From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS3215 2.6.0.0/16 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id 841551F4D7 for ; Fri, 6 May 2022 21:24:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1444416AbiEFV1V (ORCPT ); Fri, 6 May 2022 17:27:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45388 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1442687AbiEFV1S (ORCPT ); Fri, 6 May 2022 17:27:18 -0400 Received: from pb-smtp1.pobox.com (pb-smtp1.pobox.com [64.147.108.70]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B1CB6EC64 for ; Fri, 6 May 2022 14:23:34 -0700 (PDT) Received: from pb-smtp1.pobox.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 0D8D011AA65; Fri, 6 May 2022 17:23:31 -0400 (EDT) (envelope-from junio@pobox.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type:content-transfer-encoding; s=sasl; bh=Tw74FJ75GZUs j3rV4COR+2Qh1ovPNH2fW3Zfz4E45BQ=; b=NbICAS3o8SNO/gyo6S0jgFy8HkVx /SmQ2G1oGtiXXypIm1NdU37wVS3Mv2DBQpv8668aHoVPeEvKwyG4TT8dKelczYv7 kEUXs2LlfKKjDrWY5J/LB4EEAeiiEPUXDheCN6L6nivmS7QjpVJ8uI0a9kHYcvTz SZMbCKZT55nvbNk= Received: from pb-smtp1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 02F2111AA62; Fri, 6 May 2022 17:23:31 -0400 (EDT) (envelope-from junio@pobox.com) Received: from pobox.com (unknown [34.83.65.128]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp1.pobox.com (Postfix) with ESMTPSA id 5BA3D11AA61; Fri, 6 May 2022 17:23:30 -0400 (EDT) (envelope-from junio@pobox.com) From: Junio C Hamano To: Philip Oakley Cc: Jason Hatton , =?utf-8?Q?Ren=C3=A9?= Scharfe , "git@vger.kernel.org" Subject: Re: [PATCH] Prevent git from rehashing 4GBi files References: Date: Fri, 06 May 2022 14:23:29 -0700 In-Reply-To: (Philip Oakley's message of "Fri, 6 May 2022 22:17:35 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 X-Pobox-Relay-ID: C6A76BCE-CD82-11EC-A169-5E84C8D8090B-77302942!pb-smtp1.pobox.com Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Philip Oakley writes: >> This may treat non-zero multiple of 4GiB as "not racy", but has >> anybody double checked the concern R=C3=A9ne brought up earlier that a >> 4GiB file that was added and then got rewritten to 2GiB within the >> same second would suddenly start getting treated as not racy? > This is the pre-existing problem, that ~1in 2^31 size changes might not > get noticed for size change. The 0 byte / 4GiB change is an identical > issue, as is changing from 3 bytes to 4GiB+3 bytes, etc., so that's no > worse than before (well maybe twice as 'unlikely'). OK, it added one more case to 2^32-1 existing cases, I guess. >> The patch (the firnal version of it anyway) needs to be accompanied >> by a handful of test additions to tickle corner cases like that. > They'd be protected by the EXPENSIVE prerequisite I would assume. Oh, absolutely. Thanks for spelling that out.