From mboxrd@z Thu Jan  1 00:00:00 1970
From: "J. Bruce Fields" <bfields@fieldses.org>
Subject: elementary d_move question
Date: Wed, 23 Oct 2013 11:46:54 -0400
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Cc: linux-fsdevel@vger.kernel.org
To: Al Viro <viro@zeniv.linux.org.uk>
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If I rename foo over bar, while holding bar open, then
/proc/<pid>/fd/<fd> still shows me bar's old path:

	$ touch foo bar
	$ tail -f bar &
	[1] 23492
	$ mv foo bar
	$ readlink /proc/23492/fd/3
	/home/bfields/bar (deleted)

The rename does a d_move(dentry, target) where I assume dentry is for
"foo" and target for "bar", with target the same dentry that the file
descriptor holds a reference on.

But d_move() does

	switch_names(dentry, target);

giving target name "foo".  So how does readlink still get "bar"?

I've clearly missed something obvious....

--b.