On Fri, Aug 15, 2025 at 1:51 AM Thomas Bertschinger
<tahbertschinger@xxxxxxxxx> wrote:
>
> Add support for name_to_handle_at(2) to io_uring.
>
> Like openat*(), this tries to do a non-blocking lookup first and resorts
> to async lookup when that fails.
>
> This uses sqe->addr for the path, ->addr2 for the file handle which is
> filled in by the kernel, and ->addr3 for the mouint_id which is filled
> in by the kernel.
>
> Signed-off-by: Thomas Bertschinger <tahbertschinger@xxxxxxxxx>
> ---
> include/uapi/linux/io_uring.h | 1 +
> io_uring/opdef.c | 7 ++++++
> io_uring/openclose.c | 43 +++++++++++++++++++++++++++++++++++
> io_uring/openclose.h | 3 +++
> 4 files changed, 54 insertions(+)
>
> diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
> index 6957dc539d83..596bae788b48 100644
> --- a/include/uapi/linux/io_uring.h
> +++ b/include/uapi/linux/io_uring.h
> @@ -289,6 +289,7 @@ enum io_uring_op {
> IORING_OP_READV_FIXED,
> IORING_OP_WRITEV_FIXED,
> IORING_OP_PIPE,
> + IORING_OP_NAME_TO_HANDLE_AT,
>
> /* this goes last, obviously */
> IORING_OP_LAST,
> diff --git a/io_uring/opdef.c b/io_uring/opdef.c
> index 9568785810d9..ff2672bbd583 100644
> --- a/io_uring/opdef.c
> +++ b/io_uring/opdef.c
> @@ -574,6 +574,10 @@ const struct io_issue_def io_issue_defs[] = {
> .prep = io_pipe_prep,
> .issue = io_pipe,
> },
> + [IORING_OP_NAME_TO_HANDLE_AT] = {
> + .prep = io_name_to_handle_at_prep,
> + .issue = io_name_to_handle_at,
> + },
> };
>
> const struct io_cold_def io_cold_defs[] = {
> @@ -824,6 +828,9 @@ const struct io_cold_def io_cold_defs[] = {
> [IORING_OP_PIPE] = {
> .name = "PIPE",
> },
> + [IORING_OP_NAME_TO_HANDLE_AT] = {
> + .name = "NAME_TO_HANDLE_AT",
> + },
> };
>
> const char *io_uring_get_opcode(u8 opcode)
> diff --git a/io_uring/openclose.c b/io_uring/openclose.c
> index d70700e5cef8..f15a9307f811 100644
> --- a/io_uring/openclose.c
> +++ b/io_uring/openclose.c
> @@ -27,6 +27,15 @@ struct io_open {
> unsigned long nofile;
> };
>
> +struct io_name_to_handle {
> + struct file *file;
> + int dfd;
> + int open_flag;
These are not open_flags, there are handle_flags
(e.g. AT_HANDLE_FID)
> + struct file_handle __user *ufh;
> + char __user *path;
> + void __user *mount_id;
> +};
> +
> struct io_close {
> struct file *file;
> int fd;
> @@ -187,6 +196,40 @@ void io_open_cleanup(struct io_kiocb *req)
> putname(open->filename);
> }
>
> +int io_name_to_handle_at_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> +{
> + struct io_name_to_handle *nh = io_kiocb_to_cmd(req, struct io_name_to_handle);
> +
> + nh->dfd = READ_ONCE(sqe->fd);
> + nh->open_flag = READ_ONCE(sqe->open_flags);
Please also create union member sqe->handle_flags
or name_to_handle_flags.
Thanks,
Amir.
