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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D4ADAC4347E for ; Mon, 21 Sep 2020 17:46:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9968B2151B for ; Mon, 21 Sep 2020 17:46:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728109AbgIURqZ (ORCPT ); Mon, 21 Sep 2020 13:46:25 -0400 Received: from mx2.suse.de ([195.135.220.15]:59124 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726537AbgIURqZ (ORCPT ); Mon, 21 Sep 2020 13:46:25 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C03BCAC23; Mon, 21 Sep 2020 17:47:00 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id AD197DA6E0; Mon, 21 Sep 2020 19:45:09 +0200 (CEST) Date: Mon, 21 Sep 2020 19:45:09 +0200 From: David Sterba To: Nikolay Borisov Cc: linux-btrfs@vger.kernel.org Subject: Re: [PATCH 1/7] btrfs: Don't call readpage_end_io_hook for the btree inode Message-ID: <20200921174509.GN6756@twin.jikos.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, Nikolay Borisov , linux-btrfs@vger.kernel.org References: <20200918133439.23187-1-nborisov@suse.com> <20200918133439.23187-2-nborisov@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918133439.23187-2-nborisov@suse.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Fri, Sep 18, 2020 at 04:34:33PM +0300, Nikolay Borisov wrote: > Instead of relying on indirect calls to implement metadata buffer > validation simply check if the inode whose page we are processing equals > the btree inode. If it does call the necessary function. > > This is an improvement in 2 directions: > 1. We aren't paying the penalty of indirect calls in a post-speculation > attacks world. > > 2. The function is now named more explicitly so it's obvious what's > going on The new naming is not making things clear, btrfs_check_csum sounds very generic while it does a very specific thing just by the number and type of the parameters. Similar for btrfs_validate_metadata_buffer. > --- a/fs/btrfs/extent_io.c > +++ b/fs/btrfs/extent_io.c > @@ -2851,9 +2851,12 @@ static void end_bio_extent_readpage(struct bio *bio) > > mirror = io_bio->mirror_num; > if (likely(uptodate)) { > - ret = tree->ops->readpage_end_io_hook(io_bio, offset, > - page, start, end, > - mirror); > + if (data_inode) > + ret = btrfs_check_csum(io_bio, offset, page, > + start, end, mirror); > + else > + ret = btrfs_validate_metadata_buffer(io_bio, > + offset, page, start, end, mirror); In the context where the functions are used I'd expect some symmetry, data/metadata. Something like btrfs_validate_data_bio.