From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753595Ab2GWBnm (ORCPT ); Sun, 22 Jul 2012 21:43:42 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:54427 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753127Ab2GWBnh (ORCPT ); Sun, 22 Jul 2012 21:43:37 -0400 Message-Id: <20120723010657.832081209@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 23 Jul 2012 02:07:33 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Bob Liu , Hugh Dickins , David Howells , Geert Uytterhoeven , Greg Ungerer Subject: [ 042/108] fs: ramfs: file-nommu: add SetPageUptodate() In-Reply-To: <20120723010651.408577075@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bob Liu commit fea9f718b3d68147f162ed2d870183ce5e0ad8d8 upstream. There is a bug in the below scenario for !CONFIG_MMU: 1. create a new file 2. mmap the file and write to it 3. read the file can't get the correct value Because sys_read() -> generic_file_aio_read() -> simple_readpage() -> clear_page() which causes the page to be zeroed. Add SetPageUptodate() to ramfs_nommu_expand_for_mapping() so that generic_file_aio_read() do not call simple_readpage(). Signed-off-by: Bob Liu Cc: Hugh Dickins Cc: David Howells Cc: Geert Uytterhoeven Cc: Greg Ungerer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- fs/ramfs/file-nommu.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c index fbb0b47..d5378d0 100644 --- a/fs/ramfs/file-nommu.c +++ b/fs/ramfs/file-nommu.c @@ -110,6 +110,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize) /* prevent the page from being discarded on memory pressure */ SetPageDirty(page); + SetPageUptodate(page); unlock_page(page); put_page(page);