#!/bin/bash

# collect_updatelogs: collect MDT updatelog files on live server node.
#
# This tool retrieves updatelogs from live server for further analysis
#
# Tool does the following:
# - get update_log catlist using debugfs to find per-MDT update catalog FIDs
# - get llog catalogs according with that list
# - optionally get everything else from update_log_dir
#
# Script requires parameter is physical device of MDT server
#
# Script saves updatelog with prefixes 'catlog<mdtidx>' to identify them
# easily
#

PROG=$(basename $0)
LLOG_READER=${LLOG_READER:-llog_reader}
DEBUGFS=${DEBUGFS:-debugfs}

usage() {
    cat -- <<USAGE 1>&2
usage: collect_updatelog [--help|-h] [--mdt|-m indices] [--path|-p <path>]\n
			 <mdt_device>
	--help|-h	     show this usage message
	--mdt|-m <index,...> get llogs of selected MDTs only
	--path|-p <path>     save all llogs into directory by given path

The 'mdt_device' argument should be physical MDT device being mounted.

Examples:
      collect_updatelog /dev/sda1
      collect_updatelog -p /tmp/llogs_mdt0 /dev/sda1
      collect_updatelog -m 0,1 /dev/sda1
USAGE
    exit 1
}

OPT_PATH="./"
OPT_DEV=""
OPT_MDTS=()
OPT_MDTIDX=()

# Examine any long options and arguments
while [ -n "$*" ]; do
	arg="$1"
	case "$arg" in
	-h|--help) usage;;
	-m|--mdt) OPT_MDTIDX=($(echo $2 | tr "," " "));;
	-p|--path) OPT_PATH="$2"; shift;;
	*)
	   [ -e "$arg" ] && OPT_DEV="$arg" && break
	esac
	shift
done

collect_updatelog() {
	local mdt_dev=$OPT_DEV
	local dest=$OPT_PATH
	local catlist=${dest}/update_log
	local llogdir=${dest}/update_log_dir
	local length=0

	if [[ ! $(which $DEBUGFS 2>/dev/null) ]] ; then
		echo "$PROG: $DEBUGFS is missing."
		exit 1
	fi

	mkdir -p $llogdir || exit 1

	$DEBUGFS -c -R "dump update_log $catlist" $mdt_dev

	if [[ ! -f $catlist ]] ; then
		echo "$PROG: $catlist wasn't retrieved"
	else
		read -r -d '' -a OPT_MDTS <<< $(hexdump -v -e '2/8 " %16x" 2/8 "\n"' $catlist |
						awk '{print "[0x"$2":0x"$1":0x0]"}')

		length=${#OPT_MDTS[@]}
		(( ${#OPT_MDTIDX[@]} > 0 )) || OPT_MDTIDX=($(seq 0 $((length - 1))))
		echo "Selected MDTS: ${OPT_MDTIDX[*]}"
		for i in ${OPT_MDTIDX[@]} ; do
			local catfid=${OPT_MDTS[$i]}
			local dstcat=$llogdir/catlog$i.$catfid
			local dstdir=$llogdir/catlog${i}_llogs

			if (( $i >= $length)) ; then
				echo "skip wrong index $i, total $length MDTs"
				continue
			fi

			echo "Getting MDT$i llog catalog $catfid to $dstcat"
			$DEBUGFS -c -R "dump update_log_dir/$catfid $dstcat" $mdt_dev
			if [[ ! -f $dstcat ]] ; then
				echo "$PROG: llog catalog #$i wasn't received."
				continue
			fi
			if [[ ! $(which $LLOG_READER 2>/dev/null) ]] ; then
				echo "$PROG: no $LLOG_READER, skip plain llogs"
				continue
			fi
			if (( $(stat -c %s $dstcat) >= 8192 )) ; then
				mkdir -p $dstdir
				while read -r plain ; do
					local dstplain=$dstdir/${plain##*/}

					echo "Save $plain to $dstplain"
					$DEBUGFS -c -R "dump $plain $dstplain" $mdt_dev
				done < <(llog_reader $dstcat |
					 awk -F "path=" '/path=/ { print $2 }')
			else
				echo "$PROG: $dstcat is too small."
			fi
		done
	fi
}

if [ -z $OPT_DEV ] ; then
	echo "Mount is not specified, exiting"
	exit 1
fi
collect_updatelog