Empty image: filesystem allocation

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

[YOCTO #7664]

(From OE-Core rev: 6938791ff97a23430afb4aa16d71aa8729a12ead)

Signed-off-by: Alex Franco <alejandro.franco@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/meta/classes/image_types.bbclass b/meta/classes/image_types.bbclass
index 8547574a1d..2fd4c3794a 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}
 }