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=-5.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, UNWANTED_LANGUAGE_BODY,URIBL_BLOCKED,USER_AGENT_MUTT 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 00B56C43382 for ; Thu, 27 Sep 2018 05:05:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A75782156B for ; Thu, 27 Sep 2018 05:05:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="XDQ3ex92" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A75782156B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1727289AbeI0LVb (ORCPT ); Thu, 27 Sep 2018 07:21:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:41616 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727268AbeI0LVa (ORCPT ); Thu, 27 Sep 2018 07:21:30 -0400 Received: from localhost (c-67-160-202-76.hsd1.ca.comcast.net [67.160.202.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B455721537; Thu, 27 Sep 2018 05:05:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1538024709; bh=pyi8GGnzN5sEqMWyKcMVUsILcsw2FP/KIdq2Bb2fU4o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XDQ3ex92COoPvzWA4sVGGvW8oRNywHmrnnOA2t+pydnZwIi/Ziz7P7q3isSYT+KYO NvURVE1oKjFUue7xsUtObh8PRvCETNYOoqPVIjg7YEvpYKCO5V9oP5WLfkhsFDzFbk WAazIe8Jr7cCdyp5UlyKXy0zILnU9d11vLpvUCX4= Date: Wed, 26 Sep 2018 22:05:09 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: Re: [PATCH] f2fs: refactor ->page_mkwrite() flow Message-ID: <20180927050509.GA72357@jaegeuk-macbookpro.roam.corp.google.com> References: <20180926144552.3302-1-chao@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180926144552.3302-1-chao@kernel.org> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This makes xfstests/083 stuck. So, I'll drop it for a while. 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