The lvm query commands were always run and the cache loaded even if
GParted, actually blkid, didn't identify any LVM2 PVs. (GParted uses
libparted and blkid to identify partition content and the lvm commands
to provide the needed configuration details).
Now implement complete lazy initialization of the cache. Never force
loading of the cache. The cache is only loaded when the first value is
accessed from it. When there are no LVM2 PVs, the cache is never
queried, so never loaded. All the needed infrastructure for delayed
loading was previously added by this commit from 2011-12-11:
ff8ad04120
Lazy initialize the cache from querying LVM2 PVs (#160787)
Every public member function which access values from the cache already
calls initialize_if_required(). Just need to replace force loading of
the cache with a function which just clears the cache.
On my desktop, only when there are no LVM2 PVs, not loading the cache
and therefore not executing these external commands in
load_lvm2_pv_info_cache() saves 1.0 seconds of the 3.7 seconds it takes
to perform the a refresh in GParted:
lvm vgscan
lvm pvs ... -o pv_name,...
lvm pvs ... -o vg_name,...
Bug 750582 - Refactor the LVM2_PV_Info module object interface and
internal cache representation
GParted used to cache the results of the "lvm pvs" commands used to query
the state of the Logical Volume Manager as a series of lines of text.
Then every time a particular value was queried GParted would split all
the lines of text into fields until the required value was found.
Stop this repeat splitting of cached lines of text. Instead parse the
lines of text into separate fields and store in structures of values of
the correct type in the cache.
Bug 750582 - Refactor the LVM2_PV_Info module object interface and
internal cache representation
The LVM2_PV_Info cache had a pretend multi-object interface, yet all the
data is static. An LVM2_PV_Info object doesn't contain any member
variables, yet was needed just to call the member functions.
Make all the member functions static removing the need to use any
LVM2_PV_Info objects.
Bug 750582 - Refactor the LVM2_PV_Info module object interface and
internal cache representation
An LVM2_PV_Info object contains no member variables as all the data is
static (exists once in the program and accessed by all objects). The
constructor did nothing, except when passed true to load the cache.
Provide a separate load_cache() member function and remove the
constructors and destructor which do nothing. The C++ compiler will
provide a default constructor and destructor, which don't do anything as
there are no member variables to initialise and finalise.
This makes the interface a little easier to understand. Mostly a step
along the way of refactoring how the LVM2_PV_Info cache module works.
Bug 750582 - Refactor the LVM2_PV_Info module object interface and
internal cache representation
This is part of parent bug:
Bug #721455 - Obsolete info in license text on multiple modules
and GNOME Goal:
https://wiki.gnome.org/Initiatives/GnomeGoals/Proposals
* verify all source files to make sure they have a license and a
copyright, and that both are up-to-date
Bug #721565 - License text contains obsolete FSF postal address
Include guards need to be unique within GParted code and all included
library header files.
http://en.wikipedia.org/wiki/Include_guard#Difficulties
Use this model for all include guards:
#ifndef GPARTED_FILE_NAME_H
#define GPARTED_FILE_NAME_H
...
#endif /* GPARTED_FILE_NAME_H */
Closes Bug #539297 - Make include guards unique
Create common cache search and index functions get_attr_by_name() and
get_attr_by_row() as the existing ones, get_pv_attr_by_*() and
get_vg_attr_by_*(), only differ from each other by the string vector
they use.
If an LVM2 Volume Group has two or more missing Physical Volumes, the VG
is displayed as only having one "unknown device" because
get_vg_members() only adds unique names to the list of members.
# lvm pvcreate /dev/sda11 /dev/sda12 /dev/sda13
# lvm vgcreate Test-VG1 /dev/sda11 /dev/sda12 /dev/sda13
# wipefs -a /dev/sda12
# wipefs -a /dev/sda13
View partition information in GParted
The simplest fix would be to include the PV's UUID in the cache of LVM2
information and add PV names based on unique UUIDs being a member of the
relevant VG. Unfortunately "lvm pvs" seems to have a bug when
displaying Logical Volume attributes, and there are two or more missing
PVs, which causes one of the PVs to be displayed multiple times, rather
than displaying each PV once.
Without LV attributes, every PV is listed:
# lvm pvs --nosuffix --separator , --units b -o pv_name,pv_uuid,vg_name,vg_attr 2> /dev/null
PV,PV UUID,VG,Attr
/dev/sda11,pJ3R51-AOPP-rKlr-CKCT-nfPS-G5FP-B5Vyjm,Test-VG1,wz-pn-
unknown device,Y72oSm-uBcE-ktZL-OIFA-Q129-Uv1B-x5IsrA,Test-VG1,wz-pn-
unknown device,1ESORF-7wlR-0tnO-fy2z-nOL1-MrnJ-2O5yjK,Test-VG1,wz-pn-
With LV attributes, one missing PV is repeated:
# lvm pvs --nosuffix --separator , --units b -o pv_name,pv_uuid,vg_name,vg_attr,lv_name,lv_attr 2> /dev/null
PV,PV UUID,VG,Attr,LV,Attr
/dev/sda11,pJ3R51-AOPP-rKlr-CKCT-nfPS-G5FP-B5Vyjm,Test-VG1,wz-pn-,,
unknown device,Y72oSm-uBcE-ktZL-OIFA-Q129-Uv1B-x5IsrA,Test-VG1,wz-pn-,,
unknown device,Y72oSm-uBcE-ktZL-OIFA-Q129-Uv1B-x5IsrA,Test-VG1,wz-pn-,,
Also "lvm vgs" and "lvm lvs" don't display anything when including both
VG and LV attributes.
Instead query the LVM2 information in two separate commands, one
querying PV attributes and one querying VG and LV attributes, saving the
results in lvm_pv_cache and lvm_vg_cache respectively.
Bug #670171 - Add LVM PV read-write support
Add const qualifier to get_pv_attr_by_path() and get_pv_attr_by_row() as
they only access member variables read-only.
Make lvm2_pv_attr_to_num() a static member function as it doesn't access
any member variables.
Add reporting of the LVM2 Physical Volume size allowing the unallocated
space in the partition to be calculated.
Bug #499202 - gparted does not see the difference if partition size
differs from filesystem size
Also update to use LVM terminology, such that a Physical Volume is
referred to as a member of a Volume Group. Status of an LVM2 PV is now
displayed using one of the following messages:
Not active (Not a member of any volume group)
VGNAME not active
VGNAME not active and exported
VGNAME active
Bug #160787 - lvm support
GParted would crash if there were any embeded spaces in the output from
the command used to query LVM2 PVs. There aren't normally any embeded
spaces, but they can occur in certain degrated situations. For example
if one of the PVs in a VG spanning two PVs is lost the PV is displayed
as "unknown device" rather than its actual device name:
# lvm pvs --nosuffix --units b --separator , -o pv_name,pv_free,vg_name,lv_name,lv_attr
Couldn't find device with uuid DMEi8r-9Vvy-w0Ok-CSSn-oLmY-YrY3-1PBznz.
PV,PFree,VG,LV,Attr
/dev/sda11,2143289344,GParted-VG1,,
unknown device,1619001344,GParted-VG1,lvol0,-wi---
unknown device,1619001344,GParted-VG1,,
This was loaded into the cache as:
["/dev/sda11,2143289344,GParted-VG1,,",
"unknown",
"device,1619001344,GParted-VG1,lvol0,-wi---",
"unknown",
"device,1619001344,GParted-VG1,,"]
The crash would happen when trying to access the VG name or LV flags on
a line without enough comma separated fields.
Improve parsing of the output from "lvm pvs" so that lines are not split
on embeded spaces. Don't crash on lines without without enough comma
separated fields.
Bug #160787 - lvm support
Previously any errors which occurred when running LVM commands used to
load the LVM2_PV_Info cache were simply ignored and the cache wasn't
loaded. This lead to missing information about LVM2 PVs, but the user
had no indication as to why.
Now when any errors occur the command ran and all output is captured.
This is displayed to the user, along with a suitable warning message, in
the Partition Information dialog.
Bug #160787 - lvm support
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