From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 40DD894B59 for ; Thu, 11 Apr 2024 11:33:14 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 29CB81DE1E for ; Thu, 11 Apr 2024 11:33:14 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS for ; Thu, 11 Apr 2024 11:33:13 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 3558744A35 for ; Thu, 11 Apr 2024 11:33:13 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Date: Thu, 11 Apr 2024 11:29:22 +0200 Message-Id: <20240411092943.57377-2-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240411092943.57377-1-f.ebner@proxmox.com> References: <20240411092943.57377-1-f.ebner@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL -0.072 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: [pve-devel] [PATCH qemu v3 01/22] block/copy-before-write: fix permission X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Apr 2024 09:33:14 -0000 From: Vladimir Sementsov-Ogievskiy In case when source node does not have any parents, the condition still works as required: backup job do create the parent by block_job_create -> block_job_add_bdrv -> bdrv_root_attach_child Still, in this case checking @perm variable doesn't work, as backup job creates the root blk with empty permissions (as it rely on CBW filter to require correct permissions and don't want to create extra conflicts). So, we should not check @perm. The hack may be dropped entirely when transactional insertion of filter (when we don't try to recalculate permissions in intermediate state, when filter does conflict with original parent of the source node) merged (old big series "[PATCH v5 00/45] Transactional block-graph modifying API"[1] and it's current in-flight part is "[PATCH v8 0/7] blockdev-replace"[2]) [1] https://patchew.org/QEMU/20220330212902.590099-1-vsementsov@openvz.org/ [2] https://patchew.org/QEMU/20231017184444.932733-1-vsementsov@yandex-team.ru/ Signed-off-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Fiona Ebner --- block/copy-before-write.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/block/copy-before-write.c b/block/copy-before-write.c index b866e42271..a2dddf6f57 100644 --- a/block/copy-before-write.c +++ b/block/copy-before-write.c @@ -364,9 +364,13 @@ static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c, perm, shared, nperm, nshared); if (!QLIST_EMPTY(&bs->parents)) { - if (perm & BLK_PERM_WRITE) { - *nperm = *nperm | BLK_PERM_CONSISTENT_READ; - } + /* + * Note, that source child may be shared with backup job. Backup job + * does create own blk parent on copy-before-write node, so this + * works even if source node does not have any parents before backup + * start + */ + *nperm = *nperm | BLK_PERM_CONSISTENT_READ; *nshared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); } } -- 2.39.2