From patchwork Tue Nov 7 18:45:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13449212 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 27398C4332F for ; Tue, 7 Nov 2023 18:48:25 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1r0R5w-00044n-TV; Tue, 07 Nov 2023 13:46:41 -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 1r0R5f-0003vI-I9 for qemu-devel@nongnu.org; Tue, 07 Nov 2023 13:46:23 -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 1r0R5c-0001Tl-CF for qemu-devel@nongnu.org; Tue, 07 Nov 2023 13:46:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1699382775; 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=Ikpzi/J9P2vxFqXxR3blvPQASsFGFzG0SWOjp/o3suY=; b=bzwmw63rTpMf4AG5f6I6NiR8R+c445yJMVVd0cHtT2SpQQNMJRRcZlTbM6gYZO10uUdZkZ 1EpCrJVT0HYmA24QPa+pq7yyGaAc2DKr8xjYTiATP2Sw4/ie75UVd5qkr79ViROoRZYmfM FNWFN40HtVr/V63+HkXV14tuHR9sOjE= 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-317-M5-Sq2HwOTGWW8Q7-zPFNA-1; Tue, 07 Nov 2023 13:46:12 -0500 X-MC-Unique: M5-Sq2HwOTGWW8Q7-zPFNA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (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 34DC0832D6E for ; Tue, 7 Nov 2023 18:46:12 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.197]) by smtp.corp.redhat.com (Postfix) with ESMTP id AD970C1290F; Tue, 7 Nov 2023 18:46:11 +0000 (UTC) From: Kevin Wolf To: qemu-devel@nongnu.org Cc: kwolf@redhat.com Subject: [PULL 06/25] block: Mark bdrv_filter_or_cow_bs() and callers GRAPH_RDLOCK Date: Tue, 7 Nov 2023 19:45:46 +0100 Message-ID: <20231107184605.236540-7-kwolf@redhat.com> In-Reply-To: <20231107184605.236540-1-kwolf@redhat.com> References: <20231107184605.236540-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 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, 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 This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_filter_or_cow_bs() need to hold a reader lock for the graph because it calls bdrv_filter_or_cow_child(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf Message-ID: <20231027155333.420094-7-kwolf@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- include/block/block_int-io.h | 3 ++- block.c | 31 ++++++++++++++++++------------- block/stream.c | 4 ++++ blockdev.c | 2 +- nbd/server.c | 6 ++++++ 5 files changed, 31 insertions(+), 15 deletions(-) diff --git a/include/block/block_int-io.h b/include/block/block_int-io.h index 26bff94e4e..6800af7590 100644 --- a/include/block/block_int-io.h +++ b/include/block/block_int-io.h @@ -150,7 +150,8 @@ bdrv_filter_bs(BlockDriverState *bs) return child_bs(bdrv_filter_child(bs)); } -static inline BlockDriverState *bdrv_filter_or_cow_bs(BlockDriverState *bs) +static inline BlockDriverState * GRAPH_RDLOCK +bdrv_filter_or_cow_bs(BlockDriverState *bs) { IO_CODE(); return child_bs(bdrv_filter_or_cow_child(bs)); diff --git a/block.c b/block.c index 5f92eb4950..a6060eddbc 100644 --- a/block.c +++ b/block.c @@ -5435,17 +5435,6 @@ static int bdrv_replace_node_common(BlockDriverState *from, GLOBAL_STATE_CODE(); - if (detach_subchain) { - assert(bdrv_chain_contains(from, to)); - assert(from != to); - for (to_cow_parent = from; - bdrv_filter_or_cow_bs(to_cow_parent) != to; - to_cow_parent = bdrv_filter_or_cow_bs(to_cow_parent)) - { - ; - } - } - /* Make sure that @from doesn't go away until we have successfully attached * all of its parents to @to. */ bdrv_ref(from); @@ -5457,6 +5446,17 @@ static int bdrv_replace_node_common(BlockDriverState *from, bdrv_graph_wrlock(to); + if (detach_subchain) { + assert(bdrv_chain_contains(from, to)); + assert(from != to); + for (to_cow_parent = from; + bdrv_filter_or_cow_bs(to_cow_parent) != to; + to_cow_parent = bdrv_filter_or_cow_bs(to_cow_parent)) + { + ; + } + } + /* * Do the replacement without permission update. * Replacement may influence the permissions, we should calculate new @@ -5504,10 +5504,14 @@ int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, int bdrv_drop_filter(BlockDriverState *bs, Error **errp) { + BlockDriverState *child_bs; + GLOBAL_STATE_CODE(); + bdrv_graph_rdlock_main_loop(); + child_bs = bdrv_filter_or_cow_bs(bs); + bdrv_graph_rdunlock_main_loop(); - return bdrv_replace_node_common(bs, bdrv_filter_or_cow_bs(bs), true, true, - errp); + return bdrv_replace_node_common(bs, child_bs, true, true, errp); } /* @@ -6509,6 +6513,7 @@ bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base) { GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); while (top && top != base) { top = bdrv_filter_or_cow_bs(top); diff --git a/block/stream.c b/block/stream.c index 51333e460b..2781441191 100644 --- a/block/stream.c +++ b/block/stream.c @@ -60,6 +60,8 @@ static int stream_prepare(Job *job) Error *local_err = NULL; int ret = 0; + GLOBAL_STATE_CODE(); + /* We should drop filter at this point, as filter hold the backing chain */ bdrv_cor_filter_drop(s->cor_filter_bs); s->cor_filter_bs = NULL; @@ -78,8 +80,10 @@ static int stream_prepare(Job *job) bdrv_drained_begin(unfiltered_bs_cow); } + bdrv_graph_rdlock_main_loop(); base = bdrv_filter_or_cow_bs(s->above_base); unfiltered_base = bdrv_skip_filters(base); + bdrv_graph_rdunlock_main_loop(); if (bdrv_cow_child(unfiltered_bs)) { const char *base_id = NULL, *base_fmt = NULL; diff --git a/blockdev.c b/blockdev.c index 148df99e00..4cb8e1d91a 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2501,8 +2501,8 @@ void qmp_block_stream(const char *job_id, const char *device, /* * Check for op blockers in the whole chain between bs and base (or bottom) */ - iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs; bdrv_graph_rdlock_main_loop(); + iter_end = bottom ? bdrv_filter_or_cow_bs(bottom_bs) : base_bs; for (iter = bs; iter && iter != iter_end; iter = bdrv_filter_or_cow_bs(iter)) { diff --git a/nbd/server.c b/nbd/server.c index 859c163d19..895cf0a752 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1689,6 +1689,7 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, size_t i; int ret; + GLOBAL_STATE_CODE(); assert(exp_args->type == BLOCK_EXPORT_TYPE_NBD); if (!nbd_server_is_running()) { @@ -1743,6 +1744,8 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, } exp->size = QEMU_ALIGN_DOWN(size, BDRV_SECTOR_SIZE); + bdrv_graph_rdlock_main_loop(); + for (bitmaps = arg->bitmaps; bitmaps; bitmaps = bitmaps->next) { exp->nr_export_bitmaps++; } @@ -1825,9 +1828,12 @@ static int nbd_export_create(BlockExport *blk_exp, BlockExportOptions *exp_args, QTAILQ_INSERT_TAIL(&exports, exp, next); + bdrv_graph_rdunlock_main_loop(); + return 0; fail: + bdrv_graph_rdunlock_main_loop(); g_free(exp->export_bitmaps); g_free(exp->name); g_free(exp->description);