[PATCH qemu-server v2 6/7] agent: fs freeze: harmonize checks for guest fs freeze

[Fiona Ebner <f.ebner@proxmox.com>]

Puts the logic inside the agent module, rather than duplicating it in
three different places.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---

Changes in v2:
* Adapt to new should_fs_freeze() function.
* Use subroutine signature.
* Rename guest_fsfreeze_applicable() to guest_fs_freeze_applicable().
* Simplify log function (usage) in guest_fsfreeze_applicable().
* Drop $is_backup argument from guest_fs_freeze_applicable() now that
  there is no backup-specific option anymore (is an alias for the
  general one).

 src/PVE/QemuConfig.pm          | 14 ++++++--------
 src/PVE/QemuServer/Agent.pm    | 31 +++++++++++++++++++++++++++++++
 src/PVE/QemuServer/BlockJob.pm | 11 ++---------
 src/PVE/VZDump/QemuServer.pm   | 20 +++++++-------------
 4 files changed, 46 insertions(+), 30 deletions(-)

diff --git a/src/PVE/QemuConfig.pm b/src/PVE/QemuConfig.pm
index eedb34f9..5feae68d 100644
--- a/src/PVE/QemuConfig.pm
+++ b/src/PVE/QemuConfig.pm
@@ -292,17 +292,15 @@ sub __snapshot_check_running {
 sub __snapshot_check_freeze_needed {
     my ($class, $vmid, $config, $save_vmstate) = @_;
 
+    my $freeze_needed = 0;
     my $running = $class->__snapshot_check_running($vmid);
+
     if (!$save_vmstate) {
-        return (
-            $running,
-            $running
-                && PVE::QemuServer::Agent::should_fs_freeze($config->{agent})
-                && PVE::QemuServer::Agent::qga_check_running($vmid),
-        );
-    } else {
-        return ($running, 0);
+        $freeze_needed =
+            PVE::QemuServer::Agent::guest_fs_freeze_applicable($config->{agent}, $vmid);
     }
+
+    return ($running, $freeze_needed);
 }
 
 sub __snapshot_freeze {
diff --git a/src/PVE/QemuServer/Agent.pm b/src/PVE/QemuServer/Agent.pm
index e63b09f2..c8cd334f 100644
--- a/src/PVE/QemuServer/Agent.pm
+++ b/src/PVE/QemuServer/Agent.pm
@@ -276,4 +276,35 @@ sub guest_fs_thaw($vmid) {
     return;
 }
 
+=head3 guest_fs_freeze_applicable
+
+    if (guest_fs_freeze_applicable($agent_str, $vmid, $logfunc)) {
+        guest_fs_freeze($vmid);
+    }
+
+Check if the file systems of the guest C<$vmid> should be frozen according to the guest agent
+property string C<$agent_str> and if freezing is actionable in practice, i.e. guest agent running.
+Logs a message if skipped. Using a custom log function via C<$logfunc> is supported. Otherwise,
+C<print()> and C<warn()> will be used.
+
+=cut
+
+sub guest_fs_freeze_applicable($agent_str, $vmid, $logfunc = undef) {
+    $logfunc //= sub($msg, $level = 'info') {
+        $level eq 'info' ? print("$msg\n") : warn("$msg\n");
+    };
+
+    if (!should_fs_freeze($agent_str)) {
+        $logfunc->("skipping guest filesystem freeze - disabled in VM options");
+        return;
+    }
+
+    if (!qga_check_running($vmid, 1)) {
+        $logfunc->("skipping guest filesystem freeze - agent configured but not running?");
+        return;
+    }
+
+    return 1;
+}
+
 1;
diff --git a/src/PVE/QemuServer/BlockJob.pm b/src/PVE/QemuServer/BlockJob.pm
index 93a1ce60..3fc5af3b 100644
--- a/src/PVE/QemuServer/BlockJob.pm
+++ b/src/PVE/QemuServer/BlockJob.pm
@@ -162,20 +162,13 @@ sub monitor {
                 last if $completion eq 'skip' || $completion eq 'auto';
 
                 if ($vmiddst && $vmiddst != $vmid) {
-                    my $freeze_enabled = PVE::QemuServer::Agent::should_fs_freeze($qga);
-                    my $should_fsfreeze = $freeze_enabled && qga_check_running($vmid);
+                    my $should_fsfreeze =
+                        PVE::QemuServer::Agent::guest_fs_freeze_applicable($qga, $vmid);
                     if ($should_fsfreeze) {
                         print "issuing guest agent 'guest-fsfreeze-freeze' command\n";
                         eval { PVE::QemuServer::Agent::guest_fs_freeze($vmid); };
                         warn $@ if $@;
                     } else {
-                        if (!$freeze_enabled) {
-                            print "skipping guest-agent 'guest-fsfreeze-freeze', disabled in VM"
-                                . " options\n";
-                        } else {
-                            print "skipping guest agent 'guest-fsfreeze-freeze' command: the"
-                                . " agent is not running inside of the guest\n";
-                        }
                         print "suspend vm\n";
                         eval { PVE::QemuServer::RunState::vm_suspend($vmid, 1); };
                         warn $@ if $@;
diff --git a/src/PVE/VZDump/QemuServer.pm b/src/PVE/VZDump/QemuServer.pm
index 9952cff1..86909d28 100644
--- a/src/PVE/VZDump/QemuServer.pm
+++ b/src/PVE/VZDump/QemuServer.pm
@@ -1098,20 +1098,14 @@ sub qga_fs_freeze {
         || !$self->{vm_was_running}
         || $self->{vm_was_paused};
 
-    my $conf = $self->{vmlist}->{$vmid};
+    my $agent_str = $self->{vmlist}->{$vmid}->{agent};
 
-    if (!PVE::QemuServer::Agent::get_qga_key($conf, 'enabled')) {
-        $self->loginfo("skipping guest-agent 'fs-freeze', agent not configured in VM options");
-        return;
-    }
-
-    if (!PVE::QemuServer::Agent::qga_check_running($vmid, 1)) {
-        $self->loginfo("skipping guest-agent 'fs-freeze', agent configured but not running?");
-        return;
-    }
-
-    if (!PVE::QemuServer::Agent::should_fs_freeze($conf->{agent})) {
-        $self->loginfo("skipping guest-agent 'fs-freeze', disabled in VM options");
+    my $logfunc = sub {
+        my ($msg, $level) = @_; # Note that msg and level are swapped intentionally here.
+        $level //= 'info';
+        $self->log($level, $msg);
+    };
+    if (!PVE::QemuServer::Agent::guest_fs_freeze_applicable($agent_str, $vmid, $logfunc)) {
         return;
     }
 
-- 
2.47.3