[lvm-devel] Re: [PATCH] Fix handling of snapshots with virtual origin.

[Mikulas Patocka]

It fixes the problem, but here is another one:

[gerlinda:~]# rmmod dm_zero
[gerlinda:~]# lvcreate -n vo -s --virtualoriginsize 64M -L 24M vg1
  Can't expand LV vo_vorigin: zero target support missing from kernel?
  Couldn't create virtual origin for LV vo
[gerlinda:~]# lvs
  LV      VG   Attr   LSize  Origin Snap%  Move Log         Copy%  Convert
  bla     vg1  -wi--- 24.00M
  er      vg1  vwi-a- 16.00M
  hid     vg1  owi--- 20.00M
  hid_sn  vg1  swi--- 20.00M hid
  hid_sn2 vg1  swi--- 24.00M hid
  mirror  vg1  mwi--- 30.00M                    mirror_mlog
[gerlinda:~]# lvcreate -n vo -s --virtualoriginsize 64M -L 24M vg1
  Internal error: Duplicate LV name vo_vorigin detected in vg1.
  Couldn't create virtual origin for LV vo
  Internal error: Duplicate LV name vo_vorigin detected in vg1.
  Manual intervention may be required to remove abandoned LV(s) before 
retrying.
[gerlinda:~]# lvs
  LV      VG   Attr   LSize  Origin Snap%  Move Log         Copy%  Convert
  bla     vg1  -wi--- 24.00M
  er      vg1  vwi-a- 16.00M
  hid     vg1  owi--- 20.00M
  hid_sn  vg1  swi--- 20.00M hid
  hid_sn2 vg1  swi--- 24.00M hid
  mirror  vg1  mwi--- 30.00M                    mirror_mlog
  vo      vg1  -wi--- 24.00M
[gerlinda:~]# lvremove vg1/vo
  Logical volume "vo" successfully removed

... after this, the vg contains junk invisible lv vo_vorigin in its 
metadata. It can be removed, but it can't be seen. (in fact, the junk lv 
is created on the first activation command if the module dm_zero is not 
loaded in the kernel)

Mikulas