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    SubjectRe: [PATCH 0/5] fallocate system call
    On Sun, Apr 29, 2007 at 10:25:59PM -0700, Chris Wedgwood wrote:
    > 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?
    >
    > 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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