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=-11.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 41333C433EC for ; Fri, 17 Jul 2020 11:06:25 +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 0A8A72070E for ; Fri, 17 Jul 2020 11:06:25 +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="OfA9rqYu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A8A72070E 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]:39720 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jwOC8-0001e7-Bn for qemu-devel@archiver.kernel.org; Fri, 17 Jul 2020 07:06:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47198) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jwO86-0008RG-2z for qemu-devel@nongnu.org; Fri, 17 Jul 2020 07:02:15 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:45254 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jwO83-0006DQ-3c for qemu-devel@nongnu.org; Fri, 17 Jul 2020 07:02:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594983729; 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=msIXDQmQBa7e+AO47OCzJjnKCCwte1EhI+lLS0Pt0ho=; b=OfA9rqYuOACAYbzLlnEvb8tz5PY0l1xcQS0gl2TNqdMU513p2eu+5QD+BXTVus+e4EnrdA Yp6qhf/+WD985A8mN5rJrDnuIHzEEF0x/eO47RWQF+AHlewMjRX8ccKic9G0jHUgj8A1KF PDSkCbtGp0Y/G8w9Bx9dtZqcFeG6SKI= 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-65-skcIYPJbMlGl5dtVH9JQDg-1; Fri, 17 Jul 2020 07:02:07 -0400 X-MC-Unique: skcIYPJbMlGl5dtVH9JQDg-1 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 2E156100CCC2; Fri, 17 Jul 2020 11:02:06 +0000 (UTC) Received: from dresden.str.redhat.com (ovpn-113-123.ams2.redhat.com [10.36.113.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EA05F75554; Fri, 17 Jul 2020 11:02:04 +0000 (UTC) Subject: Re: [PATCH for-5.1 v2 1/2] block: Require aligned image size to avoid assertion failure To: Kevin Wolf , qemu-block@nongnu.org References: <20200716142601.111237-1-kwolf@redhat.com> <20200716142601.111237-2-kwolf@redhat.com> 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: <7567943c-85e0-5c5b-b67e-3b915d5fa9de@redhat.com> Date: Fri, 17 Jul 2020 13:02:02 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200716142601.111237-2-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="PaMGyDdWu77a1ahFdcB7LzWxYWfd6YUJb" Received-SPF: pass client-ip=207.211.31.120; envelope-from=mreitz@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/17 03:33:51 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, 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=-1, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org 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) --PaMGyDdWu77a1ahFdcB7LzWxYWfd6YUJb Content-Type: multipart/mixed; boundary="8KzwD2FHzqiDUQLAdajYP7RKjcLKtlhmk" --8KzwD2FHzqiDUQLAdajYP7RKjcLKtlhmk Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 16.07.20 16:26, Kevin Wolf wrote: > Unaligned requests will automatically be aligned to bl.request_alignment > and we can't extend write requests to access space beyond the end of the > image without resizing the image, so if we have the WRITE permission, > but not the RESIZE one, it's required that the image size is aligned. >=20 > Failing to meet this requirement could cause assertion failures like > this if RESIZE permissions weren't requested: >=20 > qemu-img: block/io.c:1910: bdrv_co_write_req_prepare: Assertion `end_sect= or <=3D bs->total_sectors || child->perm & BLK_PERM_RESIZE' failed. >=20 > This was e.g. triggered by qemu-img converting to a target image with 4k > request alignment when the image was only aligned to 512 bytes, but not > to 4k. >=20 > Turn this into a graceful error in bdrv_check_perm() so that WRITE > without RESIZE can only be taken if the image size is aligned. If a user > holds both permissions and drops only RESIZE, the function will return > an error, but bdrv_child_try_set_perm() will ignore the failure silently > if permissions are only requested to be relaxed and just keep both > permissions while returning success. >=20 > Signed-off-by: Kevin Wolf > --- > block.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) >=20 > diff --git a/block.c b/block.c > index 35a372df57..6371928edb 100644 > --- a/block.c > +++ b/block.c > @@ -2025,6 +2025,22 @@ static int bdrv_check_perm(BlockDriverState *bs, B= lockReopenQueue *q, > return -EPERM; > } > =20 > + /* > + * Unaligned requests will automatically be aligned to bl.request_al= ignment > + * and without RESIZE we can't extend requests to write to space bey= ond the > + * end of the image, so it's required that the image size is aligned= . > + */ > + if ((cumulative_perms & BLK_PERM_WRITE) && What about WRITE_UNCHANGED? I think this would only matter with nodes that can have backing files (i.e., qcow2 in practice) because WRITE_UNCHANGED is only used by COR and block jobs doing something with a backing chain, so it shouldn=E2=80=99t matter in practice, but, well. So, either way: Reviewed-by: Max Reitz > + !(cumulative_perms & BLK_PERM_RESIZE)) > + { > + if ((bs->total_sectors * BDRV_SECTOR_SIZE) % bs->bl.request_alig= nment) { > + error_setg(errp, "Cannot get 'write' permission without 'res= ize': " > + "Image size is not a multiple of request " > + "alignment"); > + return -EPERM; > + } > + } > + > /* Check this node */ > if (!drv) { > return 0; >=20 --8KzwD2FHzqiDUQLAdajYP7RKjcLKtlhmk-- --PaMGyDdWu77a1ahFdcB7LzWxYWfd6YUJb Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEkb62CjDbPohX0Rgp9AfbAGHVz0AFAl8RhSoACgkQ9AfbAGHV z0BEIwf+PggU6yozH+kvTuiow4vI5K/P1j2RDzfuxrsmXCQHGSBglMCip7d1st1x u8iAJUCLakKiqu8gi7eUBLlntj1kAy0gGda8vnlhgE697SCYnXK7wCxtbAJvxhLz 4crEplasTQhBGXgSoVTjyRsVfJg3GAFzouUqmo+Pm6a2DbXTJCMVuEr1+/dp4cWt rC9cK6VL+mDnOMaMR3LtSowsUwkoRAW0rD6uwFy9mlKbZWkSUAuXfeL7OYpfOQ6e 62hrPIR+YJafcudL1a/PEdwwbkmiNk1w+JHITrA4Away5HdUPs1OeFNMsuDP1kR6 GxkYk4CQaq2zI3nBJJTef/OtJq/meQ== =eR4g -----END PGP SIGNATURE----- --PaMGyDdWu77a1ahFdcB7LzWxYWfd6YUJb--