Re: O_DIRECT support in ext3?

[Andrew Morton]

Andreas Dilger wrote:
> 
> On Aug 13, 2002  15:48 +0200, Roy Sigurd Karlsbakk wrote:
> > playing around with O_DIRECT, I really _can't_ make it work on ext3?
> >
> > why is this?
> 
> Because O_DIRECT needs a specific o_direct I/O method that has not yet
> been written for ext3.  I believe only ext2 and reiserfs support it
> right now.  I will eventually need to add support for this, but it is
> not yet high on my list of priorities.  Maybe someone else will beat
> me to it.

Yes, we need to get it up and running for 2.5.  It should be relatively
straightforward.  It'll need an ext3_get_blocks_for_o_direct() which
does a journal_start/stop if create=1.

And maybe some fancy footwork around invalidating existing pagecache in
ext3_file_write(), but the current code looks to be OK actually.

It shouldn't be a big deal; mainly testing.