On Thu, Mar 01, 2007 at 10:44:16PM +0000, Dave Kleikamp wrote:

Would EINVAL (or whatever) make it back to the caller of
posix_fallocate(), or would glibc fall back to its current
implementation?

Forgive me if I haven't put enough thought into it, but would it be
useful to create a generic_fallocate() that writes zeroed pages for any
non-existent pages in the range?  I don't know how glibc currently
implements posix_fallocate(), but maybe the kernel could do it more
efficiently, even in generic code.  Maybe we don't care, since the major
file systems can probably do something better in their own code.

I'd be more happy to have the write out zeroes loop in glibc.  And
glibc needs to have it anyway, for older kernels.