Re: Proposal and plan for ext2/3 future development work

[Joel Becker <Joel.Becker@oracle.com>]

On Thu, Jun 29, 2006 at 09:14:53PM -0400, Jeff Garzik wrote:
> Agreed overall, though specifically for delayed allocation I think 
> that's an ext4 thing:
> 
> * First off, I'm a big fan of delalloc, and (like extents) definitely 
> want to see the feature implemented
> * Delayed allocation, properly done, requires careful interaction with 
> VM writeback (memory pressure or normal writeout), and may require some 
> minor changes to generic code in fs/* and mm/*

	To be honest, I'd like to see more delayed allocation
infrastructure in the VFS itself.  XFS has to maintain an entire chunk
of state for it, and I suspect ext4 will as well.  I'd love to get
delayed allocation into OCFS2 someday.  Why not move to where we can
share the in-memory accounting code?
	Now, we'd probably want to start by prototyping it in ext4
directly.  Once it's stable as a filesystem feature, we can see where
XFS and ext4 overlap, etc, etc.  But I'd like to keep a more generic
direction in mind.

Joel

-- 

"The suffering man ought really to consume his own smoke; there is no 
 good in emitting smoke till you have made it into fire."
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Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker@oracle.com
Phone: (650) 506-8127