bundles/zfs: use zfs-import-scan instead of zfs-import-cache

Last night, rx300 rebooted. After a reboot, the disks were detected
in another order (but still, all were detected!), so the cachefile did
no longer match, leading to breaking the import.

Running `zpool import` manually worked, because that will ignore the
cachefile. So, why do we depend on the cache file on boot up? The added
reliability of zfs-import-scan beats the speed of zfs-import-cache in
any way.

bundles/zfs/files/zfs-import-scan-override.service

@@ -0,0 +1,10 @@
+[Unit]
+ConditionPathExists=
+
+[Service]
+ExecStart=
+% if node.os == 'arch':
+ExecStart=/usr/bin/zpool import -aN -o cachefile=none
+% else:
+ExecStart=/usr/sbin/zpool import -aN -o cachefile=none
+% endif

bundles/zfs/items.py

@@ -23,11 +23,6 @@ if node.os == 'debian':
             'comment': 'If this fails, do a dist-upgrade, reinstall zfs-dkms, reboot',
         },
     }
-elif node.os == 'arch':
-    for service in ('zfs-import-scan.service', 'zfs-mount.service'):
-        svc_systemd[service] = {}
-    for service in ('zfs.target', 'zfs-import.target'):
-        svc_systemd[service] = {'running': None}
 
 files = {
     '/etc/modprobe.d/zfs.conf': {
@@ -35,6 +30,13 @@ files = {
         'content_type': 'mako',
         'mode': '0755',
     },
+    '/etc/systemd/system/zfs-import-scan.service.d/bundlewrap.conf': {
+        'source': 'zfs-import-scan-override.service',
+        'content_type': 'mako',
+        'triggers': {
+            'action:systemd-reload',
+        },
+    },
     '/etc/zfs-snapshot-config.json': {
         'content': dumps(
             node.metadata.get('zfs/snapshots', {}),
@@ -75,7 +77,27 @@ files = {
 }
 
 svc_systemd = {
+    'zfs-import-scan.service': {
+        'needs': {
+            'file:/etc/systemd/system/zfs-import-scan.service.d/bundlewrap.conf',
+        },
+        'before': {
+            'svc_systemd:zfs-import-cache.service',
+        },
+    },
+    'zfs-import-cache.service': {
+        'running': None,
+        'enabled': False,
+        'masked': True,
+    },
+    'zfs-mount.service': {},
     'zfs-zed': {},
+    'zfs.target': {
+        'running': None,
+    },
+    'zfs-import.target': {
+        'running': None,
+    },
 }
 
 for name, attrs in node.metadata.get('zfs/datasets', {}).items():
@@ -90,8 +112,8 @@ for name, attrs in node.metadata.get('zfs/datasets', {}).items():
 for name, attrs in node.metadata.get('zfs/pools', {}).items():
     zfs_pools[name] = attrs
 
-    if node.os_version[0] > 10:
+    if (not node.os == 'debian' or node.os_version[0] > 10) and 'autotrim' not in attrs:
-        zfs_pools[name]['autotrim'] = attrs.get('autotrim', True)
+        zfs_pools[name]['autotrim'] = True
 
 directories = {
     "/etc/zfs-snapshot-backup-pre.d": {