From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EAE92C43382 for ; Thu, 27 Sep 2018 05:48:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A19B921537 for ; Thu, 27 Sep 2018 05:48:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A19B921537 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727240AbeI0MEm (ORCPT ); Thu, 27 Sep 2018 08:04:42 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:51846 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726687AbeI0MEm (ORCPT ); Thu, 27 Sep 2018 08:04:42 -0400 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 9DDC7721F3921; Thu, 27 Sep 2018 13:48:09 +0800 (CST) Received: from [127.0.0.1] (10.134.22.195) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.399.0; Thu, 27 Sep 2018 13:48:09 +0800 Subject: Re: [PATCH] f2fs: refactor ->page_mkwrite() flow To: Jaegeuk Kim , Chao Yu CC: , References: <20180926144552.3302-1-chao@kernel.org> <20180927050509.GA72357@jaegeuk-macbookpro.roam.corp.google.com> From: Chao Yu Message-ID: <3bed1658-e24a-c114-3079-62f444c613bc@huawei.com> Date: Thu, 27 Sep 2018 13:48:08 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180927050509.GA72357@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018/9/27 13:05, Jaegeuk Kim wrote: > This makes xfstests/083 stuck. So, I'll drop it for a while. Alright, let me check that case again. Thanks, > > On 09/26, Chao Yu wrote: >> From: Chao Yu >> >> Thread A Thread B >> - f2fs_vm_page_mkwrite >> - f2fs_setattr >> - down_write(i_mmap_sem) >> - truncate_setsize >> - f2fs_truncate >> - up_write(i_mmap_sem) >> - f2fs_reserve_block >> reserve NEW_ADDR >> - skip dirty page due to truncation >> >> 1. we don't need to rserve new block address for a truncated page. >> 2. dn.data_blkaddr is used out of node page lock coverage. >> >> Refactor ->page_mkwrite() flow to fix above issues: >> - use __do_map_lock() to avoid racing checkpoint() >> - lock data page in prior to dnode page >> - cover f2fs_reserve_block with i_mmap_sem lock >> - access dn.data_blkaddr under dnode lock >> >> Signed-off-by: Chao Yu >> --- >> fs/f2fs/file.c | 29 ++++++++++++++--------------- >> 1 file changed, 14 insertions(+), 15 deletions(-) >> >> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >> index 6f02c8daff76..fcb4788b48aa 100644 >> --- a/fs/f2fs/file.c >> +++ b/fs/f2fs/file.c >> @@ -47,7 +47,7 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf) >> struct page *page = vmf->page; >> struct inode *inode = file_inode(vmf->vma->vm_file); >> struct f2fs_sb_info *sbi = F2FS_I_SB(inode); >> - struct dnode_of_data dn; >> + struct dnode_of_data dn = { .node_changed = false }; >> int err; >> >> if (unlikely(f2fs_cp_error(sbi))) { >> @@ -59,19 +59,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf) >> >> f2fs_bug_on(sbi, f2fs_has_inline_data(inode)); >> >> - /* block allocation */ >> - f2fs_lock_op(sbi); >> - set_new_dnode(&dn, inode, NULL, NULL, 0); >> - err = f2fs_reserve_block(&dn, page->index); >> - if (err) { >> - f2fs_unlock_op(sbi); >> - goto out; >> - } >> - f2fs_put_dnode(&dn); >> - f2fs_unlock_op(sbi); >> - >> - f2fs_balance_fs(sbi, dn.node_changed); >> - >> file_update_time(vmf->vma->vm_file); >> down_read(&F2FS_I(inode)->i_mmap_sem); >> lock_page(page); >> @@ -108,12 +95,24 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf) >> /* fill the page */ >> f2fs_wait_on_page_writeback(page, DATA, false); >> >> + /* block allocation */ >> + __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true); >> + set_new_dnode(&dn, inode, NULL, NULL, 0); >> + err = f2fs_reserve_block(&dn, page->index); >> + if (err) >> + goto out_unlock; >> + >> /* wait for GCed page writeback via META_MAPPING */ >> f2fs_wait_on_block_writeback(inode, dn.data_blkaddr); >> >> + f2fs_put_dnode(&dn); >> +out_unlock: >> + __do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false); >> out_sem: >> up_read(&F2FS_I(inode)->i_mmap_sem); >> -out: >> + >> + f2fs_balance_fs(sbi, dn.node_changed); >> + >> sb_end_pagefault(inode->i_sb); >> f2fs_update_time(sbi, REQ_TIME); >> err: >> -- >> 2.18.0 > > . >