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 lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0BCCCC982FA for ; Tue, 22 Sep 2026 19:17:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x95zF-0007id-Oj; Tue, 22 Sep 2026 15:17:07 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x95yz-0007fe-VW for qemu-devel@nongnu.org; Tue, 22 Sep 2026 15:16:52 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x95yy-0001j3-IH for qemu-devel@nongnu.org; Tue, 22 Sep 2026 15:16:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1790104606; 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: in-reply-to:in-reply-to:references:references; bh=i9nKsLHcUYOkNmww3ns8XKnSnw+vXWYOFxQ9g6eT7B4=; b=UkByXW1WG/IXZ3Tb+2V/urmLMfV4ABW24J8e3069du3hSbuta7vraPicMVTm9/cHJ5d8Z7 R1NWAnRUZ6MKQhoPwBJwpd596obCCyrnW9fi5ljkJB1VDpHfNPaOfS/gcEQThp21nWdDiv xi82HDKP9LqiVzcEzTtjI4sIaOEpk44= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-683-CWtZmvhKOVatHtYF4OPcPA-1; Tue, 22 Sep 2026 15:16:42 -0400 X-MC-Unique: CWtZmvhKOVatHtYF4OPcPA-1 X-Mimecast-MFC-AGG-ID: CWtZmvhKOVatHtYF4OPcPA_1790104601 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AED20180062D; Tue, 22 Sep 2026 19:16:40 +0000 (UTC) Received: from localhost (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 470D441B; Tue, 22 Sep 2026 19:16:40 +0000 (UTC) Date: Tue, 22 Sep 2026 15:16:39 -0400 From: Stefan Hajnoczi To: Niklas Cassel Cc: Kevin Wolf , Hanna Reitz , Sam Li , Damien Le Moal , qemu-block@nongnu.org, qemu-devel@nongnu.org Subject: Re: [PATCH v6 12/15] block: remove BlockLimits.max_append_sectors Message-ID: <20260922191639.GF340123@fedora> References: <20260921142819.2916043-1-cassel@kernel.org> <20260921142819.2916043-13-cassel@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="sCaqiKDs+L+wOsj8" Content-Disposition: inline In-Reply-To: <20260921142819.2916043-13-cassel@kernel.org> X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --sCaqiKDs+L+wOsj8 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Sep 21, 2026 at 04:28:14PM +0200, Niklas Cassel wrote: > The field described the largest zone append that a backend accepts. It > had one writer and one reader, and neither is left. >=20 > file-posix filled it from the zone_append_max_bytes queue attribute, > which bounds REQ_OP_ZONE_APPEND, an operation it never issues: Linux has > no userspace interface for one, so raw_co_zone_append() substitutes the > write pointer of the zone for the offset and the request reaches the > host as a plain pwritev(). >=20 > The transfer limit does not apply either, no more than it does to an > ordinary write. This driver reports max_hw_transfer but never sets > BlockLimits.max_transfer, which is what bdrv_aligned_pwritev() splits > by, so a request of any size goes to the host kernel whole and is split > there: on a null_blk device whose zone_append_max_bytes is 130560, a > 16 MiB append completes and advances the write pointer by 16 MiB. That > is safe for a sequential zone, as Linux issues the fragments of a split > write in order, with zone write plugging since 6.10 and zone write > locking before that. >=20 > virtio-blk was the reader, and now takes what it reports to a guest from > a property instead. >=20 > Remove the field and the assignment that filled it. Keeping it would be > worse than not having it: a driver that set it, believing something > enforced it, would be silently ignored. >=20 > Signed-off-by: Niklas Cassel > --- > block/file-posix.c | 5 ----- > include/block/block_int-common.h | 3 --- > 2 files changed, 8 deletions(-) Reviewed-by: Stefan Hajnoczi --sCaqiKDs+L+wOsj8 Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmqy1BcACgkQnKSrs4Gr c8hwoAf8CrUQ9b9B6CitfPggqp4OEMlpSd/NFjACkJeTbyp1j4ahKjFOKmpgA3MX lGbc4XjWOT89tPMf8bGviy0mQ36uqDQEseZfjj8kx4zYWF/ChSEOGYpGkly2jW8H 5qDks2C1maqvielDwPCafQegO7F5nbILgdHt1IznSsgR0C74Lmb+TdAbuBUfuj0C q1SmS2JLsZPAChvKbMbck7l5k6R1vuZguXEU/0LjKHnyheV9TSNw6YxMdGm9YPdY qrpPy9sAV2QMu3tdfi2j3XLglGgs0OMeEpVj/WEbXEetX6xvT1+8RvNKWtkKFrSb 5xFQ2Smt+T50N7r+N3EQ4rnFedL4zQ== =+C5v -----END PGP SIGNATURE----- --sCaqiKDs+L+wOsj8--