Re: posix_fallocate question again

[Andrew Morton]

"Chen, Kenneth W" <kenneth.w.chen@xxxxxxxxx> wrote:
>
> This has been brought up by Ulrich more than 3 years ago:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=95569775802945&w=2

A decent fallocate() implementation requires that the underlying fs has a
permanent representation of blocks which are in an "allocated,
uninitialised" state.  afaik XFS is the only such filesystem.

It's a fair bit of work for what doesn't really sound a very useful
feature.  Doing it in libc is reasonable.  Probably the libc implementation
could be improved by using ioctl(FIBMAP) and O_DIRECT to mimimise IO and
CPU utilisation.

> Is there anytime soon that kernel 2.6 will have such functionality?

Nope.

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