[PATCH storage 1/3] zfspool plugin: fix regression for rollback with refquota=none

[Fiona Ebner <f.ebner@proxmox.com>]

As reported in the community forum [0], rollback of a container with a
ZFS dataset with 'refquota=none' would fail. Since commit a9315a0
("fix #6561: zfspool: track refquota for subvolumes via user
properties"), when creating a snapshot, the current refquota is saved
as a user property on the snapshot. The value is queried with '-p' to
get the exact parsable value. In case of 'none', it will be returned
as 0. However, 'zfs set' does not accept an explicit 0 value, but
requires 'none', so restoring the refquota from the user property upon
rollback would fail. Special case the value 0 to fix the issue.

[0]: https://forum.proxmox.com/threads/184113/

Fixes: a9315a0 ("fix #6561: zfspool: track refquota for subvolumes via user properties")
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
 src/PVE/Storage/ZFSPoolPlugin.pm | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/PVE/Storage/ZFSPoolPlugin.pm b/src/PVE/Storage/ZFSPoolPlugin.pm
index 8630744..0531a5d 100644
--- a/src/PVE/Storage/ZFSPoolPlugin.pm
+++ b/src/PVE/Storage/ZFSPoolPlugin.pm
@@ -562,6 +562,7 @@ sub volume_snapshot_rollback {
         my $refquota = $class->zfs_get_properties($scfg, 'pve-storage:refquota', $snapshot_name);
 
         if ($refquota =~ m/^\d+$/) {
+            $refquota = 'none' if $refquota == 0; # zfs does not accept 0 for refquota property
             $class->zfs_request(
                 $scfg, undef, 'set', "refquota=${refquota}", "$scfg->{pool}/$vname",
             );
-- 
2.47.3