How do you increase a KVM guest's disk space?

How do you go about increasing KVM virtual machine guest's disk space from the command line if you initially set insufficient amount of disk space?

1. Shutdown the VM
2. Move the current image
   
mv mykvm.img mykvm.img.bak
3. Create a new image
   
qemu-img create -f raw addon.raw 30G
4. concatenate the 2 images
   
cat mykvm.img.bak addon.raw >> mykvm.img
5. start the VM (using the newly created mykvm.img)
6. run fdisk inside VM and delete & re-create LVM partition
   % fdisk /dev/vda
   ...
   Device Boot Start End Blocks Id System
   /dev/vda1 * 1 13 104391 83 Linux
   /dev/vda2 14 3263 26105625 8e Linux LVM

   Command (m for help): d
   Partition number (1-4): 2

   Command (m for help): p

   Disk /dev/vda: 48.3 GB, 48318382080 bytes
   255 heads, 63 sectors/track, 5874 cylinders
   Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot Start End Blocks Id System
   /dev/vda1 * 1 13 104391 83 Linux

   Command (m for help): n
   Command action
   e extended
   p primary partition (1-4)
   p
   Partition number (1-4): 2
   First cylinder (14-5874, default 14): 14
   Last cylinder or +size or +sizeM or +sizeK (14-5874, default 5874):
   Using default value 5874

   Command (m for help): p

   Disk /dev/vda: 48.3 GB, 48318382080 bytes
   255 heads, 63 sectors/track, 5874 cylinders
   Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot Start End Blocks Id System
   /dev/vda1 * 1 13 104391 83 Linux
   /dev/vda2 14 5874 47078482+ 83 Linux

   Command (m for help): t
   Partition number (1-4): 2
   Hex code (type L to list codes): 8e
   Changed system type of partition 2 to 8e (Linux LVM)

   Command (m for help): p

   Disk /dev/vda: 48.3 GB, 48318382080 bytes
   255 heads, 63 sectors/track, 5874 cylinders
   Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot Start End Blocks Id System
   /dev/vda1 * 1 13 104391 83 Linux
   /dev/vda2 14 5874 47078482+ 8e Linux LVM

   Command (m for help): w
   The partition table has been altered!

   Calling ioctl() to re-read partition table.

   WARNING: Re-reading the partition table failed with error 16: Device or
   resource busy.
   The kernel still uses the old table.
   The new table will be used at the next reboot.
   Syncing disks.
   %

7. Reboot the VM
8. Resize the LVM physical volume
   % pvdisplay
   --- Physical volume ---
   PV Name /dev/vda2
   VG Name VolGroup00
   PV Size 24.90 GB / not usable 21.59 MB
   Allocatable yes (but full)
   PE Size (KByte) 32768
   Total PE 796
   Free PE 0
   ...

   % pvresize /dev/vda2

   % pvdisplay
   --- Physical volume ---
   PV Name /dev/vda2
   VG Name VolGroup00
   PV Size 44.90 GB / not usable 22.89 MB
   Allocatable yes
   PE Size (KByte) 32768
   Total PE 1436
   Free PE 640
   ...

9. Resize the LVM Logical Volume
   % lvresize /dev/VolGroup00/LogVol00 -l +100%FREE
Extending logical volume LogVol00 to 43.88 GB
Logical volume LogVol00 successfully resized
10. Grow the File system
    % resize2fs /dev/VolGroup00/LogVol00
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/VolGroup00/LogVol00 is mounted on /; on-line resizing required
Performing an on-line resize of /dev/VolGroup00/LogVol00 to 11501568 (4k) blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 11501568 blocks long.