--- a/libgfortran/io/file_pos.c	Fri Oct 27 22:46:09 2017 +0900
+++ b/libgfortran/io/file_pos.c	Thu Oct 25 07:37:49 2018 +0900
@@ -1,4 +1,4 @@
-/* Copyright (C) 2002-2017 Free Software Foundation, Inc.
+/* Copyright (C) 2002-2018 Free Software Foundation, Inc.
    Contributed by Andy Vaught and Janne Blomqvist
 
 This file is part of the GNU Fortran runtime library (libgfortran).
@@ -25,6 +25,7 @@
 #include "io.h"
 #include "fbuf.h"
 #include "unix.h"
+#include "async.h"
 #include <string.h>
 
 /* file_pos.c-- Implement the file positioning statements, i.e. BACKSPACE,
@@ -187,6 +188,7 @@
 st_backspace (st_parameter_filepos *fpp)
 {
   gfc_unit *u;
+  bool needs_unlock = false;
 
   library_start (&fpp->common);
 
@@ -214,6 +216,17 @@
       goto done;
     }
 
+  if (ASYNC_IO && u->au)
+    {
+      if (async_wait (&(fpp->common), u->au))
+	return;
+      else
+	{
+	  needs_unlock = true;
+	  LOCK (&u->au->io_lock);
+	}
+    }
+
   /* Make sure format buffer is flushed and reset.  */
   if (u->flags.form == FORM_FORMATTED)
     {
@@ -267,7 +280,12 @@
 
  done:
   if (u != NULL)
-    unlock_unit (u);
+    {
+      unlock_unit (u);
+
+      if (ASYNC_IO && u->au && needs_unlock)
+	UNLOCK (&u->au->io_lock);
+    }
 
   library_end ();
 }
@@ -280,6 +298,7 @@
 st_endfile (st_parameter_filepos *fpp)
 {
   gfc_unit *u;
+  bool needs_unlock = false;
 
   library_start (&fpp->common);
 
@@ -294,6 +313,17 @@
 	  goto done;
 	}
 
+      if (ASYNC_IO && u->au)
+	{
+	  if (async_wait (&(fpp->common), u->au))
+	    return;
+	  else
+	    {
+	      needs_unlock = true;
+	      LOCK (&u->au->io_lock);
+	    }
+	}
+
       if (u->flags.access == ACCESS_SEQUENTIAL
       	  && u->endfile == AFTER_ENDFILE)
 	{
@@ -376,8 +406,11 @@
 	}
     }
 
-  done:
-    unlock_unit (u);
+ done:
+  if (ASYNC_IO && u->au && needs_unlock)
+    UNLOCK (&u->au->io_lock);
+
+  unlock_unit (u);
 
   library_end ();
 }
@@ -390,6 +423,7 @@
 st_rewind (st_parameter_filepos *fpp)
 {
   gfc_unit *u;
+  bool needs_unlock = true;
 
   library_start (&fpp->common);
 
@@ -401,6 +435,17 @@
 			"Cannot REWIND a file opened for DIRECT access");
       else
 	{
+	  if (ASYNC_IO && u->au)
+	    {
+	      if (async_wait (&(fpp->common), u->au))
+		return;
+	      else
+		{
+		  needs_unlock = true;
+		  LOCK (&u->au->io_lock);
+		}
+	    }
+
 	  /* If there are previously written bytes from a write with ADVANCE="no",
 	     add a record marker before performing the ENDFILE.  */
 
@@ -436,6 +481,10 @@
 	}
       /* Update position for INQUIRE.  */
       u->flags.position = POSITION_REWIND;
+
+      if (ASYNC_IO && u->au && needs_unlock)
+	UNLOCK (&u->au->io_lock);
+
       unlock_unit (u);
     }
 
@@ -450,12 +499,24 @@
 st_flush (st_parameter_filepos *fpp)
 {
   gfc_unit *u;
+  bool needs_unlock = false;
 
   library_start (&fpp->common);
 
   u = find_unit (fpp->common.unit);
   if (u != NULL)
     {
+      if (ASYNC_IO && u->au)
+	{
+	  if (async_wait (&(fpp->common), u->au))
+	    return;
+	  else
+	    {
+	      needs_unlock = true;
+	      LOCK (&u->au->io_lock);
+	    }
+	}
+
       /* Make sure format buffer is flushed.  */
       if (u->flags.form == FORM_FORMATTED)
         fbuf_flush (u, u->mode);
@@ -469,5 +530,8 @@
     generate_error (&fpp->common, LIBERROR_BAD_OPTION,
 			"Specified UNIT in FLUSH is not connected");
 
+  if (needs_unlock)
+    UNLOCK (&u->au->io_lock);
+
   library_end ();
 }