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Re: D_LOOKUP in REAL_LOOKUP?

To: krushnaal pai <krisonearth@xxxxxxxxx>
Subject: Re: D_LOOKUP in REAL_LOOKUP?
From: pradeep singh <pradeep.rautela@xxxxxxxxx>
Date: Fri, 3 Apr 2009 16:45:41 +0530
Cc: kernelnewbies@xxxxxxxxxxxx
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On Tue, Mar 31, 2009 at 11:31 AM, krushnaal pai <krisonearth@xxxxxxxxx> wrote:
> in kernel 2.6.11
> to retrieve a particular file the kernel calls d_lookup to check cache but
> if  it is not found in dcache ,kernel calls real_lookup to search the hard
> disk.
> however inside real_lookup the kernel again calls d_lookup . can someone plz
> explain why?

Because while you were waiting/sleeping for semaphore to be acquired.
Someone else might have actually read the contents into dentry cache.
So, why do a lookup!

Just to speed things up, it is a clever trick.

Comments tell it.

Thanks,
   --Pradeep
>



-- 
Pradeep

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