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 X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E6D1C43603 for ; Wed, 11 Dec 2019 07:10:11 +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 5B4D020836 for ; Wed, 11 Dec 2019 07:10:11 +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="ZCQvR+0i" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B4D020836 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+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:39406 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iew8Q-0000ht-GP for qemu-devel@archiver.kernel.org; Wed, 11 Dec 2019 02:10:10 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:57485) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iew7k-0000Eg-FI for qemu-devel@nongnu.org; Wed, 11 Dec 2019 02:09:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iew7h-0000G5-Fv for qemu-devel@nongnu.org; Wed, 11 Dec 2019 02:09:26 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:35683) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iew7h-0000DH-8S for qemu-devel@nongnu.org; Wed, 11 Dec 2019 02:09:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576048164; 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:autocrypt:autocrypt; bh=/eFChM1uzr6GTD4nc0lLA3g3f5mNeVkqshrWOPNNsvA=; b=ZCQvR+0iOsfx4GMwQeUR3NVFFzrwgTo03M7h1Igub5MvnaS1rl0V62u2rc+s3UsG103pGK 45NZVR8IwopheJGf815v7r9SbjEQhlaJLHsyVdPK8nPdh8vW8FGYM2EiqQEXqLz4VnrpFl ZlfcjkvKshAMYN3wAeG7kvcs1gUz0hA= 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-9-mFuj1QC0Nji4bueo512GSg-1; Wed, 11 Dec 2019 02:09:18 -0500 X-MC-Unique: mFuj1QC0Nji4bueo512GSg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1EFF58024D6; Wed, 11 Dec 2019 07:09:17 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-116-167.ams2.redhat.com [10.36.116.167]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 752E5707A4; Wed, 11 Dec 2019 07:09:12 +0000 (UTC) Subject: Re: [PATCH for-4.2? v3 0/8] block: Fix resize (extending) of short overlays To: Kevin Wolf , qemu-block@nongnu.org References: <20191122160511.8377-1-kwolf@redhat.com> <20191210174644.GC7103@linux.fritz.box> From: Max Reitz Autocrypt: addr=mreitz@redhat.com; prefer-encrypt=mutual; keydata= mQENBFXOJlcBCADEyyhOTsoa/2ujoTRAJj4MKA21dkxxELVj3cuILpLTmtachWj7QW+TVG8U /PsMCFbpwsQR7oEy8eHHZwuGQsNpEtNC2G/L8Yka0BIBzv7dEgrPzIu+W3anZXQW4702+uES U29G8TP/NGfXRRHGlbBIH9KNUnOSUD2vRtpOLXkWsV5CN6vQFYgQfFvmp5ZpPeUe6xNplu8V mcTw8OSEDW/ZnxJc8TekCKZSpdzYoxfzjm7xGmZqB18VFwgJZlIibt1HE0EB4w5GsD7x5ekh awIe3RwoZgZDLQMdOitJ1tUc8aqaxvgA4tz6J6st8D8pS//m1gAoYJWGwwIVj1DjTYLtABEB AAG0HU1heCBSZWl0eiA8bXJlaXR6QHJlZGhhdC5jb20+iQFTBBMBCAA9AhsDBQkSzAMABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheABQJVzie5FRhoa3A6Ly9rZXlzLmdudXBnLm5ldAAKCRD0 B9sAYdXPQDcIB/9uNkbYEex1rHKz3mr12uxYMwLOOFY9fstP5aoVJQ1nWQVB6m2cfKGdcRe1 2/nFaHSNAzT0NnKz2MjhZVmcrpyd2Gp2QyISCfb1FbT82GMtXFj1wiHmPb3CixYmWGQUUh+I AvUqsevLA+WihgBUyaJq/vuDVM1/K9Un+w+Tz5vpeMidlIsTYhcsMhn0L9wlCjoucljvbDy/ 8C9L2DUdgi3XTa0ORKeflUhdL4gucWoAMrKX2nmPjBMKLgU7WLBc8AtV+84b9OWFML6NEyo4 4cP7cM/07VlJK53pqNg5cHtnWwjHcbpGkQvx6RUx6F1My3y52vM24rNUA3+ligVEgPYBuQEN BFXOJlcBCADAmcVUNTWT6yLWQHvxZ0o47KCP8OcLqD+67T0RCe6d0LP8GsWtrJdeDIQk+T+F xO7DolQPS6iQ6Ak2/lJaPX8L0BkEAiMuLCKFU6Bn3lFOkrQeKp3u05wCSV1iKnhg0UPji9V2 W5eNfy8F4ZQHpeGUGy+liGXlxqkeRVhLyevUqfU0WgNqAJpfhHSGpBgihUupmyUg7lfUPeRM DzAN1pIqoFuxnN+BRHdAecpsLcbR8sQddXmDg9BpSKozO/JyBmaS1RlquI8HERQoe6EynJhd 64aICHDfj61rp+/0jTIcevxIIAzW70IadoS/y3DVIkuhncgDBvGbF3aBtjrJVP+5ABEBAAGJ ASUEGAEIAA8FAlXOJlcCGwwFCRLMAwAACgkQ9AfbAGHVz0CbFwf9F/PXxQR9i4N0iipISYjU sxVdjJOM2TMut+ZZcQ6NSMvhZ0ogQxJ+iEQ5OjnIputKvPVd5U7WRh+4lF1lB/NQGrGZQ1ic alkj6ocscQyFwfib+xIe9w8TG1CVGkII7+TbS5pXHRxZH1niaRpoi/hYtgzkuOPp35jJyqT/ /ELbqQTDAWcqtJhzxKLE/ugcOMK520dJDeb6x2xVES+S5LXby0D4juZlvUj+1fwZu+7Io5+B bkhSVPb/QdOVTpnz7zWNyNw+OONo1aBUKkhq2UIByYXgORPFnbfMY7QWHcjpBVw9MgC4tGeF R4bv+1nAMMxKmb5VvQCExr0eFhJUAHAhVg== Message-ID: <019ced4d-04ea-6a3d-ec6b-bb0d5fdd37d6@redhat.com> Date: Wed, 11 Dec 2019 08:09:10 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20191210174644.GC7103@linux.fritz.box> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="VmFhrwo0xpjamylzFpVAwtZXnyCD2ehd0" X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: vsementsov@virtuozzo.com, qemu-devel@nongnu.org, stefanha@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --VmFhrwo0xpjamylzFpVAwtZXnyCD2ehd0 Content-Type: multipart/mixed; boundary="J00KcfWdHo8pqd6HeO9BHiGk8q04a5lZZ" --J00KcfWdHo8pqd6HeO9BHiGk8q04a5lZZ Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 10.12.19 18:46, Kevin Wolf wrote: > Am 22.11.2019 um 17:05 hat Kevin Wolf geschrieben: >> See patch 4 for the description of the bug fixed. >=20 > I'm applying patches 3 and 5-7 to the block branch because they make > sense on their own. >=20 > The real fix will need another approach because the error handling is > broken in this one: If zeroing out fails (either because of NO_FALLBACK > or because of some other I/O error), bdrv_co_truncate() will return > failure, but the image size has already been increased, with potentially > incorrect data in the new area. >=20 > To fix this, we need to make sure that zeros will be read before we > commit the new image size to the image file (e.g. qcow2 header) and to > bs->total_sectors. In other words, it must become the responsibility of > the block driver. >=20 > To this effect, I'm planning to introduce a PREALLOC_MODE_ZERO_INIT flag > that can be or'ed to the preallocation mode. This will fail by default > because it looks like just another unimplemented preallocation mode to > block drivers. It will be requested explicitly by commit jobs and > automatically added by bdrv_co_truncate() if the backing file would > become visible (like in this series, but now for all preallocation > modes). I'm planning to implement it for qcow2 and file-posix for now, > which should cover most interesting cases. >=20 > Does this make sense to you? Sounds good to me. Max --J00KcfWdHo8pqd6HeO9BHiGk8q04a5lZZ-- --VmFhrwo0xpjamylzFpVAwtZXnyCD2ehd0 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl3wlhYACgkQ9AfbAGHV z0CMsAgAmMlPkphGl3gyJC6zda7Og6l2UtNrhhFJj/bQ5k2+Ez7Ysobdf1R6zmC+ VH4TUdrD+8aeXxI6M+MKbr1Z7oZbvuLvsh9yek2i7Eu90v1ftrcuJzkrmNjhgW0q hERpc1nZOYtB1FlNkMDpw15RGKsXY8iW6AmeiFnEzqRITZc2UYFVe+UOadYlif4c cjSqEWYJAiuutBAp3zDwGiKhtMDTjnU7RK4jSnVolM6rNPEfAw2v+f8keIgOwWAA o8HAgn4FBgScmjQlJExwSKCDF9MlAU0ui6XHg8P4fBdxGMPBu14j1bTKaqEtHp3f CSBsDmxnU8K8yC7vCe1RA0xDcDPdQQ== =Lpop -----END PGP SIGNATURE----- --VmFhrwo0xpjamylzFpVAwtZXnyCD2ehd0--