Re: [PATCH v1 3/3] io_uring: add support for getdents64

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

On 11/23/21 18:10, Stefan Roesch wrote:
> This adds support for getdents64 to io_uring.

Looks good,
Reviewed-by: Pavel Begunkov <asml.silence@xxxxxxxxx>

> Signed-off-by: Stefan Roesch <shr@xxxxxx>
> ---
>   fs/io_uring.c                 | 52 +++++++++++++++++++++++++++++++++++
>   include/uapi/linux/io_uring.h |  1 +
>   2 files changed, 53 insertions(+)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index b07196b4511c..b19fa94bcd95 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -688,6 +688,13 @@ struct io_hardlink {
>   	int				flags;
>   };
>   
> +struct io_getdents {
> +	struct file			*file;
> +	struct linux_dirent64 __user	*dirent;
> +	unsigned int			count;
> +	loff_t				pos;
> +};
> +
>   struct io_async_connect {
>   	struct sockaddr_storage		address;
>   };
> @@ -847,6 +854,7 @@ struct io_kiocb {
>   		struct io_mkdir		mkdir;
>   		struct io_symlink	symlink;
>   		struct io_hardlink	hardlink;
> +		struct io_getdents	getdents;
>   	};
>   
>   	u8				opcode;
> @@ -1096,6 +1104,9 @@ static const struct io_op_def io_op_defs[] = {
>   	[IORING_OP_MKDIRAT] = {},
>   	[IORING_OP_SYMLINKAT] = {},
>   	[IORING_OP_LINKAT] = {},
> +	[IORING_OP_GETDENTS] = {
> +		.needs_file		= 1,
> +	},
>   };
>   
>   /* requests with any of those set should undergo io_disarm_next() */
> @@ -3940,6 +3951,42 @@ static int io_linkat(struct io_kiocb *req, unsigned int issue_flags)
>   	return 0;
>   }
>   
> +static int io_getdents_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> +{
> +	struct io_getdents *getdents = &req->getdents;
> +
> +	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
> +		return -EINVAL;
> +	if (sqe->ioprio || sqe->rw_flags || sqe->buf_index)
> +		return -EINVAL;
> +
> +	getdents->pos = READ_ONCE(sqe->off);
> +	getdents->dirent = u64_to_user_ptr(READ_ONCE(sqe->addr));
> +	getdents->count = READ_ONCE(sqe->len);
> +
> +	return 0;
> +}
> +
> +static int io_getdents(struct io_kiocb *req, unsigned int issue_flags)
> +{
> +	struct io_getdents *getdents = &req->getdents;
> +	int ret;
> +
> +	if (issue_flags & IO_URING_F_NONBLOCK)
> +		return -EAGAIN;
> +
> +	ret = vfs_getdents(req->file, getdents->dirent, getdents->count, getdents->pos);
> +	if (ret < 0) {
> +		if (ret == -ERESTARTSYS)
> +			ret = -EINTR;
> +
> +		req_set_fail(req);
> +	}
> +
> +	io_req_complete(req, ret);
> +	return 0;
> +}
> +
>   static int io_shutdown_prep(struct io_kiocb *req,
>   			    const struct io_uring_sqe *sqe)
>   {
> @@ -6446,6 +6493,8 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
>   		return io_symlinkat_prep(req, sqe);
>   	case IORING_OP_LINKAT:
>   		return io_linkat_prep(req, sqe);
> +	case IORING_OP_GETDENTS:
> +		return io_getdents_prep(req, sqe);
>   	}
>   
>   	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
> @@ -6728,6 +6777,9 @@ static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
>   	case IORING_OP_LINKAT:
>   		ret = io_linkat(req, issue_flags);
>   		break;
> +	case IORING_OP_GETDENTS:
> +		ret = io_getdents(req, issue_flags);
> +		break;
>   	default:
>   		ret = -EINVAL;
>   		break;
> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> index c45b5e9a9387..792875075a2f 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -140,6 +140,7 @@ enum {
>   	IORING_OP_MKDIRAT,
>   	IORING_OP_SYMLINKAT,
>   	IORING_OP_LINKAT,
> +	IORING_OP_GETDENTS,
>   
>   	/* this goes last, obviously */
>   	IORING_OP_LAST,

--
Pavel Begunkov