On Mon 18-09-23 14:32:16, Max Kellermann wrote:
> This implements a missing piece in the inotify API: referring to a
> file by a directory file descriptor and a path name. This can be
> solved in userspace currently only by doing something similar to:
>
> int old = open(".");
> fchdir(dfd);
> inotify_add_watch(....);
> fchdir(old);
>
> Support for LOOKUP_EMPTY is still missing. We could add another IN_*
> flag for that (which would clutter the IN_* flags list further) or
> add a "flags" parameter to the new system call (which would however
> duplicate features already present via special IN_* flags).
>
> To: Jan Kara <jack@xxxxxxx>
> Cc: Amir Goldstein <amir73il@xxxxxxxxx>
> To: linux-fsdevel@xxxxxxxxxxxxxxx
> To: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx>
Thanks for the patches! But generally we don't add new functionality to the
inotify API and rather steer users towards fanotify. In this particular
case fanotify_mark(2) already has the support for dirfd + name. Is there
any problem with using fanotify for you? Note that since kernel 5.13 you
don't need CAP_SYS_ADMIN capability for fanotify functionality that is
more-or-less equivalent to what inotify provides.
Honza
> ---
> fs/notify/inotify/inotify_user.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
> index b6e6f6ab21f8..8a9096c5ebb1 100644
> --- a/fs/notify/inotify/inotify_user.c
> +++ b/fs/notify/inotify/inotify_user.c
> @@ -797,6 +797,12 @@ SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname,
> return do_inotify_add_watch(fd, AT_FDCWD, pathname, mask);
> }
>
> +SYSCALL_DEFINE4(inotify_add_watch_at, int, fd, int, dfd, const char __user *, pathname,
> + u32, mask)
> +{
> + return do_inotify_add_watch(fd, dfd, pathname, mask);
> +}
> +
> SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd)
> {
> struct fsnotify_group *group;
> --
> 2.39.2
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
