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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E73CFC83F15 for ; Tue, 29 Aug 2023 02:06:27 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 610C38E001F; Mon, 28 Aug 2023 22:06:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5C0AC8E001E; Mon, 28 Aug 2023 22:06:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4D7A88E001F; Mon, 28 Aug 2023 22:06:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 42C548E001E for ; Mon, 28 Aug 2023 22:06:27 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 11E671405CF for ; Tue, 29 Aug 2023 02:06:27 +0000 (UTC) X-FDA: 81175502814.28.E73E96C Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) by imf25.hostedemail.com (Postfix) with ESMTP id 24F1FA0011 for ; Tue, 29 Aug 2023 02:06:24 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=linux.org.uk header.s=zeniv-20220401 header.b=wNWIUkcs; dmarc=pass (policy=none) header.from=zeniv.linux.org.uk; spf=none (imf25.hostedemail.com: domain of viro@ftp.linux.org.uk has no SPF policy when checking 62.89.141.173) smtp.mailfrom=viro@ftp.linux.org.uk ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1693274785; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=oP8fj38bboms1uJShzDU6mgwe9sKE93KOrcjUMBNZME=; b=DEZfjYEUrK/XrIJehiLlOY/+ZhJqj9LZ7xI+Ecq0kY51xjQEwSGhBJBXT4qotb4Azre9Ui aMFA7SkSxZHqoN6W/IDqaW8WYHyi++TSJ62rW69l8Pn/bGospgPkmOmLpBI3n2KtEVXNtC mVltoboZQcbGNiW7f08HX7UndWeLsCQ= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=linux.org.uk header.s=zeniv-20220401 header.b=wNWIUkcs; dmarc=pass (policy=none) header.from=zeniv.linux.org.uk; spf=none (imf25.hostedemail.com: domain of viro@ftp.linux.org.uk has no SPF policy when checking 62.89.141.173) smtp.mailfrom=viro@ftp.linux.org.uk ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1693274785; a=rsa-sha256; cv=none; b=U+H8iU8DIqSLSdAblHtKrqCEUgQu0Jj5xqv0vYR74Pa4XbMcrHnSEZyc+ZYlOIHnyrq+Ae R3iHFsGWgIltaI9QMsi3R725cpkDwoiDsXrcufCOY5xCUYCPE+LCxNqydDYdH7VPBJZ78f x1iR2BpexWOcoCzNwdo77SGE8d+W/8k= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=oP8fj38bboms1uJShzDU6mgwe9sKE93KOrcjUMBNZME=; b=wNWIUkcs/45QgUJmsxczuJiN/R F4wMLEpXMoZeBRGNwBwe+F5GOwBpBQ3tQnTuvGh52vY1ZObxB/YOD8AtOPrrFN44xwn/zpDwwjliC Wt3W6iJnKUmQsDRKIqSiVQIC7Q7nCTwbegbPk4J0tP3CWh6Y6WKRWvv9P4YHldm/0d9DHitAV2vD7 sHOMwc/+XMDIppwQNMA7yGVj6vqWEq9uK5JU0mix8dCE5kZ/a0U3xOxlJcWUacAAnMqdEbSRq5SIg uNbxl4HTndR74wrJ2AoeW7KprnfHZ/wRMKXGGdh+4d9C7VWqp1u9KV5vpA1IEwURws97ihtiAQ23F l4VEy+ow==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.96 #2 (Red Hat Linux)) id 1qao7S-001i1V-2b; Tue, 29 Aug 2023 02:06:14 +0000 Date: Tue, 29 Aug 2023 03:06:14 +0100 From: Al Viro To: Christoph Hellwig Cc: Jens Axboe , "Darrick J. Wong" , Andrew Morton , Matthew Wilcox , Christian Brauner , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/6] block: open code __generic_file_write_iter for blkdev writes Message-ID: <20230829020614.GB325446@ZenIV> References: <20230801172201.1923299-1-hch@lst.de> <20230801172201.1923299-4-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230801172201.1923299-4-hch@lst.de> X-Rspamd-Queue-Id: 24F1FA0011 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: awf11bmwgxgs7hatesf1buoendg9jea3 X-HE-Tag: 1693274784-23457 X-HE-Meta: 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 ZWaUvAB4 SxcfHldnapvBl++wfmOBgDyZ/j9sHZD6YZP8ImzPOTfprVtNu9XfattfG8HF2v0hbg7GmDwcHNMxu+spGYBvkjfqndH+lk7OikyOPRGn0+6yMB5LuIUSvis/UlC5RwDc4Tc4OmrNAyHIzYGDIZwyACGm5qVP7f7kp5Ai5sv224xLrrKZS97ldtxxn4ox7+Ac6Cw97DAtIEtNnwoxNcIUAf6AeDhi6ECkx0VwByS54man+gNPHNykvlIASg8Y5sRhzK/PNHT3qBvwfqViH3uNk/W0F5xmNhQrYYwnXRl4Qg/mTMryBLLEtSMN4RL6Ljs6Gw2Y7ReGWW/s69yoYS0DZcrmOkIvBLPjXvzvSJ3VMfaJmi/5MQOWWO3TsSqvhcRP6Me48calEqKtUVtR80AbsoPIwV0qtAdLoyE8SGYPoso+/oyVwBUHhVDeK/yB4zi+39UzZ84XebHz/1yorc682QFQp2Fucw4qhJ12YRa7h6FBVB5A= 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: On Tue, Aug 01, 2023 at 07:21:58PM +0200, Christoph Hellwig wrote: > @@ -569,7 +594,23 @@ static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) > iov_iter_truncate(from, size); > } > > - ret = __generic_file_write_iter(iocb, from); > + ret = file_remove_privs(file); > + if (ret) > + return ret; That chunk is a bit of a WTF generator... Thankfully, static int __file_remove_privs(struct file *file, unsigned int flags) { struct dentry *dentry = file_dentry(file); struct inode *inode = file_inode(file); int error = 0; int kill; if (IS_NOSEC(inode) || !S_ISREG(inode->i_mode)) return 0; means that it's really a no-op. But I'd still suggest removing it, just to reduce the amount of head-scratching for people who'll be reading that code later...