[PATCH] Add possibility to exclude internal VG names and uuids in lists returned from liblvm (and lvmcache)

[Dave Wysochanski <dwysocha@redhat.com>]

On Tue, 2010-01-26 at 15:14 +0100, Peter Rajnoha wrote:
> This is related to liblvm and its lvm_list_vg_names() and lvm_list_vg_uuids() functions
> where we should not expose internal VG names/uuids (the ones with "#" prefix )through the
> interface. Otherwise, we could end up with library users opening internal VGs which will
> initiate locking mechanism that won't be cleaned up properly.
> 
> "#orphans_{lvm1, lvm2, pool}" names are treated in a special way, they are truncated first
> to "orphans" and this is used as a part of the lock name then (e.g. while calling lvm_vg_open()).
> When library user calls lvm_vg_close(), the original name "orphans_{lvm1, lvm2, pool}"
> is used directly and therefore no unlock occurs.
> 
> This simple patch adds possibility to exclude those internal VG names and ids in the
> lists provided by lvmcache: lvmcache_get_vgids() and lvmcache_get_vgnames().
> 
> (The actual problem we can observe now occurs while using udisks-lvm-pv-export that is
> called from udisks udev rule. This reserves the lock and prevents, for example, vgcreate
> to succeed...)
> 
> Peter
> 

Looks good Peter.  Reviewed line by line and tested.

Ack.