On Sun, Apr 29, 2007 at 10:25:59PM -0700, Chris Wedgwood wrote:

quoted text
> On Mon, Apr 30, 2007 at 10:47:02AM +1000, David Chinner wrote:

>

> > For FA_ALLOCATE, it's supposed to change the file size if we

> > allocate past EOF, right?

>

> I would argue no.  Use truncate for that.

I'm going from the ext4 implementation because the semantics

have not been documented yet.
IIRC, the argument for FA_ALLOCATE changing file size is that

posix_fallocate() is supposed to change the file size. I think

that having a mode for real preallocation and another for

posix_fallocate is a valid thing to do...
Note that the way XFS implements growing the file size after the

allocation is via a truncate....
> > For FA_DEALLOCATE, does it change the filesize at all?

quoted text
>

> Same as above.

>

> > Or does

> > it just punch a hole in the file?

>

> Yes.

That's would what I did because otherwise you'd use ftruncate64().

Without documented behaviour or an ext4 implementation, I have to

ask what it's supposed to do, though ;)
Cheers,
Dave.

--

Dave Chinner

Principal Engineer

SGI Australian Software Group

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