From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nick Piggin <npiggin@suse.de>
Subject: Re: Why do fs outside regular namespace clear DCACHE_UNHASHED?
Date: Mon, 1 Jun 2009 13:23:15 +0200
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References: <20090528071441.GE6920@wotan.suse.de> <E1M9e1M-0004Ch-J7@pomaz-ex.szeredi.hu>
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Cc: linux-fsdevel@vger.kernel.org
To: Miklos Szeredi <miklos@szeredi.hu>
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On Thu, May 28, 2009 at 01:43:40PM +0200, Miklos Szeredi wrote:
> On Thu, 28 May 2009, Nick Piggin wrote:
> > Please humour a relative vfs/procfs newbie... Why do filesystems insist that
> > a dentry must be !DCACHE_UNHASHED in order to work in /proc/pid/fd/? I can't
> > find the code that checks this, and pipefs fds for example _seems_ to work in
> > proc/pid with this patch applied...
> 
> I suspect this is more of an optimization: the old code tries not to
> burden the global dentry cache with all the anonymous pipes, sockets,
> etc. since they won't ever be looked up from the cache.

But I also couldn't see that the flag causes the dcache to put the
entry in the hash or not...