From patchwork Thu Feb 6 12:51:31 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 11368371 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E46D01398 for ; Thu, 6 Feb 2020 13:01:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BC671217BA for ; Thu, 6 Feb 2020 13:01:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NELOLgqH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC671217BA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:38416 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1izgmB-0006zm-UE for patchwork-qemu-devel@patchwork.kernel.org; Thu, 06 Feb 2020 08:00:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:57910) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1izgdk-00048Z-JX for qemu-devel@nongnu.org; Thu, 06 Feb 2020 07:52:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1izgdj-0002GD-Et for qemu-devel@nongnu.org; Thu, 06 Feb 2020 07:52:16 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:46281 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 1izgdj-0002Ef-AW for qemu-devel@nongnu.org; Thu, 06 Feb 2020 07:52:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1580993535; 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=mP+nNpAcdiBs92E8MUmJ6ArcZRiK8Dip4hFYun9uhac=; b=NELOLgqHjZf+01KlZEFRzwMXmngPPdpgY7ih1/tLQAPRaaci/VM83IOG3Z1WIFmFEJi5Mh kTgsUluKxMGHBArYYAcSj335Bln1Gk2x9/WW3wkQhxwLxD71ZId6tFPTfdHnrJkBPFH6TJ nRC3PQqJjaBnFSuqJx029rHgglN41y0= 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-186-XP2PixYYPNSTmR3nmI14FQ-1; Thu, 06 Feb 2020 07:52:08 -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 887981137841; Thu, 6 Feb 2020 12:52:07 +0000 (UTC) Received: from localhost (unknown [10.36.118.15]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2AFFB863A5; Thu, 6 Feb 2020 12:52:07 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 16/17] block/backup-top: fix failure path Date: Thu, 6 Feb 2020 13:51:31 +0100 Message-Id: <20200206125132.594625-17-mreitz@redhat.com> In-Reply-To: <20200206125132.594625-1-mreitz@redhat.com> References: <20200206125132.594625-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: XP2PixYYPNSTmR3nmI14FQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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: Kevin Wolf , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy We can't access top after call bdrv_backup_top_drop, as it is already freed at this time. Also, no needs to unref target child by hand, it will be unrefed on bdrv_close() automatically. So, just do bdrv_backup_top_drop if append succeed and one bdrv_unref otherwise. Note, that in !appended case bdrv_unref(top) moved into drained section on source. It doesn't really matter, but just for code simplicity. Fixes: 7df7868b96404 Cc: qemu-stable@nongnu.org # v4.2.0 Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Max Reitz Message-id: 20200121142802.21467-2-vsementsov@virtuozzo.com Signed-off-by: Max Reitz --- block/backup-top.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/block/backup-top.c b/block/backup-top.c index 9aed2eb4c0..fa78f3256d 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -190,6 +190,7 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, BlockDriverState *top = bdrv_new_open_driver(&bdrv_backup_top_filter, filter_node_name, BDRV_O_RDWR, errp); + bool appended = false; if (!top) { return NULL; @@ -212,8 +213,9 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, bdrv_append(top, source, &local_err); if (local_err) { error_prepend(&local_err, "Cannot append backup-top filter: "); - goto append_failed; + goto fail; } + appended = true; /* * bdrv_append() finished successfully, now we can require permissions @@ -224,14 +226,14 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, if (local_err) { error_prepend(&local_err, "Cannot set permissions for backup-top filter: "); - goto failed_after_append; + goto fail; } state->bcs = block_copy_state_new(top->backing, state->target, cluster_size, write_flags, &local_err); if (local_err) { error_prepend(&local_err, "Cannot create block-copy-state: "); - goto failed_after_append; + goto fail; } *bcs = state->bcs; @@ -239,14 +241,15 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source, return top; -failed_after_append: - state->active = false; - bdrv_backup_top_drop(top); +fail: + if (appended) { + state->active = false; + bdrv_backup_top_drop(top); + } else { + bdrv_unref(top); + } -append_failed: bdrv_drained_end(source); - bdrv_unref_child(top, state->target); - bdrv_unref(top); error_propagate(errp, local_err); return NULL;