Index: linux-2.6/mm/filemap.c
===================================================================
--- linux-2.6.orig/mm/filemap.c
+++ linux-2.6/mm/filemap.c
@@ -2184,6 +2184,7 @@ fs_write_aop_error:
 	return written ? written : status;
 }
 
+#include <linux/kallsyms.h>
 static ssize_t generic_perform_write(struct file *file,
 				struct iov_iter *i, loff_t pos)
 {
@@ -2243,6 +2244,13 @@ again:
 						page, fsdata);
 		if (unlikely(status < 0))
 			break;
+		if (status > copied) {
+			print_symbol("%s returned more than it should!\n", (unsigned long)a_ops->write_end);
+			printk("status = %ld, copied = %lu\n", status, copied);
+			dump_stack();
+			status = copied; /* try to fix */
+		}
+
 		copied = status;
 
 		cond_resched();