5 files changed, 24 insertions, 16 deletions
diff --git a/src/core/file_sys/disk_archive.cpp b/src/core/file_sys/disk_archive.cpp
index 0c55a4863..2dca895fd 100644
--- a/src/core/file_sys/disk_archive.cpp
+++ b/src/core/file_sys/disk_archive.cpp
@@ -124,17 +124,23 @@ bool DiskFile::Open() {
     return file->IsOpen();
 }
 
-size_t DiskFile::Read(const u64 offset, const size_t length, u8* buffer) const {
+ResultVal<size_t> DiskFile::Read(const u64 offset, const size_t length, u8* buffer) const {
+    if (!mode.read_flag && !mode.write_flag)
+        return ResultCode(ErrorDescription::FS_InvalidOpenFlags, ErrorModule::FS, ErrorSummary::Canceled, ErrorLevel::Status);
+
     file->Seek(offset, SEEK_SET);
-    return file->ReadBytes(buffer, length);
+    return MakeResult<size_t>(file->ReadBytes(buffer, length));
 }
 
-size_t DiskFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
+ResultVal<size_t> DiskFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
+    if (!mode.write_flag)
+        return ResultCode(ErrorDescription::FS_InvalidOpenFlags, ErrorModule::FS, ErrorSummary::Canceled, ErrorLevel::Status);
+
     file->Seek(offset, SEEK_SET);
     size_t written = file->WriteBytes(buffer, length);
     if (flush)
         file->Flush();
-    return written;
+    return MakeResult<size_t>(written);
 }
 
 u64 DiskFile::GetSize() const {
diff --git a/src/core/file_sys/disk_archive.h b/src/core/file_sys/disk_archive.h
index c0a3d3f7b..96d86ad21 100644
--- a/src/core/file_sys/disk_archive.h
+++ b/src/core/file_sys/disk_archive.h
@@ -55,8 +55,8 @@ public:
     DiskFile(const DiskArchive& archive, const Path& path, const Mode mode);
 
     bool Open() override;
-    size_t Read(u64 offset, size_t length, u8* buffer) const override;
-    size_t Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
+    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
+    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
     u64 GetSize() const override;
     bool SetSize(u64 size) const override;
     bool Close() const override;
diff --git a/src/core/file_sys/file_backend.h b/src/core/file_sys/file_backend.h
index df7165df3..21864a73c 100644
--- a/src/core/file_sys/file_backend.h
+++ b/src/core/file_sys/file_backend.h
@@ -7,6 +7,7 @@
 #include <cstddef>
 
 #include "common/common_types.h"
+#include "core/hle/result.h"
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // FileSys namespace
@@ -29,9 +30,9 @@ public:
      * @param offset Offset in bytes to start reading data from
      * @param length Length in bytes of data to read from file
      * @param buffer Buffer to read data into
-     * @return Number of bytes read
+     * @return Number of bytes read, or error code
      */
-    virtual size_t Read(u64 offset, size_t length, u8* buffer) const = 0;
+    virtual ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const = 0;
 
     /**
      * Write data to the file
@@ -39,9 +40,9 @@ public:
      * @param length Length in bytes of data to write to file
      * @param flush The flush parameters (0 == do not flush)
      * @param buffer Buffer to read data from
-     * @return Number of bytes written
+     * @return Number of bytes written, or error code
      */
-    virtual size_t Write(u64 offset, size_t length, bool flush, const u8* buffer) const = 0;
+    virtual ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const = 0;
 
     /**
      * Get the size of the file in bytes
diff --git a/src/core/file_sys/ivfc_archive.cpp b/src/core/file_sys/ivfc_archive.cpp
index f2f96ef1a..e7b37e09d 100644
--- a/src/core/file_sys/ivfc_archive.cpp
+++ b/src/core/file_sys/ivfc_archive.cpp
@@ -68,17 +68,18 @@ u64 IVFCArchive::GetFreeBytes() const {
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
-size_t IVFCFile::Read(const u64 offset, const size_t length, u8* buffer) const {
+ResultVal<size_t> IVFCFile::Read(const u64 offset, const size_t length, u8* buffer) const {
     LOG_TRACE(Service_FS, "called offset=%llu, length=%zu", offset, length);
     romfs_file->Seek(data_offset + offset, SEEK_SET);
     size_t read_length = (size_t)std::min((u64)length, data_size - offset);
 
-    return romfs_file->ReadBytes(buffer, read_length);
+    return MakeResult<size_t>(romfs_file->ReadBytes(buffer, read_length));
 }
 
-size_t IVFCFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
+ResultVal<size_t> IVFCFile::Write(const u64 offset, const size_t length, const bool flush, const u8* buffer) const {
     LOG_ERROR(Service_FS, "Attempted to write to IVFC file");
-    return 0;
+    // TODO(Subv): Find error code
+    return MakeResult<size_t>(0);
 }
 
 u64 IVFCFile::GetSize() const {
diff --git a/src/core/file_sys/ivfc_archive.h b/src/core/file_sys/ivfc_archive.h
index 5d3a5b61e..acc7e60f5 100644
--- a/src/core/file_sys/ivfc_archive.h
+++ b/src/core/file_sys/ivfc_archive.h
@@ -56,8 +56,8 @@ public:
         : romfs_file(file), data_offset(offset), data_size(size) {}
 
     bool Open() override { return true; }
-    size_t Read(u64 offset, size_t length, u8* buffer) const override;
-    size_t Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
+    ResultVal<size_t> Read(u64 offset, size_t length, u8* buffer) const override;
+    ResultVal<size_t> Write(u64 offset, size_t length, bool flush, const u8* buffer) const override;
     u64 GetSize() const override;
     bool SetSize(u64 size) const override;
     bool Close() const override { return false; }