Re: [PATCH] dcache: Translating dentry into pathname without taking rename_lock

["George Spelvin" <linux@horizon.com>]

As long as you're removing locks from prepend_name and complicating its
innards, I notice that each and every call site follows it by prepending
"/".  How about moving that into prepend_name as well?

Also, if you happen to feel like it, you can delete the slash flag
and replace it with "bptr != *buffer".

Another small tweak would be to the global_root part of the code.
You could move the is_mounted(vfsmnt) test up, and combine the tail of
that code path with the regular exit.  All you have to do is change
the !slash test to:

	if (error >= 0 && bptr == *buffer) {	/* Root directory */
		if (--blen < 0)
			error = -ENAMETOOLONG;
		else
			*--bptr = '/';
	}

This modified form is no more code than an inlined copy of prepend(),
so we haven't actually slowed the fast path, but it avoids corrupting
the return value of 0/1/2 if possible.