Re: O_DIRECT, ext3fs, kernel 2.4.32... again

From: Nathan Scott
Date: Mon May 01 2006 - 17:28:25 EST


On Mon, May 01, 2006 at 01:23:03PM +0200, DervishD wrote:
> Hi Marcelo :)
>
> * Marcelo Tosatti <marcelo@xxxxxxxxx> dixit:
> > > Shouldn't ext3fs return an error when the O_DIRECT flag is
> > > used in the open call? Is the open call userspace only and thus
> > > only libc can return such error? Am I misunderstanding the entire
> > > issue and this is a perfectly legal behaviour (allowing the open,
> > > failing in the read operation)?
> >
> > Your interpretation is correct. It would be nicer for open() to
> > fail on fs'es which don't support O_DIRECT, but v2.4 makes such
> > check later at read/write unfortunately ;(
>
> Oops :(

Nothing else really make sense due to fcntl...
fcntl(fd, F_SETFL, O_DIRECT);
...can happen at any time, to enable/disable direct I/O.

cheers.

--
Nathan
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