On Monday, December 10, 2018 at 5:52:19 PM UTC-8, Satyajit Deshmukh wrote:
>
> Hello,
>
> We are fairly frequently now running into this. Looks like an issue with
> the sysfs interface.
>
> iscsi_sysfs_get_blockdev_from_lun() sometimes does not find the SCSI block
> device (say /dev/sdd) for a logged in iSCSI target.
>
> Thus, iscsiadm -m session -P0 does not print the SCSI device block path
> (say /dev/sdd)
>
> From code walk-through, I can see there are 2 places, where it can happen.
> Sharing that here.
>
> diff -uNr open-iscsi-2.0.874/usr/iscsi_sysfs.c
> open-iscsi-2.0.874_2/usr/iscsi_sysfs.c
> --- open-iscsi-2.0.874/usr/iscsi_sysfs.c 2018-11-19 19:25:38.935602682
> +0000
> +++ open-iscsi-2.0.874_2/usr/iscsi_sysfs.c 2018-11-19 19:43:08.214013706
> +0000
> @@ -1557,19 +1557,24 @@
> snprintf(id, sizeof(id), "%d:0:%d:%d", host_no, target, lun);
> if (!sysfs_lookup_devpath_by_subsys_id(devpath, sizeof(devpath),
> SCSI_SUBSYS, id)) {
> - log_debug(3, "Could not lookup devpath for %s %s",
> + log_error("Could not lookup devpath for %s %s",
> SCSI_SUBSYS, id);
> return NULL;
> }
> + log_debug(0, "devpath is %s for id %s", devpath, id);
>
>
> sysfs_len = strlcpy(path_full, sysfs_path, sizeof(path_full));
> if (sysfs_len >= sizeof(path_full))
> sysfs_len = sizeof(path_full) - 1;
> strlcat(path_full, devpath, sizeof(path_full));
>
> + log_debug(0, "path_full is %s", path_full);
> dirfd = opendir(path_full);
> - if (!dirfd)
> + if (!dirfd) {
> + log_error("Could not open sysfs dir %s",
> + path_full);
> return NULL;
> + }
>
> while ((dent = readdir(dirfd))) {
> if (!strcmp(dent->d_name, ".") || !strcmp(dent->d_name, ".."))
>
>
> Are there such known issues with the sysfs where device paths are not
> found, for logged in targets?
> Any pointers/suggestions on debugging this greatly appreciated.
> We too are trying to root-cause and would share our finding here.
>
> Thanks,
> Satyajit
>
>
>
>
> Based on the code, I'm not sure it should always be considered an error
when no block device is found, so I'm not comfortable changing the code to
assume this.
I believe the path created depends on the target. For example, for a tape
device target, there will be no block device.
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