diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index ad10827..18eef46 100755
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -41,11 +41,11 @@ use PVE::Storage::DRBDPlugin;
 use PVE::Storage::PBSPlugin;
 
 # Storage API version. Increment it on changes in storage API interface.
-use constant APIVER => 6;
+use constant APIVER => 7;
 # Age is the number of versions we're backward compatible with.
 # This is like having 'current=APIVER' and age='APIAGE' in libtool,
 # see https://www.gnu.org/software/libtool/manual/html_node/Libtool-versioning.html
-use constant APIAGE => 5;
+use constant APIAGE => 6;
 
 # load standard plugins
 PVE::Storage::DirPlugin->register();
@@ -287,6 +287,18 @@ sub volume_snapshot_delete {
     }
 }
 
+# check if a filesystem on top of a volume needs to flush its journal for
+# consistency (see fsfreeze(8)) before a snapshot is taken - needed for
+# container mountpoints
+sub volume_snapshot_needs_fsfreeze {
+    my ($cfg, $volid) = @_;
+
+    my ($storeid, $volname) = parse_volume_id($volid);
+    my $scfg = storage_config($cfg, $storeid);
+    my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
+    return $plugin->volume_snapshot_needs_fsfreeze();
+}
+
 # check if a volume or snapshot supports a given feature
 # $feature - one of:
 #            clone - linked clone is possible
diff --git a/PVE/Storage/Plugin.pm b/PVE/Storage/Plugin.pm
index 63f68da..a046640 100644
--- a/PVE/Storage/Plugin.pm
+++ b/PVE/Storage/Plugin.pm
@@ -888,6 +888,10 @@ sub volume_snapshot_delete {
     return undef;
 }
 
+sub volume_snapshot_needs_fsfreeze {
+
+    return 0;
+}
 sub storage_can_replicate {
     my ($class, $scfg, $storeid, $format) = @_;
 
diff --git a/PVE/Storage/RBDPlugin.pm b/PVE/Storage/RBDPlugin.pm
index 38f2b46..94df89d 100644
--- a/PVE/Storage/RBDPlugin.pm
+++ b/PVE/Storage/RBDPlugin.pm
@@ -694,6 +694,11 @@ sub volume_snapshot_delete {
     return undef;
 }
 
+sub volume_snapshot_needs_fsfreeze {
+
+    return 1;
+}
+
 sub volume_has_feature {
     my ($class, $scfg, $feature, $storeid, $volname, $snapname, $running) = @_;