Re: [PATCH 1/3] bdi: Use parent filesystem BDI for inodes notcapable of writeback

[Jan Kara]

On Tue 27-07-10 16:21:29, Christoph Hellwig wrote:
> On Tue, Jul 27, 2010 at 04:12:07PM -0400, Christoph Hellwig wrote:
> > On Tue, Jul 27, 2010 at 08:01:31PM +0200, Jan Kara wrote:
> > > > It shouldn't.  Block device nodes are on the bdev filesystems, and
> > >   Ok, so inode->i_sb->s_bdi will actually point to noop_backing_dev_info
> > > as set by set_anon_super(). Or am I completely out?
> > 
> > I think you're right.  This seems rather bad if it's indeed true. I'll
> > quickly verify it using Dave's new tracing once I've built a block
> > tree kernel.
> 
> Indeed it does.  So using ->s_bdi actually is wrong for the block
> device node, given that it does set up the bdevfs inode's 
> backing_dev_info to the proper one, but can't actually do it for
> the per-sb one.
  Yes. So what I do in inode_to_bdi() is necessary (although I agree it
looks a bit ugly).
								Honza
-- 
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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