Previously used "dmsetup info" to directly list device-mapper mapping
names in the kernel to identify active Logical Volumes. However GParted
failed to recognise active LVs if the VGNAME contains any hyphens (-).
This is because LVM encodes hyphens as double hyphens in the mapping
name.
To avoid having to duplicate the LVM hyphen encoding in GParted, switch
to using "lvm lvs" to list LVs.
# dmsetup info --columns --noheadings --separator , -o name
GParted_VG1-lvol_00
GParted--VG2-lvol--00
# lvm lvs --noheadings --separator , -o lv_name,vg_name,lv_attr
lvol_00,GParted_VG1,-wi-a-
lvol-00,GParted-VG2,-wi-a-
lvol-01,GParted-VG3,-wi---
.^.
(-) not active, (a) or any other character considered active. Reference
lvs(8).
Bug #160787 - lvm support
Previously when GParted was started LVM2_PV_Info cache was loaded twice,
executing LVM2 PV querying commands twice. Firstly when
lvm2_pv::get_filesystem_support() was checking if LVM2 PV support was
available, and secondly when forced by a refresh in
GParted_Core::set_devices().
Implement lazy initialization. Only load the cache when forced by the
above mentioned refresh or having to return a value when the cache is
not yet loaded. Do not initialize the cache when just checking if LVM2
PV support is available.
Bug #160787 - lvm support
Cache results from querying all LVM2 PVs in one go to minimise the
number of times lvm commands are executed. Take inspiration from
caching performed by FS_Info and Proc_Partitions_Info.
Bug #160787 - lvm support
Mike Fleetwood