On Wed, 2017-01-25 at 15:38 +0100, Hannes Reinecke wrote: > On 01/25/2017 03:27 PM, Ewan D. Milne wrote: > > On Wed, 2017-01-25 at 11:38 +0100, Hannes Reinecke wrote: > > > On 01/25/2017 11:23 AM, Christoph Hellwig wrote: > > > > On Wed, Jan 25, 2017 at 08:26:05AM +0100, Hannes Reinecke > > > > wrote: > > > > > For any device with an older SCSI revision we might not > > > > > be scanning VPD pages, which results in a wrongly configured > > > > > discard mode if thin provisioned is enabled. > > > > > According to sbc3 any thin provisioned device (ie devices > > > > > which have the LBPME bit set in the output of READ > > > > > CAPACITY(16)) need to support VPD pages. So this patch always > > > > > enables VPD pages even for older SCSI revisions if thin > > > > > provisioning is enabled. > > > > > > > > Can you explain what you need this for? A device with a per > > > > -SBC3 revision that wants us to use UNMAP? > > > > > > > Some storage arrays essentially lie about the SCSI revision (most > > > notably Hitachi :-), and some claim to support SPC-2 (or even > > > SPC) but support newer features, too. Most notably VPD pages > > > support. In this case it was an HP EVA claiming to support SPC-2 > > > only, but providing thin provisioning. > > > > Um, isn't this why we added: > > > > commit c1d40a527e885a40bb9ea6c46a1b1145d42b66a0 > > Author: Martin K. Petersen <martin.petersen@xxxxxxxxxx> > > Date: Tue Jul 15 12:49:17 2014 -0400 > > > > scsi: add a blacklist flag which enables VPD page inquiries > > > > (well, it was for storvsc, but we could add an entry for the HP > > EVA) > > > I knew someone would raise this objection :-) > > Thing is, setting 'WS16' here is arguably wrong, as LPBME just means > 'logical block provisioning management enabled', not 'WRITE SAME 16 > with UNMAP' supported. > > And we've set the restriction for scanning VPD pages rather high by > moving it to at least SPC-3; meaning we lose out on all SPC-2 devices > with logical block provisioning. > > So rather than blacklisting each and every device (and incurring > loads of customer calls) I'd rather fix it once and for all. Anything with a capacity over 2TB gets into RC16 .,. that includes a lot of USB storage nowadays. What would this proposed addition do to them? James -- 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
