#!/bin/bash

# Author: Alan J. Pippin
# Description: This script will attempt to scrub a given pool.
#              This script ensures that only 1 scrub operation is 
#              running at any given time. This serializes the zfs 
#              scrub process for any pool.

# source our configuration
config="${0%/*}/zfs-scripts.conf"
[ -e "${config}.dist" ] && . ${config}.dist
[ -e "${config}" ] && . ${config}

exec >> $logdir/zfs-scrub.log 2>&1

pools="$*"
maxsleeptime=360

if [ -z "$pools" ]; then
   echo "-E- Usage: $0 <pools>"
   exit 1
fi

fatal_and_exit() {
  # echo message to terminal
  echo -e 2>&1 "$1"
  # send email notification
  echo -e "$1" | $mailx -s "zfs scrub on $hostname failed" "$mailto"
  exit 1
}

for i in $pools
do
  # Import the local pool if needed and option was given to do so, else error out
  zpool list -H "$i" >/dev/null 2>&1
  if [ $? != 0 ]; then
    if [[ $import_export_backup_pool == 1 ]] && [[ "$i" =~ "$backup_pool" ]]; then
      zpool import $i
      if [ $? != 0 ]; then
        fatal_and_exit "-E- unable to import the pool $i"
      fi
    else
      fatal_and_exit "-E- The local pool, '$i' doesn't seem to exist."
    fi
  fi

  # Check to see if any zfs filesystem has a scrub being performed on it now.
  # If it does, we cannot perform more than one scrub operation at a time.
  while true; do
    zpool status | grep scan: | grep "in progress" > /dev/null 2>&1
    if [ $? == 0 ]; then
        # Another zpool scrub operation is already running
        # Wait until it is done before continuing
        ransleep=$(($RANDOM % $maxsleeptime))
        sleep $ransleep
    else
        # Another zpool scrub operation is not running
        break
    fi
  done

  date=`date`
  echo "$date: Scrub started for zfs pool $i"
  zpool scrub $i

  # Wait until the scrub completes, and check for any errors
  while true; do
    zpool status $i 2>/dev/null | grep scan: | grep "in progress" > /dev/null 2>&1
    if [ $? == 0 ]; then
        # Our zpool scrub operation is still running
        # Wait until it is done before continuing
        ransleep=$(($RANDOM % $maxsleeptime))
        sleep $ransleep
    else
        # Our scrub operation has completed
        break
    fi
  done

  date=`date`
  echo "$date: Scrub completed for zfs pool $i"

  # Import the local pool if needed and option was given to do so, else error out
  # do this so we can check its status to see if it repaired any errors or not
  zpool list -H "$i" >/dev/null 2>&1
  if [ $? != 0 ]; then
    if [[ $import_export_backup_pool == 1 ]] && [[ "$i" =~ "$backup_pool" ]]; then
      zpool import $i
      if [ $? != 0 ]; then
        fatal_and_exit "-E- unable to import the pool $i"
      fi
    else
      fatal_and_exit "-E- The local pool, '$i' doesn't seem to exist."
    fi
  fi

  # Check for any scrub errors
  zpool status $i | grep scan: 
  zpool status $i | grep scan: | grep "with 0 errors" > /dev/null 2>&1
  if [ $? != 0 ]; then
    # The scrub found errors
    zpool status $i | $mailx -s "zpool scrub on $hostname $i found errors" "$mailto" 
  fi 

  # Export the local pool if told to do so
  if [[ $import_export_backup_pool == 1 ]] && [[ "$i" =~ "$backup_pool" ]]; then
    # Don't export the pool if there is a currently running zfs-replicate operation
    ps -ef | grep -q "zfs-replicate" | grep -v grep
    if [ $? != 0 ]; then
      # Only export the pool if it is still imported
      zpool list -H "$i" >/dev/null 2>&1
      if [ $? == 0 ]; then
        zpool export $i
        if [ $? != 0 ]; then
          echo "-E- unable to export the local pool $i"
          zpool status $i | $mailx -s "zpool scrub on $hostname unable to export the local pool $i" "$mailto"
        fi
      fi
    fi
  fi

done