blkdiscard: new command

Add to fstrim(8) code to support new discard BLKDISCARD and
BLKSECDISCARD ioctls for block devices.  The new command is only
symlink to fstrim(8) as the both utils share some code and the basic
ideas.

Based on patch from Lukas Czerner <lczerner@redhat.com>.

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: move partition types to label specific part

 - move MBR partition types to dos_part_types.h
 - make dos_part_types.h independent on datetypes to keep it useful in
   all fdisks
 - add struct fdisk_parrtype
 - move label specific partition types to context->label

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: improve list partition types

 - add fdisk_parttype->typestr for types like GPT UUID or Mac
 - list typestr if specified

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: add new functions for work with fdisk_parttype

 - add flags to fdisk_parttype to store more information about the types
 - function for conversion from code to fdisk_parttype
 - function for conversion from string to fdisk_parttype
 - function for conversion from user input to fdisk_parttype
 - support for unknown complex types (e.g. unknown UUIDs)

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: add fdisk_get_partition_type()

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: add fdisk_set_partition_type()

 - remove all label specific partition type stuff from fdisk.c to
   label files
 - add new fdisk_set_partition_type() to API

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: use fdisk_parttype  in add_partition

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: cleanup debug messages and comments

Signed-off-by: Karel Zak <kzak@redhat.com>
fdisk: add GPT support

This patch allows fdisk to handle GUID partition tables, based on the latest UEFI specifications
version 2.3.1, from June 27th, 2012. The following operations are supported:

  - Probing (detects both protective and hybrid MBRs)
  - Writing to disk
  - Listing used partitions
  - Adding partitions
  - Deleting partitions
  - Data integrity verifications (for both headers and partitions).

A few considerations:
  - Currently we do not fix invalid primary headers -- we just abort!
  - Header checksums are updated upon every change (ie: add/delete partitions), this allows us
    to mathematically verify the changes on-the-fly, and not only when writing to disk, like
    most other related tools do.
  - We are extremly picky when writing to disk, any error aborts the opeartion.
  - When creating a new partition, the following GUIDs are available:
     http://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs

For test cases, the gpt.img from libblkid tests, scsi_debug and my own hard drive (/dev/sda) were used.
For the image, all operations were tested successfully, and for /dev/sda all except write, which
was not tested - hey, I'm not suicidal!

[kzak@redhat.com: - add get/set partition type functions
                  - use unified on strings based table for partition types
                  - add partition type to table list function]

Tested-and-reviewed-by: Petr Uzel <petr.uzel@suse.cz>
Signed-off-by: Davidlohr Bueso <dave@gnu.org>
Signed-off-by: Karel Zak <kzak@redhat.com>
Revert "blkdiscard: new command"

This was only attempt as alternative implementation, unfortunately
pushed publicly... sorry.

This reverts commit c84ed54cefdcaa07f3d1f40a65434c9d4277da08.
blkdiscard: add new command

blkdiscard is used to discard device sectors. This is useful for
solid-state drivers (SSDs) and thinly-provisioned storage. Unlike
fstrim this command is used directly on the block device.

blkkdiscard uses BLKDISCARD ioctl or BLKSECDISCARD ioctl for the secure
discard.

All data in the discarded region on the device will be lost!

Signed-off-by: Lukas Czerner <lczerner@redhat.com>