#!/usr/bin/perl -w
# $Header: /cvsroot/lustre-tools/src/read-inodes,v 1.2 2011/03/16 00:04:17 jrappley Exp $

use strict;
use File::Basename;
use Getopt::Long;
use Pod::Usage;
use POSIX qw(ceil);
use Fcntl 'SEEK_SET';

my $progname = basename $0;

# Globals

my $group = 0;
my $inodesPerGroup = 0;
my $inodeBlocksPerGroup = 0;
my @usedInodes;

my $freeIBlocks = 0;

# Command line options
my %arg;
$arg{verbose} = 0;

sub dprint {
    if ($arg{verbose} > 1) {
	print @_;
    }
}

# Parse command line options
Getopt::Long::Configure("bundling");

GetOptions(
	   "h|help"       => \$arg{h},
	   "d|device=s"   => \$arg{device},
	   "m|meta=s"     => \$arg{meta},
	   "v|verbose+"   => \$arg{verbose},
) or pod2usage(-exitval => 2,
		 -verbose => 1);

pod2usage(1) if ($arg{h});

pod2usage(1) if (scalar(@ARGV) != 0);

pod2usage(1) if (! defined $arg{meta});

if (defined $arg{device}) {
    open D, "<", "$arg{device}" or die "Couldn't open $arg{device}: $!";
}

open M, "<", $arg{meta} or die "Couldn't open $arg{meta}: $!";

while (<M>) {
    if (/Inodes per group:\s+(\d+)/) {
	$inodesPerGroup = $1;
    } elsif (/Inode blocks per group:\s+(\d+)/) {
	$inodeBlocksPerGroup = $1;
    } elsif (/^$/) {
	last;
    }
}

if ($inodesPerGroup == 0 || $inodeBlocksPerGroup == 0) {
    print STDERR "Couldn't determine number of inodes per group, exiting\n";
    exit 1;
}

my $inodesPerBlock = $inodesPerGroup / $inodeBlocksPerGroup;
my $firstItableBlock;

while (<M>) {
    if (/^Group (\d+)/) {
	$group = $1;
    }

    if (/Inode table at (\d+)/) {
	$firstItableBlock = $1;
    }

    if (/(\d+) free inodes/) {
	$usedInodes[$group] = $inodesPerGroup - $1;
    }

    if (/Free inodes:\s(.*)/) {
	# next if $group > 1;
	my @usedIBlocks;
	my $groupFreeIBlocks = 0;
	for my $i (0..$inodeBlocksPerGroup - 1) {
	    $usedIBlocks[$i] = $inodesPerBlock;
	}
	dprint "$group: ", join(" ", @usedIBlocks), "\n";
	my @irange = split(/, /, $1);
	dprint "Group $group: ", join(" X ", @irange), "\n";

	foreach my $range (@irange) {
	    dprint "range: $range\n";
	    if ($range =~ /(\d+)-(\d+)/) {
		my $low = $1 - ($group * $inodesPerGroup);
		my $high = $2 - ($group * $inodesPerGroup);
		dprint "marking $low..$high\n";
		for my $inum ($low..$high) {
		    my $iBlock = ceil($inum / $inodesPerBlock) - 1;
		    dprint "inum $inum block $iBlock\n";
		    $usedIBlocks[$iBlock]--;
		}
	    } else {
		my $inum = $range - ($group * $inodesPerGroup);
		my $iBlock = ceil($inum / $inodesPerBlock) - 1;
		dprint "marking $inum block $iBlock\n";
		$usedIBlocks[$iBlock]--;
	    }
	}

	for my $i (0..$#usedIBlocks) {

	    if ($usedIBlocks[$i] == 0) {
		$groupFreeIBlocks++;
		my $block = $firstItableBlock + $i;
		if (0) {
		    dprint "group $group read ", $firstItableBlock + $i, "\n";
		    sysseek(D, $block * 4096, SEEK_SET);
		    sysread(D, my $foo, 4096);
		}
	    } elsif (defined $arg{device}) {
		my $block = $firstItableBlock + $i;
		dprint "group $group read ", $firstItableBlock + $i, "\n";
		sysseek(D, $block * 4096, SEEK_SET);
		sysread(D, my $foo, 4096);
	    }
	}
	$freeIBlocks += $groupFreeIBlocks;

	my @blockStr = map { sprintf "%3d", $_ } @usedIBlocks;
	if ($arg{verbose}) {
	    printf("%6d: %3d/%3d | %s\n",
		   $group,
		   $usedInodes[$group],
		   $groupFreeIBlocks,
		   join("", @blockStr));
	}
    }
}

print "Unused inode blocks: $freeIBlocks\n";

close M;

__END__

=head1 NAME

=head1 SYNOPSIS

skeleton.pl [-h]

=head1 DESCRIPTION

=head1 OPTIONS

=over 8

=item B<-h|--help>

Print a help message and exit.

=back 8

=head1 EXAMPLES

=head1 ENVIRONMENT

=over 8

=item B<FOO>

FOO is an environment variable that somehow alters the execution of
this program.

=back 8

=head1 KNOWN BUGS

=head1 CAVEATS

=head1 DETAILS

=head1 REPORTING BUGS

=head1 AUTHOR

=head1 SEE ALSO