From nobody Tue Dec 16 13:01:15 2025 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 1494514136272749.0796789797164; Thu, 11 May 2017 07:48:56 -0700 (PDT) Received: from localhost ([::1]:48596 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8pOf-000731-QG for importer@patchew.org; Thu, 11 May 2017 10:48:53 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36462) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d8pA8-0001p7-Qc for qemu-devel@nongnu.org; Thu, 11 May 2017 10:33:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d8pA7-00073e-US for qemu-devel@nongnu.org; Thu, 11 May 2017 10:33:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53688) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d8pA0-0006wK-GQ; Thu, 11 May 2017 10:33:44 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 78EC5A090E; Thu, 11 May 2017 14:33:43 +0000 (UTC) Received: from noname.str.redhat.com (dhcp-192-175.str.redhat.com [10.33.192.175]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7C0647A407; Thu, 11 May 2017 14:33:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 78EC5A090E Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=kwolf@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 78EC5A090E From: Kevin Wolf To: qemu-block@nongnu.org Date: Thu, 11 May 2017 16:32:21 +0200 Message-Id: <1494513181-7900-19-git-send-email-kwolf@redhat.com> In-Reply-To: <1494513181-7900-1-git-send-email-kwolf@redhat.com> References: <1494513181-7900-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 11 May 2017 14:33:43 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 18/58] block: Reuse bs as backing hd for drive-backup sync=none 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, qemu-devel@nongnu.org, stefanha@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" From: Fam Zheng Opening the backing image for the second time is bad, especially here when it is also in use as the active image as the source. The drive-backup job itself doesn't read from target->backing for COW, instead it gets data from the write notifier, so it's not a big problem. However, exporting the target to NBD etc. won't work, because of the likely stale metadata cache. Use BDRV_O_NO_BACKING in this case and manually set up the backing BdrvChild. Cc: qemu-stable@nongnu.org Signed-off-by: Fam Zheng Signed-off-by: Kevin Wolf --- blockdev.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/blockdev.c b/blockdev.c index 0b38c3d..0d3773b 100644 --- a/blockdev.c +++ b/blockdev.c @@ -3151,6 +3151,7 @@ static BlockJob *do_drive_backup(DriveBackup *backup,= BlockJobTxn *txn, Error *local_err =3D NULL; int flags; int64_t size; + bool set_backing_hd =3D false; =20 if (!backup->has_speed) { backup->speed =3D 0; @@ -3201,6 +3202,8 @@ static BlockJob *do_drive_backup(DriveBackup *backup,= BlockJobTxn *txn, } if (backup->sync =3D=3D MIRROR_SYNC_MODE_NONE) { source =3D bs; + flags |=3D BDRV_O_NO_BACKING; + set_backing_hd =3D true; } =20 size =3D bdrv_getlength(bs); @@ -3227,7 +3230,9 @@ static BlockJob *do_drive_backup(DriveBackup *backup,= BlockJobTxn *txn, } =20 if (backup->format) { - options =3D qdict_new(); + if (!options) { + options =3D qdict_new(); + } qdict_put_str(options, "driver", backup->format); } =20 @@ -3238,6 +3243,14 @@ static BlockJob *do_drive_backup(DriveBackup *backup= , BlockJobTxn *txn, =20 bdrv_set_aio_context(target_bs, aio_context); =20 + if (set_backing_hd) { + bdrv_set_backing_hd(target_bs, source, &local_err); + if (local_err) { + bdrv_unref(target_bs); + goto out; + } + } + if (backup->has_bitmap) { bmap =3D bdrv_find_dirty_bitmap(bs, backup->bitmap); if (!bmap) { --=20 1.8.3.1