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-rw-r--r--meta/classes/bootimg.bbclass45
1 files changed, 36 insertions, 9 deletions
diff --git a/meta/classes/bootimg.bbclass b/meta/classes/bootimg.bbclass
index b50202f68..df3ee7315 100644
--- a/meta/classes/bootimg.bbclass
+++ b/meta/classes/bootimg.bbclass
@@ -103,19 +103,46 @@ build_hddimg() {
grubefi_hddimg_populate
fi
- # Determine the 1024 byte block count for the final image.
- BLOCKS=`du --apparent-size -ks ${HDDDIR} | cut -f 1`
- SIZE=`expr $BLOCKS + ${BOOTIMG_EXTRA_SPACE}`
+ # Calculate the size required for the final image including the
+ # data and filesystem overhead.
+ # Sectors: 512 bytes
+ # Blocks: 1024 bytes
+
+ # Determine the sector count just for the data
+ SECTORS=$(expr $(du --apparent-size -ks ${HDDDIR} | cut -f 1) \* 2)
+
+ # Account for the filesystem overhead. This includes directory
+ # entries in the clusters as well as the FAT itself.
+ # Assumptions:
+ # < 16 entries per directory
+ # 8.3 filenames only
+
+ # 32 bytes per dir entry
+ DIR_BYTES=$(expr $(find ${HDDDIR} | tail -n +2 | wc -l) \* 32)
+ # 32 bytes for every end-of-directory dir entry
+ DIR_BYTES=$(expr $DIR_BYTES + $(expr $(find ${HDDDIR} -type d | tail -n +2 | wc -l) \* 32))
+ # 4 bytes per FAT entry per sector of data
+ FAT_BYTES=$(expr $SECTORS \* 4)
+ # 4 bytes per FAT entry per end-of-cluster list
+ FAT_BYTES=$(expr $FAT_BYTES + $(expr $(find ${HDDDIR} -type d | tail -n +2 | wc -l) \* 4))
+
+ # Use a ceiling function to determine FS overhead in sectors
+ DIR_SECTORS=$(expr $(expr $DIR_BYTES + 511) / 512)
+ # There are two FATs on the image
+ FAT_SECTORS=$(expr $(expr $(expr $FAT_BYTES + 511) / 512) \* 2)
+ SECTORS=$(expr $SECTORS + $(expr $DIR_SECTORS + $FAT_SECTORS))
+
+ # Determine the final size in blocks accounting for some padding
+ BLOCKS=$(expr $(expr $SECTORS \* 2) + ${BOOTIMG_EXTRA_SPACE})
# Ensure total sectors is an integral number of sectors per
- # track or mcopy will complain. Sectors are 512 bytes, and and
- # we generate images with 32 sectors per track. This calculation
- # is done in blocks, which are twice the size of sectors, thus
- # the 16 instead of 32.
- SIZE=$(expr $SIZE + $(expr 16 - $(expr $SIZE % 16)))
+ # track or mcopy will complain. Sectors are 512 bytes, and we
+ # generate images with 32 sectors per track. This calculation is
+ # done in blocks, thus the mod by 16 instead of 32.
+ BLOCKS=$(expr $BLOCKS + $(expr 16 - $(expr $BLOCKS % 16)))
IMG=${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.hddimg
- mkdosfs -n ${BOOTIMG_VOLUME_ID} -S 512 -C ${IMG} ${SIZE}
+ mkdosfs -F 32 -n ${BOOTIMG_VOLUME_ID} -S 512 -C ${IMG} ${BLOCKS}
# Copy HDDDIR recursively into the image file directly
mcopy -i ${IMG} -s ${HDDDIR}/* ::/