From patchwork Wed Nov 16 13:48:42 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: 13045230 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 91880C43219 for ; Wed, 16 Nov 2022 13:50:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ovImw-0000kg-DT; Wed, 16 Nov 2022 08:49:14 -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 1ovImq-0000gM-O6 for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:11 -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 1ovImk-0007zl-FE for qemu-devel@nongnu.org; Wed, 16 Nov 2022 08:49:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668606538; 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=PJp3ZbKA4Z5qVER4UBk8asMbPlsuCplDYEISzsM1/Lc=; b=hzfc6+pUzC0BMLIv6VvdvJ/a5eZ0v4qwjOduvgAXFmIdWRUfwmik5tmlvVYXA0W0fEoaKA 6cssLsYzp6GDavDyHm4Vt1mZkNyYh4khzJeEGYD7jcQOaWhg+QITR3TMAJOe41DC24kW0z +ezJ9oAB48VKCicfOqcdemW8A8DCbTM= 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-47--fZCKPObOfiyROs1gerTEA-1; Wed, 16 Nov 2022 08:48:56 -0500 X-MC-Unique: -fZCKPObOfiyROs1gerTEA-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 5D823800B23; Wed, 16 Nov 2022 13:48:56 +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 112C04A9266; 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 12/20] block-gen: assert that bdrv_co_pwrite is always called with graph rdlock taken Date: Wed, 16 Nov 2022 08:48:42 -0500 Message-Id: <20221116134850.3051419-13-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_pwrite, we also automatically protect the following other generated_co_wrappers: blk_co_pwrite blk_co_pwritev blk_co_pwritev_part blk_co_pwrite_compressed blk_co_pwrite_zeroes Protecting bdrv_driver_pwritev_compressed() and bdrv_driver_pwritev_compressed() implies that the following BlockDriver callbacks always called with graph rdlock taken: - bdrv_aio_pwritev - bdrv_co_writev - bdrv_co_pwritev - bdrv_co_pwritev_part - bdrv_co_pwritev_compressed - bdrv_co_pwritev_compressed_part Signed-off-by: Emanuele Giuseppe Esposito --- block/block-backend.c | 1 + block/block-copy.c | 8 ++++++-- block/io.c | 2 ++ include/block/block_int-common.h | 6 ++++++ include/block/block_int-io.h | 1 + 5 files changed, 16 insertions(+), 2 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 0686cd6942..d48ec3a2ac 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1363,6 +1363,7 @@ blk_co_do_pwritev_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/block-copy.c b/block/block-copy.c index f33ab1d0b6..dabf461112 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -464,6 +464,8 @@ static coroutine_fn int block_copy_task_run(AioTaskPool *pool, * a full-size buffer or disabled if the copy_range attempt fails. The output * value of @method should be used for subsequent tasks. * Returns 0 on success. + * + * Called with graph rdlock taken. */ static int coroutine_fn block_copy_do_copy(BlockCopyState *s, int64_t offset, int64_t bytes, @@ -554,8 +556,10 @@ static coroutine_fn int block_copy_task_entry(AioTask *task) BlockCopyMethod method = t->method; int ret; - ret = block_copy_do_copy(s, t->req.offset, t->req.bytes, &method, - &error_is_read); + WITH_GRAPH_RDLOCK_GUARD() { + ret = block_copy_do_copy(s, t->req.offset, t->req.bytes, &method, + &error_is_read); + } WITH_QEMU_LOCK_GUARD(&s->lock) { if (s->method == t->method) { diff --git a/block/io.c b/block/io.c index ac12725fb2..9280fb9f38 100644 --- a/block/io.c +++ b/block/io.c @@ -1012,6 +1012,7 @@ static int coroutine_fn bdrv_driver_pwritev(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); @@ -1090,6 +1091,7 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, int64_t offset, BlockDriver *drv = bs->drv; QEMUIOVector local_qiov; int ret; + assert_bdrv_graph_readable(); bdrv_check_qiov_request(offset, bytes, qiov, qiov_offset, &error_abort); diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h index f285a6b8f7..d44f825d95 100644 --- a/include/block/block_int-common.h +++ b/include/block/block_int-common.h @@ -479,6 +479,7 @@ struct BlockDriver { BlockAIOCB *(*bdrv_aio_preadv)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); + /* Called with graph rdlock taken. */ BlockAIOCB *(*bdrv_aio_pwritev)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags, BlockCompletionFunc *cb, void *opaque); @@ -515,6 +516,7 @@ struct BlockDriver { QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); + /* Called with graph rdlock taken. */ int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); @@ -532,10 +534,12 @@ struct BlockDriver { * no larger than 'max_transfer'. * * The buffer in @qiov may point directly to guest memory. + * Called with graph rdlock taken. */ int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags); + /* Called with graph rdlock taken. */ int coroutine_fn (*bdrv_co_pwritev_part)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags); @@ -693,8 +697,10 @@ struct BlockDriver { BlockMeasureInfo *(*bdrv_measure)(QemuOpts *opts, BlockDriverState *in_bs, Error **errp); + /* Called with graph rdlock held. */ int coroutine_fn (*bdrv_co_pwritev_compressed)(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov); + /* Called with graph rdlock held. */ int coroutine_fn (*bdrv_co_pwritev_compressed_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 8bc061ebb8..ae88507d6a 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -69,6 +69,7 @@ static inline int coroutine_fn bdrv_co_pwrite(BdrvChild *child, { QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes); IO_CODE(); + assert_bdrv_graph_readable(); return bdrv_co_pwritev(child, offset, bytes, &qiov, flags); }