Description of problem:

The ext3_journalled_aops doesn't define .direct_IO. This causes applications
that have O_DIRECT in their open flags fail universally in any ext3 filesystem
mounted with "data=journal" mode due to the following checking in dentry_open()
called by sys_open -> filp_open route:

        /* NB: we're sure to have correct a_ops only after f_op->open */
        if (f->f_flags & O_DIRECT) {
                if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO) {
                        fput(f);
                        f = ERR_PTR(-EINVAL);
                }
        }


static struct address_space_operations ext3_writeback_aops = {
        .readpage       = ext3_readpage,
        .readpages      = ext3_readpages,
        .writepage      = ext3_writeback_writepage,
        .sync_page      = block_sync_page,
        .prepare_write  = ext3_prepare_write,
        .commit_write   = ext3_writeback_commit_write,
        .bmap           = ext3_bmap,
        .invalidatepage = ext3_invalidatepage,
        .releasepage    = ext3_releasepage,
        .direct_IO      = ext3_direct_IO,
};
                                                                                
static struct address_space_operations ext3_journalled_aops = {
        .readpage       = ext3_readpage,
        .readpages      = ext3_readpages,
        .writepage      = ext3_journalled_writepage,
        .sync_page      = block_sync_page,
        .prepare_write  = ext3_prepare_write,
        .commit_write   = ext3_journalled_commit_write,
        .set_page_dirty = ext3_journalled_set_page_dirty,
        .bmap           = ext3_bmap,
        .invalidatepage = ext3_invalidatepage,
        .releasepage    = ext3_releasepage,
};

Version-Release number of selected component (if applicable):


How reproducible:
Each time and everytime.


Steps to Reproduce:
1. Mount the filesystem with data=journal mode.
2. Write a test program with O_DIRECT in its flags.
3. Watch the open call return error with "invalid argument".
  
Actual results:


Expected results:


Additional info:
* I'm not really sure this is an oversignt or intentional.
* AS2.1 and RHEL 3 do not have this restriction.
* Upstream 2.6 kernel does *not* have this functionality either.