Merge pull request #149 from vpodzime/master-lvm_cache

Make blivet aware of internal LVs

blivet/blivet.py

@@ -408,9 +408,8 @@ def lvs(self):
             does not necessarily reflect the actual on-disk state of the
             system's disks.
         """
-        lvs = self.devicetree.getDevicesByType("lvmlv")
-        lvs.sort(key=lambda d: d.name)
-        return lvs
+        lvs = (d for d in self.devices if d.type in ("lvmlv", "lvmthinpool", "lvmthinlv"))
+        return sorted(lvs, key=lambda d: d.name)
 
     @property
     def thinlvs(self):

blivet/devicelibs/lvm.py

@@ -20,6 +20,8 @@
 # Author(s): Dave Lehman <dlehman@redhat.com>
 #
 
+import re
+
 from collections import namedtuple
 from gi.repository import BlockDev as blockdev
 
@@ -115,3 +117,54 @@ def lvm_cc_removeFilterRejectRegexp(regexp):
 def lvm_cc_resetFilter():
     config_args_data["filterRejects"] = []
     config_args_data["filterAccepts"] = []
+
+def determine_parent_lv(vg_name, internal_lv, lvs):
+    """Try to determine which of the lvs is the parent of the internal_lv
+
+    :param str vg_name: name of the VG the internal_lv and lvs belong to
+    :type internal_lv: :class:`~.devices.lvm.LMVInternalLogicalVolumeDevice`
+    :type lvs: :class:`~.devices.lvm.LMVLogicalVolumeDevice`
+
+    """
+    # try name matching first (fast, cheap, often works)
+    for lv in lvs:
+        if internal_lv.lvname == lv.lvname:
+            # skip the internal_lv itself
+            continue
+
+        # check if the lv's name is the name of the internal LV without the suffix
+        # e.g. 'pool' and 'pool_tmeta'
+        if re.match(lv.lvname+internal_lv.name_suffix+"$", internal_lv.lvname):
+            return lv
+
+    # now try checking relations between LVs
+    for lv in lvs:
+        # cache pools are internal LVs of cached LVs
+        try:
+            pool_name = blockdev.lvm.cache_pool_name(vg_name, lv.lvname)
+        except blockdev.LVMError:
+            # cannot determine, just go on
+            pass
+        else:
+            if pool_name == internal_lv.lvname:
+                return lv
+
+        # pools have internal data and metadata LVs
+        try:
+            data_lv_name = blockdev.lvm.data_lv_name(vg_name, lv.lvname)
+        except blockdev.LVMError:
+            # cannot determine, just go on
+            pass
+        else:
+            if data_lv_name == internal_lv.lvname:
+                return lv
+        try:
+            metadata_lv_name = blockdev.lvm.metadata_lv_name(vg_name, lv.lvname)
+        except blockdev.LVMError:
+            # cannot determine, just go on
+            pass
+        else:
+            if metadata_lv_name == internal_lv.lvname:
+                return lv
+
+    return None