From nobody Sat Feb 7 07:30:50 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1632241151915411.7098928795774; Tue, 21 Sep 2021 09:19:11 -0700 (PDT) Received: from localhost ([::1]:36294 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mSiUA-00009H-Sk for importer@patchew.org; Tue, 21 Sep 2021 12:19:10 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43890) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mSiSP-0006Tu-8l for qemu-devel@nongnu.org; Tue, 21 Sep 2021 12:17:21 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:25329) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mSiSN-0001vX-Qo for qemu-devel@nongnu.org; Tue, 21 Sep 2021 12:17:21 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-298-CRnai8WyOnKgHegpII-z5A-1; Tue, 21 Sep 2021 12:17:18 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5F7F083DD1B; Tue, 21 Sep 2021 16:17:17 +0000 (UTC) Received: from blue.redhat.com (ovpn-115-8.phx2.redhat.com [10.3.115.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5A1915C23A; Tue, 21 Sep 2021 16:17:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632241039; 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; bh=eUZareu40yc3LfoZKtmzupV/LoF0ScfTB+CIPfGwpao=; b=VQhO9Qk2OBAVDP9J9PKaC3x3L0WqcR++TxI0tu3ntyvw/ChkIXxchLZZARMyycZs0L5CmI NoFC4g3bMGXhPY77AIl3KrB23QeaStlfTRWDoV+PkK6p+MiQ/QacMrNOs5wPGceEj5C2pp dmiDCVW+fBKNbHE+5jMj+PE4zhWeveI= X-MC-Unique: CRnai8WyOnKgHegpII-z5A-1 From: Eric Blake To: qemu-devel@nongnu.org Subject: [PATCH] nbd/client: Request larger block status by default Date: Tue, 21 Sep 2021 11:17:03 -0500 Message-Id: <20210921161703.2682802-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.475, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , hreitz@redhat.com, vsementsov@virtuozzo.com, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1632241152450100003 Content-Type: text/plain; charset="utf-8" Now that commit 5a1cfd21 has clarified that a driver's block_status can report larger *pnum than in the original request, we can take advantage of that in the NBD driver. Rather that limiting our request to the server based on the maximum @bytes our caller mentioned, we instead ask for as much status as possible (the minimum of our 4G limit or the rest of the export); the server will still only give us one extent in its answer (because we are using NBD_CMD_FLAG_REQ_ONE), but now the block layer's caching of data areas can take advantage of cases where the server gives us a large answer to avoid the need for future NBD_CMD_BLOCK_STATUS calls. Signed-off-by: Eric Blake --- block/nbd.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index f6ff1c4fb472..7c4ec058b0aa 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -1479,10 +1479,15 @@ static int coroutine_fn nbd_client_co_block_status( BDRVNBDState *s =3D (BDRVNBDState *)bs->opaque; Error *local_err =3D NULL; + /* + * No need to limit our over-the-wire request to @bytes; rather, + * ask the server for as much as it can send in one go, and the + * block layer will then cap things. + */ NBDRequest request =3D { .type =3D NBD_CMD_BLOCK_STATUS, .from =3D offset, .len =3D MIN(QEMU_ALIGN_DOWN(INT_MAX, bs->bl.request_alignment), - MIN(bytes, s->info.size - offset)), + s->info.size - offset), .flags =3D NBD_CMD_FLAG_REQ_ONE, }; --=20 2.31.1