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Date: Tue, 22 Mar 2005 18:44:52 -0800
From: Andrew Morton <akpm@osdl.org>
To: Jan Engelhardt <jengelh@linux01.gwdg.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Invalidating dentries
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Jan Engelhardt <jengelh@linux01.gwdg.de> wrote:
>
> how can I invalidate all buffered/cached dentries so that ls -l /somefolder 
>  will definitely go read the harddisk?

Patch the kernel?

There's no way of doing this apart from unmount/mount, or by forcing a ton
of memory pressure and hoping that the dentries get reclaimed.

A quick way of doing it would be to add a new mount option to the
filesystem and call shrink_dcache_sb() from there.  do `mount -o
remount,shrink_dcache'.