[pve-devel] [PATCH pve-container 3/3] vzdump:lxc: sync and skip journal in snapshot mode

[Wolfgang Bumiller]

When using block device based snapshots we cannot mount the
filesystem as it's not clean, and we also can't replay the
journal without write access (as even `-o ro` writes to
devices when replaying a journal (see the linux docs under
Documentation/filesystems/ext4.txt section 3 option 'ro')).

So now we perform a 'sync' after 'lxc-freeze' and before
creating the snapshot, then mount with '-o noload' which
skips the journal entirely and allows us to mount the
filesystem.
---
 src/PVE/LXC.pm        | 7 +++----
 src/PVE/VZDump/LXC.pm | 2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
index c198eaf..9a8110e 100644
--- a/src/PVE/LXC.pm
+++ b/src/PVE/LXC.pm
@@ -1719,20 +1719,19 @@ sub snapshot_create {
 
     my $conf = load_config($vmid);
 
-    my $cmd = "/usr/bin/lxc-freeze -n $vmid";
     my $running = check_running($vmid);
     eval {
 	if ($running) {
-	    PVE::Tools::run_command($cmd);
+	    PVE::Tools::run_command(['/usr/bin/lxc-freeze', '-n', $vmid]);
+	    PVE::Tools::run_command(['/bin/sync']);
 	};
 
 	my $storecfg = PVE::Storage::config();
 	my $rootinfo = parse_ct_mountpoint($conf->{rootfs});
 	my $volid = $rootinfo->{volume};
 
-	$cmd = "/usr/bin/lxc-unfreeze -n $vmid";
 	if ($running) {
-	    PVE::Tools::run_command($cmd);
+	    PVE::Tools::run_command(['/usr/bin/lxc-unfreeze', '-n', $vmid]);
 	};
 
 	PVE::Storage::volume_snapshot($storecfg, $volid, $snapname);
diff --git a/src/PVE/VZDump/LXC.pm b/src/PVE/VZDump/LXC.pm
index a7fafe9..fa1e4ec 100644
--- a/src/PVE/VZDump/LXC.pm
+++ b/src/PVE/VZDump/LXC.pm
@@ -195,7 +195,7 @@ sub snapshot {
     PVE::Storage::activate_volumes($storage_cfg, $volid_list, 'vzdump');
     foreach my $disk (@$disks) {
 	$disk->{dir} = "${rootdir}$disk->{mp}";
-	PVE::LXC::mountpoint_mount($disk, $rootdir, $storage_cfg, 'vzdump');
+	PVE::LXC::mountpoint_mount($disk, $rootdir, $storage_cfg, 'vzdump', ['-o', 'noload']);
     }
 
     $task->{snapdir} = $rootdir;
-- 
2.1.4