On May 07, 2007  13:58 -0700, Andrew Morton wrote:

Final point: it's fairly disappointing that the present implementation is
ext4-only, and extent-only.  I do think we should be aiming at an ext4
bitmap-based implementation and an ext3 implementation.

Actually, this is a non-issue.  The reason that it is handled for extent-only
is that this is the only way to allocate space in the filesystem without
doing the explicit zeroing.  For other filesystems (including ext3 and
ext4 with block-mapped files) the filesystem should return an error (e.g.
-EOPNOTSUPP) and glibc will do manual zero-filling of the file in userspace.

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