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=-15.2 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_SANE_1 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 F22AAC433E0 for ; Tue, 26 Jan 2021 20:15:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ABA3522255 for ; Tue, 26 Jan 2021 20:15:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732445AbhAZFXm (ORCPT ); Tue, 26 Jan 2021 00:23:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38670 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726991AbhAYJkW (ORCPT ); Mon, 25 Jan 2021 04:40:22 -0500 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD844C061352 for ; Mon, 25 Jan 2021 00:38:57 -0800 (PST) Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1l3xOi-0007V3-1o; Mon, 25 Jan 2021 09:38:56 +0100 Received: from sha by ptx.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1l3xOg-0008Hs-Lq; Mon, 25 Jan 2021 09:38:54 +0100 Date: Mon, 25 Jan 2021 09:38:54 +0100 From: Sascha Hauer To: Christoph Hellwig Cc: linux-fsdevel@vger.kernel.org, Richard Weinberger , linux-mtd@lists.infradead.org, kernel@pengutronix.de, Jan Kara Subject: Re: [PATCH 1/8] quota: Allow to pass mount path to quotactl Message-ID: <20210125083854.GB31738@pengutronix.de> References: <20210122151536.7982-1-s.hauer@pengutronix.de> <20210122151536.7982-2-s.hauer@pengutronix.de> <20210122171658.GA237653@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210122171658.GA237653@infradead.org> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 07:17:40 up 53 days, 18:44, 60 users, load average: 0.12, 0.09, 0.09 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: sha@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-fsdevel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Jan 22, 2021 at 05:16:58PM +0000, Christoph Hellwig wrote: > On Fri, Jan 22, 2021 at 04:15:29PM +0100, Sascha Hauer wrote: > > This patch introduces the Q_PATH flag to the quotactl cmd argument. > > When given, the path given in the special argument to quotactl will > > be the mount path where the filesystem is mounted, instead of a path > > to the block device. > > This is necessary for filesystems which do not have a block device as > > backing store. Particularly this is done for upcoming UBIFS support. > > > > Signed-off-by: Sascha Hauer > > I hate overloading quotactl even more. Why not add a new quotactl_path > syscall instead? We can probably do that. Honza, what do you think? > > > +static struct super_block *quotactl_sb(dev_t dev, int cmd) > > { > > struct super_block *sb; > > bool excl = false, thawed = false; > > > > if (quotactl_cmd_onoff(cmd)) { > > excl = true; > > @@ -901,12 +887,50 @@ static struct super_block *quotactl_block(const char __user *special, int cmd) > > goto retry; > > } > > return sb; > > +} > > + > > +/* > > + * look up a superblock on which quota ops will be performed > > + * - use the name of a block device to find the superblock thereon > > + */ > > +static struct super_block *quotactl_block(const char __user *special, int cmd) > > +{ > > +#ifdef CONFIG_BLOCK > > + struct filename *tmp = getname(special); > > + int error; > > + dev_t dev; > > > > + if (IS_ERR(tmp)) > > + return ERR_CAST(tmp); > > + error = lookup_bdev(tmp->name, &dev); > > + putname(tmp); > > + if (error) > > + return ERR_PTR(error); > > + > > + return quotactl_sb(dev, cmd); > > #else > > return ERR_PTR(-ENODEV); > > #endif > > Normal kernel style would be to keep the ifdef entirely outside the > function. It has been like this before, so changing this should be done in an extra patch. Not sure if it's worth it though. > > > +static struct super_block *quotactl_path(const char __user *special, int cmd) > > +{ > > + struct super_block *sb; > > + struct path path; > > + int error; > > + > > + error = user_path_at(AT_FDCWD, special, LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, > > + &path); > > This adds an overly long line. ok, will change. > > > + if (error) > > + return ERR_PTR(error); > > + > > + sb = quotactl_sb(path.mnt->mnt_sb->s_dev, cmd); > > I think quotactl_sb should take the superblock directly. This will > need a little refactoring of user_get_super, but will lead to much > better logic. What do you mean by "take"? Take the superblock as an argument to quotactl_sb() or take a reference to the superblock? Sorry, I don't really get where you aiming at. Sascha -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |