From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro@ZenIV.linux.org.uk>
Subject: Re: [PATCH] procfs: stop using vmtruncate
Date: Tue, 21 Jun 2011 03:05:26 +0100
Message-ID: <20110621020526.GY11521@ZenIV.linux.org.uk>
References: <20110620224727.GA22187@infradead.org>
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Cc: linux-fsdevel@vger.kernel.org
To: Christoph Hellwig <hch@infradead.org>
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On Mon, Jun 20, 2011 at 06:47:27PM -0400, Christoph Hellwig wrote:
> Procfs doens't have any ->truncate instances, so all vmtruncate calls can
> be replaced with truncate_setsize, given that we've just done the
> inode_newsize_ok check as part of inode_change_ok just before.

What files on procfs allow meaningful truncate anyway?  I agree that
vmtruncate() there is bogus, but AFAICT we have the following picture:
	* there are files with non-zero i_size (/proc/kcore and
/proc/bus/pci/*/*); for any of those ATTR_SIZE should fail and I don't
think it should fail silently.
	* the rest has size 0 and for those ATTR_SIZE to non-0 length
should definitely fail with an error.