From: Suparna Bhattacharya

wait_on_page_writeback_range shouldn't wait for pages beyond the
specified range. Ideally, the radix-tree-lookup could accept an
end_index parameter so that it doesn't return the extra pages
in the first place, but for now we just add a few extra checks

diff -upN reference/mm/filemap.c current/mm/filemap.c
--- reference/mm/filemap.c	2004-05-09 13:45:18.000000000 -0700
+++ current/mm/filemap.c	2004-05-09 13:45:20.000000000 -0700
@@ -189,7 +189,8 @@ static int wait_on_page_writeback_range(
 
 	pagevec_init(&pvec, 0);
 	index = start;
-	while ((nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+	while ((index <= end) && 
+			(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
 			PAGECACHE_TAG_WRITEBACK,
 			min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1))) {
 		unsigned i;
@@ -197,6 +198,10 @@ static int wait_on_page_writeback_range(
 		for (i = 0; i < nr_pages; i++) {
 			struct page *page = pvec.pages[i];
 
+			/* until radix tree lookup accepts end_index */
+			if (page->index > end) {
+				continue;
+			}
 			wait_on_page_writeback(page);
 			if (PageError(page))
 				ret = -EIO;