From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765246AbXEVCeS (ORCPT ); Mon, 21 May 2007 22:34:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759363AbXEVCeK (ORCPT ); Mon, 21 May 2007 22:34:10 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:53313 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759081AbXEVCeI (ORCPT ); Mon, 21 May 2007 22:34:08 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Andrew Morton Cc: Linus Torvalds , , Nick Piggin Subject: [PATCH 1/3] Preserve the dirty bit in init_page_buffers Date: Mon, 21 May 2007 20:31:50 -0600 Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The problem: When we are trying to free buffers try_to_free_buffers will look at ramdisk pages with clean buffer heads and remove the dirty bit from the page. Resulting in ramdisk pages with data that get removed from the page cache. Ouch! Buffer heads appear on ramdisk pages when a filesystem calls getblk, which through a series of function calls eventually calls init_page_buffers. So to fix the mismatch between buffer head state and page state this patch modifies init_page_buffers to transfer the dirty bit from the page to the buffer heads like we currently do for the uptodate bit. Signed-off-by: Eric W. Biederman --- fs/buffer.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index aa68206..c6b58e8 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -953,6 +953,7 @@ init_page_buffers(struct page *page, struct block_device *bdev, struct buffer_head *head = page_buffers(page); struct buffer_head *bh = head; int uptodate = PageUptodate(page); + int dirty = PageDirty(page); do { if (!buffer_mapped(bh)) { @@ -961,6 +962,8 @@ init_page_buffers(struct page *page, struct block_device *bdev, bh->b_blocknr = block; if (uptodate) set_buffer_uptodate(bh); + if (dirty) + set_buffer_dirty(bh); set_buffer_mapped(bh); } block++; -- 1.5.1.1.181.g2de0