[pve-devel] [PATCH firewall 1/7] configs: add locking helpers

[Fabian Grünbichler]

to allow some level of safe concurrent config modification, instead of
the current free for all.

Signed-off-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
---

Notes:
    require pve-cluster that provides cfs_lock_firewall, or switching to
    cfs_lock_domain as mentioned in pve-cluster#1
    
    lock_hostfw_conf could also use a node-local lock, but IMHO it's easier to have
    the same locking semantics/interface across all three levels (especially if we
    do the second patch in pve-cluster).
    
    it's easy enough to switch out though.

 src/PVE/Firewall.pm | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/src/PVE/Firewall.pm b/src/PVE/Firewall.pm
index d22b15a..eda39eb 100644
--- a/src/PVE/Firewall.pm
+++ b/src/PVE/Firewall.pm
@@ -3053,6 +3053,8 @@ sub generic_fw_config_parser {
     return $res;
 }
 
+# this is only used to prevent concurrent runs of rule compilation/application
+# see lock_*_conf for cfs locks protectiong config modification
 sub run_locked {
     my ($code, @param) = @_;
 
@@ -3101,6 +3103,18 @@ sub read_local_vm_config {
     return $vmdata;
 };
 
+sub lock_vmfw_conf {
+    my ($vmid, $timeout, $code, @param) = @_;
+
+    die "can't lock VM firewall config for undefined VMID\n"
+	if !defined($vmid);
+
+    my $res = PVE::Cluster::cfs_lock_firewall("vm-$vmid", $timeout, $code, @param);
+    die $@ if $@;
+
+    return $res;
+}
+
 sub load_vmfw_conf {
     my ($cluster_conf, $rule_env, $vmid, $dir) = @_;
 
@@ -3448,6 +3462,15 @@ my $set_global_log_ratelimit = sub {
     }
 };
 
+sub lock_clusterfw_conf {
+    my ($timeout, $code, @param) = @_;
+
+    my $res = PVE::Cluster::cfs_lock_firewall("cluster", $timeout, $code, @param);
+    die $@ if $@;
+
+    return $res;
+}
+
 sub load_clusterfw_conf {
     my ($filename) = @_;
 
@@ -3511,6 +3534,15 @@ sub save_clusterfw_conf {
     }
 }
 
+sub lock_hostfw_conf {
+    my ($timeout, $code, @param) = @_;
+
+    my $res = PVE::Cluster::cfs_lock_firewall("host-$nodename", $timeout, $code, @param);
+    die $@ if $@;
+
+    return $res;
+}
+
 sub load_hostfw_conf {
     my ($cluster_conf, $filename) = @_;
 
-- 
2.20.1