Re: [PATCH] Cygwin: fsync: Fix EINVAL for block device.

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Jan 22 00:22, Takashi Yano wrote:
> On Sat, 21 Jan 2023 15:53:37 +0100
> Corinna Vinschen wrote:
> > Hi Takashi,
> > 
> > On Jan 21 21:44, Takashi Yano wrote:
> > > The commit af8a7c13b516 has a problem that fsync returns EINVAL for
> > > block device. This patch treats block devices as a special case.
> > > https://cygwin.com/pipermail/cygwin/2023-January/252916.html
> > > 
> > > Fixes: af8a7c13b516 ("Cygwin: fsync: Return EINVAL for special files.")
> > > Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
> > > ---
> > >  winsup/cygwin/fhandler/base.cc | 23 ++++++++++++++++++++++-
> > >  1 file changed, 22 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/winsup/cygwin/fhandler/base.cc b/winsup/cygwin/fhandler/base.cc
> > > index b2738cf20..fc0410522 100644
> > > --- a/winsup/cygwin/fhandler/base.cc
> > > +++ b/winsup/cygwin/fhandler/base.cc
> > > @@ -1725,10 +1725,31 @@ fhandler_base::utimens (const struct timespec *tvp)
> > >    return -1;
> > >  }
> > >  
> > > +static bool
> > > +is_block_device (_major_t major)
> > > +{
> > > +  switch (major)
> > > +    {
> > > +    case DEV_FLOPPY_MAJOR:
> > > +    case DEV_SD_MAJOR:
> > > +    case DEV_CDROM_MAJOR:
> > > +    case DEV_SD1_MAJOR:
> > > +    case DEV_SD2_MAJOR:
> > > +    case DEV_SD3_MAJOR:
> > > +    case DEV_SD4_MAJOR:
> > > +    case DEV_SD5_MAJOR:
> > > +    case DEV_SD6_MAJOR:
> > > +    case DEV_SD7_MAJOR:
> > > +      return true;
> > > +    }
> > > +  return false;
> > > +}
> > > +
> > 
> > You shouldn't need that. Just check S_ISBLK (pc.dev.mode ())
> 
> Thanks for the advice. I looked into the S_ISBLK macro and
> winsup/cygwin/devices.cc and noticed that S_ISBLK() returns
> true for tape device. Is this the right thing?

Oops, no.  Tape devices are supposed to be character devices.
I'll fix that.


Thanks,
Corinna