From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <a.lauterer@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 CBB0398A2B
 for <pve-devel@lists.proxmox.com>; Fri, 12 May 2023 14:40:45 +0200 (CEST)
Received: from firstgate.proxmox.com (localhost [127.0.0.1])
 by firstgate.proxmox.com (Proxmox) with ESMTP id AEE1C2DBEC
 for <pve-devel@lists.proxmox.com>; Fri, 12 May 2023 14:40:45 +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 <pve-devel@lists.proxmox.com>; Fri, 12 May 2023 14:40:44 +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 9597441F94
 for <pve-devel@lists.proxmox.com>; Fri, 12 May 2023 14:40:44 +0200 (CEST)
From: Aaron Lauterer <a.lauterer@proxmox.com>
To: pve-devel@lists.proxmox.com
Date: Fri, 12 May 2023 14:40:43 +0200
Message-Id: <20230512124043.888785-7-a.lauterer@proxmox.com>
X-Mailer: git-send-email 2.30.2
In-Reply-To: <20230512124043.888785-1-a.lauterer@proxmox.com>
References: <20230512124043.888785-1-a.lauterer@proxmox.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
X-SPAM-LEVEL: Spam detection results:  0
 AWL -0.096 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 -
 URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See
 http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more
 information. [migrate.pm]
Subject: [pve-devel] [PATCH container v2 6/6] migration: fail when aliased
 volume is detected
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, 12 May 2023 12:40:45 -0000

Aliased volumes (referencing the same volume multiple times) can lead to
unexpected behavior in a migration.

Therefore, stop the migration in such a case.

The check works by comparing the path returned by the storage plugin.
This means that we should be able to catch the common situations where
it can happen:

* by referencing the same volid multiple times
* having a different volid due to an aliased storage: different storage
name but pointing to the same location.

We decided against checking the storages themselves being aliased. It is
not possible to infer that reliably from just the storage configuration
options alone.

Signed-off-by: Aaron Lauterer <a.lauterer@proxmox.com>
---
 src/PVE/LXC/Migrate.pm | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/PVE/LXC/Migrate.pm b/src/PVE/LXC/Migrate.pm
index 8e11be7..e542ce7 100644
--- a/src/PVE/LXC/Migrate.pm
+++ b/src/PVE/LXC/Migrate.pm
@@ -182,6 +182,7 @@ sub phase1 {
     my $volhash = {}; # 'config', 'snapshot' or 'storage' for local volumes
     my $volhash_errors = {};
     my $abort = 0;
+    my $path_to_volid = {};
 
     my $log_error = sub {
 	my ($msg, $volid) = @_;
@@ -236,6 +237,8 @@ sub phase1 {
 	die "owned by other guest (owner = $owner)\n"
 	    if !$owner || ($owner != $self->{vmid});
 
+	$path_to_volid->{$path}->{$volid} = 1;
+
 	if (defined($snapname)) {
 	    # we cannot migrate shapshots on local storage
 	    # exceptions: 'zfspool', 'btrfs'
@@ -282,6 +285,12 @@ sub phase1 {
     # finally all current volumes
     PVE::LXC::Config->foreach_volume_full($conf, { include_unused => 1 }, $test_mp);
 
+    for my $path (keys %$path_to_volid) {
+	my @volids = keys %{$path_to_volid->{$path}};
+	die "detected not supported aliased volumes: '" . join("', '", @volids) . "'"
+	    if (scalar @volids > 1);
+    }
+
     # additional checks for local storage
     foreach my $volid (keys %$volhash) {
 	eval {
-- 
2.30.2