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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 CCD08C432BE for ; Fri, 6 Aug 2021 09:43:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A851361040 for ; Fri, 6 Aug 2021 09:43:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244654AbhHFJn3 (ORCPT ); Fri, 6 Aug 2021 05:43:29 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:12461 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242680AbhHFJn2 (ORCPT ); Fri, 6 Aug 2021 05:43:28 -0400 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4Gh0n33x5wzckT3; Fri, 6 Aug 2021 17:39:35 +0800 (CST) Received: from dggema761-chm.china.huawei.com (10.1.198.203) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Fri, 6 Aug 2021 17:43:09 +0800 Received: from huawei.com (10.175.127.227) by dggema761-chm.china.huawei.com (10.1.198.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Fri, 6 Aug 2021 17:43:09 +0800 From: Zhihao Cheng To: , CC: , , , Subject: [PATCH] ovl: nfs_export: Parse index inode's nlink when 'd_inode(lowerdentry)->i_nlink == 1' Date: Fri, 6 Aug 2021 17:53:54 +0800 Message-ID: <20210806095354.2336263-1-chengzhihao1@huawei.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggema761-chm.china.huawei.com (10.1.198.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For overlayfs mounted by "nfs_export=on", all files/directories will be indexed regardless of whether 'nlink > 1' satisfies. Following process may cause breaking hard links on copy up: mkdir low upper work merge touch low/file mount -t overlay over -oupperdir=upper,lowerdir=low,workdir=work,nfs_export=on merge chmod +x merge/file # Now nlink of upper/file's correspoding index file equals to 2, and we have xattr "trusted.overlay.nlink=U-1" on upper/file echo 3 > /proc/sys/vm/drop_caches # merge/file's nlink changes to 2 For nfs_export enabled overlayfs, don't ignore parsing index inode's nlink when 'd_inode(lowerdentry)->i_nlink == 1'. Fixes: f168f1098dd9038 ("ovl: add support for "nfs_export" configuration") Signed-off-by: Zhihao Cheng --- fs/overlayfs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 5e828a1c98a8..75a61243371c 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -832,7 +832,8 @@ unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, char buf[13]; int err; - if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1) + if (!lowerdentry || !upperdentry || + (!ofs->config.nfs_export && d_inode(lowerdentry)->i_nlink == 1)) return fallback; err = ovl_do_getxattr(ofs, upperdentry, OVL_XATTR_NLINK, -- 2.31.1