[PATCH] end_buffer_async_read printk ratelimiting

ratelimit the disk I/O error reporting in end_buffer_async_read().
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/buffer.c

@@ -550,7 +550,8 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate)
 		set_buffer_uptodate(bh);
 	} else {
 		clear_buffer_uptodate(bh);
-		buffer_io_error(bh);
+		if (printk_ratelimit())
+			buffer_io_error(bh);
 		SetPageError(page);
 	}