Comment # 5 on bug 1172566 from Arvin Schnell

Yes, there is enough space.

# lvs -a -o lv_name,vg_name,lv_attr,lv_size
  LV            VG   Attr       LSize
  giant         test Cwi-C-C-M- 512.00g
  [giant-cache] test Cwi-aoC--- 128.00g
  [giant_corig] test owi-aoC--- 512.00g

# pvs
  PV         VG   Fmt  Attr PSize    PFree
  /dev/sdb   test lvm2 a--   512.00g 384.00g
  /dev/sdc   test lvm2 a--  1024.00g 512.00g

Try to reproduce the problem with the exact sizes I have used.