Date: Wed, 28 Apr 1999 08:57:06 -0700 (PWT) From: Matthew Jacob <mjacob@feral.com> To: Joerg Wunsch <joerg_wunsch@uriah.heep.sax.de>, Juergen Lock <nox@jelal.kn-bremen.de> Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: QIC tape problems on -stable (was: hanging `tar xfvR /dev/nrst0' process, can i debug it?) Message-ID: <Pine.LNX.4.04.9904280852520.24720-100000@feral.com> In-Reply-To: <Pine.LNX.4.04.9904280824090.24720-100000@feral.com>
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> These are *amazingly* broken drives then. The SCSI specification says that
> a write of *zero* filemarks is to flush any pending writes. You have to do
> this when you do a read hardware position in order to avoid an ambiguity
> in the spec as to the true position as affected by data in the tape drive
> buffer. This is not an abstruse edge case in the SCSI spec. This is common
> sense as well. I believe that the writers of QIC f/w should be sent to
> Redmond for the rest of their miserable lives.
>
That said, try this patch:
*** scsi_sa.c.prev Wed Apr 28 08:54:12 1999
--- scsi_sa.c Wed Apr 28 08:56:43 1999
***************
*** 2723,2735 ****
{
struct scsi_tape_position_data loc;
union ccb *ccb;
! struct sa_softc *softc;
! int error;
/*
! * First flush any pending writes...
*/
! error = sawritefilemarks(periph, 0, 0);
/*
* The latter case is for 'write protected' tapes
--- 2723,2738 ----
{
struct scsi_tape_position_data loc;
union ccb *ccb;
! struct sa_softc *softc = (struct sa_softc *)periph->softc;
! int error = 0;
/*
! * First flush any pending writes (if any had occurred).
! * Amazingly stupid drives sometimes take a zero count
! * and say "Duh! Zero must mean One!".
*/
! if (softc->flags & SA_FLAG_TAPE_WRITTEN)
! error = sawritefilemarks(periph, 0, 0);
/*
* The latter case is for 'write protected' tapes
***************
*** 2739,2745 ****
if (error != 0 && error != EACCES)
return (error);
- softc = (struct sa_softc *)periph->softc;
ccb = cam_periph_getccb(periph, 1);
scsi_read_position(&ccb->csio, 1, sadone, MSG_SIMPLE_Q_TAG,
--- 2742,2747 ----
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