From patchwork Wed Nov 16 13:48:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Emanuele Giuseppe Esposito X-Patchwork-Id: 13045234 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 2F352C4332F for ; Wed, 16 Nov 2022 13:52:27 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ovIn3-0000sI-Mj; Wed, 16 Nov 2022 08:49:21 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ovImx-0000mI-QJ for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:15 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ovImm-00082o-SG for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668606544; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=O674RGVxUBm8Idb7TTf4T44EFihJr3wsC24ssr01v7s=; b=YW07zA4bx7kM0qk1uhhYoVkXNPDD3uli1Ov8kFXnsPcLKnnipTtAtCtVdoHifUBRIKVr+N S8sWo/41SBsXIYrQaii5GM0CO+D877cr0gE67JCKcn1Z8pWr2w2+GyyLJEQRzqCsTkFwJg t3/HaOlnmRexFZvJP8ao3PBvyP1RUHs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-573-omFFKHu1NpmXtkh_LJXddg-1; Wed, 16 Nov 2022 08:48:57 -0500 X-MC-Unique: omFFKHu1NpmXtkh_LJXddg-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6BA90811E75; Wed, 16 Nov 2022 13:48:57 +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 1EBB44A9266; Wed, 16 Nov 2022 13:48:57 +0000 (UTC) From: Emanuele Giuseppe Esposito To: qemu-block@nongnu.org Cc: Kevin Wolf , Hanna Reitz , John Snow , Paolo Bonzini , Vladimir Sementsov-Ogievskiy , Stefan Hajnoczi , Fam Zheng , Eric Blake , Cleber Rosa , qemu-devel@nongnu.org, Emanuele Giuseppe Esposito Subject: [PATCH 15/20] block-gen: assert that {bdrv/blk}_co_flush is always called with graph rdlock taken Date: Wed, 16 Nov 2022 08:48:45 -0500 Message-Id: <20221116134850.3051419-16-eesposit@redhat.com> In-Reply-To: <20221116134850.3051419-1-eesposit@redhat.com> References: <20221116134850.3051419-1-eesposit@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eesposit@redhat.com; helo=us-smtp-delivery-124.mimecast.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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org This function, in addition to be called by a generated_co_wrapper, is also called by the blk_* API. The strategy is to always take the lock at the function called when the coroutine is created, to avoid recursive locking. Protecting bdrv_co_flush() implies that the following BlockDriver callbacks always called with graph rdlock taken: - bdrv_co_flush - bdrv_co_flush_to_os - bdrv_co_flush_to_disk Signed-off-by: Emanuele Giuseppe Esposito --- block/block-backend.c | 3 ++- block/io.c | 1 + include/block/block_int-common.h | 6 ++++++ 3 files changed, 9 insertions(+), 1 deletion(-) diff --git a/block/block-backend.c b/block/block-backend.c index 083ed6009e..d660772375 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1759,8 +1759,9 @@ int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset, /* To be called between exactly one pair of blk_inc/dec_in_flight() */ static int coroutine_fn blk_co_do_flush(BlockBackend *blk) { - blk_wait_while_drained(blk); IO_CODE(); + blk_wait_while_drained(blk); + GRAPH_RDLOCK_GUARD(); if (!blk_is_available(blk)) { return -ENOMEDIUM; diff --git a/block/io.c b/block/io.c index cfc201ef91..0bf3919939 100644 --- a/block/io.c +++ b/block/io.c @@ -2757,6 +2757,7 @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs) int ret = 0; IO_CODE(); + assert_bdrv_graph_readable(); bdrv_inc_in_flight(bs); if (!bdrv_is_inserted(bs) || bdrv_is_read_only(bs) || diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index 64c5bb64de..bab0521943 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -661,6 +661,8 @@ struct BlockDriver { * Flushes all data for all layers by calling bdrv_co_flush for underlying * layers, if needed. This function is needed for deterministic * synchronization of the flush finishing callback. + * + * Called with graph rdlock taken. */ int coroutine_fn (*bdrv_co_flush)(BlockDriverState *bs); @@ -671,6 +673,8 @@ struct BlockDriver { /* * Flushes all data that was already written to the OS all the way down to * the disk (for example file-posix.c calls fsync()). + * + * Called with graph rdlock taken. */ int coroutine_fn (*bdrv_co_flush_to_disk)(BlockDriverState *bs); @@ -678,6 +682,8 @@ struct BlockDriver { * Flushes all internal caches to the OS. The data may still sit in a * writeback cache of the host OS, but it will survive a crash of the qemu * process. + * + * Called with graph rdlock held. */ int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);