRelative(save_directory);
 }
@@ -118,7 +119,7 @@ VirtualDir SaveDataFactory::Create(SaveDataSpaceId space, const SaveDataAttribut
 VirtualDir SaveDataFactory::Open(SaveDataSpaceId space, const SaveDataAttribute& meta) const {
 
     const auto save_directory =
-        GetFullPath(system, dir, space, meta.type, meta.title_id, meta.user_id, meta.save_id);
+        GetFullPath(program_id, dir, space, meta.type, meta.title_id, meta.user_id, meta.save_id);
 
     auto out = dir->GetDirectoryRelative(save_directory);
 
@@ -147,14 +148,14 @@ std::string SaveDataFactory::GetSaveDataSpaceIdPath(SaveDataSpaceId space) {
     }
 }
 
-std::string SaveDataFactory::GetFullPath(Core::System& system, VirtualDir dir,
+std::string SaveDataFactory::GetFullPath(ProgramId program_id, VirtualDir dir,
                                          SaveDataSpaceId space, SaveDataType type, u64 title_id,
                                          u128 user_id, u64 save_id) {
     // According to switchbrew, if a save is of type SaveData and the title id field is 0, it should
     // be interpreted as the title id of the current process.
     if (type == SaveDataType::SaveData || type == SaveDataType::DeviceSaveData) {
         if (title_id == 0) {
-            title_id = system.GetApplicationProcessProgramID();
+            title_id = program_id;
         }
     }
 
@@ -201,7 +202,7 @@ std::string SaveDataFactory::GetUserGameSaveDataRoot(u128 user_id, bool future)
 SaveDataSize SaveDataFactory::ReadSaveDataSize(SaveDataType type, u64 title_id,
                                                u128 user_id) const {
     const auto path =
-        GetFullPath(system, dir, SaveDataSpaceId::NandUser, type, title_id, user_id, 0);
+        GetFullPath(program_id, dir, SaveDataSpaceId::NandUser, type, title_id, user_id, 0);
     const auto relative_dir = GetOrCreateDirectoryRelative(dir, path);
 
     const auto size_file = relative_dir->GetFile(GetSaveDataSizeFileName());
@@ -220,7 +221,7 @@ SaveDataSize SaveDataFactory::ReadSaveDataSize(SaveDataType type, u64 title_id,
 void SaveDataFactory::WriteSaveDataSize(SaveDataType type, u64 title_id, u128 user_id,
                                         SaveDataSize new_value) const {
     const auto path =
-        GetFullPath(system, dir, SaveDataSpaceId::NandUser, type, title_id, user_id, 0);
+        GetFullPath(program_id, dir, SaveDataSpaceId::NandUser, type, title_id, user_id, 0);
     const auto relative_dir = GetOrCreateDirectoryRelative(dir, path);
 
     const auto size_file = relative_dir->CreateFile(GetSaveDataSizeFileName());
diff --git a/src/core/file_sys/savedata_factory.h b/src/core/file_sys/savedata_factory.h
index fd4887e99..30d96928e 100644
--- a/src/core/file_sys/savedata_factory.h
+++ b/src/core/file_sys/savedata_factory.h
@@ -87,10 +87,13 @@ constexpr const char* GetSaveDataSizeFileName() {
     return ".yuzu_save_size";
 }
 
+using ProgramId = u64;
+
 /// File system interface to the SaveData archive
 class SaveDataFactory {
 public:
-    explicit SaveDataFactory(Core::System& system_, VirtualDir save_directory_);
+    explicit SaveDataFactory(Core::System& system_, ProgramId program_id_,
+                             VirtualDir save_directory_);
     ~SaveDataFactory();
 
     VirtualDir Create(SaveDataSpaceId space, const SaveDataAttribute& meta) const;
@@ -99,7 +102,7 @@ public:
     VirtualDir GetSaveDataSpaceDirectory(SaveDataSpaceId space) const;
 
     static std::string GetSaveDataSpaceIdPath(SaveDataSpaceId space);
-    static std::string GetFullPath(Core::System& system, VirtualDir dir, SaveDataSpaceId space,
+    static std::string GetFullPath(ProgramId program_id, VirtualDir dir, SaveDataSpaceId space,
                                    SaveDataType type, u64 title_id, u128 user_id, u64 save_id);
     static std::string GetUserGameSaveDataRoot(u128 user_id, bool future);
 
@@ -110,8 +113,9 @@ public:
     void SetAutoCreate(bool state);
 
 private:
-    VirtualDir dir;
     Core::System& system;
+    ProgramId program_id;
+    VirtualDir dir;
     bool auto_create{true};
 };
 
diff --git a/src/core/hle/service/am/am.cpp b/src/core/hle/service/am/am.cpp
index 9e05bdafa..a768bdc54 100644
--- a/src/core/hle/service/am/am.cpp
+++ b/src/core/hle/service/am/am.cpp
@@ -36,6 +36,7 @@
 #include "core/hle/service/caps/caps_su.h"
 #include "core/hle/service/caps/caps_types.h"
 #include "core/hle/service/filesystem/filesystem.h"
+#include "core/hle/service/filesystem/save_data_controller.h"
 #include "core/hle/service/ipc_helpers.h"
 #include "core/hle/service/ns/ns.h"
 #include "core/hle/service/nvnflinger/fb_share_buffer_manager.h"
@@ -2178,7 +2179,7 @@ void IApplicationFunctions::EnsureSaveData(HLERequestContext& ctx) {
     attribute.type = FileSys::SaveDataType::SaveData;
 
     FileSys::VirtualDir save_data{};
-    const auto res = system.GetFileSystemController().CreateSaveData(
+    const auto res = system.GetFileSystemController().OpenSaveDataController()->CreateSaveData(
         &save_data, FileSys::SaveDataSpaceId::NandUser, attribute);
 
     IPC::ResponseBuilder rb{ctx, 4};
@@ -2353,7 +2354,7 @@ void IApplicationFunctions::ExtendSaveData(HLERequestContext& ctx) {
               "new_journal={:016X}",
               static_cast<u8>(type), user_id[1], user_id[0], new_normal_size, new_journal_size);
 
-    system.GetFileSystemController().WriteSaveDataSize(
+    system.GetFileSystemController().OpenSaveDataController()->WriteSaveDataSize(
         type, system.GetApplicationProcessProgramID(), user_id,
         {new_normal_size, new_journal_size});
 
@@ -2378,7 +2379,7 @@ void IApplicationFunctions::GetSaveDataSize(HLERequestContext& ctx) {
     LOG_DEBUG(Service_AM, "called with type={:02X}, user_id={:016X}{:016X}", type, user_id[1],
               user_id[0]);
 
-    const auto size = system.GetFileSystemController().ReadSaveDataSize(
+    const auto size = system.GetFileSystemController().OpenSaveDataController()->ReadSaveDataSize(
         type, system.GetApplicationProcessProgramID(), user_id);
 
     IPC::ResponseBuilder rb{ctx, 6};
diff --git a/src/core/hle/service/filesystem/filesystem.cpp b/src/core/hle/service/filesystem/filesystem.cpp
index 780f8c74d..ca6d8d607 100644
--- a/src/core/hle/service/filesystem/filesystem.cpp
+++ b/src/core/hle/service/filesystem/filesystem.cpp
@@ -24,15 +24,13 @@
 #include "core/hle/service/filesystem/fsp_ldr.h"
 #include "core/hle/service/filesystem/fsp_pr.h"
 #include "core/hle/service/filesystem/fsp_srv.h"
+#include "core/hle/service/filesystem/romfs_controller.h"
+#include "core/hle/service/filesystem/save_data_controller.h"
 #include "core/hle/service/server_manager.h"
 #include "core/loader/loader.h"
 
 namespace Service::FileSystem {
 
-// A default size for normal/journal save data size if application control metadata cannot be found.
-// This should be large enough to satisfy even the most extreme requirements (~4.2GB)
-constexpr u64 SUFFICIENT_SAVE_DATA_SIZE = 0xF0000000;
-
 static FileSys::VirtualDir GetDirectoryRelativeWrapped(FileSys::VirtualDir base,
                                                        std::string_view dir_name_) {
     std::string dir_name(Common::FS::SanitizePath(dir_name_));
@@ -297,145 +295,65 @@ FileSystemController::FileSystemController(Core::System& system_) : system{syste
 
 FileSystemController::~FileSystemController() = default;
 
-Result FileSystemController::RegisterRomFS(std::unique_ptr<FileSys::RomFSFactory>&& factory) {
-    romfs_factory = std::move(factory);
-    LOG_DEBUG(Service_FS, "Registered RomFS");
-    return ResultSuccess;
-}
-
-Result FileSystemController::RegisterSaveData(std::unique_ptr<FileSys::SaveDataFactory>&& factory) {
-    ASSERT_MSG(save_data_factory == nullptr, "Tried to register a second save data");
-    save_data_factory = std::move(factory);
-    LOG_DEBUG(Service_FS, "Registered save data");
-    return ResultSuccess;
-}
+Result FileSystemController::RegisterProcess(
+    ProcessId process_id, ProgramId program_id,
+    std::shared_ptr<FileSys::RomFSFactory>&& romfs_factory) {
+    std::scoped_lock lk{registration_lock};
 
-Result FileSystemController::RegisterSDMC(std::unique_ptr<FileSys::SDMCFactory>&& factory) {
-    ASSERT_MSG(sdmc_factory == nullptr, "Tried to register a second SDMC");
-    sdmc_factory = std::move(factory);
-    LOG_DEBUG(Service_FS, "Registered SDMC");
-    return ResultSuccess;
-}
+    registrations.emplace(process_id, Registration{
+                                          .program_id = program_id,
+                                          .romfs_factory = std::move(romfs_factory),
+                                          .save_data_factory = CreateSaveDataFactory(program_id),
+                                      });
 
-Result FileSystemController::RegisterBIS(std::unique_ptr<FileSys::BISFactory>&& factory) {
-    ASSERT_MSG(bis_factory == nullptr, "Tried to register a second BIS");
-    bis_factory = std::move(factory);
-    LOG_DEBUG(Service_FS, "Registered BIS");
+    LOG_DEBUG(Service_FS, "Registered for process {}", process_id);
     return ResultSuccess;
 }
 
-void FileSystemController::SetPackedUpdate(FileSys::VirtualFile update_raw) {
-    LOG_TRACE(Service_FS, "Setting packed update for romfs");
-
-    if (romfs_factory == nullptr)
-        return;
-
-    romfs_factory->SetPackedUpdate(std::move(update_raw));
-}
-
-FileSys::VirtualFile FileSystemController::OpenRomFSCurrentProcess() const {
-    LOG_TRACE(Service_FS, "Opening RomFS for current process");
-
-    if (romfs_factory == nullptr) {
-        return nullptr;
-    }
-
-    return romfs_factory->OpenCurrentProcess(system.GetApplicationProcessProgramID());
-}
-
-FileSys::VirtualFile FileSystemController::OpenPatchedRomFS(u64 title_id,
-                                                            FileSys::ContentRecordType type) const {
-    LOG_TRACE(Service_FS, "Opening patched RomFS for title_id={:016X}", title_id);
-
-    if (romfs_factory == nullptr) {
-        return nullptr;
-    }
-
-    return romfs_factory->OpenPatchedRomFS(title_id, type);
-}
-
-FileSys::VirtualFile FileSystemController::OpenPatchedRomFSWithProgramIndex(
-    u64 title_id, u8 program_index, FileSys::ContentRecordType type) const {
-    LOG_TRACE(Service_FS, "Opening patched RomFS for title_id={:016X}, program_index={}", title_id,
-              program_index);
-
-    if (romfs_factory == nullptr) {
-        return nullptr;
-    }
-
-    return romfs_factory->OpenPatchedRomFSWithProgramIndex(title_id, program_index, type);
-}
-
-FileSys::VirtualFile FileSystemController::OpenRomFS(u64 title_id, FileSys::StorageId storage_id,
-                                                     FileSys::ContentRecordType type) const {
-    LOG_TRACE(Service_FS, "Opening RomFS for title_id={:016X}, storage_id={:02X}, type={:02X}",
-              title_id, storage_id, type);
-
-    if (romfs_factory == nullptr) {
-        return nullptr;
-    }
-
-    return romfs_factory->Open(title_id, storage_id, type);
-}
-
-std::shared_ptr<FileSys::NCA> FileSystemController::OpenBaseNca(
-    u64 title_id, FileSys::StorageId storage_id, FileSys::ContentRecordType type) const {
-    return romfs_factory->GetEntry(title_id, storage_id, type);
-}
-
-Result FileSystemController::CreateSaveData(FileSys::VirtualDir* out_save_data,
-                                            FileSys::SaveDataSpaceId space,
-                                            const FileSys::SaveDataAttribute& save_struct) const {
-    LOG_TRACE(Service_FS, "Creating Save Data for space_id={:01X}, save_struct={}", space,
-              save_struct.DebugInfo());
+Result FileSystemController::OpenProcess(
+    ProgramId* out_program_id, std::shared_ptr<SaveDataController>* out_save_data_controller,
+    std::shared_ptr<RomFsController>* out_romfs_controller, ProcessId process_id) {
+    std::scoped_lock lk{registration_lock};
 
-    if (save_data_factory == nullptr) {
+    const auto it = registrations.find(process_id);
+    if (it == registrations.end()) {
         return FileSys::ERROR_ENTITY_NOT_FOUND;
     }
 
-    auto save_data = save_data_factory->Create(space, save_struct);
-    if (save_data == nullptr) {
-        return FileSys::ERROR_ENTITY_NOT_FOUND;
-    }
-
-    *out_save_data = save_data;
+    *out_program_id = it->second.program_id;
+    *out_save_data_controller =
+        std::make_shared<SaveDataController>(system, it->second.save_data_factory);
+    *out_romfs_controller =
+        std::make_shared<RomFsController>(it->second.romfs_factory, it->second.program_id);
     return ResultSuccess;
 }
 
-Result FileSystemController::OpenSaveData(FileSys::VirtualDir* out_save_data,
-                                          FileSys::SaveDataSpaceId space,
-                                          const FileSys::SaveDataAttribute& attribute) const {
-    LOG_TRACE(Service_FS, "Opening Save Data for space_id={:01X}, save_struct={}", space,
-              attribute.DebugInfo());
-
-    if (save_data_factory == nullptr) {
-        return FileSys::ERROR_ENTITY_NOT_FOUND;
-    }
+void FileSystemController::SetPackedUpdate(ProcessId process_id, FileSys::VirtualFile update_raw) {
+    LOG_TRACE(Service_FS, "Setting packed update for romfs");
 
-    auto save_data = save_data_factory->Open(space, attribute);
-    if (save_data == nullptr) {
-        return FileSys::ERROR_ENTITY_NOT_FOUND;
+    std::scoped_lock lk{registration_lock};
+    const auto it = registrations.find(process_id);
+    if (it == registrations.end()) {
+        return;
     }
 
-    *out_save_data = save_data;
-    return ResultSuccess;
+    it->second.romfs_factory->SetPackedUpdate(std::move(update_raw));
 }
 
-Result FileSystemController::OpenSaveDataSpace(FileSys::VirtualDir* out_save_data_space,
-                                               FileSys::SaveDataSpaceId space) const {
-    LOG_TRACE(Service_FS, "Opening Save Data Space for space_id={:01X}", space);
-
-    if (save_data_factory == nullptr) {
-        return FileSys::ERROR_ENTITY_NOT_FOUND;
-    }
+std::shared_ptr<SaveDataController> FileSystemController::OpenSaveDataController() {
+    return std::make_shared<SaveDataController>(system, CreateSaveDataFactory(ProgramId{}));
+}
 
-    auto save_data_space = save_data_factory->GetSaveDataSpaceDirectory(space);
-    if (save_data_space == nullptr) {
-        return FileSys::ERROR_ENTITY_NOT_FOUND;
-    }
+std::shared_ptr<FileSys::SaveDataFactory> FileSystemController::CreateSaveDataFactory(
+    ProgramId program_id) {
+    using YuzuPath = Common::FS::YuzuPath;
+    const auto rw_mode = FileSys::Mode::ReadWrite;
 
-    *out_save_data_space = save_data_space;
-    return ResultSuccess;
+    auto vfs = system.GetFilesystem();
+    const auto nand_directory =
+        vfs->OpenDirectory(Common::FS::GetYuzuPathString(YuzuPath::NANDDir), rw_mode);
+    return std::make_shared<FileSys::SaveDataFactory>(system, program_id,
+                                                      std::move(nand_directory));
 }
 
 Result FileSystemController::OpenSDMC(FileSys::VirtualDir* out_sdmc) const {
@@ -540,48 +458,6 @@ u64 FileSystemController::GetTotalSpaceSize(FileSys::StorageId id) const {
     return 0;
 }
 
-FileSys::SaveDataSize FileSystemController::ReadSaveDataSize(FileSys::SaveDataType type,
-                                                             u64 title_id, u128 user_id) const {
-    if (save_data_factory == nullptr) {
-        return {0, 0};
-    }
-
-    const auto value = save_data_factory->ReadSaveDataSize(type, title_id, user_id);
-
-    if (value.normal == 0 && value.journal == 0) {
-        FileSys::SaveDataSize new_size{SUFFICIENT_SAVE_DATA_SIZE, SUFFICIENT_SAVE_DATA_SIZE};
-
-        FileSys::NACP nacp;
-        const auto res = system.GetAppLoader().ReadControlData(nacp);
-
-        if (res != Loader::ResultStatus::Success) {
-            const FileSys::PatchManager pm{system.GetApplicationProcessProgramID(),
-                                           system.GetFileSystemController(),
-                                           system.GetContentProvider()};
-            const auto metadata = pm.GetControlMetadata();
-            const auto& nacp_unique = metadata.first;
-
-            if (nacp_unique != nullptr) {
-                new_size = {nacp_unique->GetDefaultNormalSaveSize(),
-                            nacp_unique->GetDefaultJournalSaveSize()};
-            }
-        } else {
-            new_size = {nacp.GetDefaultNormalSaveSize(), nacp.GetDefaultJournalSaveSize()};
-        }
-
-        WriteSaveDataSize(type, title_id, user_id, new_size);
-        return new_size;
-    }
-
-    return value;
-}
-
-void FileSystemController::WriteSaveDataSize(FileSys::SaveDataType type, u64 title_id, u128 user_id,
-                                             FileSys::SaveDataSize new_value) const {
-    if (save_data_factory != nullptr)
-        save_data_factory->WriteSaveDataSize(type, title_id, user_id, new_value);
-}
-
 void FileSystemController::SetGameCard(FileSys::VirtualFile file) {
     gamecard = std::make_unique<FileSys::XCI>(file);
     const auto dir = gamecard->ConcatenatedPseudoDirectory();
@@ -801,14 +677,9 @@ FileSys::VirtualDir FileSystemController::GetBCATDirectory(u64 title_id) const {
     return bis_factory->GetBCATDirectory(title_id);
 }
 
-void FileSystemController::SetAutoSaveDataCreation(bool enable) {
-    save_data_factory->SetAutoCreate(enable);
-}
-
 void FileSystemController::CreateFactories(FileSys::VfsFilesystem& vfs, bool overwrite) {
     if (overwrite) {
         bis_factory = nullptr;
-        save_data_factory = nullptr;
         sdmc_factory = nullptr;
     }
 
@@ -836,11 +707,6 @@ void FileSystemController::CreateFactories(FileSys::VfsFilesystem& vfs, bool ove
                                        bis_factory->GetUserNANDContents());
     }
 
-    if (save_data_factory == nullptr) {
-        save_data_factory =
-            std::make_unique<FileSys::SaveDataFactory>(system, std::move(nand_directory));
-    }
-
     if (sdmc_factory == nullptr) {
         sdmc_factory = std::make_unique<FileSys::SDMCFactory>(std::move(sd_directory),
                                                               std::move(sd_load_directory));
@@ -849,12 +715,19 @@ void FileSystemController::CreateFactories(FileSys::VfsFilesystem& vfs, bool ove
     }
 }
 
+void FileSystemController::Reset() {
+    std::scoped_lock lk{registration_lock};
+    registrations.clear();
+}
+
 void LoopProcess(Core::System& system) {
     auto server_manager = std::make_unique<ServerManager>(system);
 
+    const auto FileSystemProxyFactory = [&] { return std::make_shared<FSP_SRV>(system); };
+
     server_manager->RegisterNamedService("fsp-ldr", std::make_shared<FSP_LDR>(system));
     server_manager->RegisterNamedService("fsp:pr", std::make_shared<FSP_PR>(system));
-    server_manager->RegisterNamedService("fsp-srv", std::make_shared<FSP_SRV>(system));
+    server_manager->RegisterNamedService("fsp-srv", std::move(FileSystemProxyFactory));
     ServerManager::RunServer(std::move(server_manager));
 }
 
diff --git a/src/core/hle/service/filesystem/filesystem.h b/src/core/hle/service/filesystem/filesystem.h
index 276d264e1..48f37d289 100644
--- a/src/core/hle/service/filesystem/filesystem.h
+++ b/src/core/hle/service/filesystem/filesystem.h
@@ -43,6 +43,9 @@ class ServiceManager;
 
 namespace FileSystem {
 
+class RomFsController;
+class SaveDataController;
+
 enum class ContentStorageId : u32 {
     System,
     User,
@@ -61,32 +64,24 @@ enum class OpenDirectoryMode : u64 {
 };
 DECLARE_ENUM_FLAG_OPERATORS(OpenDirectoryMode);
 
+using ProcessId = u64;
+using ProgramId = u64;
+
 class FileSystemController {
 public:
     explicit FileSystemController(Core::System& system_);
     ~FileSystemController();
 
-    Result RegisterRomFS(std::unique_ptr<FileSys::RomFSFactory>&& factory);
-    Result RegisterSaveData(std::unique_ptr<FileSys::SaveDataFactory>&& factory);
-    Result RegisterSDMC(std::unique_ptr<FileSys::SDMCFactory>&& factory);
-    Result RegisterBIS(std::unique_ptr<FileSys::BISFactory>&& factory);
-
-    void SetPackedUpdate(FileSys::VirtualFile update_raw);
-    FileSys::VirtualFile OpenRomFSCurrentProcess() const;
-    FileSys::VirtualFile OpenPatchedRomFS(u64 title_id, FileSys::ContentRecordType type) const;
-    FileSys::VirtualFile OpenPatchedRomFSWithProgramIndex(u64 title_id, u8 program_index,
-                                                          FileSys::ContentRecordType type) const;
-    FileSys::VirtualFile OpenRomFS(u64 title_id, FileSys::StorageId storage_id,
-                                   FileSys::ContentRecordType type) const;
-    std::shared_ptr<FileSys::NCA> OpenBaseNca(u64 title_id, FileSys::StorageId storage_id,
-                                              FileSys::ContentRecordType type) const;
-
-    Result CreateSaveData(FileSys::VirtualDir* out_save_data, FileSys::SaveDataSpaceId space,
-                          const FileSys::SaveDataAttribute& save_struct) const;
-    Result OpenSaveData(FileSys::VirtualDir* out_save_data, FileSys::SaveDataSpaceId space,
-                        const FileSys::SaveDataAttribute& save_struct) const;
-    Result OpenSaveDataSpace(FileSys::VirtualDir* out_save_data_space,
-                             FileSys::SaveDataSpaceId space) const;
+    Result RegisterProcess(ProcessId process_id, ProgramId program_id,
+                           std::shared_ptr<FileSys::RomFSFactory>&& factory);
+    Result OpenProcess(ProgramId* out_program_id,
+                       std::shared_ptr<SaveDataController>* out_save_data_controller,
+                       std::shared_ptr<RomFsController>* out_romfs_controller,
+                       ProcessId process_id);
+    void SetPackedUpdate(ProcessId process_id, FileSys::VirtualFile update_raw);
+
+    std::shared_ptr<SaveDataController> OpenSaveDataController();
+
     Result OpenSDMC(FileSys::VirtualDir* out_sdmc) const;
     Result OpenBISPartition(FileSys::VirtualDir* out_bis_partition,
                             FileSys::BisPartitionId id) const;
@@ -96,11 +91,6 @@ public:
     u64 GetFreeSpaceSize(FileSys::StorageId id) const;
     u64 GetTotalSpaceSize(FileSys::StorageId id) const;
 
-    FileSys::SaveDataSize ReadSaveDataSize(FileSys::SaveDataType type, u64 title_id,
-                                           u128 user_id) const;
-    void WriteSaveDataSize(FileSys::SaveDataType type, u64 title_id, u128 user_id,
-                           FileSys::SaveDataSize new_value) const;
-
     void SetGameCard(FileSys::VirtualFile file);
     FileSys::XCI* GetGameCard() const;
 
@@ -133,15 +123,24 @@ public:
 
     FileSys::VirtualDir GetBCATDirectory(u64 title_id) const;
 
-    void SetAutoSaveDataCreation(bool enable);
-
     // Creates the SaveData, SDMC, and BIS Factories. Should be called once and before any function
     // above is called.
     void CreateFactories(FileSys::VfsFilesystem& vfs, bool overwrite = true);
 
+    void Reset();
+
 private:
-    std::unique_ptr<FileSys::RomFSFactory> romfs_factory;
-    std::unique_ptr<FileSys::SaveDataFactory> save_data_factory;
+    std::shared_ptr<FileSys::SaveDataFactory> CreateSaveDataFactory(ProgramId program_id);
+
+    struct Registration {
+        ProgramId program_id;
+        std::shared_ptr<FileSys::RomFSFactory> romfs_factory;
+        std::shared_ptr<FileSys::SaveDataFactory> save_data_factory;
+    };
+
+    std::mutex registration_lock;
+    std::map<ProcessId, Registration> registrations;
+
     std::unique_ptr<FileSys::SDMCFactory> sdmc_factory;
     std::unique_ptr<FileSys::BISFactory> bis_factory;
 
diff --git a/src/core/hle/service/filesystem/fsp_srv.cpp b/src/core/hle/service/filesystem/fsp_srv.cpp
index 82ecc1b90..a2397bec4 100644
--- a/src/core/hle/service/filesystem/fsp_srv.cpp
+++ b/src/core/hle/service/filesystem/fsp_srv.cpp
@@ -27,6 +27,8 @@
 #include "core/hle/result.h"
 #include "core/hle/service/filesystem/filesystem.h"
 #include "core/hle/service/filesystem/fsp_srv.h"
+#include "core/hle/service/filesystem/romfs_controller.h"
+#include "core/hle/service/filesystem/save_data_controller.h"
 #include "core/hle/service/hle_ipc.h"
 #include "core/hle/service/ipc_helpers.h"
 #include "core/reporter.h"
@@ -577,9 +579,11 @@ private:
 
 class ISaveDataInfoReader final : public ServiceFramework<ISaveDataInfoReader> {
 public:
-    explicit ISaveDataInfoReader(Core::System& system_, FileSys::SaveDataSpaceId space,
-                                 FileSystemController& fsc_)
-        : ServiceFramework{system_, "ISaveDataInfoReader"}, fsc{fsc_} {
+    explicit ISaveDataInfoReader(Core::System& system_,
+                                 std::shared_ptr<SaveDataController> save_data_controller_,
+                                 FileSys::SaveDataSpaceId space)
+        : ServiceFramework{system_, "ISaveDataInfoReader"}, save_data_controller{
+                                                                save_data_controller_} {
         static const FunctionInfo functions[] = {
             {0, &ISaveDataInfoReader::ReadSaveDataInfo, "ReadSaveDataInfo"},
         };
@@ -626,7 +630,7 @@ private:
 
     void FindAllSaves(FileSys::SaveDataSpaceId space) {
         FileSys::VirtualDir save_root{};
-        const auto result = fsc.OpenSaveDataSpace(&save_root, space);
+        const auto result = save_data_controller->OpenSaveDataSpace(&save_root, space);
 
         if (result != ResultSuccess || save_root == nullptr) {
             LOG_ERROR(Service_FS, "The save root for the space_id={:02X} was invalid!", space);
@@ -723,7 +727,8 @@ private:
     };
     static_assert(sizeof(SaveDataInfo) == 0x60, "SaveDataInfo has incorrect size.");
 
-    FileSystemController& fsc;
+    ProcessId process_id = 0;
+    std::shared_ptr<SaveDataController> save_data_controller;
     std::vector<SaveDataInfo> info;
     u64 next_entry_index = 0;
 };
@@ -863,21 +868,20 @@ FSP_SRV::FSP_SRV(Core::System& system_)
     if (Settings::values.enable_fs_access_log) {
         access_log_mode = AccessLogMode::SdCard;
     }
-
-    // This should be true on creation
-    fsc.SetAutoSaveDataCreation(true);
 }
 
 FSP_SRV::~FSP_SRV() = default;
 
 void FSP_SRV::SetCurrentProcess(HLERequestContext& ctx) {
-    IPC::RequestParser rp{ctx};
-    current_process_id = rp.Pop<u64>();
+    current_process_id = ctx.GetPID();
 
     LOG_DEBUG(Service_FS, "called. current_process_id=0x{:016X}", current_process_id);
 
+    const auto res =
+        fsc.OpenProcess(&program_id, &save_data_controller, &romfs_controller, current_process_id);
+
     IPC::ResponseBuilder rb{ctx, 2};
-    rb.Push(ResultSuccess);
+    rb.Push(res);
 }
 
 void FSP_SRV::OpenFileSystemWithPatch(HLERequestContext& ctx) {
@@ -916,7 +920,8 @@ void FSP_SRV::CreateSaveDataFileSystem(HLERequestContext& ctx) {
               uid[1], uid[0]);
 
     FileSys::VirtualDir save_data_dir{};
-    fsc.CreateSaveData(&save_data_dir, FileSys::SaveDataSpaceId::NandUser, save_struct);
+    save_data_controller->CreateSaveData(&save_data_dir, FileSys::SaveDataSpaceId::NandUser,
+                                         save_struct);
 
     IPC::ResponseBuilder rb{ctx, 2};
     rb.Push(ResultSuccess);
@@ -931,7 +936,8 @@ void FSP_SRV::CreateSaveDataFileSystemBySystemSaveDataId(HLERequestContext& ctx)
     LOG_DEBUG(Service_FS, "called save_struct = {}", save_struct.DebugInfo());
 
     FileSys::VirtualDir save_data_dir{};
-    fsc.CreateSaveData(&save_data_dir, FileSys::SaveDataSpaceId::NandSystem, save_struct);
+    save_data_controller->CreateSaveData(&save_data_dir, FileSys::SaveDataSpaceId::NandSystem,
+                                         save_struct);
 
     IPC::ResponseBuilder rb{ctx, 2};
     rb.Push(ResultSuccess);
@@ -950,7 +956,8 @@ void FSP_SRV::OpenSaveDataFileSystem(HLERequestContext& ctx) {
     LOG_INFO(Service_FS, "called.");
 
     FileSys::VirtualDir dir{};
-    auto result = fsc.OpenSaveData(&dir, parameters.space_id, parameters.attribute);
+    auto result =
+        save_data_controller->OpenSaveData(&dir, parameters.space_id, parameters.attribute);
     if (result != ResultSuccess) {
         IPC::ResponseBuilder rb{ctx, 2, 0, 0};
         rb.Push(FileSys::ERROR_ENTITY_NOT_FOUND);
@@ -1001,7 +1008,7 @@ void FSP_SRV::OpenSaveDataInfoReaderBySaveDataSpaceId(HLERequestContext& ctx) {
     IPC::ResponseBuilder rb{ctx, 2, 0, 1};
     rb.Push(ResultSuccess);
     rb.PushIpcInterface<ISaveDataInfoReader>(
-        std::make_shared<ISaveDataInfoReader>(system, space, fsc));
+        std::make_shared<ISaveDataInfoReader>(system, save_data_controller, space));
 }
 
 void FSP_SRV::OpenSaveDataInfoReaderOnlyCacheStorage(HLERequestContext& ctx) {
@@ -1009,8 +1016,8 @@ void FSP_SRV::OpenSaveDataInfoReaderOnlyCacheStorage(HLERequestContext& ctx) {
 
     IPC::ResponseBuilder rb{ctx, 2, 0, 1};
     rb.Push(ResultSuccess);
-    rb.PushIpcInterface<ISaveDataInfoReader>(system, FileSys::SaveDataSpaceId::TemporaryStorage,
-                                             fsc);
+    rb.PushIpcInterface<ISaveDataInfoReader>(system, save_data_controller,
+                                             FileSys::SaveDataSpaceId::TemporaryStorage);
 }
 
 void FSP_SRV::WriteSaveDataFileSystemExtraDataBySaveDataAttribute(HLERequestContext& ctx) {
@@ -1050,7 +1057,7 @@ void FSP_SRV::OpenDataStorageByCurrentProcess(HLERequestContext& ctx) {
     LOG_DEBUG(Service_FS, "called");
 
     if (!romfs) {
-        auto current_romfs = fsc.OpenRomFSCurrentProcess();
+        auto current_romfs = romfs_controller->OpenRomFSCurrentProcess();
         if (!current_romfs) {
             // TODO (bunnei): Find the right error code to use here
             LOG_CRITICAL(Service_FS, "no file system interface available!");
@@ -1078,7 +1085,7 @@ void FSP_SRV::OpenDataStorageByDataId(HLERequestContext& ctx) {
     LOG_DEBUG(Service_FS, "called with storage_id={:02X}, unknown={:08X}, title_id={:016X}",
               storage_id, unknown, title_id);
 
-    auto data = fsc.OpenRomFS(title_id, storage_id, FileSys::ContentRecordType::Data);
+    auto data = romfs_controller->OpenRomFS(title_id, storage_id, FileSys::ContentRecordType::Data);
 
     if (!data) {
         const auto archive = FileSys::SystemArchive::SynthesizeSystemArchive(title_id);
@@ -1101,7 +1108,8 @@ void FSP_SRV::OpenDataStorageByDataId(HLERequestContext& ctx) {
 
     const FileSys::PatchManager pm{title_id, fsc, content_provider};
 
-    auto base = fsc.OpenBaseNca(title_id, storage_id, FileSys::ContentRecordType::Data);
+    auto base =
+        romfs_controller->OpenBaseNca(title_id, storage_id, FileSys::ContentRecordType::Data);
     auto storage = std::make_shared<IStorage>(
         system, pm.PatchRomFS(base.get(), std::move(data), FileSys::ContentRecordType::Data));
 
@@ -1129,9 +1137,8 @@ void FSP_SRV::OpenDataStorageWithProgramIndex(HLERequestContext& ctx) {
 
     LOG_DEBUG(Service_FS, "called, program_index={}", program_index);
 
-    auto patched_romfs =
-        fsc.OpenPatchedRomFSWithProgramIndex(system.GetApplicationProcessProgramID(), program_index,
-                                             FileSys::ContentRecordType::Program);
+    auto patched_romfs = romfs_controller->OpenPatchedRomFSWithProgramIndex(
+        program_id, program_index, FileSys::ContentRecordType::Program);
 
     if (!patched_romfs) {
         // TODO: Find the right error code to use here
@@ -1152,7 +1159,7 @@ void FSP_SRV::OpenDataStorageWithProgramIndex(HLERequestContext& ctx) {
 void FSP_SRV::DisableAutoSaveDataCreation(HLERequestContext& ctx) {
     LOG_DEBUG(Service_FS, "called");
 
-    fsc.SetAutoSaveDataCreation(false);
+    save_data_controller->SetAutoCreate(false);
 
     IPC::ResponseBuilder rb{ctx, 2};
     rb.Push(ResultSuccess);
diff --git a/src/core/hle/service/filesystem/fsp_srv.h b/src/core/hle/service/filesystem/fsp_srv.h
index 280bc9867..26980af99 100644
--- a/src/core/hle/service/filesystem/fsp_srv.h
+++ b/src/core/hle/service/filesystem/fsp_srv.h
@@ -17,6 +17,9 @@ class FileSystemBackend;
 
 namespace Service::FileSystem {
 
+class RomFsController;
+class SaveDataController;
+
 enum class AccessLogVersion : u32 {
     V7_0_0 = 2,
 
@@ -67,6 +70,9 @@ private:
     u64 current_process_id = 0;
     u32 access_log_program_index = 0;
     AccessLogMode access_log_mode = AccessLogMode::None;
+    u64 program_id = 0;
+    std::shared_ptr<SaveDataController> save_data_controller;
+    std::shared_ptr<RomFsController> romfs_controller;
 };
 
 } // namespace Service::FileSystem
diff --git a/src/core/hle/service/filesystem/romfs_controller.cpp b/src/core/hle/service/filesystem/romfs_controller.cpp
new file mode 100644
index 000000000..19c9cec72
--- /dev/null
+++ b/src/core/hle/service/filesystem/romfs_controller.cpp
@@ -0,0 +1,37 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/hle/service/filesystem/romfs_controller.h"
+
+namespace Service::FileSystem {
+
+RomFsController::RomFsController(std::shared_ptr<FileSys::RomFSFactory> factory_, u64 program_id_)
+    : factory{std::move(factory_)}, program_id{program_id_} {}
+RomFsController::~RomFsController() = default;
+
+FileSys::VirtualFile RomFsController::OpenRomFSCurrentProcess() {
+    return factory->OpenCurrentProcess(program_id);
+}
+
+FileSys::VirtualFile RomFsController::OpenPatchedRomFS(u64 title_id,
+                                                       FileSys::ContentRecordType type) {
+    return factory->OpenPatchedRomFS(title_id, type);
+}
+
+FileSys::VirtualFile RomFsController::OpenPatchedRomFSWithProgramIndex(
+    u64 title_id, u8 program_index, FileSys::ContentRecordType type) {
+    return factory->OpenPatchedRomFSWithProgramIndex(title_id, program_index, type);
+}
+
+FileSys::VirtualFile RomFsController::OpenRomFS(u64 title_id, FileSys::StorageId storage_id,
+                                                FileSys::ContentRecordType type) {
+    return factory->Open(title_id, storage_id, type);
+}
+
+std::shared_ptr<FileSys::NCA> RomFsController::OpenBaseNca(u64 title_id,
+                                                           FileSys::StorageId storage_id,
+                                                           FileSys::ContentRecordType type) {
+    return factory->GetEntry(title_id, storage_id, type);
+}
+
+} // namespace Service::FileSystem
diff --git a/src/core/hle/service/filesystem/romfs_controller.h b/src/core/hle/service/filesystem/romfs_controller.h
new file mode 100644
index 000000000..9a478f71d
--- /dev/null
+++ b/src/core/hle/service/filesystem/romfs_controller.h
@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/file_sys/nca_metadata.h"
+#include "core/file_sys/romfs_factory.h"
+#include "core/file_sys/vfs_types.h"
+
+namespace Service::FileSystem {
+
+class RomFsController {
+public:
+    explicit RomFsController(std::shared_ptr<FileSys::RomFSFactory> factory_, u64 program_id_);
+    ~RomFsController();
+
+    FileSys::VirtualFile OpenRomFSCurrentProcess();
+    FileSys::VirtualFile OpenPatchedRomFS(u64 title_id, FileSys::ContentRecordType type);
+    FileSys::VirtualFile OpenPatchedRomFSWithProgramIndex(u64 title_id, u8 program_index,
+                                                          FileSys::ContentRecordType type);
+    FileSys::VirtualFile OpenRomFS(u64 title_id, FileSys::StorageId storage_id,
+                                   FileSys::ContentRecordType type);
+    std::shared_ptr<FileSys::NCA> OpenBaseNca(u64 title_id, FileSys::StorageId storage_id,
+                                              FileSys::ContentRecordType type);
+
+private:
+    const std::shared_ptr<FileSys::RomFSFactory> factory;
+    const u64 program_id;
+};
+
+} // namespace Service::FileSystem
diff --git a/src/core/hle/service/filesystem/save_data_controller.cpp b/src/core/hle/service/filesystem/save_data_controller.cpp
new file mode 100644
index 000000000..d19b3ea1e
--- /dev/null
+++ b/src/core/hle/service/filesystem/save_data_controller.cpp
@@ -0,0 +1,99 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "core/core.h"
+#include "core/file_sys/control_metadata.h"
+#include "core/file_sys/errors.h"
+#include "core/file_sys/patch_manager.h"
+#include "core/hle/service/filesystem/save_data_controller.h"
+#include "core/loader/loader.h"
+
+namespace Service::FileSystem {
+
+namespace {
+
+// A default size for normal/journal save data size if application control metadata cannot be found.
+// This should be large enough to satisfy even the most extreme requirements (~4.2GB)
+constexpr u64 SufficientSaveDataSize = 0xF0000000;
+
+FileSys::SaveDataSize GetDefaultSaveDataSize(Core::System& system, u64 program_id) {
+    const FileSys::PatchManager pm{program_id, system.GetFileSystemController(),
+                                   system.GetContentProvider()};
+    const auto metadata = pm.GetControlMetadata();
+    const auto& nacp = metadata.first;
+
+    if (nacp != nullptr) {
+        return {nacp->GetDefaultNormalSaveSize(), nacp->GetDefaultJournalSaveSize()};
+    }
+
+    return {SufficientSaveDataSize, SufficientSaveDataSize};
+}
+
+} // namespace
+
+SaveDataController::SaveDataController(Core::System& system_,
+                                       std::shared_ptr<FileSys::SaveDataFactory> factory_)
+    : system{system_}, factory{std::move(factory_)} {}
+SaveDataController::~SaveDataController() = default;
+
+Result SaveDataController::CreateSaveData(FileSys::VirtualDir* out_save_data,
+                                          FileSys::SaveDataSpaceId space,
+                                          const FileSys::SaveDataAttribute& attribute) {
+    LOG_TRACE(Service_FS, "Creating Save Data for space_id={:01X}, save_struct={}", space,
+              attribute.DebugInfo());
+
+    auto save_data = factory->Create(space, attribute);
+    if (save_data == nullptr) {
+        return FileSys::ERROR_ENTITY_NOT_FOUND;
+    }
+
+    *out_save_data = save_data;
+    return ResultSuccess;
+}
+
+Result SaveDataController::OpenSaveData(FileSys::VirtualDir* out_save_data,
+                                        FileSys::SaveDataSpaceId space,
+                                        const FileSys::SaveDataAttribute& attribute) {
+    auto save_data = factory->Open(space, attribute);
+    if (save_data == nullptr) {
+        return FileSys::ERROR_ENTITY_NOT_FOUND;
+    }
+
+    *out_save_data = save_data;
+    return ResultSuccess;
+}
+
+Result SaveDataController::OpenSaveDataSpace(FileSys::VirtualDir* out_save_data_space,
+                                             FileSys::SaveDataSpaceId space) {
+    auto save_data_space = factory->GetSaveDataSpaceDirectory(space);
+    if (save_data_space == nullptr) {
+        return FileSys::ERROR_ENTITY_NOT_FOUND;
+    }
+
+    *out_save_data_space = save_data_space;
+    return ResultSuccess;
+}
+
+FileSys::SaveDataSize SaveDataController::ReadSaveDataSize(FileSys::SaveDataType type, u64 title_id,
+                                                           u128 user_id) {
+    const auto value = factory->ReadSaveDataSize(type, title_id, user_id);
+
+    if (value.normal == 0 && value.journal == 0) {
+        const auto size = GetDefaultSaveDataSize(system, title_id);
+        factory->WriteSaveDataSize(type, title_id, user_id, size);
+        return size;
+    }
+
+    return value;
+}
+
+void SaveDataController::WriteSaveDataSize(FileSys::SaveDataType type, u64 title_id, u128 user_id,
+                                           FileSys::SaveDataSize new_value) {
+    factory->WriteSaveDataSize(type, title_id, user_id, new_value);
+}
+
+void SaveDataController::SetAutoCreate(bool state) {
+    factory->SetAutoCreate(state);
+}
+
+} // namespace Service::FileSystem
diff --git a/src/core/hle/service/filesystem/save_data_controller.h b/src/core/hle/service/filesystem/save_data_controller.h
new file mode 100644
index 000000000..863188e4c
--- /dev/null
+++ b/src/core/hle/service/filesystem/save_data_controller.h
@@ -0,0 +1,35 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "core/file_sys/nca_metadata.h"
+#include "core/file_sys/savedata_factory.h"
+#include "core/file_sys/vfs_types.h"
+
+namespace Service::FileSystem {
+
+class SaveDataController {
+public:
+    explicit SaveDataController(Core::System& system,
+                                std::shared_ptr<FileSys::SaveDataFactory> factory_);
+    ~SaveDataController();
+
+    Result CreateSaveData(FileSys::VirtualDir* out_save_data, FileSys::SaveDataSpaceId space,
+                          const FileSys::SaveDataAttribute& attribute);
+    Result OpenSaveData(FileSys::VirtualDir* out_save_data, FileSys::SaveDataSpaceId space,
+                        const FileSys::SaveDataAttribute& attribute);
+    Result OpenSaveDataSpace(FileSys::VirtualDir* out_save_data_space,
+                             FileSys::SaveDataSpaceId space);
+
+    FileSys::SaveDataSize ReadSaveDataSize(FileSys::SaveDataType type, u64 title_id, u128 user_id);
+    void WriteSaveDataSize(FileSys::SaveDataType type, u64 title_id, u128 user_id,
+                           FileSys::SaveDataSize new_value);
+    void SetAutoCreate(bool state);
+
+private:
+    Core::System& system;
+    const std::shared_ptr<FileSys::SaveDataFactory> factory;
+};
+
+} // namespace Service::FileSystem
diff --git a/src/core/loader/deconstructed_rom_directory.cpp b/src/core/loader/deconstructed_rom_directory.cpp
index c9f8707b7..1e599e78b 100644
--- a/src/core/loader/deconstructed_rom_directory.cpp
+++ b/src/core/loader/deconstructed_rom_directory.cpp
@@ -216,20 +216,6 @@ AppLoader_DeconstructedRomDirectory::LoadResult AppLoader_DeconstructedRomDirect
         LOG_DEBUG(Loader, "loaded module {} @ {:#X}", module, load_addr);
     }
 
-    // Find the RomFS by searching for a ".romfs" file in this directory
-    const auto& files = dir->GetFiles();
-    const auto romfs_iter =
-        std::find_if(files.begin(), files.end(), [](const FileSys::VirtualFile& f) {
-            return f->GetName().find(".romfs") != std::string::npos;
-        });
-
-    // Register the RomFS if a ".romfs" file was found
-    if (romfs_iter != files.end() && *romfs_iter != nullptr) {
-        romfs = *romfs_iter;
-        system.GetFileSystemController().RegisterRomFS(std::make_unique<FileSys::RomFSFactory>(
-            *this, system.GetContentProvider(), system.GetFileSystemController()));
-    }
-
     is_loaded = true;
     return {ResultStatus::Success,
             LoadParameters{metadata.GetMainThreadPriority(), metadata.GetMainThreadStackSize()}};
diff --git a/src/core/loader/nca.cpp b/src/core/loader/nca.cpp
index 814407535..2a32b1276 100644
--- a/src/core/loader/nca.cpp
+++ b/src/core/loader/nca.cpp
@@ -74,8 +74,10 @@ AppLoader_NCA::LoadResult AppLoader_NCA::Load(Kernel::KProcess& process, Core::S
         return load_result;
     }
 
-    system.GetFileSystemController().RegisterRomFS(std::make_unique<FileSys::RomFSFactory>(
-        *this, system.GetContentProvider(), system.GetFileSystemController()));
+    system.GetFileSystemController().RegisterProcess(
+        process.GetProcessId(), nca->GetTitleId(),
+        std::make_shared<FileSys::RomFSFactory>(*this, system.GetContentProvider(),
+                                                system.GetFileSystemController()));
 
     is_loaded = true;
     return load_result;
diff --git a/src/core/loader/nro.cpp b/src/core/loader/nro.cpp
index e74697cda..83371fcbd 100644
--- a/src/core/loader/nro.cpp
+++ b/src/core/loader/nro.cpp
@@ -276,8 +276,10 @@ AppLoader_NRO::LoadResult AppLoader_NRO::Load(Kernel::KProcess& process, Core::S
     }
 
     if (romfs != nullptr) {
-        system.GetFileSystemController().RegisterRomFS(std::make_unique<FileSys::RomFSFactory>(
-            *this, system.GetContentProvider(), system.GetFileSystemController()));
+        system.GetFileSystemController().RegisterProcess(
+            process.GetProcessId(), {},
+            std::make_unique<FileSys::RomFSFactory>(*this, system.GetContentProvider(),
+                                                    system.GetFileSystemController()));
     }
 
     is_loaded = true;
diff --git a/src/core/loader/nsp.cpp b/src/core/loader/nsp.cpp
index f4ab75b77..28116ff3a 100644
--- a/src/core/loader/nsp.cpp
+++ b/src/core/loader/nsp.cpp
@@ -111,7 +111,8 @@ AppLoader_NSP::LoadResult AppLoader_NSP::Load(Kernel::KProcess& process, Core::S
 
     FileSys::VirtualFile update_raw;
     if (ReadUpdateRaw(update_raw) == ResultStatus::Success && update_raw != nullptr) {
-        system.GetFileSystemController().SetPackedUpdate(std::move(update_raw));
+        system.GetFileSystemController().SetPackedUpdate(process.GetProcessId(),
+                                                         std::move(update_raw));
     }
 
     is_loaded = true;
diff --git a/src/core/loader/xci.cpp b/src/core/loader/xci.cpp
index 12d72c380..e9abb199a 100644
--- a/src/core/loader/xci.cpp
+++ b/src/core/loader/xci.cpp
@@ -78,7 +78,8 @@ AppLoader_XCI::LoadResult AppLoader_XCI::Load(Kernel::KProcess& process, Core::S
 
     FileSys::VirtualFile update_raw;
     if (ReadUpdateRaw(update_raw) == ResultStatus::Success && update_raw != nullptr) {
-        system.GetFileSystemController().SetPackedUpdate(std::move(update_raw));
+        system.GetFileSystemController().SetPackedUpdate(process.GetProcessId(),
+                                                         std::move(update_raw));
     }
 
     is_loaded = true;
diff --git a/src/yuzu/main.cpp b/src/yuzu/main.cpp
index 4f4c75f5c..29f47bf48 100644
--- a/src/yuzu/main.cpp
+++ b/src/yuzu/main.cpp
@@ -2292,14 +2292,14 @@ void GMainWindow::OnGameListOpenFolder(u64 program_id, GameListOpenTarget target
             ASSERT(user_id);
 
             const auto user_save_data_path = FileSys::SaveDataFactory::GetFullPath(
-                *system, vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser,
+                {}, vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser,
                 FileSys::SaveDataType::SaveData, program_id, user_id->AsU128(), 0);
 
             path = Common::FS::ConcatPathSafe(nand_dir, user_save_data_path);
         } else {
             // Device save data
             const auto device_save_data_path = FileSys::SaveDataFactory::GetFullPath(
-                *system, vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser,
+                {}, vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser,
                 FileSys::SaveDataType::SaveData, program_id, {}, 0);
 
             path = Common::FS::ConcatPathSafe(nand_dir, device_save_data_path);
@@ -2662,8 +2662,8 @@ void GMainWindow::RemoveCacheStorage(u64 program_id) {
         vfs->OpenDirectory(Common::FS::PathToUTF8String(nand_dir), FileSys::Mode::Read);
 
     const auto cache_storage_path = FileSys::SaveDataFactory::GetFullPath(
-        *system, vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser,
-        FileSys::SaveDataType::CacheStorage, 0 /* program_id */, {}, 0);
+        {}, vfs_nand_dir, FileSys::SaveDataSpaceId::NandUser, FileSys::SaveDataType::CacheStorage,
+        0 /* program_id */, {}, 0);
 
     const auto path = Common::FS::ConcatPathSafe(nand_dir, cache_storage_path);