From patchwork Thu Dec 13 08:07:55 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Darrick Wong X-Patchwork-Id: 205777 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 714AD2C008D for ; Thu, 13 Dec 2012 19:10:30 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753232Ab2LMIJm (ORCPT ); Thu, 13 Dec 2012 03:09:42 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:17720 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753415Ab2LMIJj (ORCPT ); Thu, 13 Dec 2012 03:09:39 -0500 Received: from ucsinet21.oracle.com (ucsinet21.oracle.com [156.151.31.93]) by userp1040.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id qBD87xaI019073 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 13 Dec 2012 08:08:00 GMT Received: from acsmt358.oracle.com (acsmt358.oracle.com [141.146.40.158]) by ucsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id qBD87w9T021904 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 13 Dec 2012 08:07:58 GMT Received: from abhmt101.oracle.com (abhmt101.oracle.com [141.146.116.53]) by acsmt358.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id qBD87vnj011168; Thu, 13 Dec 2012 02:07:57 -0600 Received: from localhost (/67.171.138.228) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 13 Dec 2012 00:07:57 -0800 Subject: [PATCH 2/4] mm: Only enforce stable page writes if the backing device requires it To: axboe@kernel.dk, lucho@ionkov.net, jack@suse.cz, "Darrick J. Wong" , ericvh@gmail.com, viro@zeniv.linux.org.uk, rminnich@sandia.gov, tytso@mit.edu From: "Darrick J. Wong" Cc: martin.petersen@oracle.com, neilb@suse.de, david@fromorbit.com, Zheng Liu , linux-kernel@vger.kernel.org, hch@infradead.org, linux-fsdevel@vger.kernel.org, adilger.kernel@dilger.ca, bharrosh@panasas.com, jlayton@samba.org, v9fs-developer@lists.sourceforge.net, linux-ext4@vger.kernel.org Date: Thu, 13 Dec 2012 00:07:55 -0800 Message-ID: <20121213080755.23360.31463.stgit@blackbox.djwong.org> In-Reply-To: <20121213080740.23360.16346.stgit@blackbox.djwong.org> References: <20121213080740.23360.16346.stgit@blackbox.djwong.org> User-Agent: StGit/0.15 MIME-Version: 1.0 X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Create a helper function to check if a backing device requires stable page writes and, if so, performs the necessary wait. Then, make it so that all points in the memory manager that handle making pages writable use the helper function. This should provide stable page write support to most filesystems, while eliminating unnecessary waiting for devices that don't require the feature. Signed-off-by: Darrick J. Wong --- fs/buffer.c | 2 +- fs/ext4/inode.c | 2 +- include/linux/pagemap.h | 1 + mm/filemap.c | 3 ++- mm/page-writeback.c | 20 ++++++++++++++++++++ 5 files changed, 25 insertions(+), 3 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 diff --git a/fs/buffer.c b/fs/buffer.c index ec0aca8..c562136 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2363,7 +2363,7 @@ int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, if (unlikely(ret < 0)) goto out_unlock; set_page_dirty(page); - wait_on_page_writeback(page); + wait_for_stable_page(page); return 0; out_unlock: unlock_page(page); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index b3c243b..1bfc79f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4814,7 +4814,7 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, ext4_bh_unmapped)) { /* Wait so that we don't change page under IO */ - wait_on_page_writeback(page); + wait_for_stable_page(page); ret = VM_FAULT_LOCKED; goto out; } diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index e42c762..ea631ee 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -398,6 +398,7 @@ static inline void wait_on_page_writeback(struct page *page) } extern void end_page_writeback(struct page *page); +void wait_for_stable_page(struct page *page); /* * Add an arbitrary waiter to a page's wait queue diff --git a/mm/filemap.c b/mm/filemap.c index 83efee7..5577dc8 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1728,6 +1728,7 @@ int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) * see the dirty page and writeprotect it again. */ set_page_dirty(page); + wait_for_stable_page(page); out: sb_end_pagefault(inode->i_sb); return ret; @@ -2274,7 +2275,7 @@ repeat: return NULL; } found: - wait_on_page_writeback(page); + wait_for_stable_page(page); return page; } EXPORT_SYMBOL(grab_cache_page_write_begin); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 830893b..3e4a8cc 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2275,3 +2275,23 @@ int mapping_tagged(struct address_space *mapping, int tag) return radix_tree_tagged(&mapping->page_tree, tag); } EXPORT_SYMBOL(mapping_tagged); + +/** + * wait_for_stable_page() - wait for writeback to finish, if necessary. + * @page: The page to wait on. + * + * This function determines if the given page is related to a backing device + * that requires page contents to be held stable during writeback. If so, then + * it will wait for any pending writeback to complete. + */ +void wait_for_stable_page(struct page *page) +{ + struct address_space *mapping = page_mapping(page); + struct backing_dev_info *bdi = mapping->backing_dev_info; + + if (!bdi_cap_stable_pages_required(bdi)) + return; + + wait_on_page_writeback(page); +} +EXPORT_SYMBOL_GPL(wait_for_stable_page);