From nobody Wed Apr 16 08:03:27 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 1528728126560835.9260385423097; Mon, 11 Jun 2018 07:42:06 -0700 (PDT) Received: from localhost ([::1]:49239 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSO1F-0008AP-NH for importer@patchew.org; Mon, 11 Jun 2018 10:42:05 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53205) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSNmY-0004iu-Bh for qemu-devel@nongnu.org; Mon, 11 Jun 2018 10:26:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fSNmW-0001qH-TN for qemu-devel@nongnu.org; Mon, 11 Jun 2018 10:26:54 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:35298 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 1fSNmT-0001o9-Hw; Mon, 11 Jun 2018 10:26:49 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 21B568011059; Mon, 11 Jun 2018 14:26:49 +0000 (UTC) Received: from localhost (unknown [10.40.205.155]) by smtp.corp.redhat.com (Postfix) with ESMTPS id BFE44100294B; Mon, 11 Jun 2018 14:26:48 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Mon, 11 Jun 2018 16:26:00 +0200 Message-Id: <20180611142611.6609-19-mreitz@redhat.com> In-Reply-To: <20180611142611.6609-1-mreitz@redhat.com> References: <20180611142611.6609-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 11 Jun 2018 14:26:49 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Mon, 11 Jun 2018 14:26:49 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.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] [PULL 18/29] qemu-img: Resolve relative backing paths in rebase 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 , Peter Maydell , 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, rebase interprets a relative path for the new backing image as follows: (1) Open the new backing image with the given relative path (thus relative = to qemu-img's working directory). (2) Write it directly into the overlay's backing path field (thus relative to the overlay). If the overlay is not in qemu-img's working directory, both will be different interpretations, which may either lead to an error somewhere (either rebase fails because it cannot open the new backing image, or your overlay becomes unusable because its backing path does not point to a file), or, even worse, it may result in your rebase being performed for a different backing file than what your overlay will point to after the rebase. Fix this by interpreting the target backing path as relative to the overlay, like qemu-img does everywhere else. Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=3D1569835 Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz Message-id: 20180509182002.8044-2-mreitz@redhat.com Reviewed-by: Eric Blake Signed-off-by: Max Reitz --- qemu-img.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/qemu-img.c b/qemu-img.c index b1c1e484d2..ebe1b866da 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3251,6 +3251,9 @@ static int img_rebase(int argc, char **argv) } =20 if (out_baseimg[0]) { + const char *overlay_filename; + char *out_real_path; + options =3D qdict_new(); if (out_basefmt) { qdict_put_str(options, "driver", out_basefmt); @@ -3259,8 +3262,26 @@ static int img_rebase(int argc, char **argv) qdict_put_bool(options, BDRV_OPT_FORCE_SHARE, true); } =20 - blk_new_backing =3D blk_new_open(out_baseimg, NULL, + overlay_filename =3D bs->exact_filename[0] ? bs->exact_filename + : bs->filename; + out_real_path =3D g_malloc(PATH_MAX); + + bdrv_get_full_backing_filename_from_filename(overlay_filename, + out_baseimg, + out_real_path, + PATH_MAX, + &local_err); + if (local_err) { + error_reportf_err(local_err, + "Could not resolve backing filename: "); + ret =3D -1; + g_free(out_real_path); + goto out; + } + + blk_new_backing =3D blk_new_open(out_real_path, NULL, options, src_flags, &local_err); + g_free(out_real_path); if (!blk_new_backing) { error_reportf_err(local_err, "Could not open new backing file '%s': ", --=20 2.17.1