From patchwork Fri Oct 27 15:53:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13455671 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1qwPAF-0004EH-GN for mharc-qemu-devel@gnu.org; Fri, 27 Oct 2023 11:54:23 -0400 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 1qwP9w-0003Z7-Qn for qemu-devel@nongnu.org; Fri, 27 Oct 2023 11:54:05 -0400 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 1qwP9v-0002l6-5K for qemu-devel@nongnu.org; Fri, 27 Oct 2023 11:54:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698422042; 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=SFa/ALYwlV6IJEf3ksTaj1ipsWNeMg/BP/QgPQkKH5Q=; b=F1BFBWm8I5J/+5OGrQD8Pmiqirca87T+6egB3LP7ODbIXvgOV1Sj9dtwHKoJ/aKJ39/YoV 6oYL7gmPvhjmXzRkktI3bnRIhNZrzVZTatQLHHfZvpIs2JpWmKS7qSa/lOBHw5P+dsJryf UNmA4Fifop8rSPc2vy1A0PMZqmzdmGU= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-221-oz_26MgXMameJNtmDODE2g-1; Fri, 27 Oct 2023 11:54:00 -0400 X-MC-Unique: oz_26MgXMameJNtmDODE2g-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0DF2C2800B47; Fri, 27 Oct 2023 15:54:00 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id D54B75027; Fri, 27 Oct 2023 15:53:58 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, eesposit@redhat.com, eblake@redhat.com, pbonzini@redhat.com, vsementsov@yandex-team.ru, qemu-devel@nongnu.org Subject: [PATCH 13/24] block: Mark bdrv_set_backing_hd_drained() GRAPH_WRLOCK Date: Fri, 27 Oct 2023 17:53:22 +0200 Message-ID: <20231027155333.420094-14-kwolf@redhat.com> In-Reply-To: <20231027155333.420094-1-kwolf@redhat.com> References: <20231027155333.420094-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@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_H4=0.001, RCVD_IN_MSPIKE_WL=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: , X-List-Received-Date: Fri, 27 Oct 2023 15:54:06 -0000 Instead of taking the writer lock internally, require callers to already hold it when calling bdrv_set_backing_hd_drained(). Basically everthing in the function needs the lock and its callers may already want to hold the graph lock and so wouldn't be able to call functions that take it internally. Signed-off-by: Kevin Wolf --- include/block/block-global-state.h | 7 ++++--- block.c | 4 ++-- block/stream.c | 2 ++ 3 files changed, 8 insertions(+), 5 deletions(-) diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index 9a33bd7ef9..a1fd70ec97 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -101,9 +101,10 @@ bdrv_co_open_blockdev_ref(BlockdevRef *ref, Error **errp); int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, Error **errp); -int bdrv_set_backing_hd_drained(BlockDriverState *bs, - BlockDriverState *backing_hd, - Error **errp); +int GRAPH_WRLOCK +bdrv_set_backing_hd_drained(BlockDriverState *bs, BlockDriverState *backing_hd, + Error **errp); + int bdrv_open_backing_file(BlockDriverState *bs, QDict *parent_options, const char *bdref_key, Error **errp); diff --git a/block.c b/block.c index 499b147315..d79a6f41f9 100644 --- a/block.c +++ b/block.c @@ -3557,7 +3557,6 @@ int bdrv_set_backing_hd_drained(BlockDriverState *bs, if (bs->backing) { assert(bs->backing->bs->quiesce_counter > 0); } - bdrv_graph_wrlock(backing_hd); ret = bdrv_set_backing_noperm(bs, backing_hd, tran, errp); if (ret < 0) { @@ -3567,7 +3566,6 @@ int bdrv_set_backing_hd_drained(BlockDriverState *bs, ret = bdrv_refresh_perms(bs, tran, errp); out: tran_finalize(tran, ret); - bdrv_graph_wrunlock(); return ret; } @@ -3580,7 +3578,9 @@ int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, bdrv_ref(drain_bs); bdrv_drained_begin(drain_bs); + bdrv_graph_wrlock(backing_hd); ret = bdrv_set_backing_hd_drained(bs, backing_hd, errp); + bdrv_graph_wrunlock(); bdrv_drained_end(drain_bs); bdrv_unref(drain_bs); diff --git a/block/stream.c b/block/stream.c index 3f5d773535..0b92410c00 100644 --- a/block/stream.c +++ b/block/stream.c @@ -99,7 +99,9 @@ static int stream_prepare(Job *job) } } + bdrv_graph_wrlock(base); bdrv_set_backing_hd_drained(unfiltered_bs, base, &local_err); + bdrv_graph_wrunlock(); /* * This call will do I/O, so the graph can change again from here on.