[pve-devel] [PATCH storage 1/2] zfs: only use cache when listing images locally

[Fiona Ebner]

The plugin for remote ZFS storages currently also uses the same
list_images() as the plugin for local ZFS storages. The issue with
this is that there is only one cache which does not remember the
target host where the information originated.

Simply restrict the cache to be used for the local ZFS plugin only. An
alternative solution would be to use a cache for each target host, but
that seems a bit more involved and could still be added in the future.

For example, issues can happen during rescan:
1. Via list_images() and zfs_list_zvol(), ZFSPlugin.pm's zfs_request()
   is executed for a remote ZFS.
2. $cache->{zfs} is set to the result of scanning the images there.
3. Another list_images() for a local ZFS storage happens and uses the
   cache with the wrong information.

Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
---
 PVE/Storage/ZFSPlugin.pm     | 7 +++++++
 PVE/Storage/ZFSPoolPlugin.pm | 8 +++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/PVE/Storage/ZFSPlugin.pm b/PVE/Storage/ZFSPlugin.pm
index d4dc2a4..1379bcf 100644
--- a/PVE/Storage/ZFSPlugin.pm
+++ b/PVE/Storage/ZFSPlugin.pm
@@ -419,4 +419,11 @@ sub deactivate_volume {
     return 1;
 }
 
+sub list_images {
+    my ($class, $storeid, $scfg, $vmid, $vollist, $cache) = @_;
+
+    my $zfs_list = $class->zfs_list_zvol($scfg);
+    return $class->zfs_list_images($storeid, $scfg, $vmid, $vollist, $zfs_list);
+}
+
 1;
diff --git a/PVE/Storage/ZFSPoolPlugin.pm b/PVE/Storage/ZFSPoolPlugin.pm
index e264fde..0fa18ce 100644
--- a/PVE/Storage/ZFSPoolPlugin.pm
+++ b/PVE/Storage/ZFSPoolPlugin.pm
@@ -255,10 +255,16 @@ sub list_images {
     my ($class, $storeid, $scfg, $vmid, $vollist, $cache) = @_;
 
     $cache->{zfs} = $class->zfs_list_zvol($scfg) if !$cache->{zfs};
+    return $class->zfs_list_images($storeid, $scfg, $vmid, $vollist, $cache->{zfs});
+}
+
+sub zfs_list_images {
+    my ($class, $storeid, $scfg, $vmid, $vollist, $zfs_list) = @_;
+
     my $zfspool = $scfg->{pool};
     my $res = [];
 
-    if (my $dat = $cache->{zfs}->{$zfspool}) {
+    if (my $dat = $zfs_list->{$zfspool}) {
 
 	foreach my $image (keys %$dat) {
 
-- 
2.30.2