From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: [PATCH 0/4] Fiemap, an extent mapping ioctl - round 2
Date: Fri, 27 Jun 2008 11:32:52 +0100
Message-ID: <20080627103252.GA31765@shareable.org>
References: <20080625221835.GQ28100@wotan.suse.de> <4863A1C5.7020403@redhat.com> <20080627014119.GW29319@disturbed> <20080627094156.GA30200@shareable.org> <20080627100102.GB29319@disturbed>
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Dave Chinner wrote:
> On Fri, Jun 27, 2008 at 10:41:56AM +0100, Jamie Lokier wrote:
> > > > Right now the interface seems to be about returning details of the
> > > > filesystem's accounting of the on-disk layout, as opposed to just a
> > > > simple mapping.  As 2 examples:
...
> >    - The filesystem's internal representation may have _many_ more
> >      extents than the contiguous layout.  E.g. a 4GiB file might have
> >      65536 x 64kiB extents on some filesystem, or 1 extent when
> >      merged.  Is it ever useful to return the much larger list?
> 
> 64k max extent size? I'd consider that a block based filesystem,
> not an extent based filesytem....

It's only block based if the size is fixed.

Besides it's just an example.  If "real" extent based filesystems
never split their contiguous file extents for internal processing
reasons, I don't know what we're talking about :-)

-- Jamie