[src/trunk]: src/sys/dev/ata account for already transferred data (partially ...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/669bcfc7ea57
branches:  trunk
changeset: 1010407:669bcfc7ea57
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Sun May 24 22:12:29 2020 +0000

description:
account for already transferred data (partially done I/O) when
retrying an xfer, to avoid reading/writing data from/to wrong offset,
and eventually beyond the end of data buffer

fixes data corruption under QEMU observed by Paul Ripke for emulated
IDE drives

diffstat:

 sys/dev/ata/wd.c |  18 +++++++++++++-----
 1 files changed, 13 insertions(+), 5 deletions(-)

diffs (54 lines):

diff -r 179cb599c91c -r 669bcfc7ea57 sys/dev/ata/wd.c
--- a/sys/dev/ata/wd.c  Sun May 24 21:09:49 2020 +0000
+++ b/sys/dev/ata/wd.c  Sun May 24 22:12:29 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: wd.c,v 1.462 2020/04/13 10:49:34 jdolecek Exp $ */
+/*     $NetBSD: wd.c,v 1.463 2020/05/24 22:12:29 jdolecek Exp $ */
 
 /*
  * Copyright (c) 1998, 2001 Manuel Bouyer.  All rights reserved.
@@ -54,7 +54,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: wd.c,v 1.462 2020/04/13 10:49:34 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: wd.c,v 1.463 2020/05/24 22:12:29 jdolecek Exp $");
 
 #include "opt_ata.h"
 #include "opt_wd.h"
@@ -663,6 +663,7 @@
 wdstart1(struct wd_softc *wd, struct buf *bp, struct ata_xfer *xfer)
 {
        struct dk_softc *dksc = &wd->sc_dksc;
+       const uint32_t secsize = dksc->sc_dkdev.dk_geom.dg_secsize;
 
        KASSERT(bp == xfer->c_bio.bp || xfer->c_bio.bp == NULL);
        KASSERT((xfer->c_flags & (C_WAITACT|C_FREE)) == 0);
@@ -680,6 +681,14 @@
        xfer->c_bio.blkdone = 0;
        xfer->c_bio.bp = bp;
 
+       /* Adjust blkno and bcount if xfer has been already partially done */
+       if (__predict_false(xfer->c_skip > 0)) {
+               KASSERT(xfer->c_skip < xfer->c_bio.bcount);
+               KASSERT((xfer->c_skip % secsize) == 0);
+               xfer->c_bio.bcount -= xfer->c_skip;
+               xfer->c_bio.blkno += xfer->c_skip / secsize;
+       }
+
 #ifdef WD_CHAOS_MONKEY
        /*
         * Override blkno to be over device capacity to trigger error,
@@ -714,10 +723,9 @@
         * and needed by transfer offset or size.
         */
        if (wd->sc_flags & WDF_LBA48 &&
-           (((xfer->c_bio.blkno +
-            xfer->c_bio.bcount / dksc->sc_dkdev.dk_geom.dg_secsize) >
+           (((xfer->c_bio.blkno + xfer->c_bio.bcount / secsize) >
            wd->sc_capacity28) ||
-           ((xfer->c_bio.bcount / dksc->sc_dkdev.dk_geom.dg_secsize) > 128)))
+           ((xfer->c_bio.bcount / secsize) > 128)))
                xfer->c_bio.flags |= ATA_LBA48;
 
        /*