[master 13/24] Add guards making sure we are not being tricked with LV seg_type

[dashea]

From: Vratislav Podzimek

Right now, we only support creation of non-linear LVs under some conditions that
allow us avoid trying to do too crazy things. Let's make sure these conditions
are met when a new LVMLogicalVolumeDevice object is being created.
---
 blivet/devices/lvm.py | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/blivet/devices/lvm.py b/blivet/devices/lvm.py
index a836ed4..4cc39e2 100644
--- a/blivet/devices/lvm.py
+++ b/blivet/devices/lvm.py
@@ -595,6 +595,17 @@ def __init__(self, name, parents=None, size=None, uuid=None, seg_type=None,

"""

+        if not exists:
+            if seg_type and seg_type != "linear" and not pvs:
+                raise ValueError("List of PVs has to be given for every non-linear LV")
+            elif (not seg_type or seg_type == "linear") and pvs:
+                if not all(isinstance(pv, LVPVSpec) for pv in pvs):
+                    raise ValueError("Invalid specification of PVs for a linear LV: either no or complete "
+                                     "specification (with all space split into PVs has to be given")
+                elif sum(spec.size for spec in pvs) != size:
+                    raise ValueError("Invalid specification of PVs for a linear LV: the sum of space "
+                                     "assigned to PVs is not equal to the size of the LV")
+
         # When this device's format is set in the superclass constructor it will
         # try to access self.snapshots.
         self.snapshots = []
@@ -1612,7 +1623,7 @@ def __init__(self, name, parents=None, size=None, uuid=None,
             :type sysfs_path: str
             :keyword uuid: the device UUID
             :type uuid: str
-            :keyword seg_type: segment type
+            :keyword seg_type: segment type (only "linear" supported for non-existing ThinPool LVs)
             :type seg_type: str

For non-existent pools only:
@@ -1639,6 +1650,9 @@ def __init__(self, name, parents=None, size=None, uuid=None,
            not blockdev.lvm.is_valid_thpool_chunk_size(chunksize):
             raise ValueError("invalid chunksize value")

+        if not exists and seg_type and seg_type != "linear":
+            raise ValueError("creation of non-linear thin pool LVs is not supported (yet)")
+
         super(LVMThinPoolDevice, self).__init__(name, parents=parents,
                                                 size=size, uuid=uuid,
                                                 fmt=fmt, exists=exists,