Merge pull request #1169 from vojtechtrefny/3.9-devel_lvmdevices-flag

Add flag to control LVM devices file support

blivet/flags.py

@@ -71,6 +71,9 @@ def __init__(self):
         # backup metadata in /etc/lvm/{archive,backup}
         self.lvm_metadata_backup = True
 
+        # set to False to not write new LVM PVs to /etc/lvm/devices/system.devices
+        self.lvm_devices_file = True
+
         # whether to include nodev filesystems in the devicetree
         self.include_nodev = False
 

blivet/formats/lvmpv.py

@@ -37,6 +37,7 @@
 from . import DeviceFormat, register_device_format
 from .. import udev
 from ..static_data.lvm_info import pvs_info, vgs_info
+from ..flags import flags
 
 import logging
 log = logging.getLogger("blivet")
@@ -136,6 +137,10 @@ def lvmdevices_add(self, force=True):
                       self.device, lvm.LVM_DEVICES_FILE)
             return
 
+        if not flags.lvm_devices_file:
+            log.debug("Not adding %s to devices file: 'lvm_devices_file' flag is set to False", self.device)
+            return
+
         try:
             blockdev.lvm.devices_add(self.device)
         except blockdev.LVMError as e:

tests/unit_tests/formats_tests/lvmpv_test.py

@@ -8,6 +8,7 @@
 import unittest
 
 from blivet.formats.lvmpv import LVMPhysicalVolume
+from blivet.flags import flags
 
 
 class LVMPVNodevTestCase(unittest.TestCase):
@@ -71,3 +72,18 @@ def test_lvm_devices(self):
             fmt._create()
 
             mock["blockdev"].lvm.devices_add.assert_not_called()
+
+        with self.patches() as mock:
+            # LVM devices file enabled and devices file exists
+            # but flag set to false -> devices_add should not be called
+            mock["lvm"].HAVE_LVMDEVICES = True
+            mock["os"].path.exists.return_value = True
+            mock["vgs_info"].cache = {}
+            flags.lvm_devices_file = False
+
+            fmt._create()
+
+            mock["blockdev"].lvm.devices_add.assert_not_called()
+
+            # reset the flag back
+            flags.lvm_devices_file = True

tests/unit_tests/formats_tests/methods_test.py

@@ -388,6 +388,7 @@ class LVMPhysicalVolumeMethodsTestCase(FormatMethodsTestCase):
     def set_patches(self):
         super(LVMPhysicalVolumeMethodsTestCase, self).set_patches()
         self.patchers["blockdev"] = patch("blivet.formats.lvmpv.blockdev")
+        self.patchers["vgs_info"] = patch("blivet.formats.lvmpv.vgs_info")
 
     def _test_destroy_backend(self):
         self.format.exists = True