The comment became completely unnecessary with the transfer of
mount_info and fstab_info into separate Mount_Info module by commit:
63ec73dfda
Split mount_info and fstab_info maps into separate Mount_Info module
It was never necessary to clear one of the mappings at the end of the
device refresh because it was reloaded at the start of the next device
refresh anyway and it is only a small amount of memory.
Have an unmounted file system within an open encrypted mapping and an
entry in /etc/fstab for the file system like this:
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
...
sdb 8:16 0 8G 0 disk
+-sdb1 8:17 0 1G 0 part
+-sdb1_crypt 253:0 0 1022M 0 crypt
# blkid | grep sdb1
/dev/sdb1: TYPE="crypto_LUKS" ...
/dev/mapper/sdb1_crypt: TYPE="ext4" ...
# ls -l /dev/mapper/sdb1_crypt /dev/dm-0
brw-rw----. 1 root disk 253, 0 Sep 12 19:09 /dev/dm-0
lrwxrwxrwx. 1 root root 7 Sep 12 19:09 /dev/mapper/sdb1_crypt -> ../dm-0
# grep sdb1 /etc/fstab
/dev/mapper/sdb1_crypt /mnt/1 ext4 defaults 0 0
The mount point will be shown twice for the partition:
/mnt/1, /mnt/1
This is because add_node_and_mountpoint() adds two entries for both the
symbolic and real block special names:
map["/dev/mapper/sdb1_crypt"] = ["/mnt/1"]
map["/dev/dm-0"] = ["/mnt/1"]
This was needed for the old code which used string compare to match
block devices so that the mount point could be looked up by either name.
However since bug 767842 introduced major, minor number comparison it
became unnecessary. As both names refer to the same device the mount
point gets added twice to the same entry. Hence display of the double
mount.
map[BlockSpecial{"/dev/mapper/sdb1_crypt", 253, 0}] =
["/mnt/1", "/mnt/1"]
It is always going to be the case that the symbolic link and real block
special names have the same major, minor numbers. That was the
requirement of the BlockSpecial class and the reason for using stat() to
lookup the numbers. Therefore adding entries for both names will always
add duplicate entries. Fix by stop using realpath() to lookup the real
name and adding the duplicate entry.
Introduced by:
a800ca8b68
Add BlockSpecial into mount_info and fstab_info (#767842)
Bug 771323 - GParted is showing duplicate mount points for unmounted
encrypted file systems
The GParted_Core::mount_info and GParted_Core::fstab_info maps and the
methods that manipulate them are self-contained. Therefore move them to
a separate Mount_Info module and reduce the size of the monster
GParted_Core slightly.
The FS_Info module has a pseudo multi-object interface and used the
constructor to load the cache. However all the data in the class is
static. An FS_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
FS_Info objects and provide an explicit load_cache() method.
Following earlier commit "Pre-populate BlockSpecial cache while reading
/proc/partitions (#767842)" load_proc_partitions_info_cache() has
extracted just the name field from each line of /proc/partitions.
Therefore simplify the regular expressions matching each type of whole
disk device to just matching in the name field rather than matching in
the whole line.
The Proc_Partitions_Info has a pseudo multi-object interface and uses
the constructor to load the cache. However all the data in the class is
static. A Proc_Partitions_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
Proc_Partitions_Info objects and provide and explicit load_cache()
method.
Vol_id has been retired and removed from all supported distributions.
See earlier commit "Remove use of retired vol_id from FS_Info module
(#767842)" for more details. Therefore remove it's use from GParted
entirely.
GParted is already reading /proc/partitions to get whole disk device
names. The file also contains the major, minor device number of every
partition. Use this information to pre-populate the cache in the
BlockSpecial class.
# cat /proc/partitions
major minor #blocks name
8 0 20971520 sda
8 1 512000 sda1
8 2 20458496 sda2
...
9 3 1047552 md3
259 2 262144 md3p1
259 3 262144 md3p2
...
253 0 18317312 dm-0
253 1 2097152 dm-1
253 2 8383872 dm-2
253 3 1048576 dm-3
Note that for Device-Mapper names (dm-*) the kernel is not using the
canonical user space names (mapper/*). There is no harm in
pre-populating the cache with these names and will help if tools report
them too. It is just that for DMRaid, LVM and LUKS, GParted uses the
canonical /dev/mapper/* names so will still have to call stat() once for
each such name.
For plain disks (sd*) and Linux Software RAID arrays (md*) the kernel
name is the common user space name too, therefore matches what GParted
uses and pre-populating does avoid calling stat() at all for these
names.
Bug 767842 - File system usage missing when tools report alternate block
device names
Creation of every BlockSpecial object used to result in a stat() OS
call. On one of my test VMs debugging with 4 disks and a few partitions
on each, GParted refresh generated 541 calls to stat() in the
BlockSpecial(name) constructor. However there were only 45 unique
names. So on average each name was stat()ed approximately 12 times.
Cache the major, minor number associated with each name after starting
with a cleared cache for each GParted refresh. This reduces these
direct calls to stat() to just the 45 unique names.
Bug 767842 - File system usage missing when tools report alternate block
device names
The FS_Info cache is loaded from "blkid" output and compares block
special names. Therefore switch to using BlockSpecial objects so that
comparisons are performed by the major, minor device number instead.
Bug 767842 - File system usage missing when tools report alternate block
device names
FS_Info module caches the output from blkid as a single string and uses
regular expressions to find the line matching the requested block
special file name. This is not compatible with using BlockSpecial
objects to represent block special files, and perform matching by major,
minor device number. Therefore parse the blkid output into a vector of
structures containing the needed fields, ready for switching to
BlockSpecial objects in the following patch.
Interface to the module remains unchanged.
Bug 767842 - File system usage missing when tools report alternate block
device names
Vol_id was removed from udev 142, released 2009-05-13, and udev switched
to using blkid instead [1]. All currently supported distributions use
later versions of udev (or systemd after the udev merge), except for
RedHat / CentOS 5 with udev 095. However RedHat / CentOS 5 does provide
blkid and vol_id is found in udev specific /lib/udev directory not on
the PATH. Therefore effectively vol_id is not available on any
supported distribution and blkid is always available. Therefore remove
use of vol_id from the FS_Info module. Less code to refactor and test
in following changes.
[1] delete vol_id and require util-linux-ng's blkid
http://git.kernel.org/cgit/linux/hotplug/udev.git/commit/?id=f07996885dab45102492d7f16e7e2997e264c725
Bug 767842 - File system usage missing when tools report alternate block
device names
The SWRaid_Info cache is loaded from "mdadm" command output and
/proc/mdstat file. It contains the member name which is used to access
the cache, therefore switch to using BlockSpecial objects so that
comparison is performed using the major, minor device number.
Bug 767842 - File system usage missing when tools report alternate block
device names
The LUKS_Info module cache is loaded from "dmsetup" command and compares
block special files, therefore switch to using BlockSpecial objects so
that comparisons are performed by major, minor device number.
Bug 767842 - File system usage missing when tools report alternate block
device names
Small optimisation which avoids constructing an extra BlockSpecial
object when determining if a btrfs member is mounted. Rather than
extracting the name from the BlockSpecial object in
btrfs::get_mount_device() and re-constructing another BlockSpecial
object from that name in GParted_Core::is_dev_mounted(), pass the
BlockSpecial object directly.
Bug 767842 - File system usage missing when tools report alternate block
device names
There are no known errors which affect the remaining caches in GParted.
However those caches which compare block special devices will be changed
to use BlockSpecial objects so comparison is by major, minor device
number rather than by name.
Change btrfs member cache loaded from "btrfs filesystem show" output to
use BlockSpecial objects.
Bug 767842 - File system usage missing when tools report alternate block
device names
On some distributions having btrfs on top of LUKS encrypted partitions,
adding a second device and removing the first device used to mount the
file system causes GParted to no longer be able to report the file
system as busy or the mount points themselves.
For example, on CentOS 7, create a single btrfs file system and mount
it. The provided /dev/mapper/sdb1_crypt name is reported, via
/proc/mounts, as the mounting device:
# cryptsetup luksFormat --force-password /dev/sdb1
# cryptsetup luksOpen /dev/sdb1 sdb1_crypt
# mkfs.btrfs -L encrypted-btrfs /dev/mapper/sdb1_crypt
# mount /dev/mapper/sdb1_crypt /mnt/1
# ls -l /dev/mapper
total 0
lrwxrwxrwx. 1 root root 7 Jul 2 14:15 centos-root -> ../dm-1
lrwxrwxrwx. 1 root root 7 Jul 2 14:15 centos-swap -> ../dm-0
crw-------. 1 root root 10, 236 Jul 2 14:15 control
lrwxrwxrwx. 1 root root 7 Jul 2 15:14 sdb1_crypt -> ../dm-2
# fgrep btrfs /proc/mounts
/dev/mapper/sdb1_crypt /mnt/1 btrfs rw,seclabel,relatime,space_cache 0 0
Add a second device to the btrfs file system:
# cryptsetup luksFormat --force-password /dev/sdb2
# cryptsetup luksOpen /dev/sdb2 sdb2_crypt
# btrfs device add /dev/mapper/sdb2_crypt /mnt/1
# ls -l /dev/mapper
...
lrwxrwxrwx. 1 root root 7 Jul 2 15:12 sdb2_crypt -> ../dm-3
# btrfs filesystem show /dev/mapper/sdb1_crypt
Label: 'encrypted-btrfs' uuid: 45d7b1ef-820c-4ef8-8abd-c70d928afb49
Total devices 2 FS bytes used 32.00KiB
devid 1 size 1022.00MiB used 12.00MiB path /dev/mapper/sdb1_crypt
devid 2 size 1022.00MiB used 0.00B path /dev/mapper/sdb2_crypt
Remove the first mounting device from the btrfs file system. Now the
non-canonical name /dev/dm-3 is reported, via /proc/mounts, as the
mounting device:
# btrfs device delete /dev/mapper/sdb1_crypt /mnt/1
# btrfs filesystem show /dev/mapper/sdb2_crypt
Label: 'encrypted-btrfs' uuid: 45d7b1ef-820c-4ef8-8abd-c70d928afb49
Total devices 1 FS bytes used 96.00KiB
devid 2 size 1022.00MiB used 144.00MiB path /dev/mapper/sdb2_crypt
# fgrep btrfs /proc/mounts
/dev/dm-3 /mnt/1 btrfs rw,seclabel,relatime,space_cache 0 0
# ls -l /dev/dm-3
brw-rw----. 1 root disk 253, 3 Jul 2 15:12 /dev/dm-3
GParted loads the mount_info mapping from /proc/mounts and with it the
/dev/dm-3 name. When GParted is determining if the encrypted btrfs file
system is mounted or getting the mount points it is using the
/dev/mapper/sdb2_crypt name. Therefore no information is found and the
file system is incorrectly reported as unmounted.
Fix by changing mount_info and fstab_info to use BlockSpecial objects
instead of strings so that matching is performed by major, minor device
numbers rather than by string compare. Note that as BlockSpecial
objects are used as the key of std::map [1] mappings operator<() [2]
needs to be provided to order the key values.
[1] std::map
http://www.cplusplus.com/reference/map/map/
[2] std::map::key_comp
http://www.cplusplus.com/reference/map/map/key_comp/
Bug 767842 - File system usage missing when tools report alternate block
device names
In some cases creating an LVM2 Physical Volume on top of a DMRaid array
reports no usage information and this partition warning:
Unable to read the contents of this file system!
Because of this some operations may be unavailable.
The cause might be a missing software package.
The following list of software packages is required for lvm2
pv file system support: lvm2.
For example on Ubuntu 14.04 LTS (with GParted built with
--enable-libparted-dmraid) create an LVM2 PV in a DMRaid array
partition. GParted uses this command:
# lvm pvcreate -M 2 /dev/mapper/isw_bacdehijbd_MyArray0p2
But LVM reports the PV having a different name:
# lvm pvs
PV VG Fmt Attr PSize PFree
/dev/disk/by-id/dm-name-isw_bacdehijbd_MyArray0p2 lvm2 a-- 1.00g 1.00g
This alternate name is loaded into the LVM2_PV_Info module cache. Hence
when GParted queries partition /dev/mapper/isw_bacdehijbd_MyArray0p2 it
has no PV information against that name and reports unknown usage.
However they are actually the same block special device; major 252,
minor 2:
# ls -l /dev/mapper/isw_bacdehijbd_MyArray0p2
brw-rw---- 1 root disk 252, 2 Jul 2 11:09 /dev/mapper/isw_bacdehijbd_MyArray0p2
# ls -l /dev/disk/by-id/dm-name-isw_bacdehijbd_MyArray0p2
lrwxrwxrwx 1 root root 10 Jul 2 11:09 /dev/disk/by-id/dm-name-isw_bacdehijbd_MyArray0p2 -> ../../dm-2
# ls -l /dev/dm-2
brw-rw---- 1 root disk 252, 2 Jul 2 11:09 /dev/dm-2
To determine if two names refer to the same block special device their
major, minor numbers need to be compared, instead of string comparing
their names.
Implement class BlockSpecial which encapsulates the name and major,
minor numbers for a block special device. Also performs comparison as
needed. See bug 767842 comments 4 and 5 for further investigation and
decision for choosing to implement a class.
Replace name strings in the LVM2_PV_Info module with BlockSpecial
objects performing correct block special device comparison.
Bug 767842 - File system usage missing when tools report alternate block
device names
Now Device and Partition objects only have a single path,
get_alternate_paths() is never called. Remove the method and population
of the private alternate_paths_cache member that went with it.
Bug 767842 - File system usage missing when tools report alternate block
device names
To reflect that there is now only a single path in the Partition object
now. Also get rid of the now unneeded optional clear_paths parameter
which was only relevant when there was a vector of paths.
Bug 767842 - File system usage missing when tools report alternate block
device names
Now that Partition objects only have a single path, rather than a list
of paths, stop performing unnecessary actions in calibrate_partitions()
which added alternate paths reported from libparted. Just left with
setting the partition path name correctly, when the path name doesn't
exist. Happens when the path is set to "Copy of /dev/SRC" when the
partition was newly created by a copy-paste into unallocated space
earlier in the sequence of operations now being applied.
Bug 767842 - File system usage missing when tools report alternate block
device names
Change from a vector of paths to a single path member in the Partition
object. Remove add_paths() and get_paths() methods. Keep add_path()
and get_path().
Bug 767842 - File system usage missing when tools report alternate block
device names
To reflect that there is only a single path in the Device object now.
Also get rid of the now unneeded optional parameter which was only
relevant when there was a vector of paths.
Bug 767842 - File system usage missing when tools report alternate block
device names
Background
GParted stored a list of paths for Device and Partition objects. It
sorted this list [1][2] and treated the first specially as that is what
get_path() returned and was used almost everywhere; with the file system
specific tools, looked up in various *_Info caches, etc.
[1] Device::add_path(), ::add_paths()
[2] Partition::add_path(), ::add_paths()
Mount point display [3] was the only bit of GParted which really worked
with the path list. Busy file system detection [4] just used the path
provided by libparted, or for LUKS /dev/mapper/* names. It checked that
single path against the mounted file systems found from /proc/mounts,
expanded with additional block device names when symlinks were
encountered.
[3] GParted_Core::set_mountpoints() -> set_mountpoints_helper()
[4] GParted_Core::set_device_partitions() -> is_busy()
GParted_Core::set_device_one_partition() -> is_busy()
GParted_Core::set_luks_partition() -> is_busy()
Having the first path, by sort order, treated specially by being used
everywhere and virtually ignoring the others was wrong, complicated to
remember and difficult code with. As all the additional paths were
virtually unused and made no difference, remove them. The "improved
detection of mountpoins, free space, etc.." benefit from commit [5]
doesn't seem to exist. Therefore simplify to a single path for Device
and Partition objects.
[5] commit 6d8b169e73
changed the way devices and partitions store their device paths.
Instead of holding a 'realpath' and a symbolic path we store paths
in a list. This allows for improved detection of mountpoins, free
space, etc..
This patch
Simplify the Device object from a vector of paths to a single path.
Remove add_paths() and get_paths() methods. Keep add_path() and
get_path() for now.
Bug 767842 - File system usage missing when tools report alternate block
device names
Recognise GRUB2 core.img boot code written to a partition without a file
system. Such setups are possible/likely with GPT partitioned disks as
there is a specific partition type reserved for it [1][2]:
21686148-6449-6E6F-744E-656564454649 (BIOS Boot partition)
[1] GUID Partition Table, Partition types
https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs
[2] BIOS boot partition
https://en.wikipedia.org/wiki/BIOS_boot_partition
Bug 766989 - zfsonline support - need file system name support for ZFS
type codes
