file_changed.sh

#!/bin/bash 
# Original script here: https://gist.github.com/Harshavardhana/6502979r
#TARPATH="/root/bin/tar-1.23/usr/local/bin/"
TARPATH="/root/bin/tar-1.26/usr/local/bin/"
_init()
{
    DIRZ=$( seq 1 100 )
}

cleanup()
{
    echo "Cleaning the test"
    if [ -f /tmp/tar_read_errors.txt ]; then
        rm -f /tmp/tar_read_errors.txt;
    fi

    for dir in $DIRZ
    do 
        rm -fr $dir
        rm -fr ${dir}.tar
    done
}
    
samples()
{
    echo "Creating samples"
    # create dirs 
    for dir in $DIRZ 
    do 
        [ -f $dir/afile ] && continue
        mkdir $dir
        if [ "$1" == "sync" ]; then
            dd if=/dev/urandom of=$dir/afile bs=4096 count=10 oflag=sync >/dev/null 2>&1
        else
            dd if=/dev/urandom of=$dir/afile bs=4096 count=10 >/dev/null 2>&1
        fi
    done 
}

readtest(){
    echo "Performing read test"
    # do the tars 
    for dir in $DIRZ
    do
        $TARPATH/tar cf ${dir}.tar $dir 2>>/tmp/tar_read_errors.txt
    done
}

main()
{
    cleanup;

    if [ "$1" == "sync" ]; then
        echo "O_SYNC is turned on"
        samples $1;
        readtest;
        count=`wc -l /tmp/tar_read_errors.txt`
    elif [ "$1" == "flush" ]; then
        echo "Flushing filesystem buffers";
        samples;
        sync;
        readtest;
        count=`wc -l /tmp/tar_read_errors.txt`
    else
        samples;
        readtest;
        count=`wc -l /tmp/tar_read_errors.txt`
    fi
    echo "Total read failures ${count}"
}

_init "$@" && main "$@"