diff --git a/src/LibHac/Fs/AccessLog.cs b/src/LibHac/Fs/AccessLog.cs
index 693766dc..bfed8313 100644
--- a/src/LibHac/Fs/AccessLog.cs
+++ b/src/LibHac/Fs/AccessLog.cs
@@ -1135,5 +1135,33 @@ namespace LibHac.Fs.Impl
                 (byte)',', (byte)' ', (byte)'f', (byte)'u', (byte)'n', (byte)'c', (byte)'t', (byte)'i',
                 (byte)'o', (byte)'n', (byte)':', (byte)' ', (byte)'"'
             };
+
+        /// <summary>"<c>, cachestoragelist_handle: 0x</c>"</summary>
+        public static ReadOnlySpan<byte> LogCacheStorageListHandle =>
+            new[]
+            {
+                (byte)',', (byte)' ', (byte)'c', (byte)'a', (byte)'c', (byte)'h', (byte)'e', (byte)'s',
+                (byte)'t', (byte)'o', (byte)'r', (byte)'a', (byte)'g', (byte)'e', (byte)'l', (byte)'i',
+                (byte)'s', (byte)'t', (byte)'_', (byte)'h', (byte)'a', (byte)'n', (byte)'d', (byte)'l',
+                (byte)'e', (byte)':', (byte)' ', (byte)'0', (byte)'x'
+            };
+
+        /// <summary>"<c>, infobuffercount: 0x</c>"</summary>
+        public static ReadOnlySpan<byte> LogInfoBufferCount =>
+            new[]
+            {
+                (byte)',', (byte)' ', (byte)'i', (byte)'n', (byte)'f', (byte)'o', (byte)'b', (byte)'u',
+                (byte)'f', (byte)'f', (byte)'e', (byte)'r', (byte)'c', (byte)'o', (byte)'u', (byte)'n',
+                (byte)'t', (byte)':', (byte)' ', (byte)'0', (byte)'x'
+            };
+
+        /// <summary>"<c>, cache_storage_count: </c>"</summary>
+        public static ReadOnlySpan<byte> LogCacheStorageCount =>
+            new[]
+            {
+                (byte)',', (byte)' ', (byte)'c', (byte)'a', (byte)'c', (byte)'h', (byte)'e', (byte)'_',
+                (byte)'s', (byte)'t', (byte)'o', (byte)'r', (byte)'a', (byte)'g', (byte)'e', (byte)'_',
+                (byte)'c', (byte)'o', (byte)'u', (byte)'n', (byte)'t', (byte)':', (byte)' '
+            };
     }
 }
\ No newline at end of file
diff --git a/src/LibHac/Fs/ApplicationSaveDataManagement.cs b/src/LibHac/Fs/ApplicationSaveDataManagement.cs
index 2e13c0d0..61e64ca4 100644
--- a/src/LibHac/Fs/ApplicationSaveDataManagement.cs
+++ b/src/LibHac/Fs/ApplicationSaveDataManagement.cs
@@ -29,7 +29,7 @@ public static class ApplicationSaveDataManagement
 
             Result CreateAccountSaveFunc()
             {
-                UserId userId = ConvertAccountUidToFsUserId(uidLocal);
+                UserId userId = Utility.ConvertAccountUidToFsUserId(uidLocal);
                 return fs.CreateSaveData(applicationId, userId, saveDataOwnerId, accountSaveDataSize,
                     accountSaveJournalSize, SaveDataFlags.None);
             }
@@ -465,9 +465,4 @@ public static class ApplicationSaveDataManagement
 
         return rc;
     }
-
-    public static UserId ConvertAccountUidToFsUserId(Uid uid)
-    {
-        return new UserId(uid.Id.High, uid.Id.Low);
-    }
 }
\ No newline at end of file
diff --git a/src/LibHac/Fs/CacheStorageTypes.cs b/src/LibHac/Fs/CacheStorageTypes.cs
new file mode 100644
index 00000000..d9b5eaa9
--- /dev/null
+++ b/src/LibHac/Fs/CacheStorageTypes.cs
@@ -0,0 +1,19 @@
+using LibHac.Common.FixedArrays;
+
+namespace LibHac.Fs;
+
+public readonly struct CacheStorageListHandle
+{
+    internal readonly object Cache;
+
+    internal CacheStorageListHandle(object cache)
+    {
+        Cache = cache;
+    }
+}
+
+public struct CacheStorageInfo
+{
+    public int Index;
+    public Array28<byte> Reserved;
+}
\ No newline at end of file
diff --git a/src/LibHac/Fs/Shim/SaveDataManagement.cs b/src/LibHac/Fs/Shim/SaveDataManagement.cs
index c785a48e..6c9444ba 100644
--- a/src/LibHac/Fs/Shim/SaveDataManagement.cs
+++ b/src/LibHac/Fs/Shim/SaveDataManagement.cs
@@ -1,5 +1,7 @@
 using System;
+using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using LibHac.Common;
 using LibHac.Diag;
 using LibHac.Fs.Fsa;
@@ -12,682 +14,290 @@ using LibHac.Sf;
 using LibHac.Time;
 using static LibHac.Fs.Impl.AccessLogStrings;
 
-namespace LibHac.Fs.Shim;
-
-public class SaveDataIterator : IDisposable
+namespace LibHac.Fs
 {
-    private readonly FileSystemClient _fsClient;
-    private SharedRef<ISaveDataInfoReader> _reader;
-
-    internal SaveDataIterator(FileSystemClient fsClient, ref SharedRef<ISaveDataInfoReader> reader)
+    /// <summary>
+    /// Allows iterating through the <see cref="SaveDataInfo"/> of a list of save data.
+    /// </summary>
+    /// <remarks>Based on nnSdk 13.4.0</remarks>
+    public class SaveDataIterator : IDisposable
     {
-        _reader = SharedRef<ISaveDataInfoReader>.CreateMove(ref reader);
-        _fsClient = fsClient;
-    }
+        private readonly FileSystemClient _fsClient;
+        private SharedRef<ISaveDataInfoReader> _reader;
 
-    public void Dispose()
-    {
-        _reader.Destroy();
-    }
-
-    private Result ReadSaveDataInfoImpl(out long readCount, Span<SaveDataInfo> buffer)
-    {
-        Result rc = _reader.Get.Read(out readCount, OutBuffer.FromSpan(buffer));
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    public Result ReadSaveDataInfo(out long readCount, Span<SaveDataInfo> buffer)
-    {
-        Result rc;
-        FileSystemClient fs = _fsClient;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        internal SaveDataIterator(FileSystemClient fsClient, ref SharedRef<ISaveDataInfoReader> reader)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = ReadSaveDataInfoImpl(out readCount, buffer);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSize).AppendFormat(buffer.Length, 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = ReadSaveDataInfoImpl(out readCount, buffer);
+            _reader = SharedRef<ISaveDataInfoReader>.CreateMove(ref reader);
+            _fsClient = fsClient;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        if (rc.IsFailure()) return rc.Miss();
+        public void Dispose()
+        {
+            _reader.Destroy();
+        }
 
-        return Result.Success;
+        private Result ReadSaveDataInfoImpl(out long readCount, Span<SaveDataInfo> buffer)
+        {
+            Result rc = _reader.Get.Read(out readCount, OutBuffer.FromSpan(buffer));
+            if (rc.IsFailure()) return rc.Miss();
+
+            return Result.Success;
+        }
+
+        public Result ReadSaveDataInfo(out long readCount, Span<SaveDataInfo> buffer)
+        {
+            Result rc;
+            FileSystemClient fs = _fsClient;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = ReadSaveDataInfoImpl(out readCount, buffer);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSize).AppendFormat(buffer.Length, 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = ReadSaveDataInfoImpl(out readCount, buffer);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc.Miss();
+
+            return Result.Success;
+        }
     }
 }
 
-[SkipLocalsInit]
-public static class SaveDataManagement
+namespace LibHac.Fs.Shim
 {
-    public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
-        out SaveDataExtraData extraData, ulong saveDataId)
-    {
-        UnsafeHelpers.SkipParamInit(out extraData);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraData(OutBuffer.FromStruct(ref extraData), saveDataId);
-        if (rc.IsFailure()) return rc;
-
-        return Result.Success;
-    }
-
-    public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
-        out SaveDataExtraData extraData, SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        UnsafeHelpers.SkipParamInit(out extraData);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraDataBySaveDataSpaceId(
-            OutBuffer.FromStruct(ref extraData), spaceId, saveDataId);
-        if (rc.IsFailure()) return rc;
-
-        return Result.Success;
-    }
-
-    public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
-        out SaveDataExtraData extraData, SaveDataSpaceId spaceId, in SaveDataAttribute attribute)
-    {
-        UnsafeHelpers.SkipParamInit(out extraData);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraDataBySaveDataAttribute(
-            OutBuffer.FromStruct(ref extraData), spaceId, in attribute);
-        if (rc.IsFailure()) return rc;
-
-        return Result.Success;
-    }
-
-    public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
-        out SaveDataExtraData extraData, SaveDataSpaceId spaceId, in SaveDataAttribute attribute,
-        in SaveDataExtraData extraDataMask)
-    {
-        UnsafeHelpers.SkipParamInit(out extraData);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraDataWithMaskBySaveDataAttribute(
-            OutBuffer.FromStruct(ref extraData), spaceId, in attribute, InBuffer.FromStruct(in extraDataMask));
-        if (rc.IsFailure()) return rc;
-
-        return Result.Success;
-    }
-
     /// <summary>
-    /// Writes the <see cref="SaveDataExtraData.Flags"/> of the provided <see cref="SaveDataExtraData"/>
-    /// to the save data in the specified <see cref="SaveDataSpaceId"/> with the provided save data ID.
+    /// Contains functions for creating, deleting, and otherwise managing save data.
     /// </summary>
-    /// <param name="fs">The <see cref="FileSystemClient"/> to use.</param>
-    /// <param name="spaceId">The <see cref="SaveDataSpaceId"/> containing the save data to be written to.</param>
-    /// <param name="saveDataId">The save data ID of the save data to be written to.</param>
-    /// <param name="extraData">The <see cref="SaveDataExtraData"/> containing the data to write.</param>
-    /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
-    /// <see cref="ResultFs.TargetNotFound"/>: The save data was not found.<br/>
-    /// <see cref="ResultFs.PermissionDenied"/>: Insufficient permissions.</returns>
-    public static Result WriteSaveDataFileSystemExtraData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId,
-        ulong saveDataId, in SaveDataExtraData extraData)
+    /// <remarks>Based on nnSdk 13.4.0</remarks>
+    [SkipLocalsInit]
+    public static class SaveDataManagement
     {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.WriteSaveDataFileSystemExtraData(saveDataId, spaceId,
-            InBuffer.FromStruct(in extraData));
-        fs.AbortIfNeeded(rc);
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    /// <summary>
-    /// Writes the provided <paramref name="extraData"/> to the save data in the specified
-    /// <see cref="SaveDataSpaceId"/> with the provided save data ID.
-    /// </summary>
-    /// <param name="fs">The <see cref="FileSystemClient"/> to use.</param>
-    /// <param name="spaceId">The <see cref="SaveDataSpaceId"/> containing the save data to be written to.</param>
-    /// <param name="saveDataId">The save data ID of the save data to be written to.</param>
-    /// <param name="extraData">The <see cref="SaveDataExtraData"/> to write to the save data.</param>
-    /// <param name="extraDataMask">A mask specifying which bits of <paramref name="extraData"/>
-    /// to write to the save's extra data. 0 = don't write, 1 = write.</param>
-    /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
-    /// <see cref="ResultFs.TargetNotFound"/>: The save data was not found.<br/>
-    /// <see cref="ResultFs.PermissionDenied"/>: Insufficient permissions.</returns>
-    /// <remarks>
-    /// Calling programs may have permission to write to all, some or none of the save data's extra data.
-    /// If any bits are set in <paramref name="extraDataMask"/> that the caller does not have the permissions
-    /// to write to, nothing will be written and <see cref="ResultFs.PermissionDenied"/> will be returned.
-    /// </remarks>
-    public static Result WriteSaveDataFileSystemExtraData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId,
-        ulong saveDataId, in SaveDataExtraData extraData, in SaveDataExtraData extraDataMask)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.WriteSaveDataFileSystemExtraDataWithMask(saveDataId, spaceId,
-            InBuffer.FromStruct(in extraData), InBuffer.FromStruct(in extraDataMask));
-        fs.AbortIfNeeded(rc);
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    /// <summary>
-    /// Writes the provided <paramref name="extraData"/> to the save data in the specified
-    /// <see cref="SaveDataSpaceId"/> that matches the provided <see cref="SaveDataAttribute"/> key.
-    /// The mask specifies which parts of the extra data will be written to the save data.
-    /// </summary>
-    /// <param name="fs">The <see cref="FileSystemClient"/> to use.</param>
-    /// <param name="spaceId">The <see cref="SaveDataSpaceId"/> containing the save data to be written to.</param>
-    /// <param name="attribute">The key for the save data.</param>
-    /// <param name="extraData">The <see cref="SaveDataExtraData"/> to write to the save data.</param>
-    /// <param name="extraDataMask">A mask specifying which bits of <paramref name="extraData"/>
-    /// to write to the save's extra data. 0 = don't write, 1 = write.</param>
-    /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
-    /// <see cref="ResultFs.TargetNotFound"/>: The save data was not found.<br/>
-    /// <see cref="ResultFs.PermissionDenied"/>: Insufficient permissions.</returns>
-    /// <remarks>
-    /// If <see cref="SaveDataAttribute.ProgramId"/> is set to <see cref="Fs.SaveData.AutoResolveCallerProgramId"/>,
-    /// the program ID of <paramref name="attribute"/> will be resolved to the default save data program ID of the calling program.<br/>
-    /// Calling programs may have permission to write to all, some or none of the save data's extra data.
-    /// If any bits are set in <paramref name="extraDataMask"/> that the caller does not have the permissions
-    /// to write to, nothing will be written and <see cref="ResultFs.PermissionDenied"/> will be returned.
-    /// </remarks>
-    public static Result WriteSaveDataFileSystemExtraData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId,
-        in SaveDataAttribute attribute, in SaveDataExtraData extraData, in SaveDataExtraData extraDataMask)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.WriteSaveDataFileSystemExtraDataWithMaskBySaveDataAttribute(in attribute,
-            spaceId, InBuffer.FromStruct(in extraData), InBuffer.FromStruct(in extraDataMask));
-        fs.AbortIfNeeded(rc);
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    public static Result FindSaveDataWithFilter(this FileSystemClientImpl fs, out SaveDataInfo saveInfo,
-        SaveDataSpaceId spaceId, in SaveDataFilter filter)
-    {
-        UnsafeHelpers.SkipParamInit(out saveInfo);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Unsafe.SkipInit(out SaveDataInfo tempInfo);
-        OutBuffer saveInfoBuffer = OutBuffer.FromStruct(ref tempInfo);
-
-        Result rc = fileSystemProxy.Get.FindSaveDataWithFilter(out long count, saveInfoBuffer, spaceId, in filter);
-        if (rc.IsFailure()) return rc;
-
-        if (count == 0)
-            return ResultFs.TargetNotFound.Log();
-
-        saveInfo = tempInfo;
-        return Result.Success;
-    }
-
-    public static Result CreateSaveData(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
-        UserId userId, ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Account,
-            userId, 0);
-        if (rc.IsFailure()) return rc;
-
-        rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
-            SaveDataSpaceId.User);
-        if (rc.IsFailure()) return rc;
-
-        var metaPolicy = new SaveDataMetaPolicy(SaveDataType.Account);
-        metaPolicy.GenerateMetaInfo(out SaveDataMetaInfo metaInfo);
-
-        rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    public static Result CreateBcatSaveData(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
-        long size)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Bcat,
-            Fs.SaveData.InvalidUserId, 0);
-        if (rc.IsFailure()) return rc;
-
-        rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size,
-            SaveDataProperties.BcatSaveDataJournalSize, SystemProgramId.Bcat.Value, SaveDataFlags.None,
-            SaveDataSpaceId.User);
-        if (rc.IsFailure()) return rc;
-
-        var metaInfo = new SaveDataMetaInfo
+        private class CacheStorageListCache : IDisposable
         {
-            Type = SaveDataMetaType.None,
-            Size = 0
-        };
+            public readonly struct CacheEntry
+            {
+                private readonly int _index;
 
-        rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
-        if (rc.IsFailure()) return rc.Miss();
+                public CacheEntry(int index) => _index = index;
+                public int GetCacheStorageIndex() => _index;
+            }
 
-        return Result.Success;
-    }
+            private int _position;
+            private List<CacheEntry> _entryList;
 
-    public static Result CreateDeviceSaveData(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
-        ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+            public CacheStorageListCache()
+            {
+                _position = 0;
+                _entryList = new List<CacheEntry>();
+            }
 
-        Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Device,
-            Fs.SaveData.InvalidUserId, 0);
-        if (rc.IsFailure()) return rc;
+            public void Dispose() { }
 
-        rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
-            SaveDataSpaceId.User);
-        if (rc.IsFailure()) return rc;
+            public Result PushBack(in CacheEntry entry)
+            {
+                _entryList.Add(entry);
 
-        var metaPolicy = new SaveDataMetaPolicy(SaveDataType.Device);
-        metaPolicy.GenerateMetaInfo(out SaveDataMetaInfo metaInfo);
+                // The original code can have allocation failures here
+                return Result.Success;
+            }
 
-        rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
-        if (rc.IsFailure()) return rc.Miss();
+            public ref readonly CacheEntry PopFront()
+            {
+                if (_position >= _entryList.Count)
+                    return ref Unsafe.NullRef<CacheEntry>();
 
-        return Result.Success;
-    }
+                return ref CollectionsMarshal.AsSpan(_entryList)[_position++];
+            }
 
-    public static Result CreateCacheStorage(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
-        SaveDataSpaceId spaceId, ulong ownerId, ushort index, long size, long journalSize, SaveDataFlags flags)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Cache,
-            Fs.SaveData.InvalidUserId, 0, index);
-        if (rc.IsFailure()) return rc;
-
-        rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
-            spaceId);
-        if (rc.IsFailure()) return rc;
-
-        var metaInfo = new SaveDataMetaInfo
-        {
-            Type = SaveDataMetaType.None,
-            Size = 0
-        };
-
-        rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    public static Result CreateSaveData(this FileSystemClientImpl fs, in SaveDataAttribute attribute,
-        in SaveDataCreationInfo creationInfo, in SaveDataMetaInfo metaInfo, in HashSalt hashSalt)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-        return fileSystemProxy.Get.CreateSaveDataFileSystemWithHashSalt(in attribute, in creationInfo,
-            in metaInfo, in hashSalt);
-    }
-
-    public static Result DeleteSaveData(this FileSystemClientImpl fs, ulong saveDataId)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-        return fileSystemProxy.Get.DeleteSaveDataFileSystem(saveDataId);
-    }
-
-    public static Result DeleteSaveData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-        return fileSystemProxy.Get.DeleteSaveDataFileSystemBySaveDataSpaceId(spaceId, saveDataId);
-    }
-
-    public static Result DeleteSaveData(this FileSystemClient fs, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x30];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.DeleteSaveData(saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.DeleteSaveData(saveDataId);
+            public static CacheStorageListCache GetCacheStorageListCache(CacheStorageListHandle handle)
+            {
+                return (CacheStorageListCache)handle.Cache;
+            }
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result DeleteSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
+            out SaveDataExtraData extraData, ulong saveDataId)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.DeleteSaveData(spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            UnsafeHelpers.SkipParamInit(out extraData);
 
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.DeleteSaveData(spaceId, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result DeleteSystemSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
-        UserId userId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x80];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = Delete(fs, spaceId, saveDataId, userId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = Delete(fs, spaceId, saveDataId, userId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result Delete(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, UserId userId)
-        {
-            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
-                SaveDataType.System, userId, saveDataId);
+            Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraData(OutBuffer.FromStruct(ref extraData), saveDataId);
             if (rc.IsFailure()) return rc;
 
-            return fileSystemProxy.Get.DeleteSaveDataFileSystemBySaveDataAttribute(spaceId, in attribute);
-        }
-    }
-
-    public static Result DeleteDeviceSaveData(this FileSystemClient fs, ApplicationId applicationId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x30];
-
-        if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = Delete(fs, applicationId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = Delete(fs, applicationId);
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result Delete(FileSystemClient fs, ApplicationId applicationId)
+        public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
+            out SaveDataExtraData extraData, SaveDataSpaceId spaceId, ulong saveDataId)
         {
-            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+            UnsafeHelpers.SkipParamInit(out extraData);
 
-            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, new ProgramId(applicationId.Value),
-                SaveDataType.Device, Fs.SaveData.InvalidUserId, 0);
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraDataBySaveDataSpaceId(
+                OutBuffer.FromStruct(ref extraData), spaceId, saveDataId);
             if (rc.IsFailure()) return rc;
 
-            return fileSystemProxy.Get.DeleteSaveDataFileSystemBySaveDataAttribute(SaveDataSpaceId.User, in attribute);
-        }
-    }
-
-    public static Result RegisterSaveDataAtomicDeletion(this FileSystemClient fs,
-        ReadOnlySpan<ulong> saveDataIdList)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.RegisterSaveDataFileSystemAtomicDeletion(InBuffer.FromSpan(saveDataIdList));
-        fs.Impl.AbortIfNeeded(rc);
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    public static Result OpenSaveDataIterator(this FileSystemClientImpl fs,
-        ref UniqueRef<SaveDataIterator> outIterator, SaveDataSpaceId spaceId)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-        using var reader = new SharedRef<ISaveDataInfoReader>();
-
-        Result rc = fileSystemProxy.Get.OpenSaveDataInfoReaderBySaveDataSpaceId(ref reader.Ref(), spaceId);
-        if (rc.IsFailure()) return rc;
-
-        using var iterator = new UniqueRef<SaveDataIterator>(new SaveDataIterator(fs.Fs, ref reader.Ref()));
-
-        if (!iterator.HasValue)
-            return ResultFs.AllocationMemoryFailedInSaveDataManagementA.Log();
-
-        outIterator.Set(ref iterator.Ref());
-
-        return Result.Success;
-    }
-
-    public static Result OpenSaveDataIterator(this FileSystemClientImpl fs,
-        ref UniqueRef<SaveDataIterator> outIterator, SaveDataSpaceId spaceId, in SaveDataFilter filter)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-        using var reader = new SharedRef<ISaveDataInfoReader>();
-
-        Result rc = fileSystemProxy.Get.OpenSaveDataInfoReaderWithFilter(ref reader.Ref(), spaceId, in filter);
-        if (rc.IsFailure()) return rc;
-
-        using var iterator = new UniqueRef<SaveDataIterator>(new SaveDataIterator(fs.Fs, ref reader.Ref()));
-
-        if (!iterator.HasValue)
-            return ResultFs.AllocationMemoryFailedInSaveDataManagementA.Log();
-
-        outIterator.Set(ref iterator.Ref());
-
-        return Result.Success;
-    }
-
-    public static Result ReadSaveDataIteratorSaveDataInfo(out long readCount, Span<SaveDataInfo> buffer,
-        in SaveDataIterator iterator)
-    {
-        Result rc = iterator.ReadSaveDataInfo(out readCount, buffer);
-        if (rc.IsFailure()) return rc.Miss();
-
-        return Result.Success;
-    }
-
-    public static Result OpenSaveDataIterator(this FileSystemClient fs, ref UniqueRef<SaveDataIterator> outIterator,
-        SaveDataSpaceId spaceId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId));
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId);
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result OpenSaveDataIterator(this FileSystemClient fs, ref UniqueRef<SaveDataIterator> outIterator,
-        SaveDataSpaceId spaceId, in SaveDataFilter filter)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
+            out SaveDataExtraData extraData, SaveDataSpaceId spaceId, in SaveDataAttribute attribute)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId, in filter);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            UnsafeHelpers.SkipParamInit(out extraData);
 
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId));
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId, in filter);
+            Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraDataBySaveDataAttribute(
+                OutBuffer.FromStruct(ref extraData), spaceId, in attribute);
+            if (rc.IsFailure()) return rc;
+
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result FindSaveDataWithFilter(this FileSystemClient fs, out SaveDataInfo info,
-        SaveDataSpaceId spaceId, in SaveDataFilter filter)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result ReadSaveDataFileSystemExtraData(this FileSystemClientImpl fs,
+            out SaveDataExtraData extraData, SaveDataSpaceId spaceId, in SaveDataAttribute attribute,
+            in SaveDataExtraData extraDataMask)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.FindSaveDataWithFilter(out info, spaceId, in filter);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            UnsafeHelpers.SkipParamInit(out extraData);
 
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId));
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.FindSaveDataWithFilter(out info, spaceId, in filter);
+            Result rc = fileSystemProxy.Get.ReadSaveDataFileSystemExtraDataWithMaskBySaveDataAttribute(
+                OutBuffer.FromStruct(ref extraData), spaceId, in attribute, InBuffer.FromStruct(in extraDataMask));
+            if (rc.IsFailure()) return rc;
+
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result CreateSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId, UserId userId,
-        ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x100];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        /// <summary>
+        /// Writes the <see cref="SaveDataExtraData.Flags"/> of the provided <see cref="SaveDataExtraData"/>
+        /// to the save data in the specified <see cref="SaveDataSpaceId"/> with the provided save data ID.
+        /// </summary>
+        /// <param name="fs">The <see cref="FileSystemClient"/> to use.</param>
+        /// <param name="spaceId">The <see cref="SaveDataSpaceId"/> containing the save data to be written to.</param>
+        /// <param name="saveDataId">The save data ID of the save data to be written to.</param>
+        /// <param name="extraData">The <see cref="SaveDataExtraData"/> containing the data to write.</param>
+        /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
+        /// <see cref="ResultFs.TargetNotFound"/>: The save data was not found.<br/>
+        /// <see cref="ResultFs.PermissionDenied"/>: Insufficient permissions.</returns>
+        public static Result WriteSaveDataFileSystemExtraData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId,
+            ulong saveDataId, in SaveDataExtraData extraData)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.CreateSaveData(applicationId, userId, ownerId, size, journalSize, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
-                .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
-                .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(size, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+            Result rc = fileSystemProxy.Get.WriteSaveDataFileSystemExtraData(saveDataId, spaceId,
+                InBuffer.FromStruct(in extraData));
+            fs.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc.Miss();
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.CreateSaveData(applicationId, userId, ownerId, size, journalSize, flags);
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result CreateSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId, UserId userId,
-        ulong ownerId, long size, long journalSize, in HashSalt hashSalt, SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x100];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        /// <summary>
+        /// Writes the provided <paramref name="extraData"/> to the save data in the specified
+        /// <see cref="SaveDataSpaceId"/> with the provided save data ID.
+        /// </summary>
+        /// <param name="fs">The <see cref="FileSystemClient"/> to use.</param>
+        /// <param name="spaceId">The <see cref="SaveDataSpaceId"/> containing the save data to be written to.</param>
+        /// <param name="saveDataId">The save data ID of the save data to be written to.</param>
+        /// <param name="extraData">The <see cref="SaveDataExtraData"/> to write to the save data.</param>
+        /// <param name="extraDataMask">A mask specifying which bits of <paramref name="extraData"/>
+        /// to write to the save's extra data. 0 = don't write, 1 = write.</param>
+        /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
+        /// <see cref="ResultFs.TargetNotFound"/>: The save data was not found.<br/>
+        /// <see cref="ResultFs.PermissionDenied"/>: Insufficient permissions.</returns>
+        /// <remarks>
+        /// Calling programs may have permission to write to all, some or none of the save data's extra data.
+        /// If any bits are set in <paramref name="extraDataMask"/> that the caller does not have the permissions
+        /// to write to, nothing will be written and <see cref="ResultFs.PermissionDenied"/> will be returned.
+        /// </remarks>
+        public static Result WriteSaveDataFileSystemExtraData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId,
+            ulong saveDataId, in SaveDataExtraData extraData, in SaveDataExtraData extraDataMask)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = CreateSave(fs, applicationId, userId, ownerId, size, journalSize, in hashSalt, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
-                .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
-                .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(size, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+            Result rc = fileSystemProxy.Get.WriteSaveDataFileSystemExtraDataWithMask(saveDataId, spaceId,
+                InBuffer.FromStruct(in extraData), InBuffer.FromStruct(in extraDataMask));
+            fs.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc.Miss();
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = CreateSave(fs, applicationId, userId, ownerId, size, journalSize, in hashSalt, flags);
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result CreateSave(FileSystemClient fs, Ncm.ApplicationId applicationId, UserId userId,
-            ulong ownerId, long size, long journalSize, in HashSalt hashSalt, SaveDataFlags flags)
+        /// <summary>
+        /// Writes the provided <paramref name="extraData"/> to the save data in the specified
+        /// <see cref="SaveDataSpaceId"/> that matches the provided <see cref="SaveDataAttribute"/> key.
+        /// The mask specifies which parts of the extra data will be written to the save data.
+        /// </summary>
+        /// <param name="fs">The <see cref="FileSystemClient"/> to use.</param>
+        /// <param name="spaceId">The <see cref="SaveDataSpaceId"/> containing the save data to be written to.</param>
+        /// <param name="attribute">The key for the save data.</param>
+        /// <param name="extraData">The <see cref="SaveDataExtraData"/> to write to the save data.</param>
+        /// <param name="extraDataMask">A mask specifying which bits of <paramref name="extraData"/>
+        /// to write to the save's extra data. 0 = don't write, 1 = write.</param>
+        /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
+        /// <see cref="ResultFs.TargetNotFound"/>: The save data was not found.<br/>
+        /// <see cref="ResultFs.PermissionDenied"/>: Insufficient permissions.</returns>
+        /// <remarks>
+        /// If <see cref="SaveDataAttribute.ProgramId"/> is set to <see cref="Fs.SaveData.AutoResolveCallerProgramId"/>,
+        /// the program ID of <paramref name="attribute"/> will be resolved to the default save data program ID of the calling program.<br/>
+        /// Calling programs may have permission to write to all, some or none of the save data's extra data.
+        /// If any bits are set in <paramref name="extraDataMask"/> that the caller does not have the permissions
+        /// to write to, nothing will be written and <see cref="ResultFs.PermissionDenied"/> will be returned.
+        /// </remarks>
+        public static Result WriteSaveDataFileSystemExtraData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId,
+            in SaveDataAttribute attribute, in SaveDataExtraData extraData, in SaveDataExtraData extraDataMask)
         {
-            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.WriteSaveDataFileSystemExtraDataWithMaskBySaveDataAttribute(in attribute,
+                spaceId, InBuffer.FromStruct(in extraData), InBuffer.FromStruct(in extraDataMask));
+            fs.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc.Miss();
+
+            return Result.Success;
+        }
+
+        public static Result FindSaveDataWithFilter(this FileSystemClientImpl fs, out SaveDataInfo saveInfo,
+            SaveDataSpaceId spaceId, in SaveDataFilter filter)
+        {
+            UnsafeHelpers.SkipParamInit(out saveInfo);
+
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            Unsafe.SkipInit(out SaveDataInfo tempInfo);
+            OutBuffer saveInfoBuffer = OutBuffer.FromStruct(ref tempInfo);
+
+            Result rc = fileSystemProxy.Get.FindSaveDataWithFilter(out long count, saveInfoBuffer, spaceId, in filter);
+            if (rc.IsFailure()) return rc;
+
+            if (count == 0)
+                return ResultFs.TargetNotFound.Log();
+
+            saveInfo = tempInfo;
+            return Result.Success;
+        }
+
+        public static Result CreateSaveData(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
+            UserId userId, ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
             Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Account,
-                userId, 0);
+                userId, staticSaveDataId: 0);
             if (rc.IsFailure()) return rc;
 
             rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
@@ -697,1349 +307,1950 @@ public static class SaveDataManagement
             var metaPolicy = new SaveDataMetaPolicy(SaveDataType.Account);
             metaPolicy.GenerateMetaInfo(out SaveDataMetaInfo metaInfo);
 
-            return fileSystemProxy.Get.CreateSaveDataFileSystemWithHashSalt(in attribute, in creationInfo, in metaInfo,
-                in hashSalt);
-        }
-    }
+            rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
+            if (rc.IsFailure()) return rc.Miss();
 
-    public static Result CreateBcatSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId, long size)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.CreateBcatSaveData(applicationId, size);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
-                .Append(LogSaveDataSize).AppendFormat(size, 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.CreateBcatSaveData(applicationId, size);
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result CreateDeviceSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId,
-        ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x100];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result CreateBcatSaveData(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
+            long size)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.CreateDeviceSaveData(applicationId, ownerId, size, journalSize, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
-                .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(size, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Bcat,
+                Fs.SaveData.InvalidUserId, staticSaveDataId: 0);
+            if (rc.IsFailure()) return rc;
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.CreateDeviceSaveData(applicationId, ownerId, size, journalSize, flags);
+            rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size,
+                SaveDataProperties.BcatSaveDataJournalSize, SystemProgramId.Bcat.Value, SaveDataFlags.None,
+                SaveDataSpaceId.User);
+            if (rc.IsFailure()) return rc;
+
+            var metaInfo = new SaveDataMetaInfo
+            {
+                Type = SaveDataMetaType.None,
+                Size = 0
+            };
+
+            rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
+            if (rc.IsFailure()) return rc.Miss();
+
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result CreateTemporaryStorage(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
-        ulong ownerId, long size, SaveDataFlags flags)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Temporary,
-            Fs.SaveData.InvalidUserId, 0);
-        if (rc.IsFailure()) return rc;
-
-        rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, 0, ownerId, flags,
-            SaveDataSpaceId.Temporary);
-        if (rc.IsFailure()) return rc;
-
-        var metaInfo = new SaveDataMetaInfo
-        {
-            Type = SaveDataMetaType.None,
-            Size = 0
-        };
-
-        return fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
-    }
-
-    public static Result CreateTemporaryStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
-        ulong ownerId, long size, SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x100];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.CreateTemporaryStorage(applicationId, ownerId, size, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
-                .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(size, 'd')
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.CreateTemporaryStorage(applicationId, ownerId, size, flags);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result CreateCacheStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
-        SaveDataSpaceId spaceId, ulong ownerId, ushort index, long size, long journalSize, SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x100];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.CreateCacheStorage(applicationId, spaceId, ownerId, index, size, journalSize, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
-                .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(size, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.CreateCacheStorage(applicationId, spaceId, ownerId, index, size, journalSize, flags);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result CreateCacheStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
-        SaveDataSpaceId spaceId, ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        return CreateCacheStorage(fs, applicationId, spaceId, ownerId, 0, size, journalSize, flags);
-    }
-
-    public static Result CreateCacheStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
-        ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        return CreateCacheStorage(fs, applicationId, SaveDataSpaceId.User, ownerId, size, journalSize, flags);
-    }
-
-    public static Result CreateSystemSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId,
-        ulong saveDataId, UserId userId, ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x100];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = CreateSave(fs, spaceId, saveDataId, userId, ownerId, size, journalSize, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
-                .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(size, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = CreateSave(fs, spaceId, saveDataId, userId, ownerId, size, journalSize, flags);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result CreateSave(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, UserId userId,
+        public static Result CreateDeviceSaveData(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
             ulong ownerId, long size, long journalSize, SaveDataFlags flags)
         {
-            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
 
-            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
-                SaveDataType.System, userId, saveDataId);
+            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Device,
+                Fs.SaveData.InvalidUserId, staticSaveDataId: 0);
+            if (rc.IsFailure()) return rc;
+
+            rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
+                SaveDataSpaceId.User);
+            if (rc.IsFailure()) return rc;
+
+            var metaPolicy = new SaveDataMetaPolicy(SaveDataType.Device);
+            metaPolicy.GenerateMetaInfo(out SaveDataMetaInfo metaInfo);
+
+            rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
+            if (rc.IsFailure()) return rc.Miss();
+
+            return Result.Success;
+        }
+
+        public static Result CreateCacheStorage(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
+            SaveDataSpaceId spaceId, ulong ownerId, ushort index, long size, long journalSize, SaveDataFlags flags)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Cache,
+                Fs.SaveData.InvalidUserId, staticSaveDataId: 0, index);
             if (rc.IsFailure()) return rc;
 
             rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
                 spaceId);
             if (rc.IsFailure()) return rc;
 
-            return fileSystemProxy.Get.CreateSaveDataFileSystemBySystemSaveDataId(in attribute, in creationInfo);
-        }
-    }
+            var metaInfo = new SaveDataMetaInfo
+            {
+                Type = SaveDataMetaType.None,
+                Size = 0
+            };
 
-    public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, UserId userId,
-        ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        return CreateSystemSaveData(fs, SaveDataSpaceId.System, saveDataId, userId, ownerId, size, journalSize,
-            flags);
-    }
+            rc = fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
+            if (rc.IsFailure()) return rc.Miss();
 
-    public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, UserId userId, long size,
-        long journalSize, SaveDataFlags flags)
-    {
-        return CreateSystemSaveData(fs, saveDataId, userId, 0, size, journalSize, flags);
-    }
-
-    public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, ulong ownerId, long size,
-        long journalSize, SaveDataFlags flags)
-    {
-        return CreateSystemSaveData(fs, saveDataId, Fs.SaveData.InvalidUserId, ownerId, size, journalSize, flags);
-    }
-
-    public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, long size,
-        long journalSize, SaveDataFlags flags)
-    {
-        return CreateSystemSaveData(fs, saveDataId, Fs.SaveData.InvalidUserId, 0, size, journalSize, flags);
-    }
-
-    public static Result CreateSystemSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
-        ulong ownerId, long size, long journalSize, SaveDataFlags flags)
-    {
-        return CreateSystemSaveData(fs, spaceId, saveDataId, Fs.SaveData.InvalidUserId, ownerId, size, journalSize,
-            flags);
-    }
-
-    public static Result ExtendSaveData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId, ulong saveDataId,
-        long saveDataSize, long journalSize)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        return fileSystemProxy.Get.ExtendSaveDataFileSystem(spaceId, saveDataId, saveDataSize, journalSize);
-    }
-
-    public static Result ExtendSaveData(this FileSystemClient fs, ulong saveDataId, long saveDataSize,
-        long journalSize)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x90];
-
-        var spaceId = SaveDataSpaceId.System;
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(saveDataSize, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result ExtendSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
-        long saveDataSize, long journalSize)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x90];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogSaveDataSize).AppendFormat(saveDataSize, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result QuerySaveDataTotalSize(this FileSystemClientImpl fs, out long totalSize, long size,
-        long journalSize)
-    {
-        UnsafeHelpers.SkipParamInit(out totalSize);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.QuerySaveDataTotalSize(out long tempTotalSize, size, journalSize);
-        if (rc.IsFailure()) return rc.Miss();
-
-        totalSize = tempTotalSize;
-        return Result.Success;
-    }
-
-    public static Result QuerySaveDataTotalSize(this FileSystemClient fs, out long totalSize, long size,
-        long journalSize)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.QuerySaveDataTotalSize(out totalSize, size, journalSize);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataSize).AppendFormat(size, 'd')
-                .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.QuerySaveDataTotalSize(out totalSize, size, journalSize);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result GetSaveDataOwnerId(this FileSystemClient fs, out ulong ownerId, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x40];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetOwnerId(fs, out ownerId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            // Note: Nintendo accidentally uses ", save_data_size: %ld" instead of ", savedataid: 0x%lX"
-            // for the format string.
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetOwnerId(fs, out ownerId, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetOwnerId(FileSystemClient fs, out ulong ownerId, ulong saveDataId)
-        {
-            UnsafeHelpers.SkipParamInit(out ownerId);
-
-            Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
-            if (rc.IsFailure()) return rc;
-
-            ownerId = extraData.OwnerId;
             return Result.Success;
         }
-    }
 
-    public static Result GetSaveDataOwnerId(this FileSystemClient fs, out ulong ownerId, SaveDataSpaceId spaceId,
-        ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result CreateSaveData(this FileSystemClientImpl fs, in SaveDataAttribute attribute,
+            in SaveDataCreationInfo creationInfo, in SaveDataMetaInfo metaInfo, in HashSalt hashSalt)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetOwnerId(fs, out ownerId, spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetOwnerId(fs, out ownerId, spaceId, saveDataId);
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+            return fileSystemProxy.Get.CreateSaveDataFileSystemWithHashSalt(in attribute, in creationInfo,
+                in metaInfo, in hashSalt);
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetOwnerId(FileSystemClient fs, out ulong ownerId, SaveDataSpaceId spaceId, ulong saveDataId)
+        public static Result DeleteSaveData(this FileSystemClientImpl fs, ulong saveDataId)
         {
-            UnsafeHelpers.SkipParamInit(out ownerId);
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+            return fileSystemProxy.Get.DeleteSaveDataFileSystem(saveDataId);
+        }
 
-            Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
-                saveDataId);
-            if (rc.IsFailure()) return rc;
+        public static Result DeleteSaveData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+            return fileSystemProxy.Get.DeleteSaveDataFileSystemBySaveDataSpaceId(spaceId, saveDataId);
+        }
+
+        public static Result DeleteSaveData(this FileSystemClient fs, ulong saveDataId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x30];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.DeleteSaveData(saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.DeleteSaveData(saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result DeleteSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.DeleteSaveData(spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.DeleteSaveData(spaceId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result DeleteSystemSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
+            UserId userId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x80];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = Delete(fs, spaceId, saveDataId, userId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = Delete(fs, spaceId, saveDataId, userId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result Delete(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, UserId userId)
+            {
+                using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+                Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
+                    SaveDataType.System, userId, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                return fileSystemProxy.Get.DeleteSaveDataFileSystemBySaveDataAttribute(spaceId, in attribute);
+            }
+        }
+
+        public static Result DeleteDeviceSaveData(this FileSystemClient fs, ApplicationId applicationId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x30];
+
+            if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = Delete(fs, applicationId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = Delete(fs, applicationId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result Delete(FileSystemClient fs, ApplicationId applicationId)
+            {
+                using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+                Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, new ProgramId(applicationId.Value),
+                    SaveDataType.Device, Fs.SaveData.InvalidUserId, staticSaveDataId: 0);
+                if (rc.IsFailure()) return rc;
+
+                return fileSystemProxy.Get.DeleteSaveDataFileSystemBySaveDataAttribute(SaveDataSpaceId.User, in attribute);
+            }
+        }
+
+        public static Result RegisterSaveDataAtomicDeletion(this FileSystemClient fs,
+            ReadOnlySpan<ulong> saveDataIdList)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.RegisterSaveDataFileSystemAtomicDeletion(InBuffer.FromSpan(saveDataIdList));
+            fs.Impl.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc.Miss();
 
-            ownerId = extraData.OwnerId;
             return Result.Success;
         }
-    }
 
-    public static Result GetSaveDataFlags(this FileSystemClient fs, out SaveDataFlags flags, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x40];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result OpenSaveDataIterator(this FileSystemClientImpl fs,
+            ref UniqueRef<SaveDataIterator> outIterator, SaveDataSpaceId spaceId)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetFlags(fs, out flags, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+            using var reader = new SharedRef<ISaveDataInfoReader>();
 
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetFlags(fs, out flags, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetFlags(FileSystemClient fs, out SaveDataFlags flags, ulong saveDataId)
-        {
-            UnsafeHelpers.SkipParamInit(out flags);
-
-            Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
+            Result rc = fileSystemProxy.Get.OpenSaveDataInfoReaderBySaveDataSpaceId(ref reader.Ref(), spaceId);
             if (rc.IsFailure()) return rc;
 
-            flags = extraData.Flags;
+            using var iterator = new UniqueRef<SaveDataIterator>(new SaveDataIterator(fs.Fs, ref reader.Ref()));
+
+            if (!iterator.HasValue)
+                return ResultFs.AllocationMemoryFailedInSaveDataManagementA.Log();
+
+            outIterator.Set(ref iterator.Ref());
+
             return Result.Success;
         }
-    }
 
-    public static Result GetSaveDataFlags(this FileSystemClient fs, out SaveDataFlags flags,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result OpenSaveDataIterator(this FileSystemClientImpl fs,
+            ref UniqueRef<SaveDataIterator> outIterator, SaveDataSpaceId spaceId, in SaveDataFilter filter)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetFlags(fs, out flags, spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+            using var reader = new SharedRef<ISaveDataInfoReader>();
 
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
+            Result rc = fileSystemProxy.Get.OpenSaveDataInfoReaderWithFilter(ref reader.Ref(), spaceId, in filter);
+            if (rc.IsFailure()) return rc;
 
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+            using var iterator = new UniqueRef<SaveDataIterator>(new SaveDataIterator(fs.Fs, ref reader.Ref()));
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetFlags(fs, out flags, spaceId, saveDataId);
+            if (!iterator.HasValue)
+                return ResultFs.AllocationMemoryFailedInSaveDataManagementA.Log();
+
+            outIterator.Set(ref iterator.Ref());
+
+            return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
+        public static Result ReadSaveDataIteratorSaveDataInfo(this FileSystemClientImpl fs, out long readCount,
+            Span<SaveDataInfo> buffer, in SaveDataIterator iterator)
+        {
+            Result rc = iterator.ReadSaveDataInfo(out readCount, buffer);
+            if (rc.IsFailure()) return rc.Miss();
 
-        static Result GetFlags(FileSystemClient fs, out SaveDataFlags flags, SaveDataSpaceId spaceId,
+            return Result.Success;
+        }
+
+        public static Result OpenSaveDataIterator(this FileSystemClient fs, ref UniqueRef<SaveDataIterator> outIterator,
+            SaveDataSpaceId spaceId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId));
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result OpenSaveDataIterator(this FileSystemClient fs, ref UniqueRef<SaveDataIterator> outIterator,
+            SaveDataSpaceId spaceId, in SaveDataFilter filter)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId, in filter);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId));
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.OpenSaveDataIterator(ref outIterator, spaceId, in filter);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result FindSaveDataWithFilter(this FileSystemClient fs, out SaveDataInfo info,
+            SaveDataSpaceId spaceId, in SaveDataFilter filter)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.FindSaveDataWithFilter(out info, spaceId, in filter);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId));
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.FindSaveDataWithFilter(out info, spaceId, in filter);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result CreateSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId, UserId userId,
+            ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x100];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.CreateSaveData(applicationId, userId, ownerId, size, journalSize, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
+                    .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
+                    .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(size, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.CreateSaveData(applicationId, userId, ownerId, size, journalSize, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result CreateSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId, UserId userId,
+            ulong ownerId, long size, long journalSize, in HashSalt hashSalt, SaveDataFlags flags)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x100];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = CreateSave(fs, applicationId, userId, ownerId, size, journalSize, in hashSalt, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
+                    .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
+                    .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(size, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = CreateSave(fs, applicationId, userId, ownerId, size, journalSize, in hashSalt, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result CreateSave(FileSystemClient fs, Ncm.ApplicationId applicationId, UserId userId,
+                ulong ownerId, long size, long journalSize, in HashSalt hashSalt, SaveDataFlags flags)
+            {
+                using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+                Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Account,
+                    userId, staticSaveDataId: 0);
+                if (rc.IsFailure()) return rc;
+
+                rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
+                    SaveDataSpaceId.User);
+                if (rc.IsFailure()) return rc;
+
+                var metaPolicy = new SaveDataMetaPolicy(SaveDataType.Account);
+                metaPolicy.GenerateMetaInfo(out SaveDataMetaInfo metaInfo);
+
+                return fileSystemProxy.Get.CreateSaveDataFileSystemWithHashSalt(in attribute, in creationInfo, in metaInfo,
+                    in hashSalt);
+            }
+        }
+
+        public static Result CreateBcatSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId, long size)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.CreateBcatSaveData(applicationId, size);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(size, 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.CreateBcatSaveData(applicationId, size);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result CreateDeviceSaveData(this FileSystemClient fs, Ncm.ApplicationId applicationId,
+            ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x100];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.CreateDeviceSaveData(applicationId, ownerId, size, journalSize, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
+                    .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(size, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.CreateDeviceSaveData(applicationId, ownerId, size, journalSize, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result CreateTemporaryStorage(this FileSystemClientImpl fs, Ncm.ApplicationId applicationId,
+            ulong ownerId, long size, SaveDataFlags flags)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, applicationId, SaveDataType.Temporary,
+                Fs.SaveData.InvalidUserId, staticSaveDataId: 0);
+            if (rc.IsFailure()) return rc;
+
+            rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize: 0, ownerId, flags,
+                SaveDataSpaceId.Temporary);
+            if (rc.IsFailure()) return rc;
+
+            var metaInfo = new SaveDataMetaInfo
+            {
+                Type = SaveDataMetaType.None,
+                Size = 0
+            };
+
+            return fileSystemProxy.Get.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
+        }
+
+        public static Result CreateTemporaryStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
+            ulong ownerId, long size, SaveDataFlags flags)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x100];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.CreateTemporaryStorage(applicationId, ownerId, size, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
+                    .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(size, 'd')
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.CreateTemporaryStorage(applicationId, ownerId, size, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result CreateCacheStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
+            SaveDataSpaceId spaceId, ulong ownerId, ushort index, long size, long journalSize, SaveDataFlags flags)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x100];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.CreateCacheStorage(applicationId, spaceId, ownerId, index, size, journalSize, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
+                    .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(size, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.CreateCacheStorage(applicationId, spaceId, ownerId, index, size, journalSize, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result CreateCacheStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
+            SaveDataSpaceId spaceId, ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            return CreateCacheStorage(fs, applicationId, spaceId, ownerId, index: 0, size, journalSize, flags);
+        }
+
+        public static Result CreateCacheStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
+            ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            return CreateCacheStorage(fs, applicationId, SaveDataSpaceId.User, ownerId, size, journalSize, flags);
+        }
+
+        public static Result CreateSystemSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId,
+            ulong saveDataId, UserId userId, ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x100];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = CreateSave(fs, spaceId, saveDataId, userId, ownerId, size, journalSize, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
+                    .Append(LogSaveDataOwnerId).AppendFormat(ownerId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(size, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd')
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = CreateSave(fs, spaceId, saveDataId, userId, ownerId, size, journalSize, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result CreateSave(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, UserId userId,
+                ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+            {
+                using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+                Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
+                    SaveDataType.System, userId, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                rc = SaveDataCreationInfo.Make(out SaveDataCreationInfo creationInfo, size, journalSize, ownerId, flags,
+                    spaceId);
+                if (rc.IsFailure()) return rc;
+
+                return fileSystemProxy.Get.CreateSaveDataFileSystemBySystemSaveDataId(in attribute, in creationInfo);
+            }
+        }
+
+        public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, UserId userId,
+            ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            return CreateSystemSaveData(fs, SaveDataSpaceId.System, saveDataId, userId, ownerId, size, journalSize,
+                flags);
+        }
+
+        public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, UserId userId, long size,
+            long journalSize, SaveDataFlags flags)
+        {
+            return CreateSystemSaveData(fs, saveDataId, userId, ownerId: 0, size, journalSize, flags);
+        }
+
+        public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, ulong ownerId, long size,
+            long journalSize, SaveDataFlags flags)
+        {
+            return CreateSystemSaveData(fs, saveDataId, Fs.SaveData.InvalidUserId, ownerId, size, journalSize, flags);
+        }
+
+        public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, long size,
+            long journalSize, SaveDataFlags flags)
+        {
+            return CreateSystemSaveData(fs, saveDataId, Fs.SaveData.InvalidUserId, ownerId: 0, size, journalSize, flags);
+        }
+
+        public static Result CreateSystemSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
+            ulong ownerId, long size, long journalSize, SaveDataFlags flags)
+        {
+            return CreateSystemSaveData(fs, spaceId, saveDataId, Fs.SaveData.InvalidUserId, ownerId, size, journalSize,
+                flags);
+        }
+
+        public static Result ExtendSaveData(this FileSystemClientImpl fs, SaveDataSpaceId spaceId, ulong saveDataId,
+            long saveDataSize, long journalSize)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            return fileSystemProxy.Get.ExtendSaveDataFileSystem(spaceId, saveDataId, saveDataSize, journalSize);
+        }
+
+        public static Result ExtendSaveData(this FileSystemClient fs, ulong saveDataId, long saveDataSize,
+            long journalSize)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x90];
+
+            var spaceId = SaveDataSpaceId.System;
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(saveDataSize, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result ExtendSaveData(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
+            long saveDataSize, long journalSize)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x90];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(saveDataSize, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(journalSize, 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.ExtendSaveData(spaceId, saveDataId, saveDataSize, journalSize);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result QuerySaveDataTotalSize(this FileSystemClientImpl fs, out long totalSize, long saveDataSize,
+            long saveDataJournalSize)
+        {
+            UnsafeHelpers.SkipParamInit(out totalSize);
+
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.QuerySaveDataTotalSize(out long tempTotalSize, saveDataSize,
+                saveDataJournalSize);
+            if (rc.IsFailure()) return rc.Miss();
+
+            totalSize = tempTotalSize;
+            return Result.Success;
+        }
+
+        public static Result QuerySaveDataTotalSize(this FileSystemClient fs, out long totalSize, long saveDataSize,
+            long saveDataJournalSize)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.QuerySaveDataTotalSize(out totalSize, saveDataSize, saveDataJournalSize);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataSize).AppendFormat(saveDataSize, 'd')
+                    .Append(LogSaveDataJournalSize).AppendFormat(saveDataJournalSize, 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.QuerySaveDataTotalSize(out totalSize, saveDataSize, saveDataJournalSize);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result GetSaveDataOwnerId(this FileSystemClient fs, out ulong ownerId, ulong saveDataId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x40];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetOwnerId(fs, out ownerId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                // Note: Nintendo accidentally uses ", save_data_size: %ld" instead of ", savedataid: 0x%lX"
+                // for the format string.
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetOwnerId(fs, out ownerId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetOwnerId(FileSystemClient fs, out ulong ownerId, ulong saveDataId)
+            {
+                UnsafeHelpers.SkipParamInit(out ownerId);
+
+                Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                ownerId = extraData.OwnerId;
+                return Result.Success;
+            }
+        }
+
+        public static Result GetSaveDataOwnerId(this FileSystemClient fs, out ulong ownerId, SaveDataSpaceId spaceId,
             ulong saveDataId)
         {
-            UnsafeHelpers.SkipParamInit(out flags);
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
 
-            Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
-                saveDataId);
-            if (rc.IsFailure()) return rc;
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetOwnerId(fs, out ownerId, spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            flags = extraData.Flags;
-            return Result.Success;
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetOwnerId(fs, out ownerId, spaceId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetOwnerId(FileSystemClient fs, out ulong ownerId, SaveDataSpaceId spaceId, ulong saveDataId)
+            {
+                UnsafeHelpers.SkipParamInit(out ownerId);
+
+                Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
+                    saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                ownerId = extraData.OwnerId;
+                return Result.Success;
+            }
         }
-    }
 
-    public static Result GetSystemSaveDataFlags(this FileSystemClient fs, out SaveDataFlags flags,
-        SaveDataSpaceId spaceId, ulong saveDataId, UserId userId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x80];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result GetSaveDataFlags(this FileSystemClient fs, out SaveDataFlags flags, ulong saveDataId)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetFlags(fs, out flags, spaceId, saveDataId, userId);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x40];
 
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetFlags(fs, out flags, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16);
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetFlags(fs, out flags, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetFlags(FileSystemClient fs, out SaveDataFlags flags, ulong saveDataId)
+            {
+                UnsafeHelpers.SkipParamInit(out flags);
+
+                Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                flags = extraData.Flags;
+                return Result.Success;
+            }
         }
-        else
+
+        public static Result GetSaveDataFlags(this FileSystemClient fs, out SaveDataFlags flags,
+            SaveDataSpaceId spaceId, ulong saveDataId)
         {
-            rc = GetFlags(fs, out flags, spaceId, saveDataId, userId);
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetFlags(fs, out flags, spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetFlags(fs, out flags, spaceId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetFlags(FileSystemClient fs, out SaveDataFlags flags, SaveDataSpaceId spaceId,
+                ulong saveDataId)
+            {
+                UnsafeHelpers.SkipParamInit(out flags);
+
+                Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
+                    saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                flags = extraData.Flags;
+                return Result.Success;
+            }
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetFlags(FileSystemClient fs, out SaveDataFlags flags, SaveDataSpaceId spaceId,
-            ulong saveDataId, UserId userId)
+        public static Result GetSystemSaveDataFlags(this FileSystemClient fs, out SaveDataFlags flags,
+            SaveDataSpaceId spaceId, ulong saveDataId, UserId userId)
         {
-            UnsafeHelpers.SkipParamInit(out flags);
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x80];
 
-            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
-                SaveDataType.System, userId, saveDataId);
-            if (rc.IsFailure()) return rc;
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetFlags(fs, out flags, spaceId, saveDataId, userId);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId, in attribute);
-            if (rc.IsFailure()) return rc;
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
 
-            flags = extraData.Flags;
-            return Result.Success;
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetFlags(fs, out flags, spaceId, saveDataId, userId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetFlags(FileSystemClient fs, out SaveDataFlags flags, SaveDataSpaceId spaceId,
+                ulong saveDataId, UserId userId)
+            {
+                UnsafeHelpers.SkipParamInit(out flags);
+
+                Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
+                    SaveDataType.System, userId, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId, in attribute);
+                if (rc.IsFailure()) return rc;
+
+                flags = extraData.Flags;
+                return Result.Success;
+            }
         }
-    }
 
-    public static Result SetSaveDataFlags(this FileSystemClient fs, ulong saveDataId, SaveDataFlags flags)
-    {
-        return SetSaveDataFlags(fs, saveDataId, SaveDataSpaceId.System, flags);
-    }
-
-    public static Result SetSaveDataFlags(this FileSystemClient fs, ulong saveDataId, SaveDataSpaceId spaceId,
-        SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x70];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result SetSaveDataFlags(this FileSystemClient fs, ulong saveDataId, SaveDataFlags flags)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = SetFlags(fs, saveDataId, spaceId, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = SetFlags(fs, saveDataId, spaceId, flags);
+            return SetSaveDataFlags(fs, saveDataId, SaveDataSpaceId.System, flags);
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result SetFlags(FileSystemClient fs, ulong saveDataId, SaveDataSpaceId spaceId, SaveDataFlags flags)
-        {
-            Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
-                saveDataId);
-            if (rc.IsFailure()) return rc;
-
-            extraData.Flags = flags;
-
-            return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, saveDataId, in extraData);
-        }
-    }
-
-    public static Result SetSystemSaveDataFlags(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
-        UserId userId, SaveDataFlags flags)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0xA0];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = SetFlags(fs, spaceId, saveDataId, userId, flags);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
-                .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = SetFlags(fs, spaceId, saveDataId, userId, flags);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result SetFlags(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, UserId userId,
+        public static Result SetSaveDataFlags(this FileSystemClient fs, ulong saveDataId, SaveDataSpaceId spaceId,
             SaveDataFlags flags)
         {
-            var extraDataMask = new SaveDataExtraData();
-            extraDataMask.Flags = unchecked((SaveDataFlags)0xFFFFFFFF);
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x70];
 
-            var extraData = new SaveDataExtraData();
-            extraData.Flags = flags;
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = SetFlags(fs, saveDataId, spaceId, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
-                SaveDataType.System, userId, saveDataId);
-            if (rc.IsFailure()) return rc;
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
 
-            return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, in attribute, in extraData, in extraDataMask);
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = SetFlags(fs, saveDataId, spaceId, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result SetFlags(FileSystemClient fs, ulong saveDataId, SaveDataSpaceId spaceId, SaveDataFlags flags)
+            {
+                Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
+                    saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                extraData.Flags = flags;
+
+                return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, saveDataId, in extraData);
+            }
         }
-    }
 
-    public static Result GetSaveDataTimeStamp(this FileSystemClient fs, out PosixTime timeStamp, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x30];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result SetSystemSaveDataFlags(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
+            UserId userId, SaveDataFlags flags)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetTimeStamp(fs, out timeStamp, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0xA0];
 
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = SetFlags(fs, spaceId, saveDataId, userId, flags);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogUserId).AppendFormat(userId.Id.High, 'X', 16).AppendFormat(userId.Id.Low, 'X', 16)
+                    .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataFlags).AppendFormat((int)flags, 'X', 8);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = SetFlags(fs, spaceId, saveDataId, userId, flags);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result SetFlags(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, UserId userId,
+                SaveDataFlags flags)
+            {
+                SaveDataExtraData extraDataMask = default;
+                extraDataMask.Flags = unchecked((SaveDataFlags)0xFFFFFFFF);
+
+                SaveDataExtraData extraData = default;
+                extraData.Flags = flags;
+
+                Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, Fs.SaveData.InvalidProgramId,
+                    SaveDataType.System, userId, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, in attribute, in extraData, in extraDataMask);
+            }
         }
-        else
+
+        public static Result GetSaveDataTimeStamp(this FileSystemClient fs, out PosixTime timeStamp, ulong saveDataId)
         {
-            rc = GetTimeStamp(fs, out timeStamp, saveDataId);
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x30];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetTimeStamp(fs, out timeStamp, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetTimeStamp(fs, out timeStamp, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetTimeStamp(FileSystemClient fs, out PosixTime timeStamp, ulong saveDataId)
+            {
+                UnsafeHelpers.SkipParamInit(out timeStamp);
+
+                Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                timeStamp = new PosixTime(extraData.TimeStamp);
+                return Result.Success;
+            }
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetTimeStamp(FileSystemClient fs, out PosixTime timeStamp, ulong saveDataId)
-        {
-            UnsafeHelpers.SkipParamInit(out timeStamp);
-
-            Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
-            if (rc.IsFailure()) return rc;
-
-            timeStamp = new PosixTime(extraData.TimeStamp);
-            return Result.Success;
-        }
-    }
-
-    public static Result SetSaveDataTimeStamp(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
-        PosixTime timeStamp)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x80];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = SetTimeStamp(fs, spaceId, saveDataId, timeStamp);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataTimeStamp).AppendFormat(timeStamp.Value, 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = SetTimeStamp(fs, spaceId, saveDataId, timeStamp);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result SetTimeStamp(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
+        public static Result SetSaveDataTimeStamp(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
             PosixTime timeStamp)
         {
-            var extraDataMask = new SaveDataExtraData();
-            extraDataMask.TimeStamp = unchecked((long)0xFFFFFFFFFFFFFFFF);
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x80];
 
-            var extraData = new SaveDataExtraData();
-            extraData.TimeStamp = timeStamp.Value;
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = SetTimeStamp(fs, spaceId, saveDataId, timeStamp);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, saveDataId, in extraData, in extraDataMask);
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataTimeStamp).AppendFormat(timeStamp.Value, 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = SetTimeStamp(fs, spaceId, saveDataId, timeStamp);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result SetTimeStamp(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
+                PosixTime timeStamp)
+            {
+                SaveDataExtraData extraDataMask = default;
+                extraDataMask.TimeStamp = unchecked((long)0xFFFFFFFFFFFFFFFF);
+
+                SaveDataExtraData extraData = default;
+                extraData.TimeStamp = timeStamp.Value;
+
+                return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, saveDataId, in extraData, in extraDataMask);
+            }
         }
-    }
 
-    public static Result GetSaveDataTimeStamp(this FileSystemClient fs, out PosixTime timeStamp,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result GetSaveDataTimeStamp(this FileSystemClient fs, out PosixTime timeStamp,
+            SaveDataSpaceId spaceId, ulong saveDataId)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetTimeStamp(fs, out timeStamp, spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
 
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetTimeStamp(fs, out timeStamp, spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetTimeStamp(fs, out timeStamp, spaceId, saveDataId);
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetTimeStamp(fs, out timeStamp, spaceId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetTimeStamp(FileSystemClient fs, out PosixTime timeStamp, SaveDataSpaceId spaceId,
+                ulong saveDataId)
+            {
+                UnsafeHelpers.SkipParamInit(out timeStamp);
+
+                Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
+                    saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                timeStamp = new PosixTime(extraData.TimeStamp);
+                return Result.Success;
+            }
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetTimeStamp(FileSystemClient fs, out PosixTime timeStamp, SaveDataSpaceId spaceId,
+        public static Result GetSaveDataAvailableSize(this FileSystemClientImpl fs, out long availableSize,
             ulong saveDataId)
         {
-            UnsafeHelpers.SkipParamInit(out timeStamp);
+            UnsafeHelpers.SkipParamInit(out availableSize);
 
-            Result rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId,
-                saveDataId);
+            Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
             if (rc.IsFailure()) return rc;
 
-            timeStamp = new PosixTime(extraData.TimeStamp);
-            return Result.Success;
-        }
-    }
-
-    public static Result GetSaveDataAvailableSize(this FileSystemClientImpl fs, out long availableSize,
-        ulong saveDataId)
-    {
-        UnsafeHelpers.SkipParamInit(out availableSize);
-
-        Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
-        if (rc.IsFailure()) return rc;
-
-        availableSize = extraData.DataSize;
-        return Result.Success;
-    }
-
-    public static Result GetSaveDataAvailableSize(this FileSystemClientImpl fs, out long availableSize,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        UnsafeHelpers.SkipParamInit(out availableSize);
-
-        Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId, saveDataId);
-        if (rc.IsFailure()) return rc;
-
-        availableSize = extraData.DataSize;
-        return Result.Success;
-    }
-
-    public static Result GetSaveDataAvailableSize(this FileSystemClient fs, out long availableSize,
-        ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x40];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result GetSaveDataAvailableSize(this FileSystemClient fs, out long availableSize,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, spaceId, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result GetSaveDataJournalSize(this FileSystemClientImpl fs, out long journalSize,
-        ulong saveDataId)
-    {
-        UnsafeHelpers.SkipParamInit(out journalSize);
-
-        Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
-        if (rc.IsFailure()) return rc;
-
-        journalSize = extraData.JournalSize;
-        return Result.Success;
-    }
-
-    public static Result GetSaveDataJournalSize(this FileSystemClientImpl fs, out long journalSize,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        UnsafeHelpers.SkipParamInit(out journalSize);
-
-        Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId, saveDataId);
-        if (rc.IsFailure()) return rc;
-
-        journalSize = extraData.JournalSize;
-        return Result.Success;
-    }
-
-    public static Result GetSaveDataJournalSize(this FileSystemClient fs, out long journalSize, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x40];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.GetSaveDataJournalSize(out journalSize, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.GetSaveDataJournalSize(out journalSize, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result GetSaveDataJournalSize(this FileSystemClient fs, out long journalSize,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.GetSaveDataJournalSize(out journalSize, spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.GetSaveDataJournalSize(out journalSize, spaceId, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result GetSaveDataCommitId(this FileSystemClient fs, out long commitId, SaveDataSpaceId spaceId,
-        ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetCommitId(fs, out commitId, spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetCommitId(fs, out commitId, spaceId, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetCommitId(FileSystemClient fs, out long commitId, SaveDataSpaceId spaceId, ulong saveDataId)
-        {
-            UnsafeHelpers.SkipParamInit(out commitId);
-
-            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-            return fileSystemProxy.Get.GetSaveDataCommitId(out commitId, spaceId, saveDataId);
-        }
-    }
-
-    public static Result SetSaveDataCommitId(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
-        long commitId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x80];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = SetCommitId(fs, spaceId, saveDataId, commitId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
-                .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataCommitId).AppendFormat(commitId, 'X', 16);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = SetCommitId(fs, spaceId, saveDataId, commitId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result SetCommitId(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, long commitId)
-        {
-            var extraDataMask = new SaveDataExtraData();
-            extraDataMask.CommitId = unchecked((long)0xFFFFFFFFFFFFFFFF);
-
-            var extraData = new SaveDataExtraData();
-            extraData.CommitId = commitId;
-
-            return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, saveDataId, in extraData, in extraDataMask);
-        }
-    }
-
-    public static Result QuerySaveDataInternalStorageTotalSize(this FileSystemClientImpl fs, out long size,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        UnsafeHelpers.SkipParamInit(out size);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
-
-        return fileSystemProxy.Get.QuerySaveDataInternalStorageTotalSize(out size, spaceId, saveDataId);
-    }
-
-    public static Result QuerySaveDataInternalStorageTotalSize(this FileSystemClient fs, out long size,
-        SaveDataSpaceId spaceId, ulong saveDataId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x50];
-
-        if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.QuerySaveDataInternalStorageTotalSize(out size, spaceId, saveDataId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var idString = new IdString();
-            var sb = new U8StringBuilder(logBuffer, true);
-
-            sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
-                .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.QuerySaveDataInternalStorageTotalSize(out size, spaceId, saveDataId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result VerifySaveData(this FileSystemClient fs, out bool isValid, ulong saveDataId,
-        Span<byte> workBuffer)
-    {
-        return VerifySaveData(fs, out isValid, SaveDataSpaceId.System, saveDataId, workBuffer);
-    }
-
-    public static Result VerifySaveData(this FileSystemClient fs, out bool isValid, SaveDataSpaceId spaceId,
-        ulong saveDataId, Span<byte> workBuffer)
-    {
-        UnsafeHelpers.SkipParamInit(out isValid);
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.VerifySaveDataFileSystemBySaveDataSpaceId(spaceId, saveDataId,
-            new OutBuffer(workBuffer));
-
-        if (ResultFs.DataCorrupted.Includes(rc))
-        {
-            isValid = false;
+            availableSize = extraData.DataSize;
             return Result.Success;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-
-        if (rc.IsSuccess())
+        public static Result GetSaveDataAvailableSize(this FileSystemClientImpl fs, out long availableSize,
+            SaveDataSpaceId spaceId, ulong saveDataId)
         {
-            isValid = true;
+            UnsafeHelpers.SkipParamInit(out availableSize);
+
+            Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId, saveDataId);
+            if (rc.IsFailure()) return rc;
+
+            availableSize = extraData.DataSize;
             return Result.Success;
         }
 
-        return rc;
-    }
-
-    public static Result CorruptSaveDataForDebug(this FileSystemClient fs, ulong saveDataId)
-    {
-        return CorruptSaveDataForDebug(fs, SaveDataSpaceId.System, saveDataId);
-    }
-
-    public static Result CorruptSaveDataForDebug(this FileSystemClient fs, SaveDataSpaceId spaceId,
-        ulong saveDataId)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.CorruptSaveDataFileSystemBySaveDataSpaceId(spaceId, saveDataId);
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result CorruptSaveDataForDebug(this FileSystemClient fs, SaveDataSpaceId spaceId,
-        ulong saveDataId, long offset)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.CorruptSaveDataFileSystemByOffset(spaceId, saveDataId, offset);
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static void DisableAutoSaveDataCreation(this FileSystemClient fs)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-        Result rc = fileSystemProxy.Get.DisableAutoSaveDataCreation();
-
-        fs.Impl.LogResultErrorMessage(rc);
-        Abort.DoAbortUnless(rc.IsSuccess());
-    }
-
-    public static Result DeleteCacheStorage(this FileSystemClient fs, int index)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x20];
-
-        if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+        public static Result GetSaveDataAvailableSize(this FileSystemClient fs, out long availableSize,
+            ulong saveDataId)
         {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = Delete(fs, index);
-            Tick end = fs.Hos.Os.GetSystemTick();
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x40];
 
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogIndex).AppendFormat(index, 'd');
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = Delete(fs, index);
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result Delete(FileSystemClient fs, int index)
+        public static Result GetSaveDataAvailableSize(this FileSystemClient fs, out long availableSize,
+            SaveDataSpaceId spaceId, ulong saveDataId)
         {
-            if (index < 0)
-                return ResultFs.InvalidArgument.Log();
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
 
-            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
 
-            return fileSystemProxy.Get.DeleteCacheStorage((ushort)index);
-        }
-    }
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
 
-    public static Result GetCacheStorageSize(this FileSystemClient fs, out long saveSize, out long journalSize,
-        int index)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x60];
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
 
-        if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetSize(fs, out saveSize, out journalSize, index);
-            Tick end = fs.Hos.Os.GetSystemTick();
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.GetSaveDataAvailableSize(out availableSize, spaceId, saveDataId);
+            }
 
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogIndex).AppendFormat(index, 'd')
-                .Append(LogSaveDataSize).AppendFormat(AccessLogImpl.DereferenceOutValue(in saveSize, rc), 'd')
-                .Append(LogSaveDataJournalSize)
-                .AppendFormat(AccessLogImpl.DereferenceOutValue(in journalSize, rc), 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetSize(fs, out saveSize, out journalSize, index);
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
         }
 
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetSize(FileSystemClient fs, out long saveSize, out long journalSize, int index)
+        public static Result GetSaveDataJournalSize(this FileSystemClientImpl fs, out long journalSize,
+            ulong saveDataId)
         {
-            UnsafeHelpers.SkipParamInit(out saveSize, out journalSize);
+            UnsafeHelpers.SkipParamInit(out journalSize);
 
-            if (index < 0)
-                return ResultFs.InvalidArgument.Log();
-
-            // Note: Nintendo gets the service object in the outer function and captures it for the inner function
-            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-            return fileSystemProxy.Get.GetCacheStorageSize(out saveSize, out journalSize, (ushort)index);
-        }
-    }
-
-    public static Result UpdateSaveDataMacForDebug(this FileSystemClient fs, SaveDataSpaceId spaceId,
-        ulong saveDataId)
-    {
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-        return fileSystemProxy.Get.UpdateSaveDataMacForDebug(spaceId, saveDataId);
-    }
-
-    public static Result ListApplicationAccessibleSaveDataOwnerId(this FileSystemClient fs, out int readCount,
-        Span<Ncm.ApplicationId> idBuffer, Ncm.ApplicationId applicationId, int programIndex, int startIndex)
-    {
-        if (idBuffer.IsEmpty)
-        {
-            readCount = 0;
-            return Result.Success;
-        }
-
-        using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
-
-        var programId = new ProgramId(applicationId.Value + (uint)programIndex);
-        OutBuffer idOutBuffer = OutBuffer.FromSpan(idBuffer);
-
-        Result rc = fileSystemProxy.Get.ListAccessibleSaveDataOwnerId(out readCount, idOutBuffer, programId, startIndex,
-            idBuffer.Length);
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-    }
-
-    public static Result GetSaveDataRestoreFlag(this FileSystemClient fs, out bool isRestoreFlagSet,
-        U8Span mountName)
-    {
-        UnsafeHelpers.SkipParamInit(out isRestoreFlagSet);
-
-        Result rc;
-        FileSystemAccessor fileSystem;
-        Span<byte> logBuffer = stackalloc byte[0x40];
-
-        if (fs.Impl.IsEnabledAccessLog())
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = fs.Impl.Find(out fileSystem, mountName);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogName).Append(mountName).Append(LogQuote);
-
-            fs.Impl.OutputAccessLogUnlessResultSuccess(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = fs.Impl.Find(out fileSystem, mountName);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        if (rc.IsFailure()) return rc;
-
-        if (fs.Impl.IsEnabledAccessLog() && fileSystem.IsEnabledAccessLog())
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetRestoreFlagValue(fs, out isRestoreFlagSet, fileSystem);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            ReadOnlySpan<byte> isSetString =
-                AccessLogImpl.ConvertFromBoolToAccessLogBooleanValue(
-                    AccessLogImpl.DereferenceOutValue(in isRestoreFlagSet, rc));
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogName).Append(mountName).Append(LogQuote)
-                .Append(LogRestoreFlag).Append(isSetString);
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetRestoreFlagValue(fs, out isRestoreFlagSet, fileSystem);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetRestoreFlagValue(FileSystemClient fs, out bool isRestoreFlagSet,
-            FileSystemAccessor fileSystem)
-        {
-            Unsafe.SkipInit(out isRestoreFlagSet);
-
-            if (fileSystem is null)
-                return ResultFs.NullptrArgument.Log();
-
-            Result rc = fileSystem.GetSaveDataAttribute(out SaveDataAttribute attribute);
+            Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, saveDataId);
             if (rc.IsFailure()) return rc;
 
-            if (attribute.ProgramId == Fs.SaveData.InvalidProgramId)
-                attribute.ProgramId = Fs.SaveData.AutoResolveCallerProgramId;
-
-            var extraDataMask = new SaveDataExtraData();
-            extraDataMask.Flags = SaveDataFlags.Restore;
-
-            rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, SaveDataSpaceId.User,
-                in attribute, in extraDataMask);
-            if (rc.IsFailure()) return rc;
-
-            isRestoreFlagSet = extraData.Flags.HasFlag(SaveDataFlags.Restore);
-            return Result.Success;
-        }
-    }
-
-    public static Result GetDeviceSaveDataSize(this FileSystemClient fs, out long saveSize,
-        out long journalSize, ApplicationId applicationId)
-    {
-        Result rc;
-        Span<byte> logBuffer = stackalloc byte[0x70];
-
-        if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
-        {
-            Tick start = fs.Hos.Os.GetSystemTick();
-            rc = GetSize(fs, out saveSize, out journalSize, applicationId);
-            Tick end = fs.Hos.Os.GetSystemTick();
-
-            var sb = new U8StringBuilder(logBuffer, true);
-            sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
-                .Append(LogSaveDataSize).AppendFormat(AccessLogImpl.DereferenceOutValue(in saveSize, rc), 'd')
-                .Append(LogSaveDataJournalSize)
-                .AppendFormat(AccessLogImpl.DereferenceOutValue(in journalSize, rc), 'd');
-
-            fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
-        }
-        else
-        {
-            rc = GetSize(fs, out saveSize, out journalSize, applicationId);
-        }
-
-        fs.Impl.AbortIfNeeded(rc);
-        return rc;
-
-        static Result GetSize(FileSystemClient fs, out long saveSize, out long journalSize,
-            ApplicationId applicationId)
-        {
-            UnsafeHelpers.SkipParamInit(out saveSize, out journalSize);
-
-            var extraDataMask = new SaveDataExtraData();
-            extraDataMask.DataSize = unchecked((long)0xFFFFFFFFFFFFFFFF);
-            extraDataMask.JournalSize = unchecked((long)0xFFFFFFFFFFFFFFFF);
-
-            Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, new ProgramId(applicationId.Value),
-                SaveDataType.Device, Fs.SaveData.InvalidUserId, 0);
-            if (rc.IsFailure()) return rc;
-
-            rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, SaveDataSpaceId.User,
-                in attribute, in extraDataMask);
-            if (rc.IsFailure()) return rc;
-
-            saveSize = extraData.DataSize;
             journalSize = extraData.JournalSize;
-
             return Result.Success;
         }
+
+        public static Result GetSaveDataJournalSize(this FileSystemClientImpl fs, out long journalSize,
+            SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            UnsafeHelpers.SkipParamInit(out journalSize);
+
+            Result rc = fs.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, spaceId, saveDataId);
+            if (rc.IsFailure()) return rc;
+
+            journalSize = extraData.JournalSize;
+            return Result.Success;
+        }
+
+        public static Result GetSaveDataJournalSize(this FileSystemClient fs, out long journalSize, ulong saveDataId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x40];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.GetSaveDataJournalSize(out journalSize, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.GetSaveDataJournalSize(out journalSize, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result GetSaveDataJournalSize(this FileSystemClient fs, out long journalSize,
+            SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.GetSaveDataJournalSize(out journalSize, spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.GetSaveDataJournalSize(out journalSize, spaceId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result GetSaveDataCommitId(this FileSystemClient fs, out long commitId, SaveDataSpaceId spaceId,
+            ulong saveDataId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetCommitId(fs, out commitId, spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetCommitId(fs, out commitId, spaceId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetCommitId(FileSystemClient fs, out long commitId, SaveDataSpaceId spaceId, ulong saveDataId)
+            {
+                UnsafeHelpers.SkipParamInit(out commitId);
+
+                using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+                return fileSystemProxy.Get.GetSaveDataCommitId(out commitId, spaceId, saveDataId);
+            }
+        }
+
+        public static Result SetSaveDataCommitId(this FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId,
+            long commitId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x80];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = SetCommitId(fs, spaceId, saveDataId, commitId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataId).AppendFormat(saveDataId, 'X')
+                    .Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataCommitId).AppendFormat(commitId, 'X', 16);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = SetCommitId(fs, spaceId, saveDataId, commitId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result SetCommitId(FileSystemClient fs, SaveDataSpaceId spaceId, ulong saveDataId, long commitId)
+            {
+                SaveDataExtraData extraDataMask = default;
+                extraDataMask.CommitId = unchecked((long)0xFFFFFFFFFFFFFFFF);
+
+                SaveDataExtraData extraData = default;
+                extraData.CommitId = commitId;
+
+                return fs.Impl.WriteSaveDataFileSystemExtraData(spaceId, saveDataId, in extraData, in extraDataMask);
+            }
+        }
+
+        public static Result QuerySaveDataInternalStorageTotalSize(this FileSystemClientImpl fs, out long size,
+            SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            UnsafeHelpers.SkipParamInit(out size);
+
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.GetFileSystemProxyServiceObject();
+
+            return fileSystemProxy.Get.QuerySaveDataInternalStorageTotalSize(out size, spaceId, saveDataId);
+        }
+
+        public static Result QuerySaveDataInternalStorageTotalSize(this FileSystemClient fs, out long size,
+            SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x50];
+
+            if (fs.Impl.IsEnabledAccessLog(AccessLogTarget.System) && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.QuerySaveDataInternalStorageTotalSize(out size, spaceId, saveDataId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var idString = new IdString();
+                var sb = new U8StringBuilder(logBuffer, true);
+
+                sb.Append(LogSaveDataSpaceId).Append(idString.ToString(spaceId))
+                    .Append(LogSaveDataId).AppendFormat(saveDataId, 'X');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.QuerySaveDataInternalStorageTotalSize(out size, spaceId, saveDataId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result VerifySaveData(this FileSystemClient fs, out bool isValid, ulong saveDataId,
+            Span<byte> workBuffer)
+        {
+            return VerifySaveData(fs, out isValid, SaveDataSpaceId.System, saveDataId, workBuffer);
+        }
+
+        public static Result VerifySaveData(this FileSystemClient fs, out bool isValid, SaveDataSpaceId spaceId,
+            ulong saveDataId, Span<byte> workBuffer)
+        {
+            UnsafeHelpers.SkipParamInit(out isValid);
+
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.VerifySaveDataFileSystemBySaveDataSpaceId(spaceId, saveDataId,
+                new OutBuffer(workBuffer));
+
+            if (ResultFs.DataCorrupted.Includes(rc))
+            {
+                isValid = false;
+                return Result.Success;
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+
+            if (rc.IsSuccess())
+            {
+                isValid = true;
+                return Result.Success;
+            }
+
+            return rc;
+        }
+
+        public static Result CorruptSaveDataForDebug(this FileSystemClient fs, ulong saveDataId)
+        {
+            return CorruptSaveDataForDebug(fs, SaveDataSpaceId.System, saveDataId);
+        }
+
+        public static Result CorruptSaveDataForDebug(this FileSystemClient fs, SaveDataSpaceId spaceId,
+            ulong saveDataId)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.CorruptSaveDataFileSystemBySaveDataSpaceId(spaceId, saveDataId);
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result CorruptSaveDataForDebug(this FileSystemClient fs, SaveDataSpaceId spaceId,
+            ulong saveDataId, long offset)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.CorruptSaveDataFileSystemByOffset(spaceId, saveDataId, offset);
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static void DisableAutoSaveDataCreation(this FileSystemClient fs)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.DisableAutoSaveDataCreation();
+
+            fs.Impl.LogResultErrorMessage(rc);
+            Abort.DoAbortUnless(rc.IsSuccess());
+        }
+
+        public static Result DeleteCacheStorage(this FileSystemClient fs, int index)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x20];
+
+            if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = Delete(fs, index);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogIndex).AppendFormat(index, 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = Delete(fs, index);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result Delete(FileSystemClient fs, int index)
+            {
+                if (index < 0)
+                    return ResultFs.InvalidArgument.Log();
+
+                using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+                return fileSystemProxy.Get.DeleteCacheStorage((ushort)index);
+            }
+        }
+
+        public static Result GetCacheStorageSize(this FileSystemClient fs, out long saveSize, out long journalSize,
+            int index)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x60];
+
+            if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetSize(fs, out saveSize, out journalSize, index);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogIndex).AppendFormat(index, 'd')
+                    .Append(LogSaveDataSize).AppendFormat(AccessLogImpl.DereferenceOutValue(in saveSize, rc), 'd')
+                    .Append(LogSaveDataJournalSize)
+                    .AppendFormat(AccessLogImpl.DereferenceOutValue(in journalSize, rc), 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetSize(fs, out saveSize, out journalSize, index);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetSize(FileSystemClient fs, out long saveSize, out long journalSize, int index)
+            {
+                UnsafeHelpers.SkipParamInit(out saveSize, out journalSize);
+
+                if (index < 0)
+                    return ResultFs.InvalidArgument.Log();
+
+                // Note: Nintendo gets the service object in the outer function and captures it for the inner function
+                using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+                return fileSystemProxy.Get.GetCacheStorageSize(out saveSize, out journalSize, (ushort)index);
+            }
+        }
+
+        public static Result OpenCacheStorageList(this FileSystemClient fs, out CacheStorageListHandle handle)
+        {
+            UnsafeHelpers.SkipParamInit(out handle);
+
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x40];
+
+            CacheStorageListCache listCache;
+
+            if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = Open(fs, out listCache);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogCacheStorageListHandle).AppendFormat(listCache.GetHashCode(), 'x');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = Open(fs, out listCache);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc.Miss();
+
+            handle = new CacheStorageListHandle(listCache);
+            return Result.Success;
+
+            static Result Open(FileSystemClient fs, out CacheStorageListCache listCache)
+            {
+                UnsafeHelpers.SkipParamInit(out listCache);
+                CacheStorageListCache tempListCache = null;
+
+                Result rc = Utility.DoContinuouslyUntilSaveDataListFetched(fs.Hos, () =>
+                {
+                    // Note: Nintendo uses the same CacheStorageListCache for every attempt to fetch the save data list
+                    // without clearing it between runs. This means that if it has to retry fetching the list, the
+                    // CacheStorageListCache may contain duplicate entries if the save data indexer was reset while this
+                    // function was running.
+                    tempListCache = new CacheStorageListCache();
+
+                    using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+                    using var reader = new SharedRef<ISaveDataInfoReader>();
+
+                    Result result = fileSystemProxy.Get.OpenSaveDataInfoReaderOnlyCacheStorage(ref reader.Ref());
+                    if (result.IsFailure()) return result.Miss();
+
+                    while (true)
+                    {
+                        Unsafe.SkipInit(out SaveDataInfo info);
+
+                        result = reader.Get.Read(out long readCount, new OutBuffer(SpanHelpers.AsByteSpan(ref info)));
+                        if (result.IsFailure()) return result.Miss();
+
+                        if (readCount == 0)
+                            break;
+
+                        var cacheEntry = new CacheStorageListCache.CacheEntry(info.Index);
+                        result = tempListCache.PushBack(in cacheEntry);
+                        if (result.IsFailure()) return result.Miss();
+                    }
+
+                    return Result.Success;
+                });
+                if (rc.IsFailure()) return rc.Miss();
+
+                Assert.SdkRequiresNotNull(tempListCache);
+
+                listCache = tempListCache;
+                return Result.Success;
+            }
+        }
+
+        public static Result ReadCacheStorageList(this FileSystemClient fs, out int storageInfoReadCount,
+            Span<CacheStorageInfo> storageInfoBuffer, CacheStorageListHandle handle)
+        {
+            UnsafeHelpers.SkipParamInit(out storageInfoReadCount);
+
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x70];
+
+            if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = Read(out storageInfoReadCount, storageInfoBuffer, handle);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogCacheStorageListHandle).AppendFormat(handle.Cache.GetHashCode(), 'x')
+                    .Append(LogInfoBufferCount).AppendFormat(storageInfoBuffer.Length, 'X')
+                    .Append(LogCacheStorageCount).AppendFormat(AccessLogImpl.DereferenceOutValue(in storageInfoReadCount, rc), 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = Read(out storageInfoReadCount, storageInfoBuffer, handle);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc.Miss();
+
+            return Result.Success;
+
+            static Result Read(out int storageCount, Span<CacheStorageInfo> infoBuffer, CacheStorageListHandle handle)
+            {
+                int count = 0;
+
+                var listCache = CacheStorageListCache.GetCacheStorageListCache(handle);
+
+                while (count < infoBuffer.Length)
+                {
+                    ref readonly CacheStorageListCache.CacheEntry entry = ref listCache.PopFront();
+
+                    // We're done iterating if we get a null ref
+                    if (Unsafe.IsNullRef(ref Unsafe.AsRef(in entry)))
+                        break;
+
+                    infoBuffer[count] = default;
+                    infoBuffer[count].Index = entry.GetCacheStorageIndex();
+                    count++;
+                }
+
+                storageCount = count;
+                return Result.Success;
+            }
+        }
+
+        public static void CloseCacheStorageList(this FileSystemClient fs, CacheStorageListHandle handle)
+        {
+            Span<byte> logBuffer = stackalloc byte[0x40];
+
+            var listCache = CacheStorageListCache.GetCacheStorageListCache(handle);
+
+            listCache?.Dispose();
+
+            if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogCacheStorageListHandle).AppendFormat(handle.Cache.GetHashCode(), 'x');
+
+                fs.Impl.OutputAccessLog(Result.Success, start, end, null, new U8Span(sb.Buffer));
+            }
+        }
+
+        public static Result UpdateSaveDataMacForDebug(this FileSystemClient fs, SaveDataSpaceId spaceId,
+            ulong saveDataId)
+        {
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+            Result rc = fileSystemProxy.Get.UpdateSaveDataMacForDebug(spaceId, saveDataId);
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result ListApplicationAccessibleSaveDataOwnerId(this FileSystemClient fs, out int readCount,
+            Span<Ncm.ApplicationId> idBuffer, Ncm.ApplicationId applicationId, int programIndex, int startIndex)
+        {
+            if (idBuffer.IsEmpty)
+            {
+                readCount = 0;
+                return Result.Success;
+            }
+
+            using SharedRef<IFileSystemProxy> fileSystemProxy = fs.Impl.GetFileSystemProxyServiceObject();
+
+            var programId = new ProgramId(applicationId.Value + (uint)programIndex);
+            OutBuffer idOutBuffer = OutBuffer.FromSpan(idBuffer);
+
+            Result rc = fileSystemProxy.Get.ListAccessibleSaveDataOwnerId(out readCount, idOutBuffer, programId, startIndex,
+                idBuffer.Length);
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+        }
+
+        public static Result GetSaveDataRestoreFlag(this FileSystemClient fs, out bool isRestoreFlagSet,
+            U8Span mountName)
+        {
+            UnsafeHelpers.SkipParamInit(out isRestoreFlagSet);
+
+            Result rc;
+            FileSystemAccessor fileSystem;
+            Span<byte> logBuffer = stackalloc byte[0x40];
+
+            if (fs.Impl.IsEnabledAccessLog())
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = fs.Impl.Find(out fileSystem, mountName);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogName).Append(mountName).Append(LogQuote);
+
+                fs.Impl.OutputAccessLogUnlessResultSuccess(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = fs.Impl.Find(out fileSystem, mountName);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            if (rc.IsFailure()) return rc;
+
+            if (fs.Impl.IsEnabledAccessLog() && fileSystem.IsEnabledAccessLog())
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetRestoreFlagValue(fs, out isRestoreFlagSet, fileSystem);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                ReadOnlySpan<byte> isSetString =
+                    AccessLogImpl.ConvertFromBoolToAccessLogBooleanValue(
+                        AccessLogImpl.DereferenceOutValue(in isRestoreFlagSet, rc));
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogName).Append(mountName).Append(LogQuote)
+                    .Append(LogRestoreFlag).Append(isSetString);
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetRestoreFlagValue(fs, out isRestoreFlagSet, fileSystem);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetRestoreFlagValue(FileSystemClient fs, out bool isRestoreFlagSet,
+                FileSystemAccessor fileSystem)
+            {
+                Unsafe.SkipInit(out isRestoreFlagSet);
+
+                if (fileSystem is null)
+                    return ResultFs.NullptrArgument.Log();
+
+                Result rc = fileSystem.GetSaveDataAttribute(out SaveDataAttribute attribute);
+                if (rc.IsFailure()) return rc;
+
+                if (attribute.ProgramId == Fs.SaveData.InvalidProgramId)
+                    attribute.ProgramId = Fs.SaveData.AutoResolveCallerProgramId;
+
+                SaveDataExtraData extraDataMask = default;
+                extraDataMask.Flags = SaveDataFlags.Restore;
+
+                rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, SaveDataSpaceId.User,
+                    in attribute, in extraDataMask);
+                if (rc.IsFailure()) return rc;
+
+                isRestoreFlagSet = extraData.Flags.HasFlag(SaveDataFlags.Restore);
+                return Result.Success;
+            }
+        }
+
+        public static Result GetDeviceSaveDataSize(this FileSystemClient fs, out long saveSize,
+            out long journalSize, ApplicationId applicationId)
+        {
+            Result rc;
+            Span<byte> logBuffer = stackalloc byte[0x70];
+
+            if (fs.Impl.IsEnabledAccessLog() && fs.Impl.IsEnabledHandleAccessLog(null))
+            {
+                Tick start = fs.Hos.Os.GetSystemTick();
+                rc = GetSize(fs, out saveSize, out journalSize, applicationId);
+                Tick end = fs.Hos.Os.GetSystemTick();
+
+                var sb = new U8StringBuilder(logBuffer, true);
+                sb.Append(LogApplicationId).AppendFormat(applicationId.Value, 'X')
+                    .Append(LogSaveDataSize).AppendFormat(AccessLogImpl.DereferenceOutValue(in saveSize, rc), 'd')
+                    .Append(LogSaveDataJournalSize)
+                    .AppendFormat(AccessLogImpl.DereferenceOutValue(in journalSize, rc), 'd');
+
+                fs.Impl.OutputAccessLog(rc, start, end, null, new U8Span(sb.Buffer));
+            }
+            else
+            {
+                rc = GetSize(fs, out saveSize, out journalSize, applicationId);
+            }
+
+            fs.Impl.AbortIfNeeded(rc);
+            return rc;
+
+            static Result GetSize(FileSystemClient fs, out long saveSize, out long journalSize,
+                ApplicationId applicationId)
+            {
+                UnsafeHelpers.SkipParamInit(out saveSize, out journalSize);
+
+                SaveDataExtraData extraDataMask = default;
+                extraDataMask.DataSize = unchecked((long)0xFFFFFFFFFFFFFFFF);
+                extraDataMask.JournalSize = unchecked((long)0xFFFFFFFFFFFFFFFF);
+
+                Result rc = SaveDataAttribute.Make(out SaveDataAttribute attribute, new ProgramId(applicationId.Value),
+                    SaveDataType.Device, Fs.SaveData.InvalidUserId, staticSaveDataId: 0);
+                if (rc.IsFailure()) return rc;
+
+                rc = fs.Impl.ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, SaveDataSpaceId.User,
+                    in attribute, in extraDataMask);
+                if (rc.IsFailure()) return rc;
+
+                saveSize = extraData.DataSize;
+                journalSize = extraData.JournalSize;
+
+                return Result.Success;
+            }
+        }
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/Fs/Utility.cs b/src/LibHac/Fs/Utility.cs
new file mode 100644
index 00000000..955c983f
--- /dev/null
+++ b/src/LibHac/Fs/Utility.cs
@@ -0,0 +1,50 @@
+using System;
+using LibHac.Account;
+using LibHac.Os;
+
+namespace LibHac.Fs;
+
+/// <summary>
+/// Contains various utility functions used by FS client code.
+/// </summary>
+/// <remarks>Based on nnSdk 13.4.0</remarks>
+public static class Utility
+{
+    public static UserId ConvertAccountUidToFsUserId(Uid uid)
+    {
+        return new UserId(uid.Id.High, uid.Id.Low);
+    }
+
+    public static Result CheckUid(HorizonClient hos, Uid uid)
+    {
+        throw new NotImplementedException();
+    }
+
+    public static Result DoContinuouslyUntilSaveDataListFetched(HorizonClient hos, Func<Result> listGetter)
+    {
+        const int maxTryCount = 5;
+        const int initialSleepTimeMs = 5;
+        const int sleepTimeMultiplier = 2;
+
+        Result lastResult = Result.Success;
+        long sleepTime = initialSleepTimeMs;
+
+        for (int i = 0; i < maxTryCount; i++)
+        {
+            Result rc = listGetter();
+
+            if (rc.IsSuccess())
+                return rc;
+
+            // Try again if any save data were added or removed while getting the list
+            if (!ResultFs.InvalidHandle.Includes(rc))
+                return rc.Miss();
+
+            lastResult = rc;
+            hos.Os.SleepThread(TimeSpan.FromMilliSeconds(sleepTime));
+            sleepTime *= sleepTimeMultiplier;
+        }
+
+        return lastResult.Log();
+    }
+}
\ No newline at end of file
diff --git a/src/LibHac/FsSrv/FileSystemProxyCoreImpl.cs b/src/LibHac/FsSrv/FileSystemProxyCoreImpl.cs
index c4e30339..46872992 100644
--- a/src/LibHac/FsSrv/FileSystemProxyCoreImpl.cs
+++ b/src/LibHac/FsSrv/FileSystemProxyCoreImpl.cs
@@ -6,7 +6,8 @@ using LibHac.Fs;
 using LibHac.Fs.Fsa;
 using LibHac.Fs.Shim;
 using LibHac.FsSrv.FsCreator;
-using LibHac.FsSrv.Impl;
+
+using Utility = LibHac.FsSrv.Impl.Utility;
 
 namespace LibHac.FsSrv;
 
diff --git a/src/LibHac/FsSrv/FsCreator/EmulatedBisFileSystemCreator.cs b/src/LibHac/FsSrv/FsCreator/EmulatedBisFileSystemCreator.cs
index 9255f1b2..368d66ff 100644
--- a/src/LibHac/FsSrv/FsCreator/EmulatedBisFileSystemCreator.cs
+++ b/src/LibHac/FsSrv/FsCreator/EmulatedBisFileSystemCreator.cs
@@ -2,7 +2,8 @@
 using LibHac.Common;
 using LibHac.Fs;
 using LibHac.Fs.Fsa;
-using LibHac.FsSrv.Impl;
+
+using Utility = LibHac.FsSrv.Impl.Utility;
 
 namespace LibHac.FsSrv.FsCreator;
 
@@ -134,4 +135,4 @@ public class EmulatedBisFileSystemCreator : IBuiltInStorageFileSystemCreator
                 return string.Empty;
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/FsSrv/FsCreator/EmulatedSdCardFileSystemCreator.cs b/src/LibHac/FsSrv/FsCreator/EmulatedSdCardFileSystemCreator.cs
index ef4a5234..b7359146 100644
--- a/src/LibHac/FsSrv/FsCreator/EmulatedSdCardFileSystemCreator.cs
+++ b/src/LibHac/FsSrv/FsCreator/EmulatedSdCardFileSystemCreator.cs
@@ -2,9 +2,10 @@
 using LibHac.Common;
 using LibHac.Fs;
 using LibHac.Fs.Fsa;
-using LibHac.FsSrv.Impl;
 using LibHac.Util;
 
+using Utility = LibHac.FsSrv.Impl.Utility;
+
 namespace LibHac.FsSrv.FsCreator;
 
 public class EmulatedSdCardFileSystemCreator : ISdCardProxyFileSystemCreator, IDisposable
@@ -85,4 +86,4 @@ public class EmulatedSdCardFileSystemCreator : ISdCardProxyFileSystemCreator, ID
     {
         throw new NotImplementedException();
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/Tools/FsSystem/FileSystemExtensions.cs b/src/LibHac/Tools/FsSystem/FileSystemExtensions.cs
index 4df57c9d..72c0c451 100644
--- a/src/LibHac/Tools/FsSystem/FileSystemExtensions.cs
+++ b/src/LibHac/Tools/FsSystem/FileSystemExtensions.cs
@@ -10,6 +10,7 @@ using LibHac.FsSystem;
 using LibHac.Tools.Fs;
 using LibHac.Util;
 using Path = LibHac.Fs.Path;
+using Utility = LibHac.FsSystem.Utility;
 
 namespace LibHac.Tools.FsSystem;
 
diff --git a/tests/LibHac.Tests/Fs/FileSystemClientTests/ApplicationSaveDataManagementTests.cs b/tests/LibHac.Tests/Fs/FileSystemClientTests/ApplicationSaveDataManagementTests.cs
index 560d8dae..97f3d8d5 100644
--- a/tests/LibHac.Tests/Fs/FileSystemClientTests/ApplicationSaveDataManagementTests.cs
+++ b/tests/LibHac.Tests/Fs/FileSystemClientTests/ApplicationSaveDataManagementTests.cs
@@ -35,7 +35,7 @@ public class ApplicationSaveDataManagementTests
 
         Assert.Equal(1, entriesRead);
         Assert.Equal(applicationId, info[0].ProgramId);
-        Assert.Equal(ConvertAccountUidToFsUserId(userId), info[0].UserId);
+        Assert.Equal(Utility.ConvertAccountUidToFsUserId(userId), info[0].UserId);
         Assert.Equal(SaveDataType.Account, info[0].Type);
     }
 
diff --git a/tests/LibHac.Tests/Fs/FileSystemClientTests/ShimTests/SaveDataManagement.cs b/tests/LibHac.Tests/Fs/FileSystemClientTests/ShimTests/SaveDataManagement.cs
index 5bf97d8c..dda8a063 100644
--- a/tests/LibHac.Tests/Fs/FileSystemClientTests/ShimTests/SaveDataManagement.cs
+++ b/tests/LibHac.Tests/Fs/FileSystemClientTests/ShimTests/SaveDataManagement.cs
@@ -577,6 +577,73 @@ public class SaveDataManagement
         Assert.Equal(timeStamp, actualTimeStamp);
     }
 
+    [Fact]
+    public void OpenCacheStorageList_ReadIntoLargeBuffer_AllIndexesAreRead()
+    {
+        var applicationId = new Ncm.ApplicationId(1);
+
+        Horizon hos = HorizonFactory.CreateBasicHorizon();
+
+        HorizonClient client = hos.CreateHorizonClient(new ProgramLocation(applicationId, StorageId.BuiltInSystem),
+            (AccessControlBits.Bits)ulong.MaxValue);
+
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 0, 0, 0, SaveDataFlags.None));
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 6, 0, 0, SaveDataFlags.None));
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 2, 0, 0, SaveDataFlags.None));
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 3, 0, 0, SaveDataFlags.None));
+
+        Assert.Success(client.Fs.OpenCacheStorageList(out CacheStorageListHandle handle));
+        var infoBuffer = new CacheStorageInfo[5];
+
+        Assert.Success(client.Fs.ReadCacheStorageList(out int readCount, infoBuffer, handle));
+
+        Assert.Equal(4, readCount);
+
+        Assert.Equal(0, infoBuffer[0].Index);
+        Assert.Equal(2, infoBuffer[1].Index);
+        Assert.Equal(3, infoBuffer[2].Index);
+        Assert.Equal(6, infoBuffer[3].Index);
+
+        client.Fs.CloseCacheStorageList(handle);
+    }
+
+    [Fact]
+    public void OpenCacheStorageList_ReadIntoMultipleBuffers_AllIndexesAreRead()
+    {
+        var applicationId = new Ncm.ApplicationId(1);
+
+        Horizon hos = HorizonFactory.CreateBasicHorizon();
+
+        HorizonClient client = hos.CreateHorizonClient(new ProgramLocation(applicationId, StorageId.BuiltInSystem),
+            (AccessControlBits.Bits)ulong.MaxValue);
+
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 0, 0, 0, SaveDataFlags.None));
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 6, 0, 0, SaveDataFlags.None));
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 2, 0, 0, SaveDataFlags.None));
+        Assert.Success(client.Fs.CreateCacheStorage(applicationId, SaveDataSpaceId.User, applicationId.Value, 3, 0, 0, SaveDataFlags.None));
+
+        Assert.Success(client.Fs.OpenCacheStorageList(out CacheStorageListHandle handle));
+        var infoBuffer = new CacheStorageInfo[2];
+
+        Assert.Success(client.Fs.ReadCacheStorageList(out int readCount, infoBuffer, handle));
+
+        Assert.Equal(2, readCount);
+        Assert.Equal(0, infoBuffer[0].Index);
+        Assert.Equal(2, infoBuffer[1].Index);
+
+        Assert.Success(client.Fs.ReadCacheStorageList(out readCount, infoBuffer, handle));
+
+        Assert.Equal(2, readCount);
+        Assert.Equal(3, infoBuffer[0].Index);
+        Assert.Equal(6, infoBuffer[1].Index);
+
+        Assert.Success(client.Fs.ReadCacheStorageList(out readCount, infoBuffer, handle));
+
+        Assert.Equal(0, readCount);
+
+        client.Fs.CloseCacheStorageList(handle);
+    }
+
     private static Result PopulateSaveData(FileSystemClient fs, int count, int seed = -1)
     {
         if (seed == -1)
diff --git a/tests/LibHac.Tests/Fs/TypeLayoutTests.cs b/tests/LibHac.Tests/Fs/TypeLayoutTests.cs
index bbef6c80..363850a6 100644
--- a/tests/LibHac.Tests/Fs/TypeLayoutTests.cs
+++ b/tests/LibHac.Tests/Fs/TypeLayoutTests.cs
@@ -354,4 +354,15 @@ public class TypeLayoutTests
         Assert.Equal(3, GetOffset(in s, in s.CompressionRate));
         Assert.Equal(4, GetOffset(in s, in s.Reserved));
     }
+
+    [Fact]
+    public static void CacheStorageInfo_Layout()
+    {
+        var s = new CacheStorageInfo();
+
+        Assert.Equal(0x20, Unsafe.SizeOf<CacheStorageInfo>());
+
+        Assert.Equal(0, GetOffset(in s, in s.Index));
+        Assert.Equal(4, GetOffset(in s, in s.Reserved));
+    }
 }
\ No newline at end of file