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Re: Cleaning up namei

On Wed, Mar 19, 2008 at 11:02:20PM +0000, David Holland wrote:
> Yes, I would prefer to keep all the emulroot stuff contained inside
> namei. It is, after all, roughly the same as onionfs. :-/
> I've noticed, btw, that there's not really a whole lot of consistency
> in the use of TRYEMULROOT, and I suspect many of the cases are wrong.
> Is there a clear rule for when it is and isn't supposed to be used?

If you look at the pre-TRYEMULROOT compat code you'll see that large
numbers of, but not quite all, system call entries tried a lookup with
a modified pathname, if it worked it copied the alternate path out
into the stackgap...

When I moved the code into namei I enabled it in the paths where it
was previously enabled.  (Probably fixing a few errors in the process).
Any rules had to be inferred...

The 'fun' issues where correctly processing absolute symlinks from inside
the emulation root.
(There is almost scope for a mount option to force absolute symlinks
to be bounded to the fs.)


David Laight:

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