INSTALL/CreatePersistentImg.sh

   1 #!/bin/sh
   2
   3 size=1024
   4 fstype=ext4
   5 label=casper-rw
   6
   7 print_usage() {
   8     echo 'Usage:  CreatePersistentImg.sh [ -s size ] [ -t fstype ] [ -l LABEL ]'
   9     echo '  OPTION: (optional)'
  10     echo '   -s size in MB, default is 1024'
  11     echo '   -t filesystem type, default is ext4  ext2/ext3/ext4/xfs are supported now'
  12     echo '   -l label, default is casper-rw'
  13     echo ''
  14 }
  15
  16 while [ -n "$1" ]; do
  17     if [ "$1" = "-s" ]; then
  18         shift
  19         size=$1
  20     elif [ "$1" = "-t" ]; then
  21         shift
  22         fstype=$1
  23     elif [ "$1" = "-l" ]; then
  24         shift
  25         label=$1
  26     elif [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
  27         print_usage
  28         exit 0
  29     else
  30         print_usage
  31         exit 1
  32     fi
  33     shift
  34 done
  35
  36
  37 # check label
  38 if [ -z "$label" ]; then
  39     echo "The label can NOT be empty."
  40     exit 1
  41 fi
  42
  43 # check size
  44 if echo $size | grep -q "^[0-9][0-9]*$"; then
  45     if [ $size -le 1 ]; then
  46         echo "Invalid size $size"
  47         exit 1
  48     fi
  49 else
  50     echo "Invalid size $size"
  51     exit 1
  52 fi
  53
  54
  55 # check file system type
  56 # nodiscard must be set for ext2/3/4
  57 # -K must be set for xfs
  58 if echo $fstype | grep -q '^ext[234]$'; then
  59     fsopt='-E nodiscard'
  60 elif [ "$fstype" = "xfs" ]; then
  61     fsopt='-K'
  62 else
  63     echo "unsupported file system $fstype"
  64     exit 1
  65 fi
  66
  67 # 00->ff avoid sparse file
  68 dd if=/dev/zero  bs=1M count=$size | tr '\000' '\377' > persistence.dat
  69 sync
  70
  71 freeloop=$(losetup -f)
  72
  73 losetup $freeloop persistence.dat
  74
  75 mkfs -t $fstype $fsopt -L $label $freeloop
  76
  77 sync
  78
  79 losetup -d $freeloop
  80