From patchwork Tue Oct 31 13:54:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fiona Ebner X-Patchwork-Id: 13441564 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 9087AC4332F for ; Tue, 31 Oct 2023 13:59:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qxpEe-0001H7-Iq; Tue, 31 Oct 2023 09:56:48 -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 1qxpDy-0000Ur-QV; Tue, 31 Oct 2023 09:56:08 -0400 Received: from proxmox-new.maurer-it.com ([94.136.29.106]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qxpDw-0000lN-Js; Tue, 31 Oct 2023 09:56:06 -0400 Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 90ACE42A54; Tue, 31 Oct 2023 14:55:51 +0100 (CET) From: Fiona Ebner To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, armbru@redhat.com, eblake@redhat.com, hreitz@redhat.com, kwolf@redhat.com, vsementsov@yandex-team.ru, jsnow@redhat.com, den@virtuozzo.com, t.lamprecht@proxmox.com, alexander.ivanov@virtuozzo.com Subject: [PATCH v4 04/10] block/mirror: determine copy_to_target only once Date: Tue, 31 Oct 2023 14:54:25 +0100 Message-Id: <20231031135431.393137-5-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231031135431.393137-1-f.ebner@proxmox.com> References: <20231031135431.393137-1-f.ebner@proxmox.com> MIME-Version: 1.0 Received-SPF: pass client-ip=94.136.29.106; envelope-from=f.ebner@proxmox.com; helo=proxmox-new.maurer-it.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org In preparation to allow changing the copy_mode via QMP. When running in an iothread, it could be that copy_mode is changed from the main thread in between reading copy_mode in bdrv_mirror_top_pwritev() and reading copy_mode in bdrv_mirror_top_do_write(), so they might end up disagreeing about whether copy_to_target is true or false. Avoid that scenario by determining copy_to_target only once and passing it to bdrv_mirror_top_do_write() as an argument. Signed-off-by: Fiona Ebner Reviewed-by: Vladimir Sementsov-Ogievskiy --- No changes in v4. block/mirror.c | 41 ++++++++++++++++++----------------------- 1 file changed, 18 insertions(+), 23 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 914d723446..31da1526eb 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1463,21 +1463,21 @@ bdrv_mirror_top_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); } +static bool should_copy_to_target(MirrorBDSOpaque *s) +{ + return s->job && s->job->ret >= 0 && + !job_is_cancelled(&s->job->common.job) && + s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; +} + static int coroutine_fn GRAPH_RDLOCK bdrv_mirror_top_do_write(BlockDriverState *bs, MirrorMethod method, - uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, - int flags) + bool copy_to_target, uint64_t offset, uint64_t bytes, + QEMUIOVector *qiov, int flags) { MirrorOp *op = NULL; MirrorBDSOpaque *s = bs->opaque; int ret = 0; - bool copy_to_target = false; - - if (s->job) { - copy_to_target = s->job->ret >= 0 && - !job_is_cancelled(&s->job->common.job) && - s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; - } if (copy_to_target) { op = active_write_prepare(s->job, offset, bytes); @@ -1524,17 +1524,10 @@ static int coroutine_fn GRAPH_RDLOCK bdrv_mirror_top_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) { - MirrorBDSOpaque *s = bs->opaque; QEMUIOVector bounce_qiov; void *bounce_buf; int ret = 0; - bool copy_to_target = false; - - if (s->job) { - copy_to_target = s->job->ret >= 0 && - !job_is_cancelled(&s->job->common.job) && - s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; - } + bool copy_to_target = should_copy_to_target(bs->opaque); if (copy_to_target) { /* The guest might concurrently modify the data to write; but @@ -1551,8 +1544,8 @@ bdrv_mirror_top_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, flags &= ~BDRV_REQ_REGISTERED_BUF; } - ret = bdrv_mirror_top_do_write(bs, MIRROR_METHOD_COPY, offset, bytes, qiov, - flags); + ret = bdrv_mirror_top_do_write(bs, MIRROR_METHOD_COPY, copy_to_target, + offset, bytes, qiov, flags); if (copy_to_target) { qemu_iovec_destroy(&bounce_qiov); @@ -1575,15 +1568,17 @@ static int coroutine_fn GRAPH_RDLOCK bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int64_t bytes, BdrvRequestFlags flags) { - return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_ZERO, offset, bytes, NULL, - flags); + bool copy_to_target = should_copy_to_target(bs->opaque); + return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_ZERO, copy_to_target, + offset, bytes, NULL, flags); } static int coroutine_fn GRAPH_RDLOCK bdrv_mirror_top_pdiscard(BlockDriverState *bs, int64_t offset, int64_t bytes) { - return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_DISCARD, offset, bytes, - NULL, 0); + bool copy_to_target = should_copy_to_target(bs->opaque); + return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_DISCARD, copy_to_target, + offset, bytes, NULL, 0); } static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs)