diff --git a/src/modules/filesystem/physfs/Filesystem.cpp b/src/modules/filesystem/physfs/Filesystem.cpp
index 2242af76c..3274a68ed 100644
--- a/src/modules/filesystem/physfs/Filesystem.cpp
+++ b/src/modules/filesystem/physfs/Filesystem.cpp
@@ -174,12 +174,12 @@ bool Filesystem::setupWriteDirectory()
 	return true;
 }
 
-File *Filesystem::newFile(const char *filename)
+File *Filesystem::newFile(const char *filename) const
 {
 	return new File(filename);
 }
 
-FileData *Filesystem::newFileData(void *data, unsigned int size, const char *filename)
+FileData *Filesystem::newFileData(void *data, unsigned int size, const char *filename) const
 {
 	FileData *fd = new FileData(size, std::string(filename));
 
@@ -189,7 +189,7 @@ FileData *Filesystem::newFileData(void *data, unsigned int size, const char *fil
 	return fd;
 }
 
-FileData *Filesystem::newFileData(const char *b64, const char *filename)
+FileData *Filesystem::newFileData(const char *b64, const char *filename) const
 {
 	int size = strlen(b64);
 	int outsize = 0;
@@ -270,21 +270,21 @@ const char *Filesystem::getSaveDirectory()
 	return save_path_full.c_str();
 }
 
-bool Filesystem::exists(const char *file)
+bool Filesystem::exists(const char *file) const
 {
 	if (PHYSFS_exists(file))
 		return true;
 	return false;
 }
 
-bool Filesystem::isDirectory(const char *file)
+bool Filesystem::isDirectory(const char *file) const
 {
 	if (PHYSFS_isDirectory(file))
 		return true;
 	return false;
 }
 
-bool Filesystem::isFile(const char *file)
+bool Filesystem::isFile(const char *file) const
 {
 	return exists(file) && !isDirectory(file);
 }
@@ -523,7 +523,7 @@ int Filesystem::getLastModified(lua_State *L)
 	return 1;
 }
 
-int64 Filesystem::getSize(const char *filename)
+int64 Filesystem::getSize(const char *filename) const
 {
 	File file(filename);
 	int64 size = file.getSize();
diff --git a/src/modules/filesystem/physfs/Filesystem.h b/src/modules/filesystem/physfs/Filesystem.h
index 9a23695d0..8865aa960 100644
--- a/src/modules/filesystem/physfs/Filesystem.h
+++ b/src/modules/filesystem/physfs/Filesystem.h
@@ -147,7 +147,7 @@ public:
 	/**
 	 * Creates a new file.
 	 **/
-	File *newFile(const char *filename);
+	File *newFile(const char *filename) const;
 
 	/**
 	 * Creates a new FileData object. Data will be copied.
@@ -155,13 +155,13 @@ public:
 	 * @param size The size of the data.
 	 * @param filename The full filename used to file type identification.
 	 **/
-	FileData *newFileData(void *data, unsigned int size, const char *filename);
+	FileData *newFileData(void *data, unsigned int size, const char *filename) const;
 
 	/**
 	 * Creates a new FileData object from base64 data.
 	 * @param b64 The base64 data.
 	 **/
-	FileData *newFileData(const char *b64, const char *filename);
+	FileData *newFileData(const char *b64, const char *filename) const;
 
 	/**
 	 * Gets the current working directory.
@@ -190,20 +190,20 @@ public:
 	 * or not.
 	 * @param file The filename to check.
 	 **/
-	bool exists(const char *file);
+	bool exists(const char *file) const;
 
 	/**
 	 * Checks if an existing file really is a directory.
 	 * @param file The filename to check.
 	 **/
-	bool isDirectory(const char *file);
+	bool isDirectory(const char *file) const;
 
 	/**
 	 * Checks if an existing file really is a file,
 	 * and not a directory.
 	 * @param file The filename to check.
 	 **/
-	bool isFile(const char *file);
+	bool isFile(const char *file) const;
 
 	/**
 	 * Creates a directory. Write dir must be set.
@@ -292,7 +292,7 @@ public:
 	 * Gets the size of a file in bytes.
 	 * @param filename The name of the file.
 	 **/
-	int64 getSize(const char *filename);
+	int64 getSize(const char *filename) const;
 
 	/**
 	 * Text file line-reading iterator function used and