diff --git a/src/LibHac/FsSrv/Impl/SaveDataExtraDataAccessorCacheManager.cs b/src/LibHac/FsSrv/Impl/SaveDataExtraDataAccessorCacheManager.cs
new file mode 100644
index 00000000..dabe0f0b
--- /dev/null
+++ b/src/LibHac/FsSrv/Impl/SaveDataExtraDataAccessorCacheManager.cs
@@ -0,0 +1,134 @@
+using System.Collections.Generic;
+using LibHac.Common;
+using LibHac.Fs;
+using LibHac.FsSystem;
+using LibHac.Os;
+
+namespace LibHac.FsSrv.Impl
+{
+    /// <summary>
+    /// Holds the <see cref="ISaveDataExtraDataAccessor"/>s for opened save data file systems.
+    /// </summary>
+    public class SaveDataExtraDataAccessorCacheManager : ISaveDataExtraDataAccessorCacheObserver
+    {
+        private struct Cache
+        {
+            private ReferenceCountedDisposable<ISaveDataExtraDataAccessor>.WeakReference _accessor;
+            private readonly SaveDataSpaceId _spaceId;
+            private readonly ulong _saveDataId;
+
+            public Cache(ReferenceCountedDisposable<ISaveDataExtraDataAccessor> accessor, SaveDataSpaceId spaceId,
+                ulong saveDataId)
+            {
+                _accessor = new ReferenceCountedDisposable<ISaveDataExtraDataAccessor>.WeakReference(accessor);
+                _spaceId = spaceId;
+                _saveDataId = saveDataId;
+            }
+
+            public bool Contains(SaveDataSpaceId spaceId, ulong saveDataId)
+            {
+                return _spaceId == spaceId && _saveDataId == saveDataId;
+            }
+
+            public ReferenceCountedDisposable<ISaveDataExtraDataAccessor> Lock()
+            {
+                return _accessor.TryAddReference();
+            }
+        }
+
+        private readonly LinkedList<Cache> _accessorList;
+        private SdkRecursiveMutex _mutex;
+
+        public SaveDataExtraDataAccessorCacheManager()
+        {
+            _accessorList = new LinkedList<Cache>();
+            _mutex = new SdkRecursiveMutex();
+        }
+
+        public void Dispose()
+        {
+            _accessorList.Clear();
+        }
+
+        public Result Register(ReferenceCountedDisposable<ISaveDataExtraDataAccessor> accessor,
+            SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            var cache = new Cache(accessor, spaceId, saveDataId);
+
+            using ScopedLock<SdkRecursiveMutex> scopedLock = ScopedLock.Lock(ref _mutex);
+
+            _accessorList.AddLast(cache);
+            return Result.Success;
+        }
+
+        public void Unregister(SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            using ScopedLock<SdkRecursiveMutex> scopedLock = ScopedLock.Lock(ref _mutex);
+
+            UnregisterImpl(spaceId, saveDataId);
+        }
+
+        private void UnregisterImpl(SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            LinkedListNode<Cache> currentNode = _accessorList.First;
+
+            while (currentNode is not null)
+            {
+                if (currentNode.ValueRef.Contains(spaceId, saveDataId))
+                {
+                    _accessorList.Remove(currentNode);
+                    return;
+                }
+
+                currentNode = currentNode.Next;
+            }
+        }
+
+        public Result GetCache(out ReferenceCountedDisposable<ISaveDataExtraDataAccessor> accessor,
+            SaveDataSpaceId spaceId, ulong saveDataId)
+        {
+            UnsafeHelpers.SkipParamInit(out accessor);
+
+            using ScopedLock<SdkRecursiveMutex> scopedLock = ScopedLock.Lock(ref _mutex);
+
+            LinkedListNode<Cache> currentNode = _accessorList.First;
+
+            while (true)
+            {
+                if (currentNode is null)
+                    return ResultFs.TargetNotFound.Log();
+
+                if (currentNode.ValueRef.Contains(spaceId, saveDataId))
+                    break;
+
+                currentNode = currentNode.Next;
+            }
+
+            ReferenceCountedDisposable<ISaveDataExtraDataAccessor> tempAccessor = null;
+            try
+            {
+                tempAccessor = currentNode.ValueRef.Lock();
+
+                // Return early if the accessor was already disposed
+                if (tempAccessor is null)
+                {
+                    // Note: Nintendo doesn't remove the accessor from the list in this case
+                    _accessorList.Remove(currentNode);
+                    return ResultFs.TargetNotFound.Log();
+                }
+
+                accessor = SaveDataExtraDataResultConvertAccessor.CreateShared(ref tempAccessor);
+                return Result.Success;
+            }
+            finally
+            {
+                tempAccessor?.Dispose();
+            }
+        }
+
+        public ScopedLock<SdkRecursiveMutex> GetScopedLock()
+        {
+            return new ScopedLock<SdkRecursiveMutex>(ref _mutex);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/LibHac/FsSrv/Impl/SaveDataResultConvertFileSystem.cs b/src/LibHac/FsSrv/Impl/SaveDataResultConvertFileSystem.cs
new file mode 100644
index 00000000..5649416f
--- /dev/null
+++ b/src/LibHac/FsSrv/Impl/SaveDataResultConvertFileSystem.cs
@@ -0,0 +1,179 @@
+using LibHac.Common;
+using LibHac.Diag;
+using LibHac.Fs;
+using LibHac.FsSystem;
+
+namespace LibHac.FsSrv.Impl
+{
+    public static class SaveDataResultConvert
+    {
+        private static Result ConvertCorruptedResult(Result result)
+        {
+            if (ResultFs.IntegrityVerificationStorageCorrupted.Includes(result))
+            {
+                if (ResultFs.IncorrectIntegrityVerificationMagic.Includes(result))
+                    return ResultFs.IncorrectSaveDataIntegrityVerificationMagic.Value;
+
+                if (ResultFs.InvalidZeroHash.Includes(result))
+                    return ResultFs.InvalidSaveDataZeroHash.Value;
+
+                if (ResultFs.NonRealDataVerificationFailed.Includes(result))
+                    return ResultFs.SaveDataNonRealDataVerificationFailed.Value;
+
+                if (ResultFs.ClearedRealDataVerificationFailed.Includes(result))
+                    return ResultFs.ClearedSaveDataRealDataVerificationFailed.Value;
+
+                if (ResultFs.UnclearedRealDataVerificationFailed.Includes(result))
+                    return ResultFs.UnclearedSaveDataRealDataVerificationFailed.Value;
+
+                Assert.SdkAssert(false);
+            }
+
+            if (ResultFs.HostFileSystemCorrupted.Includes(result))
+            {
+                if (ResultFs.HostEntryCorrupted.Includes(result))
+                    return ResultFs.SaveDataHostEntryCorrupted.Value;
+
+                if (ResultFs.HostFileDataCorrupted.Includes(result))
+                    return ResultFs.SaveDataHostFileDataCorrupted.Value;
+
+                if (ResultFs.HostFileCorrupted.Includes(result))
+                    return ResultFs.SaveDataHostFileCorrupted.Value;
+
+                if (ResultFs.InvalidHostHandle.Includes(result))
+                    return ResultFs.InvalidSaveDataHostHandle.Value;
+
+                Assert.SdkAssert(false);
+            }
+
+            if (ResultFs.DatabaseCorrupted.Includes(result))
+            {
+                if (ResultFs.InvalidAllocationTableBlock.Includes(result))
+                    return ResultFs.InvalidSaveDataAllocationTableBlock.Value;
+
+                if (ResultFs.InvalidKeyValueListElementIndex.Includes(result))
+                    return ResultFs.InvalidSaveDataKeyValueListElementIndex.Value;
+
+                if (ResultFs.AllocationTableIteratedRangeEntry.Includes(result))
+                    return ResultFs.SaveDataAllocationTableIteratedRangeEntry.Value;
+
+                if (ResultFs.InvalidAllocationTableOffset.Includes(result))
+                    return ResultFs.InvalidSaveDataAllocationTableOffset.Value;
+
+                if (ResultFs.InvalidAllocationTableBlockCount.Includes(result))
+                    return ResultFs.InvalidSaveDataAllocationTableBlockCount.Value;
+
+                if (ResultFs.InvalidKeyValueListEntryIndex.Includes(result))
+                    return ResultFs.InvalidSaveDataKeyValueListEntryIndex.Value;
+
+                if (ResultFs.InvalidBitmapIndex.Includes(result))
+                    return ResultFs.InvalidSaveDataBitmapIndex.Value;
+
+                Assert.SdkAssert(false);
+            }
+
+            if (ResultFs.ZeroBitmapFileCorrupted.Includes(result))
+            {
+                if (ResultFs.IncompleteBlockInZeroBitmapHashStorageFile.Includes(result))
+                    return ResultFs.IncompleteBlockInZeroBitmapHashStorageFileSaveData.Value;
+
+                Assert.SdkAssert(false);
+            }
+
+            return result;
+        }
+
+        public static Result ConvertSaveFsDriverPublicResult(Result result)
+        {
+            if (result.IsSuccess())
+                return result;
+
+            if (ResultFs.UnsupportedVersion.Includes(result))
+                return ResultFs.UnsupportedSaveDataVersion.Value;
+
+            if (ResultFs.IntegrityVerificationStorageCorrupted.Includes(result) ||
+                ResultFs.BuiltInStorageCorrupted.Includes(result) ||
+                ResultFs.HostFileSystemCorrupted.Includes(result) ||
+                ResultFs.DatabaseCorrupted.Includes(result) ||
+                ResultFs.ZeroBitmapFileCorrupted.Includes(result))
+            {
+                return ConvertCorruptedResult(result);
+            }
+
+            if (ResultFs.FatFileSystemCorrupted.Includes(result))
+                return result;
+
+            if (ResultFs.NotFound.Includes(result))
+                return ResultFs.PathNotFound.Value;
+
+            if (ResultFs.AllocationTableFull.Includes(result))
+                return ResultFs.UsableSpaceNotEnough.Value;
+
+            if (ResultFs.AlreadyExists.Includes(result))
+                return ResultFs.PathAlreadyExists.Value;
+
+            if (ResultFs.InvalidOffset.Includes(result))
+                return ResultFs.OutOfRange.Value;
+
+            if (ResultFs.IncompatiblePath.Includes(result) ||
+                ResultFs.FileNotFound.Includes(result))
+            {
+                return ResultFs.PathNotFound.Value;
+            }
+
+            return result;
+        }
+    }
+
+    /// <summary>
+    /// Wraps an <see cref="ISaveDataExtraDataAccessor"/>, converting its returned <see cref="Result"/>s
+    /// to save-data-specific <see cref="Result"/>s.
+    /// </summary>
+    public class SaveDataExtraDataResultConvertAccessor : ISaveDataExtraDataAccessor
+    {
+        private ReferenceCountedDisposable<ISaveDataExtraDataAccessor> _accessor;
+
+        public SaveDataExtraDataResultConvertAccessor(
+            ref ReferenceCountedDisposable<ISaveDataExtraDataAccessor> accessor)
+        {
+            _accessor = Shared.Move(ref accessor);
+        }
+
+        public static ReferenceCountedDisposable<ISaveDataExtraDataAccessor> CreateShared(
+            ref ReferenceCountedDisposable<ISaveDataExtraDataAccessor> accessor)
+        {
+            var resultConvertAccessor = new SaveDataExtraDataResultConvertAccessor(ref accessor);
+            return new ReferenceCountedDisposable<ISaveDataExtraDataAccessor>(resultConvertAccessor);
+        }
+
+        public void Dispose()
+        {
+            _accessor?.Dispose();
+            _accessor = null;
+        }
+
+        public Result WriteExtraData(in SaveDataExtraData extraData)
+        {
+            Result rc = _accessor.Target.WriteExtraData(in extraData);
+            return SaveDataResultConvert.ConvertSaveFsDriverPublicResult(rc);
+        }
+
+        public Result CommitExtraData(bool updateTimeStamp)
+        {
+            Result rc = _accessor.Target.CommitExtraData(updateTimeStamp);
+            return SaveDataResultConvert.ConvertSaveFsDriverPublicResult(rc);
+        }
+
+        public Result ReadExtraData(out SaveDataExtraData extraData)
+        {
+            Result rc = _accessor.Target.ReadExtraData(out extraData);
+            return SaveDataResultConvert.ConvertSaveFsDriverPublicResult(rc);
+        }
+
+        public void RegisterCacheObserver(ISaveDataExtraDataAccessorCacheObserver observer, SaveDataSpaceId spaceId,
+            ulong saveDataId)
+        {
+            _accessor.Target.RegisterCacheObserver(observer, spaceId, saveDataId);
+        }
+    }
+}
\ No newline at end of file