From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 5C0F2C54EBD for ; Thu, 12 Jan 2023 11:47:50 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pFw3F-0007Me-NM; Thu, 12 Jan 2023 06:47:21 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pFw3E-0007MH-R6 for qemu-devel@nongnu.org; Thu, 12 Jan 2023 06:47:20 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pFw3D-0008RS-HB for qemu-devel@nongnu.org; Thu, 12 Jan 2023 06:47:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1673524038; 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: in-reply-to:in-reply-to:references:references; bh=8nbZuOUZA1MpVypC8WS+XsPUquWy7tmpa1Tr7PrVo+c=; b=JYn+TTybgJHL9bQ0rV/0n1RA840En2KCG69lTk4SYmgU8hZuEnJRYPt3Uf5wXsf0214IJs gRIy2HTavmi1TblZnTu6MOA+Xo9XL5HPH4LwZ0jYf/Gtr6QDhHIOmBHy0bwtqv3KdRx8X4 7IOw7xX4bCVS2knQh2QDfvBzx+mj+Bc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-325-JFCv3V_jOryhAMwK9aBf2w-1; Thu, 12 Jan 2023 06:47:15 -0500 X-MC-Unique: JFCv3V_jOryhAMwK9aBf2w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 51C8185A588; Thu, 12 Jan 2023 11:47:15 +0000 (UTC) Received: from redhat.com (unknown [10.39.195.125]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 79AE34085720; Thu, 12 Jan 2023 11:47:14 +0000 (UTC) Date: Thu, 12 Jan 2023 12:47:13 +0100 From: Kevin Wolf To: Zhiyong Ye Cc: mreitz@redhat.com, qemu-block@nongnu.org, qemu-devel@nongnu.org Subject: Re: Questions about how block devices use snapshots Message-ID: References: <90855f8f-76ce-0a5f-3156-e69b157342c9@bytedance.com> <26114701-2d32-136d-ca44-01048c61842d@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <26114701-2d32-136d-ca44-01048c61842d@bytedance.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 11.01.2023 um 17:21 hat Zhiyong Ye geschrieben: > Hi Kevin, > > Can I ask again how base.img + diff.qcow2 can be re-merged into one image > via qemu-img or hmp command when modified.img is discarded? You can either use 'qemu-img commit' to copy all of the data from diff.qcow2 back into base.img (this is probably what you want), or 'qemu-img rebase' to copy all of the data from base.img into diff.qcow2. Kevin