From nobody Sun Oct 5 21:17:18 2025 Delivered-To: importer@patchew.org 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; 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 1580493197522199.55903083305475; Fri, 31 Jan 2020 09:53:17 -0800 (PST) Received: from localhost ([::1]:57334 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ixaTk-0008FB-D8 for importer@patchew.org; Fri, 31 Jan 2020 12:53:16 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:41567) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ixaLl-0003CB-78 for qemu-devel@nongnu.org; Fri, 31 Jan 2020 12:45:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ixaLk-0004iP-0O for qemu-devel@nongnu.org; Fri, 31 Jan 2020 12:45:01 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:34232 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ixaLj-0004ha-T9 for qemu-devel@nongnu.org; Fri, 31 Jan 2020 12:44:59 -0500 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-306-9WEUHAjVO7OdEaS2C4nYeA-1; Fri, 31 Jan 2020 12:44:55 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AFB998F4964; Fri, 31 Jan 2020 17:44:54 +0000 (UTC) Received: from blue.redhat.com (ovpn-116-181.phx2.redhat.com [10.3.116.181]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2835C7FB60; Fri, 31 Jan 2020 17:44:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580492699; 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=Jf6rrmMMkG7rUq9+VULR4sD8iT5fg6b7OJ1gXa5pIec=; b=Gk5b5oP4N4bFG43EDlIrhGL6hAM4w6gK9nwiAMMqIS9u/YmpD8dalMVDOvT9EGTc/v6Dk6 uwOHre1290MBb1+pXLMgFNYWpSvnpwKz+B+HKiA1h/kY/WdgqLg/D6stdaOp+mwJ6MgZrL OAMoEbDLnSUv7rpl5zmyZLM+ECSCydo= From: Eric Blake To: qemu-devel@nongnu.org Subject: [PATCH 12/17] gluster: Support BDRV_ZERO_OPEN Date: Fri, 31 Jan 2020 11:44:31 -0600 Message-Id: <20200131174436.2961874-13-eblake@redhat.com> In-Reply-To: <20200131174436.2961874-1-eblake@redhat.com> References: <20200131174436.2961874-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: 9WEUHAjVO7OdEaS2C4nYeA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 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: david.edmondson@oracle.com, Kevin Wolf , "open list:GLUSTER" , qemu-block@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" Since gluster already copies file-posix for lseek usage in block status, it also makes sense to copy it for learning if the image currently reads as all zeroes. Signed-off-by: Eric Blake --- block/gluster.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/block/gluster.c b/block/gluster.c index 9d952c70981b..0417a86547c8 100644 --- a/block/gluster.c +++ b/block/gluster.c @@ -1464,6 +1464,22 @@ exit: return -ENOTSUP; } +static int qemu_gluster_known_zeroes(BlockDriverState *bs) +{ + /* + * GlusterFS volume could be backed by a block device, with no way + * to query if regions added by creation or truncation will read + * as zeroes. However, we can use lseek(SEEK_DATA) to check if + * contents currently read as zero. + */ + off_t data, hole; + + if (find_allocation(bs, 0, &data, &hole) =3D=3D -ENXIO) { + return BDRV_ZERO_OPEN; + } + return 0; +} + /* * Returns the allocation status of the specified offset. * @@ -1561,6 +1577,7 @@ static BlockDriver bdrv_gluster =3D { .bdrv_co_readv =3D qemu_gluster_co_readv, .bdrv_co_writev =3D qemu_gluster_co_writev, .bdrv_co_flush_to_disk =3D qemu_gluster_co_flush_to_disk, + .bdrv_known_zeroes =3D qemu_gluster_known_zeroes, #ifdef CONFIG_GLUSTERFS_DISCARD .bdrv_co_pdiscard =3D qemu_gluster_co_pdiscard, #endif @@ -1591,6 +1608,7 @@ static BlockDriver bdrv_gluster_tcp =3D { .bdrv_co_readv =3D qemu_gluster_co_readv, .bdrv_co_writev =3D qemu_gluster_co_writev, .bdrv_co_flush_to_disk =3D qemu_gluster_co_flush_to_disk, + .bdrv_known_zeroes =3D qemu_gluster_known_zeroes, #ifdef CONFIG_GLUSTERFS_DISCARD .bdrv_co_pdiscard =3D qemu_gluster_co_pdiscard, #endif @@ -1621,6 +1639,7 @@ static BlockDriver bdrv_gluster_unix =3D { .bdrv_co_readv =3D qemu_gluster_co_readv, .bdrv_co_writev =3D qemu_gluster_co_writev, .bdrv_co_flush_to_disk =3D qemu_gluster_co_flush_to_disk, + .bdrv_known_zeroes =3D qemu_gluster_known_zeroes, #ifdef CONFIG_GLUSTERFS_DISCARD .bdrv_co_pdiscard =3D qemu_gluster_co_pdiscard, #endif @@ -1657,6 +1676,7 @@ static BlockDriver bdrv_gluster_rdma =3D { .bdrv_co_readv =3D qemu_gluster_co_readv, .bdrv_co_writev =3D qemu_gluster_co_writev, .bdrv_co_flush_to_disk =3D qemu_gluster_co_flush_to_disk, + .bdrv_known_zeroes =3D qemu_gluster_known_zeroes, #ifdef CONFIG_GLUSTERFS_DISCARD .bdrv_co_pdiscard =3D qemu_gluster_co_pdiscard, #endif --=20 2.24.1