On 6/22/21 12:41 PM, Pavel Begunkov wrote:

On 6/3/21 6:18 AM, Dmitry Kadashev wrote:

quoted

IORING_OP_MKDIRAT behaves like mkdirat(2) and takes the same flags
and arguments.

Signed-off-by: Dmitry Kadashev <redacted>
---
 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