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Mike Fleetwood 1382e0b828 Wait for udev change on /dev/DISK when querying whole device FS (!46)
GParted nearly always shows this warning against a whole disk device
FAT32 file system on my development VMs:
    plain floppy: device "/dev/sdb" busy (Resource temporarily
    unavailable): Cannot initialize '::'
    mlabel: Cannot initialize drive
However GParted does get the label via blkid instead.  Occasionally
everything works correctly and there is no warning.

Never found a similar error for any other file system on a whole disk
device.  The timing never seems to clash.

Remember that when a writable file descriptor of a disk device is
closed, udev events are triggered which update the kernel and /dev
entries for any partition changes.  (This is in addition to coding which
has always existed in the partitioning tools, including fdisk and
parted, to inform the kernel, but not create /dev entries, of partition
changes).

With debugging and sleeping in GParted, stracing the GParted thread
GParted_Core::set_devices_thread() and using 'udevadm monitor' to watch
udev events the following sequence of events is observed:

  gparted    |set_devices_thread(pdevices)  pdevices->["/dev/sdb"]
  gparted    |  ped_device_get("/dev/sdb")
  libparted  |      open("/dev/sdb", O_RDONLY) = 8
  libparted  |      close(8)
  gparted    |  useable_device(lp_device)  lp_device->path="/dev/sdb"
  gparted    |    ped_device_open()
  libparted  |      open("/dev/sdb", O_RDWR) = 8
  gparted    |    ped_device_read()
  gparted    |    ped_device_close()
  libparted  |      close(8)
  udev(async)|        KERNEL change /devices/.../sdb (block)
  udev(async)|        KERNEL change /devices/.../sdb (block)
  udev(async)|        UDEV   change /devices/.../sdb (block)
  udev(async)|        UDEV   change /devices/.../sdb (block)
  gparted    |  set_device_from_disk(device, device_path="/dev/sdb")
  gparted    |    get_device(device_path="/dev/sdb", ..., flush=true)
  gparted    |      ped_device_get()
  gparted    |      flush_device(lp_device)  lp_device->path="/dev/sdb"
  gparted    |        ped_device_open()
  libparted  |          open("/dev/sdb", O_RDWR) = 8
  gparted    |        ped_device_sync()
  gparted    |        ped_device_close()
  libparted  |          close(8)
  udev(async)|            KERNEL change /devices/.../sdb (block)
  udev(async)|            KERNEL change /devices/.../sdb (block)
  udev(async)|            UDEV   change /devices/.../sdb (block)
  udev(async)|            UDEV   change /devices/.../sdb (block)
  gparted    |    set_device_one_partition()
  gparted    |      set_partition_label_and_uuid()
  gparted    |        read_label()
  gparted    |          fat16::read_label()
  gparted    |            Utils::execute_command("mlabel -s :: -i /dev/sdb")

This sequence of events only shows which close()s by libparted trigger
udev events.  It does not show that processing those events are
asynchronous and overlap with GParted executing mlabel, causing the
device busy error.

As libparted's ped_device_open() doesn't offer a way to specify that a
device will only be used for reading, it always opens it read-write
[1][2].  Hence this sequence in GParted_Core::flush_device():
    ped_device_open()
    ped_device_sync()
    ped_device_close()
always triggers udev change events on the whole disk device.  Fix by
waiting for those udev events to complete.

[1] libparted documentation, PedDevice, ped_device_open()
    https://www.gnu.org/software/parted/api/group__PedDevice.html#ga7c87bd06e76553c8ff3262b5e6ca256

[2] parted/libparted/arch/linux.c:linux_open()
    http://git.savannah.gnu.org/cgit/parted.git/tree/libparted/arch/linux.c?id=v3.2#n1628

Closes !46 - Whole device FAT32 file system reports device busy warning
             from mlabel
2019-07-18 15:27:43 +00:00
data Increase minimum required gtkmm to 2.11.1 (#794253) 2018-03-26 10:16:45 -06:00
doc Update URLs in the remaining files to https://gparted.org (#796411) 2018-06-19 09:47:19 -06:00
help Fix link typo in French translation of GParted help manual 2019-05-29 11:36:03 -06:00
include Drop use of long ago removed udevinfo 2019-07-04 10:51:50 -06:00
lib Update to Google Test 1.8.1 2019-01-21 16:41:31 +00:00
m4 Update Autoconf macro AX_CXX_COMPILE_STDCXX_11 to latest serial 18 2018-08-01 19:03:01 +01:00
po Update Brazilian Portuguese translation 2019-07-18 13:06:48 +00:00
src Wait for udev change on /dev/DISK when querying whole device FS (!46) 2019-07-18 15:27:43 +00:00
tests Fix test (dentry->d_name is invalidated by closedir...) (!41) 2019-05-31 19:32:52 +01:00
.gitignore Add use of new GNOME 3 yelp-tools documentation infrastructure (!24) 2019-03-01 16:46:56 +00:00
.gitlab-ci.yml Drop now unnecessary editing of xmllint command line in CI tests (!24) 2019-03-01 16:46:56 +00:00
AUTHORS Update copyright years 2019-05-29 09:46:10 -06:00
COPYING Revert "Fixed FSF's address. Fixes #721565" 2014-01-31 14:39:20 +01:00
COPYING-DOCS Added COPYING-DOCS and removed help/C/legal.xml file. The GFDL license should be translated only once per language, and not for each and every project that uses the license. See GParted bug #550047 2008-09-01 17:01:14 +00:00
ChangeLog Correctly capitalise GNOME in the Manual and man page (#739805) 2014-12-20 10:02:55 -07:00
HACKING Add translatable files reminder to HACKING file 2016-12-02 10:06:09 -07:00
Makefile.am Drop compose subdir (#46) 2019-03-27 16:45:22 +00:00
NEWS ========== gparted-1.0.0 ========== 2019-05-29 09:54:20 -06:00
README Update distro specific package installation instructions 2019-04-03 20:45:31 +00:00
autogen.sh Remove deprecated PKG_NAME from autogen.sh 2019-03-01 16:46:56 +00:00
configure.ac Append -git to version for continuing development 2019-05-29 10:21:07 -06:00
gparted.appdata.xml.in Update GParted appdata file (#12) 2018-10-08 09:53:58 -06:00
gparted.desktop.in.in Now install gparted wrapper script into $prefix/bin (#776437) 2017-09-01 10:14:20 -06:00
gparted.doap Update bug links from Bugzilla to GitLab issues (!11) 2018-08-24 09:54:12 +01:00
gparted.in Remove support for obsolete devkit-disks automount inhibitor 2018-06-27 20:26:40 +00:00
logo.png Add logo.png for automatic GitLab/GitHub project avatar 2018-05-25 17:18:49 +01:00
org.gnome.gparted.policy.in.in Update URLs in the remaining files to https://gparted.org (#796411) 2018-06-19 09:47:19 -06:00
testbuild.sh Add testbuild.sh script (#699881) 2013-05-27 11:08:39 -06:00

README

GPARTED
=======
Gparted is the GNOME Partition Editor for creating, reorganizing, and
deleting disk partitions.

A hard disk is usually subdivided into one or more partitions.  These
partitions are normally not re-sizable (making one smaller and the
adjacent one larger.)  Gparted makes it possible for you to take a
hard disk and change the partition organization, while preserving the
partition contents.

More specifically, Gparted enables you to create, destroy, resize,
move, check, label, and copy partitions, and the file systems
contained within.  This is useful for creating space for new operating
systems, reorganizing disk usage, and mirroring one partition with
another (disk imaging).

Gparted can also be used with storage devices other than hard disks,
such as USB flash drives, and memory cards.

Visit https://gparted.org for more information.


LICENSING
---------
GParted is released under the General Public License version 2, or (at
your option) any later version.  (GPLv2+).  All files are released under
the GPLv2+ unless explicitly licensed otherwise.

The GParted Manual is released under the GNU Free Documentation License
version 1.2 or any later version.  (GFDLv1.2+).

Google Test C++ test framework is released under the 3-Clause BSD
License.  (BSD-3-Clause).

See these files for more details:
   COPYING      - GNU General Public License version 2
   COPYING-DOCS - GNU Free Documentation License version 1.2
   lib/gtest/LICENSE
                - 3-Clause BSD License


NEWS
----
Information about changes to this release, and past releases can be
found in the file:
   NEWS


INSTALL
-------
a. Pre-built Binary

   Many GNU/Linux distributions already provide a pre-built binary
   package for GParted.  Instructions on how to install GParted on
   some distributions is given below:

      CentOS/RHEL
      -----------
      su -
      yum install gparted

      Debian or Ubuntu
      ----------------
      sudo apt-get install gparted

      Fedora
      ------
      su -
      dnf install gparted

      OpenSUSE
      --------
      sudo zypper install gparted

b. Building from Source

   Briefly, build and install GParted into the default location of
   /usr/local using:
      ./configure
      make
      sudo make install
      sudo install -m 644 org.gnome.gparted.policy \
             /usr/share/polkit-1/actions/org.gnome.gparted.local.policy
   This assumes all the dependencies are already installed, builds the
   default configuration and polkit is being used as the graphical su
   program.

   The following dependencies are required to build GParted from source:
      g++
      make
      parted
      gnome-common
      gtkmm3
      gettext
      intltool
      yelp-tools          - required if help documentation is to be built

   On CentOS/RHEL, these dependencies may be obtained by running the
   following command as root:
      yum install gnome-common yelp-tools glib2-devel intltool gcc-c++ \
                  libuuid-devel parted-devel gtkmm30-devel make

   On Debian or Ubuntu, these dependencies may be obtained by running
   one of the following commands:
     Either;
      sudo apt-get build-dep gparted
     Or;
      sudo apt-get install build-essential gnome-common yelp-tools \
                           libglib2.0-dev uuid-dev libparted-dev \
                           libgtkmm-3.0-dev

   On Fedora, these dependencies may be obtained by running the
   following command as root:
      dnf install gnome-common yelp-tools glib2-devel intltool gcc-c++ \
                  parted-devel gtkmm30-devel make

   On openSUSE, these dependencies may be obtained by running the
   following commands:
      sudo zypper install gnome-common gcc-c++ libuuid-devel \
                          parted-devel gtkmm3-devel make

   Again, build GParted with the default configuration and install into
   the default location of /usr/local using:
      ./configure
      make
      sudo make install

   If you wish to build this package without the help documentation use
   the --disable-doc flag:
      E.g., ./configure --disable-doc

   If you wish to build this package to use native libparted /dev/mapper
   dmraid support use the --enable-libparted-dmraid flag:
      E.g., ./configure --enable-libparted-dmraid

   If you wish to build this package with online resize support then
   the following is required:
      a)  Linux kernel version 3.6 or higher.
      b)  Libparted with online resize support.  Either:
          i)  Libparted version 3.2 or later which includes online
              resize support as standard.  In this case GParted is
              automatically built with online resize support.
          ii) Online resize support back ported into an earlier version
              of libparted.  This is only known to be included in Debian
              and derived distributions with parted version 2.3-14 and
              higher.  In this case online resize support must be
              specifically enabled with the --enable-online-resize flag:
                E.g., ./configure --enable-online-resize

   If you wish to build GParted to allow it to use xhost to grant root
   access to the X11 server use the --enable-xhost-root flag.  This is
   required to allow GParted to display under Wayland.
      ./configure --enable-xhost-root

   Please note that more than one configure flag can be used:
      E.g., ./configure --disable-doc --enable-libparted-dmraid

   The INSTALL file contains further GNU installation instructions.

c. Installing polkit's Action File

   GParted needs to run as root therefore it needs a graphical switch
   user program to allow normal users to run it.  Most desktops now use
   polkit as their preferred authorisation mechanism.  Therefore
   ./configure looks for polkit's pkexec as the first choice with
   fallbacks in order being: gksudo, gksu, kdesudo and finally xdg-su.
   Also polkit reads action files only from directory
   /usr/share/polkit-1/actions.  Therefore it is likely that a polkit
   action file will need to be installed into this directory.

   To determine if polkit's pkexec program is being used as the
   graphical privilege escalation program examine the output from
   ./configure.  These lines report that pkexec is being used:

      checking for pkexec >= 0.102... 0.112 found

   Where as either of these lines of ./configure output report that
   pkexec is not being used because either it was too old a version or
   it was not found:

      checking for pkexec >= 0.102... 0.96 found

      checking for pkexec >= 0.102... not found

   When GParted is configured with prefix /usr (using command
   ./configure --prefix=/usr) then make install will automatically
   install the polkit action file into the correct directory and no
   further steps need to be taken.  This is typically the case for
   distribution builds of GParted.

   However when GParted is configured with the default prefix of
   /usr/local, or any prefix other than /usr, then the polkit action
   file has to be manually installed into the correct directory.  Also
   it should have a unique file name to avoid overwriting the action
   file from the distribution's package.  Install the polkit action file
   with a unique name including an extra ".local" in the name:

      sudo install -m 644 org.gnome.gparted.policy \
             /usr/share/polkit-1/actions/org.gnome.gparted.local.policy

d. Building using a Specific (lib)parted Version

   1) Download the parted version you wish to use (e.g., 3.2) from:

      http://ftp.gnu.org/gnu/parted/

   2) Build and install parted.

      Extract parted tarball, configure, make, and sudo make install.
      Note that by default this will install into /usr/local.

   3) Set environment variables to inform the GParted build system to
      use libparted from /usr/local:

        export CPPFLAGS=-I/usr/local/include
        export LDFLAGS=-L/usr/local/lib
        export LD_RUN_PATH=/usr/local/lib
        export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

   4) Build gparted using steps listed above in "Building from Source".

      Note that when you run ./configure you should see the specific
      version of parted listed in the check for libparted >= 1.7.1.

      You will also see the libparted version listed when running
      gparted from the command line.


DIRECTORIES
------------
data     - contains desktop icons

doc      - contains manual page documentation

help     - contains GParted Manual and international translations

include  - contains source header files

lib/gtest
         - contains Google Test C++ test framework libraries

m4       - contains macro files

po       - contains international language translations

src      - contains C++ source code


DISTRIBUTION NOTES
------------------
GParted uses GNU libparted to detect and manipulate devices and
partition tables.  The blkid command is also required to detect those
file systems which libparted doesn't detect.  (The blkid command should
be considered a mandatory requirement).

GParted also queries and manipulates the file systems within those
devices and partitions.  When available, it uses each file system's
specific commands.  The following optional file system specific packages
provide this support:

   btrfs-progs / btrfs-tools
   e2fsprogs
   f2fs-tools
   dosfstools
   mtools          - required to read and write FAT16/32 volume labels
                     and UUIDs
   hfsutils
   hfsprogs
   jfsutils
   nilfs-utils
   ntfs-3g / ntfsprogs
   reiser4progs
   reiserfsprogs / reiserfs-utils / reiserfs
   udftools
   util-linux      - required to create and check MINIX file systems
   xfsprogs, xfsdump


For dmraid support, the following packages are required:

   dmsetup         - removes /dev/mapper entries
   dmraid          - lists dmraid devices and creates /dev/mapper
                     entries

For GNU/Linux distribution dmraid support, the following are required:
   - kernel built with Device Mapping and Mirroring built.  From
     menuconfig, it is under Device Drivers -> <something> (RAID & LVM).
   - dmraid drive arrays activated on boot (e.g., dmraid -ay).


For LVM2 Physical Volume support the following command is required:
   lvm             - LVM2 administration tool
And device-mapper support in the kernel.


For accurate detection and reporting of Linux Software RAID Arrays the
following command is required:

   mdadm           - SWRaid administration tool


For LUKS support the following commands are required:
   cryptsetup      - LUKS volume administration tool
   dmsetup         - Device-mapper administration tool


For attempt data rescue for lost partitions, the following package
is required:
   gpart           - guesses PC-type hard disk partitions


Several more commands are optionally used by GParted if found on the
system.  These commands include:

   blkid           - [mandatory requirement] used to detect file systems
                     libparted doesn't, read UUIDs and volume labels
   hdparm          - used to query disk device serial numbers
   udisks          - used to prevent automounting of file systems
   devkit-disks    - used to prevent automounting of file systems
   {filemanager}   - used in attempt data rescue to display discovered
                     file systems.  (e.g., nautilus, pcmanfm)
   hal-lock        - used to prevent automounting of file systems
   pkexec          - used to acquire root privileges in gparted shell
                     script wrapper, but only if available when gparted
                     source is configured
   gksudo          - alternatively used to acquire root privileges in
                     gparted shell script wrapper, second choice if
                     available when gparted source is configured
   gksu            - alternatively used to acquire root privileges in
                     gparted shell script wrapper, third choice if
                     available when gparted source is configured
   kdesudo         - alternatively used to acquire root privileges in
                     gparted shell script wrapper, fourth choice if
                     available when gparted source is configured
   xdg-su          - alternatively used to acquire root privileges in
                     gparted shell script wrapper, last choice if
                     available when gparted source is configured
   udevinfo        - used in dmraid to query udev name
   udevadm         - used in dmraid to query udev name
   yelp            - used to display help manual
   xhost           - used to grant root access to the X11 server, only
                     when configured to do so