[sheepdog] [RFC PATCH] farm: don't check of the existing object before slice_write

Liu Yuan namei.unix at gmail.com
Tue Jul 23 14:01:52 CEST 2013


On Tue, Jul 23, 2013 at 06:00:14PM +0900, MORITA Kazutaka wrote:
> At Fri, 19 Jul 2013 13:17:53 +0800,
> Liu Yuan wrote:
> > 
> > On Fri, Jul 19, 2013 at 02:09:23PM +0900, MORITA Kazutaka wrote:
> > > At Fri, 19 Jul 2013 13:02:54 +0800,
> > > Liu Yuan wrote:
> > > > 
> > > > On Fri, Jul 19, 2013 at 01:33:16PM +0900, MORITA Kazutaka wrote:
> > > > > Currently, we stores sliced objects for the farm store, so
> > > > > sha1_file_exist() fails always.
> > > > > 
> > > > > Signed-off-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
> > > > > ---
> > > > > 
> > > > > Other approaches are:
> > > > > 
> > > > >  - Calculate the sha1 digest before slicing objects and store the
> > > > >    value to the farm store so that sha1_file_exist() can check it.
> > > > >
> > > > >  - Make sheep return the hash value of the sliced data.
> > > > > 
> > > > > Any suggestions?
> > > > 
> > > > I don't understand this patch. Does it solve any exsiting problem?
> > > > Why sha1_file_exist() will fail? Every object will have a unquie sha1 as
> > > > before after stored into farm.
> > > 
> > > Farm stores only sliced objects, no?  sd_read_object_sha1() calculates
> > > a sha1 digest against a whole object (not sliced data).
> > > 
> > 
> > Ah, I see the point. For a quick thought, there won't be many objects with the
> > same content in images, so removing pre-check looks fine.
> 
> Okay, then this patch can be applied without change?
> 

Applied, thanks

Yuan



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