From patchwork Mon May 24 22:28:06 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: gregkh@suse.de X-Patchwork-Id: 53477 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 8955AB7D52 for ; Tue, 25 May 2010 08:42:21 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758281Ab0EXWlh (ORCPT ); Mon, 24 May 2010 18:41:37 -0400 Received: from kroah.org ([198.145.64.141]:42336 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757150Ab0EXWiS (ORCPT ); Mon, 24 May 2010 18:38:18 -0400 Received: from localhost (c-24-16-163-131.hsd1.wa.comcast.net [24.16.163.131]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by coco.kroah.org (Postfix) with ESMTPSA id 195344851C; Mon, 24 May 2010 15:38:18 -0700 (PDT) X-Mailbox-Line: From gregkh@clark.site Mon May 24 15:30:16 2010 Message-Id: <20100524223016.208581966@clark.site> User-Agent: quilt/0.48-8.10 Date: Mon, 24 May 2010 15:28:06 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, linux-fsdevel@vger.kernel.org, Ext4 Developers List , "Theodore Tso" , "Jayson R. King" , "Aneesh Kumar K.V" Subject: [10/24] vfs: Add no_nrwrite_index_update writeback control flag In-Reply-To: <20100524223544.GA13721@kroah.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org 2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Aneesh Kumar K.V commit 17bc6c30cf6bfffd816bdc53682dd46fc34a2cf4 upstream. If no_nrwrite_index_update is set we don't update nr_to_write and address space writeback_index in write_cache_pages. This change enables a file system to skip these updates in write_cache_pages and do them in the writepages() callback. This patch will be followed by an ext4 patch that make use of these new flags. Signed-off-by: Aneesh Kumar K.V Signed-off-by: "Theodore Ts'o" CC: linux-fsdevel@vger.kernel.org [dev@jaysonking.com: Modified the patch to account for subsequent changes in mainline being cherry-picked earlier for 2.6.27.y.] Signed-off-by: Jayson R. King Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- include/linux/writeback.h | 9 +++++++++ mm/page-writeback.c | 14 +++++++++----- 2 files changed, 18 insertions(+), 5 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -62,6 +62,15 @@ struct writeback_control { unsigned for_writepages:1; /* This is a writepages() call */ unsigned range_cyclic:1; /* range_start is cyclic */ unsigned more_io:1; /* more io to be dispatched */ + /* + * write_cache_pages() won't update wbc->nr_to_write and + * mapping->writeback_index if no_nrwrite_index_update + * is set. write_cache_pages() may write more than we + * requested and we want to make sure nr_to_write and + * writeback_index are updated in a consistent manner + * so we use a single control to update them + */ + unsigned no_nrwrite_index_update:1; }; /* --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -878,6 +878,7 @@ int write_cache_pages(struct address_spa pgoff_t done_index; int cycled; int range_whole = 0; + long nr_to_write = wbc->nr_to_write; if (wbc->nonblocking && bdi_write_congested(bdi)) { wbc->encountered_congestion = 1; @@ -985,9 +986,9 @@ continue_unlock: } } - if (wbc->nr_to_write > 0) { - wbc->nr_to_write--; - if (wbc->nr_to_write == 0 && + if (nr_to_write > 0) { + nr_to_write--; + if (nr_to_write == 0 && wbc->sync_mode == WB_SYNC_NONE) { /* * We stop writing back only if we are @@ -1024,8 +1025,11 @@ continue_unlock: end = writeback_index - 1; goto retry; } - if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) - mapping->writeback_index = done_index; + if (!wbc->no_nrwrite_index_update) { + if (wbc->range_cyclic || (range_whole && nr_to_write > 0)) + mapping->writeback_index = done_index; + wbc->nr_to_write = nr_to_write; + } return ret; }