[pve-devel] [PATCH guest-common 2/2] config: activate affected storages for snapshot operations

[Fabian Ebner]

For snapshot creation, the storage for the vmstate file is activated
via vdisk_alloc when the state file is created.

Do not activate the volumes themselves, as that has unnecessary side
effects (e.g. waiting for zvol device link for ZFS, mapping the volume
for RBD). If a storage can only do snapshot operations on a volume
that has been activated, it needs to activate the volume itself.

The actual implementation will be in the plugins, to be able to skip
CD ROM drives and bind-mounts, etc. when iterating over the volumes.

Signed-off-by: Fabian Ebner <f.ebner at proxmox.com>
---
 src/PVE/AbstractConfig.pm | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/PVE/AbstractConfig.pm b/src/PVE/AbstractConfig.pm
index b3f70f2..d4f3d44 100644
--- a/src/PVE/AbstractConfig.pm
+++ b/src/PVE/AbstractConfig.pm
@@ -776,6 +776,13 @@ sub __snapshot_commit {
     $class->lock_config($vmid, $updatefn);
 }
 
+# Activates the storages affected by the snapshot operations.
+sub __snapshot_activate_storages {
+    my ($class, $conf, $include_vmstate) = @_;
+
+    return; # FIXME PVE 8.x change to die 'implement me' and bump Breaks for older plugins
+}
+
 # Creates a snapshot for the VM/CT.
 sub snapshot_create {
     my ($class, $vmid, $snapname, $save_vmstate, $comment) = @_;
@@ -791,6 +798,8 @@ sub snapshot_create {
     my $drivehash = {};
 
     eval {
+	$class->__snapshot_activate_storages($conf, 0);
+
 	if ($freezefs) {
 	    $class->__snapshot_freeze($vmid, 0);
 	}
@@ -836,6 +845,8 @@ sub snapshot_delete {
 
     die "snapshot '$snapname' does not exist\n" if !defined($snap);
 
+    $class->__snapshot_activate_storages($snap, 1) if !$drivehash;
+
     $class->set_lock($vmid, 'snapshot-delete')
 	if (!$drivehash); # doesn't already have a 'snapshot' lock
 
@@ -970,6 +981,8 @@ sub snapshot_rollback {
 	$snap = $get_snapshot_config->($conf);
 
 	if ($prepare) {
+	    $class->__snapshot_activate_storages($snap, 1);
+
 	    my $repl_conf = PVE::ReplicationConfig->new();
 	    if ($repl_conf->check_for_existing_jobs($vmid, 1)) {
 		# remove all replication snapshots
-- 
2.30.2