Re: [patch] 512-byte alignment for O_DIRECT I/O

[Andrew Morton <akpm@digeo.com>]

Steve Lord wrote:
> 
> On Mon, 2002-10-07 at 17:59, Andrew Morton wrote:
> >
> > This patch from Badari is passing all testing now.
> >
> .....
> > +++ 2.5.41-akpm/fs/xfs/linux/xfs_aops.c       Mon Oct  7 15:50:21 2002
> > @@ -688,8 +688,8 @@ linvfs_direct_IO(
> >  {
> >       struct inode *inode = file->f_dentry->d_inode->i_mapping->host;
> >
> > -        return generic_direct_IO(rw, inode, iov, offset, nr_segs,
> > -                                     linvfs_get_blocks_direct);
> > +        return generic_direct_IO(rw, inode, inode->i_sb->s_bdev,
> > +                     iov, offset, nr_segs, linvfs_get_blocks_direct);
> >  }
> >
> >  STATIC int
> >
> 
> Actually this part is broken for XFS - it will work for most cases,
> but not for realtime files, in this case there is another bdev involved.
> I just have to work out how to get to it from here...... the getblock
> code knows enough to set it in the bh, but at this level we do not.
> 

Well we can pass in NULL for the while, get the old behaviour.

But yes, I'd prefer to only ever use the get_block() value.  It's
really messy though - things like deferring the check of the aligment
of all the iovec segments until we've run get_block...

Maybe we should ask the caller to pass in the alignment itself,
just 512, 2048, etc?