Il 15/11/2012 21:01, Elliott, Robert (Server Storage) ha scritto: > WRITE SAME always has a payload, regardless of the UNMAP bit value. > > For WRITE SAME with UNMAP=0, it's extremely important; that's how > what to write is specified. > > For WRITE SAME with UNMAP=1, the device server is required to check > that the payload matches the data that is returned for unmapped LBAs. > lf LBPRZ=1 (read zeros for unmapped LBAs), that means checking that > the payload has all zeros. In sbc3r33, this rule is tucked away in > model section 4.7.3.4.3, not the command section 5.41.
Does that mean that LBPRZ=0, LPBWS=1 is practically an invalid combination? Because there's no real way for the device server to perform the check successfully. Paolo > I would like to change that rule (it's a nuisance and a performance > burden), but that's the current rule going into SBC-3 letter ballot. > > Changing WRITE SAME with UNMAP=1 to ignore the payload would provide > essentially the same functionality as changing the UNMAP command to > be mandatory, not just a hint; both approaches have been discussed. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
