shelf_disks

#!/usr/bin/perl

# trying to establish mapping between physical drive number in given shelf and linux logical device name

die "Usage: shelf_disks /dev/sgX [--sg]" if !defined $ARGV[0];

$dev = $ARGV[0];
my $sg = 0;
$sg = 1 if defined $ARGV[1] && $ARGV[1] eq '--sg';

# building list of SAS addresses on shelf
open SES, "sg_ses -p 0xA $dev 2>/dev/null |" || die "sg_ses start failed";

$disk = -1;
while (<SES>) {
    chomp;

    $disk++ if /Transport protocol/;
    $sas{$disk} .= " $1" if /^\s*SAS address: (0x[0-9a-f]+)\s*$/;
}

close SES;

# find SAS ddresses of visible disks
# /sys/class/sas_device/end_device-1:2:6/device/target1:0:7/1:0:7:0
$base = "/sys/class/sas_device";
foreach $dev (glob ("$base/*")) {
    next unless -e "$dev/sas_address";

    if ($sg) {
        foreach $tgt (glob ("$dev/device/target*/*")) {
            next unless $tgt =~ /\/(\d+:\d+:\d+:\d+)$/;

            foreach $block (glob ("$tgt/scsi_generic:*")) {
                next unless $block =~ /\/scsi_generic:(.+)$/;
                $name = $1;
                $sas = `cat $dev/sas_address`;
                chomp $sas;
                $addr{$sas} = $name;
            }
        }
    } else {
        foreach $tgt (glob ("$dev/device/target*/*")) {
            next unless $tgt =~ /\/(\d+:\d+:\d+:\d+)$/;

            foreach $block (glob ("$tgt/block:*")) {
                next unless $block =~ /\/block:(.+)$/;
                $name = $1;
                $sas = `cat $dev/sas_address`;
                chomp $sas;
                $addr{$sas} = $name;
            }
        }
    }
}


foreach $disk (sort {$a <=> $b} keys(%sas)) {
    $dev = "";
    foreach $sas (split / +/, $sas{$disk}) {
        $dev .= " /dev/".$addr{$sas} if defined $addr{$sas};
    }
    
    print "$disk:\t$dev\n";
}