Re: LibPATA code issues / 2.6.15.4

[Mark Lord <lkml@rtr.ca>]

Mark Lord wrote:
> > Mark Lord wrote:
> >
> > > > sdb: Current: sense key: Medium Error
> > > >     Additional sense: Unrecovered read error - auto reallocate failed
> > > > end_request: I/O error, dev sdb, sector 398283329
> > > > raid1: Disk failure on sdb2, disabling device.
> > > >         Operation continuing on 1 devices
> ..
> > > The command failing above is SCSI WRITE_10, which is being
> > > translated into ATA_CMD_WRITE_FUA_EXT by libata.
> > >
> > > This command fails -- unrecognized by the drive in question.
> > > But libata reports it (most incorrectly) as a "medium error",
> > > and the drive is taken out of service from its RAID.
> > >
> > > Bad, bad, and worse.

.. hold off on 2.6.16 because of this or not?

> Well, no doubt whatsoever about it being a "regression",
> since the FUA code is *new* in 2.6.16 (not present in 2.6.15).
>
> The FUA code should either get fixed, or removed from 2.6.16.

Actually, now that I've done a little more digging, this FUA stuff
is inherently dangerous as implemented.  A least a few SATA controllers
including pipelines and whatnot that rely upon recognizing the (S)ATA
opcodes being using.  And I sincerely doubt that any of those will
recognize the very newish (and aptly named..) FUA opcodes.

These may be unsafe in general, unless we tag controllers as
FUA-capable and NON-FUA-capable, in addition to tagging the drives.

:/
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