Re: ->direct_IO API change in current 2.4 BK

[Marcelo Tosatti]

On Wed, 9 Jul 2003, Andreas Dilger wrote:

> On Jul 09, 2003  13:31 +0100, Christoph Hellwig wrote:
> > I just got a nice XFS oops due to the direct_IO API change in
> > 2.4.  Guys, this is a STABLE series and APIs are supposed to be exactly
> > that, _STABLE_.  If you really think O_DIRECT on NFS is soo important
> > please add a ->direct_IO2 for NFS like the reiserfs read_inode2 hack.
>
> I would have to agree with that sentiment - we shouldn't change the
> API in an "almost compatible" way, although I would have hoped that
> compile warnings and/or module symbol versioning would have avoided
> a crash.
>
> > But what's the use of it anyway?  AFAIK it's mostly for whoracle setups
> > that have their data on netapps but that needs a certified vendor kernel
> > not mainline..
>
> Actually, it is useful for Lustre to do this, because it allows us to have
> a file handle (which, naturally, holds per-file data) at the time the IO is
> sent over the wire, instead of the "anonymous" writes that happen now.
> This helps us with readahead on the server and other minor improvements.

Fine, I agree. Trond, I'll have to revert your direct IO patches because
they break the _stable_ API, indeed.

Please come up with another solution for the problem (->direct_IO2 ? its
ugly, but...).