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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 68F7EC4338F for ; Wed, 18 Aug 2021 23:22:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 391B56109F for ; Wed, 18 Aug 2021 23:22:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233928AbhHRXXR (ORCPT ); Wed, 18 Aug 2021 19:23:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232862AbhHRXXR (ORCPT ); Wed, 18 Aug 2021 19:23:17 -0400 Received: from mail-pl1-x635.google.com (mail-pl1-x635.google.com [IPv6:2607:f8b0:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA3B4C061764 for ; Wed, 18 Aug 2021 16:22:41 -0700 (PDT) Received: by mail-pl1-x635.google.com with SMTP id u1so2860634plr.1 for ; Wed, 18 Aug 2021 16:22:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=+znUywaHilSFMMJv1Y4x6bPgrIgLTXv2SL6EryarGL4=; b=oN8xGTXErQBtLx4G6V7cFe5OoJZukmO3qn9co/wHlN18fel6V43GUhk/uKYe2JXM6l 1ikF9Hk2xMgX0gOAe5u0IFUdVLJp8xR3rPuUWU837C52vjZv5pfx+9WTmgzXXguKBS1X azaXFrfNtEqvY5CJsh+O3d7rPPBOBxDFNivPK7Coi5L2YS0zMcDvFovNJeGw0/YtbKHa VxNA+IxysDfZvYfPAHfXRnBhCn1ZKbfKYmB14OLSSRwjdJ+VdRmZzw6eRoyL2m032Hg7 epJQcFDvrvBf4uJUNfWeeKSwDIUHHGdGDzG4NjEX7sjpTNSdZVDdsOyPl14mTUEBYidl tJqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=+znUywaHilSFMMJv1Y4x6bPgrIgLTXv2SL6EryarGL4=; b=tLLBAKzTlwOrNCm+vzAOmeJM+iZd1w0vmIJ4qgdYBWoDDJYmV/gSh6ZfUrCyGcr5i5 5JOJSMKtkMZtEB6HWFN69uiJ47vwmOFGj3EeOPvPkV9+Mtv1Q7XBcHpf5jpC2IKnTD+o 374sjfo1Pj4fGFudjlbwQDabOYhXiiAQ1Gx8ObuBOxfoqlTMiKk5dpAn94PWdC4ho+6f rHQuumm8N8o2Bn17hW7PniIddCP5talUKQ53iVHrWoO9/UH9fz3ToKxmAnjlIiEB2Rn9 2CoBBhu0uBy4dI3jsua7NkN97DgNVSt9NjIysScl9ziuPQlWnVXrGLCfKvaxSv2Vey25 Xg4g== X-Gm-Message-State: AOAM533B7qTQ2mX27imIt6P4vjsolmBPJA7AyX69ELtIIbZ5Faf6+jyU wl0hYSsqHGguvGHD9apF/mE= X-Google-Smtp-Source: ABdhPJwarObRRCLuec++WEYMOMWDJqBwgrK5fbeWTNXcqyaMKxU4R2amg0VUWAGG/NMEAMoD8YmLuQ== X-Received: by 2002:a17:90b:1c92:: with SMTP id oo18mr11865908pjb.56.1629328961377; Wed, 18 Aug 2021 16:22:41 -0700 (PDT) Received: from realwakka ([59.12.165.26]) by smtp.gmail.com with ESMTPSA id t20sm994870pgb.16.2021.08.18.16.22.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Aug 2021 16:22:41 -0700 (PDT) Date: Wed, 18 Aug 2021 23:22:32 +0000 From: Sidong Yang To: dsterba@suse.cz, linux-btrfs Subject: Re: [PATCH] btrfs: reflink: Assure length != 0 in btrfs_extent_same() Message-ID: <20210818232232.GA1987@realwakka> References: <20210818160815.1820-1-realwakka@gmail.com> <20210818222447.GX5047@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210818222447.GX5047@twin.jikos.cz> Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Aug 19, 2021 at 12:24:47AM +0200, David Sterba wrote: > On Wed, Aug 18, 2021 at 04:08:15PM +0000, Sidong Yang wrote: > > btrfs_extent_same() cannot be called with zero length. Because when > > length is zero, it would be filtered by condition in > > btrfs_remap_file_range(). But if this function is used in other case in > > future, it can make ret as uninitialized. > > Do you have a specific future in mind? Adding the assert won't hurt so > ok. No, sorry, I just want to make it safe. is there any way to better than adding assert? Would it better to initialize ret?