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=-10.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 C2A22C433E0 for ; Wed, 1 Jul 2020 02:38:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A804220771 for ; Wed, 1 Jul 2020 02:38:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726750AbgGACid (ORCPT ); Tue, 30 Jun 2020 22:38:33 -0400 Received: from foss.arm.com ([217.140.110.172]:41908 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725988AbgGACic (ORCPT ); Tue, 30 Jun 2020 22:38:32 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EEDA731B; Tue, 30 Jun 2020 19:38:31 -0700 (PDT) Received: from entos-d05.shanghai.arm.com (entos-d05.shanghai.arm.com [10.169.40.35]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id D4E723F73C; Tue, 30 Jun 2020 19:38:28 -0700 (PDT) From: Jianyong Wu To: ericvh@gmail.com, lucho@ionkov.net, asmadeus@codewreck.org, v9fs-developer@lists.sourceforge.net Cc: linux-kernel@vger.kernel.org, Steve.Capper@arm.com, Kaly.Xin@arm.com, justin.he@arm.com, jianyong.wu@arm.com, wei.chen@arm.com Subject: [PATCH v2] 9p: retrieve fid from file when file instance exist. Date: Wed, 1 Jul 2020 10:38:21 +0800 Message-Id: <20200701023821.5387-1-jianyong.wu@arm.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the current setattr implementation in 9p, fid is always retrieved from dentry no matter file instance exists or not. There may be some info related to opened file instance dropped. so it's better to retrieve fid from file instance if file instance is passed to setattr. for example: fd=open("tmp", O_RDWR); ftruncate(fd, 10); The file context related with fd will be lost as fid is always retrieved from dentry, then the backend can't get the info of file context. It is against the original intention of user and may lead to bug. Signed-off-by: Jianyong Wu --- fs/9p/vfs_inode.c | 6 +++++- fs/9p/vfs_inode_dotl.c | 6 +++++- 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c index c9255d399917..b33574d347fa 100644 --- a/fs/9p/vfs_inode.c +++ b/fs/9p/vfs_inode.c @@ -1100,7 +1100,11 @@ static int v9fs_vfs_setattr(struct dentry *dentry, struct iattr *iattr) retval = -EPERM; v9ses = v9fs_dentry2v9ses(dentry); - fid = v9fs_fid_lookup(dentry); + if (iattr->ia_valid & ATTR_FILE) { + fid = iattr->ia_file->private_data; + WARN_ON(!fid); + } else + fid = v9fs_fid_lookup(dentry); if(IS_ERR(fid)) return PTR_ERR(fid); diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c index 60328b21c5fb..ae714f1a630f 100644 --- a/fs/9p/vfs_inode_dotl.c +++ b/fs/9p/vfs_inode_dotl.c @@ -560,7 +560,11 @@ int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr) p9attr.mtime_sec = iattr->ia_mtime.tv_sec; p9attr.mtime_nsec = iattr->ia_mtime.tv_nsec; - fid = v9fs_fid_lookup(dentry); + if (iattr->ia_valid & ATTR_FILE) { + fid = iattr->ia_file->private_data; + WARN_ON(!fid); + } else + fid = v9fs_fid_lookup(dentry); if (IS_ERR(fid)) return PTR_ERR(fid); -- 2.17.1