* changed definition of storage device: only "valid" devices are available now

src/cryptobox/core/blockdevice.py

@@ -254,32 +254,31 @@ class Blockdevice:
         cached = CACHE.get(cache_link)
         if not cached is None:
             return cached
+        result = True
 
-        if self.range > 1:
+        # always check the current state of "result" to skip useless checks
+        if result and (self.range > 1):
             ## partitionable blockdevice
-            CACHE.set(cache_link, False)
-            return False
-        if self.size < MINIMUM_STORAGE_SIZE:
+            result = False
+        if result and not self.is_valid():
+            result = False
+        if result and (self.size < MINIMUM_STORAGE_SIZE):
             ## extended partition, unused loop device
-            CACHE.set(cache_link, False)
-            return False
+            result = False
         ## are we the device mapper of a luks device?
-        for slave in self.slaves:
-            if get_blockdevice(slave, self.sysblock_dir,
-                    self.devnode_dir).is_luks():
-                CACHE.set(cache_link, False)
-                return False
-        ## if we are a luks device with exactly one child, then
-        ## we are a storage
-        if (len(self.children) == 1) and self.is_luks():
-            CACHE.set(cache_link, True)
-            return True
-        if self.children:
-            ## a parent blockdevice
-            CACHE.set(cache_link, False)
-            return False
-        CACHE.set(cache_link, True)
-        return True
+        if result:
+            for slave in self.slaves:
+                if get_blockdevice(slave, self.sysblock_dir,
+                        self.devnode_dir).is_luks():
+                    result = False
+        if result and self.children:
+            ## if we are a luks device with exactly one child, then
+            ## we are a storage
+            if not ((len(self.children) == 1) and self.is_luks()):
+                ## a parent blockdevice
+                result = False
+        CACHE.set(cache_link, result)
+        return result
 
 
     def is_partitionable(self):