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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4D975C433F5 for ; Wed, 24 Nov 2021 07:12:30 +0000 (UTC) Received: from localhost ([::1]:48240 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mpmSD-0000Zq-45 for qemu-devel@archiver.kernel.org; Wed, 24 Nov 2021 02:12:29 -0500 Received: from eggs.gnu.org ([209.51.188.92]:59210) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mpm2E-0004cO-Ok for qemu-devel@nongnu.org; Wed, 24 Nov 2021 01:45:39 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:33551) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mpm2A-0004ve-JH for qemu-devel@nongnu.org; Wed, 24 Nov 2021 01:45:36 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1637736331; 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=zvcl9Zi/bafW66kB1cff1nQQJNzhFwaC9A3bzmRw8jM=; b=Qqz1qnq8mijmx6Noad6SZaVMmNEG3XhuOjv0NkN9JzlLgk3YePiEy9PD2YRF3sJvpg7t8m PM93DKFQu9PDadYeRsuuydeb3er8la8s7mW71YOGBXAeVRqmjVY9ijMCdm5qRBzsVnEVKe YIwUSKdqJdVI0+htJQexSn3ZfiQ3xsY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-166-6Ijlzuq0MveeitDdLf5KMA-1; Wed, 24 Nov 2021 01:45:29 -0500 X-MC-Unique: 6Ijlzuq0MveeitDdLf5KMA-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id AEAC9102CB73; Wed, 24 Nov 2021 06:45:28 +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 85F6160843; Wed, 24 Nov 2021 06:45:27 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Subject: [PATCH v5 09/31] block: introduce assert_bdrv_graph_writable Date: Wed, 24 Nov 2021 01:43:56 -0500 Message-Id: <20211124064418.3120601-10-eesposit@redhat.com> In-Reply-To: <20211124064418.3120601-1-eesposit@redhat.com> References: <20211124064418.3120601-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=170.10.133.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, 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: 2.1.29 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=20P=2E=20Berrang=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 under BQL and drain. BQL prevents from concurrent writings from the GS API, while drains protect from I/O. TODO: drains are missing in some functions using this assert. Therefore a proper assertion will fail. Because adding drains requires additional discussions, they will be added in future series. Signed-off-by: Emanuele Giuseppe Esposito --- include/block/block_int-global-state.h | 10 +++++++++- block.c | 4 ++++ block/io.c | 11 +++++++++++ 3 files changed, 24 insertions(+), 1 deletion(-) diff --git a/include/block/block_int-global-state.h b/include/block/block_int-global-state.h index a1b7d0579d..fa96e8b449 100644 --- a/include/block/block_int-global-state.h +++ b/include/block/block_int-global-state.h @@ -312,4 +312,12 @@ 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 running under both drain and BQL. + * The latter protects from concurrent writings + * from the GS API, while the former prevents concurrent reads + * from I/O. + */ +void assert_bdrv_graph_writable(BlockDriverState *bs); + +#endif /* BLOCK_INT_GLOBAL_STATE */ diff --git a/block.c b/block.c index 198ec636ff..522a273140 100644 --- a/block.c +++ b/block.c @@ -1416,6 +1416,7 @@ static void bdrv_child_cb_attach(BdrvChild *child) { BlockDriverState *bs = child->opaque; + assert_bdrv_graph_writable(bs); QLIST_INSERT_HEAD(&bs->children, child, next); if (child->role & BDRV_CHILD_COW) { @@ -1435,6 +1436,7 @@ static void bdrv_child_cb_detach(BdrvChild *child) bdrv_unapply_subtree_drain(child, bs); + assert_bdrv_graph_writable(bs); QLIST_REMOVE(child, next); } @@ -2818,6 +2820,7 @@ static void bdrv_replace_child_noperm(BdrvChild **childp, if (child->klass->detach) { child->klass->detach(child); } + assert_bdrv_graph_writable(old_bs); QLIST_REMOVE(child, next_parent); } @@ -2827,6 +2830,7 @@ static void bdrv_replace_child_noperm(BdrvChild **childp, } if (new_bs) { + assert_bdrv_graph_writable(new_bs); QLIST_INSERT_HEAD(&new_bs->parents, child, next_parent); /* diff --git a/block/io.c b/block/io.c index cb095deeec..3be08cad29 100644 --- a/block/io.c +++ b/block/io.c @@ -734,6 +734,17 @@ void bdrv_drain_all(void) bdrv_drain_all_end(); } +void assert_bdrv_graph_writable(BlockDriverState *bs) +{ + /* + * TODO: this function is incomplete. Because the users of this + * assert lack the necessary drains, check only for BQL. + * Once the necessary drains are added, + * assert also for qatomic_read(&bs->quiesce_counter) > 0 + */ + assert(qemu_in_main_thread()); +} + /** * Remove an active request from the tracked requests list * -- 2.27.0