[Ocfs2-devel] [PATCH 4/6] Ext4: fail if we try to use hole punch

[Avi Kivity]

On 11/16/2010 02:50 PM, Josef Bacik wrote:
> On Tue, Nov 16, 2010 at 02:25:35PM +0200, Avi Kivity wrote:
> >  On 11/15/2010 07:05 PM, Josef Bacik wrote:
> >>  Ext4 doesn't have the ability to punch holes yet, so make sure we return
> >>  EOPNOTSUPP if we try to use hole punching through fallocate.  This support can
> >>  be added later.  Thanks,
> >>
> >
> >  Instead of teaching filesystems to fail if they don't support the
> >  capability, why don't supporting filesystems say so, allowing the fail
> >  code to be in common code?
> >
>
> There is no simple way to test if a filesystem supports hole punching or not so
> the check has to be done per fs.  Thanks,

Could put a flag word in superblock_operations.  Filesystems which 
support punching (or other features) can enable it there.

Or even have its own callback.

-- 
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