Re: [PATCH v5 02/10] io_uring: add support for IORING_OP_MKDIRAT

[Pavel Begunkov <asml.silence@gmail.com>]

On 6/22/21 12:41 PM, Pavel Begunkov wrote:
> On 6/3/21 6:18 AM, Dmitry Kadashev wrote:
>> IORING_OP_MKDIRAT behaves like mkdirat(2) and takes the same flags
>> and arguments.
>>
>> Signed-off-by: Dmitry Kadashev <dkadashev@gmail.com>
>> ---
>>  fs/io_uring.c                 | 55 +++++++++++++++++++++++++++++++++++
>>  include/uapi/linux/io_uring.h |  1 +
>>  2 files changed, 56 insertions(+)
>>
>> diff --git a/fs/io_uring.c b/fs/io_uring.c
>> index a1ca6badff36..8ab4eb559520 100644
>> --- a/fs/io_uring.c
>> +++ b/fs/io_uring.c
>> @@ -665,6 +665,13 @@ struct io_unlink {
>>  	struct filename			*filename;
>>  };
>>  
>> +struct io_mkdir {
>> +	struct file			*file;
>> +	int				dfd;
>> +	umode_t				mode;
>> +	struct filename			*filename;
>> +};
>> +
>>  struct io_completion {
>>  	struct file			*file;
>>  	struct list_head		list;
>> @@ -809,6 +816,7 @@ struct io_kiocb {
>>  		struct io_shutdown	shutdown;
>>  		struct io_rename	rename;
>>  		struct io_unlink	unlink;
>> +		struct io_mkdir		mkdir;
>>  		/* use only after cleaning per-op data, see io_clean_op() */
>>  		struct io_completion	compl;
>>  	};
>> @@ -1021,6 +1029,7 @@ static const struct io_op_def io_op_defs[] = {
>>  	},
>>  	[IORING_OP_RENAMEAT] = {},
>>  	[IORING_OP_UNLINKAT] = {},
>> +	[IORING_OP_MKDIRAT] = {},
>>  };
>>  
>>  static bool io_disarm_next(struct io_kiocb *req);
>> @@ -3530,6 +3539,44 @@ static int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags)
>>  	return 0;
>>  }
>>  
>> +static int io_mkdirat_prep(struct io_kiocb *req,
>> +			    const struct io_uring_sqe *sqe)
>> +{
>> +	struct io_mkdir *mkd = &req->mkdir;
>> +	const char __user *fname;
>> +
>> +	if (unlikely(req->flags & REQ_F_FIXED_FILE))
>> +		return -EBADF;
>> +
>> +	mkd->dfd = READ_ONCE(sqe->fd);
>> +	mkd->mode = READ_ONCE(sqe->len);
>> +
>> +	fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
>> +	mkd->filename = getname(fname);
>> +	if (IS_ERR(mkd->filename))
>> +		return PTR_ERR(mkd->filename);
> 
> We have to check unused fields, e.g. buf_index and off,
> to be able to use them in the future if needed. 
> 
> if (sqe->buf_index || sqe->off)
> 	return -EINVAL;
> 
> Please double check what fields are not used, and
> same goes for all other opcodes.

+ opcode specific flags, e.g.

if (sqe->rw_flags)
	return -EINVAL;

-- 
Pavel Begunkov