[LVM2 PATCH] Add lv_is_internal() to check internal LVs

[LVM2 PATCH] Add lv_is_internal() to check internal LVs

[Jun'ichi Nomura]

Internal LVs ("snapshotX", mirror logs and mimages) should
not be directly manipulated from commands.

Currently, it's allowed in some places, though.
# lvs -a
  LV               VG     Attr   LSize Origin Snap%  Move Log        Copy% 
  lvol0            testvg -wi-a- 4.00M                                     
  lvol2            testvg mwi-a- 4.00M                    lvol2_mlog 100.00
  [lvol2_mimage_0] testvg iwi-ao 4.00M                                     
  [lvol2_mimage_1] testvg iwi-ao 4.00M                                     
  [lvol2_mlog]     testvg lwi-ao 4.00M          
# lvresize -l+1 testvg/lvol2_mimage_1
  Extending logical volume lvol2_mimage_1 to 8.00 MB
# lvconvert -s testvg/lvol2_mimage_1 testvg/lvol0
  Logical volume lvol0 converted to snapshot.
# lvrename testvg/snapshot0 testvg/s
  Renamed "snapshot0" to "s" in volume group "testvg"
# lvconvert -m1 testvg/s
  Logical volume s converted.

Until the stacking of LVs are properly supported,
it's safer to disable them.

Attached patch adds lv_is_internal() to check internal LVs.
lv_is_visible() returns true for "snapshotX" so it can't
directly usable for this purpose.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
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[LVM2 PATCH] Add lv_is_internal() to check internal LVs

[Jun'ichi Nomura]

Jun'ichi Nomura wrote:
> Attached patch adds lv_is_internal() to check internal LVs.
> lv_is_visible() returns true for "snapshotX" so it can't
> directly usable for this purpose.

Oops, sorry. I posted a wrong patch.

> +int lv_is_internal(const struct logical_volume *lv)
> +{
> +	if (lv->status & SNAPSHOT)
> +		return 0;
> +
> +	return lv_is_visible(lv);
> +}

The return value is apparently inverted here.
Internal LVs are either:
  - snapshot (i.e. "snapshotX")
  - not visible

Resending the correct patch.

Thanks,
-- 
Jun'ichi Nomura, NEC Corporation of America
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