From nobody Sun May 5 16:39:47 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1488310729006199.02659084778418; Tue, 28 Feb 2017 11:38:49 -0800 (PST) Received: from localhost ([::1]:36494 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cinbj-0002ZA-JT for importer@patchew.org; Tue, 28 Feb 2017 14:38:47 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53212) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cinWy-00081L-FY for qemu-devel@nongnu.org; Tue, 28 Feb 2017 14:33:56 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cinWv-0000Bm-AJ for qemu-devel@nongnu.org; Tue, 28 Feb 2017 14:33:52 -0500 Received: from mailhub.sw.ru ([195.214.232.25]:23137 helo=relay.sw.ru) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cinWu-00008l-VE for qemu-devel@nongnu.org; Tue, 28 Feb 2017 14:33:49 -0500 Received: from kvm.sw.ru (msk-vpn.virtuozzo.com [195.214.232.6]) by relay.sw.ru (8.13.4/8.13.4) with ESMTP id v1SJXe3b021480; Tue, 28 Feb 2017 22:33:41 +0300 (MSK) From: Vladimir Sementsov-Ogievskiy To: qemu-block@nongnu.org, qemu-devel@nongnu.org Date: Tue, 28 Feb 2017 22:33:40 +0300 Message-Id: <20170228193340.63980-1-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.11.1 X-detected-operating-system: by eggs.gnu.org: OpenBSD 3.x [fuzzy] X-Received-From: 195.214.232.25 Subject: [Qemu-devel] [PATCH v4] backup: allow target without .bdrv_get_info X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, vsementsov@virtuozzo.com, famz@redhat.com, jcody@redhat.com, mreitz@redhat.com, stefanha@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Currently backup to nbd target is broken, as nbd doesn't have .bdrv_get_info realization. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake --- v4: use error_report() add article v3: fix compilation (I feel like an idiot) adjust wording (Fam) =20 v2: add WARNING =3D=3D=3D Since commit commit 4c9bca7e39a6e07ad02c1dcde3478363344ec60b Author: John Snow Date: Thu Feb 25 15:58:30 2016 -0500 block/backup: avoid copying less than full target clusters backup to nbd target is broken, we have "Couldn't determine the cluster siz= e of the target image". Proposed NBD protocol extension - NBD_OPT_INFO should finally solve this pr= oblem. But until it is not realized, we need allow backup to nbd target due to bac= kward compatibility. Furthermore, is it entirely ok to disallow backup if bds lacks .bdrv_get_in= fo? Which behavior should be default: to fail backup or to use default cluster = size? block/backup.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/block/backup.c b/block/backup.c index ea38733849..ea160e9e82 100644 --- a/block/backup.c +++ b/block/backup.c @@ -24,6 +24,7 @@ #include "qemu/cutils.h" #include "sysemu/block-backend.h" #include "qemu/bitmap.h" +#include "qemu/error-report.h" =20 #define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16) #define SLICE_TIME 100000000ULL /* ns */ @@ -638,7 +639,16 @@ BlockJob *backup_job_create(const char *job_id, BlockD= riverState *bs, * backup cluster size is smaller than the target cluster size. Even f= or * targets with a backing file, try to avoid COW if possible. */ ret =3D bdrv_get_info(target, &bdi); - if (ret < 0 && !target->backing) { + if (ret =3D=3D -ENOTSUP) { + /* Cluster size is not defined */ + error_report("WARNING: The target block device doesn't provide " + "information about the block size and it doesn't have= a " + "backing file. The default block size of %u bytes is " + "used. If the actual block size of the target exceeds= " + "this default, the backup may be unusable", + BACKUP_CLUSTER_SIZE_DEFAULT); + job->cluster_size =3D BACKUP_CLUSTER_SIZE_DEFAULT; + } else if (ret < 0 && !target->backing) { error_setg_errno(errp, -ret, "Couldn't determine the cluster size of the target image, " "which has no backing file"); --=20 2.11.1