rootfs-resize

#!/usr/bin/bash
#
# rootfs-resize :: Fedora ARM root partition resize service script
#
# Version 0.7 - 2012-07-30
#
# CTyler <ctyler@fedoraproject.org> 2012-01-30 - 2012-07-30
# Brendan Conoboy <blc@redhat.com> 2012-05-06
# birger <birger@birger.sh> 2012-05-06
#
#

#
#    rootfs-reszie - SD card resize service
#
#    Copyright (C)2012 Chris Tyler and others (see above)
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
#    MA  02110-1301  USA
#

#
# If /.nofsresize exists, or 'nofsresize' was passed
# as a kernel command line argument, disable this
# service and exit.
#
# If /.rootfs-repartition exists, repartition /
#
# If /.rootfs-resize exists, resize /
#

set -e
PATH=/usr/bin:/usr/sbin
export PATH

# If the kernel commandline contains "nofsresize" or
# the file /.nofsresize exist, then disable this service
# and exit

if grep --silent -i "nofsresize" /proc/cmdline || [[ -f /.nofsresize ]] ; then
  systemctl disable rootfs-resize.service
  exit 0
fi

# If the resize flag files do not exist, then exit

if [[ ! -f /.rootfs-repartition && ! -f /.rootfs-resize ]] ; then
  exit 0
fi

PDEV=`cat /proc/self/mountinfo | grep '/ / ' | sed -n 's@.* \(/dev/.*\) .*@\1@p'`

if [ "$PDEV" = "/dev/root" ]; then
  for i in $(cat /proc/cmdline); do
    case "$i" in
      root=*)
        PDEV=${i:5}
        ;;
    esac
  done
fi

case $PDEV in
  /dev/sd*)
    DEV="${PDEV%%[0-9]*}"
    PNUM="${PDEV#${DEV}}"
  ;;
  /dev/mmcblk*)
    DEV="${PDEV%%p[0-9]*}"
    PNUM="${PDEV#${DEV}p}"
  ;;
  *)
    echo "$0: Unknown root device type $PDEV. Exiting"
    exit 1
  ;;
esac

if [[ X$DEV = X ]] || [[ X$PDEV = X ]] || [[ X$PNUM = X ]]; then
  echo "$0: Was unable to determine device, partition, or number. Exiting."
  exit 1
fi

if [[ -f /.rootfs-repartition ]]; then

  if [[ $PNUM -ne $(fdisk -l "$DEV"|grep -c "^/dev/") ]] ; then 
    echo "$0: $DEV is not the last partition, exiting."
    exit 0
  fi

  echo "$0: Phase 1 - Changing the parition size." 
  echo "$0: Using $PDEV on $DEV for resize"

  # HDG: hardcode partition start for now otherwise alignment messes things up
  # See: https://bugzilla.redhat.com/show_bug.cgi?id=974631
  echo -e "d\n$PNUM\nn\np\n$PNUM\n1251954\n\np\nw\n"|fdisk $DEV >/dev/null 2>&1 || true
  echo "$0: Repartition done, rebooting for next phase of resize."
  touch /.rootfs-resize
  rm -f /.rootfs-repartition
  reboot

elif [[ -f /.rootfs-resize ]]; then

  echo "$0: Phase 2 - Resizing the root partition."
  ionice -n 7 resize2fs -p $PDEV

  if [[ -f /.swapsize ]]
  then
    SWAPSIZE="0$(head -1 </.swapsize|tr -cd "0-9")"
    FREESPACE="$(df  /|sed -n "s|^/[^ ]* \+[0-9]\+ \+[0-9]\+ \+\([0-9]\+\) .*$|\1|p")"

    # Ensure that the swap size is non-negative
    if [[ "$SWAPSIZE" -lt 0 ]]
    then
      SWAPSIZE=0
    fi

    # Use half of the available root filesystem space, in MB, as the max swap size
    if [[ "$SWAPSIZE" -gt "$((FREESPACE / 2048))" ]]
    then
      SWAPSIZE="$FREESIZE"
    fi

    # If the swap file is not already present, create it
    # Create file as /swap0.part in case we're interrupted
    if [[ ! -f /swap0 && "$SWAPSIZE" -gt 0 ]]
    then
      echo "$0: Phase 3 - Creating $SWAPSIZE MB swap file /swap0"
      ionice -n 7 dd if=/dev/zero of=/swap0.part bs=1M count="$SWAPSIZE"
      mkswap /swap0.part
      mv /swap0.part /swap0

    else

      echo "$0: Swap file already exists - not creating."

    fi

    if grep -q "^/swap0" /etc/fstab >/dev/null
    then
      :
    else
      echo -e "/swap0\tswap\tswap" >>/etc/fstab
    fi
    swapon -a
    rm -f /.swapsize

  fi
  rm -f /.rootfs-resize
  echo "$0: Partition resizing completed."
fi