From mboxrd@z Thu Jan 1 00:00:00 1970
Return-Path: <f.ebner@proxmox.com>
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 AE973B98F6
for <pve-devel@lists.proxmox.com>; Fri, 15 Mar 2024 11:25:38 +0100 (CET)
Received: from firstgate.proxmox.com (localhost [127.0.0.1])
by firstgate.proxmox.com (Proxmox) with ESMTP id 7D1AC1913C
for <pve-devel@lists.proxmox.com>; Fri, 15 Mar 2024 11:25:08 +0100 (CET)
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 <pve-devel@lists.proxmox.com>; Fri, 15 Mar 2024 11:25:06 +0100 (CET)
Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1])
by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 26FE548A24
for <pve-devel@lists.proxmox.com>; Fri, 15 Mar 2024 11:25:06 +0100 (CET)
From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Date: Fri, 15 Mar 2024 11:24:42 +0100
Message-Id: <20240315102502.84163-2-f.ebner@proxmox.com>
X-Mailer: git-send-email 2.39.2
In-Reply-To: <20240315102502.84163-1-f.ebner@proxmox.com>
References: <20240315102502.84163-1-f.ebner@proxmox.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
X-SPAM-LEVEL: Spam detection results: 0
AWL -0.070 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
T_SCC_BODY_TEXT_LINE -0.01 -
Subject: [pve-devel] [PATCH qemu v2 01/21] 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 <pve-devel.lists.proxmox.com>
List-Unsubscribe: <https://lists.proxmox.com/cgi-bin/mailman/options/pve-devel>,
<mailto:pve-devel-request@lists.proxmox.com?subject=unsubscribe>
List-Archive: <http://lists.proxmox.com/pipermail/pve-devel/>
List-Post: <mailto:pve-devel@lists.proxmox.com>
List-Help: <mailto:pve-devel-request@lists.proxmox.com?subject=help>
List-Subscribe: <https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel>,
<mailto:pve-devel-request@lists.proxmox.com?subject=subscribe>
X-List-Received-Date: Fri, 15 Mar 2024 10:25:38 -0000
From: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
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 <vsementsov@yandex-team.ru>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
Changes in v2:
* update to latest upstream version
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