#!/bin/bash

PATH=/usr/bin:/sbin:/opt/VRTS/bin; export PATH

# Dusan U. Baljevic dusan.baljevic@ieee.org
#
# The original script was published in
# "XP StorageWorks Summary Guide for Thin Provisioning"
# 
# 18 Apr 2012
#
# The script could be improved much more,
# but that is left for the next exercise.

umask 022

ARGCNT="$#"

SCRIPT="`basename $0`"

USAGE="USAGE: $SCRIPT -f filesystem [ -p percent-fill] [-h] 
       -h               Print help file
       -f filesystem    Filesystem in which to reclaim thin-provisioned space 
       -p percent-fill  Threshold to fill filesystem 
"

# Process command line arguments.
#
while getopts hf:p: c
do
        case $c in
                f) FS="$OPTARG" ;;
                h) echo "$USAGE"; exit 0 ;;
                p) PCTFILL="$OPTARG" ;;
                \?) echo "$USAGE"; exit 1 ;;
        esac
done
shift `expr $OPTIND - 1`

if [ ! "$PCTFILL" ]; then
   PCTFILL=90
fi

# Tunables
#
zfile="zeroreclaimfile.raw"
SLEEPTIME=5

if [ ! "$FS" ]; then
   printf "ERROR: Filesystem argument not supplied\n"
   echo "$USAGE"
   exit 1
fi

if [ "$ARGCNT" -lt 2 ]; then
   printf "ERROR: Must supply one filesystem mount point\n";
   exit 1
fi

FSTYP=$(df -n $FS | nawk '{print $3}')
 
MOUNT=$(df -k $FS | nawk '!/Filesystem/ {print $6}')
if [ "$MOUNT" != "$FS" ]; then
   printf "INFO: Filesystem argument supplied \"$FS\" is not a mount point\n"
   printf "INFO: It is contained within \"$MOUNT\"\n"
   exit 1
fi

####### SETUP SIGNAL HANDLING ##############
#
trap "INTERRUPT_HANDLER" 1 2 3 9 15

# Catch interrupts and handle them
#
INTERRUPT_HANDLER() {
   trap "" 1 2 3 9 15
   printf "\n\nWARN: Interrupt received... Terminating program and cleaning up\n"
   # killing child processes
   #
   for PID in `ps -f | nawk -v PPID=$$ '{if ( $3 == PPID ) print $2}'` ; do
      if [ "$PID" != "PID" -a $PID -ne $$ ] ; then
         echo "INFO: Executing termination of process ID $PID 2>/dev/null"
         kill $PID 2>/dev/null
      fi
   done
   cleanup $FS
   exit 0
}

status() {
   PCT=$(df -k $1 | nawk '!/Filesystem/ {print $5}' | sed 's/%//g')
   printf "INFO: Initial filesystem \"$1\" utilization: $PCT percent\n\n"
   
   while true
   do
      PCT=$(df -k $1 | nawk '!/Filesystem/ {print $5}' | sed 's/%//g')
      printf "INFO: Current filesystem \"$1\" utilization: $PCT percent...\n"
      if [ $PCT -gt $(expr $PCTFILL + 1 )  ]; then
         printf "\nINFO: Filesystem \"$1\" exceeded the threshold of $PCTFILL percent\n"
         printf "INFO: Stopping space reclamation process and continuing with cleanup\n"
         #Send term signal to myself
         kill -1 $$
      fi

      printf "INFO: Running filesystem space reclamation process...\n"
      ps -ef | egrep -v grep | grep $(cat $1/$zfile.pid)
      if [ $? -eq 0 ]; then
         sleep $SLEEPTIME
      else
         return
      fi
   done
}

cleanup() {
   printf "\nINFO: Calling sync...\n"
   sync
   sync
   sleep $SLEEPTIME
   printf "INFO: Completed Successfully... removing temporary files...\n"
   rm $1/${zfile} $1/${zfile}.pid 2>/dev/null 2>&1
   sleep $SLEEPTIME 
   df -k $1
}

case $FSTYP in
   vxfs|VXFS) fsadm -R $FS >/dev/null 2>&1 
              if [ $? -eq 0 ]; then
                 exit 0
              else
                 continue
              fi ;;
esac

if [ -f $FS/$zfile ]; then
   printf "ERROR: \"$FS/$zfile\" exists (previous run did not complete?)... exiting\n"
   exit 1
fi

line=$(df -k $FS | nawk '!/Filesystem/ {print}')
CURCAP=$(echo $line | nawk '{print $5}' | sed 's/%//g')
CAPKB=$(echo $line | nawk '{print $2}')
CAPUSEDKB=$(echo $line | nawk '{print $3}')

if [ $CURCAP -gt $(expr $PCTFILL + 1 ) ]; then
   printf "INFO: Current capacity of \"$FS\" exceeds threshold of fill capacity currently set at $PCTFILL\n"
   printf "INFO: No operation will be performend on \"$FS\"\n"
else
   printf "INFO: Filesystem \"$FS\" has capacity $(expr $CAPKB / 1024) MB\n"
   printf "INFO: Filling filesystem \"$FS\" utilization to $PCTFILL percent\n\n"

   FSEND=$(expr $CAPKB \* $PCTFILL / 100)
   KB=$(expr $FSEND - $CAPUSEDKB)
   COUNT=$(echo "$KB / 1024" | bc)

   echo "INFO: Running dd if=/dev/zero of=$FS/$zfile bs=1024k count=$COUNT > /dev/null 2>&1 &"
   dd if=/dev/zero of=$FS/$zfile bs=1024k count=$COUNT > /dev/null 2>&1 &

   echo $! > $FS/$zfile.pid

   status $FS
   cleanup $FS
fi

exit 0