From patchwork Fri Jan 15 13:02:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 1426972 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=igalia.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=igalia.com header.i=@igalia.com header.a=rsa-sha256 header.s=20170329 header.b=AHPkMLkh; dkim-atps=neutral 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 ozlabs.org (Postfix) with ESMTPS id 4DHLwR09QRz9vGB for ; Sat, 16 Jan 2021 00:03:49 +1100 (AEDT) Received: from localhost ([::1]:41286 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l0OlW-00024u-0U for incoming@patchwork.ozlabs.org; Fri, 15 Jan 2021 08:03:46 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:35730) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l0Ol8-00022m-Q7; Fri, 15 Jan 2021 08:03:22 -0500 Received: from fanzine.igalia.com ([178.60.130.6]:44635) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1l0Ol3-0003wA-Sr; Fri, 15 Jan 2021 08:03:22 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=f8QA3U6Gnw8hWYP3Fzo72aiMuFKL6DyIS/zDdgwS/E4=; b=AHPkMLkh5C7zLTGl323vm92LMfDZW+mwkoJyYQfYPk0qbhbs/MvpMjUGN7tKDyhw/0a2oqYmtpX1S8lpo7c8nG06S4TTO0l6ctfViV972TT3ErxsFslQtWggxDwumzDOYHO4QT/9S8JbOx4EHrzRK03jl2HFoSFnELH9VtYl9dNibfZgRBkki1evSdPNn1g9xdlBq/NZ1WAaUFq4V1SC1kESfNTr6rqv3qKaj0Jf4L3KIeMxERJg0zIvh1fTkqFNzZ7s8RVDW8aBX9YxbVMetmP6TisGcfXf57bSn0sJQaLMg28MEm/7e4F51wMJTAbeC+7af0luW2qwTR+WH0Hq3g==; Received: from [213.94.31.64] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1l0Okg-0007Wc-NT; Fri, 15 Jan 2021 14:02:54 +0100 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1l0OkT-0003fm-RU; Fri, 15 Jan 2021 14:02:41 +0100 From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [RFC PATCH 1/2] block: Allow changing bs->file on reopen Date: Fri, 15 Jan 2021 14:02:37 +0100 Message-Id: <1a9b457d93c0732e8e4785a0cc4b5f3b935f2cf6.1610715661.git.berto@igalia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=178.60.130.6; envelope-from=berto@igalia.com; helo=fanzine.igalia.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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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: Kevin Wolf , Vladimir Sementsov-Ogievskiy , Alberto Garcia , qemu-block@nongnu.org, Kashyap Chamarthy , Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" When the x-blockdev-reopen was added it allowed reconfiguring the graph by replacing backing files, but changing the 'file' option was forbidden. Because of this restriction some operations are not possible, notably inserting and removing block filters. This patch adds support for replacing the 'file' option. This is similar to replacing the backing file and the user is likewise responsible for the correctness of the resulting graph, otherwise this can lead to data corruption. Signed-off-by: Alberto Garcia --- include/block/block.h | 1 + block.c | 61 ++++++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/245 | 7 ++--- 3 files changed, 66 insertions(+), 3 deletions(-) diff --git a/include/block/block.h b/include/block/block.h index 82271d9ccd..6dd687a69e 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -196,6 +196,7 @@ typedef struct BDRVReopenState { bool backing_missing; bool replace_backing_bs; /* new_backing_bs is ignored if this is false */ BlockDriverState *old_backing_bs; /* keep pointer for permissions update */ + BlockDriverState *old_file_bs; /* keep pointer for permissions update */ uint64_t perm, shared_perm; QDict *options; QDict *explicit_options; diff --git a/block.c b/block.c index 576b145cbf..114788e58e 100644 --- a/block.c +++ b/block.c @@ -3978,6 +3978,10 @@ int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp) refresh_list = bdrv_topological_dfs(refresh_list, found, state->old_backing_bs); } + if (state->old_file_bs) { + refresh_list = bdrv_topological_dfs(refresh_list, found, + state->old_file_bs); + } } ret = bdrv_list_refresh_perms(refresh_list, bs_queue, &tran, errp); @@ -4196,6 +4200,57 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, return 0; } +static int bdrv_reopen_parse_file(BDRVReopenState *reopen_state, + GSList **tran, + Error **errp) +{ + BlockDriverState *bs = reopen_state->bs; + BlockDriverState *new_file_bs; + QObject *value; + const char *str; + + value = qdict_get(reopen_state->options, "file"); + if (value == NULL) { + return 0; + } + + /* The 'file' option only allows strings */ + assert(qobject_type(value) == QTYPE_QSTRING); + + str = qobject_get_try_str(value); + new_file_bs = bdrv_lookup_bs(NULL, str, errp); + if (new_file_bs == NULL) { + return -EINVAL; + } else if (bdrv_recurse_has_child(new_file_bs, bs)) { + error_setg(errp, "Making '%s' a file of '%s' " + "would create a cycle", str, bs->node_name); + return -EINVAL; + } + + assert(bs->file && bs->file->bs); + + /* If 'file' points to the current child then there's nothing to do */ + if (bs->file->bs == new_file_bs) { + return 0; + } + + /* Check AioContext compatibility */ + if (!bdrv_reopen_can_attach(bs, bs->file, new_file_bs, errp)) { + return -EINVAL; + } + + /* At the moment only backing links are frozen */ + assert(!bs->file->frozen); + + /* Store the old file bs because we'll need to refresh its permissions */ + reopen_state->old_file_bs = bs->file->bs; + + /* And finally replace the child */ + bdrv_replace_child(bs->file, new_file_bs, tran); + + return 0; +} + /* * Prepares a BlockDriverState for reopen. All changes are staged in the * 'opaque' field of the BDRVReopenState, which is used and allocated by @@ -4347,6 +4402,12 @@ static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, } qdict_del(reopen_state->options, "backing"); + ret = bdrv_reopen_parse_file(reopen_state, set_backings_tran, errp); + if (ret < 0) { + goto error; + } + qdict_del(reopen_state->options, "file"); + /* Options that are not handled are only okay if they are unchanged * compared to the old state. It is expected that some options are only * used for the initial open, but not reopen (e.g. filename) */ diff --git a/tests/qemu-iotests/245 b/tests/qemu-iotests/245 index e60c8326d3..f9d68b3958 100755 --- a/tests/qemu-iotests/245 +++ b/tests/qemu-iotests/245 @@ -145,8 +145,8 @@ class TestBlockdevReopen(iotests.QMPTestCase): self.reopen(opts, {'driver': 'raw'}, "Cannot change the option 'driver'") self.reopen(opts, {'driver': ''}, "Invalid parameter ''") self.reopen(opts, {'driver': None}, "Invalid parameter type for 'driver', expected: string") - self.reopen(opts, {'file': 'not-found'}, "Cannot change the option 'file'") - self.reopen(opts, {'file': ''}, "Cannot change the option 'file'") + self.reopen(opts, {'file': 'not-found'}, "Cannot find device= nor node_name=not-found") + self.reopen(opts, {'file': ''}, "Cannot find device= nor node_name=") self.reopen(opts, {'file': None}, "Invalid parameter type for 'file', expected: BlockdevRef") self.reopen(opts, {'file.node-name': 'newname'}, "Cannot change the option 'node-name'") self.reopen(opts, {'file.driver': 'host_device'}, "Cannot change the option 'driver'") @@ -454,7 +454,8 @@ class TestBlockdevReopen(iotests.QMPTestCase): # More illegal operations self.reopen(opts[2], {'backing': 'hd1'}, "Making 'hd1' a backing file of 'hd2' would create a cycle") - self.reopen(opts[2], {'file': 'hd0-file'}, "Cannot change the option 'file'") + self.reopen(opts[2], {'file': 'hd0-file'}, + "Conflicts with use by hd2 as 'file', which does not allow 'write, resize' on hd0-file") result = self.vm.qmp('blockdev-del', conv_keys = True, node_name = 'hd2') self.assert_qmp(result, 'error/class', 'GenericError')