From nobody Mon Apr 29 14:59:34 2024 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.zoho.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; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1491561224298901.2118830093125; Fri, 7 Apr 2017 03:33:44 -0700 (PDT) Received: from localhost ([::1]:49956 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwRD4-00038y-P6 for importer@patchew.org; Fri, 07 Apr 2017 06:33:42 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49910) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cwRCK-0002og-Bk for qemu-devel@nongnu.org; Fri, 07 Apr 2017 06:32:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cwRCJ-0003q7-F6 for qemu-devel@nongnu.org; Fri, 07 Apr 2017 06:32:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49400) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cwRCE-0003lP-Sh; Fri, 07 Apr 2017 06:32:50 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id EA0EA81F03; Fri, 7 Apr 2017 10:32:49 +0000 (UTC) Received: from noname.redhat.com (ovpn-117-140.ams2.redhat.com [10.36.117.140]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9DE07AC171; Fri, 7 Apr 2017 10:32:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com EA0EA81F03 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=kwolf@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com EA0EA81F03 From: Kevin Wolf To: qemu-block@nongnu.org Date: Fri, 7 Apr 2017 12:32:45 +0200 Message-Id: <1491561165-12415-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 07 Apr 2017 10:32:50 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH for-2.9] block: Don't check permissions for copy on read 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: kwolf@redhat.com, qemu-devel@nongnu.org, rjones@redhat.com, mreitz@redhat.com 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" The assertion is currently failing. We can't require callers to have write permissions when all they are doing is a read, so comment it out. Add a FIXME comment in the code so that the check is re-enabled when copy on read is refactored into its own filter driver. Reported-by: Richard W.M. Jones Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake Reviewed-by: Max Reitz --- block/io.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/block/io.c b/block/io.c index 2709a70..7321dda 100644 --- a/block/io.c +++ b/block/io.c @@ -945,7 +945,14 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvC= hild *child, size_t skip_bytes; int ret; =20 - assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); + /* FIXME We cannot require callers to have write permissions when all = they + * are doing is a read request. If we did things right, write permissi= ons + * would be obtained anyway, but internally by the copy-on-read code. = As + * long as it is implemented here rather than in a separat filter driv= er, + * the copy-on-read code doesn't have its own BdrvChild, however, for = which + * it could request permissions. Therefore we have to bypass the permi= ssion + * system for the moment. */ + // assert(child->perm & (BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE)); =20 /* Cover entire cluster so no additional backing file I/O is required = when * allocating cluster in the image file. --=20 1.8.3.1