From nobody Tue Nov 4 23:49:21 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.zohomail.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; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1531480747390844.1199150886503; Fri, 13 Jul 2018 04:19:07 -0700 (PDT) Received: from localhost ([::1]:36542 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fdw6M-0000TE-8m for importer@patchew.org; Fri, 13 Jul 2018 07:19:06 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43862) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fdw1y-0005lV-4n for qemu-devel@nongnu.org; Fri, 13 Jul 2018 07:14:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fdw1x-0002cU-Ag for qemu-devel@nongnu.org; Fri, 13 Jul 2018 07:14:34 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:35898 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fdw1t-0002a4-4i; Fri, 13 Jul 2018 07:14:29 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C5FF07DAC8; Fri, 13 Jul 2018 11:14:28 +0000 (UTC) Received: from localhost (ovpn-117-56.ams2.redhat.com [10.36.117.56]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 79F621C722; Fri, 13 Jul 2018 11:14:28 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Fri, 13 Jul 2018 13:14:22 +0200 Message-Id: <20180713111424.23670-2-mreitz@redhat.com> In-Reply-To: <20180713111424.23670-1-mreitz@redhat.com> References: <20180713111424.23670-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 13 Jul 2018 11:14:28 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Fri, 13 Jul 2018 11:14:28 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'mreitz@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH 1/3] qemu-img: Allow rebase with no input base 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: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz 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, you cannot add a backing file to an image when it currently has none. It is really simple to allow this, though (effectively by setting old_backing_size to 0), so this patch does just that. Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- qemu-img.c | 61 ++++++++++++++++++++++++++++++------------------------ 1 file changed, 34 insertions(+), 27 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 9b7506b8ae..dd684d8bf0 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3280,26 +3280,30 @@ static int img_rebase(int argc, char **argv) char backing_name[PATH_MAX]; QDict *options =3D NULL; =20 - if (bs->backing_format[0] !=3D '\0') { - options =3D qdict_new(); - qdict_put_str(options, "driver", bs->backing_format); - } - - if (force_share) { - if (!options) { + if (bs->backing) { + if (bs->backing_format[0] !=3D '\0') { options =3D qdict_new(); + qdict_put_str(options, "driver", bs->backing_format); } - qdict_put_bool(options, BDRV_OPT_FORCE_SHARE, true); - } - bdrv_get_backing_filename(bs, backing_name, sizeof(backing_name)); - blk_old_backing =3D blk_new_open(backing_name, NULL, - options, src_flags, &local_err); - if (!blk_old_backing) { - error_reportf_err(local_err, - "Could not open old backing file '%s': ", - backing_name); - ret =3D -1; - goto out; + + if (force_share) { + if (!options) { + options =3D qdict_new(); + } + qdict_put_bool(options, BDRV_OPT_FORCE_SHARE, true); + } + bdrv_get_backing_filename(bs, backing_name, sizeof(backing_nam= e)); + blk_old_backing =3D blk_new_open(backing_name, NULL, + options, src_flags, &local_err); + if (!blk_old_backing) { + error_reportf_err(local_err, + "Could not open old backing file '%s': ", + backing_name); + ret =3D -1; + goto out; + } + } else { + blk_old_backing =3D NULL; } =20 if (out_baseimg[0]) { @@ -3355,7 +3359,7 @@ static int img_rebase(int argc, char **argv) */ if (!unsafe) { int64_t size; - int64_t old_backing_size; + int64_t old_backing_size =3D 0; int64_t new_backing_size =3D 0; uint64_t offset; int64_t n; @@ -3371,15 +3375,18 @@ static int img_rebase(int argc, char **argv) ret =3D -1; goto out; } - old_backing_size =3D blk_getlength(blk_old_backing); - if (old_backing_size < 0) { - char backing_name[PATH_MAX]; + if (blk_old_backing) { + old_backing_size =3D blk_getlength(blk_old_backing); + if (old_backing_size < 0) { + char backing_name[PATH_MAX]; =20 - bdrv_get_backing_filename(bs, backing_name, sizeof(backing_nam= e)); - error_report("Could not get size of '%s': %s", - backing_name, strerror(-old_backing_size)); - ret =3D -1; - goto out; + bdrv_get_backing_filename(bs, backing_name, + sizeof(backing_name)); + error_report("Could not get size of '%s': %s", + backing_name, strerror(-old_backing_size)); + ret =3D -1; + goto out; + } } if (blk_new_backing) { new_backing_size =3D blk_getlength(blk_new_backing); --=20 2.17.1