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Date: Fri, 15 Aug 2014 10:29:50 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: "Luis R. Rodriguez" <mcgrof@do-not-panic.com>
Cc: clm@fb.com, jbacik@fb.com, hch@infradead.org,
	linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
	linux-kernel@vger.kernel.org, jeffm@suse.com, fdmanana@suse.com,
	"Luis R. Rodriguez" <mcgrof@suse.com>
Subject: Re: [RFC v3 0/2] vfs / btrfs: add support for ustat()
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On Thu, Aug 14, 2014 at 07:58:56PM -0700, Luis R. Rodriguez wrote:

> Christoph had noted that this seemed associated to the problem
> that the btrfs uses different assignments for st_dev than s_dev,
> but much as I'd like to see that changed based on discussions so
> far its unclear if this is going to be possible unless strong
> commitment is reached.

Explain, please.  Whose commitment and commitment to what, exactly?
Having different ->st_dev values for different files on the same
fs is a bloody bad idea; why does btrfs do that at all?  If nothing else,
it breaks the usual "are those two files on the same fs?" tests...