[OE-core] [PATCH 3/3] Empty image: filesystem allocation

[Alex Franco]

Increase sparse image block size when ROOTFS_SIZE is smaller than
the minimum needed for ext4 to fit into it.

[YOCTO #7664]

Signed-off-by: Alex Franco <alejandro.franco at linux.intel.com>
---
 meta/classes/image_types.bbclass | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/meta/classes/image_types.bbclass b/meta/classes/image_types.bbclass
index 35ceb7b..61ce222 100644
--- a/meta/classes/image_types.bbclass
+++ b/meta/classes/image_types.bbclass
@@ -49,8 +49,16 @@ oe_mkext234fs () {
 		extra_imagecmd=$@
 	fi
 
+	# If generating an empty image the size of the sparse block should be large
+	# enough to allocate an ext4 filesystem using 4096 bytes per inode, this is
+	# about 60K, so dd needs a minimum count of 60, with bs=1024 (bytes per IO)
+	eval local COUNT=\"0\"
+	eval local MIN_COUNT=\"60\"
+	if [ $ROOTFS_SIZE -lt $MIN_COUNT ]; then
+		eval COUNT=\"$MIN_COUNT\"
+	fi
 	# Create a sparse image block
-	dd if=/dev/zero of=${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.$fstype seek=$ROOTFS_SIZE count=0 bs=1k
+	dd if=/dev/zero of=${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.$fstype seek=$ROOTFS_SIZE count=$COUNT bs=1024
 	mkfs.$fstype -F $extra_imagecmd ${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.$fstype -d ${IMAGE_ROOTFS}
 }
 
-- 
2.5.0