Increase Filesystem size in .sdcard image of Yocto Build

Have you ever came across the situation in which after flashing the .sdcard image out of your Yocto build and you need to increase the root filesystem size? well i came across it many times. My default goto option was using gparted to increase the size by the required size. Also I used to wonder always why the free space is around 30% of the Filesystem size. Well, here is my finding

Normally in Yocto following 3 keywords define the space/free space in .sdcard image

IMAGE_ROOTFS_SIZE        : Defines the size in Kbytes for the generated image.
IMAGE_ROOTFS_EXTRA_SPACE : Defines additional free disk space default to "0"
IMAGE_OVERHEAD_FACTOR     : Defines a multiplier to the initial image & default is 1.3 (30% free space) for this variable.

user can set these values in local.conf according to the need while the following logic is applied by the Yocto

image-du = Returned value of the du command on the image.
overhead = IMAGE_OVERHEAD_FACTOR
rootfs-size = IMAGE_ROOTFS_SIZE
internal-rootfs-size = Initial root filesystem size before any modifications.
xspace = IMAGE_ROOTFS_EXTRA_SPACE

if (image-du * overhead) < rootfs-size:
	internal-rootfs-size = rootfs-size + xspace
else:
	internal-rootfs-size = (image-du * overhead) + xspace

So Simple way to define an extra space would be like

IMAGE_OVERHEAD_FACTOR = “1.0” # no overhead
IMAGE_ROOTFS_EXTRA_SPACE = "20971520" #20GB extra space