When verify fails, dump the good/bad blocks to files

This makes it easy to compare afterwards to see what kind of
corruption was experienced.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/verify.h b/verify.h
index a6f8974..d5a906e 100644
--- a/verify.h
+++ b/verify.h
@@ -30,6 +30,7 @@
 	unsigned int fio_magic;
 	unsigned int len;
 	unsigned int verify_type;
+	unsigned long rand_seed;
 };
 
 struct vhdr_md5 {
@@ -71,7 +72,7 @@
 extern int __must_check get_next_verify(struct thread_data *td, struct io_u *);
 extern int __must_check verify_io_u(struct thread_data *, struct io_u *);
 extern int verify_io_u_async(struct thread_data *, struct io_u *);
-extern void fill_pattern(struct thread_data *td, void *p, unsigned int len, struct io_u *io_u);
+extern void fill_pattern(struct thread_data *td, void *p, unsigned int len, struct io_u *io_u, unsigned long seed, int use_seed);
 
 /*
  * Async verify offload