Generic partition creation interface.

This commit introduces a generic partition creation interface
which should be future-proof and extensible, and partially
replaces the old sfdisk-based interface.

The implementation is based on parted but is hopefully not too
dependent on the particulars of parted.

The following new calls are introduced:

  guestfs_part_init:
    Initialize a disk with a partition table.  Unlike the sfdisk-
    based interface, we also support GPT and other partition
    types, which is essential to scale to devices larger than 2TB.

  guestfs_part_add: Add a partition to an existing disk.

  guestfs_part_disk:
    Convenience function which combines part_init & part_add,
    creating a single partition that covers the whole disk.

  guestfs_part_set_bootable:
  guestfs_part_set_name:
    Set various aspects of existing partitions.

  guestfs_part_list:
    List partitions on a device.  This returns a programming-friendly
    list of partition structs (in contrast to sfdisk-l which cannot
    be parsed).

  guestfs_part_get_parttype:
    Return the partition table type, eg. "msdos" or "gpt".

The following calls are planned, but not added currently:

  guestfs_part_get_bootable
  guestfs_part_get_name
  guestfs_part_set_type
  guestfs_part_get_type

1 files changed, 13 insertions, 15 deletions

diff --git a/guestfs.pod b/guestfs.pod
index 33b84d73..fdac80a6 100644
--- a/guestfs.pod
+++ b/guestfs.pod
@@ -217,29 +217,27 @@ L<http://tldp.org/HOWTO/LVM-HOWTO/>.
 
 =head2 PARTITIONING
 
-To create MBR-style (ie. normal PC) partitions use one of the
-C<guestfs_sfdisk*> variants.  These calls use the external
-L<sfdisk(8)> command.
+In the common case where you want to create a single partition
+covering the whole disk, you should use the C<guestfs_part_disk>
+call:
 
-The simplest call is:
-
- char *lines[] = { ",", NULL };
- guestfs_sfdiskM (g, "/dev/sda", lines);
-
-This will create a single partition on C</dev/sda> called
-C</dev/sda1> covering the whole disk.
+ const char *parttype = "mbr";
+ if (disk_is_larger_than_2TB)
+   parttype = "gpt";
+ guestfs_part_disk (g, "/dev/sda", parttype);
 
 In general MBR partitions are both unnecessarily complicated and
 depend on archaic details, namely the Cylinder-Head-Sector (CHS)
-geometry of the disk.  C<guestfs_sfdiskM> allows you to specify sizes
-in megabytes instead of cylinders, which is a small win.
+geometry of the disk.  C<guestfs_sfdiskM> can be used to
+create more complex arrangements where the relative sizes are
+expressed in megabytes instead of cylinders, which is a small win.
 C<guestfs_sfdiskM> will choose the nearest cylinder to approximate the
 requested size.  There's a lot of crazy stuff to do with IDE and
 virtio disks having different, incompatible CHS geometries, that you
-probably don't want to know about.  My advice: make a single partition
-to cover the whole disk, then use LVM on top.
+probably don't want to know about.
 
-In future we aim to provide access to libparted.
+My advice: make a single partition to cover the whole disk, then use
+LVM on top.
 
 =head2 UPLOADING