Hi, >>> I'm a bit concerned about things inadvertently breaking if we return an empty list for the well known LUNs. > > >> According to SPC we shall report an empty list if there is no well-known LUNS. >> FreeBSD has the same logic in REPORT LUNS handling. SCST does not support SELECT_WELLKNOWN case at all. >> >> I don't know the history of the existing behaviour to send always LUN0 instead of empty list. Probably it was >> for the SCSI_SELECT_ALL_ACCESSIBLE(0x02) case, where SPC allows LUN0. My patch keeps it for the 0x00, 0x02, 0x11 cases. >> Thus, I believe it does not break the backward compatibility. >Will this change require users to update their LUN configuration? Some >initiator operating systems require presence of a dummy LUN 0. Although >I agree that it is cleaner not to provide a hardcoded LUN 0, I think >Martin is concerned about this patch potentially breaking existing >configurations and causing frustration among LIO users. No reconfiguration on initiator side is required. W-LUN is a specific LUN for the specific SCSI target device that is well known for the Initiator. Generic Linux TCM does not have W-LUNs. Some storage systems based on Linux TCM may have W-LUNs. But then they shall / already have its own handling of REPORT LUNS command. Basically, it is an error to report LUN0 as W-LUN for the Initiator that expects some other numbers. BR, Dmitry
