Re: [RFC] add FIEMAP ioctl to efficiently map file allocation

On May 02, 2007  00:20 +1000, David Chinner wrote:

My point was that there is a difference between specification and
implementation - if the specification says something is compulsory,
then they must be implemented in the filesystem. This is easy
enough to ensure by code review - we don't need additional interface
complexity for this....

What you seem to be missing about my proposal is that the FLAG_INCOMPAT
is for future use by that part of the specification we haven't thought
of yet...  Having COMPAT/INCOMPAT flags has been very useful for ext2/3/4,
and is much better than having version numbers for the interface.

Cheers, Andreas
--
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.