diff -Nru linux-2.4.20/mm/memory.c.orig linux-2.4.20/mm/memory.c
--- linux-2.4.20/mm/memory.c.orig	2003-04-01 16:33:48.000000000 -0800
+++ linux-2.4.20/mm/memory.c	2003-04-01 16:41:34.000000000 -0800
@@ -553,6 +553,7 @@
 	if (err)
 		return err;
 
+	iobuf->rw = rw;
 	iobuf->locked = 0;
 	iobuf->offset = va & (PAGE_SIZE-1);
 	iobuf->length = len;
@@ -569,11 +570,10 @@
 		return err;
 	}
 	iobuf->nr_pages = err;
-	while (pgcount--) {
-		/* FIXME: flush superflous for rw==READ,
-		 * probably wrong function for rw==WRITE
-		 */
-		flush_dcache_page(iobuf->maplist[pgcount]);
+	/* if rw==WRITE, get updated data before writing them to disk */
+	if (rw==WRITE) {
+		while (pgcount--) 
+			flush_dcache_page(iobuf->maplist[pgcount]);
 	}
 	dprintk ("map_user_kiobuf: end OK\n");
 	return 0;
@@ -628,9 +628,10 @@
 		if (map) {
 			if (iobuf->locked)
 				UnlockPage(map);
-			/* FIXME: cache flush missing for rw==READ
-			 * FIXME: call the correct reference counting function
-			 */
+			/* if rw==READ, flush dcache before user uses data */
+			if (iobuf->rw==READ) {
+				flush_dcache_page(iobuf->maplist[i]);
+			}
 			page_cache_release(map);
 		}
 	}
diff -Nru linux-2.4.20/include/linux/iobuf.h.orig linux-2.4.20/include/linux/iobuf.h
--- linux-2.4.20/include/linux/iobuf.h.orig	2002-11-28 15:53:15.000000000 -0800
+++ linux-2.4.20/include/linux/iobuf.h	2003-04-01 16:34:16.000000000 -0800
@@ -32,6 +32,7 @@
 
 struct kiobuf 
 {
+	int		rw;		/* mapped for READ or WRITE */
 	int		nr_pages;	/* Pages actually referenced */
 	int		array_len;	/* Space in the allocated lists */
 	int		offset;		/* Offset to start of valid data */