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Wong" X-Patchwork-Id: 10816077 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ECB691575 for ; Fri, 15 Feb 2019 22:40:05 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D1B8D2ECA8 for ; Fri, 15 Feb 2019 22:40:05 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BF1802FD74; Fri, 15 Feb 2019 22:40:05 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0C4D82ECA8 for ; Fri, 15 Feb 2019 22:40:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DFBD98E0006; Fri, 15 Feb 2019 17:40:03 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id DAAC48E0001; Fri, 15 Feb 2019 17:40:03 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BFF578E0006; Fri, 15 Feb 2019 17:40:03 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id 774538E0001 for ; Fri, 15 Feb 2019 17:40:03 -0500 (EST) Received: by mail-pg1-f199.google.com with SMTP id a2so7771164pgt.11 for ; Fri, 15 Feb 2019 14:40:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:date:from:to:cc:subject :message-id:references:mime-version:content-disposition:in-reply-to :user-agent; bh=rFBuPAUp3qyHrOOVnWy4HHWdGelJ0ySma1MEojBeK4Y=; b=HzneaFNW69dcTaOuN42ChC3ZfsXiBGuEUCXcgdnEpUxZy1FXQOGJ+XM11K+qDF7qQK 7KlMEiBWfJCmwrv+wfuyhr5wX1ZhYE+48e62fOKL+76Kcfe0fOuyZWOq49n0iGxErjAt zwa7cC/ZfASpL55M/x9XOE7VIY22k3qs5K6JjzeeOKYlasXsW3U8sVZ2f2Twn9q1WRfj KviYV1xv7OjwwYQV169nlMFs8qO3sAELB6pURgf41PGrP26rNKV1E4k/Q7MHMmbcvhCT TA2iJCKZ8Ep1hlWz0uudbUVY+wpzagbJH+IjT0SnUkWAyLfpakbtPhersMMfU2hT5APe 8KrA== X-Gm-Message-State: AHQUAuZFhj01Oshqej/chnva385qEeIbwSOWgJPa+aYWcm2rIWvnqmm/ P7Drom0ujFDgwfChhAVigopaDbwGei1px6LSzYZEx94dt9jbdX8PLQWNkk/ijCm3C/QIYsK5U4e UXelWoP0PC4pfG6en714PjaVrduZcH/5vpUjKSO1BHobNlqXmnwMfRVNBZYNDXb+npw== X-Received: by 2002:a63:ca:: with SMTP id 193mr8434567pga.288.1550270403122; Fri, 15 Feb 2019 14:40:03 -0800 (PST) X-Google-Smtp-Source: AHgI3IbW138uaNNJtSpKvdNgOvPxJhCf4MECoNGXeHhFYFytF5NWOi3iN03Xddd2AAPZ1SRNQwfL X-Received: by 2002:a63:ca:: with SMTP id 193mr8434518pga.288.1550270402162; Fri, 15 Feb 2019 14:40:02 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1550270402; cv=none; d=google.com; s=arc-20160816; b=cUYC3WBtpjyGbJT90oC+Zb7Al3fqmOm3/y8tWB4/bYYoqUXdw2WT4UPAhd80UM92/h xUJltCG/hujwKuyv8y56hwK6nl57joqCj+Kb1BqKDgnPYAhGG8zWIWRRWzJZ2jViJqfZ whMbOY87nCJKKviaFPl+Rf5zbaX88vQ0f+bdhsHPeK6n5E/RyOc7cAgDY50hMttXR0ii p06qZ0++kXiXocdBR2jbWpnBnsP//d8rtgpco+n7tQdkb4qaBhsJNSMPL+bgv/10nBzZ dZwTAJXCFlR8xa7E5sl6RQ+ovSbOi4RrsAlTxvEr/IaaNZoIqwWCm/BPbClKtGpodFMl uXkA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature; bh=rFBuPAUp3qyHrOOVnWy4HHWdGelJ0ySma1MEojBeK4Y=; b=wpLYQ4d6XqrO2hAJGGXX6bKiopQtysgTbcuxUfi4ZMA5+Aibo7q7WANALjBwLnJGLy KEWCPd1JzjXMhDyloXEHyRHYNKDt+v9pOsVagovTilrduowM7mOqLmy57CIGN3Lme1nL SgKaYBemiz9TRfRX6QhbncG4/VCLd9Qlz8lKM/z7zimPK2q7AdQ7n4l05CZA6Ze4bMgd hfaMQRv699G1pKV7B5A1D6O/X4FWfrvdr0DouOdu+b94gwY83qQ7XV7NdvQ8pSS9tQT9 E3Xwc99OkAIK6yfsgk9fzkIPJ4OEBNTgjTvLwVDE8KYL6zl9qfntV3GWshvt8vvZo7vY xoxw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=DlWuhRsQ; spf=pass (google.com: domain of darrick.wong@oracle.com designates 156.151.31.86 as permitted sender) smtp.mailfrom=darrick.wong@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from userp2130.oracle.com (userp2130.oracle.com. [156.151.31.86]) by mx.google.com with ESMTPS id r10si6253289pgr.489.2019.02.15.14.40.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Feb 2019 14:40:02 -0800 (PST) Received-SPF: pass (google.com: domain of darrick.wong@oracle.com designates 156.151.31.86 as permitted sender) client-ip=156.151.31.86; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=DlWuhRsQ; spf=pass (google.com: domain of darrick.wong@oracle.com designates 156.151.31.86 as permitted sender) smtp.mailfrom=darrick.wong@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x1FMcxWe146163; Fri, 15 Feb 2019 22:39:37 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=rFBuPAUp3qyHrOOVnWy4HHWdGelJ0ySma1MEojBeK4Y=; b=DlWuhRsQN5kmw/90osRqZIUez1X7TeWVRLI7Kmo3JJLaKkBIv/m6V3c1AfzbcvH/Fbv+ Pat6xx5UMyo9oCVRyHCxwxWw36YcaWzwhLQybvwJNUtbYmWmiDXFFunEW33PVOvPUoXA QXGfkWN/0Z9F0oJjJtCSx3wAragBKmNc9NDTbsAQzGrHgvDE+dmf6X1MnccK3sZSLsqd y414B1CWKpfaaRFfeNsWyrhr3YsdHnUhXpCyIumo1j6uZgNE0s/q0K3/QUb07LBRYli/ hXX4XlAFW5Ylxq3u/f3kV4GyW9T6f6uyQXsPYlFhYDrSG1WTLIp47m4Jj7sPgUTCu9mn 5A== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2130.oracle.com with ESMTP id 2qhrem0cbf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 15 Feb 2019 22:39:36 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x1FMdTnq026520 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 15 Feb 2019 22:39:30 GMT Received: from abhmp0022.oracle.com (abhmp0022.oracle.com [141.146.116.28]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x1FMdR7l015082; Fri, 15 Feb 2019 22:39:28 GMT Received: from localhost (/10.145.178.102) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 15 Feb 2019 14:39:27 -0800 Date: Fri, 15 Feb 2019 14:39:25 -0800 From: "Darrick J. Wong" To: clm@fb.com, josef@toxicpanda.com, dsterba@suse.com, viro@zeniv.linux.org.uk, jack@suse.com, tytso@mit.edu, adilger.kernel@dilger.ca, jaegeuk@kernel.org, yuchao0@huawei.com, hughd@google.com, hch@infradead.org Cc: richard@nod.at, dedekind1@gmail.com, adrian.hunter@intel.com, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, linux-mm@kvack.org, amir73il@gmail.com Subject: [PATCH v2] vfs: don't decrement i_nlink in d_tmpfile Message-ID: <20190215223925.GO32253@magnolia> References: <20190214234908.GA6474@magnolia> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190214234908.GA6474@magnolia> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9168 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=831 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902150147 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Darrick J. Wong d_tmpfile was introduced to instantiate an inode in the dentry cache as a temporary file. This helper decrements the inode's nlink count and dirties the inode, presumably so that filesystems could call new_inode to create a new inode with nlink == 1 and then call d_tmpfile which will decrement nlink. However, this doesn't play well with XFS, which needs to allocate, initialize, and insert a tempfile inode on its unlinked list in a single transaction. In order to maintain referential integrity of the XFS metadata, we cannot have an inode on the unlinked list with nlink >= 1. XFS and btrfs hack around d_tmpfile's behavior by creating the inode with nlink == 0 and then incrementing it just prior to calling d_tmpfile, anticipating that it will be reset to 0. Everywhere else, it appears that nlink updates and persistence is the responsibility of individual filesystems. Therefore, move the nlink decrement out of d_tmpfile into the callers, and require that callers only pass in inodes with nlink already set to 0. Signed-off-by: Darrick J. Wong --- v2: convert BUG_ON to WARN_ON per review comment --- fs/btrfs/inode.c | 8 -------- fs/dcache.c | 10 ++++++---- fs/ext2/namei.c | 2 +- fs/ext4/namei.c | 1 + fs/f2fs/namei.c | 1 + fs/minix/namei.c | 2 +- fs/ubifs/dir.c | 1 + fs/udf/namei.c | 2 +- fs/xfs/xfs_iops.c | 13 ++----------- mm/shmem.c | 1 + 10 files changed, 15 insertions(+), 26 deletions(-) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 5c349667c761..bd189fc50f83 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -10382,14 +10382,6 @@ static int btrfs_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) if (ret) goto out; - /* - * We set number of links to 0 in btrfs_new_inode(), and here we set - * it to 1 because d_tmpfile() will issue a warning if the count is 0, - * through: - * - * d_tmpfile() -> inode_dec_link_count() -> drop_nlink() - */ - set_nlink(inode, 1); d_tmpfile(dentry, inode); unlock_new_inode(inode); mark_inode_dirty(inode); diff --git a/fs/dcache.c b/fs/dcache.c index aac41adf4743..bb349d423055 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -3042,12 +3042,14 @@ void d_genocide(struct dentry *parent) EXPORT_SYMBOL(d_genocide); +/* + * Instantiate an inode in the dentry cache as a temporary file. Callers must + * ensure that @inode has a zero link count. + */ void d_tmpfile(struct dentry *dentry, struct inode *inode) { - inode_dec_link_count(inode); - BUG_ON(dentry->d_name.name != dentry->d_iname || - !hlist_unhashed(&dentry->d_u.d_alias) || - !d_unlinked(dentry)); + WARN_ON(dentry->d_name.name != dentry->d_iname || + !d_unlinked(dentry) || inode->i_nlink != 0); spin_lock(&dentry->d_parent->d_lock); spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); dentry->d_name.len = sprintf(dentry->d_iname, "#%llu", diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c index 0c26dcc5d850..8542e9ce9677 100644 --- a/fs/ext2/namei.c +++ b/fs/ext2/namei.c @@ -117,7 +117,7 @@ static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) return PTR_ERR(inode); ext2_set_file_ops(inode); - mark_inode_dirty(inode); + inode_dec_link_count(inode); d_tmpfile(dentry, inode); unlock_new_inode(inode); return 0; diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 2b928eb07fa2..7502432f9816 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2517,6 +2517,7 @@ static int ext4_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) inode->i_op = &ext4_file_inode_operations; inode->i_fop = &ext4_file_operations; ext4_set_aops(inode); + inode_dec_link_count(inode); d_tmpfile(dentry, inode); err = ext4_orphan_add(handle, inode); if (err) diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c index 62d9829f3a6a..31a556af5f3a 100644 --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -780,6 +780,7 @@ static int __f2fs_tmpfile(struct inode *dir, struct dentry *dentry, f2fs_i_links_write(inode, false); *whiteout = inode; } else { + inode_dec_link_count(inode); d_tmpfile(dentry, inode); } /* link_count was changed by d_tmpfile as well. */ diff --git a/fs/minix/namei.c b/fs/minix/namei.c index 1a6084d2b02e..3249f86c476a 100644 --- a/fs/minix/namei.c +++ b/fs/minix/namei.c @@ -57,7 +57,7 @@ static int minix_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) struct inode *inode = minix_new_inode(dir, mode, &error); if (inode) { minix_set_inode(inode, 0); - mark_inode_dirty(inode); + inode_dec_link_count(inode); d_tmpfile(dentry, inode); } return error; diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 5767b373a8ff..7187e4fd7561 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -419,6 +419,7 @@ static int do_tmpfile(struct inode *dir, struct dentry *dentry, drop_nlink(inode); *whiteout = inode; } else { + inode_dec_link_count(inode); d_tmpfile(dentry, inode); } ubifs_assert(c, ui->dirty); diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 58cc2414992b..38bd021f9673 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -652,7 +652,7 @@ static int udf_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) inode->i_data.a_ops = &udf_aops; inode->i_op = &udf_file_inode_operations; inode->i_fop = &udf_file_operations; - mark_inode_dirty(inode); + inode_dec_link_count(inode); d_tmpfile(dentry, inode); unlock_new_inode(inode); return 0; diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index 1efef69a7f1c..f48ffd7a8d3e 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c @@ -191,18 +191,9 @@ xfs_generic_create( xfs_setup_iops(ip); - if (tmpfile) { - /* - * The VFS requires that any inode fed to d_tmpfile must have - * nlink == 1 so that it can decrement the nlink in d_tmpfile. - * However, we created the temp file with nlink == 0 because - * we're not allowed to put an inode with nlink > 0 on the - * unlinked list. Therefore we have to set nlink to 1 so that - * d_tmpfile can immediately set it back to zero. - */ - set_nlink(inode, 1); + if (tmpfile) d_tmpfile(dentry, inode); - } else + else d_instantiate(dentry, inode); xfs_finish_inode_setup(ip); diff --git a/mm/shmem.c b/mm/shmem.c index 6ece1e2fe76e..4a7810093561 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2818,6 +2818,7 @@ shmem_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) error = simple_acl_create(dir, inode); if (error) goto out_iput; + inode_dec_link_count(inode); d_tmpfile(dentry, inode); } return error;