Re: [Qemu-devel] [PATCH 09/26] ide: Set BSY bit during FLUSH

[Alex Williamson]

On Wed, 2013-07-03 at 15:16 -0500, Michael Roth wrote:
> On Wed, Jul 3, 2013 at 3:10 PM, Alex Williamson
> <address@hidden> wrote:
> > On Wed, 2013-06-12 at 16:41 -0500, Michael Roth wrote:
> >> From: Andreas Färber <address@hidden>
> >>
> >> The implementation of the ATA FLUSH command invokes a flush at the block
> >> layer, which may on raw files on POSIX entail a synchronous fdatasync().
> >> This may in some cases take so long that the SLES 11 SP1 guest driver
> >> reports I/O errors and filesystems get corrupted or remounted read-only.
> >>
> >> Avoid this by setting BUSY_STAT, so that the guest is made aware we are
> >> in the middle of an operation and no ATA commands are attempted to be
> >> processed concurrently.
> >>
> >> Addresses BNC#637297.
> >>
> >> Suggested-by: Gonglei (Arei) <address@hidden>
> >> Signed-off-by: Andreas Färber <address@hidden>
> >> Signed-off-by: Kevin Wolf <address@hidden>
> >> Signed-off-by: Stefan Hajnoczi <address@hidden>
> >> (cherry picked from commit f68ec8379e88502b4841a110c070e9b118d3151c)
> >>
> >> Signed-off-by: Michael Roth <address@hidden>
> >> ---
> >>  hw/ide/core.c |    1 +
> >>  1 file changed, 1 insertion(+)
> >>
> >> diff --git a/hw/ide/core.c b/hw/ide/core.c
> >> index c7a8041..9926d92 100644
> >> --- a/hw/ide/core.c
> >> +++ b/hw/ide/core.c
> >> @@ -814,6 +814,7 @@ void ide_flush_cache(IDEState *s)
> >>          return;
> >>      }
> >>
> >> +    s->status |= BUSY_STAT;
> >>      bdrv_acct_start(s->bs, &s->acct, 0, BDRV_ACCT_FLUSH);
> >>      bdrv_aio_flush(s->bs, ide_flush_cb, s);
> >>  }
> >
> > This caused a regression for me from 1.5.0->1.5.1.  Windows 7 x64 no
> > longer boots on q35 IDE with this change.  Thanks,
> 
> Are you seeing the issue for upstream builds as well?

Yes, I bisected this on upstream.  If i revert just this from 1.5.1, I
can boot again.  Upstream requires reverting this and a workaround for
9afce429.  Thanks,

Alex