Messages in this thread | | | Date | Mon, 30 Apr 2007 15:56:32 +1000 | From | David Chinner <> | Subject | Re: [PATCH 0/5] fallocate system call |
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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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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