Re: O_DIRECT fails in some kernel and FS

[Steve Lord <lord@sgi.com>]

On Fri, 2002-02-01 at 14:44, Andrew Morton wrote:
> Ricardo Galli wrote:
> > 
> > After some comments from Oliver Diedrich (editor of heise.de), which told me
> > he couldn't make O_DIRECT work on 2.4.17, I tried with different versions and
> > file systems:
> > 
> > This is the result:
> > 
> > 2.4.14 - Ext[23] - redhat7.2 glibs: OK (at least the bytes are written)
> > 2.4.17 - ReiserFS - Debian Sid    : FAILS (0 bytes file, write returns -1)
> > 2.4.17 - Ext2 - Debian Woody      : OK (bytes written)
> > 2.4.17 - Ext3 - Debian Woody      : FAILS (0 bytes file, write returns -1)
> > 
> > Oliver Diedrich also told he could make work O_DIRECT with ext3 and 2.4.17.
> > 
> > Is this normal? Does it really work on 2.4.14? Or it doesn't but the kernel
> > doesn't avoid caching?
> > 
> 
> ext2 is the only filesystem which has O_DIRECT support.

And XFS ;-)

Steve