Add constants for file-based storage

Reviewed-by: iustinp

lib/constants.py

@@ -87,6 +87,7 @@ DT_PLAIN = "plain"
 DT_LOCAL_RAID1 = "local_raid1"
 DT_REMOTE_RAID1 = "remote_raid1"
 DT_DRBD8 = "drbd"
+DT_FILE = "file"
 
 # the set of network-mirrored disk templates
 DTS_NET_MIRROR = frozenset([DT_REMOTE_RAID1, DT_DRBD8])
@@ -96,6 +97,11 @@ LD_LV = "lvm"
 LD_MD_R1 = "md_raid1"
 LD_DRBD7 = "drbd"
 LD_DRBD8 = "drbd8"
+LD_FILE = "file"
+
+# file backend driver
+FD_LOOP = "loop"
+FD_BLKTAP = "blktap"
 
 # the set of drbd-like disk types
 LDS_DRBD = frozenset([LD_DRBD7, LD_DRBD8])
@@ -111,7 +117,9 @@ INSTANCE_IMPORT = "import"
 
 DISK_TEMPLATES = frozenset([DT_DISKLESS, DT_PLAIN,
                             DT_LOCAL_RAID1, DT_REMOTE_RAID1,
-                            DT_DRBD8])
+                            DT_DRBD8, DT_FILE])
+
+FILE_DRIVER = frozenset([FD_LOOP, FD_BLKTAP])
 
 # import/export config options
 INISECT_EXP = "export"