image_types: add IMAGE_ROOTFS_EXTRA_SPACE

[YOCTO #886]

This address 2 needs after the IMAGE_ROOTFS_SIZE is cleaned up, by
removing the _ext2/3 overrides it allows for a cleaner override
using IMAGE_ROOTFS_SIZE to create a large rootfs, or by setting the
IMAGE_ROOTFS_EXTRA_SPACE, will allow for extra space allocated in Kilobytes
above the base size (determined by du of the rootfs * IMAGE_OVERHEAD_FACTOR,
default of 1.3).

(From OE-Core rev: 367934ada7c081ba3fc95f02dc14c7d6f97bfccb)

Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 5 insertions, 1 deletions

diff --git a/meta/classes/image_types.bbclass b/meta/classes/image_types.bbclass
index 69f859e39b..601a5fbb4d 100644
--- a/meta/classes/image_types.bbclass
+++ b/meta/classes/image_types.bbclass
@@ -13,7 +13,7 @@ def get_imagecmds(d):
 
 runimagecmd () {
         # Image generation code for image type ${type}
-        ROOTFS_SIZE=`du -ks ${IMAGE_ROOTFS}|awk '{size = $1 * ${IMAGE_OVERHEAD_FACTOR}; print (size > ${IMAGE_ROOTFS_SIZE} ? size : ${IMAGE_ROOTFS_SIZE}) }'`
+        ROOTFS_SIZE=`du -ks ${IMAGE_ROOTFS}|awk '{size = $1 * ${IMAGE_OVERHEAD_FACTOR} + ${IMAGE_ROOTFS_EXTRA_SPACE}; print (size > ${IMAGE_ROOTFS_SIZE} ? size : ${IMAGE_ROOTFS_SIZE}) }'`
         ${cmd}
         cd ${DEPLOY_DIR_IMAGE}/
         rm -f ${DEPLOY_DIR_IMAGE}/${IMAGE_LINK_NAME}.${type}
diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index 18028f3001..35fd6f864f 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -350,6 +350,10 @@ IMAGE_LINK_NAME = "${IMAGE_BASENAME}-${MACHINE}"
 # This option allows for a precentage overage of the actaul image size rather than a
 # fixed extra space
 IMAGE_OVERHEAD_FACTOR ?= 1.3
+# This option allow for adding addition space in K above and beyond what the 
+# IMAGE_OVERHEAD_FACTOR might add. To set a fixed size then overrideing IMAGE_ROOTFS_SIZE
+# with the max size one wants should do the trick
+IMAGE_ROOTFS_EXTRA_SPACE = "0"
 
 EXTRA_IMAGEDEPENDS = ""