>>>>> "Doug" == Douglas Gilbert <dgilbert@xxxxxxxxxxxx> writes: Doug, Doug> SCSI WRITE SAME does have one interesting quirk that Martin may Doug> like to consider. If the "number of logical blocks" field is zero, Doug> then that implies write to the end of the LU!! Madness when you Doug> think about it. libata's SCSI WRITE SAME translation takes the Doug> zero number of LBs literally and does nothing I guess (when the Doug> UNMAP bit is given). Yeah. Writing the whole device is one of my pet peeves. Furthermore, there are a bunch of devices that have an internal cap on the number of blocks per WRITE SAME command that isn't advertised anywhere. Said cap is lower than the 32-bit block range permitted by WRITE SAME(16). And said cap sometimes also applies to the end-of-device case. I.e. a block count of 0 only works if you're close enough to the end. Grrr! Meanwhile elsewhere the proposal to advertise WRITE SAME limits in the b0 VPD was gunned down in T10. I ranted about this situation at length in Boston. Too bad you couldn't make it... Anyway. We're already bending SBC a bit for our internal use between sd and libata-scsi. So I don't consider the "mishandling" of the 0 block length a problem. sd would never issue a 0-length WS anyway. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
