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=$1
  26     else
  27         print_usage
  28         exit 1
  29     fi
  30     shift
  31 done
  32
  33
  34 # check label
  35 if [ -z "$label" ]; then
  36     echo "The label can NOT be empty."
  37     exit 1
  38 fi
  39
  40 # check size
  41 if echo $size | grep -q "^[0-9][0-9]*$"; then
  42     if [ $size -le 1 ]; then
  43         echo "Invalid size $size"
  44         exit 1
  45     fi
  46 else
  47     echo "Invalid size $size"
  48     exit 1
  49 fi
  50
  51
  52 # check file system type
  53 # nodiscard must be set for ext2/3/4
  54 # -K must be set for xfs
  55 if echo $fstype | grep -q '^ext[234]$'; then
  56     fsopt='-E nodiscard'
  57 elif [ "$fstype" = "xfs" ]; then
  58     fsopt='-K'
  59 else
  60     echo "unsupported file system $fstype"
  61     exit 1
  62 fi
  63
  64 # 00->ff avoid sparse file
  65 dd if=/dev/zero  bs=1M count=$size | tr '\000' '\377' > persistence.img
  66 sync
  67
  68 freeloop=$(losetup -f)
  69
  70 losetup $freeloop persistence.img
  71
  72 mkfs -t $fstype $fsopt -L $label $freeloop
  73
  74 sync
  75
  76 losetup -d $freeloop
  77