From patchwork Fri Oct 27 15:53:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13455677 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1qwPAM-0004zc-Ri for mharc-qemu-devel@gnu.org; Fri, 27 Oct 2023 11:54:30 -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 1qwP9z-0003aV-QW for qemu-devel@nongnu.org; Fri, 27 Oct 2023 11:54:08 -0400 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 1qwP9w-0002nq-57 for qemu-devel@nongnu.org; Fri, 27 Oct 2023 11:54:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1698422043; 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=y06hjOIaF//T00YKjclIkGs0hl2F8sNFdUr6SPtDbiU=; b=XjAm3C+qwfY/n0szLzoKANP57div5gcfLkdloSc3mm3ZOe1qo5O83GVzEAX6tYW1D//+dQ PBGgJ0rBOv/VDXlKWPcLj4CVxOzenaNcClhFQ0VlD7y7w3JksEwsOCbHeAvkoT5eMyu94w 6/ulypVNijqEe3hD2JYb1JvcwYN4mSA= 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-445-qnuEtd7eMzqddXl-IODWtg-1; Fri, 27 Oct 2023 11:53:56 -0400 X-MC-Unique: qnuEtd7eMzqddXl-IODWtg-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 C21038021BE; Fri, 27 Oct 2023 15:53:55 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.78]) by smtp.corp.redhat.com (Postfix) with ESMTP id 94D485027; Fri, 27 Oct 2023 15:53:54 +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 10/24] block: Mark bdrv_chain_contains() and callers GRAPH_RDLOCK Date: Fri, 27 Oct 2023 17:53:19 +0200 Message-ID: <20231027155333.420094-11-kwolf@redhat.com> In-Reply-To: <20231027155333.420094-1-kwolf@redhat.com> References: <20231027155333.420094-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 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 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 15:54:10 -0000 This adds GRAPH_RDLOCK annotations to declare that callers of bdrv_chain_contains() need to hold a reader lock for the graph because it calls bdrv_filter_or_cow_bs(), which accesses bs->file/backing. Signed-off-by: Kevin Wolf --- include/block/block-global-state.h | 4 ++- block.c | 1 - block/block-copy.c | 2 ++ blockdev.c | 48 +++++++++++++++++------------- 4 files changed, 32 insertions(+), 23 deletions(-) diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index 545708c35a..9a33bd7ef9 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -199,7 +199,9 @@ XDbgBlockGraph * GRAPH_RDLOCK bdrv_get_xdbg_block_graph(Error **errp); BlockDriverState *bdrv_lookup_bs(const char *device, const char *node_name, Error **errp); -bool bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base); +bool GRAPH_RDLOCK +bdrv_chain_contains(BlockDriverState *top, BlockDriverState *base); + BlockDriverState *bdrv_next_node(BlockDriverState *bs); BlockDriverState *bdrv_next_all_states(BlockDriverState *bs); diff --git a/block.c b/block.c index dc1980ee42..bb322df7d8 100644 --- a/block.c +++ b/block.c @@ -6524,7 +6524,6 @@ 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/block-copy.c b/block/block-copy.c index 6b2be3d204..9ee3dd7ef5 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -399,7 +399,9 @@ BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target, * For more information see commit f8d59dfb40bb and test * tests/qemu-iotests/222 */ + bdrv_graph_rdlock_main_loop(); is_fleecing = bdrv_chain_contains(target->bs, source->bs); + bdrv_graph_rdunlock_main_loop(); s = g_new(BlockCopyState, 1); *s = (BlockCopyState) { diff --git a/blockdev.c b/blockdev.c index 0d9c821e66..368cec3747 100644 --- a/blockdev.c +++ b/blockdev.c @@ -2441,11 +2441,12 @@ void qmp_block_stream(const char *job_id, const char *device, aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); + bdrv_graph_rdlock_main_loop(); if (base) { base_bs = bdrv_find_backing_image(bs, base); if (base_bs == NULL) { error_setg(errp, "Can't find '%s' in the backing chain", base); - goto out; + goto out_rdlock; } assert(bdrv_get_aio_context(base_bs) == aio_context); } @@ -2453,38 +2454,36 @@ void qmp_block_stream(const char *job_id, const char *device, if (base_node) { base_bs = bdrv_lookup_bs(NULL, base_node, errp); if (!base_bs) { - goto out; + goto out_rdlock; } if (bs == base_bs || !bdrv_chain_contains(bs, base_bs)) { error_setg(errp, "Node '%s' is not a backing image of '%s'", base_node, device); - goto out; + goto out_rdlock; } assert(bdrv_get_aio_context(base_bs) == aio_context); - bdrv_graph_rdlock_main_loop(); bdrv_refresh_filename(base_bs); - bdrv_graph_rdunlock_main_loop(); } if (bottom) { bottom_bs = bdrv_lookup_bs(NULL, bottom, errp); if (!bottom_bs) { - goto out; + goto out_rdlock; } if (!bottom_bs->drv) { error_setg(errp, "Node '%s' is not open", bottom); - goto out; + goto out_rdlock; } if (bottom_bs->drv->is_filter) { error_setg(errp, "Node '%s' is a filter, use a non-filter node " "as 'bottom'", bottom); - goto out; + goto out_rdlock; } if (!bdrv_chain_contains(bs, bottom_bs)) { error_setg(errp, "Node '%s' is not in a chain starting from '%s'", bottom, device); - goto out; + goto out_rdlock; } assert(bdrv_get_aio_context(bottom_bs) == aio_context); } @@ -2492,14 +2491,12 @@ 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) */ - 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)) { if (bdrv_op_is_blocked(iter, BLOCK_OP_TYPE_STREAM, errp)) { - bdrv_graph_rdunlock_main_loop(); - goto out; + goto out_rdlock; } } bdrv_graph_rdunlock_main_loop(); @@ -2531,6 +2528,11 @@ void qmp_block_stream(const char *job_id, const char *device, out: aio_context_release(aio_context); + return; + +out_rdlock: + bdrv_graph_rdunlock_main_loop(); + aio_context_release(aio_context); } void qmp_block_commit(const char *job_id, const char *device, @@ -3416,39 +3418,38 @@ void qmp_change_backing_file(const char *device, aio_context = bdrv_get_aio_context(bs); aio_context_acquire(aio_context); + bdrv_graph_rdlock_main_loop(); + image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err); if (local_err) { error_propagate(errp, local_err); - goto out; + goto out_rdlock; } if (!image_bs) { error_setg(errp, "image file not found"); - goto out; + goto out_rdlock; } - bdrv_graph_rdlock_main_loop(); if (bdrv_find_base(image_bs) == image_bs) { error_setg(errp, "not allowing backing file change on an image " "without a backing file"); - bdrv_graph_rdunlock_main_loop(); - goto out; + goto out_rdlock; } /* even though we are not necessarily operating on bs, we need it to * determine if block ops are currently prohibited on the chain */ if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) { - bdrv_graph_rdunlock_main_loop(); - goto out; + goto out_rdlock; } - bdrv_graph_rdunlock_main_loop(); /* final sanity check */ if (!bdrv_chain_contains(bs, image_bs)) { error_setg(errp, "'%s' and image file are not in the same chain", device); - goto out; + goto out_rdlock; } + bdrv_graph_rdunlock_main_loop(); /* if not r/w, reopen to make r/w */ ro = bdrv_is_read_only(image_bs); @@ -3476,6 +3477,11 @@ void qmp_change_backing_file(const char *device, out: aio_context_release(aio_context); + return; + +out_rdlock: + bdrv_graph_rdunlock_main_loop(); + aio_context_release(aio_context); } void qmp_blockdev_add(BlockdevOptions *options, Error **errp)