[PATCH] Fix size calculation for EFI image
CD creation fails with "disk full", because of rounding errors.
The minimum size of data-allocation is a 'cluster', which is a
power-of-two multiple of sectors.
mkfs.msdos chooses minimum FAT and cluster size for image: FAT12<16G
mkfs.msdos uses block-count where a block is 1024 B, but must be rounded
up to track_size with 32 sectors.
Round up each file to clusters before summing.
A sub-directory entry needs 1 cluster minimum.
---
tools/boot/wheezy/boot-x86 | 37 +++++++++++++++++++++++++++++--------
1 file changed, 29 insertions(+), 8 deletions(-)
diff --git a/tools/boot/wheezy/boot-x86 b/tools/boot/wheezy/boot-x86
index bf79d6d..d1d3d16 100644
--- a/tools/boot/wheezy/boot-x86
+++ b/tools/boot/wheezy/boot-x86
@@ -420,17 +420,38 @@ if [ -d boot$N/isolinux/grub ] ; then
>> $CDDIR/boot/grub/grub.cfg
# Stuff the EFI boot files into a FAT filesystem, making it as
- # small as possible. 24KiB headroom seems to be enough;
- # (x+31)/32*32 rounds up to multiple of 32.
- # This is the same as in efi-image, but we need to redo it here in
- # the case of a multi-arch amd64/i386 image
+ # small as possible.
- size=0
+ sector_bytes=512 # -S
+ cluster_sectors=4 # -s
+ cluster_bytes=$((sector_bytes * cluster_sectors))
+
+ clusters=2 # 1 cluster for each sub-directory
for file in $CDDIR/efi/boot/boot*.efi; do
- size=$(($size + $(stat -c %s "$file")))
+ [ -f "$file" ] || continue
+ clusters=$(($clusters + (($(stat -c %s "$file") + $cluster_bytes - 1) / $cluster_bytes)))
done
-
- blocks=$((($size / 1024 + 55) / 32 * 32 ))
+ reserved_sectors=1 # boot-sector -R
+ reserved_bytes=$(($reserved_sectors * $sector_bytes))
+ fat_copies=2 # -f
+ if [ "$clusters" -le $(((1 << 12) - 2)) ]; then
+ fat_entry_bytes=3/2 # -F
+ elif [ "$clusters" -le $(((1 << 16) - 2)) ]; then
+ fat_entry_bytes=2 # -F
+ else
+ fat_entry_bytes=4 # -F
+ fi
+ fat_bytes=$((($clusters * $fat_entry_bytes + $sector_bytes - 1) / $sector_bytes * $sector_bytes))
+ root_entries=512 # -r
+ root_entry_bytes=32
+ root_bytes=$(($root_entries * root_entry_bytes))
+ size=$(($reserved_bytes + $fat_copies * $fat_bytes + $root_bytes + $clusters * $cluster_bytes))
+
+ track_sectors=32
+ track_bytes=$((sector_bytes * $track_sectors))
+ tracks=$((($size + $track_bytes - 1) / $track_bytes))
+ block_bytes=1024
+ blocks=$(($tracks * $track_bytes / $block_bytes))
rm -f $CDDIR/boot/grub/efi.img
mkfs.msdos -C "$CDDIR/boot/grub/efi.img" $blocks >/dev/null
--
2.1.4
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