Re: [PATCH v5 10/10] io_uring: add support for IORING_OP_MKNODAT

[Jens Axboe <axboe@kernel.dk>]

On 6/23/21 12:26 AM, Dmitry Kadashev wrote:
> On Tue, Jun 22, 2021 at 6:52 PM Pavel Begunkov <asml.silence@gmail.com> wrote:
>>
>> On 6/3/21 6:18 AM, Dmitry Kadashev wrote:
>>> IORING_OP_MKNODAT behaves like mknodat(2) and takes the same flags and
>>> arguments.
>>>
>>> Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
>>> Link: https://lore.kernel.org/io-uring/20210514145259.wtl4xcsp52woi6ab@wittgenstein/
>>> Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
>>> ---
>>>  fs/internal.h                 |  2 ++
>>>  fs/io_uring.c                 | 56 +++++++++++++++++++++++++++++++++++
>>>  fs/namei.c                    |  2 +-
>>>  include/uapi/linux/io_uring.h |  2 ++
>>>  4 files changed, 61 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/internal.h b/fs/internal.h
>>> index 15a7d210cc67..c6fb9974006f 100644
>>
>> [...]
>>
>>>  static bool io_disarm_next(struct io_kiocb *req);
>>> @@ -3687,6 +3697,44 @@ static int io_linkat(struct io_kiocb *req, int issue_flags)
>>>       io_req_complete(req, ret);
>>>       return 0;
>>>  }
>>> +static int io_mknodat_prep(struct io_kiocb *req,
>>> +                         const struct io_uring_sqe *sqe)
>>> +{
>>> +     struct io_mknod *mkn = &req->mknod;
>>> +     const char __user *fname;
>>> +
>>> +     if (unlikely(req->flags & REQ_F_FIXED_FILE))
>>> +             return -EBADF;
>>
>> IOPOLL won't support it, and the check is missing.
>> Probably for other opcodes as well.
>>
>> if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
>>         return -EINVAL;
> 
> This change is based on some other similar opcodes (unlinkat, renameat) that
> were added a while ago. Those lack the check as well. I guess I'll just prepare
> a patch that adds the checks to all of them. Thanks, Pavel.
> 
> Jens, separately it's my understanding that you do not want the MKNODAT opcode
> at all, should I drop this from the subsequent series?

Right, just drop that one for now. Would be great if you could resend
the series with the suggested fixes folded in. Might as well just do
a clean sweep.

-- 
Jens Axboe