Separate fssrv save code to SaveDataFileSystemService

DotnetCliVersion.txt

@@ -1 +1 @@
-3.1.401
+3.1.402

build/CodeGen/results.csv

@@ -267,6 +267,7 @@ Module,DescriptionStart,DescriptionEnd,Name,Summary
 2,6203,,InvalidOpenModeForWrite,
 
 2,6300,6399,UnsupportedOperation,
+2,6301,,UnsupportedCommitTarget,
 2,6302,,UnsupportedOperationInSubStorageSetSize,Attempted to resize a non-resizable SubStorage.
 2,6303,,UnsupportedOperationInResizableSubStorageSetSize,Attempted to resize a SubStorage that wasn't located at the end of the base storage.
 2,6304,,UnsupportedOperationInMemoryStorageSetSize,
@@ -297,10 +298,15 @@ Module,DescriptionStart,DescriptionEnd,Name,Summary
 
 2,6452,,ExternalKeyAlreadyRegistered,
 2,6454,,WriteStateUnflushed,
+2,6456,,DirectoryNotClosed,
 2,6457,,WriteModeFileNotClosed,
+2,6458,,AllocatorAlreadyRegistered,
+2,6459,,DefaultAllocatorUsed,
 2,6461,,AllocatorAlignmentViolation,
 2,6463,,MultiCommitFileSystemAlreadyAdded,The provided file system has already been added to the multi-commit manager.
 2,6465,,UserNotExist,
+2,6466,,DefaultGlobalFileDataCacheEnabled,
+2,6467,,SaveDataRootPathUnavailable,
 
 2,6600,6699,EntryNotFound,
 2,6605,,TargetProgramNotFound,Specified program is not found in the program registry.

src/LibHac/Boot/Package1.cs

@@ -502,7 +502,7 @@ namespace LibHac.Boot
                     Package1Section.Bootloader => 0,
                     Package1Section.SecureMonitor => 1,
                     Package1Section.WarmBoot => 2,
-                    _ => -1,
+                    _ => -1
                 };
             }
 
@@ -513,7 +513,7 @@ namespace LibHac.Boot
                     Package1Section.Bootloader => 1,
                     Package1Section.SecureMonitor => 2,
                     Package1Section.WarmBoot => 0,
-                    _ => -1,
+                    _ => -1
                 };
             }
 
@@ -522,7 +522,7 @@ namespace LibHac.Boot
                 Package1Section.Bootloader => 1,
                 Package1Section.SecureMonitor => 0,
                 Package1Section.WarmBoot => 2,
-                _ => -1,
+                _ => -1
             };
         }
 

src/LibHac/Common/Keys/KeyInfo.cs

@@ -31,7 +31,7 @@ namespace LibHac.Common.Keys
             CommonSeedDiff = Common | Seed | DifferentDev,
             CommonDrvd = Common | Derived,
             DeviceRoot = Device | Root,
-            DeviceDrvd = Device | Derived,
+            DeviceDrvd = Device | Derived
         }
 
         public readonly string Name;

src/LibHac/Common/SharedObjectHelpers.cs

@@ -0,0 +1,22 @@
+using System.Runtime.CompilerServices;
+
+namespace LibHac.Common
+{
+    public static class Shared
+    {
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static T Move<T>(ref T value)
+        {
+            T tmp = value;
+            value = default;
+            return tmp;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static void Move<T>(out T dest, ref T value)
+        {
+            dest = value;
+            value = default;
+        }
+    }
+}

src/LibHac/Fs/Accessors/FileSystemAccessor.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using LibHac.Common;
 using LibHac.Fs.Fsa;
+using LibHac.FsSrv.Sf;
 
 namespace LibHac.Fs.Accessors
 {
@@ -20,10 +21,13 @@ namespace LibHac.Fs.Accessors
         private readonly object _locker = new object();
 
         internal bool IsAccessLogEnabled { get; set; }
+        public IMultiCommitTarget MultiCommitTarget { get; }
 
-        public FileSystemAccessor(string name, IFileSystem baseFileSystem, FileSystemClient fsClient, ICommonMountNameGenerator nameGenerator)
+        public FileSystemAccessor(U8Span name, IMultiCommitTarget multiCommitTarget, IFileSystem baseFileSystem,
+            FileSystemClient fsClient, ICommonMountNameGenerator nameGenerator)
         {
-            Name = name;
+            Name = name.ToString();
+            MultiCommitTarget = multiCommitTarget;
             FileSystem = baseFileSystem;
             FsClient = fsClient;
             MountNameGenerator = nameGenerator;
@@ -147,6 +151,11 @@ namespace LibHac.Fs.Accessors
             return MountNameGenerator.GenerateCommonMountName(nameBuffer);
         }
 
+        public ReferenceCountedDisposable<IFileSystemSf> GetMultiCommitTarget()
+        {
+            return MultiCommitTarget?.GetMultiCommitTarget();
+        }
+
         internal void NotifyCloseFile(FileAccessor file)
         {
             lock (_locker)

src/LibHac/Fs/ApplicationSaveDataManagement.cs

@@ -232,7 +232,7 @@ namespace LibHac.Fs
         }
 
         private static Result EnsureApplicationCacheStorageImpl(this FileSystemClient fs, out long requiredSize,
-            out CacheStorageTargetMedia target, Ncm.ApplicationId applicationId, ulong saveDataOwnerId, short index,
+            out CacheStorageTargetMedia target, Ncm.ApplicationId applicationId, ulong saveDataOwnerId, ushort index,
             long dataSize, long journalSize, bool allowExisting)
         {
             requiredSize = default;
@@ -299,7 +299,7 @@ namespace LibHac.Fs
         }
 
         public static Result EnsureApplicationCacheStorage(this FileSystemClient fs, out long requiredSize,
-            out CacheStorageTargetMedia target, Ncm.ApplicationId applicationId, ulong saveDataOwnerId, short index,
+            out CacheStorageTargetMedia target, Ncm.ApplicationId applicationId, ulong saveDataOwnerId, ushort index,
             long dataSize, long journalSize, bool allowExisting)
         {
             return EnsureApplicationCacheStorageImpl(fs, out requiredSize, out target, applicationId, saveDataOwnerId,
@@ -334,7 +334,7 @@ namespace LibHac.Fs
         }
 
         public static Result TryCreateCacheStorage(this FileSystemClient fs, out long requiredSize,
-            SaveDataSpaceId spaceId, Ncm.ApplicationId applicationId, ulong saveDataOwnerId, short index,
+            SaveDataSpaceId spaceId, Ncm.ApplicationId applicationId, ulong saveDataOwnerId, ushort index,
             long dataSize, long journalSize, bool allowExisting)
         {
             requiredSize = default;

src/LibHac/Fs/CommonPaths.cs

@@ -1,8 +1,9 @@
-using LibHac.Common;
+using System;
+using LibHac.Common;
 
 namespace LibHac.Fs
 {
-    internal static class CommonMountNames
+    internal static class CommonPaths
     {
         public const char ReservedMountNamePrefixCharacter = '@';
 
@@ -21,5 +22,11 @@ namespace LibHac.Fs
         public const char GameCardFileSystemMountNameUpdateSuffix = 'U';
         public const char GameCardFileSystemMountNameNormalSuffix = 'N';
         public const char GameCardFileSystemMountNameSecureSuffix = 'S';
+
+        public static ReadOnlySpan<byte> SdCardNintendoRootDirectoryName => // Nintendo
+            new[]
+            {
+                (byte) 'N', (byte) 'i', (byte) 'n', (byte) 't', (byte) 'e', (byte) 'n', (byte) 'd', (byte) 'o'
+            };
     }
 }

src/LibHac/Fs/FileSystemClient.cs

@@ -134,7 +134,13 @@ namespace LibHac.Fs
 
         public Result Register(U8Span mountName, IFileSystem fileSystem, ICommonMountNameGenerator nameGenerator)
         {
-            var accessor = new FileSystemAccessor(mountName.ToString(), fileSystem, this, nameGenerator);
+            return Register(mountName, null, fileSystem, nameGenerator);
+        }
+
+        public Result Register(U8Span mountName, IMultiCommitTarget multiCommitTarget, IFileSystem fileSystem,
+            ICommonMountNameGenerator nameGenerator)
+        {
+            var accessor = new FileSystemAccessor(mountName, multiCommitTarget, fileSystem, this, nameGenerator);
 
             Result rc = MountTable.Mount(accessor);
             if (rc.IsFailure()) return rc;
@@ -173,8 +179,8 @@ namespace LibHac.Fs
             if (path.IsNull())
                 return ResultFs.NullptrArgument.Log();
 
-            int hostMountNameLen = StringUtils.GetLength(CommonMountNames.HostRootFileSystemMountName);
+            int hostMountNameLen = StringUtils.GetLength(CommonPaths.HostRootFileSystemMountName);
-            if (StringUtils.Compare(path, CommonMountNames.HostRootFileSystemMountName, hostMountNameLen) == 0)
+            if (StringUtils.Compare(path, CommonPaths.HostRootFileSystemMountName, hostMountNameLen) == 0)
             {
                 return ResultFs.NotMounted.Log();
             }
@@ -195,7 +201,7 @@ namespace LibHac.Fs
 
             if (PathUtility.IsWindowsDrive(path) || PathUtility.IsUnc(path))
             {
-                StringUtils.Copy(mountName.Name, CommonMountNames.HostRootFileSystemMountName);
+                StringUtils.Copy(mountName.Name, CommonPaths.HostRootFileSystemMountName);
                 mountName.Name[PathTools.MountNameLengthMax] = StringTraits.NullTerminator;
 
                 subPath = path;

src/LibHac/Fs/FsEnums.cs

@@ -96,10 +96,11 @@ namespace LibHac.Fs
     public enum SaveDataState : byte
     {
         Normal = 0,
-        Creating = 1,
+        Processing = 1,
         State2 = 2,
         MarkedForDeletion = 3,
-        Extending = 4
+        Extending = 4,
+        ImportSuspended = 5
     }
 
     public enum ImageDirectoryId
@@ -165,7 +166,8 @@ namespace LibHac.Fs
         KeepAfterResettingSystemSaveData = 1 << 0,
         KeepAfterRefurbishment = 1 << 1,
         KeepAfterResettingSystemSaveDataWithoutUserSaveData = 1 << 2,
-        NeedsSecureDelete = 1 << 3
+        NeedsSecureDelete = 1 << 3,
+        Restore = 1 << 4
     }
 
     public enum SdmmcPort

src/LibHac/Fs/Fsa/IFileSystem.cs

@@ -37,6 +37,31 @@ namespace LibHac.Fs.Fsa
             return DoCreateFile(path, size, option);
         }
 
+        /// <summary>
+        /// Creates or overwrites a file at the specified path.
+        /// </summary>
+        /// <param name="path">The full path of the file to create.</param>
+        /// <param name="size">The initial size of the created file.
+        /// Should usually be <see cref="CreateFileOptions.None"/></param>
+        /// <returns>The <see cref="Result"/> of the requested operation.</returns>
+        /// <remarks>
+        /// The following <see cref="Result"/> codes may be returned under certain conditions:
+        /// 
+        /// The parent directory of the specified path does not exist: <see cref="ResultFs.PathNotFound"/>
+        /// Specified path already exists as either a file or directory: <see cref="ResultFs.PathAlreadyExists"/>
+        /// Insufficient free space to create the file: <see cref="ResultFs.InsufficientFreeSpace"/>
+        /// </remarks>
+        public Result CreateFile(U8Span path, long size)
+        {
+            if (path.IsNull())
+                return ResultFs.NullptrArgument.Log();
+
+            if (size < 0)
+                return ResultFs.OutOfRange.Log();
+
+            return DoCreateFile(path, size, CreateFileOptions.None);
+        }
+
         /// <summary>
         /// Deletes the specified file.
         /// </summary>

src/LibHac/Fs/Impl/FileSystemServiceObjectAdapter.cs

@@ -129,11 +129,19 @@ namespace LibHac.Fs.Impl
             Result rc = GetPathForServiceObject(out Path sfPath, path);
             if (rc.IsFailure()) return rc;
 
-            rc = BaseFs.Target.OpenFile(out ReferenceCountedDisposable<IFileSf> sfFile, in sfPath, (uint)mode);
+            ReferenceCountedDisposable<IFileSf> sfFile = null;
-            if (rc.IsFailure()) return rc;
+            try
+            {
+                rc = BaseFs.Target.OpenFile(out sfFile, in sfPath, (uint)mode);
+                if (rc.IsFailure()) return rc;
 
-            file = new FileServiceObjectAdapter(sfFile);
+                file = new FileServiceObjectAdapter(sfFile);
-            return Result.Success;
+                return Result.Success;
+            }
+            finally
+            {
+                sfFile?.Dispose();
+            }
         }
 
         protected override Result DoOpenDirectory(out IDirectory directory, U8Span path, OpenDirectoryMode mode)
@@ -143,11 +151,19 @@ namespace LibHac.Fs.Impl
             Result rc = GetPathForServiceObject(out Path sfPath, path);
             if (rc.IsFailure()) return rc;
 
-            rc = BaseFs.Target.OpenDirectory(out ReferenceCountedDisposable<IDirectorySf> sfDir, in sfPath, (uint)mode);
+            ReferenceCountedDisposable<IDirectorySf> sfDir = null;
-            if (rc.IsFailure()) return rc;
+            try
+            {
+                rc = BaseFs.Target.OpenDirectory(out sfDir, in sfPath, (uint)mode);
+                if (rc.IsFailure()) return rc;
 
-            directory = new DirectoryServiceObjectAdapter(sfDir);
+                directory = new DirectoryServiceObjectAdapter(sfDir);
-            return Result.Success;
+                return Result.Success;
+            }
+            finally
+            {
+                sfDir?.Dispose();
+            }
         }
 
         protected override Result DoCommit()
@@ -175,7 +191,7 @@ namespace LibHac.Fs.Impl
 
         public ReferenceCountedDisposable<IFileSystemSf> GetMultiCommitTarget()
         {
-            return BaseFs;
+            return BaseFs.AddReference();
         }
 
         protected override void Dispose(bool disposing)

src/LibHac/Fs/MountHelpers.cs

@@ -1,5 +1,5 @@
 using LibHac.Common;
-using static LibHac.Fs.CommonMountNames;
+using static LibHac.Fs.CommonPaths;
 
 namespace LibHac.Fs
 {

src/LibHac/Fs/QueryRangeInfo.cs

@@ -25,7 +25,7 @@ namespace LibHac.Fs
         {
             InternalKeyForSoftwareAes = 1 << 0,
             InternalKeyForHardwareAes = 1 << 1,
-            ExternalKeyForHardwareAes = 1 << 2,
+            ExternalKeyForHardwareAes = 1 << 2
         }
     }
 }

src/LibHac/Fs/ResultFs.cs

@@ -423,6 +423,8 @@ namespace LibHac.Fs
 
             /// <summary>Error code: 2002-6300; Range: 6300-6399; Inner value: 0x313802</summary>
             public static Result.Base UnsupportedOperation { [MethodImpl(MethodImplOptions.AggressiveInlining)] get => new Result.Base(ModuleFs, 6300, 6399); }
+                /// <summary>Error code: 2002-6301; Inner value: 0x313a02</summary>
+                public static Result.Base UnsupportedCommitTarget => new Result.Base(ModuleFs, 6301);
                 /// <summary>Attempted to resize a non-resizable SubStorage.<br/>Error code: 2002-6302; Inner value: 0x313c02</summary>
                 public static Result.Base UnsupportedOperationInSubStorageSetSize => new Result.Base(ModuleFs, 6302);
                 /// <summary>Attempted to resize a SubStorage that wasn't located at the end of the base storage.<br/>Error code: 2002-6303; Inner value: 0x313e02</summary>
@@ -481,14 +483,24 @@ namespace LibHac.Fs
             public static Result.Base ExternalKeyAlreadyRegistered => new Result.Base(ModuleFs, 6452);
             /// <summary>Error code: 2002-6454; Inner value: 0x326c02</summary>
             public static Result.Base WriteStateUnflushed => new Result.Base(ModuleFs, 6454);
+            /// <summary>Error code: 2002-6456; Inner value: 0x327002</summary>
+            public static Result.Base DirectoryNotClosed => new Result.Base(ModuleFs, 6456);
             /// <summary>Error code: 2002-6457; Inner value: 0x327202</summary>
             public static Result.Base WriteModeFileNotClosed => new Result.Base(ModuleFs, 6457);
+            /// <summary>Error code: 2002-6458; Inner value: 0x327402</summary>
+            public static Result.Base AllocatorAlreadyRegistered => new Result.Base(ModuleFs, 6458);
+            /// <summary>Error code: 2002-6459; Inner value: 0x327602</summary>
+            public static Result.Base DefaultAllocatorUsed => new Result.Base(ModuleFs, 6459);
             /// <summary>Error code: 2002-6461; Inner value: 0x327a02</summary>
             public static Result.Base AllocatorAlignmentViolation => new Result.Base(ModuleFs, 6461);
             /// <summary>The provided file system has already been added to the multi-commit manager.<br/>Error code: 2002-6463; Inner value: 0x327e02</summary>
             public static Result.Base MultiCommitFileSystemAlreadyAdded => new Result.Base(ModuleFs, 6463);
             /// <summary>Error code: 2002-6465; Inner value: 0x328202</summary>
             public static Result.Base UserNotExist => new Result.Base(ModuleFs, 6465);
+            /// <summary>Error code: 2002-6466; Inner value: 0x328402</summary>
+            public static Result.Base DefaultGlobalFileDataCacheEnabled => new Result.Base(ModuleFs, 6466);
+            /// <summary>Error code: 2002-6467; Inner value: 0x328602</summary>
+            public static Result.Base SaveDataRootPathUnavailable => new Result.Base(ModuleFs, 6467);
 
         /// <summary>Error code: 2002-6600; Range: 6600-6699; Inner value: 0x339002</summary>
         public static Result.Base EntryNotFound { [MethodImpl(MethodImplOptions.AggressiveInlining)] get => new Result.Base(ModuleFs, 6600, 6699); }

src/LibHac/Fs/SaveDataStructs.cs

@@ -1,7 +1,9 @@
 using System;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using LibHac.Common;
 using LibHac.Ncm;
+using LibHac.Util;
 
 namespace LibHac.Fs
 {
@@ -13,17 +15,17 @@ namespace LibHac.Fs
         [FieldOffset(0x18)] public ulong StaticSaveDataId;
         [FieldOffset(0x20)] public SaveDataType Type;
         [FieldOffset(0x21)] public SaveDataRank Rank;
-        [FieldOffset(0x22)] public short Index;
+        [FieldOffset(0x22)] public ushort Index;
 
         public SaveDataAttribute(ProgramId programId, SaveDataType type, UserId userId, ulong saveDataId) : this(
             programId, type, userId, saveDataId, 0, SaveDataRank.Primary)
         { }
 
         public SaveDataAttribute(ProgramId programId, SaveDataType type, UserId userId, ulong saveDataId,
-            short index) : this(programId, type, userId, saveDataId, index, SaveDataRank.Primary)
+            ushort index) : this(programId, type, userId, saveDataId, index, SaveDataRank.Primary)
         { }
 
-        public SaveDataAttribute(ProgramId programId, SaveDataType type, UserId userId, ulong saveDataId, short index,
+        public SaveDataAttribute(ProgramId programId, SaveDataType type, UserId userId, ulong saveDataId, ushort index,
             SaveDataRank rank)
         {
             ProgramId = programId;
@@ -34,6 +36,38 @@ namespace LibHac.Fs
             Rank = rank;
         }
 
+        public static Result Make(out SaveDataAttribute attribute, ProgramId programId, SaveDataType type,
+            UserId userId, ulong staticSaveDataId)
+        {
+            return Make(out attribute, programId, type, userId, staticSaveDataId, 0, SaveDataRank.Primary);
+        }
+
+        public static Result Make(out SaveDataAttribute attribute, ProgramId programId, SaveDataType type,
+            UserId userId, ulong staticSaveDataId, ushort index)
+        {
+            return Make(out attribute, programId, type, userId, staticSaveDataId, index, SaveDataRank.Primary);
+        }
+
+        public static Result Make(out SaveDataAttribute attribute, ProgramId programId, SaveDataType type,
+            UserId userId, ulong staticSaveDataId, ushort index, SaveDataRank rank)
+        {
+            Unsafe.SkipInit(out attribute);
+            SaveDataAttribute tempAttribute = default;
+
+            tempAttribute.ProgramId = programId;
+            tempAttribute.Type = type;
+            tempAttribute.UserId = userId;
+            tempAttribute.StaticSaveDataId = staticSaveDataId;
+            tempAttribute.Index = index;
+            tempAttribute.Rank = rank;
+
+            if (!SaveDataTypesValidity.IsValid(in tempAttribute))
+                return ResultFs.InvalidArgument.Log();
+
+            attribute = tempAttribute;
+            return Result.Success;
+        }
+
         public override readonly bool Equals(object obj)
         {
             return obj is SaveDataAttribute attribute && Equals(attribute);
@@ -85,40 +119,96 @@ namespace LibHac.Fs
         [FieldOffset(0x04)] public bool FilterByIndex;
         [FieldOffset(0x05)] public SaveDataRank Rank;
 
-        [FieldOffset(0x08)] public ProgramId ProgramId;
+        [FieldOffset(0x08)] public SaveDataAttribute Attribute;
-        [FieldOffset(0x10)] public UserId UserId;
-        [FieldOffset(0x20)] public ulong SaveDataId;
-        [FieldOffset(0x28)] public SaveDataType SaveDataType;
-        [FieldOffset(0x2A)] public short Index;
 
         public void SetProgramId(ProgramId value)
         {
             FilterByProgramId = true;
-            ProgramId = value;
+            Attribute.ProgramId = value;
         }
 
         public void SetSaveDataType(SaveDataType value)
         {
             FilterBySaveDataType = true;
-            SaveDataType = value;
+            Attribute.Type = value;
         }
 
         public void SetUserId(UserId value)
         {
             FilterByUserId = true;
-            UserId = value;
+            Attribute.UserId = value;
         }
 
         public void SetSaveDataId(ulong value)
         {
             FilterBySaveDataId = true;
-            SaveDataId = value;
+            Attribute.StaticSaveDataId = value;
         }
 
-        public void SetIndex(short value)
+        public void SetIndex(ushort value)
         {
             FilterByIndex = true;
-            Index = value;
+            Attribute.Index = value;
+        }
+
+        public static Result Make(out SaveDataFilter filter, Optional<ulong> programId, Optional<SaveDataType> saveType,
+            Optional<UserId> userId, Optional<ulong> saveDataId, Optional<ushort> index)
+        {
+            return Make(out filter, programId, saveType, userId, saveDataId, index, SaveDataRank.Primary);
+        }
+
+        public static Result Make(out SaveDataFilter filter, Optional<ulong> programId, Optional<SaveDataType> saveType,
+            Optional<UserId> userId, Optional<ulong> saveDataId, Optional<ushort> index, SaveDataRank rank)
+        {
+            Unsafe.SkipInit(out filter);
+
+            SaveDataFilter tempFilter = Make(programId, saveType, userId, saveDataId, index, rank);
+
+            if (!SaveDataTypesValidity.IsValid(in tempFilter))
+                return ResultFs.InvalidArgument.Log();
+
+            filter = tempFilter;
+            return Result.Success;
+        }
+
+        public static SaveDataFilter Make(Optional<ulong> programId, Optional<SaveDataType> saveType,
+            Optional<UserId> userId, Optional<ulong> saveDataId, Optional<ushort> index, SaveDataRank rank)
+        {
+            var filter = new SaveDataFilter();
+
+            if (programId.HasValue)
+            {
+                filter.FilterByProgramId = true;
+                filter.Attribute.ProgramId = new ProgramId(programId.Value);
+            }
+
+            if (saveType.HasValue)
+            {
+                filter.FilterBySaveDataType = true;
+                filter.Attribute.Type = saveType.Value;
+            }
+
+            if (userId.HasValue)
+            {
+                filter.FilterByUserId = true;
+                filter.Attribute.UserId = userId.Value;
+            }
+
+            if (saveDataId.HasValue)
+            {
+                filter.FilterBySaveDataId = true;
+                filter.Attribute.StaticSaveDataId = saveDataId.Value;
+            }
+
+            if (index.HasValue)
+            {
+                filter.FilterByIndex = true;
+                filter.Attribute.Index = index.Value;
+            }
+
+            filter.Rank = rank;
+
+            return filter;
         }
     }
 
@@ -130,6 +220,7 @@ namespace LibHac.Fs
         [FieldOffset(0x00)] private byte _hashStart;
 
         public Span<byte> Hash => SpanHelpers.CreateSpan(ref _hashStart, HashLength);
+        public ReadOnlySpan<byte> HashRo => SpanHelpers.CreateReadOnlySpan(in _hashStart, HashLength);
     }
 
     [StructLayout(LayoutKind.Sequential, Pack = 1)]
@@ -140,7 +231,7 @@ namespace LibHac.Fs
     }
 
     [StructLayout(LayoutKind.Explicit, Size = 0x10)]
-    public struct SaveMetaCreateInfo
+    public struct SaveDataMetaInfo
     {
         [FieldOffset(0)] public int Size;
         [FieldOffset(4)] public SaveDataMetaType Type;
@@ -151,7 +242,7 @@ namespace LibHac.Fs
     {
         [FieldOffset(0x00)] public long Size;
         [FieldOffset(0x08)] public long JournalSize;
-        [FieldOffset(0x10)] public ulong BlockSize;
+        [FieldOffset(0x10)] public long BlockSize;
         [FieldOffset(0x18)] public ulong OwnerId;
         [FieldOffset(0x20)] public SaveDataFlags Flags;
         [FieldOffset(0x24)] public SaveDataSpaceId SpaceId;
@@ -168,8 +259,66 @@ namespace LibHac.Fs
         [FieldOffset(0x20)] public ulong StaticSaveDataId;
         [FieldOffset(0x28)] public ProgramId ProgramId;
         [FieldOffset(0x30)] public long Size;
-        [FieldOffset(0x38)] public short Index;
+        [FieldOffset(0x38)] public ushort Index;
         [FieldOffset(0x3A)] public SaveDataRank Rank;
         [FieldOffset(0x3B)] public SaveDataState State;
     }
+
+    [StructLayout(LayoutKind.Explicit, Size = 0x200)]
+    public struct SaveDataExtraData
+    {
+        [FieldOffset(0x00)] public SaveDataAttribute Attribute;
+        [FieldOffset(0x40)] public ulong OwnerId;
+        [FieldOffset(0x48)] public ulong TimeStamp;
+        [FieldOffset(0x50)] public SaveDataFlags Flags;
+        [FieldOffset(0x58)] public long DataSize;
+        [FieldOffset(0x60)] public long JournalSize;
+        [FieldOffset(0x68)] public long CommitId;
+    }
+
+    internal static class SaveDataTypesValidity
+    {
+        public static bool IsValid(in SaveDataAttribute attribute)
+        {
+            return IsValid(in attribute.Type) && IsValid(in attribute.Rank);
+        }
+
+        public static bool IsValid(in SaveDataCreationInfo creationInfo)
+        {
+            return creationInfo.Size >= 0 && creationInfo.JournalSize >= 0 && creationInfo.BlockSize >= 0 &&
+                   IsValid(in creationInfo.SpaceId);
+        }
+
+        public static bool IsValid(in SaveDataMetaInfo metaInfo)
+        {
+            return IsValid(in metaInfo.Type);
+        }
+
+        public static bool IsValid(in SaveDataFilter filter)
+        {
+            return IsValid(in filter.Attribute);
+        }
+
+        public static bool IsValid(in SaveDataType type)
+        {
+            // SaveDataType.SystemBcat is excluded in this check
+            return (uint)type <= (uint)SaveDataType.Cache;
+        }
+
+        public static bool IsValid(in SaveDataRank rank)
+        {
+            return (uint)rank <= (uint)SaveDataRank.Secondary;
+        }
+
+        public static bool IsValid(in SaveDataSpaceId spaceId)
+        {
+            return (uint)spaceId <= (uint)SaveDataSpaceId.SdCache || spaceId == SaveDataSpaceId.ProperSystem ||
+                   spaceId == SaveDataSpaceId.SafeMode;
+        }
+
+        public static bool IsValid(in SaveDataMetaType metaType)
+        {
+            return (uint)metaType <= (uint)SaveDataMetaType.ExtensionContext;
+        }
+    }
 }

src/LibHac/Fs/Shim/BcatSaveData.cs

@@ -1,7 +1,8 @@
 using System;
 using LibHac.Common;
-using LibHac.Fs.Fsa;
+using LibHac.Fs.Impl;
 using LibHac.FsSrv;
+using LibHac.FsSrv.Sf;
 
 namespace LibHac.Fs.Shim
 {
@@ -43,12 +44,23 @@ namespace LibHac.Fs.Shim
 
             IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-            var attribute = new SaveDataAttribute(applicationId, SaveDataType.Bcat, UserId.Zero, 0);
+            var attribute = new SaveDataAttribute(applicationId, SaveDataType.Bcat, UserId.InvalidId, 0);
 
-            rc = fsProxy.OpenSaveDataFileSystem(out IFileSystem fileSystem, SaveDataSpaceId.User, ref attribute);
+            ReferenceCountedDisposable<IFileSystemSf> saveFs = null;
-            if (rc.IsFailure()) return rc;
 
-            return fs.Register(mountName, fileSystem);
+            try
+            {
+                rc = fsProxy.OpenSaveDataFileSystem(out saveFs, SaveDataSpaceId.User, in attribute);
+                if (rc.IsFailure()) return rc;
+
+                var fileSystemAdapter = new FileSystemServiceObjectAdapter(saveFs);
+
+                return fs.Register(mountName, fileSystemAdapter);
+            }
+            finally
+            {
+                saveFs?.Dispose();
+            }
         }
     }
 }

src/LibHac/Fs/Shim/Bis.cs

@@ -6,7 +6,7 @@ using LibHac.FsSrv;
 using LibHac.FsSrv.Sf;
 using LibHac.FsSystem;
 using LibHac.Util;
-using static LibHac.Fs.CommonMountNames;
+using static LibHac.Fs.CommonPaths;
 
 namespace LibHac.Fs.Shim
 {

src/LibHac/Fs/Shim/Content.cs

@@ -83,7 +83,7 @@ namespace LibHac.Fs.Shim
             ContentType.Control => FileSystemProxyType.Control,
             ContentType.Manual => FileSystemProxyType.Manual,
             ContentType.Data => FileSystemProxyType.Data,
-            _ => throw new ArgumentOutOfRangeException(nameof(type), type, null),
+            _ => throw new ArgumentOutOfRangeException(nameof(type), type, null)
         };
     }
 }

src/LibHac/Fs/Shim/ContentStorage.cs

@@ -39,11 +39,11 @@ namespace LibHac.Fs.Shim
             switch (storageId)
             {
                 case ContentStorageId.System:
-                    return CommonMountNames.ContentStorageSystemMountName;
+                    return CommonPaths.ContentStorageSystemMountName;
                 case ContentStorageId.User:
-                    return CommonMountNames.ContentStorageUserMountName;
+                    return CommonPaths.ContentStorageUserMountName;
                 case ContentStorageId.SdCard:
-                    return CommonMountNames.ContentStorageSdCardMountName;
+                    return CommonPaths.ContentStorageSdCardMountName;
                 default:
                     throw new ArgumentOutOfRangeException(nameof(storageId), storageId, null);
             }

src/LibHac/Fs/Shim/GameCard.cs

@@ -76,7 +76,7 @@ namespace LibHac.Fs.Shim
             {
                 char letter = GetGameCardMountNameSuffix(PartitionId);
 
-                string mountName = $"{CommonMountNames.GameCardFileSystemMountName}{letter}{Handle.Value:x8}";
+                string mountName = $"{CommonPaths.GameCardFileSystemMountName}{letter}{Handle.Value:x8}";
                 new U8Span(mountName).Value.CopyTo(nameBuffer);
 
                 return Result.Success;

src/LibHac/Fs/Shim/Host.cs

@@ -6,7 +6,7 @@ using LibHac.Fs.Fsa;
 using LibHac.FsSrv;
 using LibHac.FsSystem;
 using LibHac.Util;
-using static LibHac.Fs.CommonMountNames;
+using static LibHac.Fs.CommonPaths;
 
 namespace LibHac.Fs.Shim
 {

src/LibHac/Fs/Shim/ProgramIndexMapInfo.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Runtime.InteropServices;
 using LibHac.FsSrv;
+using LibHac.Sf;
 
 namespace LibHac.Fs.Shim
 {
@@ -21,7 +22,7 @@ namespace LibHac.Fs.Shim
 
             IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-            ReadOnlySpan<byte> mapInfoBuffer = MemoryMarshal.Cast<ProgramIndexMapInfo, byte>(mapInfo);
+            var mapInfoBuffer = new InBuffer(MemoryMarshal.Cast<ProgramIndexMapInfo, byte>(mapInfo));
 
             return fsProxy.RegisterProgramIndexMapInfo(mapInfoBuffer, mapInfo.Length);
         }

src/LibHac/Fs/Shim/SaveData.cs

@@ -1,7 +1,8 @@
 using System;
 using LibHac.Common;
-using LibHac.Fs.Fsa;
+using LibHac.Fs.Impl;
 using LibHac.FsSrv;
+using LibHac.FsSrv.Sf;
 using LibHac.Ncm;
 
 namespace LibHac.Fs.Shim
@@ -115,14 +116,14 @@ namespace LibHac.Fs.Shim
             if (fs.IsEnabledAccessLog(AccessLogTarget.Application))
             {
                 TimeSpan startTime = fs.Time.GetCurrent();
-                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, default, default, SaveDataType.Cache, false, (short)index);
+                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, default, default, SaveDataType.Cache, false, (ushort)index);
                 TimeSpan endTime = fs.Time.GetCurrent();
 
                 fs.OutputAccessLog(rc, startTime, endTime, $", name: \"{mountName.ToString()}\", index: {index}");
             }
             else
             {
-                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, default, default, SaveDataType.Cache, false, (short)index);
+                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, default, default, SaveDataType.Cache, false, (ushort)index);
             }
 
             if (rc.IsSuccess() && fs.IsEnabledAccessLog(AccessLogTarget.Application))
@@ -165,14 +166,14 @@ namespace LibHac.Fs.Shim
             if (fs.IsEnabledAccessLog(AccessLogTarget.System))
             {
                 TimeSpan startTime = fs.Time.GetCurrent();
-                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, applicationId, default, SaveDataType.Cache, false, (short)index);
+                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, applicationId, default, SaveDataType.Cache, false, (ushort)index);
                 TimeSpan endTime = fs.Time.GetCurrent();
 
                 fs.OutputAccessLog(rc, startTime, endTime, $", name: \"{mountName.ToString()}\", applicationid: 0x{applicationId}, index: {index}");
             }
             else
             {
-                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, applicationId, default, SaveDataType.Cache, false, (short)index);
+                rc = MountSaveDataImpl(fs, mountName, SaveDataSpaceId.User, applicationId, default, SaveDataType.Cache, false, (ushort)index);
             }
 
             if (rc.IsSuccess() && fs.IsEnabledAccessLog(AccessLogTarget.System))
@@ -184,7 +185,7 @@ namespace LibHac.Fs.Shim
         }
 
         private static Result MountSaveDataImpl(this FileSystemClient fs, U8Span mountName, SaveDataSpaceId spaceId,
-            ProgramId programId, UserId userId, SaveDataType type, bool openReadOnly, short index)
+            ProgramId programId, UserId userId, SaveDataType type, bool openReadOnly, ushort index)
         {
             Result rc = MountHelpers.CheckMountName(mountName);
             if (rc.IsFailure()) return rc;
@@ -193,20 +194,29 @@ namespace LibHac.Fs.Shim
 
             var attribute = new SaveDataAttribute(programId, type, userId, 0, index);
 
-            IFileSystem saveFs;
+            ReferenceCountedDisposable<IFileSystemSf> saveFs = null;
 
-            if (openReadOnly)
+            try
             {
-                rc = fsProxy.OpenReadOnlySaveDataFileSystem(out saveFs, spaceId, ref attribute);
+                if (openReadOnly)
+                {
+                    rc = fsProxy.OpenReadOnlySaveDataFileSystem(out saveFs, spaceId, in attribute);
+                }
+                else
+                {
+                    rc = fsProxy.OpenSaveDataFileSystem(out saveFs, spaceId, in attribute);
+                }
+
+                if (rc.IsFailure()) return rc;
+
+                var fileSystemAdapter = new FileSystemServiceObjectAdapter(saveFs);
+
+                return fs.Register(mountName, fileSystemAdapter, fileSystemAdapter, null);
             }
-            else
+            finally
             {
-                rc = fsProxy.OpenSaveDataFileSystem(out saveFs, spaceId, ref attribute);
+                saveFs?.Dispose();
             }
-
-            if (rc.IsFailure()) return rc;
-
-            return fs.Register(mountName, saveFs);
         }
     }
 }

src/LibHac/Fs/Shim/SaveDataManagement.cs

@@ -1,9 +1,10 @@
 using System;
 using System.Runtime.InteropServices;
-using LibHac.Common;
 using LibHac.Diag;
 using LibHac.FsSrv;
+using LibHac.FsSrv.Sf;
 using LibHac.Ncm;
+using LibHac.Sf;
 
 namespace LibHac.Fs.Shim
 {
@@ -29,13 +30,13 @@ namespace LibHac.Fs.Shim
                         SpaceId = SaveDataSpaceId.User
                     };
 
-                    var metaInfo = new SaveMetaCreateInfo
+                    var metaInfo = new SaveDataMetaInfo
                     {
                         Type = SaveDataMetaType.Thumbnail,
                         Size = 0x40060
                     };
 
-                    return fsProxy.CreateSaveDataFileSystem(ref attribute, ref createInfo, ref metaInfo);
+                    return fsProxy.CreateSaveDataFileSystem(in attribute, in createInfo, in metaInfo);
                 },
                 () =>
                     $", applicationid: 0x{applicationId.Value:X}, userid: 0x{userId}, save_data_owner_id: 0x{ownerId:X}, save_data_size: {size}, save_data_journal_size: {journalSize}, save_data_flags: 0x{(int)flags:X8}");
@@ -61,14 +62,14 @@ namespace LibHac.Fs.Shim
                         SpaceId = SaveDataSpaceId.User
                     };
 
-                    var metaInfo = new SaveMetaCreateInfo
+                    var metaInfo = new SaveDataMetaInfo
                     {
                         Type = SaveDataMetaType.Thumbnail,
                         Size = 0x40060
                     };
 
-                    return fsProxy.CreateSaveDataFileSystemWithHashSalt(ref attribute, ref createInfo, ref metaInfo,
+                    return fsProxy.CreateSaveDataFileSystemWithHashSalt(in attribute, in createInfo, in metaInfo,
-                        ref hashSalt);
+                        in hashSalt);
                 },
                 () =>
                     $", applicationid: 0x{applicationId.Value:X}, userid: 0x{userId}, save_data_owner_id: 0x{ownerId:X}, save_data_size: {size}, save_data_journal_size: {journalSize}, save_data_flags: 0x{(int)flags:X8}");
@@ -81,7 +82,7 @@ namespace LibHac.Fs.Shim
                 {
                     IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Bcat, UserId.Zero, 0);
+                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Bcat, UserId.InvalidId, 0);
 
                     var createInfo = new SaveDataCreationInfo
                     {
@@ -93,9 +94,9 @@ namespace LibHac.Fs.Shim
                         SpaceId = SaveDataSpaceId.User
                     };
 
-                    var metaInfo = new SaveMetaCreateInfo();
+                    var metaInfo = new SaveDataMetaInfo();
 
-                    return fsProxy.CreateSaveDataFileSystem(ref attribute, ref createInfo, ref metaInfo);
+                    return fsProxy.CreateSaveDataFileSystem(in attribute, in createInfo, in metaInfo);
                 },
                 () => $", applicationid: 0x{applicationId.Value:X}, save_data_size: {size}");
         }
@@ -108,7 +109,7 @@ namespace LibHac.Fs.Shim
                 {
                     IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Device, UserId.Zero, 0);
+                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Device, UserId.InvalidId, 0);
 
                     var createInfo = new SaveDataCreationInfo
                     {
@@ -120,9 +121,9 @@ namespace LibHac.Fs.Shim
                         SpaceId = SaveDataSpaceId.User
                     };
 
-                    var metaInfo = new SaveMetaCreateInfo();
+                    var metaInfo = new SaveDataMetaInfo();
 
-                    return fsProxy.CreateSaveDataFileSystem(ref attribute, ref createInfo, ref metaInfo);
+                    return fsProxy.CreateSaveDataFileSystem(in attribute, in createInfo, in metaInfo);
                 },
                 () => $", applicationid: 0x{applicationId.Value:X}, save_data_owner_id: 0x{ownerId:X}, save_data_size: {size}, save_data_journal_size: {journalSize}, save_data_flags: 0x{(int)flags:X8}");
         }
@@ -134,7 +135,7 @@ namespace LibHac.Fs.Shim
                 {
                     IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Temporary, UserId.Zero, 0);
+                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Temporary, UserId.InvalidId, 0);
 
                     var createInfo = new SaveDataCreationInfo
                     {
@@ -145,22 +146,22 @@ namespace LibHac.Fs.Shim
                         SpaceId = SaveDataSpaceId.Temporary
                     };
 
-                    var metaInfo = new SaveMetaCreateInfo();
+                    var metaInfo = new SaveDataMetaInfo();
 
-                    return fsProxy.CreateSaveDataFileSystem(ref attribute, ref createInfo, ref metaInfo);
+                    return fsProxy.CreateSaveDataFileSystem(in attribute, in createInfo, in metaInfo);
                 },
                 () => $", applicationid: 0x{applicationId.Value:X}, save_data_owner_id: 0x{ownerId:X}, save_data_size: {size}, save_data_flags: 0x{(int)flags:X8}");
         }
 
         public static Result CreateCacheStorage(this FileSystemClient fs, Ncm.ApplicationId applicationId,
-            SaveDataSpaceId spaceId, ulong ownerId, short index, long size, long journalSize, SaveDataFlags flags)
+            SaveDataSpaceId spaceId, ulong ownerId, ushort index, long size, long journalSize, SaveDataFlags flags)
         {
             return fs.RunOperationWithAccessLog(AccessLogTarget.System,
                 () =>
                 {
                     IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Cache, UserId.Zero, 0, index);
+                    var attribute = new SaveDataAttribute(applicationId, SaveDataType.Cache, UserId.InvalidId, 0, index);
 
                     var creationInfo = new SaveDataCreationInfo
                     {
@@ -172,9 +173,9 @@ namespace LibHac.Fs.Shim
                         SpaceId = spaceId
                     };
 
-                    var metaInfo = new SaveMetaCreateInfo();
+                    var metaInfo = new SaveDataMetaInfo();
 
-                    return fsProxy.CreateSaveDataFileSystem(ref attribute, ref creationInfo, ref metaInfo);
+                    return fsProxy.CreateSaveDataFileSystem(in attribute, in creationInfo, in metaInfo);
                 },
                 () => $", applicationid: 0x{applicationId.Value:X}, savedataspaceid: {spaceId}, save_data_owner_id: 0x{ownerId:X}, save_data_size: {size}, save_data_journal_size: {journalSize}, save_data_flags: 0x{(int)flags:X8}");
         }
@@ -231,19 +232,19 @@ namespace LibHac.Fs.Shim
         public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, ulong ownerId, long size,
             long journalSize, SaveDataFlags flags)
         {
-            return CreateSystemSaveData(fs, SaveDataSpaceId.System, saveDataId, UserId.Zero, ownerId, size, journalSize, flags);
+            return CreateSystemSaveData(fs, SaveDataSpaceId.System, saveDataId, UserId.InvalidId, ownerId, size, journalSize, flags);
         }
 
         public static Result CreateSystemSaveData(this FileSystemClient fs, ulong saveDataId, long size,
             long journalSize, SaveDataFlags flags)
         {
-            return CreateSystemSaveData(fs, SaveDataSpaceId.System, saveDataId, UserId.Zero, 0, size, journalSize, flags);
+            return CreateSystemSaveData(fs, SaveDataSpaceId.System, saveDataId, UserId.InvalidId, 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, UserId.Zero, ownerId, size, journalSize, flags);
+            return CreateSystemSaveData(fs, spaceId, saveDataId, UserId.InvalidId, ownerId, size, journalSize, flags);
         }
 
         public static Result DeleteSaveData(this FileSystemClient fs, ulong saveDataId)
@@ -283,8 +284,8 @@ namespace LibHac.Fs.Shim
 
                     tempInfo = new SaveDataInfo();
 
-                    Result rc = fsProxy.FindSaveDataWithFilter(out long count, SpanHelpers.AsByteSpan(ref tempInfo),
+                    Result rc = fsProxy.FindSaveDataWithFilter(out long count, OutBuffer.FromStruct(ref tempInfo),
-                        spaceId, ref tempFilter);
+                        spaceId, in tempFilter);
                     if (rc.IsFailure()) return rc;
 
                     if (count == 0)
@@ -329,49 +330,64 @@ namespace LibHac.Fs.Shim
         {
             var tempIterator = new SaveDataIterator();
 
-            Result result = fs.RunOperationWithAccessLog(AccessLogTarget.System,
+            try
-                () =>
+            {
-                {
+                Result result = fs.RunOperationWithAccessLog(AccessLogTarget.System,
-                    IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
+                    () =>
+                    {
+                        IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-                    Result rc = fsProxy.OpenSaveDataInfoReaderBySaveDataSpaceId(
+                        Result rc = fsProxy.OpenSaveDataInfoReaderBySaveDataSpaceId(
-                        out ReferenceCountedDisposable<ISaveDataInfoReader> reader, spaceId);
+                            out ReferenceCountedDisposable<ISaveDataInfoReader> reader, spaceId);
-                    if (rc.IsFailure()) return rc;
+                        if (rc.IsFailure()) return rc;
 
-                    tempIterator = new SaveDataIterator(fs, reader);
+                        tempIterator = new SaveDataIterator(fs, reader);
 
-                    return Result.Success;
+                        return Result.Success;
-                },
+                    },
-                () => $", savedataspaceid: {spaceId}");
+                    () => $", savedataspaceid: {spaceId}");
 
-            iterator = result.IsSuccess() ? tempIterator : default;
+                iterator = result.IsSuccess() ? tempIterator : default;
+                tempIterator = default;
 
-            return result;
+                return result;
+            }
+            finally
+            {
+                tempIterator.Dispose();
+            }
         }
 
         public static Result OpenSaveDataIterator(this FileSystemClient fs, out SaveDataIterator iterator, SaveDataSpaceId spaceId, ref SaveDataFilter filter)
         {
+            ReferenceCountedDisposable<ISaveDataInfoReader> reader = null;
             var tempIterator = new SaveDataIterator();
             SaveDataFilter tempFilter = filter;
 
-            Result result = fs.RunOperationWithAccessLog(AccessLogTarget.System,
+            try
-                () =>
+            {
-                {
+                Result result = fs.RunOperationWithAccessLog(AccessLogTarget.System,
-                    IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
+                    () =>
+                    {
+                        IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
 
-                    Result rc = fsProxy.OpenSaveDataInfoReaderWithFilter(
+                        Result rc = fsProxy.OpenSaveDataInfoReaderWithFilter(out reader, spaceId, in tempFilter);
-                        out ReferenceCountedDisposable<ISaveDataInfoReader> reader, spaceId, ref tempFilter);
+                        if (rc.IsFailure()) return rc;
-                    if (rc.IsFailure()) return rc;
 
-                    tempIterator = new SaveDataIterator(fs, reader);
+                        tempIterator = new SaveDataIterator(fs, reader);
 
-                    return Result.Success;
+                        return Result.Success;
-                },
+                    },
-                () => $", savedataspaceid: {spaceId}");
+                    () => $", savedataspaceid: {spaceId}");
 
-            iterator = result.IsSuccess() ? tempIterator : default;
+                iterator = result.IsSuccess() ? tempIterator : default;
 
-            return result;
+                return result;
+            }
+            finally
+            {
+                reader?.Dispose();
+            }
         }
 
         public static void DisableAutoSaveDataCreation(this FileSystemClient fsClient)
@@ -395,14 +411,14 @@ namespace LibHac.Fs.Shim
         internal SaveDataIterator(FileSystemClient fsClient, ReferenceCountedDisposable<ISaveDataInfoReader> reader)
         {
             FsClient = fsClient;
-            Reader = reader;
+            Reader = reader.AddReference();
         }
 
         public Result ReadSaveDataInfo(out long readCount, Span<SaveDataInfo> buffer)
         {
             Result rc;
 
-            Span<byte> byteBuffer = MemoryMarshal.Cast<SaveDataInfo, byte>(buffer);
+            var byteBuffer = new OutBuffer(MemoryMarshal.Cast<SaveDataInfo, byte>(buffer));
 
             if (FsClient.IsEnabledAccessLog(AccessLogTarget.System))
             {

src/LibHac/Fs/Shim/SystemSaveData.cs

@@ -1,15 +1,17 @@
 using LibHac.Common;
-using LibHac.Fs.Fsa;
+using LibHac.Fs.Impl;
 using LibHac.FsSrv;
+using LibHac.FsSrv.Sf;
 using LibHac.Ncm;
 
 namespace LibHac.Fs.Shim
 {
     public static class SystemSaveData
     {
-        public static Result MountSystemSaveData(this FileSystemClient fs, U8Span mountName, SaveDataSpaceId spaceId, ulong saveDataId)
+        public static Result MountSystemSaveData(this FileSystemClient fs, U8Span mountName, SaveDataSpaceId spaceId,
+            ulong saveDataId)
         {
-            return MountSystemSaveData(fs, mountName, spaceId, saveDataId, UserId.Zero);
+            return MountSystemSaveData(fs, mountName, spaceId, saveDataId, UserId.InvalidId);
         }
 
         public static Result MountSystemSaveData(this FileSystemClient fs, U8Span mountName,
@@ -22,10 +24,20 @@ namespace LibHac.Fs.Shim
 
             var attribute = new SaveDataAttribute(ProgramId.InvalidId, SaveDataType.System, userId, saveDataId);
 
-            rc = fsProxy.OpenSaveDataFileSystemBySystemSaveDataId(out IFileSystem fileSystem, spaceId, ref attribute);
+            ReferenceCountedDisposable<IFileSystemSf> saveFs = null;
-            if (rc.IsFailure()) return rc;
 
-            return fs.Register(mountName, fileSystem);
+            try
+            {
+                rc = fsProxy.OpenSaveDataFileSystemBySystemSaveDataId(out saveFs, spaceId, in attribute);
+                if (rc.IsFailure()) return rc;
+
+                var fileSystemAdapter = new FileSystemServiceObjectAdapter(saveFs);
+                return fs.Register(mountName, fileSystemAdapter);
+            }
+            finally
+            {
+                saveFs?.Dispose();
+            }
         }
     }
 }

src/LibHac/Fs/Shim/UserFileSystem.cs

@@ -0,0 +1,52 @@
+using System;
+using LibHac.Common;
+using LibHac.Fs.Accessors;
+using LibHac.FsSrv.Sf;
+
+namespace LibHac.Fs.Shim
+{
+    public static class UserFileSystem
+    {
+        public static Result Commit(this FileSystemClient fs, ReadOnlySpan<U8String> mountNames)
+        {
+            // Todo: Add access log
+
+            if (mountNames.Length > 10)
+                return ResultFs.InvalidCommitNameCount.Log();
+
+            if (mountNames.Length == 0)
+                return Result.Success;
+
+            ReferenceCountedDisposable<IMultiCommitManager> commitManager = null;
+            ReferenceCountedDisposable<IFileSystemSf> fileSystem = null;
+            try
+            {
+                Result rc = fs.GetFileSystemProxyServiceObject().OpenMultiCommitManager(out commitManager);
+                if (rc.IsFailure()) return rc;
+
+                for (int i = 0; i < mountNames.Length; i++)
+                {
+                    rc = fs.MountTable.Find(mountNames[i].ToString(), out FileSystemAccessor accessor);
+                    if (rc.IsFailure()) return rc;
+
+                    fileSystem = accessor.GetMultiCommitTarget();
+                    if (fileSystem is null)
+                        return ResultFs.UnsupportedCommitTarget.Log();
+
+                    rc = commitManager.Target.Add(fileSystem);
+                    if (rc.IsFailure()) return rc;
+                }
+
+                rc = commitManager.Target.Commit();
+                if (rc.IsFailure()) return rc;
+
+                return Result.Success;
+            }
+            finally
+            {
+                commitManager?.Dispose();
+                fileSystem?.Dispose();
+            }
+        }
+    }
+}

src/LibHac/Fs/UserId.cs

@@ -9,7 +9,7 @@ namespace LibHac.Fs
     [StructLayout(LayoutKind.Sequential, Size = 0x10)]
     public struct UserId : IEquatable<UserId>, IComparable<UserId>, IComparable
     {
-        public static UserId Zero => default;
+        public static UserId InvalidId => default;
 
         public readonly Id128 Id;
 

src/LibHac/FsSrv/BaseFileSystemService.cs

@@ -60,7 +60,7 @@ namespace LibHac.FsSrv
                 if (rc.IsFailure()) return rc;
 
                 // Create an SF adapter for the file system
-                fileSystem = FileSystemInterfaceAdapter.CreateSharedSfFileSystem(ref fs);
+                fileSystem = FileSystemInterfaceAdapter.CreateShared(ref fs);
 
                 return Result.Success;
             }
@@ -117,7 +117,7 @@ namespace LibHac.FsSrv
                 if (rc.IsFailure()) return rc;
 
                 // Create an SF adapter for the file system
-                fileSystem = FileSystemInterfaceAdapter.CreateSharedSfFileSystem(ref fs);
+                fileSystem = FileSystemInterfaceAdapter.CreateShared(ref fs);
 
                 return Result.Success;
             }
@@ -147,7 +147,7 @@ namespace LibHac.FsSrv
                 if (rc.IsFailure()) return rc;
 
                 // Create an SF adapter for the file system
-                fileSystem = FileSystemInterfaceAdapter.CreateSharedSfFileSystem(ref fs);
+                fileSystem = FileSystemInterfaceAdapter.CreateShared(ref fs);
 
                 return Result.Success;
             }
@@ -220,7 +220,7 @@ namespace LibHac.FsSrv
                 if (rc.IsFailure()) return rc;
 
                 // Create an SF adapter for the file system
-                fileSystem = FileSystemInterfaceAdapter.CreateSharedSfFileSystem(ref fs);
+                fileSystem = FileSystemInterfaceAdapter.CreateShared(ref fs);
 
                 return Result.Success;
             }

src/LibHac/FsSrv/BaseFileSystemServiceImpl.cs

@@ -40,7 +40,14 @@ namespace LibHac.FsSrv
             throw new NotImplementedException();
         }
 
-        public Result OpenBisFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem, U8Span rootPath, BisPartitionId partitionId)
+        public Result OpenBisFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem, U8Span rootPath,
+            BisPartitionId partitionId)
+        {
+            return OpenBisFileSystem(out fileSystem, rootPath, partitionId, false);
+        }
+
+        public Result OpenBisFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem, U8Span rootPath,
+            BisPartitionId partitionId, bool caseSensitive)
         {
             fileSystem = default;
 
@@ -85,12 +92,12 @@ namespace LibHac.FsSrv
             return OpenSdCardProxyFileSystem(out fileSystem, false);
         }
 
-        public Result OpenSdCardProxyFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem, bool isCaseSensitive)
+        public Result OpenSdCardProxyFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem, bool openCaseSensitive)
         {
             fileSystem = default;
 
             // Todo: Shared
-            Result rc = _config.SdCardFileSystemCreator.Create(out IFileSystem fs, isCaseSensitive);
+            Result rc = _config.SdCardFileSystemCreator.Create(out IFileSystem fs, openCaseSensitive);
             if (rc.IsFailure()) return rc;
 
             fileSystem = new ReferenceCountedDisposable<IFileSystem>(fs);

src/LibHac/FsSrv/Creators/EmulatedBisFileSystemCreator.cs

@@ -87,7 +87,9 @@ namespace LibHac.FsSrv.Creators
             return Util.CreateSubFileSystemImpl(out fileSystem, subFileSystem, rootPath);
         }
 
-        public Result Create(out ReferenceCountedDisposable<IFileSystem> fileSystem, U8Span rootPath, BisPartitionId partitionId)
+        // Todo: Make case sensitive
+        public Result Create(out ReferenceCountedDisposable<IFileSystem> fileSystem, U8Span rootPath,
+            BisPartitionId partitionId, bool caseSensitive)
         {
             fileSystem = default;
 
@@ -107,21 +109,28 @@ namespace LibHac.FsSrv.Creators
 
             var partitionPath = GetPartitionPath(partitionId).ToU8String();
 
-            // Todo: Store shared file systems
+            ReferenceCountedDisposable<IFileSystem> partitionFileSystem = null;
-            using var sharedRootFs = new ReferenceCountedDisposable<IFileSystem>(Config.RootFileSystem);
+            try
-
-            Result rc = Utility.WrapSubDirectory(out ReferenceCountedDisposable<IFileSystem> partitionFileSystem,
-                sharedRootFs, partitionPath, true);
-
-            if (rc.IsFailure()) return rc;
-
-            if (rootPath.IsEmpty())
             {
-                fileSystem = partitionFileSystem.AddReference();
+                // Todo: Store shared file systems
-                return Result.Success;
+                using var sharedRootFs = new ReferenceCountedDisposable<IFileSystem>(Config.RootFileSystem);
-            }
 
-            return Utility.CreateSubDirectoryFileSystem(out fileSystem, partitionFileSystem, rootPath);
+                Result rc = Utility.WrapSubDirectory(out partitionFileSystem, sharedRootFs, partitionPath, true);
+
+                if (rc.IsFailure()) return rc;
+
+                if (rootPath.IsEmpty())
+                {
+                    Shared.Move(out fileSystem, ref partitionFileSystem);
+                    return Result.Success;
+                }
+
+                return Utility.CreateSubDirectoryFileSystem(out fileSystem, partitionFileSystem, rootPath);
+            }
+            finally
+            {
+                partitionFileSystem?.Dispose();
+            }
         }
 
         public Result CreateFatFileSystem(out IFileSystem fileSystem, BisPartitionId partitionId)

src/LibHac/FsSrv/Creators/EncryptedFileSystemCreator.cs

@@ -48,7 +48,7 @@ namespace LibHac.FsSrv.Creators
             KeySet.SetSdSeed(encryptionSeed.Value);
 
             // Todo: pass ReferenceCountedDisposable to AesXtsFileSystem
-            var fs = new AesXtsFileSystem(baseFileSystem.AddReference().Target, KeySet.SdCardEncryptionKeys[(int)keyId].DataRo.ToArray(), 0x4000);
+            var fs = new AesXtsFileSystem(baseFileSystem, KeySet.SdCardEncryptionKeys[(int)keyId].DataRo.ToArray(), 0x4000);
             encryptedFileSystem = new ReferenceCountedDisposable<IFileSystem>(fs);
 
             return Result.Success;

src/LibHac/FsSrv/Creators/IBuiltInStorageFileSystemCreator.cs

@@ -8,7 +8,7 @@ namespace LibHac.FsSrv.Creators
     {
         // Todo: Remove raw IFileSystem overload
         Result Create(out IFileSystem fileSystem, string rootPath, BisPartitionId partitionId);
-        Result Create(out ReferenceCountedDisposable<IFileSystem> fileSystem, U8Span rootPath, BisPartitionId partitionId);
+        Result Create(out ReferenceCountedDisposable<IFileSystem> fileSystem, U8Span rootPath, BisPartitionId partitionId, bool caseSensitive);
         Result CreateFatFileSystem(out IFileSystem fileSystem, BisPartitionId partitionId);
         Result SetBisRootForHost(BisPartitionId partitionId, string rootPath);
     }

src/LibHac/FsSrv/Creators/ISaveDataFileSystemCreator.cs

@@ -2,7 +2,7 @@
 using LibHac.Common;
 using LibHac.Fs;
 using LibHac.Fs.Fsa;
-using LibHac.FsSystem.Save;
+using LibHac.FsSystem;
 
 namespace LibHac.FsSrv.Creators
 {
@@ -10,9 +10,10 @@ namespace LibHac.FsSrv.Creators
     {
         Result CreateFile(out IFile file, IFileSystem sourceFileSystem, ulong saveDataId, OpenMode openMode);
 
-        Result Create(out IFileSystem fileSystem, out ISaveDataExtraDataAccessor extraDataAccessor,
+        Result Create(out IFileSystem fileSystem,
-            IFileSystem sourceFileSystem, ulong saveDataId, bool allowDirectorySaveData, bool useDeviceUniqueMac,
+            out ReferenceCountedDisposable<ISaveDataExtraDataAccessor> extraDataAccessor, IFileSystem sourceFileSystem,
-            SaveDataType type, ITimeStampGenerator timeStampGenerator);
+            ulong saveDataId, bool allowDirectorySaveData, bool useDeviceUniqueMac, SaveDataType type,
+            ITimeStampGenerator timeStampGenerator);
 
         void SetSdCardEncryptionSeed(ReadOnlySpan<byte> seed);
     }

src/LibHac/FsSrv/Creators/ITargetManagerFileSystemCreator.cs

@@ -8,6 +8,6 @@ namespace LibHac.FsSrv.Creators
         // Todo: Remove raw IFilesystem function
         Result Create(out IFileSystem fileSystem, bool openCaseSensitive);
         Result Create(out ReferenceCountedDisposable<IFileSystem> fileSystem, bool openCaseSensitive);
-        Result GetCaseSensitivePath(out bool isSuccess, Span<byte> path);
+        Result NormalizeCaseOfPath(out bool isSupported, Span<byte> path);
     }
 }

src/LibHac/FsSrv/Creators/SaveDataFileSystemCreator.cs

@@ -22,9 +22,10 @@ namespace LibHac.FsSrv.Creators
             throw new NotImplementedException();
         }
 
-        public Result Create(out IFileSystem fileSystem, out ISaveDataExtraDataAccessor extraDataAccessor,
+        public Result Create(out IFileSystem fileSystem,
-            IFileSystem sourceFileSystem, ulong saveDataId, bool allowDirectorySaveData, bool useDeviceUniqueMac,
+            out ReferenceCountedDisposable<ISaveDataExtraDataAccessor> extraDataAccessor, IFileSystem sourceFileSystem,
-            SaveDataType type, ITimeStampGenerator timeStampGenerator)
+            ulong saveDataId, bool allowDirectorySaveData, bool useDeviceUniqueMac, SaveDataType type,
+            ITimeStampGenerator timeStampGenerator)
         {
             fileSystem = default;
             extraDataAccessor = default;
@@ -42,13 +43,15 @@ namespace LibHac.FsSrv.Creators
                 case DirectoryEntryType.Directory:
                     if (!allowDirectorySaveData) return ResultFs.InvalidSaveDataEntryType.Log();
 
-                    rc = SubdirectoryFileSystem.CreateNew(out SubdirectoryFileSystem subDirFs, sourceFileSystem, saveDataPath);
+                    rc = SubdirectoryFileSystem.CreateNew(out SubdirectoryFileSystem subDirFs, sourceFileSystem,
+                        saveDataPath);
                     if (rc.IsFailure()) return rc;
 
                     bool isPersistentSaveData = type != SaveDataType.Temporary;
                     bool isUserSaveData = type == SaveDataType.Account || type == SaveDataType.Device;
 
-                    rc = DirectorySaveDataFileSystem.CreateNew(out DirectorySaveDataFileSystem saveFs, subDirFs, isPersistentSaveData, isUserSaveData);
+                    rc = DirectorySaveDataFileSystem.CreateNew(out DirectorySaveDataFileSystem saveFs, subDirFs,
+                        isPersistentSaveData, isUserSaveData);
                     if (rc.IsFailure()) return rc;
 
                     fileSystem = saveFs;
@@ -62,7 +65,8 @@ namespace LibHac.FsSrv.Creators
                     if (rc.IsFailure()) return rc;
 
                     var saveDataStorage = new DisposingFileStorage(saveDataFile);
-                    fileSystem = new SaveDataFileSystem(KeySet, saveDataStorage, IntegrityCheckLevel.ErrorOnInvalid, false);
+                    fileSystem = new SaveDataFileSystem(KeySet, saveDataStorage, IntegrityCheckLevel.ErrorOnInvalid,
+                        false);
 
                     // Todo: ISaveDataExtraDataAccessor
 

src/LibHac/FsSrv/Creators/TargetManagerFileSystemCreator.cs

@@ -15,7 +15,7 @@ namespace LibHac.FsSrv.Creators
             throw new NotImplementedException();
         }
 
-        public Result GetCaseSensitivePath(out bool isSuccess, Span<byte> path)
+        public Result NormalizeCaseOfPath(out bool isSupported, Span<byte> path)
         {
             throw new NotImplementedException();
         }

src/LibHac/FsSrv/Delegates.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace LibHac.FsSrv
+{
+    public delegate Result RandomDataGenerator(Span<byte> buffer);
+
+    public delegate Result SaveTransferAesKeyGenerator(Span<byte> key,
+        SaveDataTransferCryptoConfiguration.KeyIndex index, ReadOnlySpan<byte> keySource, int keyGeneration);
+
+    public delegate Result SaveTransferCmacGenerator(Span<byte> mac, ReadOnlySpan<byte> data,
+        SaveDataTransferCryptoConfiguration.KeyIndex index, int keyGeneration);
+}

src/LibHac/FsSrv/FileSystemProxyConfiguration.cs

@@ -7,6 +7,7 @@ namespace LibHac.FsSrv
         public FileSystemCreators FsCreatorInterfaces { get; set; }
         public BaseFileSystemServiceImpl BaseFileSystemService { get; set; }
         public NcaFileSystemServiceImpl NcaFileSystemService { get; set; }
+        public SaveDataFileSystemServiceImpl SaveDataFileSystemService { get; set; }
         public ProgramRegistryServiceImpl ProgramRegistryService { get; set; }
     }
 }

src/LibHac/FsSrv/FileSystemProxyCoreImpl.cs

@@ -3,7 +3,6 @@ using LibHac.Common;
 using LibHac.Fs;
 using LibHac.Fs.Fsa;
 using LibHac.Fs.Shim;
-using LibHac.FsSystem;
 using LibHac.FsSrv.Creators;
 
 namespace LibHac.FsSrv
@@ -21,7 +20,6 @@ namespace LibHac.FsSrv
         private const string NintendoDirectoryName = "Nintendo";
 
         private GlobalAccessLogMode LogMode { get; set; }
-        public bool IsSdCardAccessible { get; set; }
 
         internal ISaveDataIndexerManager SaveDataIndexerManager { get; private set; }
 
@@ -32,16 +30,6 @@ namespace LibHac.FsSrv
             DeviceOperator = deviceOperator;
         }
 
-        public Result OpenBisFileSystem(out IFileSystem fileSystem, string rootPath, BisPartitionId partitionId)
-        {
-            return FsCreators.BuiltInStorageFileSystemCreator.Create(out fileSystem, rootPath, partitionId);
-        }
-
-        public Result OpenSdCardFileSystem(out IFileSystem fileSystem)
-        {
-            return FsCreators.SdCardFileSystemCreator.Create(out fileSystem, false);
-        }
-
         public Result OpenGameCardStorage(out IStorage storage, GameCardHandle handle, GameCardPartitionRaw partitionId)
         {
             switch (partitionId)
@@ -146,242 +134,12 @@ namespace LibHac.FsSrv
             seed.Value.CopyTo(SdEncryptionSeed);
             // todo: FsCreators.SaveDataFileSystemCreator.SetSdCardEncryptionSeed(seed);
 
-            SaveDataIndexerManager.InvalidateSdCardIndexer(SaveDataSpaceId.SdSystem);
+            SaveDataIndexerManager.InvalidateIndexer(SaveDataSpaceId.SdSystem);
-            SaveDataIndexerManager.InvalidateSdCardIndexer(SaveDataSpaceId.SdCache);
+            SaveDataIndexerManager.InvalidateIndexer(SaveDataSpaceId.SdCache);
 
             return Result.Success;
         }
-
+        
-        public bool AllowDirectorySaveData(SaveDataSpaceId spaceId, string saveDataRootPath)
-        {
-            return spaceId == SaveDataSpaceId.User && !string.IsNullOrWhiteSpace(saveDataRootPath);
-        }
-
-        public Result DoesSaveDataExist(out bool exists, SaveDataSpaceId spaceId, ulong saveDataId)
-        {
-            exists = false;
-
-            Result rc = OpenSaveDataDirectory(out IFileSystem fileSystem, spaceId, string.Empty, true);
-            if (rc.IsFailure()) return rc;
-
-            string saveDataPath = $"/{saveDataId:x16}";
-
-            rc = fileSystem.GetEntryType(out _, saveDataPath.ToU8Span());
-
-            if (rc.IsFailure())
-            {
-                if (ResultFs.PathNotFound.Includes(rc))
-                {
-                    return Result.Success;
-                }
-
-                return rc;
-            }
-
-            exists = true;
-            return Result.Success;
-        }
-
-        public Result OpenSaveDataFileSystem(out IFileSystem fileSystem, SaveDataSpaceId spaceId, ulong saveDataId,
-            string saveDataRootPath, bool openReadOnly, SaveDataType type, bool cacheExtraData)
-        {
-            fileSystem = default;
-
-            Result rc = OpenSaveDataDirectory(out IFileSystem saveDirFs, spaceId, saveDataRootPath, true);
-            if (rc.IsFailure()) return rc;
-
-            // ReSharper disable once RedundantAssignment
-            bool allowDirectorySaveData = AllowDirectorySaveData(spaceId, saveDataRootPath);
-            bool useDeviceUniqueMac = Util.UseDeviceUniqueSaveMac(spaceId);
-
-            // Always allow directory savedata because we don't support transaction with file savedata yet
-            allowDirectorySaveData = true;
-
-            // ReSharper disable once ConditionIsAlwaysTrueOrFalse
-            if (allowDirectorySaveData)
-            {
-                rc = saveDirFs.EnsureDirectoryExists(GetSaveDataIdPath(saveDataId));
-                if (rc.IsFailure()) return rc;
-            }
-
-            // Missing save FS cache lookup
-
-            // ReSharper disable once ConditionIsAlwaysTrueOrFalse
-            rc = FsCreators.SaveDataFileSystemCreator.Create(out IFileSystem saveFs, out _, saveDirFs, saveDataId,
-                allowDirectorySaveData, useDeviceUniqueMac, type, null);
-
-            if (rc.IsFailure()) return rc;
-
-            if (cacheExtraData)
-            {
-                // todo: Missing extra data caching
-            }
-
-            fileSystem = openReadOnly ? new ReadOnlyFileSystem(saveFs) : saveFs;
-
-            return Result.Success;
-        }
-
-        public Result OpenSaveDataDirectory(out IFileSystem fileSystem, SaveDataSpaceId spaceId, string saveDataRootPath, bool openOnHostFs)
-        {
-            if (openOnHostFs && AllowDirectorySaveData(spaceId, saveDataRootPath))
-            {
-                Result rc = FsCreators.TargetManagerFileSystemCreator.Create(out IFileSystem hostFs, false);
-
-                if (rc.IsFailure())
-                {
-                    fileSystem = default;
-                    return rc;
-                }
-
-                return Util.CreateSubFileSystem(out fileSystem, hostFs, saveDataRootPath, true);
-            }
-
-            string dirName = spaceId == SaveDataSpaceId.Temporary ? "/temp" : "/save";
-
-            return OpenSaveDataDirectoryImpl(out fileSystem, spaceId, dirName, true);
-        }
-
-        public Result OpenSaveDataDirectoryImpl(out IFileSystem fileSystem, SaveDataSpaceId spaceId, string saveDirName, bool createIfMissing)
-        {
-            fileSystem = default;
-            Result rc;
-
-            switch (spaceId)
-            {
-                case SaveDataSpaceId.System:
-                    rc = OpenBisFileSystem(out IFileSystem sysFs, string.Empty, BisPartitionId.System);
-                    if (rc.IsFailure()) return rc;
-
-                    return Util.CreateSubFileSystem(out fileSystem, sysFs, saveDirName, createIfMissing);
-
-                case SaveDataSpaceId.User:
-                case SaveDataSpaceId.Temporary:
-                    rc = OpenBisFileSystem(out IFileSystem userFs, string.Empty, BisPartitionId.User);
-                    if (rc.IsFailure()) return rc;
-
-                    return Util.CreateSubFileSystem(out fileSystem, userFs, saveDirName, createIfMissing);
-
-                case SaveDataSpaceId.SdSystem:
-                case SaveDataSpaceId.SdCache:
-                    rc = OpenSdCardFileSystem(out IFileSystem sdFs);
-                    if (rc.IsFailure()) return rc;
-
-                    string sdSaveDirPath = $"/{NintendoDirectoryName}{saveDirName}";
-
-                    rc = Util.CreateSubFileSystem(out IFileSystem sdSubFs, sdFs, sdSaveDirPath, createIfMissing);
-                    if (rc.IsFailure()) return rc;
-
-                    return FsCreators.EncryptedFileSystemCreator.Create(out fileSystem, sdSubFs,
-                        EncryptedFsKeyId.Save, SdEncryptionSeed);
-
-                case SaveDataSpaceId.ProperSystem:
-                    rc = OpenBisFileSystem(out IFileSystem sysProperFs, string.Empty, BisPartitionId.SystemProperPartition);
-                    if (rc.IsFailure()) return rc;
-
-                    return Util.CreateSubFileSystem(out fileSystem, sysProperFs, saveDirName, createIfMissing);
-
-                case SaveDataSpaceId.SafeMode:
-                    rc = OpenBisFileSystem(out IFileSystem safeFs, string.Empty, BisPartitionId.SafeMode);
-                    if (rc.IsFailure()) return rc;
-
-                    return Util.CreateSubFileSystem(out fileSystem, safeFs, saveDirName, createIfMissing);
-
-                default:
-                    return ResultFs.InvalidArgument.Log();
-            }
-        }
-
-        public Result OpenSaveDataMetaFile(out IFile file, ulong saveDataId, SaveDataSpaceId spaceId, SaveDataMetaType type)
-        {
-            file = default;
-
-            string metaDirPath = $"/saveMeta/{saveDataId:x16}";
-
-            Result rc = OpenSaveDataDirectoryImpl(out IFileSystem tmpMetaDirFs, spaceId, metaDirPath, true);
-            using IFileSystem metaDirFs = tmpMetaDirFs;
-            if (rc.IsFailure()) return rc;
-
-            string metaFilePath = $"/{(int)type:x8}.meta";
-
-            return metaDirFs.OpenFile(out file, metaFilePath.ToU8Span(), OpenMode.ReadWrite);
-        }
-
-        public Result DeleteSaveDataMetaFiles(ulong saveDataId, SaveDataSpaceId spaceId)
-        {
-            Result rc = OpenSaveDataDirectoryImpl(out IFileSystem metaDirFs, spaceId, "/saveMeta", false);
-
-            using (metaDirFs)
-            {
-                if (rc.IsFailure()) return rc;
-
-                rc = metaDirFs.DeleteDirectoryRecursively($"/{saveDataId:x16}".ToU8Span());
-
-                if (rc.IsFailure() && !ResultFs.PathNotFound.Includes(rc))
-                    return rc;
-
-                return Result.Success;
-            }
-        }
-
-        public Result CreateSaveDataMetaFile(ulong saveDataId, SaveDataSpaceId spaceId, SaveDataMetaType type, long size)
-        {
-            string metaDirPath = $"/saveMeta/{saveDataId:x16}";
-
-            Result rc = OpenSaveDataDirectoryImpl(out IFileSystem tmpMetaDirFs, spaceId, metaDirPath, true);
-            using IFileSystem metaDirFs = tmpMetaDirFs;
-            if (rc.IsFailure()) return rc;
-
-            string metaFilePath = $"/{(int)type:x8}.meta";
-
-            if (size < 0) return ResultFs.OutOfRange.Log();
-
-            return metaDirFs.CreateFile(metaFilePath.ToU8Span(), size, CreateFileOptions.None);
-        }
-
-        public Result CreateSaveDataFileSystem(ulong saveDataId, ref SaveDataAttribute attribute,
-            ref SaveDataCreationInfo creationInfo, U8Span rootPath, OptionalHashSalt hashSalt, bool something)
-        {
-            // Use directory save data for now
-
-            Result rc = OpenSaveDataDirectory(out IFileSystem fileSystem, creationInfo.SpaceId, string.Empty, false);
-            if (rc.IsFailure()) return rc;
-
-            return fileSystem.EnsureDirectoryExists(GetSaveDataIdPath(saveDataId));
-        }
-
-        public Result DeleteSaveDataFileSystem(SaveDataSpaceId spaceId, ulong saveDataId, bool doSecureDelete)
-        {
-            Result rc = OpenSaveDataDirectory(out IFileSystem fileSystem, spaceId, string.Empty, false);
-
-            using (fileSystem)
-            {
-                if (rc.IsFailure()) return rc;
-
-                var saveDataPath = GetSaveDataIdPath(saveDataId).ToU8Span();
-
-                rc = fileSystem.GetEntryType(out DirectoryEntryType entryType, saveDataPath);
-                if (rc.IsFailure()) return rc;
-
-                if (entryType == DirectoryEntryType.Directory)
-                {
-                    rc = fileSystem.DeleteDirectoryRecursively(saveDataPath);
-                }
-                else
-                {
-                    if (doSecureDelete)
-                    {
-                        // Overwrite file with garbage before deleting
-                        throw new NotImplementedException();
-                    }
-
-                    rc = fileSystem.DeleteFile(saveDataPath);
-                }
-
-                return rc;
-            }
-        }
-
         public Result SetGlobalAccessLogMode(GlobalAccessLogMode mode)
         {
             LogMode = mode;
@@ -398,15 +156,5 @@ namespace LibHac.FsSrv
         {
             SaveDataIndexerManager = manager;
         }
-
-        internal Result OpenSaveDataIndexerAccessor(out SaveDataIndexerAccessor accessor, out bool neededInit, SaveDataSpaceId spaceId)
-        {
-            return SaveDataIndexerManager.OpenAccessor(out accessor, out neededInit, spaceId);
-        }
-
-        private string GetSaveDataIdPath(ulong saveDataId)
-        {
-            return $"/{saveDataId:x16}";
-        }
     }
 }

src/LibHac/FsSrv/FileSystemServer.cs

@@ -50,8 +50,16 @@ namespace LibHac.FsSrv
                 new ArrayPoolMemoryResource(), new SdHandleManager(), false));
 
             FileSystemProxyImpl fsProxy = GetFileSystemProxyServiceObject();
-            fsProxy.SetCurrentProcess(Hos.Os.GetCurrentProcessId().Value).IgnoreResult();
+            ulong processId = Hos.Os.GetCurrentProcessId().Value;
-            fsProxy.CleanUpTemporaryStorage().IgnoreResult();
+            fsProxy.SetCurrentProcess(processId).IgnoreResult();
+
+            var saveService = new SaveDataFileSystemService(fspConfig.SaveDataFileSystemService, processId);
+
+            saveService.CleanUpTemporaryStorage().IgnoreResult();
+            saveService.CleanUpSaveData().IgnoreResult();
+            saveService.CompleteSaveDataExtension().IgnoreResult();
+            saveService.FixSaveData().IgnoreResult();
+            saveService.RecoverMultiCommit().IgnoreResult();
 
             Hos.Sm.RegisterService(new FileSystemProxyService(this), "fsp-srv").IgnoreResult();
             Hos.Sm.RegisterService(new FileSystemProxyForLoaderService(this), "fsp-ldr").IgnoreResult();
@@ -82,6 +90,9 @@ namespace LibHac.FsSrv
 
         private FileSystemProxyConfiguration InitializeFileSystemProxyConfiguration(FileSystemServerConfig config)
         {
+            var saveDataIndexerManager = new SaveDataIndexerManager(Hos.Fs, SaveIndexerId,
+                new ArrayPoolMemoryResource(), new SdHandleManager(), false);
+
             var programRegistryService = new ProgramRegistryServiceImpl(this);
             var programRegistry = new ProgramRegistryImpl(programRegistryService);
 
@@ -111,11 +122,26 @@ namespace LibHac.FsSrv
 
             var ncaFsService = new NcaFileSystemServiceImpl(in ncaFsServiceConfig, config.ExternalKeySet);
 
+            var saveFsServiceConfig = new SaveDataFileSystemServiceImpl.Configuration();
+            saveFsServiceConfig.BaseFsService = baseFsService;
+            saveFsServiceConfig.HostFsCreator = config.FsCreators.HostFileSystemCreator;
+            saveFsServiceConfig.TargetManagerFsCreator = config.FsCreators.TargetManagerFileSystemCreator;
+            saveFsServiceConfig.SaveFsCreator = config.FsCreators.SaveDataFileSystemCreator;
+            saveFsServiceConfig.EncryptedFsCreator = config.FsCreators.EncryptedFileSystemCreator;
+            saveFsServiceConfig.ProgramRegistryService = programRegistryService;
+            saveFsServiceConfig.ShouldCreateDirectorySaveData = () => true;
+            saveFsServiceConfig.SaveIndexerManager = saveDataIndexerManager;
+            saveFsServiceConfig.HorizonClient = Hos;
+            saveFsServiceConfig.ProgramRegistry = programRegistry;
+
+            var saveFsService = new SaveDataFileSystemServiceImpl(in saveFsServiceConfig);
+
             var fspConfig = new FileSystemProxyConfiguration
             {
                 FsCreatorInterfaces = config.FsCreators,
                 BaseFileSystemService = baseFsService,
                 NcaFileSystemService = ncaFsService,
+                SaveDataFileSystemService = saveFsService,
                 ProgramRegistryService = programRegistryService
             };
 
@@ -124,12 +150,12 @@ namespace LibHac.FsSrv
 
         private FileSystemProxyImpl GetFileSystemProxyServiceObject()
         {
-            return new FileSystemProxyImpl(Hos, FsProxyCore);
+            return new FileSystemProxyImpl(FsProxyCore);
         }
 
         private FileSystemProxyImpl GetFileSystemProxyForLoaderServiceObject()
         {
-            return new FileSystemProxyImpl(Hos, FsProxyCore);
+            return new FileSystemProxyImpl(FsProxyCore);
         }
 
         private ProgramRegistryImpl GetProgramRegistryServiceObject()

src/LibHac/FsSrv/IFileSystemProxy.cs

@@ -25,38 +25,40 @@ namespace LibHac.FsSrv
         Result OpenSdCardFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem);
         Result FormatSdCardFileSystem();
         Result DeleteSaveDataFileSystem(ulong saveDataId);
-        Result CreateSaveDataFileSystem(ref SaveDataAttribute attribute, ref SaveDataCreationInfo creationInfo, ref SaveMetaCreateInfo metaCreateInfo);
+        Result CreateSaveDataFileSystem(in SaveDataAttribute attribute, in SaveDataCreationInfo creationInfo, in SaveDataMetaInfo metaInfo);
         Result CreateSaveDataFileSystemBySystemSaveDataId(ref SaveDataAttribute attribute, ref SaveDataCreationInfo creationInfo);
-        Result RegisterSaveDataFileSystemAtomicDeletion(ReadOnlySpan<ulong> saveDataIds);
+        Result RegisterSaveDataFileSystemAtomicDeletion(InBuffer saveDataIds);
         Result DeleteSaveDataFileSystemBySaveDataSpaceId(SaveDataSpaceId spaceId, ulong saveDataId);
         Result FormatSdCardDryRun();
         Result IsExFatSupported(out bool isSupported);
-        Result DeleteSaveDataFileSystemBySaveDataAttribute(SaveDataSpaceId spaceId, ref SaveDataAttribute attribute);
+        Result DeleteSaveDataFileSystemBySaveDataAttribute(SaveDataSpaceId spaceId, in SaveDataAttribute attribute);
         Result OpenGameCardStorage(out IStorage storage, GameCardHandle handle, GameCardPartitionRaw partitionId);
         Result OpenGameCardFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, GameCardHandle handle, GameCardPartition partitionId);
         Result ExtendSaveDataFileSystem(SaveDataSpaceId spaceId, ulong saveDataId, long dataSize, long journalSize);
-        Result DeleteCacheStorage(short index);
+        Result DeleteCacheStorage(ushort index);
-        Result GetCacheStorageSize(out long dataSize, out long journalSize, short index);
+        Result GetCacheStorageSize(out long dataSize, out long journalSize, ushort index);
-        Result CreateSaveDataFileSystemWithHashSalt(ref SaveDataAttribute attribute, ref SaveDataCreationInfo creationInfo, ref SaveMetaCreateInfo metaCreateInfo, ref HashSalt hashSalt);
+        Result CreateSaveDataFileSystemWithHashSalt(in SaveDataAttribute attribute, in SaveDataCreationInfo creationInfo, in SaveDataMetaInfo metaInfo, in HashSalt hashSalt);
-        Result OpenSaveDataFileSystem(out IFileSystem fileSystem, SaveDataSpaceId spaceId, ref SaveDataAttribute attribute);
+        Result OpenSaveDataFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, SaveDataSpaceId spaceId, in SaveDataAttribute attribute);
-        Result OpenSaveDataFileSystemBySystemSaveDataId(out IFileSystem fileSystem, SaveDataSpaceId spaceId, ref SaveDataAttribute attribute);
+        Result OpenSaveDataFileSystemBySystemSaveDataId(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, SaveDataSpaceId spaceId, in SaveDataAttribute attribute);
-        Result OpenReadOnlySaveDataFileSystem(out IFileSystem fileSystem, SaveDataSpaceId spaceId, ref SaveDataAttribute attribute);
+        Result OpenReadOnlySaveDataFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, SaveDataSpaceId spaceId, in SaveDataAttribute attribute);
-        Result ReadSaveDataFileSystemExtraDataBySaveDataSpaceId(Span<byte> extraDataBuffer, SaveDataSpaceId spaceId, ulong saveDataId);
+        Result ReadSaveDataFileSystemExtraDataBySaveDataSpaceId(OutBuffer extraDataBuffer, SaveDataSpaceId spaceId, ulong saveDataId);
-        Result ReadSaveDataFileSystemExtraData(Span<byte> extraDataBuffer, ulong saveDataId);
+        Result ReadSaveDataFileSystemExtraData(OutBuffer extraDataBuffer, ulong saveDataId);
-        Result WriteSaveDataFileSystemExtraData(ulong saveDataId, SaveDataSpaceId spaceId, ReadOnlySpan<byte> extraDataBuffer);
+        Result WriteSaveDataFileSystemExtraData(ulong saveDataId, SaveDataSpaceId spaceId, InBuffer extraDataBuffer);
         Result OpenSaveDataInfoReader(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader);
         Result OpenSaveDataInfoReaderBySaveDataSpaceId(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader, SaveDataSpaceId spaceId);
         Result OpenSaveDataInfoReaderOnlyCacheStorage(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader);
         Result OpenSaveDataInternalStorageFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, SaveDataSpaceId spaceId, ulong saveDataId);
         Result UpdateSaveDataMacForDebug(SaveDataSpaceId spaceId, ulong saveDataId);
-        Result WriteSaveDataFileSystemExtraDataWithMask(ulong saveDataId, SaveDataSpaceId spaceId, ReadOnlySpan<byte> extraDataBuffer, ReadOnlySpan<byte> maskBuffer);
+        Result WriteSaveDataFileSystemExtraDataWithMask(ulong saveDataId, SaveDataSpaceId spaceId, InBuffer extraDataBuffer, InBuffer maskBuffer);
-        Result FindSaveDataWithFilter(out long count, Span<byte> saveDataInfoBuffer, SaveDataSpaceId spaceId, ref SaveDataFilter filter);
+        Result FindSaveDataWithFilter(out long count, OutBuffer saveDataInfoBuffer, SaveDataSpaceId spaceId, in SaveDataFilter filter);
-        Result OpenSaveDataInfoReaderWithFilter(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader, SaveDataSpaceId spaceId, ref SaveDataFilter filter);
+        Result OpenSaveDataInfoReaderWithFilter(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader, SaveDataSpaceId spaceId, in SaveDataFilter filter);
-        Result ReadSaveDataFileSystemExtraDataBySaveDataAttribute(Span<byte> extraDataBuffer, SaveDataSpaceId spaceId, ref SaveDataAttribute attribute);
+        Result ReadSaveDataFileSystemExtraDataBySaveDataAttribute(OutBuffer extraDataBuffer, SaveDataSpaceId spaceId, in SaveDataAttribute attribute);
-        Result WriteSaveDataFileSystemExtraDataBySaveDataAttribute(ref SaveDataAttribute attribute, SaveDataSpaceId spaceId, ReadOnlySpan<byte> extraDataBuffer, ReadOnlySpan<byte> maskBuffer);
+        Result WriteSaveDataFileSystemExtraDataWithMaskBySaveDataAttribute(in SaveDataAttribute attribute, SaveDataSpaceId spaceId, InBuffer extraDataBuffer, InBuffer maskBuffer);
-        Result OpenSaveDataMetaFile(out IFile file, SaveDataSpaceId spaceId, ref SaveDataAttribute attribute, SaveDataMetaType type);
+        Result ReadSaveDataFileSystemExtraDataWithMaskBySaveDataAttribute(OutBuffer extraDataBuffer, SaveDataSpaceId spaceId, in SaveDataAttribute attribute, InBuffer maskBuffer);
+        Result OpenSaveDataMetaFile(out ReferenceCountedDisposable<IFileSf> file, SaveDataSpaceId spaceId, in SaveDataAttribute attribute, SaveDataMetaType type);
 
-        Result ListAccessibleSaveDataOwnerId(out int readCount, Span<Ncm.ApplicationId> idBuffer, ProgramId programId, int startIndex, int bufferIdCount);
+        Result ListAccessibleSaveDataOwnerId(out int readCount, OutBuffer idBuffer, ProgramId programId, int startIndex, int bufferIdCount);
+        Result OpenSaveDataMover(out ReferenceCountedDisposable<ISaveDataMover> saveMover, SaveDataSpaceId sourceSpaceId, SaveDataSpaceId destinationSpaceId, NativeHandle workBufferHandle, ulong workBufferSize);
         Result OpenImageDirectoryFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, ImageDirectoryId directoryId);
         Result OpenContentStorageFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, ContentStorageId storageId);
         Result OpenCloudBackupWorkStorageFileSystem(out ReferenceCountedDisposable<IFileSystemSf> fileSystem, CloudBackupWorkStorageId storageId);
@@ -73,7 +75,7 @@ namespace LibHac.FsSrv
         Result NotifySystemDataUpdateEvent();
 
         Result QuerySaveDataTotalSize(out long totalSize, long dataSize, long journalSize);
-        Result VerifySaveDataFileSystem(ulong saveDataId, Span<byte> readBuffer);
+        Result VerifySaveDataFileSystem(ulong saveDataId, OutBuffer readBuffer);
         Result CorruptSaveDataFileSystem(ulong saveDataId);
         Result CreatePaddingFile(long size);
         Result DeleteAllPaddingFiles();
@@ -84,7 +86,7 @@ namespace LibHac.FsSrv
         Result GetRightsIdAndKeyGenerationByPath(out RightsId rightsId, out byte keyGeneration, in FspPath path);
         Result SetCurrentPosixTimeWithTimeDifference(long time, int difference);
         Result GetFreeSpaceSizeForSaveData(out long freeSpaceSize, SaveDataSpaceId spaceId);
-        Result VerifySaveDataFileSystemBySaveDataSpaceId(SaveDataSpaceId spaceId, ulong saveDataId, Span<byte> readBuffer);
+        Result VerifySaveDataFileSystemBySaveDataSpaceId(SaveDataSpaceId spaceId, ulong saveDataId, OutBuffer readBuffer);
         Result CorruptSaveDataFileSystemBySaveDataSpaceId(SaveDataSpaceId spaceId, ulong saveDataId);
         Result QuerySaveDataInternalStorageTotalSize(out long size, SaveDataSpaceId spaceId, ulong saveDataId);
         Result GetSaveDataCommitId(out long commitId, SaveDataSpaceId spaceId, ulong saveDataId);
@@ -93,10 +95,10 @@ namespace LibHac.FsSrv
         Result SetSdCardAccessibility(bool isAccessible);
         Result IsSdCardAccessible(out bool isAccessible);
 
-        Result RegisterProgramIndexMapInfo(ReadOnlySpan<byte> programIndexMapInfoBuffer, int programCount);
+        Result RegisterProgramIndexMapInfo(InBuffer programIndexMapInfoBuffer, int programCount);
         Result SetBisRootForHost(BisPartitionId partitionId, ref FsPath path);
         Result SetSaveDataSize(long saveDataSize, long saveDataJournalSize);
-        Result SetSaveDataRootPath(ref FsPath path);
+        Result SetSaveDataRootPath(in FspPath path);
         Result DisableAutoSaveDataCreation();
         Result SetGlobalAccessLogMode(GlobalAccessLogMode mode);
         Result GetGlobalAccessLogMode(out GlobalAccessLogMode mode);
@@ -105,9 +107,10 @@ namespace LibHac.FsSrv
         Result OpenRegisteredUpdatePartition(out ReferenceCountedDisposable<IFileSystemSf> fileSystem);
 
         Result GetProgramIndexForAccessLog(out int programIndex, out int programCount);
+        Result UnsetSaveDataRootPath();
         Result OverrideSaveDataTransferTokenSignVerificationKey(ReadOnlySpan<byte> key);
         Result CorruptSaveDataFileSystemByOffset(SaveDataSpaceId spaceId, ulong saveDataId, long offset);
-        Result OpenMultiCommitManager(out IMultiCommitManager commitManager);
+        Result OpenMultiCommitManager(out ReferenceCountedDisposable<IMultiCommitManager> commitManager);
         Result OpenBisWiper(out ReferenceCountedDisposable<IWiper> bisWiper, NativeHandle transferMemoryHandle, ulong transferMemorySize);
     }
 }

src/LibHac/FsSrv/IMultiCommitManager.cs

@@ -1,10 +0,0 @@
-using LibHac.Fs.Fsa;
-
-namespace LibHac.FsSrv
-{
-    public interface IMultiCommitManager
-    {
-        Result Add(IFileSystem fileSystem);
-        Result Commit();
-    }
-}

src/LibHac/FsSrv/ISaveDataIndexer.cs

@@ -139,10 +139,10 @@ namespace LibHac.FsSrv
         int GetIndexCount();
 
         /// <summary>
-        /// Returns an <see cref="ISaveDataInfoReader"/> that iterates through the <see cref="SaveDataIndexer"/>.
+        /// Returns an <see cref="SaveDataInfoReaderImpl"/> that iterates through the <see cref="SaveDataIndexer"/>.
         /// </summary>
-        /// <param name="infoReader">If the method returns successfully, contains the created <see cref="ISaveDataInfoReader"/>.</param>
+        /// <param name="infoReader">If the method returns successfully, contains the created <see cref="SaveDataInfoReaderImpl"/>.</param>
         /// <returns>The <see cref="Result"/> of the operation.</returns>
-        Result OpenSaveDataInfoReader(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader);
+        Result OpenSaveDataInfoReader(out ReferenceCountedDisposable<SaveDataInfoReaderImpl> infoReader);
     }
 }

src/LibHac/FsSrv/ISaveDataIndexerManager.cs

@@ -4,8 +4,8 @@ namespace LibHac.FsSrv
 {
     public interface ISaveDataIndexerManager
     {
-        Result OpenAccessor(out SaveDataIndexerAccessor accessor, out bool neededInit, SaveDataSpaceId spaceId);
+        Result OpenSaveDataIndexerAccessor(out SaveDataIndexerAccessor accessor, out bool neededInit, SaveDataSpaceId spaceId);
-        void ResetTemporaryStorageIndexer(SaveDataSpaceId spaceId);
+        void ResetIndexer(SaveDataSpaceId spaceId);
-        void InvalidateSdCardIndexer(SaveDataSpaceId spaceId);
+        void InvalidateIndexer(SaveDataSpaceId spaceId);
     }
 }

src/LibHac/FsSrv/Impl/AccessControl.cs

@@ -830,6 +830,7 @@ namespace LibHac.FsSrv.Impl
         RegisterProgramIndexMapInfo,
         ChallengeCardExistence,
         CreateOwnSaveData,
+        DeleteOwnSaveData,
         ReadOwnSaveDataFileSystemExtraData,
         ExtendOwnSaveData,
         OpenOwnSaveDataTransferProhibiter,

src/LibHac/FsSrv/Impl/AsynchronousAccessFileSystem.cs

@@ -0,0 +1,37 @@
+using LibHac.Common;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+using LibHac.FsSystem;
+
+namespace LibHac.FsSrv.Impl
+{
+    public class AsynchronousAccessFileSystem : ForwardingFileSystem
+    {
+        public AsynchronousAccessFileSystem(ReferenceCountedDisposable<IFileSystem> baseFileSystem) : base(
+            baseFileSystem)
+        { }
+
+        protected AsynchronousAccessFileSystem(ref ReferenceCountedDisposable<IFileSystem> baseFileSystem) : base(
+            ref baseFileSystem)
+        { }
+
+        public static ReferenceCountedDisposable<IFileSystem> CreateShared(
+            ReferenceCountedDisposable<IFileSystem> baseFileSystem)
+        {
+            return new ReferenceCountedDisposable<IFileSystem>(new AsynchronousAccessFileSystem(baseFileSystem));
+        }
+
+        public static ReferenceCountedDisposable<IFileSystem> CreateShared(
+            ref ReferenceCountedDisposable<IFileSystem> fileSystem)
+        {
+            return new ReferenceCountedDisposable<IFileSystem>(new AsynchronousAccessFileSystem(ref fileSystem));
+        }
+
+        // ReSharper disable once RedundantOverriddenMember
+        protected override Result DoOpenFile(out IFile file, U8Span path, OpenMode mode)
+        {
+            // Todo: Implement
+            return base.DoOpenFile(out file, path, mode);
+        }
+    }
+}

src/LibHac/FsSrv/Impl/FileSystemInterfaceAdapter.cs

@@ -63,7 +63,7 @@ namespace LibHac.FsSrv.Impl
         /// </summary>
         /// <param name="baseFileSystem">The base file system. Will be null upon returning.</param>
         /// <param name="isHostFsRoot">Does the base file system come from the root directory of a host file system?</param>
-        public static ReferenceCountedDisposable<IFileSystemSf> CreateSharedSfFileSystem(
+        public static ReferenceCountedDisposable<IFileSystemSf> CreateShared(
             ref ReferenceCountedDisposable<IFileSystem> baseFileSystem, bool isHostFsRoot = false)
         {
             var adapter = new FileSystemInterfaceAdapter(ref baseFileSystem, isHostFsRoot);

src/LibHac/FsSrv/Impl/IEntryOpenCountSemaphoreManager.cs

@@ -0,0 +1,10 @@
+using System;
+using LibHac.FsSystem;
+
+namespace LibHac.FsSrv.Impl
+{
+    public interface IEntryOpenCountSemaphoreManager : IDisposable
+    {
+        Result TryAcquireEntryOpenCountSemaphore(out IUniqueLock semaphore);
+    }
+}

src/LibHac/FsSrv/Impl/ISaveDataMultiCommitCoreInterface.cs

@@ -0,0 +1,14 @@
+using System;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+
+namespace LibHac.FsSrv.Impl
+{
+    public interface ISaveDataMultiCommitCoreInterface : IDisposable
+    {
+        Result RecoverMultiCommit();
+        Result IsProvisionallyCommittedSaveData(out bool isProvisionallyCommitted, in SaveDataInfo saveInfo);
+        Result RecoverProvisionallyCommittedSaveData(in SaveDataInfo saveInfo, bool doRollback);
+        Result OpenMultiCommitContext(out ReferenceCountedDisposable<IFileSystem> contextFileSystem);
+    }
+}

src/LibHac/FsSrv/Impl/ISaveDataTransferCoreInterface.cs

@@ -0,0 +1,30 @@
+using System;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+using LibHac.FsSrv.Sf;
+using LibHac.Util;
+
+namespace LibHac.FsSrv.Impl
+{
+    public interface ISaveDataTransferCoreInterface : IDisposable
+    {
+        Result GetFreeSpaceSizeForSaveData(out long freeSpaceSize, SaveDataSpaceId spaceId);
+        Result QuerySaveDataTotalSize(out long totalSize, long dataSize, long journalSize);
+        Result CheckSaveDataFile(long saveDataId, SaveDataSpaceId spaceId);
+        Result CreateSaveDataFileSystemCore(in SaveDataAttribute attribute, in SaveDataCreationInfo creationInfo, in SaveDataMetaInfo metaInfo, in Optional<HashSalt> hashSalt, bool leaveUnfinalized);
+        Result GetSaveDataInfo(out SaveDataInfo saveInfo, SaveDataSpaceId spaceId, in SaveDataAttribute attribute);
+        Result ReadSaveDataFileSystemExtraDataCore(out SaveDataExtraData extraData, SaveDataSpaceId spaceId, ulong saveDataId, bool isTemporarySaveData);
+        Result WriteSaveDataFileSystemExtraDataCore(SaveDataSpaceId spaceId, ulong saveDataId, in SaveDataExtraData extraData, SaveDataType type, bool updateTimeStamp);
+        Result FinalizeSaveDataCreation(ulong saveDataId, SaveDataSpaceId spaceId);
+        Result CancelSaveDataCreation(ulong saveDataId, SaveDataSpaceId spaceId);
+        Result OpenSaveDataFile(out ReferenceCountedDisposable<IFileSf> file, SaveDataSpaceId spaceId, in SaveDataAttribute attribute, SaveDataMetaType metaType);
+        Result OpenSaveDataMetaFileRaw(out ReferenceCountedDisposable<IFile> file, SaveDataSpaceId spaceId, ulong saveDataId, SaveDataMetaType metaType, OpenMode mode);
+        Result OpenSaveDataInternalStorageFileSystemCore(out ReferenceCountedDisposable<IFileSystem> fileSystem, SaveDataSpaceId spaceId, ulong saveDataId, bool useSecondMacKey);
+        Result ExtendSaveDataFileSystem(SaveDataSpaceId spaceId, ulong saveDataId, long dataSize, long journalSize);
+        Result DeleteSaveDataFileSystemBySaveDataSpaceId(SaveDataSpaceId spaceId, ulong saveDataId);
+        Result SwapSaveDataKeyAndState(SaveDataSpaceId spaceId, ulong saveDataId1, ulong saveDataId2);
+        Result SetSaveDataState(SaveDataSpaceId spaceId, ulong saveDataId, SaveDataState state);
+        Result SetSaveDataRank(SaveDataSpaceId spaceId, ulong saveDataId, SaveDataRank rank);
+        Result OpenSaveDataIndexerAccessor(out SaveDataIndexerAccessor accessor, SaveDataSpaceId spaceId);
+    }
+}

src/LibHac/FsSrv/Impl/MultiCommitManager.cs

@@ -1,93 +1,154 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using LibHac.Common;
 using LibHac.Fs;
 using LibHac.Fs.Fsa;
 using LibHac.Fs.Shim;
+using LibHac.FsSrv.Sf;
+using LibHac.Sf;
 
 namespace LibHac.FsSrv.Impl
 {
     internal class MultiCommitManager : IMultiCommitManager
     {
         private const int MaxFileSystemCount = 10;
-        private const int CurrentContextVersion = 0x10000;
 
-        public const ulong ProgramId = 0x100000000000000;
+        public const ulong ProgramId = 0x0100000000000000;
         public const ulong SaveDataId = 0x8000000000000001;
         private const long SaveDataSize = 0xC000;
         private const long SaveJournalSize = 0xC000;
 
-        private const long ContextFileSize = 0x200;
+        private const int CurrentCommitContextVersion = 0x10000;
+        private const long CommitContextFileSize = 0x200;
 
         // /commitinfo
-        private static U8Span ContextFileName =>
+        private static U8Span CommitContextFileName =>
             new U8Span(new[] { (byte)'/', (byte)'c', (byte)'o', (byte)'m', (byte)'m', (byte)'i', (byte)'t', (byte)'i', (byte)'n', (byte)'f', (byte)'o' });
 
+        // Todo: Don't use global lock object
         private static readonly object Locker = new object();
 
-        private FileSystemProxyImpl FsProxy { get; }
+        private ReferenceCountedDisposable<ISaveDataMultiCommitCoreInterface> MultiCommitInterface { get; }
-        private List<IFileSystem> FileSystems { get; } = new List<IFileSystem>(MaxFileSystemCount);
-        private long CommitCount { get; set; }
 
-        public MultiCommitManager(FileSystemProxyImpl fsProxy)
+        private List<ReferenceCountedDisposable<IFileSystem>> FileSystems { get; } =
+            new List<ReferenceCountedDisposable<IFileSystem>>(MaxFileSystemCount);
+
+        private long Counter { get; set; }
+        private HorizonClient Hos { get; }
+
+        public MultiCommitManager(
+            ref ReferenceCountedDisposable<ISaveDataMultiCommitCoreInterface> multiCommitInterface,
+            HorizonClient client)
         {
-            FsProxy = fsProxy;
+            Hos = client;
+            MultiCommitInterface = Shared.Move(ref multiCommitInterface);
         }
 
-        public Result Add(IFileSystem fileSystem)
+        public static ReferenceCountedDisposable<IMultiCommitManager> CreateShared(
+            ref ReferenceCountedDisposable<ISaveDataMultiCommitCoreInterface> multiCommitInterface,
+            HorizonClient client)
+        {
+            var manager = new MultiCommitManager(ref multiCommitInterface, client);
+            return new ReferenceCountedDisposable<IMultiCommitManager>(manager);
+        }
+
+        public void Dispose()
+        {
+            foreach (ReferenceCountedDisposable<IFileSystem> fs in FileSystems)
+            {
+                fs.Dispose();
+            }
+        }
+
+        /// <summary>
+        /// Ensures the save data used to store the commit context exists.
+        /// </summary>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        private Result EnsureSaveDataForContext()
+        {
+            Result rc = MultiCommitInterface.Target.OpenMultiCommitContext(
+                out ReferenceCountedDisposable<IFileSystem> contextFs);
+
+            if (rc.IsFailure())
+            {
+                if (!ResultFs.TargetNotFound.Includes(rc))
+                    return rc;
+
+                rc = Hos.Fs.CreateSystemSaveData(SaveDataId, SaveDataSize, SaveJournalSize, SaveDataFlags.None);
+                if (rc.IsFailure()) return rc;
+            }
+
+            contextFs?.Dispose();
+            return Result.Success;
+        }
+
+        /// <summary>
+        /// Adds a file system to the list of file systems to be committed.
+        /// </summary>
+        /// <param name="fileSystem">The file system to be committed.</param>
+        /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
+        /// <see cref="ResultFs.MultiCommitFileSystemLimit"/>: The maximum number of file systems have been added.
+        /// <see cref="MaxFileSystemCount"/> file systems may be added to a single multi-commit.<br/>
+        /// <see cref="ResultFs.MultiCommitFileSystemAlreadyAdded"/>: The provided file system has already been added.</returns>
+        public Result Add(ReferenceCountedDisposable<IFileSystemSf> fileSystem)
         {
             if (FileSystems.Count >= MaxFileSystemCount)
                 return ResultFs.MultiCommitFileSystemLimit.Log();
 
-            // Check that the file system hasn't already been added
+            ReferenceCountedDisposable<IFileSystem> fsaFileSystem = null;
-            for (int i = 0; i < FileSystems.Count; i++)
+            try
             {
-                if (ReferenceEquals(FileSystems[i], fileSystem))
+                Result rc = fileSystem.Target.GetImpl(out fsaFileSystem);
-                    return ResultFs.MultiCommitFileSystemAlreadyAdded.Log();
+                if (rc.IsFailure()) return rc;
+
+                // Check that the file system hasn't already been added
+                foreach (ReferenceCountedDisposable<IFileSystem> fs in FileSystems)
+                {
+                    if (ReferenceEquals(fs.Target, fsaFileSystem.Target))
+                        return ResultFs.MultiCommitFileSystemAlreadyAdded.Log();
+                }
+
+                FileSystems.Add(fsaFileSystem);
+                fsaFileSystem = null;
+
+                return Result.Success;
             }
-
+            finally
-            FileSystems.Add(fileSystem);
-            return Result.Success;
-        }
-
-        public Result Commit()
-        {
-            lock (Locker)
             {
-                Result rc = CreateSave();
+                fsaFileSystem?.Dispose();
-                if (rc.IsFailure()) return rc;
-
-                rc = FsProxy.OpenMultiCommitContextSaveData(out IFileSystem contextFs);
-                if (rc.IsFailure()) return rc;
-
-                return CommitImpl(contextFs);
             }
         }
 
-        private Result CommitImpl(IFileSystem contextFileSystem)
+        /// <summary>
+        /// Commits all added file systems using <paramref name="contextFileSystem"/> to
+        /// store the <see cref="Context"/>.
+        /// </summary>
+        /// <param name="contextFileSystem">The file system where the commit context will be stored.</param>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        private Result Commit(IFileSystem contextFileSystem)
         {
-            var context = new CommitContextManager(contextFileSystem);
+            ContextUpdater context = default;
 
             try
             {
-                CommitCount = 1;
+                Counter = 1;
 
-                Result rc = context.Initialize(CommitCount, FileSystems.Count);
+                context = new ContextUpdater(contextFileSystem);
+                Result rc = context.Create(Counter, FileSystems.Count);
                 if (rc.IsFailure()) return rc;
 
-                rc = CommitProvisionally();
+                rc = CommitProvisionallyFileSystem(Counter);
                 if (rc.IsFailure()) return rc;
 
-                rc = context.SetCommittedProvisionally();
+                rc = context.CommitProvisionallyDone();
                 if (rc.IsFailure()) return rc;
 
-                foreach (IFileSystem fs in FileSystems)
+                rc = CommitFileSystem();
-                {
+                if (rc.IsFailure()) return rc;
-                    rc = fs.Commit();
-                    if (rc.IsFailure()) return rc;
-                }
 
-                rc = context.Close();
+                rc = context.CommitDone();
                 if (rc.IsFailure()) return rc;
             }
             finally
@@ -98,34 +159,45 @@ namespace LibHac.FsSrv.Impl
             return Result.Success;
         }
 
-        private Result CreateSave()
+        /// <summary>
+        /// Commits all added file systems.
+        /// </summary>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        public Result Commit()
         {
-            Result rc = FsProxy.OpenMultiCommitContextSaveData(out IFileSystem contextFs);
+            lock (Locker)
-
-            if (rc.IsFailure())
             {
-                if (!ResultFs.TargetNotFound.Includes(rc))
+                Result rc = EnsureSaveDataForContext();
-                {
-                    return rc;
-                }
-
-                rc = FsProxy.Hos.Fs.CreateSystemSaveData(SaveDataId, SaveDataSize, SaveJournalSize,
-                    SaveDataFlags.None);
                 if (rc.IsFailure()) return rc;
-            }
 
-            contextFs?.Dispose();
+                ReferenceCountedDisposable<IFileSystem> contextFs = null;
-            return Result.Success;
+                try
+                {
+                    rc = MultiCommitInterface.Target.OpenMultiCommitContext(out contextFs);
+                    if (rc.IsFailure()) return rc;
+
+                    return Commit(contextFs.Target);
+                }
+                finally
+                {
+                    contextFs?.Dispose();
+                }
+            }
         }
 
-        private Result CommitProvisionally()
+        /// <summary>
+        /// Tries to provisionally commit all the added file systems.
+        /// </summary>
+        /// <param name="counter">The provisional commit counter.</param>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        private Result CommitProvisionallyFileSystem(long counter)
         {
             Result rc = Result.Success;
             int i;
 
             for (i = 0; i < FileSystems.Count; i++)
             {
-                rc = FileSystems[i].CommitProvisionally(CommitCount);
+                rc = FileSystems[i].Target.CommitProvisionally(counter);
 
                 if (rc.IsFailure())
                     break;
@@ -136,20 +208,294 @@ namespace LibHac.FsSrv.Impl
                 // Rollback all provisional commits including the failed commit
                 for (int j = 0; j <= i; j++)
                 {
-                    FileSystems[j].Rollback().IgnoreResult();
+                    FileSystems[j].Target.Rollback().IgnoreResult();
                 }
             }
 
             return rc;
         }
 
+        /// <summary>
+        /// Tries to fully commit all the added file systems.
+        /// </summary>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        private Result CommitFileSystem()
+        {
+            // All file systems will try to be recovered committed, even if one fails.
+            // If any commits fail, the result from the first failed recovery will be returned.
+            Result result = Result.Success;
+
+            foreach (ReferenceCountedDisposable<IFileSystem> fs in FileSystems)
+            {
+                Result rc = fs.Target.Commit();
+
+                if (result.IsSuccess() && rc.IsFailure())
+                {
+                    result = rc;
+                }
+            }
+
+            return Result.Success;
+        }
+
+        /// <summary>
+        /// Recovers a multi-commit that was interrupted after all file systems had been provisionally committed.
+        /// The recovery will finish committing any file systems that are still provisionally committed.
+        /// </summary>
+        /// <param name="multiCommitInterface">The core interface used for multi-commits.</param>
+        /// <param name="contextFs">The file system containing the multi-commit context file.</param>
+        /// <param name="saveService">The save data service.</param>
+        /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
+        /// <see cref="ResultFs.InvalidMultiCommitContextVersion"/>: The version of the commit context
+        /// file isn't supported.<br/>
+        /// <see cref="ResultFs.InvalidMultiCommitContextState"/>: The multi-commit hadn't finished
+        /// provisionally committing all the file systems.</returns>
+        private static Result RecoverCommit(ISaveDataMultiCommitCoreInterface multiCommitInterface,
+            IFileSystem contextFs, SaveDataFileSystemServiceImpl saveService)
+        {
+            IFile contextFile = null;
+            try
+            {
+                // Read the multi-commit context
+                Result rc = contextFs.OpenFile(out contextFile, CommitContextFileName, OpenMode.ReadWrite);
+                if (rc.IsFailure()) return rc;
+
+                Unsafe.SkipInit(out Context context);
+                rc = contextFile.Read(out _, 0, SpanHelpers.AsByteSpan(ref context), ReadOption.None);
+                if (rc.IsFailure()) return rc;
+
+                // Note: Nintendo doesn't check if the proper amount of bytes were read, but it
+                // doesn't really matter since the context is validated.
+                if (context.Version > CurrentCommitContextVersion)
+                    return ResultFs.InvalidMultiCommitContextVersion.Log();
+
+                // All the file systems in the multi-commit must have been at least provisionally committed
+                // before we can try to recover the commit.
+                if (context.State != CommitState.ProvisionallyCommitted)
+                    return ResultFs.InvalidMultiCommitContextState.Log();
+
+                // Keep track of the first error that occurs during the recovery
+                Result recoveryResult = Result.Success;
+
+                int saveCount = 0;
+                Span<SaveDataInfo> savesToRecover = stackalloc SaveDataInfo[MaxFileSystemCount];
+
+                SaveDataIndexerAccessor accessor = null;
+                ReferenceCountedDisposable<SaveDataInfoReaderImpl> infoReader = null;
+                try
+                {
+                    rc = saveService.OpenSaveDataIndexerAccessor(out accessor, out _, SaveDataSpaceId.User);
+                    if (rc.IsFailure()) return rc;
+
+                    rc = accessor.Indexer.OpenSaveDataInfoReader(out infoReader);
+                    if (rc.IsFailure()) return rc;
+
+                    // Iterate through all the saves to find any provisionally committed save data
+                    while (true)
+                    {
+                        Unsafe.SkipInit(out SaveDataInfo info);
+
+                        rc = infoReader.Target.Read(out long readCount, OutBuffer.FromStruct(ref info));
+                        if (rc.IsFailure()) return rc;
+
+                        // Break once we're done iterating all save data
+                        if (readCount == 0)
+                            break;
+
+                        rc = multiCommitInterface.IsProvisionallyCommittedSaveData(out bool isProvisionallyCommitted,
+                            in info);
+
+                        // Note: Some saves could be missed if there are more than MaxFileSystemCount
+                        // provisionally committed saves. Not sure why Nintendo doesn't catch this.
+                        if (rc.IsSuccess() && isProvisionallyCommitted && saveCount < MaxFileSystemCount)
+                        {
+                            savesToRecover[saveCount] = info;
+                            saveCount++;
+                        }
+                    }
+                }
+                finally
+                {
+                    accessor?.Dispose();
+                    infoReader?.Dispose();
+                }
+
+                // Recover the saves by finishing their commits.
+                // All file systems will try to be recovered, even if one fails.
+                // If any commits fail, the result from the first failed recovery will be returned.
+                for (int i = 0; i < saveCount; i++)
+                {
+                    rc = multiCommitInterface.RecoverProvisionallyCommittedSaveData(in savesToRecover[i], false);
+
+                    if (recoveryResult.IsSuccess() && rc.IsFailure())
+                    {
+                        recoveryResult = rc;
+                    }
+                }
+
+                return recoveryResult;
+            }
+            finally
+            {
+                contextFile?.Dispose();
+            }
+        }
+
+        /// <summary>
+        /// Tries to recover a multi-commit using the context in the provided file system.
+        /// </summary>
+        /// <param name="multiCommitInterface">The core interface used for multi-commits.</param>
+        /// <param name="contextFs">The file system containing the multi-commit context file.</param>
+        /// <param name="saveService">The save data service.</param>
+        /// <returns></returns>
+        private static Result Recover(ISaveDataMultiCommitCoreInterface multiCommitInterface, IFileSystem contextFs,
+            SaveDataFileSystemServiceImpl saveService)
+        {
+            if (multiCommitInterface is null)
+                return ResultFs.InvalidArgument.Log();
+
+            if (contextFs is null)
+                return ResultFs.InvalidArgument.Log();
+
+            // Keep track of the first error that occurs during the recovery
+            Result recoveryResult = Result.Success;
+
+            Result rc = RecoverCommit(multiCommitInterface, contextFs, saveService);
+
+            if (rc.IsFailure())
+            {
+                // Note: Yes, the next ~50 lines are exactly the same as the code in RecoverCommit except
+                // for a single bool value. No, Nintendo doesn't split it out into its own function.
+                int saveCount = 0;
+                Span<SaveDataInfo> savesToRecover = stackalloc SaveDataInfo[MaxFileSystemCount];
+
+                SaveDataIndexerAccessor accessor = null;
+                ReferenceCountedDisposable<SaveDataInfoReaderImpl> infoReader = null;
+                try
+                {
+                    rc = saveService.OpenSaveDataIndexerAccessor(out accessor, out _, SaveDataSpaceId.User);
+                    if (rc.IsFailure()) return rc;
+
+                    rc = accessor.Indexer.OpenSaveDataInfoReader(out infoReader);
+                    if (rc.IsFailure()) return rc;
+
+                    // Iterate through all the saves to find any provisionally committed save data
+                    while (true)
+                    {
+                        Unsafe.SkipInit(out SaveDataInfo info);
+
+                        rc = infoReader.Target.Read(out long readCount, OutBuffer.FromStruct(ref info));
+                        if (rc.IsFailure()) return rc;
+
+                        // Break once we're done iterating all save data
+                        if (readCount == 0)
+                            break;
+
+                        rc = multiCommitInterface.IsProvisionallyCommittedSaveData(out bool isProvisionallyCommitted,
+                            in info);
+
+                        // Note: Some saves could be missed if there are more than MaxFileSystemCount
+                        // provisionally committed saves. Not sure why Nintendo doesn't catch this.
+                        if (rc.IsSuccess() && isProvisionallyCommitted && saveCount < MaxFileSystemCount)
+                        {
+                            savesToRecover[saveCount] = info;
+                            saveCount++;
+                        }
+                    }
+                }
+                finally
+                {
+                    accessor?.Dispose();
+                    infoReader?.Dispose();
+                }
+
+                // Recover the saves by rolling them back to the previous commit.
+                // All file systems will try to be recovered, even if one fails.
+                // If any commits fail, the result from the first failed recovery will be returned.
+                for (int i = 0; i < saveCount; i++)
+                {
+                    rc = multiCommitInterface.RecoverProvisionallyCommittedSaveData(in savesToRecover[i], true);
+
+                    if (recoveryResult.IsSuccess() && rc.IsFailure())
+                    {
+                        recoveryResult = rc;
+                    }
+                }
+            }
+
+            // Delete the commit context file
+            rc = contextFs.DeleteFile(CommitContextFileName);
+            if (rc.IsFailure()) return rc;
+
+            rc = contextFs.Commit();
+            if (rc.IsFailure()) return rc;
+
+            return recoveryResult;
+        }
+
+        /// <summary>
+        /// Recovers an interrupted multi-commit. The commit will either be completed or rolled back depending on
+        /// where in the commit process it was interrupted. Does nothing if there is no commit to recover.
+        /// </summary>
+        /// <param name="multiCommitInterface">The core interface used for multi-commits.</param>
+        /// <param name="saveService">The save data service.</param>
+        /// <returns>The <see cref="Result"/> of the operation.<br/>
+        /// <see cref="Result.Success"/>: The recovery was successful or there was no multi-commit to recover.</returns>
+        public static Result Recover(ISaveDataMultiCommitCoreInterface multiCommitInterface,
+            SaveDataFileSystemServiceImpl saveService)
+        {
+            lock (Locker)
+            {
+                bool needsRecover = true;
+                ReferenceCountedDisposable<IFileSystem> fileSystem = null;
+
+                try
+                {
+                    // Check if a multi-commit was interrupted by checking if there's a commit context file.
+                    Result rc = multiCommitInterface.OpenMultiCommitContext(out fileSystem);
+
+                    if (rc.IsFailure())
+                    {
+                        if (!ResultFs.PathNotFound.Includes(rc) && !ResultFs.TargetNotFound.Includes(rc))
+                            return rc;
+
+                        // Unable to open the multi-commit context file system, so there's nothing to recover
+                        needsRecover = false;
+                    }
+
+                    if (needsRecover)
+                    {
+                        rc = fileSystem.Target.OpenFile(out IFile file, CommitContextFileName, OpenMode.Read);
+                        file?.Dispose();
+
+                        if (rc.IsFailure())
+                        {
+                            // Unable to open the context file. No multi-commit to recover.
+                            if (ResultFs.PathNotFound.Includes(rc))
+                                needsRecover = false;
+                        }
+                    }
+
+                    if (!needsRecover)
+                        return Result.Success;
+
+                    // There was a context file. Recover the unfinished commit.
+                    return Recover(multiCommitInterface, fileSystem.Target, saveService);
+                }
+                finally
+                {
+                    fileSystem?.Dispose();
+                }
+            }
+        }
+
         [StructLayout(LayoutKind.Explicit, Size = 0x18)]
-        private struct CommitContext
+        private struct Context
         {
             [FieldOffset(0x00)] public int Version;
             [FieldOffset(0x04)] public CommitState State;
             [FieldOffset(0x08)] public int FileSystemCount;
-            [FieldOffset(0x10)] public long CommitCount; // I think?
+            [FieldOffset(0x10)] public long Counter;
         }
 
         private enum CommitState
@@ -160,35 +506,41 @@ namespace LibHac.FsSrv.Impl
             ProvisionallyCommitted = 2
         }
 
-        private struct CommitContextManager
+        private struct ContextUpdater
         {
             private IFileSystem _fileSystem;
-            private CommitContext _context;
+            private Context _context;
 
-            public CommitContextManager(IFileSystem contextFileSystem)
+            public ContextUpdater(IFileSystem contextFileSystem)
             {
                 _fileSystem = contextFileSystem;
                 _context = default;
             }
 
-            public Result Initialize(long commitCount, int fileSystemCount)
+            /// <summary>
+            /// Creates and writes the initial commit context to a file.
+            /// </summary>
+            /// <param name="commitCount">The counter.</param>
+            /// <param name="fileSystemCount">The number of file systems being committed.</param>
+            /// <returns>The <see cref="Result"/> of the operation.</returns>
+            public Result Create(long commitCount, int fileSystemCount)
             {
                 IFile contextFile = null;
 
                 try
                 {
                     // Open context file and create if it doesn't exist
-                    Result rc = _fileSystem.OpenFile(out contextFile, ContextFileName, OpenMode.Read);
+                    Result rc = _fileSystem.OpenFile(out contextFile, CommitContextFileName, OpenMode.Read);
 
                     if (rc.IsFailure())
                     {
                         if (!ResultFs.PathNotFound.Includes(rc))
                             return rc;
 
-                        rc = _fileSystem.CreateFile(ContextFileName, ContextFileSize, CreateFileOptions.None);
+                        rc = _fileSystem.CreateFile(CommitContextFileName, CommitContextFileSize, CreateFileOptions.None);
                         if (rc.IsFailure()) return rc;
 
-                        rc = _fileSystem.OpenFile(out contextFile, ContextFileName, OpenMode.Read);
+                        rc = _fileSystem.OpenFile(out contextFile, CommitContextFileName, OpenMode.Read);
                         if (rc.IsFailure()) return rc;
                     }
                 }
@@ -199,13 +551,13 @@ namespace LibHac.FsSrv.Impl
 
                 try
                 {
-                    Result rc = _fileSystem.OpenFile(out contextFile, ContextFileName, OpenMode.ReadWrite);
+                    Result rc = _fileSystem.OpenFile(out contextFile, CommitContextFileName, OpenMode.ReadWrite);
                     if (rc.IsFailure()) return rc;
 
-                    _context.Version = CurrentContextVersion;
+                    _context.Version = CurrentCommitContextVersion;
                     _context.State = CommitState.NotCommitted;
                     _context.FileSystemCount = fileSystemCount;
-                    _context.CommitCount = commitCount;
+                    _context.Counter = commitCount;
 
                     // Write the initial context to the file
                     rc = contextFile.Write(0, SpanHelpers.AsByteSpan(ref _context), WriteOption.None);
@@ -222,13 +574,18 @@ namespace LibHac.FsSrv.Impl
                 return _fileSystem.Commit();
             }
 
-            public Result SetCommittedProvisionally()
+            /// <summary>
+            /// Updates the commit context and writes it to a file, signifying that all
+            /// the file systems have been provisionally committed.
+            /// </summary>
+            /// <returns>The <see cref="Result"/> of the operation.</returns>
+            public Result CommitProvisionallyDone()
             {
                 IFile contextFile = null;
 
                 try
                 {
-                    Result rc = _fileSystem.OpenFile(out contextFile, ContextFileName, OpenMode.ReadWrite);
+                    Result rc = _fileSystem.OpenFile(out contextFile, CommitContextFileName, OpenMode.ReadWrite);
                     if (rc.IsFailure()) return rc;
 
                     _context.State = CommitState.ProvisionallyCommitted;
@@ -247,9 +604,13 @@ namespace LibHac.FsSrv.Impl
                 return _fileSystem.Commit();
             }
 
-            public Result Close()
+            /// <summary>
+            /// To be called once the multi-commit has been successfully completed. Deletes the commit context file.
+            /// </summary>
+            /// <returns>The <see cref="Result"/> of the operation.</returns>
+            public Result CommitDone()
             {
-                Result rc = _fileSystem.DeleteFile(ContextFileName);
+                Result rc = _fileSystem.DeleteFile(CommitContextFileName);
                 if (rc.IsFailure()) return rc;
 
                 rc = _fileSystem.Commit();
@@ -263,7 +624,7 @@ namespace LibHac.FsSrv.Impl
             {
                 if (_fileSystem is null) return;
 
-                _fileSystem.DeleteFile(ContextFileName).IgnoreResult();
+                _fileSystem.DeleteFile(CommitContextFileName).IgnoreResult();
                 _fileSystem.Commit().IgnoreResult();
 
                 _fileSystem = null;

src/LibHac/FsSrv/Impl/OpenCountFileSystem.cs

@@ -0,0 +1,74 @@
+using LibHac.Common;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+using LibHac.FsSystem;
+
+namespace LibHac.FsSrv.Impl
+{
+    internal class OpenCountFileSystem : ForwardingFileSystem
+    {
+        private ReferenceCountedDisposable<IEntryOpenCountSemaphoreManager> _entryCountSemaphore;
+        private IUniqueLock _mountCountSemaphore;
+
+        protected OpenCountFileSystem(ref ReferenceCountedDisposable<IFileSystem> baseFileSystem,
+            ref ReferenceCountedDisposable<IEntryOpenCountSemaphoreManager> entryCountSemaphore) : base(
+            ref baseFileSystem)
+        {
+            Shared.Move(out _entryCountSemaphore, ref entryCountSemaphore);
+        }
+
+        protected OpenCountFileSystem(ref ReferenceCountedDisposable<IFileSystem> baseFileSystem,
+            ref ReferenceCountedDisposable<IEntryOpenCountSemaphoreManager> entryCountSemaphore,
+            ref IUniqueLock mountCountSemaphore) : base(ref baseFileSystem)
+        {
+            Shared.Move(out _entryCountSemaphore, ref entryCountSemaphore);
+            Shared.Move(out _mountCountSemaphore, ref mountCountSemaphore);
+        }
+
+        public static ReferenceCountedDisposable<IFileSystem> CreateShared(
+            ref ReferenceCountedDisposable<IFileSystem> baseFileSystem,
+            ref ReferenceCountedDisposable<IEntryOpenCountSemaphoreManager> entryCountSemaphore,
+            ref IUniqueLock mountCountSemaphore)
+        {
+            var filesystem =
+                new OpenCountFileSystem(ref baseFileSystem, ref entryCountSemaphore, ref mountCountSemaphore);
+
+            return new ReferenceCountedDisposable<IFileSystem>(filesystem);
+        }
+
+        public static ReferenceCountedDisposable<IFileSystem> CreateShared(
+            ref ReferenceCountedDisposable<IFileSystem> baseFileSystem,
+            ref ReferenceCountedDisposable<IEntryOpenCountSemaphoreManager> entryCountSemaphore)
+        {
+            var filesystem =
+                new OpenCountFileSystem(ref baseFileSystem, ref entryCountSemaphore);
+
+            return new ReferenceCountedDisposable<IFileSystem>(filesystem);
+        }
+
+        // ReSharper disable once RedundantOverriddenMember
+        protected override Result DoOpenFile(out IFile file, U8Span path, OpenMode mode)
+        {
+            // Todo: Implement
+            return base.DoOpenFile(out file, path, mode);
+        }
+
+        // ReSharper disable once RedundantOverriddenMember
+        protected override Result DoOpenDirectory(out IDirectory directory, U8Span path, OpenDirectoryMode mode)
+        {
+            // Todo: Implement
+            return base.DoOpenDirectory(out directory, path, mode);
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                _entryCountSemaphore?.Dispose();
+                _mountCountSemaphore?.Dispose();
+            }
+
+            base.Dispose(disposing);
+        }
+    }
+}

src/LibHac/FsSrv/Impl/ProgramRegistryManager.cs

@@ -158,6 +158,8 @@ namespace LibHac.FsSrv.Impl
         public StorageId StorageId { get; }
         public AccessControl AccessControl { get; }
 
+        public ulong ProgramIdValue => ProgramId.Value;
+
         public ProgramInfo(FileSystemServer fsServer, ulong processId, ProgramId programId, StorageId storageId,
             ReadOnlySpan<byte> accessControlData, ReadOnlySpan<byte> accessControlDescriptor)
         {

src/LibHac/FsSrv/Impl/SaveDataProperties.cs

@@ -0,0 +1,100 @@
+using LibHac.Diag;
+using LibHac.Fs;
+
+namespace LibHac.FsSrv.Impl
+{
+    public static class SaveDataProperties
+    {
+        public static bool IsJournalingSupported(SaveDataType type)
+        {
+            switch (type)
+            {
+                case SaveDataType.System:
+                case SaveDataType.Account:
+                case SaveDataType.Bcat:
+                case SaveDataType.Device:
+                case SaveDataType.Cache:
+                    return true;
+                case SaveDataType.Temporary:
+                    return false;
+                default:
+                    Abort.UnexpectedDefault();
+                    return default;
+            }
+        }
+
+        public static bool IsMultiCommitSupported(SaveDataType type)
+        {
+            switch (type)
+            {
+                case SaveDataType.System:
+                case SaveDataType.Account:
+                case SaveDataType.Device:
+                    return true;
+                case SaveDataType.Bcat:
+                case SaveDataType.Temporary:
+                case SaveDataType.Cache:
+                    return false;
+                default:
+                    Abort.UnexpectedDefault();
+                    return default;
+            }
+        }
+
+        public static bool IsSharedOpenNeeded(SaveDataType type)
+        {
+            switch (type)
+            {
+                case SaveDataType.System:
+                case SaveDataType.Bcat:
+                case SaveDataType.Temporary:
+                case SaveDataType.Cache:
+                    return false;
+                case SaveDataType.Account:
+                case SaveDataType.Device:
+                    return true;
+                default:
+                    Abort.UnexpectedDefault();
+                    return default;
+            }
+        }
+
+        public static bool CanUseIndexerReservedArea(SaveDataType type)
+        {
+            switch (type)
+            {
+                case SaveDataType.System:
+                case SaveDataType.SystemBcat:
+                    return true;
+                case SaveDataType.Account:
+                case SaveDataType.Bcat:
+                case SaveDataType.Device:
+                case SaveDataType.Temporary:
+                case SaveDataType.Cache:
+                    return false;
+                default:
+                    Abort.UnexpectedDefault();
+                    return default;
+            }
+        }
+
+        public static bool IsSystemSaveData(SaveDataType type)
+        {
+            switch (type)
+            {
+                case SaveDataType.System:
+                case SaveDataType.SystemBcat:
+                    return true;
+                case SaveDataType.Account:
+                case SaveDataType.Bcat:
+                case SaveDataType.Device:
+                case SaveDataType.Temporary:
+                case SaveDataType.Cache:
+                    return false;
+                default:
+                    Abort.UnexpectedDefault();
+                    return default;
+            }
+        }
+    }
+}

src/LibHac/FsSrv/Impl/Utility.cs

@@ -12,7 +12,7 @@ namespace LibHac.FsSrv.Impl
     {
         public static Result EnsureDirectory(IFileSystem fileSystem, U8Span path)
         {
-            FsPath.FromSpan(out FsPath pathBuffer, ReadOnlySpan<byte>.Empty).IgnoreResult();
+            FsPath.FromSpan(out FsPath pathBuffer, path.Value).IgnoreResult();
 
             int pathLength = StringUtils.GetLength(path);
 
@@ -36,7 +36,7 @@ namespace LibHac.FsSrv.Impl
         private static Result EnsureDirectoryImpl(IFileSystem fileSystem, Span<byte> path)
         {
             // Double check the trailing separators have been trimmed
-            Assert.AssertTrue(path.Length == 0 || path[path.Length - 1] != StringTraits.DirectorySeparator);
+            Assert.AssertTrue(path.Length <= 1 || path[path.Length - 1] != StringTraits.DirectorySeparator);
 
             // Use the root path if the input path is empty
             var pathToCheck = new U8Span(path.IsEmpty ? FileSystemRootPath : path);
@@ -99,8 +99,8 @@ namespace LibHac.FsSrv.Impl
                 return ResultFs.TooLongPath.Log();
 
             // Iterate until we run out of path or find the next separator
-            int length = path.Length;
+            int length = path.Length - 1;
-            while (length > 0 && path[length - 1] != StringTraits.DirectorySeparator)
+            while (length > 0 && path[length] != StringTraits.DirectorySeparator)
             {
                 length--;
             }
@@ -112,25 +112,22 @@ namespace LibHac.FsSrv.Impl
             }
 
             // We found the length of the parent directory. Ensure it exists
-            path[length - 1] = StringTraits.NullTerminator;
+            path[length] = StringTraits.NullTerminator;
             Result rc = EnsureDirectoryImpl(fileSystem, path.Slice(0, length));
             if (rc.IsFailure()) return rc;
 
             // Restore the separator
-            path[length - 1] = StringTraits.DirectorySeparator;
+            path[length] = StringTraits.DirectorySeparator;
             return Result.Success;
         }
 
         public static Result CreateSubDirectoryFileSystem(out ReferenceCountedDisposable<IFileSystem> subDirFileSystem,
-            ReferenceCountedDisposable<IFileSystem> baseFileSystem, U8Span path, bool preserveUnc = false)
+            ReferenceCountedDisposable<IFileSystem> baseFileSystem, U8Span subPath, bool preserveUnc = false)
         {
             subDirFileSystem = default;
 
-            if (path.IsNull())
-                return ResultFs.NullptrArgument.Log();
-
             // Check if the directory exists
-            Result rc = baseFileSystem.Target.OpenDirectory(out IDirectory dir, path, OpenDirectoryMode.Directory);
+            Result rc = baseFileSystem.Target.OpenDirectory(out IDirectory dir, subPath, OpenDirectoryMode.Directory);
             if (rc.IsFailure()) return rc;
 
             dir.Dispose();
@@ -138,7 +135,7 @@ namespace LibHac.FsSrv.Impl
             var fs = new SubdirectoryFileSystem(baseFileSystem, preserveUnc);
             using (var subDirFs = new ReferenceCountedDisposable<SubdirectoryFileSystem>(fs))
             {
-                rc = subDirFs.Target.Initialize(path);
+                rc = subDirFs.Target.Initialize(subPath);
                 if (rc.IsFailure()) return rc;
 
                 subDirFileSystem = subDirFs.AddReference<IFileSystem>();

src/LibHac/FsSrv/NcaFileSystemService.cs

@@ -30,8 +30,8 @@ namespace LibHac.FsSrv
             RomMountCountSemaphore = new SemaphoreAdaptor(RomSemaphoreCount, RomSemaphoreCount);
         }
 
-        public static ReferenceCountedDisposable<NcaFileSystemService> Create(NcaFileSystemServiceImpl serviceImpl,
+        public static ReferenceCountedDisposable<NcaFileSystemService> CreateShared(
-            ulong processId)
+            NcaFileSystemServiceImpl serviceImpl, ulong processId)
         {
             // Create the service
             var ncaService = new NcaFileSystemService(serviceImpl, processId);
@@ -140,7 +140,7 @@ namespace LibHac.FsSrv
                 if (rc.IsFailure()) return rc;
 
                 // Create an SF adapter for the file system
-                fileSystem = FileSystemInterfaceAdapter.CreateSharedSfFileSystem(ref fs);
+                fileSystem = FileSystemInterfaceAdapter.CreateShared(ref fs);
 
                 return Result.Success;
             }
@@ -212,7 +212,7 @@ namespace LibHac.FsSrv
                 if (rc.IsFailure()) return rc;
 
                 // Create an SF adapter for the file system
-                fileSystem = FileSystemInterfaceAdapter.CreateSharedSfFileSystem(ref fs);
+                fileSystem = FileSystemInterfaceAdapter.CreateShared(ref fs);
 
                 return Result.Success;
             }
@@ -341,10 +341,10 @@ namespace LibHac.FsSrv
 
         private bool IsHostFs(U8Span path)
         {
-            int hostMountLength = StringUtils.GetLength(CommonMountNames.HostRootFileSystemMountName,
+            int hostMountLength = StringUtils.GetLength(CommonPaths.HostRootFileSystemMountName,
                 PathTools.MountNameLengthMax);
 
-            return StringUtils.Compare(path, CommonMountNames.HostRootFileSystemMountName, hostMountLength) == 0;
+            return StringUtils.Compare(path, CommonPaths.HostRootFileSystemMountName, hostMountLength) == 0;
         }
 
         public void Dispose()

src/LibHac/FsSrv/NcaFileSystemServiceImpl.cs

@@ -173,10 +173,10 @@ namespace LibHac.FsSrv
             info = new MountNameInfo();
             shouldContinue = true;
 
-            if (StringUtils.Compare(path, CommonMountNames.GameCardFileSystemMountName,
+            if (StringUtils.Compare(path, CommonPaths.GameCardFileSystemMountName,
-                CommonMountNames.GameCardFileSystemMountName.Length) == 0)
+                CommonPaths.GameCardFileSystemMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.GameCardFileSystemMountName.Length);
+                path = path.Slice(CommonPaths.GameCardFileSystemMountName.Length);
 
                 if (StringUtils.GetLength(path.Value, 9) < 9)
                     return ResultFs.InvalidPath.Log();
@@ -184,13 +184,13 @@ namespace LibHac.FsSrv
                 GameCardPartition partition;
                 switch ((char)path[0])
                 {
-                    case CommonMountNames.GameCardFileSystemMountNameUpdateSuffix:
+                    case CommonPaths.GameCardFileSystemMountNameUpdateSuffix:
                         partition = GameCardPartition.Update;
                         break;
-                    case CommonMountNames.GameCardFileSystemMountNameNormalSuffix:
+                    case CommonPaths.GameCardFileSystemMountNameNormalSuffix:
                         partition = GameCardPartition.Normal;
                         break;
-                    case CommonMountNames.GameCardFileSystemMountNameSecureSuffix:
+                    case CommonPaths.GameCardFileSystemMountNameSecureSuffix:
                         partition = GameCardPartition.Secure;
                         break;
                     default:
@@ -214,10 +214,10 @@ namespace LibHac.FsSrv
                 info.CanMountNca = true;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.ContentStorageSystemMountName,
+            else if (StringUtils.Compare(path, CommonPaths.ContentStorageSystemMountName,
-                CommonMountNames.ContentStorageSystemMountName.Length) == 0)
+                CommonPaths.ContentStorageSystemMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.ContentStorageSystemMountName.Length);
+                path = path.Slice(CommonPaths.ContentStorageSystemMountName.Length);
 
                 Result rc = OpenContentStorageFileSystem(out fileSystem, ContentStorageId.System);
                 if (rc.IsFailure()) return rc;
@@ -225,10 +225,10 @@ namespace LibHac.FsSrv
                 info.CanMountNca = true;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.ContentStorageUserMountName,
+            else if (StringUtils.Compare(path, CommonPaths.ContentStorageUserMountName,
-                CommonMountNames.ContentStorageUserMountName.Length) == 0)
+                CommonPaths.ContentStorageUserMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.ContentStorageUserMountName.Length);
+                path = path.Slice(CommonPaths.ContentStorageUserMountName.Length);
 
                 Result rc = OpenContentStorageFileSystem(out fileSystem, ContentStorageId.User);
                 if (rc.IsFailure()) return rc;
@@ -236,10 +236,10 @@ namespace LibHac.FsSrv
                 info.CanMountNca = true;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.ContentStorageSdCardMountName,
+            else if (StringUtils.Compare(path, CommonPaths.ContentStorageSdCardMountName,
-                CommonMountNames.ContentStorageSdCardMountName.Length) == 0)
+                CommonPaths.ContentStorageSdCardMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.ContentStorageSdCardMountName.Length);
+                path = path.Slice(CommonPaths.ContentStorageSdCardMountName.Length);
 
                 Result rc = OpenContentStorageFileSystem(out fileSystem, ContentStorageId.SdCard);
                 if (rc.IsFailure()) return rc;
@@ -247,58 +247,58 @@ namespace LibHac.FsSrv
                 info.CanMountNca = true;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.BisCalibrationFilePartitionMountName,
+            else if (StringUtils.Compare(path, CommonPaths.BisCalibrationFilePartitionMountName,
-                CommonMountNames.BisCalibrationFilePartitionMountName.Length) == 0)
+                CommonPaths.BisCalibrationFilePartitionMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.BisCalibrationFilePartitionMountName.Length);
+                path = path.Slice(CommonPaths.BisCalibrationFilePartitionMountName.Length);
 
                 Result rc = _config.BaseFsService.OpenBisFileSystem(out fileSystem, U8Span.Empty,
                     BisPartitionId.CalibrationFile);
                 if (rc.IsFailure()) return rc;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.BisSafeModePartitionMountName,
+            else if (StringUtils.Compare(path, CommonPaths.BisSafeModePartitionMountName,
-                CommonMountNames.BisSafeModePartitionMountName.Length) == 0)
+                CommonPaths.BisSafeModePartitionMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.BisSafeModePartitionMountName.Length);
+                path = path.Slice(CommonPaths.BisSafeModePartitionMountName.Length);
 
                 Result rc = _config.BaseFsService.OpenBisFileSystem(out fileSystem, U8Span.Empty,
                     BisPartitionId.SafeMode);
                 if (rc.IsFailure()) return rc;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.BisUserPartitionMountName,
+            else if (StringUtils.Compare(path, CommonPaths.BisUserPartitionMountName,
-                CommonMountNames.BisUserPartitionMountName.Length) == 0)
+                CommonPaths.BisUserPartitionMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.BisUserPartitionMountName.Length);
+                path = path.Slice(CommonPaths.BisUserPartitionMountName.Length);
 
                 Result rc = _config.BaseFsService.OpenBisFileSystem(out fileSystem, U8Span.Empty, BisPartitionId.User);
                 if (rc.IsFailure()) return rc;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.BisSystemPartitionMountName,
+            else if (StringUtils.Compare(path, CommonPaths.BisSystemPartitionMountName,
-                CommonMountNames.BisSystemPartitionMountName.Length) == 0)
+                CommonPaths.BisSystemPartitionMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.BisSystemPartitionMountName.Length);
+                path = path.Slice(CommonPaths.BisSystemPartitionMountName.Length);
 
                 Result rc = _config.BaseFsService.OpenBisFileSystem(out fileSystem, U8Span.Empty,
                     BisPartitionId.System);
                 if (rc.IsFailure()) return rc;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.SdCardFileSystemMountName,
+            else if (StringUtils.Compare(path, CommonPaths.SdCardFileSystemMountName,
-                CommonMountNames.SdCardFileSystemMountName.Length) == 0)
+                CommonPaths.SdCardFileSystemMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.SdCardFileSystemMountName.Length);
+                path = path.Slice(CommonPaths.SdCardFileSystemMountName.Length);
 
                 Result rc = _config.BaseFsService.OpenSdCardProxyFileSystem(out fileSystem);
                 if (rc.IsFailure()) return rc;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.HostRootFileSystemMountName,
+            else if (StringUtils.Compare(path, CommonPaths.HostRootFileSystemMountName,
-                CommonMountNames.HostRootFileSystemMountName.Length) == 0)
+                CommonPaths.HostRootFileSystemMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.HostRootFileSystemMountName.Length);
+                path = path.Slice(CommonPaths.HostRootFileSystemMountName.Length);
 
                 info.IsHostFs = true;
                 info.CanMountNca = true;
@@ -307,10 +307,10 @@ namespace LibHac.FsSrv
                 if (rc.IsFailure()) return rc;
             }
 
-            else if (StringUtils.Compare(path, CommonMountNames.RegisteredUpdatePartitionMountName,
+            else if (StringUtils.Compare(path, CommonPaths.RegisteredUpdatePartitionMountName,
-                CommonMountNames.RegisteredUpdatePartitionMountName.Length) == 0)
+                CommonPaths.RegisteredUpdatePartitionMountName.Length) == 0)
             {
-                path = path.Slice(CommonMountNames.RegisteredUpdatePartitionMountName.Length);
+                path = path.Slice(CommonPaths.RegisteredUpdatePartitionMountName.Length);
 
                 info.CanMountNca = true;
 
@@ -396,7 +396,7 @@ namespace LibHac.FsSrv
             if (sb.Overflowed)
                 return ResultFs.TooLongPath.Log();
 
-            Result rc = _config.TargetManagerFsCreator.GetCaseSensitivePath(out bool success, fullPath.Str);
+            Result rc = _config.TargetManagerFsCreator.NormalizeCaseOfPath(out bool success, fullPath.Str);
             if (rc.IsFailure()) return rc;
 
             // Reopen the host filesystem as case sensitive

src/LibHac/FsSrv/PathNormalizer.cs

@@ -69,7 +69,7 @@ namespace LibHac.FsSrv
             PreserveUnc = (1 << 0),
             PreserveTailSeparator = (1 << 1),
             HasMountName = (1 << 2),
-            AcceptEmpty = (1 << 3),
+            AcceptEmpty = (1 << 3)
         }
     }
 }

src/LibHac/FsSrv/Permissions.cs

@@ -1,169 +0,0 @@
-using System;
-
-namespace LibHac.FsSrv
-{
-    /// <summary>
-    /// Permissions that control which filesystems or storages can be mounted or opened.
-    /// </summary>
-    public enum AccessPermissions
-    {
-        MountLogo = 0x0,
-        MountContentMeta = 0x1,
-        MountContentControl = 0x2,
-        MountContentManual = 0x3,
-        MountContentData = 0x4,
-        MountApplicationPackage = 0x5,
-        MountSaveDataStorage = 0x6,
-        MountContentStorage = 0x7,
-        MountImageAndVideoStorage = 0x8,
-        MountCloudBackupWorkStorage = 0x9,
-        MountCustomStorage = 0xA,
-        MountBisCalibrationFile = 0xB,
-        MountBisSafeMode = 0xC,
-        MountBisUser = 0xD,
-        MountBisSystem = 0xE,
-        MountBisSystemProperEncryption = 0xF,
-        MountBisSystemProperPartition = 0x10,
-        MountSdCard = 0x11,
-        MountGameCard = 0x12,
-        MountDeviceSaveData = 0x13,
-        MountSystemSaveData = 0x14,
-        MountOthersSaveData = 0x15,
-        MountOthersSystemSaveData = 0x16,
-        OpenBisPartitionBootPartition1Root = 0x17,
-        OpenBisPartitionBootPartition2Root = 0x18,
-        OpenBisPartitionUserDataRoot = 0x19,
-        OpenBisPartitionBootConfigAndPackage2Part1 = 0x1A,
-        OpenBisPartitionBootConfigAndPackage2Part2 = 0x1B,
-        OpenBisPartitionBootConfigAndPackage2Part3 = 0x1C,
-        OpenBisPartitionBootConfigAndPackage2Part4 = 0x1D,
-        OpenBisPartitionBootConfigAndPackage2Part5 = 0x1E,
-        OpenBisPartitionBootConfigAndPackage2Part6 = 0x1F,
-        OpenBisPartitionCalibrationBinary = 0x20,
-        OpenBisPartitionCalibrationFile = 0x21,
-        OpenBisPartitionSafeMode = 0x22,
-        OpenBisPartitionUser = 0x23,
-        OpenBisPartitionSystem = 0x24,
-        OpenBisPartitionSystemProperEncryption = 0x25,
-        OpenBisPartitionSystemProperPartition = 0x26,
-        OpenSdCardStorage = 0x27,
-        OpenGameCardStorage = 0x28,
-        MountSystemDataPrivate = 0x29,
-        MountHost = 0x2A,
-        MountRegisteredUpdatePartition = 0x2B,
-        MountSaveDataInternalStorage = 0x2C,
-        NotMountCustomStorage = 0x2D
-    }
-
-    /// <summary>
-    /// Permissions that control which actions can be performed.
-    /// </summary>
-    public enum ActionPermissions
-    {
-        // Todo
-    }
-
-    public static class PermissionUtils
-    {
-        public static ulong GetPermissionMask(AccessPermissions id)
-        {
-            switch (id)
-            {
-                case AccessPermissions.MountLogo:
-                    return 0x8000000000000801;
-                case AccessPermissions.MountContentMeta:
-                    return 0x8000000000000801;
-                case AccessPermissions.MountContentControl:
-                    return 0x8000000000000801;
-                case AccessPermissions.MountContentManual:
-                    return 0x8000000000000801;
-                case AccessPermissions.MountContentData:
-                    return 0x8000000000000801;
-                case AccessPermissions.MountApplicationPackage:
-                    return 0x8000000000000801;
-                case AccessPermissions.MountSaveDataStorage:
-                    return 0x8000000000000000;
-                case AccessPermissions.MountContentStorage:
-                    return 0x8000000000000800;
-                case AccessPermissions.MountImageAndVideoStorage:
-                    return 0x8000000000001000;
-                case AccessPermissions.MountCloudBackupWorkStorage:
-                    return 0x8000000200000000;
-                case AccessPermissions.MountCustomStorage:
-                    return 0x8000000000000000;
-                case AccessPermissions.MountBisCalibrationFile:
-                    return 0x8000000000000084;
-                case AccessPermissions.MountBisSafeMode:
-                    return 0x8000000000000080;
-                case AccessPermissions.MountBisUser:
-                    return 0x8000000000008080;
-                case AccessPermissions.MountBisSystem:
-                    return 0x8000000000008080;
-                case AccessPermissions.MountBisSystemProperEncryption:
-                    return 0x8000000000000080;
-                case AccessPermissions.MountBisSystemProperPartition:
-                    return 0x8000000000000080;
-                case AccessPermissions.MountSdCard:
-                    return 0xC000000000200000;
-                case AccessPermissions.MountGameCard:
-                    return 0x8000000000000010;
-                case AccessPermissions.MountDeviceSaveData:
-                    return 0x8000000000040020;
-                case AccessPermissions.MountSystemSaveData:
-                    return 0x8000000000000028;
-                case AccessPermissions.MountOthersSaveData:
-                    return 0x8000000000000020;
-                case AccessPermissions.MountOthersSystemSaveData:
-                    return 0x8000000000000020;
-                case AccessPermissions.OpenBisPartitionBootPartition1Root:
-                    return 0x8000000000010082;
-                case AccessPermissions.OpenBisPartitionBootPartition2Root:
-                    return 0x8000000000010080;
-                case AccessPermissions.OpenBisPartitionUserDataRoot:
-                    return 0x8000000000000080;
-                case AccessPermissions.OpenBisPartitionBootConfigAndPackage2Part1:
-                    return 0x8000000000010080;
-                case AccessPermissions.OpenBisPartitionBootConfigAndPackage2Part2:
-                    return 0x8000000000010080;
-                case AccessPermissions.OpenBisPartitionBootConfigAndPackage2Part3:
-                    return 0x8000000000010080;
-                case AccessPermissions.OpenBisPartitionBootConfigAndPackage2Part4:
-                    return 0x8000000000010080;
-                case AccessPermissions.OpenBisPartitionBootConfigAndPackage2Part5:
-                    return 0x8000000000010080;
-                case AccessPermissions.OpenBisPartitionBootConfigAndPackage2Part6:
-                    return 0x8000000000010080;
-                case AccessPermissions.OpenBisPartitionCalibrationBinary:
-                    return 0x8000000000000084;
-                case AccessPermissions.OpenBisPartitionCalibrationFile:
-                    return 0x8000000000000084;
-                case AccessPermissions.OpenBisPartitionSafeMode:
-                    return 0x8000000000000080;
-                case AccessPermissions.OpenBisPartitionUser:
-                    return 0x8000000000000080;
-                case AccessPermissions.OpenBisPartitionSystem:
-                    return 0x8000000000000080;
-                case AccessPermissions.OpenBisPartitionSystemProperEncryption:
-                    return 0x8000000000000080;
-                case AccessPermissions.OpenBisPartitionSystemProperPartition:
-                    return 0x8000000000000080;
-                case AccessPermissions.OpenSdCardStorage:
-                    return 0xC000000000200000;
-                case AccessPermissions.OpenGameCardStorage:
-                    return 0x8000000000000100;
-                case AccessPermissions.MountSystemDataPrivate:
-                    return 0x8000000000100008;
-                case AccessPermissions.MountHost:
-                    return 0xC000000000400000;
-                case AccessPermissions.MountRegisteredUpdatePartition:
-                    return 0x8000000000010000;
-                case AccessPermissions.MountSaveDataInternalStorage:
-                    return 0x8000000000000000;
-                case AccessPermissions.NotMountCustomStorage:
-                    return 0x0;
-                default:
-                    throw new ArgumentOutOfRangeException(nameof(id), id, null);
-            }
-        }
-    }
-}

src/LibHac/FsSrv/ProgramIndexMapInfoManager.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using LibHac.Fs;
 using LibHac.Ncm;
+using LibHac.Util;
 
 namespace LibHac.FsSrv
 {
@@ -50,7 +51,7 @@ namespace LibHac.FsSrv
         /// <param name="programId">The program ID of the map info to get.</param>
         /// <returns>If the program ID was found, the <see cref="ProgramIndexMapInfo"/> associated
         /// with that ID; otherwise, <see langword="null"/>.</returns>
-        public ProgramIndexMapInfo? Get(ProgramId programId)
+        public Optional<ProgramIndexMapInfo> Get(ProgramId programId)
         {
             lock (MapEntries)
             {
@@ -70,12 +71,13 @@ namespace LibHac.FsSrv
         {
             lock (MapEntries)
             {
-                ProgramIndexMapInfo? mainProgramMapInfo = GetImpl((in ProgramIndexMapInfo x) => x.ProgramId == programId);
+                Optional<ProgramIndexMapInfo> mainProgramMapInfo =
+                    GetImpl((in ProgramIndexMapInfo x) => x.ProgramId == programId);
 
                 if(!mainProgramMapInfo.HasValue)
                     return ProgramId.InvalidId;
 
-                ProgramIndexMapInfo? requestedMapInfo = GetImpl((in ProgramIndexMapInfo x) =>
+                Optional<ProgramIndexMapInfo> requestedMapInfo = GetImpl((in ProgramIndexMapInfo x) =>
                     x.MainProgramId == mainProgramMapInfo.Value.MainProgramId && x.ProgramIndex == programIndex);
 
                 if (!requestedMapInfo.HasValue)
@@ -99,17 +101,17 @@ namespace LibHac.FsSrv
 
         private delegate bool EntrySelector(in ProgramIndexMapInfo candidate);
 
-        private ProgramIndexMapInfo? GetImpl(EntrySelector selector)
+        private Optional<ProgramIndexMapInfo> GetImpl(EntrySelector selector)
         {
             foreach (ProgramIndexMapInfo entry in MapEntries)
             {
                 if (selector(in entry))
                 {
-                    return entry;
+                    return new Optional<ProgramIndexMapInfo>(entry);
                 }
             }
 
-            return null;
+            return new Optional<ProgramIndexMapInfo>();
         }
 
         private void ClearImpl()

src/LibHac/FsSrv/ProgramIndexRegistryService.cs

@@ -3,21 +3,23 @@ using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using LibHac.Fs;
 using LibHac.FsSrv.Impl;
+using LibHac.Sf;
+using LibHac.Util;
 
 namespace LibHac.FsSrv
 {
     /// <summary>
-    /// Used to perform operations on the Program Index Map.
+    /// Used to perform operations on the program index registry.
     /// </summary>
     /// <remarks>Appropriate methods calls on IFileSystemProxy are forwarded to this class
     /// which then checks the calling process' permissions and performs the requested operation.
     /// <br/>Based on FS 10.0.0 (nnSdk 10.4.0)</remarks>
-    internal readonly struct ProgramRegistryService
+    internal readonly struct ProgramIndexRegistryService
     {
         private ProgramRegistryServiceImpl ServiceImpl { get; }
         private ulong ProcessId { get; }
 
-        public ProgramRegistryService(ProgramRegistryServiceImpl serviceImpl, ulong processId)
+        public ProgramIndexRegistryService(ProgramRegistryServiceImpl serviceImpl, ulong processId)
         {
             ServiceImpl = serviceImpl;
             ProcessId = processId;
@@ -33,7 +35,7 @@ namespace LibHac.FsSrv
         /// <see cref="ResultFs.PermissionDenied"/>: Insufficient permissions.<br/>
         /// <see cref="ResultFs.InvalidSize"/>: The buffer was too small to hold the specified
         /// number of <see cref="ProgramIndexMapInfo"/> entries.</returns>
-        public Result RegisterProgramIndexMapInfo(ReadOnlySpan<byte> programIndexMapInfo, int programCount)
+        public Result RegisterProgramIndexMapInfo(InBuffer programIndexMapInfo, int programCount)
         {
             // Verify the caller's permissions
             Result rc = GetProgramInfo(out ProgramInfo programInfo, ProcessId);
@@ -49,7 +51,7 @@ namespace LibHac.FsSrv
 
             // Verify that the provided buffer is large enough to hold "programCount" entries
             ReadOnlySpan<ProgramIndexMapInfo>
-                mapInfo = MemoryMarshal.Cast<byte, ProgramIndexMapInfo>(programIndexMapInfo);
+                mapInfo = MemoryMarshal.Cast<byte, ProgramIndexMapInfo>(programIndexMapInfo.Buffer);
 
             if (mapInfo.Length < programCount)
                 return ResultFs.InvalidSize.Log();
@@ -69,7 +71,7 @@ namespace LibHac.FsSrv
         /// <returns><see cref="Result.Success"/>: The operation was successful.<br/>
         /// <see cref="ResultFs.TargetProgramNotFound"/>: The calling program was not found
         /// in the program registry. Something's wrong with Loader if this happens.</returns>
-        public Result GetProgramIndexForAccessLog(out int programIndex, out int programCount)
+        public Result GetProgramIndex(out int programIndex, out int programCount)
         {
             Unsafe.SkipInit(out programIndex);
             Unsafe.SkipInit(out programCount);
@@ -79,10 +81,10 @@ namespace LibHac.FsSrv
             if (rc.IsFailure()) return rc;
 
             // Try to get map info for this process
-            ProgramIndexMapInfo? mapInfo = ServiceImpl.GetProgramIndexMapInfo(programInfo.ProgramId);
+            Optional<ProgramIndexMapInfo> mapInfo = ServiceImpl.GetProgramIndexMapInfo(programInfo.ProgramId);
 
             // Set the output program index if map info was found
-            programIndex = mapInfo?.ProgramIndex ?? 0;
+            programIndex = mapInfo.HasValue ? mapInfo.ValueRo.ProgramIndex : 0;
 
             // Set the number of programs in the current application
             programCount = ServiceImpl.GetProgramIndexMapInfoCount();

src/LibHac/FsSrv/ProgramRegistryImpl.cs

@@ -43,7 +43,7 @@ namespace LibHac.FsSrv
             if (!ProgramInfo.IsInitialProgram(_processId))
                 return ResultFs.PermissionDenied.Log();
 
-            return _registryService.RegisterProgram(processId, programId, storageId, accessControlData,
+            return _registryService.RegisterProgramInfo(processId, programId, storageId, accessControlData,
                 accessControlDescriptor);
         }
 
@@ -56,7 +56,7 @@ namespace LibHac.FsSrv
             if (!ProgramInfo.IsInitialProgram(_processId))
                 return ResultFs.PermissionDenied.Log();
 
-            return _registryService.UnregisterProgram(processId);
+            return _registryService.UnregisterProgramInfo(processId);
         }
 
         /// <inheritdoc cref="ProgramRegistryManager.GetProgramInfo"/>

src/LibHac/FsSrv/ProgramRegistryServiceImpl.cs

@@ -2,6 +2,7 @@
 using LibHac.Fs;
 using LibHac.FsSrv.Impl;
 using LibHac.Ncm;
+using LibHac.Util;
 
 namespace LibHac.FsSrv
 {
@@ -21,7 +22,7 @@ namespace LibHac.FsSrv
         }
 
         /// <inheritdoc cref="ProgramRegistryManager.RegisterProgram"/>
-        public Result RegisterProgram(ulong processId, ProgramId programId, StorageId storageId,
+        public Result RegisterProgramInfo(ulong processId, ProgramId programId, StorageId storageId,
             ReadOnlySpan<byte> accessControlData, ReadOnlySpan<byte> accessControlDescriptor)
         {
             return RegistryManager.RegisterProgram(processId, programId, storageId, accessControlData,
@@ -29,7 +30,7 @@ namespace LibHac.FsSrv
         }
 
         /// <inheritdoc cref="ProgramRegistryManager.UnregisterProgram" />
-        public Result UnregisterProgram(ulong processId)
+        public Result UnregisterProgramInfo(ulong processId)
         {
             return RegistryManager.UnregisterProgram(processId);
         }
@@ -47,13 +48,13 @@ namespace LibHac.FsSrv
         }
 
         /// <inheritdoc cref="ProgramIndexMapInfoManager.GetProgramId"/>
-        public ProgramId GetProgramId(ProgramId programId, byte programIndex)
+        public ProgramId GetProgramIdByIndex(ProgramId programId, byte programIndex)
         {
             return ProgramIndexManager.GetProgramId(programId, programIndex);
         }
 
         /// <inheritdoc cref="ProgramIndexMapInfoManager.Get"/>
-        public ProgramIndexMapInfo? GetProgramIndexMapInfo(ProgramId programId)
+        public Optional<ProgramIndexMapInfo> GetProgramIndexMapInfo(ProgramId programId)
         {
             return ProgramIndexManager.Get(programId);
         }

src/LibHac/FsSrv/SaveDataFileSystemServiceImpl.cs

@@ -0,0 +1,625 @@
+using System;
+using System.Runtime.CompilerServices;
+using LibHac.Common;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+using LibHac.FsSrv.Creators;
+using LibHac.FsSrv.Impl;
+using LibHac.FsSystem;
+using LibHac.FsSystem.Save;
+using LibHac.Ncm;
+using LibHac.Util;
+using Utility = LibHac.FsSrv.Impl.Utility;
+
+namespace LibHac.FsSrv
+{
+    public class SaveDataFileSystemServiceImpl
+    {
+        private Configuration _config;
+        private EncryptionSeed _encryptionSeed;
+
+        private ISaveDataFileSystemCacheManager _saveCacheManager;
+        // Save data extra data cache
+        // Save data porter manager
+        private bool _isSdCardAccessible;
+        // Timestamp getter
+
+        internal HorizonClient Hos => _config.HorizonClient;
+
+        public SaveDataFileSystemServiceImpl(in Configuration configuration)
+        {
+            _config = configuration;
+        }
+
+        public struct Configuration
+        {
+            public BaseFileSystemServiceImpl BaseFsService;
+            // Time service
+            public IHostFileSystemCreator HostFsCreator;
+            public ITargetManagerFileSystemCreator TargetManagerFsCreator;
+            public ISaveDataFileSystemCreator SaveFsCreator;
+            public IEncryptedFileSystemCreator EncryptedFsCreator;
+            public ProgramRegistryServiceImpl ProgramRegistryService;
+            // Buffer manager
+            public RandomDataGenerator GenerateRandomData;
+            public SaveDataTransferCryptoConfiguration SaveTransferCryptoConfig;
+            // Max save FS cache size
+            public Func<bool> ShouldCreateDirectorySaveData;
+            public ISaveDataIndexerManager SaveIndexerManager;
+
+            // LibHac additions
+            public HorizonClient HorizonClient;
+            public ProgramRegistryImpl ProgramRegistry;
+        }
+
+        internal Result GetProgramInfo(out ProgramInfo programInfo, ulong processId)
+        {
+            return _config.ProgramRegistry.GetProgramInfo(out programInfo, processId);
+        }
+
+        public Result DoesSaveDataEntityExist(out bool exists, SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            Unsafe.SkipInit(out exists);
+
+            ReferenceCountedDisposable<IFileSystem> fileSystem = null;
+            try
+            {
+                Result rc = OpenSaveDataDirectoryFileSystem(out fileSystem, spaceId, U8Span.Empty, true);
+                if (rc.IsFailure()) return rc;
+
+                // Get the path of the save data
+                Span<byte> saveDataPath = stackalloc byte[0x12];
+                var sb = new U8StringBuilder(saveDataPath);
+                sb.Append((byte)'/').AppendFormat(saveDataId, 'x', 16);
+
+                rc = fileSystem.Target.GetEntryType(out _, new U8Span(saveDataPath));
+
+                if (rc.IsSuccess())
+                {
+                    exists = true;
+                    return Result.Success;
+                }
+                else if (ResultFs.PathNotFound.Includes(rc))
+                {
+                    exists = false;
+                    return Result.Success;
+                }
+                else
+                {
+                    return rc;
+                }
+            }
+            finally
+            {
+                fileSystem?.Dispose();
+            }
+        }
+
+        public Result OpenSaveDataFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem,
+            SaveDataSpaceId spaceId, ulong saveDataId, U8Span saveDataRootPath, bool openReadOnly, SaveDataType type,
+            bool cacheExtraData)
+        {
+            fileSystem = default;
+
+            ReferenceCountedDisposable<IFileSystem> saveDirectoryFs = null;
+            ReferenceCountedDisposable<SaveDataFileSystem> cachedSaveDataFs = null;
+            ReferenceCountedDisposable<IFileSystem> saveDataFs = null;
+            try
+            {
+                Result rc = OpenSaveDataDirectoryFileSystem(out saveDirectoryFs, spaceId, saveDataRootPath, true);
+                if (rc.IsFailure()) return rc;
+
+                bool allowDirectorySaveData = IsAllowedDirectorySaveData2(spaceId, saveDataRootPath);
+
+                if (allowDirectorySaveData)
+                {
+                    Span<byte> saveDirectoryPath = stackalloc byte[0x12];
+                    var sb = new U8StringBuilder(saveDirectoryPath);
+                    sb.Append((byte)'/').AppendFormat(saveDataId, 'x', 16);
+
+                    rc = Utility.EnsureDirectory(saveDirectoryFs.Target, new U8Span(saveDirectoryPath));
+                    if (rc.IsFailure()) return rc;
+                }
+
+                if (!allowDirectorySaveData)
+                {
+                    // Todo: Missing save FS cache lookup
+                }
+
+                // ReSharper disable once ConditionIsAlwaysTrueOrFalse
+                if (saveDataFs is null)
+                {
+                    ReferenceCountedDisposable<ISaveDataExtraDataAccessor> extraDataAccessor = null;
+                    try
+                    {
+                        // Todo: Update ISaveDataFileSystemCreator
+                        bool useDeviceUniqueMac = IsDeviceUniqueMac(spaceId);
+
+                        rc = _config.SaveFsCreator.Create(out IFileSystem saveFs,
+                            out extraDataAccessor, saveDirectoryFs.Target, saveDataId,
+                            allowDirectorySaveData, useDeviceUniqueMac, type, null);
+                        if (rc.IsFailure()) return rc;
+
+                        saveDataFs = new ReferenceCountedDisposable<IFileSystem>(saveFs);
+
+                        if (cacheExtraData)
+                        {
+                            // Todo: Missing extra data caching
+                        }
+                    }
+                    finally
+                    {
+                        extraDataAccessor?.Dispose();
+                    }
+                }
+
+                if (openReadOnly)
+                {
+                    saveDataFs = ReadOnlyFileSystem.CreateShared(ref saveDataFs);
+                }
+
+                Shared.Move(out fileSystem, ref saveDataFs);
+                return Result.Success;
+            }
+            finally
+            {
+                saveDirectoryFs?.Dispose();
+                // ReSharper disable once ExpressionIsAlwaysNull
+                cachedSaveDataFs?.Dispose();
+                saveDataFs?.Dispose();
+            }
+        }
+
+        public Result OpenSaveDataMetaDirectoryFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem,
+            SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            var metaDirPath = // /saveMeta/
+                new U8Span(new[]
+                {
+                    (byte) '/', (byte) 's', (byte) 'a', (byte) 'v', (byte) 'e', (byte) 'M', (byte) 'e', (byte) 't',
+                    (byte) 'a', (byte) '/'
+                });
+
+            Span<byte> directoryName = stackalloc byte[0x1B];
+            var sb = new U8StringBuilder(directoryName);
+            sb.Append(metaDirPath).AppendFormat(saveDataId, 'x', 16);
+
+            return OpenSaveDataDirectoryFileSystemImpl(out fileSystem, spaceId, new U8Span(directoryName));
+        }
+
+        public Result OpenSaveDataInternalStorageFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem,
+            SaveDataSpaceId spaceId, ulong saveDataId, U8Span saveDataRootPath, bool useSecondMacKey)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result QuerySaveDataTotalSize(out long totalSize, int blockSize, long dataSize, long journalSize)
+        {
+            // Todo: Implement
+            totalSize = 0;
+            return Result.Success;
+        }
+
+        public Result CreateSaveDataMeta(ulong saveDataId, SaveDataSpaceId spaceId, SaveDataMetaType metaType,
+            long metaSize)
+        {
+            ReferenceCountedDisposable<IFileSystem> metaDirFs = null;
+            try
+            {
+                Result rc = OpenSaveDataMetaDirectoryFileSystem(out metaDirFs, spaceId, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                Span<byte> saveMetaPathBuffer = stackalloc byte[0xF];
+                var sb = new U8StringBuilder(saveMetaPathBuffer);
+                sb.Append((byte)'/').AppendFormat((int)metaType, 'x', 8);
+
+                return metaDirFs.Target.CreateFile(new U8Span(saveMetaPathBuffer), metaSize);
+            }
+            finally
+            {
+                metaDirFs?.Dispose();
+            }
+        }
+
+        public Result DeleteSaveDataMeta(ulong saveDataId, SaveDataSpaceId spaceId, SaveDataMetaType metaType)
+        {
+            ReferenceCountedDisposable<IFileSystem> metaDirFs = null;
+            try
+            {
+                Result rc = OpenSaveDataMetaDirectoryFileSystem(out metaDirFs, spaceId, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                Span<byte> saveMetaPathBuffer = stackalloc byte[0xF];
+                var sb = new U8StringBuilder(saveMetaPathBuffer);
+                sb.Append((byte)'/').AppendFormat((int)metaType, 'x', 8);
+
+                return metaDirFs.Target.DeleteFile(new U8Span(saveMetaPathBuffer));
+            }
+            finally
+            {
+                metaDirFs?.Dispose();
+            }
+        }
+
+        public Result DeleteAllSaveDataMetas(ulong saveDataId, SaveDataSpaceId spaceId)
+        {
+            var metaDirPath = // /saveMeta
+                new U8Span(new[]
+                {
+                    (byte) '/', (byte) 's', (byte) 'a', (byte) 'v', (byte) 'e', (byte) 'M', (byte) 'e', (byte) 't',
+                    (byte) 'a'
+                });
+
+            ReferenceCountedDisposable<IFileSystem> fileSystem = null;
+            try
+            {
+                Result rc = OpenSaveDataDirectoryFileSystemImpl(out fileSystem, spaceId, metaDirPath, false);
+                if (rc.IsFailure()) return rc;
+
+                // Get the path of the save data meta
+                Span<byte> saveDataPathBuffer = stackalloc byte[0x12];
+                var sb = new U8StringBuilder(saveDataPathBuffer);
+                sb.Append((byte)'/').AppendFormat(saveDataId, 'x', 16);
+
+                // Delete the save data's meta directory, ignoring the error if the directory is already gone
+                rc = fileSystem.Target.DeleteDirectoryRecursively(new U8Span(saveDataPathBuffer));
+
+                if (rc.IsFailure() && !ResultFs.PathNotFound.Includes(rc))
+                    return rc;
+
+                return Result.Success;
+            }
+            finally
+            {
+                fileSystem?.Dispose();
+            }
+        }
+
+        public Result OpenSaveDataMeta(out IFile metaFile, ulong saveDataId, SaveDataSpaceId spaceId,
+            SaveDataMetaType metaType)
+        {
+            metaFile = default;
+
+            ReferenceCountedDisposable<IFileSystem> metaDirFs = null;
+            try
+            {
+                Result rc = OpenSaveDataMetaDirectoryFileSystem(out metaDirFs, spaceId, saveDataId);
+                if (rc.IsFailure()) return rc;
+
+                Span<byte> saveMetaPathBuffer = stackalloc byte[0xF];
+                var sb = new U8StringBuilder(saveMetaPathBuffer);
+                sb.Append((byte)'/').AppendFormat((int)metaType, 'x', 8);
+
+                return metaDirFs.Target.OpenFile(out metaFile, new U8Span(saveMetaPathBuffer), OpenMode.ReadWrite);
+            }
+            finally
+            {
+                metaDirFs?.Dispose();
+            }
+        }
+
+        public Result CreateSaveDataFileSystem(ulong saveDataId, in SaveDataAttribute attribute,
+            in SaveDataCreationInfo creationInfo, U8Span saveDataRootPath, in Optional<HashSalt> hashSalt,
+            bool skipFormat)
+        {
+            // Use directory save data for now
+
+            ReferenceCountedDisposable<IFileSystem> fileSystem = null;
+            try
+            {
+                Result rc = OpenSaveDataDirectoryFileSystem(out fileSystem, creationInfo.SpaceId, saveDataRootPath,
+                    false);
+                if (rc.IsFailure()) return rc;
+
+                Span<byte> saveDataPathBuffer = stackalloc byte[0x12];
+                var sb = new U8StringBuilder(saveDataPathBuffer);
+                sb.Append((byte)'/').AppendFormat(saveDataId, 'x', 16);
+
+                if (_config.ShouldCreateDirectorySaveData())
+                {
+                    return Utility.EnsureDirectory(fileSystem.Target, new U8Span(saveDataPathBuffer));
+                }
+                else
+                {
+                    throw new NotImplementedException();
+                }
+            }
+            finally
+            {
+                fileSystem?.Dispose();
+            }
+        }
+
+        private Result WipeData(IFileSystem fileSystem, U8Span filePath, RandomDataGenerator random)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result DeleteSaveDataFileSystem(SaveDataSpaceId spaceId, ulong saveDataId, bool wipeSaveFile,
+            U8Span saveDataRootPath)
+        {
+            ReferenceCountedDisposable<IFileSystem> fileSystem = null;
+            try
+            {
+                // Open the directory containing the save data
+                Result rc = OpenSaveDataDirectoryFileSystem(out fileSystem, spaceId, saveDataRootPath, false);
+                if (rc.IsFailure()) return rc;
+
+                // Get the path of the save data
+                Span<byte> saveDataPathBuffer = stackalloc byte[0x12];
+                var saveDataPath = new U8Span(saveDataPathBuffer);
+
+                var sb = new U8StringBuilder(saveDataPathBuffer);
+                sb.Append((byte)'/').AppendFormat(saveDataId, 'x', 16);
+
+                // Check if the save data is a file or a directory
+                rc = fileSystem.Target.GetEntryType(out DirectoryEntryType entryType, saveDataPath);
+                if (rc.IsFailure()) return rc;
+
+                // Delete the save data, wiping the file if needed
+                if (entryType == DirectoryEntryType.Directory)
+                {
+                    rc = fileSystem.Target.DeleteDirectoryRecursively(saveDataPath);
+                    if (rc.IsFailure()) return rc;
+                }
+                else
+                {
+                    if (wipeSaveFile)
+                    {
+                        WipeData(fileSystem.Target, saveDataPath, _config.GenerateRandomData).IgnoreResult();
+                    }
+
+                    rc = fileSystem.Target.DeleteDirectoryRecursively(saveDataPath);
+                    if (rc.IsFailure()) return rc;
+                }
+
+                return Result.Success;
+            }
+            finally
+            {
+                fileSystem?.Dispose();
+            }
+        }
+
+        public Result ReadSaveDataFileSystemExtraData(out SaveDataExtraData extraData, SaveDataSpaceId spaceId,
+            ulong saveDataId, SaveDataType type, U8Span saveDataRootPath)
+        {
+            // Todo: Find a way to store extra data for directory save data
+            extraData = default;
+            return Result.Success;
+        }
+
+        public Result WriteSaveDataFileSystemExtraData(SaveDataSpaceId spaceId, ulong saveDataId,
+            in SaveDataExtraData extraData, U8Span saveDataRootPath, SaveDataType type, bool updateTimeStamp)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result CorruptSaveDataFileSystem(SaveDataSpaceId spaceId, ulong saveDataId, long offset,
+            U8Span saveDataRootPath)
+        {
+            throw new NotImplementedException();
+        }
+
+        private bool IsSaveEmulated(U8Span saveDataRootPath)
+        {
+            return !saveDataRootPath.IsEmpty();
+        }
+
+        public Result OpenSaveDataDirectoryFileSystem(out ReferenceCountedDisposable<IFileSystem> fileSystem,
+            SaveDataSpaceId spaceId, U8Span saveDataRootPath, bool allowEmulatedSave)
+        {
+            if (allowEmulatedSave && IsAllowedDirectorySaveData(spaceId, saveDataRootPath))
+            {
+                fileSystem = default;
+                ReferenceCountedDisposable<IFileSystem> tmFs = null;
+
+                try
+                {
+                    // Ensure the target save data directory exists
+                    Result rc = _config.TargetManagerFsCreator.Create(out tmFs, false);
+                    if (rc.IsFailure()) return rc;
+
+                    rc = Utility.EnsureDirectory(tmFs.Target, saveDataRootPath);
+                    if (rc.IsFailure())
+                        return ResultFs.SaveDataRootPathUnavailable.LogConverted(rc);
+
+                    tmFs.Dispose();
+
+                    // Nintendo does a straight copy here without checking the input path length,
+                    // stopping before the null terminator.
+                    // FsPath used instead of stackalloc for convenience 
+                    FsPath.FromSpan(out FsPath path, saveDataRootPath).IgnoreResult();
+
+                    rc = _config.TargetManagerFsCreator.NormalizeCaseOfPath(out bool isTargetFsCaseSensitive, path.Str);
+                    if (rc.IsFailure()) return rc;
+
+                    rc = _config.TargetManagerFsCreator.Create(out tmFs, isTargetFsCaseSensitive);
+                    if (rc.IsFailure()) return rc;
+
+                    return Utility.CreateSubDirectoryFileSystem(out fileSystem, tmFs, new U8Span(path.Str), true);
+                }
+                finally
+                {
+                    tmFs?.Dispose();
+                }
+            }
+
+            ReadOnlySpan<byte> saveDirName;
+
+            if (spaceId == SaveDataSpaceId.Temporary)
+            {
+                saveDirName = new[] { (byte)'/', (byte)'t', (byte)'e', (byte)'m', (byte)'p' }; // /temp
+            }
+            else
+            {
+                saveDirName = new[] { (byte)'/', (byte)'s', (byte)'a', (byte)'v', (byte)'e' }; // /save
+            }
+
+            return OpenSaveDataDirectoryFileSystemImpl(out fileSystem, spaceId, new U8Span(saveDirName), true);
+        }
+
+        public Result OpenSaveDataDirectoryFileSystemImpl(out ReferenceCountedDisposable<IFileSystem> fileSystem,
+            SaveDataSpaceId spaceId, U8Span basePath)
+        {
+            return OpenSaveDataDirectoryFileSystemImpl(out fileSystem, spaceId, basePath, true);
+        }
+
+        public Result OpenSaveDataDirectoryFileSystemImpl(out ReferenceCountedDisposable<IFileSystem> fileSystem,
+            SaveDataSpaceId spaceId, U8Span basePath, bool createIfMissing)
+        {
+            fileSystem = default;
+
+            ReferenceCountedDisposable<IFileSystem> tempFs = null;
+            ReferenceCountedDisposable<IFileSystem> tempSubFs = null;
+            try
+            {
+                Result rc;
+
+                switch (spaceId)
+                {
+                    case SaveDataSpaceId.System:
+                        rc = _config.BaseFsService.OpenBisFileSystem(out tempFs, U8Span.Empty, BisPartitionId.System, true);
+                        if (rc.IsFailure()) return rc;
+
+                        return Utility.WrapSubDirectory(out fileSystem, tempFs, basePath, createIfMissing);
+
+                    case SaveDataSpaceId.User:
+                    case SaveDataSpaceId.Temporary:
+                        rc = _config.BaseFsService.OpenBisFileSystem(out tempFs, U8Span.Empty, BisPartitionId.User, true);
+                        if (rc.IsFailure()) return rc;
+
+                        return Utility.WrapSubDirectory(out fileSystem, tempFs, basePath, createIfMissing);
+
+                    case SaveDataSpaceId.SdSystem:
+                    case SaveDataSpaceId.SdCache:
+                        rc = _config.BaseFsService.OpenSdCardProxyFileSystem(out tempFs, true);
+                        if (rc.IsFailure()) return rc;
+
+                        Unsafe.SkipInit(out FsPath path);
+                        var sb = new U8StringBuilder(path.Str);
+                        sb.Append((byte)'/')
+                            .Append(basePath.Value)
+                            .Append((byte)'/')
+                            .Append(CommonPaths.SdCardNintendoRootDirectoryName);
+
+                        rc = Utility.WrapSubDirectory(out tempSubFs, tempFs, path, createIfMissing);
+                        if (rc.IsFailure()) return rc;
+
+                        return _config.EncryptedFsCreator.Create(out fileSystem, tempSubFs, EncryptedFsKeyId.Save,
+                            in _encryptionSeed);
+
+                    case SaveDataSpaceId.ProperSystem:
+                        rc = _config.BaseFsService.OpenBisFileSystem(out tempFs, U8Span.Empty, BisPartitionId.SystemProperPartition, true);
+                        if (rc.IsFailure()) return rc;
+
+                        return Utility.WrapSubDirectory(out fileSystem, tempFs, basePath, createIfMissing);
+
+                    case SaveDataSpaceId.SafeMode:
+                        rc = _config.BaseFsService.OpenBisFileSystem(out tempFs, U8Span.Empty, BisPartitionId.SafeMode, true);
+                        if (rc.IsFailure()) return rc;
+
+                        return Utility.WrapSubDirectory(out fileSystem, tempFs, basePath, createIfMissing);
+
+                    default:
+                        return ResultFs.InvalidArgument.Log();
+                }
+            }
+            finally
+            {
+                tempFs?.Dispose();
+                tempSubFs?.Dispose();
+            }
+        }
+
+        public Result SetSdCardEncryptionSeed(in EncryptionSeed seed)
+        {
+            _encryptionSeed = seed;
+
+            _config.SaveFsCreator.SetSdCardEncryptionSeed(seed.Value);
+            _config.SaveIndexerManager.InvalidateIndexer(SaveDataSpaceId.SdSystem);
+            _config.SaveIndexerManager.InvalidateIndexer(SaveDataSpaceId.SdCache);
+
+            return Result.Success;
+        }
+
+        public Result IsProvisionallyCommittedSaveData(out bool isProvisionallyCommitted, in SaveDataInfo saveInfo)
+        {
+            throw new NotImplementedException();
+        }
+
+        public bool IsAllowedDirectorySaveData(SaveDataSpaceId spaceId, U8Span saveDataRootPath)
+        {
+            return spaceId == SaveDataSpaceId.User && IsSaveEmulated(saveDataRootPath);
+        }
+
+        // Todo: remove once file save data is supported
+        // Used to always allow directory save data in OpenSaveDataFileSystem
+        public bool IsAllowedDirectorySaveData2(SaveDataSpaceId spaceId, U8Span saveDataRootPath)
+        {
+            // Todo: remove "|| true" once file save data is supported
+            // ReSharper disable once ConditionIsAlwaysTrueOrFalse
+            return spaceId == SaveDataSpaceId.User && IsSaveEmulated(saveDataRootPath) || true;
+        }
+
+        public bool IsDeviceUniqueMac(SaveDataSpaceId spaceId)
+        {
+            return spaceId == SaveDataSpaceId.System ||
+                   spaceId == SaveDataSpaceId.User ||
+                   spaceId == SaveDataSpaceId.Temporary ||
+                   spaceId == SaveDataSpaceId.ProperSystem ||
+                   spaceId == SaveDataSpaceId.SafeMode;
+        }
+
+        public void SetSdCardAccessibility(bool isAccessible)
+        {
+            _isSdCardAccessible = isAccessible;
+        }
+
+        public bool IsSdCardAccessible()
+        {
+            return _isSdCardAccessible;
+        }
+
+        /// <summary>
+        /// Gets the program ID of the save data associated with the specified programID.
+        /// </summary>
+        /// <remarks>In a standard application the program ID will be the same as the input program ID.
+        /// In multi-program applications all sub-programs use the program ID of the main program
+        /// for their save data. The main program always has a program index of 0.</remarks>
+        /// <param name="programId">The program ID to get the save data program ID for.</param>
+        /// <returns>The program ID of the save data.</returns>
+        public ProgramId ResolveDefaultSaveDataReferenceProgramId(in ProgramId programId)
+        {
+            // First check if there's an entry in the program index map with the program ID and program index 0
+            ProgramId mainProgramId = _config.ProgramRegistryService.GetProgramIdByIndex(programId, 0);
+
+            if (mainProgramId != ProgramId.InvalidId)
+            {
+                return mainProgramId;
+            }
+
+            // Check if there's an entry with the program ID, ignoring program index
+            Optional<ProgramIndexMapInfo> mapInfo = _config.ProgramRegistryService.GetProgramIndexMapInfo(programId);
+
+            if (mapInfo.HasValue)
+            {
+                return mapInfo.Value.MainProgramId;
+            }
+
+            // The program ID isn't in the program index map. Probably running a single-program application
+            return programId;
+        }
+
+        public void ResetTemporaryStorageIndexer()
+        {
+            _config.SaveIndexerManager.ResetIndexer(SaveDataSpaceId.Temporary);
+        }
+
+        public Result OpenSaveDataIndexerAccessor(out SaveDataIndexerAccessor accessor, out bool neededInit,
+            SaveDataSpaceId spaceId)
+        {
+            return _config.SaveIndexerManager.OpenSaveDataIndexerAccessor(out accessor, out neededInit, spaceId);
+        }
+    }
+}

src/LibHac/FsSrv/SaveDataIndexer.cs

@@ -8,7 +8,9 @@ using LibHac.Common;
 using LibHac.Diag;
 using LibHac.Fs;
 using LibHac.Fs.Shim;
+using LibHac.FsSrv.Sf;
 using LibHac.Kvdb;
+using LibHac.Sf;
 
 namespace LibHac.FsSrv
 {
@@ -504,7 +506,7 @@ namespace LibHac.FsSrv
             }
         }
 
-        public Result OpenSaveDataInfoReader(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader)
+        public Result OpenSaveDataInfoReader(out ReferenceCountedDisposable<SaveDataInfoReaderImpl> infoReader)
         {
             infoReader = default;
 
@@ -522,7 +524,7 @@ namespace LibHac.FsSrv
                     rc = RegisterReader(reader);
                     if (rc.IsFailure()) return rc;
 
-                    infoReader = reader.AddReference<ISaveDataInfoReader>();
+                    infoReader = reader.AddReference<SaveDataInfoReaderImpl>();
                     return Result.Success;
                 }
             }
@@ -802,7 +804,7 @@ namespace LibHac.FsSrv
             }
         }
 
-        private class Reader : ISaveDataInfoReader
+        private class Reader : SaveDataInfoReaderImpl, ISaveDataInfoReader
         {
             private readonly SaveDataIndexer _indexer;
             private FlatMapKeyValueStore<SaveDataAttribute>.Iterator _iterator;
@@ -816,7 +818,7 @@ namespace LibHac.FsSrv
                 _iterator = indexer.GetBeginIterator();
             }
 
-            public Result Read(out long readCount, Span<byte> saveDataInfoBuffer)
+            public Result Read(out long readCount, OutBuffer saveDataInfoBuffer)
             {
                 Unsafe.SkipInit(out readCount);
 
@@ -828,7 +830,7 @@ namespace LibHac.FsSrv
                         return ResultFs.InvalidSaveDataInfoReader.Log();
                     }
 
-                    Span<SaveDataInfo> outInfo = MemoryMarshal.Cast<byte, SaveDataInfo>(saveDataInfoBuffer);
+                    Span<SaveDataInfo> outInfo = MemoryMarshal.Cast<byte, SaveDataInfo>(saveDataInfoBuffer.Buffer);
 
                     int i;
                     for (i = 0; !_iterator.IsEnd() && i < outInfo.Length; i++)

src/LibHac/FsSrv/SaveDataIndexerLite.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Runtime.InteropServices;
 using LibHac.Fs;
+using LibHac.FsSrv.Sf;
+using LibHac.Sf;
 
 namespace LibHac.FsSrv
 {
@@ -207,7 +209,7 @@ namespace LibHac.FsSrv
             return 1;
         }
 
-        public Result OpenSaveDataInfoReader(out ReferenceCountedDisposable<ISaveDataInfoReader> infoReader)
+        public Result OpenSaveDataInfoReader(out ReferenceCountedDisposable<SaveDataInfoReaderImpl> infoReader)
         {
             SaveDataIndexerLiteInfoReader reader;
 
@@ -220,12 +222,12 @@ namespace LibHac.FsSrv
                 reader = new SaveDataIndexerLiteInfoReader();
             }
 
-            infoReader = new ReferenceCountedDisposable<ISaveDataInfoReader>(reader);
+            infoReader = new ReferenceCountedDisposable<SaveDataInfoReaderImpl>(reader);
 
             return Result.Success;
         }
 
-        private class SaveDataIndexerLiteInfoReader : ISaveDataInfoReader
+        private class SaveDataIndexerLiteInfoReader : SaveDataInfoReaderImpl, ISaveDataInfoReader
         {
             private bool _finishedIterating;
             private SaveDataInfo _info;
@@ -240,9 +242,9 @@ namespace LibHac.FsSrv
                 SaveDataIndexer.GenerateSaveDataInfo(out _info, in key, in value);
             }
 
-            public Result Read(out long readCount, Span<byte> saveDataInfoBuffer)
+            public Result Read(out long readCount, OutBuffer saveDataInfoBuffer)
             {
-                Span<SaveDataInfo> outInfo = MemoryMarshal.Cast<byte, SaveDataInfo>(saveDataInfoBuffer);
+                Span<SaveDataInfo> outInfo = MemoryMarshal.Cast<byte, SaveDataInfo>(saveDataInfoBuffer.Buffer);
 
                 // Note: Nintendo doesn't check if the buffer is large enough here
                 if (_finishedIterating || outInfo.IsEmpty)

src/LibHac/FsSrv/SaveDataIndexerManager.cs

@@ -1,9 +1,9 @@
 using System;
-using System.Threading;
 using LibHac.Common;
 using LibHac.Diag;
 using LibHac.Fs;
 using LibHac.FsSrv.Storage;
+using LibHac.Util;
 
 namespace LibHac.FsSrv
 {
@@ -54,97 +54,112 @@ namespace LibHac.FsSrv
         /// if the indexer needed to be initialized.</param>
         /// <param name="spaceId">The <see cref="SaveDataSpaceId"/> of the indexer to open.</param>
         /// <returns>The <see cref="Result"/> of the operation.</returns>
-        public Result OpenAccessor(out SaveDataIndexerAccessor accessor, out bool neededInit, SaveDataSpaceId spaceId)
+        public Result OpenSaveDataIndexerAccessor(out SaveDataIndexerAccessor accessor, out bool neededInit,
+            SaveDataSpaceId spaceId)
         {
             neededInit = false;
+            UniqueLock indexerLock = default;
 
             if (IsBisUserRedirectionEnabled && spaceId == SaveDataSpaceId.User)
             {
                 spaceId = SaveDataSpaceId.ProperSystem;
             }
 
-            switch (spaceId)
+            try
             {
-                case SaveDataSpaceId.System:
+                ISaveDataIndexer indexer;
-                case SaveDataSpaceId.User:
+                switch (spaceId)
-                    Monitor.Enter(_bisIndexer.Locker);
+                {
+                    case SaveDataSpaceId.System:
+                    case SaveDataSpaceId.User:
+                        indexerLock = new UniqueLock(_bisIndexer.Locker);
 
-                    if (!_bisIndexer.IsInitialized)
+                        if (!_bisIndexer.IsInitialized)
-                    {
+                        {
-                        _bisIndexer.Indexer = new SaveDataIndexer(FsClient, new U8Span(SystemIndexerMountName),
+                            _bisIndexer.Indexer = new SaveDataIndexer(FsClient, new U8Span(SystemIndexerMountName),
-                            SaveDataSpaceId.System, SaveDataId, MemoryResource);
+                                SaveDataSpaceId.System, SaveDataId, MemoryResource);
 
-                        neededInit = true;
+                            neededInit = true;
-                    }
+                        }
 
-                    accessor = new SaveDataIndexerAccessor(_bisIndexer.Indexer, _bisIndexer.Locker);
+                        indexer = _bisIndexer.Indexer;
-                    return Result.Success;
+                        break;
+                    case SaveDataSpaceId.SdSystem:
+                    case SaveDataSpaceId.SdCache:
+                        // ReSharper doesn't realize that UniqueLock locks the indexer's lock object
+                        // ReSharper disable InconsistentlySynchronizedField
+                        indexerLock = new UniqueLock(_sdCardIndexer.Locker);
 
-                case SaveDataSpaceId.SdSystem:
+                        // We need to reinitialize the indexer if the SD card has changed
-                case SaveDataSpaceId.SdCache:
+                        if (!_sdCardHandleManager.IsValid(in _sdCardHandle) && _sdCardIndexer.IsInitialized)
-                    Monitor.Enter(_sdCardIndexer.Locker);
+                        {
+                            _sdCardIndexer.Indexer.Dispose();
+                            _sdCardIndexer.Indexer = null;
+                        }
 
-                    // We need to reinitialize the indexer if the SD card has changed
+                        if (!_sdCardIndexer.IsInitialized)
-                    if (!_sdCardHandleManager.IsValid(in _sdCardHandle) && _sdCardIndexer.IsInitialized)
+                        {
-                    {
+                            _sdCardIndexer.Indexer = new SaveDataIndexer(FsClient, new U8Span(SdCardIndexerMountName),
-                        _sdCardIndexer.Indexer.Dispose();
+                                SaveDataSpaceId.SdSystem, SaveDataId, MemoryResource);
-                        _sdCardIndexer.Indexer = null;
-                    }
 
-                    if (!_sdCardIndexer.IsInitialized)
+                            _sdCardHandleManager.GetHandle(out _sdCardHandle).IgnoreResult();
-                    {
-                        _sdCardIndexer.Indexer = new SaveDataIndexer(FsClient, new U8Span(SdCardIndexerMountName),
-                            SaveDataSpaceId.SdSystem, SaveDataId, MemoryResource);
 
-                        _sdCardHandleManager.GetHandle(out _sdCardHandle).IgnoreResult();
+                            neededInit = true;
+                        }
 
-                        neededInit = true;
+                        indexer = _sdCardIndexer.Indexer;
-                    }
+                        // ReSharper restore InconsistentlySynchronizedField
 
-                    accessor = new SaveDataIndexerAccessor(_sdCardIndexer.Indexer, _sdCardIndexer.Locker);
+                        break;
-                    return Result.Success;
+                    case SaveDataSpaceId.Temporary:
+                        indexerLock = new UniqueLock(_tempIndexer.Locker);
 
-                case SaveDataSpaceId.Temporary:
+                        indexer = _tempIndexer.Indexer;
-                    Monitor.Enter(_tempIndexer.Locker);
+                        break;
+                    case SaveDataSpaceId.ProperSystem:
+                        indexerLock = new UniqueLock(_properSystemIndexer.Locker);
 
-                    accessor = new SaveDataIndexerAccessor(_tempIndexer.Indexer, _tempIndexer.Locker);
+                        if (!_properSystemIndexer.IsInitialized)
-                    return Result.Success;
+                        {
+                            _properSystemIndexer.Indexer = new SaveDataIndexer(FsClient,
+                                new U8Span(ProperSystemIndexerMountName),
+                                SaveDataSpaceId.ProperSystem, SaveDataId, MemoryResource);
 
-                case SaveDataSpaceId.ProperSystem:
+                            neededInit = true;
-                    Monitor.Enter(_properSystemIndexer.Locker);
+                        }
 
-                    if (!_properSystemIndexer.IsInitialized)
+                        indexer = _properSystemIndexer.Indexer;
-                    {
+                        break;
-                        _properSystemIndexer.Indexer = new SaveDataIndexer(FsClient, new U8Span(ProperSystemIndexerMountName),
+                    case SaveDataSpaceId.SafeMode:
-                            SaveDataSpaceId.ProperSystem, SaveDataId, MemoryResource);
+                        indexerLock = new UniqueLock(_safeIndexer.Locker);
 
-                        neededInit = true;
+                        if (!_safeIndexer.IsInitialized)
-                    }
+                        {
+                            _safeIndexer.Indexer = new SaveDataIndexer(FsClient, new U8Span(SafeModeIndexerMountName),
+                                SaveDataSpaceId.SafeMode, SaveDataId, MemoryResource);
 
-                    accessor = new SaveDataIndexerAccessor(_properSystemIndexer.Indexer, _properSystemIndexer.Locker);
+                            neededInit = true;
-                    return Result.Success;
+                        }
 
-                case SaveDataSpaceId.SafeMode:
+                        indexer = _safeIndexer.Indexer;
-                    Monitor.Enter(_safeIndexer.Locker);
+                        break;
 
-                    if (!_safeIndexer.IsInitialized)
+                    default:
-                    {
+                        accessor = default;
-                        _safeIndexer.Indexer = new SaveDataIndexer(FsClient, new U8Span(SafeModeIndexerMountName),
+                        return ResultFs.InvalidArgument.Log();
-                            SaveDataSpaceId.SafeMode, SaveDataId, MemoryResource);
+                }
 
-                        neededInit = true;
-                    }
 
-                    accessor = new SaveDataIndexerAccessor(_safeIndexer.Indexer, _safeIndexer.Locker);
+                accessor = new SaveDataIndexerAccessor(indexer, ref indexerLock);
-                    return Result.Success;
+                return Result.Success;
-
+            }
-                default:
+            finally
-                    accessor = default;
+            {
-                    return ResultFs.InvalidArgument.Log();
+                indexerLock.Dispose();
             }
         }
 
-        public void ResetTemporaryStorageIndexer(SaveDataSpaceId spaceId)
+        public void ResetIndexer(SaveDataSpaceId spaceId)
         {
             if (spaceId != SaveDataSpaceId.Temporary)
             {
@@ -156,7 +171,7 @@ namespace LibHac.FsSrv
             Assert.AssertTrue(rc.IsSuccess());
         }
 
-        public void InvalidateSdCardIndexer(SaveDataSpaceId spaceId)
+        public void InvalidateIndexer(SaveDataSpaceId spaceId)
         {
             // Note: Nintendo doesn't lock when doing this operation
             lock (_sdCardIndexer.Locker)
@@ -225,24 +240,17 @@ namespace LibHac.FsSrv
     public class SaveDataIndexerAccessor : IDisposable
     {
         public ISaveDataIndexer Indexer { get; }
-        private object Locker { get; }
+        private UniqueLock _locker;
-        private bool HasLock { get; set; }
 
-        public SaveDataIndexerAccessor(ISaveDataIndexer indexer, object locker)
+        public SaveDataIndexerAccessor(ISaveDataIndexer indexer, ref UniqueLock locker)
         {
             Indexer = indexer;
-            Locker = locker;
+            _locker = new UniqueLock(ref locker);
-            HasLock = true;
         }
 
         public void Dispose()
         {
-            if (HasLock)
+            _locker.Dispose();
-            {
-                Monitor.Exit(Locker);
-
-                HasLock = false;
-            }
         }
     }
 }

src/LibHac/FsSrv/SaveDataInfoFilterReader.cs

@@ -2,41 +2,45 @@
 using System.Runtime.InteropServices;
 using LibHac.Common;
 using LibHac.Fs;
+using LibHac.FsSrv.Sf;
 using LibHac.Ncm;
+using LibHac.Sf;
+using LibHac.Util;
 
 namespace LibHac.FsSrv
 {
-    internal class SaveDataInfoFilterReader : ISaveDataInfoReader
+    internal class SaveDataInfoFilterReader : SaveDataInfoReaderImpl, ISaveDataInfoReader
     {
-        private ReferenceCountedDisposable<ISaveDataInfoReader> Reader { get; }
+        private ReferenceCountedDisposable<SaveDataInfoReaderImpl> Reader { get; }
-        private SaveDataFilterInternal Filter { get; }
+        private SaveDataInfoFilter InfoFilter { get; }
 
-        public SaveDataInfoFilterReader(ReferenceCountedDisposable<ISaveDataInfoReader> reader, ref SaveDataFilterInternal filter)
+        public SaveDataInfoFilterReader(ReferenceCountedDisposable<SaveDataInfoReaderImpl> reader,
+            in SaveDataInfoFilter infoFilter)
         {
-            Reader = reader;
+            Reader = reader.AddReference();
-            Filter = filter;
+            InfoFilter = infoFilter;
         }
 
-        public Result Read(out long readCount, Span<byte> saveDataInfoBuffer)
+        public Result Read(out long readCount, OutBuffer saveDataInfoBuffer)
         {
             readCount = default;
 
-            Span<SaveDataInfo> outInfo = MemoryMarshal.Cast<byte, SaveDataInfo>(saveDataInfoBuffer);
+            Span<SaveDataInfo> outInfo = MemoryMarshal.Cast<byte, SaveDataInfo>(saveDataInfoBuffer.Buffer);
 
             SaveDataInfo tempInfo = default;
             Span<byte> tempInfoBytes = SpanHelpers.AsByteSpan(ref tempInfo);
 
-            ISaveDataInfoReader reader = Reader.Target;
+            SaveDataInfoReaderImpl reader = Reader.Target;
             int count = 0;
 
             while (count < outInfo.Length)
             {
-                Result rc = reader.Read(out long baseReadCount, tempInfoBytes);
+                Result rc = reader.Read(out long baseReadCount, new OutBuffer(tempInfoBytes));
                 if (rc.IsFailure()) return rc;
 
                 if (baseReadCount == 0) break;
 
-                if (Filter.Matches(ref tempInfo))
+                if (InfoFilter.Includes(in tempInfo))
                 {
                     outInfo[count] = tempInfo;
 
@@ -55,133 +59,97 @@ namespace LibHac.FsSrv
         }
     }
 
-    [StructLayout(LayoutKind.Explicit, Size = 0x50)]
+    [StructLayout(LayoutKind.Sequential, Size = 0x60)]
-    internal struct SaveDataFilterInternal
+    internal struct SaveDataInfoFilter
     {
-        [FieldOffset(0x00)] public bool FilterBySaveDataSpaceId;
+        public Optional<SaveDataSpaceId> SpaceId;
-        [FieldOffset(0x01)] public SaveDataSpaceId SpaceId;
+        public Optional<ProgramId> ProgramId;
+        public Optional<SaveDataType> SaveDataType;
+        public Optional<UserId> UserId;
+        public Optional<ulong> SaveDataId;
+        public Optional<ushort> Index;
+        public int Rank;
 
-        [FieldOffset(0x08)] public bool FilterByProgramId;
+        public SaveDataInfoFilter(in SaveDataInfoFilter filter)
-        [FieldOffset(0x10)] public ProgramId ProgramId;
-
-        [FieldOffset(0x18)] public bool FilterBySaveDataType;
-        [FieldOffset(0x19)] public SaveDataType SaveDataType;
-
-        [FieldOffset(0x20)] public bool FilterByUserId;
-        [FieldOffset(0x28)] public UserId UserId;
-
-        [FieldOffset(0x38)] public bool FilterBySaveDataId;
-        [FieldOffset(0x40)] public ulong SaveDataId;
-
-        [FieldOffset(0x48)] public bool FilterByIndex;
-        [FieldOffset(0x4A)] public short Index;
-
-        [FieldOffset(0x4C)] public int Rank;
-
-        public SaveDataFilterInternal(ref SaveDataFilter filter, SaveDataSpaceId spaceId)
         {
-            this = default;
+            this = filter;
+        }
 
-            FilterBySaveDataSpaceId = true;
+        public SaveDataInfoFilter(SaveDataSpaceId spaceId, in SaveDataFilter filter)
-            SpaceId = spaceId;
+        {
+            // Start out with no optional values
+            this = new SaveDataInfoFilter();
 
+            SpaceId = new Optional<SaveDataSpaceId>(spaceId);
             Rank = (int)filter.Rank;
 
             if (filter.FilterByProgramId)
             {
-                FilterByProgramId = true;
+                ProgramId = new Optional<ProgramId>(in filter.Attribute.ProgramId);
-                ProgramId = filter.ProgramId;
             }
 
             if (filter.FilterBySaveDataType)
             {
-                FilterBySaveDataType = true;
+                SaveDataType = new Optional<SaveDataType>(in filter.Attribute.Type);
-                SaveDataType = filter.SaveDataType;
             }
 
             if (filter.FilterByUserId)
             {
-                FilterByUserId = true;
+                UserId = new Optional<UserId>(in filter.Attribute.UserId);
-                UserId = filter.UserId;
             }
 
             if (filter.FilterBySaveDataId)
             {
-                FilterBySaveDataId = true;
+                SaveDataId = new Optional<ulong>(in filter.Attribute.StaticSaveDataId);
-                SaveDataId = filter.SaveDataId;
             }
 
             if (filter.FilterByIndex)
             {
-                FilterByIndex = true;
+                Index = new Optional<ushort>(in filter.Attribute.Index);
-                Index = filter.Index;
             }
         }
 
-        public void SetSaveDataSpaceId(SaveDataSpaceId spaceId)
+        public SaveDataInfoFilter(Optional<SaveDataSpaceId> spaceId, Optional<ProgramId> programId,
+            Optional<SaveDataType> saveDataType, Optional<UserId> userId, Optional<ulong> saveDataId,
+            Optional<ushort> index, int rank)
         {
-            FilterBySaveDataSpaceId = true;
             SpaceId = spaceId;
+            ProgramId = programId;
+            SaveDataType = saveDataType;
+            UserId = userId;
+            SaveDataId = saveDataId;
+            Index = index;
+            Rank = rank;
         }
 
-        public void SetProgramId(ProgramId value)
+        public bool Includes(in SaveDataInfo saveInfo)
         {
-            FilterByProgramId = true;
+            if (SpaceId.HasValue && saveInfo.SpaceId != SpaceId.Value)
-            ProgramId = value;
-        }
-
-        public void SetSaveDataType(SaveDataType value)
-        {
-            FilterBySaveDataType = true;
-            SaveDataType = value;
-        }
-
-        public void SetUserId(UserId value)
-        {
-            FilterByUserId = true;
-            UserId = value;
-        }
-
-        public void SetSaveDataId(ulong value)
-        {
-            FilterBySaveDataId = true;
-            SaveDataId = value;
-        }
-
-        public void SetIndex(short value)
-        {
-            FilterByIndex = true;
-            Index = value;
-        }
-
-        public bool Matches(ref SaveDataInfo info)
-        {
-            if (FilterBySaveDataSpaceId && info.SpaceId != SpaceId)
             {
                 return false;
             }
 
-            if (FilterByProgramId && info.ProgramId != ProgramId)
+            if (ProgramId.HasValue && saveInfo.ProgramId != ProgramId.Value)
             {
                 return false;
             }
 
-            if (FilterBySaveDataType && info.Type != SaveDataType)
+            if (SaveDataType.HasValue && saveInfo.Type != SaveDataType.Value)
             {
                 return false;
             }
 
-            if (FilterByUserId && info.UserId != UserId)
+            if (UserId.HasValue && saveInfo.UserId != UserId.Value)
             {
                 return false;
             }
 
-            if (FilterBySaveDataId && info.SaveDataId != SaveDataId)
+            if (SaveDataId.HasValue && saveInfo.SaveDataId != SaveDataId.Value)
             {
                 return false;
             }
 
-            if (FilterByIndex && info.Index != Index)
+            if (Index.HasValue && saveInfo.Index != Index.Value)
             {
                 return false;
             }
@@ -189,7 +157,7 @@ namespace LibHac.FsSrv
             var filterRank = (SaveDataRank)(Rank & 1);
 
             // When filtering by secondary rank, match on both primary and secondary ranks
-            if (filterRank == SaveDataRank.Primary && info.Rank == SaveDataRank.Secondary)
+            if (filterRank == SaveDataRank.Primary && saveInfo.Rank == SaveDataRank.Secondary)
             {
                 return false;
             }

src/LibHac/FsSrv/SaveDataInfoReaderImpl.cs

@@ -0,0 +1,28 @@
+using System;
+using LibHac.Fs;
+using LibHac.Sf;
+
+namespace LibHac.FsSrv
+{
+    /// <summary>
+    /// Iterates through the <see cref="SaveDataInfo"/> of the save data
+    /// in a single save data space.
+    /// </summary>
+    // ReSharper disable once InconsistentNaming
+    // Kinda weird to name an interface / pure abstract class SaveDataInfoReaderImpl. Ask Nintendo, not me.
+    //
+    public interface SaveDataInfoReaderImpl : IDisposable
+    {
+        /// <summary>
+        /// Returns the next <see cref="SaveDataInfo"/> entries. This method will continue writing
+        /// entries to <paramref name="saveDataInfoBuffer"/> until there is either no more space
+        /// in the buffer, or until there are no more entries to iterate.
+        /// </summary>
+        /// <param name="readCount">If the method returns successfully, contains the number
+        /// of <see cref="SaveDataInfo"/> written to <paramref name="saveDataInfoBuffer"/>.
+        /// A value of 0 indicates that there are no more entries to iterate, or the buffer is too small.</param>
+        /// <param name="saveDataInfoBuffer">The buffer in which to write the <see cref="SaveDataInfo"/>.</param>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        Result Read(out long readCount, OutBuffer saveDataInfoBuffer);
+    }
+}

src/LibHac/FsSrv/SaveDataTransferCryptoConfiguration.cs

@@ -0,0 +1,35 @@
+using System;
+using LibHac.Crypto;
+
+namespace LibHac.FsSrv
+{
+    public class SaveDataTransferCryptoConfiguration
+    {
+        private Data100 _tokenSigningKeyModulus;
+        private Data100 _keySeedPackageSigningKeyModulus;
+        private Data100 _kekEncryptionKeyModulus;
+        private Data100 _keyPackageSigningModulus;
+
+        public Span<byte> TokenSigningKeyModulus => _tokenSigningKeyModulus.Data;
+        public Span<byte> KeySeedPackageSigningKeyModulus => _keySeedPackageSigningKeyModulus.Data;
+        public Span<byte> KekEncryptionKeyModulus => _kekEncryptionKeyModulus.Data;
+        public Span<byte> KeyPackageSigningModulus => _keyPackageSigningModulus.Data;
+
+        public SaveTransferAesKeyGenerator GenerateAesKey { get; set; }
+        public RandomDataGenerator GenerateRandomData { get; set; }
+        public SaveTransferCmacGenerator GenerateCmac { get; set; }
+
+        public enum KeyIndex
+        {
+            SaveDataTransferToken,
+            SaveDataTransfer,
+            SaveDataTransferKeySeedPackage,
+            CloudBackUpInitialData,
+            CloudBackUpImportContext,
+            CloudBackUpInitialDataMac,
+            SaveDataRepairKeyPackage,
+            SaveDataRepairInitialDataMacBeforeRepair,
+            SaveDataRepairInitialDataMacAfterRepair
+        }
+    }
+}

src/LibHac/FsSrv/Sf/IMultiCommitManager.cs

@@ -0,0 +1,10 @@
+using System;
+
+namespace LibHac.FsSrv.Sf
+{
+    public interface IMultiCommitManager : IDisposable
+    {
+        Result Add(ReferenceCountedDisposable<IFileSystemSf> fileSystem);
+        Result Commit();
+    }
+}

src/LibHac/FsSrv/Sf/ISaveDataInfoReader.cs

@@ -1,7 +1,8 @@
 using System;
 using LibHac.Fs;
+using LibHac.Sf;
 
-namespace LibHac.FsSrv
+namespace LibHac.FsSrv.Sf
 {
     /// <summary>
     /// Iterates through the <see cref="SaveDataInfo"/> of the save data
@@ -19,6 +20,6 @@ namespace LibHac.FsSrv
         /// A value of 0 indicates that there are no more entries to iterate, or the buffer is too small.</param>
         /// <param name="saveDataInfoBuffer">The buffer in which to write the <see cref="SaveDataInfo"/>.</param>
         /// <returns>The <see cref="Result"/> of the operation.</returns>
-        Result Read(out long readCount, Span<byte> saveDataInfoBuffer);
+        Result Read(out long readCount, OutBuffer saveDataInfoBuffer);
     }
-}
+}

src/LibHac/FsSrv/Sf/ISaveDataMover.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace LibHac.FsSrv.Sf
+{
+    public interface ISaveDataMover : IDisposable
+    {
+        Result Register(ulong saveDataId);
+        Result Process(out long remainingSize, long sizeToProcess);
+        Result Cancel();
+    }
+}

src/LibHac/FsSrv/Util.cs

@@ -47,7 +47,7 @@ namespace LibHac.FsSrv
 
         public static Result VerifyHostPath(U8Span path)
         {
-            if(path.IsEmpty())
+            if (path.IsEmpty())
                 return Result.Success;
 
             if (path[0] != StringTraits.DirectorySeparator)
@@ -55,7 +55,7 @@ namespace LibHac.FsSrv
 
             U8Span path2 = path.Slice(1);
 
-            if(path2.IsEmpty())
+            if (path2.IsEmpty())
                 return Result.Success;
 
             int skipLength = PathUtility.GetWindowsPathSkipLength(path2);

src/LibHac/FsSystem/AesXtsFileSystem.cs

@@ -11,14 +11,16 @@ namespace LibHac.FsSystem
         public int BlockSize { get; }
 
         private IFileSystem BaseFileSystem { get; }
+        private ReferenceCountedDisposable<IFileSystem> SharedBaseFileSystem { get; }
         private byte[] KekSource { get; }
         private byte[] ValidationKey { get; }
 
-        public AesXtsFileSystem(IFileSystem fs, byte[] kekSource, byte[] validationKey, int blockSize)
+        public AesXtsFileSystem(ReferenceCountedDisposable<IFileSystem> fs, byte[] keys, int blockSize)
         {
-            BaseFileSystem = fs;
+            SharedBaseFileSystem = fs.AddReference();
-            KekSource = kekSource;
+            BaseFileSystem = SharedBaseFileSystem.Target;
-            ValidationKey = validationKey;
+            KekSource = keys.AsSpan(0, 0x10).ToArray();
+            ValidationKey = keys.AsSpan(0x10, 0x10).ToArray();
             BlockSize = blockSize;
         }
 
@@ -30,6 +32,16 @@ namespace LibHac.FsSystem
             BlockSize = blockSize;
         }
 
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                SharedBaseFileSystem?.Dispose();
+            }
+
+            base.Dispose(disposing);
+        }
+
         protected override Result DoCreateDirectory(U8Span path)
         {
             return BaseFileSystem.CreateDirectory(path);

src/LibHac/FsSystem/ApplicationTemporaryFileSystem.cs

@@ -0,0 +1,90 @@
+using System;
+using LibHac.Common;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+
+namespace LibHac.FsSystem
+{
+    public class ApplicationTemporaryFileSystem : IFileSystem, ISaveDataExtraDataAccessor
+    {
+        protected override Result DoCreateFile(U8Span path, long size, CreateFileOptions option)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoDeleteFile(U8Span path)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoCreateDirectory(U8Span path)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoDeleteDirectory(U8Span path)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoDeleteDirectoryRecursively(U8Span path)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoCleanDirectoryRecursively(U8Span path)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoRenameFile(U8Span oldPath, U8Span newPath)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoRenameDirectory(U8Span oldPath, U8Span newPath)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoGetEntryType(out DirectoryEntryType entryType, U8Span path)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoOpenFile(out IFile file, U8Span path, OpenMode mode)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoOpenDirectory(out IDirectory directory, U8Span path, OpenDirectoryMode mode)
+        {
+            throw new NotImplementedException();
+        }
+
+        protected override Result DoCommit()
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result WriteExtraData(in SaveDataExtraData extraData)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result CommitExtraData(bool updateTimeStamp)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Result ReadExtraData(out SaveDataExtraData extraData)
+        {
+            throw new NotImplementedException();
+        }
+
+        public void RegisterCacheObserver(ISaveDataExtraDataAccessorCacheObserver observer, SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

src/LibHac/FsSystem/ForwardingFileSystem.cs

@@ -0,0 +1,83 @@
+using System;
+using LibHac.Common;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+
+namespace LibHac.FsSystem
+{
+    public class ForwardingFileSystem : IFileSystem
+    {
+        private ReferenceCountedDisposable<IFileSystem> BaseFileSystem { get; set; }
+
+        public ForwardingFileSystem(ReferenceCountedDisposable<IFileSystem> baseFileSystem)
+        {
+            BaseFileSystem = baseFileSystem.AddReference();
+        }
+
+        protected ForwardingFileSystem(ref ReferenceCountedDisposable<IFileSystem> baseFileSystem)
+        {
+            BaseFileSystem = Shared.Move(ref baseFileSystem);
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                BaseFileSystem?.Dispose();
+            }
+
+            base.Dispose(disposing);
+        }
+
+        protected override Result DoCreateFile(U8Span path, long size, CreateFileOptions option) =>
+            BaseFileSystem.Target.CreateFile(path, size, option);
+
+        protected override Result DoDeleteFile(U8Span path) => BaseFileSystem.Target.DeleteFile(path);
+
+        protected override Result DoCreateDirectory(U8Span path) => BaseFileSystem.Target.CreateDirectory(path);
+
+        protected override Result DoDeleteDirectory(U8Span path) => BaseFileSystem.Target.DeleteDirectory(path);
+
+        protected override Result DoDeleteDirectoryRecursively(U8Span path) =>
+            BaseFileSystem.Target.DeleteDirectoryRecursively(path);
+
+        protected override Result DoCleanDirectoryRecursively(U8Span path) =>
+            BaseFileSystem.Target.CleanDirectoryRecursively(path);
+
+        protected override Result DoRenameFile(U8Span oldPath, U8Span newPath) =>
+            BaseFileSystem.Target.RenameFile(oldPath, newPath);
+
+        protected override Result DoRenameDirectory(U8Span oldPath, U8Span newPath) =>
+            BaseFileSystem.Target.RenameDirectory(oldPath, newPath);
+
+        protected override Result DoGetEntryType(out DirectoryEntryType entryType, U8Span path) =>
+            BaseFileSystem.Target.GetEntryType(out entryType, path);
+
+        protected override Result DoGetFreeSpaceSize(out long freeSpace, U8Span path) =>
+            BaseFileSystem.Target.GetFreeSpaceSize(out freeSpace, path);
+
+        protected override Result DoGetTotalSpaceSize(out long totalSpace, U8Span path) =>
+            BaseFileSystem.Target.GetTotalSpaceSize(out totalSpace, path);
+
+        protected override Result DoOpenFile(out IFile file, U8Span path, OpenMode mode) =>
+            BaseFileSystem.Target.OpenFile(out file, path, mode);
+
+        protected override Result DoOpenDirectory(out IDirectory directory, U8Span path, OpenDirectoryMode mode) =>
+            BaseFileSystem.Target.OpenDirectory(out directory, path, mode);
+
+        protected override Result DoCommit() => BaseFileSystem.Target.Commit();
+
+        protected override Result DoCommitProvisionally(long counter) =>
+            BaseFileSystem.Target.CommitProvisionally(counter);
+
+        protected override Result DoRollback() => BaseFileSystem.Target.Rollback();
+
+        protected override Result DoFlush() => BaseFileSystem.Target.Flush();
+
+        protected override Result DoGetFileTimeStampRaw(out FileTimeStampRaw timeStamp, U8Span path) =>
+            BaseFileSystem.Target.GetFileTimeStampRaw(out timeStamp, path);
+
+        protected override Result DoQueryEntry(Span<byte> outBuffer, ReadOnlySpan<byte> inBuffer, QueryId queryId,
+            U8Span path) => BaseFileSystem.Target.QueryEntry(outBuffer, inBuffer, queryId, path);
+    }
+}

src/LibHac/FsSystem/ISaveDataExtraDataAccessor.cs

@@ -0,0 +1,13 @@
+using System;
+using LibHac.Fs;
+
+namespace LibHac.FsSystem
+{
+    public interface ISaveDataExtraDataAccessor : IDisposable
+    {
+        Result WriteExtraData(in SaveDataExtraData extraData);
+        Result CommitExtraData(bool updateTimeStamp);
+        Result ReadExtraData(out SaveDataExtraData extraData);
+        void RegisterCacheObserver(ISaveDataExtraDataAccessorCacheObserver observer, SaveDataSpaceId spaceId, ulong saveDataId);
+    }
+}

src/LibHac/FsSystem/ISaveDataExtraDataAccessorCacheObserver.cs

@@ -0,0 +1,10 @@
+using System;
+using LibHac.Fs;
+
+namespace LibHac.FsSystem
+{
+    public interface ISaveDataExtraDataAccessorCacheObserver : IDisposable
+    {
+        void Unregister(SaveDataSpaceId spaceId, ulong saveDataId);
+    }
+}

src/LibHac/FsSystem/ISaveDataFileSystemCacheManager.cs

@@ -0,0 +1,14 @@
+using System;
+using LibHac.Fs;
+using LibHac.FsSystem.Save;
+
+namespace LibHac.FsSystem
+{
+    public interface ISaveDataFileSystemCacheManager : IDisposable
+    {
+        bool GetCache(out ReferenceCountedDisposable<SaveDataFileSystem> fileSystem, SaveDataSpaceId spaceId, ulong saveDataId);
+        void Register(ReferenceCountedDisposable<ApplicationTemporaryFileSystem> fileSystem);
+        void Register(ReferenceCountedDisposable<SaveDataFileSystem> fileSystem);
+        void Unregister(SaveDataSpaceId spaceId, ulong saveDataId);
+    }
+}

src/LibHac/FsSystem/IUniqueLock.cs

@@ -1,8 +0,0 @@
-using System;
-
-namespace LibHac.FsSystem
-{
-    public interface IUniqueLock : IDisposable
-    {
-    }
-}

src/LibHac/FsSystem/ReadOnlyFileSystem.cs

@@ -21,6 +21,13 @@ namespace LibHac.FsSystem
             BaseFs = BaseFsShared.Target;
         }
 
+        public static ReferenceCountedDisposable<IFileSystem> CreateShared(
+            ref ReferenceCountedDisposable<IFileSystem> baseFileSystem)
+        {
+            var fs = new ReadOnlyFileSystem(Shared.Move(ref baseFileSystem));
+            return new ReferenceCountedDisposable<IFileSystem>(fs);
+        }
+
         protected override Result DoOpenDirectory(out IDirectory directory, U8Span path, OpenDirectoryMode mode)
         {
             return BaseFs.OpenDirectory(out directory, path, mode);

src/LibHac/FsSystem/Save/ISaveDataExtraDataAccessor.cs

@@ -1,9 +0,0 @@
-namespace LibHac.FsSystem.Save
-{
-    public interface ISaveDataExtraDataAccessor
-    {
-        Result Write(ExtraData data);
-        Result Commit();
-        Result Read(out ExtraData data);
-    }
-}

src/LibHac/FsSystem/Save/SaveDataFileSystem.cs

@@ -72,7 +72,7 @@ namespace LibHac.FsSystem.Save
                 MapStorage = MetaRemapStorage.Slice(layout.JournalMapTableOffset, layout.JournalMapTableSize),
                 PhysicalBlockBitmap = MetaRemapStorage.Slice(layout.JournalPhysicalBitmapOffset, layout.JournalPhysicalBitmapSize),
                 VirtualBlockBitmap = MetaRemapStorage.Slice(layout.JournalVirtualBitmapOffset, layout.JournalVirtualBitmapSize),
-                FreeBlockBitmap = MetaRemapStorage.Slice(layout.JournalFreeBitmapOffset, layout.JournalFreeBitmapSize),
+                FreeBlockBitmap = MetaRemapStorage.Slice(layout.JournalFreeBitmapOffset, layout.JournalFreeBitmapSize)
             };
 
             IStorage journalData = DataRemapStorage.Slice(layout.JournalDataOffset,

src/LibHac/FsSystem/StorageLayoutTypeSetFileSystem.cs

@@ -0,0 +1,165 @@
+using System;
+using LibHac.Common;
+using LibHac.Fs;
+using LibHac.Fs.Fsa;
+
+namespace LibHac.FsSystem
+{
+    internal class StorageLayoutTypeSetFileSystem : IFileSystem
+    {
+        private ReferenceCountedDisposable<IFileSystem> BaseFileSystem { get; }
+        private StorageType StorageFlag { get; }
+
+        public StorageLayoutTypeSetFileSystem(ReferenceCountedDisposable<IFileSystem> baseFileSystem,
+            StorageType storageFlag)
+        {
+            BaseFileSystem = baseFileSystem.AddReference();
+            StorageFlag = storageFlag;
+        }
+
+        protected StorageLayoutTypeSetFileSystem(ref ReferenceCountedDisposable<IFileSystem> baseFileSystem,
+            StorageType storageFlag)
+        {
+            BaseFileSystem = Shared.Move(ref baseFileSystem);
+            StorageFlag = storageFlag;
+        }
+
+        public static ReferenceCountedDisposable<IFileSystem> CreateShared(
+            ReferenceCountedDisposable<IFileSystem> baseFileSystem, StorageType storageFlag)
+        {
+            return new ReferenceCountedDisposable<IFileSystem>(
+                new StorageLayoutTypeSetFileSystem(baseFileSystem, storageFlag));
+        }
+
+        public static ReferenceCountedDisposable<IFileSystem> CreateShared(
+            ref ReferenceCountedDisposable<IFileSystem> baseFileSystem, StorageType storageFlag)
+        {
+            return new ReferenceCountedDisposable<IFileSystem>(
+                new StorageLayoutTypeSetFileSystem(ref baseFileSystem, storageFlag));
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                BaseFileSystem?.Dispose();
+            }
+
+            base.Dispose(disposing);
+        }
+
+        protected override Result DoCreateFile(U8Span path, long size, CreateFileOptions option)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.CreateFile(path, size, option);
+        }
+
+        protected override Result DoDeleteFile(U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.DeleteFile(path);
+        }
+
+        protected override Result DoCreateDirectory(U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.CreateDirectory(path);
+        }
+
+        protected override Result DoDeleteDirectory(U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.DeleteDirectory(path);
+        }
+
+        protected override Result DoDeleteDirectoryRecursively(U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.DeleteDirectoryRecursively(path);
+        }
+
+        protected override Result DoCleanDirectoryRecursively(U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.CleanDirectoryRecursively(path);
+        }
+
+        protected override Result DoRenameFile(U8Span oldPath, U8Span newPath)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.RenameFile(oldPath, newPath);
+        }
+
+        protected override Result DoRenameDirectory(U8Span oldPath, U8Span newPath)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.RenameDirectory(oldPath, newPath);
+        }
+
+        protected override Result DoGetEntryType(out DirectoryEntryType entryType, U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.GetEntryType(out entryType, path);
+        }
+
+        protected override Result DoGetFreeSpaceSize(out long freeSpace, U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.GetFreeSpaceSize(out freeSpace, path);
+        }
+
+        protected override Result DoGetTotalSpaceSize(out long totalSpace, U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.GetTotalSpaceSize(out totalSpace, path);
+        }
+
+        protected override Result DoOpenFile(out IFile file, U8Span path, OpenMode mode)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.OpenFile(out file, path, mode);
+        }
+
+        protected override Result DoOpenDirectory(out IDirectory directory, U8Span path, OpenDirectoryMode mode)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.OpenDirectory(out directory, path, mode);
+        }
+
+        protected override Result DoCommit()
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.Commit();
+        }
+
+        protected override Result DoCommitProvisionally(long counter)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.CommitProvisionally(counter);
+        }
+
+        protected override Result DoRollback()
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.Rollback();
+        }
+
+        protected override Result DoFlush()
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.Flush();
+        }
+
+        protected override Result DoGetFileTimeStampRaw(out FileTimeStampRaw timeStamp, U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.GetFileTimeStampRaw(out timeStamp, path);
+        }
+
+        protected override Result DoQueryEntry(Span<byte> outBuffer, ReadOnlySpan<byte> inBuffer, QueryId queryId, U8Span path)
+        {
+            using var scopedLayoutType = new ScopedStorageLayoutTypeSetter(StorageFlag);
+            return BaseFileSystem.Target.QueryEntry(outBuffer, inBuffer, queryId, path);
+        }
+    }
+}

src/LibHac/FsSystem/StorageLayoutTypeSetter.cs

@@ -0,0 +1,30 @@
+using System;
+
+namespace LibHac.FsSystem
+{
+    internal struct ScopedStorageLayoutTypeSetter : IDisposable
+    {
+        // ReSharper disable once UnusedParameter.Local
+        public ScopedStorageLayoutTypeSetter(StorageType storageFlag)
+        {
+            // Todo: Implement
+        }
+
+        public void Dispose()
+        {
+
+        }
+    }
+
+    [Flags]
+    internal enum StorageType
+    {
+        Bis = 1 << 0,
+        SdCard = 1 << 1,
+        GameCard = 1 << 2,
+        Usb = 1 << 3,
+
+        NonGameCard = Bis | SdCard | Usb,
+        All = Bis | SdCard | GameCard | Usb
+    }
+}

src/LibHac/FsSystem/UniqueLockSemaphore.cs

@@ -0,0 +1,97 @@
+using System;
+using System.Threading;
+using LibHac.Common;
+using LibHac.Diag;
+
+namespace LibHac.FsSystem
+{
+    public interface IUniqueLock : IDisposable
+    {
+    }
+
+    /// <summary>
+    /// Represents a lock that may be passed between functions or objects.
+    /// </summary>
+    /// <remarks>This struct must never be copied. It must always be passed by
+    /// reference or moved via the move constructor.</remarks>
+    public struct UniqueLockSemaphore : IDisposable
+    {
+        private SemaphoreAdaptor _semaphore;
+        private bool _isLocked;
+
+        public UniqueLockSemaphore(SemaphoreAdaptor semaphore)
+        {
+            _semaphore = semaphore;
+            _isLocked = false;
+        }
+
+        public UniqueLockSemaphore(ref UniqueLockSemaphore other)
+        {
+            _semaphore = other._semaphore;
+            _isLocked = other._isLocked;
+
+            other._isLocked = false;
+            other._semaphore = null;
+        }
+
+        public bool IsLocked => _isLocked;
+
+        public bool TryLock()
+        {
+            if (_isLocked)
+            {
+                throw new SynchronizationLockException("Attempted to lock a UniqueLock that was already locked.");
+            }
+
+            _isLocked = _semaphore.TryLock();
+            return _isLocked;
+        }
+
+        public void Unlock()
+        {
+            if (!_isLocked)
+            {
+                throw new SynchronizationLockException("Attempted to unlock a UniqueLock that was not locked.");
+            }
+
+            _semaphore.Unlock();
+            _isLocked = false;
+        }
+
+        public void Dispose()
+        {
+            if (_isLocked)
+            {
+                _semaphore.Unlock();
+
+                _isLocked = false;
+                _semaphore = null;
+            }
+        }
+    }
+
+    public class UniqueLockWithPin<T> : IUniqueLock where T : class, IDisposable
+    {
+        private UniqueLockSemaphore _semaphore;
+        private ReferenceCountedDisposable<T> _pinnedObject;
+
+        public UniqueLockWithPin(ref UniqueLockSemaphore semaphore, ref ReferenceCountedDisposable<T> pinnedObject)
+        {
+            Shared.Move(out _semaphore, ref semaphore);
+            Shared.Move(out _pinnedObject, ref pinnedObject);
+
+            Assert.AssertTrue(_semaphore.IsLocked);
+        }
+
+        public void Dispose()
+        {
+            if (_pinnedObject != null)
+            {
+                _semaphore.Dispose();
+                _pinnedObject.Dispose();
+
+                _pinnedObject = null;
+            }
+        }
+    }
+}

src/LibHac/FsSystem/Utility.cs

@@ -226,6 +226,48 @@ namespace LibHac.FsSystem
             return Result.Success;
         }
 
+        public static Result TryAcquireCountSemaphore(out UniqueLockSemaphore uniqueLock, SemaphoreAdaptor semaphore)
+        {
+            UniqueLockSemaphore tempUniqueLock = default;
+            try
+            {
+                tempUniqueLock = new UniqueLockSemaphore(semaphore);
+
+                if (!tempUniqueLock.TryLock())
+                {
+                    uniqueLock = default;
+                    return ResultFs.OpenCountLimit.Log();
+                }
+
+                uniqueLock = new UniqueLockSemaphore(ref tempUniqueLock);
+                return Result.Success;
+            }
+            finally
+            {
+                tempUniqueLock.Dispose();
+            }
+        }
+
+        public static Result MakeUniqueLockWithPin<T>(out IUniqueLock uniqueLock, SemaphoreAdaptor semaphore,
+            ref ReferenceCountedDisposable<T> objectToPin) where T : class, IDisposable
+        {
+            uniqueLock = default;
+
+            UniqueLockSemaphore tempUniqueLock = default;
+            try
+            {
+                Result rc = TryAcquireCountSemaphore(out tempUniqueLock, semaphore);
+                if (rc.IsFailure()) return rc;
+
+                uniqueLock = new UniqueLockWithPin<T>(ref tempUniqueLock, ref objectToPin);
+                return Result.Success;
+            }
+            finally
+            {
+                tempUniqueLock.Dispose();
+            }
+        }
+
         public static Result RetryFinitelyForTargetLocked(Func<Result> function)
         {
             const int maxRetryCount = 10;

src/LibHac/Ncm/ContentMetaId.cs

@@ -1,6 +1,8 @@
-namespace LibHac.Ncm
+using System;
+
+namespace LibHac.Ncm
 {
-    public readonly struct ApplicationId
+    public readonly struct ApplicationId : IEquatable<ApplicationId>
     {
         public readonly ulong Value;
 
@@ -20,6 +22,13 @@
         {
             return Start <= programId && programId <= End;
         }
+
+        public bool Equals(ApplicationId other) => Value == other.Value;
+        public override bool Equals(object obj) => obj is ApplicationId id && Equals(id);
+        public override int GetHashCode() => Value.GetHashCode();
+
+        public static bool operator ==(ApplicationId left, ApplicationId right) => left.Equals(right);
+        public static bool operator !=(ApplicationId left, ApplicationId right) => !left.Equals(right);
     }
 
     public readonly struct PatchId

src/LibHac/ReferenceCountedDisposable.cs

@@ -441,6 +441,24 @@ namespace LibHac
 
                 return TryAddReferenceImpl(target, referenceCount);
             }
+
+            /// <summary>
+            /// Increments the reference count for the disposable object, and returns a new disposable reference to
+            /// it.
+            /// </summary>
+            /// <remarks>
+            /// <para>Unlike <see cref="ReferenceCountedDisposable{T}.TryAddReference"/>, this method is capable of
+            /// adding a reference to the underlying instance all the way up to the point where it is finally
+            /// disposed.</para>
+            ///
+            /// <para>The returned object is an independent reference to the same underlying object. Disposing of
+            /// the returned value multiple times will only cause the reference count to be decreased once.</para>
+            /// </remarks>
+            /// <returns>A new <see cref="ReferenceCountedDisposable{T}"/> pointing to the same underlying object,
+            /// if it has not yet been disposed; otherwise, <see cref="ObjectDisposedException"/> is thrown if the
+            /// underlying object has already been disposed.</returns>
+            public ReferenceCountedDisposable<T> AddReference() =>
+                TryAddReference() ?? throw new ObjectDisposedException(nameof(WeakReference));
         }
     }
 }

src/LibHac/Sf/Buffers.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Runtime.CompilerServices;
+using LibHac.Common;
+
+namespace LibHac.Sf
+{
+    public readonly ref struct InBuffer
+    {
+        private readonly ReadOnlySpan<byte> _buffer;
+
+        public int Size => _buffer.Length;
+        public ReadOnlySpan<byte> Buffer => _buffer;
+
+        public InBuffer(ReadOnlySpan<byte> buffer)
+        {
+            _buffer = buffer;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static InBuffer FromStruct<T>(in T value) where T : unmanaged
+        {
+            return new InBuffer(SpanHelpers.AsReadOnlyByteSpan(in value));
+        }
+    }
+
+    public readonly ref struct OutBuffer
+    {
+        private readonly Span<byte> _buffer;
+
+        public int Size => _buffer.Length;
+        public Span<byte> Buffer => _buffer;
+
+        public OutBuffer(Span<byte> buffer)
+        {
+            _buffer = buffer;
+        }
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static OutBuffer FromStruct<T>(ref T value) where T : unmanaged
+        {
+            return new OutBuffer(SpanHelpers.AsByteSpan(ref value));
+        }
+    }
+}

src/LibHac/Util/Impl/HexConverter.cs

@@ -20,7 +20,7 @@ namespace LibHac.Util.Impl
             // while outputs in the range [ 0x41 .. 0x46 ] ([ 'A' .. 'F' ])
             // don't have the 0x20 bit set, so ORing them maps to
             // [ 0x61 .. 0x66 ] ([ 'a' .. 'f' ]), which is what we want.
-            Lower = 0x2020U,
+            Lower = 0x2020U
         }
 
         // We want to pack the incoming byte into a single integer [ 0000 HHHH 0000 LLLL ],

src/LibHac/Util/Optional.cs

@@ -1,4 +1,5 @@
 using System.Runtime.InteropServices;
+using LibHac.Common;
 using LibHac.Diag;
 
 namespace LibHac.Util
@@ -8,7 +9,7 @@ namespace LibHac.Util
         private bool _hasValue;
         private T _value;
 
-        public bool HasValue => _hasValue;
+        public readonly bool HasValue => _hasValue;
         public ref T Value
         {
             get
@@ -18,6 +19,22 @@ namespace LibHac.Util
                 return ref MemoryMarshal.CreateSpan(ref _value, 1)[0];
             }
         }
+        public readonly ref readonly T ValueRo
+        {
+            get
+            {
+                Assert.AssertTrue(_hasValue);
+                return ref SpanHelpers.CreateReadOnlySpan(in _value, 1)[0];
+            }
+        }
+
+        public Optional(in T value)
+        {
+            _value = value;
+            _hasValue = true;
+        }
+
+        public static implicit operator Optional<T>(in T value) => new Optional<T>(in value);
 
         public void Set(in T value)
         {

src/LibHac/Util/UniqueLock.cs

@@ -0,0 +1,71 @@
+using System;
+using System.Threading;
+
+namespace LibHac.Util
+{
+    /// <summary>
+    /// Represents a lock that may be passed between functions or objects.
+    /// </summary>
+    /// <remarks>This struct must never be copied. It must always be passed by
+    /// reference or moved via the move constructor.</remarks>
+    public struct UniqueLock : IDisposable
+    {
+        private object _lockObject;
+        private bool _isLocked;
+
+        /// <summary>
+        /// Creates a new <see cref="UniqueLock"/> from the provided object and acquires the lock.
+        /// </summary>
+        /// <param name="lockObject">The object to lock.</param>
+        public UniqueLock(object lockObject)
+        {
+            _lockObject = lockObject;
+            _isLocked = false;
+
+            Lock();
+        }
+
+        public UniqueLock(ref UniqueLock other)
+        {
+            _lockObject = other._lockObject;
+            _isLocked = other._isLocked;
+
+            other._isLocked = false;
+            other._lockObject = null;
+        }
+
+        public bool IsLocked => _isLocked;
+
+        public void Lock()
+        {
+            if (_isLocked)
+            {
+                throw new SynchronizationLockException("Attempted to lock a UniqueLock that was already locked.");
+            }
+
+            Monitor.Enter(_lockObject, ref _isLocked);
+        }
+
+        public void Unlock()
+        {
+            if (!_isLocked)
+            {
+                throw new SynchronizationLockException("Attempted to unlock a UniqueLock that was not locked.");
+            }
+
+            Monitor.Exit(_lockObject);
+            _isLocked = false;
+        }
+
+        public void Dispose()
+        {
+            if (_isLocked)
+            {
+                Monitor.Exit(_lockObject);
+
+                _isLocked = false;
+                _lockObject = null;
+            }
+        }
+    }
+}

src/hactoolnet/Program.cs

@@ -14,7 +14,13 @@ namespace hactoolnet
         {
             try
             {
-                if (Run(args)) return 0;
+                if (Run(args))
+                {
+                   // Console.ReadKey();
+                    return 0;
+                }
+
+
             }
             catch (MissingKeyException ex)
             {

tests/LibHac.Tests/Fs/FileSystemClientTests/ApplicationSaveDataManagementTests.cs

@@ -60,7 +60,7 @@ namespace LibHac.Tests.Fs.FileSystemClientTests
 
             Assert.Equal(1, entriesRead);
             Assert.Equal(applicationId, info[0].ProgramId);
-            Assert.Equal(UserId.Zero, info[0].UserId);
+            Assert.Equal(UserId.InvalidId, info[0].UserId);
             Assert.Equal(SaveDataType.Device, info[0].Type);
         }
 
@@ -86,7 +86,7 @@ namespace LibHac.Tests.Fs.FileSystemClientTests
 
             Assert.Equal(1, entriesRead);
             Assert.Equal(applicationId, info[0].ProgramId);
-            Assert.Equal(UserId.Zero, info[0].UserId);
+            Assert.Equal(UserId.InvalidId, info[0].UserId);
             Assert.Equal(SaveDataType.Bcat, info[0].Type);
         }
 
@@ -112,7 +112,7 @@ namespace LibHac.Tests.Fs.FileSystemClientTests
 
             Assert.Equal(1, entriesRead);
             Assert.Equal(applicationId, info[0].ProgramId);
-            Assert.Equal(UserId.Zero, info[0].UserId);
+            Assert.Equal(UserId.InvalidId, info[0].UserId);
             Assert.Equal(SaveDataType.Temporary, info[0].Type);
         }
 

tests/LibHac.Tests/Fs/FileSystemClientTests/ShimTests/SaveDataManagement.cs

@@ -80,8 +80,8 @@ namespace LibHac.Tests.Fs.FileSystemClientTests.ShimTests
             Assert.Equal(applicationId, info[0].ProgramId);
             Assert.Equal(applicationId, info[1].ProgramId);
 
-            var expectedIndexes = new short[] { 0, 1 };
+            var expectedIndexes = new ushort[] { 0, 1 };
-            short[] actualIndexes = info.Take(2).Select(x => x.Index).OrderBy(x => x).ToArray();
+            ushort[] actualIndexes = info.Take(2).Select(x => x.Index).OrderBy(x => x).ToArray();
 
             Assert.Equal(expectedIndexes, actualIndexes);
         }
@@ -294,7 +294,7 @@ namespace LibHac.Tests.Fs.FileSystemClientTests.ShimTests
                 for (int i = 1; i <= count; i++)
                 {
                     var applicationId = new Ncm.ApplicationId((uint)i);
-                    Result rc = fs.CreateSaveData(applicationId, UserId.Zero, 0, 0x4000, 0x4000, SaveDataFlags.None);
+                    Result rc = fs.CreateSaveData(applicationId, UserId.InvalidId, 0, 0x4000, 0x4000, SaveDataFlags.None);
                     if (rc.IsFailure()) return rc;
                 }
             }
@@ -305,7 +305,7 @@ namespace LibHac.Tests.Fs.FileSystemClientTests.ShimTests
                 for (int i = 1; i <= count; i++)
                 {
                     var applicationId = new Ncm.ApplicationId((uint)rng.Next());
-                    Result rc = fs.CreateSaveData(applicationId, UserId.Zero, 0, 0x4000, 0x4000, SaveDataFlags.None);
+                    Result rc = fs.CreateSaveData(applicationId, UserId.InvalidId, 0, 0x4000, 0x4000, SaveDataFlags.None);
                     if (rc.IsFailure()) return rc;
                 }
             }