From patchwork Wed Nov 16 13:48:44 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: 13045254 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 6526FC4332F for ; Wed, 16 Nov 2022 13:57:36 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ovIn3-0000rJ-0t; 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 1ovImw-0000kk-Dx for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:14 -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-00081M-7E for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668606541; 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=y1AhexmEvH/m4MQIk481Hku2zrtOuEL6VbcS01NVR/0=; b=GQtBGfQBaPmNWMrU/5Yzr2jr7jo7LO3cGtEyT22lifBLc9zjsL/skfJRIR3NbHNfy17Zv2 4DZzbsGKcMu0nMgjXlmcw46u0Hhs9/u7O7oDhj6Eob5KZE+cTafmqIeaf9X+LNaeWWmNUm Bg9XhHj23FddYCyKgwNxeEs/DkGAhj4= 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-571-zRTKUX7qP56uIM-KyDHoWQ-1; Wed, 16 Nov 2022 08:48:57 -0500 X-MC-Unique: zRTKUX7qP56uIM-KyDHoWQ-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 15A6F101A56C; 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 BCB624A9266; Wed, 16 Nov 2022 13:48:56 +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 14/20] block-gen: assert that bdrv_co_pread is always called with graph rdlock taken Date: Wed, 16 Nov 2022 08:48:44 -0500 Message-Id: <20221116134850.3051419-15-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 elsewhere else. The strategy is to always take the lock at the function called when the coroutine is created, to avoid recursive locking. By protecting brdv_co_pread, we also automatically protect the following other generated_co_wrappers: blk_co_pread blk_co_preadv blk_co_preadv_part Protecting bdrv_driver_preadv() implies that the following BlockDriver callbacks always called with graph rdlock taken: - bdrv_co_preadv_part - bdrv_co_preadv - bdrv_aio_preadv - bdrv_co_readv Signed-off-by: Emanuele Giuseppe Esposito --- block/block-backend.c | 1 + block/io.c | 1 + block/mirror.c | 6 ++++-- include/block/block_int-common.h | 5 +++++ include/block/block_int-io.h | 1 + tests/unit/test-bdrv-drain.c | 2 ++ 6 files changed, 14 insertions(+), 2 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index d48ec3a2ac..083ed6009e 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1289,6 +1289,7 @@ blk_co_do_preadv_part(BlockBackend *blk, int64_t offset, int64_t bytes, IO_CODE(); blk_wait_while_drained(blk); + GRAPH_RDLOCK_GUARD(); /* Call blk_bs() only after waiting, the graph may have changed */ bs = blk_bs(blk); diff --git a/block/io.c b/block/io.c index 92c74648fb..cfc201ef91 100644 --- a/block/io.c +++ b/block/io.c @@ -942,6 +942,7 @@ static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs, unsigned int nb_sectors; QEMUIOVector local_qiov; int ret; + assert_bdrv_graph_readable(); bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); assert(!(flags & ~bs->supported_read_flags)); diff --git a/block/mirror.c b/block/mirror.c index 251adc5ae0..f509cc1cb1 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -389,8 +389,10 @@ static void coroutine_fn mirror_co_read(void *opaque) op->is_in_flight = true; trace_mirror_one_iteration(s, op->offset, op->bytes); - ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes, - &op->qiov, 0); + WITH_GRAPH_RDLOCK_GUARD() { + ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes, + &op->qiov, 0); + } mirror_read_complete(op, ret); } diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index e8d2e4b6c7..64c5bb64de 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -476,6 +476,7 @@ struct BlockDriver { Error **errp); /* aio */ + /* Called with graph rdlock held. */ BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); @@ -489,6 +490,7 @@ struct BlockDriver { int64_t offset, int bytes, BlockCompletionFunc *cb, void *opaque); + /* Called with graph rdlock held. */ int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); @@ -506,11 +508,14 @@ struct BlockDriver { * no larger than 'max_transfer'. * * The buffer in @qiov may point directly to guest memory. + * + * Called with graph rdlock held. */ int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); + /* Called with graph rdlock held. */ int coroutine_fn (*bdrv_co_preadv_part)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h index ae88507d6a..ac6ad3b3ff 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -60,6 +60,7 @@ static inline int coroutine_fn bdrv_co_pread(BdrvChild *child, { QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); IO_CODE(); + assert_bdrv_graph_readable(); return bdrv_co_preadv(child, offset, bytes, &qiov, flags); } diff --git a/tests/unit/test-bdrv-drain.c b/tests/unit/test-bdrv-drain.c index 2686a8acee..90edc2f5bf 100644 --- a/tests/unit/test-bdrv-drain.c +++ b/tests/unit/test-bdrv-drain.c @@ -967,6 +967,8 @@ static void coroutine_fn test_co_delete_by_drain(void *opaque) void *buffer = g_malloc(65536); QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buffer, 65536); + GRAPH_RDLOCK_GUARD(); + /* Pretend some internal write operation from parent to child. * Important: We have to read from the child, not from the parent! * Draining works by first propagating it all up the tree to the