dmapi vs. filesystem filter drivers

[John Groves <jgl@xxxxxxxxxxxxxx>]

Some time ago on this list I recall seeing some discussion of dmapi vs. 
filesystem filter drivers, and I think somebody said that the linux 
filesystem interface was being redesigned to provide reasonable support 
for filter drivers.
Can anybody confirm whether a filter driver interface will be supported, 
and point me to more information on the status of that work?
Thanks,
John