Re: [PATCH v4 1/1] io-uring: Make statx API stable

[Luis Chamberlain <mcgrof@kernel.org>]

On Fri, Feb 25, 2022 at 10:53:26AM -0800, Stefan Roesch wrote:
> One of the key architectual tenets is to keep the parameters for
> io-uring stable. After the call has been submitted, its value can
> be changed. Unfortunaltely this is not the case for the current statx
> implementation.
> 
> IO-Uring change:
> This changes replaces the const char * filename pointer in the io_statx
> structure with a struct filename *. In addition it also creates the
> filename object during the prepare phase.
> 
> With this change, the opcode also needs to invoke cleanup, so the
> filename object gets freed after processing the request.
> 
> fs change:
> This replaces the const char* __user filename parameter in the two
> functions do_statx and vfs_statx with a struct filename *. In addition
> to be able to correctly construct a filename object a new helper
> function getname_statx_lookup_flags is introduced. The function makes
> sure that do_statx and vfs_statx is invoked with the correct lookup flags.
> 
> Signed-off-by: Stefan Roesch <shr@fb.com>

At least it doesn't break my KVM boots anymore:

Tested-by: Luis Chamberlain <mcgrof@kernel.org>

  Luis