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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 DDEE0C433E1 for ; Wed, 24 Mar 2021 05:03:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BCB4619E8 for ; Wed, 24 Mar 2021 05:03:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235198AbhCXFCa (ORCPT ); Wed, 24 Mar 2021 01:02:30 -0400 Received: from zeniv-ca.linux.org.uk ([142.44.231.140]:40672 "EHLO zeniv-ca.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232648AbhCXFCN (ORCPT ); Wed, 24 Mar 2021 01:02:13 -0400 Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94 #2 (Red Hat Linux)) id 1lOvel-008keX-JS; Wed, 24 Mar 2021 05:02:11 +0000 Date: Wed, 24 Mar 2021 05:02:11 +0000 From: Al Viro To: Miklos Szeredi Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig Subject: Re: [PATCH v2 01/18] vfs: add miscattr ops Message-ID: References: <20210322144916.137245-1-mszeredi@redhat.com> <20210322144916.137245-2-mszeredi@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210322144916.137245-2-mszeredi@redhat.com> Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 22, 2021 at 03:48:59PM +0100, Miklos Szeredi wrote: minor nit: copy_fsxattr_{to,from}_user() might be better. > +int fsxattr_copy_to_user(const struct miscattr *ma, struct fsxattr __user *ufa) > +{ > + struct fsxattr fa = { > + .fsx_xflags = ma->fsx_xflags, > + .fsx_extsize = ma->fsx_extsize, > + .fsx_nextents = ma->fsx_nextents, > + .fsx_projid = ma->fsx_projid, > + .fsx_cowextsize = ma->fsx_cowextsize, > + }; That wants a comment along the lines of "guaranteed to be gap-free", since otherwise you'd need memset() to avoid an infoleak. > +static int ioctl_getflags(struct file *file, void __user *argp) > +{ > + struct miscattr ma = { .flags_valid = true }; /* hint only */ > + unsigned int flags; > + int err; > + > + err = vfs_miscattr_get(file_dentry(file), &ma); Umm... Just to clarify - do we plan to have that ever called via ovl_real_ioctl()? IOW, is file_dentry() anything other than a way to spell ->f_path.dentry here? > +struct miscattr { > + u32 flags; /* flags (FS_IOC_GETFLAGS/FS_IOC_SETFLAGS) */ > + /* struct fsxattr: */ > + u32 fsx_xflags; /* xflags field value (get/set) */ > + u32 fsx_extsize; /* extsize field value (get/set)*/ > + u32 fsx_nextents; /* nextents field value (get) */ > + u32 fsx_projid; /* project identifier (get/set) */ > + u32 fsx_cowextsize; /* CoW extsize field value (get/set)*/ > + /* selectors: */ > + bool flags_valid:1; > + bool xattr_valid:1; > +}; OK as long as it stays kernel-only, but if we ever expose that to userland, we'd better remember to turn the last two into an u32 with explicit bitmasks.