On Mon, Dec 14, 2020 at 12:13:23PM -0700, Jens Axboe wrote:
> Now that we support non-blocking path resolution internally, expose it
> via openat2() in the struct open_how ->resolve flags. This allows
> applications using openat2() to limit path resolution to the extent that
> it is already cached.
>
> If the lookup cannot be satisfied in a non-blocking manner, openat2(2)
> will return -1/-EAGAIN.
>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> ---
> fs/open.c | 6 ++++++
> include/linux/fcntl.h | 2 +-
> include/uapi/linux/openat2.h | 4 ++++
> 3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/fs/open.c b/fs/open.c
> index 9af548fb841b..a83434cfe01c 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -1087,6 +1087,12 @@ inline int build_open_flags(const struct open_how *how, struct open_flags *op)
> lookup_flags |= LOOKUP_BENEATH;
> if (how->resolve & RESOLVE_IN_ROOT)
> lookup_flags |= LOOKUP_IN_ROOT;
> + if (how->resolve & RESOLVE_NONBLOCK) {
> + /* Don't bother even trying for create/truncate open */
> + if (flags & (O_TRUNC | O_CREAT))
> + return -EAGAIN;
Why not O_TMPFILE here as well?
