On Fri, Jul 27, 2007 at 03:07:14PM +1000, David Chinner wrote:

quoted

It duplicates fs/mpage.c in bio building and introduces new generic API
(iomap, map_blocks_t, etc).

Using a new API for new functionality is a bad thing?

Depends on wht you do.  This patch is just a quickhack to shoe-horn
delalloc support into ext4.  Introducing a new abstraction is overkill.
If we really want an overhaul of the writeback path that's extent-aware,
and efficient for delalloc and unwritten extents introducing a proper
iomap-like data structure would make sense.  That beeing said I personally
hate the ubffer_head abuse for bmap data that we have in various places
as it's utterly confusing and wasting stack space, but that's a different
discussion.