diff --git a/filesystem/filesystem.c b/filesystem/filesystem.c
index 7cf519c3..db02770b 100644
--- a/filesystem/filesystem.c
+++ b/filesystem/filesystem.c
@@ -2834,7 +2834,7 @@ FS_Tell
 Give the current position in a file
 ====================
 */
-fs_offset_t FS_Tell( file_t *file )
+fs_offset_t FS_Tell( const file_t *file )
 {
 	if( !file ) return 0;
 	return file->position - file->buff_len + file->buff_ind;
@@ -2847,7 +2847,7 @@ FS_Eof
 indicates at reached end of file
 ====================
 */
-qboolean FS_Eof( file_t *file )
+qboolean FS_Eof( const file_t *file )
 {
 	if( !file ) return true;
 	return (( file->position - file->buff_len + file->buff_ind ) == file->real_length ) ? true : false;
@@ -3161,7 +3161,7 @@ FS_FileLength
 return size of file in bytes
 ==================
 */
-fs_offset_t FS_FileLength( file_t *f )
+fs_offset_t FS_FileLength( const file_t *f )
 {
 	if( !f ) return 0;
 	return f->real_length;
diff --git a/filesystem/filesystem.h b/filesystem/filesystem.h
index 966d69f7..ff1b91ff 100644
--- a/filesystem/filesystem.h
+++ b/filesystem/filesystem.h
@@ -174,8 +174,8 @@ typedef struct fs_api_t
 	fs_offset_t (*Write)( file_t *file, const void *data, size_t datasize );
 	fs_offset_t (*Read)( file_t *file, void *buffer, size_t buffersize );
 	int (*Seek)( file_t *file, fs_offset_t offset, int whence );
-	fs_offset_t (*Tell)( file_t *file );
-	qboolean (*Eof)( file_t *file );
+	fs_offset_t (*Tell)( const file_t *file );
+	qboolean (*Eof)( const file_t *file );
 	int (*Flush)( file_t *file );
 	int (*Close)( file_t *file );
 	int (*Gets)( file_t *file, char *string, size_t bufsize );
@@ -184,7 +184,7 @@ typedef struct fs_api_t
 	int (*VPrintf)( file_t *file, const char *format, va_list ap );
 	int (*Printf)( file_t *file, const char *format, ... ) FORMAT_CHECK( 2 );
 	int (*Print)( file_t *file, const char *msg );
-	fs_offset_t (*FileLength)( file_t *f );
+	fs_offset_t (*FileLength)( const file_t *f );
 	qboolean (*FileCopy)( file_t *pOutput, file_t *pInput, int fileSize );
 
 	// file buffer ops
diff --git a/filesystem/filesystem_internal.h b/filesystem/filesystem_internal.h
index 39023dfe..fec87003 100644
--- a/filesystem/filesystem_internal.h
+++ b/filesystem/filesystem_internal.h
@@ -173,8 +173,8 @@ file_t *FS_Open( const char *filepath, const char *mode, qboolean gamedironly )
 fs_offset_t FS_Write( file_t *file, const void *data, size_t datasize );
 fs_offset_t FS_Read( file_t *file, void *buffer, size_t buffersize );
 int FS_Seek( file_t *file, fs_offset_t offset, int whence );
-fs_offset_t FS_Tell( file_t *file );
-qboolean FS_Eof( file_t *file );
+fs_offset_t FS_Tell( const file_t *file );
+qboolean FS_Eof( const file_t *file );
 int FS_Flush( file_t *file );
 int FS_Gets( file_t *file, char *string, size_t bufsize );
 int FS_UnGetc( file_t *file, char c );
@@ -182,7 +182,7 @@ int FS_Getc( file_t *file );
 int FS_VPrintf( file_t *file, const char *format, va_list ap );
 int FS_Printf( file_t *file, const char *format, ... ) FORMAT_CHECK( 2 );
 int FS_Print( file_t *file, const char *msg );
-fs_offset_t FS_FileLength( file_t *f );
+fs_offset_t FS_FileLength( const file_t *f );
 qboolean FS_FileCopy( file_t *pOutput, file_t *pInput, int fileSize );
 
 // file buffer ops