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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 36606C282CE for ; Wed, 22 May 2019 17:05:41 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0A87221473 for ; Wed, 22 May 2019 17:05:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A87221473 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 ([127.0.0.1]:47968 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTUgO-0004F1-8Q for qemu-devel@archiver.kernel.org; Wed, 22 May 2019 13:05:40 -0400 Received: from eggs.gnu.org ([209.51.188.92]:40602) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTUf6-0003Uw-FO for qemu-devel@nongnu.org; Wed, 22 May 2019 13:04:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hTUf2-0007ZN-Bd for qemu-devel@nongnu.org; Wed, 22 May 2019 13:04:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35492) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hTUep-0007K9-DV; Wed, 22 May 2019 13:04:04 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D44280F91; Wed, 22 May 2019 17:03:56 +0000 (UTC) Received: from localhost (ovpn-204-123.brq.redhat.com [10.40.204.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3600E5D9C3; Wed, 22 May 2019 17:03:53 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 22 May 2019 19:03:44 +0200 Message-Id: <20190522170352.12020-1-mreitz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Wed, 22 May 2019 17:04:01 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 0/8] block: Ignore loosening perm restrictions failures 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: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi, This series is mainly a fix for https://bugzilla.redhat.com/show_bug.cgi?id=3D1703793. The problem described there is that mirroring to a gluster volume, then switching off the volume makes qemu crash. There are two problems here: (1) file-posix reopens the FD all the time because it thinks the FD it has is RDONLY. It actually isn=E2=80=99t after the first reopen, we = just forgot to change the internal flags. That=E2=80=99s what patch 1 is = for. (2) Even then, when mirror completes, it drops its write permission on the FD. This requires a reopen, which will fail if the volume is down. Mirror doesn=E2=80=99t expect that. Nobody ever expects that dropping permissions can fail, and rightfully so because that=E2=80=99= s what I think we have generally agreed on. Therefore, the block layer should hide this error. This is what the last two patches are for. The penultimate patch adds two assertions: bdrv_replace_child() (for the old BDS) and bdrv_inactivate_recurse() assume they only ever drop assertions. This is now substantiated by these new assertions. It turns out that this assumption was just plain wrong. Patches 3 to 5 make it right. v3: - Received no reply to my =E2=80=9CHm, warnings break 'make check', so ma= ybe we should just keep quiet if loosening restrictions fails?=E2=80=9D questi= on, so I assume silence means agreement. Changed patch 7 accordingly. - Added a test: The fact how make check kind-of-but-not-really broke showed a nice reproducer: Launching qemu with some file, then deleting that file, then quitting qemu. - Rebase =E2=80=9Cconflict=E2=80=9D in patch 6: The forward declaration o= f bdrv_get_cumulative_perm() is already in qemu thanks to commit 481e0eeef4f. git-backport-diff against v2: Key: [----] : patches are identical [####] : number of functional differences between upstream/downstream pat= ch [down] : patch is downstream-only The flags [FC] indicate (F)unctional and (C)ontextual differences, respec= tively 001/8:[----] [--] 'file-posix: Update open_flags in raw_set_perm()' 002/8:[----] [--] 'block: Add bdrv_child_refresh_perms()' 003/8:[----] [--] 'block/mirror: Fix child permissions' 004/8:[----] [--] 'block/commit: Drop bdrv_child_try_set_perm()' 005/8:[0018] [FC] 'block: Fix order in bdrv_replace_child()' ^^^^ Again confuses my v2 patch with 8aecf1d1bd250a, should be: [----] : patches are identical 006/8:[0002] [FC] 'block: Add *tighten_restrictions to *check*_perm()' 007/8:[0018] [FC] 'block: Ignore loosening perm restrictions failures' 008/8:[down] 'iotests: Test failure to loosen restrictions' Max Reitz (8): file-posix: Update open_flags in raw_set_perm() block: Add bdrv_child_refresh_perms() block/mirror: Fix child permissions block/commit: Drop bdrv_child_try_set_perm() block: Fix order in bdrv_replace_child() block: Add *tighten_restrictions to *check*_perm() block: Ignore loosening perm restrictions failures iotests: Test failure to loosen restrictions include/block/block_int.h | 15 ++++ block.c | 153 +++++++++++++++++++++++++++++++------ block/commit.c | 2 - block/file-posix.c | 4 + block/mirror.c | 32 +++++--- tests/qemu-iotests/182 | 21 +++++ tests/qemu-iotests/182.out | 6 ++ 7 files changed, 198 insertions(+), 35 deletions(-) --=20 2.21.0