The current implementation in how partition is created for ext2 img
it looks a bit bad.
This patch makes the partition in more standarized way, respecting
cylinder alignement:
* The size of resulting image will be in cylinder multiple ~8MB.
* Use fdisk instead of sfdisk (sfdisk write some bad information)
* Make the result image in one pass, instead of concatenating.
Also the advantage is that with this can add another partitions
without any issues in the usb-flash-drive with this .img.
For example of current situation:
qemu-system-x86_64 -hda archlinux-avr.toolchain.img -serial stdio
---------------------------------------------------------------------
[root@avr ~]# fdisk /dev/sda
Command (m for help): p
Disk /dev/sda: 223 MB, 223974400 bytes
59 heads, 41 sectors/track, 180 cylinders
Units = cylinders of 2419 * 512 = 1238528 bytes
Disk identifier: 0x00000000
Device Boot Start End Blocks Id System
/dev/sda1 * 1 181 218693+ 83 Linux
Partition 1 has different physical/logical beginnings (non-Linux?):
phys=(0, 1, 1) logical=(0, 1, 23)
Partition 1 has different physical/logical endings:
phys=(27, 58, 41) logical=(180, 49, 21)
Command (m for help): v
Partition 1 has different physical/logical beginnings (non-Linux?):
phys=(0, 1, 1) logical=(0, 1, 23)
Partition 1 has different physical/logical endings:
phys=(27, 58, 41) logical=(180, 49, 21)
Partition 1: previous sectors 437449 disagrees with total 67731
62 unallocated 512-byte sectors
Command (m for help):
---------------------------------------------------------------------
qemu-system-x86_64 -hda archlinux-avr.toolchain-fix.img -serial stdio
---------------------------------------------------------------------
[root@avr ~]# fdisk /dev/sda
Command (m for help): p
Disk /dev/sda: 230 MB, 230307840 bytes
255 heads, 63 sectors/track, 28 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x5c94ca4f
Device Boot Start End Blocks Id System
/dev/sda1 * 1 28 224878+ 83 Linux
Command (m for help): v
62 unallocated 512-byte sectors
---------------------------------------------------------------------
Signed-off-by: Gerardo Exequiel Pozzi <vmlinuz386(a)yahoo.com.ar>
---
archiso/mkarchiso | 48 +++++++++++++++++++++++++++++-------------------
1 files changed, 29 insertions(+), 19 deletions(-)
diff --git a/archiso/mkarchiso b/archiso/mkarchiso
index 7b706ca..b6d0f54 100755
--- a/archiso/mkarchiso
+++ b/archiso/mkarchiso
@@ -261,39 +261,49 @@ command_iso () {
command_usb () {
_imgcommon
-
- fsimg="${imgname}.part1"
+
+ modprobe -q loop
+
+ # Calculate cylinder size in bytes
+ CYL_SIZE=$((255*63*512))
+
+ # First partition offset
+ PART_OFFSET=$((63*512))
# ext2 overhead's upper bound is 6%, empirically tested up to 1GB
rootsize=$(du -bs "${work_dir}/iso" | cut -f1)
- imgsz=$(( (${rootsize}*106)/100/512 + 1)) # image size in sectors
+ imgsz=$(( (${rootsize}*106)/100/${CYL_SIZE} + 1 )) # image size in cylinders
+
+ # Get next free loop device
+ devloop=$(losetup -f)
# create the filesystem image file
- dd if=/dev/zero of="$fsimg" bs=512 count="$imgsz"
+ dd if=/dev/zero of="$imgname" bs="$CYL_SIZE" count="$imgsz"
+
+ # Setup a loop device, and skip the first 63 sectors
+ losetup "$devloop" -o "$PART_OFFSET" "$imgname"
# create a filesystem on the image
- mke2fs -m 0 -F -L "${LABEL}" "$fsimg"
+ mke2fs -m 0 -F -L "${LABEL}" "$devloop"
# mount the filesystem and copy data
- modprobe loop
TMPDIR=$(mktemp -d archiso-usbXXXXXX)
- mount -o loop "$fsimg" "$TMPDIR"
+ mount "$devloop" "$TMPDIR"
cp -a "${work_dir}"/iso/* "$TMPDIR"
- umount "$TMPDIR"
+ umount -d "$TMPDIR"
rm -rf "$TMPDIR"
- # add sectors 0-62, then glue together
- dd if=/dev/zero of="${imgname}" bs=512 count=63
- cat "$fsimg" >> "${imgname}"
- rm "$fsimg"
-
# create a partition table
- # if this looks like voodoo, it's because it is
- sfdisk -uS -f "${imgname}" << EOF
-63,$imgsz,83,*
-0,0,00
-0,0,00
-0,0,00
+ fdisk -C "$imgsz" -H 255 -S 63 "$imgname" << EOF
+n
+p
+1
+
+
+a
+1
+p
+w
EOF
# install grub on the image
--
1.6.5.1