From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1qwPAI-0004T8-5F for mharc-qemu-devel@gnu.org; Fri, 27 Oct 2023 11:54:26 -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 1qwPA2-0003bX-DH for qemu-devel@nongnu.org; Fri, 27 Oct 2023 11:54:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qwP9y-0002oe-JR for qemu-devel@nongnu.org; Fri, 27 Oct 2023 11:54:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698422044; 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=rFsWMwmZgf1saZoF5DplmDCKHxx8cOFRMV7vZUkejuk=; b=iMdG+FI+XwERL3WO6TsPoClDZX19tq2SllLU83S24V0G9qptLkZpe8YX6rOM3BakeCwaBJ IE9CZfAaLn4vl3KjkrYy469N1zq24MV5kRcE5TTySc/Q/VvjsTTOWy3o8pOG+Ym5gkRKPl 0UA+jf3fCBLLyFyq5/EpkO5HD3MtD7s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-284-a6dnDfGpPS-XBIVFYMcAqA-1; Fri, 27 Oct 2023 11:53:59 -0400 X-MC-Unique: a6dnDfGpPS-XBIVFYMcAqA-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 9DDF5185A786; Fri, 27 Oct 2023 15:53:58 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id 70C605027; Fri, 27 Oct 2023 15:53:57 +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 12/24] block: Mark bdrv_cow_child() and callers GRAPH_RDLOCK Date: Fri, 27 Oct 2023 17:53:21 +0200 Message-ID: <20231027155333.420094-13-kwolf@redhat.com> In-Reply-To: <20231027155333.420094-1-kwolf@redhat.com> References: <20231027155333.420094-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.133.124; 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_H3=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 15:54:12 -0000 This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_cow_child() need to hold a reader lock for the graph because it accesses bs->backing. Signed-off-by: Kevin Wolf --- include/block/block_int-io.h | 5 +++-- block/stream.c | 2 +- qemu-img.c | 11 ++++++++--- 3 files changed, 12 insertions(+), 6 deletions(-) diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h index 17547a2dab..4a7cf2b4fd 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -130,14 +130,15 @@ bdrv_co_refresh_total_sectors(BlockDriverState *bs, int64_t hint); int co_wrapper_mixed_bdrv_rdlock bdrv_refresh_total_sectors(BlockDriverState *bs, int64_t hint); -BdrvChild *bdrv_cow_child(BlockDriverState *bs); +BdrvChild * GRAPH_RDLOCK bdrv_cow_child(BlockDriverState *bs); BdrvChild * GRAPH_RDLOCK bdrv_filter_child(BlockDriverState *bs); BdrvChild * GRAPH_RDLOCK bdrv_filter_or_cow_child(BlockDriverState *bs); BdrvChild * GRAPH_RDLOCK bdrv_primary_child(BlockDriverState *bs); BlockDriverState * GRAPH_RDLOCK bdrv_skip_filters(BlockDriverState *bs); BlockDriverState * GRAPH_RDLOCK bdrv_backing_chain_next(BlockDriverState *bs); -static inline BlockDriverState *bdrv_cow_bs(BlockDriverState *bs) +static inline BlockDriverState * GRAPH_RDLOCK +bdrv_cow_bs(BlockDriverState *bs) { IO_CODE(); return child_bs(bdrv_cow_child(bs)); diff --git a/block/stream.c b/block/stream.c index c32c98339a..3f5d773535 100644 --- a/block/stream.c +++ b/block/stream.c @@ -90,7 +90,7 @@ static int stream_prepare(Job *job) unfiltered_base = bdrv_skip_filters(base); bdrv_graph_rdunlock_main_loop(); - if (bdrv_cow_child(unfiltered_bs)) { + if (unfiltered_bs_cow) { const char *base_id = NULL, *base_fmt = NULL; if (unfiltered_base) { base_id = s->backing_file_str ?: unfiltered_base->filename; diff --git a/qemu-img.c b/qemu-img.c index 33f3ab5fba..5a77f67719 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -3541,7 +3541,7 @@ static int img_rebase(int argc, char **argv) uint8_t *buf_old = NULL; uint8_t *buf_new = NULL; BlockDriverState *bs = NULL, *prefix_chain_bs = NULL; - BlockDriverState *unfiltered_bs; + BlockDriverState *unfiltered_bs, *unfiltered_bs_cow; BlockDriverInfo bdi = {0}; char *filename; const char *fmt, *cache, *src_cache, *out_basefmt, *out_baseimg; @@ -3675,6 +3675,7 @@ static int img_rebase(int argc, char **argv) bdrv_graph_rdlock_main_loop(); unfiltered_bs = bdrv_skip_filters(bs); + unfiltered_bs_cow = bdrv_cow_bs(unfiltered_bs); bdrv_graph_rdunlock_main_loop(); if (compress && !block_driver_can_compress(unfiltered_bs->drv)) { @@ -3710,7 +3711,11 @@ static int img_rebase(int argc, char **argv) /* For safe rebasing we need to compare old and new backing file */ if (!unsafe) { QDict *options = NULL; - BlockDriverState *base_bs = bdrv_cow_bs(unfiltered_bs); + BlockDriverState *base_bs; + + bdrv_graph_rdlock_main_loop(); + base_bs = bdrv_cow_bs(unfiltered_bs); + bdrv_graph_rdunlock_main_loop(); if (base_bs) { blk_old_backing = blk_new(qemu_get_aio_context(), @@ -3876,7 +3881,7 @@ static int img_rebase(int argc, char **argv) * If cluster wasn't changed since prefix_chain, we don't need * to take action */ - ret = bdrv_is_allocated_above(bdrv_cow_bs(unfiltered_bs), + ret = bdrv_is_allocated_above(unfiltered_bs_cow, prefix_chain_bs, false, offset, n, &n); if (ret < 0) { -- 2.41.0