diff --git a/include/server.h b/include/server.h
index 858131c5c4a..1e437041549 100644
--- a/include/server.h
+++ b/include/server.h
@@ -27,7 +27,7 @@
 struct request_header
 {
     IN  int            req;          /* request code */
-    IN  unsigned short fixed_size;   /* size of the fixed part of the request */
+    IN  unsigned short var_offset;   /* offset of the variable part of the request */
     IN  unsigned short var_size;     /* size of the variable part of the request */
     OUT unsigned int   error;        /* error result */
 };
@@ -864,7 +864,6 @@ struct get_mapping_info_request
     OUT void*        base;          /* default base addr (for VPROT_IMAGE mapping) */
     OUT handle_t     shared_file;   /* shared mapping file handle */
     OUT int          shared_size;   /* shared mapping size */
-    OUT int          anonymous;     /* anonymous mapping? */
 };
 
 
@@ -1594,7 +1593,7 @@ union generic_request
     struct async_result_request async_result;
 };
 
-#define SERVER_PROTOCOL_VERSION 37
+#define SERVER_PROTOCOL_VERSION 38
 
 /* ### make_requests end ### */
 /* Everything above this line is generated automatically by tools/make_requests */
@@ -1622,6 +1621,7 @@ struct server_buffer_info
 extern unsigned int wine_server_call( enum request req );
 extern unsigned int server_call_fd( enum request req, int fd_out );
 extern void server_protocol_error( const char *err, ... ) WINE_NORETURN;
+extern void server_protocol_perror( const char *err ) WINE_NORETURN;
 extern void *wine_server_alloc_req( size_t fixed_size, size_t var_size );
 extern int wine_server_recv_fd( int handle, int cache );
 extern const char *get_config_dir(void);
diff --git a/memory/virtual.c b/memory/virtual.c
index 536585b17ef..03392640e8c 100644
--- a/memory/virtual.c
+++ b/memory/virtual.c
@@ -1494,7 +1494,7 @@ LPVOID WINAPI MapViewOfFileEx(
     UINT ptr = (UINT)-1, size = 0;
     int flags = MAP_PRIVATE;
     int unix_handle = -1;
-    int prot, anonymous, res;
+    int prot, res;
     void *base;
     DWORD size_low, size_high, header_size, shared_size;
     HANDLE shared_file;
@@ -1520,15 +1520,11 @@ LPVOID WINAPI MapViewOfFileEx(
         header_size = req->header_size;
         shared_file = req->shared_file;
         shared_size = req->shared_size;
-        anonymous   = req->anonymous;
     }
     SERVER_END_REQ;
     if (res) goto error;
 
-    if (!anonymous)
-    {
-        if ((unix_handle = FILE_GetUnixHandle( handle, 0 )) == -1) goto error;
-    }
+    if ((unix_handle = FILE_GetUnixHandle( handle, 0 )) == -1) goto error;
 
     if (prot & VPROT_IMAGE)
         return map_image( handle, unix_handle, base, size_low, header_size,
diff --git a/scheduler/client.c b/scheduler/client.c
index ce9171faed8..1c022986d6e 100644
--- a/scheduler/client.c
+++ b/scheduler/client.c
@@ -102,9 +102,9 @@ void server_protocol_error( const char *err, ... )
 
 
 /***********************************************************************
- *           server_perror
+ *           server_protocol_perror
  */
-static void server_perror( const char *err )
+void server_protocol_perror( const char *err )
 {
     fprintf( stderr, "Client protocol error:%p: ", NtCurrentTeb()->tid );
     perror( err );
@@ -141,7 +141,7 @@ void *wine_server_alloc_req( size_t fixed_size, size_t var_size )
         server_protocol_error( "buffer overflow %d bytes\n",
                                (char *)req + size - (char *)NtCurrentTeb()->buffer_info );
     NtCurrentTeb()->buffer_info->cur_pos = pos + size;
-    req->header.fixed_size = fixed_size;
+    req->header.var_offset = pos + sizeof(*req);
     req->header.var_size = var_size;
     return req;
 }
@@ -152,15 +152,15 @@ void *wine_server_alloc_req( size_t fixed_size, size_t var_size )
  *
  * Send a request to the server.
  */
-static void send_request( enum request req, struct request_header *header )
+static void send_request( enum request req, union generic_request *request )
 {
-    header->req = req;
-    NtCurrentTeb()->buffer_info->cur_req = (char *)header - (char *)NtCurrentTeb()->buffer;
+    request->header.req = req;
+    NtCurrentTeb()->buffer_info->cur_req = (char *)request - (char *)NtCurrentTeb()->buffer;
     /* write a single byte; the value is ignored anyway */
-    if (write( NtCurrentTeb()->request_fd, header, 1 ) == -1)
+    if (write( NtCurrentTeb()->request_fd, request, 1 ) == -1)
     {
         if (errno == EPIPE) SYSDEPS_ExitThread(0);
-        server_perror( "sendmsg" );
+        server_protocol_perror( "sendmsg" );
     }
 }
 
@@ -169,7 +169,7 @@ static void send_request( enum request req, struct request_header *header )
  *
  * Send a request to the server, passing a file descriptor.
  */
-static void send_request_fd( enum request req, struct request_header *header, int fd )
+static void send_request_fd( enum request req, union generic_request *request, int fd )
 {
 #ifndef HAVE_MSGHDR_ACCRIGHTS
     struct cmsg_fd cmsg;
@@ -178,7 +178,7 @@ static void send_request_fd( enum request req, struct request_header *header, in
     struct iovec vec;
 
     /* write a single byte; the value is ignored anyway */
-    vec.iov_base = (void *)header;
+    vec.iov_base = (void *)request;
     vec.iov_len  = 1;
 
     msghdr.msg_name    = NULL;
@@ -199,12 +199,12 @@ static void send_request_fd( enum request req, struct request_header *header, in
     msghdr.msg_flags      = 0;
 #endif  /* HAVE_MSGHDR_ACCRIGHTS */
 
-    header->req = req;
+    request->header.req = req;
 
     if (sendmsg( NtCurrentTeb()->socket, &msghdr, 0 ) == -1)
     {
         if (errno == EPIPE) SYSDEPS_ExitThread(0);
-        server_perror( "sendmsg" );
+        server_protocol_perror( "sendmsg" );
     }
 }
 
@@ -224,7 +224,7 @@ static void wait_reply(void)
         if (!ret) break;
         if (errno == EINTR) continue;
         if (errno == EPIPE) break;
-        server_perror("read");
+        server_protocol_perror("read");
     }
     /* the server closed the connection; time to die... */
     SYSDEPS_ExitThread(0);
@@ -238,10 +238,10 @@ static void wait_reply(void)
  */
 unsigned int wine_server_call( enum request req )
 {
-    void *req_ptr = NtCurrentTeb()->buffer;
+    union generic_request *req_ptr = NtCurrentTeb()->buffer;
     send_request( req, req_ptr );
     wait_reply();
-    return ((struct request_header *)req_ptr)->error;
+    return req_ptr->header.error;
 }
 
 
@@ -253,13 +253,12 @@ unsigned int wine_server_call( enum request req )
 unsigned int server_call_fd( enum request req, int fd_out )
 {
     unsigned int res;
-    void *req_ptr = NtCurrentTeb()->buffer;
+    union generic_request *req_ptr = NtCurrentTeb()->buffer;
 
     send_request_fd( req, req_ptr, fd_out );
     wait_reply();
 
-    if ((res = ((struct request_header *)req_ptr)->error))
-        SetLastError( RtlNtStatusToDosError(res) );
+    if ((res = req_ptr->header.error)) SetLastError( RtlNtStatusToDosError(res) );
     return res;  /* error code */
 }
 
@@ -356,7 +355,7 @@ int wine_server_recv_fd( int handle, int cache )
         if (!ret) break;
         if (errno == EINTR) continue;
         if (errno == EPIPE) break;
-        server_perror("recvmsg");
+        server_protocol_perror("recvmsg");
     }
     /* the server closed the connection; time to die... */
     SYSDEPS_ExitThread(0);
@@ -613,10 +612,10 @@ int CLIENT_InitThread(void)
     fd = wine_server_recv_fd( 0, 0 );
     if (fd == -1) server_protocol_error( "no fd received for thread buffer\n" );
 
-    if ((size = lseek( fd, 0, SEEK_END )) == -1) server_perror( "lseek" );
+    if ((size = lseek( fd, 0, SEEK_END )) == -1) server_protocol_perror( "lseek" );
     teb->buffer = mmap( 0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0 );
     close( fd );
-    if (teb->buffer == (void*)-1) server_perror( "mmap" );
+    if (teb->buffer == (void*)-1) server_protocol_perror( "mmap" );
     teb->buffer_info = (struct server_buffer_info *)((char *)teb->buffer + size) - 1;
 
     wait_reply();
diff --git a/server/mapping.c b/server/mapping.c
index 8cd24b55298..2bfdd771643 100644
--- a/server/mapping.c
+++ b/server/mapping.c
@@ -338,7 +338,6 @@ DECL_HANDLER(get_mapping_info)
         req->base        = mapping->base;
         req->shared_file = 0;
         req->shared_size = mapping->shared_size;
-        req->anonymous   = !mapping->file;
         if (mapping->shared_file)
             req->shared_file = alloc_handle( current->process, mapping->shared_file,
                                              GENERIC_READ|GENERIC_WRITE, 0 );
diff --git a/server/request.h b/server/request.h
index 6eeadea19d8..9b8547db08d 100644
--- a/server/request.h
+++ b/server/request.h
@@ -52,7 +52,7 @@ static inline void *get_req_ptr( struct thread *thread )
 /* get the request vararg data */
 inline static void *get_req_data( const void *req )
 {
-    return ((union generic_request *)req + 1);
+    return (char *)current->buffer + ((struct request_header *)req)->var_offset;
 }
 
 /* get the request vararg size */
diff --git a/server/trace.c b/server/trace.c
index c47b4bad8fc..f8bafa64887 100644
--- a/server/trace.c
+++ b/server/trace.c
@@ -985,8 +985,7 @@ static void dump_get_mapping_info_reply( const struct get_mapping_info_request *
     fprintf( stderr, " header_size=%d,", req->header_size );
     fprintf( stderr, " base=%p,", req->base );
     fprintf( stderr, " shared_file=%d,", req->shared_file );
-    fprintf( stderr, " shared_size=%d,", req->shared_size );
-    fprintf( stderr, " anonymous=%d", req->anonymous );
+    fprintf( stderr, " shared_size=%d", req->shared_size );
 }
 
 static void dump_create_device_request( const struct create_device_request *req )