--- linux-2.6.0-test10-mm1.ddm/mm/filemap.c	2003-12-05 17:14:57.000000000 -0800
+++ linux-2.6.0-test10-mm1.ddm.DIO/mm/filemap.c	2003-12-16 17:03:02.801786218 -0800
@@ -188,6 +188,20 @@ restart:
 		struct page *page;
 
 		page = list_entry(mapping->locked_pages.next,struct page,list);
+		/*
+		 * If the page is locked, it might be in process of being 
+		 * setup for writeback but without PG_writeback set 
+		 * and with PG_dirty cleared.
+		 * (PG_dirty is cleared BEFORE PG_writeback is set)
+		 * So, wait for the PG_locked to clear, then start over.
+		 */
+		if (PageLocked(page)) {
+			page_cache_get(page);
+			spin_unlock(&mapping->page_lock);
+			wait_on_page_locked(page);
+			page_cache_release(page);
+			goto restart;
+		}
 		list_del(&page->list);
 		if (PageDirty(page))
 			list_add(&page->list, &mapping->dirty_pages);