--- linux-2.6.9-rc4-mm1/mm/filemap.c.orig	2004-10-15 10:33:24.986209880 -0400
+++ linux-2.6.9-rc4-mm1/mm/filemap.c	2004-10-15 11:38:50.869384920 -0400
@@ -692,7 +692,7 @@ void do_generic_mapping_read(struct addr
 	unsigned long index, end_index, offset;
 	loff_t isize;
 	struct page *cached_page;
-	int error;
+	int error, nonblock = filp->f_flags & O_NONBLOCK;
 	struct file_ra_state ra = *_ra;
 
 	cached_page = NULL;
@@ -721,16 +721,27 @@ void do_generic_mapping_read(struct addr
 		nr = nr - offset;
 
 		cond_resched();
-		page_cache_readahead(mapping, &ra, filp, index);
+		if (!nonblock)
+			page_cache_readahead(mapping, &ra, filp, index);
 
 find_page:
 		page = find_get_page(mapping, index);
 		if (unlikely(page == NULL)) {
+			if (nonblock) {
+				desc->error = -EWOULDBLOCK;
+				break;
+			}
 			handle_ra_miss(mapping, &ra, index);
 			goto no_cached_page;
 		}
-		if (!PageUptodate(page))
+		if (!PageUptodate(page)) {
+			if (nonblock) {
+				page_cache_release(page);
+				desc->error = -EWOULDBLOCK;
+				break;
+			}
 			goto page_not_up_to_date;
+		}
 page_ok:
 
 		/* If users can be writing to this page using arbitrary
@@ -976,10 +987,10 @@ __generic_file_aio_read(struct kiocb *io
 			desc.error = 0;
 			do_generic_file_read(filp,ppos,&desc,file_read_actor);
 			retval += desc.written;
-			if (!retval) {
+			if (!retval)
 				retval = desc.error;
+			if (desc.written != iov[seg].iov_len)
 				break;
-			}
 		}
 	}
 out: