Subject: Re: [PATCH against 2.6.14] truncate() or ftruncate shouldn't
	change mtime if size doesn't change.
From: Trond Myklebust <trondmy@trondhjem.org>
To: NeilBrown <neilb@suse.de>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org
In-Reply-To: <1130763105.8802.23.camel@lade.trondhjem.org>
References: <20051031173358.9566.patches@notabene>
	 <1051031063444.9586@suse.de>  <1130763105.8802.23.camel@lade.trondhjem.org>
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Date: Mon, 31 Oct 2005 08:37:38 -0500
Message-Id: <1130765858.8802.36.camel@lade.trondhjem.org>
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On Mon, 2005-10-31 at 07:51 -0500, Trond Myklebust wrote:
> This should normally be OK as far as NFS is concerned since we usually
> end up revalidating the attribute cache in the lookup() code, but you
> could imagine a networked filesystem that does not do this. I'd
> therefore prefer if such checks were made in the filesystem itself.

Actually, I'm wrong about this. ftruncate() doesn't do a
lookup/lookup_revalidate, so the current NFS code may end up using stale
attribute data.

Moving the checks to the VFS will just make that problem unfixable,
though.

Cheers,
  Trond
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