Description of problem:
On a RHEL4.8 host, it has been seen that "multipath -v3" displays tgt_node_name as blank.

===== path info sdaa (mask 0x1f) =====
bus = 1
dev_t = 65:160
size = 41943040
vendor = NETAPP
product = LUN
rev = 7310
h:b:t:l = 48:0:0:5
tgt_node_name =
serial = HnSwO4QIhOTq
path checker = readsector0 (controler setting)
state = 2
getprio = /sbin/mpath_prio_netapp /dev/%n (controler setting)
prio = 2
getuid = /sbin/scsi_id -g -u -s /block/%n (controler setting)
uid = 360a98000486e53774f345149684f5471 (callout)
path sdab not found in pathvec

The reason for this is that multipath looks in sysfs at a hardcoded FC path. Following is the code snippet from libmultipath/discovery.c file.
  */
        if(safe_sprintf(attr_path,
                        "%s/class/fc_transport/target%i:%i:%i/node_name",
                        sysfs_path,
                        curpath->sg_id.host_no,
                        curpath->sg_id.channel,
                        curpath->sg_id.scsi_id)) {
                condlog(0, "attr_path too small");
                return 1;
        }

Here, path is being assigned as %s/class/fc_transport/target%i:%i:%i/node_name. For an iscsi device, we need to look at %s/class/iscsi_transport/target%i:%i:%i/target_name.

Version-Release number of selected component (if applicable):
device-mapper-multipath-0.4.5-35.el4

How reproducible:
Always

Steps to Reproduce:
1.Map some iscsi LUNs to the host
2.Run multipath -v3
  
Actual results:
No value is displayed for tgt_node_name

Expected results:
multipath -v3 should display correct target name.