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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BC2E9EB64DA for ; Sun, 16 Jul 2023 09:02:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229776AbjGPJCk (ORCPT ); Sun, 16 Jul 2023 05:02:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229483AbjGPJCi (ORCPT ); Sun, 16 Jul 2023 05:02:38 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A1E2D1 for ; Sun, 16 Jul 2023 02:01:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1689498110; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Ior1LwIUvl6lmQWns59as31BxZ8x5tykCT3ciFG9/Go=; b=TESL7HAdkQBwdFMjAP9+zRQj8NB+KntykXCmlI0Cju6GqLePucZxRC7ibLmaVpdtc8hRck B8CojjeLe+zn5Ul9PmASuiQdKtgOvnwDi7UY1cnpEHPCZdA/Q2/14myQkJsgkU3i2LZ/w0 DLUsdDN8jiu7QcDENvad5wzjmE1RYx0= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-496-qvWt1G_kNOae1dZxR0v1hA-1; Sun, 16 Jul 2023 05:01:49 -0400 X-MC-Unique: qvWt1G_kNOae1dZxR0v1hA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B22AF29AA3B4; Sun, 16 Jul 2023 09:01:48 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.2.16.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 036E92166B2B; Sun, 16 Jul 2023 09:01:47 +0000 (UTC) From: Florian Weimer To: Goffredo Baroncelli Cc: Neal Gompa , linux-btrfs@vger.kernel.org Subject: Re: btrfs loses 32-bit application compatibility after a while References: <87cz0w1bd0.fsf@oldenburg.str.redhat.com> Date: Sun, 16 Jul 2023 11:01:46 +0200 In-Reply-To: (Goffredo Baroncelli's message of "Sat, 15 Jul 2023 11:30:15 +0200") Message-ID: <87edl85ix1.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org * Goffredo Baroncelli: > On 15/07/2023 11.09, Neal Gompa wrote: >> On Sat, Jul 15, 2023 at 4:32=E2=80=AFAM Goffredo Baroncelli wrote: >>> > [..] >> It was somewhat common for Fedora users. A number of Fedora 32-bit >> ARM >> variants used Btrfs until 32-bit ARM was discontinued in Fedora 37[1]. >> openSUSE still has 32-bit ARM and x86 support in Tumbleweed. >> This issue is also possible on 64-bit x86 systems where 32-bit x86 >> applications run on it. That's what this report is about. We're >> hitting it in Fedora because our 32-bit x86 builds in Fedora >> infrastructure run on 64-bit x86 environments and triggered this[2]. >>=20 > > From what you wrote, it is seems more "it is technically supported" but n= ot > big users. Otherwise I expected that a lot of bugs or complaints happened > when it was deprecated from 5.9 and removed in 5.11. I think that for most users, it will take some time (years?) until they hit this issue. The builders are a bit of a special case. This is something where telemetry really could help. > Despite that, I am curious about what could happen when a 32 bit > application tries to access a 64 bit inode: does the kernel return only > the lower part of the inode number ? How this is handled in > other FS: what happens when an fs hosts more than 2^32 files ? > Unlikely but this may happen. BTRFS makes this more easy to happen. The expectation is that the kernel interfaces return EOVERFLOW, the same error code that is used for file sizes that cannot be represented using the 32-bit interfaces. Thanks, Florian