diff --git a/src/LibHac/Fs/Impl/FileServiceObjectAdapter.cs b/src/LibHac/Fs/Impl/FileServiceObjectAdapter.cs
index 9973e9a3..3781c2ae 100644
--- a/src/LibHac/Fs/Impl/FileServiceObjectAdapter.cs
+++ b/src/LibHac/Fs/Impl/FileServiceObjectAdapter.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Runtime.CompilerServices;
 using LibHac.Common;
+using LibHac.Sf;
 using IFile = LibHac.Fs.Fsa.IFile;
 using IFileSf = LibHac.FsSrv.Sf.IFile;
 
@@ -21,12 +22,12 @@ namespace LibHac.Fs.Impl
 
         protected override Result DoRead(out long bytesRead, long offset, Span<byte> destination, in ReadOption option)
         {
-            return BaseFile.Target.Read(out bytesRead, offset, destination, option);
+            return BaseFile.Target.Read(out bytesRead, offset, new OutBuffer(destination), destination.Length, option);
         }
 
         protected override Result DoWrite(long offset, ReadOnlySpan<byte> source, in WriteOption option)
         {
-            return BaseFile.Target.Write(offset, source, option);
+            return BaseFile.Target.Write(offset, new InBuffer(source), source.Length, option);
         }
 
         protected override Result DoFlush()
@@ -44,7 +45,8 @@ namespace LibHac.Fs.Impl
             return BaseFile.Target.GetSize(out size);
         }
 
-        protected override Result DoOperateRange(Span<byte> outBuffer, OperationId operationId, long offset, long size, ReadOnlySpan<byte> inBuffer)
+        protected override Result DoOperateRange(Span<byte> outBuffer, OperationId operationId, long offset, long size,
+            ReadOnlySpan<byte> inBuffer)
         {
             switch (operationId)
             {
@@ -72,4 +74,4 @@ namespace LibHac.Fs.Impl
             base.Dispose(disposing);
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/Fs/Impl/StorageServiceObjectAdapter.cs b/src/LibHac/Fs/Impl/StorageServiceObjectAdapter.cs
index d0d110ae..49cbb4f0 100644
--- a/src/LibHac/Fs/Impl/StorageServiceObjectAdapter.cs
+++ b/src/LibHac/Fs/Impl/StorageServiceObjectAdapter.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Runtime.CompilerServices;
 using LibHac.Common;
+using LibHac.Sf;
 using IStorageSf = LibHac.FsSrv.Sf.IStorage;
 
 namespace LibHac.Fs.Impl
@@ -31,12 +32,12 @@ namespace LibHac.Fs.Impl
 
         protected override Result DoRead(long offset, Span<byte> destination)
         {
-            return BaseStorage.Target.Read(offset, destination);
+            return BaseStorage.Target.Read(offset, new OutBuffer(destination), destination.Length);
         }
 
         protected override Result DoWrite(long offset, ReadOnlySpan<byte> source)
         {
-            return BaseStorage.Target.Write(offset, source);
+            return BaseStorage.Target.Write(offset, new InBuffer(source), source.Length);
         }
 
         protected override Result DoFlush()
@@ -54,7 +55,8 @@ namespace LibHac.Fs.Impl
             return BaseStorage.Target.GetSize(out size);
         }
 
-        protected override Result DoOperateRange(Span<byte> outBuffer, OperationId operationId, long offset, long size, ReadOnlySpan<byte> inBuffer)
+        protected override Result DoOperateRange(Span<byte> outBuffer, OperationId operationId, long offset, long size,
+            ReadOnlySpan<byte> inBuffer)
         {
             switch (operationId)
             {
@@ -82,4 +84,4 @@ namespace LibHac.Fs.Impl
             base.Dispose(disposing);
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/FsSrv/Impl/FileInterfaceAdapter.cs b/src/LibHac/FsSrv/Impl/FileInterfaceAdapter.cs
index 5394d0ec..1f70a85b 100644
--- a/src/LibHac/FsSrv/Impl/FileInterfaceAdapter.cs
+++ b/src/LibHac/FsSrv/Impl/FileInterfaceAdapter.cs
@@ -2,6 +2,7 @@
 using System.Runtime.CompilerServices;
 using LibHac.Common;
 using LibHac.Fs;
+using LibHac.Sf;
 using IFile = LibHac.Fs.Fsa.IFile;
 using IFileSf = LibHac.FsSrv.Sf.IFile;
 
@@ -20,7 +21,7 @@ namespace LibHac.FsSrv.Impl
             parentFileSystem = null;
         }
 
-        public Result Read(out long bytesRead, long offset, Span<byte> destination, ReadOption option)
+        public Result Read(out long bytesRead, long offset, OutBuffer destination, long size, ReadOption option)
         {
             const int maxTryCount = 2;
             UnsafeHelpers.SkipParamInit(out bytesRead);
@@ -28,7 +29,7 @@ namespace LibHac.FsSrv.Impl
             if (offset < 0)
                 return ResultFs.InvalidOffset.Log();
 
-            if (destination.Length < 0)
+            if (destination.Size < 0)
                 return ResultFs.InvalidSize.Log();
 
             Result rc = Result.Success;
@@ -36,7 +37,7 @@ namespace LibHac.FsSrv.Impl
 
             for (int tryNum = 0; tryNum < maxTryCount; tryNum++)
             {
-                rc = BaseFile.Read(out tmpBytesRead, offset, destination, option);
+                rc = BaseFile.Read(out tmpBytesRead, offset, destination.Buffer.Slice(0, (int)size), option);
 
                 // Retry on ResultDataCorrupted
                 if (!ResultFs.DataCorrupted.Includes(rc))
@@ -49,17 +50,17 @@ namespace LibHac.FsSrv.Impl
             return Result.Success;
         }
 
-        public Result Write(long offset, ReadOnlySpan<byte> source, WriteOption option)
+        public Result Write(long offset, InBuffer source, long size, WriteOption option)
         {
             if (offset < 0)
                 return ResultFs.InvalidOffset.Log();
 
-            if (source.Length < 0)
+            if (source.Size < 0)
                 return ResultFs.InvalidSize.Log();
 
-            // Note: Thread priority is temporarily when writing in FS
+            // Note: Thread priority is temporarily increased when writing in FS
 
-            return BaseFile.Write(offset, source, option);
+            return BaseFile.Write(offset, source.Buffer.Slice(0, (int)size), option);
         }
 
         public Result Flush()
@@ -113,8 +114,8 @@ namespace LibHac.FsSrv.Impl
             {
                 Unsafe.SkipInit(out QueryRangeInfo info);
 
-                Result rc = BaseFile.OperateRange(SpanHelpers.AsByteSpan(ref info), OperationId.QueryRange, offset, size,
-                    ReadOnlySpan<byte>.Empty);
+                Result rc = BaseFile.OperateRange(SpanHelpers.AsByteSpan(ref info), OperationId.QueryRange, offset,
+                    size, ReadOnlySpan<byte>.Empty);
                 if (rc.IsFailure()) return rc;
 
                 rangeInfo.Merge(in info);
@@ -129,4 +130,4 @@ namespace LibHac.FsSrv.Impl
             ParentFs?.Dispose();
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/FsSrv/Impl/StorageInterfaceAdapter.cs b/src/LibHac/FsSrv/Impl/StorageInterfaceAdapter.cs
index d59b50cd..1d178d65 100644
--- a/src/LibHac/FsSrv/Impl/StorageInterfaceAdapter.cs
+++ b/src/LibHac/FsSrv/Impl/StorageInterfaceAdapter.cs
@@ -2,6 +2,7 @@
 using System.Runtime.CompilerServices;
 using LibHac.Common;
 using LibHac.Fs;
+using LibHac.Sf;
 using IStorageSf = LibHac.FsSrv.Sf.IStorage;
 
 namespace LibHac.FsSrv.Impl
@@ -27,21 +28,21 @@ namespace LibHac.FsSrv.Impl
             BaseStorage?.Dispose();
         }
 
-        public Result Read(long offset, Span<byte> destination)
+        public Result Read(long offset, OutBuffer destination, long size)
         {
             const int maxTryCount = 2;
 
             if (offset < 0)
                 return ResultFs.InvalidOffset.Log();
 
-            if (destination.Length < 0)
+            if (destination.Size < 0)
                 return ResultFs.InvalidSize.Log();
 
             Result rc = Result.Success;
 
             for (int tryNum = 0; tryNum < maxTryCount; tryNum++)
             {
-                rc = BaseStorage.Target.Read(offset, destination);
+                rc = BaseStorage.Target.Read(offset, destination.Buffer.Slice(0, (int)size));
 
                 // Retry on ResultDataCorrupted
                 if (!ResultFs.DataCorrupted.Includes(rc))
@@ -51,17 +52,17 @@ namespace LibHac.FsSrv.Impl
             return rc;
         }
 
-        public Result Write(long offset, ReadOnlySpan<byte> source)
+        public Result Write(long offset, InBuffer source, long size)
         {
             if (offset < 0)
                 return ResultFs.InvalidOffset.Log();
 
-            if (source.Length < 0)
+            if (source.Size < 0)
                 return ResultFs.InvalidSize.Log();
 
             // Note: Thread priority is temporarily increased when writing in FS
 
-            return BaseStorage.Target.Write(offset, source);
+            return BaseStorage.Target.Write(offset, source.Buffer.Slice(0, (int)size));
         }
 
         public Result Flush()
@@ -107,4 +108,4 @@ namespace LibHac.FsSrv.Impl
             return Result.Success;
         }
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/FsSrv/Sf/IFile.cs b/src/LibHac/FsSrv/Sf/IFile.cs
index 3e35af92..5236bf59 100644
--- a/src/LibHac/FsSrv/Sf/IFile.cs
+++ b/src/LibHac/FsSrv/Sf/IFile.cs
@@ -1,15 +1,16 @@
 using System;
 using LibHac.Fs;
+using LibHac.Sf;
 
 namespace LibHac.FsSrv.Sf
 {
     public interface IFile : IDisposable
     {
-        Result Read(out long bytesRead, long offset, Span<byte> destination, ReadOption option);
-        Result Write(long offset, ReadOnlySpan<byte> source, WriteOption option);
+        Result Read(out long bytesRead, long offset, OutBuffer destination, long size, ReadOption option);
+        Result Write(long offset, InBuffer source, long size, WriteOption option);
         Result Flush();
         Result SetSize(long size);
         Result GetSize(out long size);
         Result OperateRange(out QueryRangeInfo rangeInfo, int operationId, long offset, long size);
     }
-}
+}
\ No newline at end of file
diff --git a/src/LibHac/FsSrv/Sf/IStorage.cs b/src/LibHac/FsSrv/Sf/IStorage.cs
index 264dbd49..5074556d 100644
--- a/src/LibHac/FsSrv/Sf/IStorage.cs
+++ b/src/LibHac/FsSrv/Sf/IStorage.cs
@@ -1,15 +1,16 @@
 using System;
 using LibHac.Fs;
+using LibHac.Sf;
 
 namespace LibHac.FsSrv.Sf
 {
     public interface IStorage : IDisposable
     {
-        Result Read(long offset, Span<byte> destination);
-        Result Write(long offset, ReadOnlySpan<byte> source);
+        Result Read(long offset, OutBuffer destination, long size);
+        Result Write(long offset, InBuffer source, long size);
         Result Flush();
         Result SetSize(long size);
         Result GetSize(out long size);
         Result OperateRange(out QueryRangeInfo rangeInfo, int operationId, long offset, long size);
     }
-}
+}
\ No newline at end of file