From patchwork Tue Oct 5 14:31:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 12536941 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E397C433F5 for ; Tue, 5 Oct 2021 14:46:27 +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 BA14261371 for ; Tue, 5 Oct 2021 14:46:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org BA14261371 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:43582 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mXli5-0001e0-PK for qemu-devel@archiver.kernel.org; Tue, 05 Oct 2021 10:46:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:53292) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXlX3-0003Gi-IX for qemu-devel@nongnu.org; Tue, 05 Oct 2021 10:35:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:41631) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mXlX0-0004g8-Kk for qemu-devel@nongnu.org; Tue, 05 Oct 2021 10:35:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633444498; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ME81RfnCl/3WTd5GL32ef7DJwA2zOrVaUa7UEoJ5j9A=; b=b/Q4/EDKUcaEJEjRz/Nw96DunNTfHK7rzaRDOKNwk5zxzs3R19IfPfROr386vLYJCajqgt a1tK4MVgGIO2rMAiDq3QYipdjXAjDWvmG7uwq8cDMHgmK7v1voL6/UN3fk1Bk1cX4mrepM uOkuHIFsJPCuk7lbi24LCLiS9j2qeO4= 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-167-P8dUiySyNTe-hIOnVyn2-g-1; Tue, 05 Oct 2021 10:34:57 -0400 X-MC-Unique: P8dUiySyNTe-hIOnVyn2-g-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id CB58D802935; Tue, 5 Oct 2021 14:34:55 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id 979801002391; Tue, 5 Oct 2021 14:34:54 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [RFC PATCH v2 08/25] block: introduce assert_bdrv_graph_writable Date: Tue, 5 Oct 2021 10:31:58 -0400 Message-Id: <20211005143215.29500-9-eesposit@redhat.com> In-Reply-To: <20211005143215.29500-1-eesposit@redhat.com> References: <20211005143215.29500-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eesposit@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.066, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, 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 , Fam Zheng , Vladimir Sementsov-Ogievskiy , =?utf-8?q?Daniel_P?= =?utf-8?q?=2E_Berrang=C3=A9?= , Eduardo Habkost , Juan Quintela , qemu-devel@nongnu.org, John Snow , Emanuele Giuseppe Esposito , Richard Henderson , Markus Armbruster , "Dr. David Alan Gilbert" , Hanna Reitz , Stefan Hajnoczi , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" We want to be sure that the functions that write the child and parent list of a bs are either under BQL or drain. If this guarantee holds, then we can read the list also in the I/O APIs. Signed-off-by: Emanuele Giuseppe Esposito Reviewed-by: Paolo Bonzini --- block.c | 5 +++++ block/io.c | 5 +++++ include/block/block_int-global-state.h | 8 +++++++- 3 files changed, 17 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index b912f517a4..7d1eb847a4 100644 --- a/block.c +++ b/block.c @@ -2711,12 +2711,14 @@ static void bdrv_replace_child_noperm(BdrvChild *child, if (child->klass->detach) { child->klass->detach(child); } + assert_bdrv_graph_writable(old_bs); QLIST_REMOVE(child, next_parent); } child->bs = new_bs; if (new_bs) { + assert_bdrv_graph_writable(new_bs); QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); /* @@ -2917,6 +2919,7 @@ static int bdrv_attach_child_noperm(BlockDriverState *parent_bs, return ret; } + assert_bdrv_graph_writable(parent_bs); QLIST_INSERT_HEAD(&parent_bs->children, *child, next); /* * child is removed in bdrv_attach_child_common_abort(), so don't care to @@ -3117,6 +3120,7 @@ static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child, void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) { g_assert(qemu_in_main_thread()); + assert_bdrv_graph_writable(parent); if (child == NULL) { return; } @@ -4878,6 +4882,7 @@ static void bdrv_remove_filter_or_cow_child_abort(void *opaque) BdrvRemoveFilterOrCowChild *s = opaque; BlockDriverState *parent_bs = s->child->opaque; + assert_bdrv_graph_writable(parent_bs); QLIST_INSERT_HEAD(&parent_bs->children, s->child, next); if (s->is_backing) { parent_bs->backing = s->child; diff --git a/block/io.c b/block/io.c index 21dcc5d962..d184183b07 100644 --- a/block/io.c +++ b/block/io.c @@ -739,6 +739,11 @@ void bdrv_drain_all(void) bdrv_drain_all_end(); } +void assert_bdrv_graph_writable(BlockDriverState *bs) +{ + g_assert(qatomic_read(&bs->quiesce_counter) > 0 || qemu_in_main_thread()); +} + /** * Remove an active request from the tracked requests list * diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h index aad549cb85..a53ab146fc 100644 --- a/include/block/block_int-global-state.h +++ b/include/block/block_int-global-state.h @@ -343,4 +343,10 @@ void bdrv_remove_aio_context_notifier(BlockDriverState *bs, */ void bdrv_drain_all_end_quiesce(BlockDriverState *bs); -#endif /* BLOCK_INT_GLOBAL_STATE*/ +/** + * Make sure that the function is either running under + * drain, or under BQL. + */ +void assert_bdrv_graph_writable(BlockDriverState *bs); + +#endif /* BLOCK_INT_GLOBAL_STATE */