Messages in this thread | | | From | "K. Y. Srinivasan" <> | Subject | scanning for LUNs | Date | Thu, 4 Apr 2013 08:12:37 -0700 |
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Here is the code snippet for scanning LUNS (drivers/scsi/scsi_scan.c in function __scsi_scan_target()):
/* * Scan LUN 0, if there is some response, scan further. Ideally, we * would not configure LUN 0 until all LUNs are scanned. */ res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL); if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) { if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
So, if we don't get a response while scanning LUN0, we will not use scsi_report_lun_scan(). On Hyper-V, the scsi emulation on the host does not treat LUN0 as anything special and we could have situations where the only device under a scsi controller is at a location other than 0 or 1. In this case the standard LUN scanning code in Linux fails to detect this device. Is this behaviour expected? Why is LUN0 treated differently here. Looking at the scsi spec, I am not sure if this is what is specified. Any help/guidance will be greatly appreciated. Regards,
K. Y
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